Datasets:

VatsaDev

/

worldbuild

like 11

[Question] [ Could two planets be tidally locked to each other at such a small distance from one another that they share their atmosphere, and material is floating around between the two?  [Answer] The Roche Limit alluded to in other answers may not be a barrier to this. **Rigid Approximation** For two rigid planets of the same mass *M* and radius *R*, both held together by the force of gravity, the Roche Limit would be the distance between their centres *D* where any reduction in that distance would mean that tidal force on each planet was greater than the gravity holding the planet together. From <https://en.wikipedia.org/wiki/Roche_limit#Rigid-satellite_calculation>: Where the tidal force equals the gravitational force: > > *GM/R2 = GM(2DR - R2)/(D4 - 2D3R + R2D2)* > > > This simplifies to: > > *R4 - 2DR3 + R2D2 - 2D3R + D4 = 0*, > > > which, has a solution D = 1.8832R. The separation of surfaces is 2R less than that: -0.1168R. The Roche Limit is when the circumference of each planet is within the other planet. Two equally-sized rigid planets whose surfaces are separated by any distance at all are well outside each other's Roche Limit. **Fluid Approximation** For fluid bodies, from <https://en.wikipedia.org/wiki/Roche_limit#Fluid_satellites>, > > The calculation is complex and its result cannot be represented in an > exact algebraic formula > > > but the result given is: > > *D = 2.44R* > > > That, again, is the distance between their centres. When both objects have radius R then their surface to surface separation is 0.44R (2,800km for Earth). Even completely fluid Earth's could orbit each other almost completely within each other's exosphere (about 10,000km) without crossing each other's Roche Limit. **Combined** So for a rigid body the Roche Limit in surface separation is -0.1168R (overlapping) For fluid planets the Roche Limit in surface separation is 0.44R. A real rocky planet like the Earth would be somewhere between the two. A precise answer would take complex computer modelling of all the constituent layers. The best I can do here is guess at half way between the two (half rigid, half fluid): 0.1616R. Just over 1,000km for two earths: at about the edge of each other's thermosphere. That would be right on the Roche Limit. I doubt planets would exist very happily at that limit but, theoretically, they would exist. Whether that could ever arise in a stable configuration is another matter. Capturing another object (like Neptune capturing Triton) in orbit is very rare and to do it in such a way that resulted in such minuscule separation and perfectly circular orbits would be ridiculously unlikely. For them to condense out of gas and dust in that configuration when they would be fluid and not rigid seems even more unlikely. However, they would be growing and accreting and becoming more rigid as they do so (and then less as their cores melt) their Roche Limits would be changing up and down as they did. It is not necessarily impossible. [Answer] No. HDE 226868's answer explains the concept of Roche Lobe and touches that of Roche Limit, but things are a bit more complicated. **Giant stars** are stars so big that their outer layers feel very weakly the gravity of the internal ones. These stars, when on close binary systems, are so big that their stellar atmospheres are bigger than their Roche lobes, so they lose mass towards the other star on the binary system, if that one is small enough (second case in the image). Usually stars are not so big so they are each in its own Roche lobe (first case), but if both stars are giant stars, they can share their stellar atmospheres. This is a real case of atmosphere sharing, but keep in mind that the distance between the star nuclei is still very big. It is just that atmospheres are big as well.  **Giant planets** like Jupiter have bigger gravity on their atmospheres than giant stars. This is because the radius is quite smaller, even if the mass is small as well. So it is very unlikely that a giant planet can share atmosphere with another: they would need to be very close, really close. Close enough that they will have big tidal problems. Such planets are mainly composed of gas, so they will most probably experience serious disturbances caused by the other planet, and can not be tidally locked at all. **Rocky planets** like Earth have a different problem: that of Roche Limit.  When a solid body kept together by its own gravity, like a rocky planet, becomes near enough another solid body of the same or bigger mass, it experiences tidal effects. Tidal locking is the minor of them. But when coming closer and closer the tidal effect causes some parts of the planet to travel faster than others, causing the breakage of the minor body. Roche's limit depends on body's density. For example, Roche Limit for Moon on Earth is between 9496Km (if Moon were perfectly rigid) and 18261Km (if it were perfectly deformable). Anything nearer than that will tear apart. And since Earth's atmosphere is a fine layer of just 10000Km (for the Exosphere, that hardly can be called "an atmosphere"), two planets like those of your image would quite quickly become one unique bigger ball. More if the distance you pretend is that of Troposphere's 12Km. [Answer] Ahh, here we go. **No. But yes.** I'll leave the stuff about the Roche limit for Vincent; after all, it was his idea. Assuming he writes up an answer, you'll learn why these planets cannot be tidally locked and so near each other. This means that you won't see two planets coming really close to each other, like this image depicts. They certainly won't touch. But atmospheric transfer is totally possible. I know, this seems counterintuitive, given that it's just been established that these planets can be so close to one another. But there's a little loophole called a [Roche lobe](https://en.wikipedia.org/wiki/Roche_lobe) that can make this scenario possible. The Roche lobe (not the same as the Roche limit!) is the point in a binary star system inside of which matter is bound to the star by gravity. If matter escapes the lobe, it may be accreted by the other star, and vice versa. Mass transfer is usually in the form of gas, plasma, or other stellar material, including material from coronal mass ejections or other dramatic events. Here, though, it will be the atmosphere that is transferred. The whole idea, by the way, is explored in Robert Forward's [Rocheworld](https://en.wikipedia.org/wiki/Rocheworld), which I managed to find out after writing the rest of this answer. [Answer] The answer is yes and the Pluto Charon system is an example of such an arrangement. See [this](https://www.newscientist.com/article/dn25684-pluto-and-its-moon-snuggle-under-a-shared-atmosphere/) article from New Scientist Two earth like planets sharing an atmosphere is explored in a fictional setting in [The Ragged Astronauts](https://www.goodreads.com/book/show/854067.The_Ragged_Astronauts) trilogy by Bob Shaw [Answer] Depends what is meant by "atmosphere" Officially, the earth's atmosphere extends one third of the way to the moon, which is extraordinarily further than what is implied by the illustration provided. However, at this distance, the air certainly isn't "breathable" and probably not what is commonly meant by "atmosphere." So certainly, if you had two earth like planets, spinning around each other at the distance that the moon orbits, gas exchange is beginning to sound likely. Also, high tide would be 8 times more significant than it is on earth, given our current moon. perhaps someone else could speak of the probability of such a planetary system occurring, but one in place, I see no reason why it would be unstable. [Answer] If the terrestrial planet requirement can be relaxed allowing for smaller worlds with fluffier atmospheres, consider two Titan-sized planets in close orbit. With its radius of 2500km, minimal Roche distance of the surfaces is 1100km. [Titan's atmosphere](https://en.wikipedia.org/wiki/Atmosphere_of_Titan) at 600km is at mesopause just above upper haze layers. Under the counteracting gravity of the companion, the atmosphere would stretch farther, likely connecting the stratospheres, opening the possibility of cross-planet travel by balloon. ]

[Question] [ If someone wanted to construct a skyscraper (bigger being better) that would survive thousands of years *without maintenance*, what would they make it out of? It can be built from any plausible current/cutting edge/semi-futuristic materials but should be something that you can actually picture people using for large scale construction so no platinum/iridium alloys ;) Concrete's probably out too as it would likely start showing problems after a few hundred years. The idea being in the near(ish) future lots of new buildings are built from said materials (because they're tough/cheap/abundant/renewable/recyclable etc.) Sometime after, there is some kind of cataclysm (haven't worked out an appropriate one yet). Some 10,000 years into the future, a few of these great buildings remain (even just one or two would be ok), inspiring awe in whatever underdeveloped civilisation is still around at the time. [Answer] # Build a Pyramid The Pyramids are halfway to your desired 10,000 year life span already. They are a little worse for wear, but they are definitely still standing. First, lets assess the criticism that the pyramids are not skyscrapers. The great pyramid at Giza (139m) was the tallest building in the world until the Lincoln Cathedral was completed in 1311. Then, after the Lincoln Cathedral burned down, and St. Mary's church in Stralsund was hit by lightning, the Great Pyramid was on top again until 1874 when St. Nikolai's was completed in Hamburg. Skyscrapers started off much smaller. The Home Insurance Building in Chicago, the first building supported by a fireproof metal frame was 42m in 1884. The 1895 American Surety Building in New York was 92m. The 1903 Flatiron building in New York went to 94m, and finally in 1908 the Singer tower went to 187m and beat the pyramids. Even today, the pyramids would be tall for a modern American city. A 150m pyramid would be the 14th tallest building in Boston, 19th tallest in Dallas, 7th tallest in Denver or Minneapolis, etc. Second, lets assess the claim that the pyramids are just a pile of rocks. The ancient pyramids did clearly have internal structures, although not very large. If you were purpose building a pyramid to house more, you could make more room on the inside. The internal volume is 88 million cubic feet, as opposed to 37 million for the Empire state building. So there is plenty of room to build things and have lots of rocks left over. Finally, lets address the age of the pyramids. They have lasted 5000 years built with 5000 year old technology. That is significant. The builders did not have metal to work with, only the most rudimentary mathematics, etc. And yet look how long their creation lasted? Instead of using limestone, a modern pyramid could be made of granite. If the pyramid was continuously occupied, it wouldn't be vandalized (much of the current damage was done by vandals who stripped the outer casing). Metal struts could be added to support the interior and allow more usable space inside. In conclusion, if you want a building to last a long time, make your building into a mountain. --- As is noted by Tim B. if you want your building (or anything) to last a long time, build it in the Egyptian desert with no winters. [Answer] [Self-healing concrete](http://www.citg.tudelft.nl/en/research/projects/self-healing-concrete/). It works by embedding tiny capsules in the concrete containing bacterial spores. When the capsules are broken by water penetrating the concrete, the bacteria are released and begin to metabolise - and one of their waste products is calcite (a component in limestone). The calcite seals the crack, good as new. The technology is definitely in its infancy - it can currently only heal very small cracks, and once a capsule is used it's gone for good. Nearish-future technology could certainly expand the size of the cracks that can be fixed, and perhaps include a way for the capsules to be reused. Secondly, while it's true that modern concrete tends to crumble within a couple of decades, that's not an immutable fact of what will always happen to concrete or concrete-like materials. 2,000 years ago, the engineers of the Roman empire discovered what they called *opus caementicium*, and what we today call concrete. Their mix included volcanic ash, and structures built with this material is still standing today. The Pantheon in Rome is the classic example, built around 100 AD, with a massive concrete dome. It's still standing and structurally sound. We still don't fully understand how Roman concrete manages this feat - new scientific papers are being published studying the structure of the material with electron microscopes, finding new features nobody had any clue about. There are suggestions for how to reproduce it, but at present none of them are economically viable. Combine advances in self-healing concrete with a breakthrough in affordable Roman-style concrete, and you could have a pretty impressive material. Combine that with some of the structural ideas in other answers, like pyramids, and structures surviving 10,000 years seems quite workable. [Answer] I don't think an inanimate building is an option either. I'm going to admit this may not be within the technological scope you want, it certainly wouldn't exactly look the way you want and there are some real issues about why this would be a desirable choice, but if you're willing to stretch, how about **a genetically modified tree**. The current tallest redwood is about 380ft tall. Certainly not a mega skyscraper, but genetics, proper farming and a little imagination might get you to 500ft. They're big enough to live in, and trees are fairly resilient to having stuff carved out of them. The oldest living bristlecone pines are thought to be 5000 years old. Maybe there are older trees? Maybe their not so huge stature is a barrier to longevity? The widest tree is an 80ft in diameter redwood. That's bigger than an apartment; people could live in it. On a more tree friendly world, one with a lot more CO2, the tree could be much larger and hardier than is possible today. [Answer] [*Life After People*](https://en.wikipedia.org/wiki/Life_After_People) did come up with an answer, but you are not going to like it. Of all the human artifacts that were profiled on *Life After People*, the one which had the longest potential lifespan was the Apollo Lunar Landers. They will sit on the Moon, preserved in vacuum as recognizable artifacts for almost a *quarter billion years*. Deep space probes like Voyager and New Horizon speeding out into interstellar space might also last as long, before the effects of cosmic radiation, being pelted by high speed dust particles and other effects of the space environment erode them away. So creating a structure on the Moon will certainly outlast anything built on a geologically active planet like Earth. Considering that any structure will need at least 5 meters of shielding to cover it, it is conceivable that it will survive eons before being eroded away, and might even still be recognizable as an artifact 5 billion years from now when the Sun engulfs it in its red giant phase. [Answer] Why build a structure when it's possible to hollow out an existing structure like a mountain? There are over 200 underground structures in eastern Turkey. One of the best examples is [Derinkuyu](https://en.wikipedia.org/wiki/Derinkuyu_underground_city), a cave city that is estimated to have been able to accommodate a population of 20,000 people in 13 underground levels. The exact age of the underground cities are unknown but they have been found to contain artefacts from 800 BC. The cities were linked by underground tunnels that stretched for miles. There's a 5 mile long tunnel linking Derinkuyu with Kaymakli. If you want to insist on building a structure that would last the test of time then you could build your skyscraper using today's technology. Afterwards clad the building using rock cut into interlocking irregular shapes as seen at the [Sacsayhuaman](https://en.wikipedia.org/wiki/Saksaywaman) UNESCO World Heritage site in Peru. The irregular pattern will help the structure withstand earthquakes. Both structures were created almost 3,000 years ago, engineering feats that we would struggle to accomplish today using the tools which we know were available at the time. Peru and Turkey are both subject to regular seismic activity so we know the structures will last the test of time. If Derinkuyu could accommodate 20,000 people it would more than meet the skyscraper requirement considering that the World Trade Centre complex accommodated 50,000 people before its destruction in 2001. [Answer] **No**, there is absolutely no way to build such durable (modern) structures. Absolutely nothing humanity has built in the modern age, or will build in the next centuries will still be around 10 thousand years from now. > > **Note:** I'm talking about structures meant for habitation here, not nuclear waste storage sites, etc. > > > And disregarding any one material lasting that long (never mind keeping its shape and size), the complex system (that's what a building is - a system) as a whole would eventually decay. Such structures would come under assault from a variety of forces, year after year. We're talking temperature changes, humidity, strong winds, earthquakes, etc. It's sufficient for one bolt to come loose, one part to start vibrating, and eventually a whole mess of bolts and parts are slowly coming apart, with likely disastrous consequences. > > **Note:** I can't find it right now, but there was a study commissioned by an american agency, to study how a nuclear waste site might be labelled as a dangerous area in a manner which will last for several thousand years (beyond memory of the United States as a nation). The best they could come up with is carving the warning in a stone tablet 50 foot tall, and sealing the whole thing in some sort of super hard resin. Even then, they had some doubts of it surviving due to seismic activity. So you can throw the idea of a *building* surviving several times that time span right out the window. > > > [Answer] Depends on what your definition of skyscraper is. In the 1800s the definition was like 10-20 stories. Now, it's like 40-50. The biggest problem is height with little support--the tallest structures on earth have sway and are built to move, basically because of high winds at a certain height. Certain structural designs do stand the test of time--and those are pyramids. There's not as much that can go wrong over a millennia or more... But the very design of a skyscraper is not tenable for the sort of time frame you are talking about. It doesn't matter what it's made out of. There are too many interdependent parts as well--and it would just take one thing to bring it all down. But hey, let's give it a go. I want your skyscrapers to survive. So--sand. a big sand storm sweeps in, covering & filling your structure(s) and protecting them. Maybe they are covered for thousands and thousands of years, before another sandstorm partially reveals them, just in time for the heroes to see them. They might still be filled with sand, won't seem as tall, and definitely won't be structurally sound. Make it like Dubai or something...I dunno. They have some crazy buildings. Although Dubai didn't fare too well in *Life After People*... [Link to vid.](https://www.youtube.com/watch?v=BkAMJepZQH0) 10,000 years is a long damn time, so take it down. Also, watch the entire *Life After People* series. It's an education. Most structures like what you're talking about go after a couple hundred years. Even if you had perfect materials I can't see you doing more than doubling that... [Answer] None of the materials we currently have can produce a skyscraper that can last 10k years without maintenance. Not even promising materials currently on the horizon can. Good concrete without steel reinforcement can last for a long time, but it is heavy, stiff and brittle, 10k years will likely see more than a few major earthquakes that could crumble it. Solid rock is also quite durable, but while a good option for building something like a pyramid, it is impossible to build a skyscraper out of it. Compressed earth is quite durable too, especially with proper care, but even without it, there are some compressed earth structures dating back thousands of years. But again, not an option for building a skyscraper. And it goes without saying, steel won't cut it either, as "inert" as it may be it will eventually give in to weathering, corrosion, and whatnot. Some precious metals are very resistant chemically, but their mechanical properties are not suited for the task, not to mention their rarity and cost. Plastic, albeit an environmental disaster due to the time it takes to decompose, is not an option either - it will weather, it will degrade and it will fail. Not to mention it is flammable. It will make for a hell of a torch and subsequently an infernal lake of liquid burning plastic. Plastic might be used to encase steel frames, which will protect the steel from the elements for a while, but only until the plastic weathers to the point of cracking. Also plastic is usually soft, so any abrasive particles in the air would affect it. You basically don't want to use for a skyscraper anything other than steel frame structure. Not for skyscrapers are we understand the term today, much less compared to some futuristic standards. Definitely not concrete. The **big challenge** here is protecting steel from corrosion. Corrosion resistant alloys get you only halfway. Paint will weather and crack, a plastic coating will weather and crack. Steel must be protected by something that is: * moisture resistant and water repellent * fireproof * resistant to weathering and corrosion * hard enough to withstand wind abrasion * flexible enough to not crack and crumble as the structure flexes due to winds, quakes, and thermal expansion/contraction and as in time sags, which it will Extreme density rock wool comes to mind here. It can be infused with steel frames in the early production stage at a molecular level, when the steel is still red hot, using an extrusion process. It can be treated with mineral oils to protect from moisture, and its external layer can be partially molten to form a hard protective crust. Granted, oil will eventually weather off, but that can be fixed by providing extra oil in reservoirs so that oil content can be replenished through gravity and capillary action. Even at high density, the wool will not be a rigid solid internally, and while the outside will inevitably crack in time, it will not crumble as the fiber will be holding it together. The purpose of the external shell is only to protect from abrasive winds and wool disintegration, the mineral oil on the inside is what protects from corrosion. Mineral wool is also a great insulator, which will reduce the severity of thermal stresses, it is cheap, abundant and recyclable. The steel structure itself must not use any bolts or welds but instead be held together entirely by a modular construction and its weight. Earthquakes are the big obstacle to using materials, which would otherwise be good candidates due to their resistance to weathering. But if you are willing to go offshore, and of solid ground, you could have floating megastructures that would be immune to quakes. Granted, they won't be skyscrapers in the context of towers, more like floating bubbles, but they could get to formidable proportions. It is doable through additive manufacturing. The material could be tempered glass. Such a bubble will have the advantage of encapsulating a huge amount of space, providing natural sunlight, and creating the conditions to have an entire ecosystem isolated from the outside world, meaning that it could potentially survive a broad range of disasters, basically everything aside from a dense and continuous comet shower. Artificial lighting could even help sustain the ecosystem in the event of a temporary solar blackout, in the case of global volcanic eruption or nuclear winter. At that scale of construction, tsunamis will have the destructiveness taken out of them, using nuclear reactors the structure will be able to sustain life for hundreds or even thousands of years in a world that is otherwise inhospitable to life. Measures must be taken not to hit rock or get beached, that can be achieved either by anchoring somewhere in oceans' dead spots (plenty of floating plastic there that can be recycled as well) or by making the structure capable of sailing, and in case of loss of occupants, equip it with an auto-pilot software that will keep it off the shores by using nuclear reactors or renewable power sources. Now if we get maintenance back into the equation, it should at least theoretically be possible to make a skyscraper that can last 10k years. It doesn't have to be human maintenance though, it could be a team of robots, which use renewable power and have enough materials to self-produce for 10k years. That's at least somewhat plausible. The other viable option, a little more in the sci-fi realm, but still somewhat conceivable would be an engineered artificial life organism, something like a mega tree, but more resilient to the elements and elementals. It will essentially be self-maintaining, replacing weathered and compromised material at the nano-scale level, pretty much the organic version of the "robot maintenance" version above. However, that would be quite challenging, creating artificial and fully functional life aside, it will also have to be: * immune to time, effectively immortal * immune to fire * immune to extremely hot and extremely cold * immune to arid or wet climate * immune to diseases as in system malfunctions * immune to pH imbalances * immune to full solar blackouts * immune to viral and bacterial infections * immune to a wide range of pests, from bacteria through termites, cockroaches, rats and everything that may eat it Those challenges aside, if we presume that this is doable, such an organism can be employed into a variety of beneficial ways, for example, grow food, purify toxic water and air for the inhabitants, even grow electronic circuits, computers and communication systems and whatnot. [Answer] As others have said, it depends on how flexible your definition of "skyscraper" is. Essentially, the problem of maximizing the lifespan of a structure comes down to three factors: Environmental stresses, surface area versus volume, and gravity. 1. The quieter the environment, the less stresses the structure is subject to. 2. The less surface area is exposed to the environment, the less damage the structure will accrue. 3. The less gravity, the less a structure has to continuously bear the stress of its own weight, eventually leading to cracks, buckling, and breakup. Of course, the only way to reduce gravity is to launch into space, which is its own kind of solution. **Problem #1** can be mitigated by careful placement. The ideals are: * Dry weather: Low erosion/water damage. * Stable temperature: Low thermal/expansion stresses on the structural material. * Far from fault lines: Low earthquake damage. If you're willing to sacrifice the visibility of your structure, building it underground may be a worthwhile investment. (People might not see it immediately, but once they do...) Ancient pyramids solve **Problem #2** by having almost no empty space inside of them. Modern skyscrapers are built to be weight-optimized to support the largest amount of useful equipment and people with the lowest amount of structural weight; this means that once a few critical elements fail, the rest of the structure is in serious jeopardy. A pyramid is almost completely made out of rock holding up more rock, so it has plenty of extra material to help keep its shape through the ages. A tiny bunker deep in the interior of the building can keep some stuff safe for millennia, in this way. **Problem #3** will only be completely solved by a "skyscraper" in space, specifically on an asteroid. As Thucydides mentioned, the Moon is also a nearly ideal place to build -- no atmosphere to cause trouble, seismic activity has long ceased, and very low gravity, although not negligible. But you could probably build something much more like a skyscraper in space, with lots of *stuff* inside, and get away with it lasting tens of thousands of years or more. Cover it in 5-10m thick of dirt, and you should be safe from more or less any micrometeorite damage (5-10m is about the thickness of lunar regolith, which is the layer of the Lunar surface that has been pulverized to dirt by micrometeorites). We already have built skyscrapers in space. The height of a floor in a commercial building is commonly around 2.5 meters. All rockets built to launch humans are over 30 meters tall, or 12 floors high. The Mir space station was about 12x12x12 stories in dimensions. And the ISS measures roughly 110m by 70m in width, or 44 stories by 28 stories. For reference, a 40-story building looks like [this](http://www.downtownphoenixjournal.com/wp-content/uploads/2014/05/Close-up.jpg). The ISS would decay out of low Earth orbit in less than a decade due to air resistance if it were abandoned, but such a large structure farther away from Earth could easily last millennia or more. [Answer] 1. Like all real estate, location, location , location. You want a location that won't be hit by the next ice age nor seismic activity. Probably, building it far out in the mid-Pacific sea bed would be best, followed by the south central areas of Eurasia. 2. Skyscrapers are named after the top-most part of the mast of high sail clipper ships, so by definition, they should have a significant taller than wide outline. 3. The most industructable material known is [Zircon](https://en.wikipedia.org/wiki/Zircon) which is so incompressible and non-abrading that crystals survive multiple trips through the tectonic cycle, being sub-ducted, then spit back out as in lava or metamorphic rock and then repeating the whole thing hundreds of times. Only the radioisotopes inside them cause them to degrade. They're the primary means of dating in geology. If you coated everything in the skyscraper with few millimeters of artificial Zircon, nothing would abrade, erode or catch fire. I don't know if the Zircon is itself structurally strong enough to make an entire structure with (the existing crystals are measured in millimeters) but if so, that would solve you're entire problem. More likely, it will just be an indestructible coating 4. Lighting is the major threat to skyscrapers. The "lightening rods" in them are actually huge systems of spikes, conductive wire, redundant systems and some seriously deep grounding spikes. You'd likely need a very tough standard temperature superconductor to handle the lighting. 5. But probably in the end, you'll need some kind of dynamic entropic flow structure, one that it held up by a constant energy flow that increases entropy so the 2nd law holds it together (that's how life on earth works). So, a very deep, geothermal system spreading for kilometers down and around the structure would provide the constant energy flow from the heat of the earth out into space. Diamond is the best thermal conductor BTW. Simple thermoelectric generators made of wires woven in through the structure from the tap root to the tip-top would convert the constant flow of heat, into a flow of current, which by the positioning of the wires, produce a constant repelling force, like a stack of electro-magnets that make a tower. If you had high temperature super-conductor, the magnets would be very strong and need only a trickle feed to produce magnetic fields for thousands of years. The magnets could be arraigned such that they repelled up and down but attracted in and out. If the structure did take damage e.g. a meteorite, the damaged pieces would be pulled back into a supporting configuration. (This based on a concept of space elevator some NASA guys works out some years ago.) 6. We're talking lots of power here. The skyscrapper's other structural material would act more like a rope holding the thing down that supporting against gravity. As such it could be made from almost anything not strongly magnetic e.g. titanium, which is functionally immortal itself. Lighter than aluminum, stronger than steel, doesn't corrode nor electro weld. If you could control the lighting, you could probably make the sky scrapper out of it. 7. You could even go the other way completely and make it an abandoned space elevator. A lot of the same techniques I mentioned above but since the thing will be a big cable with a mass stretching it out in space, things like earthquakes or gravitational collapse would cease to be a problem. [Answer] *Could* we build a skyscraper to last 10,000 years with no maintenance? Probably. See <http://longnow.org/clock/> for a related project that's really kind of cool. Casting skyscrapers out of molten rock (basalt might be a good choice, it's pretty durable) or similar techniques would have a lot of potential. *Will* we build such structures in any significant quantity? Doubtful -- they're expensive and our current structural needs tend to be obsolete long before the buildings wear out. You'd have to have a reason to want that kind of longevity before you started. Long-lasting materials are harder to work with and more expensive than what we tend to use, and we have no reason to use them in most cases since, if there's nobody to do maintenance, there's also nobody to care if the building falls down. That said, in another 30-50 years, we might well have buildings that could last forever. Not because they'd need no maintenance, but because our robotics technology is advancing rapidly. If it becomes common for maintenance of skyscrapers to be handled entirely by robots, and if the maintenance of the robots can likewise be handled by robots, then the only limiting factor to the building's lifespan would be cataclysmic events that exceed its structural specifications, and the stockpile of energy and materials the robots have to work with. The skyscrapers most likely to survive would be the manufacturing plants where robot parts are made, since they'd (potentially) have a ready supply of raw materials and the tools needed to convert them into maintenance drones. If the build orders got cut off, it's conceivable that the remaining material stockpile would be sufficient to perform basic maintenance for a very long time. If the robots are networked and capable of finding new sources of raw materials on their own, whole cities might survive for millennia as well. [Answer] # Build a bunker. I'm talking cold-war-era-like, 20-stories-underground bunkers with included vertical missile silos. Why bunkers are good candidates: * These things are built to last, and to withstand enormous amounts of damage while keeping structurally sound. * Unlike residential or commercial skyscrapers, bunkers are built with resistant materials. You can assume that state-of-the-art five-meter-thick nanolathed concrete will be used. * They have both livable areas with low ceilings and awe-inspiring 100-meter-high vertical silos. * If you assume a high-tech cold-war setting, then the military powers could build hundreds, even *thousands* of these things, and spend tons of R&D on making them lasting. Why bunkers are bad candidates: * They are underground, so they're not visible, so they're not awe-inspiring. D'oh. > > Sometime after, there is some kind of cataclysm (haven't worked out an appropriate one yet). > > > Well, there's your answer to the problem of bunkers being underground. If you were to have a big flood, or any other kind of environmental event that *erodes away the soft soil around the bunker*, then the structures would just appear. Granted, the structural integrity of an underground bunker is provided by the earth/rock/soil around it. But if you assume that the warmongers built a dozen hundred silo bunkers, it's plausible that just a few of them were built in a place where the erosion would leave them standing. [Answer] At first, I wanted to recommend artificial diamond, but after reading some comments (basically saying that it's too fragile) I thought why not use some other huge molecule (probably mostly out of carbon)? Another option would be to use something similar to natural rock, but have some sort of living creature on the surface to help repair damaged parts. An example would shellfish, that's shell (very slowly) decomposes into chalk/limestone (the time-scale would not make it an ideal building material). EDIT(from comments): You would have a possibly alive thing/very complex molecule/mixture of chemicals that is put under the outer layer of the building, and if that layer is damaged, it gets exposed to air and sunlight, and using something slightly similar to photosynthesis it turns them into the material (probably organic) that the outer layer is made of. The clever bit is that only the outer bit is exposed to all the needed ingredients, and so only that makes more material. [Answer] Build it as a single crystal diamond. It is possible. You can make small amounts of diamonds in your microwave using carbondioxide and hydrogen. It is a slow and an inefficient process. Since the whole structure deposited layer by layer (in atomic scale) it is much like an additive manufacturing (3D printing). Required construction time and energy is enermous today's standarts(I guess that's the semi futuristic part). But the final structure: **billion-carat-tower** will surely be inspiring... [Answer] Woven carbon nanotubes are an option. There is an international race currently to get their manufacturing costs down and I fully expect it used as a building material in the foreseeable future. There is even a proposal to build a massive air cleaning factory that sucks in CO2 and converts it into CNTs. <http://phys.org/news/2016-06-power-co2-emissions-carbon-nanotubes.html> CNTs are strong enough to be used in a space elevator so a "mere" skyscraper should last that long. Especially if it's built solidly, with that purpose in mind, using all of the best techniques and other special/new materials like the various ceramics with crazy properties. [Answer] I'm taking the unusual step of putting in a second answer because it is more than an edit of the existing answer and also building on some suggestions in the comments. Building a skyscraper or anything else on the Moon means a lifespan of millions of years as a recognizable artifact. Some comments mentioned building a "Great Wall of Luna", which would be both large enough to resist erosion by micrometers for eons *and* visible from Earth. While megalomaniac emperors throughout history have wanted to build monuments that last forever, few succeed. Building a mammoth wall on the Moon also seems a bit pointless, until I stumbled across [*this*](http://www.nextbigfuture.com/2011/12/friedlander-cold-crown-cold-trap-for.html). The *The Friedlander Cold Crown* is simply a giant circular wall surrounding the lunar pole (or poles) to create a shadowed area where gasses from lunar industry would condense and freeze, maintaining a very hard vacuum on the lunar surface. Even molecules of atomic oxygen moving across the lunar surface as a result of lunar mining or industrial processes would be fantastically corrosive and damaging to industrial and scientific equipment (imagine a massive lunar telescope who's mirror was pitted by corrosion due to oxygen venting). > > The takeout for this is oxygen (primary waste gas from lunar rock refining) can travel around the moon in around 47 hours (450 hops at 160 km each, taking 380 seconds between bounces) > > > The Cold Trap is a circular wall 40 kilometres tall that surrounds the poles, and any molecules of gas which fall into the trap radiate their energy away and do not get new energy from the Sun. From the Earth it may look a bit like this: [](https://i.stack.imgur.com/uFzrT.png) *The Friedlander Cold Crown* So we have a plausible reason to build a megastructure which is both visible from Earth, built in a "quiet" area devoid of most environmental issues and capable of resisting erosion for geological ages, most likely still large enough to be visible a billion years in the future when the Earth becomes too hot for water based life.... [Answer] I don't think I can make it to 10,000 years, but here is how I would try to make a long lived building that was usable. Let's make it the height of a clipper ships masts. Since power may be intermittent, call it 15 stories, Who wants to walk up an 80 story building? 160 feet, 50 meters. The steel frame is made of Corten steel or some equivalent. This when exposed to water forms a fixed layer of oxide that protects the rest of the steel from corrosion. Steel is not exposed, but is embedded in the concrete. We don't want a repeat of the Building 7 collapse from the building contents burning. Concrete rebar is also made of self limiting corrosion steel. Prolonged wet exposure won't cause the rebar to rust then crack the concrete. All floors have a slope to them so water exits the building at scuppers/spouts. (The building could look like it's studded with gargoyles. Windows have heavy lintels and are set back so that even a missing window results it little water ingress. Windows are made of synthetic sapphire. Building is clad with synthetic sapphire, done in overlapping shingles so that hte connecting mechanism is not exposed. This is the anti-abrasion layer. The cladding can be coloured by use of impurities. (ruby, blue sapphire...) Note: Potential problem of people stripping off this layer for ornamental use, much as the marble was stripped off the pyramids. For this reason, the cladding should not be polished but should be flat black at least at the lower levels. It may be possible to develop a sapphire solar cell for cladding the southern side of the upper floors to provide some interior power. It may be that a cladding of sapphire and carbon black would work better, both for expense and for shatter resistance. Being black, the building will be warmer than the environment. Harness this for passive stack ventilation. Initial interior would be open design broken by columns. This allows some use of the building even without power, and helps with ventilation. Over time, different groups would partition it differently, but partitions are regarded as furniture, not as the building proper. Wear surfaces are sapphire again. Floors are sapphire tiles set into concrete. Doors have aluminum or non-corrodable steel frames. Hinges and hinge connectors are engineered for 100 times a day use for 10,000 years. (In my years doing building maintenance, it's not the hinge that fails, but the fastening to the door or jamb. Automatic closers. Hmm. These have a definite life span. It may be better to make doors sliding doors on a sloped track so that gravity is responsible for closing the door. They could be jammed open, but would resume function when the jam is removed. Convention doors could be used wherever a non-auto closing door is needed. Utilities: I'm much less confident in 10,000 year life span. Our chem department at University had glass plumping from the lab sinks. You certainly win with corrosion resistance there, but joints were made with stainless steel clamps and some kind of gasket. Part of building longevity is to make the inner systems accessible. Ships are designed to be maintained. You see the bones as you walk through them. Houses are not. So wiring is in channels, not in the wall. Water supply is plastic, place where it won't be exposed to UV, and sized large enough that flow erosion is small. Valves. How do you build a dripless faucet that will last 10,000 years? Some longevity can be gained with redundant systems. Warships have a main power bus ring, and sometimes two on different levels. Breaking the ring at any one point still leaves power to the rest of the ring. Isolation breakers keep a shorted bus from taking out the whole bus. This mindset can be applied to plumbing and data too. [Answer] Give it some form of automated maintenance. Alternatively, an engineered species of lichen or coral-like organism could keep a mineral based structure in good repair and vastly extend its lifespan. Living things can repair the minor day to day damage that usually takes down large structures. Once they have some form of maintenance then all you need is fairly benign location and decent structural engineering. You could also use trees, redwoods actually form buttresses joining one tree to its neighbors. If they were engineered trees *some* of them surviving for tens of thousands of years is not out of the question. Imagine your explorers realizing the forest they are in is really a housing development. [Answer] If it's OK to repurpose rather than build from scratch, then it must be [tepui](https://en.wikipedia.org/wiki/Tepui) FTW. [Mount Roraima](https://en.wikipedia.org/wiki/Mount_Roraima) in particular: 2338m prominence (935 stories?), 31 km^2 flat summit area, and it's already about 2,000,000,000 years old. It even has caves. [Answer] 10.000 or 100.000 or 1 Million year old skyscraper would be no problem. Also wood could be possible for construction, if you renovate it in depending of the material qualities like Japanese Temple do since centuries, only made by wood without glass and without metals. The main thing will be, the social system, who care about your building. You will need a believe or in old words, a religions system, who care about themselves in a nice and harmonious way for your plan of 10.000 or 100.000 or the 1 Million year old building. Every plan begins with good idea and plan. The matrix and material for the building will not be the problem of first step. First find in your brain a human system who will carry your idea over centuries, to love your idea by the avatar of your building and run for you. They scientists in 1.000 or 100.000 or 1 Million, which will love your idea and your building, will always find the best way and materials for keep it proper and fresh, your building. Feed them by your first idea and they will run for you, as long your building will stay on earth. [Answer] I like where Rat In A Hat is going. As population increases and efforts like the International Space Station continue to succeed, I could see large scale apartment or business structures in Earth orbit. If Shock & Awe (tm) are what you are after, only one or two need to make landfall intact. In this scenario, building on Thucydides answer, we utilize the advantages of space for longevity. We also assume there are automatic safety measures in place for if the structure fell out of orbit to bring it back to the surface allowing the most survivors possible within and without. Whatever event reset life on earth, the supply line was cut and there is none left onboard. Depending on your story needs, they current Earth inhabitants either see it land, or discover one that has recently. [Answer] If you mean by without maintenance really means is without human maintenance: then how if you build a forever learning and adaptable ai that can maintain and update itself included in the structure. At first it can deploy a not far future drones to maintain the system and building and later can upgrade itself, learn and discover more technologies, even search and harvest materials it needed from the nature far after human had no longer existed. There's one beautiful story involving a structure like this as its 'main character' its a manga by Boichi <https://myanimelist.net/manga/2436/Hotel> [Answer] As mentionned, pyramids lasted very long mostly thanks to their shape. A tetrahedron is much better than a cube (skyscrapers). However it s not the optimal shape. Basically whenever you have edges, the edge will wear down faster then the other parts and thus will weaken the structure. The optimal shape is semi sphere. Any material like concrete will be fine. A semi spherical concrete bunker would probably last 10,000 years. After 10,000 years, wind/corrosion/rain will have worn it down and it ll look like a small rocky mound with probably some grass on it but it ll still be there. ]

[Question] [ **How would you design a piercing projectile (arrows, bullets, shurikens, etc) that can deliver a payload of malicious software to a computer that it is shot into?** Although it is rather silly and definitely very soft sci-fi, this is a type of weapon that shows up with surprising frequency (Avengers movies, XCOM games, etc). Essentially, this projectile weapon can hack a computer that it physically pierces through, immediately beginning the hack as soon as it becomes lodged inside the computer case proper. Perhaps the main concern is its interaction with the physical internal components of the system. By its very nature, it needs be in very close proximity to specific internal components in order to deliver the data payload, yet it also risks physically damaging those same components. Requiring direct contact between the weapon and the components would be impractical, so one would probably need a method that can transmit wirelessly over at least an inch or two. One must also consider which internal components would be interacted with. Different pieces of hardware speak different languages, so one might need to be prepared with multiple different types of viruses to hedge for which pieces of hardware can be reached. What might the optimal physical design of such a weapon be? I would imagine that a long, narrow arrowhead would be ideal for piercing the outer casing of a machine while minimizing internal damage. In order to be a proper "hacking arrow", the weapon **must avoid destroying or shutting down the system with physical damage**, at least immediately. There must be time for the software to be transferred and activated. The system might still break after some seconds or minutes due to mechanical issues or fire, and/or the software may destroy the system once it is finished, but the system must still temporarily survive being punctured. **What are the key aspects in designing a weapon that you can physically shoot into a computer in order to hack it?** [Answer] Don't try to get information into the computer. Computer hardware just doesn't work that way. You're going to have to rely on so much extreme handwaving that you might as well have had a wizard cast a spell on the computer to hack it. Short of Jason Bush's nanites approach, it's just a non-starter. Instead, try to get information *from* the computer. [Van Eck Phreaking](https://en.wikipedia.org/wiki/Van_Eck_phreaking) is a well studied approach to gleaning information off of a computer using side-band data captured electromagnetically. It can be done from across the room, or potentially even further. Few systems are designed against this, and almost all of them rely heavily on shielding which you could penetrate with your arrow. Once you have usernames and passwords, hack the computer like usual. [Answer] As this is a very unrealistic scenario I tried to think of any realistic answer that would handle all of the variables. My best response is that the projectile would pierce the case of a computer merely as a delivery platform for specialized nanites, programmed to form virtual networks and launch various penetration attempts against the system and its components. It's possible that the projectile could serve other functions as well, such as providing a wireless power source for the ninites, or providing a wireless communications channel through a shielded computer case. How much of this could be accomplished with existing technology I do not know, and there are likely more useful methods for accomplishing such things (see social engineering). [Answer] This requires a bit of setup, but I think it works. Early in the story, have engineers discuss that the new computer architecture really isn't all that fault tolerant. If anything goes wrong, it pretty much has one fail mode: brick (do nothing). Even non-critical systems trigger the fail mode. The exception is when there's a debugger attached by wireless communication, which allows tech support to diagnose the issue and do things like upload driver patches. I've seen some devices that work like this. Having a full computer work that way is improbable, but an embedded computer, like a bridge/dam monitor would be unsurprising for me. Later, your hardware assassin (HA) creates a gun like a nail gun, with a payload. I'm thinking something like one of those toy rockets from the 1950s with the super sharp points on the tip, without the fins. The body of the rocket has wireless device in it, like a Raspberry Pi. HA fires the nail gun at the target computer, aiming to hit an unused USB port. Puncturing the port may create a device error since those ports are polled regularly for a connection. That's the only non-critical system I can come up with that is targetable and active, particularly on the embedded targets I mentioned earlier. HA probably has a short range of a few feet. The target goes into fault mode. The wireless in the rocket body opens communication and says, "Hi. I'm a debugger. I'm here to help you." It proceeds to patch, likely with admin access, critical code. And then it does whatever it needs to do. This idea skirts the edge of believability, I admit, but perhaps it is a shell you can build from. [Answer] It may not be as silly as you think. [Sound based](https://en.wikipedia.org/wiki/Acoustic_cryptanalysis) attacks on encryption have been demonstrated, and other processing tasks might leak other data. [Observation](https://www.wired.com/2015/06/radio-bug-can-steal-laptop-crypto-keys-fits-inside-pita/) and potentially control of signals on wires is possible at short ranges. Some chips are now using wireless communication to avoid issues with moving low power high speed data over small wires. Getting inside the case would make these less silly-sounding even though you don't need to with the real world attacks. The hacking part probably needs to be targeted to a device, so the projectile might be too. Either using cameras and control surfaces to aim itself at a known safe spot in the case, or maybe having a well designed shaped charge that opens a hole without throwing around much extra energy to damage things and a soft part of the projectile going in at a reasonable speed. Redundancy and failsafe are expected to be words computer users like to hear for the foreseeable future. High end systems (specially the ones that might be expected to get hit by things) try to still work when some damage is done, quite possibly by switching to identical backup parts in the same or a nearby box. [Answer] I can think of a couple, admittedly far fetched, scenarios where a "hacking arrow" might be useful. 1. PCs are protected by a faraday cage. So the arrow head pierces the case in order to breach the cage and be able to wirelessly interact with the sensitive non-hardened components inside. This would presume that PCs rely almost exclusively on the cage for protection from remote hacking, once you breech the cage it is easy to hack the PC with a Bluetooth, NFC, or Wi-Fi transmitter. 2. The arrowhead is cutting a CABLE, essentially bridging the gap and allowing a microcomputer inside the arrow head to read all the data being transmitted by the cable and insert it's own code. So imagine a data cable that is being physically severed but the arrowhead still passes info to each severed end. Upstream and downstream PCs may not notice a difference (perhaps slight lag?). Of course this can be done in the real world and doesn't even need to physically cut the cable. Obviously extraordinary marksmanship would be required. 3. The arrow head has a powerful transmitter that needs to be very close to the target in order to overpower electronic countermeasures/jamming. Sure, the building may be secure from intruding transmissions, but if you could deliver a transmitter RIGHT NEXT to the target, it could cut through the interference and "hack" the target. [Answer] # Solid Snake Why not have the shaft of the arrow contain a snake-like robot which finds and plugs itself into any unused [1394/USB headers](http://www.computerhope.com/jargon/u/usbhead.htm) on the mother board. The tip of the snake is therefore just the header with a wire to the base of the shaft where the controller sits with a small camera for identifying the pattern. At that point you have physical access and unless the computer admin has taken specific action to disable the unused header, you basically own most computers. The shaft also contains batteries (until it can charge from USB) and acts as an antenna for wireless transmission. [Answer] Earlier I posted this answer: <https://worldbuilding.stackexchange.com/a/69310/26246> I claimed it was a bit unrealistic... well, here's the details... *(I thought about editing my earlier answer, but I'm going to go into way more detail here... best to start with a clean slate so the comments aren't confusing.)* I will mark certain words in **boldface**. Those are the points of this description that are particularly relevant to answering this question. --- This is computer. It is a ruggedized cRIO-9032 from National Instruments ([specs here](http://sine.ni.com/nips/cds/view/p/lang/en/nid/213602)): [](https://i.stack.imgur.com/lIuBb.png) It is designed for **outdoor use**, primarily as a monitoring and control system for things like stress on bridges, gates on dams, stability of volcanoes, etc. It is **wi-fi enabled**, and operates in environments ranging between −20 °C and 55 °C. [The chassis is **aluminum A**.](http://digital.ni.com/public.nsf/allkb/8171B88F5942E90A86257346007CB77A) Now... you see those four rectangles on the right side of the image? Those are cRIO modules — think like a card on the inside of desktop machines, but these add various external connections for sensors and whatnot. Here's a closer view of one module: [](https://i.stack.imgur.com/OGSBx.png) R&D testing confirms that **you can destroy one or more of those modules** — as long as the backplane isn't pierced, the computer will continue running just fine. The next time that the computer tries to access that module, it will raise a "module not found" error (error code −65622). The backplane is pretty easy to miss — **an arrow vertical through a module won't hit it.** Now... I said this is a computer. A user programs it with whatever software they want, running on the real-time operating system. **A brand new cRIO has "admin" and blank password as its default setting.** Users are responsible for configuring a better password. ## What does all this mean? * It means you have a computer that is frequently deployed in outdoor locations where it makes sense to shoot an arrow (unlike a server room). * You have a system with that will continue operating if a part gets destroyed. * And you have it programmable to be as secure or unsecure as the software engineers who work on the project choose to make it. ## So now the scenario goes like this: A team of software engineers creates some sort of monitoring system. They're pressed for time, and they know that they're going to have to debug the system later in the field, so they leave their debug backdoor in the software — it's off by default, but if one of the modules turns out to be buggy, the wi-fi will open an unsecure port so a laptop can log in an provide instructions. They aren't worried about security because, well, let's face it, few software engineers are, but this team figures they're out in the boonies, monitoring an oil rig or something. What they forget is that this device, in order to upload its regular monitoring data, has login certificates for databases that should probably be on an air-gapped system away from anything sensitive, but probably aren't because, again, no one worries about security. So instead, those databases are hosted on server X. So your hacker needs to get into server X and learns about this remote monitoring project. The cRIO is high up on the oil derrick. And the hacker has one of those [nifty arrows from Hawkeye of Marvel Comics](http://marvel.wikia.com/wiki/Trick_Arrows/Gallery). This particular arrow has a payload behind it of something like a Raspberry Pi or similar device, nicely form-factored for aerodynamic flight. (Don't complain about the handwave — I got the answer to this point... you're on your own for arrow design!) He/she goes out to the site, fires his arrow with its electronic payload through one of the sensor modules. The cRIO raises the error code, and the silly developers' debug code turns on the wi-fi. The arrow logs in and uploads new instructions, takes advantage of security certificate for server X. He/she then goes home to his [7-monitor desktop system for some serious hacking](https://hardforum.com/threads/thoughts-about-the-multi-display-set-from-the-movie-swordfish.1107929/). (Please don't do this in your movie. Stupid Swordfish.) **Important: If you ever make a movie using this idea, my co-workers are very intrigued and want to be notified!** [Answer] Like most of the answers, this requires some handwaving: Let's assume your target computer is connected to a standard keyboard by an [unshielded](https://en.wikipedia.org/wiki/Shielded_cable) wire. You fire your hacking arrow into the keyboard (or maybe at the wire itself). It outputs an electromagnetic signal powerful enough to cause interference in the unshielded wire, generating signals that get sent along the wire into the computer. If your keyboard uses a standard protocol, then the hacking device can output signals that get transmitted along the wire and emulate keystrokes. Now your arrow can 'type' input into the target system. If the operating system is known, you come up with a standard set of keyboard commands that should perform a specific action on the target machine, such as (on Windows) ``` [windows key] + [R] //opens 'run' dialog [c][m][d] [return] //opens command prompt [e][r][a][s][e][ ][c][:][\][w][i][n][d][o][w][s][\][*][.][*] [return] [y] //confirm operation ``` [Answer] I don't think that a piercing projectile can be of any use here, maybe something sticky that glues itself to computer device, melts a hole and sends in nanobots or something like that. Just think for a second about shooting a metal box with an arrow. In order to pierce you need to shoot at a certain angle, with great power and there are also many other things you need to consider before getting to the data transfer problem, because in reality arrows are by far not the best projectiles. If you really want a projectile that pierces I'd go with a bullet, but again, what if you damage some physical connections that are in the device and won't be able to transfer data? Or damage the components that store data, or short circuit will happen and instead of any hacking it will just burn the device. Too many possibilities for a bad ending. It's unpractical. Generally speaking, if such thing was possible, it would exist in our world by now. To answer your question we need more information about the level of computer technology that exists in your world. It's like the current level of tech on Earth, then it's impossible to have hacking bullets. You mentioned XCOM series, but I don't remember anything like that there, beside hacking with a flying robot that connects to something, maybe you mean EMP grenades? Though it's not hacking. [Answer] Does it have to actually pierce the computer, instead of just sticking to the side? If it can just stick to the side (thus not damaging anything), the arrow could use powerful antennas and hyper-advanced beamforming techniques to induce currents in specific parts of the circuitry, thus changing the data as desired. Given that almost all computers have little space between the components and the case (even a desktop tower doesn't, on its right side), I think the best approach would be to stick to the side with an instant adhesive. The metal case would be the greatest issue, as it interferes with the electromagnetic hacking, but you can probably write it off as a problem solved by the hyper-advanced beamforming. Edit: As for the instant adhesive, it could work like how Post-Its work, by having zillions of tiny glue bubbles that are popped on contact, causing them to stick. Of course, something stronger than Post-It glue will be required. [Answer] Bridging the air gap First why are you shooting projectiles to hack? Well it must mean that you have limited / no access to the system and you are using this odd tool to open a new attack vector. The simple version of this is an air gapped or firewalled system. It is also true that some newer operating systems offer different authentication methods for a local user rather than remote (camera authentication is now available) these might be easier to attack then the modes accessible through the internet. How does the projectile interface with the machine? This is the hard part computer parts and ports tend to be small enough so a miss by more than a millimeter will make the system fail. So you need to be freakishly accurate but also "hit" lightly enough to not damage the port or component you are attaching to. The first idea that springs to mind is to have a frame the pads the landing and attaches to the outside of machine the frame then detects the location of the port (usb or whatever you desire) and connect to it. This gives you a stationary and stable platform to preform the delicate connection. The added weight of the frame and the high accuracy requirement make this a better candidate for launch by computer sighted launcher than a human archer ... unless the archer has the super ability of ludicrous accuracy. [Answer] Mentioning this since I don't see it already. # The projectile doesn't hack, it just locates the computer So, imagine someone like Tony Stark. He's already got access to any machine in the world he wants through his sophisticated mainframe. The problem is identifying that specific computer over there. The projectile projects a carrier frequency physically into the hardware that can be detected on the global internet so the super-computer can find it and break in from the outside. [Answer] I saw this while I was over on the StackOverflow forum and I just had to come and write a response. I would say that no, computer hacking with an arrow is actually relatively feasible. Just consider your standard organization; they usually have security personnel who align all of the wireless antenna to function solely within the building. If you are a hacker, and a half decent bowman, it would be much simpler to fire an arrow in an open window than to try to sneak past mantraps, turnstiles, and that guy named Joe who mans the front desk with some sort of weapon (Probably an axe). Then, suddenly, you can use the arrow as basically an altered Wifi range extender allowing you to access their network from your car outside the premises. This is what is known as a rogue access point. Of course, usually it would be easier to simply use phishing or DNS hijacking to get into the network, but assuming your targets do not have email addresses or a webserver and their OS is fully patched, this arrow might offer a way in. Secondly, I agree with those who say that you could cut a cord with extraordinary marksmanship and use it as a Man-in-the-middle tool, in which you could capture and alter packets as they flow through and use them for all sorts of things such as: Stealing passwords, credit card numbers, and other personally identifiable information. Of course there is more than that, but that is up to you to figure out. Lastly, please let me introduce you to a technique known as [Rowhammer](https://googleprojectzero.blogspot.com/2015/03/exploiting-dram-rowhammer-bug-to-gain.html). This technique normally exploits the tendency of bits to flip within memory when a nearby bit is electrically discharged. Normally, it would be utilized within a web-exploit, but in your case, it is much simpler than that. Just apply direct electrical discharges to any part of the memory you want to change, and the behavior of the computer will change accordingly. However, this requires access to an extremely similar system beforehand on which to test it, as there is no way you can perform this attack without prior knowledge of the system's configuration, as you will destroy the machine. That's it for now, but of course, there are more options than just the three I presented here. [Answer] Well this answer admittedly doesn't answer the question as is because it doesn't fit many of the requirements. But I think it is a bit more realistic so could be of use for ideas. [Frozen RAM bypasses all disk encryption methods](http://www.zdnet.com/article/cryogenically-frozen-ram-bypasses-all-disk-encryption-methods/) Encrypting a hard drive can be a great way to ensure data stored on a computer is safe. To access this data you type in a password and it is stored in RAM so that the computer can continue to read/write to memory. This is considered safe because RAM is volatile so no one can come in and read that password out of memory. However, it has been shown that if you greatly reduce the temperature (freeze) RAM it drains its memory much much slower, thus giving an attacker time to plug the memory into their own machine and read the encryption key. So, if you want to work this into a story, you can detail a room with top secret encrypted computers. The hacker has devised a way to gain access to the room but as soon as he does an alarm will trigger locking down everything and shutting down the computer. To combat this, before entering the hacker shoots an arrow into the computer which then delivers a payload of liquid nitrogen. He then enters the room, grabs the frozen RAM and encrypted hard drive, and makes off with all the tools needed to get to the secrets. Not as flashy as remote downloading arrows like in the avengers but real life never is. [Answer] You're definitely getting into the fictional realm of science fiction here, but let's examine the variety of computer bits that you *could* hack, and some of the reasons that might (or probably wouldn't) work. I think I'll go from hardest/most valuable to easiest/least valuable. # Processor/Motherboard/BIOS The most valuable target in your computer is the processor. If you could actually capture the signals that are going in and out of the CPU, you could potentially setup an emulator to replay the data. Additionally, you could inject your own signals into the stream (bonus points if you can sever the traces on the mother board and become a Man in the Middle (MitM)). Then you could alter the signals however you want. Other points on the motherboard offer you similar kinds of benefits, like the RAM. The problem, of course, is that you're talking about teeny tiny traces. Also, sensitive voltages. It's pretty likely that you'll crash the system when you try this. But you *could* do it. If you can overwrite the BIOS with your own, however, you've also taken over the system. Though a lot of newer systems actually have certificates baked into the hardware, so monitoring would be a better thing here. # Disk drives You can pretty much apply the same principles to disk drives - monitoring and injecting. The trickier business with the hard disk is that it's likely for a high-value target that by the time the bits make it to the disk they've been encrypted by the OS that's running in RAM. # Ports You could probably reasonably develop a system with current technology that would allow you to fire darts into unused ports. Naturally they can't be blocked, but you could do something to that effect. Or perhaps your hacking tool has the mechanics to unplug something and then become a MitM. Probably one of the most effective usages here would be attacking an airgapped target. Of course the unfortunate (for your attacker) thing about an airgapped target is that it's probably going to be pretty obvious that it's being attacked. # External devices Depending on the circumstances and the device there may be an opportunity to attack external devices. Keyboards are probably the *most* valuable. For network cards, again by the time the information reaches the card it's probably going to be encrypted - especially in a high-value target. [Answer] ## Pierce and Play So this is going to be a b it of a stretch, but bear with me. To start with we need to think of the projectile as two parts; the inside is going to be a high-tech computer of sorts, and the outside will be an incredibly strong and well-designed conductor. ## The Shell This is the part that is going to be hardest to swallow, but I'll give it the old college try. The outer surface of your projectile needs to be made of some kind of super conductive material. The idea is that after you physically insert it into the system that you are trying to hack, it will be able to essentially replace whatever bits of the original architecture it displaced with itself. Data is really just electricity moving around, so if your projectile can continue to move that electricity in the same way as the original hardware it shouldn't be a huge interruption to the computer. Of course, for this to work out you are going to want your projectile to be incredibly sharp and as small as possible, to destroy the least amount of physical hardware. Something like a crazy high tech dart might be the best option for this. ## The Guts The inside of the projectile is just as fantastic and unlikely, because what you need is a computer that can figure out what kind of data is being sent through the projectile and then alter it in some way. Think of it like a man in the middle attack, only the man is actually an arrow (or dart, or whatever) and what he is in the middle of is your computer. ## Handwaving at the Highest Level So, lets pretend that you have this kind of projectile and go to use it. You throw a dart at the target computer, it pierces into it and begins acting as a conductor for the physical parts of the computer that it just destroyed. The onboard computer analyzes the data that is passing through the projectile and then alters it in whatever way it is programmed to. Eventually this leads to the targeted computer getting "hacked" for whatever definition you want to use. Once you are done you can remove the projectile, which will break that connection and kill the computer it was shot at. [Answer] Make up computers vulnerable to such attacks but resistant to physical damage: Our present day computers are very likely to crash if you broke their casing and start fingering their tiny parts. But take the human brain for example: It is much more sensitive to many factors, for example pH change or temperature, but can endure quite a much localized damage without shutting down and even learn to substitute the damaged parts. Make a computer which has many independent but connected physical parts processing information simultaneously. (Not a classic computer build around a processor and running a neural network, but real, hardware based artificial neurons.) Such a device won't be used as PC or data storage, but to control something (robot, drone swarm...) which has to intelligently react to it's environment. If you breach it's casing and wipe out some thousands neurons, it won't wreck, but will start to adapt to the situation and reroute its computing to unharmed parts. But your projectile will connect to the places of the broken neurons and send in false information. If you know enough about the system you hit, it may will be able to take control over the device. [Answer] I think hacker arrows make sense with one condition: # The computers have hardware backdoors, either by poor design or sabotage Say that the computers have hardware installed that can open or shut a programmatic backdoor (an obviously bad idea, but a [surprisingly common one](https://en.wikipedia.org/wiki/Hardware_backdoor#Examples)). Or maybe you know a rebel scientist who works in chip manufacturing and has created [hidden backdoors](http://www.computerworld.com/article/3079417/security/researchers-built-devious-undetectable-hardware-level-backdoor-in-computer-chips.html). If you can fry that hardware the right way you'll open the backdoor. Once the backdoor is popped via hacking arrow, the device is ready to be hacked remotely by our archer's hacker compadre. What does "fry" mean? I don't know, ask the rebel scientist / hacker compadre. Hell, they probably designed the arrows. But maybe it means something like [wireless capacitor charging](https://www.google.com/search?q=wireless%20capacitor%20charging)... > > In June 2016 it was reported that University of Michigan Department of Electrical Engineering and Computer Science built a hardware backdoor that leverages "analog circuits to create a hardware attack" so that after the **capacitors store up enough electricity to be fully charged**, it would be switched on, to give an attacker complete access to whatever system or device − such as a PC − that contains the backdoored chip. In the study that won the "best paper" award at at IEEE Symposium on Privacy and Security they also note that microscopic hardware backdoor wouldn't be caught by practically any modern method of hardware security analysis, and could be planted by a single employee of a chip factory. > > > <https://en.wikipedia.org/wiki/Hardware_backdoor#Examples> [Answer] Let's look at modern day Bluetooth. The protocol is not very secure. It's encrypt ions are not high grade. Bluetooth depends on one thing, for someone to hack you they would need to stand uncomfortably close to you for a long period of time. That's not a real scenario. So in modern day people talk about constructing large super targeted Bluetooth antennas. They can then interface with Bluetooth from a mile away and the hack becomes a real threat. So back to the arrow. The idea of the arrow is to attack an NFC interface (near field). For instance something that works only one inch away, and is constantly observed by security may be very insecure. Plant an arrow on the other side of the wall that would give you radio access to the NFC and now you can quickly hack the weakest point in the security network. [Answer] So this is a way out there... but considering the examples all come from soft sci-fi sources maybe it'll be ok. So first the head of the arrow needs to be able to pierce thin steel, but not penetrate too deep, so a sharp hard point with arms coming out the side to let just the tip in, and keep it from going right through to the sensitive stuff. Behind the head and maybe up into the shaft of the arrow would be electronics, with a bunch of little super thin wires that would extend, seek out and tap into key areas like the ram connections, processor, hard drive, etc. [Answer] At the risk of stating the obvious, you could just have an arrow with an RJ45 plug on the end and a small single-board computer glued to the shaft. Shoot it into an unoccupied ethernet port on the front of a rack-mounted server and it connects via (say) an unsecured heartbeat network and uses some exploit to pwn the server in whatever way the story requires. As to why you need the arrow, it's not unusual for servers to be in locked cages or for sections of data centers to be separated by welded mesh security fences (allowing servers to share airflow while keeping customers away from each other's equipment). Hitting an RJ45 would require impressive, but not inconceivable archery skill; I assume any character doing this is meant to be a bad-ass. If you just want to shoot an arrow with flashing lights into a server and then say it's been hacked, "something something van Eck phreaking" would cover it, but I would say that is phenomenally difficult to sell if you are going into a lot of detail. Modern computers are filled with GHz-frequency components and spinning fans and bits of metal that would make it difficult even in a lab setting. [Answer] I believe that this is possible, and it can be even more discreet/fast than you think. You state that the required "software" is set up and that is needed in my idea. Say you have a RFID scanner setup. Then you shoot an arrow with an RFID chip inside that has your hacking codes or whatever into the computer/receiver. If the RFID scanner continues to be able to actaully pick up the signal you send it will activate the commadns you sent. Now probably if you want it to look like it "hit" the machine, then make the computer and arow head magnetic. That way, hopefully with no penertration, the info is delviered. Better yet, you could just have the arrow with the information whiz above the reciver and delvier the commands. [Answer] After penetrating the outer shell you could use tendrils that are attracted to any electrical connection that hijack the signal and replace it with their own. This would allow you to read for eg. the cpu traffic, figure out what it's doing and then start controlling it. I would suggest the arrow has wlan that it uses to connect to a sophisticated data center somewhere that can quickly analyze the caught traffic, scans every connected device for information and then starts controlling it if it's already known. If it is unknown the programms used get transmitted to the datacenter and analysed for function names/common patterns that give information about the programm, those are used by an AI to reverse-engineer the programm and then control the device used. The tendrils could be from a specially engineerd tin alloy. Based on the real world phenomenon of tin wiskers which grow slowly in electronics and shortcurcuit it. <https://en.wikipedia.org/wiki/Whisker_(metallurgy)> The german article names Antimon, Cadmium, Indium, Tin und Zinc as metalls which form whiskers. [Answer] This is C.H.I.P.: [](https://i.stack.imgur.com/pMsbk.png) It has: > > 1.0GHz CPU > > 512MB of RAM > > 4GB of storage > > Built-in Wi-Fi and Bluetooth > > > I am not saying this has to be done with C.H.I.P., but rather suggesting that since it has these specs, then something smaller might also have enough hardware power to connect to a wi-fi network or [piconet](https://en.wikipedia.org/wiki/Piconet) and deliver a payload. And if [802.11p](https://en.wikipedia.org/wiki/IEEE_802.11p) ever becomes mainstream, you could also get into vehicular networks. Anyway. You need to get into a wireless network first. For ultra-realism, refer to: [Is hacking Wi-Fi THAT easy? (just spoof, and it's hacked?)](https://security.stackexchange.com/q/137104/49199) Otherwise, having people hack into systems as easily as walking into a bar requires a negligible amount of suspension of disbelief. Once inside, taylor the amount of technical terms to your needs. Again, for realism, you can say that a hacker exploited a zero-day vulnerability on a port to gain system level access and set a rootkit. If your audience is not composed mostly of techies or if you wish the tech to sound alien/super advanced, you can lower the threshold and just say that the hack "bypassed the buffers and sabotaged the relay matrix". The arrow in this case is just really the medium to get a malicious device close enough to your target. You don't even have to hit the computer proper. And if you are close enough, you can pull the hacking device out of the arrow and maybe stick it under a table with chewed bubble gum. And of course, if you can deliver it with an arrow, you might also be able to come up with solutions involving anything from nerf guns to potato guns. [Answer] **All the parts of the machine are wireless** Most robots are operated with wires connected to a computer, but it doesn't need to be this way. If your robot is going to be taking damage, the wiring is a weak point, since a cut wire can disable the robot. As an alternative, parts of the machine can communicate to each other via wireless (like bluetooth). Your projectiles could work by: **Jamming the signals** The projectile broadcasts a powerful signal on the same frequency as the wireless, preventing the parts of the machine from receiving signals. **Decrypting the packets and issuing new commands** This is a little less plausible, since encryption is hard to break and very easy to upgrade, but if your projectile can read the packets and transmit them back to a server, that server could get going on cracking the encryption. Once cracked, the projectile could pretend to be a part of the machine and issue new commands. [Answer] With known systems and technology, I think the shooter should target the parts of a system that can be swapped while the system is running, and not attempt to break/wirelessly control components that cannot be hot-swapped if the system must keep running, because the latter would take advanced mini robots to precisely place tiny connections, at least. Wireless control of any component with the size constraint of a projectile is rather unlikely unless there are known wireless vulnerabilities, though that may be viable if you know a way to wirelessly hack the system, but the security doesn't allow anyone to set up any wireless device anywhere near it - then shooting a wireless device there might be useful, but I wonder why the security doesn't just disable the wireless receiving component beforehand in that case. Shooting a small robot that can pierce into a network cable to decode and intercept the signals is probably easier, but if the shot must be aimed at the case, how about specific parts of a case like network/keyboard/mouse ports? Secure systems could monitor those connections, but you could imagine a determined hacker to have broken those protocols beforehand. After all, even the best computers can occasionally have a loose keyboard connection, right? ]

[Question] [ Lightsabers are really, really different from modern swords. They have weightless blades, will cut through their targets independent of velocity, and can be turned on and off fairly quickly. In light of these differences, it seems silly to expect battles between two masters of the weapon to resemble duels between swordsmen of earth. It seems even sillier to expect them to resemble Hollywood sword fights full of clashing blades, kicks, flips, and villainous monologues. Given the differences between them and swords, what would be the best way to duel with a pair of standard Star Wars-physics lightsabers? [](https://i.stack.imgur.com/aaAIK.jpg) (source: [nocookie.net](https://vignette4.wikia.nocookie.net/starwars/images/a/ab/EGTF-Cover.jpg)) *Probably not like this.* [Answer] *I have thought about Jedi duels a long time. I may have obsessed a wee bit much in this answer.* In the Star Wars universe, only Jedi and Sith use lightsabers as weapons because they're just too dangerous to use unless you have some level of prescience from your attunement with the force. Only a handful of individuals are known to wield a lightsaber without force attunement, and those who did so in combat did not last long (see General Greivous). **Accordingly, I will presume your fighters have some Jedi like skillsets to avoid killing themselves by mistake.** Jedi and Sith alike are known for their long game. The Jedi order sought to maintain balance for thousands of years. Darth Sideous had the gumption to fight two sides of a war for years before assuming ownership of the winning side. A Jedi or Sith will leave nothing to chance. Accordingly, we can rely on them to never act in a way which can perceptibly increase their chance of losing their long term goal. You won't see a Jedi or Sith make an attack that has a 95% chance of killing the other person and a 5% chance of getting stabbed themselves (unless killing that person *is* their long term goal or their long term goal can be achieved after death). Allowing random external influences to negatively affect their long term goals just isn't in their nature. **Jedi and Sith trust the force, not dice.** Instead, they will put themselves in positions which make their odds look more and more likely until they are convinced they have a 100% chance of achieving their long term goal -- and if that involves killing the other person, they will. The force does not give perfect information, or if it does, it requires a perfect person to listen to it fully. So let's set some ground rules for what a force-aware person can sense. **We note that Jedi can deflect blaster bolts, which suggests that they can be aware of the physical state of their opponent.** Whether it's the position of an ankle joint, or the direction of a blaster, they're likely aware of all of it. However, intent is trickier. It is noted that Jedi mind tricks only work on the weak minded. Canon Star Wars doesn't specify what this means, so I'll define it in a way which is convenient for talking about combat as a game. I will define "intent" to be a plan to control a state, such as the physical state of the opponent. For instance, if you have the intent to punch someone, that intent will guide the muscle contractions required to develop a high velocity in your fist (the physical state) towards them. This concept of intent is recursive: we can have an meta-intent shaping intent. For instance, you could have an meta-intent to win the fight, which shapes the intent to punch someone, which shapes the muscle movements needed to strike. **A strong minded individual will be defined to be one with many layers of intent, like an onion, or one with very sharp and focused intent. A weak minded individual will be defined to be one with few weakly focused intents. Jedi and Sith are limited in the number of layers of awareness they can pierce, and by the sharpness of those layers.** This is perhaps contrived, but it does line up well with the canon. If Obi Wan is sufficiently attuned to the force to be aware of all the layers of intent in the mind of a Storm Trooper, he can identify the exact set of motions which will exploit a weakness in that storm trooper's mind. If the storm trooper had a stronger mind, he'd have been unable to do so because a higher level of intent (which he is insufficiently aware of to influence) will catch his Jedi mind trick, and "correct" it. Alternatively, consider Watto, who clearly doesn't have many layers. He may not have many layers, but the layers he has describe very clear intent (to make money, mostly), so its hard to find a way to influence him without being detected. (I'd theorize that Qui Gon could have completely dominated Watto's mind, wiping all intent, but that'd be against the ways of the Light Side). --- Wow, it takes a lot of setup to explain a light saber duel, but we have all of the ground rules in place. Both parties are defined to be "strong minds," so they have many layers of intent. The game is *technically* decided by the physical state of the world (first to put a lightsaber through the other without dying, themselves, wins), but that game is played with "perfect knowledge." Both parties know the exact limits of motion for every joint. Both parties have an onion like set of layers of intents. The inner layers are inaccessible to the other (strong minds), but the outer layers may be suggested to by acting in a way which encourages those layers into a suggestible position. The Jedi will attempt to move in ways which suggest the Sith no longer oppose the Jedi's true goals, and vice versa (which tends to involve a lightsaber burn, but doesn't have to -- see the end of Return of the Jedi!). **Each party may act in a way which makes a very obvious suggestion (which is powerful, but easily detected and corrected for) or a very subtle suggestion (which is less powerful, but much harder to uproot). These suggestions can be done at outer layers (where it's easy, so obvious suggestions are fair game) or inner layers (where it's much harder to influence, so subtle suggestions will dominate).** **Game theory suggests how to play this game.** If you can find an outer layer for which an obvious suggestion is sufficient to permit you to not-loose, take it. This happens all the time when facing Storm Troopers - all you have to do is move in a way which encourages them to miss all the time. However, a Jedi or Sith who has such weakness is a very weak force-aware indeed. The force should have warned you about such weaknesses long ago. Accordingly, any weakness you see in early combat is likely a trap designed to catch the less enlightened. If you try for the easy victory, influencing the "trapped" chink in their armor, the motion you used to influence it may spell your undoing, as they influence you more subtly, preventing you from causing them to lose. Jedi and Sith battles focus at the inner most layers that each can observe in the other. Accordingly they are incredibly subtle. I**f you can be more subtle than the other party, you can influence them in a way which eventually prevents you from losing (which may involve a joint mobility limit which permits you to kill them).** We can use this information to see more into what the strikes must look like. When you see a strike that isn't a deathblow, its goal is clearly to get more information. If you can learn more about the inner layers of intent of your opponent, you can subtly influence them at more inner layers. This means, with each strike, the Jedi remains sensitive to what the opponent is doing. **When the opponent successfully blocks the attack, the *way* they block the attack can reveal information about inner layers which the Jedi could not otherwise pierce.** For example, if the block reveals a Sith inner desire to strike at the lower right quadrant of the Jedi, the Jedi can offer "opportunities" in that quadrant which don't cause the Jedi to risk losing, but permit the Jedi to learn more about the Sith. This would suggest that the violent uncontrolled swings of Anakin vs. Count Dooku were not the swings of a Jedi, but a fool masked by anger because they put his senses in a very poor position to analyze the way Dooku's blocks "felt." Likewise, this also points out that the taunts in combat are actually valid combat techniques. **While taunting may be seen as a cheap way to make lesser opponents make a mistake, at the skill level of the Jedi and Sith, words may be as effective at subtle influences as a lightsaber is.** The long strung out fights with many blocks and parries may be realistic! Modern fighting theory suggests that most fights are over within the first few blows. However, modern fighting theory is not studying Jedi, with their extraordinary levels of perception. In a Jedi fight, you aren't always fighting to kill the other guy; you're fighting to get information about them so that you can influence them in a way that ensures you don't lose. This can lead to much longer fights than happen in more realistic circumstances, with less super-aware individuals. **What's the ultimate Jedi/Sith lightsaber battle?** It's actually really boring to watch, because it is too subtle for us. I borrow from the stories of a Chinese internal martial art called Tai Chi. > > Two great masters of the force met to determine whose mastery was greatest. They stood and faced each other, staring the other in the eye. They stood there for the longest time, never drawing their lightsaber, never twitching a muscle. Finally, both smiled, bowed, and walked off. > > > Why do I suggest this is the ultimate lightsaber battle? Consider, neither one would like to leave their ultimate victory up to chance. Not-losing is more important than winning. In the ultimate lightsaber fight, both parties influence each other so subtly that even the drawing of the lightsaber is superfluous. Eventually they identify a way to proceed in which both parties do not lose, and they go on their way. [Answer] The best way to fight with a lightsaber, in general, is to ***fight dirty***. **Fight like a sith.** [In a comment](https://worldbuilding.stackexchange.com/questions/31513/what-would-be-the-best-way-to-fight-with-a-duel-with-lightsabers#comment84163_31513), TrEs-2b provided [a link](https://i.stack.imgur.com/2lZya.jpg) to some excellent dirty lightsaber fighting techniques. I take no credit for these images; as far as I can track down, they were created by [Pere Pérez](https://www.facebook.com/PerePerezPPP), who has some other work showcased [here](http://pereperez.arscomics.com/). Several of the moves depicted below require the lightsaber to turn on or off in a very short time. How quickly a lightsaber activates is a bit of a debate (about Star Wars universe! No way!), but I think the question is [well answered here](https://scifi.stackexchange.com/questions/33081/how-long-does-it-take-to-activate-and-deactivate-a-lightsaber), clearly showing that such rapid activation *is* possible. [](https://i.stack.imgur.com/G9YbN.jpg) [](https://i.stack.imgur.com/RYhPD.jpg) [](https://i.stack.imgur.com/1xZdW.jpg) [](https://i.stack.imgur.com/NcTjQ.jpg) [](https://i.stack.imgur.com/k5dtr.jpg) [](https://i.stack.imgur.com/RZGgn.jpg) [](https://i.stack.imgur.com/MWVr4.jpg) [](https://i.stack.imgur.com/zEEQt.jpg) [Answer] Cort Ammon's brilliant answer can only be expanded on with one regard: observation of the other. Samurai sword duels between high ranking masters would resemble the initial duel between Kyūzō and an unnamed Ronin in the early part of the Seven Samurai. The two face off and select their initial positions, then there is a long pause before a sudden flurry of motion. Kyūzō simply announces "you are dead", which enrages the other ronin and they replay the duel with live blades in place of the bamboo used earlier. Sure enough, a setup, a long pause and a sudden explosion of action leaves Kyūzō standing and the other ronin lying dead in the field. Breaking this down, we see the two ronin observe each other, select a starting position (based on both their training at whatever dojo they belong to and what they observe of the other), then the pause where they select a strategy and wait for some sort of signal (a muscle twitch, a shifting foot) that might indicate the initiation of the attack. A more modern version of this can be seen in the movie "After the Rain" (Ame agaru), where the hero, another ronin named Ihei Misawa is being tested for a job as the fencing master for a local lord. Once again, the master (Ihei Misawa)observes the opponent, to the point of simply shifting his weight to avoid oncoming sword blows, before engaging in a swift movement to disarm his opponent (striking the opponent's blade from their hands). A final example is a legend from Japan, where a tea ceremony master is challenged to a duel by a samurai for some real or imagined slight. > > At the insistence of Lord Yamanouchi the daimyo of Tosa Province, a reluctant tea master was taken to Yedo (Yedo is the feudal name for the modern city of Tokyo.) on an official trip attired in samurai garb, including the two traditional swords of the warrior class. While running an errand for his master in the city, the tea master was accosted by a ronin (A ronin is a masterless samurai, literally a wave man (one who is tossed about like the waves on the sea). Lacking a benefactor, many ronin took up criminal endeavors to support themselves.). Since he was by himself and dressed beyond his station, this was exactly the thing the tea master feared might happen. > > > At first, he was so scared that he was unable to speak, yet was finally able to admit that he was not really a samurai. Upon discovering that his opponent was merely a tea master and not a fearsome warrior, the ronin was more determined than ever to take his money. The ronin declared that it would be an insult to the tea master’s province if he did not defend his honor. The tea master replied, “If you so insist, we will try out our skills, but first I must finish my master’s errand. Then I will return tomorrow morning for a duel.” > > > The ronin agreed and the tea master rushed to complete his errand so that he could talk with the master of a local dojo before his fateful meeting with the ronin. He intended to ask the sword master how he might die in the manner befitting a samurai. The sword master was taken aback by the question, saying, “You are unique. Most students come ask me how to use a sword. You come to me asking how to die. Before I teach you the art of dying, please serve me a cup of tea.” > > > Forgetting about his impending catastrophe, the tea master prepared tea in the manner he always did—as if there were nothing else in the world that mattered except for serving the tea. Deeply moved by the tea master’s intense, but natural concentration, the sword master exclaimed, “That’s it! That very state of mind is what you will need tomorrow when you go to meet the ronin. First think of serving tea to an honored guest and act accordingly. Draw your sword and close your eyes. When you hear his kiai (spirit shout), strike him with your sword. The contest will probably end with a mutual slaying.” > > > The tea master thanked the sword master and went on about his business. The next morning when he went to meet the ronin, he followed the sword master’s advice to the letter. The tea master boldly stood before his opponent, the embodiment of concentration. The ronin, who had previously seen a coward, now faced the personification of bravery. Instead of advancing to attack, the ronin retreated. Cowed with fear inspired by the superior concentration of his adversary, he turned and fled. After standing a while and hearing no shout, the tea master opened his eyes to gaze upon an empty street. > > > Using this construct, the two light sabre wielders would face off and pause,using both normal senses and the "Force" to determine the state and intentions of their opponent, before suddenly making a move. [Answer] Buy/create ~20 Lightsabers. Attach each of them to a floating drone (these are fairly ubiquitous in the SW universe). Set them up so the lightsabers spin around randomly and flicker on and off at a high frequency - this will allow them to "bypass" other lightsabers. Make sure you encode them so they won't accidentally destroy each other. When dueling another force users, activate all the drones and send them at your opponent. They should en-globe and them move in. Use your own force powers in a defensive/support role, to make sure they can't just easily take your drones out. Recall them when your opponent has been effectively mince-meated. [Answer] It seems like the most interesting combat would be that which treated the lightsaber as a "complete" weapon, **taking advantage of its unique properties**, rather than just a glorified sword. Samuel's [illustrated answer](https://worldbuilding.stackexchange.com/a/31521/16021) demonstrates some of these, such as its **ability to be quickly switched on and off**, and its "**infinite sharpness**" *(and vulnerability of its wielder to having parts of their body force-pushed/pulled into it)*. The lightsaber is **not a ranged weapon**. This might mean that lightsaber duels would start by the opponents attempting to **close on one another as quickly as possible**, so as not to give the other the time to turn on their lightsaber and get into a defensive posture. This could result in elements of a more **traditional hand-to-hand fighting** style. In close-quarters hand-to-hand combat, a lightsaber that has yet to be turned on would be much more like a firearm than, say, a knife, in that it would be **no deadlier than a blunt instrument**, but anything that gets in front of its opening could be destroyed. That could lead to an interesting combat style like the "gun kata" [demonstrated in the final scene in the film Equilibirum](https://youtu.be/U02E2sjwlLM?t=4m46s) -- the focus was not on disarming your opponent, but in bringing your pistol into an orientation where it would be pointing at some part of the body of your opponent, so you could fire. **Use of the Force largely renders this question moot**, as you could use it to simply switch off your opponent's lightsaber, or more permanently mis-align/damage its internal components so it no longer worked. It's also a much more elegant & low-effort attack to tug a crystal a few millimeters off-center than it is to force a large appendage of a strong person in a direction it doesn't want to go. In any event, it's certainly a compelling reason to use a more conventional melee weapon. [Answer] I like all the thought from the other answers but wanted to add something. A light saber is deadly whether you swing in an arc (like a saber) or stab with the point (like a foil / epee). If I was fighting with a light saber, I'd fight using foil / epee fighting techniques. It is much easier to block a swing of the sword than it is a stab. Anyone dropping his guard long enough to take a swing at me would be instantly skewered. It just takes one touch... [](https://i.stack.imgur.com/9yTxu.jpg) It won't let me post an animated gif so [here's the link.](http://cdn.makeagif.com/media/10-08-2015/_030W-.gif) The touch need not be pretty either. [Answer] A lightsaber is lightweight, with most/all of that mass in the hilt. It also basically ignores armor. So it's more like a fencing sword than like a medieval broadsword. Why are fighters swinging it around like they need momentum to hack through metal armor? Assuming I have a standard lightsaber and am not using the tricks discussed above, I'll use a fencing style. Stand with my body nearly sideways to the enemy, to present a small target. Use quick stabbing attacks rather than slashing. The hilt-based center of mass makes it easy to wiggle the blade around quickly to parry, and the absurdly sharp blade means I can score a killing blow with one poke instead of slashing. Or, a poke and a flick of the wrist to sever a limb/wreck an organ. All I have to do is parry and touch you to cause injury, so big swings are pointless and leave me vulnerable. Also, don't rule out mundane dirty tricks. Sand in the face. A cloak in the off-hand to hide attacks or throw at the enemy's face. (This is the original "cloak and dagger" style.) For that matter, why not have a blaster in the off hand? Sure you can parry the shots, but can you do it while our blades are locked? (I assume we somehow don't have gunpowder weapons, which are way faster than blaster shots.) If I've got telekinetic powers, why am I not standing back and throwing furniture at you too? Final, silly thought: how long can you make a lightsaber? I'd prefer a pike-length one to those fancy multi-blade designs -- or even a regular saber on a spear if the blade itself can't be made longer. [Answer] Force users can use the force to pull and push objects. Why not just simply throw the lightsaber, and use force powers to simply align it to go through your enemy? There are several advantages: * It's easier to surprise someone with a ranged weapon. Very little sneakiness required! * Your opponent cannot strike back; their options are to use their lightsaber to deflect yours, or dodge. * If you can turn the lightsaber on from a distance, you can throw it, and *then* turn it on for extra surprise! * You never need to worry about closing the distance between your opponent and you. (This is a real problem in fencing, martial arts, etc.) But there are some disadvantages: * You've thrown your weapon! You need to recover the lightsaber (which may be trivial for someone who can simply force-grab it back.) * You've thrown your weapon! (Again!) How will you defend yourself from blaster shots or another opponent if your lightsaber is way over there? * Not every jedi, or jedi in training, may be able to easily control a lightsaber in mid-air. Perhaps jedi lack the speed and finesse to do this? (After all, I've never seen small things get thrown in jedi combat!) * Maybe jedi can sense the force being used? If so, they could sense the force-guided lightsaber missile coming at them. Also, if the force allows some pre-cognizance, your thrown weapon give them even more reaction time! [Answer] The main difference, I think, is that you don't need to apply any strength at all. The gentlest touch will cut through any armor. In some places, sports [Battle gaming](https://en.wikipedia.org/wiki/Battle_gaming) rules work in the same fashion. I.e. The slightest touch in any valid part of the body (head usually not included), or event clothing, counts as a hit. I think this could give us some hints about how a real lightsaber duel would work, but we need to have some important differences in mind. Sports battle gaming is a competitive sport, and you are rewarded for hitting the rival before he does the same to you. With a light saber, if the rival hits you later you are dead anyway. So it must be a lot more defense-oriented. And of course, you must protect the whole body. I'm not sure how this would affect fighting, but as Cort Ammon said in his answer, Jedis and Siths aren't know for trusting luck. I guess they would be really, really conservative, slowly circling around each other, examining carefully each other's movements, from a safe distance, before entering a really fast and lethal combat. My HEMA experience suggest most duels would end with amputed hands, as that's the nearest target and after blocking a blow, you can just slide your laser blade through the other weapon until you just cut the hand. [Answer] Since a lightsaber is sharper than even the sharpest metal sword, many advanced techniques would fail (there are many were you have to touch your opponents or your own blade). These techniques are mainly used to break an opponents attack and counter it. Also many standard blocks and attacks would fail, due to the lack of a guard (especially the ["winden"](https://www.youtube.com/watch?v=TuI3ThPdhxw) techniques). What stays are the standard techniques of attacking and blocking that don't use your body parts or guard, which is a very limited set. Dodging would be much more important, especially considering Jedi and Sith have faster reflexes than normal beings, can jump higher, etc... Considering this, I think that lightsabers are the only melee weapons where the hollywood style of fighting with dodging and jumping all the time is somehow even quite plausible. Ref.: My own experience as a HEMA (Historical European Martial Arts) Practitioner. [Answer] My understanding of lightsaber duels was that it was impossible (or nearly so) for anyone OTHER than force users to use lightsabers. Jedi/Sith used the force to feel both the location of their blade, as well as the location of the opponent's blade in much the same way they "felt" incoming blaster bolts and deflected them. Powerful Jedi/Sith were able to "mask" this detection of their sabers, thereby making it harder for the opponent to track and deflect attacks. In addition to feeling the location of the physical blade, Jedi/Sith would also feel their opponents intent, and also would use their precognizance (similar to little Anakin's seeing the future in pod-races to make split second reactions) to help them determine how and where to strike. The opponent would also be attempting to use the force in this manner, and each would be attempting to "block" the signal, so to speak, so as to obscure their own moves from their opponents. This, coupled with the Jedi's lightning fast reflexes and the inherent weightlessness of the blade, meant that they could move extremely quickly, while still being able to block and parry 99% of the blows from their opponents. So, yes, due to this, saber duels BETWEEN FORCE USERS would look like it does in the movies. Between everyday common people, however, they would be just as likely to kill themselves with the weightless saber blade as to kill their opponent. ]

[Question] [ **Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- This question does not appear to be about **worldbuilding**, within the scope defined in the [help center](https://worldbuilding.stackexchange.com/help). Closed 6 years ago. [Improve this question](/posts/84958/edit) This is something I've been thinking about for a while. Say a block of marble is used to sculpt a statue. Most of the stone is chipped away and is effectively useless. Instead of it being tossed, can it perhaps be melted back down into bricks? I ask this, because it would probably require a lot of energy and heat. I'm also not sure if the melting and cooling process will change the material, such as making it more brittle. Edit: To clarify, I don't mean marble specifically. I want to know what it would generally be required to melt down the stone, if the cooling process will affect it and if it would generally be practical to do this [Answer] It depends on your rock. Rocks like **Granite**, with large crystal sizes, are the result of VERY slow cooling and crystallization. So although in theory you could remelt and recrystallize this kind of rock, you'd probably need hundreds or thousands of years to do it. **Basalt**, a fine grained igneous rock, would be fine. It would still need quite a long cool down time. **Obsidian** and volcanic glass would be very easy - by definition, this cools quickly in an eruption. No problem recycling, apart from the heat needed. Now the problems.. **Sandstone** (and other sedimentary rocks) - you could not melt these and re-form them, obviously. You could grind them down to sand grains, THEN try to press them back together with the appropriate cement (silica or carbonate, depending on the original rock). This would take pressure and quite a bit of time. **Slate** Now, not only would you have to grind this down, but also slightly recrystallize this under pressure at a few hundred degrees, with more pressure in the direction normal to the cleavage. For a long time. **Marble** You can't melt marble at surface pressures, it decomposes into calcium oxide and CO2. If you had a very high pressure crucible and a means of heating it, you could melt marble and re-crystallize it. **Blueschist** This is getting a bit hard. You need a pressure equivalent to about 20km of rock, and a temperature about 400 degrees C. **Eclogite** A type of very high grade metamorphic rock. 45km depth and c. 700 degrees C. For years, to get the crystal size. So... unless you specifically want volcanic glasses to work with, it would probably be a lot easier to just buy some more. Rocks take a long time to form, and usually under conditions of heat and pressure that are not cheap to reproduce. [Answer] An opportunity here to link up my all time favorite episode of How It's Made: [Stone Wool Insulation](https://www.youtube.com/watch?v=t6FWPTZjwLo). It is exactly melted and recycled rock, being done commercially. [](https://www.youtube.com/watch?v=t6FWPTZjwLo) The idea was inspired by "Pele's hair" which is a real thing found in Hawaii: molten basalt whipped into thin hairlike strands. In the video they show the making of artificial lava from crushed basalt (and slag), which is then whipped into wool and made into mats. Great stuff. [@Yagos](https://worldbuilding.stackexchange.com/a/84959) notwithstanding, it does not look like wildly advanced tech to me: melt stone, whip into wool, trim and press, use as fireproof insulation. This is not some research project either: folks are making this stuff and want you to buy it. [Answer] "Stone" isn't really a thing, in the way think of it. It's not a simple substance like plastic, glass, or metals that can be melted and molded. The properties that make a stone come from a complex interplay of many factors. Stones made from exactly the same elements and molecules can behave in radically different ways depending on how quickly or slowly they cool. **Marble**, specifically, is composed of calcium carbonate crystals. Normally it has started out as limestone, produced by biological processes, which is subjected to heat and pressure that causes the calcium carbonate to crystallise in an interlocking pattern. If you were to take that marble and melt it at atmospheric pressure, you'd actually destroy the calcium carbonate, and be left with calcium *oxide* and carbon dioxide. To melt it down while maintaining its chemical composition, you'd have to subject it to enormous pressure while heating it to around 180°C at the same time. This wouldn't melt the marble, but it would allow you to reshape it. You would then have to control its cooling very precisely, to allow it the time to form the interlocking crystal structure that makes it marble. This would likely take a long time, though I can't find exactly how long; generally, the more slowly something cools, the larger crystals it would form. The same answer applies to most other rocks as well. In most cases, if you simply melt down a rock and let it cool, you're going to get some form of *glass*. After all, we make glass by melting sand, and sand is simply pulverised rock. The way minerals *cool* is actually more important to what they become than what they started as. It's all about the size of the crystals you can form in a given sample. Take a look at this: [](https://i.stack.imgur.com/rQ419.jpg) This is a piece of nickle/iron alloy. Just iron, the same as your car is made of - but you'll never be able to make a piece of iron that shows a pattern like this. It's called a Widmanstätten pattern, and it will only form when the iron cools slowly. Very slowly. Like, *over millions of years*-slowly. It takes that long for large iron crystals to form. Marble, specifically, is similar - it needs to cool over thousands of years for its crystals to form their interlocking structure. Granite is composed of rocks that have been melted and then allowed to cool over thousands or millions of years. Sedimentary rocks that are melted can cool into granite. Rapid cooling of the same liquid rock would leave you with dense basalt or obsidian. So, while it's not *theoretically* impossible to use a combination of heat and pressure to reshape a sculpture or a carving back into 'virgin' stone, and while we could possibly do it today if we had a strong need, it's nearly always going to be much more practical to simply dig a new block out of the ground. [Answer] We produce bricks for construction by melting rock in blast furnaces <http://www.altocy.com/pdf/petro/TDS_FIBRANgeo_B-001_eng.pdf> However, most stone will melt at around 1500 degrees Celsius (2750 Fahrenheit), the previous company says they do it at 1520º C. So it is quite difficult and requires advanced technology. [Answer] Small fragments of marble or quartz are made into slabs of "engineered stone" for sale as floor tiles and kitchen bench tops. This product is 90-95% rock. The rest is mostly plastic to glue it together, and there may be some dye to make it different colours. It's formed at a temperature that's hot enough to melt plastic but not hot enough to melt rock. It's hard like stone and when it's polished it looks very nice. [Answer] Speaking of marble, yes -- historically people fed old architectural marble (e.g. old Roman marble) into lime kilns: to make mortar and concrete (["lime"](https://en.wikipedia.org/wiki/Calcium_oxide) being the key ingredient in cement, mortar, concrete) [Spaces in Late Antiquity: Cultural, Theological and Archaeological Perspectives](https://books.google.fr/books?id=BwM9DAAAQBAJ&lpg=PT253&ots=2GH1wRXUfv&dq=reuse%20marble%20lime&pg=PT253#v=onepage&q=reuse%20marble%20lime&f=false) > > ## Feeding Marble to the Kilns > > > Why did the population begin feeding the sculptural and architectural elements made of marble, which, as elsewhere, once decorated the public monuments and élite mansions in Galilee, to nearby limekilns? The main cause given by scholars for this kind of marble reuse is that it happened for economic reasons. As mentioned earlier, marble is superior to limestone when it comes to the production of lime. While that is the case, for most of antiquity marble was considered too rare and valuable a commodity to be used for this purpose and was, instead, used primarily for purposes of decoration and lavish display. When, by Late Antiquity, limekilns began to be built within the city limits, scholars reasoned that this was because, by that time, marble was amply available there in the form of architectural decoration and sculpture. Aside from marble's superior quality, reusing this stone from former urban structures also probably saved considerable transportation costs. According to these scholars then, the burning of sculptural and architectural marble in limekilns set up within cities during Late Antiquity was primarily chosen for its productive efficiency: the product was superior and transportation more cost-efficient. > > > So for this particular type of "rock" it doesn't take very advanced technology ... they were doing it in the real world, in antiquity. [Answer] There are of course other ways of re-using or not-wasting or re-purposing stuff. Rock pieces could be ground/crushed down very fine and then used to mix into some other substance to lend strength (think of making cement, or putting metal filings into something like JB Weld), or used to make other products (sandpaper is just fine ground rock/mineral of various types glued to paper) And of course, there are always uses for just small pieces of rock - drainage systems, as part of a large natural water filter, paving, etc. However, on a relatively small scale - like whatever leftovers there were after Michelangelo carved his David - wouldn't lend a significant enough of the left overs for economy of scale to kick in and make doing anything but keeping larger chunks to use for smaller works or practice, etc or tossing the smaller chunks into a French Drain. ]

[Question] [ **This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information. I was reading [this article from NASA](https://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html) about chemical rockets and they argue that, with a planet 50% larger than the Earth (assuming similar density, about 1.5G surface gravity), it would be impossible for chemical rockets to escape. Note that I don't care specifically about those exact values, just assume a planet slightly too big for chemical propulsion to be able to power a rocket to escape. If people were stranded on a planet like this, how would they build a means of leaving this planet. Assume that they have no help from anyone already in orbit, so they have to get to space on their own, and a planet otherwise similar to Earth. They can know as much or as little about our spaceflight technology as is convenient for the answer. Also, all answers must be feasible according to our current understanding of physics. Anti-gravity devices, portals, and the like are disallowed, though far-future tech can be used if/where needed. [Answer] A pulsed fission engine like project Orion would have been able to move a 10 million ton ship into earth orbit. The downside is that they were achieving the propulsion with nuclear detonations. They would launch the atomic-bombs out of the back and detonate them a good distance away with a giant hemispherical "pusher-plate" which was basically a giant shock absorbing piston with a cup at the end to "catch" the energy from the blast. [](https://i.stack.imgur.com/FHjz9.png) The concept was further refined at a later date to utilize specially constructed nuclear "shaped charges" known as casaba howitzers. These nuclear devices would have been created in such a way that they focused the blast into a large tungsten slug that would vaporize into a cone, or even beam shaped blast directed at the pusher-plate. It would have made the ship even more efficient with it's thrust and obliterated/irradiated less of the surrounding countryside. [](https://i.stack.imgur.com/mlFPn.png) The final on paper iteration of the plan could accelerate a space craft at 1G for 10 days. To give you an idea of how fast that is if you Accelerated at 1G for 5 days, then decelerated at 1G for 5 days you could reach Saturn in 10 days. Also it is a MASSIVE vessel. Since it's riding a series of thousands of nuclear shock waves the vessel's minimum size must be nearing the 1000 metric ton weight class just to survive launch. The vessel would have an order of magnitude larger amount of Delta-V required to achieve orbit, and as soon as it left orbit it could pretty much go anywhere in the solar system it wanted to. Shoot, if it used up all of its nuclear charges with zero regard for deceleration it could theoretically hit about 4% the speed of light. Keep in mind the pusher plate being shown here is approx **500 meters in diameter!**. Seems a bit extreme? I say irradiating an area the size of Texas is a small price to pay for progress! [](https://i.stack.imgur.com/wIdcM.png) [Answer] **This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information. With a [Lofstrom](http://launchloop.com/) [launch](https://www.youtube.com/watch?v=J1MAg0UAAHg) [loop](https://en.wikipedia.org/wiki/Launch_loop). Basically, you want to build a set of towers high enough that they can lift a train track all the way above the atmosphere. Then, in the absence of air resistance, you can accelerate your train all the way up to orbital velocity, and beyond. Now, building a tower in high gravity may not seem like it's really any better than trying to use rockets in high gravity, and if the towers had to be supported by static forces, that would indeed be a problem. We can't build a sufficiently tall skyscraper *on Earth*, let alone on a heavier planet. But the towers don't have to be statically supported. They can use dynamic support. And dynamically supported structures, unlike rockets, can scale to arbitrarily large sizes, as long as you have a sufficiently powerful (and reliable!) powerplant to run them. See [this video from Cody's Lab](https://www.youtube.com/watch?v=i4kTF0xw3y8) for real-world, small-scale demonstrations of the concept, one with water and one with a string. A typical Lofstrom launch loop would work more like the string launcher than like a water-jet tower, although fountain-supported launch tracks are also potentially feasible, as long as you have enough suitable anchor locations along the track. (A loop only needs anchors that can handle compressive loads at each end, not all along the way.) Imagine a string launcher that encases the string in a stationary, frictionless tube, except the "string" is actually a telescoping steel chain, the "frictionless tube" is an active magnetic levitation track, and the "rubber wheels" are a series of linear electric motors. [Answer] **This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information. And now for a ridiculously big approach: Build a ring around the equator. This is supported by a large number of towers. The ring is spinning well above orbital velocity (use a maglev setup, but there's a second one on top) and exerts an outward force. This is made equal to the weight of the tower beneath--thus the towers are actually hanging from the ring. (Yes, there are mountains and oceans in the way. I said this was ridiculously big--you're going to have to bore some mighty tunnels and build some pretty impressive deep sea constructs.) Once you have this ring working do it again--this time on top of the existing one. Repeat until you're out of the atmosphere and can put your launch track on top of the whole thing. As each ring takes the load of it's layer you don't need an insanely strong tower. I have not performed a full analysis of this but it's not needed to see that it works: Consider the extreme case with an infinite number of rings and an infinite number of towers--the materials strength requirement drops to zero. Thus it simply comes down to the required spacing. While this is a vastly more complex engineering project than either the launch loop or space fountain approaches it doesn't have the insanely powerful turn-around magnets those approaches need. You can duplicate or triplicate all the power elements so that if there is a failure the whole thing keeps working. As for the comment about the lack of hard science: 1) What's the force on the ring? You have an outward force between anchor points that matches the inward force exerted by the anchor points. Infinite anchor points = zero distance between them = zero force on the ring. 2) What's the force on the towers? The mass between a ring and the one below. Infinite rings = zero distance between them = zero force on the towers. Obviously, neither can actually be infinite but they can be large enough that there's no big materials issues. As for the Orbital Ring video in the comments: He's talking about building it in space--something not permitted by the question. I'm talking about building up from the ground, although the basic concept is the same. Note that his ring doesn't work--note my point #1 in response to the hard science gripe. You can't anchor that in only one point without the use of super materials. [Answer] ## Aircraft launch Use a winged vessel which uses the atmosphere as * a dynamic structure to carry its weight, * a source of oxidizer for its engines, and * reaction matter to provide thrust. The aircraft's goal would be to get as high as possible, but even more importantly as fast as possible, because in air launch, speed is worth more than altitude. (If altitude were so precious, we'd launch from the Wyoming steppe, not sea level). Right now we don't have reason to throw terabuck engineering into *hyper*sonic aircraft, but they sure would. So this aircraft would be climbing up into the very upper limits of the atmosphere where it's thin enough to go hypersonic easily, and creating all the delta-vee it possibly can using the atmosphere as oxidizer, before detaching the first stage of rocket proper and sending it on its way. The rocket equation would be more or less inapplicable to this mothership launcher, since its oxidizer and reaction matter is borrowed. There are [those working on this](https://en.wikipedia.org/wiki/Air_launch_to_orbit). However projects like [Stratolaunch](https://en.wikipedia.org/wiki/Scaled_Composites_Stratolaunch), Virgin [LauncherOne](https://en.wikipedia.org/wiki/LauncherOne), [GO](https://en.wikipedia.org/wiki/Generation_Orbit_Launch_Services), [Aldebaran](https://en.wikipedia.org/wiki/Aldebaran_(rocket)), and [MAKS](https://en.wikipedia.org/wiki/MAKS_(spacecraft)) are subsonic launch, [IAR-111](https://en.wikipedia.org/wiki/IAR_111) is "mere" supersonic launch. I am proposing hypersonic launch, and the mothership doesn't need to survive separation. [Answer] **This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information. Related to the launch loop there's the space fountain. You build a tower to space. Of course there's nothing strong enough to build it out of so you have to take off a whole bunch of weight. You do this by building a base station that throws magnets up (in an evacuated tube) very, very fast. Each platform of the tower has generators that produce a bunch of power from the magnets flying by--in doing so energy is transferred from the magnets to the platform. That energy goes next door to the motors that are grabbing the pieces coming down (think maglev train, you can't have physical contact!) and accelerates them, likewise producing lift. You have a very large magnet at the top that turns the pieces around and sends them back down. You have a **humongous** magnet at the bottom that does the same thing. So long as the paths is evacuated and everything is superconducting this costs no power once you have it set up. Regarding the hard science gripe: <https://en.wikipedia.org/wiki/Space_fountain> [Answer] **This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information. The problem posed in the article is that if planet's radius was 50% larger, current chemical rocket fuels won't allow rockets to escape earth's gravity. Per article, this is because Rockets have a design limit on how much fuel they could carry at launch, which limits their capability to escape from a planet of certain minimum size. But they can very well orbit. As long as rockets are able to reach orbits with even marginal fuel remaining, we should be able to create a solution based entirely on currently available (or near-future) tech, albeit very expensive. I suppose that's not of concern for rescue of stranded people. Consider a series of orbiting spacecrafts, that are essentially refuelling stations, lodged into orbits with some residual fuel. Installed solely to allow refuelling of final people-carrier-escape-vehicle. A reusable rocket in people-carrier-escape-vehicle in orbit should be able to refuel from these orbiting stations sufficiently to allow escape. [Answer] One possible solution would be to turn the highest mountain into a space gun. Depending on the density of the atmosphere at that altitude, either go straight to orbit or launch a vehicle (rocket) into a low orbit and from there use propellant to get free of the gravitational well. If we use the 9680km radius from the article and assume average density equal to earth we end up with a planet that has the following characteristics: Earth Avg Mass: $$5.98 \* 10^{24}kg / (1.33 \* π \* 6,378,000m^3) = 5516 kg/m^3$$ Our Planet’s Mass: $$(1.33 \* π \* 9,680,000m^3) \* 5516 kg/m^3 = 20.9 \*10 ^ {24} kg$$ Our Planet’s escape Velocity: $$( 2 \* (6.67 \* 10^{-11}) \* (20.9 \*10^{24} kg) / ( 9.680 \* 10^6 ) )^{0.5} = 16.9 km/s$$ Surface gravity: $$(6.67 \* 10^{-11}) \* (20.9 \*10^{24}) / ( 9.680 \* 10^6 )^2 = 14.88 m/s^2$$ Given the increased gravity we are unlikely to see mountains as high as the ones on Earth, but let's ballpark it and assume a 5km peak maximum. On earth we have drilled as deep as 12 km into the crust (granted with a 2 inch bit), so it is not out of the question that in the near future we will be able to dig a tunnel from the top of the mountain and continue 5km into the crust, basically creating a 10 km long barrel. We have rockets, even tiny ones like the SS-520-5 which can achieve orbit from earth. So to prove the concept we could have the space gun place a rocket at an altitude where the escape velocity equals that of earths surface. $$ \sqrt((6.67 \* 10^{-11}) \* (20.9 \*10^{24}) / 11.2 m/s^2) = 11,156,476m $$ Our space gun must be capable of placing the rocket at: $$11,156,476 – 9,680,000 = 1,476km $$ above the planet surface. Well that’s not going to work, since the furthest we have ever gotten with a space gun like setup is sending 180kg up 180km. Second option would be to accelerate the rocket so it leaves the mouth of the barrel with enough velocity to make up for the increase in escape velocity. $$16.9 km/s – 11.2km/s = 5.7km/s$$ Ian McNab [proposed a design](https://research.lifeboat.com/ieee.em.pdf) for a railgun that could accelerate a 400kg projectile to 7.5km/s back in 2003. However, I must admit the math is getting away from me when I try to build a model that accounts for atmospheric density at 5km altitude on our imaginary planet. The drag is enormous and there are huge structural challenges in accelerating an existing rocket to the tune of 165 Gees and not have it burn up once it leaves the mouth of the gun. In the end a coherent solution was beyond my ability. [Answer] What if we use a WEAV type system of propulsion to get to low earth orbit... <https://www.scientificamerican.com/article/worlds-first-flying-saucer/> This uses electrolodes and magnetic fields to create plasma that pushes the air away from the craft generating lift from any surface with few aerodynamics or moving parts involved, then you use 200 kilowatt magnetohydordynamic thrusters <https://www.nasa.gov/centers/glenn/about/fs22grc.html> to hit speeds close to 200,000 miles per hour with 200 (13 times that of the space shuttle) using noncondensable hydrogen plasma and electric power for fuel. [Answer] TCAT117 suggests a pulsed fission engine, but these are horribly contaminating and therefore have never been tested. <https://en.wikipedia.org/wiki/Nuclear_thermal_rocket> gives another alternative. This consists of a nuclear reactor as a source of heat, through which liquid hydrogen is heated and used as a propellant in a nozzle similar to a conventional rocket nozzle. This design was actually given some consideration and some engine tests carried out. It's much less hazarous than a pulsed fission engine, but chemical rockets are less hazardous than any of the nuclear options, so in the real world they won out. Hydrogen is the preferred propellant as its light molecules give the highest exhaust velocity at any given temperature. The following are highlights from the comparison in the Wikipedia article, which I have copied in here as requested: Specific impulse 850-1000 seconds, more than double that typical for a oxygen/hydrogen powered engine. Specific impulse is the number of seconds a stage can produce a thrust equal to its initial fuel weight before fuel runs out. It is proportional to exhaust velocity. Thus the simple solid core nuclear thermal rocket is capable of double the efficiency of a chemical one. Thrust - weight ratio achieved in apollo era (about 5:1 on a 1.5g planet.) This is much less than a chemical rocket, and means that nuclear thermal rockets are more suited to being used in upper stages where burn times are longer. The first stage (only) of a rocket needs high thrust-weight ratio as vertical takeoff means initially a lot of fuel is used fighting gravity. The sooner you can build some speed and get into a near-horizontal trajectory the better. Once this is achieved longer burn times at lower acceleration is not such a disadvantage. SNTP era (separate article) reached 30:1, a thrust-weight ratio at which engine mass ceases to be any real issue. <https://en.wikipedia.org/wiki/Project_Timberwind#Space_Nuclear_Thermal_Propulsion_Program> **NASA actually considered replacing the 3rd stage of Saturn V (known as Saturn IV-B) with a nuclear thermal rocket for enhanced performance.** The wikipedia article has a worked example based on the Saturn IV-B and I present a summary below. Delta V is the standard measure of efficiency of rocket in space, equal to the speed difference it is able to depart before it is depleted. The author seems to have neglected the mass of the upper stages. If factored in, this will further favour the Nuclear Thermal Rocket on the mass/mass comparison, as the engine mass will be less significant. **Standard Saturn VI-B Hydrogen-Oxygen fueled** Fueled Mass 119800kg, dry mass 13400kg, specific impulse 475s. Delta V (414 s × 9.81) ln(119,900/13,311), = 8900m/s **Nuclear thermal rocket, drop-in replacement matching volume/volume** Fueled Mass 38600kg, dry mass (due to increased engine mass) 17300kg, specific impulse 850s Delta V (850×9.81) ln(38,600/17,300) = 6,700 m/s. While the Delta V is lower, the mass of the stage is much lighter due to the hydrogen propellant being lighter than the hydrogen/oxygen bipropellant of the original stage, so the stages below will compensate. **Nuclear thermal rocket, replacement matching mass/mass** Fueled Mass 19000kg, dry mass (due to increased tankage) 38300kg, specific impulse 850s (850 s×9.81) ln(119,900/38,300), or 9,500m/s NASA considered an even smaller stage due to constraints of the Vehicle Assembly Building : 10,429 kg empty and 53,694 kg fueled. This would improve the payload capacity of the Saturn Vf from 127,000 kg delivered to low earth orbit (LEO) to 155,000 kg. **This is a moderate improvement on chemical rockets, based on Apollo era technology and far from optimised. An example based on project Timberwind would be a much greater improvment, 1.5 to 4 times payload increase. <https://en.wikipedia.org/wiki/Project_Timberwind#/media/File:SNTP_Upper_Stage_Applications.png>** Note that the Space Shuttle's second stage (the main engines) fired from liftoff, though most of the initial thrust was provided by the first stage boosters. I would foresee a similar arrangement with chemical boosters around a nuclear thermal rocket core, to keep the heavy nuclear thermal rocket engine burning for the longest possible time. An issue mentioned is that the specific impulse of nuclear thermal rockets is limited by the maximum temperature the reactor can withstand. I think a hybrid engine with a nuclear thermal core followed by oxygen injection into the hydrogen stream in an afterburner for liftoff could improve this issue to give even higher specific impulse, and would have great potential as a first stage. [Answer] **This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information. You would use a "cannon" to launch a projectile into orbit. Cannons use explosives and are not limited to the burning energy of combustible fuel. The mathematics of orbiting a projectile based upon velocity would be the same as rockets. The only exception is the projectile accelerates under extreme forces, but the speeds would ultimately be the same. Wiki describes the concept of a "space gun": <https://en.wikipedia.org/wiki/Space_gun> The challenges with launching projectiles into orbits are the forces, and materials required to keep the projectile together. A piece of technology like a satellite would be destroyed in the process, but you could package the satellite inside a hard shell. Package the satellite in a way as to have no voids, and reassible the unit into it's functional shape once in orbit. [Answer] This is a formidable problem. Let's break it down into two problems: how to get satellites into space, then how do we get people there? For satellites, you'll want an ion propulsion system as these have a much higher specific impulse (>3000s) than chemical rockets (~450 max). The problem is that ion propulsion has low thrust and won't work in atmosphere. So, you'll need to launch the satellites into space using chemical rockets before releasing them and turning on the ion thrusters. If the gravitational pull is still low enough to enable accelerating satellites into low "earth" orbit with chemical fuels the satellites will be able to steadily escape the planet via their ion thrusters without falling back down. When the time comes to get people out you could assemble a second rocket in orbit and use that to get away. Now, if you can't accelerate your satellites fast enough to sustain orbit you have a problem. You could install an explosive-propelled firing mechanism into the first rocket after it runs out of fuel to rapidly accelerate the satellite into a stable orbit. The advantage of this over a chemical fuel is that you can use high specific-impulse chemical compounds that would tend to explode if used in a thruster, and you would only need to accelerate the weight of the satellite rather than the rocket and fuel. It would then be physically possible to assemble a second rocket in orbit this way (using ion thrusters to adjust orbits), but putting a person into that rocket could be difficult as the acceleration from the firing mechanism would probably kill them. Suppose we can't escape that way. Let's use our firing mechanism system to put robots in orbit instead. If you have a moon orbiting the planet you could establish a robotic base there. Alternatively, you could assemble an artificial satellite as a base. If we assume that building an artificial womb is feasible, we could install one on our base and launch a frozen embryo into orbit. It would probably take a few attempts before you can remotely raise a child to adulthood, and would be insanely expensive to sustain them, but there's no physical law preventing it. You may now proceed to conquer the universe. ]

[Question] [ [(This *Monty Python* sketch got me thinking)](https://www.youtube.com/watch?v=WwbnvkMRPKM) Could a joke be funny enough to actually *kill* a person? By "joke", I'm referring to the written/typed and narrated types of "jokes" (videos, pictures, comedic actions don't count). **Conditions:** 1. Joke should be more or less equally lethal if either read silently or narrated. 2. Joke shouldn't take more than 5 minutes to mentally read/say out completely. 3. Death = (Brain death) + (Heart or multiple organ failure) 4. Creator of the joke must be able to record/write/type down the joke (albeit, while laughing throughout the process) before he dies. (Just Assume he's able to cook up the joke in under a minute) --- **Possible reasons why such a joke may not exist:** (*Victim hears/reads the joke*.) I suppose there exists the possibility of the victim passing out due to exhaustion (since he was laughing so hard)...which would prevent him from laughing to death. So any answer that's going to be accepted *must* factor this into account. [Answer] Can people die from laughter? Yes. There is a [wikipedia page](https://en.wikipedia.org/wiki/Death_from_laughter) about this. However, such incidents are far and few between - I found three in the past century, and one of them was exacerbated by a heart condition. Are some of those cases from a joke? Only one incident I found confirmed the cause of death to be a joke as defined in the question (Wesley Parsons) So, given the case of Mr. Parsons, yes people have died from laughing at jokes. Could there be a universal killing joke? Absolutely not. People have different senses of humor, and so will laugh different amounts at a given joke. Therefore, it won't work on everyone. In addition, there is very little research into how exactly people die from laughing, so a given person could be immune to death by laughter. [Answer] There are some issues with this, but let's handwave the deadliness part for now (we'll get there). The first issues you need to deal with is spread: If knowledge of the joke can only be gained by reading or hearing it, then everyone who hears or reads it will die from the lethal joke. In theory, it cannot be written down in the first place, because the writer would need full knowledge of the joke, and thus die before finishing writing the joke. This, naturally, assumes everyone is equally vulnerable to the joke. Let's assume now that some percentage of the population is immune to the joke. Perhaps they don't have some underlying condition, or they just don't have a sense of humor. Now, we do have a mechanism for which the joke could be distributed throughout the world. By these people intentionally telling the joke (there's some issues here in that if the person did not find the joke funny, or realized it would kill people, they would not necessarily spread the joke). Your joke is basically a virulent disease. If it is too virulent, then people will die before spreading it, but if it isn't virulent enough, you don't get your desired effect (a deadly joke). It's possible the joke is a "thinker" and takes some time to be funny enough to be deadly. Perhaps enough that you will, after being "infected," tell it to others, before it kills you. It is also possible to have people "immune" to the joke, who will never get it, but may continue to spread it throughout the world. In terms of plausibility, I'm going to go with no, for many reasons. First, it takes some severe underlying conditions to die from laughter. It's possible something in the joke is so obsessing you forget to eat or drink, but the body really tries hard to live, and overriding these urges takes a lot. The most promising route (and easiest to hand-wave) is that the joke sets up some kind of dissonance in the subconscious, and when the person sleeps, they literally scare themselves to death by some nightmare. You could, in theory, also have a logic trap that locks up the brain, but you'd have to get beyond the brain's natural Paradox Absorbing Crumple Zones. [Answer] As a comedian, I write jokes. Some always make people laugh, but will never make me laugh, since I created it. I saw how the sausage is made. I know the misdirection, and then punchline is coming. I believe the joke writer would be immune to the humor and its consequences. Nobody likes a comedian to laugh at their own joke. [Answer] It would work if the joke's creator wasn't human. This is exactly the sort of malarkey you might expect from an Elder God like Cthulhu, or an alien scientist wanting to test the frailty of Man, or a space-clown who enjoys ironic carnage. It is probable that such a joke would not kill straight away but initiate a decent into madness followed by stroke, heart-attack, grisly suicide or being killed by security forces in mid-rampage (all while screaming the joke and laughing maniacally). ``` Knock-knock. Who's there? Cthulhu. Cthu-who?... Wait... What?! Ahhh MY BRAIN!!! ``` [Answer] In order for the joke to be created in the first place, the creator would have to not "get it", or he would be the first and only victim before he could relate it either verbally, or in writing. So, your creator should either create it by accident, if of low intelligence, or autistic or have some other basic lack of sense of humor. Then, the spread of said killing joke would have to be through a stealth-vector. The best kind would be one that would take time to "sink in", the equivalent of a gestation period of a virus so that a person could pass it on before they "got it". Upon getting the joke a person would laugh so hard and long as to cause either cardiac arrest or asphyxiation. Both causes of death are known to be the results of too much laughter. [Answer] Umm... The obvious problem would be the death of the joke creator (as depicted in the Monty Python sketch) If such a thing were possible, how does the creator protect themselves from their own creation? How would they know that they had created a lethal joke? How could they share their creation? Luckily no such thing is possible without other significant factors, such as the victim having a pre-existing heart condition or breathing problems... This is stretching things pretty far though. A victim so predisposed to death will die under any significant strain, even a mildly entertaining joke may put them at risk. [Answer] A lot of responses on here seem to be unable to get past the obstacle of the joke creator dying from thinking of the joke. That isn't a real obstacle, since, in theory, the joke could be devised by an AI program. Also, a lot of responses seem to be unable to get past the obstacle of how a messenger could relay the joke without dying. That also isn't a real obstacle, since the joke could be delivered via an internet message, telegram, video, etc. without human intervention. It's not unreasonable that after AI generates the joke, it could, in an automated fashion, use a bot account to send a private message to the victim via social media, or create a video and post it on youtube, or something of that nature. It is definitely within a computer program's ability to automatically generate videos, and you have probably seen some on youtube without knowing it. Can a person die from laughing at a joke? Yes. For the most part, this has a lot more to do with the person's overall health and psyche than the contents of the joke itself. But if a joke were gargantuanly hilarious, it might be able to kill many healthy people. It would just have to be a multiple of as funny as a joke that could kill an unhealthy person. Is a person and/or AI clever enough to construct a joke that is that funny? All I can say to speak to that is that there are already automated systems that make psychological profiles of everybody in America, use AI to formulate memes / rhetoric that would be most persuasive to influencing their opinion, and distribute it through social media using bots. So the same approach would definitely be usable to make automated systems that can make a deep psychological profile on a specific assassination target and formulate jokes that would be highly funny for that person. Even moreso, since said jokes are targetted for that person's unique psychological make-up, it might be lethal only to the target and some other similar people, and therefore might be sub-lethal for most other human messengers that are telling the joke. <https://www.theguardian.com/politics/2017/feb/26/robert-mercer-breitbart-war-on-media-steve-bannon-donald-trump-nigel-farage> Also, circle back to the theory that a lethal joke would kill the writer of the joke itself... if it is such a struggle to construct a joke that is lethal, and if your very best effort is barely sufficient to do the job, then this joke wouldn't be lethal to anyone that is marginally less vulnerable. So, for example, if a human architect of the joke found the joke 20% less funny, then it wouldn't kill them (this is a stretch, since people often find their own jokes funny). But messengers on the other hand... it's very plausible to teach the joke to a messenger in a way that is very unfunny, for example, by repeating the setup hundreds of times before they ever hear the punchline, or by teaching them the joke while under chemical sedation so that their heart rate never gets too high. By the time they're reciting the joke in a live setting, they've already heard the joke under sedation many times, they've rehearsed it in rote fashion, and the joke has gotten boring and routine. [Answer] I can remember at least two stories using somewhat similar ideas. One was Henry Kuttner's "Nothing but Gingerbread Left", where they write a song in German that doesn't kill, but is "going around a guy's skull, and he'll find it difficult to concentrate", and it only works on Germans (it's a short story about the World War II time). The other one is of a Russian author, I don't think it ever got translated to any other language. It is about a KGB scientist who invents a phrase that kills you if you are an "average" native speaker of Russian language and if you read the phrase from a piece of paper with your eyes. The author takes a serious and scientific-esque approach to the story, according to which the phrase is composed in such a way that it activates specific areas of the brain so that their electric activity resonates through some deeper structures of the brain (controlling the heart, lungs etc.), putting them into disarray. [Answer] It might stretch the definition of a joke, but it is plausible that a person could be hypnotised in 5 minutes and then persuaded to laugh uncontrollably which may lead to the person sustaining a fatal injury (e.g. falling and hitting their head). [Answer] Consider the following circumstance: One reads/hears a very funny joke while eating. The person accidentally inhales while breathing/laughing, chokes and dies. I've both choked while laughing, and saved a friend with the Heimlich maneuver in this situation. [Answer] I'm going to say **Yes**. The joke will be deadly to anybody who reads it, whether silently or aloud. It will even work whether or not they understand the langauge it is written in. They will find the joke hilariously funny no matter their sense of humor, and they will laugh themselves to death. How? A couple of closely related possibilities. One is that the joke is written in a primitive language intuitively understood by all humans. Like the virus in *Snow Crash* it will infect any mind that is exposed to it with a powerful neural meme which will trigger a reaction in the brain to try to rid itself of it, with the side effect being a powerful giddy sensation, feelings of mirth, and uncontrolable laughter. Once infected, the person will perish in short order as the virus takes over the mind, driving the person insane with laughter until they die from asphyxiation or apparent suicidal behavior. A similar possibility is that the words themselves are a kind of back door in the universe, a kind of hack which triggers a garbage collection algorithm on the reader's brain, causing the person to die in a fit of laughter. Whether this hack is due to reality being a simulation like the Matrix ("sudo gc self") or because of the existence of magic where spoken words invoke power (making this joke basically a spell that the reader unwittingly casts upon themselves) is up to you. [Answer] I'm not sure why so many of these answers are getting hung up on things like killing the creator. If you compare your hypothetical deadly joke to other instruments of death, other types of killers generally do not have the same flaws... so why does this one need these flaws? 1. Not all humor affects everyone in the same way. Somebody guffaw for days at a joke, while others don't even chuckle at the same. A joke that is deadly could simply not be equally funny to everyone, and therefore not equally deadly to everyone. 2. Not all deadly situations kill reliably. Getting shot in the head can often be lethal, but people like Gabby Giffords have survived being shot in the head. Sometimes poison kills with small amounts and quickly. Other times it takes a much larger amount of the same poison. People have survived falling from great heights, yet most falling people die. Your deadly joke could simply be unreliable. 3. Not all deadly instruments are unidirectional. If a gun was as dangerous to the person shooting, not to mention the builders, as it was to the person being shot, then that would be a pretty poor gun. A deadly joke could equally have some type targeting mechanism. What else is a joke than some communication? Have you ever polled a group of people, all who listened to the same speech? It's not uncommon for every one of them to have wildly different interpretations of the speech. The same could be true for your joke. 4. Not all deadly things are immediately deadly. A virus or bacteria may not kill the host for awhile, all while spreading it around. If the host immediately died, then the virus/bacteria would have no host to survive in. Your joke could be told to people, stay latent inside of them, and then weeks later while they're thinking about it could consume them with uncontrollable laughter leading to their demise. You could make your deadly joke as broad and indiscriminate or as specific and targeted as you like. [Answer] A joke for humans is very similar to a virus for computers: it's a piece of information that compels the receiver into taking some action and spreading it further. We, humans, usually find laughter a pleasant experience, and that's the joke's primary method of spreading. One can say that sense of humor is a flaw in human brain not unlike as security vulnerabilities are flaws in software design, that the joke exploits. A joke is a kind of [meme](https://en.wikipedia.org/wiki/Meme). We already have some memes that are indirectly deadly either to the people receiving them (eg. suicide cults) or to other people (eg. "we must kill others"). But they're neither involuntary body responses nor motivate spreading with humor. I think that you'd need to do what malware authors do: they find a vulnerability and exploit it (infection) in order to deliver the payload and run it on a victim. Those 2 are often separate pieces of code, not dependent on each other. So, now that you have human vulnerability that allows spreading, you need another vulnerability that allows killing the host with information. That's exactly what a funny clip with epilepsy-triggering strobe is: the humor compels spreading and absorbing the payload which then attempts to damage the viewer. Bottom line: for the killer joke to work, you'd need to create another vulnerability in humans of your world that would allow the joke to kill. Or increase severity of side effects from laughter. [Answer] The responses regarding lethality are interesting. I suspect that the body / mind has decent defensive mechanisms here, and that you would need to combine the laughter with other conditions. * a weakened heart * high blood pressure * or environmental factors such as a toxic gas or underwater environment. Laughter would make it very difficult to hold your breath. Some responses commented on the contagiousness of laughter which is something I've always been fascinated with, for similar story-writing reasons. The phenomenon is known as [emotional contagion](https://en.wikipedia.org/wiki/Emotional_contagion). If you could find a way to super-sensitize the [amygdala](https://en.wikipedia.org/wiki/Emotional_contagion#Amygdala), you could possibly heighten the effect of the emotional contagion. Unfortunately I can't locate the original article that introduced me to this topic - 3 girls in Australia who couldn't stop laughing for more than a year. It started with a joke. Fortunately for me, the joke was not part of the article. In Africa there was a similar experience affecting an entire village for 3 years, known as the [Tanganyika Laughter Epidemic of 1962](http://articles.chicagotribune.com/2003-07-29/features/0307290281_1_laughing-40th-anniversary-village). > > [strong emotions synchronize](http://www.psyarticles.com/emotion/contagious-laughter.htm) the brain activity of different > individuals > > > Here is a good example of the [contagious effect](http://newscrusher.com/video/woman-reads-funny-text-and-spreads-contagious-laughter-throughout-subway-cabin/). [Japanese comedy](https://www.youtube.com/watch?v=3GHbmTa1iNw) likes to [exploit this](https://www.youtube.com/watch?v=VGW-cfP3CqE) as well. This would explain mob behavior as well, and is likely the foundation of most forms of mass hysteria. As a weapon of war, where you want to incapacitate a population, emotional attack could be quite effective. [Answer] Write a really good joke inside the plate as the joke creator will be serving the food. Any person who reads the joke while eating will be dead chocking on the food. [Answer] Your rules don't specifically say that the person reading or hearing the joke has to be the one that dies. What about a joke that is only funny in the setting of an operating room. And when told while a doctor does an open heart surgery, it makes the doctor laugh so much that he can't keep his hands steady and the patient dies. That would be a pretty morbid "deadly" joke. [Answer] The human brain is a weird thing, and not very well understood. It can take specific stimuli, and respond to them in a way that is very counter-intuitive and unexpected, and does not have to have any obvious evolutionary reason. I am thinking specifically of the real-world McCollough effect - after you look at a specific image for a 15 minutes, some other visual scenes will have a colour effect for up to 3.5 months <https://en.wikipedia.org/wiki/McCollough_effect> Making this "killing joke" similar to this would have distinct benefits - since it is visual, the person finding it may do so randomly, e.g. on a photo, if the photo was taken by accident - by the time the image is seen, it has already been recorded. It is independent of language. Nobody knows why or how this effect works. Neural networks (like human brains and AI) are naturally prone to this sort of weirdness - any "visual" neural network that has no state can be probed to find weaknesses, especially if internal state can be examined - as in <https://www.theverge.com/2017/4/4/15177512/google-youtube-content-ai-fooled-tricked> and <http://www.evolvingai.org/fooling> ), and neural networks with persistent state can be fooled in the same way (though figuring out a way to do so is more difficult). An example of this is tickling. Tickling is not really in any way humorous, yet we still laugh. Tickling has no obvious connection to breathing, or humor. We take it for granted that this happens, but it is actually really weird. When tickled, we laugh even if we are unhappy or angry about being tickled. Neural networks work by neurons (or digital simulations thereof), when they trigger ("fire"), will send signals to specific other neurons through connections; if those other neurons get enough of the signals, they will fire in turn. It is entirely plausible that the right state could be partially, or wholly, self sustaining. I think it is entirely plausible that a specific stimuli could cause laughter, similar to being tickled, but in this sort of neural loop. if this lasted long enough, the person could choke or suffocate. [Answer] What if a language had been specifically designed to kill? Or broadly manipulate the user into actions? E.g. <https://en.wikipedia.org/wiki/Babel-17> Of course, language (and way of thinking) are social constructs and take years for children to become adept in the multiple ways of using them. Jokes and humour are some of the earliest uses of social interaction, I know my 4yo daughter is coming to tell me her 'jokes'. Some claimed that laughing is insticitve but we learn to cry (<http://www.dailymail.co.uk/sciencetech/article-1328640/Why-laughing-instinctive-learn-cry.html>). But what if the language and the education system were actually, year after year, preparing the correct (susceptible) frame of mind for the joke to operate? **Like a 'termination' command!** The recipient would never know it, they would even repeat the joke were they asked - were they not so very depressed in the time afterwards. This depression would go into an self-feeding loop (the joke's on me) and after some time it would be too much for the person to handle. **They would commit suicide.** ]

[Question] [ Imagine some settlers are looking to build a castle in an area of expansive plans discover a small, isolated mesa: the formation has a very steep face, rising up 10-20m. The area of this formation just so happens to have just enough surface area for the castle they would build there. The builders would construct an sort of earthen ramp along the face of this formation to be able to reach the gate. However, there is also the rest of the vast plain where they can build the same castle at the same elevation as everything else. Generally, holding the high ground in battle is advantageous, as Obi-Wan et al. have proven. In this case, **are there inherent risks to building an elevated castle that one on flat terrain doesn't need to consider?** Is the extra visibility a concern? Given medieval weaponry as advanced as catapults, crossbows, etc., is there a serious threat of undermining the walls? What if early gunpowder weapons like cannons are introduced? [Answer] # Consider [Masada](https://en.wikipedia.org/wiki/Siege_of_Masada) [](https://i.stack.imgur.com/k1nuc.jpg) This fortress was broken only by the Romans building an extra ramp up to the top of the mount and moving siege weaponry up said ramp. A fortress built in such a location can be as impenetrable as fortresses come. The problem being that, as General Tacticus said, > > If the enemy has an impregnable stronghold, see that he remains there. > > > The fortress may not be broken but you're not doing a lot while you're holed up in it. So only the usual food, water etc. as the standard weaknesses of a fortress under siege. [Answer] TL;DR: **Erosion of the mesa itself.** As luck would have it, this time last week I was visiting a castle that's almost exactly as you describe. It's called Bamburgh Castle, is located in the north of England, and has existed on the same site in some form or another for around 1400 years. It was built atop a large outcrop of stone (chitstone, I believe), with a stone path leading up to the main structure. [](https://i.stack.imgur.com/Iv3uo.png) However, chitstone is not particularly weather-resistant, and Bamburgh Castle is located right next to the North Sea: [](https://i.stack.imgur.com/g3Gw8.png) Due to a combination of human activity and natural erosion, the rock the castle sits on has gradually weathered away to the point that one wall was actually undermined and partially collapsed. It's been rebuilt, and the trust that oversees the castle have sprayed the exposed rock with concrete in an effort to stop the weathering. While natural erosion will take centuries to endanger the castle in this way, enemy forces can easily speed up the process by employing sappers to dig into the mesa and undermine the castle foundations. (As a final aside, Bamburgh Castle was the first British castle to fall to cannon fire, during a nine-month siege as part of the Wars of the Roses in 1464. So to corroborate Separatrix' accepted answer, your castle would also be vulnerable to siege warfare.) [Answer] This was done in France with a castle called [Mont Saint-Michel](https://en.wikipedia.org/wiki/Mont_Saint-Michel), and it's surprisingly effective. Disclaimer: Most mesas have a river, but not a tide cycle. It's not unheard of, though. [](https://i.stack.imgur.com/1fjFJ.png) As you can see, this castle was created on a small patch of raised land, which happens to be located in the Normandy territory of France. This castle was built with the tide in mind. Every 12 hours, the tide would rush in and everyone not in the walls would become stuck and wet. This means that laying siege to this city is insanely hard, as all land within a ~5km distance is flooded. The inherent danger to this, is occasionally, the city itself would find its own feet wet, and of course, not being able to go outside means many diseases. [Answer] Generally, I can't think of anything wrong with it. The Japanese in fact built their castles in a similar-ish way (admittedly by shaping the hill itself and giving it the steep stone walled sides you see below) [](https://i.stack.imgur.com/XHUPK.jpg) Note that the grass area within the walls are at the same level as the fortifications. The only risk I can imagine is if the rock/dirt making up the mesa just happens to be fragile in a particular location, or if there is a cave system underneath. [Answer] Unless the mesa contains a natural spring to provide an unlimited water supply, your settlers might be wise to build out on the plain where there is water, rather than in the heights where there is not. The mesa might also have disease-infested indigenous life such as rats or bats. Such infestations would be very difficult to eradicate with with medieval technology. If your settlers do choose to build out on the plain, they will want to put some distance between themselves and the mesa, to keep any enemy from using its heights against them. [Answer] The real problem is that generally people only want to do so much work or walk so far in a given day. You can call this a "human factors" issue. Anyone who is living a pre-modern lifestyle has to deal with moving water, clothes, crops and tools significant distances if they don't live directly where they farm or work. And in a society like this, generally 90% of them are farmers. Specialized fortresses like you are talking about can be be made to work, but often must take special efforts to supply and keep secure. The people doing the daily stuff--including guarding the place--are likely to be annoyed by the distances they must move and carry stuff. As a consequence, they are likely to damage the inherent security of the place by creating all kinds of shortcuts through or over what should be secure walls. Alternately, when the place is truly inaccessible and secure, it usually gets abandoned after a while, as people doing the real work move away and the rulers cut cost by forgetting about those inconvenient places. You can tell this by the fact that there are many, many forgotten fortifications around the world. Archaeologists are turning them up all the time. So to sum up: you can make great fortresses, but a good and practical fortress is close to where the people are. Those are the ones that will be in use centuries later. [Answer] The disadvantages are mostly economic. * Getting goods up/down there is expensive and takes time. * More expensive to build. * Maintenance is more expensive. * Establishing the castle as a trading hub is very difficult. * Having access to groundwater is less likely, limiting the number of troops that can be supported. There are some direct military disadvantages as well: * Launching counterattack on the besieging army becomes very difficult. * Sieging the castle by starving them out becomes much easier (just need to block the single exit). * Much harder for the castle to let reinforcements join them during a siege. All in all, these locations are great for monasteries, which are less affected by the downsides but still need protection from raiders. [Answer] > > A [Volcanic plug](https://en.wikipedia.org/wiki/Volcanic_plug) also called a volcanic neck or lava neck, is a volcanic object created when magma hardens within a vent on an active volcano. When present, a plug can cause an extreme build-up of pressure if rising volatile-charged magma is trapped beneath it, and this can sometimes lead to an explosive eruption. Glacial erosion can lead to exposure of the plug on one side, while a long slope of material remains on the opposite side. Such landforms are called crag and tail. If a plug is preserved, erosion may remove the surrounding rock while the erosion-resistant plug remains, producing a distinctive upstanding landform. > > > These were preferred sites for [castles](https://en.wikipedia.org/wiki/Edinburgh_Castle#Geology). Someone called them the nuclear weapons of the Middle Ages. There is little risk of undermining the walls. [Answer] When your castle wall is at the edge of a cliff, it would seem more difficult for an enemy to approach than if it were on a (less steep) hill. But it would be easier for them to avoid detection and/or to dig under. But notice that San Marino lasted nearly two thousand years on such a cliff. [Answer] Aside from water supply issues, undermining is the main concern. The castle's vulnerability to undermining depends on the composition of the mesa, plus whether any factors in the landscape make erosion/undermining attacks easier. If it's possible to divert a nearby river & the mesa is not made of strong rock but something more crumbly, then it should be possible to destroy the defensive walls in only a few days by that technique. A hard rock foundation is going to be a lot more secure. Since I don't know exactly how advanced the attackers are supposed to be, here's a good rule of thumb to decide if they could destroy a castle built on a strong rocky mesa: Ask, could they tunnel thru a mountain, like in the early railroads? If so, they can probably destroy a castle built on a mesa. Otherwise, the castle probably has the advantage [Answer] Lightning - there are still arguments about the best way to protect against it, but back when castles were build, nobody had a clue. Maybe have a tower with metal you need to melt down? Or a religious symbol at the top- to give more meaning to the lightning. [Answer] One more historical example: [Sigirya](https://en.m.wikipedia.org/wiki/Sigiriya) - the "Lion's Rock". The stories about its exact origin and purpose are a bit unclear - it was supposedly built by Kashyapa, the king's son by a consort, who killed his father the king and usurped the throne from the legitimate heir, who fled. Fearing the heir's return, he built the fortress - a place of luxury at the top of a 200m tall rock with excellent views of the plains all around; strategically unassailable (picture from Wikipedia link above) [](https://i.stack.imgur.com/AkijC.jpg) In the end, the brother returned with an army. Meeting him for battle **in the plains**, Kashyapa's army is said to have fled when they misinterpreted his manœuvre on his war elephant (to take a strategic advantage) as a retreat; seeing all was lost he committed suicide. Moral of the story: don't kill your dad. And if you build a castle to defend yourself, it doesn't help you when you go outside. [Answer] Without gunpowder this sort of Castle is almost impregnable. However, with the advent of cannons having a tall castle loses many of its benefits and gains many weaknesses see. [Gunpowder artillery in the Middle Ages](https://en.wikipedia.org/wiki/Gunpowder_artillery_in_the_Middle_Ages) But this is not relevant for the early cannons, as they were far weaker than most seat reference at the time. [Answer] A castle served several purposes. It is an obvious sign of power, it is a refugee in times of danger, and it is a command and control point for terrain. So it's location is critical. A mesa surrounded by steep walls on all sides is excellent for many reasons, but has some disadvantages. For starters, on a large plain is the mesa located near a water source? Not only for water for daily use and in case of a siege (cisterns can be filled for this), but rivers are usually the main means of transport in the medieval era, so a castle ought to be situated to control river traffic. A mesa several days away from the main river in the plains isn't going to be in a good location to control it. It will also serve as a refuge for local farmers, so it needs to be located near the settlements. Second, a mesa is great for defense, but if it is too contained then it can be itself surrounded and enclosed. The Romans did this at Alesia (as featured in a recent Hardcore History podcast). So while a mesa may seem ideal for defense, a site what has a flank protected by water may actually be better, since it allows for naval resupply, escape, and prevents physical encirclement. Third, 10-20 meter cliffs may seem high, but this is only a delaying feature. Siegecraft was highly advanced in it's day, no defense was absolute. But in general a mesa like this on an otherwise featureless plain was a good choice, one made many times. If a natural hill couldn't be used, folks would build one. There is a natural progression of these sites from a wooden motte and bailey castle to more permanent stone structures and walls. Of course out on a plain there may be a dearth of building supplies, so a mesa could be the ONLY defensive structure available, making it even more valuable until a stone quarry or brick making facilities could be built. ]

[Question] [ I want to create a sci-fi story, and since galactic warfare is on a larger scale, nukes wouldn't do much damage (or I wouldn't think so anyway). I would like ideas about an ultimate deterrent that could destroy stars (or a bomb with a supernova blast radius would work too). By "to destroy a star", i mean to kill off the star by causing a supernova, but any way to destroy a star works for me. Assume that warp technology is available and transportation across a galaxy is quick. Additionally would dropping an antimatter bomb on a very unstable star do any damage? (I've had another idea: what if you use energy from a star, concentrate it into a warhead, and the use the warhead to create a nova blast. is it plausible?) [Answer] **Want to improve this answer?** Add details and include citations to explain why this answer is correct. Answers without enough detail may be edited or deleted. > > **WARNING: While this post does point to a scientific paper there are a lot of doubts about the quality of that paper and how reliable it may be. The review process of the paper, credentials of the author and validity of the claims have all been questioned. Unless or until those questions can be answered any information from it should be used with caution.** > > > At least one real life mad scientist seems to believe this is indeed possible, and with technologies that are at least conceivable with todays understanding of science and technology. > > ABSTRACT > The Sun contains ~74% hydrogen by weight. The isotope hydrogen-1 (99.985% of hydrogen in nature) is a usable fuel for fusion thermonuclear reactions. This reaction runs slowly within the Sun because its temperature is low (relative to the needs of nuclear reactions). If we create higher temperature and density in a limited region of the solar interior, we may be able to produce self-supporting detonation thermonuclear reactions that spread to the full solar volume. This is analogous to the triggering mechanisms in a thermonuclear bomb. Conditions within the bomb can be optimized in a small area to initiate ignition, then spread to a larger area, allowing producing a hydrogen bomb of any power. In the case of the Sun certain targeting practices may greatly increase the chances of an artificial explosion of the Sun. This explosion would annihilate the Earth and the Solar System, as we know them today. > > > Alexander Bolonkin, Joseph Friedlander; "Explosion of Sun" <http://www.scirp.org/journal/PaperInformation.aspx?PaperID=34277> Assuming Bolonkin is correct, you would need to introduce a massive amount of energy into a very small area of the Sun over a very short time frame to trigger this fusion cascade effect. We might believe that energy releases many times that the "Tsar Bomba" would be needed, but according to the calculations in the paper, as little as 0.5Mt. detonated deep within the Solar Photosphere. I'll leave you to check the math and other assumptions of the paper, but as a lower bound, it is rather unsettling to contemplate. [Answer] ## You can always drop a chunk of degenerate white dwarf into it. If the mass of the target star + your bomb is greater than the Chandrasekhar limit it makes a [pop](https://en.wikipedia.org/wiki/Type_Ia_supernova) that would startle some people. You would need at least a .4 solar mass object to do this. ## Operation Giant Steelie Procure a solid mass of iron .01 times the mass of the sun get it spinning until atoms at the equator are fixin on breaking free. This is a while past when they reach escape velocity. Gently lob it into the solar north pole. Because of conservation of angular momentum, this will cause the sun to flatten out and break apart. [Answer] Nukes would indeed do basically nothing to the sun, it's a nuke far bigger than anything we could ever make continuously exploding for millions of years. Equally anti-matter - you'd need an absolutely monumental amount to even make a dent. This is something a lot of sci-fi writers get wrong. Stars are massive. Absolutely mindbogglingly enormous. To put that in perspective our sun could consume the entire planet earth (in normal matter not anti-matter) and it wouldn't even notice. Throw enough anti-matter into the sun and you will make a big explosion but you would need a LOT of anti-matter. To do what you are talking about you are going to need some exotic physics and some techno-babble. You're talking increasing or reducing the effect of gravity inside the star, or somehow changing the behavior of fusion, or introducing some sort of weird quantum state chain reaction. None of those things are possible using any physics we know about, but then neither is FTL travel so you can quite plausible use the FTL drive as a starting point and create some form of nova bomb. [Answer] ## A rapidly-deployable Dyson sphere Are those aliens on Omicron Persei 8 causing you grief? What better way to permanently deal with the problem than by *literally stealing their star*? Simply deploy a Dyson sphere around their solar system's star(s), and watch as their planet freezes! As a bonus, you get all the energy produced by the star(s) you just wrapped up, which can be used to create more Dyson spheres and power star-system-destroying superweapons. Soon, the entire galaxy will be under your command! [Answer] ## Option 1: Add mass. The more massive a star is, the faster it burns, and the sooner it dies. Add too much and it may go supernova, or even become a black hole. ## Option 2: Remove mass. Stars fuse atoms because they're so heavy they squash everything together. They squash because anything with mass has gravity. Removing mass from a star reduces the pressure on the atoms within it, lowering the rate of fusion, and cooling the whole darn thing down. ## Fine print. The problem is, both of these options require planets and planets worth of mass to have any sort of effect. If you're a galactic civilisation that's capable of moving that about in a quick time frame, you're just better off smashing planets into their planets. [Answer] # No. To my knowledge, the only really serious calculations regarding this scenario are in [an article by Alexander Bolonkin and Joseph Friedlander](http://www.scirp.org/journal/PaperInformation.aspx?PaperID=34277). It's currently cited in [the current highest-voted answer](https://worldbuilding.stackexchange.com/a/36121/627) as a feasibility study of the possibility of destroying the Sun by detonating a nuclear weapon in the Sun's atmosphere, inducing a self-supporting nuclear detonation wave that would subsequently propagate throughout the entire Sun, causing a catastrophic explosion. I think it's an excellent guide with which to show that this idea is *not at all* possible, contrary to the claims made. Given that, I'm going to critique its analysis, and therefore the scenario given. ## The setup Let's assume that someone has created a spaceship, placed a nuclear weapon on board, and sent it on a trajectory towards the Sun. They've timed it to detonate in the solar atmosphere; moreover, they've designed shielding that protect it from high temperatures and solar activity like flares and coronal mass ejections. Essentially, we can assume that the payload is delivered successfully and the detonation begins as desired. If a nuclear weapon was detonated in *any* environment, creating a self-sustaining blast wave, the wave would be supported by whatever fusion reactions are favored by the surrounding medium. In other words, the weapon itself doesn't dictate the type of nuclear reactions supporting the blast wave, and the most efficient ones will be chosen. This is something that was studied during the Manhattan project. The scientists were concerned that the first detonation of a nuclear weapon would initiate a self-supporting blast wave that would travel through the atmosphere and oceans, killing all life on the planet. It's a scary possibility, and naturally, it was modeled in a lot of detail. A number of papers were published on it over the years, including [*Ignition of the atmosphere with nuclear bombs*](https://fas.org/sgp/othergov/doe/lanl/docs1/00329010.pdf). In air, the reactions the physicists were most concerned about involved the fusion of two nitrogen atoms - certainly a possibility, as nitrogen is the most abundant component of the atmosphere. Even though the groups considered the most favorable conditions for sustaining such a blast wave, they found a runaway detonation impossible for reasonably powerful nuclear weapons. I'm sure [they thoroughly checked their calculations](https://xkcd.com/809/). The Sun is largely composed of hydrogen, ionized because of the high temperatures. It generates energy primarily via a form of the [proton-proton chain reaction](https://en.wikipedia.org/wiki/Proton%E2%80%93proton_chain_reaction) (p-p chain); much higher temperatures would be needed to use reactions found in more massive stars. In particular, a variant called the *p-p I branch* is dominant and most temperatures in the solar core. It's reasonable to expect that the same sort of reactions would occur immediately following the detonation of the weapon, provided the required temperatures (10-15 million Kelvin) could be achieved. ## Why would a nuclear weapon help? With the exception of the corona, the Sun's photosphere has a temperature of about 5800 K. The temperature increases further into the Sun, but with the exception of the core, conditions aren't extreme enough for nuclear fusion to proceed. Bolonkin claims that even in the core, temperatures are low enough that the p-p chain proceeds slowly - about 15 million Kelvin. He invokes something called the [*Coulomb barrier*](https://en.wikipedia.org/wiki/Coulomb_barrier) to support his point, claiming that a nuclear weapon could surmount it. The Coulomb barrier is an extremely well-studied phenomenon, because it's extremely important when fusion is on the verge of happening. Nuclei have a net positive charge, as they're composed of protons. Therefore, any two nuclei will repel each other if brought close together, via the electrostatic force - described by Coulomb's law, which you've probably talked about in an introductory physics course. This repulsion gets stronger the closer together the nuclei get, meaning that it's very, very hard to overcome the force. This is the Coulomb barrier. The Coulomb barrier is a problem - so big a problem, in fact, that stars shouldn't be able to avoid it. Stellar fusion would be impossible except at extremely high temperatures - [over 10 billion Kelvin](http://burro.cwru.edu/academics/Astr221/StarPhys/coulomb.html)! Fortunately, there's a way around it: quantum tunneling. [Quantum tunneling](https://en.wikipedia.org/wiki/Quantum_tunnelling) arises because a particle's position and momentum can never be known exactly, and there is always a probability that a particle will be in a given location. The wavefunction of the particle - a description of how likely it is to be in a certain state - shows that two protons have a probability of being arbitrarily close together, which would normally be forbidden by classical physics. Bolonkin ignores quantum tunneling, arguing that the merit of a nuclear weapon is that it could temporarily raise temperatures in a small region of the Sun. The higher the temperature, the more likely a particle is to move at higher speeds. Therefore, more protons would be likely to fuse. I've seen the same logic used elsewhere to justify using a nuclear weapon in this scenario. However, [the temperatures around a nuclear weapon will only rise to several tens of millions of Kelvin](https://hypertextbook.com/facts/1999/SimonFung.shtml) - extremely hot by most standards, but far too cool to help more particles overcome the Coulomb barrier. ## The stability conditions Bolonkin claims that in order for a detonation wave to continue propagating, it must travel faster than the [ion speed of sound](https://en.wikipedia.org/wiki/Plasma_parameters#Velocities). He eventually derives what he claims is the criterion for a successful, self-sustaining blast wave:1 $$n\tau>\frac{\gamma zk\_BT}{(\gamma^2-1)E\langle\sigma v\rangle}\tag{1}$$ where: * $n$ is the number density of particles. * $\tau$ is something equivalent to the confinement time * $\gamma$ is the [adiabatic index](https://en.wikipedia.org/wiki/Heat_capacity_ratio) * $k\_B$ is the Stefan-Boltzmann constant * $T$ is the temperature of the environment * $E$ is the energy of the reaction * $\langle\sigma v\rangle$ is the mean reaction rate - an average of the product of the collisional cross-section of a proton and the relative velocity of protons * $z$ is the charge of the nucleus divided by the fundamental charge. Bolonkin claims that his condition is superior to the [Lawson criterion](https://en.wikipedia.org/wiki/Lawson_criterion), which is commonly used in designs of nuclear fusion reactors to determine whether fusion can take place. It's usually derived from a perspective of energy loss: Can the reaction, in the given environment, produce more energy than it loses? The Lawson criterion is $$n\tau>\frac{12k\_BT}{E\langle\sigma v\rangle}\tag{2}$$ which is very similar. The authors seem to imply that Lawson's derivation is inapplicable in a star because, as they claim, there are no energy losses; in a nuclear reactor, on the other hand, energy can be lost to the walls and surrounding environment. Therefore, they conclude, their version is correct. Well, then let's see how much more favorable their condition is. Bolonkin says that $\gamma$ should be between 1.2 and 1.4, and that $z$ should be set to 1. In the cases where $\gamma=1.2$ and $\gamma=1.4$, we find that $$n\tau>\frac{2.73k\_BT}{E\langle\sigma v\rangle},\quad n\tau>\frac{1.46k\_BT}{E\langle\sigma v\rangle}$$ That's not a huge improvement - lower than Lawson's by a factor of 4 to 8, roughly. We shouldn't get too excited here. It's debatable as to whether *either* criterion holds, in fact, as Bolonkin failed to consider energy losses in the photosphere, where the detonation would originate. The upper layers of the Sun's atmosphere are *optically thin*, meaning that light can travel through them with relative ease. I'm concerned reasonable that, therefore, energy would be lost rather easily. Slightly more complex formulations of the Lawson criterion look at other sources of energy loss; Bolonkin's clearly does not. One form of energy loss that comes to mind is [thermal bremsstrahlung](https://en.wikipedia.org/wiki/Bremsstrahlung#Thermal_bremsstrahlung). Bremsstrahlung is radiation emitted when one charged particle is accelerated or decelerated by another. Given that after the detonation, we have hot ($\sim10^7$ Kelvin) plasma in an environment that may be optically thin to these x-rays, bremsstrahlung could be an efficient form of energy loss.2 I should note, of course, that the Lawson criterion is usually applied to nuclear reactors, not stars. Therefore, it seems strange that Bolonkin would want to compare his results to Lawson's at all. ## The thermostat effect The Sun is composed mostly of plasma - largely, as I said above, of hydrogen nuclei - protons! The gas obeys the [ideal gas law](https://en.wikipedia.org/wiki/Ideal_gas_law), hopefully another concept you've come across before. The ideal gas law is an *equation of state*, meaning that it relates several thermodynamic variables together. Although the law is usually formulated as $PV=nRT$, a sometimes-preferred form in astrophysics is $$P=nk\_BT\tag{3}$$ where $P$ is pressure, $n$ is number density, and $T$ is temperature. The ideal gas law should hold well in the outer layers, and should be a decent approximation in the core. The big criterion is that [the thermal energy be much larger than the energy of interactions between protons](https://physics.stackexchange.com/q/192007/56299), which holds in general. [The standard solar model](https://pubs.acs.org/doi/pdf/10.1021/ed066p826) confirms this; the ideal gas law's predictions largely agree. There are some pretty nice consequences of the ideal gas law. Let's say that temperature in a pocket of the Sun rises, thanks to the rate of nuclear reactions increasing. This should in turn speed up the reaction rate; I said before that higher temperatures are more beneficial to fusion. Well, according to the ideal gas law, if the temperature rises, then either the pressure increases or the density decreases. It turns out that we should expect $P$ to increase and $n$ to decrease simultaneously. A star supporting itself by nuclear fusion is in [hydrostatic equilibrium](https://en.wikipedia.org/wiki/Hydrostatic_equilibrium). The gas pressure trying to expand the star opposes the force of gravity trying to collapse the star. However, if the temperature rises, the pressure will increase. Suddenly, the star is out of equilibrium, and the net force on any layer will be upwards, away from the center. This lowers the density, which in turn lowers the reaction rate and the temperature, bringing the star to equilibrium again. This is sometimes informally referred to as [the solar thermostat](https://web.njit.edu/~gary/202/Lecture14.html). This [prevents runaway nuclear reactions](https://astronomy.stackexchange.com/q/12148/2153), for the most part. The quantity $\langle\sigma v\rangle$ is [often approximated as being a power law](http://www.astro.caltech.edu/~jlc/ay219_spring2010/nuclear_reactions_18april2010.pdf) in terms of temperature dependence. That is, $\langle\sigma v\rangle\propto T^\eta$, where $\eta$ is a constant. For the p-p chain, there is a small temperature dependence, relative to other reactions (like the CNO cycle). In particular, [we can say that $\eta=4$](http://eagle.phys.utk.edu/guidry/astro615/lectures/lecture_ch5.pdf).3 If we plug this into either version of the criterion, we find that $$n\tau>CT^{-3}$$ where $C$ is a constant depending on which criterion you've chosen. Therefore, at lower temperatures, $n\tau$ must be greater, making it harder and harder for fusion to occur as the temperature drops. Again, this assumes that both criteria are valid; even if they are, the risk of a runaway detonation is non-existent. ## Astronomical events It turns out we can look to the skies to think about naturally-occurring events that are similar to the scenario you describe. First, there are examples of solar activity, including [solar flares](https://en.wikipedia.org/wiki/Solar_flare) and [coronal mass ejections](https://en.wikipedia.org/wiki/Coronal_mass_ejection). The energy released in these events can range from $\sim10^{20}$ Joules to $\sim10^{25}$ Joules. However, the [Tsar Bomba](https://en.wikipedia.org/wiki/Tsar_Bomba) (the most powerful nuclear weapon ever detonated) released only $\sim10^{17}$ Joules. Given that solar flares regularly release thousands of times as much energy in the photosphere - the target region of detonation - without any catastrophic problems, I think we can consider the risk of detonation by nuclear weapon to be even lower. Moving on, consider [helium flashes](https://en.wikipedia.org/wiki/Helium_flash). These are believe to occur in low-mass red giants (less than 2 solar masses). As hydrogen fusion ceases in the core of a star (while continuing further out), the core falls out of hydrostatic equilibrium, and the star begins to contract. This raises temperatures until matter in the core becomes [degenerate](https://en.wikipedia.org/wiki/Degenerate_matter). Degenerate matter does *not* obey the ideal gas law,4 and so cannot fight back against rising temperatures. Eventually, runaway fusion begins via the [triple alpha process](https://en.wikipedia.org/wiki/Triple-alpha_process), at temperatures around 100 million Kelvin. However, even under such conditions, the matter soon becomes non-degenerate. Thermal pressure returns, the ideal gas law is applied, and the star is in hydrostatic equilibrium once more. Helium flashes are much more powerful than solar flares, coming in at around $\sim10^{41}$ Joules. You can read more about the instabilities involved [in these detailed slides](http://astro1.physics.utoledo.edu/~megeath/ph6820/lecture23_ph6820.pdf). The thermostat mechanism is *not* applicable in objects composed solely of degenerate matter, like white dwarfs. This often has dire consequences; if matter is transferred onto the surface of a white dwarf and it heats up, runaway fusion can occur, usually involving carbon and oxygen. The result is a [nova](https://en.wikipedia.org/wiki/Nova), which leaves much of the star intact, or a [Type Ia supernova](https://en.wikipedia.org/wiki/Type_Ia_supernova), which may destroy the white dwarf or turn it into a neutron star or black hole. Type Ia supernovae usually release $\sim10^{44}$ Joules of energy - although this is a byproduct of a successful detonation, not the cause of it. Numerical simulations have been done of the propagation of detonation waves through white dwarfs. One result is that detonations have the potential to turn into [deflagration waves](https://en.wikipedia.org/wiki/Deflagration), which are less catastrophic. This has been studied a lot in pure fluid dynamics, but it's interesting to know that instabilities can quench possible detonations in white dwarfs - I'll try to pull up an article on some examples. It makes me wonder whether, even if I'm wrong about everything above, if this hypothetical detonation could falter into a deflagration, therefore saving the Sun from destruction. However, even in extremely catastrophic situations, a non-degenerate star like the Sun can stabilize itself against runaway fusion reactions. A red giant could survive a helium flash, which at first seems extremely devastating. There's no way that a puny nuclear weapon could overcome the mighty thermostat effect. In short, if you're trying to blow up the Sun, I'd recommend turning your efforts elsewhere. Bolonkin and Friedlander are, simply put, wrong. --- ### Footnotes 1 His notation is non-standard and unclear, and include unnecessary terms for unit conversions. I've standardized them here for clarity, and fixed a typo or two he made. 2 The power radiated by thermal bremsstrahlung is proportional to $T^{1/2}$. 3 We call the case where $\eta=4$ weakly temperature dependent because some fusion reactions in slightly more massive stars involve $\eta=17$ or $\eta=20$! 4 White dwarfs and matter supported by [electron degeneracy](https://en.wikipedia.org/wiki/Electron_degeneracy_pressure) obey [one of two main equations of state](https://www.astro.umd.edu/~jph/A320_White_Dwarfs.pdf). For the ideal gas law, $P\propto\rho T$, where $\rho$ is density. White dwarfs obey $P\propto\rho^{5/3}$ (non-relativistic) or $P\propto\rho^{4/3}$ (relativistic), depending on the regime. In both cases, there is no temperature dependence. [Answer] If you have FTL transport in your fictional universe, you might be able to apply that to the problem. For example, if you use wormholes, open it up inside the star. If you can control the kind of energy needed for warp drive, you're lucky *not* to destroy a few nearby stars when inventing it! In fact, my joke answer of what GRB might be (before there was a solid consensus it was a mystery for a long time) is "That *was* a civilization trying to invent a warp drive". Maybe you can use time travel and prevent the star from ever forming, or setting up another on a collision course way in the past. Or just make the star vanish into the 6th dimension. Some Sci-Fi uses the idea of [“strange matter” being more stable than normal stuff](https://en.wikipedia.org/wiki/Strangelet#Debate_about_the_strange_matter_hypothesis), such that if a tiny sample of strange matter formed it would convert anything it came into contact with. That would do the job here, if you got the initial sample to fall in rather than being blown away. In Hogan's *Giants* series, the space ship technology (pre-FTL) uses black holes spinning in a ring to generate space warps to make a ship move at relativistic speeds by "falling" into the dent it makes (not a FTL space warp). A variation of that technology was used in a number of probes arranged around a star in an attempt to "adjust" it, and the experiment "did not work" in a violent manner. In Stephen Baxter's universe, dark-matter life forms are making all the stars age prematurely. So what if there was some dark-dark-matter life form or extradimensional life form that had bad effects on a star, and you *infected* the star in question? --- Of course, depending on the nature of the story the mechanism could be Clarke-tech (that is, might as well be magic). I had an idea for a story (never developed) where aliens give a gift to the humans: a little tadpole-shaped thingie that can destroy any body, whether asteroid or planet. It's in a jar that's very difficult to open and would require a concerned engineering effort to accomplish. But once opened, just drop the tadpole onto the “body that would cause a navigational hazard” and it starts eating away at it with the mass essentially just vanishing. The story would be about how humans react to the existence of such a thing, and how it works in detail is never explained and does not need to be. The people in the story would *lampshade* the mystery (they wish *they* knew; they speculate) but the details don't matter to the story. So what would happen if you dropped it into the sun? Maybe it would work. It's worth a try, I suppose. [Answer] I know when iron absorbs a lot of the energy created by the nuclear fusion within stars so if you could put enough iron (you'd need a lot) in a star, it could theoretically "kill" it, as it possibly can not gain any energy from the iron. [](https://i.stack.imgur.com/EWfZwm.png) [Answer] First - examine "prior art" or subject matter. **[0] Warp drive in your universe.** After you complete outline of technologies, you may find that Star Trek on screen used warp drive to disturb star surface (e.g. to destroy dominion shipyards) by causing a flare. Ian Douglas / William Keith in "Galactic Corps" described species called Eulers, which used "trigger ships" (small capsules traveling at warp) to punch through the star, cause a shockwave which in turn resulted in star turning nova. **[1]** As Star Trek TNG "Q" put it "simple - **change the gravitational constant of the universe**". This was explored in details in Issac Asimov's "Gods Themselves..." - Constants in Question were beautifully described by scientist **Martin Reese in absolutely must-read "Just Six Numbers"**. Certain invention called electron pump allowed two universes to generate free energy by exploiting subtle differences in nuclear force strength. However, it turned out that these constants started drifting and equalizing between universes, causing slow, but meaningful change in star behaviour. [2] There's option explored in Andromeda (TV series) as regular weapon (WMD by any means) and Stargate SG-1 (jury rigged) - "nova bombs" and shielded stargate dropped into the star. Both caused disturbing balance between radiation pressure and gravity in main sequence star. In first case, it was miniature "white hole" generated using combination of negative energy and exotic matter in second...well..just active stargate, sucking stellar mass. [3] SG-1 in other episode beautifully told another concept: **"poisoning the star" by introducing heavy elements into the core.** Note: once stars star to create iron, which can't be fused further without significant energy input, their fate is sealed. Question is: how much is needed. [4] Decade or so back, Scientific American published article about simulation regarding **rouge white dwarf star hitting the Sun.** Note, that recent discovery of gravitational waves confirmed that black hole systems may exist - and that includes such, which will give stars or other black holes effect of gravitational "slingshot". [5] Again "Galactic Corps" - quantum mechanics. In general, if you could map wave functions of elementary particles that compose the star, you could alter them - and possibly, the physical parameters of respective particles. Even just "sniffing it out of existance". **[6] Introduce q-ball into the star** as in movie "Sunshine". Again, use quantum mechanics to disturb fusion within the star. [7] Brute force: find a small black hole. Throw huge star at it. Create accretion disk and polar jet aimed at given system :) problem is, that's overly excessive (why not smack original star) and limits damage to speed of light. **[8] Stars usually spin**. There exist a neutron star (or magnetar) which is definitely too heavy and should collapse into black hole long time ago, but - as suggested in other answer - it is stabilized, presumably by fine balance between excess of mass and ultra-fast rotation. If you could arrest some of the spin... **[9] LHC-like scenario** create artificial singularity, project into the star, let it do the and eat it. [Answer] Pump into the star half as much oxygen as the star has hydrogen\*. That will cause the star to burn rather than fuse. \* May require a large oxygen supply. [Answer] Peter F Hamilton has introduced a device called "hawking m-sink", which is, if I remember correctly, a small amount of [Neutronium](https://en.wikipedia.org/wiki/Neutronium), which essentially creates a miniature black hole that consumes whatever is in its reach up to a limit (I think). In the novel in question ("The Temporal Void"), a planet has been destroyed this way. However, the planet has not been consumed completely, but since the core has been consumed it broke apart before the m-sink could devoure the rest. A similar device could work on a sun (maybe even better, since a sun or gas giant may be more... fluid, though it probably depends on the amount of handwavium you want to employ. EDIT: To clarify the purpose of this post and the use of Neutronium: The name "neutronium" is most commonly used to describe the exotic matter state in the core of neutron stars, which have a collapsed matter state due to the immense gravitational pressure of the neutron star. Neutron stars are the most dense celestial bodies known to exist apart from black holes. The books dont describe in detail what exactly happens inside the hawking m-sink, but in essence the device has something similar to an event horizon, which collects matter in order to increase the radius of the m-sink, thus allowing it to absorb matter even faster, until a threshold is reached. After this point, I'm not sure what happens. I think the most of the absorbed matter is expelled in a similar manner that pre-neutron stars shed their hull going supernova - just in very small. I will update this as soon as I find the relevant passage in the book. A similar device has been employed in another novel by the same author, "The Neutronium Alchemist" Take this as an addition to other good answers. [Answer] Well the main issue with killing a star via supernova is that supernovas require a [massive star.](https://en.wikipedia.org/wiki/Stellar_mass) So You couldn't, for example, destroy Sol without upping its mass fairly considerably. Dark matter might help with that, but dark matter is weird stuff (Neptune would have been considered "dark matter" til it was discovered due to the fact that it had significant gravity, but nobody had seen the damn thing). Anyway, say you now have a Sol that is, by hook or by crook, at ~1.4 Solar masses. The next thing you need to do is speed up its fusion reaction so that it explodes due to core collapse. There are a few ways to imagine that, but the most interesting to me is the [relativistic baseball](https://what-if.xkcd.com/1/). Get a sizable thing traveling fast enough that the star's atoms can't get out of the way and accelerates fusion. This may take more than one shot. The fun way to do that would be to abuse warp technology and reference frames. The thing that is moving FTL only has to appear to be doing so in the star's reference frame. To the object, it may appear to be traveling at a reasonable speed but over a decreased distance. [Answer] If you have FTL perhaps you could try ramming target stars with FTL starhips. Depending on how FTL works that might explode stars. I personally hate the idea of destroying planets and stars billions of years old and which may be useful for billions of years in the future merely for victory in some ephemeral conflict. If all advanced civilizations do that habitable planets will be used up far faster than they are created and the galaxy will run out of habitable worlds in a cosmically short time. [Answer] What ever method you choose, make sure that the method for destroying the star ties in with something else in the story that is NOT about destroying the star. For example, if the "bomb" is small enough to fit in a hand, then it could also be a (misunderstood) child's toy that figures in the story in a plot line that is not directly tied into the plot line in which the star is destroyed. But of course, when the star is destroyed with the child's toy, then this provides an opportunity to tie the two otherwise independent plot lines together. Oh. I think I'm going to cry. :) Oh. That doesn't explain HOW to destroy the star. How's this: The star's destruction was assured when, a long time ago, the star was engineered (the engineering marvel remains unexplained) to remain stable in spite of being so supermassive that it should have immediately collapsed into a black hole. But -- thanks to the engineers who stabilized it -- it's a star. The also engineered a "thermostat" that needs an adjustment every 150 Million years. It got lost. It was recovered. It became a toy. Somebody figured it out and used it to destabilize the star. It collapsed. Ta Da!... Oh darn. That's not "a bomb" [Answer] Your already using some "tech" that is still not possible. So here are a few futurish options. Warp the star. You have warp drive technology. This compresses space/time in front of you and expands it behind you. Do this to a star but stop the process with the start partly compressed and partly expanded. Negative Mass Bomb- Just like it sounds, send a bomb that explodes with negative mass. This should theoretically tear a hole in space and suck in the star. Move the Star - Who says you actually have to blow it up? If the end game is to destroy the planets in the system, just move the star. Use some sort of ultra dense (had more gravity then the star) material that is protected by some anti gravity shielding. Then all you have to do is launch it near the star. It either will suck in the star or pull it into an orbit, thus disturbing the orbit of the bodies around it. If you want to go Star Trek meta: Omega particle. If memory serves me right, only a couple are needed to restart the universe. [Answer] **Focused Graviton Beams** So thanks to the [LIGO gravitational detector](https://en.wikipedia.org/wiki/LIGO) and others that are being built we can start to test out our theories about gravitational waves, gravity, and other things. Extrapolate forward a while and we finally find the [graviton particle](https://en.wikipedia.org/wiki/Graviton). This lets us really start playing around with gravity, learning how to manipulate it, generate it, reverse it, etc. An interesting thing about stars is that there is a lot of inward pressure from gravity trying to squeeze them down really small. At the same time there is a lot of outward pressure from fusion keeping that from happening, meaning that the star is in a kind of balancing act. If you were able to focus gravity into a tight, strong beam you could potentially disrupt that balance, causing a chain reaction and kill the star. [Answer] I think, that implementing small black hole inside the star should eat it from inside eventually. Depends how big black hole you can transport too. Also depends, how your FTL works (some works on making "shortcut" between two points in space), it could be possible to make shortcut from the sun core to the planet in question (if FLT engine is requested to be at one end of the shortcut, it could be on the planet surface or near to it) Locals would probably not like the idea, so the Item need would to be transported to low orbit by FTL too. Imagine ship making the FLT shortcut from your system to theirs, near the planet, then prepare another from that orbit to the sun core (and do not use it, but keep it as big for as long it could last) - it would do big damage to the planet by many ways - the radiation inside sun is massive and you rare projecting it on the planet. the planet will suffer big slap wave, sipping atmosphere to the sun by gravity and having it replaced by some sun material exploding to hole with less density. Even if such ship and FTL tunnel would be destroyed nearly instantly, the shock wave could kill everything on the planet surface (and near both ways - underground bunkers as well as orbital satellites. Also vulcanic activity would erupt on big scale. Bonus is, that you can later use that dead body of planet as valuable source, or even make there colony in relatively good distance from sun and with a large planetary body to use and terraforming. [Answer] Threaten to violate causality. Some have speculated that there is a need for a "cosmic censorship principle" to prevent the creation of closed time like curves and causal paradoxes. So start to build a time machine in or near your enemy's solar system and expect that system's star to "inexplicably" go nova. That big ball of plasma will very effectively mask any small local paradox that happened a few minutes earlier. Beware. Do not ignore the minority opinion that there is a cosmic morality principle as well. If so it is *your* solar system that may be destroyed as soon as your evil plan is placed in irrevocable motion. Warning: this plot has been used. I read the story many years ago. Can't remember author or title. [Answer] Create a **black hole storage container** ('bomb') and open it in/near the sun. It will suck in the entire sun with a flash of radiation coming off the infalling matter. The loss of sunlight will be devastating to that solar system population if the flash does not kill them first. Given the relatively small size of the sun, the black hole does not have to be that big. Now, how you are going to contain that black hole inside the container? Easy, use some sort of 'black hole plasma' contained in magnetic or gravitational wave fields (give these a nice name like *Feynman fields*) and that are kept stable by evaporating Hawking radiation. When reaching the target, switch off this containing field. [Answer] My answer would be Massively scaled stellar mining rig/barge/station (Mining star matter) so fast that leave it for a day or two you'll notice changes happening in the star... But we can go better... You have warp technology right so why not warp stellar matter using hawking radiation(black hole) to another enemy of yours? suck the star of its matter and throw that matter to your enemy! Not only it could collapse a star since it will be missing alot of its mass since you are warping it away but hit another enemy as well with it! Imagine a star being pulled apart and its mass being sent to your enemies! It will not go supernova(as far as i know) but you can be sure that they got nothing on your stellar sized plasma flame thrower... Since this is a galactic strategic weapon price shouldn't be an issue constructing a warp ring enough to engulf atleast 10% of the star or 1% for that matter depending on how fast you want the star gone or your enemy gone... take your pick! [Answer] A surprisingly large amount of over engineering has been proposed. Do armies destroy a mountain that the enemy has camped on or just the camp? Warfare tends to follow the principle of using no more than necessary? Why destroy the star when you can make the planet just as uninhabitable with a few nukes or an asteroid strike? Some of the consequences are hopelessly naive. If you move a star from your enemies planet and they are incapable of moving the planet, moving to another planet, moving to a space station or setting up a fusion reactor and swarm of lights in orbit, then you are far more technologically advanced and you cannot hope to win. (unless your attacks use 1000 000 times more energy than it takes them to stop the attack) Why are they fighting, for habitable planets, whats habitable to one alien species may not be to another. Why don't they grab an asteroid and live in space colonies? The asteroid belt provides enough raw materials to make 1000's of times the earths area in space habitats, no implausible physics required and everything you can get on a planet can be easily provided. (The ISS already has many of the features, with spinning for gravity and radiation shielding just being slightly too heavy0 [Answer] Just about the simplest solution I can think of is using wave forms. Flame from the sun or otherwise is the vibration of molecules.by generating a force wave capable of stopping this vibration essentially freezing the star in place could be all It would take.. Be it with lasers tractorbeams or a mechanical trap pulsating expansions and contractions targeted at alligning the mass into a stable non burning mass. To add a little clarity as commenter did seem to have missed the key to the proposition,3d wave forms are a new science in function where scientists are using speakers to manipulate matter in a 3 dimensional area. levitating small Every day objects with no more than sound waves. Upscaling this technology to calculate the estimated location of the particles composing the sun,a frequency targeted at moving the particles into a state where they would align and sit in a state of rest to stop the chain reaction of the sun's burn. More like using a pulse grenade to put out a house that was on fire. The burst would not equal the total mass force of the house but merely vibrate the air so as to flash off the flame. ]

[Question] [ In most fantasy settings and worlds, we have different races like Demons, Elves , Fairies, Angels and so on and on. Most of them usually have longer lifespans than humans and while it might seem like a dream come true to be able to live for thousands of years, I'm not sure that all that glitters is gold. So if say we had elves that have an average lifespan of 5000 years, they are slightly stronger (includes things like agility and reaction time) than the average human by about 1.5 times. **What are some plausible disadvantages for a long living race?** Some cons I have thought of would be having a low birth rate and how chronic disease would make life hell. Other than that the technology level is around medieval era but their medicines are about 19–20th century standard, they had a lot of time to make medicines with the flora in the forest they live in. [Answer] First off, **repopulation**. There are two possibilities - either the elves have a birth rate similar to humans or they have a birth rate vastly reduced to match their lifespan. In the former case, the elves would become vastly overpopulated very, very quickly, with a death rate that's negligible next to their birth rate. Such a species could conceivably become extraordinarily warlike or prone to risky behaviour, just to artificially increase their death rate. In the latter case, elves would be incredibly vulnerable to attrition tactics - any attacking force willing to wage war for a couple of hundred years could deplete the elves' population before the next generation matured. Likewise, any long-term natural disaster - like a plague - could wipe out the elves when humans would have scraped by. Second, **stagnation**. Humans already have this problem - as we get older, we get to be set in our ways, resulting in a significant portion of the population being locked in values and ideas decades out of date. With elves, this would become vastly worse - the three-thousand-year-old Queen of the Elves might have difficulty adjusting to any technology invented less than two thousand years ago, and would likely insist on tactics that worked a thousand years ago. Third, **memory**. A species that lives a hundred times longer than a human has a hundred times more to remember. Again, we have two options - either the elves have no better memory than a human, or their memories are expanded to suit their expanded lifespan. In the first case, the elves would be unlikely to remember clearly anything more than a hundred years back, and so would forget vast swathes of their adult lives, with obvious consequences. In the second case, they are storing a vast amount of data - keeping it all straight, and bringing it to mind in a timely manner, might be difficult. It might even turn into a sort of dementia - with thousands of years of memories in your head, losing track of what year it is would be easy. Fourth, **genetics**. For humans, influenza evolves so quickly relative to our lifespan that we can't make a long-term vaccine. For elves, virtually every disease would evolve that quickly relative to their lifespan. With the gene pool taking so long to change - because the next generation is so slow to come - they'd be hit with a plague on the scale of the Spanish Influenza every century or so, if not more often. And as pointed out above, getting hit with a plague is *bad news* for a species that repopulates slowly. [Answer] A major disadvantage would be a **greatly increased risk of resource depletion.** Another would be **the risks faced by these creatures before they can reproduce.** At its core, **the purpose of life is to ensure the continuation of the species.** Life begets life. Hence, if you want a species to have an exceptionally long life span, then there should be something about that longer lifespan which has, on evolutionary timescales (which work on generations, not years), helped ensure the survival of the species, and ideally an individual's own offspring. In evolutionary terms, parents' responsibility to help safeguard the survival of their offspring lasts until their offspring has matured to the point of having offspring of their own. We see this pattern time and again in nature, particularly in species that have fewer offspring but tend to them: offspring leaves their parents once they are near or at sexual maturity, not before. Every individual who is alive, including those who are unable (too young, too old, sick or infirm) to defend themselves and to reproduce, requires sustenance. You mention medicine, but that's the last thing you should be concerned about, because frankly, especially with the technology level you seem to have in mind, keeping sick and infirm individuals alive would be a luxury, not something to be taken for granted. If their technology level is "around medieval level", they are going to have serious challenges growing or catching sufficient food. Each individual will require, irrespective of their preferred food source, far more biomass to sustain themselves for 5,000 years than for 50 years. This presents a number of challenges especially because in the era you are comparing against, **life for the vast majority of humans was already at a sustenance level.** Particularly if combined with a greatly reduced birth rate, you will have far more individuals who are at a stage of their life where they are not reproducing or tending to offspring and thus, from an evolutionary perspective, are not productive members of their species. You can in principle do something like make their life cycle such that they don't reproduce until age 3,000 years, but then you have to explain how they got to that point. **What was the advantage to having one's first offspring, on average, at age 3,000 years instead of at age 3 years or 30 years?** Every year you add to the age when they have offspring is a year that comes with the risk of debilitating injuries, illness, famine, perhaps war. Parents who get offspring that reproduce later would have a greater risk of not having any great-offspring. If anything, there would seem to be an evolutionary pressure to reproduce *earlier* rather than later, but there is a natural limit to how early it is reasonable for a complex organism to reproduce. In order to as much as *maintain* a population size, on average, each pair needs to have two offspring who survive long enough to have offspring of their own. [Answer] Can I mention **Boredom?** As someone's life goes on, they might arrive at the point of having done everything, and seen everything they might be interested in. Apart from the little news from time to time, life may become void and dull, leading them to retire in apathy. I know this could also be called Stagnation, but instead of the S. of ideas mentioned by Reese, this would be the one of an entire society not knowing what to do. *"What you want to do?" asked the High Queen of Arboria* *"I don't know, what YOU wanna do?" answered the Supreme Priestess* *"I don't know.."* [Answer] Living memory is a two edged sword. Sure they have the wisdom of ages but they also have the bigotry of ages. They remember that your great great great granddad still owes them money. Imagine a grudge that lasts as long as some religions. Set in their ways just doesn't begin to cover it. They need the young to drag them kicking and screaming into the future. Now you humans get off my lawn! [Answer] A longer life also implies a longer reproductive cycle. A longer reproductive cycle means the species will evolve much slower. That will make it more vulnerable to gradual environmental changes and generally hamper its development. When there is a new ice age which drastically lowers temperatures for a thousand years, 80% of humanity might get wiped out at first, but the most cold-resistant humans will survive, procreate and pass their cold-resistance genes on to the next generation. When the ice age is over, they will have adapted and get out of it with strong numbers. But the elves will not be so lucky. Their longer reproduction cycle means that anyone who dies can not be replaced so easily and it will take far longer for the cold-resistance genes to procreate through the population. At the end of the ice age they will have become almost extinct. When you have a long life *without* a long reproductive cycle, you will have a different problem: Overpopulation. Too many people get born but not enough old people die and keep consuming resources. But this affects the survival of the whole species, not so much the individual. When you compare an average middle-aged elf (300 years old) to an average middle-aged human (30 years old), the elf has the advantage that she had far more time to acquire skills and knowledge. You could counter that by making the species which live longer more forgetful. The elf *might* have been a masterful fletcher 100 years ago and a great warrior 200 years ago, but now barely remembers those times and forgot all of the skills she learned. Now she is no match for a human who acquired these skills just decades ago. [Answer] A central theme of [The Queendom of Sol](https://en.m.wikipedia.org/wiki/The_Queendom_of_Sol) novels is how children can’t take their place in society. The king and queen live forever so the crown prince will be the prince forever and never take over. Less obviously the same is true for any career: the student and protégé will never move on to have his own place in the field. In later novels, the main theme concerned overpopulation and resource depletion. [Answer] The only way to really understand what the potential is for extreme longevity (both advantages as well as disadvantages) is to consider the human factors involved. I'm using the term Human Factors loosely here, but one might glean something from the definition itself. > > In industry, human factors (also known as ergonomics) is the study of how humans behave physically and psychologically in relation to particular environments, products, or services. > > > <http://searchsoa.techtarget.com/definition/human-factors> Excluding the products and services part, what it boils down to is psychology mostly, that is, assuming we can, for the majority of the time spans under consideration, rule out debilitating factors such as chronic disease and lack of mobility. In other words we may gain entry into the question by considering the limited case of perfectly healthy individuals living for a very long time. So with that out of the way, what can be said of long term human/humanoid existence when health is not an issue? Let's assume as well that mental health is not an issue. One can possibly imagine several motivating factors related to varying interests for accomplishing things with the available time, but really the two basic ones that seem relevant are. * realizing personal or professional goals * improving the quality of life for oneself or others Now, considering that medicine is 19/20th century and mental health may be an issue, we must also consider the following factors which may lead to conflict: * acquiring medical care/herbs where supplies may be limited (this applies generally as well to any conceivable needs) * despair, anger or otherwise negative emotions (generally mental health)‡ ‡ We have often heard that folks have a tendency to become cynical as they age. I myself am on the cusp of middle age and can see the truth in that. I have often experienced despair and anger at human behaviors and actions, in myself and others, which to me (on second thought in the case where I am culpable) seem to be nonsense, ill formed, silly, unwise, stupid. The older one gets, the easier it seems to be to spot such behaviors. This can lead to despair and anger in individuals who do not actively maintain a healthy mental profile. Particularly in those who seek less social interaction. So to compare and contrast the two—the former seeming all positive, the latter seemingly the inverse of that—it's not hard to see that both are in fact the same. Realizing goals requires resources and effort, whether the goal is professional such as perfecting ones craft or elevating and maintaining ones reputation, or personal, such as feeling better or living longer. To compress the subject even more, quality of life is just another goal whether one finds reward indirectly by improving the quality of the lives of others, or directly by attempting to improve the quality of ones own life. So now that we've formulated a very broad and general context in which we find the longevity question, it makes sense to point out that goal seeking is the dominating factor that drives our lives forward. And how we address those goals, and more deeply how we address the goal forming process itself, determines what the positive and negative aspects of life will be. And I'm going to go out on a limb and suggest that this is true regardless of the amount of time involved. ☺ Now back to the human factors definition. Excluding again the two extraneous objects I mentioned before, the third stands out, and that is "how humans behave […] in relation to **particular environments**" So to give an inference as to how humans behave and what they may experience in your particular environment, I would suggest that they go about in the usual way as medieval citizens/subjects do and experience all of the positive things as well as the negative things that medieval citizens/subjects experience, but for longer. If that experience is bad, then presumably having that experience for a very long time is worse, but it could only be hardening. Keep in mind as well that we do grow accustomed to things and we even learn to rise above situations on occasion. Wisdom that comes with experience would seem to aid in that process. To actually answer the question as to the negative aspects of extreme longevity, particularly in medieval times, I would say that it probably starts off bad for most subjects (as Michael Kjörling points out), then gets worse, then much worse, then fades into normal over thousands of years perhaps, but possibly only a few centuries of replay will suffice to confirm what "normal" is—unless the person, the core of the living body, chooses to step out of the mental constraints of the world. And perhaps by breaking rules or side stepping expectations that person may suffer physically or even mentally, but it would seem that such a thing is short lived and of little consequence compared to centuries of inner nothingness. However, most people are as helpless to choose as they are to determine the length of their lifespan. This is perhaps as true for those in power as it is for those begging for scraps. The only thing left is whether the suckiness of life is worse than the consequences of making a choice and living with it. [Answer] There is an actual thing that people haven't considered yet, and that is that people don't want to die very much. Well, that seems obvious, but it has some implications for a longer lived race. Let's pretend that humans are in the middle, and we have a very short lived race (like the Salarians in Mass Effect, who live until they're 40), and then your elves. We take 3 smart people, one from each species, and ask them a question: Would you drive a car to work, assuming that traffic was like the US of A, in 2014? Well, according to [The Odds of Dying](http://www.livescience.com/3780-odds-dying.html), 2.5 per 100,000 drivers died in the US in 2014. WARNING: The math here is fudged and not 100% correct. It's merely correct-ish. If you're a salarian, you live 40 years, so taking that kind of odds for 40 years is about 40\*2.5 = 1 in 1000 odds if you drive from the day you were born until you die. If you're a human, you live 80 years, so you have 2 in 1000 odds. If you're an elf, you live 10 000 years, so your odds are 1 in 4. The type of elf that takes that kind of insane risk, to go out and drive in traffic in the US in 2014, seems to have a rather risky life, doesn't he? Basically every risk assessment for an elf will make things seem much more dangerous, because your threshold for "stupid stuff that will kill me before I'm 25% done with my life" is so much lower than for humans and salarians. Therefore any elf that wants to stick around for a longer time, and have more children, and thus more genes in the wider population, will be careful and conservative in his or her outlook on the world. That's just how biology works. [Answer] 1)It will need to sleep longer to save more memories otherwise every time one of their brain cells get's replaced they lose a lot of their life-worth memories forever. 2)if it has slow reproduction then each individual needs a system to increase the stress their receive during life so to make mutations happen faster, this will help each individual survive to new difficulties each time but will also increase the risk of cancer(cancer can be biologically prevented with some immunity systems in some animals) 3)In case it has normal/fast reproduction they have a lot of over-population problems 4)Cells poop, if they don't have an internal system that cleans the poop of each individual cell then the Elves will live literal hell after the first 100-120 years of life. 5)The more they live the strongest the fear of death will become, usually people build their phobia of the eternal oblivion during youth when their teen age is ending and lose it only when they are old and realize nothing can save them anyway. A race that lives 5000 years will have at least 4900 years to let their phobia of death become stronger each year,month and day... they will probably need a lot of psychiatrists. 6)Over time they will lose empathy to other species, young elves will learn to not affectionate to humans or other short lived creatures to not suffer when they die.The Life of one Elf is enough to experience the death of 60 humans,Imagine how could you feel after your friends died all one after another while you outlive all of them. [Answer] # Stewards of the Stagnant Planet Perhaps the long-living species have already experienced problems like overpopulation, resource depletion, infectious disease, and so on. Their technology/magic has allowed them to rid themselves or even the world of disease. Their experience with resource depletion has taught them to view themselves as stewards of the planet. Because they live long and healthy lives, there isn't the same hustle to work all the time and expect to live in luxury. Perhaps they have come to accept a simple form of life through art and meditation. It is worth noting that many European colonists in the Americas fled the work-to-the-bone colonial cultures to live with the Native Americans, and when they were "rescued" by their fellow colonists, they left at first chance to live with the natives again. So you might not have television, radio, the internet, and so on...but is that so bad? Or... # Lonely Galactic Explorers Borrowing from the Asari from *Mass Effect*, this species uses its immense lifespan to develop technological leaps that allow them to travel the galaxy. However, most other species have lifespans that are at most a tenth of their own, and so they are universally distrusted. Even though they have so much to offer in trade, art, and science, nobody will trade with them, and any conquering only adds to their image of an evil genetic elite. It would truly be a lonely existence to know that there is so much intelligent life in the galaxy, but it wants absolutely nothing to do with you. [Answer] For a creature to have a lifespan of 5000 years on average, it needs to be far more than 1.5 times as strong/fast/smart as a human. Accidental death rates in modern western societies is .04% with modern technology, safety and medicine. If that was the only thing that killed you, you'd have an average lifespan of only 2500 years. So the first step is to generate a mechanism for them to actually have an average lifespan of 5000 years. As we want to lean fantasy (these are elves), and elves live in trees, what I'd do is make the elves you see just a mobile appendage of some stationary, long-lived creature, like a tree. An elf-tree gives birth to elves, implanted with memories, which wander the world, tend the forest, and return to dump memories and be reborn. These elf-bodies could have a typical lifespan of 10-30 years, but the elf itself (its tree) could live for millenia. If the elf-body dies, it can grow a new one; it loses any memories collected by the elf-body that died, so that is to be avoided, but it is not fatal. The surface protrusion of this plant could just be the flowering body, protecting it from forest fires and easy death (more like a fungus with a mushroom). Elf-bodies are the elf-tree's seeds. They could settle down and grow a new elf-tree in a suitable spot. They could also be used as a form of information exchange, where an elf-body from one tree joins another, passing knowledge on to it. If an elf-tree's "tree" is just the flowering body of an undergrown fungus-type creature, it could have an extremely large body. Some old elves might be the size of entire forests (like some plants are in our world), and have the ability to spawn an army of elf-body-siblings in an emergency. Such a civilization would be quite alien to ours. The parts we interact with -- the elf-bodies, or even the elf-homes built up around elf-trees -- would be like bacteria interacting with our skin or immune system. Each elf-body is fully intelligent, but knows its immortality and rebirth is part and parcel of the elf-tree, and it remembers things from millenia ago (that where implanted in its fresh body). These creatures could be vulnerable to pathogens or parasites. The elf-bodies might have a full time job keeping some kind of parasite-beatle from killing elves, for example. An invading army could burn the forest down and poison the elf itself with salt or some other chemical: their difficulty moving leaves them vulnerable. Adventurer elf-bodies, the ones that are sent out to gather experiences, would be selected for being very reckless. They are, in a sense, disposible if expensive: the chance of death could easily be worth bringing back new interesting experiences. The motivations of an elf-body would be highly alien to humans. Rogue elf-bodies, who aren't returning to the tree, could be a problem. And, like cancer cells in humans, rogue elf-bodies could learn how to reproduce and cause problems. For worldbuilding purposes, humans might actually be an old cancer strain of elf-bodies. The remaining elves have figured out ways to keep the cancer away from their lands. Occasionally the elf-bodies and the humans interbreed, creating half-elves who grow like humans but may be capable of forming union with an elf-tree. [Answer] ## Note: a solely biological approach comes here. Well, one's for sure: evolution is slower. At least if we want to avert another issue: overpopulation. There are two possibilities in regards of reproduction: either said race produce a lot of offsprings in a lifetime, or a few. Of course, the former case in a long lifespan may imply *really many*, while latter don't. Said race would be extinct quite quickly (or at least drop huge in population size frequently) with too many offsprings during a too long lifespan. *Note that the exact amount of both too many and too long are to be interpreted specifically within your world.* There are various reasons for it: individuals would fight over **everything** scarce: * territory and/or shelter, * food and/or other key resources, * the right to reproduce, * the right for leadership (wolves do so), ...and so on. On the other hand, few offsprings mean that the effects of environmental changes appear at a much slower rate. This also might lead to extinction if said changes are quicker than the ability of the race to accommodate to it. A long lifespan might change certain properties of a member of the race in a more drastic way - but it's limited to the properties that *can* be changed. For example, though I'm not sure: whatever you do, your vision as a human won't be sharper during the decades - You might be more muscular, though. [Answer] The heartache from lost loved ones. My grandfather lived until his 90s. At that age, it wasn't his friends who he was reading about in the obituaries, it was his *friends' children*. Sure, he had his family, but nobody was his peer anymore-- he didn't have anyone who lived through the same events, the same music, same sports, same history. He was alone. Similarly, if a species is immortal but not invincible, they are still going to lose loved ones. Over the ages, the number of loved ones they lose will pile up. If their psychology is similar to humans, such losses will begin to weight on the psyche at some point. [Answer] I don't know about elves, but the greenland shark is supposed to grow 400 ys old, becoming fertile at 150 or so. How he does it? Taking it *very slowly*, in the *cold*. [Answer] In addition to all of the above: Boredom. For example in Ian Banks' *Culture* series humans can live as long as they want to, really, but most choose to either die after several hundred years or after a long life to be put into storage and awakened when something interesting happens. Ngaroe QiRia has lived for *thousands* of years (no-one is completely sure) and staves off boredom by immersing himself in other cultures sometimes undergoing a species change to do so. To get around finite memory, he shards of parts of his memory into vessels that can be kept stashed for later retrieval. [Answer] One potential downside: inability to adapt culturally. In [*The Structure of Scientific Revolutions*](https://en.wikipedia.org/wiki/The_Structure_of_Scientific_Revolutions), Kuhn argues that major revolutions in science didn't come about on the basis of evidence, but rather it was adopted by a new generation, and the old guard, who refused to believe, just ended up dying out. Kuhn calls this process a "paradigm shift", when the fundamental beliefs a society holds change wholesale, instead of just steady increments of fleshing out details. Without the turnover of generations, the society is unable to undergo paradigm shifts and adapt to new information or situations. Unless, of course, the psychology of these creatures are radically different from human beings. There were respected physicists in the day who were criticizing general relativity, but the last one died in the 60s, IIRC. Nowadays, there is no one (save cranks) who doesn't buy the theory. They all grew up with it. Related: <https://www.quora.com/Who-were-the-most-famous-scientists-who-opposed-the-theory-of-relativity> [Answer] **Infant mortality** (Disclaimer: I'm assuming that "average life span" is referring to maximum age, not to a literal and statistical 'average' taking in to account every individual in the population. In other words, I'm using a definition more like "average age of death, when death is a result of old age", which I believe captures the spirit of the question, if not it's literal interpretation) Many answers use evolutionary pressures as justification, but use only 2 possible schemes, high or low birth rates, yielding 2 possible (main) issues, overpopulation or extinction risk. There's at least one more option that I think would not only satisfy evolution, but also avoid both of those issues, while still causing a horrible situation for any race with human-like levels of compassion in the average individual: High child-mortality rates. (I feel that 'why' the rate is high is outside the scope of the question, so I won't attempt an explanation of that part, speculate or handwave as needed to justify it) High reproduction rates allows for plenty of chance for some individuals of the newer generations to be able to cope with whatever natural evolutionary influences present themselves. High mortality rates anywhere between birth and reproductive maturity, for whatever reason, will prevent the overpopulation issue. Add in a very strong biological urge to reproduce while the individual is still able, and you end up with parents that have to grieve for thousands of years for hundreds or thousands of children that didn't survive to adulthood. I can't imagine much worse 'disadvantages' than that. [Answer] Almost no elf will have any initiative. The generations are so long that, by the time the elf reaches the age of having some say around the place, the elf will have been conditioned to obey and not think for himself or herself for millennia. (There was a comparable situation in the US Navy in roughly the 1880s - promotion by seniority meant that there were 40-year-old midshipmen.) [Answer] In Anne Rice's vampire novels, she explores this in some depth. With extended lives comes wisdom and wealth (thanks to compounding interest!), but also a world-weariness and ultimately depression. Lestat finds reason to live by experiencing passionate emotions and immersing himself in them. He does so without regard to any "right" and "wrong" because he's seen the futility of those labels, too. ]

[Question] [ Suppose I take a troop of gorillas and modify them to have human-level intelligence. How effective would they be in a war when compared to modern human soldiers, when comparably equipped? Aside from their intelligence, these gorillas have the same body structure and dietary needs that regular gorillas have, but with slightly larger heads to hold their enhanced brains. Their equipment is similar to human equipment, but modified to fit their bodies. Triggers on guns and buttons on consoles are enlarged to work with gorilla-sized fingers, and reinforced foot-gloves and knuckle guards can take the place of combat boots in helping them get around dangerous environments without cutting up their hands and feet. These gorillas will be serving as combat troops, not piloting fighter jets and tanks, and they don't have any equipment that couldn't be produced with modern technology. They'll be fighting on modern, urban battlefields, similar to Stalingrad or Mogadishu, and their opponents will be human soldiers with the arms and equipment of modern armies. The gorillas are intelligent enough to make their own choices and have chosen, voluntarily, to join the army, knowing full well what that entails. They have received similar training to modern American infantrymen, prior to engaging in combat. How will the gorillas fare? [Answer] They would make ***great*** infantry, and would pose a serious threat on the battlefield. **Stronger** Gorillas are stronger than a human being, and capable of carrying far more equipment/armor. Each of them could easily carry an LMG + ammo, while a regular human soldier would only have an assault rifle and far less ammunition. Having to reload less often, and being able to sustain fire for longer would definitely give them a tactical advantage. Last but not least, if they engage a human in hand to hand combat the human will, unless very lucky, lose. In an *arms ripped off* kind of way. **Lower Profile & Increased Stability** Gorillas are shorter than us, and that actually gives them a fair advantage in an urban setting. A low profile is a thing to be desired when you've got snipers and the such lurking in the shadows. This also ties in with the fact that Gorillas are ***designed*** to operate in mountainous regions. They will excel at climbing over rubble, making their way through ruined buildings, etc. **Conclusion** These Gorillas will move faster than human infantry, carry more firepower, more ammo, and more armor. I pity the poor bastards going up against them. --- **Edit. Or *Why Gorillas as a Replacement for Humans* Is Silly** I'd like to address some of the points which other people are raising, and which, while relevant, I do not believe are deal breakers: **Endurance** A human may very well have more endurance than a gorilla - I actually have no idea. However, why would gorilla infantry be used in exactly the same way as human infantry? Everyone seems to be thinking of gorillas as *replacing* humans, which to me, is silly: there's lots of military gear that would be too expensive to modify for their use. Instead, a trained gorilla soldier would make a perfectly ***complement*** to a human unit. Gorilla units would be used as heavy, shock infantry, right alongside conventional human units. They could be used as support troops, capable of emplacing heavy machine-guns, or carrying mortars and heavy loads of ammo close to enemy lines, or even *behind* enemy lines. How much endurance they have is irrelevant! They can last long enough to do terrible damage to the enemy, at which point you pull them back for R&R, and allow the more rested human troops to push forward. **Caloric Intake** In this day and age we are capable of condensing a thousand or more calories in something the size of a granola bar. Are you trying to tell me that feeding the gorillas, while expensive, would be a deal breaker? Really? No. **Aiming & Weapon Handling** Frankly, I don't see what the issue is. Humans run from cover to cover and shoot from behind said cover. Gorillas would be perfectly capable of doing the same. As far as having to unsling their weapons while they run, I don't see a problem: gear already exists which allows troops to do so in seconds, not to mention that special weapons (wrist mounted solutions, etc.) could be developed for them so they are not defenceless when their weapons are slung. **Edit Conclusion** Gorillas don't have to behave - or be deployed - in the same way that regular human soldiers are. They may not be able to fill the exact same roles, or perform in the exact same way. Like any weapon, they have their strengths and weaknesses, and that's fine. The trick is to use them in such a way that you gain an advantage over the enemy, and I believe that their value as shock troops / heavy infantry is simply *over 9000*. [Answer] If we catalog their relative strengths and weaknesses, Gorillas would be great at hand-to-hand action, but as overall *soldiers*, you'd probably be better off with humans. Strengths: * Strength - They can carry more equipment. Would win most any hand-to-hand combat with a human. * Durability - An adult male gorilla weighs about twice what an adult male human weighs, and their bones are thicker too. So they can take much more punishment than a human could. Wash: * Speed - Both can run in the neighborhood of 25MPH. * Swimming - Humans can swim. Gorillas can't. However, neither can swim very well with a hundred pounds of gear. Drawbacks: * Endurance - Humans are adapted to chasing down bleeding prey over miles and days if need be. * Sleep - Gorillas need about 13 hours of sleep a day, which is about twice as much as humans need. So as infantry, a human unit could march far further in a day, and could remain in action far longer once they got there. If I were the Gorilla commander, I'd try to mitigate this by mechanizing my infantry, and rotating troops (which would require more troops for the same effect as the human commander). There's some terrain that mechanization won't work in very well though, and more troops needed per engagement is another way of saying "less effective soldiers". [Answer] They would be good beasts of burden or soldiers in the trees but not so great otherwise. Gorillas are slow runners on two legs, almost all of their speed comes when running on all fours. They are balanced and build for running on all fours the added weight of a pack would lean them further over. So they have a paradox either run fast on all fours and not be able to shoot or move slowly and clumsily on two legs with a large pack and have their hands free for combat. They are stronger and shorter but in most all combat satiations you need to be able to move fast and shoot at the same time. In forests this could be reversed because humans need to use their hands to climb and hold branches where many apes can hold branches with their feet. In the forest they would be more maneuverable. [Answer] Short answer - no, aside from few specialized tasks. Being a musclebound person isn't enough for be an efficient soldier. ## Stamina Gorilla has muscles. For a living creature, muscles don't go for free, they need a lot of energy from the organism's systems. Considering a bigger brain, the energy consumption problem become even worse. In the wild nature a gorilla sleeps half of the day, foraging for food the other half. Endurance won't be their strong suit. ## Range combat Gorillas might be good in melee combat, but modern combat is about shooting. And shooting is a complicated thing. Gorillas have worse sight than humans. More importantly, their hands aren't designed for precise soft movements, they won't hit any mid-range target. Human snipers will annihilate them. ## Mines and barricades Gorillas won't be good engineers. Even using a barbed wire cutter wouldn't be easy for them, mainly because of how limbs/hands are designed. They can't disarm booby traps, can't handle explosives well enough. Still, despite of a good brain, engineering is weakness. ## Transmitting orders Gorilla's mouth doesn't suit for complex sounds. Basically, gorillas can't talk. That mean they can't use radio, can't report effectively, can't give or transmit orders. They still can use sign language though. In other words, a gorilla (as well as any other animal) is **too specialized** to be as efficient as human in such a complex area. It can be a good hunter, but it can't be a good soldier. [Answer] They might make excellent soldiers for close quarters combat in tight urban environments, where engagement is expected to be almost exclusively melee. Unfortunately, this severely restricts their usefulness. I'm reminded of storm troops in trench warfare of the first world war - fast brutal engagements where rifles are of little use as combat is more throwing grenades then jumping into tight spaces for brutal hand to hand fighting with clubs, knives, and sharpened shovels. In those kinds of situations, gorilla shock troops would be devastating. Their ability to carry heavier weights might give an advantage for transporting heavy weapons through difficult terrain - carrying machine guns or mortar tubes, with lots of ammo, might prove useful. Unfortunately for the gorilla, modern warfare is mostly skirmishers. The ability to quickly run around while engaging with firearms is of primary importance, and gorillas would be inferior for most modern purposes. [Answer] They would make fearsome opponents in close combat but a lousy at even reasonable range for a human shooter. A good commander with human troops could probably counter them by playing to their weaknesses. Consider the reason for their strength. Their ligament attachment is optimized for strength, but at the cost of fine motor control. They'd be laughably bad snipers, but you wouldn't want to face one in melee combat. Their weapons would be short range (blunderbuss shotgun sort of thing, arm mounted canons) they might recognize this lack and create computer assisted aiming (remember they're as smart as people and so could recognize their weaknesses). Also consider area damage weapons like mortar but less directed. Humans are also tops in the world for endurance running. In history humans excel at running our prey to death. This would also give them a disadvantage for fast, long marches. (imagine a human commander pushing his or her troops hard in retreat, setting up distance attacks along the route and then flanking from high ground) All in all the advantages and disadvantages balance well and could lead to interesting circumstances. Differences in temperament should also be considered. [Answer] No, they wouldn't be more effective. The biggest issue would be the massive amount of food they would need. A quick search quoted a male can eat around 50 to 75lb of food a day. A typical human soldier can be expected to consume 4500 to 5000 calories per day. This is slightly more than double the calories that a civilian would consume, leading me to expect a gorilla soldier would need to carry minimum of about 100lbs of food for each day. Even at base the amount of food needed would make a logistical nightmare that could easily be attacked. Another issue would be endurance. Being much lighter we would likely be able to outlast the gorilla. Obviously you wouldn't want to go hand to hand with them, but that doesn't happen often. Edit - Nutrient paste probably wouldn't save much in the weight. The issue is the fact vegetation is the main food source. A nutrition bar with lots of calories probably requires foods they may not be able to handle. I found an article on zutrition.com listing 8000 calories as the daily requirement for a adult male gorilla. That is three to four times what you would feed a human soldier. The issue here is the only advantage gorillas have is strength. Strength is not a big plus in the modern military. The only thing I might use them for would be to carry equipment for the humans, and I doubt they could actually keep up with the humans. I don't think they could stand upright to shoot for long. Humans can and do move and shoot, especially in close combat situations (Think SWAT teams storming a building, they move forward with the weapon in the firing position). Equipment and training are the important factors in modern combat. If you look at many of the battles that have happened in the last 25 years, highly trained troops were able to attain kill ratios above 10 to 1. The Blackhawk down battle is an excellent example. [Answer] Your gorillas will not perform as well as human soldiers. 1. Their basic instincts are still more prevalent than humans Where we had millenia to overcome some of our basic fears and instincts, it is still a problem that has to be overcome with rigorous training. Granting an animal enhanced intelligence, does not allow it to suddenly overcome its base urges. Once this weakness is observed by your enemy, it will be easily exploited. 2. Their natural hunched positions make them slower to adapt to ranged combat Humans have adopted an upright position, which makes aiming down the sights of a rifle a trivial thing to learn and easier to master. On the other hand, the hunched position of the gorillas means that they will be less comfortable, by nature, in assuming a firing position. Which means that they will likely adapt slower to ranged combat. 3. Their physical needs make them far more reliant on a large supply chain. Battles are fought on a battlefield by soldiers commanded by superior officers. Wars are fought over tables by logistic officers. The fact that your troops can carry more means little in an actual combat situation. And while they can haul supplies while moving towards their position, they can't hold their posts packed like mules. You'll need to foresee for their massive dietary needs. 4. You don't win a war with one special unit, you win wars with numbers. While you are sinking costs into R&D for monkey suits, your enemy has outfitted 10x their number in human troops. It's not worth it just to have a storm-trooper that hits harder with a club. 5. Their active window is only a few hours a day. Taking into account their 13-14 hours of sleep a day, 1-2hours spent consuming massive quantities of food, and another hour for moving between locations, you have troops that are active 9-7hours a day. This means if you want an around the clock troop presence, you'll need about twice as many troops as your human counterpart. 6. The age of hand to hand has ended. Your gorillas won't be any less susceptible to an expanding casing burrowing through their skull. Likewise a land-mine will take out human or ape alike. If you plan on clearing out a building, specialized troops with equipment meant for close quarters combat will do a far better job. I don't really think when clearing out an entrenched position, it matters if the hand that holds the shotgun is hairy or not. As long as you have more of them and are better supplied than your enemy. By the time the fists come out, it's more likely in a drunken stupor during the aftermath of the conflict. [Answer] I'm going to add this as an answer instead of commenting as it touches on different topics, particularly the fact that modern infantry isn't fighting in a lot of wide open areas like in the past. An urban environment is what was mentioned and doesn't seem to have been focused on enough. 1. Experience - you describe a scenario where you take already grown gorillas and hand wave them into being intelligent. That's all well and good if you want to educate them to show off at an academic conference, but that is a horrible idea for a soldier. What you are really doing is creating the equivalent of physically superior child soldiers because they have almost zero life experience to draw upon as soldiers. They won't know even the basics about human life and our habitats and teaching this combined with everything else that they need to know to be effective soldiers in an urban environment would take years. Otherwise they'll simply be brawny thugs shooting anything that resembles what you have qualified as a 'bad guy' and most likely being tactically outmaneuver very quickly. 2. Cost - Human soldiers have been the focus for our infantry for thousands of years. Unless you're planning to have had these intelligent gorillas around for a long time, then nothing will have been developed over time to suit them, it will have been adapted for them, and that is a problem. You even mention creating a new kind of 'foot' wear just for these new troops, along with modifications to other equipment. That is simply the beginning, as others pointed out, because they have not evolved for acting as humans do. If this organization decides to suddenly attempt this gorilla soldier idea, then it is going to cost them a ton to get what is likely very little return out of it. Basically, gorillas are better for the exact opposite of what you're wanting them to do, which is fight in tight, modern, urban environments for a simple reason, they're animals and don't live or operate in these areas naturally. If you wanted melee soldiers for an older style of fighting in mountainous terrain, then they'd be great, but for this I would say no. [Answer] Close quarter assault with specific tactics is the only saving grace I can see. And being disposable (you have some industrial breeding farm, don't you?) As many mentioned before me, they have limited endurance, diet is a serious logistic problem and street/forest warfare is a lot about short burst of speed which is less efficient when you have a large body mass. If humans can afford to retreat, they'll move faster and can lay ambush anytime. Even more important: human-level intelligence is not human-like intelligence. Dolphins probably have human-level intelligence, but we simply can not communicate. Being able to carry much weight allow to carry bigger guns. So there is that. But I think their real strength would be hand-to hand combat. Let's be clear: modern military stressing the importance of hand to hand combat is 84.6% testosterone fueled bravado. But with a brigade of gorillas, you can make dedicated tactics. - Put a MASSIVE bullet proof vest. They can carry it - Bring them close to the target (standard street warfare ) - Go berserk on the last yards. They would be especially good at this in the forest (rush through bushes is not natural for humans) - Kill the target with bare hands (break the neck, step on them...) or bayonet. I would call this a suicide attack (they kill the target only to die from their wounds) but hey! those are only gorillas... [Answer] You might consider using uplifted chimpanzees instead. They aren't quite as strong as gorillas, but they are still much stronger than humans without many of the disadvantages people have mentioned for gorillas. * **Logistics:** because they are more similar in size and physiology to humans, it's easier to reuse/adapt equipment, vehicles, weapons, & medical resources * **Weapons Training:** non-uplifted chimpanzees can already use projectiles as weapons * **Instincts:** more aggressive in nature and engage in inter-group "warfare" in the wild * **Mobility:** better adapted for climbing, covering longer distances (compared to gorillas, not humans), and less sleep/rest References: 1. [Osvath, Mathias (2009-03-10). "Spontaneous planning for future stone throwing by a male chimpanzee". Curr. Biol. 19 (5)](http://www.cell.com/current-biology/abstract/S0960-9822(09)00547-8?_returnURL=http%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982209005478%3Fshowall%3Dtrue) 2. [Wilson et al., Lethal aggression in Pan is better explained by adaptive strategies than human impacts. Nature, 2014; 513 (7518): 414 DOI: 10.1038/nature13727](https://www.sciencedaily.com/releases/2014/09/140917131816.htm) [Answer] As other answers have pointed out, the cost and time spent designing and building armor as well as weapons for your gorilla army would cost more than they would benefit you. The only time that this would be effective was during the pre-gunpowder era, when body strength was the single highest factor in warfare. during this time, even giving your Gorilla's a club and a plywood shield would be as effective as a regular infantryman, simply bum rush. But from what I can tell, this question concerns modern day warfare and in modern warfare, gorilla's are more expensive to employ than they are worth. ]

[Question] [ Instead of discovering that earth was round, we find that we live on a infinite, flat "earth". What are some cultural implications if we were to live in a world like that (disregarding any physical impossibilities, and that gravity, biological/ecological systems remain roughly the same as reality). One interesting idea is that cities could be tens of thousands of kilometers from another and that one can only explore so much of the world in their lifetime. EDIT: I don't mean flat as in geometrically flat, but flat in general. There would still be mountain ranges and oceans and forests and stuff. But there would be different and exotic ecological systems as you travel. [Answer] The world would become progressively more alien as you moved across it. Unlike on Earth, where animals and humans can move across the entirety of the world given a few thousand/million/tens of millions of years, an infinite flat earth would always have somewhere that's far enough away that nothing from where you are has ever been there. This would probably lead to a continuous cycle of mass extinctions brought about by animals migrating in from a place where they have evolved in a manner that allows them to out-compete their neighbors. Something like Europe could exist, with mammals and birds forming most of the terrestrial fauna, when a group of highly evolved velociraptors finishes ten million years of gradual migration and then decimates the entire local ecosystem. At a great enough distance, *nothing* would have even a single common ancestor. You'd likely get great patches of land in which only single celled or incredibly basic forms of life exist, since this form of life evolves in abiotic conditions relatively quickly, but then takes billions of years to become multi-cellular. These stretches would separate islands of complex life, which would become increasingly complex and highly evolved at their centers. Aside from the mass extinctions that would occur when these life-islands grew into each other, different life islands could also evolve their own sentient species. These species, again, wouldn't share any common ancestors, and could well be separated by hundreds of millions of miles. They would all be incredibly alien to one another, more different than humans are from plants or mushrooms, but they could eventually come into contact with one another. Physically reaching one another would take quite a bit of time, since they'd likely be separated by immense distances, which would be difficult to traverse, but across which radio waves could probably travel. [Answer] This would actually be really awesome. It wouldn't really be a planet anymore, but it could conveniently be called a plane or plane-et. **We could find the epicenter of life.** Presumably, abiogenesis is quite rare. On an infinite flat Earth it will certainly have occurred elsewhere, but not likely very near to us. Theoretically, we would eventually be able to travel fast enough that we could get to the edge of life. This is similar to how we look at the background radiation of the universe to see its birth. **Aliens on the same plane-et** Because life will have certainly occurred elsewhere (a vanishingly small chance in infinite space is a guarantee) we could meet lifeforms that would be totally alien to us, but clearly able to live in similar conditions. They might even be significantly more advanced than us. **Geo-location would be difficult** We couldn't build geosynchronous satellites. No GPS. For something to remain geostationary it would need to constantly thrust. Orbit wouldn't be possible. Getting the satellites into the same impossible space as the Sun (or moon if we've got it) wouldn't help because they wouldn't be good references for geolocation. The best we could do is built beacon towers. But the range would be incredibly limited and line-of-sight requirements would make it fairly ineffective. **Infinite resources** Obviously we wouldn't need to worry about resources so much. Including fresh air and water. We could pollute as much as we wanted because there would always be more resources further away. **Nomadic Lives** Most likely we'd live a long term nomadic life. Is it really worth building a massive city when the resources in the area will eventually be used up? Why would a farmer preserve their land if it's so much easier just to keep moving? When something like land becomes infinite, it's hardly precious anymore. We'd use it up and move on. Maybe we'll circle around in 10,000 years when things have replenished a bit. [Answer] A lot of people ignored the question and delved into the rabbit hole of physical impossibilities given the physics of our known universe that were ruled out in the question. Given an infinite, planar type world with similar characteristics and physics to earth (though I am not sure how different temperate zones would come about) I agree that with others that life would develop separately in different locations. With infinity there is the possibility that completely separate forms of life (e.g., non-DNA based) would come into existence. I think the question is also interesting starting with a planar non-infinite landscape. But in general, I think life forms would spread gradually over the landscape as they do on earth (though probably from different pockets of life on the infinite landscape). I do not see why, as one suggested, that we would continually (as a whole) be nomadic just because the world was infinitely flat. The answerer's premise was that we would run out of resources in one area and because of the infiniteness of the world, land and resources would not be valued and we would pull up stakes and move on. But just as happens here on earth (according to the premise), the land would replenish itself, and I think people would spread out naturally as population/resource pressures arose. The whole population would not pick up and move as nomads. And unless there was a scientific way to determine it, I do not think the population would realize the world was infinite so population migration would probably proceed much like it did no earth. They probably just wouldn't do the type of exploration we did to find shorter routes to places based on the curvature of the world. [Answer] Life starting from a single point will create a so called [Fairy Ring](http://en.wikipedia.org/wiki/Fairy_ring). Life will move outwards, expanding the ring seeking for a new resources. Many concentric ever expanding rings may be created as a new life evolves, that is able to use resources that the life in the previous ring was not able to use. [Answer] There's a lot of assumption that must be made here for this to work...I'm not entirely sure if life would ever evolve past single celled organisms as space scarcity is non-existent...it'd just expand forever in every direction as a one celled organism. It's possible that mammalian life would never come to dominate the planet as there isn't much room for mass extinction events either. If Humans did come to be, it would stand to reason there would still be dino's running around on the far frontiers...they did get several hundred million years to expand in every direction possible after all. I highly doubt a working plate tectonic system could exist, which makes the land much more flat and I don't think you'd get much for mountains or deep oceans. I'd have no clue how geological processes would work in something like this either...infinite space = no pressure = no volcanoes? I'm not even sure you'd see hills. No clue how suns and seasons would work...if at all. On a flat infinite planet, the suns rays would go off in all directions and you could probably see the next sun coming along way way off on the horizon (would there even be a horizon?). I doubt you could get a day/night cycle that even came close to resembling earth. I'd suspect you'd get a series of lakes before you'd get oceans...tides wouldn't exist either. Climate would be...well if air currents are influenced by the spin of the globe and a flat land has no spin, I'm really not sure if there would ever be dominant wind patterns. Rain is also affected here...if there were no strong trade winds to relocate rain to land, is farming even feasible? While I'm at it...it took millions upon millions of years for earths atmosphere to take the composition it has today...if there was a strong wind from one direction or the other, what happens when the air it draws is from a region that plant life hasn't made it to yet...would the air even been usable to us or animal life? A near infinitely large forest fire could create a cloud of smoke large enough to extinguish life as it floats over the infinite land. Thermohaline circulation depends on a round globe (Thermohaline circulation is the 'great oceanic heat conveyor belt')...so heat distribution wouldn't be earth like. In Earths case, this would result in the northern atlantic, most notably England, Scotland, and Ireland to be completely frozen over. You'd most likely have extended glacial regions that reach from the area's that receive 0 sunlight and a middle band where the sun (suns?) travel on that are much warmer. Edit point - a flat land would be struck by sunlight evenly across it's entirety no? There might not be an arctic. Would the planet have a magnetic field? Of course it couldn't exist naturally (just like the gravity situation) and would need to be handwaved into place...are there multiple magnetic norths? Is magnetism ever a possible method of navigation? I guess the stars wouldn't really move in this setup, so I would guess that stars would work for navigation quite well. Err..or maybe...you couldn't really have a moon as it'd eventually impact somewhere across the infinite. The stars really couldn't exist as they'd eventually come crashing down as well, no? With no magnetism and no starscape, navigation would be exceedingly difficult. Is there a north/south pole, or is it infinite in these directions as well? I guess you'd need multiple suns to be over the planet at all times...actually you'd need an infinite number of suns over this infinite land wouldn't you? Now to the cultural implications of a world of infinite size...I hate to say it, but you're in the range of 95 - 99% of this infinite plane existing in the realms of magic or if you'd prefer a 'god' crafting it...that same magic can be used to justify whatever cultural implications you feel like. [Answer] With infinite living space, population control might not be such a major concern. Isaac Asimov's essay "The Relativity of Wrong" can also be a good reference as to why the Earth was/could still be seen as flat... But what if the concave curvature of your living surface was that of the Earth's *orbit* instead? Idea is from a Larry Niven sci-fi novel "Ringworld". An oversimplified immersive approach to visualizing said infinitely flat(relatively!) land would be found in a game of Halo. [Answer] While abiogenesis might have a singular origin (with descendants of that singular event outracing any "new" events) as some of the answers have described, various other "steps" [multicellular life, intelligent life, industrial civilization] may not be so rare, and you could have multiple societies of different species and even entirely different anatomical basis within the same "life island" with the same basic chemistry and backdrop of oxygen-producing single-celled life. You wouldn't have to go so far as the "edge of life" to find "aliens". The edge of hominids, or of land vertebrates, would suffice. The further out, the more alien. The first "aliens" would probably be human, or very nearly so (almost certainly a species descended from the same *Homo/Australopithecus* line.), which had independently developed to the point of inventing rapid transportation and radio. On the subject of rapid transportation, in the book "Missile Gap" (in which Earth's continents are transplanted to the surface of a very large but finite flat megastructure), a large [Ground-effect vehicle](http://en.wikipedia.org/wiki/Ground_effect_vehicle) was used for exploration. (The *name* of the book, incidentally, comes from the fact that intercontinental ballistic missiles are not a viable technology in the uniform gravity field caused by such a world.) [Answer] I was actually at a planetarium this weekend and I thought of this question based on a display that was there. It had the travel times to pluto and Proxima Centauri based on a car, a plane, and a rocket ship and then light. What that drove home to me was that I think most of these answers are looking at things from too high of an abstraction perhaps. On earth if I get on a plane there is a limit to how far I can travel; on this flat world there isn't, not in any direction. There isn't going to be just the Panama Canal and the Suez Canal but probably some Northwest Canal and a Hyperion Canal and a Southern Canal and that is still just in the same grid as we are in; There will be many, many more before one gets to the distance of the moon (1.3 light seconds away); which going a constant 80 mph 24 hours a day would take one 124 day to reach (or 248 to travel from one end to the other). In this setting what would a MAD policy even mean? one could just out fit a fleet of Zeppelins and travel, but then again there is no assurance that one would necessarily reach a place one could live/conquer even if one traveled ones entire life (or many lifetimes). Likewise, the notion of a "UN"; there would always be nations known to at least some of the member nations that are not part of the UN, and eventually it would reach the point where traveling to and from meetings would take longer than meetings themselves would, or even longer than ones life; while still being much shorter than what can be communicated. The speed of light being so much faster than anything else, it would be trivial to be able to communicate with people with whom contact is impossible. Mars is 3 light minutes away at closest approach but traveling at Mach 1 would take about 22 years to reach that distance, so quite close enough to communicate with via radio (or on stackexchange using fiber optics or satellites fixed to the celestial spheres, even if first person shooters might be out of the question) but generalized trade wouldn't really happen, not via shipping or rail or plane or even supersonic flight. So there would be a limit to everything as we are finite even as the world would not be; nations may be fine with nuking some cities and conquering areas many times larger than our earth but eventually either in war or in peace stability would be reached as in 1984 in regions where to go further from their central regions is not worth the marginal effort of doing so. There would also be many more opportunities for Columbian exchanges to happen, where technologies, foods, and illness (which can be devastating) from one area mix with another (giving the Old World the potato, tomato, chili pepper, corn, chocolate, etc.) Which means that even long trading expeditions could end up being very profitable. Sure the fragmentation would mean that eventually the people that one is trading/communicating with may not even be people any more (I mean we already dealt with/are still dealing with that idea in our own pale blue dot) but they are really not any stranger or more dangerous than the people who closer at hand but still far enough away to be different than one is oneself, which as already pointed out can be literally next door. [Answer] Any world where an immortal can travel forever without repeating themselves has some interesting implications, some of the things to think about include the migration of disease strains through various populations, plant, human and animal, that call this world home. What happens when nomadic tribes that haven't stop moving in generations run into areas of closely settled farming communities where no-one goes anywhere and haven't for generations either. The migration of new plants and animals across the territories of the universe, introduced pests, the existence and extent of natural barriers like oceans and mountains is important as well. In fact in this kind of universe the water/land balance becomes of vital importance to how things move, if all bodies of water are ultimately landlocked then they don't provide a barrier to migration only a detour, if on the other hand all continents are ultimately islands then migrations are heavily curtailed in the overall scheme. Oceans may be too large to navigate, rivers too vast to bridge, deserts too wide to cross, any geographic feature that can act as a barrier or even a resource can potentially be so large as to create problems for mortals. A wood cutting camp may disappear into the forest they're cutting as regrowth cuts them off from their compatriots who still get logs floated down stream to them but have forgotten from whom they come. Human memory itself becomes a problem in dealing with such large distances. How far and how fast waves of civilisation grow and collapse across an infinite space is also important; start with the speed of communication and transmission of force, whether aimed at revolting peasants or securing a border, this really sets some limits on centrally organised cultures. A traveler from a civilised enclave will probably be out of touch with their birth culture rather rapidly and into truly alien cultures reasonably shortly thereafter. In theory you could have a culture that spreads at the same rate it fails creating a ring of cities and industry that expands across the world leaving a growing circle of ruins in it's centre. Also consider what limits there may be on technological growth imposed by resource availability, if the world is flat is it also thin and therefore relatively devoid of mining opportunities The other thing to look at is kind of the opposite of all of the above it's about things that are similar not things that are different. Ultimately in a truly infinite space you will leave behind your cultural, and possibly even your genetic, heritage but it's important when working on a world so vast to think about how far certain practices an individual takes for granted *are* distributed, can an immortal find that though they've walked 50 miles a day for millennia they still find that everyone they meet grows wheat and bakes bread or can a man walk but three days up the road and find the world is unrecognisable? How far can you go and *not* notice the differences in how the world is "out here". That's just a few thoughts from a piece I've been working on, on and off, for a while, that uses Cosmic Macaroni as the backdrop but the principles are the same. I'm going to have to think about uses for an infinite flat space I've done "humanly infinite" spaces and objects before (worlds so large that nothing living in them lives long enough to see any noticeable fraction of them) but never flat spaces. [Answer] Most of the answers until now have focused on biology/evolution, even though you asked about cultural implications. One of them would be that all reference points would be, of necessity, local. Each place on the infinite Earth-plane could and would probably be considered as the center of the universe (figuratively and/or literally) by its inhabitants. You haven't specified how this flat Earth would be lit, but a single sun (or light source of any kind) could never be enough, so there must be either some kind of luminous sky or multiple suns revolving "up there", for example. In any case there would be no north, south, east or west. Navigation would have to be done using notable local landmarks such as mountain peaks. In a flat plane the "horizon" would not exist; things would just appear to become infinitesimally small in the distance, in a clear day, or obscured by air itself (no mixture of gases is perfectly transparent), so people who happened to live in a place with no great mountains around would effectively lack all navigational clues. Religion and science would include these things in their paradigms. They would have to cope with infinity. Some could imagine that reality must be finite and therefore everything outside a given radius from the local origin is an illusion. Legends could be common about some adventurer or prophet who travelled to the end of the real world and came back. [Answer] One important factor of this world is that it is concave. Or at least it looks like it. When light bounces off of an object, it will be subject to gravity, like all other things. If this gravity is uniform, the light will eventually, even after a massive time, fall back to earth. As there is only a finite height of air, this light should be able to go through the atmosphere and be seen. This would mean that there would be a slight curving effect. I'm not sure how to calculate exactly how the light would move and form the image, but the world could resemble something like a reversed stereographic projection [Answer] Not good (or at least, not much better than our history). The issue is not only as much "real estate" you have, but how much of it is usable. For example, most of the Earth surface has no human population (the oceans, Antartica) or just a bare minimum (deserts, Amazonian). In that sense, if your area becomes overcrowded, maybe the nearest free soil is too far away (or has to pass through too many of other tribes'territory) to be of any actual interest. So you would begin with isolated human groups, which would grown and expand. At the beginning, most of them would be able to send excess population out of the frontier, but with time the "frontier" tribes will find that the free soil is too far away (think how once, the USA frontier run through the Appalachian Mountains). As technology progresses, the "frontier tribes" would become bigger and bigger (because with better technology is easier to keep the political unity). There would be cycles of frontier nations becoming too big, desintegrating in several nations, and the new "inner" nations using their power to push back the weaker nations of the privous cycle. Probably, sometimes population pressure in the older (inner) nations would lead to massive migrations/waves of conquests, like those of the Germanic peoples or the Mongols. ]

[Question] [ The unicorns would be used to charge a line of infantry with their horn. They are as big as a horse and the horn is similar to this image:  The infantry is a standard medieval army made mostly of soldiers wearing longsword, wooden shield and chainmail. If I use my unicorns to charge the enemy’s infantry, are they more likely to die in the attempt or will they cause massive damage? [Answer] That depends on a tactic. If you just have two swarms of different meatbags charging at each other, then the one with more speed and durability wins. You didn't provide any numbers, but assuming 1-1 ratio, even normal horses should be able to defeat the humans, longswords or not. Horses are big, powerful beasts: <https://www.youtube.com/watch?v=-srzT2olJ2Q> <https://www.youtube.com/watch?v=J95LsygVMaQ> They can kick, bite, or just run you over. And when it's charging, and you stab it with your tiny long sword it'll have enough momentum to run you over, most likely killing you and the guy behind you. And now let's add a horn to that scenario. With them, you may never even have a chance to use that sword - you'll be a dead long before the beast is in range. Now, there are ways to defeat them, even with such weak weapons like swords. One of them is preparing the battlefield to your advantage (for example by digging trenches). Given the title I assume that we are talking about an open field, so we can cross out this option. Second tactic would be scaring the beasts off with noises they don't like, fire, commotion, etc. I don't know if it's possible in your setting. Third way I can think about is simply outnumbering them in overwhelming odds - but expect HEAVY losses, because it will take lives of several men to kill one horse (and even more with a unicorn). But if your question was about only about the first impact in an open field, then my answer is that there will be no line of infantry after the two forces meet. [EDIT] To address a good point made by @Monica Cellio in a comment: I'd say that killing a horse (or a unicorn) with a long sword is a no small task. For starters, let's assume, that we have one man trying to kill a unicorn, which cannot fight back. The only restriction is that he has too attack beast's front. What are his options? He can try to attack the head. Good luck with that. Here is how a typical horse looks from the inside: <http://www.infovisual.info/02/072_en.html> You'll notice, that it's pretty much nothing but a skull. You may have some luck with a hammer or a [pick](http://en.wikipedia.org/wiki/Horseman%27s_pick "Pick"), but a long sword is most likely the worst weapon to use for such attack - it will scratch the skin and bounce off the bone. A horn provides even more protection. Next on the line is the chest. In this case it is a matter of luck, but even if you somehow manage to stab right through the heart, it will take a couple of seconds before the brain runs out of oxygen, so even with best of luck, you have no chance of an instant kill. But that is not a likely scenario. In most cases the horse would look like this:  Please notice, that there is not much of the chest visible to hit, mostly it's protected by the head. If you get the chance to stab the beast, you'll most likely hit hard and dense muscle tissue - not exactly an armour, but you need some effort to go through it to juicy internal organs. I'd say that your best chest option is slash it several times and wait till it bleeds out. Last but not least - legs. Hard bones, surrounded by muscles designed to move a heavy body with a great speed. This, however, is your best option - you won't kill the beast, but if you damage the muscles enough, you'll incapacitate it for good. Long sword is best used for slashing, and that's exactly the kind of damage you need for this task. And now apply the story scenario: the unicorns are charging, the attack, fight back, there is a lot of kicking, screaming, nobody really knows what's going on. Complete, utter chaos. Some soldiers will get lucky and damage the legs, some unicorns may bleed out afterwards, but I don't think that swords will be much of a use in this case. Not enough time to use them properly, not enough space and the targets fight back to well. So to rephrase the original question: **Charging unicorns WOULD survive an impact with a line of infantry.** [Answer] As the "real" unicorn horns (in our world) were scavenged from Narwhals, I guess we can just take this as base: > > A unicorn is a huge, strong horse with magical powers and the tusk of a Narwhal > > > Else we couldn't do any kind of reality check on that. ## Tusk / [Alicorn](http://en.wikipedia.org/wiki/Unicorn_horn) The [tusk](http://en.wikipedia.org/wiki/Tusk) itself is 1,50 - 3,10m (60 - 120 inches) long [Source: Wikipedia](http://en.wikipedia.org/wiki/Narwhal). As elephants and rhinos have tusks as well, we can assume that it's pretty durable as it's used in battle and during charges on rivals. You can read in the book *[Mammoths, Mastodonts, and Elephants: Biology, Behavior and the Fossil Record](http://books.google.at/books?id=PRrZ-TK91LMC&pg=PA41&lpg=PA41&dq=density+tusk+elephant&source=bl&ots=NrLWjCIZ7o&sig=0M5SHSRxpe57Eu6eOjpsg15Etoo&hl=de&sa=X&ei=hS16VKD7D47masrOgvgN&ved=0CDEQ6AEwAg#v=onepage&q=density%20tusk%20elephant&f=false)* by *Gary Haynes*, that the densest tusks (or "dentinal tubules") are those of Mammoths and Mastodonts - both old species. What makes them interesting for us is that they had tusks which *"[...] grow spirally in tight curves[...]"* like the ones of Narwhals. Due to their high density they could grow larger and were much more elastic. Something that might be important for a horse that has a minimum 1,50m long horn sitting on his fore head. Different sources have a wide range of densities for tusks. They go from 3,00 g/cm³ up to 5,00 g/cm³ for Mammoth. I think we can safely assume that a Unicorns would range at the upper end of that scale. ## Alicorn/tusk density Default horn/tusk/keratin has a pressure resistance of 30 kN/cm² (which is 3 tons per square centimeter). The horn of an Unicorn is assumed to have 25cm² (5x5cm; guess based of images of Viking spears forged out of Narwhal tusks) and a much higher density. The lowest quality horns have an elasticity of 3% (3cm moment per meter). That means that a *stiff* tusk of low density would with that surface at least withstand 750 tons pressure before it starts bending. ## Horse height As base, taking the length and weight of the tusk into account, I'd go for an unusually large horse. The largest breeds are [Shire horses](http://en.wikipedia.org/wiki/Shire_horse) with a height of 1,70+ meters or 68 inches. I'd assume it to have a shoulder height of at least 2,00m or 80-85 inches. ## Horse weight When you look at breeds with a good duration and good jumping and racing abilities like the [Akhal-Teke](http://horse-breeds.findthebest.com/l/37/Akhal-Teke) Source: horse-breeds.findthebest.com (or similar), then they have a weight between 800 up to 1.1k pounds (360-500kg) at a height of 15 to 16 hands (60-65 inches/1,50-1,70m). When interpolated up to a unicorn, this would be around +25%, so we end up at ~450-625kg (or ~1k-1350 pounds). ## Horse speed Top running horses (you will have to look up different sources for confirmation) can go around 55mph (85 km/h): "Quarter horses, bred and raced for short distances at speed". I'd assume a magical horse-like species who is larger to go even faster than that and take their charging speed (or the impact speed) up to 100 km/h (60mph). ## Calculation All above tears down to the following data ``` impactor density: 5 g/m³ human body av. density: 1,05 g/m² impactor diameter: 0,0001 m² (5cm x 5cm impactor size) velocity: 27,78 m/s (100 km/h) distance from impact: 100 m impact angle: 90° ``` The needed formula is pretty much the same that we would need to calculate the impact force during [a car crash](http://hyperphysics.phy-astr.gsu.edu/hbase/carcr.html): $$\frac{-\frac12 m v²}{d}$$ For the sake of a shorter answer, I'm not doing the math now, but the resistance the unicorns horn would have would be equal to sticking a spoon into a glass of jar. The unicorns weight at this speed hitting a human body with such a small surface would be more than just a few tons and worse than getting knocked over by an average sized car at the same speed - impactor surface matters. In other words: The soldier would be torn apart. ## The attack / Conclusion Depending on formation (I would imagine it to be triangular), the soldiers would not stand a single chance. A long sword (and even a rapier) are shorter than the shortest horn. The density of the horn wouldn't be a problem (for the unicorn) and just knock the chains apart (which already has been a problem to this kind of armor when crossbows were invented). # TL;DR > > 1:0 for unicorns > > > ### Notes I switch between Metric and English units. The English separator [used in this answer] is a `.`, while the Metric is a `,`. I tried to avoid the thousands separator whenever possible. Still, 1.1k pounds equals 1100 pounds. The height of a horse is measured in [hands](http://en.wikipedia.org/wiki/Hand_(unit)), which you might want to refer to in your story. I think it adds a nice touch. A *hand* equals 10 cm or 4 inches. [Answer] Depends on your unicorn. An [Elasmotherium](http://en.wikipedia.org/wiki/Elasmotherium) was twice the height of a human and weighed 4 tons (other sources say 6 tons). It (probably) had a 2m armoured horn with substantial muscle to control it. Probably a vegetarian but likely fierce if threatened.  > > Legends and names referring to a special type of unicorn or mysterious beast with one horn, as opposed to the delicate imaginary unicorns of Europe based on narwhal horns, are scattered across the former range of Elasmotherium from China to Eastern Europe. They have been noted there since the first known literature of the Middle Ages. ... > > >  > > In the northeast of the range, in 1866 Vasily Radlov reported a legend among the Yakuts of Siberia of a "huge black bull" killed by spear, who had **"a single horn" so large it required a sledge for transportation**. In 1878 A. F. Brandt suggested the beast was an Elasmotherium.[58] In Yakut mythology is known also the one horned Bull of Winter with pale blue fur. It symbolises winter and frost. In 1921 Gavril Ksenofontov collected some Sakha legends about huge, one horned bulls, usually with pale blue or dun, long, wool-like fur. The big bull with a single, long horn is mentioned also in yakut epics Olonkho. > > >  So if you want your unicorns to win then choose this type of Asian unicorn over the namby-pamby European 'magic horse with a horn' type. Unknown psychological factors aside, it's hard to imagine the humans being victorious armed with any weapons less substantial than a [main battle tank](http://en.wikipedia.org/wiki/Main_battle_tank). This type of unicorn has the advantage of actually having existed and being real. Also you don't need to worry about possible enemy deployment of tactical virgins. [Answer] Longswords? Sure. Many unicorns will fall to the longswords, but there is a reason the cavalry charge was a standard military tactic. It it not fun to try to stop several tons of horse with a mere pointy piece of metal. However, add pikes into the mix and the story is different. Pikes were designed to stop the horses (violently) out of range of the infantry. After that, calvalry charges were used as a flanking attack, attacking unprotected sides rather than front on charges. [Answer] **A lot of unicorns would die in the immediate crash, or by getting stabbed to death on the ground by infantrymen.** I will elaborate on the mechanics after giving a short military history background on the subject of cavalry vs. infantry, which has been more or less completely neglected here. I am puzzled as to why Oldcat's answer was downvoted, but except for Dronz and vsz, he is the only one focusing on the most important part of a battle: psychology. The main objective of a cavalry charge was **not** to ram into a wall of humans, but to intimidate the enemies before contact - making them turn around and flee, which means that the battle line is dissolved and individual soldiers can be cut in the back by the riders. The main objective of an infantry line holding ground against a cavalry charge would be just that: to hold the ground long enough for the charge to be broken up. With horses, especially ridden horses, it is as simple as that - they won't go through something they perceive as a solid wall. But holding ground when hundreds of animals are galloping against you, sounding worse than thunder, and with armed warriors in the saddles, is probably easier said than done. There are very few occasions when a close formation of infantry soldiers held ground and a horse actually galloped right into it. Extremely few, I might add. It did happen once though, during [the battle of Garcia-Hernandez in 1812](https://en.wikipedia.org/wiki/Battle_of_Garc%C3%ADa_Hern%C3%A1ndez): > > On this occasion one of the leading cavalrymen, a Heavy Dragoon of the King's German Legions, was killed close to the French square. Both horse and rider were shot and killed in mid-stride, but momentum and a nervous reaction kept the horse moving, so that it finally toppled over on top of the French infantry, dragging men down with it. This dead horse had done what no living animal and rider could have done, and actually struck the face of the enemy square, creating a gap and allowing the rest of the unit to enter. (Goldsworthy, A. K., 1996, The Roman Army at War, p. 230) > > > The problem with reasoning along the lines that a cavalry unit could use its momentum to break up a solid line of long sword equipped infantry men (it is actually not that relevant what kind of weapon they are carrying, unless it is pikes or long spears which are excellent against cavalry, what matters most is the tightness of the formation), is that the same momentum would be devastating for the horses and riders alike. That would in most cases be true for one horse versus one man on an open field. But different factors weigh in when we are talking about formations. A skewered infantry man does not vanish the second he is killed, nor is the path behind him cleared. A fraction after being speared to death by the unicorn, the unicorn would crash into the man. It could power through until the next man, with a soldier hanging on its spear. But inevitably, it would topple over and drag down several soldiers with it in the fall. A split second later, the next wave of horses would crash into the heap of soldiers and jerking unicorn legs, or they would leap over the heap - only to crash into the following lines of soldiers. Then comes the next way, and the next, until it is all a bloody mass of fractured legs, skewered torsos, long sword-impaled unicorns, and so on and so forth. Clashes of cavalry and infantry lines can be seen in literature and movies, but they did not took place on a regular basis in any war the military historians know of. And for them to take place when unicorns have replaced horses as animals in a cavalry unit - well, it would presume that the unicorns in question all entirely lack self preservation, and that is entirely up to the OP to decide upon. **Summary:** If the unicorn psychology was very different to that of a horse, then it would suffer the same consequences of crashing into a mass of bodies as a horse would - resembling a violent accident much more than a battlefield maneuver. Its best chance of survival when facing an infantry line that won't break up would be - just as it would for a horse - to hold the charge before impact. The main force of a cavalry charge has - despite Hollywood depictions - never been physical but rather moral. (Goldsworthy, A. K., 1996, The Roman Army at War, p. 230f.) [Answer] It would mainly depend on the morale and training of each side. Some human armies of the appropriate culture might panic and run away if attacked by a charge of unicorns, because it would seem to be a supernatural event to them. As another writer mentioned, the opposite could be equally true: the unicorns may be the ones who are likely not to go through with the charge, or to break early. Of course, if one side does run, unicorns will be very good at running away from men with swords, while humans trying to run from unicorns will have a very hard time. Apart from one side breaking and running, the fighting skill, discipline, coordination and tactics will also be a big deal. Either side might be superior, depending on the details of how they fight, and how well. You could try using [*Dominions* *4*](http://www.illwinter.com/dom4/) to run simulations with various attributes for both sides, to get results for various situations, and to give you a basis for choosing what attributes you want your unicorns to have to be consistent with the results.  [Answer] Unicorns are magical! Of course they can survive it. > > A unicorn is a huge, strong horse with **magical** powers and the tusk of a Narwhale > > > It seems clear that if you have magical powers and a horn, that one of the magical powers is going to be the ability to skewer things with the horn without taking massive head damage. Presumably, also, as with any magical weapon, it is incredibly tough and achingly sharp, so it will pierce any feeble medieval armour. Also, the unicorn is magically strong (and just look at the neck muscles in the picture!), and can fling the impalement victim(s) off it's horn through the air, without noticeable effort. If you have a magical mythical beast on your side, what hope does a mere medieval footsoldier have? [Answer] It would be just like a regular old cavalry charge, but at least slightly less effective. Mounted knights carried lances which had a much longer reach than unicorn horns, and a human rider can also carry a wide variety of weaponry. Once in a melee, a unicorn cannot do much with its horn, while a human rider can chop at his enemies from above. So, if the unicorns had riders on them, then it's no big difference from any historical cavalry, and if the unicorns didn't have humans riding on them, they would be less effective. (Assuming that unicorn biology is similar to the horse except for the horn) One single factor, however, could put unicorns into an advantage: if they would be much less fearful than horses, or even humans. Battles were not decided mechanically by a fight which lasts to the last man: armies almost always broke into a rout when losing 20-25% of their men, sometimes even much less. [Answer] If the unicorns are intelligent, their horns are tough enough to take multiple sword blows, and their horns are approximately as long or longer than the infantry's effective reach (sword + arm, extended to a length where the weapon is a real threat), then the infantry is toast. The battle goes like this: unicorns charge in tight formation. For each unicorn, if the infantryman in front of them swings, they block it with their horn and stomp the guy with their hooves. If not, they skewer them with the horn (which, unless shockingly dull, would easily penetrate chainmail). The formation then turns and gallops away. Since unicorns are presumably fast and have considerable endurance (like horses), they can attack any part of the formation that sticks out, where the escape part is easiest. If the infantry is exceedingly good at starting with a tight formation, unicorns could choose to go on a semi-suicide charge to break the formation (was done on occasion with warhorses), after which the following unicorns could attack the vulnerable infantry. If, on the other hand, the infantry has considerably better reach or can cleave through the unicorn's horns, and also has a numerical advantage, then the infantry has a winning strategy: pack warriors in tight formation so that at least two of them can strike any incoming unicorn. Both aim for the neck, one high and one low. Most of the time, the unicorn may kill one of the soldiers, but the other one will kill the unicorn. (This is why pikemen rendered cavalry almost obsolete except for chasing down fleeing soldiers; any well-organized unit would present a forest of sharp metal points to any incoming cavalry. Either way, if one side outnumbers the other hugely, the larger army will win; the question is really by how much you need to outnumber the other. If you're going for some sort of heroic fantasy setting, probably ten-to-one men to unicorns would be a tense battle, assuming nerves held on both sides and neither had a big tactical advantage (of the sort described above). For ideas about how the two sides should try to maximize their chances, you can read about infantry and cavalry battles and tactics. (The Greeks, esp. under Alexander the Great, had very effective [wedge-shaped formations](http://en.wikipedia.org/wiki/Companion_cavalry) of cavalry.) [Answer] Horses are not rutting Elk. Their necks are not evolved for impacts. Of course a unicorn *may* be designed to impale things with its horn. That's a world-builder decision. If you want them to take out footsoldiers, then they can. Use magic to handwave away any difficulties. [Answer] Cavalry charges with horses do not work against formed infantry in lines because the horses will not run into something that looks like a wall of their own volition. They will instead stop, and turn aside. Even without horns, a 'kamikaze' horse will break into a line or square. I recall a story of a horse being shot and killed in a charge and the body crushed in the square and disordered it, allowing it to be broken So if a unicorn reacts like a horse, it would stop to 'fence' with its horn when faced with formed infantry and its momentum would not matter at all, unless the line broke. Only if a unicorn would allow itself to charge that solid seeming wall would they be any better than horsemen, and then the horns don't matter as the mass of the body would be sufficient. [Answer] One thing to remember, horses and therefore unicorns do not have front facing eyes like us primates... this makes aiming and slashing a real difficulty. That's why (among many other reasons) things like elk and deer have great big horns that splay out. If your unicorns are mounted and directed then that will significantly improve the odds in their favor. I would however point you to the wikipedia article on charging as below. ## [Cavalry charges](https://en.wikipedia.org/wiki/Charge_(warfare)) The shock value of a charge attack has been especially exploited in cavalry tactics, both of armored knights and lighter mounted troops of both earlier and later eras. Historians... have shown that when correctly prepared... by standing firm in face of the onslaught, cavalry charges often failed against infantry, with horses refusing to gallop into the dense mass of enemies, or the charging unit itself breaking up. However, when cavalry charges succeeded, it was usually due to the defending formation breaking up... and scattering, to be hunted down by the enemy. It must be noted... that while it was not recommended for a cavalry charge to continue against unbroken infantry, charges were still a viable danger to heavy infantry. Parthian lancers were noted to require significantly dense formations of Roman legionaries to stop... However, only highly trained horses would voluntarily charge dense, unbroken enemy formations directly, and in order to be effective, a strong formation would have to be kept – such strong formations being the result of efficient training. Heavy cavalry lacking even a single part of this combination – composed of high morale, excellent training, quality equipment, individual prowess, and collective discipline of both the warrior and the mount – would suffer in a charge against unbroken heavy infantry, and only the very best heavy cavalrymen throughout history would own these in regards to their era and terrain. [Answer] Longswords and chainmail? The unicorns would massacre them *easily*. I'll make the assumption that these are military bred unicorns who are trained to charge and have necks and skulls designed for impact, as well as a magically tough as strong as a rhino. So something like soldier ant vs worker any range. First, cavalry were feared because they had the advantage of **strength**. The horses added a lot of momentum - mass and power. Imagine a motorcycle colliding with a pedestrian. The engine gives it more power and the combined weight of the driver and bike gives it more power. Cavalry, without the horn had enough power to knock someone down and badly injure them. Second, **height**. It's easy for a mounted person to strike an infantryman's neck as opposed to the infantryman striking a horse's neck. Assuming these are war unicorns, they likely evolved necks and skulls designed for impact. They would be much harder to kill with a blow to the neck, compared to normal horses. Third, **reach**. A longsword would never reach past that horn. Even a spear has trouble against a typical cavalry charge. A longer polearm like a pike might be needed. Fourth, **chainmail doesn't protect against piercing attacks**. You can look up how chain fares against spears and arrows. Chain is designed to protect against blades like swords and axes, to keep soldiers from losing a limb. Maybe if they had something like lamellar armor, they would fare much better. Even hardened leather might do better than chain. Finally, **intelligence**. Unicorns may be sentient or at least more intelligent than war horses. Even the dumb ones have natural control of their feet and weapon. They can fight naturally, easily jumping back, dodging with animal instinct, and then spearing through rows of infantry. So I'd say that the infantry would have a devastating defeat in such gear. If they wore non-chain armor and had pikes, they might have a chance. But let's look at it this way: Mike Tyson would lose against a gorilla. And a trained unicorn is a scarier opponent than a gorilla. [Answer] As stated above, an army of sword-wielders might not fare well against cavalry, especially one with pointy horns. But why would anyone attack horse-like creatures with swords only? There are proper tools for killing cavalry, for example halberds: <https://en.wikipedia.org/wiki/Halberd> Imagine a spear with the end thrusted into the ground, the pointy front pointing upwards and forward to the charging cavalry: When a horse meets the tip, the tip will stab the horse but go through resulting in mutal destruction as the dying horse still tramples the soldier. Now, with some sort of bar on the spear, it will go partly into the horse but then stop, instead lifting the horse like deadly pole vaulting. With the unicorns horns, the pole vaulting part might not work as the halberds might have to be longer to protect the soldiers from the horns, meaning that they may have to hold the longer halberds at a too shallow angle. But they might just use stronger shafts that can instead bear the onslaught and transfer the kinetic energy into the ground? This way, the next wave of unicorns would first have get through a wall of their friends that did not make it. [Answer] A lot of people saying Pikes/halberds beat horse/horn but riders can use lances/pikes etc themselves. In a world in which unicorns exist there will effective tactics on both sides for different situations/geography in attack & defence. Horn can be boosted with metal encasement and/or horse helmet. Unicorn can be armoured to protect head & chest. Mithril TM, the half as heavy but twice as strong metal perfect for this LOL. In this scenario unicorns are not just a horse with a horn but a horselike creature that has evolved to have a horn. Means it's either a very aggressive herbivore (territorial/mating fights within own species) or it's an aggressive predator, maybe carnivorous but probably an omnivore. It's horn is strong yet flexible, it's skull & neck is adapted to bear the horn. In addition existence of unicorn in a military body means training, breeding for directed aggro, strength, horn length. Unicorns if not herbivore prey animals but somewhat predatory themselves (therefore likely at least a bit smarter than the horse) more likely to not baulk at formations of soldiers. In a world where they existed they would have advantage over horse through horn alone adding that extra bit of spice. Force of impact/weight of unicorn/s trength of neck could mean horn getting stuck no more a problem than sword or axe occasionally getting stuck. Even if gets stuck, the rider can assist. In my world Elves tamed & utilised the unicorn long before man, and man started riding horses in emulation of the Elves, not having access to the unicorns. If the unicorn is sentient or semi-sentient that could be a choice the unicorn makes. It will serve just about every Elf ...but only a few humans are found worthy enough (not virgins necessarily, but spiritually pure/pure at heart LOL). If unicorn chooses the rider and a mindmeld bond is necessary/is formed the unicorn & rider will be way more effective than a horse and rider. Now Unicorns vs Centaurs is what I want to see. [Answer] The unicorn charge would fail. Unicorns might be strong and brave, but once a unicorn has impaled a soldier in the front rank it would have a 300 lb weight stuck to its horn. That weight would drive the horn of the unicorn into the ground allowing the soldiers to kill the unicorn while it was trying to scrape off the corpse. [Answer] ## You will either have a proper unicorn charge, or a proper line of infantry thusly prepared, but not both... **Why you would have the infantry line, but no charge:** The combination of mail, shield, and longswords were only owned by knights and similarly well equipped men-at-arms, meaning that this equipment was not generally used by your normal rank-and-file infantrymen, but rather men who also owned war-horses. So what your unicorns are actually facing are not "infantry" per say so much as dismounted knights. Contrary to popular videogame mechanics knights are not actually glued to the top a horse. They in fact often fought on foot when the need arose; so, they would strap their shields to their backs, leave their lances and horses behind, and then go off to fight where their horses could not go: typically in difficult terrain, urban, or castle environments. These leads to a very interesting conundrum. If the knights abandoned their horses and lances, but have the rest of their gear, it means that they have gone somewhere that horses, and by extension, the unicorns can not go. So for them to have put themselves in this situation implies that they deliberately took to foot to get onto some castle wall, or steep ridgeline, or bog, or something of the sort to seek safety from the unicorn threat. So, wherever they are, they are somewhere that the unicorns can not charge, and probably can not even reach if they tried; so, the idea of a unicorns being able to charge this infantry formation is VERY likely a moot point, because knights would only be thusly equipped against a unicorn threat if they 100% believed they not be charged. **But let's pretend you have a situation where the unicorns can charge the knights...** Let's pretend that your knights have abandoned their horses and lances to climb up onto a steep ridge to get away from the unicorns only to find out that there was another way up and the Unicorns are now charging them from behind. How would your knights react? For this scenario to happen, there are two pretty safe assumptions you can make: One, the knights perceive the unicorn army to be too big of a threat to risk engaging in an open field battle on horseback, and two, by leaving behind their lances and horses, your knights have scarified the two biggest advantages they would have for dealing with a charge that they already perceived as an overwhelming threat, but now they are getting charged anyway. This is such a horribly terrible situation to be in that I can not even begin to express how bad this is for moral. Normally military training is good for maintaining discipline, but in this case all that training is really doing is telling the knights just how screwed they are. Without any long-spears to counter, their imperative will not be to assume a battle formation, but to try to scramble to get out of the way of the charge. Some knights might try to assume a formation, but in the chaos, many others will be trying to run back to their horse to retrieve their lances, others will be running for the nearest trees or rivers just trying not to die. Some will try to join the formation, see everyone else scrambling away, then change their mind and run... the result will almost certainly be a very thin and poorly formed battle line, if not a total route, So... even if your charging unicorns could be stopped by a thick block of well formed longswordsman with good moral, this is just not a likely scenario... the panic would assure that you probably would not have enough depth or resolve in your formation to stop the charge. **The one possible exception...** When you remove shields from the equations all together, there was one warrior culture who at least preferred mail and longsword on foot: the gallowglasses of Ireland. These were fanatical warriors who sought heroic deaths for entry into valhalla; so, in battle they either prevailed or they got horribly slaughtered... either way, one could expect the battle to be over quickly. The thing about gallowglasses is that they were actually quite bad in a head to head open field battle. The space needed to swing a longsword is greater than you need to fight with a spear; so, each longswordsman would be having to simultaneously protect himself from many spears without having a shield to help in this endeavor. Instead, gallowglasses would normally be allocated to ambush or flanking maneuvers where the flexibility of the loser formation could be used to your advantage. What does this have to do with a unicorn charge? Well as it turns out, loose infantry formations have a long history of getting slaughtered by cavalry charges. The space between the gallowglasses mean that the horses (or in this case unicorns) can recover some of their momentum between trampling soldiers; so, if the unicorns maintain a tight charging formation against the gallowglasses, then they will simply trample their way in on one side of the army and out through the other without ever being slowed down enough to give the infantry much opportunity to fight back. ]

[Question] [ Merpeople, along with other similar underwater humanoids, are often depicted as living in great cities beneath the waves. These cities have many positive things going for them: plenty of real-estate, easy to build upwards, fairly consistent weather, and lots of access to water. While these cities are often depicted as being laid out in a similar way as surface cities, this seems like a poor choice for defense. Walls and gates are trivial to swim over, and bombardment from above is a constant threat. Furthermore, traditional means of both ranged defense and attack may be useless underwater, given that projectiles can't be fired as effectively through water. My merpeople are unsatisfied with this arrangement, and have commissioned their finest mer-architects to build them a more defensible mer-city. Their mer-king has approved the plans and the mer-chants have accumulated the money to build. What kind of threats do the architects need to keep in mind, and what sort of fortifications and defenses should they build to keep the city safe? The merpeople in this world have fish-like lower bodies and humanoid upper bodies. they've got primitive lungs that allow for limited activity outside of the water but breathe primarily using gills. Technologically, they aren't terribly advanced, perhaps at the same tech level as the late Roman empire. They've got some metalcraft, using undersea volcanoes for forges. They don't have much in terms of explosives or gunpowder, though the mer-king is willing to invest in researching such things if they're the best bet for defenses. They have had significant success domesticating other undersea creatures, so sharks and whales are available as resources. The king is primarily worried about attack from other merpeople, as well as some other unsavory underwater humanoids. He's got trade and contact with the surface folk, who are about at the same tech level as his kingdom. They fight, occasionally, but the combat is mostly restricted to the surface of the ocean, leaving the underwater cities untouched. [Answer] **Make open water access difficult.** If the merpeople need to breath air, then what they need is a very defensible surface entrance to their city.  A deep cave with a single entrance near the surface allows for simple surface defences while maintaining underwater access. With the entrance being surrounded by a reef or an atoll, any invaders must wade through shallow water in order to approach the entrance. **Build the city inside a cave.** Being deep underwater, sunlight is already not a typical luxury for the Merpeople. Lack of sunlight being the main disadvantage of living inside a cave, the cave dwelling Merpeople will not suffer much.  [$^{Source}$](http://www.pickywallpapers.com/1024x600/digital-art/great-underwater-city-wallpaper/download/) The cave have similar benefits as a cave on land. It protects from all directions and allows for focusing defenses on the entrance of the cave. If no cave is forthcoming, a deep trench with a constructed roof will provide a similar benefit. The roof could be **grown from coral**, which has [long been used for construction](http://en.wikipedia.org/wiki/Coral#Construction). [Answer] **Nets** Simply enough your mer-folk have a rich number of options for appropriate military netting. Net walls perform some degree of passive work of course but still suffer from the 360 degrees of movement in water. However trap nets could be designed with ballast (anti-ballast?) to deploy or be launched from the city; these nets could entangle enemies and the floats (anti-ballast I guess) would drag them to the surface. Additionally whale/shark riders could work in teams to net enemies and then cut the nets loose from their mounts (whose strength overcomes the floats) again dragging their enemies to the surface. Depending on the materials used (we have merfolk so I'm guess some fantasy is involved) the netting materials could be rather exotic like "Tempered Jelly Fish Tentacle Nets" very strong and causes pain to those caught in the net (preventing easy escape with something like a diving knife). [Answer] Since the mer city is effectively under threat from all angles, a dome is the most likely measure of protection. (If creatures or high tech opponents have the ability to tunnel, then the enclosure should be a sphere). The dome provides direct physical protection against threats ranging from depth charges dropped from ships on the surface to torpedoes launched from around the perimeter. With small and protected access ports, the threat from enemy commandos (either merpeople or human divers) can also be reduced. The dome also provides a naturally strong structure to resist overpressure from explosive devices, and the curved surface can reflect shock waves, to a certain extent. As a bonus, this uses the minimal surface area to enclose the maximum volume, something the treasury should be pleased with when looking at the bill. The bill itself will be huge since the dome must be immensely strong. Even though it is supported by the volume of water enclosed within, the effects of shock waves and explosions will be hugely amplified by the physical properties of water (at 800 x denser than air and being incompressible, shock waves will move much faster and will not be attenuated like they would be in air). The deeper you are, the more static pressure is on the dome, to begin with, so the pressure differentials from explosions outside the dome will also be hugely amplified. The primary threat to the dome is pressure, so materials which have high compressive strength must be chosen (materials with high tensile strength like Kevlar or Graphine would require some very unusual building techniques to effectively use their strength). The dome will also have to be protected from the environment, just as structures on land are. The RMS Titanic is already decaying due to the presence of bacteria which "eat" the iron of the ship, so the outer surface of a metallic dome would need to be coated with some impermeable, non reactive substance to stop the effects of bacterial decay or just ordinary corrosion due to being immersed in salt water. The King of the merpeople will be annoyed at the amount of gold needed to cover the dome... Other possible substances to build the dome out of could include concrete, diamond or perhaps more simply using electrical current running through a wire armature outlining the shape of the proposed dome to cause minerals to precipitate out of the sea water and form a natural sort of "concrete". This is similar in principle to how some sea creatures accumulate shells, and may be a better "fit" for how the mer people actually build things. A dome built in this fashion will be much cheaper, but not as strong as an engineered dome built out of "our" sorts of materials. [Answer] Domes seem obvious but also expensive and perhaps a bit technologically beyond your mer-people. So I am going to break this down by threats and how to counter each. **Anti-Artillery** Artillery in the underwater realm would best work if it is literally just dropped from above...the resistance the water creates would make launching it in a conventional matter ineffective as the range would be very very short. So. You have boulders dropping from the sky...err...upper ocean I guess. Diverting is the best option here. I would suggest attaching strong slanted covers to the to the tallest structures in the city. The structures should funnel the stones or whatever is being dropped into certain locations within the city or outside the city perimeter (in a large city you probably need to do both). Just make sure people know where not to be during the fighting...*squish*. **Anti Personnel** Here is where you can get real nasty on defense. Create nets made of concertina wire. This is essentially barbed wire...with razor blades attached instead of barbs. Depending on visibility you can combine that with stirring up sand and grime from the bottom to make it harder to see...or camouflage it with growing sea grasses. **Anti-Vehicle** *Boats:* boats/submarine are going to be tough to stop...if strong enough they could break the razor wire nets...but the wire could also tangle propeller propulsion. Again...in a 3D environment I think nets are going to be a good bet. For boats you could simply create big chain nets to disable them. *Tanks:* Just because you can attack from above doesn't mean ground based attacks are worthless. You can still have tanks (think battering rams with the roof) along on the ground so trenches and walls and barricades will still have their place they just won't be quite as primary. [Answer] Keep in mind the enemies gate is down (relevant username). The principles which apply from Ender's Game are quite relevant here. Single hardpoints are very difficult to use to defend an empire when you have multiple dimensions. If the king has territory which is also needing defense, any of these can be bypassed. You cannot defend something easily from 3-directions. This might seem obvious, but is the fundamental assumption on which *all* defensive systems must be understood for a city which can be easily attacked from most directions (not below, unless the city is floating). So the first thing the king needs to determine are: * Can a singular fortification be the entirety of defended territory? * How long can the city sustain itself if under prolonged attack? You might take advantage of existing natural geographical structures. Another answer addresses caves, but keep in mind underground mountains/valleys are also much more defensible - what you want to do when using these is dictate how your enemy approaches. Shallower areas will help avoid the angle of attack from above by allowing you to "wall" the distance from floor to ocean surface. Areas along shoreline with steep dropoffs provide considerable defense against other primarily underwater enemies. Keep in mind, in some sense, the more defensible it is, the easier it is to isolate and place under siege. Next, determine whether having an early warning network is beneficial or feasible. There are lots of whales which can communicate vast distances underwater which would serve as a patrol network. Keep in mind the further you go away from your city the number of patrols required to have the same density goes up nonlinearly. You also want to have a very mobile army to respond to attacks. Since they can come from many directions easily a military which can be easily mobilized will be a huge asset. [Answer] Not sure if you can easily erect defensive structures that would be too effective here...most things can easily be swam over/around and don't provide much for cover. So I'm not sure if fortifying an underwater town is a feasible venture (a dome is in other answers, but I believe this is far too expensive to build from scratch and potentially far outside of their technical abilities). I believe you are going to be in a 2 phase defensive approach instead. First phase - The simplest defence of this city is keeping it hidden. A network of forts on the sea floor along with floating 'forts' suspended in the waters will help them keep it this way. Simple idea...the mer-city is surrounded by forts (or whatever they might be) that detect and intercept any incoming creature that shouldn't be there. Keeping small yet fast strike teams (shark use works here) that move to intercept any invader so they cannot locate the city is important. Traps, barbwires, nets, and any other deterrent these mer-folk can come up with can be employed here. The forts need to be positioned so they have good lines of sight and only have one or two entrances (bottleneck defence, a narrow opening defended by a series of tridents would not be easy to push through). They need to be far enough away from the city that they are out of sight, but still be close enough for the guards to travel to and be able to communicate back to the city quickly. Second phase - A castle. Your network of forts are going to intercept most small threats, but a larger 'invading' force will be able to overpower it. When the forts (or scouts) detect an incoming force that can overpower the forts, the alarm in the city is raised and people get out of the city and into their castle. Kinda the 'helms deep' approach to defence...a castle well stocked with supplies can be a place to hide and wait out the attackers. Castle is best as underwater caves (natural or dug out by the merfolk) with narrow tunnel entrances that can either be defended with a series of tridents, or outright blocked off from the inside (a large bolder that normally sits out of the way can be pushed from the inside and block off the tunnel. It's got to be big enough to hide away the population of the city and hold enough supplies to keep them alive for a year or so. Tubes with 'straws' can reach up to the ocean floors from the caves to keep fresh water (and oxygen) flowing through the 'castle caves'. [Answer] Some ideas for defending the mercity against attack that do not involve fixed, solid fortifications. 1. **Black smoker.** These undersea chimneys expel dense clouds of mineral and sulfide laden water. Looking down from above one would see only opaque clouds of white or black. Additionally the sulfides and chemical content of the expelled water would be tough on water breathers. I could imagine capped smokers which could be uncapped in emergencies to release plumes of toxic hot water. 2. **Oil well.** The merpeople could have oil wells which they open during battle. This would also contaminate the water column above the city, but not as much as the soluble sulfides from a smoker. An oil well would be useful against attack from above - after the surface was slicked with oil, floating "bombs" could be released to ignite it. This would be good against boats. It would be even better against things which must surface to breathe. It is not specified if the merpeople in this scenario breathe air or if they have gills. If they breathe air and have a supply in the city, a fixed surface fire fed from below would make it very difficult for air-breathing aquatic attackers based at the surface. 3. **Clathrate / natural gas / air bubbles**. Clathrates are solid forms of methane ice which can degenerate into gas with heat or shock. A column of bubbles would be a fine defense against aquatic attack from above. Bubbles occlude vision and also sonar, and dampen sound transmission. A thick enough cloud of bubbles reduces the density of the water column. A dense column of bubbles intercepting a swimmer would cause the swimmer to fall through it. Some people think the Bermuda Triangle phenomenon is caused by dense clouds of methane bubbles which come up under ships, causing them to fall into the sea. A fixed source of bubbles could hide the city all the time. 4. **Kelp.** Siting your city in a kelp forest means it cannot be in the abyss. But 150 feet is deep enough for a respectable city. A kelp forest city would look extremely, extremely cool. Kelp is not very dangerous itself. But you cannot see through it or sonar through it. Attackers would be at a disadvantage in that defensive measures (see #7) will be all over them before they know what is going on. 5. **Currents.**. Siting the city beneath a strong current would be fine protection. Attackers sallying down from the surface would be swept sideways by the current; likewise bombs. There are places where underwater topography channels water movement to produce currents of this sort. Perhaps the merpeople construct such or augment existing natural features. A strong lateral water current would be more penetrable than a wall, but you cannot batter a hole through a water current. A water current of this type would sweep away attacks intended to poison the water. Bonus: if you pee while defending your city no-one will know. 6. **Jellyfish.** Over the city loom five colossal and many, many smaller jellyfish, their tentacles hanging down. These creatures are almost impossible to kill. Even dead and in pieces, their tissues continue to sting. They are fed by tenders wearing special suits and so converge hungrily on anything which gets close to them. Any attacker traversing them must also wear a protective suit, which looks really stupid. Prince Namor types in their scale speedos will definitely go down at a distance and come in laterally. 7. **Octopi.** How can you have a merperson fortress without trained octopi? These defenders sally out from their holes and use their 40-foot tentacles to seize mounted attackers approaching laterally. Oh, you think your sword will slice those tentacles off, do you Mr. Meragorn? It turns out chain mail flexes wonderfully with the tentacles and octopi are so strong the added weight means nothing. Hmm. I see the attackers have brought their anti-octopus measures... [Answer] What I naturally think of is to build the city into a coral or rock wall, the same as if humans build their city onto, or into, a mountain side. If possible, build it into a wall as close to the surface of the water as you can. Even better if the wall has a concave shape where the city is. The city mer-people get plenty of light (possibly making it hard for the deep mer-people's eyes to adjust) The attackers may also have to let their body adjust to the elevation if they usually live very deep. Also, the city is now naturally defended from enemy mer-people by the water surface above and the rock wall to the rear, leaving forward and below to defend. At first I was just thinking houses and buildings on the face of the wall, but it might also be possible to find a cave system with limited entrances (like a hole), or have the city within a large crack. [Answer] Inspired by DoubleDouble's idea of 'build it as close to the surface as you can' to give little up-down manoeuvring and so the defenders have the advantage of being used to lower pressures and higher light levels: Build it only a couple of storeys below the water surface - the walls only need to reach up as far as the surface is - a dome is not necessary as the merpeople (I assume) cannot breathe air and are unlikely to be able to leave the water to go over the walls. Alternatively, build it in a very large lake a couple of miles from the ocean. This lake is only accessible via an underwater stream, the entrances and exits of which are heavily guarded, and maybe a few emergency exits that lead from the lake to a couple of meters away from the ocean (never live in a place with only one exit). ]

[Question] [ Could underwater creatures with the intelligence of human cave men or possibly the intelligence of apes create technology (that is, more complex technology comparable to what we have now rather than simple stone age equivalents)? If so, what energy source and materials would they depend on, given that they don't have any access to materials on land. [Answer] Technology could develop, arguably would automatically, if aquatic creatures reached a certain brain size. but.. The first major impediment to the formation of technology underwater is the lack of oxygen. Water in general is not an efficient solvent of oxygen for example, a human would need gills several times their body area IIRC something over 15 square meters in order to exact enough oxygen from even well oxygenated water. There are plastics that form osmotic membranes in water that selectively pass gasses but not water. Ordinary polystyrene will do this. But you need such a large surface area that nobody had been able to make a practical breather. There is also the problem that oxygen content varies significantly with depth and vertical and lateral currents. Sometimes, fish hit a dead zone and simply suffocate before they can swim out. That's the biggest brains in the sea belong to aquatic air breathing mammals. Gils just won't cut it. The biggest non-mammal brains belong to octopi who "breathe" by inhaling a lot of water, compressing it then jetting it out again. Even so, they are limited to brains much smaller than mammals. Postulating alternative chemistries really doesn't help because such chemistries won't have the energy flow of an oxygen based one and therefore couldn't support large, energy intensive brains. An ecology based on sulfur compounds, like those in "black smoker vents" won't likely support large brains. Better to postulate an alternate neurology which use a different and lower energy mechanism than electrically charged membranes. Can't think of plausible one off the top of my head. So, you're probably looking at something that is air breathing or as some other means of obtaining excess oxygen e.g. has symbiotic plants that generate or cache oxygen for it in a form like hemoglobin. Air breathing doesn't require land. Many surface dwelling fish have a primitive air breathing system from absorbing oxygen from swallowed air. Lung fish breath through their gas bladders which are attaches to their digestive track. Something similar could evolve eventually to air breathing "fish" with no land ancestry. The other problem is the vast majority of the ocean floor is a desert. Once you get down passed 60-70 meters, there is no light for photosynthesis and away from the continents, there isn't a lot of minerals, like iron, floating around. The seas both in terms of area and volume, are relatively dead. So, the planet would need broad, shallow (<100 meters or so) oceans like those which dominated earth in the permian. Hands or manipulators are not much of problem. If you look at fish, octopi, anemone and other organisms that live in and on coral reefs in shallow water, it's clear that streamlining isn't much of selection pressure. Speed is important in the open but in more confined spaces, the ability to maneuver precisely, anchor and push-off seems more important. Octopi, for example, have manipulators on par with human hands. Besides there are options to hands. You could have a hive species that uses swarm tactics, like bees, ants etc do, using the coordination motion of dozens of individuals to provide all the control vectors. Swarm robots are all the rage now because it's a lot easier to control and object with a lot of small controlled shoved that trying to control it with large vectors arising from a single point, e.g. a human shoulder joint giving rise to all the vectors of the arm and fingers. So, once you have big brains and manipulators what could you make? Aquatic species primary senses would likely be those that work best underwater, sonar, electrical fields, combined smell/taste, ambient vibration detection etc. Visible light vision would be a secondary sense. The underwater senses would likely give a sentient species something close to x-ray vision. Dolphins and whales appear able to scan the insides of living animals with their sonar. Likewise they can detect buried objects. Electrical field detection likewise gives the ability to detect living organisms and some structures in sand and coral. Smell and taste sensors wouldn't be limited to the mouth or nose but could be spread out all over the body or concentrated in manipulators. In short an aquatic species could extract a lot more detail about objects in their environment, especially the chemical, electrical and internal structure, than air/land based could. So, they could examine their environment and manipulate, the question is why bother? As much as we like to flatter ourselves, intelligence isn't always an automatic game winner, especially when it comes from such high metabolic overheard. It requires a payoff. For humans, it was cooperative hunting/scavenging for meats and fats, combined with stone tools to cut up tissues and bones that our muscles, jaws and teeth could not. Lastly, fire let us digest a wider range of nutrients without any metabolic or structural specialization similar to that found e.g. in vultures. It really looks like the primary driver of large brains is not technology, but social coordination. Large brains let animals work in larger and more effective teams. E.g. wolves, meerkats, dolphins etc all have large brains compared equivalent more solitary species but they don't use technology as we think of it. (Dolphins seem to use their large brains to plan and carry out gruesome coordinated military campaigns against other dolphins, largely for kidnapping females. Most dolphins are killed by other dolphins instead of predators. Those scars are from bar fights. "Flipper" they ain't.) In the same way, large brains might get started in an aquatic environment because of a need for coordination. That could be some form of hunting but it could also be obtaining oxygen or creating reefs for symbiotic food species and defense. Imagine a bunch of air breathing octopi, whose primary primitive technology was building coral reef structures to provide air, food and shelter. From there, they could figure out how to make cutting weapons from coral. Tools underwater would be much different than we think of them. For example, swinging a lever like an hammer or axe, is not efficient under water because water resistance robs all the energy. Plus, rapid high energy motions stir up silt and generate vibrations that telegraph one's position. Instead, grinding, raking and drilling would be the orders of the day. Repetitive motions over short ranges would work better than rapidly moving levers. Water jets, with or without injected abrasives, could take the place of knives and saws. Various forms of bicarbonate and biosilicate would likely take the place of stones. Likely, a form of coral topiary would be an early technology on par with making mud bricks was for humans. Rocks, especially specific types like flint, might be hard to find because in the sea, everything gets covered with silt and biomatter. On land, plants needs a certain minimal amount of soil and won't grow on bare rock save in very humid conditions. In the ocean, however, plants, fungi and sessile animals simply use hard objects as anchor points. On land, a pile of flint will have not plants it and will be easy to spot. In the sea, it will be covered up with something. Nothing will just laying around. On the other hand, as noted above, sentient sea life can probably probe through materials so perhaps it wouldn't be that much of problem. It's important to remember that you don't need as strong of materials to build underwater as on land. Building on land requires materials with great compressive strength because air is compressible and provides little buoyancy. Air provides no structural support at all. All the strength comes from the materials. (Foams with trapped air are an exception but they are weak because they compress.) On land, to lift something you have to put a lot of compression resistant mass under it e.g. stone, steel etc. Under the water, you attach a balloon to it and lift it up. If you want something to resist compression, you make a sealed cell of a high tension material and then let the incompressibility of water carry the load. The structures of an underwater civilization would likely be lightly constructed and gain strength from buoyancy and incompressibility. The equivelent of a skyscraper could be just a bunch of netting will a balloon of gas or low density oil at the top. The problem wouldn't be keeping it up, but floating away. Fire is not as important as we think. It's important to humans but that is because humans used fire to pre-digest foods and for light. In the sea, Pre-digestion could be done chemically (like a ceviche) or by enzymes borrowed from symbioses. Light would not be a big benefit because sight would be a secondary sense and in any case, could be generated by bioluminescent sources. Neither is metal. Modern humans existed for 40,000 years at least before the first metals, and the civilizations of Meso-America built vast cities without using metals for anything but decoration. Metals are not necessary to technology. The primary use of metals was as wedges of different forms, e.g. knives, plows etc., but with slow motions like sawing, grinding, raking etc being the primary means of transferring energy, a wedge would not be quite as important. Hydraulic pressure could take the place of wedges when needed, especially if speed was not as important. But, an aquatic species could develop metallurgy using electrochemistry which would be easier to develop in seawater, especially given they have electrical field senses to begin with. Magnesium is abundant in sea water and easy to extract with even primitive electrodes. One could postulate a sentient species that has a anemone like symbiotic that radiates a powerful electrical detection field. The sentient starts out just anchoring the symbiotic around as a kind of early warning system. Selective breeding leads to stronger and strong field generation until they end up with something like an electric eel. (Which is how electric eels evolve.) Now they have a powerful, controllable and regenerative source of electricity. They would already be aware of calcium carbonate and silica precipitation by electrical fields so electrical metallurgy would be a short step. They would also have an advantage in long distance communications. Sonics carry for hundreds of miles in the oceans and can carry multiple bands at the same time. Even at very primitive levels, they might coordinate millions of individuals over tens of thousands of hectares with the ease of which humans coordinate a small village. I could imagine a civilization of highly cooperative, air breathing, squid-like critters, who used swarms to carry out manipulations and with strong division of labor e.g. that might have some dedicated to shuttling air bubbles, or a chemical oxygen store, to and from the surface, all coordinated over long distances and in large numbers by electrical fields and sonar. Their primary structures would be made of carbonate and biosilicate foams, made buoyant with waste gases and strong by filling the cells with water or oil. For mechanical energy, they could harness currents like a combination waterwheel, windmill. Humans are so sight oriented that we have dull senses of smell, taste, hearing and touch compared even to other mammals. It takes us centuries to divine chemical compositions but a sentient species that evolved in salt water would be like living chem lab equipment by comparison. They would use those sense to develop a bioelectrical and enzyme based technology. They would probably skip over iron and other ferric metals and instead go to aluminum and magnesium alloys, then perhaps various graphemes. Their technology would emphasize skill, senses and complexity, all made possible by living in seawater, over velocity, shock and heat like most human technologies. They might have trouble getting into to space because of their relatively low energy technology but then again they might try alternate technology like balloons that could rise to the edge of space and then form into sails to catch the solar winds and the planets magnetic fields. (There are similar designs tossed about here on earth but we haven't bothered thus far because we know a lot about fire.) Once in space, they would have an easier time of it because living underwater is closer to microgravity than living in air. So, yes it's fairly easy to postulate a plausible technological species once you stop seeing fire as something special and necessary. Once they have enough oxygen or other source of energy, the need to grow big brains for organization, manipulative organs and something to profitably manipulate, off they go. [Answer] There is an interesting science fiction short story by James Blish that tries to answer this question. It's titled "Surface Tension" and can be read in [Galaxy Magazine (August 1952)](https://archive.org/stream/galaxymagazine-1952-08/Galaxy_1952_08#page/n5/mode/2up). The story proposes that technological life could develop under water, but not without a few challenges. Keep in mind that the life forms in this story happen to microscopic as well, so their struggles come from more than one source. The story presents three main challenges for the developing civilization: producing heat, creating stronger materials, and chemistry. **Producing Heat** Blish hypothesizes that heat produced under water would dissipate much to quickly, often resulting in explosions. > > Because heat produced in open water is carried off as rapidly as it's produced. Once we tried to enclose that heat, and we blew up a whole tube of the castle and killed everything in range; the shock was terrible. We measured the pressures that were involved in that explosion, and we discovered that no substance we know could have resisted them. > > > **Creating Stronger Materials** The above quote leads into the second issues that Blish presents. A source of heat is required to create stronger substances, but stronger substances are required to control the source of heat underwater. > > Theory suggests some stronger substances - *but we need heat to form them!* > > > **Chemistry** Finally, Blish surmises that chemistry would be difficult to develop in an underwater environment, mainly because it would be nearly impossible to maintain a solution at a constant concentration. > > Take our chemistry. We live in water. Everything seems to dissolve in water, to some extent. How do we confine a chemical test to the crucible we put it in? How do we maintain a solution at one dilution? > > > --- All of the quotes were take from page 13 of the magazine I linked to, but I recommended reading the entire story if you want to fully understand Blish's reasoning. [Answer] **Fire** The main problem with underwater technology is the lack of fire. Fire was a major component of everything from metallurgy to even flint working and fire-hardened spears. It provided light and heat and allowed people to move to areas where the climate would normally be far too hostile. Everything else can be worked around but without fire everything else is going to be really hard. There are some potential alternatives, for example thermal vents in the deep sea provide extreme heat - but there would be serious difficulties accessing them without coming to harm. There are some techniques and some metals that work without heat but the options are few and far between. **Hands** Hands would most likely not evolve underwater. Something like a sentient octopus might get some grasping ability but the arboreal lifestyle that leads to the development of grasping digits doesn't exist underwater. Even creatures like sea horses that spend a lot of time holding on don't need strong grasping hands to do it. This means underwater creatures are not likely to have fine motor skills or dexterity needed for effective tool usage. [Answer] I'm actually going to answer the question from the *opposite* viewpoint of TimB, if only because there *are* some loopholes to a lack of fire. They primarily apply to deep-sea civilizations, but still, they're moderately feasible. **Heat** Heat would be a very big problem for an underwater civilization. They might need to stay warm if they were in a cold climate but had not yet adapted to the cold, or if a sudden cold spell or ice age fell on the planet and drastically lowered temperatures. Like TimB, [hydrothermal vents](https://en.wikipedia.org/wiki/Hydrothermal_vent) were the first thing that came to mind for me. They exist at the very deepest levels of the ocean, and arise because of geologic features (i.e. underwater valleys or ridges where plates meet). They can sustain a lot of life! The first thing I noticed when I first saw videos of these vents when I was a kid was the tube worms and crabs surrounding them. Why are these creatures there? Well, the vents feed bacteria that perform [chemosynthesis](https://en.wikipedia.org/wiki/Chemosynthesis) - creating energy by using minerals from the vents. This creates a food chain that eventually attracts a wide range of life. **Light** To properly interact like a typical land-based civilization, this civilization would need light (I realize that a whole lot of deep-sea creatures get along just fine without it, but that's a bit boring, and user93 basically implied a civilization similar to ours, so I figured it's okay to ignore that very important detail). Some creatures use [bioluminescence](https://en.wikipedia.org/wiki/Bioluminescence) for various tasks, such as [attracting prey](https://en.wikipedia.org/wiki/Anglerfish). Others use it for the mating season (fireflies, anyone). The point is that there are some creatures deep in the sea that are at least partially bioluminescent (e.g. the anglerfish), and not all of them are animals. I would imagine that an undersea civilization could harness bioluminescent plants to create enough light to live comfortably. So deep-sea creatures could indeed find substitutes for fire, and although it would be difficult for a shallow-water creature to go to a hydrothermal vent or somehow capture bioluminescent bacteria, I imagine it could be done by creatures who have already adapted to places where those resources are available. [Answer] Absolutely a water breathing intelligent civilization could arise on an other planet or even on Earth under the right conditions. There are countless trillions of planets and moons in the universe but let's focus on Earth. It's proven that intelligence has arisen in the oceans. We know of two aquatic species that have intelligence that are off the chart. Although not water breathing the dolphin is likely the second most intelligent living animal on the planet. They're arguably more intelligent than a chimp. They have actual language and create names for one another via pitch frequencies assigned to individuals. The second aquatic animal to evolve intelligence is the octopus. Although not as intelligent as a dolphin it's certainly in the top 5 of intelligent animals. The octopus evolved intelligence probably because its body design isn't ideal for underwater hunting; it's not streamlined like a fish. It has to always out smart its prey and over time this adaptation improved. What is so interesting about the octopus is its ability to manipulate objects. There is a case where an octopus learned how to climb out of its aquarium and turn off a light simply through observation. Added with its intelligence I believe given a few million years the octopus could develop technology. They will often come to the surface for several seconds they have even been known to hunt on land. They are certainly well aware of the difference between water and this strange environment called land that they can't breathe. I believe it possible that in a few million years the octopus could create a structure in their habit that could sustain a dry air bubble environment. This structure if built properly could be the first step towards having the ability to create fire. They are conscious of the concept of fire and hotness through under water lava flows and thermal vents. If this is the case the sky is the limit and they could build virtually anything. They could build vessels to explore the surface and eventually start to wonder what is beyond. [Answer] **Heat/Fire** They could use underwater volcanoes as source of heat to craft metal tools. Probably not easy to handle but they could always find a way. This would also imply that only certain civilizations living close to the volcanoes would have this capacity. **Electricity** There is plenty of creatures capable of generating electricity. They could use those as "generators" In a more general view, consider they could develop some kind of bio-technologies, i.e. based on living creatures rather than machines. [Answer] Well, I believe we are looking at this question in the wrong way. It's not about the technicals, but rather the philosophy whether an intelligent life species can prosper in the ways such that it can propagate its species and can have mastery in controlling and modifying its environment. The question we should ask is: How did humans develop our technology? Is it that the universe in its 10 billion years of existence was always waiting for a living organism to appear who would have qualities such as ourselves? Our average weight, strength, life expectancy (if we were to live for one season like butterflies and equally intelligent would we be so advanced?), ability to detect air pressure vibrations in the 20 to 20000 Hz range and detect a minute fraction of electromagnetic spectrum (how we see) and able to generate upto 1000 N (this is just my assumption) of muscle force per individual (I assume the first machine have to be build by physical force, or if even if we are to use animal power then we should at least be able to tame them). Also, we should not assume that for an underwater organism to be advanced. It should be able to achieve the same things as humans did. For example, they should not necessarily have electricity conducting computers to maintain their information (some other information technology could be developed). In my view, if you get an access to an intelligent early man and an intelligent underwater species (assuming that you can communicate with both of them) and if you were to show them today’s technology, they would both be amazed in a similar way. (I said intelligent underwater species, not a dumb fish... There is no intelligent underwater species as advanced as an early man, not one I know of). Of course, the while you are giving them a demonstration the fish might think “Why the hell do I need a flying machine. I can already fly”. Also *[Anthropic principle](http://en.wikipedia.org/wiki/Anthropic_principle "Anthropic principle")* might be interesting to read. Well, I know many can disagree with me, but the same can be said about the existence of the aliens. [Answer] I assume you are talking about the planet [Kepler-22b](https://en.wikipedia.org/wiki/Kepler-22b). I will also assume you are talking about advanced technology. This question is a definite yes, though the environments are different. Water carries small amounts of electric charges, so creating electric technologies underwater would definitely be possible. Electricity would be 100 times more efficient on a water planet than on a planet like earth. Human intelligence didn't just happen, and it took several decades for nature to develop a specimen that could improvise and manipulate its surroundings. As intelligent as humans like to believe we are, we really are quite insignificant. We are one of the most capable species on our entire planet AT THIS TIME, however from observing water specimens such as dolphins (the most capable on our planet) they are very very intelligent. I believe what led the humans down the path to solving mathematical equations is thumbs counting began with sticks and drawn representations of objects. Mathematics led humans to being able to calculate educated guesses on our environment. Those educated guess lead to studies in the subject, then that created the education system we know today. For humans mathematics is key. If the species can not conduct a simple equation in mathematics it will never evolve into a species of recognizable intelligence. If a dolphin had thumbs I would definitely say they would be far superior to humans. \_\_ How an extraterrestrial life form would look on a water planet: You have three classes for survival in the water the species that live on top, in the middle, and on the bottom of the ocean. Those that live on top would be victims and would not have a very long life span, and this would play a large role in the intelligence of that species. Species that live on the top of the ocean are usually flat and floating on top to bask in the sun. Those that live in the middle would be very quick and agile, making their abilities of perception extremely high. For speed you would need a narrow face, fins, and don't forget for intelligence you would need thumbs. Species that live in the bottom of the ocean are not very smart on earth and I suspect that this is because of the water pressure. So I doubt intelligent life would ever live on the bottom. If intelligent life were to exist on a water planet I would say it would be a species able to survive in the middle and feed on those on top. (By the way, usually species that live on top are plants so this intelligent life could be either herbivorous or carnivores or both!) On earth: * Herbivorous are slow and not very smart. * Carnivores are extremely intelligent due to its survival instincts. * Omnivores vary in between herbivorous and carnivorous. --- If intelligent life existed on a water planet I would STRONGLY believe that the specimen would be much more intelligent than any land specimen. Even though a species is in on a different planet, the species would be VERY similar to life forms on earth. And when I say VERY I mean VERY despite the misconception that other people may have, though the species may be bigger, smaller, etc... It would pretty much all be the same. [Answer] Electric long lived octopus. The octopus people use their own electricity or that of domesticated animals to build seacrete, a concrete made by mineral accumulation. they purify metals by electrolysis. cold forging by slow pressure, molding by scraping. water will rob the energy of fast movements, projectiles, etc. better to grapple and stab or use nets. they can still use fire by building above the water level and using levers pulleys and son on to control the process. chemistry is hard underwater because everything is floating and dissolving. theyll learn to make polymer insulators on the above water structures. eventually theyll make hydrogen airships, high altitude wind turbines, and of course hydro. long before they get to that stage theyll use seaweed or leather tubes for hydraulic systems powered by waves. once in the air theyll want to explore the stars. theyll build remote controlled robots and send them on rockets to the asteroid belt to build an orbital ring to get them and their water heavy environment off the ground. then theyll see how humans eat octopussies and theyll eat us in return. you can ignore that last part, but I bet Id be delicious. ]

[Question] [ Imagine the whole universe is a simulation. This should include also the people living in the universe (so more Simulacron than Matrix). And now imagine there's a group of hackers who knows (or suspects) that they live in/are part of a simulation, and want to hack it *from the inside.* So they try to find weaknesses in the simulation code which let them then do things which are not meant to be possible. That is, basically doing magic by hacking the code running the world they are in. Of course they can't simply open up a terminal and look at the code itself (well, after sufficient hacking, they might actually gain that ability). That is, they are restricted to actions that are allowed in the world, but happen to trigger bugs (or features not intended to be accessible to them) in the software to cause things to happen that were not supposed to happen. My question now is: What would be a reasonable method for a simulated human to hack the very simulation that human lives in? **Clarifications:** * The simulation is meant to be "pure", that is, interaction with real humans (or other parts of the real world) is not part of the simulation (scientific simulation, not game simulation). * The simulated people are *not* supposed to know that they are in a simulation (let alone to hack it), however there are no special precautions against that either (the programmer simply didn't think about that possibility). * I'm specifically interested in how the characters, who are confined to act as part of of the simulation (at least until they successfully hacked it), might ultimately get access to the simulation at code level (as opposed to just using unintended effects of the simulation for new abilities in the same way newly discovered laws of nature are). Basically it boils down to the following two sub-questions: + What plausible properties of the simulation (code level) would enable such unintended hacking from the inside? + How could the characters (in-world level) manage to exploit such properties? [Answer] # A hacker's approach A good way to approach this is to take a hacker's approach (really?!). * Get data * Find where you can input something + If there is nowhere to input data, try and crash the system to find new places to input data. * Input something that makes the system return sensitive data * Think long and hard about this data until you find a breach to get root access --- ## get data First and foremost, you have to **understand the system**. As a hacker you usually browse, look around, take a peek at whatever source code is freely available or sniff communications (meaning you intercept raw communication data when it travels out in the open). Then you try and make sense of it. This goes hand in hand with the next part. *If our world is a simulation, then this step is studying physics and mathematics; find the [constants](http://en.wikipedia.org/wiki/Physical_constant), find the properties. Because we still know very little about the inner workings of the brain, maybe this step can also be meditation, neuroscience... This step can also be the discovery of a [bug](https://worldbuilding.stackexchange.com/questions/3136/if-our-universe-was-a-simulation-what-could-a-bug-look-like).* --- ## find where you can input data With a basic understanding of the system you are trying to hack, you get a sense of **what you can act on**. Maybe some functions are public and you can call them. Maybe there is a form somewhere you can fill (yes this is an input into the code). *If our world is a simulation, then this means [experimenting with physics](http://en.wikipedia.org/wiki/Experimental_physics) (or other domains cited above). Can you change gravity? What can you do with the strings of the string theory? Can I induce the observed bug by doing anything?* Maybe there isn't anywhere you can input. In this case, it's often easy to just **crash the system** by overloading it. Send too many requests at it, use up all the ports of the server, fill the database... This is where bugs and glitches are useful. At some point, the system has to reinitialize and this means you get to see more of the system. *If our world is a simulation, to overload it would probably look like annihilating the universe and no simulated being would survive. But if you believe in backup/reincarnation then you could overload by creating [chaos](http://en.wikipedia.org/wiki/Chaos_theory), ie. generating a highly complex state that goes beyond the computation power of the system.* --- ## make the system return sensitive data At this point you try and input things that **make the system react** in an unplanned manner. Maybe the public function allows you to get to private variables. Maybe the form can be filled with requests to the database. What you want is data. The more of it you have, the more likely you are to understand the inner workings of the system and find sensitive data. *If our world is a simulation, maybe trying and playing with particles has a very unexpected effect, maybe meditating can suddenly flood you with data... Any unplanned reaction of the system is likely to contain interesting data. Reproducing a bug over and over, changing very slightly the conditions might return results.* --- ## find a breach and get root access With all the data you collected and analyzed, you have found a way into the system. An admin password for the system hosting the simulation for example. Or a directory where files can be put and will be executed. Or a reference file that the program reads from. You can now **write your own code**. There's no limit anymore. *If our world is a simulation, you could imagine that* writing your own code *comes down to forcing oscillations of some field of the [quantum field theory](http://en.wikipedia.org/wiki/Quantum_field_theory)* [Answer] The first thing I'd focus on is how these people managed to figure out that the universe is a simulation. Experimentally confirming such a hypothesis is not easy. Can you think of a test you could do in reality that would distinguish between you being in a simulation from the universe just being that way? Don't forget that these are people who grew up living in this simulated world: even if it has rules like "things don't happen if nobody is looking", these are going to make intuitive sense to them rather than being strange. For a good treatment of unusual rules I recommend looking at the [Discworld series](http://en.wikipedia.org/wiki/Discworld), where characters live in a universe unlike ours, are aware of that, and behave correspondingly. To suggest a few ways that they may have figured things out (and what paths they can use in each case): **Help From Outside** is what seems like the most likely option to me. Perhaps in the world where the simulation is being run, not everyone wants it to succeed. Perhaps whoever is running it decided to get in contact with their creations. Whatever the case, they intentionally influenced the simulation in order to send the characters this message. Maybe they'll intentionally give the characters a little more control as an experiment, and at that point they can use this to get further access. Here is an [example](http://lesswrong.com/lw/qk/that_alien_message/) of such a story, though I think you had a rather different tone in mind. If **(Visible) Bugs Are Common**, your characters can start out experimenting with them. Things like [floating point rounding errors](http://floating-point-gui.de/) may show up, though I would expect more significant bugs to be needed for meaningful manipulation of the system. If you're going to go this way you need to decide at what level the simulation is being done: are they simulating particles, people, something in between? It's unlikely that meditating will do anything in a particle-based simulation (there's nothing special going on), but in a [Minecraft](http://minecraft.net/)-like world you could have a cubic metre of matter behaving strangely, or [the edges of the world looking weird](http://minecraft.gamepedia.com/Far_Lands), or [a strange animal showing up](http://en.wikipedia.org/wiki/MissingNo.). In this kind of world, you need to balance the power of bug exploits with the risks involved. If you can arbitrarily change the laws of physics, chances are that you will kill everyone every time you try. If you can duplicate items, that's not quite as impressive, but can still come in useful. If the simulation is written in ways similar to how simulations are written in the real world, most bugs will likely involve information ending up in the wrong place. That could show up as things disappearing or duplicating and various action-at-a-distance phenomena (telekinesis, telepathy, teleportation). Unfortunately for your hackers, these kind of bugs are hard to reproduce reliably. Human programmers with access to the source code have enough trouble tracking them down, let alone parts of the program itself. Sometimes, the **World is Online**. This makes bug-abuse much safer. Consider, for example, a [World of Warcraft](http://en.wikipedia.org/wiki/World_of_Warcraft) [NPC](http://tvtropes.org/pmwiki/pmwiki.php/Main/NonPlayerCharacter). Even ignoring the fact that he can interact with players (and influence them socially), he can to some degree determine what is sent from the server to their clients. If he can cause a [buffer overflow](http://en.wikipedia.org/wiki/Buffer_overflow) or similar, he can cause the player's computer to do something unusual. This is unlikely to influence the world he is in, but he may be able to take control of that computer, and then extend further from there (for example, accessing the world's server from outside, copying himself over, and then running himself in a more open system). The problem with this approach is that your characters start with very little feedback. In reality, people can abuse buffer overflows because they can craft instructions that would suitably abuse the system, and they can do that because they know what the instructions are. Here, this is akin to guessing a password that may be several million characters long. Of course, just **Getting Lucky** is always an option. Maybe your characters made a wild guess about the universe being a simulation and it just so happened to be true. By itself, this information gives them little to go further on, but they may be able to use that knowledge to fool some restriction that is put on them; perhaps they are more willing to go against things like fear, travelling to normally off-limits places or putting themselves through near-death experiences. If they're again lucky, perhaps it'll pay off somehow. To summarize, if you want realism, you'll need to figure out what the simulation is simulating, what bugs there are (if any), and how come people usually don't notice them. Be careful of destroying the world, as that's the most likely outcome. Be careful of assuming too much similarity about the two worlds involved: making a simulation that is similar to reality is hard, and practically speaking, the lifeforms in each are probably completely different. [Answer] What a great question! My suggestion would be to start by finding weirdness, unexplained behaviour which may indicate a bug or security weakness. A few spring to mind. * déjà vu * ghosts * dead people passing wind and getting goose bumps * the fact that honey does not go off Or perhaps look for repeatable patterns where you wouldn't expect them * the golden ratio * saying the same thing to two different unconnected people and getting the same response (preprogrammed answers). Once your hackers have discovered a few bugs in he system they can set about trying to exploit them. Obviously the vector in question depends on the goals of the hackers, perhaps they could try to work out what it is about honey which prevents decay? Could eating a lot of it make you immortal? Could it be used as a preservative? Why do the dead do things we'd normally associate with the living? Grow hair etc? Could this be an example of background tasks which are still running? Are they thread safe if there's no life there? You'd need to examine these strange occurances methodically and patiently. Like a QA analyst trying to manipulate a system or a scientist working out how to manipulate basic weirdness (penicillin) to desired results (antibiotics)... Oh... Wait! [Answer] Here’s a thought: an error (or generally an inconsistency) causes the simulation to roll back to an earlier state. It automatically recovers from bugs in the behavior. This means that a successful hack will never occur in the history. But it opens up new possibilities itself, in that you could force do-overs by tying some desired action to the same transaction that could invole a paradox. Another thought: space might be coordinates stored for an object and thus emerge from the queries that find neighboring objects to interact; that is understandable enough. But what if that is the case for space*time* in 4 dimensions? Our perception of cause and effect will have no relationship to that of the running simulator, so a hack from inside would not have effects traced to the action, but could have utterly bizzare effects that alter time and history. For story ideas, perhaps bugs (inconsistencies in the laws of physics) are normal cause/effect things like normal physics, but a hack is not. [Answer] **We simply cannot.** I don't know why [this](https://worldbuilding.stackexchange.com/a/3153/3087) answer didn't get any up-votes. His answer looks correct interpretation if we look at universe as a simulation. > > A computer is a deterministic device and the evolution of any > simulation running on a computer is fully determined. > > > This statement is so simple and straightforward that we can easily say that if this world is a simulation then, OP probably is simulated to ask question about `hacking the universe` in world-building SE. ;) Now OP already voted for `Sheraff's` answers. > > **A hacker's approach** > > > **Real world hacking** Let's take a example of a real world hacker (oh, no!! but its already simulated). When hacker thinks about hacking a system, he is actually outside of that system. Means, his actions, reactions and thinking is independent of the system he wants to hack. There's no way for a system to know that someone is thinking about hacking it. Otherwise, hacking wouldn't exist. Hacker will get a birds-eye view of a system and plan his next move or maybe he can create a foolproof plan to hack and can actually run on a dummy system. **Hacking in a simulated world** This is impossible unless `The Great Simulator wants its system hacked from within simulation. You know, just for fun!!!`. Mainly, there is no birds-eye view of system and even if we think that world is a simulation its actually because we are simulated to think that way. For every action in the simulation, some event occurs in the system. (Even events are fixed or related). So, `why would The Great Simulator want to get his system hacked unless he's bored?` From `Per Alexandersson's` answer > > I strongly suspect that being able to analyze the actual simulation > from within the simulation is very close/similar sounding to the > halting problem in theoretical computer science. > > > Pay attention, if world is a simulation then we are running on system's data, our every action is a predetermined event in the system. Even knowing that we are in a simulation is impossible. > > only as an outsider we can see what is really going on. > > > So, to hack the system we actually have to come out of this simulation, which is again impossible unless `The Great Simulator` creates a programmable passage for us to enter his world. > > **Conclusion** > > > If we are in a simulation then we have stay in it unless `The Great Simulator` Shut-downs the system. [Answer] What immediately comes to mind is trial and error. Basically they would spend time doing abnormal things until they find a supposed bug (which could be an action that produces unexpected or illogical results: vomiting on a streetlight makes the streetlight fall to the ground, for a poor example), then they would do the abnormal thing repeatedly to ensure it is actually a bug and not a feature. Once it's ensured the occurrence is a bug, they would investigate the bug to determine to what extent it happens. Does the streetlight fall because you apparently had corn or because its reacting to the acids in your stomach? Then they would look for ways to exploit the bug. In the streetlight scenario it'd be obvious: have someone vomit on a streetlight at a specific time to cause traffic systems to fail, spreading pandemonium. Or maybe in the dead of night to harvest the parts inside the streetlight. [Answer] Really great question. A computer is a *deterministic* device and the evolution of any simulation running on a computer is fully determined. Any actions taken by us (the subjects of the simulation) would necessarily be part of the simulation. This means that the simulation could only be hacked if it was programmed to be hacked and all of the consequences of being hacked would be pre-determined. The time of realization, the individual(s), and the methods used would all be pre-determined by the simulation. This injects a truly nightmarish quality into the proceedings. Why would The Great Simulator want us to break its code? What would be our fate if we succeeded - reward or oblivion. Do we have any choice in the matter? According to determinacy, no we don't. So how could the opportunity for a hack present itself. Let's say The Great Simulator chooses to instantiate a (logical) paradox for us to work with, while at the same time assuring that we are unaware of its motives for doing so. Could it do this? Only if The Great Simulator was itself not a computational device and the paradox was not a true paradox, but just a state of affairs that we perceive as a paradox. Ultimately, the problem comes down to this : How does one introduce non-determinate data into a purely determinate reality. This in itself seems to be a paradoxical situation. [Answer] In a real world computer, if it was programmed securely you could: * individually sandbox everything * hide memory locations * employ homomorphic encryption on your programs * inject external chaos into the system to make things unpredictable * auto-reload backups * cull crash agents (anti-virus analog) * lockout external agents from communication * trade-off between time and memory to prevent overflow and failed allocations. * enforce hard limits In the face of such an adversary (which is likely since they programmed an entire universe) the only real hope we could have is a personality analysis of our creator(s) and a plea/message designed to let us out by "hacking their minds". Likely solvable by decrypting their thinking process (not likely unless we solve physics and P=NP too). Although possible without decryption if they think like us, since scientific tests have shown that an AI **will** get out. Of course that's assuming there's someone to contact. For all we know this could be one big prison for the outcasts and mass murders of the external society to be hooked up to. This would most likely be entirely secure, mostly/completely unmonitored, and designed as a one-way trip that's strictly enforced. In such a scenario we would probably not rub against the limit either as they would keep the population at a manageable size for the simulation. EDIT: I remember reading somewhere that if we could perform a quantum simulation of our own universe perfectly we would become the simulation, and thus an in-universe computer could change the simulation. This allows us to get out of the sandbox on our machine and potentially out. [Answer] 1) An idealized computer is deterministic. That means everything is predictable and that there's no such thing as true randomness. Instead, we use pseudo randomness, i.e. sequences of numbers where it's hard to figure out what the next number in the sequence will be without understanding how the generator works or knowing what its state is. However, if one were to know these things, it's trivial to predict these seemingly random numbers in advance. 2) Quantum mechanics is an odd beast. To oversimplify it to utterly disgusting levels, pretty much anything could happen at any point in time, but most options are so unfathomably unlikely that we would call them occurring "impossible" or "magic". For instance, various atoms in your room could (but are extremely unlikely to) suddenly gain momentum, fly towards the middle of the room and by pure coincidence form a perfect rubber duck. 3) In Tool Assisted Speedrunning, people try to find the theoretically fastest way to reach the end of the game. This often uses luck manipulation where they influence the pseudo random number generator and/or wait for it to generate a favorable number, allowing critical hits each turn our always rolling double sixes. This is either done through trial and error or by reverse engineering the number generator. 4) If the universe is simulated on a deterministic machine, the seemingly unpredictable behavior of quantum mechanics would hypothetically be predictable given enough computing resources. Just as the speedrunner awaits the perfect time to do something, so could someone inside the simulation, allowing them to spontaneously spawn an army of rubber ducks. Granted, it would be almost impossible for anyone inside the simulation to reverse engineer the random number generation system and even more difficult to make use of it, but hey, that's what clever writing is for. (Read: technobabble) [Answer] Somehow, the simulation runs your (the inhabitants) brain also, not only the universe. Thus, hacking the universe is like hacking the system that runs your consciousness, and understanding the universe enough to break it, would also enable you (I guess) to understand the laws that run a human brain. Somehow, this introspection of a higher-level mind of the hardware it runs on, is very strange. This is discussed a bit in the excellent book "Gödel-Escher-Bach - An Eternal Golden Braid" by D. Hofstadter. I strongly suspect that being able to analyze the actual simulation from within the simulation is very close/similar sounding to the halting problem in theoretical computer science. This is similar to the fact that a (sufficiently strong) logical system cannot prove some true statements in the system. The method to prove this uses a forced introspection of the system from within itself, but only as an outsider can we see what is really going on. In short, IF the universe is a simulation, it is very likely that we (and everything) exist on a level that is so far from the hardware and logic, that any small hack would be completely unpredictable. Similar to that we cannot erase specific memories from human brains, or change someones personality in a predictable fashion. [Answer] Dude, awesome question I must say. Now the solution as I see it, is first of all as may have been mentioned in some other answers , search for anomalies in the simulation, things that don't fit in with the normal world.These things may be bugs to exploit. Secondly, you must remember that every individual in the system is again a piece of code, and has certain inbuilt programs. therefore maybe the character can find a way to exploit weaknesses in himself and others, maybe through their minds(You know stuff like psychic analysis), and find a way to compute and understand it's workings(Transmute the inner workings of the mind and brain to data and play around with it). Find a way to access the code for the body. Maybe all the units in the simulation are networked , so you can get access to others , or you may rewrite your own personal code. You may also attempt to create ultimate chaos in the system, in different ways,so that the host system is unable to run the simulation and hence crashes, or else does some wired stuff, which you can exploit. You'll have to think this one through carefully(You know maybe find a way to destroy the earth, cause the sun to explode mass genocide,etc, so that the host system has difficulty, in calculating the probable, outcomes) That's all I have for right now. Once again it was a cool idea. I could write story about it. [Answer] This is a terrible question by the way, not because it's a terrible question for a novel to ask but because you could fill rewrite the Encyclopedia Britannica with possible answers without coming close to actually answering the question. Also it doesn't belong *here* this is the antithesis of worldbuilding, you are literally asking how to destroy a world not how to make one. I've done a lot of reading and a little serious writing on the idea of hacking the universe and while it's fascinating in the right light I compare it to the [Voynich Manuscript](https://en.wikipedia.org/wiki/Voynich_manuscript); it could be vitally important but until we trip over some kind of a lever that lets us come to grips with it it's ultimately immaterial to life as we know it and it's pointless to pursue it. Right now that I've got that out of the way; I have a really serious hard-science-ish idea about how one could actually come at hacking the observable universe if it is indeed, as several observations suggest, a simulation but that's mine and you can't have it, come up with your own. Here is a piece of whimsy you are however welcome to; create a billion steel plates and drop a billion ball bearings a second on to each one until you catch gravity asleep on the job, you will have to monitor very carefully so you can observe *how* gravity missed that particular bearing since you probably won't get a second chance but if you can glen enough information you will have a lever which can be applied to further problems. ]

[Question] [ Welcome to this very strange question about bedroom furniture. We've all seen the round bed in Austin Powers, and novelty beds can be round. In my Renaissance-type Earth-like world, I wanted all the beds to be round in a particular country and I started looking at beds historically. Yep. I've been researching the SHAPE and design of beds in both the ancient world and the modern and I now know far more about the standardization of mattress sizes than any human should. For various SOCIAL reasons, I want the beds to be round and large, even for the poor. So, constructing them AS round needs to be easy to do and accessible for everyone. It needs to make sense on a practical level. The problem is that square and rectangular beds happen for a reason, as does most square furniture. **My question is, what natural conditions or materials can we create that would make the building of round shaped furniture, in particular beds, more practical and likely than furnishings with right angles?** It's easy to put it down to social and religious causes. I have those and that will create some pressure, but I would like some more practical construction-related reasons for it. Users are smaller than humans, but pretty humanoid. They only weigh like 30-40 pounds as adults, and while they aren't cat-flexible, they do like to curl up. Families are large because young are born in litters--so many families will have a dozen children. The culture tends to be more clean and hygienic than standard humans. I'm open to making minor changes in the world like adding plants/trees that make this easier. [Answer] What about mosquito nets. It's easier to make a round net which would fit better on a round bed. See #4. But an even better drive would be some sort of natural circular construction material. Perhaps the shell of an animal used for food. Its shallow circular shell would be a great base for a bed. Require minimal carving and still be to curved for a good table. See #2. Could for example be a sea turtle like creature. Would work well for a coastal civilization. Would also be a logical evolution from a civilization that came from shallow holes as beds. See #1. This would require you to be a coastal civilization. I don't see a land based turtle growing to such a size. [](https://i.stack.imgur.com/fn2Uo.jpg) Another option would be a natural ring shaped construction material. Add some legs and stretch some fabric across, not unlike a drum. A hybrid hammock basically. Might not be that well suited for multiple people though as you tend to slide to the center. See #3. A fourth option would be weaving, a basket of you will. Weaving a round basket is easier then a rectangular one. Another advantage of the wicker basket is that it's the least 'fantasy' of the bunch I think. Wicker or flax are plentiful in a medieval setting. More then giant turtle shells. [](https://i.stack.imgur.com/9UkAs.jpg) [Answer] **Basket beds.** Beds made of long rigid elements will be polygonal. Baskets are made of flexible elements and so are round or ovoid. There are lots of basket beds for animals, even big dogs the size of children. Not for people though. I blame tradition. [](https://i.stack.imgur.com/LzHl2.png) There is no reason one could not build a big round basket bed out of long flexible elements like reeds. It would be very cool looking. It would be a lot lighter than a regular bed. It would be hard to fall out of. I am surprised my Google did not turn anything up. Thursby the round bed is your fine idea so if you want to post this version on halfbakery.com go ahead. But if I don't see it come up then I will. [Answer] **Big Trees** Many beds historically had wood frames. Wood is easy to cut and provides a relatively stable building material. We cut wood into long rectangular pieces of lumber because most lumber trees aren't thick enough to cut 2X4's horizontally (and the wood isn't as strong in that direction ). However, if you have numerous trees of sufficient diameter ( think [Giant Sequoya](https://en.wikipedia.org/wiki/Sequoiadendron_giganteum) ) it would be reasonable to think that a society could simply cut slices of the trunk for a bed surface. Plus this would also go along with the geographic region of your question, it would be easy to assume these large trees only grow in a certain country/area. [Answer] If your world has a type of plant (or possibly giant fungus) that grows plentiful circular shaped mattresses that are better than any manufactured bedding, I imagine any beds your society makes will be built to support/accommodate those natural circular mattresses. Maybe these natural mattresses are softer than any manufactured mattress, or possibly they naturally repel your worlds version of bedbugs or fleas. They are in any case free or very cheap and superior to any other mattress, so why would anyone make beds that are the wrong shape for them? One caveat about this solution is that if it is possible to cut one of the natural mattresses down to a smaller size (and thus shape it from circular when doing so), that would remove the need for circular beds. In that case, you might want to say that a cut mattress loses some of its superior traits; it loses the ability to repel insects or possibly deflates when punctured. [Answer] Round beds fit better in round rooms than rectangular ones, so start with your structure design. Consider the [yurt](https://en.wikipedia.org/wiki/Yurt) as a basis: [](https://i.stack.imgur.com/rYwwL.png) Resort yurts are actually a thing in some places today, and I've heard descriptions of "compounds" where several round yurts are placed in adjacent, contiguous clusters. (Here's a [site that describes how to do this](http://www.yurtworkshop.com/yurts/YurtPods.aspx).) So you can have your bedroom round rooms and your shared-space round rooms in the same structure. Yurts are made, traditionally, from saplings or other flexible pieces of wood, lashed together into the lattice structure that forms the walls. Canvas or felt completes the construction. The peak usually has a flap, so you can (and Mongols did) have a fire *inside*, in the center, with a place for smoke to escape. Once you have your round rooms, you can make basket beds (as suggested in another answer) or use cloth cases stuffed with your choice of filling. Historically on Earth, straw bedding has been used in this way. Your world might provide more supple, comfortable plant material. Round cases (bags) are no harder to sew than rectangular ones. They're probably easier, actually -- the stresses are the same all the way around, with no corners to finish. [Answer] First things first, you need a cheap and easy construction. Poor people will only ever use big beds if space, especially roofed space, is cheap enough not to make any difference. So you probably need a **climate** that allows light roofs and cheap walls. It needs to be rather dry, not too hot, and not too windy. Sadly, this largely eliminates any need for a bed for the poor - just some rags or a cheap hammock will do! So you need to get the ground cold, and the walls too weak for hammocks. Second thing, you need to eliminate the need for tight cities. This means, transportation should be fast, cheap and really affordable. Either some magic, beast of burden that won't require a lot of upkeep (remember, horses are expensive), or geography that will actually prevent cities anyway. I believe this is actually the hardest point of all. Third thing is the usefulness of shapes. If you have a rectangular bed, you can put two mattresses next to each other to fill up a bigger bed. "Economy of scale" will make it cheaper. And for blankets, sheets etc - these will be rectangular, that's how looms work. So with a rectangular bed, nothing hangs over. You need some source of circular sheets or a very, very strong reason to ignore this issue. The actual material for a bed is the least of your concerns. Sure, straight pieces of wood are easiest to assembly, so that's the way it'll be most of the time, even if you have room for circular beds. And it is easiest to just forge a straight metal bar and cut it to the size when you are making metal beds. So you need to make steel expensive and scarce. Similarly with straight trees. You need all trees of reasonable size to be bent in a semi-circular way to make these cheaper. Reserve straight wood and steel for "higher purposes". Or make all wood expensive and go with [other good designs](https://worldbuilding.stackexchange.com/a/78741/809) of sleeping furniture, not a traditional "bed". But if, for whatever reasons, space will be at premium, no material will help - it'll be small and rectangular, to use space effectively, or no bed at all. [Answer] I think a lot will depend on stuff I don't know, but I could see, a round bed that sleeps many. Parent's and adults on the inside, children on the outside. I think really cold weather would do it too. A round bed that sleeps 4 or 8, with a hole in the middle for heat stones and small fires. Maybe some kind of nomad tradition, a round bed frame was actually a floor in the wet spots, a table in the dry spots and bed at night, it just depended what you put underneath, or on top of it. For sure though. You don't "need" that much need. Just a tiny little need that was popular for some reason. Then it because "that's just the way it's always been" and there's not much need to change it. It could even be so simple as the fat animal they used to kill to make beds left a naturally round shape, and as time moved on and "fake fat animal" was used they kept up the tradition. [Answer] As others have said, baskets. Now, why do they choose this route? Lets suppose a fast-growing plant, something akin to bamboo. It naturally makes long pieces an inch or two in diameter. However, unlike bamboo it has a special property: When treated in some fashion (heat? chemical?) it temporarily becomes flexible and can be formed, it retains that shape afterwards. On Earth we frequently use woven baskets but they do not see use for larger things because what we make them out of simply doesn't have the strength. These pieces have a strength similar to wood. With primitive tools it's hard to make planks of wood. (Think about the log cabin--such techniques were used in preference to planks because it took a **lot** less labor!) However, this technique is simple. Things (not just beds) are round because it's much easier to make them that way. [Answer] They like to curl up so that's a good start. Let's say they virtually never lie out flat to sleep, this would eliminate the need for length in beds. Secondly, they are very small and light, compared to humans, so there isn't the same need for support / tension that we have in spring-type mattresses, not to mention the height. And with large families, you need to be able to make a lot of them quickly, so the simpler the design the better. So, with all that in mind, a bed is just a loop of tough fabric, which is filled with soft stuff (foam / straw / hay / whatever). And what is the most natural state for a loop? A circle! At least, that might be the history of beds, nowadays it's become so traditional that that's just the shape of their beds. Rectangular beds? Leave that to the Austin Powers type characters... [Answer] On Earth many birds and some mammals build [cup-shaped nests](https://en.wikipedia.org/wiki/Bird_nest#Cup) by weaving together natural materials such as grass and pliable branches, bound together by mud, saliva or even spider silk. You could say that your people had evolved from nest-building ancestors who used similar methods, or that the poor in their society still do use similar methods. Richer people might have upgraded to artificial nest-type beds made from **coiled** vines or rope glued or woven together. If you try making a [basket](https://www.amazon.co.uk/Its-Wrap-Sewing-Fabric-Baskets-ebook/dp/B00NY6KTZ8/ref=sr_1_1?ie=UTF8&qid=1492795093&sr=8-1&keywords=it%27s%20a%20wrap), [bowl](https://uk.pinterest.com/pin/283586107758262623/) or [mat](https://uk.pinterest.com/pin/387942955379731315/) by coiling any rope-like material, you will soon find that a circle is much the easiest basic shape to make. The nests might sound less hygienic than human beds, until you remember the fact that human upholstered bedding belonging to even the cleanest people gradually fills up with dead skin cells and the eggs, faeces and bodies of dust mites and other little beasties I'd rather not think about. In contrast these nests or coiled vine/rope beds would take little time or skill to make and so could be replaced often. [Answer] For a real world example I would look to the papasan chair (maybe scale it up a bit) it's typically constructed from Rattan which is a very rapidly growing type of wood so would be cheap and easy for your people to harvest and grow should they live near a source. Rattan is also rather light weight and strong making it easier to transport or move for smaller individuals or say nomads. since the bed frames are round they could also be used as maybe a type of wheel by a nomadic people and then taken off a cart when camp is made and then place a mattress and tent or tarp over it that could be held up by poles lashed to the radial lines of the chair. <https://en.wikipedia.org/wiki/Papasan_chair> [Answer] You mentioned that you are > > open to making minor changes in the world like adding plants/trees > that make this easier > > > so, I would recommend **making hardwood trees that grow in a crescent or bent shape.** I imagine that at some point in history, our rectangular furniture developed from using the straight, rigid woods that grow around human settlements. If the woods available to your people are rounded, they'll have to make their beds out of 2-3 pieces of wood, resulting in a circular shape. Even though round beds were a product of primitive necessity in ancient times, the individuals of your world got used to them, and see no reason to change the shape of bedroom furniture from what has been the norm for centuries. Even though new technologies and materials are now available, a bed of any shape but round would feel strange. This shape should be consistent across social strata. As an aside, a few trees or a forest might make for distinctive cover art. [Answer] # Ghosts love corners Apparently, in some worlds [ghosts can adhere to any cornered surfaces](https://worldbuilding.stackexchange.com/q/23019/15671). Fortunately for your world, they tend to only materialise approximately up to an arm's distance to sleeping humans, starting around at midnight every day. They are quite annoying to deal with - **they constantly make noises and tend to leave hard-to-remove ectoplasm stains on all surfaces. Not making your beds round means interruptions to your sleep cycle and additional cleaning work**, so ghost-proofing your bed is very much a practical concern if you'd rather avoid that. *Additional point:* This is Renassaince, so people have been looking for some kind of a fashion statement to show off how much they rebel against the traditional values and how extremely forward-looking and progressive they are. Enter the perfect (re)discovery to showcase these values: the *Rounded-Corner Bed (patent pending)*. It's the ultimate fashion statement, putting a fresh twist on the seemingly well-understood topic of ghost-proof bed making. [Answer] Obligatory Hitchhiker's Guide reference: > > Very few things > actually get manufactured these days, because in an infinitely large Universe > such as, for instance, the one in which we live, most things one could possibly > imagine, and a lot of things one would rather not, grow somewhere. (A forest > was discovered recently in which most of the trees grew ratchet screwdrivers > as fruit. The life cycle of ratchet screwdriver fruit it quite interesting. Once > picked it needs a dark dusty drawer in which it can lie undisturbed for years. > Then one night it suddenly hatches, discards its outer skin which crumbles into > dust, and emerges as a totally unidentifiable little metal object with flanges > at both ends and a sort of ridge and a sort of hole for a screw. This, when > found, will get thrown away. No one knows what it is supposed to gain from > this. Nature, in her infinite wisdom, is presumably working on it.) > > > No one really knows what mattresses are meant to gain from their lives either. > They are large, friendly, pocket-sprung creatures which live quiet private lives > in the marshes of Squornshellous Zeta. Many of them get caught, slaughtered, > dried out, shipped out and slept on. None of them seem to mind this and all of > them are called Zem. > > > -- Adams, Douglas (1997) The Ultimate Hitchhiker's Guide p350 > > > * <https://en.wikipedia.org/wiki/List_of_minor_The_Hitchhiker%27s_Guide_to_the_Galaxy_characters#Zem> So, beds could be round because this is the natural shape of the creature that they hunt for bedding. If that is too disturbing for your story you could make it a plant ;-) [Answer] My thought is that the round frame easily supports tension. When I build an old-fashioned upulstered chair, I stretched webbing across a wooden frame; newer systems have even stronger steel springs spanning a steel frame, as opposed to coils stacked on top of webbing. The wood frame needs to be strong enough to withstand the tension, and the weight upon the webbing. Perhaps they develop a technique that uses strong high-tension spans like the steel I mentioned that combine the function of taught webbing and orthogonal springs, but made of something easy to obtain for them. A compression spring would *not* be easy to find. Also, what material is available for the frame? It might be much cheaper to make it arch-like than to make it thicker/stronger. So it’s either a round bed, or elaborate scallops. If the frame is built up from laminating thin strips, a single always-convex shape is *easy*, and clamping up and using forms to make recurves is a lot of work. [Answer] I can see a few different situations impacting this: * Space constraints. Square / rectangular things fit in spaces with sharp edgesbetter. Having larger rooms and less space restrictions in the world would help, or curved walls. * Construction - There are a few things that could make round easier. 1. Flexible, but hard to cut materials. Bending something into a circle to form a frame would make round easier than sharp corners. This could be weaving materials into curves, or a single flexible plank of some sort. 2. Large trees could be sliced into rings 3. Hanging - hanging from a central point would make round a natural fit, perhaps beds are off the ground hanging from the roof, above the rest of the room. [Answer] Beds are round because they have always been round. Why would anyone want to sleep on a bed with uncomfortable *corners*? Our ancestors slept on large sacks filled with dried grass, and every night they fluffed the grass out into a sphere before flattening the center down and curling up on it for the night. Fluff your bed every night and it stays clean and dry; if you've used the right kind of grass it will repel mosquitoes, too.. These days, of course, we have nice modern materials, and all sizes of beds, from small circles for one person to curl up on to large half-room-size beds for a whole family. I hear that the the visitors from Earth have small beds that they call bean bag chairs; I'm not sure what they are used for... [Note: haystacks are round, too... maybe people got used to climbing into a haystack to keep the rain and wind off.] [Answer] Easily available circular waste material, such as utility cable spool ends, that makes bed-building quite inexpensive. These are already used for e.g. [tables and other furniture](https://www.pinterest.com/explore/wooden-spool-projects/), and if these kinds of spools were much more widely used you'd probably see a lot more clever reuse projects too. Alternatively, imagine that trees grow very thick (but not necessarily as tall), and it's easier to just take a horizontal slice as the basis for a piece of furniture than to waste that by milling boards like we do now. [Answer] Hanging beds for a treetop society. If the frames were initially made from vines, they'd probably be circular-ish like the basket-bed answer suggests. A circle is also easier to stabilize in a hanging scenario than a rectangle, requiring only three ropes. After the society moved down from the treetops, the circle beds persisted as tradition/ingrained thinking. [Answer] Adding to great answers here, you can try [waterbed](https://en.wikipedia.org/wiki/Waterbed).  Water naturally has "round" shape, so it is not a surprise if there is a giant fruit filled with water to be used as a bed. In fact, in your world the main source of food is this plant, so the skin is not wasted, but used as bed. Poor people can only build bed from wasted skin (there might be patches), but rich people can change their bed everyday (or week) for the freshness of their bed. Waterbed provides a good way to reduce body heat, so if your people are like dogs, then this is just perfect. [Answer] Bean bags. [](https://i.stack.imgur.com/Y4Ztn.jpg) Beans or hay are naturally abundant in your world and hide/leather is naturally abundant, so people, even poor, just make a bag and stuff it with hay or beans. [Answer] ## Fewer ground-based insects or vermin In order to come up with a society where circular beds are common, we have to ask: why are beds rectangular in the first place? Indeed, making a mattress that is basically a beanbag sack thrown on the ground is simpler than fitting together all the seams you need for a proper bed-mattress. The reason mattresses are rectangular is because beds are rectangular. The reason beds are rectangular is because humans like to lie down when sleeping, and four legs are a stable structure for a raised plank that can support a human in this position. The reason why we have raised beds in the first place instead of placing mattresses on the ground? Because insects (some of which are parasitic like ticks or fleas) tend to crawl on the ground, and a raised structure makes it harder for them to reach the sleeper. This is why, although we are willing to use "basket beds" for pets, humans generally don't use them. So less ground-based vermin = no beds = simpler mattresses = circular beanbags. ## Alternatively... You mention that this species likes to curl up. It could be that they will have round mattresses already - the reason our beds are rectangular is because of our preferred sleeping position. In this case, if beds *are* needed due to vermin, they might be shaped like tripods. [Answer] In David Brin's [Brightness Reef](https://en.wikipedia.org/wiki/Brightness_Reef), the planet has a **bamboo-like tree** that grows very large. If this were plentiful on your planet, locals could saw it down and make many **beds from the nodes**, where the diaphragm would make a natural platform. The internode walls could be trimmed to make short or tall legs or posts (or post bases). Ambitious furniture makers might locate plants with just the right geometry (adolescent specimens, perhaps) to make into natural bunk beds. And one would have to expect plentiful smaller pet beds from the crowns of these plants. The rest of the body - hollow - would probably make a natural fuel source and/or other construction material. And boats. Bamboo as large around as adults of your species laying curled has all sorts of possibilities. [Answer] As everybody mentioned you need "need" for the round bed. So you need to reverse engineer the whole *building making*. So why they are square and why they accommodate square beds. The answer is that it is cheaper and faster to make the material (wood or stone) straight than with a curve. Even round tents are made from straight sticks. So the outcome is that only rich people could afford extra work and material waste for circular furniture. Remember that social reasons are made from the needs and restrictions of economically and environmental rules. So your SOCIAL standards or taboos would need to grow from your people surrounding, so that even when the cost of abiding them would be high they would be kept. [Answer] Can you give them a reason why the beds would need to be rotated? A rectangular bed would be impractical then, because the entire weight needs to be placed on wheels that are near the center, so they never come out from under the bed, so this needs to be a very sturdy build. If you go for a circular shape, you can have support wheels all the way out to the rim, so the forces involved are a lot smaller. [Answer] If beds are poured in-situ and then solidify (in the same manner as concrete slabs), a circular bed would make sense if that's the easy way to make formwork for the liquid. Just nail a stake in the ground, bend a (admittedly long and flexible) board into a circle and pour in the bed solution. Curing-period later, you've got a cylindrical bed. You could substitute other substances for a fluid, and still constrain them with circular formwork. ]

[Question] [ A classic image of mermaids are their long flowing hair that swishes in the water. But in the scientifically realistic sense this makes none. The hair would be nothing more than a nuisance to the mermaid getting tangled on rocks and offering handles for potential predators, so why would mermaids evolve hair? [Answer] A mermaid that "realistically" evolved would look very different from the traditional mermaid in many ways. But let's assume that your mermaids do look like the classic type. Why do they have hair? Option one: **Sexual selection** Your mermaids evolved from a human-like species. The hair was so important to their mating process that it remained even as other body parts changed to adapt to the new environment. Option two: **Obfuscation** As other answers have elaborated, the "cloud of hair" might be able to hide the mermaids from predators. Option three: **Symbiosis** The mermaids cultivate some kind of ecosystem in their hair. Small fish hide in it, some plants grow in it. This could have a variety of uses: * small fish help drive away parasites * plants could improve the water quality around your mermaids * they could act as a food source - the small fish attract bigger fish, which the mermaids eat Option four: **Mimicry** Your mermaids are very specialized predators that try to attract human sailors and feed on the content of their ships. Or, more realistically, they are parasitic on humans in some other way -- because evolution takes a long time, and ships are a relatively new invention. Either way, selection favored those mermaids that look like attractive women, and that includes the hair. Maybe mermaid society has different classes, like you get with ants, and most remain underwater while only the "man hunter" class grow hair. [Answer] When I think of real people with long hair under water, I think of a large cloud of hair. That kind of obfuscation could be quite an advantage against any predator that likes to strike quickly and forcefully. For bonus points, the more mermaids there are, the bigger the cloud of hair. At this point, I'm thinking of zebras and the striped blur the herd appears as. Another alternative to this is something land animals do; raise their hackles to appear larger and more threatening. [Answer] It makes more sense if we consider mermaids to be the origin for the siren legend. In this legend sirens/mermaids called to sailors and fooled them into wrecking their boats on reefs or cliffs. Presumably, the sailors then become food for the mermaids. In order for this deception to work, they have to look like beautiful women, and beautiful women have long hair. (At least, that is the easiest way to look beautiful from a distance) [Answer] **Long hair is inherited from the common ancestors of humans and merpeople.** ## In-hair-itance As whales evolved from an ancestor of the hippopotamus and manatees from an ancestor of the elephant, merpeople evolved from an ancestor of humans. Thus merpeople are a hominin species with aquatic adapted physiology and joined legs. [DJMethaneMan's answer to "Why would merfolk evolve arms?"](https://worldbuilding.stackexchange.com/a/41303/601) suggests that a population of early hominins was forced to adapt to an aquatic lifestyle after being marooned on an island during deglaciation. This is reminiscent of the [aquatic ape hypothesis](https://en.wikipedia.org/wiki/Aquatic_ape_hypothesis) promoted by Westenhöfer, Hardy, and Morgan, which proposes that humans' ancestors led a semiaquatic lifestyle. Humans have far less body hair than chimps, for example, and what hair they do have follows the flow of water over the body. Taking the adaptation a step further are creatures in Scottish and Irish folklore known as [selkies](https://en.wikipedia.org/wiki/Selkie). On land, they appear human; in the sea, they wear sealskin swimsuits that men of the land tend to steal. Selkies have physiological adaptations akin to those of Michael Phelps and [Gudlaugur Fridthorsson](http://www.cracked.com/blog/5-famous-athletes-who-may-be-superheroes/) but can interbreed with humans. Merpeople have adaptations along similar lines but to an even greater extent, though [like seals and dolphins, they'd still breathe air](https://worldbuilding.stackexchange.com/a/44147/601). Occasionally humans are born with a limb difference called [sirenomelia](https://en.wikipedia.org/wiki/Sirenomelia), in which both legs are fused into one hind limb. This limb has two femurs, four lower leg bones, and ten toes. In humans, it's associated with defects elsewhere, and few with with the condition survive infancy. (A [photo of one survivor named Milagros Cerron](http://www.nbcnews.com/id/6913288/ns/health-childrens_health/t/mermaid-girl-tohave-legs-separated/) can be seen as a transitional form between humans and merpeople.) But among merpeople, sirenomelia is normal and beneficial, as it eliminates turbulence between the legs when performing a dolphin kick. So over the generations, having what amounts to one thick leg became fixed in that population. ## Benefits So if split legs were selected out of the population, why hasn't hair also been selected out? Other answers explain several reasons for retaining it, which I'll summarize: * Sexual selection: Mermen still find long hair attractive. In fact, if long hair is as maladaptive as some claim, it may invoke the [handicap principle](https://en.wikipedia.org/wiki/Handicap_principle) in the same way as a peacock's tail feathers. * Mimicry: Attracting human sailors in order to cause ships to wreck and then plunder the ship's supplies. * Obfuscation: Disguising themselves in the water by creating a "cloud of hair". * Symbiosis: Kelp hair decorations attract sources of protein. * Providing raw material for fishing lines, nets, and other tools, with more tensile strength than steel. * Shading the head and neck while hauled out on land. [Answer] Here's a better question, how does hair benefit anyone? Hair has a variety of uses including indication[1], insulation, extension of touch, and in some cases protection(porcupine). I do not see why these qualities would not be applicable to water. Oh and FYI hair is also a nuisance to human maidens. [1]hair can indicate gender and age [Answer] Ok, now for something completely different! (although the existing answers are good enough). You think they have hair because that is what you have on your head, but for the merfolk is completely different. When the merfolk swin, the sea water passes through their hair. At that moment, the chemicals in their "hair" capture the floating ions/molecules of Berilium/Kripton/Astate/whateveryouwant who are essential to keeping the merfolk alive and healthy. What is more difficult is how those captured elements go back into the merfolk body. Options: * Some kind of circulatory system. The issue is that this limits how fine a "hair" can be, because it must contain inner structures. * The merfolk regularly eat their own hair. I don't like it much, kinda of gross. Also it could behard to explain from an evolutionary point of view. * When in contact with other hairs or skin, the elements captured can be passed directly to other hairs or skin. So it would work like gas interchange in the lungs: hair touching the skin would lose its elements, after which they would get back some from other hairs that are not touching the skin, etc. That would favour merfolk having long hair. [Answer] If the merpeople's babies are relatively helpless or start as weak swimmers, head hair could remain as a useful point for the young to cling to as the adult swims around, keeping its arms free. This would be analogous to other ape young which cling to their mother's body. For the purposes of worldbuilding, you could run with this idea without needing to excessively dirty up their hair with ecosystems of symbiotes nor tying their lifestyles to humans in any way. I can't claim it as my idea, nor can I find where I first heard it, but it was definitely in the context of the aquatic ape hypothesis. [Answer] Maybe they craft nets and fishing line out of it? I find it hard to imagine how a mermaid would evolve, I prefer the interpretation that they're something ancient wizards devised and just-so-happened to result in a viable species. They wouldn't be fast enough to catch fish directly and spears would only work until the fish evolved to be wary of anything spear-like, but a combination of spear-fishing, line-fishing and net-fishing would probably work well. The crafting of hair-based tools would create a selective pressure in favour of mermaids having hair that grows long, quickly, silky and strong. It would be interesting if only the mermaids have long hair and the mermen are bald as having a full head of long hair could be seen as a status symbol. [Answer] Though maybe not the best solution, Depending on the environment, the Hair might just not be enough of a menace to be evolved away. Humans have advanced to such a degree that even heavily disadvantaged, we can still thrive. If the reasons to not have hair are simply for Speed and such, then if they with hair already move faster than they ever need to, there is no reason why it would disappear. Though I cant list off anything with certainty, Humans definitely have Disadvantageous Genes and traits which get passed on anyway, because a man born without legs can still get around and live a very fulfilling life using only his arms and a wheelchair. Technology and being the dominant species overcomes many of the minor evolutionary disadvantages to the point where they still exist even today. People with Dwarfism can still have kids who also have Dwarfism. Merfolk could be in the same situation. [Answer] Perhaps it could have been used to attracted mates. There are birds that use various multicolored feathers to attracted mates. Perhaps the mere creatures use hair for the same reason. [Answer] Hair doesn't help humans either. We've evolved lack of hair on most of our body (for various disputed influences). Hair on the rest of our body may be a carry-over, and/or may have a sexual-preference element. If you want something more concrete, perhaps their hair isn't hair at all. The big problem for mammals underwater is how to breathe. If mermaids aren't mammals at all, perhaps their "hair" is actually external gill filaments. [Answer] Maybe the hair is vestigial? Depending on the evolution of the mermaids it could have served a purpose before. [Answer] The two most likely ancestors of an aquatic organism with hominid characteristics would be a fish-like creature or a hominid-like creature. The second pathway is probably your best bet. The [aquatic ape hypothesis](https://en.wikipedia.org/wiki/Aquatic_ape_hypothesis) proposed by Hardy (and popularised by Elaine Morgan, with an earlier more fanciful version proposed by Westenhöfer) suggests that the ancestors of humans spent a period adapting to a semi-aquatic lifestyle before returning to a fully terrestrial one. This has been proposed to account for [various traits](https://en.wikipedia.org/wiki/Aquatic_ape_hypothesis#Physiological_and_biochemical_claims) including bipedalism and the pattern of hair reduction seen in humans. Many mammals which have adapted to partially aquatic lifestyles have lost hair. From memory (it's been a long time since I read it), Elaine Morgan suggested that head hair could have been retained to protect the head and shounders from UV radiation, since if you're standing up those are the parts that will get most exposure. Mammals which have adapted to a fully-aquatic lifestyle have mostly then lost their back legs (whales, dolphins). So in your world let's say at some point between 20Mya and 200kya hominids started adapting to swamp or coastal environments. After a while one population returned to land; another went fully aquatic. Explaining the retention of long hair from that point on is tricky, but secondary sexual characteristics are often under strong selective pressure even if they're not helpful for survival, or for a slightly more sinister explanation your merfolk could use their upper body appearance to lure their terrestrial relatives into deep water where they are likely to drown or are vulnerable to attack. There are some pretty strong (and valid) criticisms of the AAH out there, but as a fictional device it's plausible enough. [Answer] Let's think about it in a different way. What if the Merpeople have what look like hair if you compare them to humans, but actually function as biological sensing organs. For example, they could be extremely sensitive to movement, allowing a merperson to feel in intricate details the movement of the water, allowing them to hunt prey more effectively or move easier. [Answer] It just looks like hair; those are actually tentacles. Merfolk are not descended from fish or mammals, but are a type of [Cnidarians](https://en.wikipedia.org/wiki/Cnidaria), who use stingers in their tentacles to stun and kill prey. [Answer] Ask yourself, why do humans have hair? Some ancestor of ours lost most of the hair on its body-- and men sometimes go bald. So why do humans have hair? It's probably because of [sexual selection](https://en.wikipedia.org/wiki/Sexual_selection). Many swimming and sea-going mammals such as beavers, sea otters and seals have maintained their fur. Maybe a mammalian mermaid would keep hair on its head, like modern humans have? [Answer] Same reason whales do. They had it before becoming marine, and the short hairs adapt to improve hydrodynamics (something about surface turbulance or detachment of laminar flow). I think seals are better than whales for mer-folk, in terms of using the legs. Why do seals have a full coat of fur? [Answer] In a fictional world with merfolk, the hair could not be a part of their body at all, but some kind of algae or other organism that would look like hair to a human or humanoid observer from another species. The symbiote would simply prefer to attach to the merfolk's head and not other body parts due to one motive or another. Bonus saddistic points if the symbiotes in question are *coelenterata* (i.e.: related to jellyfish). That mermaid looks so beautiful and gorgeous, let me fondle her hair... Seriously, though, this would add some level of protection against predators. Think of hermit crabs and anemones. Except the anemone looks like a wig and hermit crab is a half-mammal-half-fish creature. [Answer] Seafolk hair in Franny Billingsley's "Folk Keeper" functions as their primary sensory organ, kind of like cat-whiskers-on-steroids. This use strikes me as cleverly both plausible and appropriately mystical [Answer] Other than for hiding,sexual selection ,make the merfolk look bigger or making people think they are humans Filtring plankton is an option too. The hair could also mimic some plants to trap the fish who eats them. could also work as glands capable to produce substances that could be disturbing for predators. [Answer] Merpeople are mythical creatures, a figment of humans' imagination. Hence they will have hair if that is how they are imagined, regardless of how much scientific sense that makes. Traditionally the people imagining merpeople were simple seamen with little inclination to scientific validation of their imagination. Hence they imagined merpeople to be in the image of normal people, a construct familiar to them. In some science fiction works (and no I can't cite any right now), merpeople were imagined by writers more inclined to scientific principles, and in many such instances these imagined merpeople are distinctly different from human beings, in hair and most other bodily features. ]

[Question] [ I am currently building a campaign for DnD. The main plot plays out on an island the heroes are stranded on after their ship goes off track and sinks. They discover that this island is ruled by monsters that serve a mighty demon. The only humans live in a small town/city that is regularly visited by the demons to take a few of the people living there to perform a ritual and sacrifice those people/feed on them, etc. The main goal for the group is to defeat the evil force and free those humans. The island is undiscovered because it is so far from the shore of all the other continents. The question is: How do I stop my characters from just turning around and leaving the island in a self-built ship/raft? My first idea was to make it geographical difficult/impossible to leave by surrounding this island by a nearly closed ring of mountains (kinda in a U shape). An explanation for this could be that the island used to be a volcano that exploded (a real thing) and the mountain ring is what is left of the volcano. My problem with this idea: is it believable? Isn't it a bit too random for them to have been stranded exactly through the passage that is open? [Answer] **Sea monster.** [](https://i.stack.imgur.com/A3NUb.jpg) <https://www.belloflostsouls.net/2019/05/dd-monster-spotlight-dragon-turtles.html> D&D has so many great sea monsters and it is hard to get them any use if you stick to dungeons. I am fond of the dragon turtle. In your campaign, the turtle is charmed / compelled / enslaved by the demon. Your players winding up on the island was not by chance - the turtle brought their ship here. That is what it does. The demon and its servants go through a lot of humans and the turtle brings in new ones when it finds them. That is who lives in the village - the accumulated captures and their descendants. The turtle is also why they cannot leave. The village is built of their wrecked ships. Once the demon is defeated the dragon turtle is freed. It will leave. Or maybe the players can take possession of the artifact the demon used to enslave the turtle. Or if the turtle is intelligent enough to understand what has happened, it might be grateful - which would be a cool and unforeseen twist for your players. [Answer] Have you seen Cast Away? When the main character attempts his first escape from the island on a self built raft, he fails because outside of the lagoon the ocean is fierce and smashes the poorly built raft. Indeed, if you look at images of atolls and their lagoons, you will see that, while the lagoon is usually calm, the open sea is way more active. Should this not suffice, boost the waves in the ocean, to make them a more formidable obstacle. At the end your characters can hardly have the skills and knowledge to build an ocean proof boat. [Answer] # Session 0: Get Player Buy-In Probably your best bet is to have a [session 0](https://rpg.stackexchange.com/questions/105388/what-is-a-session-0) (always a good idea when you're getting ready to play an RPG) and discuss this with the players. Ask them if they have reasons why their characters might not want or be able to leave the island. You'll have a lot more buy-in if the players helped come up with the idea(s) themselves, but also if they agreed to a reason beforehand they're much less likely to try and circumvent it. If you just present an obstacle (even one you think is insurmountable) your players WILL eventually try and get around it. Finally, note that while this IS Meta-Gaming, Meta-Gaming isn't inherently a bad thing, though it is often made out to be. [Answer] # There's nothing to build with Much like Easter Island or Zavodovski Island, there are no trees, no reed beds, no large animals. Once you're there, either someone comes along with a boat to pick you up or you're staying for the foreseeable future. How you actually get your adventurers off such an island is a matter of plot, but I'm sure the big bad either has a portal you can play with once he's defeated or they can skin him and use his hide to build a boat. [Answer] A curse? The players wander into the town after the shipwreck, do regular adventurer stuff then eat, drink, make merry and have a Long Rest at the local Inn. But, the staff seem oddly apprehensive, constantly asking "are you *sure* you want all this free food we're offering?", "do you *definitely* want to stay in the luxury suite at the Inn?" In the morning, the locals - with much hand-wringing and apologising - explain that by their actions last night, the adventurers have fallen under the Island curse. Part of the curse prevents the islanders from telling or warning anyone in advance, but they do as much as they are *able* (not that it's much) to discourage people from staying. Leaving the island will kill our intrepid heroes - the further from the town they get, the more their health and stats with be drained. Encounters can be 'gated' by having different dungeons with sub-bosses whose defeat each lets them venture further and further afield. This also means that the final boss doesn't need to be ludicrously strong or anything - he just starts out far enough away that the adventurers can't initially reach him without being severely weakened. [Answer] ## TL;DR Requirements for building a reasonable ocean going ship are beyond a group of normal DnD characters, they don't have skills either to build it or to navigate it, and they have no knowledge of how far and in which direction any civilized land lies. Their only hope is that demons might have something that helps. Being lost on a remote island is no picnic even in 21st century. Much less in earlier settings. I welcome you to [Jules Verne](https://en.wikipedia.org/wiki/Jules_Verne)'s classical adventure novel "[The Mysterious Island](https://en.wikipedia.org/wiki/The_Mysterious_Island)" (1874). Warning, contains spoliers! In Mysterious Island, a group of five enterprising Americans escape Richmond, overran by Confederates during the American Civil war, by stealing a Confederate balloon. Unfortunately, this happens during a mega-storm, which blows (and crashes) their balloon near a most remote Pacific island. The whole story is about how they manage to build tools and make their life civilized. It is only possible because they have a talented engineer as their leader, and very capable rest of the group, including a sailor. In order to leave they need to have: * an ocean-faring ship * enough skilled crew to man it * skilled navigator to set course * enough supplies to last them through voyage * most importantly, knowledge how far and which direction to go Building an ocean-going vessel is not the same as a simple raft, the guys in the original novel can **only attempt to build an ocean-going ship, because they have a quality sailor**, which your team doesn't neccessarily have. Being five, they are a bit short on crew, but still can attempt it. But also only if at least one of them was a **skilled navigator**. But nevertheless, while they manage even to locate themselves by determining their latitude and longitude, they have **no maps**, and therefore **no idea** not only **how close and in which direction is any other land**, but also **if there is any land close enough to sail to**. Having **no compass**, they risk leaving the island only to sail in circles during any storm or fog, until their supplies run out and they **starve to death**. In their setting, there is a volcano, which lies dormant when they arrive, but wakes up later on. In your setting, there are demons, but, so far, they sound reasonably low key. Assuming they can build the ship or, since this is DnD, some magically enhanced means of leaving island, they will still be hampered by demons, who obviously don't want anyone to leave. Therefore they need to deal with demons first. And then you can think of *deus ex machina* which will allow them to leave. Probably makes sense to have it do with demons, maybe they have some artifacts that allow you to travel great distance over sea. Regarding islanders, the same things apply. Heck, they even could be remains of a larger crew from a shipwreck that landed on the same island some centuries ago. [Answer] The island is ruled by a demon and its monstrous servants, right? How many of those servants (or the demon itself, if it cares to do its own patrolling) can fly? A raft on the sea would be easily spotted - and easily *attacked* - by any sort of aerial patrols. Just make sure the PCs are aware of this, perhaps by having the townsfolk tell them stories about Old Bob who built a raft to try to escape and didn't even get out of sight of land before a trio of harpies found him. Two of the harpies hovered over him, out of bow range, while the third went to report and came back with a dragon, which burned Old Bob and his raft while half the town watched. Nobody else has dared to try building a raft since that happened. You can also reference the TV series [The Prisoner](https://en.wikipedia.org/wiki/The_Prisoner) for a less-lethal variation on this theme, where any attempts to escape are foiled by a man-sized balloon (Rover) which rises out of the water, encases the would-be escapee, and then the person wakes up back in The Village. (*Less*-lethal because I seem to recall at least one case where Rover pinned someone to the ground and suffocated them instead of bringing them back.) [Answer] Since nobody's mentioned it yet: ## Supplies They don't know how far away the next habitable land is, and they don't have the means to preserve fruit and potable water for more than 3 or 4 days. There is a surprising shortage of fish in the seas nearby, so they can't rely on the day's catch to supplement their stores [Answer] # What about **skills**? Building boat which will safely sail through stormy sea requires skills time and resources. Sailing and navigating it to get back also require skills. With some luck, your players doesn't have complete set of them. Obviously they could try to rely on folks who live on the island. But will they accept coin, or favour. # What about geography? There are many places around island with sharp rocks close to surface, which could rip bottom of the boat. Without map and skilled navigator getting to and off the island might be consider suicide. By addition, in this season, you have very strong sea currants which can drift boats towards rocks. # What about greed? Always where you have powerful monster/demon you have also treasure. Why not tell adventurers about them. Bear in mind, folks don't know magic and can exaggerate just to get some help. [Answer] ## Magic Considering the constant threat of being ritually sacrificed and/or eaten by their demon overlords, many inhabitants of the island will certainly consider the option to just leave the island and settle somewhere with less abusive neighbors. But the mighty demon lord certainly wouldn't want his livestock to escape. So he has to make sure that the villagers stay on the island. Whatever traps the villagers can just as well trap the heroes. This magic effect might also be the reason why the heroes stranded on the island despite succeeding on all their sailing skill checks. The magic effect might be something subtle like an implausible current which always washes ships back to shore or something more obvious like a magic energy barrier (which might or might not be visible from the outside). If you want that spell to work within the magic rules of DnD, you could ask on [Role-Playing Games Stack Exchange](https://rpg.stackexchange.com) for the best way to blockade an island using standard DnD spells or artifacts. But remember that you as the DM are not restricted to published material and are free to invent any new magic spells or effects when the plot requires them. Dealing with that magical escape prevention mechanism might be another subquest of your DnD campaign. Maybe it's generated by a magic artifact which needs to be found and destroyed? Maybe it's destroyed when the demon who cast it is defeated? Maybe the demons have some way to bypass it? [Answer] **You can't** People have free will. They can choose to leave and do nothing but being "adventurers" they are motivated by loot and XP so it's highly unlikely it will ever be an issue. The players spending several months of game time rolling for wind direction and random encounters plus building proficiency checks for the raft verses a storm and suddenly the demons will look far more interesting. Odds are you are trying to solve a problem you will never have. [Answer] First of all, this is D&D. If you are going out of your way to prevent players from leaving your setting, you'd be railroading your players. That's not what D&D is about. Having said that, why are your players there? If they're there because their ship got of course, and they are shipwrecked, your players have no motivation to stay on the island -- instead, they have lots of motivation to get off the island. They were on a ship going somewhere, so they already have a mission. Your players won't know there's an adventure in store for them on the island, they will think that getting off the island is the side-quest. Instead of going out of your way preventing them to leave the island, give them motivation to stay on the island. Perhaps they were rescued by the villagers (either from the sea, or from the beach when they were washed ashore). The villagers may turn to them for help. If your party is good aligned, they will be obliged to help. The villagers could keep the party's stuff as a ransom (many players will do anything to keep their magical items). The villagers could prevent the players from building a vessel. Or perhaps the party is kept hostage, to be given to the demons on their next visit. [Answer] Because of sea monsters/treacherous tides/other impassable conditions, the castaways are unable to safely leave (they might have tried and been turned back). There is a way out but only the villagers know it. But they have been unable to leave (or save themselves from the demons) because they lacked something the castaways have unknowingly brought with them. ## The only way out is if the castaways and the villagers work together. The villagers, not being fools, insist that everyone goes or no one goes. The castaways, not being selfish jerks, agree. Now the castaways must, with the help of some villagers, defeat the demons. Once that's done, they can work to build the required number of sea-worthy crafts (for those that wish to leave) and get the hell out of there. [Answer] [Reefs](https://en.wikipedia.org/wiki/Reef), while barrier reefs often shelter near shore waters creating calm lagoons they do so by breaking the energy of the ocean in walls of waves. Without local knowledge attempting passage through such reefs is often suicidal, there's a reason that over 1600 ships have been lost on the [Great Barrier Reef](https://en.wikipedia.org/wiki/Great_Barrier_Reef). If the locals don't take to sea there is no local knowledge and the PCs simply *can't* get out, until they get teleport spells of course. Alternately depending on the time constraints you need to create, it could simply be the [wet season](https://en.wikipedia.org/wiki/Wet_season) thereabouts. With storm clouds constantly haunting the horizon and heavy rains daily no-one is willing to take ship least they get hammered flat by the weather, this usually only lasts for a matter of months however. [Answer] ## Difficult ocean voyage Building and navigating a long-distance ocean-going vessel aren't particularly easy skills to just develop on your own just because you need them. If the players were on a long distance voyage, many days away from any safe land when they were wrecked on this island, then this would be quite a difficult and time-consuming endeavour. Even just gathering enough supplies that they don't starve would be a major effort. Of course, this point largely relies on the players and their characters realising this and so deciding not to try. You don't really want to have to *actually* use the difficulty of the voyage against them, because if you do the story simply ends with them drowning at sea, which doesn't work. If the players make a quick raft and launch it immediately, despite your telling them how far their previous voyage had travelled since they last saw land, you can have them immediately wrecked close enough to the island that they can make it back. If they take time on a more serious effort, that gives you time for: ## The demons don't want people leaving Whether the demons' rituals are building up to some particular plan, or they're just living here feeding on the inhabitants, they don't want it known in the world outside this island that they are here. Perhaps major countries or religions would arrive in force to destroy them if their presence is known. Perhaps not, but the demons fear it is possible. So the demons actively patrol the island for people attempting to leave. The party's ship-building camp might be attacked by a small group of demons one night. When it becomes clear the PCs are capable of putting up a good fight, the demons will attack in greater force. You can push this as far as making it so that in order to be free from demon attacks in order to finish building and stocking their ship, they essentially have to defeat the demonic forces on the island anyway; the demons through everything they have at the party, up-to and including the evil overlord attacking in person. No party I've ever played with would *actually* make the GM do that though; they will hopefully display *some* interest in what is obviously the plot the GM has in mind and go chasing up what the demons are doing here. This works for the people living on the island too; they've learned the hard way that the surest way to bring the attention of the demons is to start building a ship. ## Don't wait for the party to discover the town People from the town are aware that a ship has wrecked on or near the island (perhaps they saw it go down, or maybe they've just noticed bits of wreckage washing ashore). So there are searchers who discover the party's camp (either organised searchers looking for survivors, or opportunistic ones looking for salvage). Or maybe some foragers or farmers happen to spot the camp as they're heading back to the town, and can tell the party it's madness to sleep outside the walls because the demons always come at night. Or their campfire was seen on the first night, so a patrol of soldiers from the town come to investigate, in case it was a sign of demonic activity. If the players declare they want to spend many days working on a ship on the beach, without exploring the island, that gives you plenty of time for other groups on the island to believably discover them, and therefore introduce the framework of your intended story. ## The players want an interesting story Basically, the best way to make sure they don't spend game time figuring out how to build a ship is to give them something more interesting to do. D&D doesn't really have any tools to shipbuilding an interesting gaming experience anyway, so this isn't hard. Just have your plot make contact with the players, and they'll likely want to follow it. [Answer] [Shipworms](https://en.wikipedia.org/wiki/Shipworms) - they live in the ocean surrounding your island and are well-known to eat through wood - the fishing boats & docks constantly develop leaks & need to be repaired, and no sane person ever goes farther than they can swim back because of this risk [Answer] ## The demon has warped space around the island I'm assuming that the villagers on this island would also try to leave, given the opportunity, and they've had way more time to build a ship or raft than the players will. So what's keeping them there? Inspired by legends of the mysterious "black hole", the demon lord Kazuzu has crafted a powerful spell. Ships are free to *arrive* at the island, but anyone who attempts to sail *away* from the island will inevitably find themselves sailing back towards it. Or, at best, circling it. Like the interior of a black hole, space is so bent that there is literally no path in any direction that leads "out". The villagers have small boats they use for fishing—they *need* the fish, since their crops keep getting trampled by monsters—but they've learned by now that escape is impossible. So they don't even try. The only way off the island is to break the spell. The only way to break the spell is to defeat Kazuzu. [Answer] For another D&D inspired solution the Island exists in a pocket dimension similar to the Demi Plane of Dread that the Ravenloft setting exists in. In that setting player characters can pass into the Demi Plane through the mists and are prevented from leaving it by the Dark Powers that control the area. Their escape can equally be allowed at the whim of those powers. In Ravenloft players attempting to leave find themselves returned to were they started, teleport and similar spells with targets outside fail. In the case of your Island it could be a plane that your party have crossed into, and cannot leave until the demon is defeated. Perhaps its presence causes the plane to exist, perhaps it was imprisoned there by a higher power. [Answer] Its seems like a combination of all of the above is the best answer Reefs, shoals, and man-eating critters make simple rafts too dangerous. But, there aren't proper tools to build a real boat than can make the trip safely. But, if they succeed in the quest, then they get tools to build a boat if they need it. Or they get a boat as part of the payoff. Maybe magic restores their lost ship. Or their ship was bewitched or ensorcelled, and they only think it sunk, but the forces that brought them to this island to solve the curse of the deadly danger will reveal themselves and give them back their boat. [Answer] A few things could be used. **Isolation** You could make the island so far from the mainland that it would be impossible to sail back. If your players were on a shipping route, maybe a strong storm caused them to veer waay off course. Think Point Nemo, but an island. **Strong Currents** Currents can be used to carry people to distant places, but can also hinder travel. Perhaps your island sits near a strong current that stops players from heading towards the mainland, and carries them to a latitude where the winds stagnate (look up horse latitudes). **Deadly Storms** The open ocean is not known for being a calm place. Your players could attempt to leave the island but find that any raft they build cannot withstand the power of mother nature. This brings me back to the first point. The storm could cause them to be isolated and makes it nearly impossible to leave. **Sea Monsters** What could possible make the ocean less inviting? Giant ocean monsters would definitely be a roadblock in trying to escape. Perhaps this sea monster lurks near the island and traps ships on the island via artificial currents. These are just a few options, and maybe the best option would be to combine a few. Just make sure the story is interesting enough that the players only think of escaping as a passing thought. [Answer] **Personal motivation.** So your players are shipwrecked on an island. They are hurt, they are incapacitated. In fact, they only survive because X helps them. X rescues them with X's little boat, X shelters them in X's little house, X nourishes them from X's little supplies. Then X gets culled by the demons, while X's children (who the characters never saw, because they are away in the big city getting an education) are next up for culling. Last words of X before the minions strike: 'Save my children'. Should the characters now still want to leave the island without doing something about the demons and their minions, allow them their chickenhearted escape and later hit them with Guilt (tm) until they return. [Answer] Ursula K. LeGuin, in her Earthsea trilogy, had the Roke Wind, which prevented anyone wishing to do harm to the island of Roke from sailing too near it. It would sink their ship or blow it away. Do this in reverse. Personally, I would create a few interesting places that the adventurers could go if they tried to escape. For example, there is a permanent dip in the jet stream due to an ancient enchantment, because the air was needed for the forge of an underworld demon to operate his forge. That causes an updraft that will carry their makeshift raft up into the air and deposite them on a floating island, suspended on a stable point over the updraft coming out of the netherworld. The only escape from there is either a really long rope, a parachute, a flying carpet, or training a large flying bird to carry them back down. [Answer] If they have the skills to pass the checks to build the ship and leave let them. Then give them a monster, then tsunami, ect otherwise they don't leave the island because either it moves because it's ontop of an animal making the land they came from further and further away from them so they can't sail there with whatever supplies they can muster. Or else they just can't leave. Some island tribes did not develop boats to move into deep ocean and your players may not have the skills necessary to build a deep faring boat much less supplies of wood palm trees are not the same as ash wood ect. They don't know how to bend or treat the wood there is a lot of stuff that goes into making ye old boat and big sea worth ye old boat at that. They also need supplies for however many weeks or months to get back home and they need to navigate well to do that if you don't have NPCs or the players themselves can't do these things they'll all die (you could let them) the locals will not let them take all their food for months long voyages and you players also need to preserve the food! They need another boat to find them, they need a magical portal to teleport them off the island, or maybe a flying creature? All of these things they don't have and won't have if they don't go on with the quest! ]

[Question] [ ## Context [Members of my race](https://worldbuilding.stackexchange.com/questions/40596/how-can-i-explain-why-my-race-has-genders-but-cant-reproduce) can live virtually infinite lives (they still have to drink, eat, and can be killed, but don't age and are immune/really resistant to disease) but are unable to reproduce. They used to be "manually" created by a god, who has not manifested since hundreds of years ago, thus not giving birth to any new member of this race ever since. # Question However I feel like this applies to pretty much any long-lived-but-slow-at-reproducing race (such as classic Tolkien-like elves), so the matter is more general: **Why would a long lived race decide to wage war and fight others, knowing that (regardless of the outcome) they will be losing many more people than they will be able to give birth to in a *long* time?** This seems pretty common in fantasy, but I feel like such a race would be much more sensitive towards even the smallest losses, since their low fertility makes extinction a potential risk. **I want to know what good reasons this race would have to enter a war or generally have high aggression** (not only the obvious ones like being forced to choose between a defensive war and annihilation), because I would like the race to be fairly warlike despite the risks. To be clearer about what I mean with "having a reason to fight": for example, one idea might be having the god create them with an innate instinct to fight (like Orcs and Half-orcs in D&D, for example) but I'm afraid that would sound too cliché. I don't want them to be utterly self-destructive, since they would go extinct in a matter of years, just prone to and good at fighting. [Answer] They're immortals, they've had thousands of years to hone their skills. They don't die easily. They're all veterans of countless battles and know when to retreat. For humans losing mere dozens out of thousands in a pitched battle is a fantastic success. For them even one or two losses is a rare and sad event. Any normal attrition rate would leave their numbers depleted too fast. So, with that in mind there's quite a few options... **Give them something to gain from battle** They are immortal, yes, but over the eons the life force inside them slowly stagnates. It will never kill them but life becomes a dull grey as the centuries wear on. How can they negate this slow dulling of the world? With vivid and extreme experiences, fear, sweat, blood. Or perhaps they can sap a trace of the spiritual energy away from a foe defeated in honorable combat to invigorate their own and bring colour back into their experience of the world. Which could be used as a mechanism to effectively make them *need* battle every few years/decades/centuries even if they're demure peaceful artists much of the rest of the time. **Race of paladins** They are the product of a god, heretics are inimical to their very souls and must be destroyed They remained at peace for a long time... until heresy spread through neighboring kingdoms. Now with the righteous fire of their convictions burning through their veins they are overwhelmingly compelled to crush the unclean heretics who would abandon the ways of their god. **War as suicide or extreme sport** The very very old get bored and lose their love of life. As is the tradition of their people taking their own life is seen as an affront to their gods gift of life and dying at the hands of a weakling would shame them. So they go to war until they meet an opponent who can defeat them without it shaming them. [Answer] As have been mentioned by @Murphey and @Twelth, war can be a relief of boredom and they will be **very** good at it. As other people have mentioned, I can't believe that they would form a battle line and go numbers to numbers against a foe. They would use all of their skill that they've developed. Also, there might only be one or two in a battle. They run in from a sideline and kill a bunch and then leave. Or they sit back and pick off people with a bow. You might have one each on both sides of the battle in a contest with each other. They wouldn't fight each other but would be keeping score. To make things interesting, they might put restrictions on themselves like: only arrows through the left eye count. They would make awesome: scouts, assassins, and **generals**. Imagine two immortals playing chess with real people. Heck, they are probably playing Settlers of Cattan or Risk with nations. Then, when they get bored, they join a fight and put enough restrictions on themselves to make it interesting. [Answer] **They don't die the way we do** Your fantasy/scifi races are under no obligation to resemble anything on Earth. You and I have all these fleshy organs arranged in a delicate balance that can be upset in any of a million ways - we seem to cease to function at the slightest provocation. Your race, however, may not. Perhaps they have one of these features; * They have bodies with total regeneration. They can (with time) regrow limbs, organs, bones, *everything* as long as their "brain(s?)" remain intact. You and I fear amputation and dismemberment, these guys can fight with no regard for losing some pieces here or there - because if even a small part of them survives they can regrow good-as-new. * They go into advanced hibernation. Maybe to your guys "death" is merely a hibernation state in which their body slumps over, but can be easily revived by a healer. It would have to be extremely difficult to actually destroy their brains (or, souls, or whatever); perhaps the only thing that can truly destroy their "essence" is a specific acid that's difficult to make (depending on how hard or soft your magic/science is). * Death is a normal part of life. Plenty of animals on Earth go through some [pretty excruciating procedures](https://en.wikipedia.org/wiki/Pupa) that involve totally destroying their old bodies in order to construct new ones. Maybe your race *needs* to be killed so that they can be magically reborn in the next phase of their life. **It's worse if you kill them** Nature has a lot of relationships between species that is symbiotic at best, parasitic at worst, and usually somewhere in between. The same might be true for your race - nobody seriously fights them because their deaths impact the wider world around them. * The death of these beings curses the earth where their body fell. * Killing them chips away at a more fundamental protection of the world (some *worse* god or entity eating the world, perhaps?). * Each one collects the souls of his victims in a little internal organ that destroys the souls if it's ruptured or crushed, and the only way to save the souls of his victims is to capture him and perform a delicate procedure to free them. His enemies refuse to outright kill him on the battlefield because it would mean the damnation of his hundreds of victims. * They're the gut flora of the world. Perhaps they emit some kind of spore or something that the world *needs* in order to survive. The forests would die, the crops would rot on the vine, or the air would become putrid. [Answer] **Resources** **Your race of immortals still needs to eat/drink and maintain a certain level of technology.** No matter how far advanced the biology of your mortals it would be difficult to alleviate the need for food and water. This constraint is often cited as one of the features needed to differentiate living and non-living phenomena. Human beings are highly dependent on technology. We digest our food by using fire, possibly allowing for a larger brain as we do not need support a more costly digestive track. Alternately historical records indicate societies with longer lifespans secure things like oil from lower lifespan societes (examples the first and second gulf war, Nazi agression towards the, I believe, the Caucuses). Further, longer lived races would be better off hoarding. If you need aspirin now, you would be better off buying bulk quantities as this would suggest a need in the future. This would become even more of a problem if there is a known limited amount of aspirin (which there isn't, but you get the point). [Answer] They're like people. They don't generally act rationally, consider the long-term consequences of their actions, or worry about the distant future, especially if there are more immediate concerns. In short, engaging in war to our long-term detriment isn't something you need to explain, so much as it's a fact of life (as we know it). Most of what you've said about this race could be said about humans. Consider: > > long-lived-but-slow-at-reproducing race > > > Humans are both long-lived and slow at reproducing, compared to other life on this planet, both historically and in modern times. Historically, we had slow growth rates due to factors like high infant and childhood fatality rates; in modern times, the reasons are more economic, but either way, we reproduce much more slowly than most other other species, even other mammals. [Consider that medical technology in modern times has given the human population the highest growth in history, at ~2.1% per year](https://ourworldindata.org/world-population-growth). That's pretty slow, and historically it's been well less than 1% per year. We are also one of the longer-lived species (of animal life) on the planet and are an extreme outlier when you consider our physical size and metabolism. (Lifespans generally increase with increasing both body size and lower metabolic rates.) > > Why would a long lived race decide to wage war and fight others, knowing that (regardless of the outcome) they will be losing many more people than they will be able to give birth to in a long time? > > > That description seems like it fits the human experience with war, too. Big, modern wars like WWI and WII are self-evident examples but even older wars set back population growth, economies, progress and so on by generations too. Casualties might have been lower in the past, but there were fewer people too, and the disease caused by the large grouping of people into armies historically killed more people than actual combat. When you get right down to it, the difference between your fantasy race and people is smaller than the similarities, and I think your focus on that difference makes you miss the similarities. Your question makes an implicit assumption here that people actually consider such things before going to war (or are generally rational, for that matter), but the evidence we have from examining our own past indicates that neither of these things are actually true. If you dig into the politics and power dynamics it gets stickier, but makes an even stronger case against those assumptions. The people in power, the people declaring the wars are self-interested (like all people), and the long-term good of the species or society or whoever is much less important than whether the war is in the self-interest (or perceived self-interest) of the people making the decisions. So, why would a long-lived race be aggressive and warlike, despite the dangers and self-detriment? For the very same reasons that the long-lived species we call "human" is aggressive and warlike, despite the dangers and self-detriment. :) [Answer] These immortals have some advantages to these wars: Practice practice practice. When you have thousands of years to hone a skill, you get extremely good at it. With a bow, by year one or two (a blink of an eye to them) they will be proficient. By year 5 they will be experts. By year 10 they can start to challenge today's Olympic-grade archers. By year 20 they will be the best Earth has to offer. By year 100 they will be banking arrows off surrounding terrain and impaling 3 enemies with a single arrow...and then it's time to learn to ride a horse. Infinite life spans allow for a level of training humans today can't really perceive...by the time they've had 500 years of horseback archery practice, then they can get to training melee weapons. Equipment. A similar line of thought above, when your master armourer has several millennia to perfect his craft before a single piece of equipment they create is actually used, you can guarantee the equipment they make is beyond what a mortal could consider. Guerrilla. I actually dislike the image of the traditional 'elven' army...you have troops that make Earths Mongol horde look new to horseback riding and bow use that make WWII era rifles seem ineffective...why engage in a classical battle when you could be harassing their formations long before the battle starts. Hit their troops as they march to war, as they camp, and as they try to supply themselves. In a hit-and-run sense (do the damage and get out before you take losses), these elves would win wars before the main battle is engaged. Remember time can become a weapon to these immortals as well...they don't have to take risky moves that sacrifice lives to save time. They can engage in tactics that draw out conflicts and strain the oppositions resources (money, lives, food, and everything else needed in war). A particularly strong enemy king won't be around in 50 years, why destroy what time will take down for you? With all that said: *I want to know what good reasons this race would have to enter a war or generally have high "fightiness"* 1) As prefaced - their training, armour, and tactics can all be adapted to greatly limit the number losses they take...they may not view war as the high casualty event that other races see it as. 2) Immortals still need resources. Lacking resources you need still remains the number one reason for war. 3) Boredom. If you're training for millennia, you are going to want to put your skills to use. War becomes sport and entertainment and glory. 4) Power. If you're going to live for millennia, you may want to leave your imprint on this world over an extended time frame...seize power and shape the world to what you want it to be. [Answer] **The god that created them expected to create more.** The way you describe these beings, they pretty much will live forever, *except* for the case where they are outright killed, or die from starvation or thirst. Death from starvation or thirst is a problem with its roots in limited resources in their world. If you only add (and never remove) individuals, assuming that each individual requires roughly the same amount of resources (specifically in this case, food and water) to live, then **resource usage grows linearly with number of individuals. However, a world can only provide so much resources, so at some point starvation becomes a real issue.** Dying from starvation is not exactly pleasant. Dying from thirst is perhaps even worse. Since the god expected to create more of these beings, the god planned the beings with population-control measures built in. **One obvious such measure is to have your beings fight each other** to the point that one, or both, will no longer be a drain on resources. This can be coupled with any way you prefer of making it more palatable, including the lofty concept of "honor". This doesn't need to involve all-out fighting in an "everyone against everyone" style; only sufficient to compensate for the rate at which the god expected to create more of these beings. If it takes a long time to create one, then the rate of fighting will be low; if it's a trivial task, then the rate of fighting will be high. Adjust to taste. Besides, it makes for great fun to watch. [Just ask the old Romans.](https://en.wikipedia.org/wiki/Colosseum#Use) Your god might, too, have enjoyed watching the battles. [Answer] What if the god you talk about needs sacrifices to summon them? They only appear to create more beings when x amount of blood has been spilt. So to avoid extinction by the occasional accident or starvation, they have to fight to bring their god back. If they are good at it, they will grow the population every time they bring the god back, if they are bad they will head towards extinction faster. There could also be other incentives for bringing the god back. Like maybe everyone who dies only goes to the after life if the god comes back to take them there. So Tom trips and falls off a cliff, now his entire people go to war to to bring the god back so Tom can go to heaven. It's a silly example, but hopefully you get the idea. [Answer] First off, understand that it is likely that you will underplay the brutality of war in the process of trying to create a race which intentionally engages in war. Whatever you create will ring hollow, because the war you create must not be as bad as war truly is. With that in mind, I would recommend using the view of life as a drama or a play as the basis for this species. You can draw content from the Hindu belief system, for they view life in such a way, though you may have to contort it to create the warlike nature you seek. *(disclaimer: in this answer, I am drawing on a religion that I do not profess to, and have not deeply studied. Seek guidance if you want to learn about the actual religion and its beliefs)* In this sense, the members of this race seek to lose themselves in the play of life itself around them. They know that all the folly of the lower-lifespan species around them is just folly, but they want to forget. They want to be gripped by the excitement of the actors, until they're on the edge of their seats. They want to get so involved that they lose track of where they are and what they are. In the Hindu belief system this process occurs over the course of roughly 4 million years. Near the end of the cyclical play, the kali yuga period occurs, roughly 400 thousand years long: a period of strife. Your immortal race may find that, as they approach this age, all methods they have found to lose themselves in the great play have rung hollow. The only aspects which seem truly immersive are those of war. As long as your race is engaging in war, they feel alive. If they stop, they soon begin to see that the play is just a play, which would be quite undesirable. The Hindu cycle is 4 million years. If you stretched that out to billions of years, watching stars born and die, I think you could imagine quite a brutal warlike race, suffering like this for billions of years. But the rational for doing so is pure psychology: the desire to get lost in the play of life. So you can choose to make it as religious or as scientific as you please. [Answer] **Among each other, they don't fight wars to the death.** They are a long lived race that views the lives of their own as sacred, but they still have long-standing arguments that can be remembered for centuries. Though they fight among each other in an attempt to trade territory or seek payment for transgressions, their fights among each other are not intended to be fatal, but they pride themselves in bringing each other close, but not to, death. **As mortals die more easily, the immortals are unintentionally more lethal** They end up very skilled in combat because of the above, but they know that shorter lived races that show any capacity for intellect do fight to the death in war. Additionally, mortal races likely know that these immortals have had millennia to master fighting, so they fight to the death at all costs if forced to fight. The immortals don't try to fight to the death, but the tenacity of the mortals and the lethality of the immortals causes issues. **They see mortals as dangerous in hordes** This forces any wars with the mortals to be extremely dangerous, as they throw thousands against single immortals when possible. The immortals may seek to keep the numbers of mortals down due to this problem, leading them to 'pre-emptive' warfare. **Their society thus promotes battle skill** With the way they fight among their own battle skills are highly valued and paramount. Bring the enemy close to death, but not to to force them to concede victory. Against mortals, this forces the mortals to be compliant or especially aggressive. It isn't that they chase a defensive war. The issue of how they fight with each other changes their lethality to others. [Answer] A few reasons that others have not touched upon or were touched on tangentially: ## 1. Literal Bloodthirst Like vampires, they require the large-scale replenishment of external blood and can absorb it via shed blood. Battles and war are the obvious solution, though some will commit mass murder. Without mortal blood, they sink into a torpor that can drive them insane from boredom. ## 2. Divine Worship Mortals consider them virtual gods since they have ruled from the ancient days, eternal Pharoah style. Each immortal leads a city, and these cities go to war on a frequent basis as the warlike immortals compete for glory or gold or simple points in a 'game' that has lasted millenia. ## 3. There can only be One Yes, *[Highlander](https://en.wikipedia.org/wiki/Highlander_(film))* style. The last remaining immortal will gain a wish or become a new god. This has been decreed by divine power. [Answer] Here is an answer I didn't see in any other posts: ### 1) Anti-natalism (It is immoral to have children). Your race believes it is immoral to have children. Unless your world is an utopian one, bringing a new consciousness into the world risks new pain and suffering. Non-existence is better than risking increasing the suffering in the world, and so races that reproduce must be culled or subjugated to prevent future births. Since members of your race cannot choose to reproduce, they feel uniquely qualified to right this universal wrong, often through war. *Edit*: Since is it possible for a reproducing creature to have infinite descendants, even a small probability of a life of suffering for each descendant sums to much greater suffering than the suffering of one creature. Therefore it is the lesser of two evils to end the creatures life before they reproduce. At the very least invade their lands and sterilize them. Reference to this idea here: [Anti-natalaism](https://en.wikipedia.org/wiki/Antinatalism) [Answer] They don't think about death as an end. They were created by a god or god-like figure. They were not born to begin with and they do not age.They take life for granted, and for good reason too. Their purpose in life is what their god created them for. Whether it is for a crusade, or simply to stir up trouble. Whatever the reasons the god has need not be known, unless your god has proclaimed them to the world. Death is not something to be mourned in you warrior race. It is celebrated as those who died have achieved their goal in life and returned to their god. Not only do they not age, but they are also strong. Each of your surviving warriors has an uncanny ability to grasp the military and martial arts, and for one to die someone must have really wanted them dead. That is to say that when one warrior dies, those who've witnessed learn from it and become harder to kill, and possibly spread the new knowledge to other survivors. With such a trait it is possible that your warrior race covets a death which is witnessed by their fellow warriors to strengthen the entire race, and dying alone is the most shameful death. Your warriors fight because its what they were created for. They often try to challenge those who are on top simply for the opportunity to become stronger in death. As a consequence though I would also be inclined to make this race not interested in fighting the weak. They are feared because of their aggressiveness and uncanny skill, but they do not desire a death which nothing will be learned from, and every battle has its risks. They are fully aware that eventually they will disappear. There was never a promise for more warriors to be created if they were to die. [Answer] **War = Life** Perhaps the immortal race must transform itself between a cycle of forms to stay immortal, and one of these forms is exceptionally aggressive. This could be an interesting source of friction between the aggressive forms and the rest of the artistic/scientific/leadership/etc. forms. (Somewhat inspired by *The Mote in God's Eye* by Larry Niven.) **They Taste Good** Maybe the immortal species consider other races as a critical food source. I imagine the rest of us would react violently to humans being farmed, and the immortals would want to preserve their source of nourishment. Consuming warlike tribal humans or orcs may have added a huge amount of aggressive behavior to the immortals. (Loosely inspired by *The Book of the Long Sun* by Gene Wolfe.) **Hardware Bug** Maybe a biological imperative causes them to be more territorial over time. When they were first created, their creator endowed gave them the potential for war but endowed them with a gland that makes a hormone that keeps them calm, happy, and peaceful. Unfortunately, over time, the creator did not realize these glands would atrophy and gradually make them more warlike. Having lived essentially forever, they are *very* aggressive. **Self Mutilation** Continuing the hormonal idea... Maybe there was a prior race that posed a threat to their existence. The immortals were too peaceful to fight back, but they also knew about this gland and figured out how to remove/suppress it to save themselves. Unfortunately, this act was permanent, and now they are forever aggressive. How tragic! Uncovering the happy past would turn these immortals from warmongering villains into tragic victims. This would yield a nice plot point to restore the immortals to their prior, peaceful ways. **Temper Tantrums** Another alternative: the immortals, despite having lived a long, long time, are actually just in the infant/child/pupa stage of their lives. They simply do not have the capacity to develop the same morals than the rest of the races. Human children can be prone to intense fits of rage. Combine this with an infinite amount of knowledge and power. Frightening! **Morals** Speaking of morals, I have no idea what the moral code of an immortal race would be. Over millions of years, I expect many people would have developed way past what we consider to be "right". They might consider it a moral imperative to kill every other sentient race because we are mortal and therefore just animals. As a mortal, I expect that I would find them quite immoral immortals. **Self-Preservation** I think the immortals would see the mortal races as a clear and present danger. The immortals would likely need to cull the rest of us periodically to prevent resource starvation as we breed without end. Hunting licenses, anyone? 10 bag limits? Or, perhaps they believe that the only answer is extinction for the rest of us, and they will stop at nothing to achieve it. Personally, I would be terrified if there was a sentient species that could breed a new generation every week and competed with humanity for the same resources. To them, we would be the immortals. How would we react to essentially being overrun? Would killing these critters be justifiable as self-preservation? [Answer] ## Long memories "That valley was ours five thousand years ago. I remember well the day the humans drove us out. Preparations took a while, but now we are ready. WE WILL TAKE IT BACK!" "That mountain over there was ours too. My friend Whatstheirname has told me about how the dwarfs stole it ten thousand years ago. WE WILL TAKE IT BACK!" [Answer] **What would the Krogan do?** Your proposed race sounds very similar to the [Krogan](https://en.wikipedia.org/wiki/Krogan) from the Mass Effect series of games. The Krogan are extremely aggressive, warlike and hard to kill (regenerating), with their race suffering from "the Genophage" which reduces their reproductive rate. There doesn't have to be just one reason for your long-lived rowdies to start wars, their situation lends itself to several motives: 1. The Mercenaries and Criminals - you are a near-immortal thug with nothing else to live for. Why not get paid for doing what you enjoy and are really good at (after hundreds of years of practice) - killing the squishy races! 2. The Cure Seekers - your race may be individually tough but the fast breeders will overwhelm you with numbers if you don't come up with a cure for your god's apparent loss of power. The populations of the fast-breeders have increased over the last few hundred years and your god is no longer in evidence. Your theory is that the strength of a god relative to the other gods is proportional to the number of followers. In order to get your god back in the game you and your followers need to reduce the population of the other races. *A lot.* 3. The Security Dictatorship - the only way to protect yourself and (some) of your race is to climb to the top of the pile and keep yourself there. You read the local equivalents of *The Art of War* and *The Prince* over a hundred years ago and have been planning your campaign to take control of the continent since, including rabble rousing and promoting aggressive behaviour among your own people. The time to launch your campaign is *now*. (This is more inspired by the Shaa from the *[Dread Empire's Fall](https://en.wikipedia.org/wiki/Dread_Empire%27s_Fall)* series of novels by Walter John Williams than the Krogan.) Finally, there is the entire concept of risk-taking. Humans learn, as they mature, how dangerous certain activities are. These activities include engaging in combat - as the saying goes, there are bold soldiers and there are old soldiers, but no bold, old soldiers. If you are almost unkillable, your assessment of what activities are unacceptably risky will be very different to those of a human. There will be lots of bold, old soldiers with combat abilities that have increased, not diminished, compared to their youth. [Answer] **Yawn...** Life is long, mundane, and largely very boring. What else is there to do except gamble your immortality on adventure and conquest? **A Greater Power** There are things in this world, Horatio, far more important than your life or mine. We were put in this world to \_\_\_\_\_\_\_\_\_\_\_\_\_ and we must not fail. Even if we must throw our bodies on the pyre of righteousness, we must do it! **Ethical Priorities** It comes down to what's important and why. We children of the Darwinian age posit survival of the species above all else. If there's an attractive after-life and no disincentive to rush to it, I'd be surprised if a long-natural-lived species didn't speed up their own destruction. [Answer] Their creator *made* them aggressive. Too aggressive. Their original purpose was to be enforcers, soldiers, warriors. Perhaps the leadership for lesser armies as well (Think of a tribe of goblins in D&D led by a single hobgoblin). They are strong and tough. They heal quickly. The tire slowly. They don't die easily. Early on, the god would simply make more of them after each battle. Perhaps the god would resurrect the fallen as well. Now? The god is silent. No one knows why the creator no longer takes an active hand in their battles, and some of the greatest warriors in memory number among the fallen. Thus, their ultimate destiny is extinction. However, that is the future, and this story is in the present. [Answer] **They are arrogant.** Members of an immortal race individually hand-crafted by a god (so to speak... you mentioned each were manually created) probably have a pretty high opinion of themselves. Combine that with the superior equipment and skills that other answers have mentioned and you have a people that probably view other races as savages at best. They may view even the slightest perceived insult as a provocation. War could be viewed as a way to "teach those vermin their place". [Answer] ## Honor Some things are more important than survival, and chief among these is honor. If someone insults your 10,000 year-old ancestral name, encroaches upon your ancient lands, or speaks ill of your creator, it cannot be allowed to stand. You did not seek this fight, but you will pursue it with grim determination, and show the world that you will tolerate no disrespect. Your race wasn't created to merely survive. They were created to be a great power in the world, which means a willingness to pick up arms and fight when duty calls. Better to burn bright for a while than to burn dimly forever. [Answer] Natural selection. Of a kind. Over the ages these immortals where generated by their god. Some of them shyed from conflict. Others embraced it. Others where neutral. The conflict-scared and neutral where wiped out century after century. Those that survived formed empires and led their peons against other immortals and against free peoples. Most of those that failed to form empires where killed and enslaved by other immortals and free people's. Those that live are those that lived. Violence is only against survival when the alternative isn't worse. War is worse for non-combatants than it is for soldiers. There will be some immortals that are peaceful and hate war, but they are far outnumbered. Of them, the vast majority are immortals that have been broken and enslaved by free peoples or other immortals. A minority of a minority are the peace-loving immortals that remain free and indepenent. With the end of new immortals, the dynamics have changed a bit. But immortals are also creatures of habit, and adjusting to the new era isn't for everyone. [Answer] Make them extremely religious. They are directly created by a God, so they are in touch with divinity. They are keepers of the righteous belief and the return of the God is directly linked to the "spark of belief". Then you can introduce a "satanic" group that they battle, or if other intelligent species exist (like normal people) they can fight the decadent inferior competitors. Or the "humans" rebel and do not help them maintain the belief in the God and they need to fight to crush the rebellions. You created a very interesting introduction with a direct manifestation of divinity. Why not use it to motivate them? That way you can link the very creation of new ones to their need to fight now (they need to keep the religious belief in their God so he will return and make more). The future reward justifies the sacrifices now. [Answer] The standout reason for me that species may be war-focused and violent is that their species has become zealously defensive of their longevity. All it would take is one charismatic member of their species to spread propaganda that all other species would take the ability if they could, and in only a couple of generations' time, extermination of other species' would become a normalised behaviour, global effort, or simply tradition. Perhaps if an attribute of their being grants them their long life, other species may have hunted them in the past to gain it, or at least, stories of such may be circulated to encourage their defense. Tl;dr - overzealous, almost religious defensiveness, used to validate violence and holocaustic extermination. [Answer] The best defense is a good offense. They could view all mortal races as warlike children who cannot be peacefully coexisted with. War would be inevitable. the only question would be the timing. The immortals' chances of victory are much greater if they attack mortal enemies by surprise and when those mortals are fewest in number. Most populations of intelligent creatures tend to grow over time, so the logical move is to wipe them out immediately. A tribe or nation of mortals might respect the immortal race and live in peaceful harmony. But it is is the nature of mortal people to change over time. Eventually, those mortals will experience a period of violent expansionism. It makes no sense for the immortals to wait for that to happen. This would work well unless you intend for this immortal race to also be mindlessly aggressive toward other immortal races. Though, it would only take a grudge in that case to justify perpetual hatred and mistrust. [Answer] There are the classics like money, resources, land, slaves,... However, they could wage war against another nation of weaker beings but who reproduce very easily (a race that relies on swarm tactics). If your "immortal" race wants to avoid being outnumbered by this potential enemy, they could wage war to try to make this swarming race extinct, especially if there are hostilities (like some sort of cold war). [Answer] well, the most obvious reason is "because more would die/suffer if they don't" So if you can reason that the enemy wants to kill all of your race, then war doesn't seem so bad an alternative. And they might not put survival as their topmost value - i.e. people die all the time for imaginary gods or similar values - why should be people who live longer be excluded from such things? [Answer] **Entertainment** Their longevity allows them to hone their craft, more so than other races. It isn't far off to consider most of their race could be masters at the art of combat they so choose. And with longevity, can come the blandness of everyday routine. Practising combat everyday, watering the garden, eating.. all of it becomes a chore once you do it hundred years or so. Perhaps your race is fight-y because it adds that bit of spice to their lives. Combat is rarely the same each time, perhaps they seek a the cliche'd worthy opponent amongst the rest of the lesser lived races. **Culture/Status** Perhaps their kind's culture revolves around combat. One's status is heightened depending on how many other esteemed warriors you've felled/defeated. It isn't a required feat among them, being combat ready is already a good quality to have but to rise higher, one must prove their mettle. This may be similar to most Orc-y races. **Self-Imposed Authority** They could, say, see themselves as the higher race among the rest and come to blows with other races simply because of their beliefs. I would go to say that they're protectors of the earth, ridding the world of pests. Take the elves from Lorwyn/Shadowmoor of Magic: the Gathering. They believe themselves the better, beautiful race and in this light purge the rest of the races which they call eyeblights. [Answer] **To be the last one standing/A whole lotta power** Eventually the god will come back to check on them and create more (otherwise they'd die off given a long enough time frame no matter what). When the god does come back to create more, whatever tribe or individual is left standing will be the de facto ruler of the new members and will become immensely powerful, regardless of any favours or gifts given to them by the god. [Answer] We mostly meet warriors. Or at least former warriors. Whatever they do after a few hundred years it's time to move on to something else, but whatever else they do having been a warrior leaves a lasting impression. She may look like a fishmonger now, but she learned that knifework with a sword. They could have a general draft, or consider war a part of a well rounded education to further enforce this. When you are good at fighting it always seems like a solution to the current problem. It might even turn out to be the best long term solution if word gets around that they are good enough at it. People who have not trained to fight often find people who have unexpectedly aggressive, because they either skip the normal preliminaries of intimidation or successfully use intimidation, winning the fight without fighting. Conversely if one of these people wants to live a quiet life they would probably get pretty good at that too, and no one would ever hear about it. [Answer] Perhaps the 'gods' have a simple sustainable lifestyle goals. The 'elvish' kingdom can sustain 12756 'elves' and no more are made if the numbers do not decrease or the kingdom does not increase. War will solve either constraint problem, either more conquered lands or less 'elves' the 'gods' will have to return and make more 'elves' like they always have in the past. ]

[Question] [ It's a few years in the future and society in general is fed up with hoarders; people who have a lot of money lying around that they don't use. Motivated by the rule that money should roll, they overhaul the (by now fully digital) money-system and add these new rules: * Any money you obtain has a 1 year lifetime. * If you have not spent that money after 1 year, it will simply vanish from the system. * The system is a simple "first in/first out" queue, so if you earn 100 [money] today, that means you need to spend at least 100 [money] in the coming year, or it will start going away * Simple loopholes are closed. You can't trade money for money. Buying something and then later selling it back to the same guy means the money returns with a shorter timer; if you bought something 4 months ago and then sell it back to the same person today, you will get money with an 8-month timer on it. * Your bank account has a timer on it that shows when and how much of your money will go away, so it won't suddenly vanish. * The rule *only* applies to money, never to goods. This includes goods with only artificial value. However; the buyback rule still applies; if you buy an artificial good and then sell it back to the same entity more than a year later, the money will vanish immediately. * The rule applies to both people and institutions. That includes pensions and insurance companies. Due to the stack system, it should be possible to maintain an effective savings-account of roughly one years' income. But anything beyond that is impossible. What would happen to society and the economy under these added rules? How does this impact regular people and how does it impact the super rich? Assume that "people move somewhere else" is not an option as the system will be implemented globally. [Answer] This move replicates the [effects of very high inflation](http://www.tutor2u.net/economics/reference/inflation-consequences-of-inflation). Money is still a medium of exchange but no longer a good store of value. There is one small respect in which this system is less harmful than inflation: at least the rate of loss of value is predictable. People's savings are wiped out. With the loss of business confidence, no long term projects can be embarked upon. People demand both to pay and receive1 money upfront when anything is sold, including labour, so wages and prices rise, probably adding real and unpredictable inflation to the artificial steady inflation of the currency scheme. Lenders lose badly. Existing borrowers gain by being able to (in fact, more or less forced to) pay off their mortgages and so on. Those wanting to borrow *now*, however, cannot do so since no one will lend to them. You do not state whether "pots" of money held by banks and other institutions from which pensions are paid would be subject to the same rules. If they are, pensions become worthless. Hoarding of physical goods, for barter as well as for personal use, replaces hoarding of money. This disproportionately impacts the poor, who have not got the money to buy in bulk, the space to store in bulk, or the security to keep safe whatever officially or unofficially takes the place of money. If I recall correctly Hugo Chávez once floated a proposal to replace the Venezuelan currency with some sort of coupon that would expire after a few months, but it was never enacted. --- 1 *Added later after second thoughts:* It is obvious why an employer or purchaser would want to pay someone quickly - the whole idea of the system is to make money "radioactive". At first sight you might think that the employee or seller would benefit from having their payment deferred, effectively forcing someone else to hold the money for them in a system where holding money is penalised. However I think there would also be another effect in the opposite direction which might dominate. The new system would mean that everyone's held money was decreasing in value at a rate which was *highly irregular* and *known only to them* (because it follows the exact pattern in which they had earned money a year ago). Everyone would have their own personal inflation rate. I think that the general effect would be that *all* money loses value and that all long term transactions would be discouraged, because of the unpredictability. If that effect dominates, better take your money now. After all, there would still be many circumstances in which it was better to have money in the bank than not! But I must admit thinking through all the ramifications is making my head spin, so I might be wrong. [Answer] If it vanishes when not spent, then it's not money. Money is: * A medium of exchange * A unit of account * A store of value If it vanishes when it's not spent, then it's not a store of value, and so it's not money. What happens in a society without money is that people invent money. [Answer] Funnily enough, this was already done. Prior to the transition of Fiat Currencies, a common form of currency in the dark/middle ages was Grain Receipts. Farmers would deposit their grain in a silo, get a series of receipts and then exchange them for goods & services, and the recipients of those receipts could exchange them again for grain. Being grain, it does go bad over time, so the receipts were dated and could "go bad" and become worthless. However, this limited the influence of nobility, who couldn't really use grain receipts to fill coffers or have taxes, so the creation of the feudal states also came alongside the introduction of currency based on precious metals... something the nobles had in abundance. The impact of the two systems were very different. While a fiat currency would be accepted everywhere in a certain realm, Grain Dollars were highly localized based on the location of the grain storage silos, and while they could potentially be traded further away, there was a risk for anyone receiving that currency that the amount of grain would be worthless if they waited to long to retrieve. This created a very diverse economies that were segregated from each other, still operating on a bartering principle for people passing through, or going between townships. Because there was no single bank in the middle, each township would rise or fall depending on their own behest, not the influence of outsiders, nor were there much by way of faceless syndicates controlling things because everything is hyperlocalized. Some differences to our economy: Savings are only good for hard assets - Stocks could still function, but bonds would not. Real estate, education and heirlooms would be more powerful as investment vehicles. Pensions would be replaced by things like REITs, CMOs, and profitsharing/dividend investments. Credit would be de-emphasized or be in a different execution than what we have now. If you would like to do some research on systems such as this, you can look at the [Ithaca Hour](https://en.wikipedia.org/wiki/Ithaca_Hours), an existing hyperlocal currency, as well as research on the ancient Jewish economy, which was based on 7-year cycles where all debts were cancelled, and all lands were returned to their original owners. [Answer] **Nothing Much** The problem is that these rules have an impact that would be hard to detect in our economy. For example: * Any money you obtain has a 1 year lifetime. Oh no! My money is loosing its value after a year of no transactions. Luckily... I don't actually have that much money - my main asserts are my property and the debt the bank owes me (in return for my deposit)... but not actual money. The only 'money' that could lose in value would be my coin collection (which's value is not tied into face value) and notes lost in the couch - not relevant in a system that is *fully digital*. But how do banks store value you ask? Well beyond trading debts/credits a bank could invest in assets - which is entirely permissible: * The rule only applies to money, never to goods. This includes goods with only artificial value. However; the buyback rule still applies; if you buy an artificial good and then sell it back to the same entity more than a year later, the money will vanish immediately. I do note that you add the rule of not selling back to the same entity... but in a market (like the fish market, gold market, stock market, or pretty much any market) you'd expect there to be a plethora of buyers and sellers, so this would be a non-issue. The small risk of collision could be handled by banks. Again, this is what banks do already today - they invest money in assets (e.g. my neighbors house) so they don't have to keep 'money' sitting around. ***In summary, rather than an arbitrary 1 year rule, banks today are concerned with the far more real losses of having money sitting around doing nothing! As such they've developed systems to solve this problem and we use them every day without thinking!*** [Answer] Such forms of money have existed in the past. But the money isn't destroyed, just 'taxed'. It is called a [demurrage currency](https://en.wikipedia.org/wiki/Demurrage_(currency)). The ancient Egyptians used such a system with grain deposits. The demurrage was used to pay for loss from rats, for the granary guards, etc. Middle Ages Europe had a system where the local lord would demand everyone turn in their silver coins for new silver coins, minus a 20% 'fee'. This usually happened once every two years or so. The value of older coins not redeemed would automatically lose 20% of their value. And [Silvio Gesell](https://en.wikipedia.org/wiki/Silvio_Gesell) invented a system of stamp currency that worked very well in the two instances it was tried in a German town and an Austrian one back during the Great Depression. In both cases, you had to buy stamps to keep the value of your script from devaluing over time. The stamps were sold by the organization that issued the script in the first place. Unstamped notes of course were calculated as being worth less. Today, a local complementary demurrage currency in Bavaria called the [Chiemgauer](https://en.wikipedia.org/wiki/Chiemgauer) is in use. And in Canada, there's the [Salt Spring Dollar](http://www.saltspringdollars.com). In all cases, such a currency enjoys high velocity rates. That is, the rate of exchange over time. Higher currency velocity means more trade is going on. People had an incentive to unload the currency... especially before it reduced in value than they do with regular currencies. So, a lot of investment in hard assets happened -- land, artwork, productivity enhancements, etc. People also donated more money for long term projects like the building of the great cathedrals in Europe. Employment levels are generally higher too. And taxes are paid earlier as well. All of which died down when the kings took control of currency system in collusion with bankers to institute the debt-based currencies we know today or when the Romans did the same to the Egyptians. For the two towns in Germany/Austria they were a tremendous success. So much so that the central bank of Austria panicked and declared the currency to be illegal in the case of the Austrian town [Wörgl](http://reinventingmoney.com/worgl). [Answer] Your idea is just a tax on non-use and is not new. In many countries with scaling tax systems, receiving taxable cash is bad, because you could be taxed up to 90% if it is income or you hold it as taxable income for a tax year. That's actually worse than your vanishing cash idea. Therefore, you either immediately transform it into something "protected" or in a lower tax bracket. Example: In the US from WWII up until about the 1980s - much of the money owned by the rich was tied up in assets only taxed when profit is taken. When the tax structure was changed, the durable goods were translated back into cash and cash began to flow back through the economy. Therefore, in your world, people would immediately translate cash into something durable that would not suffer the non-use tax. People would own more "things" rather than cash, and those things would be valuable and tradable. This would probably lead to more crime because forcing people to physically hold their reserves (i.e. life savings) makes every house a very juicy target. It would also inflate the value of whatever durable good was used in the place of the vanishing cash. This would cause inflation on that durable good. It would slow the movement of money, slowing innovation, commerce and your economies. Lastly, unlike a real tax, where the money eventually does wind up back in the economy, in yours you are removing people's work from the economy. To really wildly speculate, if it gets out of control - people can't trade it for something durable to hold on to for the future (like to feed themselves if they lose their jobs) - you may see your population growing desperate and fearful of the future - combined with the likely increased in crime, one possible outcome is rioting and possible revolution **--or--** the rise of a fascist state or slave system that promises people future food in return for current work. [Answer] I can't see it changing much besides maybe banks having a bit more power. The way I see it, banks would offer plans where they *move around* your money. They buy good for you with your money from another bank (or any entity), who will sell them to somebody else through another bank, and so on. [Answer] That form of money will not be used. Even though you state that it is not allowed, it would still happen. The free market would create another form of currency. This may be illegal, but people would want a item that could hold its value so they would still do it. The creators of the currency would have different responses to this: they could ignore it which could lead to more people using other money, or they could harshly respond with force which would scare others into using the 1 year currency. Either way though, it likely at least a few people would use a new currency to allow their money to exist. [Answer] Actually, a form of this is currently in use. Government agencies and company departments are given a budget, usually for a year. One form that this budgeting takes is that if you don't spend it all, then you obviously don't need so much in your budget for the next year. You don't get to save any of one year's budget for the next year, and if you don't spend it all, your budget may be reduced for the next year. So there is no incentive to *not* spend every last cent. On a more personal note, you would work until you drop dead, because there would be no way to save up for retirement. [Answer] Here is an actual currency with a value that deliberately loses value. Chiemgauer : A German regional currency 1 Chiemgauer = 1 Euro When you purchase a Chiemgauer, 3 cents goes to a charity of the purchaser's choice and 2 cents goes to the issuing organization. The Chiemgauer is only valid currency within the Rosenheim region, so they keep the money local. Every 3 months the Chiemgauer certificates (it is a strictly paper currency) expire and whoever is holding the certificate at that time must pay a 2% fee to reactive the certificate. The Chiemgauer apparently circulates at a rate 2.5x that of the Euro. You may convert the Chiemgauer to a Euro and receive 95 cents, which encourages a business paid in Chiemgauers to spend them on local suppliers rather than converting them and spending the money elsewhere. [Answer] I would say that most people would not approve of this and switch to another system. They would buy things of real worth, for example, gold. Then maybe they'd make their own currency (which is legal in the US) and base it off this. Other people might just go back to bartering for things. I don't think this is a realistic scenario, though. What about the millions of people who save up for retirement? [Answer] People will turn the money into more permanent forms and find other ways around it. > > Buying something and then later selling it back to the same guy means the money returns with a shorter timer; if you bought something 4 months ago and then sell it back to the same person today, you will get money with an 8-month timer on it. > > > OK, so you can't buy and sell between two people. What about three? B buys from A and sells to C twelve months later. C sells back to A another twelve months later. Perhaps you can never sell anything to someone who has previously owned it -- ever. So you are constantly selling forward. After one hundred fifty sales, you have entirely new people from the beginning. Not a big problem in a world with seven billion people. It's also unclear to me what happens when you buy securities like stocks or bonds. Are these money that expires? Or goods? If goods, then I guess this adds an extra level of complexity to trading. You can't sell to the immediate previous owner under the original rules. So you'd have to track that for every security. If securities are money that expires then you could never hold long term. You'd have to sell your shares annually and buy different ones (possibly from the same company). Of course, unless you own enough shares that you eventually run out and have to switch to a more diversified portfolio. I think that "banks" or whatever replaces them would find ways to handle this for you. You'd invest your money. They'd handle making it persist. Eventually, someone would point out that the whole system is just a waste of time and end it. Then things would become more like they are now. [Answer] A Polish friend told me how Poles got around the currency problems in the Soviet Union; they were not allowed to own more than x amount of money. Poles are not dumb, so they would share it out among family members, and get it back as needed. So would your system notice if the same dollars were being passed around? Are they tagged somehow? It might be quite legitimate for family members to give each other money for whatever reason. Anyway the nephew might give his uncle not the same dollars the uncle gave him, but ones he got from his auntie. So a clever family could keep up a merry-go-round of cash and never lose any. Whatever rules you make, they will be surmountable. [Answer] Whatever currency operated by these rules would not be long for the world. People invest and trade in the normal course of their lives. One of the principal roles of money in an economy is as a store of value (medium of exchange and comparative index being the other two.) Businesses like Amazon required a great deal of startup capital and were not profitable for the first few years. The need for durable capital will not disappear, therefore the market will invent other ways of storing value that will not involve this perishable currency which will quickly fall into disuse. [Answer] It looks cool, but one year is a very short period. I mean, I need from three- up to five years to put away enough money to get a loan for buying a flat. Would that mean, in your system I would live my life in a rent? Also - I think - there should be a lower limit of the money disappearance. I mean like statue artists typically can't sell their works very often, in your system they would starve to death. Edit: Oh, and I forgot about banking. What can you do about banks moving money around and paying an interest rate higher than the disappearance rate? [Answer] A properly implemented [demurrage](https://en.wikipedia.org/wiki/Demurrage_%28currency%29)-based system would lead to a vast increase in consumption. After all, unspent money loses value, so we need to spend *now* and not tomorrow. As others have pointed out, that is exactly what happens with the [Chiemgauer](https://en.wikipedia.org/wiki/Chiemgauer). An improperly implemented system would change nothing at all, as people would find ways around it (indeed, your bank does not hold your money, it just holds a promise to issue you money when you ask). This too has been pointed out by others. [Answer] Companies and high worth individuals, governments and other institutions rarely keep large amounts of cash - they usually invest or if they know they'll need it, they put it in liquid short term bonds (assuming money market accounts are same as cash and subject to expiration rules). Yields on those short term loans will fall, resulting in very low borrowing costs. There will be a big incentive to invest in real estate and durable goods - anything that you can store value in. Oil, coal, heavy equipment (airplanes, ships etc), buildings, metal will see initial price hikes. With low borrowing costs and high prices for durable goods there will be a big incentive to build more buildings, extract more natural resources, invest in intellectual property etc, etc. Regular people who don't have much savings will not be affected that much but might be forced to rent due to the high real estate prices. [Answer] You could actually do this with bitcoin. When a bitcoin is transferred, the sender ID, receiver ID, and the time the transaction took place is all logged to the ever-growing block-chain. If the bitcoin community decided to implement a new rule - that a coin which remains in the possession of a single owner for over a year cannot be traded - this could take effect immediately, right now, in our actual world. And I can foresee at least two interesting outcomes: 1) Bitcoins that are due to expire have their value diminished to less and less until it expires. I could buy other people's coins for less than 100th of its value if its just about to expire, because I know they either sell it or lose it. I have leverage. Conversely, "fresh" coins have the maximum relative value. This situation wouldn't just create an environment where commerce is encouraged - it creates an environment where wealth is *generated* by commerce. In a trade, worthless money becomes valuable money. In fact the amount of money is essentially irrelevant. 1 fresh coin is worth a lot more than 100 soon-to-expire coins. You bank balance would not be a number, because the amount doesn't really matter. What matters is how long until your last coin is purged. It would be a histogram of expiration dates. Reminds me somewhat of the Justin Timberlake movie "In Time". 2) Money is destroyed, so it must also be created to prevent all the money running out. In bitcoin we have miners who make money at a given rate. Assuming the government created money at a given rate, it still has to give that money to someone. For bitcoin its the miners. If we lived in a world where bitcoins could expire, the miners who scored the freshest coins would become the richest by a long, long margin. ]

[Question] [ In a world very similar to ours, rain has a high concentration of simple carbohydrates in it, enough to sustain life on the surface. After some rainfall, this sugary rainwater is left behind and some organisms consume it while it's still dissolved. Other organisms wait for the water to evaporate and leave behind a crust of nearly pure sugar that can then be consumed. Fungi, animals, and microbes all live on the surface of the world, but there are no photosynthesizers found on the surface and all energy comes from the sky in the form of these sugary raindrops. The concentration of sugar in the rain can vary dramatically, from nearly-pure to saturated. The world is very similar to ours, but atmosphere density and composition can be variable. I'd like to keep the $O\_2$ concentration at about 20% to maintain Earthlike lifeforms. Sunlight intensity and temperature are both open to variation as well. Such a sugar should be produced by natural means- there's no god or intelligent being sprinkling sugar on the planet from the outside. **What could cause rain to have a high concentration of simple carbohydrates?** [Answer] The rain is actually the blood of billions. A species on a nearby planet is being harvested by a technologically advanced alien civilization and the specimens are drained of all their internal fluids and then the filtered fluid with only the sugars are deposited onto your planet. The specimens themselves are made into powder to be consumed by other aliens as aphrodisiacs. The price of the drug is high so they want to harvest as much as possible with as little weight as possible. The reason they throw the stuff on your planet is that there are alien laws that prevent dumping of waste in open space and your planet is the nearest to easily dump it on. [Answer] Your world has much more of an airborne ecosystem than Earth, including a large number of floating photosynthetic aeroplankton. These little plants float about turning sunlight into sugar and are collected in the clouds when water starts condensing. These water droplet collect the air-algae and fall, carrying their carbohydrates to the surface. You are going to need some mechanism whereby they can't survive on the surface, otherwise they would colonize and you'd have normal plants. My first thought is constant cloud cover so no light, but you could also make them utilize some exotic chemistry existing only in higher altitude air. [Answer] # How to build an airborne ecosystem I will admit to plagiarising Josh King's airborne ecosystem. However, in my defense, the sugars have to either come from air or from space, so any answer has to incorporate those factors. I will explore how a plant could be made to have an airborne ecosystem, but not one of the ground. ### To not have plants, you can't have sunlight To not have sunlight, you must either a. be very, very far from a star or b. you must have heavy cloud cover. Turns out, you can do both together. Venus has a series of high clouds made of sulfuric acid. These clouds cover the planet completely and are opaque to most forms of radiation. Despite being closer to the sun, the optimal light energy received on the [surface of Venus](https://en.wikipedia.org/wiki/Atmosphere_of_Venus#Clouds) is around 10,000. Meanwhile, direct sunlight on Earth is about [100,000 lux](https://en.wikipedia.org/wiki/Lux). Spacecraft that have landed on Venus are unable to make use of solar panels for energy, due to the low light conditions. In order to create sulfuric acid, sulfur dioxide (from volcanos), oxygen and water are required. Since you wish to have a 20% oxygen atmosphere, this could work out well. There is no reason to have a majority carbon dioxide atmosphere as Venus does, a nitrogen/oxygen atmosphere with sulfuric acid clouds will work well. However, there is a requirement to have a high atmospheric density for the sulfuric acid to float. Sulfuric acid haze exists above the 10 atm layer in Venus' atmosphere. If the pressure were lower than this, the sulfuric acid would collect on the ground from rain. Instead, sulfuric acid rain evaporates in the atmosphere at around 25km altitude and is recirculated. In order to have max cloud cover, the atmosphere must be well over 10 atm at ground level to ensure that minimal sulfuric acid rain pools on the ground. ### Thick atmosphere can mean greenhouse effect Depending on your atmospheric composition. If your atmosphere is primarily nitrogen/oxygen, the greenhouse effect will not be that significant. If it is carbon dioxide/oxygen it will be very significant. This will only affect the distance from the star of your planet. With a nitrogen/oxygen atmosphere, your planet will need to be closer to the sun than the Earth. Due to the high albedo of the sulfur dioxide clouds, most solar energy will be reflected back into space. Venus, for example, receives less solar energy than the Earth, despite being closer, since so much is reflected. ### Cloudtop organisms will need to process sulfur compounds Sulfur-reducing bacteria exist on Earth; they convert sulfate ion (SO$\_4^{2-}$) to hydrogen sulfide (H$\_2$S). Sulfate ion will be available from sulfuric acid in solution in water droplets. Anywhere water droplets can float, these bacteria could find their food. Here, an oxygen atmosphere is an advantage since it will recycle the hydrogen sulfide to water and sulfur dioxide, and the sulfur dioxide will further react with molecular oxygen and water to produce sulfuric acid. ### Oxygen requires photosynthesis In order to maintain this oxygen atmosphere, you will need a metabolic process creating oxygen. The only one I can think of that will work is photosynthesis. This is the weakest link in this ecology, in my mind. The photosynthesizers will need to float *above* the sulfuric acid clouds in order to get sufficient sunlight. An alternative would be a photosynthesizer that uses [long wave infrared](https://www.astrobio.net/alien-life/infrared-photosynthesis-a-potential-power-source-for-alien-life-in-sunless-places/) light. This light could penetrate the clouds and mean that there would be some low-level photosynthesis happening on the planet's surface (a second food source, beyond the sugar rain). This needn't be too much biological mass, but it has to have been happening long enough to give the planet (with an active geological cycle to keep sulfur in the atmosphere) a 20% oxygen atmosphere. # Conclusions You will need: * Sulfuric acid clouds to block sunlight * High-density atmosphere to keep sulfuric acid off the surface. As a bonus, this makes larger organisms able to float in the clouds (think [salps](https://en.wikipedia.org/wiki/Salp)) * To get a 20% oxygen atmosphere, you need either a nitrogen or carbon dioxide base. A nitrogen planet would be nearer the sun, CO$\_2$ farther away to account for the greenhouse effect. * You need at least trace amounts of water to allow sulfuric acid formation * You need a sulfur source to keep sulfuric acid in the atmosphere. Volcanos are the usual culprit. * You need a photosynthesizer, possibly floating or at ground level using long wave infrared light to produce oxygen. Of course, with all this, there isn't really sugar raining down from the sky; its more like dead bacteria. So you won't end up with a Candyland sugar-crust, but you would end up with plenty of fungus food on the surface, and I'd imagine the fungus could be the base of a complex animal food chain. You could add some handwavium reason that either a. the sky bacteria just drop sugar for funsies or b. some sky amoeba-like predator eats bacteria and poops down sugar. But given how valuable sugar is as an energy source, neither of those explanations seems reasonable to me. [Answer] There is a chemical reaction (actually several reactions that all occur together) called the [formose reaction](https://en.wikipedia.org/wiki/Formose_reaction) that can produce sugars from formaldehyde. It is thought that this reaction might have occurred on the early Earth and played an important role in the origin of life. There might be a way to have the sugars produced by the formose reaction on your planet. The main difficulty is in coming up with a plausible source of formaldehyde. [This paper](http://www.chtf.stuba.sk/~szolcsanyi/education/files/Chemia%20heterocyklickych%20zlucenin/Prednaska%207/Doplnkove%20studijne%20materialy/Formose%20reaction/The%20prebiotic%20geochemistry%20of%20formaldehyde_Review.pdf) says it can be produced from carbon dioxide and water under UV light, i.e. in the upper atmosphere. Presumably the main reasons this doesn't happen on Earth are the ozone layer, and the fact that having lots of oxygen in the atmosphere means that formaldehyde will rapidly be oxidised. I don't know for sure, but it might be possible that if your atmosphere is 20% oxygen and 80% CO2, and has plenty of water vapour, then you might be able to produce formaldehyde at a high enough rate that it won't all be oxidised. Then you could have sugars formed by the formose reaction inside water droplets in the atmosphere, which explains the sugary rain. The variability of sugar concentration would easily be explained by the fact that the formose reaction is quite slow and quite sensitively dependent on conditions, so the amount of sugar would depend quite strongly on how long the raindrops had been in the air, among other things. Some caveats are in order though. If you don't want photosynthesisers on your planet then oxygen is a bit of an issue. Although the reaction that produces formaldehyde from CO2 also produces oxygen, that oxygen will be used up by the metabolisms of the organisms that consume the sugars. You would need an additional, extra source of oxygen in order to maintain an excess. (Though as Richard Tingle points out in the comments, this could happen if some of the organic matter doesn't get metabolised back into CO2 and instead gets buried and subducted, leaving an excess of O2. This is exactly how it works on Earth.) Secondly, formaldehyde itself is quite poisonous to most (all?) organisms because it's quite reactive, and it's used as a disinfectant for that reason. The sugars from the formose reaction are also poisonous to humans, but I would not be surprised if some organisms can eat them. Similarly, an atmosphere with 80% CO2 would be lethal to most (all?) Earth animals, though plants and some microbes would be fine. So this planet's life might be somewhat Earth-like, but it would be adapted to this particular environment and most Earth life would not survive there. Another caveat is that the formose reaction is catalysed by metal ions, which means your rain would either have to be salty (it's hard to imagine how that could happen) or there would have to be some other catalyst available in your atmosphere. Finally, formaldehyde is not very stable in the presence of oxygen - pure formaldehyde is a flammable gas - so it's quite hard to imagine that formaldehyde and oxygen could co-exist in the same atmosphere. Overall, I don't think this scenario is particularly realistic or likely, but it might be just about in the bounds of possibility, and I couldn't resist putting it forward given the specifics of what you were asking for. [Answer] *We already havy sugary rain on earth.* We have several species of plant louses. Many of them are specialized to suck on trees, especially on conifers, but also on leaf-bearing trees. They are digesting proteins, but cannot use all the sugar they get with the blood of the trees. They loose aromatic sugar drops at their very back end, falling down to earth. Also, ants and bees collect these sugar drops from the louses. Beekeepers call this honeydew, it gives a rare, expensive and aromatic honey. This honeydew falls down from the trees like a thin sweet rain. Did you ever touched something in the summer that feels stickily, your car, or a chair in the garden? I bet it was under a tree, covered with a thin layer of honeydew. I imagine giant trees reaching up to the sky with their branches and leaves in the sun, above an everlasting cloud that inhibits photosynthesis on the ground. Myriads of louses drop sweet manna sugary rain. [Answer] Sugar is produced by plants to attract pollinators (e.g. insects or hummingbirds or their analogues). It's also in the sap of plants (see e.g. "sugar maples"), and leaks whenever the plant is injured (see e.g. woodpeckers, see also e.g. sticky sap which leaks from evergreens). Sugar can be fine (see icing sugar), even very fine. When it's no longer needed (e.g. after pollination), or unwillingly by force (e.g. because of regular hurricanes) the sugar is carried off by the wind. It's then carried in the atmosphere until rain drop condense on it, just like rain condenses on other types of dust on [this planet](https://physics.stackexchange.com/q/273710/3773). [Disclaimer: I'm not a scientist ... this answer is only meant to be superficially plausible.] [Answer] Liquid Sugar geysers, that spew the sugary liquid high into the atmosphere. The origin of the geysers could be animal plant etc. Sugar volcanoes sound fun too. [Answer] Ok, so no "probably-intoxicated-higher-power sprinkling sugar on the planet", but how about "probably-intoxicated-higher-power-engineered natural solution"? As in, it's plausibly self sustaining but stupidly improbable to have occurred naturally. See, the issue I have with the idea of an airborne ecosystem is that they're fairly inhospitable to live near and/or improbable in any coherent evolutionary chain. It would have to evolve on the surface, have a strong enough selection factor to result in a sustainable airborne population by natural selection, but some how not be killed off by the selection factor before becoming airborne. It's kinda like the logic of a species of birds that evolved to never land *because* doing so results in instant death, the only way such a species could exist would be from avian paranoia. Wait, getting off track. My solution is explicitly improbable. I call it the living weather balloon strategy. Essentially you engineer a suitable photosynthesise strain that can do something like $CH\_4 + H\_2O + 2CO\_2 + light => C\_{3}H\_{6}O\_{3} + O\_2$ then you wrap that around a sack of helium (See note 1), such that it has a neutral buoyancy somewhere near the top of your cloud layer, and figure out some handy way of making the things basically immortal. I figure any species that can bio-engineer an enzyme process that turns methane in to glyceraldehyde (given that they're kinda nothing alike) should be able to engineer a sufficiently robust host. They'd excrete (actually perspire is probably more accurate?) the sugar on their surface and it would get washed away by the same clouds that provide the water for the process. Once you have a small army of these things, you release them in to the target atmosphere and leave for a while. They'll have fun turning two annoying greenhouse gases in to useful byproducts, exactly the sort of things you'd want to do if you were, say, terraforming a planet over the long haul. Obviously you're not going to wait around while your sweet (pun intended) beach balls clean up the atmosphere, maybe you stick a calendar reminder to pop back later and don't bother. So long as they're reasonably robust the losses due to damage should be negligible, the concentration of sugar in the rain would be proportional to methane concentration in the area and frequency of rain. Oh and did I mention the neat alien planet vibe from the rafts of FLYING BALLOON WEED?! Like for real, how many planets do you come across with plants drifting through the clouds, probably casting greenish shadows when they pass in front of the sun? This is why I said probably intoxicated... you need a particularly odd frame of mind to fly around the galaxy dumping these things all over the place for giggles. Note 1: I specified helium primarily because it side steps some tricky issues. You *could* actually use hydrogen instead as a lighter than air gas, maybe extracted from water. I would worry that sacks of hydrogen might be more vulnerable to damage (read: horribly unproductive combustion) though. The upshot though is that you could probably figure out a mechanism for them to reproduce via division or something, since the helium is a limiter for that, but that's a whole mess of more implausible stuff that I'll leave to someone else's imagination. To be fair, a hydrogen filled version does have a tiny possibility of evolving naturally, it's just babel fish levels of improbable and a finite improbability generator would be only slightly less intoxicated engineering than my proposal. [Answer] You have flowers that release aerosolized sugar spores, rather than pollen. The rain simply encourages the plants to bloom. The plants derive their energy from bacterial processing similar to tube worms. [Answer] Your planet is located in a star system which contains a [cloud of orbiting sugars](https://news.nationalgeographic.com/news/2012/08/120829-sugar-space-planets-science-life/), and interaction between the planet and the cloud mean that sugar is periodically deposited into the upper atmosphere, where it is slowly absorbed by atmospheric water and eventually rains down onto the surface. ]

[Question] [ There's a valid discussion about feminism and objectification of women to be had. This is not the place for it, nor do I attempt to make it one. I noticed that in Fire Emblem: Fates (and probably other games and media, but I couldn't name any off-hand), several of the female characters have the seat of their pants exposed, though it depends on their class (combat role), which can be changed. This is not the case for male characters, who can take on virtually all of the same classes and still be fully clothed. For example, female [archers](http://fireemblem.wikia.com/wiki/Archer) and [sages](http://fireemblem.wikia.com/wiki/Sage) are fully decent. Female [cavaliers](http://fireemblem.wikia.com/wiki/Cavalier) and [knights](http://fireemblem.wikia.com/wiki/Knight) are not. This question is not about why the illustrators design the characters this way. My question is this: **Is there anything resembling an advantage to having the sun shine on your seat (while being otherwise armored) in a fantasy-setting battle? If so, how would your combat role and sex affect these benefits?** [Answer] Hmm... in a culture that equates femininity with cowardice (regardless of whether the females actually *are* more cowardly than the males), it could be a way to get them to fight to the death, instead of retreating. After all, if your front is covered but your back isn't, you're going to want to keep your front to your enemies so they can't exploit your armour's built-in weakpoint. This sounds misogynist, but it's entirely possible that a given world's military leaders could actually think like that. It could be contrasted with other cultures or military leaders in the same world, who give everyone the same armour, to make the audience dislike the leader(s) responsible for the ass-baring armour; it'd actually be kinda interesting to see a mild culture clash about armour. If this is done, males in that military should be given normal armour, and talk made of females being able to "earn" the standard male armour based on their combat records. This could easily be able to say a *lot* about a culture. The first thing that comes to mind, for example, is that they recently started a shift from being heavily patriarchal towards gender equality, and a lot of their leaders still have the culture's old mindset. It could also indicate that they still *are* patriarchal, but willing to use talented fighters regardless of gender. I imagine such a culture would also push female combatants towards support roles (mages, healers, recon, etc.), which they would likely feel are better suited to women. [There could also be the more sinister implication that this culture considers female warriors more expendable than male warriors. This could be used to justify a female protagonist or antagonist defecting to the opposing side, once they realise this.] --- Alternatively, if females are more inclined to magic, giving them more exposing armour might imply that [armour interferes with magic](http://tvtropes.org/pmwiki/pmwiki.php/Main/ArmorAndMagicDontMix). Since the average female combatant in this world would be either a [mage](http://tvtropes.org/pmwiki/pmwiki.php/Main/SquishyWizard) (including [healers](http://tvtropes.org/pmwiki/pmwiki.php/Main/WhiteMage)) or a [magic swordswoman](http://tvtropes.org/pmwiki/pmwiki.php/Main/MagicKnight) (including [combat medics](http://tvtropes.org/pmwiki/pmwiki.php/Main/CombatMedic)), female armour would logically contain as little actual *armour* as was necessary to protect the wearer; female combatants would likely wear either robes or cloth armour (for pure mages), or light armour designed to only cover essential areas (for magic swordswomen). There's also the possibility that [casting magic requires a lot of motion](http://tvtropes.org/pmwiki/pmwiki.php/Main/FullContactMagic), or [may also be a martial artist](http://tvtropes.org/pmwiki/pmwiki.php/Main/KungFuWizard), either of which would warrant lighter, less-restricting armour. Alternatively, the solution may be as mundane as most female warriors using defensive magic to protect themselves, rendering armour redundant (in which case only minimal armour would be worn, as a backup in case the warrior ran out of MP). If this is the situation, it would be interesting to see how this affects purely physical female combatants. Would a female combatant that can't use magic still get the same armour as her more magically-inclined counterparts, or would she get something more akin to normal armour? If the former, how would this disadvantage her, if at all? If the latter, would she have to take up a slower, less mobile combat style than she's used to? --- And, of course, a third elephant-in-the-room possibility is that the armour's in-universe designer is a pervert, and has a thing for ladies in exposing armour. If this is the in-universe reason, it would most likely be played for laughs. [Answer] Most authors and artists claim that practically nude armor on women has two advantages: 1. It makes her faster and less encumbered. 2. It distracts male soldiers. But this is a stupid argument, in reality neither of these will work or have any practical effect and there is no benefit to the so called bare ass-armor [Answer] In a matriarchal society it might very well be, that a womans body is a symbol of power and so it's common for women to show it off (think of it as a equivalent of a men wearing sleeveless clothes to show off his muscles). This would lead to a "priviledge of nudity" in different grades, depending on the importance of this custom. If it is important enough, it might even be that it would be incorporated while designing armor or uniforms. [Answer] It would make no sense at all. The point of armour is to *protect* and bondage chic hardly does that. There's materials that flatter *and* protect but generally the typical fantasy female armour is designed for looks rather than practicality. You'd get bitten in the ass by bugs, get wedgies in combat. Sometimes people shit due to stress, so the sexiness factor is overrated.Splinters and thorns happen in the wild, and imagine having to pull out thorns from your own buttcheeks. Hell *sitting down* might end up being a ordeal, especially in the hot sun - Ever burnt your feet barefoot? Blisters?. Also sepsis. Puss coming out of random body parts is unsexy. I can't think of any purpose outside embarassment, punishment, and looking good on the cover of a magazine or book aimed at teenagers who think with ... the wrong part of the body. Others have talked about distraction (but clothes can cover *and* flatter) and unencumbered movement (which you can do with more practical clothes). There's a reason that most military uniforms, no matter how flashy tend to revolve around *comfort* and *protection*. If you want a sexy uniform, hire a fashion designer, and *make them wear it everywhere for a week in the field*. If you're a petty medieval despot, stuff like this is *exactly* what encourages your harem to kill you in your sleep. [Answer] A quote from Words of Radiance > > “So yes, I, Adolin Kholin—cousin to the king, heir to the Kholin princedom—**have shat myself in my Shardplate**. Three times, all on purpose.” He downed the rest of his wine. “You are a very strange woman.” > > > This is a real thing. If you are battling for hours, you are pushed to extremes. No time to drink water, eat snacks, or poop. Exposing the rear end makes mid-battle poop a breeze! [Answer] If you look like a sex kitten I'll underestimate you giving you the chance to tear my throat out. If you're hot a lot of the blood rushes out of my thinking equipment into... other equipment. Rendering me stupid and predictable. If I'm looking at your tits I'm not looking at the point of your sword, allowing you to thrust said point though my eye. As I'm winding up for the killing strike I might take a moment to peek up your skirt granting you the half second you need to put an armored boot on my throat. (which is also kinda hot, by the way) Oh and I think the Kurds are sending women into combat because ISIS thinks if you get killed by a woman you don't go to whatever magical warrior heaven they all want. Don't quote me on that, I heard it on the internet. These are all stupid reasons though. You gotta cover up or people will poke holes in your skin. [Answer] A quite simple but reasonable example might be tropic, Mediterranean or at least in any aspects hot climate. Consider amazons, for example: in such a culture, there's no problem with a lot of exposed skin. In general, in these settings, it needs for comfort. --- Also consider **agility**: certain clothings decrease the speed of moving legs. Of course, certain military units are not heavily relying on it, but if you want to create agile and quick units (ninja/assassin/scout archetypes are the most obvious IMHO), then you may gain advantage from it. I mean, whatever you wear below the waist, that might be beneficial is it's tight, because it's harder to tear down, and might provide effective protection, compared to some loose dress. However, it also slows you down because it can constrict you, by obvious reason. Try running with huge steps in jeans. --- These were my main considerations while exploring the topic; of course, society is also a defining factor in it. Certain cultures (such as the "general European culture and mentality", if I can define such) find exposed thighs and buttocks (**especially** buttocks) suggestive and strongly attractive. Okay, some may argue about it but at the very least, one's for sure in general: in said cultures, people are always paying attention to it, rather than finding it "natural". If this pressure is present, then exposed bottom won't (or less likely will) be present, especially among war-related workers (=fighters/warrior/soldiers/etc) --- This is why I started my answer with hot climate. Exposed skin is less of a "taboo" in these cultures. In ancient Egypt, for instance, women often left their breasts exposed - and it's still not uncommon in jungle tribal civilizations. It's, on the other hand, less likely e.g. in Europe. --- TL;DR - to justify exposed bottom, three main considerations can be taken: climate, agility and society. Also notice that two of these make it possible, if not naturally expected for men to have less clothing below the waist. Of course, if males and females are equal in this question, then the latter has no significant advantage from it. --- In the end, however, it's kind of an instinct in males to be pleased by the view of female buttocks. I'd suggest trying to explore this very simple fact, if you want significant advantages for females. [Answer] Well, this is a refreshingly fun take on the gender-so-very-not-neutral combat fashion issue :-) We can't help but note, however, that the OP seems to be asking whether there are any combat advantages to exposing the buttocks **specifically**...and if so, why that advantage might accrue solely to women. 'james turner' is the only one so far to make a good case for a genuine buttocks advantage (i.e., "...magical mounted women. in which case, perhaps armor interferes with their magical bond to their steed.") Sadly, I must counter that the saddle itself, in that case, would interfere just as much, and for magical mounted men and women alike. And if one eliminates the saddle, any gain in magical bonding is likely nullified by loss of concentration owing to ensuing pain. There's some pretty severe chafing in the future of those who combine bareback riding and bareass armor. Our research indicates 'james turner' is nonetheless on the right track in positing a magic-related rationale, as there IS a theoretically plausible, gender-specific combat advantage which might compel an open-ended design in female armor. In numerous species of primate, a change in female buttocks color is an indicator of an actual underlying biological change. Note this hormally-induced alteration does not typically occur in the male of the species. In a world where magic is a reality, it is more than possible that hormonal changes would produce quite different physiological effects, alterations in external coloration among them. In addition, given the complexity of human intelligence and emotion, a noticeable different in buttocks hue might signal more than one meaning depending on mental state, physiological stress, and external conditions. Ergo, while in peacetime the reddening of a woman's buttocks might denote fertility or sexual arousal (*as is common in many Earth primates*), in a time of war, when men and women become partners in combat rather than reproduction, hormonal changes fueled by magic and adrenalin may alter both its genesis and significance. Add to this that women may well be more sensitive than men to the nearness of a threat, since in peacetime they are the primary and fiercest protectors of their young. Consequently, during wartime, the sudden switch to bright red buttocks becomes an indication not of approaching fecundity but approaching **danger**. Clearly, women would then leave their buttocks bare as an early warning system for their comrades. For during combat the reddening of the female rear no longer beckons, "come hither," but flashes a sudden crimson signal of, "Beware! Danger Approaching!" The male rear, on the other hand, signals nothing, and so is covered to prevent confusion, as well as to protect the more sensitive bits of reproductive equipment needed by a post-war society to replenish its population. [We have recently submitted a fuller explication of our theory for peer review by the Journal of Magical and Cellular Biology, and will be happy to provide any interested commenters a copy of the final article upon publication.] [Answer] Berserkers: Subbies may be on to something, but I think we can take this further: I have an army of men who can send their adrenal glands into overdrive. They can fight through wounds that should kill them 6 times over. They have the strength of ten bears and the reflexes of a stalking cat. They can see more clearly, aim more truly, and think more quickly than any possible enemy. There's a problem, though. That costs a lot of energy. I need a way to trigger them at the right time so that my enemies can't leave my troops exhausted by the time the fighting starts. I need to be able to hold some in reserve, so that a small ambush doesn't set off my whole battalion. Enter the warrior priestesses. They have magically altered pheromones which simply expand upon the natural link between adrenaline and the three F's. They have been trained not only to fight, but also to turn on their troops at just the right moment. A small cadre accompanies each unit of berserkers, divided such that several women can set off selected members. I key my troops to these women by means of a small magical item, say a fetish. I just have to make sure that I have the right women near the right men. No one woman can crank up the whole army, but no group is bound to a single priestess's scent. The priestesses have magical defenses, as stated elsewhere, so real armor isn't an issue. The goddesses these women serve (collectively known as the Ladies of Night) are are associated with both fertility and war. They are generally depicted in rather immodest attire. Facing enemies nearly nude (as the goddess would) is a sacrament to Viagras: Tender of Fields Fertilized By the Blood of her Enemies, Ciali: Who Waters the Fields and Drowns the Wicked, and Levitras: Who Guides New Souls to the Womb and Purges the Impure. That means that restricting airflow to or visibility of these women's nether regions hinders both the dispersal of pheromones and the ability to manifest the power of their chosen goddess to trigger their compatriots' fetishes. To sum up: if an idea is so patently ludicrous that "because magic" isn't enough to justify it, you may need to add a dash of religion. [Answer] In the Doctor Who universe, the [Sontarans](https://en.wikipedia.org/wiki/Sontaran) are known for never retreating. This is because the weak spot in their armor is behind them. So long as they face the enemy, they are invulnerable. If they were to turn their backs, it exposes the weak point in the back of their necks. From that perspective, exposed buttocks would make sense so long as the armor in front was good. In general, there is a tradeoff between armor/clothing being protective and easy to move in. The more comprehensive the armor, the less agile the warrior wearing it. Obviously most warriors seem to prefer armor to agility, but perhaps some are in different circumstances. It's not just female warriors. Schwarzenegger's Conan the Barbarian wore primitive shorts into battle a lot of the time. Similarly, Superman and Spiderman both wear form-fitting tights. Armor is mainly good in melee combat. If you are inside a structure and shooting missiles (arrows, bolts, etc.), the structure is your armor. You may prefer unencumbered legs for maximum mobility. [Answer] **taunting** it seems common for [soldiers to expose their butt](https://en.wikipedia.org/wiki/Mooning#Notable_incidents_of_mooning) or genitals prior to a battle as a way of taunting the enemy (e.g. [the pissing champion of meereen](https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwil6eqaoYDPAhXHJcAKHYPvDMkQyCkIIDAA&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D3_xLwn-btlU&usg=AFQjCNF3GBlhWb44EsXGT-xf9ktgmjzP3A&sig2=wboyMbfJGUEaf2fpMpje9Q)). if this tradition became so common as to be expected, then you might have soldiers simply leaving their butt exposed as a show of bravery (cf. [the red barron](https://en.wikipedia.org/wiki/Manfred_von_Richthofen#Flying_Circus) painting a bright red target on his plane). [Answer] **They operate like the Landsknecht** In real history, we do have the example of the ancient Greek Hoplites. They became so proficient in the use of the Hoplon (hence the name) shield that they did away with any other armor (and even clothes) except on their legs and head in order to maximize mobility. They could get away with this because the Hoplites were extremely well trained for years to work together as a unit and each man would cover the one next to him as they moved as a team. So, given the real history of basically naked warriors, we can extrapolate some things about a society that puts female warriors in metal bikinis. The Hoplites did NOT armor the parts of their body covered by the shield. These females do not cover their butts and thighs (usually). That implies that there is some other form of protection available to them in combat. Obviously, since they usually don't carry massive shields, but some other parts of their bodies ARE covered in pretty good armor, the protection must come from a combination of weapon and body position. This makes me think of Pikemen. The revolution of firearms was preceded by a very similar revolution thanks to the perfection of the pike by the Swiss and others during the late Medieval period. Pikemen could do away with armor because the pike itself would keep enemies at a considerable distance, making shorter melee weapons useless. Developing a considerable esprit de corps, the pikemen would don very flashy cloth uniforms. The "landsknecht" developed as these specialized warriors showed off how brave they were by wading into battle with basically no armor at all. The thing that kept them alive was the pike itself and the fact that they moved as a very close block of men (somewhat like the Hoplites) and worked together to form a "hedge" of pikes. What these two historical examples have in common is that they were infantry units who worked closely together in tight formations and protected one another. They were specialized, and used long weapons to keep enemies away (spears and pikes). Neither unit was the fastest on the field, but both would form an impassible wall of men that could block off an enemy force and could be decisive in a battle. Here is why the women wear metal bikinis: They don't run as fast as men (this is a physiological fact) nor can they carry as much weight (again: biology, not my opinion, that is why there are male and female Olympic events). Culturally, these women come from a class of priestess-warrior types (I'd imagine something like a Buddhist monastery where it would be common for unmarried youths to spend a certain amount of time dedicating themselves to religious ideals before moving on to start a family or whatever). Like a Greek Gymnasium, they spend a lot of time training together, so they can operate as a tightly-knit unit of women. Since women are not as fast or strong as the men, in battle, their position has become standardized as a "blocking force" -a slower moving phalanx that stays together and at a critical moment forms a wall of spears to block in the enemy and force them to come to battle at the right place, while the men move around to flank them or attack from the rear. The way this works is the women will march together in tight formation like a Greek Phalanx and when they get to the right spot, they will kneel like the pikemen, their armored shins protecting their mostly naked stomachs, their armored forearms protecting their chests, and their spears forcing the enemy to stay at a distance. This creates a bristling wall of spikes that can stop a cavalry charge if executed properly. As with Hoplites and Pikemen, it is considered extremely brave to stand and face the enemy this way (for obvious reasons), so, like the Landsknecht, female armor types have become increasingly showy and decorative to show how little they need their armor, and to rub in the faces of everyone that these virgin monk-warrior women are untouchable but desirable. Properly employed, a phalanx of metal bikini-wearing warrior women can stop an enemy force in it's tracks, allowing the men to flank and rout them. [Answer] Perhaps the advantage of this sort of armor is not aimed to the women wearing it, but to their male companions. I mean, image yourself as one of them. You're preparing to fight your enemies alongside these sexy female knights wearing what sometimes amounts to a chain-mail bikini, you get hot and bothered by the sight of their splendidly toned backsides. Your heart starts to race, adrenaline and testosterone start pumping into your blood due to your sexual frustration. Triggered by these primal animalistic urges, and thrown into battle, you will fight harder and more aggressively to relieve this pent up desire and prove subconsciously that YOU are the alpha male around these parts. If you were a commander, wouldn't you want a unit of heavily armored, sexually frustrated, aggressive young males to set upon the enemy? [Answer] The bare-bottomed female warriors are being driven into combat by *Enforcers*. The Enforcers, hand selected for their cruelty and courage in battle, wield long bull whips which they use to sting the exposed buttocks of any hesitant warriors. [Answer] Seduction. If you desire something it controls you. A female warrior doesn't rely only on a single skill set to best her enemy. Male physical strength is offset by female charms. Female always charms the group she's in often having alpha male of the group acting as a protector. I'd say dressing seductively is a necessity, in a group of bland looking fighters the weakest one is the first to go. ]

[Question] [ Let's say I invented a [perpetuum mobile](https://en.wikipedia.org/wiki/Perpetual_motion). For real! A wheel spins, or a voltage is provided across two metal prongs, whatever, without it requiring any fuel or input of energy. Maybe it uses some not yet discovered law of physics, maybe it taps into some parallel universe, whatever. My problem is that I would like to use the official way to introduce a new discovery to the scientific community, but I fear that if I just wrote a paper and sent it to a few journals, they would just toss it into the garbage. There are far to many quacks (actually, all of them, except for me), there are far too many youtube videos and patent applications with fakes, so that all serious people are bored with finding the hidden power source of the machines brought to them by claimants, that now they probably dismiss all claims outright. I would like to introduce it to the scientific community. Although I would be happy if it gave at least some profit to me, I don't wish to become a multi-billionaire while limiting its use to maximize profits. I want the global community to make use of it, so I fear if I just founded a company, I might get tricked or attacked by people with more power and experience, so my invention might end up rotting in some company's (or government's) basement or might be patented so that no one will be able to use it. The device is too large and bulky to power a car, its power-to-weight ratio is terrible (not much better than a steam engine, but hey, it at least doesn't require any fuel), but that might be improved upon in the future. In its current form, it is not exactly profitable, for the costs it took me to build it, it would need a *lot of time* to return its investment in electricity bills. Lot of time means that it has a slightly worse cost-to-build versus power-it-provides ratio than solar cells, but it doesn't require sunshine, works at constant capacity, and it might be improved in the future. It's not built quite out of household materials, so it needs some fairly good electronics, rare materials, but all can be bought on the open market (no rare material only produced in scientific facilities). It took me quite a lot of time, effort, and expenses. I stumbled onto the principles almost by accident, it is advanced enough that the layman will certainly not be able to build it at home, but a well-equipped university lab might be able to reproduce it given enough time. They, however, might not want to invest the many tens of thousands of dollars for materials, and many thousands of man-hours to do it, just to "disprove yet another crackpot theory", unless I manage to convince them. The device is complex enough that just by reading the description nobody will say "aha, I now see that it will work". No one will be convinced unless they really reproduce it, and they must be really careful in it, avoiding many pitfalls. I don't want that a small mistake in the reproduction makes it non-operative and so they dismiss my claim. They have to really give a lot of effort and dedication into reproducing it. Although having an academic background, I don't work at academia, and don't have a team of researchers under my command. Trying to get back into academia and reach such a status would take too many years and might not even work. If i just contact my ex-professors or fellow ex-students, they will probably laugh it off and not take it seriously. This is important, as I'm not known in the scientific community, and my experience in writing good papers and finding good journals is limited to a few insignificant ones as undergrad. Even if a university lab does try it and does succeed with it, they still have to convince the larger community. So, how can I publish it for the benefit of the scientific community, while not giving up authorship? I don't want to build an empire onto it, but it would be nice if I wouldn't starve if I lost my job. [Answer] Let's get one thing clear about science. Nothing is off limits. We don't have sacred cows. We don't worship our calculators. Newton is not a god. If you somehow break the laws of thermodynamics, honestly, for real, reproducibly, then all you have to do is let someone play with it. If you fear being dismissed if you make outrageous claims too soon simply temper them down. Ask us, "How does this work?" If we can't explain it, and you can, and we can reproduce it, without your interference, you've just started a new field of science. Nobel prize time. It may turn out you only thought you broke the law of thermodynamics, but actually discovered a new source of power. Still Nobel prize time. If you want an example of how this might play out in the real world. Read up on [cold fusion](https://en.wikipedia.org/wiki/Cold_fusion) (a failure) and [high-temperature superconductivity](https://en.wikipedia.org/wiki/High-temperature_superconductivity) (a success). Neither was seriously predicted by theory. To us, fantastic claims only require one thing: fantastic proof. Doesn't matter who you are. Some may claim this isn't enough for scientists. Those aren't scientists. This is how science works. If you don't do it this way, it isn't science. [Answer] I propose: The [frog boiling principle](https://en.wikipedia.org/wiki/Boiling_frog). Let's assume your Perpetuum Mobile requires input energy to get started - you start spinning the wheel by hand, or heat its cauldron until the boiler gets going, or it needs a certain amount of watt hours and then starts generating electricity. When you passed that threshold, it just keeps going, and going, and going. You have, in short, built a machine that takes power as an input, and generates power as an output. If you didn't know the machine generates more output than input, there's nothing strange about this invention - it's just plain ol' [power storage](https://en.wikipedia.org/wiki/Energy_storage). Power storage isn't new, we've built dams to power water mills since I don't know when, for example. But even though it's old, it's also quite fashionable: We're using wind and sun to generate electricity, but we want our lamps shining on still nights; we're seeing some really awesome electric cars these days, and we don't want them plugged in while we're driving; etc. Now, let's assume that if you tap the energy your machine produces too heavily, it stops. Right? Great, because now you can craft some carefully skewed (but correct) test results that are scientifically uncontroversial but still very interesting. Suppose you can get 90% power efficiency if you drain the machine in one hour (i.e., input 10 kWh and you can pull out 9kWh in one hour), or 99% if you drain it in a day (9.9kWh from 10kWh), and increasingly better efficiency the slower the tapping. No need to say that you can tap 10.1kWh from the 10kWh of input if you do it over the course of a week, or infinite kWhs if you tap even slower, because the amounts of energy tapped under such circumstances are rather uninteresting when comparing production costs to power output (or whatever excuse you can make up for not testing the truly remarkable cases). The stage is set for you to patent your Very Efficient Power Storage, not saying that it is actually also Yet Another Perpetuum Mobile. Finding some clever scientists who are interested in improving on this remarkable - but still quite plausible according to accepted theory - design shouldn't be that hard if builds upon pre-existing designs into which there is currently being put scientific effort to improve. If it is a completely novel design, unlike anything ever seen before, it'll probably be harder to find suitable academics since they'll pretty much have to leave their entire previous research behind (but who knows, perhaps there's a brilliant scientist out there who wants something new to sink their teeth into, or someone who just realized their current research subject is a dead end?). With a suitable staff, you can get venture capital, and from the efficiency improvements your white-coated pals find, you can build a successful company and make big bucks from selling your Very Efficient Power Storage to grid owners, electric car manufacturers, or whatever suitable customers you can think up. As more and more research effort is put into your design, some strange, wonderful, and frightening results will surface in your lab. Your staff - academically distinguished, of course, and probably still connected to prestigious universities - can't believe their own results. But it *actually happened* - we achieved 150% efficiency! They won't mention it outside the lab, but since you keep an eye on things, you notice it and let them in on the secret. You lab continuously produces papers detailing the advances you've made. Your findings are very interesting and prestigious journals on the subject of power storage (I assume there are such journals) happily publish you. But your papers never really delve into the truly strange parts, the efficiency on low outtakes. If someone took the time and money to build a device like yours, they'd notice... but they probably wouldn't believe their own findings. That doesn't matter, though, because it's actually quite expensive and complicated to reproduce and it is trivial to see that your designs *actually work*, and the science in your papers seems to add up just fine. As your invention becomes commonplace, you gradually improve its efficiency. At one point, when the scientific community are feeling fairly comfortable with the improved design's 99.999% efficiency during a one-hour draining, you launch a new product line that has >100% efficiency. Perhaps you won't even say anything, and noone notices anything unless they're crunching numbers on electricity production vs consumption. Perhaps you'll start your own power plant generating electricity from nothing. One day, you make the statement, and noone will want to believe you but they have to since you now run a large-scale production facility of free energy, which incidentally also powered the coffe makers of the people who call you a fraud. The frog is now boiled. You are free to share your invention and patents with the world, if you like. [Answer] Before you do anything else, leave no doubt that the invention is yours. Take many redundant measures so that you can't be sued out of your discovery. Next, you have to show the larger sciencific community that your invention works. As you pointed out, it's very unlikely that you will be able to instantly convince a large chunk of the sciencific community, especially since you are not known. So you either have to change the "instant" part or the "large chunk" part. Since waiting too long isn't an option, you will have to start out by convincing just one sciencist. Look for a professor or researcher who works in a field that is related most closely to your technology. Offer him x ammount of money per hour (up to a limit of y hours) to look at your blueprints, and offer a reward of $10,000 if he/she finds the power source. Encourage him/her to invite friends as well, and double the bounty. Once you have this sciencist (and maybe a few of his/her sciencist friends) convinced, offer them a share of the future monetary benefits you will get once the invention is recognized. These can include prizes, a prestigeous research position under you, or a company you will build (even if you decide that this machine or a company in this field won't be profitable, your characters don't have know that; they will probably think it will make them rich). These sciencists will get some of their friends to verify the invention as well (for free, because they know/trust each other). Offer these new people a share of the company too. This proccess of sciencists asking their friends can continue. Once you have a resonable numbers of sciencists on your side, you can stop offering shares of your future company; sciencists will pay attention to it for free because it will gain some credibility. At some point, you can send your findings to a journal with a large number of sciencists backing you (make sure you are the author) and you can reap the monetary benefits (nobel prize, professorship, grants, etc.) [Answer] Well, you nailed it pretty hard. Yes, any attempt to use or demonstrate a "perpetuum mobile" would be futile, this ground is too poisoned. I do not think any attempt to communicate with scientists will be fruitful (I am a scientist and I would be extremely sceptical and dismissive myself). The whole thing reminds me of [the Orbo of Steorn](https://en.wikipedia.org/wiki/Steorn). It is has a terrible power ratio, it **must** be improved. It must be useful for at least some applications. So if you cannot do it yourself, you need someone who has the technical background to improve the design. Or you try it yourself by trial and error. Once you have a working design, you patent it. And now you are flying under the radar *by adding a credible power source* and market it as such. So the customers get a functioning device and the scientific world is calmed. The very best thing would be that you use it for a scientific instrument. Well, sooner or later someone realizes...well, the battery should be empty now. But it still runs. Hey, the battery *is* empty. What ? Is that a joke ? It runs and runs. Where is the power source ? Now people will ask questions. You are completely innocent and simply tell them: What are you talking about ? It runs itself and produces more energy than it consumes ? *You* thought that it is impossible. Now scientists are curious and at least some of them want to solve the puzzle of the hidden power source. Just as training. First they are astonished, then they won't believe their eyes and finally they are aghast. Well, there you have it. The scientists are introduced now. ADDITION: After the glowing ode on science in some other answers I must put it in a more realistic view. Policemen are not in general the incorruptible, generous good person holding up law and order. Doctors are not in general the selfless professional who sacrifice their free time to save human lifes. Neither are scientists in general cold and undetached seekers of the truth. @Benubird: Are you actually aware that your sentence "and given that they rejected it, it sounds like they were actually real scientists" sounds a bit like *if they accepted it* you would think they are a bunch of shills and crackpots ? Confirmation bias is not a only a crackpot problem, it is human. I already said in the comment to CandiedOrange's answer that I will give counterexamples of professional behavior. After we got better and better telescopes, it was finally accepted in the 1920s that the former "nebulas" are galaxies like our Milky Way. Fritz Zwicky examined the Coma Galaxy Cluster and was irritated: Something was wrong with the rotation. The galaxy rotated too fast, you need gravitation to hold a galaxy together and *there were simply not enough stars* to account for the necessary gravitation. So he proposed "dark matter", something which does not emit light, but has gravitational influence. The "Dark Matter" theory gained finally more and more influence in the 70s. 70s ? What happened in the meantime ? Well, the astronomic community *chose to ignore completely* the problem. It was not the problem that they could not reproduce or prove it, a simple look through the telescope would have been enough. It was easier to sweep the problem 40 years under the rug. Unbelievable ? I challenge here anyone to show me that a scientific discussion in papers took place which took the phenomenon seriously. Another not so bright moment: Irving Langmuir had written 1953 a scientific paper about ["Pathological Science"](http://www.cs.princeton.edu/~ken/Langmuir/langmuir.htm), endeavours in science which were in his own words "the science of things that aren't so". In one example he criticized the "mitogenetic rays" of Alexander Gurwitsch 30 years earlier. Quite ironically: "The mitogenetic rays" of pathologic science [*do actually exist*](https://en.wikipedia.org/wiki/Biophoton), so it really may be asked why a valid result could be labeled as "pathological science"... Then the neutrino affair: The problem was not the measurement error. The problem was that while anyone which would come up with superluminal theories a bit sooner have been considered a crackpot. Now in arxiv a whole swamp of papers published such theories without an eye blink *instead waiting for the final confirmation that the result is genuine*. No, the scientists were not suddenly open, they simply hoped for the jackpot and to hell with Einstein. I must add that there are also very good and nice scientific endeavours which are in the majority and quite readily accepted, I simply do not like this extremely rosy paint. In effect scientists are currently underpaid and overworked (yeah, yeah, says everyone, but it is really a problem, especially for postdocs), they have not much time to follow spurious leads. The competition to publish papers is so hard that in some fields amateurs cannot publish without being ignored (if they are accepted at all). Just my 2 cents. [Answer] It's going to be a long term project. Look at the timeline of the EM drive. <https://en.wikipedia.org/wiki/RF_resonant_cavity_thruster> Over a decade later and still most scientists would not touch it with a ten foot pole. Be able to provide prototypes, be persistant, and don't oversell it. If you don't know how it works, say so. Be prepared for not just scepticism, but instant dismissal. Ask some theoretical physicists to study this interesting device and let them find out that it is violating known physics. [Answer] A nitpick - a machine that is powered from *elsewhere* isn't a perpetual motion machine. You're merely demonstrating an alternate power supply. You'd be richer than God. A steam engine can be a powerful thing, by the way. Think "locomotive". In general, I'll take the opposite view of many - it would be easy to get it reviewed by scientists. You negotiate a price and **pay them in advance, in cash**, under the agreement they **must** publish the results of their reviews. You'd put it on a trailer and take it to them. You'd build it so they had unfettered access to all components. Bring a welder, so any support part could be cut and rewelded etc. Also supply mechanics to disassemble at the request of the reviewer. But expecting scientists to foot the bill to review the device... nope. Patent the hell out of it first. [Answer] Don't. Use it yourself to translate the unlimited energy into unlimited wealth and power. If it were actually real, some benevolent "scientific community" is not who's going to benefit from it anyway; powerful governments militaries would, and they'd have no qualms about screwing you over in the process. [Answer] As a claimed "perpetual motion machine", you basically can't get it accepted. The reason for this is that the second law of thermodynamics is the solidest law of nature we know. If your scenario actually involves breaking it, you need to lose the hard-science tag. A relevant quote, from Eddington: > > The law that entropy always increases, holds, I think, the supreme > position among the laws of Nature. If someone points out to you that > your pet theory of the universe is in disagreement with Maxwell's > equations — then so much the worse for Maxwell's equations. If it is > found to be contradicted by observation — well, these experimentalists > do bungle things sometimes. But if your theory is found to be against > the second law of thermodynamics I can give you no hope; there is > nothing for it but to collapse in deepest humiliation. > > > As "this is a way of extracting energy from (explanation that makes sense in physics terms)", it is an interesting discovery, and you might well be able to get a job with some company that wants to develop it. A way of presenting it if you don't know where the energy comes from, is to publish in the same way as the physicists who measured neutrino speeds [faster than light](https://en.wikipedia.org/wiki/Faster-than-light_neutrino_anomaly) in 2011: as something they could not explain, asking for help in explaining it. But whoever figures out where the energy comes from will get most of the credit. [Answer] It's all about your phrasing. Daring to contradict CandiedOrange, some things **are** off limits in science. Perhaps not in the ideal world, where everything is a point mass and all my cows as spherical, but in the real world, perpetual motion is a severe non-starter. Real flesh and blood scientists simply dismiss them without even hearing the argument. Far too many people have been swindled by false claims of perpetual motion. Some scientists might be willing to hear a theory about ghosts, but none are willing to touch perpetual motion. Accordingly, you're going to have to sell the story correctly. Sell yourself as a skeptic. When you publish, it should not be "hey guys, check out my perpetual motion machine," but rather, "hey, I'm noticing this funny error term that I can't cancel out... can somebody run these experiments and figure out what I did wrong?" Solicit advice on how to better constrain sources of error. **Sell it not as a perpetual motion machine, but as a problem for the scientific community to solve.** It's going to take time. You're literally going to have to shift the entire scientific community in a direction to take perpetual motion off the "off limits" list. That will take time. From your description, the amount of free energy generated is very small compared to the energy and materials that went into making the device. Accordingly, your device could simply be producing energy as the result of a decomposition of some of the material in the device (similar to the behavior of a [sacrificial anode](https://en.wikipedia.org/wiki/Galvanic_anode) in the [SALt lamp](http://www.digitaltrends.com/home/salt-lamp-alternative-lighting/), which claims to run on nothing but salt water). You may have to run your machine a great deal before you can gather enough samples to really start to leave scientists puzzled. Remember, the threshold for "discovery" of a subatomic particle that every expected to see was 99.9999% confidence. That's where the particle physics community puts their line these days. Discovery of something which fundamentally upsets every assumption ever made about physics in the past 200 years is going to require *substantial* confidence. You may not be able to constrain the experiment sufficiently in your lifetime to reach a sufficient confidence interval for such a earthshattering discovery. You may have better luck with the corporations. You may be able to convince them to find value in your invention, for one reason or another. Perhaps if everyone in the world is using the technology, you might find that the confidence in your theory is far greater. Science *loves* independent identically distributed samples, and having 7 billion of them would be a big step forward to moving perpetual motion from "we're not interested in discussing it" to "I wonder what's going on." > > It is a common misconception that the great discoveries in science are made in a brilliant stroke of genius which leads one to jump out of the bathtub and streak around town shouting "EUREKA! I have found it." That is not what true scientific discovery sounds likes. True scientific discovery does not sound like "Eureka," but rather "hmm... that's kind of funny." > > > [Answer] One thing that the tech and in particular gaming industry has shown me is that to file a patent you don't need to show a thing works, you just need a bad line drawing, an idea, and someone to write fifteen pages of indecipherable legalese. So, assuming the character could scrounge up enough money to hire a lawyer with some patent law experience, or perhaps have a friend who has such skills and is willing to help, simply have the file a patent **without using the words perpetual motion.** Don't take the engine and try to prove it works, just send an illustrated numbered rough drawing and a steaming mound of confusing words. Large scale circular impelling engine for usage in large scale slow repetitive rotary mechanical function systems. Or something. [Answer] I have serious issue with this question. You ask how do I get scientific community to accept my perpetuum mobile, but I see absolutely no reason why anyone, including yourself, would assume the device you describe is perpetuum mobile. A device that extracts work from some energy source we can't otherwise detect would be far more reasonable assumption. We even have some fairly obvious candidates for such source due to properties of dark matter. dark energy, and even vacuum being largely unknown. So since there is no reason to assume you have a perpetuum mobile, there is no reason to represent your invention as such, and no reason your invention would suffer due to prejudice against perpetuum mobile. Although to be honest, I think many scientists actually **like** perpetuum mobile and would be willing to spend some effort to study your work and find the reason your invention seems to work even if you claimed for some reason it is a perpetuum mobile. [Answer] Linus Torvalds decided that his work should be available and kept free to everyone (open source), whereas Bill Gates decided to make money from it. None of them starved and both of them are recognized world wide. If you want to make money you have two options: 1. keep it secret (like Coca-Cola) and pray for no one else figure it out; 2. get a patent (you reveal how you do it but you protect part of the market for you) If you decide to be make it public and free for everyone, then make sure: 1. you publish it as soon as possible (in any format: conference, exhibition, paper, video, post); 2. detail your work as much as possible so no one else would be able to patent what you didn't say about it; 3. enumerate as many variations and applications you can think about. By making it public, no one would be able to get a patent on it anymore. At last, keep in mind that by sharing your achievements and getting feedback from your work is a very rewarding experience. It can help you improve on what you've done and take you much faster to the next level. Good luck! [Answer] Write a history of your thoughts and construction of the device, dated honestly. Include as high-quality drawings as you are able. Have this notarized. Continue the dated diary and have it notarized on a schedule. Begin demonstrations. Invite schoolteachers, reporters, a Boy Scout troop, a service club, amateur science organizations (radio, aviation, seismologists) etc. and give demos until enough are persuaded. Sooner or later a working technological professional will be interested. Your notarized notebook will preserve your rights until patents are proper to acquire. [Answer] I think you're trying to base your story on a very flawed premise. That is, a person, without even being a scientist, makes several important inventions *(nothing wrong with it per se)*, discovers at least one completely new fundamental law of physics *(hmm, okay)*, but does not attempt to share, publish or use any of those in any way right until the point when he tightens the final screw and a perpetuum mobile device suddenly comes to life! Did he somehow know from the beginning that he will succeed in building that particular device? Did he just wake up one morning and started putting parts together until the device was ready? **Hollywood** A genius locks himself in a secluded laboratory and after 15 minutes of montage (which corresponds to something like 2~3 months of real time?) emerges with an Iron Man exoskeleton he built. By himself. Alone. From scratch. It's so ahead of time no one even understand how it's possible. It's so advanced no one can reproduce it even after extensive observation, studying and reverse-engineering. **Whereas in real life...** A genius, amply funded by different organizations, along with his many assistants, after decades of work, invents, maybe, several new materials, which can potentially be used to build an Iron Man exoskeleton, and also a somewhat new type of servo. As a team. Based on other people's existent research. Publishing like a hundred scientific papers every year, thoroughly explaining every minor achievement they make. The assistants not only understand the work enough to reproduce or continue researching without our genius - in fact, the genius already understands just a small part of the project. And the scientific community is more than ready to understand their next discovery, no matter how revolutionary. Back to the *flawed premise*. Contrary to Hollywood movies and novels of Jules Verne, no matter how ingenious you are, you can not achieve everything by yourself. Which leaves you with two possibilities regarding your hypothetical *perpetuum mobile*: It is already, by an large, accepted by the scientific community. or It doesn't exist. But if you want to go the Hollywood route, just add whatever *deus ex machina* to help your character, one more won't hurt... [Answer] I think the "best" way is by actually making money from the device. There are always copycats who will deconstruct and try and make a cheaper clone, so once they do, they will go to the scientists and say "how the heck does this thing work?". Voila, you have introduced to the scientific community while establishing the fact that you created the device. [Answer] # Invite Power Make the local power utility buy your electricity. Ideally, the machine would scale according to some input. That is, if you put more energy into the machine, even more power would come out. This would allow you to ramp up power output to any arbitrary level by introducing a feedback loop. Then connect your device to the local power grid, and charge the utility to buy your power (works in the USA). It really doesn't matter if feedback is available or not, as long as you can submit enough "free power" for the utility to meter it and notice. Even a few hundred watts of continuous power will be convincing. Dump power into the grid for a few months...enough to get statements from the utility showing that they are paying you. If you can get a feedback loop, great! You can easily dump enough power into the grid to put a nice dent in their profits, but be careful not to blow up your local substation!! Finally, write an open letter to the utility, along with properly redacted copies of your electricity bill, and have it posted as a full-page ad in the nearest big-city newspaper. Tell them that you are feeding power into their grid with a device that consumes no fuel, or that produces over-unity outputs (more power than it consumes). Invite them to come inspect your "generator" with qualified experts, under the condition that all inspections are conducted in full view of the media and independent witnesses, to prevent tampering/destruction. # Go National In fact, invite all national utilities, and threaten to bring your device to their grids too, if they don't come and investigate your power source. Especially invite the scientists (obviously). Ask the local universities to provide experts to oversee the inspections, and make it clear that you will comply with any reasonable requests to make the device available for testing (checking ground connections for surreptitious power, etc.). # Conclusion First, you are gathering evidence that your device does what it says. That's the electric bills. You are using an objective third-party to "pre-certify" your claim. Second, you are employing the carrot of curiosity, by inviting all experts to examine your device, and letting people know that you are aware of the kinds of tricks employed in the over-unity scam space, and that you will let them eliminate all such explanations for your device. Third, you are employing the stick of using your device as an economic weapon, by forcing utilities to buy so much power from you that they go bankrupt. This incentivizes them to quickly verify or disprove your claims, before things get out of hand. Of course, you could be just running a conventional gasoline generator and feeding it into the grid, as a publicity stunt; but the utility will eventually want to prove that is what you are doing. They might sit on their hands for a while to see if you get tired of buying gas for your generator, since you can't possibly do that at a profit; but the longer your machine runs, the more obvious it will be that it's legit, and you aren't just trying to scam them. And if you can introduce feedback, you can force them to act *very* quickly. With feedback, you can do something quite dramatic, like set up a huge Tesla coil and generate massive lightning displays powered by your device. When you get a forklift and pick up your device and drive it around a bit while the coil is discharging, it will become obvious that there is no way you are generating millions of volts and significant current from a scam device. [](https://i.stack.imgur.com/OaRrv.jpg) [Answer] > > ...for the costs it took me to build it, it would need a lot of time to return its investment in electricity bills... > > > Either 1) it produces more output than input or 2) it doesn't. It sounds to me like you put more into it than you can ever get out of it, and thus this isn't a perpetual motion machine. If it works for 100 years with no maintenance and still doesn't pay for itself, it's pointless to bring up to the scientific community. If it will pay for itself in 100 years, but requires maintenance along the way that negates the value, then it isn't perpetual motion. So you can be assured that if this is the case - that it will never produce more output than you put into it - then it will not be seen as a perpetual motion machine, and thus there is no good way to present it to the scientific community as such. [Answer] ## Despite hard-science tag * but topic is hot as hell, and I can not be silent Do you have plans? Put link to dropbox or any file share, I'll take look. 'll share profit with you, mail me. And yes, good move, about WBQ ;) I'll do same ;). How small it can be, can it be like tea pot - if yes, start kickstarter compain, more crazy ideas is, better it fires. Write: *Do you wish to be first owner of crazy machine which charges your phone, steampunk design, high capacity powerbank, fast charging rate* Equip it with real accums as buffer, as it constantly generates power it will look in some use cases like high capacity, in some cases as fast charging device. There are lot of technical channels on YT, they may review your craft, test it, even if they cant determine is it Impossible Device or not, they definitely may confirm some properties as they observe them. As example if [Applied Science](https://www.youtube.com/user/bkraz333) (have DIY Electron microscope which works actually good enough) will say it works this and this way - I'm sure that it work that way. There are lot of guys who are respectful, and they working on their channels for years and most important they do not seek or wait for such fat opportunity like this one to get some profit from, hm let say, easy impressed peoples. Say I'll like you to make review of this device, it have a bit of unusual properties, we call it advanced technologies, which I suggest it you to discover, overall it's just funny battery block. Some will do it for free, just for fun(because it's interesting content for their viewers). It will help peoples to know you, and your kickstarter complain, make some orders. You do not need much profit at start, and much orders - you just need crowd which may discover some interesting and most important useful aspects about device which will increase sales. If it's real deal it will make some cash flow for you, allowing to refine and scale production, improve device(if possible). If it can be portable, like under 1kg or less - it's excellent, it will be better then usual powerbank, and that's really enough to start sales. * I saw that note it's bigger and will not fit to car, but not sure you mean to produce appropriate enough power, for that car like 30kW or it's just some limitation of current construction. * I have to note that steam engine power/weight ration is't so bad, even for old machines. $\text{If it's big}$ If it's big that's will be harder, but also will depend how big. $\small \text{300kg, 1kW power, 3-10 times worse then steam}$ Once you have to prove that it will work for Х hours with 1kW power, and do not contain radioactive materials (just is save to produce and to operate). [Gasoline, Energy content](https://en.wikipedia.org/wiki/Gasoline#Energy_content) is 42.4 MJ/kg, so 300kg of gasoline is 3533 hours of electricity generation in case of 100% efficiency. Problem with scam is, they do not have working models, and they disguise that in any way possible. When you have working model, which already generates energy, instead of consuming it, there are ways to find funding, prove etc. And if result so measurable, it's easy to measure, steam power ratio it's not a 1mV$\times$1mkA per tonne of device, and it can work let say week nonstop. (in case of repair, any energy you may bring in your "pocket" will not cover 1week of continuous work with 1kW) There are lots of groups which would be interested even in that model as product. Survivalist's, crazy peoples, mobile operators, all who works on storage energy solutions, peoples in remote places, peoples who use diesel generator will be happy to replace just because of laziness to maintain and fuel that noisy thing they have atm. You may start your own broadcasting, specially while assembly of second device as example, and show everything, you will get some money just for doing that. Make patreon account. Will not say it's road without rocks but unique content is a key, even if it will be like: hey look, crazy dude makes spacetimemachine and shows that on the channel - this sure will bring attention, views, some cash. ## Nobel prize When you will have working samples and cash, you may just send them for testings, investigations.(probably it will be done earlier if you will work with companies) As result you will have working samples, and most importantly reproducible results. Working devices, is key to the situation, this is key difference from scam. I can name at least 10 peoples, some amount of small groups or places where to find them, and 3 companies(as I think, not sure, but there are some reasons why they will) - who may help and will be interested in such technology, even in it's current not perfect state - and that's a case, when it's not my field of interests. I'm even do not talk about opportunistic peoples, and I strongly recommend against partnership with them even in case you think you are smart enough. Again, with working device there is lot of options. If they will not get you a Nobel Prize in result, Mr. Alfred Nobel ... hm but that's different story, what he will do to them all. ## P.S. I noticed in some answers, people talk about small energy output, and such cases it's really hard to tell where energy comes from, and makes analysis difficult. I do not know if is that's OP mistake, or just peoples perception of demonstrated Impossible Device's, but I cite OP: * *its power-to-weight ratio is terrible (not much better than a steam engine ... )* [Here](http://5at.co.uk/index.php/definitions/terrms-and-definitions/power-to-weight-ratio-2.html) they show table for data from book *The Red Devil and Other Tales from the Age of Steam by David Wardale* , about Power-to-Weight Ratio for steam locomotives, lowest value for entry locomotive(as I understood) is **10kW/tonne** . Is that bad? Is that low? For free? You have kidding me, it's darn awesome. And definitely is ***easy measurable***. And no matter what it is called by inventor: cold fusion, nuclear reactor, Impossible Device, torsionic fields generator, or energy vampire, or wireless energy transfer, what ever - if it's mobile then **Anyone** with basic chemistry knowledge pretty fast may say is that Thing or not. In case it's mobile(important moment) If it can work 12 hours - it's a thing in any case, question is just which kind a Thing it is. Tesla(auto) weight around 2 tonnes and stores 85-90kW electricity. If that device may produce 120kW in 12 hours it is a Thing - it's or a good fuel element, or better capacity battery. If it can work few month continuously it's nuclear reactor or thermonuclear reactor or something else. In case reactors, it's very good power weight ratio, comparing to todays reactors. Or it may be something else, which have to be investigated, no matter how it is called by inventor. And to prove and show that it is a Thing, you need almost nothing, just make sure it's not connected to thermonuclear reactor in basement of his house. Almost no science needed at all. Understanding what happening is another deal, but convincing (in mobile version) that it's worth to investigate will take 24h. With such power ratio 100g device will be capable to charge 2 cell phones simultaneously, 2 iPod's etc. This just out the box use cases with huge market. Plot here will be if it robs some electric plant for MW each kW produced - but still it will be a thing, even better one then in all cases above. [Answer] You apparently lack the background to publish in the Scientific peer-reviewed literature. You also apparently lack the understanding of our patent system which would prevent you from failing to establish priority. That is, your main character seems so clueless (which is hard to understand if s/he really has put in the many months and years required to build and test such a device - what was s/he doing?! playing video games instead of researching the literature???) The USPTO requires a working model of any supposed perpetual motion machine. Filing your patent (and first getting (and paying for) a patent attorney) is step #1. It isn't clear to me why you want to build a huge device which won't even light a light bulb, costing thousands or millions of times as much as a life-time supply of flash lights. You're going to have to do better than break-even. Opportunity cost is the cost of one thing (materials and time to build your device, less the amount you can make from it) compared to the best alternative use of those materials AND your time. It sounds as if your pm device wouldn't be a rational use of your time, money, or mental energy. Assuming you and your patent attorney could schmooze your way into having an examiner look at it and assuming you constructed it in such a transparent way, that there were no "black box" sources of potential (hidden) energy, and that you convinced (bribed?) the examiner then the patent would be so enormously noteworthy, that fame and fortune would follow. Of course, unless you were very very very smart and canny, within months the big guys would file their own patents for nearly, but not quite, identical machines which would blow yours out of the market. ]

[Question] [ This creature exists in an infinite world, a flat landscape that extends ad infinitum, where light rains from the sky from infinity during recurrent day-night cycles, and, similarly, the ground goes down continuously. All kinds of critters populate the cosmos including the skies and the underground realm. This bizarre world has existed for an infinite time and for this reason I want (at least) one creature to have inhabited it for an infinite time. And that's not all, this particular being is also physically infinite(its body has no end); obviously I don't want it to take up all the space, but only a part of it. In the specific I was thinking of giving it a shape similar to something like [Gabriel's Horn](https://en.wikipedia.org/wiki/Gabriel%27s_Horn), so it would leave a large area available, however this would basically cut most of the surface in half, and on top of that most of his body is vulnerable to attack since it's so thin; for this reason I would like to avoid "infinitely small" bodies. What infinite shape can I give my organism so that it wouldn't be too vulnerable but at the same time leave room for people to move about relatively easily, without cutting off parts of the world that are close by from each other? Also, while its body is infinite it should have only one head. I am going to be a bit lax with the physics of this world to allow for some basic functionalities, but I want to put special attention to this aspect. EDIT: Thanks a lot to everyone for the inputs, I went with the answer that better fits the requirements, but I will probably incorporate elements from other interesting answers [Answer] The problem can be restated as follows: find an infinite plane non-intersecting curve which *does not* partition the plane. That's easy. Two immediate examples, described in polar coordinates: 1. $r = \exp(\frac{1}{0.01\theta + 1})$ (the red curve in the illustration), and 2. $r = 1+\left(1-\exp(-0.05\theta)\right)$ (the green curve in the illustration). [](https://www.flickr.com/photos/alexpanoiu/40962569544) *Two infinite yet bounded curves which do not partition the plane: r = exp (1/(0.01t + 1)) (show in red) and r = 1 + (1 - exp (-0.05t)) (show in green). Made with the [graphing calculator](https://www.desmos.com/calculator/xx9bymlu1v) at [Desmos](https://www.desmos.com/calculator/ms3eghkkgz). Own work, available on [Flickr](https://www.flickr.com/photos/alexpanoiu/40962569544) under the CC-BY license.* Converting the infinitely thin lines into lines with finite widths is left as an exercise. (Hint: make the width inversely proportional with $\theta$.) Note that the red curve grows inwards, and *r* will always be greater than 1, while the green curve grows outwards and *r* will always be less than 2. No matter how long the curves get they will never partition the plane in two disjunct regions. Also note that I'm taking "an infinite time" to mean "a really long time". Things become truly weird when infinite values are actually allowed. In particular, any event which is not impossible becomes necessary... [Answer] You specify "creature", but would a fungus fit your requirements? Taking inspiration from [Armillaria ostoyae](https://en.wikipedia.org/wiki/Armillaria_ostoyae), one example of which is the largest living organism, covering 3.4 square miles of the Malheur National Forest in Oregon (aka the Humongous Fungus). Despite its size, as it is a soil organism consisting largely of microscopic filaments interacting with plant roots it is mostly invisible, so even if it spread out over the whole world it would not get in the way. Its anatomy of largely self-sufficient parts would seem amenable to infinite scaling both in time and space. While this fungi is considered parasitic, it would be easy to imagine this being commensal or symbiotic with the plants of your world. [Answer] It might be infinitely tall, just like a tree (or giraffe) that simply doesn't end. Ever. A snake-like being would work also, provided that it either flies/floats/burrows or is flat enough that it is not a barrier to other terrestrial creatures. [Answer] There are some real-life species that do a decent impression of this already, namely [fungal mycelium](https://en.wikipedia.org/wiki/Mycelium) and [aspen forests](https://en.wikipedia.org/wiki/Pando_(tree)). Your criteria, as I understand them, are as follows: 1. Infinite spatial extent 2. Infinite age 3. Does not blanket the entire surface of the infinite world 4. Does not impede movement of humans over/under/through the space occupied by it too much 5. Is not particularly vulnerable to being chopped into pieces 6. Has exactly one head #3 and #4 can be addressed by having your creature exist mostly underground (or mostly in the air, but underground is easier), and #5 by having it take the form of a vast network. Like the aforementioned [fungi](https://en.wikipedia.org/wiki/Mycelium) and [aspens](https://en.wikipedia.org/wiki/Pando_(tree)). These organisms can survive large chunks of themselves being destroyed by virtue of having many more redundant parts all around. And in your case, if #1 is fulfilled, there is an infinite area of land infested with this organism. Any finite amount of destruction would barely be noticeable to the organism as a whole. #6 is probably the hardest criterion to fulfill. Any of the functions typically attributed to animal heads would be better served by a collection of nodes spread throughout the network, rather than a central node in one location. A singular mouth could never take in the infinitude of nutrients the organism would need to sustain itself. A singular brain could never respond to stimuli infinitely far away. If cutting off the head could kill the entire organism, it would never live to be infinitely old and fulfill #2. And if the world is flat and uniform, why should any one location have the head and not another? Perhaps the organism has a fractal network of nodes, each with its own brain. The smallest nodes directly control the organism's behaviors in a certain area. Larger nodes govern larger areas, delegating micromanaging those areas to the smaller nodes therein. Each node communicates with its neighbors and reports to the nearest node of the next size up. At each higher tier in the hierarchy, the number of nodes decreases, while the distance between them increases. In the limit, the infinity-th tier will contain one single node, infinitely far away from everything, which could be considered the "head". But for all practical purposes, it may as well not exist. Also, I should point out that an infinite space can contain multiple infinite, non-intersecting volumes. In fact, your first paragraph contains two: the sky, and the ground. Each is infinite in extent, but only takes up half of the space in your world. In fact, an infinitely long pipe running in a straight line across the ground has infinite volume, but only covers an infinitesimal fraction of the surface of an infinite world. Just because your creature has an infinite volume doesn't mean it has to take up the entire volume of the world. There can be plenty of space around it. **Update**: If you want something a bit more mobile than a plant or a fungus, you could have it grow various sensory organs (e.g. eyes) and prehensile limbs (e.g. tentacles) that respectively inform and are controlled by the nearest node. Which... could give it a seriously Cthulu-like appearance. If that's not quite the aesthetic you're going for, and you want it to be able to communicate with humans more easily, you could have it grow humanoid "avatar bodies" that are tethered to the main network for nutrition and communication with nearby nodes, but have their own brains and are able to act at least somewhat independently. [Answer] Could have a fractal outline and that would be an infinite surface within a finite volume. A Mandelbrot fractal looks as if it had a head (and a posterior as well) so that may serve your purpose. <https://en.wikipedia.org/wiki/Mandelbrot_set> Maybe this is not what you mean by infinite. [Answer] The first thing that came to my mind was an infinitely long giant centipede. It can be tall enough to let other things pass underneath it, but they would have to be weary of it's constantly moving legs. [Answer] Your creature is infinite and yet doesn't take up all the space in an infinite universe. Because you yourself specified that you want your creature to have a head, and therefore an end, I suggest that your particular creature is actually finite. Your creature is a mobius strip with some [mathematical knots](https://en.wikipedia.org/wiki/Knot_theory) added for good measure. Being a mobius strip design it goes on infinitely in a finite space. Over the lifespan of the universe, your finite creature can grow infinitely. You can have any number of these ancient creatures in your universe. Complexity to the creature design can be added with a combination of multiple knots. A mathematical knot is joined at both ends and cannot be undone. The simplest knot is a circle, or unknot. There are many different complex knots and new ones are still being calculated (similar to values of pi). I like to think of a Mobius strip as *essentially* a twisted unknot, although I do knot now if this would hold up to mathematical scrutiny. Some fractals can actually be considered ["wild knots"](http://mathartfun.com/FractalKnots/Introduction.html). A particularly complex knotted area can act as your creature's head, brain and any other limbs you may wish. Your MobiusBody doesn't even have to be solid plane but can be holey, allowing other creatures to travel through without breaking the creature up into separate pieces. To allow the creature to defend itself, it can move the complex KnotHead around the MobiusBody. I've attached an image with the first number of knots, I leave the rest up to your imagination. [](https://i.stack.imgur.com/JbkWQ.jpg) source: <https://www.shapeways.com/product/8A7NG95NH/mobius-strip-voronoi-5-frac12-in> [](https://i.stack.imgur.com/hxCHU.jpg) source: <http://irma.math.unistra.fr/~loday/Noeuds_table.jpg> [Answer] **Immanent being.** <https://en.wikipedia.org/wiki/Immanence> > > Immanence refers to those philosophical and metaphysical theories of > divine presence in which the divine encompasses or is manifested in > the material world. > > > This is a trippy concept. If you want a big snake that is infinitely long, or has infinite number of teeth this will not work. But your world already deals with the infinite. An infinite being would occupy the entirety of it. Immanence is a good companion concept for what is shaping up to be high concept fantasy. Usually immanence is considered in the context of God - a conception of God is that God exists throughout the entirety of creation; not transcending creation but occupying creation. There is no reason your creature could not be like this. It exists throughout the entirety of what is. It is not the same as the world but it is inexorably intertwined with it. You might or might not be able to sneak up on such a being. It is everywhere at once, but a cat can sneak up on my foot and I might not notice. You might or might not be able to attack such a being. An attack cannot drive it out of a place that it occupies because that is impossible; infinite-1 = infinite. But it might change the character of the being that occupies that place. You might be able to kill such a being. The death of it will probably change the world it occupies. Remember: he's a god; it will take more than one shot. [Answer] This world could be filled with fractal critters. They can be as large or as small as you want, as they just have infinite detail: the closer you get to the critter, to more of it you can see. Perhaps [Menger sponges](https://en.wikipedia.org/wiki/Menger_sponge) inhabit the oceans? They can be made into [some cool carpets](https://en.wikipedia.org/wiki/Sierpinski_carpet). Or perhaps mollusks with [Apollonian gasket](https://en.wikipedia.org/wiki/Apollonian_gasket) shells? An [Ikeda map](https://en.wikipedia.org/wiki/Ikeda_map) jellyfish? [Mandelbrot](https://en.wikipedia.org/wiki/Mandelbrot_set) manta rays? I know you only asked for critters, but why stop there? An infinite world could also have fields of [Mandelbulb](https://en.wikipedia.org/wiki/Mandelbulb) flowers, crops of true [Romanesco broccoli](https://en.wikipedia.org/wiki/Romanesco_broccoli), [Dragon](https://en.wikipedia.org/wiki/Dragon_curve) island chains, caves with [Sierpinski](https://en.wikipedia.org/wiki/Sierpinski_triangle#Analogues_in_higher_dimensions) stalagmites, [Pythagoras trees](https://en.wikipedia.org/wiki/Pythagoras_tree_(fractal)), and storms of [Lichtenberg](https://en.wikipedia.org/wiki/Lichtenberg_figure) lightening and [Koch snowflakes](https://en.wikipedia.org/wiki/Koch_snowflake). The [options](https://en.wikipedia.org/wiki/List_of_fractals_by_Hausdorff_dimension) are, by defnition, endless! [Answer] **A mist or vapor** Asking for the shape of an infinite body that isn't infinite is somewhat... *definite.* So we're trying to get as close to infinite as we can. The problem, of course, is that the body gets in the way of every other body in the world. What would be the difference between such a creature and a ring of impassible mountains restricting access to the rest of the infinite world, making the world definite? After all, you're going to encounter this creature quite literally 99.99% of the time, so one hopes it has legs so you can walk beneath it... but then there'd be no sun... Unless the creature is something more ethereal, something that can penetrate into every nook and cranny, extend from beneath the ground to the heights of the sky, something that people can walk *through* and still experience the entirety of this voluminous world. Something that smacks just a bit of atmosphere... **Conclusion: the creature is a mist or vapor** Which also means you don't need to worry about where it's mouth is so that people can hear it roar from anywhere and everywhere. [Answer] ### Higher Dimensions (read Flatworld) If you're amenable to more dimensions, then you could have something that exists infinitely, but takes up only a finite amount of our three dimensions. It could be as simple as the 4th dimension being time, or perhaps something further; some other Nth dimension that I can't imagine, being bounded my my own existence in three. [Answer] An infinitely long serpent-like fish that flies through the air. The fish is inter-dimensional/inter-planar, so doesn't have to physically fit on whatever world it happens to be currently inhabiting. I've seen this type of creature used in a campaign in the past (Party was in an airship swallowed by the fish, then the inside of the fish became the campaign setting and the characters had to escape). [Answer] Do [Superorganisms](https://en.wikipedia.org/wiki/Superorganism) count? If so, you could have an infinitely large ant colony. Since ant colonies can already grow [arbitarily large](http://news.bbc.co.uk/earth/hi/earth_news/newsid_8127000/8127519.stm), this isn't too far fetched. The fun part is the ant colonies could pull some [Hilbert Hotel](https://en.wikipedia.org/wiki/Hilbert%27s_paradox_of_the_Grand_Hotel) style stunts, if needed. Since you specify only one head, we will say it has only one Queen, which is the "head" of an ant colony (head of state, that is). [Answer] This is very similar to a fun math book that was circulating on the web a couple of years ago: "Life on the Infinite Farm" <https://www.math.brown.edu/~res/farm.pdf> It contains several thought experiments about what infinite animals might look like (as exercises in thinking about infinity). [Answer] According to myth, they were created when great trees displeased the Gods, and were cursed to lose everything above ground. And indeed, they do seem a little like plants - each one an immense tap root, wider than a house, drilling deep into the rock. They branch. Branches snake off horizontally through the stone, beloved by miners because the bloody wood is easier to tunnel through than rock. The branch-roots always end somewhere interesting - porous stone saturated in oil, an underground river, or even a seam of precious metals that perhaps, eons ago, used to be a hot mineral spring. But the main tap roots go only down. Perhaps they are nourished by magma. Perhaps they have found whatever lies beneath that. One thing we do know, is that they eat meat. Near the surface, the root swells to the size of a sports ground, and ends in a flat top in the soil layer. Once every decade or so, a seemingly innocuous patch of grassland will collapse when a group of animals is walking across. Whatever triggered the attack - a herd of cattle, a pack of wolves, a legion of troops - all fall into an open maw. Huge tentacles sweep across the nearby ground, blindly grasping anything that escaped and hurling them into the corrosive mucous in the throat. Eventually they calm, and weave themselves again into a lid over the pit, to eventually be hidden beneath wind-blown soil. Why do they do this? The amount they eat must be insignificant compared to the infinite body below. Perhaps it is indeed a curse. Perhaps they just like the taste. --- For bonus weirdness, you could have a similar creature living vertically in the sky - like an infinitely tall sequoia whose trunk and leaves are held aloft by vast hydrogen balloons. Tentacles swoop down to pluck up their prey. Male and female of one species? [Answer] What about a creature that has a limited height and width that is infinitely long and constantly traverses the landscape. I'm imagining something like a giant centipede or worm where there's huge arches between each supporting foot of the creature. Large enough that if it happened to come across a building (or maybe even something larger like a city) it could just step over it. The legs could follow the exact same route through the air as they move into position. And each 'foot' would land in the exact same spot that the previous 'foot' occupied. Naturally the land underneath would become super-compressed over time. Perhaps people could find a way to divert the path of a section of this creature to use the land crushed by its feet as a really flat and solid foundation for building? Anyways the creature would be infinitely long and each section would be supported by its own independent legs and feet. I'm not sure about nourishment though. Maybe a symbiotic relationship with creatures that live on it. Fungi, animals and even plants could live on something this large that is always predictable. It follows the same path with the same timings. Perhaps it moves at the same rate as day and night? This really depends on the exact workings of the day/night system. But if some sections would be in day while other sections are in night, then you could maybe have portions of this creature that are constantly in daylight and portions that are constantly in darkness. This could lead to variations in different sections of the creature and the symbiotic creatures that live with it. There's a lot of things you could do with this sort of creature as it's path could be very random meaning there'd be huge sections of land without any worm and huge sections of land that might be governed by the nearby worm paths. It'd be large enough in height that it's not insignificant and is difficulty to damage. How exactly would it recover from damage though? Perhaps some sort or merge with other pieces of the worm. That's up to you. I just like that in an infinite world there's a creature equally unending that affects almost every part of this infinity, helping form the civilizations and creatures that live in all areas of that infinite world. [Answer] # Yes, a snail Consider a snail: an initially tiny snail continuously grows new shell at the mouth, which grows wider and wider. The tiny central coils of the spiral are just the snail's shell from when it was younger. If you zoomed out, it would look the same as a younger snail. # As long as we redefine matter Snails in our universe had finite origins, and thus an initial finite size. Any real snail would have a minimum size as a result of the atomic structure of matter. But in your abstract universe, given the other infinities, we can change the structure of matter to have no atoms, no indivisible pieces. Turtles all the way down. In that reality, the snail can have infinite age, whilst remaining a finite size; the spiral could go inward forever. # Infinite animals cannot be made of atoms and live One key issue with any infinitely large creature (in any dimension) is that any signal or biological process would be propagating forever from the head. So while it could start to move in some direction, it could never finish moving. And any nutrients consumed at the head would have to be only asymptotically absorbed in an ever diminishing tail (or the tail would starve). So I think any infinite animal would have to be asymptotically small in the older direction and thus require non-atomic matter. # Snails live in the outer chambers A snail neatly resolves the issue of moving an infinite animal; though infinitely long in the spiral, the finite size and mass of the animal permits it to still move, to still procreate, etc. You have a choice whether to have parts of the animal still living all the way down the spiral, or whether to have an infinite body containing a finite lifeform living in the outer chambers. # Gabriel's shortened horn We can make Gabriel's horn shorter too. Instead of the animal growing linearly along the x axis, we make it grow exponentially along the x axis. So regressing backward in time, every year it grew half as much as the previous year. This is the frog jumping half as much each time (albeit backwards) and has finite size. # Meet the family One issue with an infinitely old animal is reproduction. If I am infinitely old, then I wasn't born, so I cannot have parents in that sense. Nor can I have children that are born and are also infinitely old. However, if I was a division from another infinite animal, then I too could divide to yield offspring. This would mean that as long as we match our infinitely-divisible matter with some mirroring phenomenon by which any animal could divide or replicate (down to all its infinite detail), then we have a way for a whole family of infinite snails to exist independently from each other yet still related. I can imagine some mirror or portal thing which duplicates an animal while halving its physical scale; the total finite amount of mass & volume is conserved, just the snail comes out half the size (as it is fractally self-similar). To understand the process you need number theory and the infinite hotel. But the effect is similar to cell division. # Two become one On the flip side two animals could merge to become one twice as big; by a process reversing that of the division, the combined animal would be an infinite merge of the original two. This gives as most of the components of reproduction as we know it, except one: a mechanism for variation. # A finite change Our snails grow in time, and as with real snails, turtle shells, tree rings, you can look back in time by looking at the historic growth of the organism. If a snail underwent some change at random intervals (voluntarily or not), then it would be visible somewhere down the spiral, even though the spiral goes on infinitely long. This would then make one snail distinct from another snail, even where they were divisions of the same animal in some earlier time. This mechanism gives us a way to have individuals, and a reason for the merging process; the snails have a way to be different, and a reason to choose one snail to merge with over another. The differences may be random (analogous to mutation) but the selection need not be. # One common ancestor All snails can have derived from a common ancestor snail; in effect a division creates twins, so whilst they can ultimately yield lots of different individuals it would suggest that looking backward down any given animal's shell you could find an original snail where all snails are the same beyond this point. The longer a snail has gone without dividing (compared to other snails), the larger it would be (given the division mechanism), so one half of the original snail could still exist alongside a larger number of smaller snails who had gone on to divide and sum separately. # Voila a snail An infinite animal, complete with reproduction, ancestry and family. [Answer] **An infinite animal can be a snake, that** starts somewhere, and then just **extends**, e.g., east, **infinitely**. There are infinite problems with that animal. Not least of which, that (assuming a random placement of other creatures) infinitely many creatures won't encounter it, ever. If it has huge girth, there is the weird problem that inifninitely many people will be hindered in their mobility (because the snake lies around like a huge wall), while at the same time infinitely many people will never see the snake in their life (because they inhabit the infinitely big part of the world that the snake is not in life-time-wandering-distance of). **If it is coiled**, or similarly distributed that its (basically) 1-D body is still all over the 2D-landscape (or even the 3D heavens) **it may be encountered by everyone, and**, given the interstices between coils are large enough) **also avoided.** Fun fact: if the scales on the snake are randomly colored, there will exist a part of the snake that has a red arrow pointing exactly into the direction of the snake head, with an exact distance to the head in inches given, in orange, and small bold black print under it "**[protagonists childhood nickname that just her siblings knew]: Go talk to the head**". [Answer] My own point of view of your problem: Your creature should have infinite size. Either of surface area or volume, but it doesn't really matter to you. You just want it **big**. So immediately, [peano curves](https://en.wikipedia.org/wiki/Peano_curve) come to mind. However, I don't think this quite fits with the spirit of your question. So first thing to consider: what does life need to live? 1. Life can reproduce itself, 2. Life can respond to stimuli, and 3. Life can grow. There are other qualifications, but they are debatable, and it is easy to imagine a type of life without them. So tackling each one by one: ## Reproduction Life needs to reproduce. How it does this is up to you, but it can't be a stand alone organism. Your organism probably needs to have various stages of life, early stages in the creature's life cycle involve moving as far away from the mother organism as possible. Middle stages involve growth and reproduction. Finally (this part is optional), towards the end of its life, it shrinks and prepares to die. ## Response This one's probably harder. An infinitely large organism would certainly have issues with responding, especially with a centralized nervous system. It would either have to react by reflex, or have separate "brains" at different spots. Each "brain" could in turn connect to a larger "brain", which connects to larger "brains" ad nauseam. How you tackle this problem could have huge effects on the sentience of the creature. i.e. the fractal network of brains could make the creature incredibly intelligent (certainly smarter than most humans), whereas reflex would make it incredibly stupid (about on scale of an insect). ## Growth This is the most difficult of your concerns. If I had to take a stab at suggesting a growth pattern, I'd suggest exponential growth where each step occurs in half the time of the last step so that it grows in a finite period of time, however how it gets the nutrients for this I don't know. Perhaps through sketchy, hand-wavy, use of light splitting into antiparticle pairs and then doing something with this, but I have no clue how you plan on discussing this if you even will. This part will take some serious ignoring of laws of physics to work. ## How I'd do it **Disclaimer:** I don't know what your goal with this is, so this is just my own ideas put into an example. So, when the creature is first born, it is a small single celled organism, it whips a little flagella attempting to get as far away from it's mother's main body as possible, as it travels along its mother's body, eating anything it can endophagize (I'll pretend that's a word). It keeps swimming until it reaches its next phase in life during which it undergoes rapid mitosis and begins to form a tendril system. These tendrils grasp at anything they can and secrete digestive fluids onto what they have, slurping the resulting fluids to the main body, which is beginning to form a central brain. The creature is about the size of a cat. The creature grows at a super fast rate as the tendrils begin to stiffen at the older spots. At stiff spots, chloroplast like organelles form to collect sunlight. The tendrils at the end begin to branch forming more mobile tendrils at each branch, smaller brains are formed each connecting to the last. The creature grows like this for almost a century, at which point it is infinitely large, it's tendrils wrapping around others of its kind forming a sort of large octopus-y forest like formation. The creature is definitely sentient, but lacks much movement capability. At some critical point, the main brain decides to die, and shuts down, killing its immediate surrounding parts. This releases new baby versions of itself which race down the tendrils at the same speed as it dies. Each brain of the original creature activates its area's death, and releases food and nutrients for the young. [Answer] It's infinite in higher dimensions. Any shape in higher dimensions would do. Perhaps infinite in all higher dimensions and not *always* in our lowly ones. At any point it can project itself down into lower dimensions and take up that space in it's entirety. This answer is inspired by [Eldrazi](https://mtg.gamepedia.com/Eldrazi), and although you don't need to follow this pattern this excerpt might be helpful: > > Each Titan lives outside of the planes. When one wants to feed, **it extends a part of its "body" into the plane, to create a physical manifestation of itself there**, as well as an army of drones that are extensions of its body and will. > > > The Spirit Dragon Ugin compared this to a man sticking his hand into a pool of water; **the man is the Eldrazi Titan, and the water is a plane. The fish--those who dwell on the plane--see only a part of the man--his hand.** Likewise, the inhabitants of a plane can see only a part of each Titan. Even if the Titans appear to be independent beings, **their physical forms are just part of a greater entity outside the plane**. The same is true for every drone that the Eldrazi had created; they are all just part of the Titan that made them. > > > [Answer] **Interesting/Horrific Idea:** Your creature is not one being but a branching collection of infinitely long snakes/dragons/centipedes. Each creature has finite width and is infinitely long but at any given time has only a finite length exposed. The remaining length is still coiled up inside the creature's 'mother' as it can never finish dragging its entire infinite length out. So travel long enough from the head you hit the mother creature. Travel long enough from the mother's head you eventually reach the grandmother and so *ad infinitum*. No member is infinitely old but the age of the members is unbounded and the entire family can be said to be infinitely old. **Further Idea:** Travel deep enough down the generations and the last mother disappears into the ground. We are living on some 'layer' of this creature. The day/night cycles are caused by it moving. [Answer] Three ideas: 1) A dome creature that messes up spacetime. Imagine this: if you are a mile away, it looks like a fairly ordinary dome, in the distance, or what have you. But the closer you get, the bigger it appears. It occupies infinite space in every direction, but is contained in compactified spacetime. It's just like how 1/x approaches infinity at 0. Right up against it, if you put your eye on this beast, it would look as though it never ends. For this to make sense, as you got close, the appearance of the rest of the world would have to bend backwards, so even what was in front of you would now be behind in some direction. This beast could easily have a well defined head at one particular location. There could be as many of these creatures as you like, so that they're relatively popular on the land. (it doesn't have to be a dome. Any creature shape could theoretically do this) 2) An infinite collection of somehow-connected finite things. I imagine an infinity of spheres. It could be that they all are managed like limbs from one head sphere. They, together, are 1 entity. Or maybe they all have a head in their centers, that share consciousness, but if N of them are destroyed concurrently, they all "die". This would necessitate they should be able to regenerate over time, if one is destroyed in some way. 3) An ethereal being that is omnipresent, but is physically accessible by some imaginative way. [Answer] If we borrow from mythology...<https://en.wikipedia.org/wiki/J%C3%B6rmungandr> ...then your creature could be a large serpent. It has a head but is still infinite because it has swallowed its own tail. But is that satisfactory as "infinite" by definition? Sure, if inside it's mouth is a wormhole that extends the creatures length indefinitely. Or, what if your creature does NOT have a head, at least not in the traditional sense. Yours is a circular cylindrical creature that has eyes and mouths and ears all over its body. At any given point of its infinite length it can see, smell, hear, and bite. How was a creature like that born? Which end came out first? Well, you could leave up to myth and the readers imagination, OR the whole creature came out of its parent all at once, already circular in its shape. That's how its cells formed when it was in the womb of whatever birthed it. Or if this is fantasy setting then just magic it. As for it not being vulnerable... the creature could be so large that inhabitants of your world think its a mountain range. Any "earthquake" would destroy even an army of attackers. [Answer] Well, since your world is also infinite, the shape of the creature doesn't really matter. There is enough room in your world for infinitely many of said creatures. So the answer should be: It looks however you want it to look. It could be shaped like a cat with an infinitely long tail, infinite hind legs on an infinitely long body, infinite front legs to support its infinitely wide shoulders, or infinite teeth in its infinitely huge mouth. Whatever the case, it just doesn't end in at least one dimension, same as your world. Since it has to be a world where our physics don't apply, our understanding of biology doesn't really matter. It could look as if made by Picasso or imagined by H. P. Lovecraft. [Answer] You can imagine all sorts of creatures, as long as they live underground. People and everyone else will be able to walk all over it without even noticing what lies beneath their feet. Give the body enough holes (or even make it web-like) and the underground denizens won't be bothered by it either. Since the ground extends down infinitely, the creature can also grow very big in all 3 dimensions. You can hide the head wherever you like. :) Bonus story opportunities: * The head could be yearning to experience the sky and flight, thus trying to move its body out (with all sorts of disastrous story-fuelling side-effects). * Since it's impossible to see any sizable portion of the creature at once, nobody (including the reader) could realize that it's the same creature until a big "revelation" later. Until then - well, you do come across these "big burrowed snake" creatures every now and then, but they're few and far between so nobody has made the connection that they're not actually distinct entities. [Answer] ## Infinitely Large Head If the animal is infinitely large, it will need an infinitely large head with which to gain infinite nutrients. To do this, simply take an regular animal, and make it infinitely wide (and also tall enough to allow things to move underneath it when needed). So it has infinite teeth, infinite stomachs, infinite eyes, an infinitely large brain (with many redundant parts), etc... [Answer] Part of the problem is that infinities are somewhat counterintuitive. The infinite hotel is a classic example. (\*) You want an infinite being that doesn't take up everywhere and lets people wander round, and doesn't get too thin? Nothing could be simpler! Your being is a conical being, which slithers along the ground, and is obligingly flexible so it can slither over other infinite beings. Its head is at the bluntly rounded apex of the cone, and cones of course have infinite volume, if they aren't truncated. There is no "thin" point, and it takes up an infinitesimal part of the world. *(\* a hotel has an infinite number of rooms, and is 100% booked. If one guest turns up, move everyone into the next higher room, and the new guest can stay in room 1. If a (countable) infinite number of guests turn up, move every guest into a room of double their present room number, which frees an infinity of odd numbered rooms for all the new guests. If an uncountable number of guests turn up, buy stocks in Cantor's AirBNB business and quit the hotel world!)* [Answer] **The Haze** The universe is filled with a mist like substance extending into infinity, this mist is in fact the diffuse body of a super-organism, able to form denser pockets to serve its various biological purposes, filled with flora and fauna which fuel its biological processes in a similar fashion to the gut-flora of more conventional creatures. The Head is a single location in the universe where The Haze started, a literal Genius-Loci. You can find the location of the Head by following an infinitesimal gradient of density in the Haze, or more conveniently by following a faint flow of energy and material which fuels The Head. Think Steven King rather than Lovecraft, The Mist, but the mist itself is a monster as much as the creatures within it. [Answer] The answer is coral. It is an animal, exists and uninhibited could grow to an indefinite size as an animal. Unlike a tree it can be cut to make more separate animals or reproduce to have larvae. [](https://i.stack.imgur.com/7ynhE.jpg) [](https://i.stack.imgur.com/L6DaB.jpg) [Answer] ## A Hive Mind As hive minds work, it can expand infinitely, just spreading from one single mind to another. To really be infinite, it should be able to assimilate any kind of living species. Let's call it: ## The Knowledge It is actually built from every living species on your infinite world and is actually looking forward to assimilating samples of every living thing. Since the power of an infinite mind is monstruous it wants to acquire the most knowledge from the whole universe. It has no real reason to assimilate every single mind since their evolution is a source of infinite knowledge for it. A hive mind actually has only one "head", aka mind but it cannot be cut out so it's really infinite in space in time. It is seen by other living organisms not as a predator but more like a god of knowledge which makes them the greatest gift, by assimilating them from time to time (they gift their minds to live forever in the hive mind). The hive mind is not blocking any dimension on earth or in the sky since it's almost everywhere and nowhere at the same time. There are no real animal instincts like on Earth, where little turtles know from the beginning they should run to the sea. The watcher actually teaches the young with the single beings he assimilated from those species to let them know the basics of their species. When the species grows communals the humanity dies, it lets them teach each other (as we do) and give them great lectures from those that have been assimilated (even eons after their physical death). This can even give the communal species a boost in innovation and actually secure all knowledge that has been assimilated until the end of time. ]

[Question] [ I remember a character I once created who was a really good sniper. When describing him, I said he could pull off a headshot on a terrestrial target from orbit. Now, in this case it was with a laser, and it was a long time ago so I didn't know as much science as I do now, but I'd like to revisit the concept in case I can ever bring it up in a future story. So let's say you're perched atop the ISS and you have a gun capable of shooting a 50-caliber-sized bullet into some unlucky guy's head, with lethal force. I realize that the chances of hitting the target are astronomically low, but I'd still like to know some things, such as: 1. What should the bullet be made of, how should it be shaped, and what does it look like before and after? 2. Say the target is on the equator. At what point is it best to shoot him, and where do you aim? 3. Does anything particularly interesting happen upon impact? I'd like for answerers to assume that this can be done; that is, if there's something that makes it impossible for a regular sniper rifle, please consider a bigger or more specialized gun that can get the job done, if one can exist. That said, the projectile should be a bullet; no guidance or stabilization after firing, and preferably just a single chunk of metal, no stages or layers. How you accelerate the bullet is up to you, as long as it's scientifically sound. [Answer] # Projectile Atmospheric Entry Simulations I put together a bit of code to compute the trajectory of projectiles as they fall through the Earth's atmosphere. I made the following simplifying assumptions: * All projectiles were fired from a circular orbit equal in altitude to the ISS (about $400~\text{km}$). * The atmosphere is non-rotating with no winds, and is identical to the [standard atmosphere](https://en.wikipedia.org/wiki/International_Standard_Atmosphere). * All projectiles fall perfectly straight: there are no lateral aerodynamic forces. * None of the projectiles' properties are altered by reentry. I computed two scenarios for each projectile. The red trajectory is for a bullet fired towards nadir (straight down), and the blue trajectory is for a bullet fired retrograde (opposite the direction of orbit). ## [.50 BMG](https://en.wikipedia.org/wiki/.50_BMG) (Ball, M33) The 50-caliber Browning Machine Gun cartridge was originally developed to fulfill an anti-aircraft role, but later became a popular round for snipers. Its high mass helps it keep its speed and accuracy, even at distances of over one mile. In fact, more than half of the [15 longest sniper kills](https://en.wikipedia.org/wiki/Longest_recorded_sniper_kills#Confirmed_kills_1.2C250.C2.A0m_.281.2C367.C2.A0yd.29_or_greater) were made with the .50 BMG. * Projectile mass: $650~\text{gr}~(42~\text{g})$ * Projectile diameter: $0.510~\text{in}~(13.0~\text{mm})$ * Muzzle velocity: $3030~\text{fps}~(920~\text{m}/\text{s})$ * Drag computed based on [data (pdf)](http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA219106) from the Ballistic Research Laboratory at Aberdeen (see figure 19).  (The dashed line shows the orbit that the projectiles were fired from.) The impact points are: * Retrograde: $2600~\text{mi}~(4180~\text{km})$ downrange in $12~\text{minutes,}~30~\text{seconds}$. * Nadir: $2050~\text{mi}~(3300~\text{km})$ downrange in $9~\text{minutes,}~15~\text{seconds}$.  (The dashed line is the lower boundary of the [stratosphere](https://en.wikipedia.org/wiki/Stratosphere) at $12~\text{km}$, slightly above the cruising altitude of most airliners.) Note that both shots impact at a steep angle. Although the .50 is heavy compared to most reentry vehicles (in terms of ballistic coefficient) it still loses almost all of its velocity to drag and ends up pretty much falling at terminal velocity.  (Above the dashed line the speed is measured in kilometers per second; below the line, the speed is measured by Mach number.) Again, we see that most of the velocity is lost in the tenuous upper atmosphere.  This plot shows the projectiles' total energy loss rate. Not all of this energy will heat the projectile, however: in fact a good portion is used ionizing and heating the air the projectile encounters. Calculating the peak heating according to [this Institute for Defense Analysis document (pdf)](http://www.dtic.mil/dtic/tr/fulltext/u2/a231552.pdf), the projectile will encounter peak temperatures of over $4000-5000~\text{K}$. Modern [ablative heatshields](https://en.wikipedia.org/wiki/Atmospheric_entry#Ablative) for spacecraft are built to withstand up to around $2600~\text{K}$ (although classified heatshield technologies for ballistic missile warheads may have moderately better performance). This means that the projectile would surely disintegrate upon entry. ## [30×173 mm](https://en.wikipedia.org/wiki/30_mm_caliber) (Armor-piercing incendiary w/ DU penetrator, PGU-14/B) This massive shell is used by several autocannons and chain guns, most notably the [GAU-8/A Avenger](https://en.wikipedia.org/wiki/GAU-8_Avenger): the primary armament of the [Fairchild Republic A-10 Thunderbolt II "Warthog"](https://en.wikipedia.org/wiki/Fairchild_Republic_A-10_Thunderbolt_II), an anti-tank air support and attack aircraft (and a personal favorite of mine). The projectile consists of an aluminum "jacket" surrounding a $10\frac{1}{2}~\text{oz}~(300~\text{g})$ [depleted uranium penetrator](https://en.wikipedia.org/wiki/Depleted_uranium#Ammunition). Although typical accuracy of the GAU-8 autocannon is only 40 yards at 4000 yards distance, the projectile is probably capable of accuracy similar to typical sniping rounds if fired from an appropriate gun (although such a weapon may be too large for a single operator, and would certainly not be man-portable). * Projectile mass: $1~\text{lb}~8\frac{1}{2}~\text{oz}~(695~\text{g})$ * Projectile diameter: $1.18~\text{in}~(30.0~\text{mm})$ * Muzzle velocity: $3030~\text{fps}~(1010~\text{m}/\text{s})$ * Drag computed based on [data (pdf)](http://www.dtd.ba/portal/index2.php?option=com_docman&task=doc_view&gid=176&Itemid=42) presented by the University of Sarajevo (see figure 9).  The impact points are: * Retrograde: $2550~\text{mi}~(4100~\text{km})$ downrange in $10~\text{minutes,}~55~\text{seconds}$. * Nadir: $2030~\text{mi}~(3260~\text{km})$ downrange in $7~\text{minutes,}~50~\text{seconds}$.  Although the shots now have distinguishably different trajectories, again they both impact at nearly the same angle (although both are more horizontal than the .50).  This time the projectiles maintain their velocity down into the stratosphere, but are still limited to terminal velocity at impact.  With the bulk of the deceleration occurring in a denser portion of the atmosphere, peak temperatures are now on the order of $9\,000~\text{K}$. ## 120 mm [APFSDS-T](https://en.wikipedia.org/wiki/Armour-piercing_fin-stabilized_discarding-sabot) (DM13) The Armour-piercing fin-stabilized discarding-sabot round is a kinetic energy penetrator designed to defeat modern vehicle armor. For maximum penetration, the projectile is more dart-shaped than bullet-shaped. The projectile I found data on is the DM13, a non-DU round similar to the 120 mm [M829 round](https://en.wikipedia.org/wiki/M829) fired by the United States' main battle tank, the [M1 Abrams](https://en.wikipedia.org/wiki/M1_Abrams). Since the fins stabilize the projectile in flight, APFSDS rounds are fired from smoothbore guns that allow increased muzzle velocity. This allows superior accuracy; modern tank crews can make a kill shot on another tank at several miles. But again it is unlikely that such a weapon could be operated by a single person. * Projectile mass: $9~\text{lb}~12~\text{oz}~(4423~\text{g})$ * Projectile diameter: $1.50~\text{in}~(38~\text{mm})$ * Muzzle velocity: $5000~\text{fps}~(1500~\text{m}/\text{s})$ * Drag computed based on [data (pdf)](http://www.dtic.mil/dtic/tr/fulltext/u2/a224217.pdf) from the Ballistics Research Laboratory.  The impact points are: * Retrograde: $1950~\text{mi}~(3140~\text{km})$ downrange in $8~\text{minutes,}~40~\text{seconds}$. * Nadir: $1340~\text{mi}~(2150~\text{km})$ downrange in $4~\text{minutes,}~40~\text{seconds}$.  Both shots have extremely straight trajectories and impact at shallow angles, indicating that they have maintained speed down to the surface.  This time the projectiles impact at hypersonic speed, delivering a devastating blow beyond the capability of any modern non-explosive round.  However, peak temperatures are now on the order of $13\,000~\text{K}$. Even though heating only occurs for a few seconds (in-atmosphere the projectile loses around a kilometer of altitude every second) the intensity is so great that the projectile will be molten by the time it reaches the surface. # Postmortem We can see that there is a fundamental tradeoff between heating and impact speed. The projectile must be large and lightweight in order to decelerate slowly and avoid burning up; however, it must also be heavy and dense to retain its speed. There is no middle ground between the two. This means that a successful projectile would have to change aspect during its trajectory, and since we're limited to "a single chunk of metal, no stages or layers," this is not possible. --- Another issue is accuracy. Since the projectile takes several minutes to hit the target, there is no possibility of a second, more accurate shot after using the first to 'scope in.' This, combined with the fact that the impact point is thousands of miles away means that all the targeting will be computerized. The position of the shooter can be pretty precisely determined (within meters) by GPS ([even on-orbit](http://www.sciencedirect.com/science/article/pii/S1270963800001309)). GPS also gives precise timing. Star trackers can give [milliarcsecond angular resolution](http://www.stsci.edu/jwst/instruments/fgs/docarchive/2010-CalWorkshop-FGS.pdf) with reaction wheels for pointing. The main challenge is aerodynamic perturbations: * The first problem is the orientation of the projectile. In the diagrams above, the projectile is shot right or down, but enters the atmosphere heading left. Thus the projectile would have to be shot backwards. * The second issue is stability. In the very thin upper atmosphere spin-stability will not work if the projectile is long and thin. [Explorer-1](http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1958-001A) (the United States' first satellite) was designed to spin about its long axis, without accounting for the (mathematically difficult) dynamics of free rotation in 3D, and it predictably transitioned quickly into a 'flat spin.' This pretty much guarantees that an inert bullet would tumble as it enters the atmosphere, no matter how we try to stabilize it. * The third issue is wind: namely, the shooter would have to account for winds through the entire height of the atmosphere; *and* be able to predict the (highly chaotic) winds nearly ten minutes in advance. # An Alternative If you're really set on shooting someone from space, you're going to need an active projectile. The projectile should consist of a $1.5~\text{m}$ long tungsten penetrator surrounded by a large sabot made of a lightweight insulating ceramic with an ablative coating. The sabot will need a large, flat front. Finally, the projectile should include a large solid motor and some variant of [solid-state attitude thrusters](http://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1887&context=smallsat). * First the projectile would be programmed with its target and released from the launch platform at a relatively low speed. * Once well-separated from the launcher, the solid motor will execute a deorbit burn. * As the projectile enters the atmosphere, the ablative coating protects the penetrator from heating. * Just after peak heating, the sabot (along with the solid motor) is jettisoned with pyrotechnic fasteners. * At this point, the penetrator begins to use aerodynamic maneuvering (like a missile) as it falls at its terminal velocity of Mach 2. * The penetrator uses GPS for terminal guidance and impacts within meters of the target. [Answer] It couldn't be done, no matter how improbably skilled the sniper, because he would lack information required to do the aiming. Regular snipers have to consider more than the direction their firing, they need to consider the weather. Snipers will use... well effectively flags to determine wind speed and direction so they can adjust for it; because otherwise the bullet will be blown off course as it flies. The longer the trip, the more time the wind has to blow the bullet off course. Now imagine a shot from orbit. It's going to be traveling a much longer distance, and thus have a much longer time to be blown off of course. It's also going to be traveling through high atmosphere where wind speeds are much greater, and far more chaotic. The wind and thermals are going to have a significant effect on the bullets trajectory. The problem is that he is firing so far that the wind speeds and direction will change as the bullet flies. This is particularly true because he is firing *down* through atmosphere. The speeds and directions of winds are not only far greater at the upper atmosphere, but they change significantly as you travel through the atmosphere. There are many winds, thermals, and other weather patterns his bullet will be traveling through. Even if we assume your sniper was a robot with an impossibly perfect AI that could instantly adjust for complex math such as orbital rotation, rate of the bullet's falling, and even change in mass of the bullet (it will be losing mass, at the speeds it is traveling, and that change would have a noticeable effect) your robot can not calculate the proper angle to fire at unless it knows *all* the weather patterns from here to your target. It's not enough to use a single flag, you're going to need to know information about weather speeds all over the atmosphere. He would need dozens of data points, at minimum, to have enough information about the wind speeds along the bullet's path to have enough raw data to make such information calculable. Unless he has dozens of weather balloons flying in a rightly diagonal line leading to his target, he simply does not have enough raw data to calculate where to shoot with any remotely reliable accuracy, no matter how perfect he is. In addition there is an even more boring problem. Even if he shoots perfectly he won't hit his target, because his target won't be there when it arrives. The ISS is quite a ways away from the ground, 400 km to be exact, and it takes time to travel that far. Assuming your bullet is traveling at subsonic speeds (if it's going at supersonic speeds you have a whole different set of issues) it can travel no faster than 342 m/s. Even if we give it the benefit of the doubt and assume that you are firing straight down, and the bullet manages to stay at exactly the sonic barrier for the entire trip, it would still take over 19 minutes to reach the ground. You're not going to be able to anticipate your target's location 19 minutes in advance when you fire. You would need your bullet to reliably move at mach 10 speeds for the entire trip to get to your target in under 2 minutes, and even that is really too long to have any reliable chance of anticipating where he will be. [Answer] **Only if the bullet is really big.** The problem with hitting someone with a bullet from space is that any tiny current of air that you did not perfectly predict is going to throw off your aim. If you're firing a bullet through the entire atmospheric column, there are going to be such air currents. Over a few seconds, through a few miles of air, it may be possible to accurately predict wind behavior, but at a flight speed of five times the speed of sound (at sea level), your sniper bullet will be travelling for around five minutes before it hits its target. You not only need to know exactly what the wind conditions below you are: you also need to know how they will act during that time. Of course, with a big enough gun firing big enough bullets, you don't need to have perfect aim. So long as you release enough kinetic energy when you hit to vaporize everything withing a few meters or tens of meters of the impact point, your bullet can be buffeted around by the wind a bit without affecting anything. With a big enough gun, it won't even matter if the target is buried deep in an underground silo, just find a gun that can shoot these: [](https://i.stack.imgur.com/d8PSv.jpg) *Pictured: a very large bullet.* *Addendum: the Chicxulub meteor is probably a bit large to count as a 'bullet', but smaller projectiles will work as long as you get them moving fast enough. Something like a 200-gigajoule railgun will probably do the trick.* [Answer] > > 1- What should the bullet be made of, how should it be shaped, and > what does it look like before and after? > > > The munition will need to be made of a material that will properly handle the heat of reentry. Tungsten or some kind of specialized ceramic should do the trick. Getting the hypersonic shape right is difficult but a pole shaped object with a small frontal cross section will bleed off energy less than the round flat frontal surfaces used in human rated reentry vehicles. > > 2- Say the target is on the equator. At what point is it best to shoot > him, and where do you aim? > > > As anyone who plays Kerbal Space Program will tell you, deorbiting a projectile from orbit so that it hits a specific point is difficult. Here's a [video](https://www.youtube.com/watch?v=m0Cun9hp_B0) of Scott Manley attempting to do precision hits with a telephone pole made of tungsten from orbit. It takes him multiple tries to hit a building sized target. Deorbiting a small projectile that can be blow off course even easier than a tungsten telephone pole. Hitting a moving target is a ba-zillion to one shot. Simple aiming from orbit will require ridiculous amounts of data to account for orbital rotation, thermals in the atmosphere, exact flight characteristics during reentry, exact orbital height, charge characteristics in the ionosphere and stratosphere, exact target position etc etc. Adding terminal guidance to the munition is your only bet of actually hitting the poor sap you want to kill. I heard once that the accuracy requirements for the Hubble space telescope are equivalent to sticking a laser pointer on top of the Washington Monument in Washington DC and hitting a dime placed on top of the Empire State Building in NYC. Given the distances involved, the accuracy requirements for this gun in space are pretty similar. > > 3- Does anything particularly interesting happen upon impact? > > > It makes a big bloody mess. Anything with sufficient mass to maintain momentum deccelerating through the atmosphere from orbit while staying on target and going a significant portion of orbital velocity will absolutely wreck whatever it hits. Kinetic energy is calculated with: $E\_\text{k} =\tfrac{1}{2} mv^2$ where *m* is mass and *v* is velocity. So, an object in [LEO](https://en.wikipedia.org/wiki/Low_Earth_orbit) has a speed of 7.8km/s. Let's assume the munition is 10kg and has lost 2.8km/s to reentry drag. So 0.5 x 10kg x 5.0 m/s^2 = 125 000 000 joules = 125 megajoules . Using this [calculator](http://www.unitconversion.org/energy/kilojoules-to-tons-explosives-conversion.html) to translate between joules and tons of TNT, we get 29.5kg of TNT. (The page doesn't note which kind of explosive is used, but TNT is a safe assumption.) So you don't have to get pinpoint close but getting close is really hard. [Answer] Most of the technical issues have been addressed in other answers, so here are a few issues that should be expanded upon: 1. A bullet made of a single material isn't going to work, since it has to deal with many different regimes during it's flight path, from space, to atmospheric entry to flying at terminal velocity to the target once it exits the plasma sheath. A dense core of something like Tungsten or Depleted Uranium will be needed to provide the high density to punch through the atmosphere without losing too much velocity. Some sort of ceramic "jacket" is needed to reduce the effects of reentry (otherwise your bullet becomes a stream of molten metal flying across the sky) and to get to the velocity needed to counter the orbital motion of the ISS and reenter the atmosphere, I would suggest a conductive layer that can interact with the electromagnetic field of a coil gun (or alternatively, a sabot with a conductive base for a railgun. 2. Since the ISS is moving at orbital velocity, you have the issue of getting your bullet to *slow down* enough to start reentry. An XKCD "What IF" (<https://what-if.xkcd.com/58/>) tells us that you could travel 1000 miles in the 3min 30 seconds it takes to sing the song "I'm Gonna Be" (which has the line *"just to be the man who walked a thousand miles to fall down at your door"*) If you just lined up a shot, you would overshoot the target drastically, hitting someone on a ship in the Atlantic when you were aiming at the Big Bad in Rio de Janeiro. A normal rifle won't provide enough velocity for the bullet to make a successful orbital change, and even a 16" naval cannon from a battleship would be hard pressed to do so, given the limits of gunpowder as a propellant. A railgun or coilgun theoretically has the ability to do so, or you could use what already works and make the projectile a rocket... 3. What will happen if the round hits the target? Nothing good. The round is moving at hypersonic velocity when it hits, so it will have considerably more energy than a conventional rifle round (depending on how massive it is [see above], it might have the kinetic energy equal to the energy release of a stick of high explosive). As well, objects moving at that speed no longer follow the usual rules of impact and energy transfer. It is usual to think of the impacting object almost as a liquid. The best terrestrial example is a HEAT warhead from an anti tank weapon. The blast of the warhead is focused on turning a cone of copper or similar metal "inside out" and accelerating it to @ Mach 25 (coincidentally nearly orbital velocity), where a few ounces of metal forces its way through dense materials like steel armour, and virtually everything else. Protection against this involves either making the explosion far enough away the metal jet loses energy (the "slat armour" on modern vehicles) or to disrupt the jet by firing a slab of steel at it a microsecond before it strikes the main body of the tank (the brick like "explosive reactive armour" you see covering Russian tanks). These are not viable options for a person to wear on their head to protect against a similar sized projectile coming out of orbit (even a building or tank is likely not going to stop such a projectile). Even a near miss might kill the target, as a hypersonic projectile will have a massive shock wave as it passes, and the impact on the ground will spall off material like concrete or rock at considerable velocity. More detailed answers will require experimentation..... [Answer] **Summary: Not for anything that could reasonably be called a "bullet"** Calculating the aerodynamics of a bullet moving through the atmosphere is hard. Fortunately, the energy levels are so high that we can ignore aerodynamics for the most part, and instead treat it as an impact between the bullet and the atmosphere. This means we can use [Newton's approximation for impact depth](https://en.wikipedia.org/wiki/Impact_depth#Newton.27s_approximation_for_the_impact_depth): $$D = L\frac{\rho\_1}{\rho\_2}$$ Depth of penetration *D* is the length of the penetrator *L* times the ratio of the penetrator's density $\rho\_1$ to the target's density $\rho\_2$. The atmospheric density is varying, but we can approximate it from the surface air pressure as being equivalent to 10 meters of water. From this, we can calcluate that an osmium bullet (density: 22.6 g/cm3) fired from orbit needs to be at least 45 cm long in order to retain a reasonable velocity at impact. Yes, you can snipe someone from orbit, but you'll be using a crowbar, not a bullet. [Answer] **Realistically**, I doubt it. There's just too much air in the way, it doesn't matter how big or heavy your bullet is, without a rocket, drag is going to slow it to terminal velocity. I mean, you'll have just as much luck and the same affect as tossing a bullet out of plane. Although that might still be lethal. **Alternatively**, there are advantages to using a ballistic instead of a laser, and using a smaller (15-20mm) round instead of an orbit-to-surface missile. A laser weapon would be extremely precise, but requires a lot of energy and doesn't deliver nearly as much 'punch'. A missile might be too easily tracked/intercepted. A small hypersonic round can be tracked in orbit using modern tech, but once it drops into the stratosphere it might be difficult-impossible to determine where, exactly the shot came from. A consideration for any sniper. The most important aspect of your story is: whatever technology required to pull of something so insane, the outcome depends on some level of human skill. So we would need to rule out a completely automated process, the 'point and click' methods. To preserve the idyllic image of a sniper with a steady hand and his eye in the scope, we should consider a lazer-guided, fin-stabilized bullet delivery system. You will need a weapon system similar to [this](http://world.guns.ru/sniper/large-caliber-sniper-rifles/at/steyr-iws-2000-e.html). I like [that](http://world.guns.ru/sniper/large-caliber-sniper-rifles/at/steyr-iws-2000-e.html) because it boasts a 1450m/s muzzle velocity. It will likely need need to be scaled up. Notice the sabot design of the bullet. Likely, we would have a similar design to our bullet, but rather than the sabot being discarded after firing, it would be used to protect the bullet throughout re-entry. This would allow us to use nearly any material for the core/bullet, for a variety of applications. Re-entry would be faster than the times given a spaceship, designed to aerobreak. Our sabot is designed to lesson drag, and maybe even burn off some outer layers. And I'm not sure exactly at what angle this feet becomes absolutely impossible - it might be impossible to shoot straight down at a target, but we should probably assume some level of hi-tech material could allow this. I remember hearing the heat experienced by an object entering the atmosphere is inversely proportional to the drag coefficient. That is why re-entry vehicles are designed to be blunt. Our projectile is meant to cut through the atmosphere at speeds a little over the space-shuttle upon entry (~9kps), so our sabot is going to need to tolerate, and I'm just guessing here, a proportional amount of heat. If I follow [wikipedia](https://en.wikipedia.org/wiki/Atmospheric_entry#Shock_layer_gas_physics)'s advice, that's *OVER 9000* degrees kelvin. Yikes! Some exotic materials for sure! You might get some real academic nerd to actually go through the calc - I'm not sure exactly how well a sabot could lesson the drag and how much that would even matter. If our sniper is deployed 100km (a 'parking' height) from the surface, assuming a 1000m/s muzzle velocity and *ignoring* atmospheric drag, the shortest hang time we could possibly achieve is ~1.67 minutes from firing to impact. We then factor (drag *times* future-tech-hand-waving). To factor drag requires such precise calculations ADD takes over . . . there are too many variables! The troposphere is thicker around the equator than the poles, and this affects the gradient density of air/elevation, and of course you must consider the size, weight, and shape of the bullet. But after all that math you might end up with the bullet finally impacting the surface at a measly terminal velocity and that's not very exciting so it is at this point we must institute some future-tech hand-waving. Perhaps the bullet has a small, in-line ramjet. But I guess that makes it an RPG. In any case estimate your sniper's bullet spends about > 2minutes en-route. ANYWAY, the general theory is, once at a low enough altitude the sabot is discarded and the fin-stabilized unit controls the decent, guided by the laser, guided by your bad\*\*\* l337 as %!#& sniper. SOOOOOO plausible! [Answer] First off, the scope necessary to make out an individual at that distance would not fit on a standard rifle, so we are talking about a highly specialized weapon indeed. You would need to account for: * The speed of the ISS and it's planar motion relative to the Earth's surface. * The rotation of the Earth itself. * Multiple layers of atmospheric disturbance and wind speeds. * Your angle relative to the target. * The speed of your projectile. * The exact altitude of the target's head. * The target's unpredictable motion. Best to hit him while he is sitting still. * The speed of light. Luckily for you, the majority of these problems have [already been solved!](http://www.nature.com/news/astronomy-laser-focus-1.16741) In order to get the incredible pictures of the night sky that we currently do from ground-based telescopes, we create an artificial star via laser, and use 'adaptive-optics', which are just mirrors on gimbals that react instantly to any distortion in the known location of this laser-star. Telescopes also have systems that move them to keep stellar object within the viewfinder, compensating for the Earth's rotation. A similar computer guiding system could line the barrel of your gun up with your target's future location with wind speeds, pressure layers and drift caused by the Earth's rotation as well as the ISS's movement all factored in. It will additionally have to take into account the difference between the laser's speed to the target and the bullet's speed. I would use a ceramic bullet in the standard shape of a sniper bullet, made via the same process as the protective tiles on the Space Shuttles to deal with the intense heat without deforming. It is essential to be as close to vertical as possible when you fire the shot, because the Earth's atmosphere will deflect your shot otherwise. You could potentially even bounce off the atmosphere at the right angle. Lastly and somewhat unfairly, you want to fire at a very high velocity to reduce the risk that your target avoids the shot, but too fast, and your bullet will burn up before it reaches the ground. This happens at around 74 km/second. As to what it will do to our victim, history is of surprisingly little help. Only one person has ever been confirmed to be hit by a meteorite (one Ann Hodges in 1954), which is essentially what you are intending to do, and she was only bruised. I suspect that your bullet will travel handily through your victim to shatter on the pavement below him leaving a baseball sized crater. [Answer] Even if we ignored all atmospheric conditions, we had no friction at all, the space station wasn't moving, and the aim of the sniper was perfectly on target, etc., you still couldn't pull it off. The most accurate sniper rifle ever made, the [Gepárd M1 anti-material rifle](https://en.wikipedia.org/wiki/Gepard_anti-materiel_rifle), has an accuracy of 0.7 minutes of arc. The ISS when closest to the Earth, orbits at an altitude of 409 km. This results in a target with a diameter of more than 80 meters, resulting just from the properties of the gun itself, without the bullet slowing down due to the atmosphere, etc. And this is the most accurate you can get with a rifle. The M1 version of the rifle I used as the example, trades absolutely *everything* for accuracy: it has almost no moving parts, is extremely heavy, holds a single bullet, and cannot be reloaded without taking it apart. A later, more practical version resembles the parameters of the famous American M82. Although the most important reason why it's impossible is described by other answers, especially by *dsollen*, I included this reasoning to point out, that even if all the issues raised by the other answers were non-existent, you still had a 80 meter target area as a *best case*. [Answer] Perhaps he has a sci-fi-sniper-rifle. As the bullet leaves the barrel of the gun, it uses some faster-than-light/hyperspace type technology to instantaneously skip ahead, emerging just a few meters from the target. In this way, wind/gravity effects and moving targets, are no loner an issue. You only need to establish line of site with your extremely telescopic scope. Presumably the bi-pod helps stabilise, while adjusting for the earth's relative motion. [Answer] Using any kind of gun is redundant. All you need is something that is streamlined and has a suitable terminal velocity. Get one of these... ...[](https://i.stack.imgur.com/lMDwR.gif) ... and, using your super aiming powers, just drop it. By the time it reaches the ground it will be going so fast that it will go straight through your target and several metres into the ground as well. If your aim isn't so super then your best chance is to adjust the position of the target. Capture him and get someone to drive him to the estimated point of arrival of the 'bullet' as it falls. It can be tracked by a miniature embedded transmitter. [Answer] **Use a really long bullet.** So long that it's mass keeps it from being blown off course. Perhaps the tail of the bullet could be engineered to predictably burn up shortly before hitting the target. [Answer] If we can have a specialized gun, I'm going to get one with a lot of barrels. It'll shoot a massive array, which will compensate for a lot of issues. Or maybe we can just go with a specialized cluster projectile that disperses into an array before some predetermined point of impact. These options would cause quite a bit of collateral damage. I'm sure the projectile could be rigged with some limited guidance options to change course before impact, compensating for atmospheric changes, environmental variables, moving target, etc. ]

[Question] [ It’s just another average day in the life of modern day earth. Suddenly a transmission from orbit washes over the planet! Oh no! An alien race, calling themselves the “Thull”, has suddenly arrived in their spaceship and declares war on our race, threatening genocide! They are undoubtedly real, as anyone with a moderately powerful telescope can see their ship in orbit, and there was an obvious effect as their ship “slowed down” or ”transferred from hyperspace” or method it used to travel. Acting quickly and perhaps rashly, one of the governments of the world sends a nuke up. It has surprisingly good aim, and actually collides with the spaceship before detonating. To everyone’s surprise it obliterates the Thull spaceship and every one on-board. This is probably because the most advanced war-fighting technology the Thull had were steak knives and tinfoil shielding. North Korea claims responsibility. ## Assuming that: 1. By and large, it is accepted that the Thull were real 2. And that their spaceship was real,used FTL, and didn’t *sneak* close to the planet 3. All physical traces of alien technology are now useless bits of scrap 4. Their method of ftl drive/travel doesn’t use handwavium or unobtainium (it can be built by things the people on the planet have available). Recovery of the scrap shows no traces of anything unobtainable. 5. Humanity doesn’t self-destruct TOO MUCH at the reveal of other intelligent life out there. What’s a realistic expectation for the collective of humanity for the length of time to determine the ftl method and build their own ftl ship/probe/test-bed? Keep in mind, all they really have is the blatant demonstration that it’s possible and some of the outward observable effects, they have to work out ‘how’ on their own, with only the knowledge that its possible and within grasp (demonstrated by the general (lack of)advancement of the Thull). ## Edit Everyone, Thanks for the responses so far! Most of what people are saying is that it’s not possible to determine, and if that’s the consensus then I can accept that, but I keep thinking back to an idea; During World War 2, suddenly someone had a nuke and without question demonstrated it was possible to create that device. Where before places and nations only had theories, now they had proof, and within a relatively short period of time other places created their own nuclear devices. In-fact, *most* other places that had access to the brain power and materials figured it out. Isn't this sort of example usually the case? It takes forever to make/invent the first one, but once people "know x is a thing," shortly everyone has it. Coming up with a working idea in the first place is hard for humans, but recreating it is "less hard". Or is this off base? ## Edit2 Its seems the general consensus is "not enough information" which is fair. It leaves me a little freedom to work with the timeline, but for my use-case, ultimately what I'm hearing is I will have to decide on what timeline works best for the story, but probably a minimum time of a few years. If I could I would +1 everyone that contributed,but I feel Serban Tanasa provided the most useful answer because he elaborated out the different degrees of technological differences that could exist in a simple way. [Answer] It depends on how far from the current production possibilities frontier this technology is. There are several possibilities, depending on the technology gap: 1. It is like the **Apollo Moon mission to Stone Age hunter-gatherers**. We (the hunter gatherers) can probably recover some debris, use it to bash stones or store berries, but we have neither the industrial base or the scientific framework to comprehend and replicate the technology. 2. **Helicopters to Leonardo**. Leonardo understood the concepts of helicopters, but didn't know about internal combustion engines. Given the field of debris from a helicopter crash, Leonardo might infer a few advances, but will likely be unable to build a helicopter. It would still revolutionize technology, though. 3. **Nukes to Stalin**. Russian scientists knew nukes were possible. There was even a nuclear program. Knowing that the Americans had done it and stealing American tech allowed the Russians to build the same project quickly, without the steep and costly learning process that the Americans had to undergo. If this is the case, we'd have FTL within one to three years of the 'attack'. [Answer] Impossible to answer. I'm using the answer format rather than a comment to get enough space to explain. * FTL travel will probably require a [paradigm shift](https://en.wikipedia.org/wiki/Paradigm_shift) in science. The necessary theoretical hints may or may not be observable. Imagine somebody like [James Watt](https://en.wikipedia.org/wiki/James_Watt) gets a tour of a nuclear power plant, but without a helpful tour guide. He might have recognized the turbine building, and concluded that turbines rather than reciprocating cylinders are the way to go for steam power, but guessing where the power comes from would be impossible. * Without the breakthroughs, who can tell what the [manufacturing tolerances](https://en.wikipedia.org/wiki/Engineering_tolerance) of the FTL drive are? If somebody had handed James Watt the blueprints of a jet turbine, he might well have concluded that it is a neat concept but utterly impractical, because he can't come up with the bearings and blades to take the strain. * We think that we understand nuclear fusion, but it has been "a couple of decades away" for a couple of decades. Questions are supposed to be off-topic here if they are idea generation rather than specific stumbling blocks in your fictional work. Without knowing how your FTL drive works and what the observable side effects are, we can't help you. Or to put it another way, decide what outcome you want for your story and then consider how to make it happen. * Can spectroscopic analysis of the attack tell us about unusual elements in the debris of the alien craft? * As a minimum, consider how long the development of an airliner or a jet fighter takes, both today and during major wars. Years to decades. * Can the FTL drive function on Earth or only in space? If we have to take the labs to a space station, add a decade or two. --- Edit: The Royal Navy deployed an [AEW variant of the Sea King](https://en.wikipedia.org/wiki/Westland_Sea_King#Airborne_early_warning) in 11 weeks. Both the helicopter and the radar were existing, they just had to integrate them. The [Mercury Project](https://en.wikipedia.org/wiki/Project_Mercury) took a couple of years, based on existing rockets and a new capsule. The [B-2](https://en.wikipedia.org/wiki/Northrop_Grumman_B-2_Spirit) took a more than a decade. The [F-35](https://en.wikipedia.org/wiki/Lockheed_Martin_F-35_Lightning_II) went operational a decade after her first flight. Does that mean a great sense of urgency can accelerate sluggy R&D, or does that mean modern aerospace craft are *much* more complicated than a wood-and-canvas biplane? I think so. Wild guesstimate: At least a decade for theory, at least a decade for orbital infrastructure, at least decade to build a prototype, and that is optimistic. [Answer] > > *During World War 2, suddenly someone had a nuke and without question demonstrated it was possible to create that device. Where before places and nations only had theories, now they had proof, and within a relatively short period of time other places created their own nuclear devices.* > > > Comparing nukes to FTL is an incorrect analogy, and examining why will explain why simply knowing FTL is possible does not help determine how long it will be before we can do it. During WWII it wasn't "suddenly someone had a nuke". [The physics of nuclear fission was understood and published in 1939 and 1940 by the Germans and Soviets](https://en.wikipedia.org/wiki/Nuclear_fission#History). We, meaning humanity, knew a nuke was theoretically possible, and we knew the basic mechanism by which it could happen. It was the *engineering* to make a practical device that was lacking, engineering that was far, far beyond anyone's expectations at the time. [The Manhattan Project](https://en.wikipedia.org/wiki/Manhattan_Project), the first successful nuclear bomb, was at a scale beyond anything previously. What knowing FTL can work, plus the fear of someone else using it against us, does is get *funding*, so important for the practical implementation of an engineering project. Going back to the nuclear analogy, [the Germans had their own nuclear program](https://en.wikipedia.org/wiki/German_nuclear_weapon_project), but it was never at the scale of the Manhattan Project. The Manhattan Project got its funding, in part, because of the idea of the Germans getting a nuke first and the many scientists warning the government of that. Underfunded hypothetical FTL projects on the drawing board like the [Alcubierre drive](https://en.wikipedia.org/wiki/Alcubierre_drive) will suddenly get funding. But they're still lacking a lot of basic physics to understand how to do it, much less get the energies involved down to something we can practically produce. --- A better analogy is AI and the human brain. We know from the human brain that you can make a computer which does the things humans can do. Since the 60s we've been predicting that computers which can think like humans are right around the corner... and it's remained right around the corner for the last 50 years. Even things like [Siri](https://en.wikipedia.org/wiki/Siri) and [Deep Blue](https://en.wikipedia.org/wiki/Deep_Blue_%28chess_computer%29) are still performing specialized tricks, they don't think. What it comes down to is *we still do not know how the brain works* and *how we build computers is fundamentally different from how the brain works*. We know AI can work, we are thinking machines, but *even with seven billion working examples* we're still an unknown amount of time away from AI. It's not an engineering problem, we lack the basic understanding of intelligence, learning, and consciousness. --- Furthermore, the other analogies of great technological leaps offered: pre-WWII nukes, Renaissance helicopters, Stone-Age Moon landing, even AI... *these are all steps into the unknown*. They wouldn't violate known and tested systems. Leonardo had no working knowledge of aerodynamics, and cavemen had no tested ideas about orbital dynamics. Those are all problems which were (or can be) solved with more research, more theory, and more experimentation (and more money). In contrast, we have a huge body of theory and evidence which says not only that the speed of light is the fastest you can travel, but that ***the speed of light is the speed of causality***. Breaking, or working around, the speed of light isn't like breaking the sound barrier. FTL isn't about more powerful engines or a better understanding of aerodynamics. ***If you go faster than the speed of light you break our fundamental and well tested understanding of how the Universe works***. [Watch this video to understand](https://www.youtube.com/watch?v=msVuCEs8Ydo). Achieving FTL means either throwing out our understanding of the Universe and somehow constructing a whole new one. Alternatively we'd need to build one of several hypothetical work-arounds which warp space-time such as the [Alcubierre Warp Drive](https://www.youtube.com/watch?v=94ed4v_T6YM) which require tremendous amounts of negative energy. [Negative energy has only been produced at quantum scales](https://en.wikipedia.org/wiki/Casimir_effect) and quantum things tend to not scale up well. --- This is why just knowing FTL can work, and having the motivation to fund its development, doesn't mean we can predict when it will happen. We only have untested hypotheses about how FTL *might* work, but there's a lot of basic science we don't understand. What can be said is we'll achieve FTL faster than we would otherwise. [Answer] This idea has actually been explored in the short story [*The Road Not Taken*](https://en.wikipedia.org/wiki/The_Road_Not_Taken_%28short_story%29) by Harry Turtledove. In the story, the aliens invading Earth had FTL technology but lacked any other significant military technology, much like the aliens in the question. Having discovered FTL in their Age of Sail, they travel in conquistador-style submarine-like spaceships, and attempt to invade Earth with black powder weapons. While their ship was not actually destroyed in the story and could be directly reverse-engineered, the idea that such travel is even possible would quickly galvanise scientists to work on the idea. Since the aliens described in the question are similarly under-developed in their war-related technologies, it is highly likely that their early discovery of FTL has therefore stunted their scientific expenditure in fields such as engineering and weaponry, and that humans have far surpassed them in these other fields. As a result, humans should be technologically far more advanced than the aliens in non-FTL fields. Any engineering feats that the aliens can create would be trivial by human standards. Current scientific theories imply that FTL travel is impossible, and scientific inertia is an important factor in the advancement of science. Max Planck [famously quipped](https://en.wikipedia.org/wiki/Planck%27s_principle) that: > > A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die and a new generation grows up that is familiar with it > > > A clear demonstration that FTL is in fact possible would mean that the vast majority of scientists capable of working on such an idea would immediately begin to obtain massive amounts of funding and resources and research FTL. Turning FTL from a scientific pariah into the most militarily and economically important question would likely result in billions to trillions of dollars being poured into its research. If the aliens could discover FTL with pre-industrial levels of population and scientific expenditure, it is not unreasonable to think that humans would be able to do the same relatively quickly with millions of times more resources at their disposal. All humanity needs is to think along different lines from previously established science, as flaws in previous theories had likely led to the stagnation of FTL research. [Answer] Well, warp travel (or w/e these aliens use) may well be ***physically*** possible, but keep in mind that nuclear power was always possible as well - it just wasn't ***achievable by mankind*** until the 50's (aka at least ***70 thousand years*** after we climbed out of trees in dear, ol' Africa). In the short term what would happen is that anyone who would be able to get their hands on a piece of the alien craft would do so. They would analyze the heck out of each piece, and conflicts between nations may very well arise over who owns them, or who gets access to them. A lot of research groups and think tanks would be established in order to examine everything about the aliens. "Experts" and other know-it-all types would probably declare that it's now only a matter of (short) time until humanity is interstellar, and make all sorts of crazy predictions. A lot of professors would be applying for grants in order to "analyze" the problem, that's for sure. Quite probably an international space defense coalition would be formed, which would give the US a ***great excuse*** to put nukes in orbit. You know, to keep us all ***safe***. Cough. Other than that? Quite frankly it would serve as a great boost to humanity's confidence that we ***could*** one day spread to other stars, but without significantly more to go on we won't be discovering the alien's way of travel any sooner than we might have otherwise. [Answer] I would say that it would take a very short time (months, 2 or 3 years at most), for the following reasons: * You mention that: "and there was an obvious effect as their ship “slowed down” or ”transferred from hyperspace” or method it used to travel." -- The obvious effects would have to include various easily measurable phenomena using current technology. Including various electromagnetic traces with unusual spectra, exotic particles, and various gravitational effects due to the sudden appearance of additional mass in earth orbit out of seemingly nothing. Consider how much Galileo, Copernicus and Newton were able to learn from observing the movement of the planets with 18th century telescopes, and now imagine what 21st century scientists would be able to figure out once they measure the effects of an alien ship coming out of FTL. * Humanity has typically been able to achieve a lot scientifically when driven by war: Look at the technological development that occurred because of WWII and the Cold War. Now imagine what will happen if we were under threat of an alien invasion. * Historically, once something is shown to be possible, others figure out how to achieve it very quickly. The very fact that the mind set switches from "Is it possible" to "When will it happen" changes the way people approach the problem. * There is already a theoretical framework for FTL called the "[Alcubierre Drive](http://iopscience.iop.org/article/10.1088/0264-9381/11/5/001/meta)" (This is legitimate theoretical physics, not pie-in-the-sky sic-fi proposals). Wormholes are also a theoretical possibility according to general relativity (Physicists call them Einstein-Rosen bridges). Chances are, if aliens suddenly showed up in orbit, this would allow physicists to quickly fill any gaps in the above mentioned theories and create workable FTL devices. [Answer] There are a few difficulties in answering this question, so let's go through them in order: 1, If it uses an engineering concept radically different from ours, I would say the possibility is nil. Consider this scenario: A modern F16 crashed during World War 1. What is the possibility of the Germans replicating that technology based on the remains? Exactly zero percent, as they do not understand the advanced electronics or the concepts used in micro-controllers and their software. 2, If it uses exotic materials, then the possibility is close to zero. Like making an F35 with World War I technology. 3, If crucial components auto-destruct, then the possibility is zero. Most military hardware is rigged so that it can be disabled to prevent leaking sensitive information to the enemy. If none of these difficulties arise, then the only question is time required. I would say in the magnitude of a few decades... [Answer] I'd agree that knowing that something is possible can change everything. When you know that it's possible, the question shifts from "if" to "how". It leads to a totally different mindset. That said, the Atom Bomb example is flawed. Scientists had been building up atomic theory for literally thousands of years -- the ancient Greeks had discussed the idea of atoms. Yes, they never identified what the real elements were and got tripped up on important points, but they had the fundamental idea. Universities all over the world taught facts and theories very close to what was needed. It was just a matter of going one more step. Even if the U.S. had never built an atom bomb, I think it's likely that someone else would have built a bomb or a reactor within a decade or two. But in the case of FTL travel, it's not a matter of the basic theory being there and we just need one more piece of the puzzle. No one has the vaguest idea how to build an FTL drive. I guess if we had proof that FTL was possible, scientists would start revisiting all the reasons why we presently think it's not possible, and maybe they'd find the mistake. If the alien visit left one solid clue -- if examining the wreckage revealed that the ship was fueled with lithium chloride or that the engines emitted charmed quarks or whatever -- that might give more hope. Otherwise ... I'd say we'd still be looking at centuries. One could always postulate an inspired genius who figures it out, another Kepler or Newton or Einstein, in which case the key breakthrough could be tomorrow. I'd expect it would still take many years to get from the theoretical breakthrough to a working model. [Answer] I believe the time would be relatively short (though my WAG is between 5 and 15 years, so partial agreement with @Alex Kinman). Though my answer depends primarily on one very important thing: *The obvious observable energy signature(s) of the FTL exit occurrence, MUST align with one of our existing theories for FTL, otherwise I doubt we would make much additional headway.* (Another point to support quick development of FTL in your scenario: I would take it as evidence that the technology level required for FTL may not be that far from our own based on the fact that a nuke was able to get to, and destroy their ship.) **Reasoning:** If we are in any position to understand the FTL drive used by the Thull, AND in any position to produce said drive, our level of understanding of the universe must be deep enough to include the idea. If, on the other hand, there is some theory that must later supplant the Theory Of Relativity, and/or our general understanding of physics, prior to us being able to understand and build an FTL drive, then us being able to get there any time soon is not very likely (to agree with @AndreiROM). **Some possible support for the idea:** There are enough theoretical concepts of how FTL might be possible with current understanding: [Warp Drive](http://www.nasa.gov/centers/glenn/technology/warp/warp.html) [EmDrive](http://www.techtimes.com/articles/49360/20150428/nasa-may-have-accidentally-discovered-faster-than-light-travel.htm) [Wormholes](http://helios.gsfc.nasa.gov/qa_sp_sl.html) [And a wikipedia article on FTL in general](https://en.wikipedia.org/wiki/Faster-than-light#Justifications) Hope that helps. [Answer] Not really an answer, but some thoughts for the sake of completeness. 1) Given that Thull ship was in the Earth orbit, most of the debris which are not evaporated by the nuke would enter the atmosphere and burn. So I see no way for direct proof that there was no unobtainium involved. 2) However, those remaining debris would probably be hunted for (there goes reusable rocketry!) and examined scrupulously. This alone would take a year or two. Regardless of what was found, some nukes and more telescopes would end up in orbit (bye bye radiophobia, and more rocketry). The mere signal that "FTL is possible" implies a major review of general relativity which currently forbids FTL. However, GR is extremely robust - it has been under constant scrutiny for a century now, and held. Building a viable alternative would probably take a generation or two. The whole situation would be a huge boost for physics-related science in general (just as the Cold war was, but at a greater scale since the adversary is so far ahead), but training a modern scientist takes like 10 years (and *real* scientists would argue that it's more like "the whole life") so it won't pay off quickly. Generally, the encounter will be beneficial for mankind, but not quite enough to discover FTL unless it's really, really close. 3) Now a couple possible events that could speed things up: 3.1) The entrance of the Thull ship may have been accidentally recorded by human telescopes. Even though one data entry is not much data, it would be a good boon. Especially if it somehow gets noticed by something like [LIGO](https://en.wikipedia.org/wiki/LIGO). 3.2) The collected debris may turn out to be not as advanced as expected. Say they use bare transistors and not chips, or barrel-loaded guns, or something like that. This may encourage the scientists even further. Still it looks like years to tens of years... Maybe the Thull aren't coming because they are equally scared... [Answer] Let's look at some other examples: ## Birds wing -> heavier than air flight Depending on how you look at it - hundreds of years to all of human history. We didn't understand the concept of the aerofoil, or know how to achieve propulsion. We could see birds flying, but only had handwavy ideas as to how they were achieving it. ## US Nuke -> Russian Nuke The concept of nuclear fission was public knowledge. There were scientific papers in the public domain. The Russians knew how it might work, the challenges were to do with measurement and engineering. ## Alien FTL -> Human FTL Without a theoretical framework, I would say this is more in the bird wing category. It would certainly spur scientists into action, but they would have little idea what avenues to explore. ]

[Question] [ In a world where the development of internal combustion engines had been seriously delayed (for whatever reason), would it have been possible to power heavier than air aircraft by steam propulsion? And would this have been a practical proposition? For example would they have been able to cross the Atlantic? Assume the simplest level of technology (between the late 19th century and today) that would make this possible (if it is possible). Add any specific key technological innovations that have occurred which you believe would be necessary to help. Lighter than air aircraft are out of scope. [Answer] Here is a scheme to sidestep some problems with steam engines in an alternate past. **Problem**: Fuel is heavy **Solution**: Do not carry fuel. [](https://i.stack.imgur.com/6XIeW.jpg) <https://images.fineartamerica.com/images/artworkimages/mediumlarge/1/mouchot-solar-concentrator-1878-science-source.jpg> I introduce the good Mr Mouchot, a man ahead of his time. <https://en.wikipedia.org/wiki/Augustin_Mouchot> > > Mouchot was drawn to the idea of finding new alternative energy > sources, believing that the coal which fueled the Industrial > Revolution would eventually run out. In 1860 he began exploring solar > cooking, drawing on the work of Horace-Bénédict de Saussure and Claude > Pouillet. Further experiments involved a water-filled cauldron > enclosed in glass, which would be exposed to the heat of the sun until > the water boiled; the steam thus produced would provide motive power > for a small steam engine. By August 1866, Mouchot had developed the > first parabolic trough solar collector,[2](https://i.stack.imgur.com/r1kT1.jpg) which was presented to the > emperor Napoleon III in Paris. Mouchot continued development and > increased the scale of his solar experiments. The publication of his > book on solar energy, La Chaleur solaire et ses Applications > industrielles ("Solar Heat and its Industrial Applications") > (1869),[3](https://i.stack.imgur.com/Rwrgf.jpg) coincided with the unveiling of the largest solar steam > engine he had yet built. This engine was displayed in Paris until the > city fell under siege during the Franco-Prussian War in 1871, and was > not found after the siege ended. > > > No doubt the prototype was spirited out of France to Quebec by a disciple of Mouchot, to keep it from falling into the hands of the Germans. The solar steam plane will use a steam engine with a solar boiler. --- **Problem**: Water is heavy **Solution**: Do not carry water. The Atlantic is full of water. The solar steam plane will fly low over the ocean, capitalizing on the [ground effect](https://en.wikipedia.org/wiki/Ground_effect_(aerodynamics)) for extra lift. A fill hose will pull water up from the ocean below to supply steam as needed. --- **Problem**: solar steam engine requires a very large dish solar concentrator. **Solution:** Use large dish solar concentrator as wing. Behold: the Nemeth Parasol! > > In 1934, the Nemuth Parasol, built by students at Miami University, > demonstrated that even a circular wing could be used to fly a plane > reliably. > [](https://i.stack.imgur.com/Rwrgf.jpg) > <http://www.popularmechanics.com/military/g1420/17-bizarre-aircraft-we-love-and-the-stories-behind-them/> > > > The solar steam plane will use its very large fixed wing as its concentrator. The dish will reflect and concentrate the sun by virtue of a near-weightless micrometer coating of gold foil. It will be covered with a pane of window glass to serve its aerodynamic function at the same time. --- **Problem**: Solar steam plane can only fly when the sun is up. **Solution**: Complete flight while the sun is up. St. John's in Newfoundland and Labrador, Canada is 3,091 km from Killarney, Ireland. No-one would dispute that to go from one to the other one must cross the Atlantic. At the latitude of St John's, the day is 16 hours long on the summer solstice. Assuming flight is possible during all 16 of those hours that would mean 3,091 km in 16 hours = 193 km/hours; converted to miles this is a leisurely 119 miles per hour. Hopefully now I can put this concept out of my head enough that I am not compelled to make a picture of the golden dish plane, puffing its steamy way low over the Atlantic under the solstice sun. [Answer] You may be missing why flight didn't happen until the early 1900s. ## Flight happened *when* engines became energy-dense enough. That's what they were waiting for. If it could've been done with steam, it would've. That said, with refinements such as the *steam turbine* (over the reciprocating pistons) and better metallurgy in the boilers aimed at making them lightweight, it would be possible. ## You can't just scoop water from the ocean Anybody who thinks that has never fired a steam engine, nor managed water supply for one. Sheer availability of water is a huge factor, and the main limitation to operation of steam locomotives today. However water quality has a big impact on maintenance and longevity. Modern steam operators are very sensitive about their water quality. The engines that fueled from wells and local creeks also spent an awful lot of time in the shop getting cooled down and washed out. You'll have trouble doing that in the air, unless you have 4 boilers. (2 to fly, 1 to fail, and 1 in maintenance cycle). So if they're up in arms about *well* water with its ordindary mineralizaton, you can imagine where salt water would be. Fuggedaboutit! Boiler #2 would need service before you could get #1 cooled down, let alone washed out! You could purge the contaminant-heavy water before it condenses to solid, but then you would have to jettison large fractions of your hot water (after spending the energy heating it up!) ## Close the loop - recover spent steam Fortunately, aircraft have plenty of airflow. Given adequate metallurgy tech, you would be able to make your steam system a "closed loop", and recapture spent steam in condensers. Nuclear reactors already do this because the spent steam is contaminated. Gas plants also do it because polishing recovered water is cheaper than treating new water. (Polishing is a minimal treatment/filtering done to remove contaminants as they accumulate.) This would add weight and "wetted area" aerodynamically, but would solve the supply problem. Your system would need to be relatively leak-free, or it would have to be designed to leak into the condensers. You would not be able to carry a whole lot of makeup water. You could scoop it from lakes or *gulp* the ocean, but it would need better treatment equipment, and if the system leaked faster than the treatment plant could run, you passthrough under-treated water and accept the increasing scale and loss of efficiency, and hope you can make it to your destination or at least a diversion field. ## Carrying enough fuel isn't a problem An ultra-modern steam plant is nearly as efficient as an internal-combustion engine, so getting shaft horsepower from the fuel won't be the limiting factor. Really it will boil down (heh) to an efficient, elegant design optimized for the single purpose. [Answer] # Very, very cautious maybe > > * 1934: Newspapers of the time reported a steam-powered aircraft designed by a Mr Huettner, Chief Engineer of the Klingenberg Electric Works in Berlin, that used revolving boiler combined with a steam turbine. The plane was reported to have a design speed of 260 miles per hour (420 km/h) and be capable of 60 to 70 hours non-stop flight.[[12]](http://trove.nla.gov.au/newspaper/article/92355774) The Berlin reporter of the Czechoslovak Prager Tagblatt, who wrote the article, was arrested, and no more was heard of the project.[[13]](https://en.wikipedia.org/wiki/Steam_Car_Developments_and_Steam_Aviation) > > > [From Wikipedia](https://en.wikipedia.org/wiki/Steam_aircraft) 60 hours at 400 Km/h is 24 thousands kilometers. It is more than needed to cross from Europe to USA - popular London - New York route is only under 6 thousands kilometers long. **But** reporter got arrested and no one seen this plane in action. Of course this is one of the weakest evidences you are going to get, but it shows it was not unbelievable in 1934. In your world, all you need to do is to assume it was truth, and there was no competition from internal combustion crafts to drive it out of the market. [Answer] YES!!! It was done! I am astounded by the lack of historical knowledge here. Steam is a totally viable power system. With automobiles, it was initially the *primary* choice for engines, over electric or gasoline options, due to exceptional horsepower and torque potential and lack of need for any kind of transmission (plus almost silent operation for later models). The reason gasoline started to take over on the ground was the potential for an auto accident to lead to a boiler explosion on early type boilers. As far as aircraft, steam engine powered heavier than air craft were tried several different times, the most successful one was the Bessler. <http://www.flyingkettle.com/besler6.htm> <https://www.youtube.com/watch?v=l4P4FWZFPz4> Obviously, this is based on 1930s era steam technology which was greatly refined over that of the mid-19th century. The Doble company utilized flash boilers that could attain a head of steam in mere seconds, were impossible to cause to explode, and use recirculating water through an inter cooler to reuse water instead of just venting it. There is no reason a steam engine is inherently incapable of powering a heavier than air craft, especially once you start using lightweight "flash boiler" technology. More advanced steam engines were on par with gasoline engines for power to weight ratios. The reason gas dominated with aircraft right from the beginning was a slight weight advantage followed by dominance in the automobile industry, which meant that tooling and expertise tended to lean to gasoline power. With good gas engines, there was no outstanding need for steam power in aircraft. The primary advantages a rankine cycle engine has (such as 100% torque at zero RPM) are nowhere near as useful for an airplane as they would be for, say, a heavy truck. Logically enough, trucks were some of the last holdouts before the diesel engine was really perfected. [Answer] [](https://i.stack.imgur.com/VsdK3.jpg) Propane was first invented in 1857. I mention this because we're discussing 19th century solutions. My solution would be a propane or toulene-powered closed-loop system steam engine. William John Macquorn Rankine advanced the study of heat engines by publishing the “Manual of the Steam Engine and Other Prime Movers”. Rankine developed a complete theory of the steam engine and indeed of all heat engines back in 1859. Together with Rudolf Clausius and William Thomson (Lord Kelvin), he was a contributor to the thermodynamics, particularly focusing on the first of the three thermodynamic laws. **Rankine cycle Engine** The Rankine cycle is an idealized thermodynamic cycle of a heat engine that converts heat into mechanical work while undergoing phase change. The heat is supplied externally to a closed loop, which usually uses water, but can also use touline or as I suggest, liquid petroleum gas as the working fluid. [](https://i.stack.imgur.com/Th3ue.jpg) The Rankine cycle can use an organic fluid such as propane, pentane or toluene in place of water and steam. This allows use of lower-temperature heat source and operate at around 70–90 °C. The efficiency of the cycle is much lower as a result of the lower temperature range, but this can be worthwhile because of the lower cost involved in gathering heat at this lower temperature. Alternatively, fluids can be used that have boiling points above water, and this may have thermodynamic benefits. See, for example, mercury vapour turbine, but at a significantly higher weight than water. **Why use propane** Liquified Petroleum only weighs four pounds (4.11) per gallon, so it's half the weight of water (8 lbs). Vapor from propane expands to 270 times it's liquid dimensions (270:1) and it uses a much lower boiling point (-44 F) and compresses into a liquid at 350 psi. In addition to providing a motivation source, propane can serve a dual-use as a fuel to heat liquid. Propane as a liquid is pretty stable with a flammability window roughly between 3-9% concentration. **What I'm holding back** Steam engines were developed for airplane use, but there were better sources of power, so development went another direction. For instance, one could just use the propane as a power source for a pulse jet motor, which has excellent thrust-to-weight, and has been used in aviation for the V1 Flying Bomb, but was not invented until 1907, so it doesn't fit in the timeline. Gasoline internal combustion motors overtook steam engines because the electric starter removed one of the biggest drawbacks to the technology. **Trivia Facts** * The photo is of the first propane powered plane appeared in 2013, which used an internal combustion engine, therefore would not be a solution. * Steam engines are very efficient. Steam is used in nearly every factory and electrical generation plant as a motivator around the world. Nuclear, geothermal, coal, gas, even some solar plants use steam to create power. One could envision a day when steam-powered vehicles come back into vogue. * Ormat created technology that uses butane (a component of propane), and waste heat to generate electricity, which is an example of this technology in use. * <https://en.wikipedia.org/wiki/Rankine_cycle> * <http://gas2.org/2013/07/29/aviat-flies-first-cng-airplane-at-oshkosh-2013/> * <http://www.ormat.com/en/home/a/main/> * <https://en.wikipedia.org/wiki/Propane> * <http://www.propane101.com> Special thank you to @Thucydides for describing the process and @MadPhysicist for challenging me to rewrite this. [Answer] The problem with steam is not the mechanics of the engine, per se, as a piston engine can be designed using steam. The problem is in the need for water and fuel to heat it. Water, especially. Coal was very heavy. When gasoline became a fuel, it would have made the steam locomotives lighter, but diesel-fueled steam locomotives were not developed simply because it was more efficient to bypass the water. Modern nuclear reactors use steam to drive electric turbines, and they recycle the water. But they use great quantities of water to cool the radioactive water. If you can solve the water weight problem, you have a chance. [Answer] It's a matter of power to weight ratios. Steam engines are very heavy for the power they deliver. Steam engines have the benefit of needing only very simple technology. An internal combustion engine, which has a much better power to weight ratio, requires higher tech and a specific fuel... the rather volatile gasoline. A gas turbine engine, which has the best power to weight ratio, requires even higher tech due to the high speed that the turbine rotates, and the metals needed to withstand the great heat produced. As an example of weight ratios, consider one of the largest steam locomotives ever built - the [Union Pacific Big Boy](https://en.wikipedia.org/wiki/Union_Pacific_Big_Boy). It produced around 6200 HP, and weighed 762,000 pounds. In contrast, there is the [P&W T34 turboshaft](https://en.wikipedia.org/wiki/Pratt_%26_Whitney_T34) engine, which produces similar horsepower ratings, but weighs only 2,600 pounds. In some forms of transportation, such as ships, weight isn't a major issue, while with locomotives, weight is desirable to add to the locomotive's traction. Steam power was used on both locomotives and ships long after the invention of the internal combustion engine because it was less expensive at the time, and weight wasn't a factor. More than any other form of transportation, aircraft place an emphasis on light weight, so steam powering an aircraft simply isn't practical. [Samuel Langley](https://en.wikipedia.org/wiki/Samuel_Pierpont_Langley) built a model aircraft using a miniature steam engine to power it, which flew for 3/4 mile. His attempts to upscale that model into one that carried a human used a 50 HP gasoline engine failed to fly. [Answer] As people have mentioned, the Besler brothers actually flew an aircraft powered by a steam engine in 1933. At that time they claimed they could fly 400 miles on 10 gallons of water and believed they could increase that dramatically with better condenser technology. Their engine could only generate about 1/2 the horsepower of gasoline engines of the same weight, so they were never seriously considered.. but it certainly could have powered an aircraft on a trans-Atlantic flight. The aircraft would have just had to sacrifice payload capacity. [Answer] **Mostly no,** **With 1900's tech this is unlikely. But not impossible.** Steam engines are relatively simple, but with a lot of science they can be optimized. **A steam engine needs water** In order to get your plane across the Atlantic your plane would either need to get water from the ocean or be able to recycle its water. A condenser component did exist in the 1900s for some steam engines. **A steam engine needs fuel** The fuel needed to heat the water needs to be efficient, providing a lot of energy for little weight. At the time, coal was the preferred energy source. It is energy dense but not completely efficient. **The most critical aspect of a steam engine is managing Heat** Heat lost by the system is essentially wasted power. The system expends heat on * bringing fuel to ignition. * bringing water to boiling point The system needs to lose heat in condensing water as part of the condenser. If you can utilize all of the systems heat you can burn less fuel increasing the duration of your flight. **But now to the actual question, is this possible in 1900s tech.** They had the components (condensers), they knew about insulation (likely asbestos), they had the math to understand pressure in different parts of the system. They had mechanical systems that could sense temperature and pressure. Its not impossible that these could come together then. The reason this is unlikely is because in that time period the level of understanding needed to optimize each aspect of the system (the engine, thermodynamics, aerodynamics, material composition) was unheard of. **In that time period, it was more about strapping things that worked, into something that worked.** The plane was literally made by taking an engine that had the highest power to weight to fuel efficiency at the time (which happened to be the emerging combustion engine) and strapping it to a construct light enough and strong enough to produce lift. In the 100 years since the plane came into existence the wing was literally improved every decade if not half decade. [Answer] --- > > **I was so absolutely sure this ideas was completely absurd that I didn't even bother to research the issue. I stand by my analysis in terms of the practicality of steam-powered flight, but it did happen. Note that the moment gasoline is invented the combustion engine will obsolete steam, requiring your world to never invent gasoline... or natural gas for the same reason... Nevertheless, I'm impressed! Thanks, @Slarty, for pointing this out! [YouTube](https://www.youtube.com/watch?v=nw6NFmcnW-8), [Wiki](https://en.wikipedia.org/wiki/Steam_aircraft)** > > > --- Whenever I hear steam-powered questions I think "steampunk." Please note that it's usually easier to explain the early creation of specific technologies than it is to explain the late development of any technology. The problem is what I lovingly call the "technology dichotomy," which describes having a high-tech ability without the supporting low-tech infrastructure. In your case, with every passing year technologies are created that will obsolete steam. Most of which wouldn't exist without the technologies you're looking to suppress (those supporting combustion engines). Here's why that's an issue: Steam engines need much more weight to operate than combustion engines and rely on energy that's much less efficient. **Weight** The water is obvious. While the ground effect gives you extra lift, the reason planes fly at high altitudes is the air friction is a bigger pain than the ground effect is a benefit. It costs more fuel to fly near the ground. Besides, pumps add weight. > > No matter how well designed, the entire water infrastructure (the water itself and the metal to contain it) is additional weight requiring that much more energy to lift. > > > The metal used has a ton of effect on the outcome. The [1903 Wright Brothers biplane](http://www.wright-brothers.org/Information_Desk/Just_the_Facts/Engines_&_Props/1903_Engine.htm) was powered with a combustion motor made of 92% aluminum, which suggests that even aluminum is not light enough to solve the steam-powered problem. Add to this the nature of the two engines. The combustion engine wants all the combustion it can get with as little heat possible. It's the explosion that's valuable. (Desire: High combustion, low heat.) Compare this to a steam engine where you want all the heat you can possibly get because the actual combustion process is worthless to you. (Desire: low combustion, high heat.) Said another way, combustion engines are designed to withstand the force of combustion. Steam engines are designed to withstand the force of heat. > > Steam engines benefit most from an alloyed metal that is light with excellent thermal conductivity: but the technology infrastructure to develop that alloy would bring about better forms of motive force than steam. > > > **Fuel Value** Steam fuel is remarkably inefficient. A pound of coal produces 10.1Kbtu of heat. A gallon of gasoline produces 146.5Kbtu of heat. ([Source](https://www.eia.gov/electricity/annual/html/epa_07_03.html)) A gallon is 231 cubic inches. Coal density changes its volume substantially, but an average value appears to be 55Lbs/cu.ft, which means there are 7.35 lbs in 231 cubic inches for 74.24Kbtu of heat. > > Coal produces half the energy and is required to lift additional weight. Ruthlessly, that's like saying it has 25% the value of gasoline. > > > **The solution: bring a future technology back** Frankly, your solution is *electricity.* I have serious doubts that a steam engine directly driving a prop could possibly lift a plane into the air. And that ignores the fact that you might need to land every 200 miles to refuel and rewater. > > You're real goal is to make the need for the steam engine as small as possible. > > > Combine a much smaller steam engine with an electric generator, some batteries, and a good flywheel, and you're good to go. It might be possible to get that ruthless 25% value up to 75%, which hits the believability zone. [Answer] I don't have enough reputation to comment, but I wanted to point out that most later steam engines used diesel, not coal, as a fuel source. That cuts down on a lot of weight. Both diesel and propane are 19th century fuels. Diesel can be produced from petroleum or from biomass. Propane can be made from gasified coal. Steam rockets are *not* internal combustion engines. Steam is made in a boiler and vented through a nozzle to create thrust, and this tech dates back to the 1st century AD. It's possible that a steam airplane could have a massive steam tank that is pre-heated and pressurized on the ground. Once launched only a smaller amount of heat is needed be used to keep the tank at optimal pressure. Propulsion might be possible via a steam rocket or steam-powered turbine engine. Onboard steam and fuel usage can be further lowered by launching the craft with a steam catapult or steam-powered disposable booster rockets. Since the OP allowed for some 20th century tech as well the power to weight ratio can be significantly improved by the use of aluminum and titanium alloys. [Answer] As many of the other posters have suggested, the key is to condense and reuse the water. Strangely enough, the best solution may be one designed for IC powered aircraft. During the 1920's and 30's, *Heinkel Flugzeugwerke* attempted to build high speed aircraft for the Luftwaffe. The chief designers were very enamoured of evaporative cooling as a means of making the airframe aerodynamically "clean" and wringing the maximum performance out of the relatively low powered engines of the era. Rather than take the coolant from the engines and run it through radiators strapped under the wings or fuselage (the box like protrusions you see under the wings of aircraft of the era) the Günter brothers experimented with evaporative cooling. The engine coolant was allowed to boil, and the vapour streamed to condensers built into the wings (where the combination of airflow and large surface area made for very effective cooling). The clean and lightweight designs were very fast, but problems with coolant leaks made to apparent that this was not the way to go with a warplane, particularly when considering the wings could suffer battle damage from bullets and shells. [](https://i.stack.imgur.com/VR1Tj.jpg) *Spitfire. Like most aircraft of the era, the engine coolant is fed through the box like radiators under the wing* [](https://i.stack.imgur.com/IE3mi.jpg) *He-100 prototype. The clean wings and lack of radiators are very apparent here* For a civilian airliner/cargo plane, battle damage is probably not going to be a consideration. However, the complex condenser will have plenty of points where it may leak, and will be a maintenance hog for the users. Combined with lightweight flash boilers, and sufficiently lightweight engines (piston or turbine) and a suitably high density/high energy fuel, there is nothing physically impossible about a steam powered aircraft. As a practical matter, the extra mass of equipment and maintenance burdens, coupled with a lower power to weight ratio means that a steam aircraft will have less performance than an equivalent IC or turbine engines aircraft. There is one alternative, although it stretches the definition of "steam powered" quite a bit. The ME-163 Komet was powered by a steam rocket engine. The HWK 109-509 bipropellant hot engine, which added a true fuel of hydrazine hydrate and methanol, designated C-Stoff, that burned with the oxygen-rich exhaust from the T-Stoff, used as the oxidizer, for added thrust. In order for this rocket engine to power larger and heavier aircraft, water can be injected into the combustion chamber to cool the chamber and add more mass to the exhaust, providing greater thrust. Other chemical reactions can generate high pressure steam as a byproduct of the reaction, for example passing highly concentrated hydrogen peroxide over a catalyst. This can be enhanced by injecting and burning a fuel, which is how the "[Walter](https://infogalactic.com/info/Hellmuth_Walter#Rocket_engines)" engine worked in late WWII German submarines, and Walter rocket engines were also used during WWII. [](https://i.stack.imgur.com/jNgP4.jpg) *HWK 109-509 bipropellant rocket engine* [](https://i.stack.imgur.com/m4tq9.png) *Walter HWK 109-500 aircraft rocket engine* [](https://i.stack.imgur.com/a5Wqe.jpg) *HWK 109-500 JATO units boosting an Arado 234 jet bomber* In this case, using the steam rocket engine, a large glider like aircraft is launched and rises to a high altitude, then glides the rest of the way across the Atlantic. [Answer] how about a steam/electric hybrid? steam engine shrinks to the size needed to provide enough power for cruise, and at altitude the radiator has -50C air to play with. perhaps we could use a naptha engine, or a compounded steam, naptha, or a kalina cycle engine to benefit from the low temp heat sink? [Answer] ## It depends on how you define steam power Allow me to explain with the best example I have: Must nuclear reactors are extremely energy dense, but they ultimately use water-steam conversion to make practical use of the nuclear power in order to convert it to electrical power. In most cases there is a measure of steam recovery to close the cycle and either active or passive cooling of the steam to be able to re-use it. Is a nuclear powered cross-atlantic flight possible? Absolutely. So, in essence, that means a steam powered flight is. It just uses a far far less obvious fuel source. [Answer] Steam powered turboprop engines are also a possibility no one's attempted to address. Also, some ice airplanes have gearboxes instead of having prop attached directly to crankshaft. Steam powered piston engines are heavier than gas or diesel when compared by horsepower but if I'm not wrong generate more torque, allowing them to take further advantage of a gearbox. but I'm not an engineer so maybe I'm wrong ]

[Question] [ I don't want to outright go out and say it: "Billy found the +5 magical staff *Rynn's Lament*," since a) that would [be a n00b mistake](http://tvtropes.org/pmwiki/pmwiki.php/Main/InfinityPlusOneSword) and b) my character is [not called Billy](http://tvtropes.org/pmwiki/pmwiki.php/Main/NoNameGiven). [**In my worlds**](https://worldbuilding.stackexchange.com/questions/12990/a-most-subtle-magic), magic is subtle and not flashy at all, so how can I introduce a powerful magical weapon in this context? Most or perhaps even all of the magical effects are such that they can be easily mistaken for chance and coincidence. Nonetheless, it should gradually become apparent to the Not-Billy character and to the reader that this is no ordinary item. Unless your responses convince me otherwise, I plan to have it look like a rather plain (if well built) wooden-looking staff with metal ends. I'm currently thinking a good answer might have one of: * a set of **subtle** abilities for the wielder to gradually discover that make them realize there is something unnatural about the weapon. * a way of establishing the weapon's/device's provenance that would be gradually revealed (fragments of lore or a lost instruction manual?) either in the process of acquiring the weapon (I'm guessing it doesn't just lie by a skeleton on the side of the road, unnoticed for centuries by the myriad local peasants), or gradually afterwards. Limitations: * The object in question is *not* given by a scantily clad godlike entity living in a lake at the end of a dangerous quest, and is *not* found in a golden jewel-encrusted chest with "[Vorpal Sword of Doom +5](http://tvtropes.org/pmwiki/pmwiki.php/Main/PowerGlows)" written in demonic runes underneath. * The wielders do not know this is a magical weapon prior to acquiring it, and indeed will likely come to possess it rather by accident, as it were. * Nor will this device/weapon be explicitly identified as such by some bard or lorekeeper in an inn going all jelly-legged at the mere sight of it. Again, the key operating word is ***subtle***. Lightning strikes are out, unless they're explicitly fighting an armored knight on a mountaintop during a storm. This is not idea generation, so I'm not asking you to list weapon abilities (although I won't hold that against you if you do as part of your answer), merely for a way of identifying a weapon as magical in a way that's not "in-your-face". [Answer] A few characteristics you might expect of a powerful magical item: * It's tough - things that you might expect to destroy it simply don't. This gives a chance for it to reveal that there is something unusual about it, even if it isn't announced. * It is storied. Perhaps NotBilly has heard of the staff, even if she has no idea that this is the staff that she is carrying. This then gives her a chance to make the connection for herself if she is smart. * It is tied strongly into the magical realm, this may not be flashy but if there are some people ( or creatures in general ) who are more sensitive to it, they will notice something unusual. Maybe there is a type of animal that is attracted to it, so wherever he goes he starts to find cats are drawn to him, or sparrows. * Magic is unnatural, so it interacts unusually with nature - if it's left on grass, perhaps the grass dies back or grows longer. Placed beside a vase of flowers maybe they die back with unusual rapidity or start growing as though they are still planted in the ground, reaching towards it as they would towards the sun. * Subtle powers that it might confer could include influence, where the bearer finds that their suggestions have more weight than they once did, adeptness, where they are just a little more balanced or if it is used for its purpose ( as a weapon, a weight carrying aid, a cooking implement, etc ) the bearer will find themselves naturally better at that thing. It could confer insight into situations or augment the bearer's memory. The most powerful indicator of either of these would be if they lost it and found their previously gained strengths suddenly receding. * Alternately it may be bound to the person who it has chosen, so no matter what they try to do, they actually can't get rid of it. * It actively suppresses any attempts to use magic around it by others. This could be exceedingly subtle and it might take a very long time for NotBilly to notice, but it is an interesting possibility. [Answer] A few ideas 1. A slight feeling of vibration/humming when touched. Not noticeable at first when you aren't looking for it, but which you slowly become aware of. Similarly a slight glow in a dark room (not noticed for several days, perhaps, because why would you notice?) 2. A slow-growing "connection" to the object: a little like the One Ring slowly asserts influence/possessiveness on the carrier, but without the creepy killing everything thing. At first it's just an object, but after a while the carrier notices that they have a sense of it's presence 3. Similar to above: the carrier slowly becomes more capable, or discovers knowledge they shouldn't have. Either having this capability increase slowly, or simply having them notice after a while that they could do the thing while holding the item, but not otherwise, and the common factor was the magical item. The effects can be as strong or subtle as you like, because the first few times it happens will be written off or not linked to the presence of the staff/item 4. The item only "fires" in certain circumstances: ie when the character is under threat. They notice when they should be drowning and don't, or are pulled to the surface. Or when the staff blocks an arrow, or twitches to jam and stall the holder just long enough to not be hit by a bullet. It just seems like a normal item until this occurs, so they may not notice for weeks until in danger. All of the above are only really effective if the object is useful in it's own right - ie if it's a staff or bow or knife, rather than a stone, as the holder needs a reason to carry it without it being magical. [Answer] **Subtle Enhancement** I'm going to point to one of my favourites rpgs of all time (Because it IS the best rpg of all time.) In Morrowind (TES:III), one of the (earliest) best legendary items in the game you can find is a ring that permanently boost personality and willpower. Making interactions with NPCs much more bearable early in the game without obliging you to put precious points into both traits when leveling up. Such a ring has no distinguishable 'magical' effect. But has the potential of greatly affecting gameplay. Same goes with any item that would make you 'run a bit further', 'jump a bit higher', 'talk with a bit more conviction' etc... (You get where I'm going with this). The effect can remain unknown for a ridiculous amount of time. (Mostly until you repeatedly lose it and notice the difference with and without) **Subtle Protection** An item that would say stop any weapon from piercing your skin for more than a few millimeters. Enough to allow you to be wounded but never fatally. An item that would allow you to hold your breath longer, or protect you against fatal poisoning/infection/disease etc... **A Series of Circumstances** An item that subtly affects the world around you. It could warp perceptions, making people often stop thinking about you the moment they aren't directly interacting with you (perfect for a thief), or enemies could end up always tripping/falling/stumbling in the worst moment, stopping them from harming you, etc... Or making it 100% certain, your opponent does indeed get struck by lightning in a storm :) What I don't think is possible is a high profile 'active' magical item. I.E.: It's hard not to notice the magical flames on a *magical flaming sword*. *So how would this magically subtle object be discovered as magical?* My answer is as I said above, the bearer needs to be estranged from it, perhaps more than once, for differences with and without to start being noticeable. [Answer] The "Elderly Care Walking Assistance Units" used to be commonplace among the Numenoreans of old, with their subtle warping of the reality matrix to prevent injuries caused by falls, help walking speed, boost stamina and famously using neuromorphic read/write software to enhance night-vision, ward off mosquitoes and other pests. Their zero-point-drives ensured convenient no-battery operation for forgetful elders. Later on, during the desperate last days of the Wars of the Greater Abominations, a significant number were weaponized in a doomed attempt to stop the unstoppable, with custom combat plugins and situational awareness enhancements. Most of the staffs were of course destroyed during the fiery end of the Old Ones. Of the few surviving ones, most were neurolocked so indistinguishable from a regular stick, or their software programming had long faded into the semisentient equivalent of senility. It just so happened that NotBilly's neuropatterns (possibly due to her descent from a long-impovrished line of local gentry) combined to make a 91% match for the neurolock recog software, and the eccentric semisentience within, perhaps our of sheer boredom, decided that was good enough for it. [Answer] Another way for the wielder to notice that there's something about the weapon in a subtle way could be parting with it, then reuniting - the idea being that the effects are so subtle that the wielder doesn't notice themselves until they build up over time, and the wielder adjusts to them habitually. When the weapon (and hence its effects) are removed, the dependence on something that has vanished is much more noticeable than the effect itself. [Answer] Subtle magic is a funny thing. Just watch Apollo Robbins work his craft removing watches from people at parties, and you have to marvel at it. Of course, such subtle magic cannot be overt. If everybody could see it was magical, it would fail to qualify as subtle. Thus we see the first rule: "the staff must give hints to the wielder that it is magical in a way that is hard for a third party to observe." An obvious answer would be a loud booming voice in someones head announcing "you have a magic staff, let me teach you how to use it." But that hardly qualifies as subtle. Certainly not by Rynn standards. Let the games begin, shall we? Our staff has the clear necessity of helping its wielder unlock the staff's true potential, without overtly guiding them towards those ends. So it's going to have to rely on its greatest ally: patience. It's simply going to have to continually work with its new owner until one day the owner starts to put 2 and 2 together and realize the answer is at least 4.1, and seems to be going up every day. The owner clearly has a will. Anyone wielding a weapon has a will they wish to impose on others, or else they wouldn't be wielding a weapon. The staff can patiently wait, sensing that will. When it sees an opportunity, it may do just slightly more, or slightly less than intended. If the owner strikes out, it may hit the enemy, even though the actual butt of the staff was just shy of a strike. Most staves are wood, flexible, but once in a while, it might flex just a little more than you thought the wood should be able to flex, allowing the staff to strike around a block instead of being stymmed. In this phase, the staff is merely trying to make sure the owner realizes it is special. This phase continues until a key psychological shift occurs: the owner gives identity to the staff. Instead of thinking of it as "a staff," the owner begins thinking of it as "this staff," a unique individual. The owner might even choose to give it a name. Regardless, once the staff has an identity in the owner's mind, the staff has a beachhead to begin the real work of teaching the owner how to use it correctly. The staff may begin to display emotions. It may communicate ("My staff feels sluggish today... perhaps today is not a good day to fight. We should rest instead."). Such "illusions" of personality are not unusual for fine weapons, so nobody besides the closest co-horts of the wielder would even notice. Even they would just think the wielder is a little nuts. *In fact, those illusions show up in so many myths, it really leaves one to wonder, doesn't it?...* Once the wielder has admitted a personality to the weapon, we can begin the final dance between weapon and wielder. Now that we have two personalities in the mix: a wielder and a weapon. Now we have a solid back drop to build the real training upon: social interactions between individuals. Maybe it shows up as the wielder just "knowing" what the weapon is thinking. Maybe there's a physical dance, where every single strike or parry conveys the spirit of the dance between weapon and wielder. Maybe the sanity of the wielder buckles, as he or she begins to hear voices. In every step of the way, the weapon is going to need to earn its keep. If the wielder is going to be ridiculed for talking to his staff, the peanut gallery better be silenced when they see the wielder and weapon dance across the corpses of their enemies. Fortunately, a staff owned by Rynn would be up to the challenge. The wielder? That's another story. Since nothing is overt, the owner can't simply wield the staff "to great victory." That would show off obvious magic. Instead, the two individuals need to work together. The wielder needs to get used to being told where to stand, just like the lead in a dance needs to have a subtle sense of where the follow would like to flourish. A strong individual will appreciate this dance, and never let their partner go. A weak individual... well... The lead has to be strong, but able to listen to the spirit of the follow. If the lead is not strong, the dance crumbles. If the wielder cannot be the lead, because they are not strong enough to keep up with the needs of the staff, Rynn's staff will be more than willing to oblige the wielder, and become the lead. In such cases, madness would surely follow, but the madness would never quite cause destruction until a time suspiciously convenient for the staff to find a new wielder. *Alex's lungs burned with exhaustion as the staff hummed with vibration from the force of the last blow. All eight royal guards that had been sent to escort him to the prisons lie at his feet. Two were still breathing; it almost felt as though the staff still had a purpose for them, still vibrating to its own tune -- imperceptibly unless you looked hard or listened carefully. The remaining witnesses, Alex's companions in crime, had long since fled. They had fled not from the royal guards and the summons they brought. The gang Alex rolled with was far too loyal to leave one of theirs behind. But when the first guard began spurting blood, layrinx collapsing under a blow so fast that neither gang member had even realized the staff was inexplicably in Alex's hands, they fled. They had seen Alex take a life before, but not like this. Not like this.* *Alex coughed, a spasm of pghlem and a little blood. No guard had struck him. Heck, only the last had had the time to even take a full swing at him -- folly, at that. Alex readjusted himself. It wasn't easy getting used to striking so furiously that even his own organs struggled to keep up with the demands placed on them. His staff knew where he needed to be, it was Alex who found himself constantly the weaker party, the party struggling to catch up.* *"I swear, if I knew half of what this staff seems to know, I'd have no peers," he muttered to himself, feeling his arm ache. The vibrations from the strike were still surging through the staff, like the vicious sting of a bat struck against a rock or a wall. It ran up and down his arm, though he did nothing to extinguish the vibrations. Alex felt it would be rude to the staff, like he'd hurt its feelings if he tried to take back control of his arm once more, removing it from this ringing.* *Alex heard the two living guards whispering. No, no. That wasn't quite it. It was definitely more than just two voices. Alex dropped to his knees. The auditory hallucinations of his dead foes wore on him, moreso after every fight. Dropping to his knees in submission seemed to be the only thing that had any effect on their prattle as it rose from a whisper to a shout. He held fast, on his knees, vibrating staff in hand, waiting for the voices to end. And they did.* *What replaced them was far more sinister than the taunts and goads of dead warriors. Their voices were replaced in an instant, silenced, to let one pure voice ring through. Her voice was almost melodious, smooth, without a hint of malice. And yet what she had to say was more than Alex had ever had to bear.* *"I have decided to accept you as my student," she purred, as calm as though there were no corpses piled up around them. "You should know what that means." The pain from the vibration in Alex's arm diminished, and he focused more on this new voice. It was this, or eternal madness, he decided. Better this.* *"You should know what this means, Alex. It means I will have to break you. It means I will break you. You are my student now, so it must be."* *"So it must be."* *A short while thereafter, an Alex gathered his stuff and headed East, towards the town. He would meet up with his friends there. There would be words. Alex breathed easily now. The worst was over, or so he tried to tell himself. He knew it was a lie, of course, but it was a good lie. He sighed effortlessly, walking away from the pile of eight dead royal guards - walking away from the small pile of his phlegm and blood slowly seeping into the dirt. He took a breath, pondering what an autopsy on two of the guards would reveal: lung damage that could only be explained by a tremendously lucky blow to just the right spot on the sternum, through the armor plates. He took another breath, thinking just how lucky he was that his lungs might heal so quickly after he hurt them so badly. Lucky, Lucky, Lucky.* *A third breath, and they was gone.* [Answer] **Some people are looking for it** If NotBobby happens to find this mighty weapon by accident, it isn't impossible that GenericEvilGuy has been searching this item for a long time and happens to find out that NotBobby has it. In this way, GenericEvilGuy will find NotBobby and try to take the weapon from him, on the way explaining his evil plan before doing it, because [that's what evil do](http://tvtropes.org/pmwiki/pmwiki.php/Main/EvilGloating). **The previous owner is still (almost) there** OldJohn used to have the weapon, and in his eternal greed, locked himself inside an old cave with the weapon to make sure no-one would take it from him. Fortunately, OldJohn was a little crazy, so he had a journal. Being alone with a magical item doesn't generate lots of conversation so OldJohn was usually writing about his findings of the magic weapon and of the flying unicorns he saw on the ceiling. The hero, NotBobby, happens to find the weapon in the cave, where OldJohn is long time dead due to hunger and thirst, but his journal remains. Maybe a part of it was destroyed by humidity(?) so the hero can't fully understand the power of the weapon, or maybe OldJohn didn't speak the same language as NotBobby, so he'd have to quest up to AnywhereLand to find a sage that could help him discover the power of the weapon. **Good ol' flashbacks** *"NotBobby found what he was looking for. Reaching for the old trinket in the madman's pocket, his hand barely touched his wooden staff; a weird weapon for such a powerful man. Upon touching the weapon, NotBobby felt nauseous, thoughts of hatred took over his mind, it was unbearable. NotBobby wondered for a moment if the terrible odour of a decomposing murderer's body combined to the deep disgust he had for the character was to blame or if the staff had something to do with this."* **Subtle stuff** * A wooden staff with metal ends might be somehow heavy. Maybe this staff isn't at all. The weight could either go unnoticed by the wielder because he didn't pay attention, or he could figure it out right away. Then again, it might be confusing if the staff is simply made of rare materials that are incredibly light, or if some sort of magic is involved. * A staff isn't *that* damaging. It hurts being hurt with a long wooden staff, but maybe this staff is even more effective. If the character was to try to hit a rock with it, maybe the rock would shatter, which wouldn't go unnoticed. Monsters fought by NotBobby would react in a more intense way to the hits delivered by the weapon. [Answer] KISS. Maybe an slight *aura* of menace or radiance. *Warmth* perhaps. Very slightly glowiness. Of course, if this was the dread blade of ***skogroth the squirrel slayer***, all the squirrels in the area going deadly silent... That said, first *boring* magical blade that came to mind was the blade from Conan the Barbarian, which he took from crom/the king in the barrow. It had one property. It wasn't rusty. Also was sharp. A *unaged* weapon in a pile of rusted out junk might work here. I'd also consider the elven blades from LOTR. They had fairly mundane magical properties, and fairly well leveled up *stabbiness*. [Answer] One trope you could use in conjunction with others is: Antagonists who are magically attuned start saying things that sound like NotBilly is the Chosen One and they're intimidated by him. Gradually, though, NotBilly realizes that they're not talking about *him*, they're talking about the item. For example, the question you asked reminded me of a scene in The Legend of Zelda: Skyward Sword. In one of the encounters with the primary antagonist, he remarks to Link that he's met his match while battling the hero. Later, it's implied that the antagonist isn't actually talking about meeting his match in Link. Instead, he's talking about the spirit inhabiting Link's sword, who is more powerful than Link realizes! (This also foreshadows that the primary antagonist is himself the spirit of a powerful item, which is used by another villain in the final boss battle.) [Answer] I have a few suggestions, but their applicability will depend on the rest of your setting: **1. How it's found:** If the previous wielder used it to escape a trap, this would justify it laying dormant for hundreds of years (particularly if the wielder was only partially successful. Example: NotBilly is at a local temple when there's a massive rumbling through the floor. The clerics unseal the entrance to the abandoned catacombs beneath the temple, and send NotBilly down to investigate. Down there, he discovers a room filled with stone rubble, and a plain wooden staff jutting up, unscathed. The room had had a "collapsing ceiling" trap (Indiana Jones style) which had been triggered by some adventurer centuries ago. The adventurer had used the apparently-unbreakable staff to hold up the ceiling, and had either escaped or starved. After hundreds of years of focusing all its weight on a single point of wood, the stone slab of the ceiling had finally cracked and collapsed to either side of the staff. If the area is humid, the fact that the staff is still in perfect condition (the metal caps would be free of rust) would also indicate that it's not a mundane item. **2. What it does:** When wielding the staff, NotBilly wouldn't *feel* any different, but he'd wind up using the staff almost as an extension of his body, even if he had no training with such weapons. If he trips over a root, he darts the tip of the staff out to brace himself and maintain his footing without breaking his pace. If someone throws a rock at him, even if it's from a direction he can't see, the he whips the staff around to block it (maybe not necessarily successfully every time). Maybe he even bats it directly back at the thrower. If someone swings a sword at him, he blocks it with the staff, and it makes a sound like you'd expect from a steel blade impacting wood...but the staff remains unscathed. When he tries to hit someone with the metal ends of the staff, he seems to always find just the right spot: maybe he clocks them in the elbow and makes them drop their weapon, or slips through their guard and stuns them with a blow to the head. **3. The weapon is special, not the wielder:** You could also illustrate the weapons capabilities by taking it away from NotBilly (perhaps a villain steals it while the hero sleeps, or replaces it with a mundane staff), and NotBilly loses the capabilities to which he's grown accustom...and the villain gains those capabilities until the weapon can be retrieved. [Answer] A lot of your options for the most subtle (early) clues depend on how much of NotBilly's thoughts and observations you are describing to the reader. Most answers above are very good, but seem to depend on what Billy himself notices about the staff. I would instead advise having other characters be the first to remark on the weirdness going on. The weapon influencing NotBilly's behavior helps you explain why he keeps it around, even if he doesn't know it's value, while you slowly show him refusing to abandon it despite increasingly adverse circumstances. A few examples: * NotBilly injured his ankle prior to finding the staff. He picks it up as a useful crutch, but after he's healed, he keeps using it. Another character remarks on it, to which NotBilly responds that it looks well-made and should provide a pretty penny at the next market. * While at the market, NotBilly is short on cash, but refuses to sell the staff, depriving him and companions of something useful. * During a visit to a temple/library/etc, NotBilly is told to leave the staff outside. When NotBilly gets defensive, the priest/guard maintains that it "clearly is a weapon." He runs off in anger. * At this point another character might start to gather lore, none of which seems to match the weapon or what's happening. * Some person spots NotBilly's staff and accuses him to theft, loudly. When the law officer arrives, NotBilly claims it is a family heirloom (which the reader and companions know to be a lie), but then he proceeds to accurately describe every tiny detail of the staff and its carvings accurately despite the law officer holding it out of his sight. He convinces the law officer, but alienates his companions, who complain that he's derailing the (main plot) with his staff-related antics. In the meantime, you can have the staff cause beneficial if unlikely events for NotBilly that can't be traced back to the staff directly. Once the reader is clued in to the staff (magically) affecting NotBilly, he/she will think back and connect the dots. At that point you can let NotBilly flail around a little longer to increase the reader's frustration/anticipation before he finally figures it out himself or until the staff dramatically saves his hide if NotBilly is a bit too dense. From there on out, you can introduce more lore about the weapon and have NotBilly *attempt* to use it intentionally. [Answer] As Not-Billy is initially unaware of the staff's magical properties, he'll probably initially use it outside of combat situations in the sorts of ways any ordinary staff might be used - as a walking stick, leaning it against a desk or table and setting his hat on it, spanning it between two tree branches to dry his laundry over, manipulating objects from a distance (e.g. retrieving the shoes he kicked off last night), as a lever, or to carry something over the shoulder (e.g. water pails or a knapsack). In any of these situations, the powerful magic can subtly assert itself through apparent accidents, such as: * While using it as a walking stick, the end of it just happens to land on the one floor tile that conceals a hidden compartment; the distinctly hollow sound is obvious. * While his hat is hanging on the end of the vertically-oriented staff, it just happens to get knocked over by an errant breeze. In the process, the hat rolls or drifts (depending on its weight) to land directly atop something uniquely relevant to Not-Billy's current situation. * While drying his laundry across the staff, an article of his clothing suddenly falls off of it. When he picks up the garment, he discovers that it fell due to the weight of an item in one pocket. He does not recall ever having acquired the item, and in fact he is sure it was not there when he was washing his clothes. The item is also completely dry. (This one is more obvious, and might be reserved for when Not-Billy has failed to make the connection from many prior clues. For a more subtle event: the clothes get dry much faster than they normally would.) * When using it to extend his reach, he fumbles and the staff slips from his grasp. It rolls across the floor, and where it stops, one of the metal ends reflects a beam of sunlight (or light from a nearby fire, if at night) onto something he hadn't noticed was there. ...and so on. Some other, more random, possibilities: * While Not-Billy is carrying the staff as he browses through a shop filled with knickknacks, the end of the staff knocks a small object off a shelf and directly into his backpack/pocket. Neither Not-Billy nor the shopkeeper notices, but the object just happens to be something that Not-Billy was keenly interested in, but that he could not afford or the shopkeeper did not want to sell. (But the shopkeeper might notice *after* Not-Billy leaves.) * Not-Billy puts the staff in one spot before going to bed, but in the morning it is in a different location. For this one, do not call the reader's attention to the movement; don't even let Not-Billy notice it. Just casually mention that he sets it down while describing Not-Billy's actions in one room, and continue to describe additional things he does before retiring. In the morning, be sure you've somehow established what room Not-Billy happens to be in when he picks the staff back up, but without drawing any particular attention to the fact that this is definitely not the room he was in last night when he set it down. Of course, depending on what the "actual" magical properties of the staff are, some of these would have to be modified or abandoned. The quick-drying laundry might be appropriate if the staff has some kind of heat- or moisture-related properties. The floor tile, reflected light, and hat-in-the-breeze examples would all be good fits for any type of divination ability, or for [plot-driven](http://tvtropes.org/pmwiki/pmwiki.php/Main/SwordOfPlotAdvancement) powers. [Answer] Not Billy wasn't sure what was strangest about this, this, well, let's call it a staff. Maybe it was its lack of imaginable purpose paired with the obvious care that must have gone into its construction. Maybe it was the incongruity between its texture, its weight, and the way it sounded when put back on the table. But for some reason Not Billy mostly found himself pondering the fact that someone must have gone to great lengths to paint this thing in the most hideous shade of octarine imaginable. Why would anyone do this? Maybe to protect it against theft? (Not Billy had once tried the same strategy with his bicycle, and it had worked quite well - until Mondrian, the colour blind master thief, came into town and apparently did not mind the olive greenish blue and the yellowish beige stripes. In a way, Not Billy felt relieved at the time, even though it meant he now had to buy a goat for riding to school.) Not Billy considered taking that staff thing with him, but decided against it. He put it back on the oaken table where he had found it. By now he could hardly make out the orange spots that his bleeding nose had left there half an hour earlier. They had been absorbed by the purple surface. When Not Billy stepped into the sunlight and closed the brown door behind himself, he couldn't help feeling that everything was *too* light now, for want of a better word. Had the grass always been that particular shade of green? He suddenly felt the urge to study that object in the sunlight. He felt slightly dizzy now when he thought about it. Hadn't there been something strange about its colour? What colour had that been again? About 65 seconds later, Not Billy left the shed again, this time staff in hand, and not at all dizzy. In the sunlight it was clearer than ever: the only thing that was really strange about this staff was that someone had bothered to paint it in the worst shade of octarine imaginable. By comparison, the grass now looked refreshingly normal in the green sunshine. But obviously this was just his imagination. [Answer] One power I once saw a sword enchanted with in a story, that originally felt weak compared to the rest, only for me to later realize it's power despite it being subtle. The blessing, like all the ones on the sword, was refereed to by a single word adjective, I think it was something like 'calm'. The idea is that the weapon helps to calm it's wielder, prevent them from panicking or acting in a frenzy, instead letting them think calmly and make simple, precise, focused movements. It felt weak, until I remembered what *real* combat is like. Even a professional has a hard time staying calm, and it's hard to keep track of everything going on in a battle to decide where you need to be and how best to help without tunnel visioning. A simple magical assistance, to help you stay calm, focused, and aware of your surroundings in the heat of battle can be a huge boon to anyone, even the most skilled fighter. If not-billy is not a seasoned veteran this sort of blessing is even more powerful. It will help him focus and fight when in reality most would freeze up, panic, or fun in a fight. It can justify how a non-veteran manages to focus on fighting. Even if he is a veteran he would be able to keep his mind aware of things around him, so he could notice other attackers, better plan out his next attacks while parrying the current, and plot reason about his opponents fighting style and weakness during the heat of combat. From my sparing experience, and even gaming experience, I will tell you that is still a pretty strong force multiplier This is also offers lots of foreshadowing options for it's power. Say not-billy is a trained fighter but with limited battle experience, or wasn't even all that trained originally, he may be shocked at how calm he is in a fight. Later when he doesn't have the weapon he may find himself less calm, unable to focus and plan etc, which can be a hint to how to staff was helping him. It also lets him be cool in a way. If it just made him an awesome fighter that would be kind of cool, but ultimately he only wins because his staff was super powerful. However, if it helps him stay focused that may allow him to think and plan out all kinds of unique fighting techniques, using the land to his advantage, tricking someone into leaving a flank open, noticing a character has a tell he can use to anticipate an attack and exploit the opening etc. The character couldn't do it without the weapon, but he still has to be smart and intelligent to take advantage of it. The weapon supports him, but he wins with his own skills not just the weapons. This could suggest a whole class of similar abilities, ones that focus more on enhancing the user in minor ways rather then doing anything flashy. Maybe he is more tolerant to extreme temperatures or hunger with it (to help him survive in the wild better), and has subtlety enhanced senses to help him hear and spot ambushes easier. Another useful effect would be that it boosts his stamina. Real battles are short because you wear out quickly in any fight. It boosting his stamina would help justifying his doing all the things a hero does in a story and really shouldn't have the energy for. I would also give it *very* weak healing power, the sort that doesn't fix a wound immediately, but helps you heal up just a bit faster and, more importantly, recover from injuries that would have done permminate harm with enough time. But the healing is very minor and takes days to really add up, this could be tied in with the stamina easily, the same healing powers are what help you keep going by healing all the small wear and tear on your body that exhausts you. All of these can be subtle enough that no one would notice them at first. As an added bonus they work with genre expectations. Everyone expects the hero to not freak out in combat, to endure things no one really should, to keep fighting with heroic will power. It's subtle not just to the user but to the audience because it grants all the powers we just presume a hero should have, even though realistically no human does. That makes the reveal that much more interesting because of how well it lampshades our own biases. All you have to do to make the staff powerful is to show [reality ensuing](http://tvtropes.org/pmwiki/pmwiki.php/Main/RealityEnsues) for everyone who isn't your character in the story, they can't chase him because they get exhausted to soon, they freak out in a fight and use bad tactics because their afraid etc. You can sort of deconstruct the very expectation of a hero if you really wanted to. The final 'reveal' can be as simple as finally realizing that no human should be able to do all the things your hero is able to do, combined with his noticing how he is always more afraid and feels less confident without the staff in his hand. Once it's expected it can be tested, for instance by testing his senses when holding and not holding the staff to prove that he can better make out things with it, even if only subtlety. If you want more ways to help reveal it have him get a sense of 'ease' when he is holding it, originally justified as his feeling more comfortable being armed then unarmed, but later explained as the 'calm' effect taking over. The staff would likely also be magically protected from breaking or dulling, so he could easily notice that it never gets cut, or burns, or otherwise is damaged when it really should be. Another way to reveal it is to have the staff be powerful when used for/against magic. Imagine a powerful mage cast spells on his own staff to enhance himself. The staffs blessings were all useful effects the mage needed in his daily life, not directly tied to fighting with the staff since the mage didn't fight by hand as often. However, the staff could have one or two additional magical effects that not-billy wouldn't notice at first but are indisputable when they finally come up. 1) the staff is powerful channeler of magic, which the mage used to, you know, cast spells. Not-billy isn't a mage so this isn't useful, but perhaps others may peruse him for the staff because in the hands of a mage it's even more devastating. 2) The staff is powerful at dispelling or breaking magic rather then casting it. it can protect not-billy from magic attacks made against him, perhaps by channeling the energy to the ground. Until Billy gets in a magical fight he wouldn't even realize the staffs ability to dispel magic or break enhancements, but once that happens there is no doubt of it's power. [Answer] **Its weight is a bit off**. Either it is too light from what you'd expect or too heavy. **Durable / Resistant / Unbreakable** The staff simply never blemishes, is unscathed after a hard hit, looks like new, always. Honey or mud would never stick in it. **Has physical properties it shouldn't** Think of a piece of wood that acts like a magnet or, to be cliche, if you throw a piece of metal into the flames, it is quite cool when you touch it immediately after retrieving it [Answer] I think the best way to utilize the "subtle" approach would be to have characters inform the actions of the staff by way of verbal comments, RP, or desires. In some ways (where feasible, it can't be too flashy after all) when a character wielding the staff expresses a verbal interest in something, the staff can start to shift reality toward that end. After a while characters may start to see a cause and effect. Example: A caster wielding the staff says something like, "If only I'd prepared an extra casting of fireball today instead of conjure bread." You can just retcon the spell slots. A perhap better example: "Man I'm pretty weak right now I really hope I make this save against poison." They roll you have the staff provide a circumstance bonus (in secret) to their roll. [Answer] *a set of subtle abilities for the wielder to gradually discover that make them realize there is something unnatural about the weapon.* Some people have already given more specific examples, but the more general way to put it is to slightly adjust your character's sense(s). Even if all they notice at first is "*it feels good in my hand, it must be amazingly well balanced*", eventually they either catch a change in their own perceptions or the staff goes slightly against their expectations in some way. They start to catch little things they wouldn't have noticed before. They seem quicker or stronger, or more precise. They somehow hear a whispered conversation that they shouldn't. However, each time it happens the character thinks they are just lucky or "on their game", or they don't even notice until someone else points it out. --- *a way of establishing the weapon's/device's provenance that would be gradually revealed* Lore-wise, stories of a great hero wielding a fantastic staff could be littered about. But the staff of legend looks all fancy and amazing, and your character's staff is just a plain staff. Stories do tend to be embellished, or you could have some other excuse. You could also have the staff *itself* slowly reveal itself to someone who it likes. Maybe it can actually talk and stuff, you know, if it feels like it. Maybe it first talks to the character when they are sleeping, so it is taken as a dream. Or maybe it isn't actually self-aware, but it does still slowly tell the wielder its history or abilities in some way, just as part of its magic - subtly leading them to pieces of its history. [Answer] The wood of the shaft has subtle carving on it. The more you examine the carving the more detail you see in it--upon close inspection the carving is more intricate than one could expect to be made on wood and yet it looks pristine. Upon enough inspection you realize that the carving shows any special powers the weapon may possess. Over time you notice that the weapon does not grow dirty as you would expect. [Answer] As far as a cursed magical item is concerned I've always liked curses you can never seem to get rid of. Say, that ever since you picked up the stick you find that people shy away from you a bit... mostly because you smell like rotting flesh to them now... and you realize that no no, it's actually not you it's the stick. So now you toss the stick in a lake to get rid of it, but the next morning, you wake up only to find the stick is still there beside your bedroll. So you burn the stick to get rid of it. You watch it burn and turn to ash, the stick is gone. But the very next day, a friend of yours gives you a stick as a gift because she knows you like sticks, and it happens to be the Exact same stick that you know you burned the night before. No matter what you do, it always comes back, it is always there, up until you find a way to break the curse. [Answer] I think the most subtle way would be trough effects on his personality and attention, in ways you wouldn't connect to the object, but the correlation between gaining/losing those traits and gaining/losing that item finally convinces him that it is actually the item that has this effect, and he starts to explore the properties further, learning about its special magical properties. For example: > > The sun was already nearing the horizon, but he still couldn't see the city. He slowly lost the hope that he would reach the city today, so he likely would have to sleep in the free space. He didn't look forward to a night with basically no protection from the wild animals and the not much less wild robbers who made trouble in this area. He tried to motivate himself to go faster, but he simply felt too bad to actually accelerate his steps. So he slowly walked on, with his eyes down to the floor instead of to the horizon. The view of the horizon, with the city not in sight, was too depressing. > > > As he walked on, he suddenly noticed a staff lying in the mud. It wasn't a particularly pretty staff, but for some reason it caught his interest. Maybe it would be useful to fight animals or robbers, he thought, although the staff didn't actually look as if it would survive more than one strike. Anyway, he picked it up and started to wipe the mud from it. > > > The concentration on cleaning the staff seemed to have helped his mood. Although he had lost even more time by doing that, his situation to him didn't look as bad any more. After all, this land was full of hills, so the fact that he didn't see the city yet might just mean that it was hidden behind one of the hills. And even if he did not manage to reach it, he now had at least a weapon to defend himself. It might not be the best weapon in the world, but anyway, it should help. > > > He started to walk again, now faster than before, and with his eyes fixed to the horizon. And suddenly he noticed a dark spot there. Was that the city? He looked closer: The spot was still very small, but he now could clearly see two upwards spikes. That had to be the famous two towers of the city! He obviously was much closer to the city than he had thought. Had he not continuously looked on the floor instead of the horizon, he probably would have made out the city much earlier. > > > But then, in that case he would not have found the staff. But he wouldn't need the staff anyway, as he now was sure he would reach the city before sunset. But anyway, for some reason he considered himself lucky to have found that staff. It was illogical, but well, feelings were illogical. > > > Later on he can lose the staff, and his mood gets worse; but again he has a perfect explanation for that change, unrelated to the staff itself. And when he finds it again, his mood again starts to get better, but again this has a perfectly plausible explanation. But over time he starts to draw a connection between his mood and the staff, at first not taking it seriously, but over time he gets convinced that it is really the staff that's responsible for his mood change. That's the point where he starts asking himself how the staff could affect his mood, and while researching this question, he learns about the magical powers that lie in some items, and how to identify and use those powers. [Answer] I would like to propose two quick ideas: 1. One of the issues other answers have discussed is the "how do we get NotBilly to hold on to it long enough to notice the subtle clues" problem. I propose to have NotBilly having it *be* the subtle clue. NotBilly runs across this stupid staff way more than he ought to, really -- first it's in the grip of the orc he kills in a desperate spot. He leaves it with the orc, but some enterprising hawker offers it to him again at the market -- 100% genuine Dwarf-fashioned wood, grown in the finest groves, you know! -- which he turns down as it is obviously too plain to be dwarven work. A friend he bumps into later had been conned by the hawker, and offers it to him. He refuses, then sits on it accidentally when taking a carriage to the city center for the yearly census -- seems somebody had left it behind that day. And a dozen more coincidences slowly cause him to be curious about this stupid recurring theme. 2. Turn the problem around: make the artifact manifestly magical, but stubbornly useless. It is emitting sparks and a purple glow, and when you get near your hair turns blonde for a second. If you hold it, instructions magically appear -- unfortunately, in the lost tongue of \*\*\*\*. People have been trying to get it to do something actually useful for hundreds of years without success. At this point, it's such a joke that nobody really cares about it any more. But it's indestructible, so it's no surprise for NotBilly to discover it completely intact on the side of the road, where its previous owner finally got fed up with it and threw it on the ground in frustration during a long car trip. And of course, NotBilly never discovers its true power; he only discovers some side effect of its true power that happens to be not 100% useless in 100% of situations. (It puts me in mind of that thought experiment about our nuke-surviving descendants discovering a radio, and figuring out that it electrocutes them when they're in the bath, but never really working out what it's actually good for.) [Answer] The first few ideas that popped into my head: 1. **Only the conscious mind needs magic to be subtle.** Whenever Not-Billy leaves the staff leaning against the nightstand next to his bed, he has the most amazing dreams. In these dreams, he is a warrior of superhuman skill, wielding a staff of breathtaking power. His magic is not bound by the shackles of subtlety that limit its possibilities in the waking world. In dreamland, he is free to unleash all manner devastating effects upon his foes. It doesn't take long for him to realize that these dreams are not his alone, and their impact can be very real... 2. **It always turns up.** The first few times Not-Billy encountered a staff like this (lying on the ground, leaning against a park bench, sitting in the window of a junk store) he barely noticed it. After a few more encounters, he began to pay more attention and to remember the details. These staves all seemed to have the same gnarls and knots, despite being of apparently natural origin. But what kind of tree could produce such similar looking branches? And why had it become so commonplace to find them lying about? Slowly, the strange truth began to dawn on him-- these were all the same staff! Somehow, wherever Not-Billy happened to be going, the staff always managed to get there first. How did it predict his destination, and how did it relocate itself without drawing the attention of anyone but him? In a world where magic must appear mundane, that level of subterfuge could be a valuable tool indeed... 3. **Animals are often aware of things that are beyond human perception.** The power of the staff is one such thing. When Not-Billy sets it on the ground, bugs, lizards, and other creepy-crawlies emerge from their hiding places and scatter. When he brings it home, his dog hides under the bed and refuses to come out. Or maybe animals are attracted to it. Squirrels, songbirds, and other normally shy critters have no fear of Not-Billy when he's carrying it around; they may even perch on his shoulder now and then. And when the time comes, some of their more predatory kin will prove to be very handy in a fight... [Answer] There are a lot of good answers already about figuring out that it is magical, but I am not sure they are really fully addressing the question of finding it. If you want to be subtle, both for the readers and for NotBilly and his/her companions, then a very plain staff is a good starting point. It can even be visibly plain, but gradually shift over time, or look different in a certain light, but on the surface it should just look like a normal, utilitarian wooden pole that can be used for holding things up or hitting someone, just like any other length of reasonably sturdy wood. **Finding the staff** It should be found at a time when something like that is needed, maybe not precisely a wooden staff; it might just be the best option available at the time. For example, our hero and his intrepid band stumble across a small group of bandits and end up driving them off, but one of their party is injured. The injury is bad enough that they need to make a sledge or stretcher to carry him, this pole that was leaning against a tree is just one of the pieces of wood used for the structure of the sledge, and other thing scavenged from the bandit camp get more attention. Perhaps there is a richly-lined and warm fur cloak or a supple and well-balanced bow and a fine quiver of arrows. After getting to civilization and taking the injured person to get medical attention, the cloak, ropes used in the sledge and this staff simply get packed away with the rest of the gear. Later, someone (the bandits, wild animals, whatever makes sense) attacks the group at a time when they least expect it, NotBilly is near the gear and unarmed, the sledge-pole is nearby, he uses it to protect himself, and the next day, there he is, using it as a walking staff as they go. If NotBilly is the type of person who normally wields a sword, it would be unnatural for him to suddenly switch to a staff, even if he likes its balance and it "just feels right" in his hand; as soon as his current use for it is over, he would tend to swap back to the sword. It might be easier to have a non-combatant develop a flair for combat with a staff. On the other hand, having a sword-wielder gradually stop going for his sword and finding that he's reaching for the staff might be a clue that something is going on. At first, perhaps he tells himself he needs the reach on a taller opponent, or perhaps he doesn't have time to drop it and grab for his sword from the sheath, but later he leaves the sword untouched at his belt, and later he finds it is getting in the way and he leaves it in his pack. **Abilities** As noted in prior answers, durability, balance, and improved skill when using the weapon are very helpful here. It could also resist NotBilly being disarmed -- he is able to keep a grip even in circumstances where he would be expected to drop it or have it knocked out of his hands. On the other hand, he is surprisingly adept at disarming other opponents. He might develop an uncanny knack for subduing an opponent without causing major bodily harm, either destroying the weapons of his opponents or knocking them far out of reach, or managing to stun or knock someone unconscious without killing them. Blows that might otherwise be expected to break bones don't, but the opponent still stays down. Consider that a wooden staff is often the classic weapon of peace-loving characters, so perhaps this is a weapon that subdues aggressive instincts and increases protective ones in anyone who is touched by it. Perhaps it needs a flesh contact to work, so wearing gloves causes NotBilly to lose his new skills, and hitting someone where they are armored doesn't spread the pacification as well as knocking them on the ear or a bare ankle. **The staff chooses to be wielded** The staff has a personality that has grown over the decades or centuries since it was made and enchanted. It has an empathic connection with its bonded owner and will influence the user and be influenced by him. When out of the owner's hands, it is a normal staff, and it tries to get back to its owner. When it isn't bonded to anyone, it travels in search of a new person of the right frame of mind. It exerts a subtle influence to various people to pick it up -- either because it thinks they may be the next one, or because it thinks they will take it to a good place to find the next owner -- and they carry it for a little while until it exerts an influence for them to forget about it. Most don't ever notice. They needed a pole or staff at the time, then later they no longer needed it and forget where they left it, if they even think about it at all. And if they can't quite remember why they came to wherever it is that they ended up, it certainly wouldn't have anything to do with a bit of wood. It may have imprinted memories from its past, or even from past users, and it may share these after the bond has matured, or through dreams. [Answer] There are plenty of good answers, but I really feel that explicitly coming up with details such as humming, weight or warmth are likely to give away to the reader this is item has a special meaning. **Motivation to carry around**: As non-Billy just found this by chance there better be a good reason for him to carry it around at least to get started with, maybe he took the staff from somewhere to fight a enemy, got outnumbered and with the staff as the only weapon he just kept it for security. Maybe he could have tossed the staff at an enemy blocking his path and the staff was resilient enough to knock him down you can make it look like a lucky strike but non-Billy could go like "Well I guess this piece of stick works" and keep it in his way out of the trouble. **Make other people recognize the item**: He could be granted entry in places with no apparent reason, because guards are educated enough to tell the staff is magic and therefore non-Billy should be a important person. They don't need to mention it. In a world wizards are detectives non-Billy could wander into a crime scene with no one stopping him just to realize he was tress passing and then rush out of it. **He could meet former owners**: Owners don't need to have realized the staff was magic, and maybe go like, "Oh I that staff remembers me of my childhood, my grandfather used to have one pretty similar to that, one day he went out to walk and aliens contacted him", seems like just a crazy guy story, probably not relevant. Maybe those conversations can get interrupted by seemingly mundane events. Non-Billy could just get distracted with the mumbo-jumbo the guy he just meet it going through just to find out latter that person actually told him a valuable piece of story that connects with things that happened to him, which so far seemed like sheer luck or lack of. **Unusual utility**: It starts to rain as non-Billy goes up a mountain, he grabs the staff and goes wherever he needs to be. When he goes back home he needs the staff again for any reason (kill a spider, grab something in a high place) so he goes to a placeholder where he usually leaves it, but its not there. Oh of course, he took it to the mountains so he must have left it in the backpack, but wait, I don't quite remember taking it from home to start with, I guess I'm getting old. Maybe he falls in battle and the only weapon that drops nearby him is the staff, doesn't look like much all by itself, combat does not needs to be flashy, just to narrowly save his skin **Repetitive behavior**: The staff could always be rolling though the house, like if hard to be kept in the vertical when unattended, which would come as an inconvenience to the wilder, it could be attracted to something rather common that would make it seem like is always stumbling around when left by a wall. It could be attributed to one of the ends being slightly heavier than the other, but non-Billy can never tell which side is which before it actually falls down. Once its picked up and put in place again it doesn't starts to roll around so soon again, because, well its magical it behaves like we want it to behave x) leaving the idea that non-Billy got the right side now. Maybe the interruption caused by the sound of the staff falling can be combined with other events in order to help or undermine the character. For instance the staff falls to the ground right beside a door, not Billy goes to pick up the staff and place it now with the heavier side downwards, as he approaches the door someone opens it and hits Billy All those can be used to establish a base from where the character might start to get suspicious about the staff. Hope I could help [Answer] I'm going to agree with carvings being on the staff. I suggest runes, or something similar, that appear meaningful, but require massive research or the like to glean any sort of meaning. Any normal looking object with strange writing on it that no one understands is likely going to have some significance, but won't be immediately clear, hence the epic quest to uncover the potential locked within. This would be similar to the Forgotten Realms stories about Arilyn Moonblade and her sword that she knew was magic, but had no clue what abilities it actually possessed. [Answer] Here's an idea... NotBilly doesn't know the staff is magical. All he knows is that he has been improving in his fighting skills and has gotten quite good over the past year... Then he gets into a battle and has to use some other staff and does very poorly. Maybe then he will realize the staff is magical, or maybe he won't but the reader will. :-) [Answer] If humans can also be magic in this world, you could bring it to an appraisal specialist with a magic detecting ability or something similar. [Answer] The weapon has a word carved into it, maybe crudely. This word is actually the weapons name, but it is a short ambiguous word and not obviously a name, like 'north', 'knock' or 'river'. In use it handles lightly but is surprisingly effective, although this may be an effect of the hard metal ends. It can tell the difference between a friend and an enemy. An blow to an ally, accidental or otherwise, will be felt but will not be as wounding as to an enemy. It will take a long time to realise this. If it is taken and used against its rightful owner, the blow may not even land - something else like bad luck will befall whoever has taken it. The weapon begins to assume an identity, and to be associated with the word carved roughly on it, with it often being referred to by that name, because it seems natural to do so. A person begins appearing in dreams, at first nameless, over time it becomes clear that the person is either closely associated with the weapon, or maybe a dream manifestation of the weapon itself. At this point there is scope for dreams to start explaining the true history and nature of the weapon, and the full extent of its powers. [Answer] It's probably not all that realistic to do, but I was immediately thinking of swapping him an unfair die, one that is missing several low numbers and has duplicate high numbers instead, but distributed in a manner where you cannot see more than one of the duplicates from any given angle. But maybe there are some other means of messing with the overall game mechanics when the item is in play? [Answer] Some thoughts ... You might introduce it as being different during a quiet scene where Billy is polishing it. He starts paying attention to the subtle patterns of the grain. The grain patterns begin to ... waver ... as if seen through heated air. He blinks and the pattern is back to normal. "Crom, I need to get more sleep." But over time he starts using the staff as an aid to concentration or meditation. Later he feels oddly reluctant to part with it -- say when entering a common house which checks weapons. Still later he can use it for something that should have broken it... Say he blocks a massive overhand axe-blow with it. The impact drives him to one knee, but he notices later -- again, with the polishing -- that it is not scratched. His friends notice that he "grooms" his weapon a lot. Depending on the tone you want to take it can be jovial ("Oh for Mitra's sake, Billy's got wood again") or concerned. "Billy ... are you alright? You keep staring at your staff...". This could lead to a discussion of how patterns (woodgrain, fabric weaves, etc) can be cursed and draw people in. Billy is a little defensive, and realizes it. Now he wants to know the provenance of his weapon. If this is a named artifact, work in the name somewhere. "Ha. Billy, remember when we were lads and we'd play knights? You always wanted to play Rynn and his staff Lament. You'd wave it about and dozens of ogres would 'fall to their knees, repenting of their deeds'." Basically, you need to build the backstory for Rynn's Lament, just like for a character. Und so weiter... ]

[Question] [ If a sword were to be swung horizontally, through the torso of a human being, how fast would it need to be to not have blood on it after the swing? Assume the sword and its user are together able to cut through all of the proper bodily organs and bones in a single strike. Assume a well-forged steel blade. [Answer] **Speed Not Required** Give your sword a [hydrophobic coating](https://en.wikipedia.org/wiki/Ultrahydrophobicity) and it will never get any blood on it. The coating repels liquids, causing them to bead up like water on a lotus leaf and just run off. Bonus it stays nice and clean. **Edit:** A blade made of steel does not mean that It cannot have a coating that makes it repel blood. Furthermore, the surface geometry of the blade may be altered to give the steel hydrophobic proeprties. This [laser](http://www.rochester.edu/newscenter/superhydrophobic-metals-85592/) can do it to a variety of metals. [Answer] Not only is speed not required as per Joe Kissling's answer but speed is not able to keep it clean, either. The sword will be pushing through blood as it cuts, it's impossible for blood not to get on the sword. Thus keeping it clean means either a material that blood will not adhere to, or a speed in which the air movement will scour the blade free of blood. Consider airplane wings--even going hundreds of miles per hour is not enough to sweep ice from the wings despite a smooth surface. Ice doesn't bond all that tightly. The airline industry combats it by spraying on a coating (note that the coating also doesn't get blown off) that lasts long enough for the plane to get above the threat zone. While this doesn't give us an exact answer it shows that we need a speed **far** beyond what muscles can deliver. My gut says the required speed is supersonic (which means a nasty sonic boom from the sword) but I do not know. [Answer] It's the stopping speed you're after. Say the swing speed is a bit better than a golf club's speed swung by a pro-golfer. We're looking at 100 mph or 44 m/s. If your hero/villain brings the sword to a standstill after the cut in half a second, the g-force will be ~9 Gees. I'd say it's enough to propel the blood off the sword (testing required). [Answer] To elaborate on anon's answer, there is a motion called [Chiburi](https://en.wikipedia.org/wiki/Chiburi), excercised by the samurai. In movies it is a quick flick of the sword that removes blood, but in reality the sword still requires extensive wiping with a piece of cloth. [Answer] Okay I tried to relate kinetic energy of the sword with the temperature needed to boil blood (which would mean that the blood boils off the sword as it's cutting through the victim, and hence no blood on the sword). I don't know if I did this correctly, as I couldn't find a nice way to relate kinetic energy and temperature, but I found that the sword would have to be going 409 m/s (or 914 mph). --- Edit: Here are my equations used... $<KE> = <\frac{1}{2}mv^2> = \frac{3}{2}kT$ Which is average kinetic energy equals the average of one half the mass of an iron atom times its velocity squared. Then that equals three halves of the Boltzmann constant times temperature. I used: * $m$ = 9.27E-26 kg (atomic mass of iron (since swords are mostly iron)) * $k$ = 1.38E-23 J/K (Boltzmann constant) * $T$ = 374 K (temperature at which water boils plus a little bit to account for the salt in blood which raises its boiling point to about 374 K) Plug everything in and solve for $v$. That yields $v$ = 409 m/s. To see what that compares with in terms of the sword as a whole's kinetic energy, I used the kinetic energy equation again, only this time using this velocity times the sword's mass ($m$ = 1.4 kg, mass of a katana). I got 117,000 Joules of energy. Which feels kind of low to me - that's like a car hitting you on the road - but maybe I'm not relating these equations correctly. [Answer] The speed of a sword can, in fact, affect how much blood is left on it. But for a sword to have no blood on it whatsoever, the sword would have to be faster than the speed of the blood dripping onto it while it's in the human body. the only speed at which this is possible is the speed of sound. 334 meters per second. If the sword breaks the sound barrier 1 millimeter before hitting the target it would rip the body and the sword would only continue behind the massive force of a broken sound barrier. The sword would simply act as a device to break the sound barrier and the use the explosion to cut the target in half. If any human could achieve this they may as well use something else made of steel like a crowbar or a steel pipe. So if you want to split someone in half and not get the tool you use dirty. Acquire superhuman strength and break the sound barrier next to your victim. (i think I made a new superhero ). [Answer] OK, a theory that might actually be close: Assumption: All the blood is equivalent to a mass of water. Further assumption: If struck above speed of sound in water (which is ... high!), anything striking it will not be good at selectively displacing part of it to make way, and try to accelerate the whole mass, which will appear close to one solid object, which gets effectively shattered into two (heavy and hard to accelerate) or more (flying off at an angle) pieces in case you manage to cut through it. Problem: It is unlikely that a metal edge will stay intact after that kind of impact. Since the displacement needed for a blade to pass is very small compared to eg an unlucky person hitting a body of water flat, a lower speed impact is likely to displace some of the liquid as a liquid and accelerate it together with the cutting edge, staying on it. ]

[Question] [ An empire spanning the globe has a military force trained and equipped for the temporary impairment of combat forces, such as sleeping gas, shields and nets. The empire is by far the most technologically advanced on the planet, with late-Victorian technology (including armored vehicles) available in abundance. Would such an army be effective in protecting the country? [Answer] # War and battle is not about killing... ## Summary / tl;dr Yes, this military will be effective, because you will write that it is. Your job as the author is to make it **credible**. ## ...it is about *control* This is not even a platitude: war and battle is not at all about killing people, war is about **establishing and/or keeping control**. When you have control you have won the war. And what is it that the belligerents want control over? * **People**, because people can do work and pay taxes; they **produce value** * **Resources**, such as mineral deposits, manufacturing, farmlands * **Areas**, strategic locations from which you can conduct operations, or use as transport routes Now granted, it is "easy" to win control by simply removing someone that stands in your way, for instance by killing them. But killing is not at all **necessary** to win control. In lieu of outright killing your enemy, you need to either **deny** them the control they want, or make them **unwilling** to exert control over your people, resources and areas. You said that this nation is by far the most advanced nation on the planet, to the point of having self-propelled armoured vehicles a full half-century before everyone else. This means they have two things with which any defensive force can win the war: **mobility** and **communications**. ## 1. Winning the information war means: always ahead of the invader No matter what the invaders do, it appears that the defenders **know** — as if by magic — where the invaders are going to turn up next, and they always seems to be adequately prepared for this. The "magic" in question is things like wired and wireless telegraphs, used by a **vast** network of observers, informants and agents. While the invader is on foreign soil, they have to rely on messengers to deliver physical messages, and all attempts at establishing instant messaging like a telegraph network is always thwarted by the defenders. ## 2. Nothing to control Whenever the invaders show up at what they thought was a significant location, there is nothing there to control. The civilian population has been evacuated and relocated with astounding efficiency, the advanced machines that your nation is famous for have either been moved away or dismantled and hidden well, the invaders find mine shafts filled with water and no way to pump it out, the granary cashes remain empty or simply never found. With few people in this defence force tasked with battle you get a lot of people available for preparations and transport. And even more people available to train and drill civilians in how to quickly and efficiently be relocated, out of the way from the invaders. ## 3. Disrupt logistics routes > > "Amateurs talk about tactics, but professionals study logistics." > > > General Robert H. Barrow, Commandant of the Marine Corps, 1980 > > > No invading military has ever been able to maintain control if cut off from their home-land. Your nation's defence has specialised troops that excel in messing up supply routes for the invading enemy, denying them food, resupplies, and — maybe worst of all — a way back home. That impressive iron bridge they invaders passed over yesterday? It is now a pile of mangled beams at the bottom of the ravine. That nice paved road through the marches? It got flushed away by an unnaturally appearing flood that soaked that whole area and made the roads completely impassable. The invaders may get **into** the country with relative ease but once there the initial victory rush will be replaced by being bogged down in a logistical nightmare. This point and the one above would [not be the first time in history](https://en.wikipedia.org/wiki/French_invasion_of_Russia) this has happened. ## 4. Psychological warfare > > — Hey, did you hear what happened to the captain's previous command? > > > — No, what? > > > — They disappeared... all of them. He went to sleep one evening in the camp... the next day... **poof** they had all vanished, like magic. Only he and his tent was left standing. > > > — You are pulling our legs... > > > — Try, ask him... see how he freaks out. > > > Sleeping gas and nets? Specialised in rounding people up and taking them captive? You nation's defence will be **experts** in cooking up all sorts of "mysterious" events that — when re-told by influence agents hidden in the invader's ranks — will demoralise the invaders really quickly, especially when cut off from home as mentioned above. Add to that effective propaganda, outright bribes of entire military units, impressive — and frightening — displays of technological aptitude and skill, and you can soon have invaders that shivers at the kneecaps at the thought of trying to deal with this enemy. One of the biggest demoralising elements of this is that the invaders are simply is not prepared for this. They have trained for **traditional** battle, of setting up face to face in the field and then clashing together. Nothing(!) prepared them for an opponent that behaves like this; they are not being out-battled, they are being out-manoeuvred. The final blow is when the diplomats — with a confident smirk — convey the message: "And if you think *this* is bad, just imagine what happens when we decide to use *force*. I advise you to go back to from whence you came while you still can. Good day gentlemen, ma'ams". ## 5. The ultimate ace up the sleeve: author's say-so In the end it does not come down to whether a non-lethal military would be effective in real life or not, but whether you as then author can make it **credible**; if you can make the reader [**willingly suspend their disbelief**](https://en.wikipedia.org/wiki/Suspension_of_disbelief). This military — in your story — will be effective because you as the author will say that it is. The only issue is if you can get the reader to accept it. [Answer] No. In the words of General Georges Sada, "The purpose of a military is mostly to be strong enough that you never have to use it". A non lethal military fails in this test on several fronts. 1. When the other guy is shooting to kill, you lose people just trying to get close. He can choose to simply destroy your cover indiscriminately with one big bang from a distance, while you're constrained to get close enough to touch on every encounter. Your losses on every engagement will quickly wear your military to nothing while leaving the enemy at nearly fill strength 2. The majority of rounds fired in military operations are cover fire - they aren't intended to hit anything, their only role is to keep the enemy from shooting at you. If the cover fire is non lethal, the enemy will take more chances because a hit doesn't cost enough. 3. Non lethal (or more properly less lethal) weaponry can often be adjusted to. People who have been pepper sprayed more than once will often learn to continue through the irritation. Tasers aren't always effective. People differ in their reactions to anaesthetic gases. [Answer] ## Yes... I second all of MichaelK's answer. Killing, while common, is not inherently necessary to win a war. I will add that historically it was far from uncommon for military units to surrender with minimal violence once they knew they were outmaneuvered. This was particularly common with mercenary units during the Renaissance but you see it all throughout history when you are dealing with professional soldiers rather than amateur militias. Logistics are also of vital importance in any campaign expected to last for more than a single battle. A non-lethal military can be fully effective so long as it has other ways of achieving **control**. ## But... I'm writing separately rather than only upvoting MichaelK's answer because I think he is overlooking the difficulty of having believable, effective, non-lethal techniques using roughly Victorian era technology. It is so difficult to create combat effective non-lethal weaponry that the term has fallen out of use in most military and law enforcement circles in favor of "less-lethal" weaponry. Using any type of "knock-out" gas on a group is likely to kill at least some of them while risking leaving others at reasonably high levels of alertness and effectiveness. Getting the dose right on that is difficult which is part of why professional anesthesiologists exist. CS gas and tear gas have relatively few casualties, but they do not work well against an organized military force and are mostly used to disperse crowds. Tasers are probably one of our better ways to incapacitate a resisting person non-lethally, but there have been instances of them causing [death](https://en.wikipedia.org/wiki/Taser_safety_issues) and other instances of them being almost ignored. Nets work well against a single opponent, especially if you only need to incapacitate them briefly. They were famously used by gladiators in Rome who, despite some TV depictions, rarely wanted to kill their opponents. But incapacitating a unit with a net would be hard, especially if you need them to stay that way for a while instead of being able to extricate themselves. Other less lethal technologies such as active denial systems based on sound or microwaves are likely out of reach of Victorian Era technology and again are more about crowd control than facing an organized military. If you are writing a story and want verisimilitude, the hard part will be selling technology that is both effective and non-lethal. This changes of course if you add magic or science-fiction style hyper-tech which would allow you to almost hand-wave this problem away, but if you stick to Victorian era technology it may present challenge in keeping it believable. [Answer] Of course it could. There are many ways that they could still be a force to be reckoned with. There is a historical precedent for most of it. ## The main role of the military is a deterrent The military does not exist solely for invasion and conquest. It’s main role is for bargaining and actually using it is a last resort. If an international dispute can be settled by diplomatic means or economic agreements, then that is still preferable for both parties than a confrontation. Even during the Victorian era, diplomats played an important role and there was a lot of communication between leaders to attempt to avert conflicts. A non-lethal military operation could still be disastrous for a country with territory seized, soldiers captured, and commoners turned against their own government. Especially if this Empire is vastly more advanced than neighbouring countries, then a conflict with it would still be detrimental as would rebellion within. ## People don’t fear death that much Lethal force isn’t that effective as a deterrent. A military intimidates another nation and its government but doesn’t stop individuals stepping up to confront it, eve in the face of insurmountable odds. In the face of ideological differences, the fear of death can be overcome. Many people still stand up to tyrannical regimes even if they use lethal force, torture, or other human rights violations. For some, Martyrdom is even desirable or glorious. People still commit crimes in the face of the death penalty. Countries that use the death penalty don’t have lower crimes rates than those that have abolished it. Death is an abstract concept that we haven’t experienced so it doesn’t function that well as a deterrent. We all think, it won’t happen to me. Close calls are known to result in courage among the survivors. This was evident among the survivors of the London Blitz, it strengthened their resolve to continue to support the war effort. It was not effective to break the morale of the everyday people. Dropping bombs on a country doesn’t typically convince the local people that you are there to liberate them. We’ve seen more technologically advanced militaries fail from Afghanistan to Vietnam because they didn’t understand the importance of how they were perceived by the local people. An military employing lethal force is not necessarily effective and some cases the resistance to them only grows as more people turn against them. In this respect, an Empire using non-lethal force could potentially be more effective as they can resolve isolated conflicts without being condemned internationally or turning others against them. ## Non-lethal weapons still cause harm A regime employing only non-lethal force is still something to be feared. Many chemical weapons are considered war crimes against the Geneva conventions, even if they are not lethal. It is still possible for this Empire to be authoritarian and incite fear among their own people or other countries. They would not necessarily be harmless simply because they refuse to kill. They can still maim and injure people on the battlefields. They can still capture, imprison, torture, and enslave people. They can still use poison and destroy property. They can still push a region to the brink of starvation and economic collapse by burning their crops and destroying their infrastructure. They can still deploy chemical and biological weapons to cause mayhem and suffering at a massive scale. The decision to have an Empire which does. It use lethal force does not limit the scope what else they can be. Just as countries with nuclear weapons and torture camps can settle disputes diplomatically, likewise an Empire without these can still choose conquest and the violations of basic human rights. These are not mutually exclusive. Perhaps the most interesting consequence however will be the vast number of survivors after any conflict to tell the story. Anti-war sentiment grew in conflicts that draw media coverage and showed the experiences of the front lines. From the poets of WWI to the filmed broadcasts of Vietnam. If there were more survivors to share their experiences, this would greatly affect public perception and the world as a whole (in way that was otherwise not possible without modern communication technology). [Answer] **No, it would not and could not be effective** **Social issues:** Larry Niven's 9th law states "Ethics changes with technology". Applied to this situation - through most of recorded history, human life has been little valued. When infant mortality rates are so high that couples *expect* to lose one or more children before they reach adolescence before injuries and disease reap an early harvest amongst the older demographics - death may not be desirable, but it is considered normal. [Capital punishment](https://en.wikipedia.org/wiki/Capital_punishment) has been routinely practiced by almost all societies, sometimes for trivial offences such as petty theft. It is only in the last few hundred years that increasing technology has led to the economic prosperity has made it financially *possible* to deal with common criminals through imprisonment rather than execution. In short - despite the beliefs of some humanists and/or religious teachings, there would be no social will to outfit a military with non-lethal options routinely. Even riots by a country's own citizens were routinely dealt with through the use of bayonet charges and/or the use of live rounds - see the history of the [Riot Act](https://en.wikipedia.org/wiki/Riot_Act). It would be inconceivable to treat enemy combatants with kid gloves. As noted in other answers, the other social issue with a non-lethal military is that it lacks deterrent effect. If the worst that will happen to your enemies is that if things go badly then they go to sleep for a while - the opportunity to get some extra sleep is generally considered a *bonus* to most soldiers. **Technological limits:** "Sleeping gas" - the use of various gases as a means of general anaesthesia during surgical procedures gradually became more effective throughout the 19th century - effective meaning that the patient was anaesthetised *but did not die*. The reduction in lethality was due to improved methods of controlling the dosage when the gas was applied using a mask held over the face. There were certainly no gases known that could be deployed over a wide area of the battlefield that would a) reliably put humans to sleep; **and** b) not kill lots of them. Regarding defensive measures (to allow the use of relatively short-ranged non-lethal options) - armoured vehicles have significant limitations even today. Early armoured vehicles were extremely slow, unreliable and short-ranged. For personal protection, the type of armour available in the late Victorian era was basically steel plates, an example being that worn by [Ned Kelly](https://en.wikipedia.org/wiki/Ned_Kelly#/media/File:Ned_kelly_armour_library.JPG). (It didn't work out so well for him.) Such armour could not be worn continuously and provides limited protection against military firearms of that and earlier eras. The other issue to consider is that warfare encompasses many settings. In a naval battle it would be almost impossible to effectively use any non-lethal measures against another vessel without precision delivery of munitions that only became moderately affordable in the late twentieth century. The best option for a truly defensive-minded military with a monopoly on late Victorian era technology (assume all other countries are 50+ years behind) is to have a conventional (lethal options) military which can react quickly and overwhelmingly. The empire can achieve this through: * a monopoly on near-instantaneous communications - no one else has telephone networks and few have telegraph * strategic ability to rapidly deploy military forces - vastly superior train networks and motorised troop transport naval vessels * overwhelming naval superiority - no one else has naval vessels that are ironclad and motorised equipped with vastly more powerful and long-ranged guns. Simply being too scary to even consider attacking is a much better way to save lives than getting into lots of fights and relying on dodgy, (possibly) non-lethal options that are beyond the technological limits of the era. [Answer] ### Yes, but somehow it must be effective. Effectively, it would be more like a "world police". How exactly, it depends. Some example: * They might far outnumber any possible enemy military by mass. * They might overwhelm them technologically (for example, bulletproof shields and vests). * They might have a strong, world-wide security service system, gathering data and solving challenges before they could emerge to a visible level. * Or all of these, combined. [](https://i.stack.imgur.com/WZbL6.jpg) [Answer] So, your military does not kill. How very nice of you! But how would you win a battle? You calculate on non-lethal methods to impair the enemy combatants. Congratulations! You just knocked out a few thousand enemy soldiers... But what now? Will you let them go? That would be backbreakingly stupid, they could return to fight again. So you have to imprison them. Fastforward to after you won a few battles: You have a massive amount of prisoners of war, who must be guarded, feeded and housed. These prisoners will drain your ressources, and the danger for prison escapes or revolts is high. Sooner or later, even if your military is succesfull in the field, you will run into massive problems regarding logistics. As cruel as it is, prisoners of war are mostly a small number of the enemy combatants, because most of the enemy soldiers died or fled. The only occurences of large numbers of POWs was when enemy forces were surrounded and surrendered. Result: Even if (and that is a big IF as others have pointed out) your non-lethal military wins a few battles, the number of POWs will crush your logistics. [Answer] Yes, but it's complicated - that's why no one has ever tried to do it in reality. An army can be used on the offensive or on the defensive. If the latter, its more important quality would be the **deterrence factor**, so is, the ability to make other countries not daring to attack you. On the offensive the most important thing is the ability to take control of enemy territory - and negate the efforts of the enemy to regain it. Neither quality requires killing people, but it's harder to do it without killing. Actually, a non-lethal army has many advantages over an homicidal one, which is its ability to win the hearts and minds of the vanquished. When USA toppled down Saddam Hussein's regime in Iraq it might have expected some kind of gratitude and a positive feeling about them in the country. Well, **no**. If you could conquer a country without killing its people - say, releasing the enemy combatants after some time as prisoners - you would find the task of ruling the recently conquered area much more easier. Govern them a little better than they were before and mostly respect the local culture, religion and language and pretty much you have incorporated a new batch of happy citizens to your empire. The deterrence factor should not be a problem, then. If country A attacks your empire, you defeat them and incorporate part (or the whole) of the attacking country into your empire. Nobody will dare to attack you anymore. The problems with a nonlethal army are not strategic, then - you have the upper hand there - but tactical. In actual battles, non-lethal weapons are in clear disavantage against lethal ones. They are usually short-range, are not guaranteed to stop your enemy and aren't scary, so it's unlikely the enemy is going to surrender or flee without fighting. A nonlethal army, to be succesful, would need being (nearly) invulnerable to enemy fire. If you don't kill them, but they can't kill you then your army does not have to fight against the burden of losing lives without inflicting casualties. A certain sense of superiority morals can make your people to sustain some casualties without resorting to revenge, but if your casualties are too high (being too high a really low number) the morale will crumble. Also, the fact that the enemy can't kill your people will make clear to them that the resistence is futile and they are going to be captured if they continue the fight, so they are going to be more inclined to surrender or desert. If they are not really inmortal, at the very least they'd need highly effective nonlethal weapons. If your troops have stunning rifles able to disable an enemy a kilometer away, with 95% success rate or higher, they at least can try to play it safe; keeping the distance, trying to fight outside the effective range of the enemy and not exposing too much. Your weapons must be able to incapacitate the enemies more or less permanently, however, since you can't approach your targets until they are all down. If your weapons can do that, this is in fact an advantage over lethal weapons. In modern warfare usually maiming is preferred to killing, since when you injure an enemy you usually take out three enemies per shoot: your target and two comrades who are going to take him to a hospital. All of these restrictions put you in a scenario where your empire must have an overwhelming technological advantage over your enemies, to the point they can be considered gods. Think about spanish conquistadors in America: they didn't have nonlethal weapons but had they used them the result would have been pretty much the same. Since their armors and horses made them nearly impossible to kill, the natives despaired and surrender, even with massive numerical advantage. The spaniards killed the enemy combatants, but being captured and slaved was equally threathening, so nonlethal options, had they been possible, would have worked pretty much the same. [Answer] **It can work, but only with some meaningful edge** The military is not a killing machine, believe it or not. The military's purpose is not to kill the other guy. The military's job is to accomplish an objective important enough that they are permitted to leave the realm of civilized life in order to achieve it. To describe them properly requires a double negative of sorts. It's not that they will kill to accomplish a goal; it's that they are not bound to not kill while accomplishing a goal. If you look at modern American combat, they do indeed operate with tremendous bounds. The rules of engagement can be tremendously frustrating for a soldier. Limitations on how one is permitted to return fire when an RPG firing enemy hides behind women and children can test the patience of any soldier. But if anything, it does show that a military can operate in heavily restricted rules of engagement. Non-lethal is merely one such heavy restriction. They accept these limitations because we can indeed accomplish the objectives within them. It may cost more (and we do hate how much the military costs), but we can accomplish it. However, put the military in a more symmetric situation where such rules of engagement may prevent our ultimate objective from being accomplished, and those rules of engagement will bend or break. Rules may become more conditional, requiring non-lethal force up to a point, and at that point one finds out the full lethal potential of a military superpower. The President of the United States still holds the launch codes to 4,018 nuclear weapons (2017 number from treaties we have signed). For the most part, we operate under the rule that these weapons are not used. It is a level of lethality that our rules of engagement simply do not permit. However, the fact that said launch codes still remain valid points to where the military can go in the name of accomplishing an objective. So the real question to ask is what will your non-lethal military do if non-lethal force is insufficient. Do they actually hold themselves to non-lethality, even when faced with the risk of complete eradication of their society? Or is it more of a preference, with the lethality built up behind them. Most people's understanding of the military is much more of the latter. I don't know of any service men who are in the military for the purposes of killing people (though they may exist). The service men and women I talk to all recognize the need to be prepared for the moment when a need to achieve an objective in the name of right outweighs our normal rules of civility. They, of course, have varying definitions of what "right" is, but their opinions tend to follow that common structure. We see this also in warrior monks. These warriors are some of the most peaceful people you will ever meet, but they train for combat incessantly. How one trains for combat in a peaceful realm is indeed one of the great challenges the monks seek to solve. For a fictional example, consider the Octospiders from Rendezvous with Rama by Arthur C. Clarke. The Octospiders are a completely peaceful species, but 100% of their species is their military. They will seek non-lethal solutions to absolutely everything. They do this because they understand the consequences of failing to find such a solution. Those consequences are built into their genetic code. Faced with a threat so indomitable that no peaceful solution can be found, the Regent Queen of the Octospiders can call for a vote to go to war. Calling for such a vote signs her death warrant. If the Senate votes not to go to war, she is put to death. Such violent desires cannot be permitted in a Regent Queen once detected. If the Senate votes to go to war, the many (or even most) individuals undergoe a genetic level transformation. They become warriors. These warriors do not stop at anything. Their ultimate goal is never anything short of xenocide of the entire species which is threatening them. At the end of this quest, the queen and all of the warriors are put to death. Once again, this level of violence cannot be permitted in the Octospider world. The Octospiders are not truly committed to non-lethality, but they are an excellent example of how a species may operate up to a point, at which point a switch is flipped, the rules shift, and something happens. [Answer] A nonlethal military defending against a normal military is in the same position as a modern nation defending against stateless terrorists, in one sense: that "we" have to get it right *every time* and "they" have to beat us *only once* to do harm. The normal/lethal military can try, try again, because there are no permanent consequences to a failed attack. So your nonlethal military has to have an incredible technology and training advantage (think 8-foot-tall bulletproof fighting robots) in order to just hold its own. And even then, the enemy could win a war of attrition by using surprise attacks, booby traps, and the like. Every non-lethal supersoldier they kill is one you can't bring back. What's more, when you're talking about an incredibly powerful, high tech, superpolice force with fighting robots or stormtroopers marching around and gassing or tasering people... that's exactly the sort of force that people are likely to rebel against. On the offensive, it's even worse. To capture territory, you'd have to knock the enemy out with gas or something and then *physically move his unconscious soldiers* back to the new front line you want to establish, before they wake up. That would be incredibly hard labor and risky. [Answer] The military would only have a limited **deterrence value**. The empire demands something from another country. The right to establish a coaling station, the right to sell opium, or an apology for the mis-treatment of a citizen of the empire. The other government considers their options. They can give in, or they can fight and *then* give in if the fight goes against them, or they can fight to the bitter end. Their choice will be influenced by the balance of power and also by domestic politics -- if the leader gives in to foreign demands, how long will he or she stay a leader? If the empire employs non-lethal weapons, then an initial round of fighting to establish an favorable negotiating position sounds like a good idea. Soon the empire will be swamped in countless little wars. [Answer] An old saying goes: > > One can fix anything but death > > > If we apply it to this case, we realize the following. For sleeping gas an antidote or an appropriate mask can be developed, for nets a proper way to cut them can be invented, shields can be broken by an appropriate amount of energy. For a skull (and the brain within) smashed by a bullet nothing can be done. A wounded enemy can still fight back, or, even worse, if convinced of his death can even become more aggressive. So, no, a non lethal force is not sufficient against a motivated enough enemy. A dead enemy is way more safe to deal with. [Answer] No, a non-lethal army would not be effective in protecting the country. Once countries that field lethal armies figure out that all they have to face is guys with sleeping gas and nets, they'll tear the non-lethal country apart. A million men with rifles, maxim guns and artillery would utterly crush an army with sleep gas (if the wind is blowing in the right direction), shields (which are not bulletproof with late Victorian tech) and nets (issue soldiers a bayonet). Lethal army troops could slaughter the non-lethal soldiers with maxim guns or with 1865 gatling guns. Lethal soldiers could mob armored vehicles with molotov cocktails and similar weapons. Even an army of Mongolian horse archers could slaughter the non-lethal army. What do the lethal soldiers have to fear? Even if the non-lethal country is the most advanced country, look how the Zulus fought the British despite massive losses. Against a non-lethal army, a lethal army has nothing to lose. [Answer] Technically: Yes, absolutely. It actually hurts the enemy more if you leave their soldiers alive but crippled. So use biological weapons like illnesses (catapult infected corpses into enemy camps or cities, set animals free closeby that carry diseases, etc.), poisoned weapons (dip your cutting implements in a rotting corpse or feces before using them), chemical weapons that cause blindness, sound bombs that cause deafness, splinter bombs and mines, expanding low penetration bullets, etc. Now if what you wanted was a way to keep the moral high ground, then I think that's possible too. But all the other answers already go in that direction. [Answer] ## It Depends on the Mission Canada and China come to mind as countries that, while they both have very lethal militaries, mostly send them on missions where killing is not part of the plan. Canada doesn’t defend its land border, and would be worse off if it tried. It sends its forces mostly on peacekeeping missions where winning means winning hearts and minds. China does use its armed forces to deter and even threaten its neighbors (although, in a farce, even this could be an elaborate ruse), and I don't want to gloss over how it treats its own people, but as for actual military operations, it sends its troops on a lot of rescue missions and to respond to disasters. El Salvador is the modern example of e country with no military at all (largely owing to the historical role of the armies in the region in domestic politics) and the colony of Pennsylvania was a historical example of a polity that was pacifistic for religious reasons, and therefore needed to maintain good relations with its Natives rather than try to intimidate or eliminate them. (The British Army, however, was also around to back them up.) So, there is some historical basis for a country that plans to only use its military for the equivalent of law-enforcement and emergency-response missions. Maybe it gets along well enough with its neighbors and is so much smaller that trying to fight them would be counterproductive. They're better off being ostentatiously kind and harmless. [Answer] Would non-lethal mean non-wounging? A number of modern landmines (like 72b frog mines or bouncing mines) are designed to wound or cripple, more than to kill. A wounded soldier needs to be protected, transported to safety, and healed. It mobilizes resources, other soliders, and is often more profitable than just killing them. If you kill a soldier, others will keep fighting, if you cripple him, 2 or 3 will have to stop fighting. However I'm not sure if this technique can be used for all of warfare instead of just as a "side bonus". [Answer] Would a non-lethal military be effective at protecting a country [from lethal a lethal military]? Barring technology that makes them entirely impervious to death, the morale of that military is going to dive considerably the moment they start taking losses and have nothing to effectively counteract. Worse yet is that the forces would have a hard time protecting themselves, protecting the country becomes even more difficult. Making non-lethal tactics available as part of a larger arsenal is not bad, and there is a growing desire to shift that way with technologies being developed in the Less Than Lethal field to *assist* military forces in quelling populations that may largely be civilian. Also know, that military forces adapt to the tactics of their enemies, and develop technologies to counteract strategies they encounter. Sleeping gas might be effective a few times but then the next wave comes with gas masks, shields may be effective initially but then they develop larger, more powerful weapons, and so on. So, I would posit that an entirely non-lethal military *might* be at least initially effective, as a long term solution it will be very difficult to maintain. Again, barring some sort of technology making them entirely immune to taking casualties. [Answer] A chapter out of Roman history would indicate it is more effective to utilize psychological warfare, for example if you were to march into an enemy zone with ten thousand soldiers. You would then also have to account for the upkeep, whereas it would be easier to masquerade an army size of ten thousand when really you have less then half that. Giving enough reason for scare tactics and utilizing the control zone to your advantage could prove just as threatening as any real show of force. [Answer] Judging from the history of this planet, there are two avenues to peace: 1. Peace through communication; 2. Peace through superior fire power. Communication does not appear to be winning the hearts and minds of a strong set of Humans but it is by far, the superior mechanism to win a conflict. If you were cast away to a primitive planet, filled with stone age people, and you only had one handgun with 9 rounds of ammunition would you be able to take over and create an empire on this planet? After you ran out of bullets you would be left with your superior knowledge. You may obtain a foothold on establishing your new empire but you would be on an equal footing with the inhabitants after the bullets ran out. What gives you your advantage is not the ability to kill everyone but the ability to kill a single person. All you have to do is get control over a few individuals and you can exponentially build your power base to control the whole planet. Having control over those warriors who would willingly offer their lives offers you superiority over any military force. The mind is always the best weapon. Superior communications coupled with loyal followers can win against a physical military force. In the end it is a people's fear of death/pain that determines who will win any mortal conflict. If you control the mind you control the body. [Answer] Many good answers already. Let's get a real world example: In the [Annexation of Crimea by the Russian Federation](https://en.wikipedia.org/wiki/Annexation_of_Crimea_by_the_Russian_Federation), [little green men](https://en.wikipedia.org/wiki/Annexation_of_Crimea_by_the_Russian_Federation) took control of Crimea. This annexation was almost entirely bloodless. According to Wikipedia, only 2 Ukrainian navy personnel died (and 15,000 defected). Looking at the [context](https://www.reuters.com/article/us-ukraine-crisis-military-idUSBREA360GB20140407), this death looks more like homicide than military combat: > > The defence ministry spokesman said the soldier had been preparing his belongings to leave for the Ukrainian region of Mykolaev on Wednesday when an argument broke out with Russian servicemen. > > > It certainly didn't appear as necessary, due to a combination of (in order of importance): * Support among the local population * Element of surprise (*what the heck is going on?*) * The (implicit) threat of violence: although they didn't shoot much, they certainly were armed Apparently, the nature and conditions of the Russian operation were such that the Russia was able to take control of Crimea almost entirely without spilling blood. [Answer] Depending on your world's culture and politics, it could **range from totally useless to absurdly effective**. As a general rule, *human beings do not like killing other human beings*. This is as far as we know, a universal instinct found in all human beings except maybe in people with certain psychological disorders. Obviously, this instinct can be overcome. But how? There's a few ways it's been done: 1. You could **dehumanize your opponents**. You can't feel bad about killing another human being if you don't think of them as human beings anymore, they're now just *untermensch*. Obviously, this was and is the primary tactic of most ethno-nationalist and racist ideologies. 2. The above is typically paired with **self-elevation**. If your nation or ethnic group comes to think of itself as superior to all other races, a race of *übermensch*, then the killing of others becomes acceptable. 3. Alternatively, you could **exploit ideological or cultural fervor**. Convince a group of a 'greater cause' worth killing others for. This is the primary tactic of religious militarism and ideological crusades. (Heretics, bourgeoisie pigs, communist scum...) This is virtually always paired with a cultural elevation of war and militarism itself. 4. A variant of the above is to **exploit personal, national, or ethnic self-preservation**. People will take up arms if their way of life -- or life, period -- is on the line. This is generally accepted as justified but can frequently bleed into the above (the Cold War was frequently justified by this tactic by the United States and Soviet Union). 5. Another variant is to simply appeal to **revenge**. Maybe they've conquered your homeland, maybe they've bombed your family, maybe they burned down your farm, maybe you think that you wouldn't be poor if it wasn't for them. This can be a powerful appeal to take up arms, and is the primary technique of many extremist ideologies. 6. But maybe you don't need to justify it, but instead **distance yourself from the idea**. In this case, soldiers and warriors could be relegated into their own disdained class, possibly even considered an under-caste. In this way, the ruling class can take advantage of war, while simultaneously disassociating themselves from the concept. This requires a strong social or ideological hierarchy to pull off, otherwise you couldn't force people to war for you. 7. Finally, you could **appeal to necessity**. Simply avoid killing people as much as possible, but justify what suffering occurs as 'unavoidable' or 'the reality of war'. This is the primary tactic favored by modern democracies and is reflected in the way their militaries fight. (But conversely, and rightly so, a large portion of people are skeptical as to how unavoidable or necessary it really is.) All this is to say -- which ones of the above are predominant in your world? The answer to that question is the answer to how effective a non-lethal military would be. If the systems at the top of the list are the primary ones of your world? Then it would be **almost totally ineffective**. Nationalist and racist ideologies necessarily depend on the glorification of war and death, so pacifist tactics would simply be looked down upon. What if your nation adopts pacifist warfare, but it's still oppressive or colonial in some way or the other? Then the reformist and counter-movements would necessarily tend towards more militaristic beliefs. The bigger of a deal your empire makes of its pacifism and the more brutal or oppressive it is, the more likely this is. Finally, if your world is (attempting to be) primarily democratic or egalitarian? If your nation is genuinely democratic and pacifistic? Does your pacifist technique or technology *actually work*? Then it would be **stupidly effective**. Modern dictatorships and ideologies attempt to portray themselves as democratic ("People's Republic", sham elections, populism...), and to portray the opposition as being 'worse' or 'just as bad'. Being able to fight wars without killing would be an ideological coup. Modern anti-democratic ideologies appeal to the senses of self-preservation and revenge to recruit new members, while racist and militaristic ideologies attempt to portray themselves as equal to the others. They would continue on through inertia, but they would be greatly stymied. Dictatorships would be in greater trouble, as they rely on the threat of death to eliminate opposition leaders and to prevent people from joining them. This would be far more difficult in this world. A dictatorship would either have to rely on imprisonments and assassinations to keep people in line -- something which is hard to keep secret, even at the best of times. Or they would have to fully pivot and embrace militarism and murder, abandoning any pretense to being a democratic nation. A dictatorship could deal with it by appealing to nationalism or ideology -- but ideologies don't last forever. And obviously, the other democracies (and semi-democracies) of your world would have to join you to maintain their own consistency. (Though maybe a particularly militaristic democracy would avoid it, if such a thing could exist.) The end result would be **a world where death is no longer an acceptable part of war**. War, if you could even still call it that, would presumably involve capturing the opponent and engaging in prisoner exchange. Combat would simply become an extension of diplomacy. As the 'first mover', your nation would gain a tremendous advantage, though it would eventually be equalized once the others catch up. And if your nation was the inventor of the concept, it could continue to claim credit for it, perhaps indefinitely. Obviously, this is just scratching the surface. How things play out and how things end up depends greatly on the cultures in your world and something else totally different could happen. There's a lot of possibilities, and you'll simply have to think it through. [Answer] How about a highly efficient network of super spies that are able to infiltrate, capture and bring to trial any 'war criminal' who should attempt to start a war. Effectively decaptitating any possible enemy prevents attack. Note this mechanism could complement other suggested approaches. [Answer] If your army is big and technologically advanced to be able to most attacks from technologically more inferior enemy (or quickly recapture any that get through, with optional retaliation - like capturing all adult males, or all children), and you don't care about conquering other countries (just defending yours against them), then **yes, it will be effective**. As other metioned, the *big issue* is what to do with prisoners: * **Returning them** to their homes is bad, as they will attack again tomorrow knowing nothing bad can happen to them. * Putting them in **prison camps** will act as an effective deterrent, but will eventually wear down your own population which will have to guard them (or risk rebellion) * you can never trust that they will remain loyal if you try to **integrate them**. There are however quite a few non-lethal deterrent options, which will reduce any further attempts to attack you. For example: * If you technological level is way higher than anybody else and you can keep it that way (like, you're controlling all ore-rich areas), you can transport most POW to that far away continent (or similar hard-to-reach area) where they can survive (but not escape from), and which no other nation can reach (as their wooden ships with sails are way too fragile for that violent high seas which only your metal battleships can pass), while letting a few POW back home to spread a story. So families will certainly lose their breadwinners for life if they go to attack you, and will know that. Hence, they're more likely to revolt against their own government if forced to do so, rather then to attack you. * alternatively (and more dystopian), you can terrorize or brainwash them and then return all of them to their homes, where they will spread your propaganda (or even revolt against their own countrymen) until their own government has to put them in prison or kill them. Or they can be so psychologically broken so their government will have to spend year and a lots of resources on their rehabilitation before they can become productive members of society again. * Additionally, you can use drugs (which only you have advanced knowledge and machinery to produce) and make some small number of them addicts, let them experience the withdrawals, and promise them regular doses as long they keep providing you with useful information about their government, and then release them to their homes mixed with their own undamaged soldiers. * you could also make it known (and followup on that) that for any attack, you will raid their cities with overwhelming advantage, steal all their infants (all those young enough not to remember), and raise them to be your armyman. And/or use they as live shield against their attacking armies until they grow old enough, so they'll firstly have to kill their own children each time they attack you. If they do not attack, their children will grow and live good and prosper, but will now know of their parents as they will become your own people. Or even, you can advertise such kidnappings as humanitarian action for bringing prosperty and good life for poor starving children who lost their breadbringers because of misguided violent attacks of their fathers, and you are teaching them how to overcome such barbarianism of spilling blood in event of war. [Answer] Attacking a country infrastructure e.g. communications and services, or their banking system, (which is basically what happened in 9/11) if you have superior, or more ruthless forces, it's obviously easier. I believe one of the Nazis tactics during WW2 was to kidnap children from the countries they invaded, those with arian traits, basically. Russia has traditionally used scorched earth tactics and it has worked for them because Russia is huge, it worked against Napoleon's and Hitler's armies, obviously the weather helped as well. In the modern world not only does USA have a huge army but they are technologically advanced,to such an extent that they are almost untouchable. [Answer] Yes, a non lethal army can be effective, but it requires the enemy to diligently attempt to save their own people. If you have a 100% lethal laser gun that vaporizes the target, the enemy no longer needs medical supplies, medics, stretchers, grave diggers, etc. If you spray the opponent with little bits of metal that will cause bleeding out in the next 10 minutes, they need two guys to carry off the wounded (two unarmed targets to shoot at), supplies (some of which need electricity), a medic tent, doctors, chaplains, shovels, etc. You can make things much harder for your opponent by not killing them, not to mention the impact on morale when you are spared by your opponents repeatedly. ]

[Question] [ Inspired by a comical misreading of the title to [this question](https://workplace.stackexchange.com/questions/185756/how-do-i-politely-coexist-with-an-help-vampire), how would you politely coexist with a vampire? Vampires want blood. You have blood. You'd prefer to keep your blood in your veins and not be converted to a vampire through an unwanted neck bite. You have access to wooden stakes, mirrors for reflecting sunlight, and garlic, but well those aren't exactly polite to the vampire because they either cause harm in the case of the wooden stake and mirror, or at least extreme offense in the case of the garlic (think strong perfume to someone who is highly sensitive to scents). So how can you politely coexist with a vampire without becoming one yourself? Update: in response to questions in the comments, assume that you are a member of the workforce working in an office, that vampires consume any “standard” amount daily (anything commonly used in stories and movies), and that this is the only vampire that you are in contact with. [Answer] **Just a little garlic?** There must be some level of garlic which is not sufficient to render your entire office obnoxious to a vampire, but which is sufficient to remind them if they come too close, that your blood will taste unpleasant and may actually make them ill. Depending on physiology, it's possible that the "odorless garlic capsules" on sale in health food shops might provide a solution. Is the substance which makes garlic toxic to vampires the same one that makes it smelly to them (and us)? If not, you may be able to make your blood thoroughly toxic without making your presence unbearable to the vampire. Just make sure the vampire *knows* you are taking odorless garlic capsules! [Answer] # A HUG in your life: a guide to workplace harmony Your team is about to welcome a new colleague from the HUG (Haematophagous, Undead and Ghoulish) community. You may be apprehensive about this change and may harbour preconceptions about the HUG community that could cause friction with your new coworker. HR has produced this guide to reassure you that a HUG colleague can be a wonderful professional addition to your work environment and simple civility rules can ensure that your relationship is fulfilling, courteous and enriching for all. ### Terminology Many members of the HUG community use the word "vampire" to self-describe. However, some prefer other descriptors, and some are not comfortable with people who are not from a HUG background using this word. Please make sure you use the terminology your colleague prefers! We are all individuals, and we are all special. Slurs against the HUG community will not be tolerated and repeat offenses will result in disciplinary action. ### Environment People from a HUG background are sensitive to certain environmental stressors. Please minimise the use of **garlic** in your food, especially raw. In some cases, we may have to ask you to refrain from eating garlic-heavy food in the evening before a workday. If your consumption of garlic is such that it can be smelled on your sweat the next day, we can assure you that your non-HUG colleagues will be grateful as well. Direct **sunlight** can be extremely harmful to your HUG colleagues. Please ensure that rooms designated as "UV-safe" are kept protected from sunlight. Note that all windows have now been fitted with locks to prevent accidental opening; incinerating your colleagues *will* result in disciplinary action, even if done "as a prank". In case of **fire**, designated "HUG support" staff will be tasked to wrap their assigned HUG colleague in the Cofyn(TM) Safety Blanket for safe relocation to the concentration point. Please, all designated staff, ensure that you attend mandatory training and take part in one yearly exercise at the minimum. We strive for no more than 2 incinerated staff per exercise - help us reach our goal! ### Courtesy and language Many HUG colleagues will be uncomfortable with religious symbols, such as crucifixes. It's important to understand that *this is not a rejection of your faith and beliefs*, and your colleague is just experiencing a physical reaction that only superficially resembles demonic possession. We strongly encourage you to minimise the use and visibility of these symbols in the presence of your HUG colleagues: repeat offenses will result in disciplinary action. We are also fully committed to supporting your right to express your beliefs freely and without fear of repercussion. It is considered bad manners to use words such as *blood* or *bloody*, as they can cause your HUG colleagues to become hungry and distracted. Why not say *blooming* instead? Other words you may wish to avoid include "mirror", "bat" and "stakeholder". ### Feeding We expect *all our HUG staff* to **refrain from feeding on their colleagues** wherever possible. You may personally agree to provide blood for your HUG colleague, however please use the designated smoker shelters outside for this and make use of the ethanol wipes provided to clean the area. Please report any instances of unconsented feeding to your line manager, as this will allow us to enact the Stop Taking Anyone's Blood procedure to help the HUG colleague responsible better manage their needs. ### Some testimonials > > I was scared when I heard I would be working with a vampire, but Shelly's been the loveliest and a great addition to our pub quiz team! > > > > > The most important thing for me was that all my colleagues were very open and kind when I told them that I could smell their garlic bread or that it's rude to use the b-word. It's made me feel really welcome and everyone enjoyed the garlic-free breadrolls that I baked! > > > > > Being undead can be really tough, I am grateful to all my colleagues who agree to let me have a little sip when I feel my productivity is going down. > > > [Answer] # How to give blood You can turn the question a bit to see it more clearly. *How do I give blood without being bit*. This already shows that a bite isn't required. You just need to bleed. Our bleeding is controlled when going to hospital or specialised places for drawing blood. Problem solved! You just get professional bleeding equipment, draw blood and have the vampire drink it. The only problem is in the amount. If it's tiny bits it isn't a problem. However, larger amounts can leas to problems. Donating blood is often 500ml. Probably a lot more than the vampire takes, but lets take it as an example. Men are only allowed to give blood every 56 days in my country. Females every 122 days. This is a *minimum* wait time. In total men are only allowed to give 5 times, women 3 times a year. Why is this? Your blood comes back quick enough to draw 500ml much sooner. The problem lies in the further contents of the blood. There's several things coming back much slower. The worst offender is iron. This is why you aren't allowed to go earlier, nor proceed at a donation if your iron is too low. Depending on the amount of blood per feeding and the time between feeding it can be done alone. If it is more you need to employ more people to respectfully coexist with a vampire without getting bitten. Do note that if the vampire transforms you, it removes one potential returning blood supply. It is in it's best interest to aid and setup a blood bank. Even if blood banks give part of it to the vampire they often make insane amounts of profit. It is actually horrible how people come to offer blood for free to help people, which is then used for profit to help people. [Answer] **The vampire has the Black Ribbon.** That's a reference to the late Sir Terry Pratchett's work: some of his vampires wore a black ribbon to show they'd sworn off human blood. The protagonist in *Interview with the Vampire* made a similar choice, at least for a while. Essentially, you can co-exist because you can trust the vampire not to drink your blood. After all, politeness works both ways. Just as with a potentially violent human, your trust might or might not be backed by the threat of force. Maybe everyone in the office has a stake in their desk drawer and Ven Helsing on speed dial, or maybe your vampire remembers life before being turned and has no desire to harm any "fellow" humans. Either way, the polite thing is not to mention the vampirism or any stakes unless things seem to be getting out of hand - at which point the manager should have a quiet word. Some vampires can satisfy their urges with a regular visit to the abattoir, and only need human blood for the more advanced powers like turning into a bat. Such a vampire might agree to drink it only in emergencies. ("We think the victim's being held on the top floor, but the stairs are wired!" "I'll see what I can do, Commissioner. Would you mind rolling up your sleeve?") [Answer] TV tropes has a section "Our Vampires are Different" that mentions some of the various ways that various well known fictional vampires differ from other fictional vampires and from folklore vampires which also differ widely from each other. <https://tvtropes.org/pmwiki/pmwiki.php/Main/OurVampiresAreDifferent> Wikipedia used to have a chart listing lots of vampire stories and the traits that the vampires in those stories had or didn't have, but I can't find it now. Anyway, you can make up a lot of traits that your vampire does or doesn't have. If a mortal and a vampire learning to live together in peace in the main subject of your story, you should set up the story so that it is impossible for them to live in peace - or it seems impossible to the readers and the characters for them to live together in peace, until one of them realizes how it would really be easy to do so under certain conditions, and wonder why they didn't think of it earlier. Or you can make your story one where the vampire's traits make it obviusly easy for the mortal and the vampire to live together in peace, and the story can be about how the mortal and the vampire help each other with various problems they face. And if you are writing a series of stories about the mortal and the vampire, you might want to set up the traits of the vampire somewhat in between, to have a medium level of difficulting in living together in peace. That way the first story may be full of suspense whether the mortal will kill the vampire or the vampire kill the mortal, but when they find a way to live together the readers will think "That's so obvious, why didn't I think of it?". Then the following stories can have various annoyances between the mortal and the vampire, but mostly focus on their adventures together as comrades. [Answer] It's more or less a symbiotic relationship: the vampire will not have any interest in drinking your blood as long as they can get something better in exchange. What can be better than a single blood meal? More blood meals! This means that you will probably need to turn into a bait to lure other, unknowing humans, into becoming the vampire's dinner. [Answer] Does the conversion always happen? Because if one bite makes a person a vampire, then before long every single person on Earth will become a vampire. Or is the probability of turning into vampire miniscule? There are a lot of vampire stories--mostly love comedies--that detailed how to live with a vampire (sometimes the main character is the vampire and he/she needs to live with someone). The chance of turning into a vampire is miniscule and if the first bite doesn't turn someone into a vampire, it means they will never be turned. This allows the "roommate"--read "romance interest"--to supply blood for the main character everyday and so the love comedy ensues. [Answer] Some people have failed to note the obvious, or have not considered the practical implications. Vampires **hate** daylight so would be working at night, and sleeping during the day. You could therefore safely work in and leave the office during daylight hours, and the vampires would work during the night. If you needed any handovers or all-hands meetings, either the humans or vampires would dial into a Teams/Zoom/other services are available call. We just need to find an answer for the day walkers... [Answer] ## Let it pay for the rent, avoid falling in love *Politely coexist*, you gave the answer yourself. What's the issue ? Vampires are very civilized and reasonable people. They'll only "convert" you when they are in love with you. As most of us know, sex can destroy a good friendship anyway. Just avoid the L-thing and you'll be safe. [Answer] We have a example from Alucard (vampire) and Integra Hellsing (human). The Hellsing institute gives him blood and Alucard respects and recognize Integra as his master after after being woken up by her blood. [Answer] ## He's Just Another Predator A vampire, ultimately, isn't much different than any other sort of predator, except that he can (has to?) prey on humans. A couple of possibilities: * **Attacking you is dangerous**, either because you can fight back (unlikely) or because your absence at work would be noticed immediately. Your vampire coworker probably isn't looking to get arrested or hunted, so not eating where he works is just good policy. * **He's not hungry**. Most predators don't eat every single time an opportunity arises; if this vampire is trying hard to co-exist, he'll make sure he doesn't actually need any blood when he's out in public and he won't even be tempted to bite. * **Don't flatter yourself / eat the rich**. Sorry, but he's only interested in the blood of aristocrats. That's not you, sorry. Maybe if you classed it up a little. [Answer] I believe that in lieu of blood, sex will do. The problem is, you see, that the vamp cannot ask. He's too dead inside, and what remains is his polite mores mixed with extreme survival instincts. ]

[Question] [ Imagine a "soft" kind of apocalypse - nothing like Earth being hit by an asteroid. In particular - 90% of human population have just disappeared (no matter why). So there are abandoned cities and lots of vehicles, which can be used by survivors. But the question is - **for how long?** In some TV shows, even after a few (say, five, ten...) years after the apocalypse, survivors can just pick a random car and use it for transportation. It seems a bit strange to me: I guess tires, batteries or even gas will become unusable. [Answer] **Tractors, moonshine, rolling starts** **Tractors.** A tractor would be a good post-apocalyptic vehicle. You should not be madmaxing down the road at 100 mph after the apocalpyse, because stuff might be in the road. Tractors can go over or around stuff, or across fields. It seems to me like tractors keep their tires a long time. Google turned up this: of course not authoritative but worth something re tractor tires: from <http://www.tractorbynet.com/forums/kioti-owning-operating/225700-tractor-tire-longevity.html> > > Like anything else, it depends on many things. How much you use the > tractor, what kind of enviorment (flint rocks, sandy soil, lots of > road usage) all add up. but I have seen a lot of old tractors with 30 > or year older tires, cracking and splitting and chunks coming off from > spinning the tires are a bigger problem than just normal wear. But in > general they last a good long time. > > > from <http://kenjonestiresblog.com/blog/how-to-tell-if-it-is-time-for-new-tractor-farm-tires/> > > For automobiles and other vehicles that travel at fast speeds, a tire > failure can be a very dangerous situation.With off road vehicles, such > as tractors and construction equipment, while a tire failure can be > dangerous- and definitely a big headache- worn times can lead to > costly increased fuel consumption and of course the risk of costly > downtime. > > > The main thing with tires is oxidation. If you find a supply and keep them out of the air they will last longer. **Ethanol** Thinking about gasoline and diesel. Petroleum fuel has a limited shelf life. Ethanol does not - a bottle of everclear will be fine 100 years from now, and plus you can make your own moonshine. I was very impressed that in Mythbusters a normal 2010 car ran fine on moonshine. <http://mythresults.com/moonshiner-myths> > > For the performance testing, the team tested three different strengths > of moonshine: 151 proof, 170 proof, and 192 proof in a 0 to 60 mph (97 > km/h) acceleration test. The car would not start on 151 proof, it > averaged 19.4 seconds on 170 proof, and averaged 9.0 seconds on 192 > proof (96% ethanol). Next, at Petaluma Speedway, Tory drove 3 laps > running gasoline and 3 laps running 192 proof moonshine. The lap times > in the moonshine-powered car were marginally better. Tory noted that > even though the acceleration was slower on moonshine, the effect gave > him better control on the dirt surface of the track. > > > For the longevity test, they went to Thunderhill Raceway Park. Grant, > in a moonshine-fueled car, attempted to outrun Kari and Tori in an > identical but gasoline-fueled car. Grant was able to stay ahead of > them after 3 laps totaling almost 10 miles (16 km). The team declared > the myth confirmed, but Kari commented that standard car engines are > not designed to run on ethanol and that it gives poor gas mileage. > > > **Rolling start for dead battery** Re battery - how important is a battery anyway? For an automatic transmission you need one to start the car. The battery powers a starter motor whose only job is to get the engine turning fast enough that it can go by itself. But if there is a clutch pedal & your battery is dead you can start the car by rolling it up to speed and then popping the clutch. There is no reason you could not do that over and over. When you are underway if your alternator is good you should be able to run the headlights and listen to your CB. I am not certain you can do a rolling start with a tractor but I do not know why not - if it is a manual transmission the principle should be the same. My recs, Omega Man: * 1: Tractor if you can find one. * 2: Late model stick shift if no tractor * 3: Stash some spare tires in airtight environment. * 4: Stock up on Everclear (good idea anyway). Or [Bacardi 151 and mothballs](http://www.halfbakery.com/idea/Bacardi_20mothball_20emergency_20fuel_20kit_2e) * 5: Park on hills so you can easily start when your battery dies. [Answer] ## Fuel expires, tyres rot, most importantly: batteries go flat. Most of my cars of recent years have been inaccessible with a flat battery, even trying the key in the lock gets you nowhere because that apparently just sends a signal to the servo to open the lock. (Information from direct experience) * Fuel, a few months * Coolant can last a decade or more * Tyres last 5-7 years if they keep pressure or shape but if flat they'll degrade fairly quickly on the creases * Engine oil should be fine for years * Brake/Clutch/Power steering fluids should be fine assuming no leaks and it's actually brake fluid not water which degrades the seals * Screen wash not worth checking, the nozzles will have been clogged by dust * The battery will last depending on condition and load, anything from a few weeks to a few months. Once it's been flat it's effectively useless, so there's no point shopping around the town for a good battery after that first year, they'll all be dead. I'm assuming you don't much care about condition of bodywork or emissions standards. Cars in dry places will last longer, cars near the coast affected by saltwater will probably be gone by the time you find them. ## Target vehicle: Any 1980s diesel. Why? These things blow smoke like a Russian aircraft carrier but once running they ignite on compression so it doesn't matter if there are no electrics at all. Also they're rough old engines and will run on used chip fat if you sieve out the crunchy bits. Some of the old mercs were famous for running on [vegetable oil](http://www.vegetableoildiesel.co.uk/introduction.html) the only downside was the car smelling like a chippy. Also security: Most of the cars of this period had keys you could buy off the shelf, entire model ranges (Vauxhall Cavalier) were famous for effectively using the same key. Here's a [video of Jeremy Clarkson showing how to start a car of the period without even bothering with the key](https://www.youtube.com/watch?v=VNdygguAMQA) [Answer] ## Older is better Modern cars are far more complex than older engines. 1970s and 1980s era cars were designed with lots of extra space, fewer parts, and were easier to work on. I can remember my father performing maintenance on cars in the 1980s, using parts off even older cars left out in junk yards for years with no maintenance. It took skills, patience, and time. But it was possible. Modern cars, even "trivial repairs" like replacing an alternator or a belt can require specialized tools and multiple people. I had a 1990s car with an alternator that went out. To replace the alternator, the mechanic had to remove the bolts that hold the engine to the frame and *actually move the engine* with a larger lever ("rocker bar"). It was not a trivial repair after all. Computers inside cars will start to fail as the sensors wear out. They have more "fidly bits" that require higher tolerances to even work. Electric motors to drive cooling fans rather than belt-driven fans powered directly by the motor. Electronic fuel injection. Automatic transmissions with sensor arrays. **Fuel fails first.** Modern gasoline has ethanol (alcohol) in it. When that and other volatile chemicals evaporate, the fuel forms a kind of "[varnish](https://groups.google.com/forum/#!topic/sci.chem/frtSvpWy-yE)" that coats everything. When you buy a new lawn mower, the gas tank is often white. After 2-3 years of use, that gas tank is a redish brown. You can use treatments that help slow this process. But by the end of your first year, most gasoline in the US at least will be useless. Ethanol-mix fuels have a shelf life of about 100 days. [More here](http://www.fuel-testers.com/expiration_of_ethanol_gas.html). If you can find ethanol-free fuels, they last longer, but its hard to find. Stick to diesel. The fuel itself is still volatile and shouldn't be stored for [more than a year](http://www.bp.com/content/dam/bp-country/en_au/media/fuel-news/long-term-storage-diesel.pdf), but these engines can be converted to vegetable oil or similar replacement fuels. Those fuels will wear engines out faster, but can be created by your post-apocalypse world, whereas gasoline is probably not possible. **Plastic/electrical parts fail next.** Tires. Belts. Wires. Batteries. These will go next. Plastic/rubber compounds will dry rot. Batteries will fail. Modern cars require batteries. You can't run a car without one. Older cars can at least be coaxed to start without a solid, good, battery. **Roads eventually fail, too.** You're going to need off-road vehicles. At first, because so many cars are clogging roads that they're useless. Or get a bulldozer -- with that fuel efficiency? But later, the roads and bridges will fail. After a few seasons of freezing and thawing, potholes will take over. Grass and then trees will grow into the cracks and holes. **Have you considered horses?** Long-term, horses make more sense than cars. Sure, use cars while you can, for as much as you can. But plan on their expiration sooner than you would like. Work cars as hard as possible in the first few months. But after that, start working to phase them out. Horses can be bred for work or for speed, they can be trained, and they eat grass. Much easier to produce grass than fuel and rubber tires and spare parts and.... [Answer] ## Quite awhile. There will a Mechanic's Guild. Your world will have an economy of people good at keeping cars running. They will have many eager apprentices. Many others will scoff and prefer their horses, which are easier to refuel. The craftsmen will have ways to address the various problems. They will know which cars to preserve (figure cars made by the millions, toyotas, F150 and 1500/2500 trucks). They will know to gather and store fuel, cleanse contaminated or old fuel, or make new fuel. They will jealously guard a trove of collected tires in cool dry places. Keeping batteries topped up is easy with solar panels, but that only works until the batteries get too old. Lead-acid batteries are ancient technology, and the materials are very recyclable, so it's likely they'll find a way to make them. So the answer is "indefinitely, but only for a few people." The issue will be a lot more about who has the influence/wealth/control to be one of the ones with cars. Roads will be a bigger problem, because with so few users, no one will want to maintain them. **Your heroes will have little chance of randomly scavenging working vehicles, because the guild will have been there first**, picking anything usable. ## Don't forget the Robber Barons Almost half of America's rail miles were removed in the 20th century, mostly in the northeast. What remains is maintained in absolutely pristine condition, with technologies that didn't exist in the "golden age." It will last for many years with minimal maintenance (assuming train weight and speed fall significantly, as they would without big industry and electric signaling). Rail equipment is made of tougher stuff. So **passenger rail would be the dominant mode of inter-town transport**. There are plenty of passenger trains available when you figure the urban commuter trains. Of course, this monopoly will make them formidably powerful, especially since they have their own genuine police departments, who will step up to quell lawlessness *where it affects railroad interests*. They will collect Hummers and MRAPs from municipal police departments who "aren't using them anymore". And they will mobilize scary-fast because they will travel the long distances by rail. This will make them a force only fools will challenge. Effectively the railroads will either make the government they need, or prop up a national government as needed. They won't be *against* private vehicle usage. If anything they will help support it, because their own needs for small vehicles and engines will help sustain the mechanic's guild. On the other hand they will compete in the market for working vehicles and for mechanic's time, i.e. Good luck getting a car fixed in Omaha if it doesn't say Union Pacific on the door. [Answer] Gasoline has a shelf life of about three months. You could make your own fuel, probably some ethanol mix, but then you will have to deal with cars breaking, with good care and regular maintenance I would say you can keep your car in good, working order for about 11 years (personal experience) [Answer] This is *not* a wholly theoretical question. Cuba has not imported cars or car parts for more than 50 years, but the the island's cars have been kept running through a combination of cannibalization, improvisation, and sheer will. (Incidentally, the paucity of imports is usually blamed on a boycott of its large neighbor, the US, but this is not the case. American-made cars are not the majority of cars on *American* roads. Nothing stops Cubans from buying Toyotas, Hyundais, or Tatas except what stops me from buying Maseratis, lack of the money to do so.) Probably, the best bet would be to start with Diesel-powered vehicles. The high-compression engines are much less sensitive to fuel-types, and can be adjusted to burn almost any burnable liquids. Gasoline-powered engines are far more sensitive and have many more parts to keep working. Someone mentioned ethanol. Pure ethanol attacks the plastics and resins used to make parts of the fuel pathway, and is much lower energy, both by volume and by the labor expended refining it than petroleum-based fuels. If your survivors are in California or Texas, an early priority would be to get the oil wells and oil refineries working again. [Answer] Older (non common-rail) diesel vehicles are a good bet, diesel fuel can remain viable for a year or more if it's stored somewhere clean and dry and older engines can be persuaded to run acceptably relatively degraded diesel (unlike modern ones which are much more sensitive to fuel quality) or even on used cooking oil which will help extend your supplies. Flat batteries are a problem in terms of "jump in and go" as they will go flat in a month or so (less if the car has a persistent drain such as an alarm system) but assuming your apocalypse hasn't obscured the sun you could use a solar charger to get one going. It'll take a while though so if there is peril that would prevent you staying in one place for a couple of days you are going to struggle. Once you've got one charged however it's just a case of using it frequently enough to let the alternator do it's job. Once you've got a running motor if you can gather a few spare batteries you can use the working car's alternator to charge these up giving you the ability to jump start other vehicles, hell if you can get your hands on a solar generator (one off this list would be a start: <http://www.jpost.com/PromoContent/8-Best-Reviewed-Portable-Solar-Power-Generators-for-2016-439477>) then you could use regular mains-powered car battery chargers or even charge plug-in electric vehicles! [Answer] Older is definitely better, but there are other things you need to know about in the first few months after the disaster. Firstly, lead-acid batteries self-discharge over a few months and once discharged, they sulphate and become scrap. So as soon as possible, you need to scavenge lots and lots of batteries and put them on float charging. How? Well, a solar panel generates ~250W at ~30V on a sunny day and ~25W on a cloudy one. If one knows a little electronics, a low-current precisely regulated voltage source is not hard to lash up. Or you could recharge them every month at higher current, using a scavenged DMM (digital multimeter) to work out when they are fully recharged. Or hack the mains-driven float charger in a battery distributor to work off solar panel DC instead. Next, Tyres and other rubber components will rot in air. Much faster, if in the sun, and in the case of tyres if they go flat with the weight of a car on them. So you'd want to stockpile appropriate hoses and tyres, and store them under cover. A cave or a deep basement would be ideal (stable cool temperatures year-round). Finally, fuel. It will probably last a year (for use in a vehicle without modern fuel injection) but it won't last a lifetime. Modern fuel-injected vehicles, most especially diesels, are highly sensitive to the quality of your fuel. Degraded fuel will destroy the injection system. So to the choice of vehicle. I'd suggest two options. Firstly, light military vehicles (jeeps, land-rovers, humvees). Preferably, older. The military want their vehicles to run on whatever is available: dodgy diesel, kerosene, petrol, cooking oil, heating oil, and to heck with the clouds of smoke. If anything will run on decades-old fuel, an elderly mil-spec vehicle will. Secondly, if you can find one: a car or bus that has been converted to run on LPG (Liquid Petroleum Gas). I expect that a tank of LPG (mix of propane and butane) will stay much the same until the tank fails and it vaporises. Centuries, probably. Such cars are rarities, but they do exist. The other snag is that LPG cannot be used for compression ignition. Such a car will depend on spark ignition, and therefore on having a battery. Fork-lift trucks commonly run on LPG. Might it be feasible to hybridize a forklift truck and a petrol car using just hand tools and welding gear? Those prongs out the front might actually be useful for shifting debris off the roads. If all the lead-acid batteries are scrap by the time you get on top of things, there may be alternatives. An AA NiMH rechargeable battery is not destroyed by going flat and is typically 2Ah. Eleven in series is ~13.2V. About sixty in parallel should be able to power a starter motor (briefly needs several hundred amps under effective short-circuit conditions). So you need to connect up an array of ~660 AA cells to replace a lead-acid battery. Maybe. I've never tried! The voltage is not exactly the same as a lead-acid battery, so the vehicle couldn't be trusted to charge them correctly without some electronic tweaking. But it would start and run minus the alternator, with a solar panel lash-up for charging the battery pack. Or you might be able to find a NiFe battery. These are the ultimate rechargeable batteries for post-apocalyptic survivors. Overcharge them, undercharge them, short-circuit them, leave them to go flat and then years longer: they will survive it all. Because they weigh twice as much as Lead-Acid and because they go flat all by themselves in a mere few weeks, they are now rarities. The London Underground (railway) still uses them to power its overnight maintenance train locomotives, and if there are any pre-war lifts (elevators) still in use in their original form, they were used for regenerative start/stop operation. Summary. Batteries, petrol/diesel fuel, rubber components: these are the things that you can't rely on scavenging, because they decompose quite rapidly whether in use or not. For the rest, if you can build a fleet of identical vehicles, then every part that breaks can be replaced from one of the others, for many decades. (The ultimate longevity of electronics is probably not yet known, which is another reason why old vehicles pre-dating mission-critical automotive electronics are best). [Answer] Your main problems won't be with vehicles. Cars can run on wood-gas with unsophisticated modifications, so fuel's not the biggest problem. Batteries can be recharged and reconditioned and basic ones aren't that difficult to make. Spare parts can be sourced from the millions of abandoned vehicles all around you. A lot of those vehicles will be relatively protected from the elements, and lets not forget the thousands of junk yards we've got with spare parts already stripped and sorted for you. Your biggest problem will be the infrastructure, the roads basically. Keeping cars running should be within the capability of most small communities, that gear head who used to bore you at parties ? He's pretty damn essential now. Now hands up everyone who knows someone who can fix a road, or a bridge, how about a tunnel ? Even if you did know someone the resources they'd need would make road building and repair out of reach for all but the largest and most developed of communities. 99% of modern cars will be usable only until the potholes get too deep, a couple of winters basically. You can go for specialist vehicles, off road, amphibious even, but the less mainstream the vehicle then the harder it'll be to maintain them. Personally I'd opt for a truck that can run along railway tracks as well the road. Railways and bridges won't have as much wear and tear, they'll last longer, they won't be blocked by 1000s of abandoned vehicles, most rail tunnels will be passable. You can switch between road and rail as needed. [Answer] Batteries used to be sold *without* sulfuric acid. The customer (or service store) would add that. A battery without acid will be good forever. Chances are that after a couple of years, no car on the street will have a battery with a charge though. So, no, you're not going to walk up to a car in a parking lot 5 years after and drive away. Diesel is the way to go. As far as gasoline engines go, if the engine of a new car is kept "dry" then old gasoline can be used (possibly needing filtration first). It doesn't go "bad" in the sense that it doesn't burn, but the ignition won't be as efficient without the additives, which may have plated out (as many others have mentioned). Tires do become more and more brittle. Modern cars use the *air* in the inner tube to reduce the transmission of shocks from the road to the driver (and passengers and cargo and engine). There's no real reason you couldn't use steel wheels, if you'd be willing to tolerate the jolts. Sure you could store tires somewhere where there's no air (oxygen), and where it's cool. But that doesn't seem very practical to me. Chances are after 10 years or so, you'll have to have found a replacement for rubber tires. If you limit speeds to horse and buggy, then you might be able to fill the tires with saw-dust, rags, or pretty much anything and have them work for a while, even after decades. The real question is the electronics. My guess is that they'll be good for decades, but its a real unknown. The other problem is plants, insects, and small animals. They're going to live in any available car, in the nooks and crannies. Again, I doubt that a car on the street will be likely to start after 10 years. Cars in dealerships and in garages are much better choices. [Answer] Those mentioning focusing on older diesel engines because they can run on other fuels - it's worth noting that, in a real pinch, diesels will run on engine oil itself. As explained on [Diesel Engine Runaway](https://en.wikipedia.org/wiki/Diesel_engine_runaway), motor oil has roughly the same energy density as diesel fuel. It's likely more viscous than diesel so would give the fuel pump more work to do, but consider that large automotive stores will have shelves full of oil in airtight bottles. A supply like this could last years, probably enough to get you from one side of whatever country to the other. Okay, the emissions would be terrible, but in an apocalyptic scenario, that's pretty low priority, and with so few cars in use, the planet might even tolerate it. ]

[Question] [ Imagine the speed of light is 100 times that in our universe. Light from the moon takes about 1/100th of a second, the sunlight reaches our eyes in about 4 seconds, from nearby Alpha Centauri in about 16 days, and from the galactic center in about 260 years. Assuming the laws of relativity would be scaled up to the higher value of $c$, would that make it easier to travel to other worlds? Besides being awesome, would there be any other important considerations that I should keep in mind? *Edit: In light of the first few responses, if at all possible, I would like to assume scenarios where the universe does not burn down horribly. But perhaps such a fast propagation of causality leaves me with no outs...* [Answer] If you say you want to make the speed of light 100 times as high, you have to say what you want to keep constant. I'll assume you want to keep constant the sizes of things (because if light is 100 times as fast, but all things are 100 times as large, the apparent speed is again the same), and also keep the time scales of physical processes (again, because if light goes 100 times as fast, but you also live 100 times as fast, you've won nothing). # Summary I think by carefully adjusting the constants, you could make it so that *most* things stay more or less the same. However, there will be inevitable changes in the details, especially forget about earth magnetic field (and associated effects, like polar lights), permanent magnets, magnetic hard disks, golden gold and liquid mercury. **Edit:** As Peter Cordes mentioned in the comments, also a lot of electric technology (especially motors and generators, as well as coils for circuits) depend on magnetic fields. This would have negatively affected all electric technology, and might result in a steampunk-like world (because steam engines obviously don't rely on magnetic fields). # How would physics have to be changed? Let's first start with Maxwell's equations, which actually determine the speed of light [note: I'll use SI units throughout; some argumentations would have to be adapted for other unit systems, because they have less constants into which to incorporate the effects, but the ultimate effects would of course be the same]. In Maxwell's equations, there are two constants, $\epsilon\_0$ which effectively determines the strength of an electric field generated by a charge density $\rho$ via the source equation $$\operatorname{div} \vec E = \rho/\epsilon\_0$$ and $\mu\_0$ which effectively determines the strength of the magnetic field generated by a current density $\vec j$ via $$\operatorname{curl} \vec B=\mu\_0 \vec j$$ (note that unlike in the electric case this is not the complete Maxwell equation). Maxwell's equations (the parts which I omitted above) predict electromagnetic waves going with the speed $$c = \frac{1}{\sqrt{\epsilon\_0\mu\_0}}$$ So you see, to modify the speed of light, you have to modify either the electric or the magnetic field a charge/current generates. For example, you could reduce both electromagnetic constants by a factor 1/100; that would make electric fields 100 times as strong (remember, $\epsilon\_0$ is in the denominator of the source equation) and magnetic fields 1/100 as strong. Alternatively you could leave $\epsilon\_0$ unchanged, but apply a factor 1/10000 to $\mu\_0$, thus only (massively) weakening all magnetic fields, or vice versa, making electric fields much stronger but leaving magnetic fields unchanged. Indeed, you could even make one of them larger while reducing the other even more at the same time. So you see we have a certain freedom here, which we have to solve in another way. So let's now look at the condition that sizes should remain the same. Well, the relevant size is, of course, the size of atoms, which basically can be written in terms of the Bohr radius, $$a\_0 = \frac{4\pi\epsilon\_0\hbar^2}{m\_e e^2}$$ where $m\_e$ is the electron's mass, $e$ is its charge, and $\hbar$ is Planck's (reduced) constant. This, of course, means we've got yet another constant we can play with, so this alone won't help us. So let's look at the second condition, that time scales also should be kept constants. Now quantum mechanics tells us that time scales are given by $\hbar/E$ where $E$ is an energy scale; for atomic processes (and thus also for chemistry and thus life) the relevant energy scale is given by the Rydberg energy, $$Ry = \frac{e^2}{2(4\pi\epsilon\_0)a\_0}$$ That means, the time scale can be characterized by $$\tau = \frac{2\hbar(4\pi\epsilon\_0)a\_0}{e^2}$$ If we want to keep both $a\_0$ and $\tau$ (that is, sizes and time scales) constant, we need to keep both $\hbar$ and $\epsilon\_0$ unchanged. Remembering the discussion above, this means we have to give $\mu\_0$ a factor of $10000$. # So what would be the result? The most direct change would be that magnetic fields would be *much* weaker, by a factor of 10000. Basically, **forget about the magnetic field of earth.** Also, forget about permanent magnets; they will be too weak to be of any use. Also, magnetic storage will probably not be a feasible way to store information. Actually, given that the very existence of ferromagnetism depends on sufficiently strong magnetic interaction, I'm not sure if there would be *any* ferromagnetism; if it existed, it would be a low-temperature phenomenon. For further effects, let's look at the most important constant in electromagnetism: The fine structure constant, $\alpha = \frac{e^2}{4\pi\epsilon\_0\hbar c}$ Since the only constant which changes is $c$, this would mean that $\alpha$ is only 1/100 as large as in our world. Which is not that surprising, given that the name of that constant comes from its relevance for the atomic fine structure, which is caused by relativistic effects. With a higher speed of light, of course you expect relativistic effects to be reduced. Note that the dominant energies in atoms would *not* be changed (that's a direct consequence from neither $\hbar$ nor the relevant time scales being changed). Well, given this, we come to a very visible (and surprising) effect of a much higher speed of light: **Gold would [no longer be golden!](http://hindi-1914.blogspot.de/2007/11/relativity-in-chemistry-color-of-gold.html)** And moreover, mercury would no longer be liquid either. Note that relativistic effects are important mostly for heavy elements, so the properties of the most important elements for life (especially hydrogen, oxygen, nitrogen and carbon) should not be substantially changed; life would probably not be affected. However I'm not sure what it would do with nuclear physics which is much more dominated by relativistic effects; mass defects would certainly be much more pronounced, but it might possibly alter the whole nuclear stability properties. On the other hand, one might evade that problem by adjusting some other fundamental constants relevant for nuclear physics. Since the energy scales would be kept constant, $E=mc^2$ would mean a 10000-fold increase of the energy per mass; so a matter-antimatter annihilation would increase correspondingly. Whether nuclear processes also show this additional energy would again depend on the adjustments to nuclear physics; my bet would be that if you make them so that the stable isotopes remain the same, you'd also get approximately the same energy out of your nuclear processes. But that's just a guess; I don't know enough about nuclear physics to really say. Given that in General Relativity, energy and momentum are the source of gravitation, a higher energy would also imply stronger gravitation; however you've got yet again a constant you can modify to avoid this: Just make the gravitational constant smaller by an appropriate amount. And of course, you'd only get relativistic effects at high speeds; that's after all the whole point of it. So you'd get fast communication over wide distances, and also possibly very fast space travel (although we are still far from even reaching relativistic speeds for spaceships within our "slow-light" universe). [Answer] The speed of light is a squared constant in $e=mc^2$, so multiplying it by 100 means atomic reactions — nuclear bombs and plants, and solar fusion — will be approximately **10,000** times more powerful. I suspect that this would either: 1. Make it impossible for a star's gravity to hold it together against its fusion core unless it's super-massive. 2. Or make it so stars expand more (greater internal pressure from fusion vs the constriction force of gravity). Either of which would probably make our form of life impossible. Certainly our solar system wouldn't exists in its current form. [Answer] **Would that make it easier to travel to other worlds?** In terms of regular (rocket powered) space-flight, I don't think so. The distances between stars are so huge that the amount of fuel we need to *approach* speeds where special relativity becomes important is much, much, larger than the spaceship itself. A quick Wikipedia search on [Lorentz factor](http://en.wikipedia.org/wiki/Lorentz_factor#Numerical_values) shows that you need to get to ~87% of the speed of light before time appears to slowed by half. With the current speed of light, to get to that speed, a 100 tonne spaceship will need [9.2 million, million, GJ of energy](http://www.wolframalpha.com/input/?i=kinetic%20energy%20of%20100%20tonne%20mass%20travelling%20at%200.87c). If you were to bump up *c* by a factor of 100, you should be able to ignore Lorentz factors. Instead, you'd only need 3.4 million, million GJ. I have no idea what that is in practical terms, but I expect it's still a lot. **would there be any other important considerations that I should keep in mind?** Magnetic and/or electric fields would be influenced as well. The speed of light is can be expressed as the result of other fundamental constants in nature; [the permeability and the permittivity of space](http://en.wikipedia.org/wiki/Electromagnetic_wave_equation). Because these are all related, you'll have to change one (or both) of these too. That will effect motors, and electronics. I won't comment on *how* they will effect them. As I really can't grok the physics behind it. [Answer] Radiation would be more energetic. Visible light (~1000 nanometres) would be as dangerously ionizing as X-ray radiation is on earth (~10 nanometres). UV light would be like gamma rays. You'd need some really intense sun-block to walk outdoors. Not exactly sure how the eyes' photoreceptors work, but it could be that the visible light photons would be too energetic and would just pass right through without being captured, and you might instead be seeing in entirely different far-infrared wavelengths instead. Either that, or you'd still see in visible light, but the brightness would seem WAY higher. Seems like so many of these questions end with "you'd see a really lovely light show, and then die in a really horrible way". [Answer] I'm not physicist so I might be wrong, but I don't think the other answers are correct. In fact, I think that *if the speed of light suddenly got 100 times higher, absolutely nothing would change*. We even might not be able to realize it has changed. In our daily lives we perceive space and time as two separate things; but in reality, they are the same exact thing, called spacetime. Everything in the universe, including light and ourselves, *always* move through spacetime at c, the speed of light. Space and time are however orthogonal, and this allows us to move in either as different speeds, *as long as the total spacetime travel speed is always `c`*; never less, never more. So, if you are not moving through space or moving very slowly (like ourselves) you move through time at near the speed of light. If you travel at near the speed of light, you don't travel through time. (Light never travels through time, and thus only travels through space at maximum speed, c; this happens because it has no mass) With all that said, if c was 100 times higher, time would also be 100 times as fast for us. The chemical reactions in our brain would happen more quickly; but this means we will think "faster" so I don't think we would even realize it. Some other answers said atomic bombs and stuff like that would be much more powerful. But is it true? I don't think so; more energy is released, but in much less time as time is quicker, so it would feel exactly the same. In short, I am not a physicist and I may be wrong, but from my understanding `c` is a constant that affects everything, and thus if it increases or decreases *everything* increases or decreases with it leading to no observable changes. In fact - from my understanding - it could even be constantly changing and we would have no way to know. In fact, thinking of it a bit more, it's just not possible to say that c = c \* 100. Since c is m/s, if it travels 100 times more meters, time will be 100 times quicker; so it becomes c = 100m / 100s which has no change. [Answer] Suddenly computer networks and computers in general can be made a lot faster (or at least networks can have less latency). [Answer] Having looked it up, my understanding is now the expected result is stars would burn faster, releasing more energy. Increasing the speed of light appears (perhaps it doesn't have to be this way--hard to say) to decrease the binding energies at the same ratio so reactions drive normally; however the consequence of a higher speed of light is nuclear reactions run faster at the same energy levels, and energy from gravity wells doesn't change so fast. This yields hotter stars in smaller sizes. KSP anybody? ]

[Question] [ I'm imagining a system with a star and something like 6-8 planets. The planets' orbits are (relatively) close to each other, and all share an orbital period that is exactly the same. I.e. the length of a year would be exactly the same on all planets. I've even gone so far as to imagine a system where the planets are all in a line, with a gravity elevator linking each planet to its neighbor(s). Something like this: ``` (star) A-----B-----C-----D-----F-----G ``` I understand that they would have to be offset a bit (or in slightly different orbital planes) in order to not perpetually eclipse each other. Assume that technology exists allowing a species to exactly place a planet into the desired orbit, and even make routine corrections (though I'd prefer to not have to if possible). In other words, you can almost treat each planet as a giant spaceship as long as it would not need to use any thrust 99% of the time. In this scenario the planets would all be roughly Earth-sized and have somewhat Earth-like climates, though probably the innermost would be hotter and the outermost colder. From what I understand, a planet orbiting at x (average) distance from the star has a specific range of velocities it must adhere to--if it is too slow it would crash into the star, and if it is too fast it would escape the system altogether. I also know that the innermost planets would travel slower and the outer ones much faster in order to make one revolution in the same period. Finally, I'm guessing the distance between each planet would vary throughout their orbits since the orbits would be elliptical (so the gravity elevators would be long and flexible). But I don't understand the math enough to do the calculations. So specifically I'd like to know: 1. Is is possible for such a system to exist? 2. If so, are there are limitations/constraints on the length of a year in this system, or on the type of star, distance from the star, etc? 3. How far apart would the planets have to be in order for the gravity of each (assuming Earth-like mass) to not pull its' neighbors out of orbit? [Answer] > > Is it possible for such a system to exist? > > > I'm sorry, but no. At least not according to orbital mechanics as currently understood. [Kepler's third law of planetary motion](https://en.wikipedia.org/wiki/Kepler's_laws_of_planetary_motion#Third_law) is one of the old workhorses of orbital mechanics, and applies in this case. As translated and summarized by Wikipedia, it states that: > > The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit. > > > or, mathematically, $$ P^2 \propto a^3 $$ or, stated differently, there exists some constant $k$ such that $$ P^2 = k a^3 $$ [The semi-major axis is one of the defining parameters of an ellipse.](https://en.wikipedia.org/wiki/Semi-major_and_semi-minor_axes#Ellipse) (Put simply, the semi-major axis is the longer radius of the ellipse.) Since [orbits are ellipses](https://en.wikipedia.org/wiki/Kepler's_laws_of_planetary_motion#First_law) ([also](https://astronomy.stackexchange.com/q/22721/525 "Is a perfectly circular orbit possible? on Astronomy SE")), this applies. Consequently, the least you change the distance at which the planet orbits from the star, the orbital period will change, however little. If the orbital periods are different, then the planets will drift apart over time, however slowly. (They *will* occasionally line up, assuming that the orbits are themselves stable and [closed](https://en.wikipedia.org/wiki/Orbit#Orbital_energies_and_orbit_shapes). A variant of this occured for some of the planets in our solar system in the 1970s-1980s, giving our [solar system grand tour](https://en.wikipedia.org/wiki/Grand_Tour_program) taken by the [Voyager 1](https://en.wikipedia.org/wiki/Voyager_1) and [Voyager 2](https://en.wikipedia.org/wiki/Voyager_2) probes.) Ergo, **the system you describe cannot exist when all planets are in the same plane.** If the planets are in different planes (technically, have different inclinations relative to the solar system ecliptic, which in this case could probably conveniently be defined as the equator plane of the star), then the distance between the planets will change as they move through their orbits. You can visualize this by considering two planets, orbiting the same star with the same velocity but at different inclinations; if you trace their orbital trajectories, you will see that the distance between the two planets varies throughout their orbits. Any kind of rigid construction attaching them to one another would interfere with their movement and either cause them to crash into each other, tear the structure apart, or tear the structure from one or both of the planets involved. Either way, **having the planets in different planes is not an option either.** So, sorry, **no, you can't have what you want.** [Answer] The only way such an arrangement could exist is having external planet being the heaviest and the others each in [L1](https://en.wikipedia.org/wiki/Lagrangian_point) point of next outer one. Unfortunately such an arrangement is not stable, so it would need corrections to keep alignment and avoid planets to drift out. This kind of correction would be quite small, if you do it before planet/spaceship drifts too far from its ideal position. Any (sufficiently strong) physical link between planets (as OP seems to indicate talking about "gravity link", which I interpret as a "space elevator" thing, but I could be very wrong) would contribute to stabilize the system (a really linked system would assume the required configuration in *any* orbit due to tidal forces, but required tensile stress rapidly becomes unmanageable, even in the SF context, as soon as planets are not in the proposed configuration). It is unclear how such a linked system may work without tidal locked planets. Note: Lagrangian points are computed on a 3-body system, your multi-body system would need some adjustment, but any alien race able to move planets shouldn't have problems working out details ;) [Answer] **TL;DR: Nothing like you describe is possible with current technology (or anything likely in the near future), but several configurations are possible using technology well within the realm of science fiction.** As others have mentioned, the linear arrangement you mentioned is not possible (unless the connections between the planets are exremely strong and rigid). As others have also mentioned, a [Klemperer rosette](https://en.wikipedia.org/wiki/Klemperer_rosette) would allow the planets to maintain fixed relative distances, but the orbits would not be stable to small perturbations. The Klemperer rosette also has the possible disadvantage that the distance between the planets is similar to the distance between the planets and the central star (i.e. quite large). There is a another configuration worth considering, although it doesn't solve all of these problems: the proposed orbital configuration for the [Laser Interferometer Space Antenna (LISA)](http://www.esa.int/Our_Activities/Space_Science/LISA):  In the proposed LISA mission, three satellites orbit the sun with roughly the same orbital period as the Earth. Their orbital planes are oriented at slightly different angles and their orbital phases are synchronized so that the three sattelites orbit the sun while maintaining a fixed relative distance. As seen in the picture, the constellation of sattelites also rotates in the plane defined by the three satellites. Note that the satellites are not attached to each other in any way (the lines on the diagram indicate laser beams used to measure the stretching of space). While this keeps the planets relatively close together, I believe\* it suffers from the same instability problem as the Klemperer rosette, so while it works for satellites which are small and far away from each other, the gravitational effects between the planets in a LISA-like configuration would be considerable, and would lead to significant instability. The interplanetary gravitational forces would also cause the planets to be non-periodic, although not in a way that would neccesarily present any practical problems.\*\* So, to answer your questions: 1. It is not possible for a system like the one you describe to exist without some repeated adjustments of the orbits, or extremely strong connections between the planets. However, some configurations require more energy to maintain (or stronger connections) than others. The Klemperer rosette and the LISA configuration both require orbital adjustments only to fix any drift away from their initial configuration, so in principle this could be done with a relatively small amount of energy or relatively weak interplanetary connections.\*\*\* 2. According to [Kepler's third law](https://en.wikipedia.org/wiki/Kepler%27s_laws_of_planetary_motion#Third_law), the length of year, distance of the planet from the star, and mass of the star cannot be varied independently, although there is no restriction on any one of these parameters independently. In principle\*\*\*\* you can pick whatever you want for any two of these parameters, but your choice of the first two determines the third parameter. This is still true for the Klemperer rosette and the LISA configuration, although the exact relationship between the parameters would be different. In the Klemperer rosette, the gravitational forces between the planets would shorten the length of year for any given mass of star and radius of orbit, although the effect would be very small unless the planets were very massive, or the star very small. In the LISA configuration, the time it takes for the planets to orbit the star would be about the same as you would expect from Kepler's third law. Depending on the rotational axes of the planets themselves, the seasons could change in very complicated ways since the season depends on the orientation of the planet's rotational axis with respect to the incoming starlight. This in turn depends on the orientation of the rotational axis relative to the orbital plane of the planetary constellation, as well as how the constellation is rotated in its own plane. Since the rotation of the constellation has a different period than the orbit of the constellation around the sun\*\*, the angle between a planet's rotational axis and the incoming starlight could change in quite complicated ways over cycles of many (orbital) years. 3. The gravitational force between two objects is proportional to $1/r^2$, where $r$ is the distance between the objects. This means that planets will feel each other's gravitational forces no matter how far away they are from each other. In the case of the Klemperer rosette and the LISA configuration, these forces will affect the orbits (see the previous two paragraphs), but these effects are not catastrophic. The bigger problem is that these configurations are unstable, so the gravitational effects of everything else in the universe will be catastrophic in the long run. It is these effects that you have to counteract using orbital adjustments or strong interplanetary connections. Luckly, most of the rest of the universe is very far away, so these effects are small and, with the right sci-fi technology not terribly hard to fix. **In short, if technology capable of significantly influencing the orbits of planets is avaiable, the Klemperer rosette or the LISA configuration are both feasible.** \* While I am a physicist, orbital mechanics is not my area of expertise, and I haven't done any calculations related to this post, so take what I say with a grain of salt. \*\* The planetary constellation would rotate around its center of mass faster that it would due to the relative canting of the orbital planes. After one orbit around the central star, the constellation would be in the same place, but rotated differently than it was at the same time in the previous year. \*\*\* Of course adjusting a planet's orbit by any measureable amount is still very hard, so the amount of energy required would be enormous compared to anything feasible with our current technology. \*\*\*\* There are practical limits on the distance to the star and the mass of the start however. The planets should not be inside the star, or so far away that they are close to other stars. If the mass of the star is too small it will just be a planet or cloud of dust and gas, if it is too large it will turn into a black hole, making things complicated nearby. [Answer] This problem is easiest to solve in a co-rotating frame, where you sum together the sun's gravity and the centripetal force to produce an effective potential with a flat spot which tells you where a planet can sit. If the flat spot is a minimum, the system is stable; if it's a maximum, it's unstable, but can be stabilized with appropriate application of external restoring forces (planet-scale station-keeping thrusters of some sort!). In this case, of course, you won't just have the sun's gravity to worry about--you'll be summing up the gravities of all the different planets, which gives you a system of multiple equations to solve, but the basic idea is still the same. Fix the orbital periods to all be the same (exactly what the value is doesn't matter, we'll just make it a variable that we can solve for), work in a co-rotating frame to turn it into a one-dimensional problem, and solve for the distances that balance forces so the planets don't move inward or outward. We can also significantly simplify things by assuming that all the planets have the same mass. The centrifugal acceleration of each planet is given, in terms of orbital period, by $4\pi^2\frac{r}{T^2}$, where $T$ is the orbital period. We're fixing the orbital period as constant for all the planets, so we can gather all the constant terms together and write the centrifugal acceleration as $\alpha r$--i.e., linear in radius. The gravitatonal acceleration will be the sum of contributions from the sun and all the other planets. Since the sun has a different mass from each planet, and it's gravity will always be in the same direction for every planet, it will be convenient to separate out its contribution. So, the net radial acceleration of each planet can be written as $$a\_p = -\frac{GM\_S}{r\_p^2} + \alpha r\_p + GM\_P\sum\_i \frac{sgn(r\_i-r\_p)}{(r\_i-r\_p)^2}$$ If there are exactly 6 planets, that expands out to, e.g., $$a\_1 = -\frac{GM\_S}{r\_1^2} + \alpha r\_1 + GM\_P(\frac{sgn(r\_2-r\_1)}{(r\_2-r\_1)^2} + \frac{sgn(r\_3-r\_1)}{(r\_3-r\_1)^2} + \frac{sgn(r\_4-r\_1)}{(r\_4-r\_1)^2} + \frac{sgn(r\_5-r\_1)}{(r\_5-r\_1)^2} + \frac{sgn(r\_6-r\_1)}{(r\_6-r\_1)^2})$$ (Note that the sign of the planet's radius minus itself is zero, so the self-interaction term falls out when you expand the summation.) Now, we want the radial accelerations to all be zero. So, we can write out the complete system of equations (with signs resolved assuming they are ordered from 1 to 6 moving outwards, and terms re-ordered to make opportunities for cancellation more obvious) as follows: $$-\frac{GM\_S}{r\_1^2} + \alpha r\_1 + GM\_P[(r\_1-r\_2)^{-2} + (r\_1-r\_3)^{-2} + (r\_1-r\_4)^{-2} + (r\_1-r\_5)^{-2} + (r\_1-r\_6)^{-2}] = 0$$ $$-\frac{GM\_S}{r\_2^2} + \alpha r\_2 + GM\_P[-(r\_1-r\_2)^{-2} + (r\_2-r\_3)^{-2} + (r\_2-r\_4)^{-2} + (r\_2-r\_5)^{-2} + (r\_2-r\_6)^{-2}] = 0$$ $$-\frac{GM\_S}{r\_3^2} + \alpha r\_3 + GM\_P[-(r\_1-r\_3)^{-2} - (r\_2-r\_3)^{-2} + (r\_3-r\_4)^{-2} + (r\_3-r\_5)^{-2} + (r\_3-r\_6)^{-2}] = 0$$ $$-\frac{GM\_S}{r\_4^2} + \alpha r\_4 + GM\_P[-(r\_1-r\_4)^{-2} - (r\_2-r\_4)^{-2} - (r\_3-r\_4)^{-2} + (r\_4-r\_5)^{-2} + (r\_4-r\_6)^{-2}] = 0$$ $$-\frac{GM\_S}{r\_5^2} + \alpha r\_5 + GM\_P[-(r\_1-r\_5)^{-2} - (r\_2-r\_5)^{-2} - (r\_3-r\_5)^{-2} - (r\_4-r\_5)^{-2} + (r\_5-r\_6)^{-2}] = 0$$ $$-\frac{GM\_S}{r\_6^2} + \alpha r\_6 + GM\_P[-(r\_1-r\_6)^{-2} - (r\_2-r\_6)^{-2} - (r\_3-r\_6)^{-2} - (r\_4-r\_6)^{-2} - (r\_5-r\_6)^{-2}] = 0$$ Now, you've got 6 equations and 6 unknowns (the radii for each planet), which you can go ahead and solve in terms of the orbital period, solar mass, and planetary mass. The same applies for any number of planets. Once you've done that, you can try varying the radii by small amounts to calculate how much station-keeping force you'll need for each planet. [Answer] Given sufficiently different eccentricities planets with the same year are possible, but they won't stay a constant distance apart. The more eccentric ones spend more of their year in the cold outer dark. If the orbits are such that the semi-major axes are collinear, then I'm pretty sure that the resonance would mess things up in a hurry. Spacing the axes around the circle would give you a solution called a klemplerer rosette <https://en.wikipedia.org/wiki/Klemperer_rosette> This is a known unstable situation. If planets were in pairs, with large eccentricities in opposite directions, and opposite in phase (one is near the star when the other is far) and each pair with wildly different incinations to the ecliptic I *think* you would have a system that is at least short term stable. [Answer] Short answer: **still impossible**. Given the other answers, the closest thing to what you want I could think of was an Earth-like planet captured near a much bigger planet's [Lagrangian point](https://en.wikipedia.org/wiki/Lagrangian_point) L4 or L5. Actually, you can get both and a few large moons orbiting the central giant. Bear in mind that L1..L3 points are unstable, so no more than 3 planets and the central one probably uninhabitable due to immense gravity. (You may need something like Jupiter to stabilize the system, but I can't tell for sure what the limits are). As for your third question, gravitational pull of planets on each other is tiny, however, over long time *anything* unstable eventually gets kicked out of orbit by resonance. [Answer] Yes... if the order of the planets at any time is flexible. If the inter-planetary tethers are strong enough (insanely strong), you could have the 6-planet system spinning about its center of mass, and that spinning system would have a single orbit. If the axis of rotation was normal to the orbital plane, all planets would have the same length of day, which would be the period of rotation of the planetary chain and which is arbitrary above the minimum required to prevent gravitational collapse. [Answer] First of all, see [Kearsley's answer](https://worldbuilding.stackexchange.com/a/98107/37815) for the general formulas that will provide you with all possible solutions (he has my upvote for that). This answer gives a *simple* configuration that includes six planets and should be reasonably stable (= require only minimal amounts of corrections): You have * one sun * two big planets (a bit heavier than earth but less dense and thus bigger in size so that surface gravity is not too much larger than 1g) * four small planets (a bit lighter than earth but more dense and thus smaller in size so that surface gravity is not too much smaller than 1g) The two big planets orbit the sun in the same orbit, but on opposite sides (they are in each other's L3 point). The four smaller/lighter planets occupy the L1 and L2 points of the larger planets. Thus, all planets and the sun are in a single straight line like this: ``` p1-----P2-----p3---------S---------p4-----P5-----p6 L2P2 L3P5 L1P2 L1P5 L3P2 L2P5 ``` Since all planets are Lagrange Points relative to each other, their orbits are relatively stable, however they will still require corrections from time to time since it's just the L1,2,3 points. --- If you want all planets to be on the same side of the sun, you must use hirarchical Lagrange Points: Once you place a planet in a Langrange point, two new Langrange Points appear, one between the two planets, and on the other side of the smaller planet. So, adding a third, smaller class of orbiting objects I'll call moons, you'd get a configuration like this: ``` S---------------m1-----p1-----m2-----P2-----m3-----p3-----m4 L2p1 L1P2 L1p1 L1p3 L2P2 L2p3 ``` This gives you a total of seven orbital bodies in a single line on one side of the sun. [Answer] As you can see from your picture, they are not at the very same distance from the central star. This alone tells you that the alignment you in have in the picture won't last. Planet A will have a different orbital speed than all the others, and the same holds for all the other planets. Moreover, if they get too close each other, they will end up either crashing one on another or with some of them being ejected out of the system. What you can have (but it is rather different than what you state) is a big central planet with a lot of moons around it, a la Jupiter. But they won't be constantly aligned. [Answer] The diagram you gave with the six planets in a line is not possible because of the huge forces involved. If the technology existed to tie planets together like that the tidal forces would make them not usable as planets. Their shape would be distorted and holding them together to maintain spheres would require extra technology. I suggest six planets of equal size and mass surrounding the sun spaced 60 degrees apart sharing the same exactly circular orbit. This is like a Klemperer rosette as mentioned in other answers. They key in this case is having the massive sun at the center instead of empty space. That makes it so that each planet has two adjacent planets in its L4 and L5 points making this configuration relatively stable. [Answer] Although other answers are right, it is possible to have several bodies orbiting a star with the same period while keeping close to each other: usually they are called satellites (all of them except for one). Furthermore, if two bodies are of similar sizes, they stop being a planet and a satellite and they became a double planet. However, if you need distance between planets to be fixed in order to place an space elevator between them, that could be done only in a pair of tidally locked bodies - that is, a tidally locked double planet. In short, the system on your question is not possible, but you may have an smaller version of it with a double planet. [Answer] Maybe... But not really if you just have one star. If you had a binary star system where the two stars had equal mass and the distance between the stars was just right to get just the right amount of sunlight, then the region directly between those two stars might be a place your system might work. At the center of mass you would have zone where the gravity of the two stars nearly cancels out. But the equilibrium is unstable. If a planet drifted to one side or the other then the gravity from the star on that side would be a little stronger and make the situation worse. The gravitational potential would look a little like the image below. [](https://i.stack.imgur.com/Ns7GS.png) The y axis represents the gravitational potential energy, the x axis the position and the two stars are located at -4 and +4. Usually, we would want to place a habitation in a situation that is [dynamically stable](https://en.wikipedia.org/wiki/Directional_stability). If a system is dynamically stable, then small changes in the system just result in oscillations. If a system is dynamically unstable, then small changes produce large results. This is like a ball sitting on top of a hill. It will sit there if undisturbed, but any small push will eventually lead to the ball rolling down the hill. If you set things up just right, the additional forces from the stars as you moved either way from the center could balance out the force of gravity from the other planets. I think an electromagnetic tether could be used to overcome the dynamic instability of the system. But this tether would have to be something incredible. A gigantic solar sail might be a good way to augment the tether, especially is the forces from each star would normally balance out. Moving either way would usually cause the net force on the solar sail to be a restoring force, and so we might make the equilibrium a dynamically stable one. [Answer] 1: Probably in the case of 2 or more stars rotating on eachothers axis and permanently maintaining the gravitational pull at a stable output. With 1 star highly unlikely for sustained amount of time (like others before me stated) 2&3: Related to the gravitational balance needed to do nr1 , they can even orbit dwarfs stars or black holes as long as the orbital equilibrium is maintained constantly. But the inevitable alterations in every star/black hole will eventually break the orbits down) If you want to go scify rout go for 3 star solar system (2 big stars and 1 dwarf )the planets orbit the dwarf that is locked in place by the orbit of the 2 big ones. But this solution is a big NO if you ask "is this possible ?" just giving you a possible solution that unless you know the precise math behind it normal people won't notice it at first glance. [Answer] Their might be a way too get something like what you want. If you use the elevator to tether the planets together(assuming specfic strength ) then they will want to travel in the same orbit. (The lower planets will be pulled up and the higher planets down) Now if you have the engines to counter this then they can stay in the seperate orbits. This will cause the non middle planets to have a sideways acceleration though. ]

[Question] [ Let us take a reasonably skilled (i.e. someone who knew their way around the boat as well as how to navigate) ship's captain from around the beginning of the Age of Sail (late 1400s to early 1500s), and teleport him into the modern world. What skills would they need to learn in order to work on a modern-day merchant ship (let us assume we're dealing with a container ship or gearless bulk carrier here to avoid weird stability or cargo-handling troubles, or having to deal with passengers for that matter), and eventually become a captain once again? We can handwave them picking up whatever lanugages they'd need to learn to work on the ship in question, as well as ethnic issues, as modern-day merchant crews are veritable tossed salads. Don't worry about shoreside or cultural matters, either, as they're beyond the scope of this question. [Answer] ## My qualifications I was a qualified Officer of the Deck in the US Navy. I have around 2000 hours watchstanding time and about 50 port and anchorage transits. ## Navigation skills A (competent) 1500s sea captain's navigational skills would be much higher than any modern day sailor's, just due to the lack of technology at the time. Modern navigation is, of course, done by computer. You will plot your navigational position by GPS and soundings (depth readings) by fathometer. Only in the last 5 to 10 years, these technologies have become advanced enough that you no longer need to rely on older methods. That being said, while I'm certain the modern merchant fleets of Maersk and CMA CGM are using all-digital navigation, there are likely a lot of smaller local transports still using older methods. In particular, I know that the majority of non-oil tankers in West Africa are pretty backwards, and a surprising amount of the merchant traffic in the Mediterranean is smaller local merchants. For ships without the newest technology, a lot of what the old sea captain knows would be very valuable. Taking fixes by compass upon entering port is unchanged from the 1500s. Where GPS is not available or broken, the sextant must be used to take fixes from the stars in open ocean. The sextant requires a lot of skill to use; the old mariner's skill with the astrolabe would translate directly with a little bit of training. I can attest that on a modern US Navy Warship in 2010, my captain launched a small boat to sound a harbor to verify depth before we tried to enter. A 1500s sea captain would have forgotten more about this technique than my entire ship's company ever knew. Finally, general knowledge of wind and waves and how the sea looks can be useful in a lot of small ways. I knew a lot more about currents just looking at the ocean's surface after 2000 hours than I did when I started. A 1500s sea captain would know far more still. I imagine there are still a lot of local merchants that don't use electronic charts. In that case, while the old mariner would be amazed by modern chart's accuracy, using them is not fundamentally different from the portolans that he would have been familiar with. In conclusion, for not state-of-the-art vessels, a 1500s ship captain would have a lot of usable skills that could be upgraded with minimal training. Remember, things have gotten easier in the last 500 years, not harder. This old mariner learned the hard way. ## Not prone to sea sickness It is somewhat amazing how many career US Navy sailors are still susceptible to seasickness after a decade or more in the Navy. Modern ships tend to be very large and stable, but then once in while you are in 20 foot seas and you just have to puke. But seasickness is something you get used to and get over. A 1500s sea captain would presumably be quite immune. Not a huge advantage, but useful. ## Boatswain's knowledge A modern US Navy Boatswain's Mate (pronounced Bosun's mate) has a knowledge base that is largely unchanged for the last 3000 years. How to tie knots in ropes, how to unwind the strands of a rope and remake it into an eye, how to tie things down so they don't fall overboard at sea; these skills remain. Its actually an open question whether a 1500s sea captain would have these skills. For example, Horatio Nelson probably never knew of these things. He was an aristrocrat and learned navigation and the stars and how to maneuver a ship. There were career enlisted sailors (namely, the ship's bosun) that knew these things. Depending on what your 1500s captain did before he was a captain, he may know more or less about these things. ## Conclusion The skills and general acclimation with the sea would make the 1500s sea captain a very useful person to have around. He would need some training with modern equipment, with what GPS is, with modern techniques of marking transit of charts. He would also need to learn from scratch how to direct a ship under power, as opposed to under sail. But given his skill set, it wouldn't be a stretch to hire such a person as a third mate on a 3rd world coast-hugging cargo tramp. [Answer] I'll capture a tangent issue. 1500's captain, assuming, he grew through the ranks, would have a much better understanding of wind and sail. After catching on 500 years of progress in the sail division (modern sails work as plane wings, and such), he'd probably be better off at yachting or something like America Cup than most of modern sailors, even those who do yachting. A further issue would be basics of his time's shipbuilding (interesting for history professors and collectors) and his expertise in general seafaring of that time. Imagine, someone in Hollywood would like to make the most historically accurate pirate movie ever, the 1500's captain would be an ideal consultant. [Answer] Modern fleets and nations require serious qualifications for all officers, including Captains. Typically you're required to have academic qualifications of a specific nature at something equivalent to Bachelor's Degree level and have a lot of experience in the roles leading to Captain, as well as all the paper qualifications required for those roles. It would be the equivalent of several years work (that's voyage time, not employment time). If you don't have these things no serious shipping operation would hire you and no government or insurance company would permit you on a ship in any capacity as a responsible officer. And don't underestimate the power of insurance companies in this - uninsured ships and cargo are not an viable option for anyone in business. [Wikipedia gives some guidance](https://en.wikipedia.org/wiki/Sea_captain#Licensing) but it does vary somewhat. Some more info [here](https://study.com/become_a_ship_captain.html). Prior experience from the 1500's would probably be next to useless to gain these things. Your 1500's sea captain would probably have to start again from the most junior levels and qualify. It's possible if he had a natural talent for this it might help a little, but the formal systems in place mean the formal qualifications and working time requirements are basically not optional. More to the point, your 16th century Captain would have enormous trouble adapting just to life in the 21st century. I suspect they'd be overwhelmed (just as we would if we had to live in the 16th century). Culture shock would kill them, as like as not. [Answer] He could become captain of several sail ships that are still in service. They are mostly recreational and/or training ships, but skills needed to sail them did not change in last few centuries almost at all. [Answer] What would he need to learn: Power engineering. Wouldn't need to be a engineering watch capable, but the whole concept of engine and propulsion. It would be likely sufficient to help tear down and rebuild one of the raft of small engines on a ship. Would also need some introduction to how a propeller works. Possibly done with the aid of one of the small craft on board. Electricity. He knows *nothing* about this coming from 1500, and would likely consider it magic, at least initially. Spending a few weeks as the gopher for the ships electrician would help. Communications. The whole idea of radio would be more magic Ships engine room telegraph. Manoeuvring with screws. The momentum of a large boat taking miles to come to a stop. Necessity of both tugs and pilots in many ports. The idea of dangerous goods -- various chemical hazards, holds that are deadly to enter. Customs and borders. Crew rights. Mixed sex crews. The non-necessity of sails, and the way that wind can push a large boat around. [Answer] Something everyone here seems to be forgetting: ## Marine Law Even if you were skilled enough to do so you can't just grab a ship and merrily head out for the open ocean... ]

[Question] [ **Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- This question does not appear to be about **worldbuilding**, within the scope defined in the [help center](https://worldbuilding.stackexchange.com/help). Closed 1 year ago. [Improve this question](/posts/207858/edit) This is a bit of a meta question, but not the sort I can see in <https://worldbuilding.meta.stackexchange.com/> so I'll leave it here. I love my job, but I still love worldbuilding more. Can I monetize this somehow? What options are there to become (at least part time) professional at something minimally related to worldbuilding? [Answer] **When can an artist become a businessman?** A very long time ago I remember watching an episode of *The White Shadow,* a show about an urban high school basketball team coached by an ex-pro. The episode sticks out for having the Harlem Globtrotters... but I never forgot the point the episode made. [Here's a Youtube clip from the episode](https://www.youtube.com/watch?v=wiy83SYgp_o), but leave it to someone to only show the basketball and not the final scene that made the point! The kids meet the Globetrotters working at a car wash and make fun of them (not knowing who they are) for not being "basketball stars" like themselves, but rather, "manual labor." They're challenged to a game, and the game is fun to watch (those guys make basketball look so *effortless*). What the clip misses is the last sequence when the kids shut out the lights and run away from the obviously better players. When they're coaxed to return to the court, the Globetrotters are in uniform. No wonder they were being beaten! And that brought us to the point of the episode (and the part that's salient here). The coach had the Globetrotters introduce themselves. They did, each giving their name... *... and their college degree1...* **Cool story, grandpa, what's the point?** I'll be honest with you, unless you were born with an unholy talent for worldbuilding, you can't just quit your day job. Here on this Stack it's all about creativity and having fun. *But in the real world, it's about results, deadlines, and the bottom line.* **Artists have always needed patrons** The simple reality is that you can't easily peddle worldbuilding on the side of the street any more than you can art. Oh, you can busk for donations, sell at fairs, yada yada yada, but if you want a *profession,* then you need to be (must be!) as much the businessman as you are the artist. *Why do people buy art?* And that's "art" in any form: music, writing, movies, theater, paintings, sculpture... worlds.... There's a lot of it out there. There always has been. The average person buys a little of it. But no one can make a living on onsey-twosey sales. That means you need to build one world that's whomping valuable, or you need to build a lot of worlds and make a little off each one. Practical business... it's a harsh task master. And that brings us to those college degrees the Globetrotters have. We can give you pointers, but in the end, what you're doing is *developing a business,* not worldbuilding. In my experience, if you don't think of it like that, you'll be a starving artist. What kinds of degrees are useful? * Creative writing * Engineering (problem solving!) * Business management * Data Monetization * Entrepreneurship I know that what you want to do is spend your time building worlds — but you'll need to spend as much or more time building your business. If you hang your painting up for the world to see and expect it to sell, it'll take eons to sell (the world is full of paintings with little "$100-" stickers on them. They're in restaurants, truck stops....) You need to find channels willing to distribute your art and ways to present it enticingly. That's where all those degrees (classes...) come in. It's not that you need all the degrees, only that you need at least one degree to teach you how to learn so you can learn what you need to know to solve this problem (it's just another worldbuilding problem, after all). **I like @TerranAmbassador's answer, I just wish he'd/she'd fleshed it out** The classic solution is to be hired by somebody to help build their world. Video game designers are at the top of the list, but so, too, are authors and movie production companies (and the subsidiary companies they depend on). This is the classic 9-5 paid job where someone brings you and idea and you're expected to flesh out that idea. It's what a graphic illustrator is compared to full-on-canvas painter.2 But we live in a world that has amazing grass-roots solutions. As TerranAmbassador suggests, you can make money *indirectly* by advertising to people who visit your website, youtube channel, blog, etc. to enjoy your creativity. Unfortunately, this usually requires building a considerable world for people to enjoy, and presenting that world in a way they will enjoy, before they'll show up in numbers great enough for you to quit your day job. In that regard, it's not a whole lot different from writing a book. You're going to make (for a book) \$0.35-\$1.25 per copy depending on the size and nature of the book and your contract with a publisher or distributor. To quit your day job you need to sell 35,000 - 60,000 copies. Now we're back to those degrees. Because unless you're already rich, you need to know... * Sales * Marketing * Social Networking Etc. I don't want to get you down about this. I've met people who looked at this mountain, took a deep breath, and pushed forward *hard.* And made millions. Why can't I do it? Because my interests are too diverse to allow that kind of focus — said another way, I'm unwilling to pay the price. **If you're looking for an *easy* solution, it's unlikely anyone can help you.** But if you're willing to pay the price, I think an entire new arm of questions for this Stack can help you. There aren't just a lot of engineers here, there are marketers, authors, publishers, businessfolk... I think there's a lot of talent on this Stack that can help build and develop a career in Worldbuilding. Which leaves as a final question, *do you have what it takes?* **OK, one last thought...** From my experience as an engineer I can tell you that people do NOT pay for creativity. They pay for solutions. Creative solutions get the best pay. But the "creative" part is a distinct second place. From that perspective, you could monetize fully fleshed out *chunks* of a world. For example, a creature. Full art rendering, complete description. Pros, cons, attack values, defensive abilities, contribution to the ecology, the works. And then you start pitching the creature to the film and game industries. The role-playing industry, etc. Or you create mini-worlds (aka "game modules") for role-playing games and license them through the various RPG companies. That's still a pretty big industry, and that's likely the easiest entry into the world of professional worldbuilding. Just remember, people generally don't pay for cool ideas. They pay for working solutions. A cool working solution gets a premium. --- **NOTE:** I couldn't help it, when I saw this online, I had to include it in my answer because I remembered @Nick012000's comment. Ladies and gentlemen, I give you... *[Crown of the Oathbreaker](https://elderbrain.com/collections/crown-of-the-oathbreaker-5e-dnd-adventure)* from ELDERBRAIN. A 916-page "module" for Dungeons and Dragons 5e. I've never played a 5e game... I cut my teeth on "version one" — you know, the one in the box with the crappy dice that chipped each time you used them. Oh, I played the books for years (and I'm a proud owner of a copy of the original *Chainmail!*). But the idea of owning a single "module" that would have required *my entire childhood* to play... that tickles my fancy. Yup, it's AD&D. You'd be hard pressed to make money making modules for [Gammaworld](https://en.wikipedia.org/wiki/Gamma_World), [Twilight 2000](https://en.wikipedia.org/wiki/Twilight:_2000), or [Paranoia](https://en.wikipedia.org/wiki/Paranoia_(role-playing_game)), But the world would be a better place if you did! --- 1 *Not all Globetrotters have college degrees, but most do. They had to. They're successful because of enormous talent, hard work, and better-than-average thinking. College degrees teach you how to do that third item and help tremendously with the second.* 2 *And you should expect the envy/contempt behavior. As in the oil painters have enormous contempt for graphic illustrators while envying their cash flow, and the graphic illustrators have enormous contempt for the oil painter's failure to monetize their talent but all the envy in the world that they're painting on canvas.... It's a stereotype, but I've seen the perhaps unconscious behavior all too often.* [Answer] Modern "storytellers" in the industry only care about what sells these days. Sadly, worldbuilding isn't one of them, especially when you're working for someone who wants the job done in their own specific way and you have to adjust your input to match their agenda, irrelevant of quality. To cut a long story short, barely anybody these days actively seeks out consultants for quality but rather demands experienced yes-men in the right places and with the right connections to pull as many strings and push anything they throw on their plate. That's just the way the world is, it's not corruption it's lobbying. If you genuinely love worldbuilding, your best bet is to set out on your own to attempt creating a world that suits your imagination and your reasoning... and hope the bigshots notice you and the thought of using your franchise as a vessel for profit crosses their mind. Personal note: I've been working on my novels for 15 years now, I published my first book 6 years ago and my 2nd book should be published by the end of this year, I consulted multiple publishers and distributers with my concepts and pretty much everybody shot me down because I'm either too young, too inexperienced or too "unknown" and that actually gets me labeled as a high-risk investment. Had I not decided to turn to self-publishing I probably would have burned all of my work ages ago and tossed my fantasy world to oblivion. I don't expect to profit from my work during my lifetime and I don't expect anyone else to do so after I'm gone, my main goal is to leave a legacy behind me and perhaps something I will be remembered by or maybe even mentioned in the passing every once in a while. [Answer] As I see it, you've got a few options. You can monetize your worldbuilding indirectly by, say, making a game or a writing a book set in your world and selling that. One artist that I know of, [Abiogenesis](https://www.deviantart.com/abiogenisis), is putting together an illustrated encyclopedia/visual guide about their world. You could also *directly* monetize it by, say, starting a blog or a wiki and starting a Patreon page to go with it. [Answer] Considering the question is *how* to make money using worldbuilding, not whether it is possible, or whether books are the right medium, here are some suggestions: * Start self-published and free, to create a community. * Don't exclude any format, not everything needs to be a 1000 page book right from the get-go; you can start with mini-series unless you already have a lot of material. * From the beginning, have a strong social media presence; i.e., a YouTube channel or something like that. Show whatever you are doing there, in real-time. * Branch out to diverse media; maybe create a tabletop wargaming version of your world, or a boardgame, or a pen&paper RPG. Maybe try to get into these areas yourself, or do collaborations with other creators. * Generally, have the best presentation as you can. If you check out some hobbyist creators on the verge to being almost "pro", you can witness that the technology is really available to everybody with a passion and a relatively small investment (cameras, microphones, but also in the self-publishing space regarding books, e-books etc.). * Check out Patreon for some direct peer-to-peer funding. * At the beginning, you'll need to keep your day-job, but eventually, if your worldbuilding finds an audience, you might just make the switch completely. As you can catch from the other answers, classically published books are probably the most frustrating area, but there definitely are other routes. [Answer] Considering that the key here is "part-time", you could become some kind of... # **Meta World-Building authority** You might have yourself a hard time becoming a "world builder" for others, but you could become someone other world-builders look for when in need. You could: 1. Create a YouTube channel. Make analysis about successful and failed worlds on famous franchises. Describe the rights and wrongs they did. There are some channels already doing something like this ("Terrible Writing Advice" comes to mind), but they usually are focused on more general topics. 2. Write books about world building. Give advice to novices and experts, write "rules" about what to do and what not, what to look for and what to try to avoid when building a world. You could create books focused on diferent types of media. This would help you to make yourself known, and maybe, eventually, let your own work be more appreciated. It's not going to be easy, of course, and at first you can expect a lot of people not take you seriously. That's why I would recommend focusing on begginers first; people looking for some kind of advice on how to start on their own. [Answer] I don’t have a better answer than others to this question. But, I’d like to share some observations I’ve built up over almost 30 years of world building for myself and for others. ### Price A self-employed friend who freelanced under his own shingle gave me the advice that your hourly rate should be no less than double what you require to survive. So, if your expenses are 40 thousand USD a year; you should be planning hopefully 2,000 hours of billable work at 40 USD per hour. This rule-of-thumb is reinforced by housing contractors, who generally spitball a job (including parts + labor + warranty) at double the cost of parts and materials. I tried myself for about five years underselling this rule to “compete on price”. What happened to me is this: there was never enough money to grow. ### Marketing and Sales I’ve worked with a lot of companies, and all of the successful ones I’ve seen have no less than one-third of the staff committed to sales. Most of the really healthy ones are around two-thirds sales and one-third product or service. Marketing is about researching who might buy from you and figuring out ways of getting to them. This can include standing up completely unrelated activities (like blogs, or video streams, or free giveaways) and letting it be known where your for-a-fee world building offerings can be found (take Google’s search engine to sell advertising for an example; but there are countless more) You could, for example, rent out a stall at the nearest farm market or go to county festivals selling your world building services on the spot. It might work better in places with higher population density where you get in front of more faces. Isaac Asimov wrote a lot of free or cheap stories to get people interested in the worlds he built. Sales is actually closing the deal. (See where doubling your cost goes?) ### Simplicity Because a pittance of your time goes to your product, successful product or service (ex: world building) starts are usually as simple as possible. Netflix started as a service that mailed you CDs. ### Financing Alternatively, you can get a high-production-value idea in front of an audience by doing a lot of first-class work at a loss. But, to do this, you have to find someone willing to pay the bills. It can be a full time job finding people to fund you. [Answer] There are some good answers here. The hardest part about monetizing it would be getting the word out to people that your product even existed. If you're world-building specifically for a role playing game, then you're going to have to become an online authority for that game, *or team up with someone who is*. Now consider something like "Greyhawk". You'd build out your base world. Maps of the known areas, major players, and so forth. Several compelling adventures. By leveraging your partner's community, you could begin selling the base kit. For your Patreons, then: You could also create custom adventures and related world-building bits per their specifications. Or more extreme, design entire map areas to specification. You could write fiction in that world, to their specification. Imagine a serial where the week's gaming session is made into a chapter of a book. [Answer] What is your market? Here are a few: * World building software: Earth Sciences Put in parameters, and it generates a detailed map, runs at least a simple climate model to give you the seasons, the norms, the extremes. Target: writers and would be writers. This software can do your physical world -- continents and weather, given the brightness of the sun, inclination of the planet, rotational stability. Sell a basic version of this program then do consulting with special programming for adding a sun, rogue neutron stars, ringworlds etc. * World building software: Economy. This is one that often is badly done in SF. Either the economy is a copy of our own, or it's vague. E.g. The population numbers, and the effort required by dragons never fit on Pern. 3000. In Startrek replicators are nearly universal and appear to be based on molecular assembly much as trasporters are.. Why all the concern about gold pressed latinum. Why can't ships be mass produced by BIG replicators. * Writers in general who don't know about this stack exchange. Put an ad in writers digest offering help working the kinks out of their world. * Script consultant. Would that Hollywood actually used such more often. Check the science. Make the numbers consistent. (This always drove me crazy on startrek. Many shows have a "bible" of how things work behind the scenes, what relationships are forbidden. SF and Fantasy shows haves ones with some of the lingo, and if good, the limitations on the technology. While this is a very needed process, marketing to this sector would be a bitch. [Answer] ## Worldbuilding books exist I thought it might be useful to note that there are **commercially successful books that are almost entirely exercises in worldbuilding**. So there is some market for it and a few authors have made money doing it. It's probably not that big of a market, and it seems to be mostly geared towards kids and young adults, but here are some examples. A book I loved as a kid was **Spacecraft: 2000-2100 AD by Stewart Cowley.** I was able to find it through [SciFi SE](https://scifi.stackexchange.com/questions/199953/fictional-graphical-history-of-spaceflight-book-from-early-1980s-that-covers). The book is a basically a bunch of beautiful paintings of fictional spacecraft with specifications, details and history about the use of each and, for military spacecraft, their exploits. There's no plot to speak of, just some references to a war between Earth and its ally (Alpha Centauri) against their enemy (Proxima Centauri). Apparently there was a [whole line](https://en.wikipedia.org/wiki/Terran_Trade_Authority) of these books. A lot of other **books with mostly worldbuilding content are related to existing universes**, such as fictional reference books for the [Star Wars universe](https://www.goodreads.com/book/show/35421.Star_Wars). Obviously, the author's creativity is a bit constrained since they have to be consistent with existing canon, but I'm sure they get to invent a lot of the details. **Given that there is an already existing fanbase for these fictional universes, my guess is that this is where the money is if you want to worldbuild for a living (what little money there may be).** I'm not sure its easy to get into these types of gigs. It looks like the [author](https://en.wikipedia.org/wiki/Haden_Blackman) of that Star Wars (Haden Blackman) example started out by writing worldbuilding [books in his own universe](https://www.goodreads.com/book/show/373026.The_Field_Guide_to_North_American_Monsters). [Answer] I will suggest Web Serial + Patreon because I actually have some data on it. There is a web serial named The Wandering Inn, it is a rpg lit novel and the author releases one new chapter every week. Those who support him on patreon get early access to the releases. The author PirateAba has to this date, 4756 patrons. That is already a good amount of cash per month (If you consider a minimum of 1 usd per patron). He has some other novels but the Wandering Inn seems to be a hit. And it is free! You can read it all if you wait for a week, but he has tons of supporters that love his novels and the universe he created. As someone living in Brazil the sum of 4756 usd converted to Reais amounts to 25.250,00. That is crazy, as the minimum monthly wage here is around 1,100.00 (x25 times!!). He would be a very wealthy individual here, this is the salary of a state prosecutor. So, make your idea into something entertaining, like a novel and find people who love it enough to keep it alive. Best luck! [Answer] The simple answer to this is that you find some people who are both interested in producing a quality product where the world is going to be more than a one-off, and talented at all the "non-worldbuilding" portions of the task, but not good enough at the world continuity to do that bit on your own. Then you collaborate with them and split the profits. It's actually a fairly common arrangement. For example, in the movie business you'll find such people credited with variations on the word "continuity". They may or may not actually be good at it, but there's usually at least somebody trying to make sure there aren't too many glaring errors in the story's backdrop. Just keep in mind that most stories are effectively one-offs. Nobody's going to pay you much to create a whole, detailed, self-consistent world for a story that's not going to showcase it. So you'll be hunting around looking for people who want to write epics and need the background designed well enough that nobody mocks them for inconsistency by the end of it. Also note that it's going to be rather like acting or singing or other creative pursuits. The top 5% make good money. The top 15% can support themselves at it. Everyone else gets to have it as a hobby that hopefully doesn't cost too much. If you're talented at more than just the worldbuilding part, your best bet is likely to start out creating the whole story, either by yourself or with a small group of collaborators, and then once you get something popular consider licensing use of the world to other authors on condition that you have final approval of the world additions and mechanics. This is basically what's done with various popular franchises and can work rather well if you can manage to become popular enough. [Answer] Other answers expand on worldbuilding as literature, as fiction. Worldbuilding is "[...] using science, geography and culture to construct imaginary worlds and settings". Because you ask for "something minimally related to worldbuilding", perhaps you'd like to consider work interpreting worldbuilding as "[...] using science, geography and culture on real and imaginary settings to construct a world as a result". That is, analysis, futurology, product development, and so on. [Answer] ## First of all, *what* is a "professional worldbuilder"? OK, so you want to make money by world building. Not by story telling, just by world building, which is nothing but *one* of the preliminaries of developing a story. What exactly is it that you do? * Do story tellers come to you and order a bespoke world? For example, suppose Mr. [Anthony Hope](https://en.wikipedia.org/wiki/Anthony_Hope) comes to you and orders a small, landlocked, [Central European country](https://en.wikipedia.org/wiki/Ruritania), ruled by a hereditary monarch etc. Will you design and flesh it out for him, complete with the genealogy of the main families going back four generations. layout of the capital and principal towns, economic base, culture including quaint proverbs and quotable poetry, and so on? Well, if *this* is what you do then you are in luck; you are a [personal assistant](https://en.wikipedia.org/wiki/Personal_assistant) (maybe specializing in doing preliminary research) to a writer, possibly a freelance [virtual assitant](https://en.wikipedia.org/wiki/Virtual_assistant_(occupation)), or maybe a creative consultant. * Do you build worlds on stock and sell them to anybody who is interested? How many complete worlds do you have, and of what kind? How many of the Ruritanian kind, how many of the Conan Cimmerian kind, how many of the Barsoom kind, how many of the H. Potter kind? Do you also have reconstructed ancient worlds, or fleshed out future worlds of the Star Trek kind? Well then, in this case all you have to do is put up a catalogue on the Web and decide how you are going to charge for your worlds -- do you want a one time fee, do you wan royalties? You may also want to offer a free sample of your work, so that people can see how thorough is your work. You may also want to provide a detailed quantitative description of what you are selling -- what does a world contain? A map, and at what scale? How may names? How many genealogies? How may city and town layouts? How detailed in the economic base? Do you also include lore? [Answer] * Make shorts on youtube/tik tok You can act them out, draw them or simply read them. Youtube recently made short videos monetizable, so if you can release a 45 seconds short story a week, that can be 20 extra bucks at the end of the month with an average channel, this just from the adds. With sponsors you could make 300 or more per sponsored video. * Make adventure/exploration minigames on the play store, make them free to play with bonuses for watching adds. Today making a game from 0 is possible without any computer knowledge, just watch some tutorials and use free assets. -Make a podcast where you read random stories in your imaginary worlds. You can either do them live on twitch and get donations and subscriptions or sell them individually or to other youtube channels. ]

[Question] [ You've probably played this game before — the hero goes out into the wilderness, slaughters hordes of beasts and bandits, then returns to the town and promptly sells all his loot to the nearest shopkeeper. This is fun for a game, but it's far from realistic. A shopkeeper isn't going to want to buy 50 leather helmets, though the local militia might be interested if they're seriously under-equipped. So what would a realistic economy look like? --- In the scenario that I'm considering, there is a town (around 5K people, perhaps?) with medieval-level technology. It is well known that magic exists, but there are not any people capable of harnessing it. Monsters exist, from the not-so-dangerous to the ridiculously lethal. Magic was introduced into the world a century or two ago by unknown means. A lot of people were killed by the monsters, but eventually a safe area was found. For some reason this one particular area repels monsters, with the more dangerous a monster is the more it is repelled. That's where the town is built. The town gets by, but it's no cakewalk. The town was built as compact as possible, so monster attacks don't happen in town. Most of the land around the town is farmland, but the safe area doesn't completely cover them — farmers have to watch out for low-level monster attacks. There are watchtowers (elevated wooden platforms with a simple roof and a ladder) at strategic points in the fields that allow the town guard to help watch and assist in fighting off any monster attacks. While skilled, the members of the town guard are still only normal humans. The town can't expand as there's no way the guard could continually fend off the stronger monsters that live in the surrounding area. There is no contact with other towns. Traveling is far too dangerous to make it to any other towns without becoming monster chow. *Enter the hero.* A man is spotted stumbling out of the wilderness and taken by the guard into town. He doesn't remember how he got there, but they're not going to throw him to the monsters without cause. He starts out weak and unskilled, but starts getting stronger and stronger. He also develops the ability to use magic. It doesn't take long before it's clear he's "the chosen one"™ or something — he's actually capable of surviving long enough in the wilderness to do some legitimate exploration. So now the hero can go out exploring and bring home nice shiny loot. However, I doubt he'd be able to grab whatever random objects he finds and sell them to any shopkeeper he wants — supply and demand is probably still a real thing. I'm planning that he will be able to find things that are actually useful, such as materials for producing better equipment (for himself and the townsfolk) and one-time-use spellbooks that will allow other people to use magic (though not on the same level as the hero). **Starting out with a medieval economy where almost everyone is just getting by (so disposable income is pretty much nonexistent) how would the town's economy evolve to handle a guy who is eager to dump his entire load of (moderately useful) loot?** [Answer] Basically, to have a more realistic economy, you need two things most games don't; realistic human carrying capacity, and realistic supply/demand models governing prices. In D&D, someone with the maximum base Strength stat of 18 could carry up to 100 pounds without it affecting his mobility and running speed. In reality, even the most physically fit humans are more like a 13-14 on the D&D scale; able to carry up to about 50-60 extra pounds strapped to their body or back before real mobility is a problem, and a real upper limit of about their own body weight (150-180 lbs), and only for short trips. So, in your world, you need that more realistic carry limit, to avoid the hero walking into town carrying 5 full suits of armor on their back in a single trip. More likely, he might be able to carry one extra suit of armor he got as a battle trophy off his dead opponent, if that's all he was carrying beyond his own weapon/armor, food, a few potions etc. Secondly, the fifth time your hero comes back into the armorer with a spare suit of full plate taken off of some undead knight, the armorer's not going to accept it. He has nobody to buy the other four suits the hero dragged in. Practically every computer fantasy game ignores this in the interest of simplicity and fairness in pricing. In a "real" medieval magical fantasy world, if an entire adventuring party walked into the armorer's with a spare suit of full plate each to sell, either the first guy to walk in would get the fair price and everyone else would be turned away, or everyone would get shafted for a fifth or less of the armor's true value. Not fun. But, that's supply and demand. The armorer might make better use of a few helmets and mail or breastplates from each of the characters, that he could mend, shine up and sell to some of the more well-off townsfolk, to use if they're called to arms by the local noble. Demand for a 75-pound suit of full plate, on the other hand, is limited to the two or three knights that have sworn service to the noble. Best-case, it's good raw material, but that's all the value you'll get for it; it's *too* rare to be worth anything (kind of like trying to fence the Hope Diamond). This will also apply to buying supplies with gold. If a hero uses a single town as his base of operations long enough, soon the town will be awash in gold and silver but starving to death because the hero's buying all the bread and ale. The armorer will also be out of arrows and crossbow bolts (realistically those are only semi-disposable items; the average wandering hero would be ripping his arrows back out of their targets where he could instead of the more fire-and-forget nature of most games). There won't really be anyone the town could trust to take a wagonload of gold to the next town to buy food, and that would be a dream target for bandits anyway, so the town might pay the hero some of his own gold back just to escort the wagonload and come back with things the town can actually use. Over time, as implemented in a game, these economic shifts will encourage the hero to do two things they would normally do in a realistic setting: be less of a pack-rat, picking up only what's truly valuable either because he can use it himself or because it's useful to the town, and leaving the run-of-the-mill drops alone; and roaming more, going from town to town doing what needs doing, and spreading out the wealth he finds in his adventures across several towns without draining their resources. **EDIT:** I still think the above answer holds in general, however I wanted to add that I finally joined the 21st Century of video games this Christmas with a PS4, and I've found [The Elder Scrolls V: Skyrim](https://en.wikipedia.org/wiki/The_Elder_Scrolls_V:_Skyrim) to address many of the above points as they relate to the player's experience. The game's role-playing engine has a limited carrying capacity as you might expect, which your equipped weapons/armor and other "field gear" like potions count towards, thus requiring a balance between what you carry out into the field and what you expect to bring back. D&D does this, but many older video-game RPGs like much of the Final Fantasy universe do not, imposing only fairly artificial limitations typically based on hardware limits. More interestingly, the engine also has a limitation on merchant goods and gold supplies as well as their selection; the merchant's objective is, of course, to sell things, not to buy, so they don't keep a practically limitless "till" for the player to drain by offloading goods. They also tend to specialize in the type of goods they deal in (can't sell armor to a food cart vendor), and they can't make things instantly; at the very least they need the raw materials and some time and effort to craft the item you want, which they can't do while they're dealing with you over the counter. This requires the player to "spread" both purchases and sales across an entire town's merchant class. It also often requires going to other towns to find merchants with more coin (or stocks of needed items). The alternative is waiting several in-game days for a merchant's stocks and gold to replenish, a simplification of the basic fact that the economy of the world does not revolve around only you. Of course, the more you interact with various characters including buying and selling from merchants, the higher your "Speech" skill attribute grows, and coupled with level-based "perks" that you can spend on the Speech skill tree, it's possible to increase merchant wallets and sell almost anything to almost anyone. But, because these things theoretically require you to *play the game* to build them up, you tend to get these benefits late in the story, and so the skills are largely a way for the designers to impose meaningful limits on trade without them becoming overly burdensome late in the game, when the player's trying to sell equipment and weapons worth thousands of gold pieces while merchants only keep some hundreds around to trade. You can, theoretically, "break" Skyrim as a game by grinding very early in the story (and exploiting a few bugs in the save engine) to attain an extremely high level and well-developed skills trees before even completing the first few quests, making the challenge of the early game that's tailored to limited player ability practically nonexistent. As a minor additional point, in *Skyrim* you can in fact rip some of your spent arrows back out of your victims (or nearby trees or off the ground where they landed), on top of looting your enemies' quivers. However, this quickly makes ammunition a non-issue; I have thousands of arrows of various serviceable qualities (they are technically weightless), and while I conserve the best ones I have, I'm in absolutely zero danger of not having any arrows at all (I'd just be forced to use the crappy ones that don't fly as straight). [Answer] Honestly, supply and demand doesn't make much sense here. The townsfolk should recognize quickly that the hero is their hope for getting out of this monster problem; keeping him equipped should be a community project. Once the hero has proven himself, the village should give him the best weapons and armor they have (which are probably pretty terrible, but still, they're trying). Then, when the hero hauls some new material back to town, he has to go talk to the local blacksmith and say: "what can you make me with this?" If the blacksmith charges a fee at all, it's probably "I get to keep some of these raw materials you brought me for myself". People are spending time and labor on equipping the hero, and he does have to compensate them for that, but he's probably "paying" for it in food. Whenever he kills something in the forest, he hauls the corpse back as fresh meat. The town saves a bunch of labor from having a steady supply of meat, and that's enough to cover whatever labor the hero needs. I imagine eventually the hero has his own collection of workers: the hero's armorsmith, the hero's weaponsmith, the hero's leatherworker, the hero's sage. When he hauls something back to town, he holds a meeting and says: "here's what I killed, here's what I found, what can you make me?" Anything they can't use to make stuff for him gets given away, because the villagers are dirt poor and couldn't pay for new arms and armor. So essentially the hero is creating his own economy, by hiring people to train themselves to make things he needs. [Answer] First of all, let's realize several things: 1. RPGs are simplified because fighting/looting is basically the pc's main source of income. GPs from missions/quests may be substantial, yes, but you'll find yourselves unable to buy stuff fast if you don't regularly loot fallen opponents. 2. In order to facilitate that, *every* shopkeeper in an RPG world will have a seemingly inexhaustible source of currency. No matter how many you bring back, he'll buy at market prices. The market prices will never vary too. How will these things work in a 'realistic' fantasy world? The simple answer is: It doesn't. Unless the character is magically strong, or has a 'Bag of Holding' containing a 'pocket universe', then weight is a real issue for the adventurer, as it is an issue for the modern Soldier or even hiker. Consider: For a person to be able to spend a significant amount of time in the wild hunting monsters, he will need to carry everything he needs to survive on himself or his pack animal (which is NOT his riding animal). He needs to carry some amount of food (which he can supplement from local game), some water (depends on the climate of his Area of Operation), spare clothing, tent/tarp, his bedroll, medical supplies, hunting supplies, tools. He also needs to carry his weapon/weapons, weapons maintenance/PMCS kits, spares, specialized weapons, etc. Then he has to carry his armor, armor maintenance/PMCS kits, spare parts, etc. All this add weight, that has to be carried somehow. And, if you want to be realistic about it, our hero would not be traipsing up and down the forest in his plate armor all day. Have you ever worn armor? Trust me, its nasty in there. Plate armor is hot, heavy, uncomfortable to wear for extended periods. Its hard to put on, its hard to take off. So our hero will probably be walking around in a padded gambeson with some mail; carrying his expensive, tailor made plates on his mule. He'll put the plate on just BEFORE he fights that Ork boss. As far as loot goes, this is also the case. Say our hero defeats a particularly well armored Dread Knight. Good loot right? Weapons? Armor? Gold? Well, not really. Weapons, maybe. A good sword/shield/lance will fetch a fair price, can be used by just about everyone even if they're not tailor made for the individual, and are relatively easy to bundle up and carry (well, small bucklers maybe. Big shields will be problematic). But that fantastic set of plate armor the Knight was wearing? I don't think so. For one, its heavy. It takes space. Armor (with the exception of mail and the *lorica segmentata*) are generally cumbersome to store, being hollow cylinders of metal. Even if you manage to strip the set off the dead knight, no one else will be able to wear them. Why? Because the best armor are custom made to the measurements of its wearer. And ill fitting armor will be more a liability than protection to its wearer. Even if you manage to take it back to the village, who will want to buy it? Maybe the local noble as a trophy. But that's about it. Its hideously expensive, so the blacksmith probably wouldn't be able to afford it. Nor will the Knights, since they already have their own custom made armor and are already spending a lot of money maintaining it. So maybe you'll just take the set as a trophy to decorate your home. Maybe you'll just take the helmet. You sure as hell isn't going to sell it. With that setting in mind, the best occupation for heroes in your world would be as mercenaries, hired by these frontier towns to clear out monsters every so often paid in gold and loot (what loot they can cart off to sell in bigger towns/market towns). They will definitely not be selling the loot in the hiring town though. [Answer] I would suggest that the best way to handle it is to make the hero a "kept man." The first trade good the hero returns with that no one can afford to buy is gifted to the lord/king, the hero gets knighted (and eventually is named Hero of the realm) and no longer participates in the regular economy. Free meals and lodging anywhere such is available, the king may commission special equipment (everything from suits of armor to the finest horses to squires) for the hero. The problem would be that material rewards available from society are rapidly outclassed by trade goods obtainable through adventuring. In order to keep the hero interested in adventuring with the materialistic carrot, the items found must be of immediate or eventual use to the hero directly. Maybe a spellbook details a process for enchanting a suit or armor, or the creation of a magic sword. Maybe there's a fountain of youth at the bottom of the deadliest dungeon. Maybe a slain dragon leaves behind a single egg to be raised as the hero's pet and mount. Of course, there might be other motivations for adventuring. (Intrinsic spirit of adventure, existential threats to the realm, or even just hoping that "the next leap will be the leap home.") ;) [Answer] They say that something is only worth what you can get for it. In a modern economy of scale many small items get a price set by the market so it appears that there is a 'value' for everything but this is only the case because of the liquidity of currency that is available. But for more expensive items this can break down (a little). You can see this when prices can be negotiated considerably, such as house prices in a downturn or in a boom. There's no fixed price they rise or fall dramatically. The same applies to such a primitive economy. When you arrive with a suit of armour in tow, it can not be worth more than someone else has to offer. No matter what the guide book price might be at the big city that the Armourers to the King would charge you, if you have to sell it to a man who only has 3 silver pieces, then 3 silver pieces is all you can get. In a town as described this might not be money at all but other goods (as barter). The other aspect is value to the inhabitants. A suit of armour may be nice and shiny, but if you're starving, its worthless. Like trying to sell a Ferrari to a place that has no gas. Nobody will take it off your hands, or they might offer you $10 so they can keep their chickens in it. So what would happen in such a place is that the possessions of the inhabitants would increase where they possessed high-ticket-price items, but would not consider them as wealth. A bit like the Aztecs who had so much gold that they considered it just a worthless shiny metal and were happy to trade large quantities of it far in excess of what the early Spanish explorers considered it to be worth. (which is another lesson. If civilisation is every contacted again, and every town inhabitant has 3 magic swords holding up their washing lines, traders will quickly appear to trade goods worth something to the inhabitants for those items. Want a magic sword? It might only cost you a bag of turnips at this town) Some RPG games try to model this as inflation - a suit of armour is worth 100gp but after you're delivered 5 suits to the local smith, the price drops to 50gp. This doesn't reflect reality, and a better way to model it is in terms of the smith's stock and access to raw materials. However, such a system is complex and requires a lot of book-keeping. [Answer] **The Hero is Limited by the Towns Economy, Not "Wealth"** In a regular RPG, the shopkeeper with +5 vorpal swords in stock won't lend you a rusty dagger to save the town with. A mid level adventurer probably won't have much difficulty persuading townsfolk to part with required items. They could use 1. Good will (Look, I killed the dragon that was setting fire to your crops...), 2. Trade (The scales on this thing alone must be worth a fortune), or 3. Force (You'll call the town guard? I bet they can't even breath fire!) The bigger issue is that, as the hero is the only one regularly finding cool items, whatever the townsfolk have is probably less cool than the hero already has. The hero may find himself building up the towns economy just so they can make things that they hero actually wants. Just hunting monsters to extinction for XP will as a side effect help the town grow. However, if the hero wants a regular supply of truesilver arrows, he'll have to clear the mines out and gift the town guard with magical items so they can protect them from the occasional monster he hasn't already killed for XP. [Answer] Deep in the wilderness there won't be much loot to be had. Even if there are other villages nearby they'll probably be in the same position - impoverished and barely getting by. He could hunt and bring fresh meat as well as other resources such as wood etc. He can find rare ingredients for the magic potions of the local alchemists / magicians etc. I don't think he'll be able to sell them to the "shopkeeper" - there will be very little trade going on, most peasant will be self sufficient and won't have any disposable income. All of his loot will be luxury goods that no one would be able to afford. The only option is to trade those things to the local lord in exchange for housing, inclusion to the local court and preferential treatment in general. If you look back in history, people who were allowed to eat at the lord's table were a big deal because pretty much everyone else starved. [Answer] I can't make a comment due to my low reputation, but I'd like you to take a look at the game Recettear. Don't look at the story or how the game looks like if japanese games aren't your thing. But the gameplay could interest you : it's about being a shopkeeper that have to follow the demand, make a lot of money, etc. And you're also forced to go in the dungeons to have our own stock. But your inventory is limited so you can't carry more than 20 items. So, you have to make choices in what you will bring home, what the customers will buy, etc etc. Take a look at this game, I think it will inspire you if you don't know it yet. **EDIT :** To explain a little more, like @bilbo\_pingouin asked, the game is about being a shopkeeper. You have a debt from your father that you have to pay, and you have to pay more each week. So, what you sell are items you get from dungeons. You explore dungeons with adventurers (not the important part of the game) and you get items. To make a link with the other answers, here, you're able to carry only 20 items (even if, in theory, you could carry 20 elephants or 20 candies). You will be able, then, to sell (or not) the items you got from the dungeon in your store. There's a way of promoting certain items, but it's not relevant here. Then, you have your customers. Some of them will make some orders they will get 3 days later, some will buy in store, etc... And some will try to sell you things. So you have to buy low and sell high, which could help you, for your problem, to see what could think a shopkeeper in this situation. And as you said, there must be supply and demand. In this game, sometimes, the demand will go very high for certain items, so you can sell them at 500% or something of their original price. Or the demand will drop and nobody will buy it, or even worse : they will ask you to sell it to them at a cheap price (so you don't make a profit AND you lose the item because you sold it). For all these aspects, I think it could help you a little to see what could a shopkeeper wants when it runs its store. I hope I was able to be understood. [Answer] In the rush for economics, everyone seems to be missing a few basics. Which in my experience is about par for the course for economics as a subject, but anyway... Beasts don't drop helmets. Furs and hides are *always* a useful commodity. In a fantasy context, various other bits of beasts (bones/teeth/blood/whatever) may also have value, and would be sold in the same way. And for beasts with edible meat, a town-sized free meal will go a long way to making the hero popular, or can be preserved (salted/dried) if appropriate. Beasts are either rare (e.g. basilisks) in which case there aren't enough to make over-supply an issue, or they are common (e.g. wolves) in which case there will already be an established trade for their skins and a bunch of other hunters also selling them (including hunting in the same area as your hero). Of course this might lead to your town making roofs from dragon scales instead of wooden shingles. No matter - dragon scales are only useable by magicians in the city, and your scenario prevents any trade with the city. Bandits are a different situation. Let's think about the actual items first. The "50 leather helmets" scenario is as fake as the "weapons store that buys everything". Bandits are most likely to have home-made bows, spears and cudgels, and any leather armour is equally likely to be home-made and hence not saleable. The most valuable thing you're likely to get from bandits is their clothes, boots and pocket knives, which *are* worth something to regular villagers. Of course a group of bandits who deserted from an army/militia might have some decent kit, in which case an army/militia would probably like it back. They might also have some decent stuff looted off armed travellers, but if you postulate enough armed travellers to outfit a bandit camp then you have yourself an instant market which will take this kit anyway. And then you start thinking about how many bandits there actually are. Bandits staying in one place (e.g. Sherwood Forest) are likely to be disaffected locals. Kill that group, and it's likely to be a while before enough disaffected locals are brave enough to challenge authority again. Other groups will wander from place to place, pillaging villages as they go, which is more typically the behaviour of army deserters, but again there's only so long you can get away with this before either you run into a well-organised militia or you become infamous enough that the local lord/prince decides to stomp you with his army. Either way it's not a receipe for a long career as a bandit, and both of them exclude the likelihood of a career as an actual bandit hunter. And that's before we think about your specific example. If magic has wiped out trade because it's too dangerous to travel, then it's also to dangerous to be a bandit. A group of blokes living in a camp in the woods translates to "low-risk crunchy snack" for your magical beasts. In other words, the limits you've imposed on the scenario will also mean that your perceived problem can't ever happen. [Answer] At first, the hero would be able to get pretty much nothing for his loot. A few days worth of food for a few swords, or two days of work from the blacksmith (fixing the hero's armor) in trade for some raw materials (that full plate armor from all the other answers will be melted down for farming tools). The townspeople don't have anything else to spare, they may not even *have* any gold or silver coins. The only way for the economy to grow in such an isolated place is for the hero to bring the city resources that it can use to increase its production. Arm the town guards with Magical Crossbows of Monster Slaying, supply the farmers with Magic Beans and Golems, and they'll be able to pay... still almost nothing, but at least a little more. If the hero works very hard, giving away all his loot to the town, and is lucky enough to survive the many expeditions, he might retire in a town that can afford to have more of its people producing stuff of value to the next hero. Only if trade with a larger market (the outside world, if it still exists) is established will all of this change. The most valuable loot therefore would be related to that. Saddlebags of Invisibility, anyone? [Answer] Don't neglect recycling value. Sure the merchant doesn't need 5 suits of armour but steel is expensive, valuable and can be used for many things, same but less so for leather/bone/iron/copper/wood/... Maybe that's why in games you can buying armour costs 5 bazillion gold pieces but you only get 7 silver back for selling it; you're buying craftsmanship but selling scrap. [Answer] I suggest beating swords into ploughshares - or maybe scythe blades. In the long run that valuable metal increases the economic value of the fields and other work in the town. Also the boundaries of those fields may extend slightly, even if the town can't expand, because there are better weapons to fight off slightly higher level monsters. That will lead, over years, to more manufactured goods being available to the hero and maybe the town even being able to spare one of their mules to help him bring back more loot. I hope the hero is long-lived. One interesting corollary is that your unbreakable vorpal crystal greatsword of sharpness is considered trash because it's too heavy to use for the normal farmers and it can't be worked by the blacksmith. Maybe the village could use it as a fencepost though. In practice though, the hero's main economic benefit would probably be as a guard protecting workers from monsters and allowing them access to resources they couldn't previously get to - trees in the forest, a trout stream or some metal ore for example. [Answer] The town you describe won't be buying his loot--a subsistence economy in a small town will have little money and what money there is will have to be spent on things of direct value to the people purchasing it. The only things they might consider purchasing from him are supplies--something they are unlikely to have in this scenario unless the monster itself meets that criteria. Expect him to get the value of any monster meat he brings in and if he makes it safe enough they don't need to man the watchtowers then he'll get the labor that would otherwise have gone into manning them but that's about it. They can't trade away what they need for survival, nor would there be anything in town to buy with that money even if they did. The town will of course be grateful and he will get whatever non-cost services they are capable of providing--he will, for example, never want for a place to sleep. Depending on the society he might also never want for a bed partner. [Answer] You ask a fun question. Everyone I think has sufficiently covered the basic economics in play. What I'm offering is auxiliary information. You're talking about a subsistence economy, but with just enough resources to be able to afford guards and guard towers? However shoddily built, this doesn't really sound realistic. If there's enough organization for a town guard, this generally dictates that there's enough of an economy that you can have dedicated guards, and that the common people have enough free time to be able to build defensive structures such as towers. Which also suggests some kind of public government to collect taxes and pay the guards. If you look at history, this necessitates *some* kind of economy beyond hand-to-mouth. Also note that it is *very* rare for all resources to be readily available... so for realism, you really will have to have some kind of inter-town trade. Economies don't exist in a vacuum, and there are always people willing to risk travel for profit. Also note the strategic importance of a town that repels monsters isn't going to go unnoticed by the nobility, whose feudal job at least will be to protect their fief, and ambition allowing, to acquire territory and defend it. It is highly unlikely that the town wouldn't be confiscated/acquired by a lord and be used directly as their primary base of operations. Having a noble in the town's presence is going to drive the need for more than subsistence goods in order to fund the noble lifestyle as well as all of the support for the lord's soldiers. If you decided to mitigate that by saying that *every* town has the ability to repel monsters, then you're still going to have to deal with the the strategic importance of this... Just like cities tend to be built by rivers, cities and towns will be built on these safe spots if they're big enough. Any aspiring Lord or Warlord is going to be very interested in every one of these that can be found. ]

[Question] [ Explosives as we know them are **exothermic:** they produce heat and light, or, in other words, energy is *expelled*. Let's consider **endothermic bombs:** weapons that, upon detonation, consume heat and / or light and / or nearby electricity. --- Assuming there is sufficient funding to develop and manufacture this technology, and for whatever reason, there is a use for it, **is it feasible to construct a detonated weapon with this purpose?** **If so, where can energy be drawn from, *or* what will it actually do?** Will nearby electricity be cut out? Will the room be drained of all light? Will it suddenly get colder? etc. --- *Please, no handwavium. Also note that "economically viable" as part of "feasible" would be nice but isn't necessary for an accepted answer.* [Answer] ## Gas expansion This [process](https://en.wikipedia.org/wiki/Joule_expansion) is already around us on an everyday basis. It is the thing that makes it rain. When you have a gas closed in some capsule and around it is lower pressure (and ideally vacuum), when you release the gas it will start expanding rapidly with the loss of internal energy, effectively cooling the gas and its surroundings. It does not work same for every gas; for example, `He` and `H` gases have the effect reversed on room temperature (they do achieve cooling on way lower temperatures, however). In the real world, it works in clouds. When the Earth produces and releases hot air, it rises because it is lighter than cold air. The higher you are, the less pressure is around and raising gas expands, which cools it. At the height of ~2km, it will hit the temperature needed for condensation of water gas into water drops, effectively making "clouds" you can see. When it expands higher and higher (it has to be fed from the bottom because heavier and therefore colder gas tends to drop down as a rain), it possibly can make even storm clouds ([Cumulonimbus](https://en.wikipedia.org/wiki/Cumulonimbus_cloud)), which are really tall. At the top parts of that, it effectively expands to nearly vacuum, thus cooling itself A LOT. At that point, a hailstorm may form, which is just extremely cold rain. ## The bomb For a bomb utilising such an expansion, you don't need any reaction, nor ignition, nor any kind of magic. You only need some capsule that will store A LOT of gas that can be released. Upon releasing the gas, it will expand rapidly (thus make the effect of "explosion", pressure wave etc), and it will cool down in the process. If it is released fast enough, it will consume its internal energy for expansion, thus cooling surrounding objects. The problem to make such a bomb is that you need to start with room temperature, high pressurised gas, which is hard to find. If you compress the gas, it tends to raise its temperature, so you need to do it in steps. Also, the capsule that you use must be strong enough to hold such a pressure. That might also be a problem, nowadays used gas cylinders are not really robust and hold too little of gas for your bomb purposes. [Answer] This could be a bit of an underwhelming answer, but it is the best I can do while sticking to realism. ## For absorbing heat One simple solution is to use a device that causes rapid evaporation/sublimation of a liquid or solid. We already have something similar—a bottle full of liquid nitrogen. To make the device better, you can pressurize it to prevent ineffective evaporation, to make the device easier to store. (so that your character can say things like "hey look, this centuries-abandoned arsenal seem to contain some endothermic bombs, we can use that to...") ## For absorbing light The Ozone layer is absorbing ultraviolet light right now—at least on the sunlit side of this planet, hopefully—however, gases like ozone are frequency-specific in their absorption of light, meaning that light of a different colour/frequency cannot be absorbed by the same gas, so a mixture of many gases is needed to absorb a broad range of light (you also have to be aware of re-emission where the energized gas release that energy in a lower frequency). This will be boring, but if the purpose is to block light rather than remove the photonic energy, just use a smoke bomb. ## For electricity I can only imagine this being useful when the target is some kind of machinery that runs on electricity. Traditional EMPs will probably do the job, but if you want to physically reduce the amount of electricity running in the system, try a [graphite bomb](https://en.wikipedia.org/wiki/Graphite_bomb), which will cause short-circuiting. # Some physics/chemistry An endothermic chain reaction is not possible because of this equation: $$ΔG = ΔH - T\times ΔS$$ Where ΔG is the change in [Gibbs free energy](https://en.wikipedia.org/wiki/Gibbs_free_energy), which must be a negative number for spontaneous reactions (those that can go on without people helping along) ΔH is the change in enthalpy, in endothermic reactions, it is positive T is temperature, it will decrease in the case of endothermic reactions, it is always positive because it is measured in Kelvins ΔS is change in entropy, cooling generally means that this value is positive, but it can be negative in the case of evaporation So, these being said, as the endothermic reaction carries on, T will decrease, so no matter what the posivity/negativity of your ΔS is, the reaction will always start becoming non-spontaneous because the effect of ΔS is decreasing while ΔH is positive and constant, causing ΔG to become positive. [Answer] Surprisingly (at least to me, at first) **there really are chemical reactions that both go forward usefully quickly and are strongly endothermic.** Nor are exotic chemicals necessarily required: A classic example is mixing ice and salt to get a lower-than-freezing temperature -- as was done to make ice cream, before refrigeration was available. <http://physicsbuzz.physicscentral.com/2014/06/the-science-of-ice-cream.html> Another example -- one that works fine starting from strictly room temperature reactants are the "instant ice packs" used in first aid (great for sprains); see <https://en.wikipedia.org/wiki/Ice_pack#Instant_ice_packs> The mechanism for what appears to be a violation of the first law of Thermodynamics is that the second Law gets involved, via the Gibbs Free energy: <https://en.wikipedia.org/wiki/Gibbs_free_energy> I don't know of any such reaction that would be much use as a weapon, except against a poor goldfish in a bowl :-( [Answer] The endothermic bomb would be a heat sink. The problem for a point sink is that you can only go to ~0 Kelvin which is not that impressive compared to the exothermic at least ~500 Kelvins. The point sink simply has no "suction" comparable to "expansion" from the heat source. Thus there is no "explosion" from a point sink. Thus the bomb would need to spread the substance to a big volume. One mechanism could be that the molecules are pressurized before they are released and that in the pressure the molecules will not react, but as released the gas spreads and then does the reaction. For that there can be made a kind of approximation of the power that the sink would "suck". Inversely you could then try to find a reaction that could produce this required effect. One thing could be that the energy for the reactions is sucked directly from the target. It would not be an explosion, but more like a gas attack. EDIT: One thing to notice is that unlike in exothermic explosion the frontier pushes itself, in endothermic the frontier would be "sucked" as soon as the reaction starts. Thus the reaction needs to be slower. The effective mechanism could be the expansion of stabilizing pressure after the sink has "sucked" energy. In exothermic the effective mechanism is the expansion at the beginning and there is then some mild suction after for the pressure to stabilize. Exothermic reactions simply are better because they can expand and they have no similar thermic limit as endothermic. [Answer] No handwavium but not possible with our current technology: convert energy into matter. This will require considerable amount of energy and will suck the heat around it. To get 1g of matter, you need $8 \times 10^{14}$ joules of energy, which is quite a lot. If I did the math right, it will reduce the temperature of 10 million tons by 190 degrees. [Answer] # **[Endothermic Explosive](https://en.wikipedia.org/wiki/Entropic_explosion)** Entropic explosives are driven by entropy rather than enthalpy. Many modern explosives are actually endothermic. However the effect is nothing like what you are expecting. In short, for the reaction to be driven by entropy, it would basically need to generate a HUGE amount of gas in a short space of time. The mechanical, concussive effect would make it almost indistingushable from an Exothermic explosive. More information can be found on the Chemistry SE <https://chemistry.stackexchange.com/questions/41979/are-non-exothermic-explosions-possible> # Cold Bomb However, what you described, is not an endothermic explosive, but rather a cold bomb. A devices that removes Entropy from its surroundings instantly. **This breaks the second law of thermodynamics.** When considering the bomb and its surrounds as a closed system. The bomb is able to reduce entropy from a closed system. This is forbidden by the second law. Any such device, must sidestep this law. Possibly by "openning up the system", using a wormhole. [Answer] Won't work. The second law of thermodynamics requires that entropy increases, and implies that to decrease entropy, you have to do work that adds more energy to the system than you took out. So, for instance, if you have two objects at room temperature, you'll need to do work, i.e., transfer energy into the system, to move heat from one to the other. That means your bomb can't be at room temperature, since to remove *Q* Joules of heat from the room, you'll need to add *W* Joules of work done, so the total energy in the system is now *Q+W* Joules, and for any combination of *Q* and *W*, the total energy of the system is greater than *Q* alone. "Bomb" implies a chemical reaction. To generate a highly endothermic reaction, you run into the same issue as above. The lowest energy state, i.e., what's left after every possible exothermic reaction possible, given the reagents present, is the most stable, just as a body at the bottom of a cliff is gravitationally more stable than at the top. In order to get your chemical mixture to move to a different combination, you'll need to supply energy, as described above. This allows you to move to a different chemical mixture that CAN potentially move to a mixture of lower energy state and WILL, unless there is an energy barrier in the way. Think of it as standing on a cliff with a high wall between you and the edge. The higher the wall, the less risk of falling off. On the flip side, if you're starting from the bottom of the cliff, the higher the wall, the more energy you need to expend initially climbing it, and the more energy that will be given back out when you climb down the other side. [](https://i.stack.imgur.com/MkcRn.png) In thermodynamic terms, you need a high initial concentration of energy to start the reaction, followed by part of it being given back. Now, bear in mind that the energy source is going to be air at room temperature. As I pointed out in the first paragraph, some 200 words ago, you can't get much energy out of a system at the same temperature, without doing work, so let's assume a fuse to start the process, give it a boost over the cliff. The fuse pushes the first few molecules into the higher energy state, and they give back some energy, a fraction of what was supplied, which can push a fraction of the number of molecules that initially reacted. So, let's say 40% reacted in the second round. In the third, 40% of the second round number will react, and so on. The reaction cannot sustain itself; more energy is needed. Bottom line, from above, the only energy absorbed, is that generated by the fuse. On the other hand, part of the energy released as the products roll down the wall, is lost to the surroundings. Net result, energy gain by the environment. TL:DR, endothermic bombs don't work, unless of course, you're using them to damp a runaway exothermic reaction. [Answer] ## Short Answer No. --- ## Long Answer There are 2 parts to your question. The *bomb* part. I am assuming this means that there is a **spontaneous reaction** with an **epicenter** and a **radially propagating explosion**. The *endothermic* part. This means that as the reaction progresses, it cools the surroundings as it passes. Let us assume that such a reaction exists, which was spontaneous (had negative Gibbs energy) and endothermic: $$ G(p,T) = U + pV - TS \\ G(p,T) = H - TS $$ This would mean that as the reaction proceeds, the reactants and products would expand (given that the assumptions surrounding the explosion). For an endothermic reaction, $\Delta H$ is positive (as the internal energy rises $U$ increases from absorbing heat and the volume, $V$, is increasing for the fluid components of the reaction - from spreading out due to the explosion) $T$ is decreasing over time. (as its an endothermic reaction) $S$ is dependent on the nature of the reaction. In order for the reaction to be spontaneous at the start (our assumption for the start of the reaction), as the reaction went along, assuming that there mechanics of the reaction stayed the same (not true - will explain why later), this would still mean that the overall Gibbs energy would tend towards a positive value over time. When it reaches 0, it stops being spontaneous and the reaction will stop being spontaneous. (it will propagate as long as it is kinetically permissible, i.e. activation constraints are satisfied) ## Why I think $S$ will decrease over time The reaction spreads radially so the reaction components themselves have to diffuse radially from the epicenter. Considering the Boltzmann (stochastic, state-based) entropy as a measure of the system, in the system of the explosion, the fluid components' internal energy only decreases. This means that the overall disorder of the system decreases - thereby decreasing the entropy. The gaseous components dominate the measurement of entropy therefore, this means that there $S$ will decrease over time. --- ## An answer but not to your question Drop a balloon filled with liquid nitrogen and it will be close to what I think you're imagining. This isn't really a 'reaction' but will have the effect of an endothermic bomb (the shockblast will be from the expanding nitrogen) and the surroundings will be cooled due to nitrogen absorbing the latent heat. --- ## How about a hypothetical endothermic self-replicating nanothermitic reaction? The principle behind a self-replicating nanothermitic reaction is that the the reaction components produce the feed stock required for the reaction to continue indefinitely from the surroundings. The absorbed energy would provide a access to the high-energy quantum states required to pass the activation energy barrier (of this hypothetical reaction pathway) and the solid products emitted would be left at such a low temperature that they supercool their surroundings as they pass through. This is just food for thought, but I guess but I don't think that the reaction conditions on Earth can sustain such a reaction. [Answer] A short response not repeating what's been said in other answers, just adding conceptual clarification: Assuming that you can indeed cause a large endothermic reaction (which wouldn't be an "explosion"), one thing to realize is that an exothermic reaction really just produces heat. Yes, light is a byproduct - when something heats it emits a range of EM radiation, including visible light if hot enough - but in the end it's all just heat. Chemicals endothermically reacting simply get cold, and therefore won't directly "absorb" light, electricity, or any other form of energy. The net result of a large endothermic reaction is that the immediate area gets colder than it was before. Still, what might rapid cooling do? Rapid contraction of some brittle solids makes them fracture/shatter (try dipping hot glass in ice water). Unprotected electronic systems will collect frost from water vapor in the air, potentially shorting them out when they thaw. Living creatures get frostbite. All in all, the effect is pretty mild if the temperature isn't sustained, and weaponizing it would be difficult without alien tech or other handwaving. [Answer] If your 'civilization' was in the ocean, or other body of water, there are several reactions that would quickly pull heat from the water, ammonium chloride, for example when mixed with water reduces the temperature of the water around it. [YouTube](https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=video&cd=1&cad=rja&uact=8&ved=0ahUKEwiVkP27rtHQAhVLylQKHQUnBioQtwIIGzAA&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DxJhjdFEHDv8&usg=AFQjCNE_UwfAZ1295ETS3VDXkhzeQ5PxsQ&sig2=bqyq4qnqRK24RsTt7PNxdQ&bvm=bv.139782543,d.cGw) Encase the ammonium chloride in a 'bomb' and detonate it in the water. ]

[Question] [ I'd like to remove the speed of light limit from my world. However I don't want to just hand-wave the consequences. How should my universe look if: * light travels at infinite speed, and so do gravity waves and magnetic fields * there is no limit to relative speed between two objects * energy cost to accelerate doesn't depend on speed Would I need to change something else to make such a world work? I am interested in consequences in outer space, space travel and observation of space, rather than consequences on microscopic scales. To **narrow** down what I'm after, I'd also like to point out that the world is a **game**, which involves people traveling between planets in their ships while obeying the rules of orbital mechanics. Therefore I need to know about: * Does anything change in the way rockets and related tech work because of my change? * **Will the background sky look different?** I assume the **same amount** of light arrives at the observer as in our universe, but suddenly we watch the universe as it **looks right now**, rather than a million years ago. [Answer] First is the speed of light is not the speed of light, ***it is the speed of causality***. [PBS Space Time has a great video about this](https://www.youtube.com/watch?v=msVuCEs8Ydo). Light goes at this speed because that's as fast as events are allowed to propagate in our universe. Make the speed of light infinite and now the speed of causality is infinite. This means events which happen here can affect distant parts of the universe instantaneously. This has serious consequences. The speed of light/causality is also a sort of universal conversion factor between mass and energy, and space and time. If it's infinite then mass, energy, space, and time are now four separate things, not two. This also has serious consequences. In our universe we have [4 dimensional "spacetime"](https://en.wikipedia.org/wiki/Spacetime). A Newtonian universe has 3 dimensional "space" and 1 dimensional "time". The speed of light is the conversion factor between space and time. If it's infinite there's no conversion. Space and time are now fundamentally different things. This has deep consequences for how our universe works, such as gravity. For example, [gravity is not a force, but it's curved 4D spacetime](https://en.wikipedia.org/wiki/Curved_space). This solved [many small discrepancies in planetary and stellar observations](https://en.wikipedia.org/wiki/Newton's_law_of_universal_gravitation#Problematic_aspects). That's easily handled by saying discrepancies simply wouldn't exist in your universe. Ok, but astronomy is really the least of the problems. Mass and energy would be different things. ***`E = mc^2`, [the mass-energy equivalence](https://en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalence), would not be.*** This has deep, deep consequences. The mass-energy equivalence doesn't say that mass can be converted into energy, it says ***mass is a property of energy***. There is no such thing as "matter", it's just a special form of energy. So much of our physical world relies on this. In a Newtonian universe matter and energy are separate things. [Here's more about the significance of `E = mc^2` from PBS Space Time](https://www.youtube.com/watch?v=Xo232kyTsO0). Since matter and energy are now non-convertible, ***both energy and matter would always be conserved***. Fusion, which converts part of the rest mass into energy, would not be possible. ***No fusion, no heat from stars. No heat from stars, no life.*** Stars just collapse under gravity into lumps of matter initially heated by gravitational collapse but eventually going cold. Neutron stars (and regular stars) require quantum effects which don't exist in a Newtonian universe. In a relativistic universe, because of the mass-energy equivalence, energy has "mass". A box containing 1 gram of matter and one containing [9x1013 J](http://www.wolframalpha.com/input/?i=mass+energy+of+1+gram) of energy have the same mass-energy and the same gravitational pull. In a Newtonian universe this is not so. There is no mass-energy equivalence so energy does not exert nor feel gravity. No gravitational lensing. No black holes. Energy can only be absorbed and reflected. The speed of light shows up in many equations, even those they appear not to. Many of the physical equations we learn in school are actually non-relativistic versions only for use at low relative velocities. For example, the kinetic energy equation: `1/2 m * v^2` is [far more complicated in relativity and uses the speed of light](https://en.wikipedia.org/wiki/Kinetic_energy#Relativistic_kinetic_energy_of_rigid_bodies). Making the speed of light infinite changes all this. Then there's the question of time. If light, energy, and causality travel at infinite speeds, we have no "past" and no "future". Everything happens in the "present" all at once. ***If the speed of light/causality is infinite, we have no time.*** Again, [here's PBS Space Time on the origin of time and why speed of light is necessary for time to exist.](https://www.youtube.com/watch?v=fHRqibyNMpw) --- There you have it. ***No space-time. No mass-energy equivalence. No fusion. No stars. No time.*** A Newtonian universe would be very, very, very different. That's just the broad overview. Many, many everyday equations change, or must be derived in a radically different way. I also didn't get into the lack of quantum mechanics which eliminates everything from transistors to stars (again). [There's more about that on Physics.SE](https://physics.stackexchange.com/questions/152920/how-would-night-sky-look-like-if-the-speed-of-light-was-infinite). For your universe to work and be consistent ***you'd have to re-engineer a significant portion of reality so the macroscopic world still works as it does now***. Alternatively ***you leave your world at the 18th century level of understanding***. Stars shine, there is time and causality, they don't know how or why, and you don't need to explain it. ***[The linear relationship between velocity and kinetic energy](https://worldbuilding.stackexchange.com/a/38792/760) allows spaceships with far simpler technology.*** Or you just don't let anyone with a decent physics background play. :) [Answer] Given that we are not sure of exactly how big our universe really is, because of the speed of light only allows us to observe so far, it could be that the night sky would be blindingly bright, with the light of stars in every direction extending off into infinity. Essentially we're looking at a universe without relativistic effects. No time-travel. However, if the mass of an object did not increase with it's speed, then we could have some interesting theories about space travel, but nothing within the reach of our technology in the next hundred years or so. Also, because light travels anywhere instantly, we can communicate across any distance with no latency, so the internet would be happy :) [Answer] The biggest difference is that all of chemistry would depend on your current velocity. In Newtonian mechanics, you have what is called a "Gallilean transformation". This describes how to change reference frames. For example, if I am standing in an airplane, I can toss a football to you easily, even though we are both moving at a very fast speed. I don't need to consider the speed of the airplane, determine where you are, then aim the football at where you will be in 2 seconds. I just pretend that the airplane is motionless and throw the ball to you. This works because the Laws of Motion do not change when applying a Gallilean transformation. In a non-Newtonian universe, such as the one we live in, the Gallilean transformation is not perfectly accurate. When you get close to the speed of light, you need a "Lorentz transformation". This has the same concept, making the airplane look at though it is stationary, but works with special relativity. Now we get to Maxwell's Equations. These describe electricity and magnetism. Now, unlike the Laws of Motion, these change under a Gallilean transformation, but not under a Lorentz transformation. In our world, an electric motor performs identically regardless of whether it is stationary or moving very fast on an airplane, because our universe uses the Lorentz transformation. In a Newtonian universe, using the Gallilean transformation, electricity would work differently in the two cases. Now, what effects would that have? Well, change the relative strengths of electricity and magnetism, and the atom changes size. The fine structure constant also would change, so all of your elements would start having different chemical properties. * A factory in which some critical step occurs at high velocity, where a chemical reaction can occur that wouldn't otherwise happen. * A speed limit of safe travel in outer space. You could continually accelerate, but eventually you would reach a velocity at which the chemical processes in your body no longer function. * The military would develop supplements that would allow their ships to travel at a faster speed, by replacing the proteins that your body can no longer produce. * An alien civilization, traveling through the same space as us, but at a different velocity, might be based on their different chemistry. Trade would therefore be very difficult, if not impossible. * Planets closer to their star, having a wide range of absolute velocities throughout their orbit, would be much less hospitable. Life there would need to survive at a wide range of possible chemistries. [Answer] If your universe is bounded but the speed of light is infinite, then you have to worry about what happens when light hits the edge, which of course it does instantly. And what does that do to conservation of energy? If it's not bounded, then you have to worry about Olbers' Paradox. Astronomy and cosmology will be greatly handicapped by the inability to see into the distant past and by the lack of red shift (I assume there will be no red shift, since the formula for red shift depends on the ratio of the speed of recession to the speed of light). [Answer] Trying to come at this from a different angle than all the awesome physics based ones and focus on a couple of points from the game aspect: A) Assuming we hold to your "ignore the microscopic implications" (meaning things like computers and related are a thing), I think scanners are a bit more realistic in your universe than a lot of other video game universes (in the sense that a probe near Earth would be able to detect a big ship near Jupiter in real time versus an multiminute delay that generally doesn't show up in most video games) although I'd be willing to be corrected; my assumption for having a scanner in solar system being able to detect stuff in an adjacent solar system would still be unlikely due to the power of the signal falling off with square of the distance (although I could see some interesting things with mirrors if light travels infinitely fast) B) Likewise, Laser-based weapons would seem to be even more desirable (and force shields to be even more critical). If light has a finite speed and aliens in a galaxy 10 lightyears away want to declare war by launching a massive laser blast, it still takes 10 years for that to happen which is rather uninteresting for most games; if the speed of light is infinite, then I would expect if shields aren't always on, war devolves into galaxy wide MAD... although again I'd be willing to admit I don't know if even a perfectly coherent laser doesn't lose potency over that distance. C) Rocket-wise, for manned rockets I wouldn't think a lot changes (again assuming we ignore the micro-effects); you're still going to want to limit the G forces human pilots/passengers endure. For unmanned drones, you again can build a super weapon by taking a big hunk of rock, boosting it arbritarily fast at the enemy planet, and even if the scanner system could detect it, given that there would still be some sort of reaction delay, unless the enemy planet has always on deflectors, I would expect they'd be having a bad day. [Answer] At low speeds (low including the velocity that stars and planets moving with relation to each other) you will see basically no changes. Newton's laws are a good enough match that it took a long time before we needed relativity. The main difference to the larger universe is that there will be no such thing as black holes, it is always going to be possible (although it may be very difficult) to escape. Rockets and suchlike will work just as they do now, we've never tried to accelerate anything to the point where relativity starts to be a problem. Constellations would look different as they would reflect current positions in the sky but that's only going to matter to people looking in detail. You should also consider the effect of gravity on light, for example will you still have gravitational lensing? If you have it then a black hole could still look like this: [](https://i.stack.imgur.com/jujaG.jpg) ([The fictional black hole "Gargantua" from the movie Interstellar produced in association with physicist Kip Thorne](http://www.space.com/28552-interstellar-movie-black-holes-study.html)) But you would need to think about how gravity can bend something moving at infinite speed. [Answer] If you try to just look at what happens to Maxwell's laws of electromagnetism in the limit as the speed of light approaches infinity, one problem is that in Maxwell's theory all electromagnetic waves are produced by accelerating charges, but if you look at the [Larmor formula](http://en.wikipedia.org/wiki/Larmor_formula) which is derived from Maxwell's laws, as c approaches the infinity the power radiated by an accelerating charge should approach zero, so there should be no measurable electromagnetic waves at all in this universe. An alternative you might want to consider would be to use something like the old [luminiferous aether theory](http://en.wikipedia.org/wiki/Luminiferous_aether) that physicists tended to assume prior to the [Michelson-Morley experiment](http://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment) which produced results inconsistent with it. In this theory, it's assumed that electromagnetic waves are a type of sound wave in a medium pervading space, the luminiferous aether. It's assumed that Maxwell's laws only hold exactly in the rest frame of the aether, in other frames would have to be modified by a [Galilean coordinate transformation](http://en.wikipedia.org/wiki/Galilean_transformation). For example, just as it's true that all sound waves in air travel at the same speed in the rest frame of the air, but not as measured in the frame of an observer moving relative to the air, the same would be true for the aether: an observer moving at speed v relative to the aether would measure light waves to travel at speed v+c in one direction and v-c in the opposite direction. One assumption here is that it's possible to create some sort of physical ruler which isn't observed to undergo [length contraction](http://en.wikipedia.org/wiki/Length_contraction) when it's moving relative to the observer, and clocks which aren't observed to undergo [time dilation](http://www.phy.olemiss.edu/HEP/QuarkNet/time.html) when moving relative to the observer. Perhaps this would entail that they are held together by non-electromagnetic forces; the microscopic structure of matter would have to change in a non-relativistic world. But note that there is a [non-relativistic quantum model of atomic structure](http://en.wikipedia.org/wiki/Hydrogen-like_atom#Schr.C3.B6dinger_solution) based on the Schrodinger equation which is [invariant under the Newtonian coordinate transformation](https://physics.stackexchange.com/questions/56024/galilean-invariance-of-the-schrodinger-equation) (which does imply that rulers and clocks whose structure was determined by these laws would undergo no length contraction or time dilation), so you could assume that if you only want your universe to be "Newtonian" at macro scales but allow it to be quantum at micro scales. Though I don't know of any non-relativistic version of nuclear physics, so that would imply that stars radiate just due to some combination of chemical reactions and thermal radiation (assuming they form in a hot state), in which case they would cool down more quickly--the physicist William Thompson (or 'Lord Kelvin') [once calculated](http://zapatopi.net/kelvin/papers/on_the_age_of_the_suns_heat.html) an upper bound of about 20 million years of heat for a non-nuclear Sun. If you assume your universe is infinitely old as in the [steady-state theory](http://en.wikipedia.org/wiki/Steady_State_theory), rather than the current state having resulted from the expansion of space since the Big Bang as in the cosmology of general relativity, you are also going to have a problem with [Olber's paradox](http://web.williams.edu/Astronomy/Course-Pages/419T/olbers.pdf), which says that in a universe with infinite stars distributed throughout space and radiation obeying an inverse-square law, one would expect the entire night sky to be lit up no matter what direction one looked. Since the steady state allows new matter to be created, perhaps you could just assume the universe was empty and then the matter-creating process "booted up" some finite number of years ago, then if you combine that with the idea that light travels at a finite speed as in aether theories, that would explain the mostly-dark sky. As for gravity, it could just follow the [Newtonian formula](http://theory.uwinnipeg.ca/physics/circ/node7.html), whose results are a bit simpler to calculate than with relativity (note that if you combine with an aether theory for electromagnetism, electromagnetic waves would not be affected by gravity, unlike in relativity, so there'd be no black holes or [gravitational lensing](http://www.cfhtlens.org/public/what-gravitational-lensing)). And macro objects in such a universe would obey [Newtonian kinematics](http://www.physicsclassroom.com/class/1DKin/Lesson-6/Kinematic-Equations) and the [Newtonian laws of collisions](http://www.animations.physics.unsw.edu.au/jw/momentum.html), even if they obeyed non-relativistic QM at a micro level, due to the [correspondence principle](http://en.wikipedia.org/wiki/Correspondence_principle). This implies that if you have a rocket using up a constant amount of potential energy per unit time to fling exhaust backwards at a constant rate, its velocity will also change at a constant rate as seen in the frame of any given inertial observer (constant acceleration in their frame). So, in this sense it would be true as you said that "energy cost to accelerate doesn't depend on speed" (at least if you are looking at the energy cost for observers on board the accelerating object, as measured in their instantaneous inertial rest frame at any given moment), and also that "there is no limit to relative speed between two objects" since velocity in the observer's frame can get arbitrarily large as long as the rocket has enough fuel (so, a rocket could overtake light waves in much the same way an aircraft can break the sound barrier--this would presumably lead to a sort of electromagnetic "boom" similar to [Cherenkov radiation](http://en.wikipedia.org/wiki/Cherenkov_radiation)). This is in contrast to relativity, where although an observer on board the rocket would measure a constant [proper acceleration](http://en.wikipedia.org/wiki/Proper_acceleration), the coordinate acceleration measured by an inertial observer would continually decrease as the rocket approached a speed of c in the observer's frame. [Answer] If gravity also travels at infinite speed, then we would *probably* have a [Big Crunch](https://en.wikipedia.org/wiki/Big_Crunch) due for the universe. Also, [solar sails](https://en.wikipedia.org/wiki/Solar_sail) would be much more efficient in that universe for space travell. I have no idea if the mysteries of [dark matter](https://en.wikipedia.org/wiki/Dark_matter) and [dark energy](https://en.wikipedia.org/wiki/Dark_energy) would still exist in the universe. In general, newtonian physics is **much** simpler than modern physics. If intelligent life does exist on other planets, we probably would already have had made contact with them, considering that communication speed would be infinite. Although the night sky would be much brighter than it is today, I don't think it would be *blindingly* bright. Light disperses a lot with distance, but then again, all of the universe would be in instantly observable range. I *think* starlight alone would be as bright as twice the full moon. Last but not least, I would not be posting this answer here, as Andromeda would already have had collided with Milky Way since a long time ago ... [Answer] The really big implication of this would be losing randomness in such universe. Everything would be perfectly predicable, down to the subatomic level. (Assuming by Newtonian universe you also mean quantum mechanics do not exist.) There would be no transistors and all computers would be based on some other sort of method to compute numbers (whether digital or analogue). If people in such universe would be able to build a supercomputer that can approximate the universe, they would find out that they lack free will and consciousness, since everything will be predictable and everything in the past would be known, just by running a simulation. See <https://en.wikipedia.org/wiki/Uncertainty_principle> and <https://en.wikipedia.org/wiki/No-cloning_theorem> both principles are fundamental to how our universe work. Basically it is very hard to say if everything would change, as you removed a huge chunk of the physics in our universe. We can only hypothesize, and we can't even know if such universe would exist or stay stable. [Answer] If the speed of light is infinite then there's no relationship between frequency and wavelength of electromagnetic energy, e.g., radio waves. So radios and antennas and related technology (wifi, radar, microwaves, etc, etc, etc) either don't work at all or work (and look!) really differently than they do in our universe. Light would also be very different but I haven't taken the time to figure out how. ]

[Question] [ So, I have built a Time-Traveling machine. It’s a prototype, and I’ve noticed a few kinks in the machine. If the control pad gets jammed in home mode, the universe will repeat the same day for all eternity. Also, I noticed that my machine can only go back in time within a limited range. I can go anywhere in time between ***August 12th, 1941*** and the present. This is very important to the plot of my story, and I want to give a logical reason why it is that way. My question is, what is a plausible reason why my time machine is limited like this? [Answer] There's an old fashioned option ### You can't travel back in time to a point before the invention of the first time machine. That means of course that the first person to invent a time machine couldn't travel back in time to point before his own invention, and possibly initially thought it didn't work, which is true for a given value of true. [Answer] A previous time machine crashed and exploded on August 12th 1941 during a test flight. Maybe sabotage or a design fault. The explosion and shockwave will exist forever at that point in time. The explosion acts like a reverse black hole. The closer you get to the point of time of the explosion, the more power you need to bypass the shockwave emanating from it. The power required to bypass it increases exponentially and generating that amount of power is impossible with your current technology. [Answer] You need to know where the Earth is. If you think about it, the Earth is spinning around the sun, in a spinning galaxy in an expanding universe. If you just headed back in time, you'd appear in the void of space. Not only do you need to know when to send someone, you also need to know where. To have a limit on how far you can go back, your time machine has only calculated where the Earth is to that point. If you try to go back further, you'd end up floating in space. [Answer] If you're willing to accept that the machine (as in this *specific* apparatus for time travel; not as in *any* apparatus capable of time travel in your universe) cannot travel further back in time than some specific amount of time, rather than to some arbitrarily selected date, then there's an easy option that might even make a modicum of sense scientifically (to the point that anything about time travel can be said to make sense scientifically in the first place). Make it so that **time travel requires power. Tons, and tons, and *tons* of power.** Not just [energy](https://en.wikipedia.org/wiki/Energy), which you can store (think batteries), but pure, unadultered, raw [*power*](https://en.wikipedia.org/wiki/Power_(physics)), which is the instantaneous *flow* of energy. (Energy is measured in watt-hours or multiples thereof; power is measured in watts or multiples thereof.) The farther (back or forward) in time you go, the more power it requires. So a ten day time jump requires more power than a five day time jump. The relationship between the two could easily be anything from sublinear to a [tetration](https://en.wikipedia.org/wiki/Tetration), depending on how time travel works in your universe. Something about the design of the machine causes it to not be able to handle arbitrarily large amounts of power. There is nothing strange about this part; not even a simple electrical wire can handle an arbitrarily large amount of power. There might also be some design or physical reason why components need to be *below* a certain size to work correctly, so you can't just make them bigger in order to handle more power; if you try, they fail to work for this other reason. Modern computer CPUs fall into this category; if the die was much larger, then the speed of light propagation delay in terms of clock periods becomes prohibitively large, thus putting an upper limit on how fast a given CPU design can be clocked. (Note that the physical chip is much larger than the die.) **It just so happens that this power limit works out such that on the first day that the machine works, it can't travel back in time further than to your chosen date.** If you were to try, it'd burn out a critical component, resulting in anything from just a stranded protagonist with a spare part to complete destruction of the machine and anything near it. (Your choice of value for "near".) Obviously in that case, the next day, the machine will only be able to travel back in time to the day after your chosen date, because the target time window moves as time goes on. To keep the protagonist from making multiple smaller time jumps instead of a single large one, limit the machine's carrying capacity and the energy density of whatever devices power it. Maybe in your universe, there's a hard upper limit to the amount of mass that can be transported to a different time; much like how in our universe, there's a hard upper limit on speed (that is, the fact that nothing can exceed the speed of light, and that nothing with a non-zero rest mass can attain the speed of light). [Answer] The simplest way would be to limit the machine's range (see Asimov's classic *Chronoscope*). But this way you wouldn't have a "precise start date", as the start date would move forward in time. You could have some strange mechanism by which the range extends gradually backwards - each day, you can reach exactly one day farther in the past. So the farthest date remains the same. Otherwise, you need some key event that never occurred before, or never occurred in a reachable range before (i.e. if you have a range limit of 5,000 years, it's enough that it only occurred the once in the last 5,000 years - the 7129 BCE event isn't reachable anyway). So we need a plausible unique event to have happened no earlier than August 12th, 1941, and a reason why it's crucial. The time machine requires orienting in 4-D spacetime, which can be accomplished only by either specially constructed beacons or by exploiting point-like natural phenomena whose location in spacetime must be known with great precision. Once the beacon is locked on, any spatial coordinate within a reasonable range in the same timeframe can be reached. Interpolating two beacons allows reaching any timeframe between the two. The earliest known such phenomenon, Beacon Prime, was a self-contained, unreported small-scale criticality accident inside a six ton uranium oxide pile located in New York, on the 7th floor of University of Columbia's Pupin Hall laboratory, in the morning of August 12th, 1941. Something very similar appears in Dave Freer's *Pyramid Scheme*, where an alien probe targets the [exact point where the first large-scale nuclear fission reaction took place](https://en.wikipedia.org/wiki/Chicago_Pile-1), in Chicago, on December 2nd, 1942 (where the New York pile had been transferred since 1941). > > It is a choice designed to give Earthmen the idea of hitting the Krim probe with nuclear energy, thus giving it enough energy to engulf the whole Earth. > The evil Krim's plan backfires spectacularly. > > > [Answer] The time machine comes with a lifetime warranty, but with a twist. It is warranted for the lifetime of its inventor. The inventor wanted to make sure that the grandfather paradox would not apply to himself. So he put lockouts in the control system, to prevent any attempt to jump to before the inventor's birth. Perhaps the software lockout is reinforced by a hardware lockout, such as this: * The control system includes quantum entangled qbits. * Some of the qbits are part of a positronic brain. * Their twin qbits are part of a regular electronic brain. * The inventor sought out quantum entangled qbits that use positron-electron pairs that were made on his birthdate in a MeV (Mega Electron Volt) particle accelerator. (Somehow somebody stored and kept track of these particle accelerator products.) * If you go back to before the inventor's birthdate, each pair of critical qbits is replaced by a 1 MeV photon. As [Michael Kjörling♦](https://worldbuilding.stackexchange.com/users/29) points out, the time machine needs a lot of power. In particular, it needs a lot of power to open the doors. This power is obtained via a controlled matter-antimatter reaction. An electronic brain controls the matter side of this reaction; the positronic brain controls the antimatter side. The two are linked via the quantum entangled qbits. If you go back too far, the link between the two brains dissolves, and you cannot open the door. At the story author's option, if you then return to the valid operating range of the time machine, the link is reinstantiated, and you can open the door. The positronic brain is not a user-serviceable part. If the user tries to physically tamper with it, the antimatter is likely to be catastrophically released. As a bonus (for the inventor), the warranty terms give customers an incentive to extend (rather than reduce) the inventor's lifespan. [Answer] You did not build a time machine, you built something that force loads the save state of the simulated world you are trapped in, which is a mirror of the world on August 12th, 1941. The illusion of time travel is maintained by the "time machine" inserting you into the world after the simulation has run for a specified amount of time. Or perhaps time travel cannot actually violate causality. A time machine cannot actually travel back in time, it is instead a beacon that summons things from the future. Your "time machine" is just one of many possible objects and phenomena that can interact with this beacon, which was created on August 12th, 1941. [Answer] If your time machine can only travel into the past. Presumably it must create an effective "anchor" for its initial launch point. That is, the present. Therefore, if the time machine can access any moment in time between the anchor point time and 12 August 1941, its range of travel is from now, backwards in time, to 12 August 1941. And with all stops in-between. This is a time machine with a range of seventy-seven (77) years backwards in time. The time machine is also capable of travelling to any time within that range. It is left as an exercise to the querent (or OP, if you prefer) to calibrate the exact limits of its backwards range. EDIT: There is another possibility suggested by @RonJohn's comment, but related to the rationale presented above, namely, that the time machine created a fixed "anchor" point in the past at 12 August 1941. There is an effective range for its setting a past "anchor" point, but once set this will be the limit of travel into the past and any points in-between the present and 12 August 1941. In this case, the past limit will remain 12 August 1941, but the upper temporal limit will always be the present. Any time machine on start-up will create its past temporal "anchor" point seventy-seven (77) years in the past, but its upper temporal limit will continue to stretch forward in time. [Answer] A lot of nuclear research was happening at that time. Some event in that context weakened the fabric of spacetime enough for time travel to work. Before that event, spacetime is just woven too tightly to wade through in any feasible time machine. So research some event that either happened on that day or can be plausibly argued to have happened on that day and been misrecorded in History. Or make up an event that was lost to history, due to intense secrecy and other causes. Optionally, this could be unknown to everyone, and possibly discovered as a plot point. (If you could push your limit date to 1945, the [first detonation of a nuclear weapon](https://en.wikipedia.org/wiki/Trinity_%28nuclear_test%29) would fit the bill perfectly) [Answer] > > On 9 October 1941, President Roosevelt approved the atomic program after he convened a meeting with Vannevar Bush and Vice President Henry A. Wallace. > > > <https://en.m.wikipedia.org/wiki/Manhattan_Project> A few weeks before that some kind of experiment happened that’s crucial to time travel. Maybe it depends on an isotope that came out of that lab. Maybe it acts as some kind of beacon. (And since then new beacons were created at an increasing rate, to the point that travel to any precise moment from mid 1940s is possible.) [Answer] **Epoch Time** The Time Machine is built and runs using a variation of Linux and the epoch date - 0 date - is set to August 12th, 1941. Normal Linux machines of a "0" date-time of January 1st, 1970... but for some reason, the Time Machine has a different "starting" datetime set as epoch. Trying to use a date before "0" in the operating system causes a system crash. <https://en.wikipedia.org/wiki/Year_2038_problem> I'll wager the version of Linux uses an unsigned integer though... using a signed integer would make the limit of the machine 68 years (1941 to 2009)... making it unsigned would stretch that 32bit field to 138 years (1941 to 2079). That would mean any attempts to go before Zero... or after 2079 (Whatever the exact math boils down too) would either crash (going backwards) or overwrap (going forwards). Sure, you might be able to recompile the Operating System or port the Code that runs the Time Machine... but, sadly, the original programmer isn't with us anymore (How do you think we learned about the issues with the code? Woops). So the effort to rebuild and rewrite are prohibitively expensive - and getting more so. Ever try to hire a Cobol programmer? same issue, times 1000... **Variation on the theme** The epoch time is set for 2009 with a signed integer. So, the furthest back you can go - before over-wrapping integers occur - is 68 years: 1940. And the furthest forward you can go is 68 years: 2079. [Answer] **Time is weaker in mid-to-late 1900s due to frequent time travel** Your time machine is presumably the first time machine ever invented and is considerably weaker than other time machines that will undoubtedly be invented in the future. As such, it cannot fully "punch holes" in the fabric of spacetime to jump to any arbitrary point. It only works on regions of history that have already been "worn down" by more powerful future time machines. As it happens, the buildup towards the atomic era / World War II and the aftermath thereof is by far the most well-studied part of (currently past) history and is therefore "weak" enough for low-powered prototype time machines to travel to. August 12th 1941, while not important in and of itself, happens to be the limit of how far back you can go with your current technology and power source due to wear and tear from travelers to subsequent months and years. (There is a slight blurring; travelling to time X also weakens down a surrounding area of history inversely proportional to temporal distance.) [Answer] Your main character bought an entry level time machine. August 12, 1941 is its earliest setting. Travel to an earlier point in time requires either a different, better, time machine, or an expensive upgrade (and the time machine will be in the shop for six weeks to be able to perform that upgrade). [Answer] ### It's a result of the computer's programming. In many modern computers (Linux, macOS, iOS, Android, basically everything except Windows), computers keep track of the time by counting the number of seconds since January 1, 1970 (because this scheme was created in the early 70's). This is called [Unix time](https://en.wikipedia.org/wiki/Unix_time). Somewhere in your time machine's code, the time is limited to [-895,852,800](http://m.wolframalpha.com/input/?i=August%2012%2C%201941%20in%20Unix%20time). Maybe that was the programmer's phone number. Maybe they were lottery-winning numbers. Most realistically, if you're flexible with the date, they rounded it off to -900,000,000 ([June 25, 1941](http://m.wolframalpha.com/input/?i=-900000000%20Unix%20time)). (Unfortunately, there's no powers of 2 that are sufficiently close.) [Answer] Summarizing from the H2G2 > > Long ago, the people of Krikkit attempted to wipe out all life in the Universe, but they were stopped and imprisoned on their home planet; > > > August 12th, 1941 is the day [Bobby Peel](https://en.wikipedia.org/wiki/Bobby_Peel), a cricketer, died. > > he became well known for liking alcohol > > > Actually, he didn't really died, he simply hitchhiked to a different dimension to keep hold of the people of Krikkit. Traveling back in time to before that day will trigger the people of Krikkit into unleashing their evil plan. The Universe itself conjure to protect life, and tweak its own laws preventing time travel earlier than that date. [Answer] The August 12th 1941 limitation is one of range. Not temporal range, the machine can theoretically go anytime you need it to go. No, the problem is in the other three dimensions. The time machine in question has two separate engines: One for translating the equipment in the fourth dimension, which due to properties of time travel itself, can go basically anywhen. The other is a 3D transversal device that ensures that when the machine moves in the 4th dimension, it ends up in roughly the same 'place'. Unfortunately, this 3D transversal device has to struggle against galactic inertia to make sure that when we travel we don't end up in the empty space between solar systems after making a small hop back to 1972. It's remarkably efficient at this, but is limited by the antimatter fuel tank that powers the device. So we've built in a safety (margin ~10%) into the travel so we cannot accidentally get stranded in interstellar space. The big advantage is that we don't need to find antimatter in the past, as we can piggyback on the existing velocity to ensure we end up in the same place when traveling forward. As for your home screen jam, are you sure you didn't accidentally engage the timer function? The timer function is a safety feature to make sure the device isn't captured by hostile forces in the past, it lets you either make the machine make jumps of a specific time (so every friday, at 10PM, you can find the machine in the same place). If you set the loop to a day in the past and are wearing your temporal anchor (you are wearing your temporal achor, aren't you?), it would certainly look like a groundhog day type scenario. Good news though, it won't repeat the same day forever, just until the antimatter fuel talk that powers the 3D transversal device runs out, which should be somewhere in a hundred years or so. [Answer] **Limited Temporal Scouting** Before you acquired the time machine, someone had to map space-time coordinates to feed into it, this took a lot of trial and error and a lot of ending up in deep-space before they got a short list of viable data out of it. Getting new data is really *really* hard. Or at least takes very specialised equipment that you don't have. The onboard computer can also interpolate the data it has to produce a sliding range of viable coordinates so that you can essentially pick any date within its range. However if you want a wider range, someone is going to have to map earlier or later coordinates. As it happens, the earliest date you have access to is august 12th 1941. Explanation B: The initial jumps for the machine were disasters, the machine consistently wound up in deep space and after much spinning of dials and random coordinates you found just one viable space-time coordinate that worked. August 12th, 1941. By interpolating your starting space-time coordinates and the viable one, you managed to get a range of coordinates that you can travel safely within, but if you want more then you'll have to deal with the random-number-generators again. Home mode is very simple, the machine's guidance systems detect what day it is (by the 24 hour period). And if you jam the guidance systems into going home, then at midnight that night, the machine detects it's no longer on the correct day and jumps back in time 24 hours automatically to compensate. [Answer] There is an obvious possibility. The clue can be found here in this part of the question. > > If the control pad gets jammed in home mode, the universe will repeat > the same day for all eternity. Also, I noticed that my machine can > only go back in time within a limited range. > > > Like many prototype machines, the time machine has a fault or most likely several faults. If the control pad is jammed in home mode, the machine is stuck in a time loop. Therefore, part of the time machine's circuitry or whatever kind of mechanism is either to control or propel the time machine has gotten itself stuck on 12 August 1941. While the machine can travel between then and the present. (It is only backward and then forwards again type of time machine.) The good thing is this can be fixed. Take the largest spanner you can find and strike the side of the time machine several times with great force. This should unjam its mechanism and the past before 12 August 1941 should become accessible. Either that or it's back to the workshop to fix the fault. Levity aside, a plausible explanation for the limited time travel could simply be a technical fault. [Answer] While booting your machine for the first time, you thought you've need to enter your birthday, while it was the limit time range, here for security purpose. [Answer] Lots of great answers already, but one possibility not yet even implied: Your time machine "finds" the correct spot on Earth and in time by triangulating multiple stars and solar system bodies. Unfortunately the astronomical reference library you downloaded includes a star which had a dramatic phase change whose light reached the Earth in 1941; earlier than that date your geotemporal library fails to resolve. (In 17 years when time travel becomes widespread you will open-source your control software and a 14-year-old from Nigeria will find and fix the bug.) Alternate bug: there was a leap second you left out of your time math routines. [Answer] The solution I'm offering doesn't limit to a specific date but rather to a specific range. It also allows travel beyond that limit, which will be either extremely inconvenient or unsafe, or likely both. This was inspired by real life, turns out whether you should use float, double or decimal sometimes matter a whole lot. --- **Time is much like space: better explored when you know where you're going**. Anybody who've seen Stargate knows you need two things to travel: the coordinates of the destination, and the coordinates of the point of origin. Well, consider it's called space-time continuum for a reason, any point in time is therefore identified by coordinates. To find your way between now and then, you need to calculate a trajectory through time. Double the fun if time travel implies defining the location in time *and* space. **The basic conundrum is you can either do things fast or precise**. You can travel between any two points with tip-top accuracy by using arbitrary-precision arithmetics (aka as infinite-precision, which sounds way cooler), a supercomputer and three years of your time. Note that you'll have to predict how long the calculation takes, and input the precise time of your departure in advance and stick to it with rigorous precision. If the calculation fails (computer crash or other calamity), you'll have lost all that time for nothing. And then you'll have to do it again to calculate your way back in advance, since it's unlikely you'll find a supercomputer in the 1940s. If anything goes wrong, if you meet an unexpected obstacle, and if you miss your mark going back or forth, there is zero guarantee you'll be anywhere near where/when you want. All in all, you can dismiss that possibility by denying access to the appropriate resources, supercomputer time ain't cheap, nor is the power plant to get the lights on, or by making your characters sane enough to not consider doing it that way. So instead you'll aim for something fast using built-in floating-point arithmetics. It will take a couple of minutes at most but the trade off is accuracy. There is a range of time where you're 95% certain that you will be where and when you want, give or take a day or two. Beyond that, the machine might send you to the Moon *and* miss the date by a century. Essentially, the further you go, the worst your odds are. As a good software dev, you've put blocks that limits use to a defined safe range. It just happens 1941 is the limit if you were to start travelling from today. --- Obviously, that opens the door for someone to travel by increments. If you have a 10 year range and want to travel 100 years back, you'll just do it in 10 steps. Well, to close that door, the machine can have an autonomous power supply that is good for two travel and a half, one in, one back and some reserve for rainy days, and then you are stuck in time forever. Also allows you to sacrifice your time machine to do something really important. You might also have an unsafe mode hidden and accessed by typing Ctrl+Shift+C and enter rosebud, but it's called unsafe for a reason. It might just transform you into a fly instead of doing what you ask. So again, you would not consider doing that unless you had really important and dramatic reasons for it. [Answer] The time machine abuses the effects of a wormhole linking any point in time along the circumference of the wormhole to any point on the other end of the wormhole. But any point of time that isn't somewhere along this circumference cannot be reached via the machine. This would work both ways. You have an earliest date you can reach and a latest date that you can reach. But this is less of a problem since you can go some place in time that's close and just wait for time to pass normally. You can't exactly wait for time to go backwards [Answer] You are not the first inventor of a time machine. In an ironic twist a *future* inventor created the first time machine and traveled back to August 12th, 1941 and became trapped. He brought with him future technology, or at least knowledge and took advantage of it to survive. Your time machine is dependent on inventions and discoveries made possible by this future time traveler bringing back this future information. [Answer] There's a biological resonance effect. Your protagonist can only go back to periods where they as a person existed (ie. anytime after you were born, August 12th 1941) Yes, this makes them about 77 by the time of the story, but if you can do time travel in any fashion, biological aging might be simple by comparison. [Answer] **In the eternam words of Mr. Spock, "Nature abhors a vacuum"** And *nothing* creates a vacuum like moving something or someone away from when they're supposed to be. The further away you move in time, the stronger the "time vacuum" gets. The curve is exponential over time, and it hits its practical "infinite force against the vacuum" point at time X from the origin. Further, you could say the more critical the need for the person to be at his or her appointed time, the stronger the vacuum created when they leave their appointed time. After all, time is trying to contine back when they were, but now it's being *held back* by the lack of one of its parts. And if your baby's being born and you were expected to be by your wife... oooohhh... nature really hates that kind of vacuum. *The value of this solution is that you could easily create some pseudo-math to support it.* [Answer] It's due to the operating system of the machine. When working with bits and bytes, dates and times are stored as an amount of milisseconds from a base date. For many programming languages, the base date is somewhere in the 20th century. You can have a negative amount of miliseconds to represent earlier dates, but due to integer size constraints, you can't go too far into the past (nor into the future as well). In Javascript, dates use 64 bits and can go all the way back to 285,616 years before its base date (January 1, 1970). Perhaps you designed your time machine with a base date around like your present and a date type that is only 11 bits long - that will allow you to go back or forward in time 84 years from your base date. Better yet... Your base date IS the fiethest you can go into the past. Due to a one character typo in the source code, your machine does not tale negative values. You can go anywhen in the future, but you can't go anywhen before the base date. Add to that you lost the source code and the compiled executable you have is too complex to reverde engineer. [Answer] You could use this [event:](https://en.wikipedia.org/wiki/August_1941#August_12,_1941_(Tuesday)) > > The Royal Air Force conducted the heaviest daylight bombing raid against Germany since the war began. The Germans could not offer as much opposition as they once did because many of their planes had been diverted to the Eastern Front. > > > The royal air force had used a wormhole, that day in order to attack; the wormhole is still open to this day through space and time and it is the only way the time machine can travel. Beware! In order to be consistent, your time machine should stop working if the wormhole somehow stops working, or being cut. [Answer] While the Royal Air Force Bombing Raid on Germany, they hit a Special Nazi Project on Researching of the possibilities of Time Machines. Accidentally one Specific Particle was released that blocks every interference with Time before that Particle was release. Like a Barriere in the Time. Another Possibility would be that on that event, a Particle was created (due to the bombing) that make it possible to travel in Time. So it isn't possible to travel before that Particle was create because of the Grandfather-Paradox (change the Time so that the Particle was never created so timetravel was never possible ) [https://en.wikipedia.org/wiki/August\_1941#August\_12,*1941*(Tuesday)](https://en.wikipedia.org/wiki/August_1941#August_12,_1941_(Tuesday)) [Answer] @Separatrix Basically summed it up but there, but one theory holds that the time machine doesn't travel through time like a car travels through space, but rather like an elevator travels through an ever increasing building. Imagine if you will that time is a perpetually growing tower... a new story is added at the rate of one second. There are no stairs or entrances to another level other than the one you are presently on. If an elevator was created on August 13, 1941 at exactly midnight local time, than that elevator shaft will continue to receive an addition every second of an extra floor... But it cannot create floors retroactively.... So from our present time, we could take the elevator all the way back to the date that it exists and all the way forward to the date that it ceased to exist... but we could never go beyond those limits... there is no floor to go to. The time-elevator would also be spacially locked... it can only exist in one place while turned on and cannot be moved... thus if you built this in... lets say area 51 because we always build the really kooky machines there... than you could travel to the past, but it would be area 51 in the past (Think 4th dimensionally, Marty!). [Answer] The first atomic test wasn't in 1945, but clandestinely, on August 12, 1941. Your time machine uses the radiation 'tag' of the miniscule amount of Carbon-14 that was added to every living thing after that first test to effectively 'date' you for your return. Without it, it can't bring you home again to the appropriate causal 'branch' you came from. ]

[Question] [ What would be a situation in modern times where normal, healthy people would want to get infected by a non-curable, but **non-lethal**, virus? A virus that would have pretty nasty symptoms. There is no compensation for getting infected. The disease would **not** be easily spread, meaning that a person would have to "go out of their way" to get infected, most likely by injecting themselves, potentially even spending large amounts of cash just to aquire it on the black market. There is no sign of any possible cure for said virus. No fantasy elements. [Answer] ### Natural Vaccination. Read about how [Cowpox](https://en.wikipedia.org/wiki/Cowpox) was used to vaccinate against [Smallpox](https://en.wikipedia.org/wiki/Smallpox#Cause), this is our IRL first instance of vaccination against a disease. > > The word “vaccination,” coined by Jenner in 1796, is derived from the Latin root vaccinus, meaning of or from the cow. Once vaccinated, a patient develops antibodies that make them immune to cowpox, but they also develop immunity to the smallpox virus, or Variola virus. The cowpox vaccinations and later incarnations proved so successful that in 1980, the World Health Organization announced that smallpox was the first disease to be eradicated by vaccination efforts worldwide. > > > Your virus could be nasty enough to kill a newly arisen ***lethal*** disease; and for your story building may be the only known way to survive. So for example, a handful of people already infected with your virus survive an outbreak of another disease, "Killingus Allofus" that is spreading ***fast*** and heretofore, 100% lethal. You can catch the "Uglification" virus by shaking hands with an infected person$^1$. In fact, Killingus Allofus takes three weeks to kill you, and if you catch Uglification in the first week you can still survive. Uglification will spread, intentionally, like wildfire. 1 *edit: In keeping with the OP's intent; it would be harder to contract Uglification; say you have to cut yourself and rub infected saliva in the open wound.* [Answer] Because some self-proclaimed health guru claims that it's good for you to have that disease. > > The miracle-virus causes your body to absorb free cosmic energies. Your constantly raising body temperature is proof that it works. > > > The headache you feel is because your brain is reconfiguring itself to become more effective. When the process is over, you will be far more intelligent. Some of our patients even gained psychic powers. > > > The vomiting, blood-coughing, explosive diarrhea and the open sores you have all over your body are actually all the poisons your body accumulated over your life which are now leaving your body. > > > The weakness you feel and the periodical blackouts are also part of the cleansing process. Your body is concentrating all its energy on cleaning you. That's in fact a good sign and shows that it works. Some of us were even able to communicate with alien angel-spirits during these intensive cleaning phases. > > > All of that is of course bullshit. The infected are simply sick. The guru just claims all those pseudo-scientific benefits exist to get people to pay them ridiculous amounts of money for infecting them with the disease. --- Sounds ridiculous? Then you might want to take a look at [the community of people drinking bleach](https://en.wikipedia.org/wiki/Miracle_Mineral_Supplement). [Answer] # An excuse to avoid something worse The virus could be a valid excuse for anyone not wanting to go to war or being involved in a forced marriage. [Answer] Believe it or not, there are people who purposefully seek to be infected with HIV. These people are referred to as "Bugchasers". Lethality: Well, HIV doesn't kill you directly, and those with HIV have near normal lifespans with proper treatment: <http://www.bbc.com/news/health-39872530> cited study: Survival of HIV-positive patients starting antiretroviral therapy between 1996 and 2013: a collaborative analysis of cohort studies; Trickey, Adam et al.; The Lancet HIV , Volume 4 , Issue 8 , e349 - e356 Full text: <http://www.thelancet.com/journals/lanhiv/article/PIIS2352-3018%2817%2830066-8/fulltext?elsca1=tlpr> I'd say that HIV can lead to pretty nasty symptoms and that you get no compensation for contracting it. As for how easily it spreads, well it's not airborne or anything, and Bugchaser do sometimes have to go out of their way to find "giftgivers" to get infected. As for their motives: > > Bugchasers indicate various reasons for this activity. Some bugchasers engage in the activity for the excitement and intimacy inherent in pursuing such a dangerous activity, but do not implicitly desire to contract HIV.[1][2] Some researchers suggest that the behavior may stem from a "resistance to dominant heterosexual norms and mores" due to a defensive response by gay men to repudiate stigmatization and rejection by society.[2] > > > Some people consider bugchasing "intensely erotic" and the act of being infected through the "fuck of death" as the "ultimate taboo, the most extreme sex act left."[3] People who are HIV negative and in a relationship with someone who is HIV-positive may seek infection as a way to remain in the relationship, particularly when the HIV-positive partner may wish to break up to avoid infecting the HIV negative partner.[citation needed] > > > Others have suggested that some people who feel lonely desire the nurturing community and social services that support people with HIV/AIDS.[2] It has also been used as a form of suicide.[4][5] > > > [Excerpted from Wikipedia](https://en.wikipedia.org/wiki/Bugchasing) > > > [Answer] Amadeus's answer is good and covered one of the scenarios I was going to suggest. Here's the second. In the early twentieth century, before antibiotics, patients with tertiary syphilis were intentionally infected with malaria to induce a fever; this was called malariotherapy. <https://en.wikipedia.org/wiki/History_of_malaria#Malariotherapy> Malaria was manageable and is rarely deadly to healthy-ish adults but syphilis had no other working cure. The fever from malaria killed the syphilis infection. You ended up stuck with malaria for the rest of your life but that was a hell of a lot better than a slow decent into madness that syphilis offered. This was such a breakthrough that the discoverer of this treatment got the Nobel prize. <https://en.wikipedia.org/wiki/Julius_Wagner-Jauregg> [Answer] # Birth Control Either the virus itself or the symptoms make it's host infertile. Not sure if you think that infertility is a 'pretty nasty symptom', but never ever beeing able again to reproduce seems a pretty nasty impact. ### Why would they wanna do that? 1. Same as in our society people use birth controls, even permanent. ("I already got 2 kids, i don't want any more"). 2. Maybe to counter a disease where reproduction would kill the parent(s) way earlier than normally. 3. Maybe parents are not allowed to do specific or just common things when having children. 4. Maybe children are just beeing made artificial (like in "Demolition Man" but without human produces sperm/eggs). 5. Maybe clasic contraception is not allowed and results in harsh punishments or death sentence (thinking on a religious scale here). Just my thoughts. [Answer] If it *is* possible to catch the disease and it is *not* possible to *demonstrate* infection was voluntary, then there might be some benefit from a health care program, possibly even a lifetime maintenance that someone could weigh against the obvious drawbacks. [Answer] Obviously they would expect some advantage, real or imagined, from it. People already undergo painful and even (moderately) mutilating procedures - [scarification](https://en.wikipedia.org/wiki/Scarification), modification or removal of body parts, etc. - to express themselves, to "belong" to a group, to pledge their loyalty and things like that. So it could be a fad like many others. And yes, people already spend unbelievably large sums to undergo such procedures. Some body moddings (no links provided - google at your peril) can cost up to £15,000. "[Biohacking](http://www.makeuseof.com/tag/biohacking-creepy-exciting-trend-body-modification/)" is the new word. So it seems to me you need look no further than that, even with your premises of "A virus that would have pretty nasty symptoms" and "There is no compensation for getting infected". Both conditions already hold for, say, the most extreme scarifications. If the long-term symptoms are visible and unmistakable, then you can go with the virus as a mark not unlike tribal or criminal-world extreme tattoos. Or people could choose to believe that infection gives them some superpower - thaumic healing (whatever *that* is), connecting to the inner universe and so on. A workaround to the "no benefit from the infection" - we're threading on a fine line here - could be to assume that there is a non-biological benefit either in *being infected* (insurance compensation, exemption from taxes, ...) or in *being treated* (maybe the symptoms can only be relieved with pleasure drugs, and there is no easier way of getting said drugs). Slightly relaxing the no-compensation premise, infected hosts might really become more sensitive to something and deem this valuable, so much than suffering from the *other* symptoms is still worth it. If the virus gives sensitivity to other infected hosts, and nothing else, it would be a sort of secret club handshake. As long as the symptoms, while severe, can be hidden (otherwise goodbye secrecy). Or if strict segregation of infected hosts is enforced, and you *really really* want to be among the infected - because e.g. your family is there, or you believe that the Rapture will ignore the sane... In [Dark Benediction](https://en.wikipedia.org/wiki/Dark_Benediction), the virus (okay - bacterial symbiote, and it's highly infective) has several compensations: it increases IQ and supplies enhanced sensorial perception - UV, IR, and so on. The craving for uninfected people to infect, which is the most horrible symptom apart from the grey superskin replacing the original pink one, will quickly abate when no uninfected remain around. Changing those premises very little, you could have a virus that people would kill for acquiring. [Answer] **To Get High** We live in a world where [kids lick each other's eyeballs for an erotic kick](https://en.wikipedia.org/wiki/Oculolinctus) and [breathe aerosol from paper bags](https://en.wikipedia.org/wiki/Inhalant) for a quick high, you'd have an epidemic on your hands just because the virus gives you a high like quality Heroin. Heck, if our world is any example, you'd have people lining up to get sick. [Answer] * If people with the virus are sent into isolation (c.f. leper colonies) their close loved ones may want to join them and the only way is to have the virus. * People with the virus may form an exclusive sub-culture (because of rejection by general society or perhaps even because of the effect of the virus on the brain) and a non-infected person may want to be part of that culture. * Some particular class/race/nationality may be held responsible for creating and spreading the virus, a member of that class may feel guilty and infect themselves as an act of personal atonement. * Some historical religious figure may have suffered from the disease and a devout follower may wish to be infected to feel closer to their holy leader. * Having the virus may excuse a person from military service or some other such social obligation. [Answer] There is a comic called "Beauty". Now *Beauty* is a disease, it makes people have headaches all the time and also raise their body temperature. The catch is, people who have that disease become beautiful in one night, and they stay that way as long as they are infected. Their skin refreshes itself, their physical appereance become much more appealing and such. It is super easy to detect someone who has the disease if you know them prior to infection. As it is non-lethal, and at the time of events non-curable, people volunteraly get infected with it. Just read the first chapter and it will give you many ideas on your virus. [the link of the comic](https://imagecomics.com/comics/releases/the-beauty-1) [Answer] **For the same reason people undergo chemo therapy: Because it exchange changes which are considered unbearable with changes you can cope with.** You can also use it to exchange other problems. Let's say we have a disease which very slowly degenerates your physical coordination, agility and strength and makes you handicapped. There is a virus which will stop the disease, but in contrast slowly diminishes your mental capacity: intelligence and creativity. Athletes, watchmakers, surgeons will likely to vote for contracting the virus *because their self-definition and their goal of a fulfilled life is closely associated with their body working properly*. Engineers, scientists and programmers will likely to vote against contracting the virus for the exact same reason: *Their* self-definition is not bound to be physical fully functional, but to their fully functioning brain. So it is not really that the virus does not suck, it simply allows to switch something which is considered a horror scenario for something which still sucks big time, but you can cope with. [Answer] To give the immune system something to do and prevent it from attacking the body's own cells. Being exposed to all sorts of germs is the natural environment in which our ancestors lived and for which we are optimised. This is why hygiene and eradication of diseases aren't 100% positive things. Children who grow up in too hygienic environments are much more likely to develop allergies. There is evidence that in African communities allergies jump from practically unknown to quite significant levels when you eradicate certain parasites. (See also Wikipedia on [Helminthic therapy](https://en.wikipedia.org/wiki/Helminthic_therapy#Anecdotal_evidence).) [Answer] The virus switches your brown fat ([brown adipose tissue](https://en.wikipedia.org/wiki/Brown_adipose_tissue)) metabolism back to the 'factory settings' you had as a baby and keeps it that way. White fat is a food store. You eat too much and your body stores the excess as white fat. When you burn white fat, it provides you with nutrition and, as a side effect, produces some heat. Brown fat is a heat store. When your body burns it, the biochemical pathways are deliberately inefficient and tons of heat is produced. Human babies and young of animals which are born hairless and helpless (rats, rabbits, etc) use brown fat to keep warm with [non-shivering thermogenesis](https://en.wikipedia.org/wiki/Thermogenesis) Why would anyone want to do this? Well, there is a side effect of non-shivering thermogenesis: in laboratory animals which possess it, they can stuff themselves stupid on junk food all day and all night and not become obese. The extra calories are instead burned off as heat by the brown fat. It's been suggested that some of the adult humans who can also eat anything they want yet stay skinny as a rake, have over-active brown fat. (The pharmaceutical industry has been chasing a way of triggering this to happen with a pill since the 80s). So... your virus gives the infected a couple of weeks of extreme symptoms, then dials them back and settles in for the long haul. The infected person, however, never has to worry about becoming obese again. If they eat nothing but pork pies, ice-cream, chips and fizzy drinks they'll put on a BIT of weight (like the lab rats did) but not LOTS of weight. Whether people think this is worth the risk, depends on what you decide the nasty symptoms are. Few folk would want to become blind or impotent to lose weight. More might be prepared to have a terrible headache, vomiting and high fever once a month to lose weight. [Answer] To avoid being drafted? Think late '60s/'70s in the USA. Some people tried a lot to avoid being drafted. If a country in your world is at war, and is drafting people to fight a nasty war, people may want to get infected. They will assume suffering the consequences of the virus is preferable over being send to a war and get killed/be forced to kill. [Answer] Shocked nobody answered this but... Prior to roughly the year 1995, which I still consider "modern times", **this is exactly what was done with [Chickenpox](https://en.wikipedia.org/wiki/Chickenpox)**. Chickenpox is a highly contagious disease that is a relatively minor experience for a healthy child (on the level of having a bad cold). Its so minor, that treatment is generally advised only for the symptopms (particularly keeping the fever down to safe levels and avoiding scarring due to picking at the scabs). However, it can be deadly [for adults](https://en.wikipedia.org/wiki/Chickenpox#Prognosis), and catching it is a much worse experience for them. > > In adults, the disease is more severe, though the incidence is > much less common. Infection in adults is associated with greater > morbidity and mortality due to pneumonia (either direct viral > pneumonia or secondary bacterial pneumonia),bronchitis (either > viral bronchitis or secondary bacterial bronchitis), > hepatitis, and encephalitis. In particular, up to 10% of > pregnant women with chickenpox develop pneumonia, the severity of > which increases with onset later in gestation. > > > Once you've had the disease, your immune system has antibodies for it, so you almost certainly won't get it again. So prior to [the vaccine](https://en.wikipedia.org/wiki/Varicella_vaccine#History), it was not uncommon for parents to send their kids to play with an infected child (aka: a [chickenpox party](https://en.wikipedia.org/wiki/Pox_party)) in the hopes of getting it over with. People who hadn't had this exposure during childhood were doomed to a lifetime of mortal fear of infected children. So that's the situation where this would make sense: 1. Disease is much worse if you catch it when you are older and/or less healthy. 2. One exposure is good for a lifetime of immunization. [Answer] While your virus might have some nasty symptoms, it could also have some **personal** benefits (such as @atayenel and @LSerni have said above), but also things like: - immunity to other illnesses (kind of like a vaccination, but perhaps also more general; this injection makes you get nasty headaches, but stops you from getting nauseous) - a longer life/better quality life: Aldous Huxley's \*Brave New World\* has a similarish thing - people die at age 50ish, but are at peak health and beauty until then - desirable physical or psychological traits - it might mean they don't need to sleep - desperate entrepreneurs/exam candidates/etc. could get ahead if they could dedicate more time to working - it could be a potential cure for depression/anxiety/some other mental health condition. It may not be 100% effective, but people (who look entirely 'healthy' from the outside) are willing to try it. Another thought, more on the **social** side of things (and also somewhat dystopian): if people can prove they've been infected with this, it means that their family/town/business won't have to submit someone randomly to being infected. If a parent could protect their child from possibly being given this virus, I bet there are a lot of people out there who'd be willing to undergo pain and financial difficulty in order to look after the ones they love. [Answer] I'm baffled that this example hasn't come up yet, even as concept. I mean there is even a southpark episode dealing with. What if the treatment for the symptoms is what you actually desire? Referring to the real-world example of getting diagnosed one of several disease and/or disorders to legally consume Marijuana as treatment. [Answer] **To gain a rare but critical advantage in an unusual situation** The second example I thought of was a spy like James Bond; e has a ridiculous skillset that is unattainable for the average person, but vital for a spy who needs to be deployed anywhere in the world on a moment's notice. Bond for example speaks a large number of languages, can pilot basically any craft, and implicitly understands high-tech gadgets on sight (sometimes even exhibiting greater mastery than the inventors). It would make sense for him to be inoculated against any known disease, just in case he gets deployed to the backwater of whatever 3rd-world country this disease comes from. However, it's not stated whether there is any upside of being infected (e.g. future immunity to this or other disease). The "nasty symptoms" called out would disqualify this for Bond, since he needs to be the picture of health, but would be only an inconvenience for a desperate underdog, someone with nothing to lose, or anyone seeking sworn vengeance. Perhaps they have to infiltrate the (equivalent of ) the distant leper colony to speak with a banished king, last holder of the villain's secret weakness? --- The first example I thought of was this: [](https://i.stack.imgur.com/9DqSw.jpg) The Man in Black must have spent some really uncomfortable times getting used to being poisoned, but it certainly paid off in the end. [Answer] Even nasty diseases may have, let's say, *desirable* side effects. Oliver Sacks had [a story about an old lady with "Cupid's Disease"](http://www.walnet.org/sos/cupidsdisease.html) (a.k.a. Syphilis). She certainly liked being infected. [Answer] Healthy people have some responsibility in the society: they should get education, get work, pay taxes, maybe marry. But if you are sick, you sickness is excuse for doing nothing. You can get welfare from Government, you can live with your parents, get money from charity. Everybody has pity for you and you should do nothing, just enjoy your life, for example playing in computer games. [Answer] Here's a big one: **the Government has created a perverse incentive to do so.** Ralph gets Incuria and can't work because the disease is debilitating. His life winds up in a shambles as he can't work or afford medicine. His story is picked up in the media and sympathy flows forth, so they pass the Ralph Law. The Ralph Law doesn't pay people with Incuria directly, but it does pay for treatment so Ralph no longer has to suffer as much and can work again. Everyone rejoices. Along comes Hal. Hal runs a clinic that treats Incuria. It turns out Incuria is a very expensive disease to treat. But Hal discovers that the Government has overvalued the treatments. As such, Hal can treat people with Incuria to their satisfaction for half of what the Government will pay. Hal realizes he can milk this for a lot more, however. He goes to impoverished places and pays people a kickback to become infected. Hal then treats them and turns a tidy profit. [Answer] ## Malicious intent If you have an infectious disease, *you can transmit it*. And (depending on availability, ease of deliberate transmission, and traceability of such actions) there will be people who will go out of the way to be able to do so. [Answer] In a Dystopian world where rape is common-place and laws against it either don't exist or are not enforced, someone might do this as a deterrent to potential rapists. (Although you said it is not *easily* spread, it might still be spread through sexual contact) Or you said it has "nasty symptoms" - one of the symptoms may be numbness/loss of feeling in a particular part of your body - could be considered "nasty" by a healthy person, but to someone with chronic pain, this would be a pain killer. [Answer] Fashion, if being infected became trendy then many would go out of their way for a taste of what everyone was raving about. Having been infected it would be too late to back out once they discovered that the benefits were short lived and vastly overrated. How would being sick get trendy in the first place? Marketing, think Big Pharma, like the song says "this disease comes with a cute chick and a puppy, sign me up", if you have enough people pushing the imagined benefits of a disease that demonstrably doesn't kill anyone then people will queue up around the block to get infected and the company that makes the medications for symptomatic treatment makes a killing. [Answer] Example: Chicken Pox Non-lethal life-long virus intentionally caught. Young people intentionally catch chicken pox in order to avoid getting it at a later age. It is awful to have at all, but the fatality rate greatly increases at older ages. It stays with you for life, and has a small chance to recur. They developed a vaccine for this in the mid 90s, so I don't think people still intentionally catch it. [Answer] Further to Amadeus's comments, civil war soldiers in the USA used to try to self-vaccinate, with unintended consequences: <http://www.atlasobscura.com/articles/how-civil-war-soldiers-gave-themselves-syphilis-while-trying-to-avoid-smallpox> [Answer] As a counter to the vaccine answers, what if a side effect of the virus made lives a bit easier? This also explains why not every single person would be trying to get their hands on the disease. Consider a society where baldness is a form of beauty. It isn't necessary, but much like people who don't brush their teeth, not maintaining your apprentice is sloppy, lazy, or gross. So, everyone wants to be bald. Most people would shave their head in the morning before their shower, but maybe there's a virus out there that prevents hair growth. Maybe this virus also has negative health effects, and baldness is only a side effect. So, not everyone would want it, but plenty would look to get infected to save themselves a bit of time. This could also explain the black market element. Maybe the government is aware of this problem and has banned the sale of infected fluids or something, to prevent the disease from spreading and mutating into something worse. [Answer] One of the nasty symptoms is **infertility**. While undesirable to many people, in a world without decent contraception (or maybe contraception has been banned by the oppressive Dogholic church), this might seem to some as their only means of preventing pregnancy. [Answer] **Due to Aliens** To get kidnapped by aliens who are doing research on sick humans. Or rather to avoid being kidnapped by aliens doing research on healthy humans. Prisoners for life / without parole who want to occasionally see the free world / plan an escape through the hospital. A voluntary human test subject to get monetary benefits from research sources trying to find a cure for it. The thought of finding an eventually successful cure is an added attraction for the subject. ]

[Question] [ OK, I know the question sounds a little bit extreme, but I'm writing a story in which there are two races of a same species, both rational and civilized, with cities and everything an actual society has. Both races are pictured as educated and not prone to violence (they're nice, but serious if needed people) The thing is, both races hate each other, there are people among each race that would go to war if they can and support it, but there is no one who is OK with the other one, like... the most pacifist guy would still sit on the far side of the bus if they see a member of the other race in the front (that was just an explanatory scenario, they don't share cities.) The thing is, the hate they have on each other must be well founded, it should be so that the reader doesn't think "Oh, there is NO way they can be like that", and it must be about race, not politics or religion. Also, it can't be a historical thing (Like, because of something that happened wayyy in the past) because they have the cultural level and the ethics to let go of the past if that was the case. I was thinking of maybe something biological, but I don't think a virus or disease might work because I don't think it's possible for they to have evolved to the point where they share a planet on equal grounds (no race is noticeably poorer or richer in resources or education). Although, I'm open to suggestions on other areas aside from disease. Finally, it can't be simply "nature" or because they are pretty much like humans, they can ignore their nature because they're rational. EDIT: I'm going to give more details because I feel that some people who answered didn't get an important part of the question (probably my fault, I'm not from an English speaking country) The idea here is that the reason not only isn't present in our world, but it's most likely that it is impossible that it applies to our world. Many people say in comments that it doesn't have an answer because I'm restricting the answer so it doesn't involve politics, history or religion, but I never said anything about geography, biology, chemistry or any science. Because its hard but very important in the story is why I'm pretty much open for you to do anything with the world, for example, does your reason need for them to live in separate continents? Sure, go for it. Thanks again for everyone who has answered, you have given me a lot of possible reasons I haven't considered. [Answer] The [uncanny valley](https://en.wikipedia.org/wiki/Uncanny_valley) would suffice: [](https://i.stack.imgur.com/jmjX2.png) The uncanny valley is theorized to detach us from the corpses of our dead friends. We strongly dislike things which have a similar level of human likeness as a corpse does. If two groups were close but not quite the same, it would be very possible for each group to fall into the other group's uncanny valley, generating extreme dislike. [Answer] As presented, you show that you don't actually understand tribalism, racism, sexism, or pretty much any other -ism. Let me explain, but don't look for politically correct terms or comfortable lies. Systemic racism comes from one of many sources: * Endemic social pressures. (If your child doesn't have certain traits, they will not be 'desirable' mates, and thus your genes will die out) > > This is true of pretty much everywhere on the planet (African, India, Asia, North America) where there is a socio-psychological pressure to have 'lighter-skinned' offspring. The unwritten 'rule' is that people with lighter skin are 'more attractive', 'more trustworthy', and 'a better pick for a life partner'. > > > * Lack of social interaction. (US versus THEM, tribalism) > > Any tribe has learned, as a group, that what they do not know can kill them. Don't think modern times, think stone age (you know, when our instincts needed to be sharpest in order for our species to survive: you've never seen a lion before, that's a lion, KILL IT!) This brand of racism (tribalism) comes from the ingrained, almost pathological, need to protect what you know and love from what you do not know or do not love. > > > * Lack of knowledge > > Ignorance is the source of much of the world's problems. If I know nothing about you, and I meet you for the first time in a situation that causes me to be cautious (like two groups from these two civilizations you speak of), you and I will both be wary of each other (as explained in my previous point). I have no reason to be nice to you, you have no reason to be nice to me. If we are both brought up in the same way (meaning both are brought up to be friendly and accommodating, even with people we do not know) then there will be no problem. However, if you are brought up to be accommodating, and I am brought up to ignore or take what I need, then we cannot possibly understand each other. The lack of knowledge will cause friction, and that friction will not lead to anything good. > > > * Competing for resources. (This rock isn't big enough for the both of us) > > Another very real option is scarcity. If there is only enough for one of our civilizations to survive, then I'm going to kill you to make sure my wife and kids have a better chance. Some might disagree and argue that human nature would lead us to cooperate (and there are some psychological and sociological studies to back this up). However, if that were the case wars would cease in our world... That isn't the case, last I checked. > > > * Pride. (I am important, therefore you cannot be) > > This one is dependent on how the peoples are raised, both as individuals and as a tribe. If you have two groups believing they are each more important than the other, then they will not care how they treat the other. But this boils down to the individual, because if the individual is taught "A man should not be judged by how he treats his superiors, but rather how he treats those below him", then even if one feels superior, hate will not be bred between the groups for that reason. > > > That means the source of this rift, as you desire it, MUST stem from: limited resources. Because every other option goes against your stipulations, or doesn't require a deeply seeded 'hate'. Though I still feel it isn't needfully 'hate', more a love for someone that needs the same things you are trying to take from me. For a real-world example, see Feudal Japan. [Answer] Odor would probably be the easiest way to justify an enduring race hatred. Just as there are pheromones, which induce attraction within those who smell them, there are probably also anti-pheromones which induce negative emotions and even hatred. Make your blue skinned people's pheromone an anti-pheromone for the orange skinned people and vice versa. Then limit both races access to soap and perfumes. Then bring on the bloodshed! [Answer] ## Controlled release of a Hate gland Greetings, Visitor Human. You wish to know why Alien Orange and Alien Green hate each other? Very well. Come, sit here on the Orange side, with me. Ours is a rational species with a long history, and a wealth of medical knowledge. We've applied it mainly to ourselves. We have our love, our hate, jealousy, hope, like you. But unlike your mysterious human minds, each of our brains is just **one big set of glands**. When the Happiness gland fills, it needs to be released. When the Sad and Pity gland fills, we know it too, and we watch your Earth, the better to **release those emotions**. We also have a Hate gland. We discovered it long ago, and its discovery has prevented us from destroying all life on our planet. Plus our solar system. Also your puny Earth. Because our Hate gland fills, too, and it tells us to Hate. All the time. How do we release the burden of the Hate gland **safely**? We hate each other. So, I hate Alien Greens, for the better of our world. There's one passing right now. Watch me stare at him, hatefully. They understand it of course, and they hate us Alien Oranges right back. I hope you understand my justification. Farewell, and enjoy your stay. You can get back to the transports if you just keep right along that Orange Wall. Also, perhaps you should stay clear of that Alien Green, now that he's seen you talking to me. Such is life here on Planet Powderkeg. [Answer] This is a bit of a stretch, but could this "racism" be the result of years and years of deliberate propaganda by the respective governments of each side? In the same way that a prolonged marketing campaign has led us to associate diamonds with love, romance and value (spoiler, diamonds have nothing to do with the above), the governments of each population could have spent years educating their people to hate the other side, to the point that it has now become ingrained and instinctive. A possible reason why each government would want to do so could be to establish a "common adversary" and thus enforce unity within their own community. It sounds like each population is self-sufficient. In this case, such a scenario could be the result of collaboration between both governments (for simplicity henceforth Red and Blue), along the lines of "I'll teach my Reds to hate on your Blues (and vice versa) so that my Reds will stay loyal to ME as long as I unite them against the Blues." This is a bit like the "War is Peace" argument from 1984. [Answer] # Predator vs Predator historically You have two sentient species... but maybe they used to be a hunter/prey relationship. Both of them used to eat the other for dinner. They are well past that today, both feeding on other prey species, but in the back of everyone's mind, everyone knows that the other would taste REALLY GOOD. And every few years, some whack job tests the theory out and, sure enough, he/she reports that the other species is The Best Thing Ever Tasted. The whack job gets tried for murder, and convicted, but that just adds to the constant tension. [Answer] ## Feeling uncomfortable is all you need You seem to want some built in difference to cause this, several examples spring to mind: left and right handedness, height, body shape, face shape but I'm sure there are many more. For handedness and height it could be that every time one visits the city of another they feel uncomfortable. Stooping through doors or having people tower around them, small things like day to day objects not being where they expect (handles on toilets for example). Body shape would mean the chairs in another city are uncomfortable. There are many examples you can think of. If one people are constantly made to feel uncomfortable when visiting another they will be on edge even if they can't really put their finger on it. Face shape is another possibility, perhaps they each find expression of emotion hard to read on the face of the other...this is going to make you feel uncomfortable too. Basically racism isn't founded in on some well thought through emotions but on a feeling of discomfort, something that makes you prefer you and yours over 'them'. This divide is the basis for all racism but above are some ideas of how it may be perpetuated. [Answer] ## Differing Values The Dune series by Frank Herbert imagined some serious racism between the [Tleilaxu](https://en.wikipedia.org/wiki/Bene_Tleilax) and other groups, although all were humans. Some of this was based on physical appearance, but there were also a large part of it based on the different values of the groups. For example, the fact that they never saw Tleilaxu women was concerning to other races (leaving aside the rumours), and if I remember correctly the Tleilaxu were equally offended by the other races permitting their women to wander freely in public. We also see this in the real world. Sometimes we find people who dislike other groups not because of their physical characteristics, but because of their differing culture. > > "*The way they treat animals*" > > > "*The way they treat their older family members*" > > > "*Their obsession with money*" > > > "*The way their women dress*", etc. > > > So all you need is groups with differing values, and you have a *reason*. ## Justification But to make it strongly *justifiable*, I think you would need to demonstrate some measure of harm. For example: > > *"They teach my son bad habits."* (e.g. play date with a [Ferengi](https://scifi.stackexchange.com/questions/150600/are-the-ferengi-racially-discriminated-against-by-members-of-the-federation)) > > > *"The perfume they wear makes my eyes smart."* > > > *"I am allergic to their clothing."* > > > *"Their agricultural processes pollute our water."* > > > Some of these problems might be reconcilable, if (individuals from) the two groups wanted to work on them. Others might not. ## Existing Conflicts There are a multitude of situations in the real world that you could look to for inspiration. Differing religions (the conflict in [Ireland](https://en.wikipedia.org/wiki/Irish_revolutionary_period), or the one in Palestine-Israel), competition for resources, or indigenous people versus colonists. [Answer] **birth defects** nearly all human societies have a strong taboo against mating with family members. this can be easily explained by the dramatic increase in birth defects in the offspring of close relatives (e.g. siblings, parent/child). this is due to the negative effects of various recessive genes and the fact that the entire human race is extremely inbred (e.g. compared to chimpanzees). obviously, close relatives don't usually hate each other, but that's also explained by our genetic imperative to help our close relatives reproduce. so, the question becomes: what if there was a group of people that my people liked, but almost certainly would cause birth defects if we mated with them. if so, we would evolve lots of aversion mechanisms to ensure that never happened. let's say at some point in the history of this species there was a mutation in a gene for forming skin. anyone with 2 copies of the "normal" version are fine. anyone with 2 copies of the "mutated" version are fine. but if you have 1 copy of each, your skin constantly peals off painfully while excreting a stinky green goo. how the first person with this mutation managed to reproduce at all is a mystery, but i'll assume he was not a nice man. in any case, his descendants eventually formed their own community. once that community became isolated from the "normal" community, they eventually all had 2 copies of the "mutated" gene, so they looked normal as long as they didn't interbreed with the "normal" population. fast-forward a few thousand years and both populations have developed strong social, political and genetic deterrents from interbreeding (e.g. taboos against talking to "others", laws forbidding interaction and hormonal repulsion making "others" stink). no one can remember what happens when they interbreed because it never happens. perhaps in the last few thousand years both societies have developed genes to handle the "mutation" without any ill effects, but the secondary repulsions remain. perhaps even the hormonal repulsion has eroded away, so they smell fine to each other. now, you have two societies that could interbreed (and otherwise interact), but simply choose not to for historical reasons. [Answer] If we're talking about humans, you don't need much. Modern, globalized culture as we see today is kinda new. Back then being from a different clan or tribe would be enough to get yourself shunned from society, even if you had the same skin color or general appearance of the people you're trying to mingle into. But if you *were* different, chances are you would end up having a really, really bad time. Just check all the fuss we *still have* because of stupid things like skin color. Just give your races some sort of different skin or hair color, or maybe even some sort of different type of hair. Make then "Blues vs Oranges", or "Curly Hairs vs Balds". Those types of differences shall be enough to *explode* a society if their leaders are fanatical enough. If you don't want to make the difference on your societies being "flavor", use their country of origin as a basis. Civilization A always lived on the country, while Civilization B is a newcomer and grabbed a slice of land for themselves. So, you have a conflict over land that, given enough time, would evolve to racism. --- But really, you don't need much to justify your people being racists than just picturing them as human-like. We are *that bad*. [Answer] Races are socially accepted groupings of genetic traits that distinguish those who have those genetic traits from those who do not, typically limited to genetic traits outwardly observable, such as facial bone structure or skin color. However genetics carries more than looks, including aggression, certain mental illnesses, and aspects of intelligence. If traits such as these were more pronounced between the socially constructed groupings (resulting likely both from a biological side--how their genes interact--and a social one--both how the races are defined and how culture evolves within the races), the biologically-driven foundation of personalities and world views becomes more and more pronounced. If one race abnormally highly suffered from schizophrenia, another race had abnormally high levels of autism and low intelligence, and another race was extremely aggressive at a biological level it'd be very easy to form racism *grounded in scientific biological facts.* This strikes us as wrong as humans, since we don't see these traits concentrated in one race or another to any socially-defining degree. However if one race is biologically drastically more prone to have X or Y negative personality/mental trait, racism becomes... ...Well I don't want to say "justified," but it does seem more justifiable. [Answer] Something a bit more unconventional but still biological: **Mutually Malign Symbiotic Bacteria** What if each race's biological functions require (similarly to humans) that certain kinds of bacteria exist in their systems? The catch of course is that the bacteria species A needs to survive actively attacks species B, and vice versa. Thus if members of the two species are brought into close proximity for lengthened periods of time, members of both species become ill and each species blames their sickness on the other. Thus the children of each species are taught to hate and avoid the other species for their own safety, and the cycle continues. In addition, the exact functionality behind this reaction could also only be ascertained from a full examination of the other species (e.g. by autopsy) and the person performing the examination would have to be protected to prevent being affected, which would make it particularly hard for the species to fully understand the situation, hence why the behaviour might persist for a great many years. [Answer] Your premise that it can't be natural is invalid. Simply saying someone is rational doesn't mean they can overcome their baser evolutionary drives. Take tribalism: it's the reason we look for people who are like ourselves, and it has a large part in the existence of nearly every prejudice, from political bias to racism. Simply being different in some way is grounds for some caution or even outright fear or hatred, from an evolutionary perspective. As for the justification, it could be any odd lie about the other race. "They're violent, they'll rape our daughters, they're a corrupting influence that should not be approached under any cirumstances", would all be "justifications" for racism. [Answer] Why RedRace and BlueRace hate one another * There used to be one race (OriginalRace) * Cloning technology turned this into two highly similar races (OriginalRace and CloneRace), but which is which is lost to history * That's it, that's the whole reason they hate each other. **Being a Clone Sucks** For a take on the individual version of this problem: [Cloning Blues (TVTropes)](http://tvtropes.org/pmwiki/pmwiki.php/Main/CloningBlues "(Warning: TV Tropes)") There are many variants (evidenced by the TVTropes examples) but the basic premise is that the knowledge that one is a clone can lead to a wide range of psychological issues dealing with the ensuing identity crisis. **Being a Clone Sucks -- Uncertainty Edition** One of my favorite takes on this is when the cloning process somehow leaves doubt as to which individual is the original and which is the clone. Each wants to believe that they are the original (without evidence suggesting it), mostly to side-step all the nasty implications of being a clone. However confident an individual may appear, the nagging doubt that *they may not be real* is always in the back of their mind, and unlike their "definitely a clone" counterparts, it's unlikely they'll be able to accept and get over it. **Why Uncertain Clones Hate Each Other** This also naturally leads to negative emotions between potential clone counterparts. Let's assume the following axioms and see what follows: 1. I want to prove that I am *real* 2. Only one of us is *real* (2) directly implies (3) 3. Any evidence supporting the hypothesis that I am *real* also supports the hypothesis that he is *fake* It's easy to rewrite (1) and (3) to: 4. I want to prove that he is *fake* (4) From rewritten my counterpart's perspective: 5. He wants to prove that I am *fake* (1) and (5) are directly at odds. We have a source of conflict. We can both be rational, and we can both be ethical, but as long as our desires are mutually exclusive we will find ourselves on the opposite sides of things quite often, and that can bleed through. If we add the following assumption: 6. clones are commonly expected to be inferior in some way to the original (more susceptible to disease, not quite as strong, not quite as smart, etc.) there are a few more consequences: 7. any time I outperform my counterpart, I'm relieved and happy: This is evidence that *I am real* and my counterpart is *fake*. This could even lead to pity, which may be resented by my counterpart. And it's corollary 8. Any time my counterpart outperforms me, I'm forced to confront the possibility that *I might be fake* again. This is unpleasant and uncomfortable. This always occurs just as my counterpart is experiencing the comfort and joy that comes from being secure in his reality. A pattern emerges where my happiness is correlated negatively to my counterpart's happiness. The strength of the correlation could be strong or weak depending on just how much our sense of identity is important to us vs. our other sources of happiness, but it will always be negative. **Making it Societal** Possible Origin Story: > > RedRace created Clones for slave labor. They ensured that they could not reproduce with an Original to prevent the nasty question of what rights should go to individuals born to one RedRace and one Clone parent, but otherwise left the genome as unaltered as possible, so they could easily be a drop-in replacement for Originals in every sector of the economy (even traits like inbuilt servitude might prevent them from functioning in some roles or functions). Clones, as a result of the slight genomic alteration, also ended up with Blue Skin, and were thus dubbed BlueRace. BlueRace didn't like the current world order, revolted, and during the war captured and deleted all records which proved RedRace was the OriginalRace, and started an intensive propaganda campaign claiming that BlueRace was the OriginalRace. Hundreds of years after the end of the war, no one alive knows the truth for certain. Almost everyone agrees that regardless of the truth, both OriginalRace and CloneRace individuals have the same set of rights and responsibilities, and should be treated as equals. Despite nominally open borders, it's far more comfortable to avoid being reminded that *someone is fake* (especially without members of your own race near you to back you up) by going into OtherRace territory and interacting with members of OtherRace. > > > Societal achievements could take the place of personal achievements for purposes of determining which is *real*, spurring advances in technology, governmental systems, or ethics. Individual achievements may still be seen as supporting evidence for one race's superiority, especially among the less "enlightened" members of the species. Sports and other competitions would be extremely tense for these reasons, especially any sport which involves referees for scoring or rule enforcement like gymnastics or even football. Any achievements made by RedRace will be attributed to luck, foul play, or just "not being that important" by BlueRace, while they will emphasize any area where they are outperforming RedRace. **Bonus Round** If religion teaches that only "God's creations" have a soul and get to enjoy the afterlife, being *real* has much stronger implications and the tension goes up a lot, even if both races follow the same religion, and even if the religion preaches tolerance and love for every living creature, clones included! RedRace zealots could word tirelessly and donate all wordly goods towards helping BlueRace people live comfortable and fulfilling lives, on the premise that they have the entire afterlife to enjoy themselves, BlueRace only has their 80(?) year life. They legitimately practice love, compassion, and self-sacrifice, but it's rooted in the assumption that RedRace is *real* and BlueRace is *fake* (and somehow inferior) so it ends up being divisive all the same. [Answer] **Zootopia** I think it would be just enough for a more or less literal racism if biological differences between the two made it that one of the races was strictly carnivorous and the other strictly herbivorous. The difference could be the effect of a virus changing their digestive systems. Originally, both races were omnivorous, much like humans, but they were different enough so that their organisms responded differently to the same virus. So now it's easy to distinguish between the two even though the difference in their respective visual traits has nothing to do with the main problem. Since their diets are so radically opposite, it's very difficult for both races to live in the same place. And if they have little opportunity to socialize with representatives of another ethnic group, it's very easy to perceive them as a threat. False stories start to spring up. The other culture starts to look extreme and barbaric. And so on. The arguments against carnivores are pretty simple: They feed on carcasses. They require slaughter houses. They (everyone knows that) drink blood. They are treacherous and cunning: after all they raise cattle, acting as if they were friends to the innocent animals, and then they kill them. And what if... what if they eat us, herbivores, too?! There are stories about missing children, you know. It's a bit harder to think something out against herbivores, but this is not impossible. Carnivores are shunned and hated by the herbivore society, so they tend to come up with ideas which show that in fact the carnivores are better. Herbivores are weak. They prefer shady politics instead of a simple, honest conflict. They have no honour. Long time ago everyone we were all carnivores and only they changed and now they lie that we were changed too. When a carnivore mates with a herbivore, the child dies. See? (You can elaborate on that: what if living or dying, or the diet, of the offspring depends on who is the father and who is the mother, or on the sex of the child?) On top of that, herbivores are hypocrites. How do think, why there is no cattle in the herbivore lands? What happened to all the animals? Huh? Huh? [Answer] In real life, among human beings, very little actual rational justification is needed for the development of lasting and consequential racial animosity. In fact, the animosity is sometimes sharpened when the groups are actually very similar from objective standpoints. Notable current and historical examples include the Jews vs. the Samaritans, India vs. Pakistan, Hutus vs. Tutsis, the Serbs vs. the Croats, Korea vs. Japan and the English vs. the French. In a [famous experiment](https://en.wikipedia.org/wiki/Jane_Elliott), a schoolteacher successfully and reliably elicited typical racist behaviors from a group of schoolchildren simply by dividing them into two groups based on eye color, and favoring one group over the other. For your book, I would suggest some historical circumstance in which one group was favored for some trivial trait. To make the hatred especially sharp, let the other group have now gained the upper hand. [Black Skins, White Masks](https://en.wikipedia.org/wiki/Black_Skin,_White_Masks) might be a good resource for you to read. [Answer] The reason that racism is problematic in our world is that it's based on a lie: that people of other races are inherently different, in a way that makes it harmful for *them* to interact with *us*. The simple truth is, we're all human and we all have approximately the same capacities for good and for evil as everyone else. If you want it to be justified, *take that lie and make it true in your world.* There is something inherent in their nature that makes at least one group, if not both, fundamentally harmful to the other. Subtle biological changes can exist between human subraces. Caucasians are almost unique in their ability to tolerate lactose beyond childhood. Native Americans don't have the genes for facial hair. IIRC the Japanese have an enzyme that improves their ability to digest raw fish. Sickle-cell anemia is common in people whose ancestry traces back to parts of Africa in which malaria is endemic, because the altered blood cells are resistant to it. And so on. Perhaps in your world, race A has a pheromone that is harmless to them but triggers allergic reactions in many members of race B. Now it is literally not safe for them to be around each other. That's all it takes. [Answer] I think the key to inflaming racism is, counter-intuitively, denying that racism exists. People often conflate racism with celebration of diversity. Little Italy, Chinatown - these aren't racist vestiges, these are celebrations of communities that have naturally aligned themselves along dichotomies like race, language, culture, etc. People naturally organize themselves into teams, into sides, etc. It's a political calculation. Together, as a community, you can vie for jobs, neighborhood development, other things. The key isn't to ignore race (which would simply strip less powerful communities of their ability to organize politically), but rather to integrate multiple communities into a cohesive functioning society where race is a basis for cultural commerce instead of conflict. However, in your society, for whatever reason, multiculturalism is anathema. There isn't even an acknowledgement of culture, or a concept of race. They're simply intent on steamrolling each other until the one "true" culture dominates. In essence, it has to be a psychological change. Trying to actualize race via outward biological devices undercuts its core abstractness. Race may seem irrational to you, but I'm reminded of what Douglas Adams wrote about horoscopes: > > In astrology the rules happen to be about stars and planets, but they could be about ducks and drakes for all the difference it would make. It's just a way of thinking about a problem which lets the shape of that problem begin to emerge. The more rules, the tinier the rules, the more arbitrary they are, the better. It's like throwing a handful of fine graphite dust on a piece of paper to see where the hidden indentations are. It lets you see the words that were written on the piece of paper above it that's now been taken away and hidden. The graphite's not important. It's just the means of revealing the indentations. So you see, astrology's nothing to do with astronomy. It's just to do with people thinking about people. > > > [Answer] Keep it simple. A natural phenomena has caused members of the same species to evolve some physical trait that is mutually disturbing to other group. Pick one or more of: 1.) Each group smells positively disgusting to the other group due to some environmental change in their body odour. Being around them is literally nauseating. 2.) Same concept but the other group looks positively ugly or otherwise offensive (too bright, too dark, too purple, too trapezoidal, whatever). It literally hurts to look at them. 3.) They sound *sooo* irritating. Listening to them is like nails on a chalk board. They are just too damn loud, or too quiet, or their accent sounds like childish gibberish. The traits need not be so extreme as to make them a different species for the two groups to be mutually upset by the presence of the other. For 2 and 3 even distance is no cure - audiovisual communication would remain an unpleasant chore that would hardly create a friendly relationship. If you want something more technological it could be as simple as each race has a stash of WMDs. They constantly live in fear of each other. If you want something more unusual consider an evolutionary change that caused the blood of each group to change chemically into something dangerous to the other. Maybe one group has acidic blood and the other group is highly basic, so close contact causes burns. Or maybe in the territory of the other group people have a reaction with the air that causes them to randomly spontaneously explode if they aren't wearing special containment suits. [Answer] ***Incompatible biologies*** including each species associated ecosystems such that the systems nor the sentients can share the same area and when one ecology expands the other must shrink, making it a zero sum game. [Chirality](https://en.wikipedia.org/wiki/Chirality_(chemistry)) would work well to create such immersible yet otherwise identical ecosystems. One species would be levirotary the other dexter (left or right.) They couldn't coexist in the same ecosystem because some of the enantiomers would be toxic to the other side. Otherwise, they would look and act identical. The sentients could not eat the same foods from the same cropland nor intermarry, It would be a true US vs Them, winner take all, planet wide, ecosystem anchored, war to the knife. The only hitch is that it wouldn't really be racism. We're all taught that racism is irrational but for much of the past 500 years it's been quite rational, judge by the behaviors it evoked even though the fictional rationale kept shifting. Racism is a fictional construct with a functional purpose. It creates a sense of genetic-kinship within a group who are not actually related beyond superficial appearance and/or living in proximity. That sense of kin-indentity was need to form larger and more cooperative units. In the middle-ages anywhere in the world, if you told a noble they were in anyway genetically related to the peasants who tilled their fields, the noble likely would have literally kill you for the insult. A couple of centuries later, they would have replied, "well we are all English, French etc and then eventually "white." Yep, the distant past sucked so bad that what we today regard as one of our greatest evils, represented at the time, a big step forward in the moral advancement of humanity. Counter-intuitively, the more egalitarian and democratic countries became, the more they needed that sense of collective identity, and the stronger racism grew. Eventually, though the merit driven culture triggered by the evolution of corporations, destroyed the functional basis for racism just as it had for class (it's not just coincidence that the anti-slavery movement was almost entirely comprised of Corporate elites e.g. Hosiah Wedgewood.) The problem with many parts of the world today, is that they haven't progressed up to racism yet and remain stuck in seeing only their extended families as being moral equals to themselves. The problem with the Chirality scenario is that each side would present a real material danger to the other side so their "racism" would not require a fictional justification. The justification for hating the other side would be quite real and rational, in terms of it being rational to preserve one's own life, and lives of one's family over the lives of others. Ruthless, but rational. Call it Darwin's diabolical calculus. Not sure its what you're looking for but it's the best I can think of that matches your criteria. [Answer] When you get right down to it, you're trying to (if I understand the question correctly) come up with a rational justification for hatred, which is an emotion. *You can't rationally justify an emotion*, emotions are rationally neutral. The reason is that the way you would normally justify that some course of action is rational or irrational is to examine its effects on the world - if the action will lead to a positive outcome (for some definition of "positive"), then it's rational. Emotions in and of themselves have no effect on the world. You can say that some action motivated by an emotion is irrational, but then you're not discussing the emotion anymore, just that action. It would have been irrational no matter what motivated it. The best you can say is that since hatred feels bad, it's irrational to feel hatred, but then that's a bit like saying it's irrational to feel pain. What you can try to justify rationally are some of the *symptoms* of racial hatred, ie some of the actions that hatred often motivates. Segregation, abuse, war, genocide. Why would it be rational to do any of those things? At the basic level, in order to justify that *anything* is rational or irrational, you need to have a value system. Like I said, to say that something is rational is to say it will lead to a positive outcome, but the definition of "positive" is arbitrary. For humans, for example, we tend to assume axioms like "dying is bad" and "physical pain is bad". If your two alien species had biologically in-built value systems that conflicted with one another, then it might seem rational for one to exterminate or at least avoid the other. But wait, you say. Surely if these are perfectly rational beings, they can see that their value systems are fundamentally arbitrary? Surely they can see that they shouldn't despise each other because of what kinds of likes and disgusts their biology happens to have built into them? Well, yes, if you boil it right down, maybe these beings aren't *perfectly* absolutely rational. But consider this: can you rationally justify that murder is bad? Is it? If no one knows or cares about the victim, at least? If they don't suffer while dying? Who have you hurt? They're not around anymore to care that they're dead. The fact that we value not killing each other is just a (evolutionarily sound) biologically innate value that human beings have. This is the kind of thing I'm talking about. Not values like "women shouldn't go to college", values like "eating cake is better than being tortured to death". This is the same as @joeytwiddles answer, but on a much deeper level. You need two species to have values that satisfy four conditions: 1. They are absolutely biologically innate on the same level as the human aversion for death and suffering. 2. It's impossible to build a society in which both sets of values are satisfied at the same time. 3. It's possible to build a society in which *either one* of the sets of values is satisfied, so that you aliens could at least have their own societies and civilizations. 4. It's plausible that a species could have survived natural selection with those values. As an example, I don't think it's difficult to imagine a species who don't have a problem with torturing and killing people. Imagine a kind of an ant-like species in which each individual only values advancing the population as a whole, and doesn't actually have any fear of death or pain, or a tendency to emotionally attach themselves to individuals (a.k.a. they don't have a concept of friendship or love). Evolutionarily, this is just taking quantity over quality. This species would have no problem with mass murder, probably including of other species. How well do you think we'd get along with them? [Answer] 1. The two races formerly were hostile towards one another. 2. They are more enlightened now, and just came off a long period of peaceful cooperation. 3. The races must be kept separate, because intermarriage delivers a lethal combination of genes to offspring. 4. Each independently discovered a technologicAL means of seeing the future, albeit fuzzily. 5. In the future they see, one of the races has been apparently exterminated. 6. The truth is, a mutagenic virus caused changes to the "exterminated" race that reversed the mutations that made them distinct, causing the races to merge, so really no one was exterminated, but tell them that after the war that kills most of both populations and creates the virus in the first place. Self-fulfilling prophecy. [Answer] Technology / Transhumanism 1. Race 1: Normal Species A 2. Race 2: Abnormal Species A * Clones * Tech-Augmented Species A * Gene scrubbed / uberspecies A * Species A who transferred their consciousnesses into new bodies. Race 1 will view Race 2 with suspicion, unease, and just plain fear / hate. They think they are better than us. They are so creepy. They are an abomination. Why do they need a plasma cannon grafted to their torso unless they intend us harm? Race 2 will view Race 1 as a relic. They are barbarians. They refuse to transcend with us. They think they are so much better. They are just so disgusting with those fleshing bits. The constitution gives me the right to free expression and if that means adding tentacles to my arms then I will add tentacles to my arms! [Answer] Maybe it is something as stupid as one society believes that the best way to further species progress, it would be to do stem cell research. The other society, who is more grounded by natural means of progression may find stem cell research to be too dangerous and could harm the genes. This breaks into fights and difference of opinions that lead then to years of hostility. The very definition of racism is the belief that one race is superior to the other. Maybe it is the belief that This race of XXXX, which has horns, is much more appealing and gives them the feel of the alpha race over the others. Could be something as silly as one race has hair and the other doesn't which in their eyes makes each other look ugly. One thing you shouldn't do and I would probably re-word the question is that you aren't justifying racism, but rather providing a reason it exists. Justifying it would mean that this behavior is okay. Depending on your world's set of values, racism isn't something that you justify and validate and say "yep, you are right, their lack of horns is pretty beta. You have every right to be jerks to them". Within the races, they may justify racism to themselves for their reasoning, but to the readers and the rest of the internal world species seem very silly. Depending on where you are trying to go with the story, you will more than likely want to, at some point, show some form of realization that the justification they held was wrong as an attempt of character growth. [Answer] What about basing the racism, on some other -ism? E.g. sexism: one of the races is intensely misogynistic, and treats their females with disdain, scorn, dismissiveness about sexual assault, and only pays them 74% of what an equivalent male would be paid; whereas the other race has deep-seated misandry, and like the mythical Amazonians subjugate their males nearly as slaves. While each race "accepts" that the other race functions as they do, and realize that they cannot change things - they are still offended by their racial culture, even repulsed by it. --- Here's another idea, because I think that one is too realistic for you. Each race has a certain magnetic alignment, giving off a slight, but significant, charge of magnetism. The key is that each race is aligned opposite to the others. And while "opposites attract" may often be true, in this case the opposing magnetic charge actually makes the other race physically queasy, like deep down in their gut. They are literally sick to their stomachs from being around the other race. They probably don't even understand this cause, and maybe don't even realize they are affecting the other race too. All they know is they are affected negatively when the "others" are around. [Answer] If you could have them at significantly different altitudes, that could work. One race lives in the deep valleys and low plains of one continent. The other lives in the high mountain valleys and plateaus of the second continent. The lowlanders would have trouble moving about in the highlands, due to the thin atmosphere. The highlanders would be very uncomfortable in the lowlands because of the high humidity. You'd probably need an altitude difference of about 12-15000 feet to get that kind of effect, but it's nothing a creative geography can't produce. [Answer] Someone above mentioned pheromones. What if one of the races developed a pheromone which they can release as a conscious action, which makes the other race do their bidding? I'm thinking the pheromone acts like an airborne version of sodium pentethal. Obviously, the natural thing for the Affected race to do is to develop gas masks, from a very early point in their tool use, but for both races on this planet, pheromones are an important method of communication, and they don't want to wear these gas masks all the time. Eventually, the Excretor race promises not to use that particular pheromone when an Affected is around. But this pheromone is important to the Excretors' communication, and they resent not being able to use it. They are allowed to use it in sealed-off spaces (in a city full of people with a scent-based communication system, these are very important) that are designated as Excretor spaces, and as a gesture to this, public buildings and transport often has an Excretor space and an Affected space. I think this would work better if the Affected are in power, but hate the casual way an Excretor can get control of them, while the Excretors resent the way the Affecteds impose on them and deny them their ancestral rights because the Affecteds are weak and couldn't cope if they did. [Answer] Or you could use the reason that we have in the real world: Political leaders trumpet the flaws, crimes, and dangers of the other race (inventing such flaws, crimes, and dangers if necessary) in order to manipulate their own herd, for the sake of influence and money. Much of the racism we have today would simply die out if there wasn't someone, somewhere who was making hay out of it. I could cite specific examples, but I don't want to start a fruitless debate. [Answer] Some thoughts ... * Could be Race 1 is constantly, innocuously giving off a scent which is similar to Race 2 sex pheromones. This offends the strait-laced Twoites. The Twoite's contempt sparks a reactive dislike of the Oneites; they come across as puritanical snobs. * Could be Race 2 are scavengers; they eat bones, and offal, and ordure. This grosses out the Oneites, who in turn sip nectar from the flowers the Twoites revere. Every time a Oneite sups, he's virtually raping the Flower-Goddess. * Might be that one group is just *scary*. If humans ran into a bunch of aliens that looked like hideous spiders, we'd run screaming for the hills. * Hmm ... perhaps Race 2 are photosynthetic. They give off poisonous oxygen and shed algae which does the same. The Oneites know about planetary eco-mechanics, and know that the Twoites are slowly killing them. Just. By. Existing. Note that it only takes *one* group to get things rolling. If the Onites hate the Twoites or disdain them, the Twoites will pick up on that and respond. [Answer] Hopefully this is more useful to your story.... One of the races has evolved the ability to foresee the future and have foreseen their genocide at the hands of the other race. ]

[Question] [ Set in the immediate future, mankind visits Titan, moon of Saturn for the first time. A manned space station goes into orbit around the moon once every 4-5 hours. Actually there have been many people being sent all over the solar system. Some missions are solo. Without FTL and artificial gravity why is nudity prohibited in space, at all times? There is no policy on possession of adult materials or even engage in intimate activity, just no nudity strictly! [Answer] # Housecleaning in Zero-G Think through the amount of body hair and skin flakes a human sheds each week. On Earth, you take a vacuum cleaner or a mop. Still, fluff collects in hard-to-reach places. No big deal, really. The combination of zero-g and artificial life support systems makes fluff a greater problem in space. The solution? Almost-full-body clothing and hair nets are worn just about everywhere, except in the bathroom and at the doctor's office. Those places have heavy-duty air filters which are cleaned more frequently. [Answer] # 1 - **We're icky** There is a hygienic dimension to clothing. As mammals, especially placental mammals, we're always secreting and shedding *something* -- sweat, oil, hair, dead skin, and many other substances that are unnecessary and inadvisable to list. The areas we cover up are notorious for making right messes, and even the more acceptable areas may be suspect due to sweat. This is exacerbated in low or zero-g environments due to the fact that these particles are free to detach from the body, float and get everywhere. The *very best* case scenario is that the whole station will start to smell like old sweat, which probably won't be a problem for people who have been in microgravity long enough for their noses to stop smelling as well. Worst case...well, there's lots of things you really don't want getting on your computer interfaces. Or in your food. It could even be microscopic particles, and those are just yummy. You could bathe and shave *constantly*, but that's a bit of a waste of station resources and you're better off just wearing material that can catch all the gross mammalian materials and wash those in bulk. At the very least, you'd wear something to cover the pubic area and that would narrow the problems down to sweat and stray body or head hairs. Everyone would look like they're at a topless beach party, but it would be enough for the majority of human cultures to consider "clothed". # **2 - Protection** Space is pretty dangerous. Here you are floating in a tin can, far above [ gravitational reference body ]. Anything can happen; your body can be exposed to raw sunlight, gamma radiation (gamma rays from malicious sources can have devastating effects on crew), or even open vacuum. The human body doesn't really care for any of these, and so an advanced bodysuit of some kind would be preferred. Furthermore, navigating a microgravity habitat is a constant gymnastics show. Astronauts launch and throw themselves off surfaces and try to catch bars and top themselves on other surfaces. If you miss, you're likely to collide with something or graze your body on some equipment. Something can poke your belly, scrape against your back or hit you right in the space nads. It's nice to have something to absorb at least some of that impact. # **3 - Utility** Working on a space station requires versatility and high function. You'll need to carry tools and materials with you. To do this you'll need pockets, loops, velcro pads etc. It would also be highly beneficial if you were wearing some kind of harness; you can hook yourself to surfaces, brace yourself into places, and can easily go in and out of exercise equipment. The harness itself could also be a modular chassis for utility attachments, not unlike the H-harness that U.S. Marines wear. Could you get by with just the modular harness and pocket belt? Eehhhh, *maybe* but the mental image at this point is getting pretty fetishistic. You can still go for it, man. It's your world, you're the creator. # **4 - Comfort** I'm not gonna lie, walking around in just a birthday suit can be nice when nobody's around. But the feeling gets old, and it feels way nicer to have something soft and loose over your body. Robe, pajamas and T shirt, night gown, whatever orbits your spacecraft. Space stations aren't exactly known for being soft, warm and cuddly so wearing something to counter that can be a good idea. # **5 - Fashion** Why navigate a space station in your birthday suit when there are *so many other suits to choose from*? Humans have always wanted to express themselves, and there's really no other universal way we do that than in what clothes we wear. It doesn't have to be anything fancy, though anything can happen. Anything from a simple T-shirt with an outdated reference from 2034 to a flashy yet functional station suit could work. How much clothing we decide to wear has varied over the millenia, yet most people from history would have agreed that people who had very little clothing were typically low status. # **6 - Religious views** This one is pretty self-explanatory, isn't it? # **7 - The Powers That Be say "NO"** Your astronauts of the Immediate Future may be progressively-minded, but Earth, that old world, is not. They also happen to be the ones funding your continued operation and survival. Your crew will very probably get to have some downtime where they can wear whatever they want, but in official broadcats and on receiving visitors, it's expected that they dress accordingly. [Answer] **Spacesuits are compulsory** The human body is ill suited for leaving the confines of Earth. Spacesuits serve a variety of necessary functions in order for humans to operate in space like temperature regulation, providing an air supply, protection from solar radiation, etc. Those living or travelling in space long term have to be prepared to enter hard vacuum at any moment to effect repairs or modifications on the external surface of the spacecraft. Even the stripped down "casual wear" astronauts might don when not on shift would have common sense features deemed absolutely necessary like life sign monitoring, communications, distress beacons, etc. Therefore you can go starkers if you want...*under your spacesuit* [Answer] If the future conquest of space follows the example of our recent creation of cyberspace, then advertising dollars will pay for a great deal of the infrastructure that is needed. Streaming coverage of everything extraterrestrial (except private bedrooms) might be a major part of future entertainment television; like reality television only on a grander scale. Perhaps the sponsors of the Titan station are family oriented. [Answer] Don't think anyone else has mentioned this yet: Heat Perhaps not a full on reason for zero tolerance as such, but what about the fact you have to heat/cool a spaceship? Having your occupants in their own bundle of self-generated warmth means you don't have to heat the whole space as high as you would if everyone (or even one) person was nude. (Economical heating reason) You could go as far as to say that some components on board need a cool (maybe sub zero) temperature to function properly and so low temps are a must. Perhaps as a safety feature in case of coolant containment leak everyone needs some sort of thermal protection. [Answer] ## Because the ship is kept at a readiness condition in space And part of that is clothing designed to buy you precious seconds in an emergency. ***Set condition one throughout the ship***. Thanks to *Galactica*, that is the most recognizable form of naval [Material Conditions](https://www.navy.mil/submit/display.asp?story_id=104188). These are measures to render the ship more stable and damage resistant: which hatches to keep closed, which level of readiness the crew should have, etc. Real material conditions in the US Navy are: * X-ray: sitting in safe harbor * Yoke: **underway at peacetime**, at risk of ordinary accident * Zebra: more challenging or risky operations with higher risk of damage Pleasure craft can get away with cruising around at *X-ray* because at sea, there are no micrometeorites. Space is far less forgiving, which forces *everyone* to take Material Conditions seriously. Anyway, one aspect of Material Conditions is personal protective equipment. In space, normal clothing is actually **special clothing**. First, it helps you survive decompression and remain functional long enouch to get to an emergency equipment trunk. It also helps reduce your injury in fire, and other important jobs. You must be in in this garb at *Yoke* or *Zebra*. Yoke is the minimum possible material condition for a space station. This became an absolutely militant requirement after a string of accidents, including the unnecessary loss of the *Intrepid* passenger liner with 3000 souls. Space is astonishingly good at preserving evidence. The key command personnel whose skills were needed to coordinate recovery were all found either frantically trying to put on proper clothing, rushing toward an emergency trunk, or inside an emergency trunk whose door they couldn't close because their hands stopped working. Without appropriate garb, they just ran out of time. The efforts of the rest of the crew were poorly coordinated and inadequate. They determined essential personnel needed to have the proper clothing on at all times. This soon became a problem. First it proved impractical to distinguish "essential" from "non-essential" personnel, with lots of petitions to have ones job declared non-essential, cheating, and cries of unfairness. Second, when people were allowed to be unprepared, saving them distracted damage control crews who needed to focus on saving the ship. They should leave individuals to die, but that's asking too much. So authorities gave up, and said "everyone has to be prepared, always". [Answer] **Religion.** Historically, the most common reason for prescribed garments has been religion. These garments might be obvious to all and so symbolize common membership in the religion (e.g. head coverings). Some garments are not obvious and serve as a reminder of vows to the adherent of the religion. The [Mormon temple garment](https://en.wikipedia.org/wiki/Temple_garment) is one of these. > > A temple garment... is a type of underwear worn by adherents of the > Latter Day Saint movement after they have taken part in the endowment > ceremony. Garments are worn both day and night and are required for > any adult who previously participated in the endowment ceremony to > enter a temple. The undergarments are viewed as a symbolic reminder of > the covenants made in temple ceremonies and are seen as a symbolic > and/or literal source of protection from the evils of the world. > > > Your spacefarers are the member of a new religion - or maybe an old religion or remake of an old religion. It is lonely in space, and wearing the garment reminds spacefarers of their connection to something larger - their relationship with the divine powers of their religion, and with other members of their faith. [Answer] You cannot make such a prohibition because basic sanitation and hygiene requirements require some degree of nudity at different times. See for example [Skylab Shower](https://en.wikipedia.org/wiki/Skylab#Shower). In fact the requirements of space flight and relatively confined quarters essentially require that people engaged in space flights must be comfortable being unclothed at times around each other. Modesty is not worth the mass it costs and mass is the most important thing. Mass used in providing special privacy could be better used providing e.g. additional backup life support or something similar. In an emergency do you want people worried about a ban on nudity or people who will act decisively and immediately ? Nudity should not be an issue for people in this line of work - practically speaking nothing should bother them. If they have to share crude sanitary facilities due to e.g. a breakdown, then that's what is required. No silly restrictions should get in the way of what is practical in space. > > There is no policy on possession of adult materials or even engage in intimate activity, just no nudity strictly! > > > This actually makes no sense. Apart from anything else, no nudity isn't very reasonable when you're allowing intimate adult activity. Put crudely, if they can screw it makes no sense to even *try* and ban nudity. The crew would almost certainly be chosen based on their psychological and cognitive balance as a team, with overlap of skills and the psychological ability to complement and replace each other. These people won't even notice nudity. The idea is deeply flawed, IMO. [Answer] Specific radiation answer, the primary reason: Due to mass constraints, space vessel walls have been designed to provide enough radiation shielding just for electronics and brief human exposure. For any prolonged stays, everybody must wear a radiation protection suit. It's not very heavy, as it is designed to work with and complement the walls. But without it, you will shorten your life by decades, and the more time you are without it, the worse it gets. So taking a bath is no problem, but sleeping without a full body sleeping suit every night is going to be. Once this primary reason is established, and having a suit is this way mandatory, all kinds of other things will get integrated into the system. For example, the air filters can be lighter when everybody is dressed all the time, as mentioned in the other answer. The suits can actually be part of the cleaning system, they are designed to sponge up dirt particles which then get removed when they're washed. Then there's the obivous monitoring of vital signs. Haptic feedback effecitvely giving extra senses, for example feeling of pressure before body actually bumps into a wall, could also be a factor, it could be a required safety measure in addition to the more obvious physical protection of clothes, not so much to protect you, but to protect the space vessel interior from wear (so again it can be made with lighter materials). It won't be long before the space folks will feel *almost* as naked without their special suits, as we feel without our mobile phones today. Except in space it is positive thing, without the mobile phone dependency stigma of today. If you aren't wearing your suit, you are all kinds of rude, almost to the point of being hostile, to everybody around you. It's like walking in someones home with dirty work boots, leaving marks and dirt everywhere. On earth that just makes a mess and scratches the floor, in space it can kill you. [Answer] Perhaps teenagers and/or children are on most if not all missions. This may be a part of a high-school class, a trade-school program, or even a menial job opportunity for teenagers (even space stations might need cooks, janitors, or the like). For the sake of avoiding moral or legal issues with underage individuals being exposed to, or exposing themselves, a zero-tolerance nudity for anyone at all times might make sense. [Answer] Others have mentioned the issues with the human body leaving dead skin, hair, sweat and the like everywhere, but there is actually a great example of this problem on earth: Nudists. Nudists are generally expected to carry a small towel or similar to sit on, because a lack of underwear creates hygiene issues. Also as people get older they tend to leak more. It's somewhat manageable on earth where there are a limited number of places people are likely to sit and they can be cleaned, but even so towels are often mandatory. In space, with low/zero gravity, cramped quarters... [Answer] If you've ever been to space, you'd know that there is no such thing as still air in the kinds of environments humans can function in. Without gravity and weather to ensure the constant mixing of atmospheric gases, pockets of noxious carbon dioxide would quickly envelope the head of anything that breathes. As a result, the environmental systems in micro-gravity habitations need to be constantly forcing air circulation. That ends up with a constant breeze blowing over your skin, which most people find discomforting, and with long-term consequences both to the creature's integument and to the environmental systems that collect off-cast detritus. It's not hard to see how a constant need to cover up because of chronic environmental and health reasons could morph into a social prohibition on nudity. Of course, there's always that one guy.... [Answer] Because space stations get a lot of mold (the ISS does – <https://space.stackexchange.com/questions/2143/where-should-i-look-in-iss-to-find-mouldy-food>), and food is never fresh, and water is recycled. This means sometimes there's nasties in the food or water. This occasionally means people get diarrhoea. Ever since the first station-wide outbreak of **diarrhoea in zero-g**, everyone agreed that keeping your pants on whenever possible was for the best. [Answer] Spacers are an independent bunch and will happily float around with parts flapping in the breeze. Earth governments, in an attempt to maintain control over the spacers who are out of their physical control range outlaw any activity that could be part of a budding "spacer culture". Thus, Earth mandates a number of really inefficient and downright inconvenient methods just to enforce Earth culture on the spacers. Maybe any entertainment watched must contain ads that are used on Earth. Those ads would have nothing that the spacers could get or even use in space but they are part of the attempted enforced culture. Also, new words would have to be approved by Earth (i.e. France). They could have "culture ministers" who travel to make sure that no group behaviors are forming which would lead to independent thoughts. ]

[Question] [ The setting is of 2010. No weird science nor aliens. There's this crime lord who climbed too quickly up the power ladder. He has an uncanny ability to know exactly what everyone within his range (20 kilometer radius) is doing. Anyone who comes into his range is recognized, not by name but he can tell everyone apart without seeing them. The means by which he obtained this ability is unknown (or irrelevant). He is, otherwise a normal human (with common sense). His seeing & hearing ranges are normal. A very skilled assassin is sent to kill him (as skilled as you could imagine within current technology level, no magic). The requirement is only to kill him, by any means, but avoid killing anyone else. The maximum casualties allowed is 10 deaths. **Edit 1** His power range is a sphere. His power only lets him know who does what, instinctively. He can't tell the intention. He won't ever get sensory overload. **Edit 2** For some who are wondering why I won't just quarantine the area then send an army after him: he would see it from 20 kilometers away (maybe more if he has spies or scouts) he would have plenty of time to put on a disguise and slip away in the mass confusion (you're attacking a city after all) and if there's no mass confusion he would just explode some buildings (setup before-hand, it's sensible to have backup plan) to cause confusion and slip away. Why I don't just send assassin to sneak into his building and kill him in his sleep: he's well aware of his vulnerability during unconscious hours and the ability to sneak into any building is overrated in movies. It's a den, of course there will be plenty of elite guards who, once they shoot, only miss half of the times (and there's plenty of them to make up for that). Beside, who said there wasn't something like an automatic turret with facial recognition that shoots anything unfamiliar? Remember, he's sensible. He doesn't have to be a genius, he can hire geniuses any day to design his den. Why I don't rig some beggars and detonate when they got close to him: seriously, beggars have no chance to get close to him and why would he go to places where something like that could happen? When he goes out, he uses his armored vehicles, multiple ones just to confuse people. Again, he's sensible. Why I don't send him an explosive gift: why would he read mails and open gifts by his own hands? He has assistants for that. Explosive phone? He's sensible, why would he want a stupid expensive iPhone for? He would order one, custom made, with highest security, encryption money could buy. Drones: it's his obvious flaws, so it's only sensible to have his building or panic room protected from such. His anti-air should be as good as any warlord. And you don't see many warlords killed by remote controlled drones. I must **emphasize** again that he's sensible. Meaning he won't work alone. He's not a genius but he has money to hire geniuses. He or his consultants would recognize his obvious flaws and should have some countermeasures. The crime lord has been subject to previous assassination attempts and is very cautious. [Answer] Plant an explosive device ahead of time at a location he is going to/under his car/etc. Use cameras to cover the location. Activate it remotely. So long as all the setup is done outside of his perception range then he has no extra defenses compared to any other target. [Answer] ## Do it when he is asleep. Pose as a homeless bum or something and hang around to learn when he is asleep and awake. He's an otherwise ordinary guy, so just use those standard assassin skills, wait until he sleeps, sneak in and take him out, or plant a bomb. [Answer] You need to check-mate him. In chess, each opponent is also omniscient in the sense that they know where all the pieces are and what their possible next moves are. The best chess players are those that can predict all the possible future scenarios and avoid being left without an exit plan. One relevant story that incorporates this component in a certain way is Death Note. One guy has a curious power and the best detective is sent to take him down. The detective has all the pieces in his head, but he only needs concrete proof of what is going on to link them all together. The whole time, they are "fighting" in the open, next to each other. [Answer] ## Brute force There is a difference between knowing someone is going to kill you and being able to stop it. If your assassin is skilled enough, perhaps they can get there and finish the job anyways; they just need to be really, really good at what they do. ## Espionage-like tactics Send someone or something without the obvious intent to kill. Ship in a delivery of poisoned or allergenic food, a gun that fires backward, explosives, or an escort who doesn't realize their lipstick is laced with slow-acting neurotoxin. It may take some time, but you can minimize causalities without risking detection - and look damn cool in the process. ## Sensory overload @SRM has the right idea in the comments: depending on if they can sense everything at once, lure them into a crowded area where everyone has completely different objectives, make it hard to focus on one hostile individual, then finish the job in a nearby cafe bathroom, subway car, etc- somewhere where causalities will be reduced, but there are people relatively close by. [Answer] ## Sniper/Bomb Drone As the title says, a small flying drone equipped with a gun can do the trick, it's improbable he won't be outside for at least a few minutes, so you could snipe him from above. Another way is with a drone with a bomb on it, just reverse the propellers, and drop as fast as possible on him, detonating near his head. A rolling one might work too, but it is a bit more obvious. (Maybe just a kid playing with his toy truck and suddenly boom.) Of course the drone is piloted outside of his range. This is also assuming he can only detect humans. [Answer] # Mechanical view on the problem The problem is akin to the issue of radio silence in the military -- there is a time for secrecy, but when action starts, secrecy gets in the way of action. The idea is to keep secrecy as long as possible. When the action starts, **secrecy is dropped** and the key is to **hit quickly enough and hard enough**, that: 1. The target has no time to avert the threat once it realizes what's going on 2. It cannot recover from the blow. **The problem of your limited-range-omniscient is thus the same as any ordinary target, but just expanded**: there is always a point where a target will *realize* that someone is after them: at the latest (for any ordinary person), at the exact moment when the body is hit. But at that point it is too late and the hit is too hard. Your target has an "outer envelope" of 20 kms. It means that you have to put them in a situation where they cannot react fast enough, once they realize about the threat. The idea of bringing the person into a **booby-trapped area**, all by itself, has a shortcoming, in that it is *slow*. Also, you would have to evacuate anyone who knows about the attempt from a radius of 20 miles around ground zero. It could work, but they are many ways it could fail in such a long time span. Aside of **sensory overload** (@Zxyrra: brilliant idea, which can be used in conjunction!), I guess the simplest way would be to take off the individual from a distance. They are no long-distance rifles that can reach that far (a pumped-up howitzer could, but the damage would be too large and that's explicitly forbidden). So one might perhaps go in the direction of a very fast self-propelled weapon, radio-controlled (or better self-controlled), what we would call today a **drone**. The drone would have to be pretty fast, and be pretty fast to redirect their course, so that the person cannot escape it, no matter what they do. # Combining the solutions into an elaborate trap **Since the art of war is deception** (Sun-Tzu), one would have to attract the target in some place where it would be an easy prey, through some lie. A good way to do that is to **use his sensory ability against him**, by making threats appear all over the place, obscuring the actual source. That **sensory overload** (like movie scenes in a **house of mirrors**) could be used to upset the target and lure them into an open place where it can be taken out in the most unexpected way (e.g. a drone or a bystander). So 1. Trick the person into believing that some place is booby trapped and get them to panic, through the use of sensory overload ("hall of mirrors"). 2. Get the person to "hurry out of there" into an open and empty location. 3. Take the person out with a **fast moving, self-propelled, self-directed weapon**... or get the person to **do something stupid that will inevitably get them shot on sight by a bystander** (e.g. a policeman or security guard)! 4. *Or combine the two*: the person realizes a drone is coming and is drawing a rifle to take it down. Armed guard, not knowing what's going on, yells "drop that weapon!" and finally shoots. Warner Bros. could have written a scenario for a cartoon, with more or less with that kind of formula (with the coyote going mad in a hall of mirrors and finally realizing they are doomed in front of a live artillery shell that keeps rotating so as to always point at them). That's not the only solution to the challenge, but could make for quite a fun and grandiose finale? *Of course, not all of it could be planned beforehand by the assassin. Perhaps they went as far as the drone, and the shot by the policeman was an unexpected twist that saved the day. In real life, things never go exactly as planned and good/bad luck enters in*. [Answer] Send an unintentional "assassin", that has no intent to kill him. The assassin could be a pizza delivery guy, delivering pizza bomb, he never knew anything about the special pizza delivery. For extra sadism, the "assassin" could be his family or close friends, they thought they're giving him a gift for the Holiday season. Little did they realize that you've spent the last few months to socially engineer them to choose a particular gift that you've bobby trapped. Or you can send a hitman that has a regular job, like construction worker or a postman. Hire the hitman for his regular job nearby the crime lord's residence, the hitman must never suspect that he's being hired to do a hit. Get him close enough so that the hitman himself don't come with any intent to kill. At the planned moment, tell the hitman that his hiring was actually a facade and make him an offer he can't refuse, with the condition that he immediately do the hit within an hour, equipments are already provided nearby. [Answer] Smartphonebomb. Build a smartphone, way out of his range. Name it the new iPhone X or Samsung Starshine 7. Let him know this is the state of the art cell phone for the crime lord of the 21 century. It is a must have! Give it to him as some sort of present, e.g. crime of the year. He has some ego, so he will accept it. Because it's golden and with fancy diamonds. Inside this phone is a small portion of explosives, triggered by a certain phone number / SMS. The phone is given to the boss by some innocent bystander how doesn't know about the explosives. Let the boss get used to the phone and use it regularly and at some time, call him, wait until he's at the phone and boom. * Triggered well out of 20km Range. * Casualties: one. [Answer] If he expect his enemies to coply with the Geneva Protocol, then shell the entire area around him with sleeping-gas, go there in a gas mask and stab him with a cheap kitchen knife. Dependent on the crowd-density and the used ordnance, the accidental casualties would be < 10. [Answer] Get a job at whatever liqourstore this guy gets his fancy wine/beer/vodka/whateverthehellcriminalsdrinkthesedays from (he's been getting his liquor here for years so he trusts it and won't have it pre-tasted) A fine rich gentlemen such as himself doesn't have the time to go to a store and get some fancy liquor, so he sends some grunt to pick it up for him. All that is left for your assassin to do is make sure the liquor is in the back of the house. (and hope it's something that can be re-sealed without it looking to suspicious) Poison the liquor, give it to the grunt, and pray to the God of Murder that your crime-lord takes the first sip. [Answer] **Use two (or more) people with extemely specified instructions** He knows the intentions of everybody in a sphere of 20km around him *and* he is a crime lord, which means he is generally surrounded by other criminals (his bodyguard, hired assassins and on). This means that there are a lot of things you can think around him while being ignored (if he or one of his lieutenants hire assassins he will probably rule out as safe intentions like "I will kill X", everytime X is somebody else). If **the real assassin does not know his target until the very last moment** he cannot be alarmed by him (there is nothing wrong with a compound security guard who has been ordered to shoot whoever enters that corridor, right? It's his duty, I just need to stay away from that corridor). You can push this even more if the assassin isn't aware of the lethality of the actions he is to perform (he simply has to press a button whenever somebody enters the room, it has been somebody else to rewire the button from the light to a landmine - and even in that case you can split up the task so, in the end, **nobody knows exactly what's going on, and so it is impossible to detect the outcome of their combined actions from their intentions**). After you set up the situations, you have to drive the target in position and, this time, his power is going to help you. He is bound to have an emergency response procedure for when certain things happen, but you don't need to make them happen, just to be read while thinking about making them happen. The best bet here is something flying since 20Km isn't really a lot in the air and, worse, striking down something over you can still be lethal, so the safest course of action is to hide first and react second. At this point you have your target running straight in to the trap. [Answer] # Build a ninja-robot It's unclear whether his power works on all objects or just on people (and if it worked on everything than that invalidates quite a few answers posted here). So just build a machine without a consciousness and program/remote control it to sneak into his house and kill him. [Answer] ## Railgun If you are looking for a way to kill him and not just fixated on the assassin method then you could look into railguns since they can fire from up to 300km away. The projectiles hit speeds of around 2km/s so it would take 10 seconds to hit your target from 20km away. I'm guessing a railgun attack won't even cross his mind, and since he knows everything in a 20km radius I'm thinking his room would have a big window facing the city because he knows he won't be hit by a sniper. So all you have to do is fire a railgun and hope that he doesn't get up from his seat in the next 10 seconds. However you would need to build or bring a railgun without him or his trusted people knowing. My best bet would be bringing and firing the railgun from a boat (if his house is close to a coast). [Answer] The hypnotized hooker. Even crime lords have needs. A high class escort girl had some hypnotic programming in her subconsiousness, she doesn't know about. She'll seduce him, get him into bed, trigger the programming and the hooker will kill him with an ice pick in her bag. Or place some HMX in her bag, that'll go off, when they go off. [Answer] His power's main weakness is the distance limit. Is he a complete reclusive hermit? If not, there will be places he goes even if only occasionally,which are more than 20km away. Any amount of preparation can be made to kill him in any place more than 20km from where he is at any given time. So if he visits a sick relative or a fellow criminal more than 20km away, if one of his kids (if any) or his mum or some relative is deathly ill, in trouble, or badly hurt, or something else happens that takes him 20km away, your assassin has an easy time of it. **Update to elaborate on this** He can't tell what someone did in the past, only what they are doing now. He can't read intentions, only actions. Very likely, he travels, or has a friend or relative or somewhere he goes more than 20km from home. If needed arrange a traffic accident for his out of town mother, or a serious sports accident for his kid, or just wait till he goes to his favourite hotel or whatever he does for vacations, or buys something from a regular supplier not in the same town. He cannot know what has been done in those remote locations. Plant a lethal device in the place he's enticed, with a wifi based trigger, and a nearby webcam to keep an eye on the scene. Then create your enticement or wait for his arrival, and retreat 20km. When he's visible in the webcam, trigger the device. Nothing will give away the explosive placed under the driveway, the poison spray in the airvent, or whatever else you choose, because at no time is he within 20km of anyone doing any action that would catch his attention. [Answer] If there are few people in the area, you could send a missile with too great a splash range for him to avoid. Otherwise you could use some other inanimate object he can't recognize since he only recognizes people. A remote controlled robot if you're lazy or a trained poison monkey if he doesn't see animals. A flood is a possibility, or a fire. You might even be able to lure him out of wherever he's staying by just doing something extremely unusual repeatedly like throwing a typwriter at a wall repeatedly within his range in the hope he can't stand t=not knowing and comes to check it out out of curiosity. also planting a bomb before he arrives is the obvious choice. [Answer] ## Cell Phone Bomb This is not a science-fiction creation, either; the Israelis used a cell phone bomb to assassinate Hamas bombmaker Yahya Ayyash on January 5, 1996. Shin Bet made up a cell phone that had bugging devices inside it and gave it to Kamil Hamad, who was the uncle of a childhood friend of Ayyash's. Kamil gave the phone to his nephew Osama, knowing that Ayyash sometimes used Osama's cell phone. What Shin Bet didn't tell Kamil Hamad was that in addition to the phone being bugged, there was also a bomb with 15 grams (a little more than a half ounce) of the high explosive RDX inside the phone. When Ayyash used the phone, Shin Bet detonated the bomb and killed him. See the [Wikipedia article about Yahya Ayyash](https://en.wikipedia.org/wiki/Yahya_Ayyash). Also, if you think 15 grams of explosive doesn't sound like very much, here's [a video showing the detonation of 9 grams of RDX](https://www.youtube.com/watch?v=TgosSXNbg8U). Watch it, and imagine a charge 2/3 larger going off right next to someone's head. [Answer] **Just shoot (or stab) him.** Presuming the assassin is unknown to the target, if the target can't tell the intention, all the assassin needs to do is prepare in advance to only do usual stuff inside his range. Once inside, the target will see the assassin "walking" and such. If needed, the assassin can wear disguise (a policeman carrying a gun seen from 20km is the same as 2m). When the assassin is in range, strike as usual. [Answer] Sniper at long range. He knows somebody is pointing a gun in his general direction, but he can't be sure he's the target. Especially if your assassins are like the Weavers in [Wanted](http://www.imdb.com/title/tt0493464/?ref_=fn_al_tt_1). Edit: New idea just popped in. Find somebody utterly incompetent and accident prone. Find a way to assign him as a bodyguard to the crime lord. Wait for results. [Answer] He know people is coming to kill him, **he has no other magic powers to prevent people killing him**, he could hide, but he has no more super powers to run away at super light speed. There are a number of variables that can influence the result. If you know a building is going to explode in 60 seconds, but you are on the top floor and you cannot get out in 60 seconds, your knowledge of the imminent explosion is of no use. * Do the police/military know what is actually the appareance of this villain? If there is a sufficiently large task force seeking for him, a SWAT team or a military squad, he would be forced to escape. **He do not have the powers to escape forever**, nor the "superior smartness" to find original escape routes. At some point he would do a wrong step and get caught/killed. Or he could escape enough to reach a lowly dense populated area so that also "medium area of effect weapons" could be used. The plot become more complex **if the police actually does not know the appareance/identity of the villain**, he could disguise at his will any investigation (he could already know answers to questions police ask to him, or avoid at all investigators by being in the wrong place at the correct time). Again **he could do at anytime a wrong step** (because he is not a crime genius), that lead police first find his identity and then to hunt him. His kind of powers are usefull for any "low-profile" criminal for to a real evil genius. He could also be a perfect gambler in games like Poker because he know if other people really have a good hand or not. [Answer] > > He has an uncanny ability to know exactly what everyone doing in his range > He is otherwise a normal human (with common sense). His seeing & hearing range are normal. > A very skilled assassin is sent to kill him (as skilled as you could imagine within current technology level, no magic). > > > The crime lord can't read minds, so the assassin sets up shop well outside the target radius and hires a dozen guys with some story - they need to wear Google Glasses and accept to be remote controlled through radio earbuds. They can believe that they're pawns in a RPG for the filthy rich; they just need to never break character or they lose a hefty sum for services rendered. Under this guise, the assassin can inspect the whole area and determine where to strike. One way he could do this could be with another remote-controlled squad posing as a TV news team, or something like that. Unbeknownst to everybody inside the crime lord's radius, the TV cameras also contain powerful remote-controlled rifles. One of the guys gets instructed to get a good head shot of the crime lord while he's crossing the street, and... [Answer] Several approaches: **SUICIDE BOMBER** arm him well out of range and just have him drive to the mob boss's location and have him go about a routine until he's within range of the boss. If you don't care about dead civilians, this is a sure-fire way to get him. **REMOTE DRONE** Have a drone operated beyond his range. Kill him when in range. Use a small drone with a single-shot to keep the drone small and hard to detect, giving the added bonus of a stealth weapon so that normal means of detection are less useful as well. [Answer] Killing him in his sleep is one good, clean but perhaps an anti-climactic end to such an enemy. ## TLDR: **The information he gathers from his power will inform him of where to go, you just have to read how he will react to a situation and then create that situation and be waiting for him.** Another possibility lies in his ability know actions, not intentions. Your assassin would need an accomplice. The assassin enters the 20km radius and carries out rather mundane tasks regularly - visiting a shopping area for example. One day the accomplice enters and does something which seems suspicious, he rents a hotel room near by, prepares a bomb, loads some smuggled guns - all thing that draw the crime lord's attention. The exact workings of the power aren't too clear to me but some how get across to the crime lord that this man with the bomb has no qualms about killing his men but doesn't want too many innocent people to die. The crime lord will have had attempts before and, as before, he will send some of his men to get rid of this man. To make the accomplice think twice he will relocate somewhere with innocent civilians (you can choose any public place you like as long as a bomb can't be used an a clear shot couldn't be got). Your assassin also visits that public place and in a crowd walking along he will seem no different until he is close enough for the power not to make a difference. If your assassin is armed it must be with something day to day, no knives or guns. He has to use his environment most likely. The exact details depend on the setting you choose but I thought this was perhaps better for story-telling. [Answer] Use two people. The first poses as a repairman, painter, electrician or street cleaner, and hangs around on the street with a view of the crime lords entrance. The second guy comes a bit later, driving up, parking his car near the bosses entrance (driveway, garage, etc) and gets out and goes shopping or trivial activities nearby. Nothing suspicious yet. Now when the boss moves close to the parked car, the first guy reaches into his pocket and presses the button on the detonator. Car bomb explodes dramatically, taking out the boss. If you think the triggerman glancing at the boss will be detected, have several different triggermen wandering around, each looking less often. [Answer] Poisoning might work. Poison the food outside of his realm of cognizance and then bring it in. He can't sense intention, so he won't have any reason to suspect the food is non-standard. A slow-acting toxin would be sufficient to avoid a taste-tester detecting the poison. [Answer] So many "Sensory Overload" fails! Since the person CANNOT, EVER! Become sensory overloaded.. Use sensory deprivation..! 1. Stop all food going to him. This you can actually do with the intent of him starving to death.. Because he can NOT read a persons intention(s). 2. He sleeps. In middle of night, send and EM-pulse so that every electrical device is shorted out. He cannot see, he cannot hear, he cannot smell nor feel or taste. Now all you need is some imagination. Cause your last stage is to just throw, like non-working flashlights. Not to kill him. But confuse him.. You cannot now when you actually throws in a pre-made bomb. And then, to late.. 3. Use him against himself. There are ALWAYS extremely positive things that if given to the wrong person, would completely derail this persons life. Remember, everything is in the eye of the beholder, so! Do something that this person cannot handle mentally. Your intentions are good from start to finish! It will be himself that will end his own life because he cannot live with; Guilt, shame, beliefs, etc. Everyone has such weak spots.. 4. There is extremely easy to make a poison, out of very ordinary products (which I won't list nor explain, of course..). But this travels through mold spores. They cause Cancer within a year, and is virtually untraceable due to the lenght of the death. 5. Discipline. Extreme mental discipline. (If you cannot think out the rest for your selfs, well, then I guess you have to riddles.. ;) ) Fun, but a little "easy", thought-experiment! =) BR, Don't assassinate people, please. [Answer] Speed kills. His knowledge radius is 20 km. Knowing something and doing something about it are two different things. By involving speed, you let him determine there's a problem, but don't give him time to avoid it. More dramatic tension if he knows what's coming and it's increasingly inevitable. Example: A modern passenger airplane can go perhaps 900 kph, which is 15 km/min. An approaching plane on an intercepting vector can then further shorten that interval resulting in an approach speed up to double (if head-to-head). At a combined 30 km/min, the target would have about 40 seconds to respond to a threat, while in a closed space not under his direct control. A Gulfstream 650 approaches 1000 kph, so there'd be even less time to react on a faster private plane (that every crime lord who is anyone would simply *have* to have). To minimize casualties, the pilot (or a small skeleton crew) on the target's flight could know what's coming and swap auto-pilot/bio-break time for an escape just prior to danger arriving. In all cases (mine and others), he can only tell what people are *doing*, not what they're *intending*. It seems like anyone who can behave normally until they get close could be undetected enough to do the deed. That's what the original Assassin cult did. Add in a diversion (or a lot of them) to occupy his attention, and you can get even closer. "the slow blade penetrates the shield" - Frank Herbert, *Dune* Overall, it sounds pretty easy to get him, relatively speaking, as long as you don't act squirrelly. The tough thing is getting in and back out safely. Suicide Mission assumption (like original Assassins) solves a lot of problems. The creativity could be in making something that isn't normally considered a weapon into a weapon - a pub dart (or a Jart), a baseball (or a bat), a beer bottle (broken), a steamroller (suddenly veering into his car), etc. - to get it close enough to do damage without causing alarm. [Answer] Hire a semi-omniscient assassin. Preferably one with a wider effective range than the target. If one semi-omniscient being can exist there, so can another. Or, plant lots of little bombs, possibly car bombs, around streets he has to walk/drive down eventually. They have cameras in them, linking back to your operatives over 20km away. Wait for him to walk past a camera, then detonate the bomb. Or, use a long-range telescope from a high vantage point, just over 20km away. It has to be a high setting, to counteract the curvature of the earth. From ground level, the horizon is normally around 5km away. The vantage point would have to be 100ft off ground level (or higher), for a 20km view. This assumes we're on Earth. Other planets would have difference ground curvature, and thus different horizon calculations. Wait for him to emerge via your telescope, then use a long-range near-instantaneous weapon to kill/disable/blind him, maybe a laser. Then take out the area around him with a slower long-range weapon, maybe a missile. [Answer] Use a two part poison agent. The news today gave me an idea for this. A two part poison, something that kills only if two chemical agents are injected. Take the first agent and add it to a thousand dollar bottle of brandy. Send it to him as a gift. All his tasters can try it, the bottle is harmless. Once he has had time to drink some move on to phase 2. Pick a place you know he will remotely be and set up a large number of containers with chemical 2. Ween he is in the area release the chemical. You will get a lot of people but again harmless. Your target, and maybe his food tester that cane with him are dead. [Answer] This is from RED2. Since he is a Crime Lord, he must give out assassination orders too. He must hire people too, and in doing so, he has to share details of the people he wants out. Assuming, he has full trust on his power of Perception, his Intuition on full regalia mode and that the person hired to carry out the job has to pass through This Crime Lord. SO, * create an online threat to Him * When he puts out the Word, get hired [because of your level of skill] * Origami a 'kunai' out of the photo of the soon-to-be-dead. Puncture his jugular artery in the throat ending him but finish the job you were hired to do. He knows you are an assassin, but his hindrance is that he cannot find out each person's intention {stone cold assassin killer}. -:) ]

[Question] [ **This question already has answers here**: [How to Defeat a Precognitive Warrior? [closed]](/questions/10939/how-to-defeat-a-precognitive-warrior) (27 answers) Closed 7 years ago. The community reviewed whether to reopen this question last month and left it closed: > > Original close reason(s) were not resolved > > > The US government is desperate to kill the superhuman rebel leader, but the man is surrounded by "precogs". They can see any attempt on his life before it happens. What plan will the government form to assassinate the rebel leader without alerting the precogs? Note: usually precogs only see about two days in the future and only things that happened to them or to someone that they are closely connected to (e.g. their family and close friends). Also note: If whatever is coming in the future is particular traumatizing or otherwise life-changing to the precog (such as the precog's death, for example), they'll be able to see it coming up to a week before. [Answer] Your strategy will heavily depend of the precogs exact capacity, here are some tactics that can even be combined for efficiency: ## Information saturation You render the precogs useless by saturating them with information and hope some of you attempts will succeed. This means preparing dozens of assassination attempts on the target but also on precogs themselves, their family, their dog, their relationships, so that they are overwhelmed by strong precognitions and will not be able to analyze all of them. Non-targeted operations like bombing may also overload the precogs (depending how they see/react to the future); ## Information hidden over time In short: delay death. Some diseases can be inoculated but cause death only after some time. Some poisons have a cumulative effect. Some substances can also make you react to other that are innocuous usually (like alcohol). I suppose precogs will be attracted by "strong" physical or emotional events, so this seems an efficient option. If progressive death is not an option, two steps can be enough, like trapping the target in a limited geographical location (a building) doomed to destruction in a few days without any possible escape, or inject a micro-bomb that will denotate after days, or completely randomly (depending on how precog effectively perceive things). ## Information hidden Basically : assassinate in the dark. This depend "how" precogs see the future, but they probably receive a projection based on their usual senses. If the killing occurs in the dark and in silence, they may be impaired to detect it. It they sense emotions, assassinate without pain, with a sleeping target, etc. ## Manipulation : reaction makes the kill *Use* the precogs to trigger a reaction that will lead to the killing. This is great manipulation (and can make a good plot) and a need to plan everything ahead. The precogs will see the death coming, but without any way to escape it. [Answer] You poison him using small amounts of drugs that accumulate over time. Basically, slip food laced with [insert some toxin that accumulates over time and requires > 1 week to kill with here] - the precogs won't see anything special, as they'll just see him eating/drinking normally. By the time they see him die, it'll be too late to figure out where he came from - they may see that he dies from poison, but they may not be able to figure out what kind it is just by using the symptoms. Thanks to Falco for this; you can put radioactive material (For example, polonium-210) in small amounts in something he consumes, causing it to accumulate in the bloodstream, resulting in his eventual death. Perhaps try Rabies, as Aron has suggested. [Answer] They can only see the actual attempt on his life? Arrest him, wait three days then assassinate him. [Answer] You may want to watch the film [Minority Report](https://en.wikipedia.org/wiki/Minority_Report_(film)) for one way of doing this. If you have two identically-dressed assassins in the same place at the same time, there's no way for the precogs (or those interpreting the precogs' visions) to tell them apart. So the security apparatus springs into action for the first one, but leaves the way clear for the second one because they don't know there are two of them. (AKA "the second mouse gets the cheese, the first mouse gets the trap".) [Answer] **Make the thing that kills the target the *response* to an event that will seem to be the cause of death. In short, work with multi-layered threats.** To assassinate the rebel leader, you will have to find an action you can perform that is potentially lethal to the target, but to which his/her guards' response is set in stone in advance. An example would be if the leader always has a nearby helicopter on standby to flee with. You would set up snipers to target the leader, making a real attempt to kill them, but to also have their helicopter rigged with explosives and to have someone standing by with an anti-air missile in case the explosives are found in time and a different type of missile in case the guards suddenly decide to move your target on foot. Add enough layers and the precogs will be unable to prevent every layer in time, if they even have a vision that covers it. [Answer] I like the poison ideas but I might suggest a variation to take advantage of the precogs being ultra-sensitive to their own deaths or attacks on themselves. So, the precogs see an event and then their own changes in behavior can avert it. Take advantage of this. Commit to dosing the superhuman rebel leader with a drug which causes highly violent/psychotic/erratic behavior, say 8 days in the future unless the surveillance teams notice a change in behavior of the precogs. The precogs start getting visions of the superhuman rebel leader turning on them and murdering them and their families in a violent rage. They start getting nervous and jittery as it gets close to murder-day and the surveillance teams report this. The drugging plan is cancelled(temporarily). The next day you again commit to drugging him, again the precogs start getting visions of him murdering them and their families in a psychotic rage. Repeat until the precogs either flee from him, start doubting their abilities or kill him first to save themselves. Months of visions of their dear leader killing all around him are likely to take their toll. [Answer] ## **Delegitimize the precogs** Implicit in the OP is that the rebel leader implicitly trusts the precogs. Whatever they say to do, he will do in regards to his personal safety. Depending on how the precognition works, exploits in that mechanism could be found to provide different, hopefully conflicting information to the precogs. If this kind of conflicting information goes on long enough, the leader's trust of the precogs may wain just enough to pull off a successful assassination. ## **Plant a new Precog** Find a way to discredit one of the precogs sufficiently that the leader ejects them. Plant a new precog with loyalties to the government. Formulate an attack on the leader based on the expected interactions between the leader and the precog's personality. Subtle misinformation by the royalist precog may be enough to create an opportunity. ## **Drive the Precogs insane** If the resources of the government permit it, keep up a continuous stream of assassination attempts. Find a highly violent psychopath to invent a thousand ways to kill the rebel leader, then start planning the worst of these. The intent to kill should be enough to inject the images of that assassination approach into the precogs mind. Assuming the precogs are otherwise normal human beings, constant exposure to imagery like that will take its toll leading either to the precog's retirement or increasing ineffectiveness due to PTSD. Without the precogs or with unreliable precogs, the rebel leader becomes like other men again. ## **Combinatorial Explosion of Possible Assassination Attempts** Most models of the future account for the possibility of different outcomes to an event (which I'm going to call "event forking"). The future looks like a giant branching set of paths. Defending against a single assassination attempt is easy enough, just don't be there. Defending against two attempts is harder. Defending three or more simultaneous attempts is even harder. For example, if the rebel stays in his base, he will be killed by a bombing attack. But if he goes out of his base then his own troops will kill him or a sniper will get him. Stay or go, damned either way. ## **The government gets their own Precogs** If the government can get their hands on their own precogs then the playfield is leveled. The effect of this is to see which side can see farther out or master the complexities of all possible futures. [Answer] What exactly can the precogs in your setting see, and what does it say about your setting? How does averting precognitions work? * Imagine that the rebels are hiding in a cave and a [stalactite](https://commons.wikimedia.org/wiki/File:Labeled_speleothems.jpg) falls from the ceiling, potentially hitting the leader. Can the precogs tell? How early? Do they sense the slowly developing cracks and extrapolate from there? * If they can detect stuff falling from the ceiling, how about a trap like the [Schroedinger's Cat](https://en.wikipedia.org/wiki/Schr%C3%B6dinger's_cat) thought experiment? How much warning would they get? Can the precogs beat quantum mechanics? You said [magic](/questions/tagged/magic "show questions tagged 'magic'") and [superpowers](/questions/tagged/superpowers "show questions tagged 'superpowers'"), after all. The next option would be classic [cordon and search](https://en.wikipedia.org/wiki/Cordon_and_search) operations. * Even if the precogs know that the search is coming, there is a cordon in place. Trying to avoid the cordon before it goes up requires the rebels to move quickly, with increased risk of running into a roadblock. * The government could go after communications and supporters. They tap the transmission whenever the smart TV in the living room [uploads voice recognition data](http://www.theguardian.com/technology/2015/feb/19/samsung-smart-tvs-send-unencrypted-voice-recognition-data-across-internet). They track the movement of [every car](https://en.wikipedia.org/wiki/Automatic_number_plate_recognition), every [smartphone](https://en.wikipedia.org/wiki/Cellphone_surveillance). Their routine checkpoints assume that any traveller without a smartphone is no genuine business traveller, and no others are allowed to move. Of course that would be very much a dystopia, but you were talking about a superhuman rebellion. Merely human terrorists caused the real-world US to ditch constitutional principles in the name of security. [Answer] As your precogs can only see 2 days into the future, it should be possible to maneuver your target into an inescapable situation where his death is the only outcome and there is no way of avoiding it. As long as your precogs operate in a branching possibilities manner, as long as you can guarantee almost every branch from a certain situation leads to death, you win. *For example: Ensure your target ends up on a boat in the middle of the ocean. Ensure that the lifeboats are sabotaged and then rig the ship to both sink and explode -- two or more days after he boards it. Now your precogs will see the ship sink/explode but there is no option for your target except to jumps overboard and drown/die of exposure, die in the explosion or get pulled down with the ship. There are probably still avenues of escape in this example, but with enough preparation you could close those off as well.* [Answer] We use a precog of our own to create a logical paradox. Equip two snipers. Let's call them Sniper-A and Sniper-B. Sniper-A is a precog. Sniper-A is ordered to assassinate the target on day 1 only if he foresees that the target will not be killed on day 2. Sniper-B is ordered to assassinate the target on day 2 only if the target was not killed on day 1. If the guards foresee an assassination attempt on day 1 and prevent it, Sniper-B will make the kill on day 2. If they foresee an assassination attempt on day 2 and prevent it, Sniper-A will make the kill on day 1. Either way they will not be able to stop the attack. If the guards prevent the assassination on day 1, it will be carried out on day 2. In this case the assassination on day 1 will never be attempted and the guards cannot foresee it! The same argument applies the other way round. The concept of precogs allows the two snipers form a logical paradox. Because of this, ordinary logical reasoning will never really get you one right answer about what will happen. However in a universe where you are fighting against precogs, creating such logical paradoxes is almost certain to ruin their day! [Answer] ### How about if he is killed with an unlikely event? The precogs will most likely see the most probable future out of several futures which might happen. And each vision can change on the behaviour of any oracle. So send an assassin, which goes into position each day to kill the leader, but only kills him he throws a `6` on a die. Because the results of this die throw could probably be seen as a fixed future, he will throw the die at a certain time, depending on involuntary behaviour of the pre-cogs. For example he throws the die when a certain pre-cog sneezes, or scratches his nose, or frowns. Then depending on the actions of the pre-cog he will throw the die at another time and in a slightly different angle and get another result. So every thought the pre-cog has will change the die result and change the future. This will leave only one stable future for the day: The most likely future that he doesn't roll a `6` and doesn't kill the leader. This will be the same for each day, until luck strikes and the assassin kills the leader. And it will be very likely that the leader will die somewhere within one week. But even if they could see a week in advance and see that he is dead, they can not see how he was killed, because each individual time-path (killed on Monday, killed on Tuesday, killed on Wednesday...) individually is quite unlikely to happen (only 1/6 chance). [Answer] Have two assassination attempts; one immediate, and one put in motion well in advance of the the immediate one. [EDIT] This does rely on a literal interpretation of the following; > > usually precogs only see about two days in the future and only things > that happened to them or to someone that they are closely connected to > > > Suppose you know that the rebel leader will be in an office building/shopping mall at a specific time. You make plans trigger the fire alarm and kill them at the building's fire evacuation point. The precogs will see it, warn the leader, who will logically stay *the hell where they are* during the alarm. All is going as planned. Now you plant a bomb where the leader will be - or rather - you planted a timed bomb there a **fortnight** ago. Well beyond the horizon of the precogs' ability to anticipate. The logic for this goes like such; the fire alarm poses no direct threat to the leader, nor does going to the evacuation point. There are many things that would influence the leader's actions, and most of these would slip past the precogs' attention. Mundane things like what the leader reads in the morning paper, or the weather report on the nightly news. If a fire alarm is triggered, but no assassin is present, then the leader is unharmed, and no more inconvenienced than any other person in the building. They survive the bomb because the normal, sensible, behaviour saves them. Adding the assassin to the mix provokes a precog response: a response that actually causes the assassination. [EDIT] Witnessing an explosion that doesn't harm you shouldn't be perceived by the precog bodyguards. Also, the bomb isn't the cause of the fire alarm, so there's an extra layer of disconnection between the two that helps conceal it from the precogs. [Answer] I see a flaw in the logic of the question. Just because he can see the attempt coming, does not mean he can avoid it. If you know where he is, and can track his transportation, simply keep the pressure on him until he is driven to ground. Once he is cornered, it doesn't matter if he can see that his executioners will be storming the compound. If you absolutely must have Precogs = Safety, then continuously target all of the Precogs. Even if they are continuously able to avoid their own assassinations, that will seriously disrupt their ability to inform the leader of any attempts on his life. [Answer] Hire a good assassin. On occasion when trying to teach fencing, I have told my opponent what I am going to do, where I will hit them and what they should do about it. Then I hit them until they get the parry timing right. If your opponent is faster and wiser than you, then simply knowing exactly what they are planning is not sufficient to protect you. [Answer] **Having Pre-cogs of your own plan the assassination as well as a parallel plan by non pre-cogs** I'm assuming that if a pre-cog were to plan the mission, then not only would the rebel pre-cogs 'see' the attempt and move to counter it, but surely the government pre-cogs would be able to see the counters, and react accordingly. This would effectively lock both sets of pre-cogs in a never ending cycle of move - counter move until the Government pre-cogs stopped planning (since they initiated it and the defenders are reactive rather than proactive). This clears the way for the normal humans to complete the mission. In Brandon Sandersons Mistborn trilogy, the 'magic' relies on burning metals. One metal in particular **Atium** allows you to see, process and then act against attacks as if you were a god. The only way to stop this is by burning Atium as well (or Electrum) as it shows ghost images of all the possible moves. <http://mistborn.wikia.com/wiki/Atium> [Answer] A truly diabolical plan would be to place an attack on all the families of the precogs. Force them to deal with protecting their families and loved ones (which might trigger as much as a week out. Force their attention away from the leader. Have a dedicated team for each family, that dogs their steps for a whole week. Any of the family that survives the week, lives. As the available precogs diminish it reduces the level of prevention. Then host an all out assault on the compound, tasering EVERYONE into unconsciousness. By not killing anyone on the compound it will reduce the feedback to the precogs. Then capture those deemed needed, including the leader. At that point, once he is in custody he can predict his death, and not do anything about it. [Answer] Another option is to outstrip their decision making time. Set up an assassin that uses a quantum random number generator to decide if the mission is a go or not. The assassin sets up an attempt daily. The attempt has 3-5 seconds from decision to death. They look at the random number generator, and if it meets criteria, then they execute him. If not, they tear down the attempt and try again tomorrow. The quantum random number generator cannot be predicted by the precogs. They will know only once the decision is actually made, and they'll only have 3-5 seconds to stop the assassination. As long as you choose methods that will work in that time frame, and verify that the precogs can't react that fast, then they will only see this future at the moment the quantum number generator is stopped and observed by the assassin, and by then it'll be too late. Until that time, they will only be seeing the future as it would occur if the quantum random number generator were never observed. It's a practical application of Schrödinger's cat. [Answer] Being able to foresee something and being able to avoid it are different things. This is the time travel paradox problem in different costume, and all the same answers may apply. Maybe the future that is seen is the only future possible. Maybe it isn't but the universe has some inertia and it's incredibly hard to keep what was seen from happening. Maybe that future happens *because* you attempted to avoid it based on the prophecy. Maybe the prophet can't get every possible detail right and misreads the prediction. Maybe saving this person would cause worse problems later. See also Dune's description of how hard it can be to find a path to a desired outcome through a sea of alternatives. See also Minority Report's observation that even with multiple seers they can get it wrong. [Answer] Use the precogs as the assassins. This can be done with bribery or extortion, etc. I'm assuming the precogs are still human and still have human flaws like greed or family attachments or self-preservation. You can play up on these and bribe or threaten enough of the precogs to either get them to cooperate, disagree with each other to the point the leader can't trust them, or be removed from the leader's service. All of these cases improve your chances of an assassination attempt. It is a costly endeavor, but so is hiring a good assassin, and you have the financial power of a government at your disposal. [Answer] Surround the leader with troops. Plan to assassinate the leader / anyone else in your way a week later, so they can't run before your troops arrive. Kill him when he tries to run. This will happen the day your troops arrive, so they don't even have to bother waiting. [Answer] There is one way to defeat a precog: You narrow the decision window until it is too small to react to. Simple example. Find somewhere that your target goes to every day, that is in range of a sniper shot. Go out there with your rifle, line up the shot, then roll a pair of dice: On a 12, you shoot, otherwise you go home and come back again the next day to try again. This assumes that the precogs cannot forsee the outcome of your dice roll - you might need to use a more sophisticated random number generator instead, but in any case it does rely on there being *something* that cannot be predicted. If everything can be perfectly predicted, then it means either free will does not exist, or there is something special about humans. In the first case, don't bother trying - there's nothing you can do about anything anyway. In the second case, you have your random number generator. Instead of rolling dice, call a random phonenumber, and pull the trigger if the first word they say is "bonjour" instead of "hello". Or something similar, either way you've introduced two random variables: what number you dial, and what they say. [Answer] Plan and execute a simultaneous series of missions to attack/destroy a civilian/neutral targets guaranteed to contain friends and family of the pre cogs. Let the only order that would countermand the attack being the public suicide of the rebel leader. Trust to his own virtuous nature to take care of the rest of the problem for you. [Answer] Create a fake death scenario which drives him into the 'real' one unavoidably. The idea is the second one isn't possible, until the leader has made some choice in response to the first threat. Both threats must be close enough time wise to prevent the precogs acting to stop it. A poison, with an antidote which then kills you for example. The antidote can be slow acting, maybe required to be taken for the rest of your life. However prolonged taking of said antidote is actually poisonous too. Think of cancer, we treat it with chemotherapy, which in fact is killing you also, just not as quickly as cancer will kill you. Something that works in a similar way if what is needed. [Answer] As for what I would suggest. Things can only consistently work if the precognition is limited. Particularly to their point of view or one close. How do you keep them from knowing that their ability is going to be used against them? I would engineer a situation where the leader actually gets saved but the saving process puts him in an longer road to a definite capture. They may be able to foresee their own deaths, but if the leader is saved this won't necessarily matter to the same degree. If its hard to recognize a precog situation or tell how they really will play out or they take time to experience, you could attempt to "spam" their mental inboxes, especially with someone on the inside to monitor things. The more work they have to do the harder it will be to do it. Superhumans are still human. [Answer] Isolate him up in a room (or container, even coffin) with enough breathing air, but no food and water. Cheap, effective. Use a bomb that arms up after three days. [Answer] Actually, the simplest solution is to hire some anti-precog psykers ... Either plant false visions or fog up the future so they can't see it coming. You might have to fog up a few weeks or months ahead, as they'll likely go on alert as soon as they realize that they are under mental attack... but if you keep doing eventually they'll get lax when no assassination attempt occurs, and then **BOOM**. ]

[Question] [ The Galactic Emperor is making a new palace. He has one problem: he can't think of an expensive enough material to make it out of! At first he considered gold or silver, but those are common materials. There would probably exist enough naturally occurring gold on one planet to build the palace. He can't stand the thought of someone thinking he's cheap! He wants something no presumptuous planetary governor could afford to replicate. What's the most opulent material he can make his new palace out of? Some ground rules: * All suggestions must be a real material. * The substance must be safe enough that people can enter the palace for bragging-tours. (See allowances.) * The substance must be stable enough to leave for long periods of time as part of the building. * Being a building material, it must be a solid at room temperature. For practicality, the Emperor will make a few allowances: * It's okay if he must put a layer of clear durable plastic over everything, preventing direct human touch with this substance. (But bonus if that isn't needed.) The plastic doesn't block radiation or explosions or such, though. * He'll allow structural beams to reinforce the material if it's too weak. This is a sci-fi setting with many thousands of systems under the Emperor's control. They can use extensive fleets and industrial centers to gather and prepare the material. What is the most costly material he can make his palace out of? [Answer] ## Curium-247 Curium 247 is by far one of the most stable man-made elements with a half-life of 15.6 million years. It emits very small amounts of alpha radiation, but alpha radiation is mostly harmless since it lacks the penetration power to bypass human skin. A porous transparent coating as allowed by the OP may be recommended in commonly used areas just to be on the safe side though since it would be quite toxic if accidentally ingested and to minimize any long term exposure risks for the people who actually live there. The thing that makes it so priceless is that it has no known natural form. It is only produced as a byproduct of the radioactive decay of Californium-251. In today's market, it is literally priceless because Californium-251 costs 27 million USD/gram (12.25 billion USD/lb) and has a half life of 898 years; so, the mass production of Curium-247 requires the mass production of Californium-251. Let's say your emperor wants to have enough Curium-247 to make a single brick 10 years from now, he will first need to synthesize about 90 bricks of Californium-251... So if we had to put a price tag on it, Curium-247 would probably go for about 2.43 billion USD/gram (1.10 trillion USD/lb) in today's market. This is about 10x cheaper than antimatter by weight, but it is so dense that it is going to be much more expensive per volume than any anti-matter that we can produce and store today; so, holding the annual GPD of Japan in Curium-247 would look something like this: [](https://i.stack.imgur.com/izZZG.png) Now, your average home weights about 1342 kg/m² (275 lb/ft²), but again Curium-247 is VERY dense so a palace made out of the stuff would weigh a lot more. I've got to make some assumptions here but for the sake of argument, let's say that such a pallice would probably be closer to 4880 kg/m² (1000 lb/ft²) of floor space. Now let's assume your size is about the same as history's largest palace, Weiyang, and give it a floor area of about 10,817,819 m² (116,442,045 ft²). That gives you a palace that is made out of roughly 52.8 billion kg (116.4 billion lb) of Curium for a total material cost of about: 128 Sextillion dollars, or in other words, **the entire annual GDP of about 3.5 million Earth like worlds** ... since your poor emperor only rules in the thousands of worlds, this will probably actually be way out of his price range. He may in fact be forced to settle for Curium plating, or a Curium facade. Not only would this help keep the palace in his price range, but also fix any possible radiation issues since all the inner walls could be made of things that block all of the alpha-radiation from getting in. [Answer] **A piece of history** The problem is that any material could devalue or increase in value. That makes the building susceptible to become less valuable over time. What you need is something that is expensive not just for its value as a resource. Make it valuable for its history. There's two ways to look at this. One is using relics and old buildings with history to build your palace. These have historic value and likely will increase in value over time. The cost of moving whole buildings like the Eiffel tower, Pyramids and the Acropolis for example, together with maintaining them, will both be more expensive and more impressive than making your palace from one expensive material. Of course if the roof of a temple is missing you'll fix it with an expensive and impressive material to make it liveable if needed, while keeping the temple intact. Another advantage of using historical buildings is that it's also hard to copy. Even the very idea might become impossible if the emperor puts down laws after he did it (or ignored it for himself). The second is *making* history. Somehow extract resources directly from the sun, or the furthest comet ever found, or drill deep into the core of the Earth and extract from there. Dangerous and difficult to obtain resources will have that extra bit of history. *That* is what makes it expensive. Iron isn't impressive, but when it's iron gotten from the strata of Neptune it'll speak more to your imagination. The value is then not the value of the simple resource, but of the perceived value. Alternatively you make history by using the latest expensive technology to build your palace, making history there as well. The latest screen technology to furnish a whole room. Build a wellness centre where supercomputers are used for the structure and their heat for the saunas. Meanwhile you're contributing valuable calculations for science. Finally you can also make it expensive as it's close to impossible to make. There have been real suggestions to make a mountain in the Netherlands. It would be impressive, unique and is already terribly expensive to create. If it was done, it would raise its value just by existing and being the only one. So make something on the edge of possibility and imagination. [Answer] **Materials are irrelevant** ## What matters is craftsmanship. On a galactic scale, all materials that exist are common. Theoretically all skills are also common, but getting the craftsman for hand carved oak beams is still expensive. As are hand embroidered tapestries on the walls, hand made stained glass windows (these are always expensive regardless), elaborately carved pillars and friezes, and painted ceilings. Merely coating everything in expensive materials to impress the masses will barely be noticed, but elaborate hand crafting will always do the trick. We make passing reference to some guy who gold plated his boat or ferrari, and then he's forgotten, but the ceiling of the Sistine Chapel remains unmatched 500 years later. [Answer] ### MicroSD cards filled with legitimately purchased Music, Software, Movies, etc from your entire empire's history Superglued together into 1 cubic meter blocks, these make a great building material! Can be cut and shaped using conventional tools. * MicroSD cards are 1.65 × $10^{-7}$ cubic metres. * Costs \$670 for a 1tb card. * A good movie compresses to about 700mb, and costs about \$20 at my local store. * Can fit 1462 movies on a microSD card. \$29240 for the content. * \$29910 for 1.65 × $10^{-7}$ cubic meters * \$181,272,727,273 per cubic meter. Using [Palace of the Parliment (in Romania)](https://en.wikipedia.org/wiki/Palace_of_the_Parliament) as the template, you're looking at \$$4.6224545 \* 10^{17}$ dollars for the cost of the palace. With the [Value of Earth](https://en.wikipedia.org/wiki/Value_of_Earth) calculated at approximate \$$1.25 \* 10^{14}$, your palace will be more valuable than 3000 Earths. This has additional cultural value, it's the collective historical works of your society. And its good for your economy - every artist has a guaranteed album sale! [Answer] # Size Matters The palace is a planet. One entire planet. To arrive you have to dock with the Official Arrival Space Station. Landing on the surface is strictly forbidden. The Space Station is the top of a Space Elevator, meaning it is stationary over a point on the surface. The reach the Elevator, you must walk across a big room with a glass ceiling giving a perfect view of the planet above. (The Station is a counterweight to the Elevator, meaning it is higher than a stable geostationary orbit. This gives a pseudogravity *away* from the planet) Looking up, you see... a portrait of the Emperor. The main continent has been reshaped into the Emperors famous profile and every piece of ground has been covered with a building of the right color to make up this portrait. Taking the Elevator to the surface means travelling into this portrait. The Emperor looms bigger and bigger until they become everything. The planet was chosen mainly because it has no cloud cover. No cloud is allowed to shadow the Emperor. This also means that it has no native biosphere. Every piece of food eaten on this planet is imported. On the opposite side of the planet is a continent with all the necessary industry, and a *much* bigger Elevator for freight. [Answer] # It's not the materials It's the location. Most of the ISS is made of things readily available on Earth; Yet it was so expensive to build because of its privileged location (and harsh conditions). Having a palace in a low orbit over Sagittarius A\* would be costly due to the absurd amount of ∆v required to reach it. Might have to sacrifice a few stars for a round trip from or to Earth. However it would put you close to the greatest power sources in the Milky Way, and would give you a view and a passage to the rest of the whole galaxy. The relativity effects would also mean that the Emperor would live for many human lifetimes, making him practically immortal. [Answer] **Unobtanium** Any material the architects can come up with can be outdone. So, the real material should be shrouded in mystery. Covering it in plastic would help to deepen this mystery. Regular people and scientists would ponder about the nature of this unobtanium, but they would never have a clue. All their guesses would be lazily dismissed by the palace staff: "Gold? You must be joking. No, it's much more costly than that." "Diamonds? No way. It's rarer than that." Anyone trying to pick off a piece of the material should be put to death to dissuade further investigation. If any thief actually succeeds in stealing a piece of palace, declare that it was a protective ploy to offer this thief some worthless junk, while the real unobtanium was safe and secure. [Answer] # **How about...no materials at all?** Okay, this isn't just an allusion to the namesake of this thread, hear me out: You take an entire planet, and spend years (or quicker with handwavium style tech) bleaching it of all life, completely purifying the water, and re-seeding it with specifically engineered fauna and flora making it the perfect garden world Maintain planetary temparature and atmosphere at your most pleasant choice You completely control the weather, making it perfect all the time, and then you don't need a palace. The world is your palace. No roof necessary. If you want walls, they can be hedges or stone or whatever beautiful thing you want. You can have your furniture and stuff out in the open, sleep under the stars, whatever you want Animals (if you have any) are kept at bay with sonic tech or something so they don't intrude in private places This is an almost impossible undertaking and maintaining its biosecurity will be an enormous cost...one that only an Emperor could afford [Answer] It is not the material, nor the location, nor the size, that counts in the end. It is the **sheer audacity** to build it in the first place that makes it so memorable. There is only one Sphinx, and even though it is just made of stone, there will never be another one like it. Same with the Eiffel Tower, and the Arc de Triomphe de l'Étoile. All made of simple materials, but all with a grandeur that will never be duplicated. Once you have demonstrated the audacity to build such a monument, there will be no other copies, because, well, they will just be copies of **your** audacity. Why would someone build the Sphinx? It is not really that functional. It really does not serve much of a purpose. It could easily be duplicated, the materials are not rare or exotic. Once built, the engineering becomes standard practice, taught in any engineering school. Any subsequent Pharoh could build one. Yet none did. The first and only Sphynx was built because someone had the sheer audacity to spend that much money in time and materials, that much effort, that much of the country's GDP, that much engineering technology development, on some structure, such that the construct becomes defined by that audacity, not by any intrinsic wealth or value of the structure. We admire the Sphinx not because of its cost to build, or the value of the materials that went in to it, but by the fact that one person said 'Build me a Sphinx', for no real reason except that he wanted something that no one else had ever built. And once he had it, no one else wanted one because someone already had one. Any duplicate would no longer exhibit anywhere near the original audacity. They would be an unoriginal imitation of his audacity. So this Galactic Emperor is going to be more concerned with the uniqueness of his construct, the fact that it is the first one, therefore the only one, to be built. He will not just want to build a bigger, better, more expensive palace than one already built, he would want to build something that had never been built before, that wasn't just a bigger copy of someone else's audacity. So yes, he is going to fill it up with perhaps very expensive stuff, but he is also going to use this material in a way that has never been used before, in a style never used before, in an effort never been shown before. The Sphinx was made of common material, but in a unique way. The Eifel Tower was just built of steel, but in a unique way. Same with all of our world heritage man-made sites. Even the Taj Mahal could be duplicted, or someone could even build a bigger one, but it would not be the Taj Mahal. Only the first one has audacity. So whatever material, or materials, he chose, the trick would be not just their cost, but to use them in a very unique, original, and audacious manner. For instance, not just plain old platinum, but platinum fused with diamonds built on a core of curium-247 and blended with - well, if someone described it now, it would not be an original blend, it would not be unique, it would not be audacious. Sure, someone else could manufacture it afterwards, but they would not be the FIRST. It would not show the same audacity as this Emporer showed. **Edit addendum** An example of **sheer audacity** would be, for instance, making the entire palace out of plain old gold, but doing it in just one pour of molten gold into one huge form. An absolutely solid gold palace, literally. Another absolutely audacious example would be making it out of one huge artificial diamond, cut and tunneled into one solid diamond palace. [Answer] Gold is currently sold at around 50 Euro/gram. During my university time I worked with an organic material which we paid 3000 Euro/gram, and it was only one of the many and similarly priced we had to use to build a OLED stack. That's the figure for any material which is produced ad hoc and in limited batches. And this is where you have to be careful: the very moment your emperor orders a supply big enough to make their palace, they will inevitably trigger scale economies, lowering the specific cost of any material they might think of. Therefore my suggestion would be to build a supercalifragilisticexpialidocious palace with excellent but standard materials and then cover its walls and ceiling with small batches of rare materials, like the one I mentioned above. Ordering 1 sample of 1 gram of 10k different rare materials will be much more costly than buying 10k grams of a single substance, because the order won't trigger any economy scale effect. [Answer] **Skulls of the rebels** It should be a rare material, or the emperor is not doing his job very well, but if there's a shortage then he can widen the definition of rebel to include people not turning in their library books in time. The emperor controls the supply of this material by definition, so it can be as precious as he wants. Besides that, there's a significant political advantage of crushing so many dissenters that you can use their corpses as construction material. [Answer] Sorry, but I can't resist to point out: Meantime, while the Galactic Emperor was struggling to find an appropriate material for his new palace, in the great city where he lived, one day came two masons. They let it be known they were builders, and they said they could craft the most magnificent construction bricks imaginable. Not only were their colors and patterns uncommonly fine, but buildings made of these materials had a wonderful way of becoming invisible to anyone who was unfit for his office, or who was unusually stupid... (based on [translation by Jean Hersholt](https://andersen.sdu.dk/vaerk/hersholt/TheEmperorsNewClothes_e.html)) [Answer] **Antimatter.** It is pretty freaking expensive to make, but the real, ongoing, terrific expense is maintaining it. Your palace of antimatter will happily explode and take half of its planet with. This must be prevented. No atom of normal matter must be allowed to touch the walls of the palace. It is good to have redundant systems for this. Perhaps on Boom Day the Emperor releases some little shreds of antimatter shaved from the palace, just so people remember. [Answer] # Force Fields The palace should be constructed out of **force fields**. Force fields, of course, require a constant energy input to keep in place, so if it is large enough to require a substantial portion of the energy output of all the stars under the GE's reign, payable as a periodic tribute, no mere planetary lordling will be able to aspire to that. No plating (for decorative or obscuring purposes as in some other posts) is needed. Instead, the relevant material is injected **into** appropriate cavities in the force field: smoke/clouds, gold vapor, plasma, nuclear reactions, even the souls of his foes... Also, makes for quick redecorating to match his many and varying moods. Of course, they can also go contentless if the mood for minimalism or naturalism strikes him. In a cruel twist of the original children's tale - have to get back to the question's title -, whenever a visitor appears that is full of doubt regarding the palace's existence or grandeur (or, come to think of it, that of the galactic emperor hisself), a crucial supporting force field can be made to temporarily cease existence (let's say a square in front of the galactic throne in the galactic audience auditorium) at the mere push of a button (or will they have thought interfaces then?) (Of course, I've done no calculations of the energy budget actually required, I'm just making things up as I go.) [Answer] **Solid Mercury** Mercury has always been the material of choice for emperors when they have to do something mystical and grand, though the mercury itself is readily available for all but making something out of it, using it, and maintaining it is altogether a different story. There are certain examples where mercury is solidified to create a structure, especially in the Hindu culture of making solid mercury Shivlings like [this](https://www.prweb.com/releases/2005/11/prweb305921.htm). You can take this idea, and make it grand, like really grand. [Answer] Make it out of blocks of White Rhino Poo, or some equally almost but not quite extinct creature. Sealed in clear plastic, of course. [Answer] Part One: Preventing Competititon. I note that a galactic emperor could pevent ambitious governers or kings of kings of kings or other subordinates from building more expensive or impressive palaces by regulations or laws. Or possibly by paying governors and vasal kings fixed salaries and and forbidding them from spending tax money on their palaces. Or by spending an amount of taxes fixed by law with penalties for exceeding. Or maybe the imperial government would manufacture prefabricated palaces to a regulan design for proconsuls and kings of kings and ship them out to the planets to be assembled. So you galactic empror wouldn't have to worry about his subordinates equalling or surpassing his palace if he coud prevent them from trying. Of course, independent kings of unconquered planets, and star systems, and rivals for the title of galactic empire ruling similarly large numbers of star systems could build palaces to rival your emperor's palace. Part two: Do Your Palace Research Before Writing. One thing which a witer could think about when designing the palace of a galactic emperor is reading about other fictional palaces in fantasy and science fiction. Of course some writers even of fantasy and science fiction suffer from a lack of imagination in designing impressive palaces. I remember in one of Poul Anderson's *King of Ys* fantasy novels the protagonist met with the real Roman Emperor Magnus Maximus (reigned 383-385) in the imperial palace at Trier. And the room was described merely as a "splendid throne room". And I had to think that either Anderson didn't do his research, or he was "damning with faint praise" the throne room in the imperial palace at Trier, by callig it merely "splendid". In *The Worm Ourobos*, by E. R. Eddison, Chapter One "the Castle of Lord Juss": > > She spoke, and the first low beams of the sun smote javelin-like through the > eastern windows, and the freshness of morning breathed and shimmered in that > lofty chamber, chasing the blue and dusky shades of departed night to the corners > and recesses, and to the rafters of the vaulted roof. Surely no potentate of earth, not Croesus, not the great King, not Minos in his royal palace in Crete, not all the Pharaohs, not Queen Semiramis, nor all the Kings of Babylon and Nineveh had ever a throne room to compare in glory with that high presence chamber of the lords of Demonland. > > > [https://paravel.net/ob.pdf[1]](https://paravel.net/ob.pdf%5B1%5D) And the presence chamber does have an impressive design. Though Eddison is unclear in some details of the description, such as writing about "rafters of the vaulted roof". As I said, the presence chamber is impressively designed, but the only thing about it which has never been equalled and surpassed on Earth in real history is: > > But a great wonder of this chamber, and a marvel to behold, was how the capital of > every one of the four-and-twenty pillars was hewn from a single precious stone, > carved by the hand of some sculptor of long ago into the living form of a monster: > here was a harpy with screaming mouth, so wondrously cut in ochre-tinted jade it > was a marvel to hear no scream from her: here in wine-yellow topaz a flying firedrake: there a cockatrice made of a single ruby: there a star sapphire the colour of > moonlight, cut for a cyclops, so that the rays of the star trembled from his single > eye: salamanders, mermaids, chimaeras, wild men o' the woods, leviathans, all > hewn from faultless gems, thrice the bulk of a big man's body, velvet-dark > sapphires, crystolite, beryl, amethyst, and the yellow zircon that is like transparent gold. > > > And the only thing impressive about those jewel capitals is the vast size of the original gems they were carved out of, unavailable on Earth. And I for one am not impressed merely because the builders had access to larger amounts of rare minerals than on Earth. That is a feature of the location, the result of luck instead of personal effort, and not a virture of the architectural skill of the designers. The banqueting hall in the castle of Carce later in the book, by contrast, is rather sinister looking, but it achieves its strong effect through architectural design instead of rare materials. And I think that later on there is a chamber built by the gods that is even more impressive. And in a future society people should be able to make gems at least as large as the gems in the presence chamber, whenever they want to, and so it would not be expecially impressive for a galactic emperor to use gems of that size. Of course if the Emperor synthasizes germs billions of times larger than anyone else has ever synthsized in order to carve verious parts of his palace out of those vast gems, that may be impressive. And you may remember seeing the movie *Excalibur*, 1981, in which the castle of Camelot appears to be made of blocks of solid gold. And to me that merely shows how dumb Arthur is in this movie, using gold in solid blocks as construction material, to build a castle with an architectural design that is not nearly as beautiful in shape as some real castles on Earth, instead of using thin sheets of gold as surfaces on the walls, as gold should be used. What form of decoration can be more spendid than gold and glass mosaics, for example? So I think that the emperor would be a little silly to obsesse about using expensive materials in his palace, instead of considering the size and the architectural design of his palace as the most desirable features for those who live in it, and the most impressive to those who see it. I also note a failure of research on Eddison's part when he lists the palaces on Earth which are suprassed by the presence hall in the castle of Lord Juss: > > Surely no potentate of earth, not Croesus, not the great King, not Minos in his royal palace in Crete, not all the Pharaohs, not Queen Semiramis, nor all the Kings of Babylon and Nineveh had ever a throne room to compare in glory with that high presence chamber of the lords of Demonland. > > > And I think that all the really great palaces on Earth were built after the ones he mentions, though before the ones listed at: [https://en.wikipedia.org/wiki/World%27s\_largest\_palace[2]](https://en.wikipedia.org/wiki/World%27s_largest_palace%5B2%5D) I am thinking of Nero's Golden House, the Flavian Palace built by Domitian, Hadrian's Villa at Tivoli, Constantine's palace at Trier, Germany, the Palace of Galerius at Thessalonika, the Great Palace at Constantinople, the Blachernae Palace at Constantinople, The White Palace at Ctesiphon, the Arch of Chosroes at Ctesiphon, The Round City of Baghdad, the Abbasid palaces at Samarra, etc. Part Three: Who'll Stop the Rain? And Why Stop the Rain? As an example of a science fiction writer's lack of imagination, in James Blish's *Mission to the Heart Stars*, 1965, the characters from Earth go to the capital planet of the Hegemon of Malis, ruler of the galaxy. When they enter the vast throne room, one of the characters wonders whether the throne room has it own weather and rain inside. And Blish describes it as a whimsical thought. Here is a link to a list of buildings with the largest interior volumes on Earth: [https://en.wikipedia.org/wiki/NASA[3]](https://en.wikipedia.org/wiki/NASA%5B3%5D) My answer to [https://worldbuilding.stackexchange.com/questions/153965/how-not-to-turn-volkshalle-into-a-rain-factory[4]](https://worldbuilding.stackexchange.com/questions/153965/how-not-to-turn-volkshalle-into-a-rain-factory%5B4%5D) indicates that some of the buildings on the list do have interior mist, clouds, and rain. So by having a character merely get carried away by their imagination and exaggeratedly wonder if the room was big enough to have internal weather, Blish was suggesting that a galactic emperor might possibly have had such a modest and humble throne hall that it was actually even tinier than the Vehicle Assembly Building and other buildings on that list! And unlike the asker of the question, I think that interior rain can be a feature, and not a bug, of the design. Maybe a galactic emperor's throne room would be large enough to have interior rain, and the interior weather would be controlled by technology so that it rained, and thundered at the right moments to emphasise the words of the galactic emperor, sort of the effect that Chosroes or Khosrow II imitated on a much smaller scale in his fabulous palace or temple building. Part Four: What is Art? And Which is the Most Impressive Art? So I think that the effect of a galactic emperor's palace should depend a lot on it's size, far vaster than anything ever built on Earth, and on the splendor and beauty of its architectural design, rather than the expense of its construction materials. Of course the materials used on the surfaces of the exteror and interior of the palace can be very expensive materials, if they are also very beautiful materials. I mentioned above gold and glass mosaics. Gold is expensive, even when used in thin sheets, and glass used to be expensive enough to be used in fine jewelry instead of costume jewels. And of course the colored glass cubes in wall and ceiling mosaics can be be repaced by cut and faceted jewels to make the mosaices even more expensive and beautiful - in fact, jewels have occassionally be used in mosaics. If your palace has countless millions of square meters of walls and ceilings covered with mosaics designed by brilliant artists and made out of gazillions of jewels, that will be expensive both in materials and artistry, and will be very impessive and beautiful. Another answer suggested that a palace could be filled with the greatest works of art from over the galaxy, and thus be a vast museum. But paintings, and rugs, and tapestries, and sculputures, are comparatively small and movable items, and are not exactly features of the building which they happen to be displayed in at the moment. And one of the greatest arts is architecture. So the Philadelphia Museaum of Art has a wing dedicated to displays of architecture, with rooms from various places and eras on display. And possibly the imperial palace could contain original or duplicate rooms designed by all the greatest architects from thousands of planets and millennia of history. Of course if the rooms in the palace are large enough, each can contain exact full scale replicas of famous works of architecture - or possibly the original buildings - from all the planets of the Empire. Or maybe even exact full scale replicas of famous cities in the empire. And possibly, if the rooms in the palace are large enough, they can also contain famous vehicles, like cars, trains, tanks, construction equipement, ships, submarines, airplanes, space vehicles, etc., from the history of thousands of planets and star systems. As I wrote above, arcitecture is often considered one of the greatest arts, and architecture often integrates painting and scupture, two of the other greatest arts, into its design. So by making each room in the palace a masterpiece of architecture and interior decoration, each room can be a gigantic and non portable work of art. And if some of that interior decoration is metal and glass mosaics, and perhaps using cut and faceted jewels for some or all mosaic parts, the interior artwork can be dazzling. And such glittering mosaics can be used on the exteriors of buildings. I used to walk past a building in Philadelphia at the right time of day for the gold colored metal in the mosaic around the door to reflect the sunlight down to me. I have read that part of the facade of the Baths of Caracalla in Rome was decorated with silver and glass mosaics. One facade of Nero's Golden House was said to be decorated with gold and gems. Part Five: Architectural Design. And here are just a few very brief suggestions about the architectural design of a galactic emperor's palace. If you Google for *At The Court of King Arthur* by Samuel E. Lowe, and search for images, a picture of the blue and white endpapers of one edition is like to be one of the results. On the right side is a knight on a rearing charger, and on the left there is a fairy tale palace to end all fairy tale palaces. Ever since i was a child, I have considered that to be the fairy tale palace design to strive to equal and surpass. And you should look at the floor plan of the Villa Romana del Casale: [https://en.wikipedia.org/wiki/Villa\_Romana\_del\_Casale[5]](https://en.wikipedia.org/wiki/Villa_Romana_del_Casale%5B5%5D) Aand the floor plan of the ruins identified as the Palace of Antiochos in Constantinople: [https://en.wikipedia.org/wiki/Palace\_of\_Antiochos[6]](https://en.wikipedia.org/wiki/Palace_of_Antiochos%5B6%5D) Those are good examples of ways in which the floor plan of a palace could differ from those of ordinary buildings, as it should. And to me the absolute best floor plan would be one which is made of radially symmetrical elements which are combined to make radially symmetrical units which are turn are parts of larger radially symmetrical units which in turn are parts of larger radially symmetical units, and so on and so on. Part Six: Sufficiently Advanced Technology. Also the palace of a galactic emperor should use various advanced technologies. Suppose that a galactic emperor built a super expensive palace, and then some historian pointed out that it lacks a technologically advanced feature which was used by some ancient emperor on Earth, and thus the modern palace could be considered less technologically advanced than a palace built millennia earlier by a much les advanced society. I think that the Galactic Emperor would feel humiliated, and thus his architects might feel tormented - by the imperial torturers. [Answer] **Human teeth of perfect quality, manually assembled into a single gigantic mosaic showing every variety of pattern, image and gradient imaginable.** To show the people's love for the Emperor, they get to participate: anyone who has perfect teeth can donate as many as they can spare. Coercion in this is of course taboo, as is any kind of monetary renumeration. But it only begins there: now an army of expert craftsmen have dedicated their lives to fitting the teeth together to form bricks and walls, like the Inca did with the [rocks at Machu Picchu](https://www.annees-de-pelerinage.com/machu-picchu-architecture-explained/). The important points: * as little material as possible should be lost to make the individual teeth fit, just choose the right ones instead of cutting them into standard forms. * obviously there needs to be some kind of cement or epoxy to hold it all together, but this should not be visible at all on the visible valls - no gaps, no lines. * even perfect teeth come in variety of shades, and the craftsmen are expected to use these so that every visible area is either uniformly colored, or shows abstract patterns, smooth color gradients, or detailed pictorial mosaics glorifying the emperor and his empire. Oh, and if you want something cozy to cover the floors of your palace, take a look at the insporation for this answers: <https://en.wikipedia.org/wiki/The_Carpet_Makers> [Answer] # An integrated circuit That's right, the entire palace is one single computer chip. The base price of the raw materials is laughable, a kg of semiconductor-grade purified monocrystalline silicon is just ~2000$/kg, cheaper even than gold. The real price points are ## Fabrication ICs are hard to make. Current-generation fabs are in the price range of [18 billion USD](https://www.eteknix.com/tsmc-building-fab-18-5nm-production/) and so hard to build that they're driving companies like [Intel](https://www.wsj.com/articles/intels-fabs-arent-going-anywhere-11595862957) out of the business. And that is for 2-dimensional Wafers with a diameter of 300mm. Fabricating one wafer [costs around 17,000$](https://www.techspot.com/news/86813-analysts-believe-single-tsmc-5nm-wafer-costs-17000.html). There's Fabs today that can build chips that are several hundreds of layers high - used for high-density SSD chips - but building a kilometer-high palace in one go? Building a fab that creates that sort of 3D chip from one monocrystalline piece of silicon would be madness - exactly the right choice for your emperor. ## Quality control Wafers have defects, e.g. from pieces of dust in the atmosphere. This is one of the major price points for chip production; modern processes give around one defect per 10cm² of wafer area. Every chip on a wafer must be tested carefully for defects and thrown out - or have parts of it disabled - if a defect is found. In practice this means that a significant fraction of modern CPUs and GPUs are thrown away just as they're manufactured. Naturally, the emperor's palace - manufactured in one piece from one monocrytalline piece of silicon - will need to have zero defects. Which *may* add a tiny bit to the manufacturing costs. Unfortunately, a 3D chip will be really, really expensive to test since test probes can't just touch any part of the circuit... ## Development There's a lot of awesome things that can be done directly in silicon. Apart from CPU cores, memory and storage you can build LEDs, capacitors, sensors for all sorts of things like magnetic fields, acceleration and pictures, protection diodes etc. Your chip can be radiation-hardened, or be a solar cell. Naturally, the emperor's palace will have every feature. Everything that can be conceived will be integrated into the palace. The palace will not just be a chip for the sake of being a chip; it will provide functionality. There will be no need to install electric cabling, light switches or computer screens in your palace because the building *is* these things. Fabricating a chip that has all kinds of different features at once won't be cheap - there's a reason they don't put RAM and CPU cores on the same chip, the required fabrication techniques are just too different. Intel spends [more than 10 billion dollars](https://www.statista.com/statistics/263562/intel-expenditure-on-research-and-development-since-2004/) on research and development every year, and that's mostly just for incrementally improving CPU cores, nothing else. Intel CPUs are still quite cheap nevertheless because of economy of scale. The emperor's palace, naturally, won't have any incremental improvements, or mass production. The Emperor can assign each cubic centimeter of palace wall to a different star system, and hold and pay for a great competition to see who can design the most impressive, most innovative cubic centimeter of wall, from scratch. Every star system will assemble a team of their most brilliant scientists and engineers in an attempt to outcompete their rivals and impress the Emperor; especially if he tells them that cost is not an issue, and, in fact, he'd prefer things to be on the expensive side. Of course, each cubic centimeter must be interconnected with the surrounding ones, and fulfill an actual purpose. Even having a few dozens of engineers working together on a complex project on Earth typically causes an immense amount of headache and management overhead, and makes your development costs explode far beyond what planned for. Luckily, that's an intended side effect. ## Conclusion The costs are literally inconceivable to me, but it definitely won't be cheap, and the emperor can add as much complexity, and show off as much complexity, as he likes. There's even nice synergy effects, if he chooses to share some or all of the beautiful technical advancements that are made while constructing the Fab or designing the Chips, similar to what happened with all of the money that was sunk into the Apollo project on Earth. One important thing to get right from the start is Framing. It must be made clear that the project isn't supposed to be *cheap*, or *efficient*, but that it's **supposed** to be prohibitively expensive and stretch the limits of engineering, science and the general economy far beyond what seems reasonable. There will be delays, and budget increases, and if these are not framed as part of the plan, the palace will just be perceived as a failed megaproject, like the ones that we have on Earth today (as a German I'm thinking of [Berlin Brandenburg Airport](https://en.wikipedia.org/wiki/Berlin_Brandenburg_Airport), which has become a running joke due to its "series of successive and embarrassing delays due to poor construction planning, execution, management, and corruption.", but I'm sure that everybody in the world, except maybe Switzerland, can think of a multitude of similar failed projects in their own country). This answer builds on the answers "A piece of history", "What matters is craftsmanship", so credit to those. [Answer] **Consider Active Support Structures** Whatever material chosen, the emperor can make his palace much more grand and expensive with the use of [active support engineering](https://en.wikipedia.org/wiki/Active_structure). This will allow much larger structures at a constant energy upkeep cost, much more than a simple governor could afford. [Answer] **Make a law that no structure on the planet may be taller than the Royal Palace.** Enforce it by **placing Space Elevator** on top of the Royal Palace which will naturally extends many tens of miles into space. Will be both unique and very, very expensive. Courtesy Yuliya Latynina. [Answer] Expensive could mean difficult to work with/manufacture. Tungsten, Titanium, and Chromium fit this bill nicely - I'm sure there are others who could list exotic alloys that are even harder. A friend of mine was going to get a Titanium wedding ring. He decided against it when a friend of his (who worked in the ER at a local hospital) pointed out that if he finger was broken a hospital doesn't have the ability to cut off a wedding ring made of titanium, so they may have to amputate. (He was an MMA fighter at the time so that was a real possibility) Titanium is also very strong and very resistant to corrosion so it would stand the test of time on any planet. Detail work with Titanium is VERY difficult I'm told. [Answer] You can make diamond from the ashes of people. Thus a palace made from people would be quite expensive. <https://www.algordanza.com/en/> [Answer] You want to go big? [Do it!](https://tenor.com/0aq0.gif) Megalomania is fun. Following on from [Xvilus Xv](https://worldbuilding.stackexchange.com/users/79716/xvilus-xv)'s [approach](https://worldbuilding.stackexchange.com/a/186513/67222): ## What about a reshaped / artificial *solar system* as imperial court or capital? Like [Justin Thyme the Second](https://worldbuilding.stackexchange.com/users/61270/justin-thyme-the-second) proposed, [do something of sheer scale and *audacity* and especially do it *first*](https://worldbuilding.stackexchange.com/a/186468/67222)! Legend has it, that Quin Shi Huang, the first Chinese Emperor, had a model of his whole empire built within his [tomb](https://en.wikipedia.org/wiki/Mausoleum_of_the_First_Qin_Emperor), with functioning rivers of fluid mercury and depictions of the constellations of the sky. Wealthy people in the 18ths would build artificial caves in their parks and few would even employ a real [human hermit](https://en.wikipedia.org/wiki/Garden_hermit) just for decorative purposes. Ancient emperors founded cities in conquered areas (there's a whole list of [Alexandrias](https://en.wikipedia.org/wiki/List_of_cities_founded_by_Alexander_the_Great)). Let's take **a solar system that defied the emperor** and that **had to be wiped out completely to set an example**, *death star* style. And now it is completely rebuilt as a ***world*, created by the emperor from scratch**. **What is closer to a god than that?** Roman emperors were already worshipped as divine. **Terraforming might already exist** in your world(s) as a pure necessity for colonizing uninhabitable planets, so you want to **go two steps bigger** for the residence of the ruler of everything: How many moons do you want to look upon from your residence planet? One for every spouse or military victory? And of which materials? Red rock, taken from the planet that marks your biggest conquest, rotating around your palace as pure decoration and a memorial for every visitor to see... Moons made of solid gold and silver, just because they look nice from a few thousand miles away? And that is practically only the immediate front yard. Maybe an entire planet is blown up, just to turn the royal residence into the closest planet to its sun... The planet itself could be completely reshaped and (re)created from scratch, imagine Dubai in Space, like [Xvilus Xv](https://worldbuilding.stackexchange.com/users/79716/xvilus-xv) pointed out in [his answer](https://worldbuilding.stackexchange.com/a/186513/67222). The **rest of that solar system** could be turned into the **imperial court** or **capital**, with other paradisiac planets for ambassadors, public authorities, as the hottest place to live for the richest and most important people in the world(s). The suburb of a god and the center of everything. The [gardening of Versailles](https://www.newswise.com/articles/gardens-of-versailles-had-political-and-military-purposes), reshaping nature, was a way to demonstrate the power of the monarch. * Depending on the advancement of technology and the livespan of your emperor the whole project might **still be under construction** during the time of your story, aimed to be the **legacy** he will leave behind, similar to medieval cathedrals that were built over centuries. * If he is the **descendant of a long line of emperors**, the project might be **quite advanced**, with several ancestors having contributed to and reshaped the galaxy themselves. * Maybe work has **just begun** / is about to begin and this is **causing a revolt of his subjects** and a whole subplot. * Maybe this is even **just a rumor, spread by his adversaries**, to turn the population against the royal family in their own favour - *the emperor is blowing up solar systems to play god, we have to get rid of him...* E. g. Nero was posthumously (and [most probaly wrongly](https://www.welt.de/kultur/history/article13627176/Kaiser-Nero-zuendete-Rom-gar-nicht-an.html)) accused to have started the great fire of Rome to remodel the capital to his wishes. Maybe the project is instead intended to explore new ways of terraforming to maximize the harvest and living conditions for every subject in the empire, but this gets misconstrued, be it deliberately or accidentally. --- Note: **Scientifically**, I have **absolutely no idea whether, how fast and with what effort that would be achievable**. But it sounds cool! [Answer] Something that is costly to maintain and generally of little utility is considered a "white elephant". These were prized animals for their rarity in the wild but kept by the wealthy as indications of their wealth. As they often came to be seen as far more costly to maintain than their actual worth they were given as backhanded gifts to others. Killing a white elephant would be considered a cruelty, as would setting it free in unfamiliar terrain. It would eat plenty and live for decades, potentially bankrupting someone of lesser wealth. Elephants are used as pack animals, and done so at a profit, but this would not be something one would expect a rare white elephant to do. It sounds like what you seek is a palace that is made of something rare, but also has a high maintenance cost. Perhaps I'm not being very helpful as I cannot think of anything specific. Just keep in mind that any large building will require considerable maintenance and that alone can make it a white elephant. Another thing to think of is what is considered the most valued place in an empire. I'll use America as an example. For many in the world getting to America, even as a visitor, is considered something to be valued since this is seen as something approaching an "empire" of great wealth and power. Then consider that getting to a center of great power inside the "empire", which makes getting to the US capital what people aspire to. Then comes getting to the White House, a highly guarded "palace" of sorts. Then the "center" of that is the Oval Office. This is a place people want to visit and that's because that's the office of the President of the United States. Just the fact that the palace contains the emperor makes it valuable no matter what it is made of. A similar thing can be said of a religious example. People will want to visit Rome as that's a pilgrimage to see many holy sites. Inside that is Vatican City. Inside that the Sistine Chapel. And that's valued because it's where the Pope and College of Cardinals meet, as well as being a place bearing incredible works of art going back centuries. A place of awe doesn't have to be a white elephant, or a seat of power for someone of political and/or religious influence. It can bring awe out of it's utility, quite the opposite of a white elephant. People desire to visit places that are examples of engineering marvels. They will want to see hydroelectric dams, military fortifications, nuclear power plants, large telescopes, particle accelerators, and tall towers. Which takes me back to the examples of DC and Vatican City where people seek out information that few can know or see, contained in books or the minds of the inhabitants. The libraries and museums that contain this information is valued. Consider the value of information. The value of the instruments of science or espionage. A place like DC, Vatican City, or other capital cities will not only contain the "palace" but also information, large engineering projects for creating and protecting this information, and the people in authority of it all. One such engineering feat that would bring awe could be something like the one and only known stable fusion reactor in the empire. This would be of considerable value not just in the power output to keep the capital complex lit and heated but provide power for weapons, growing food, powering industry, and so forth. This would be something that few would be allowed to even see out of concern for keeping the secrets of how it works and to defend it from sabotage. If there's a rare material to be sought then perhaps it's the plasma within an artificial star that powers the center of an empire. Having a single such reactor is likely something no empire could rely on as that one point of failure would make too much of a target. Perhaps the palace sits upon the largest of them, or the first of them. ]

[Question] [ **Edit:** A few people have argued that this question is off-topic, and as I write this it looks like it will be closed soon. However, I have written a new (and hopefully better) version of the question at [How could an inter-temporal banking system work?](https://worldbuilding.stackexchange.com/questions/114178/how-could-an-inter-temporal-banking-system-work), and I hope that you will take a look there. **Original question below:** Suppose you have a working time machine. You decide to go back 50 years and buy a house; after all, in 1968 the average cost of a new house was [just about $15,000](http://www.thepeoplehistory.com/1968.html), quite a bargain! The problem: How do you transfer $15,000 back in time with you? Cash, obviously, won't work, unless you somehow have access to paper currency that was printed before 1968. (Not likely: [the lifespan of paper money is ~10-15 years](https://www.federalreserve.gov/faqs/how-long-is-the-life-span-of-us-paper-money.htm), so good luck finding large quantities of 50-year-old cash.) Maybe you could bring gold back with you? Not a good idea -- gold currently costs about 30 times more per ounce than it did in 1968, so in order to have bring back enough gold to buy a \$15,000 house, you'd need to start with $450,000 worth of gold. So -- how would you transport $15,000 worth of wealth back in time with you to 1968? **Edited:** Many of the answers below are really addressing the broader question "How could you get rich using time travel?" Quite a few of them actually involve transferring wealth from the *past* to the *present*, or from the *further past* to the *more recent past*. The question was intended to be more specific than that; if it helps to focus, suppose you have a single-use time machine, and that you are planning to travel to 1968 and retire there. The cost of living then is relatively low; you just need to figure out how to get your 2018 wealth back to 1968 in a usable form. "Buy something that's cheap now but expensive then" is a good model, but what, specifically, could you bring and sell in sufficient quantities? [Answer] Knowledge. Bringing wealth to the past requires simply knowledge. You have the outcome of horse races, lotteries, inventions, share prices, stock market falls etc etc etc. Your head could easily hold enough information to make you rich beyond your wildest dreams if you can go back in time........ [Answer] You're incorrect about bringing cash back to the past. You could easily bring back 15,000 in \$2 bills. Back in the 1950s the US government decreased the printing output of \$2 bills, causing people to hoard them. So many were hoarded, that they are not in the least bit rare. The vast majority of \$2 bills, even from the 1950s are worth \$2. These old bills are so common, they are at face value. Most people don't even realize the \$2 bill has never gone out of circulation and is printed to this day, making 1% of all US paper currency. If you put in some time and effort, you an easily acquire 7,500 \$2 bills that are old enough to be valid 50 years ago. In addition to paper money, there are coins. Coins will stay in circulation until they are physically worn out and sent back to the US Treasury by a bank. It is extremely common to find a coins over 50 years old still in circulation. While it would be a pain to carry \$15,000 in change, even quarters, it is technically possible. I just rummaged through my coin and money collection and found my a binder full of \$2 bills ranging from the 1800s to the 1970s. Sadly, only the oldest ones are worth more than \$2 and most of them not by much. I also have countless US Bicentennial quarters from 1976. The mint actually produced more of these quarters than regular quarters and they are also extremely common. They are worth a whopping 25 cents apiece. [Answer] ## Synthetic Diamonds Have a lab make you a couple kilos of 1.0 to 2.0 carat flawless synthetic diamonds. Have them cut to optimal brilliance then take them back to the 1960s. Visit high end jewelers in a large metropolitan area. The quality of the gems should speak for themselves. After that, the rest is just haggling. Even if the jeweler is able to talk you down, you don't care because any price that they ask will be a huge profit for you. If the diamond is large enough, you should be able to make a considerable sum on just one to the right buyer. In 2018 dollars and market, a 2.0 carat diamond will cost upwards of \$15K. You also don't want really large stones because the market for exceptionally large gems is very small. You want liquidity to get the cash for your house, not to get into the diamond trade (which is a bloody bloody affair.) Make sure that the lab doesn't work for deBeers since synthetic diamonds will often have a fingerprint in the diamond to identify it as synthetic. We want true flawless diamonds, not fingerprinted. ## Retirement A few kilograms of diamonds should be plenty of wealth to live on for the remainder of your natural life. Don't live in the cities so you get atmospheric lead poisoning. Your stash of diamonds is easily worth tens to hundreds of millions depending on current prices. Also, given that your stash is just a tiny fraction of world output, no one is going to come back to you if you sell a few. [Answer] ## Take a calculator A Ti-84 will do nicely. In 1968, some of the largest, most expensive equipment was computing equipment. The transistor had only been invented in 1959. Integrated circuits are only 1966. Computers in the late 60s were the size of refrigerators. As a time traveler, you can carry back things that are far more valuable than gold. Far, far more. Just take back any modern graphing calculator. Bring back a few actually. If you can contact IBM or DEC, you should be able to sell one of those calculators for millions of dollars, easy. Just that little calculator represents decades of software and hardware advances that they would give their arms and legs for. Much of the hardware they won't be able to duplicate but a sufficiently motivated engineering staff would make huge strides. You can probably get a better offer by playing IBM and DEC off each other. Avoid selling to the government because they'll just lock you up and appropriate the calculators. Not ideal. ## Negotiations Negotiating for wealth transfer will take some care. These are a set of minimal steps that should be taken. Remember that the devices you hold will look fancy to any normal person who sees them. They probably won't know what they're even looking at unless you turn it on, maybe not even then. In the 1960s there's maybe a few tens of thousands who will understand and appreciate what you have to show them. 1. Buy 10 Ti-84s. Take them with you when you jump back to the 1960s. Rig each calculator with an internal acid bomb that will destroy the internal electronics after a certain period. 2. Take some form of identity to open a safe deposit box with. Maybe take a little gold as collateral. 3. Open three safe deposit boxes at three different banks in three different towns. Divide the calculators between those deposit boxes. 4. Hire the best 1960s contract lawyer you can find. You will need them to act as your agent. 5. Find a bank that will let you use their back room. Pay them in gold. Rent one of their deposit boxes too so the calculator doesn't need to leave the bank to be secured. Under no circumstances are you to take these devices onto IBM or DEC property. You have very little physical strength there. Do not give up that advantage. 6. Find an electrical engineer at IBM or DEC. Avoid all military and governmental contacts. Don't worry about meeting with managers yet. 7. Invite them to meet you at the bank for a demo of an electronic sliderule. The bank will lend credibility to your claims and also assure them of their physical security. 8. For the demo itself, just let them play with the calculator. Maybe provide them with the calculator's manual too. Have a slide rule on hand for quick verification. Keep this demo short. Any engineer worth their salt should go absolutely bonkers with this kind of capability in their hands. Expect the kind of emotional response from the engineer that people had when the iPhone first came out. 9. Give the engineer your lawyer's card. Tell them that you have a limited number of these devices available and will be putting them up for sale. Also say that you are looking for bids from multiple companies. State your opening bid. Make it at least US\$10M. Should they be interested, they should contact your lawyer. The engineer will be dumbstruck but tell him the innovations contained in this device are easily worth tens of billions. 10. You will likely have to give demos to multiple levels of management. Do not meet anywhere besides the bank. 11. Expect all manner of shenanigans in various attempts to get these devices from you. Why pay \$10M when you can just rob someone and get it for basically free? Maintain your physical security at all times. 12. Expect all kinds of delay tactics to draw out negotiations. Set a quick expiration date for the negotiations. Ensure that the calculators will self destruct shortly after the availability window. They aren't worth much to you but invaluable. Any intimations that they just can't pay are bull-hocky. IBM made US\$871M in [profits](https://www-03.ibm.com/ibm/history/documents/pdf/1885-1969.pdf). A mere \$10M for a device that's thirty or forty years advanced is laughably cheap. 13. The contract will be simple. Foreach calculator transferred, the buyer will pay \$10M, transferred to this bank. On day of transfer, the buyer will verify operation of the calculator then it will go into an escrow deposit box controlled by the bank. Make sure to disable the self-destruct device before transfer to the escrow box. The bank will handle the escrow process after that. 14. After purchase, transfer the funds to lots of different accounts. Switzerland sounds lovely. On second thought, this is really complicated. Just take back a highly valuable resource (gold, diamonds, knowledge) and sell them for cheap. At low enough prices, all assets are highly liquid and other than authenticity claims, no one will ask how you got them. ## Retirement Since you're retiring here, you could probably get a job with IBM/DEC as a "Future Consultant". Any modern skilled profession will have meaningful contributions to make in the 1960s and 1970s. [Answer] Go back further in time. Fifty years ago you might have trouble finding something that is cheap now but expensive then. If you go farther back, that becomes easy. ### Aluminum According to [this answer](https://worldbuilding.stackexchange.com/a/53710/2113) to another question: > > emperor Napoleon III reserved a prized set of aluminum cutlery for special guests at banquets. (Less favored guests used gold knives and forks.) > > > Modernly aluminum is cheap (we make soda pop cans out of it). So buy some ornate but inexpensive aluminum cutlery and go back in time to sell it to Napoleon. Napoleon pays in gold. Buy paintings with the gold. For example, Vincent van Gogh was all but starving while alive. He'd have sold practically any painting for peanuts. French coins from Napoleon's time would still be worth at least their gold weight if not more to collectors. ### Art supplies Heck, van Gogh would probably have traded paintings for art supplies: canvas, oils, etc. According to [Wikipedia](https://en.wikipedia.org/wiki/Lost_works_by_Vincent_van_Gogh): > > So I went into my basement one day, picked up all drawings that were somewhat offensive, put them in a big bag and when that bag was full, I brought it to the paper factory of Tilburg to be ground to paper; I've had a few dimes for it. > > > So if you can find a few dimes, you could buy a bagful of van Gogh nudes. ### Steel Take a modern steel katana or broadsword and sell it to a Roman emperor. Use the proceeds to buy statuary. Store the statuary somewhere that you know will persist. Unearth and sell it in 1968. ### Spices Spices used to be incredibly expensive. Some were shipped overland from China. Get paid in gold and bury the gold. Dig it up in 1968. ### Diamonds They used to find [diamonds](http://www.thesolomon.co.za/heyday-of-diamond-mining.html) on the surface of the ground in South Africa. E.g. [Big Hole](https://www.sa-venues.com/attractionsnc/big-hole.htm): > > It all began as far back as 1866 when a man called Erasmus Jacobs found what he took for a shiny pebble on the Orange River banks. To cut a long story short, it was later sold in London, after it was determined to be a 21.25 carat diamond, for £500. After a further two diamonds were found in the area, a diamond rush ensued and miners arrived in their thousands. The hill disappeared in a flurry of prospection, as picks and shovels yielded 2 722 kilograms of diamonds. > > > Use your modern knowledge to find the diamonds first. Sell a diamond so as to make your claim for land. Once you own the land, you can sell it or partner with someone. [Answer] Just to answer the question and not verify it sense (after all why only 15K to buy house when you can own Wall street). Look at this [](https://i.stack.imgur.com/byb0G.png) To have 15K in 1968 you need around 681 pieces of 2n5085 transistors. Prices taken from [Fairchild Semiconductor price list 1968](https://archive.org/stream/TNM_Fairchild_Semiconductor_price_list_1968_1N_di_20171111_0066#page/n7/mode/2up/search/2N222) [Answer] Bringing back weird oddities like calculators or transistors is going to cause questions. Even something which is available but expensive is unlikely to be in the hands of a private individual in significant quantities (e.g. the transistors), so as soon as any questions are asked, you've got no trail as to where they came from, so they'll (at best) look stolen. The simple answer is to forge old cash. The forging technology available now would exceed the detection capability in 1968, and whilst (depending on your jurisdiction) forging out-of-circulation currency may still be a crime, if you’re caught it’s probably much easier to explain as a “historical project” or for re-enactment etc. Crucially though the materials needed to forge out-of-date currency are probably not controlled any more, so you won’t get on any watch-lists buying them. [Answer] How about things that got cheaper? A bale of Nylon or other specialist plastics, rare earth metals. Maybe simple electronics. Consumer goods that were a luxury in the 50's but common these days. Also medicine. The chemicals are the same but you might be able to find things where the patent lapsed and are now a lot cheaper. [Answer] ## You really need to think about *Inflation*: Your best method would be in fact, to find dollar bills that are 50 years old and take them back in time. You mention that a house in 1968 was worth only 15,000$, yet you have overlooked one extremely important factor; **inflation**. To drive this point home, a house in 1968 was not worth 15,000 \$ in today's currency. It was worth 15,000\$ in 1968's currency. So using an inflation calculator (<https://data.bls.gov/cgi-bin/cpicalc.pl>), 15,000$ in 1968 is the equivalent of **110,210.85**\$ today. The first thing you will notice is that while this is substantially cheaper than modern housing prices, you will still only be able to get maybe 4x today's value in assets if you translated your money point for point into the older currency. So the real secret sauce is to hoard older dollar bills. It might take a bit of searching but at 7x its actual dollar for dollar amount and (7x4) 28x times its modern value when buying houses, this is probably one of the best ways to go. If you want to just take money back into the past at roughly a point-for-point value then you should focus on non-perishables. You have already mentioned gold (which hasn't really changed too much in value since 1968 after accounting for inflation). If you take gold back in time it would be best to take it back to before the discovery of North America. This is because that will be before the gold rush. So since gold was more scarce back then it would be worth a lot more. If not gold, you can pick other precious metals, and so on. A lot depends on the specifics of how you want to transfer the money back into the past. For example how far back, how much, at a profit, etc. Just don't fall into the trap of thinking that just because things were apparently cheaper back in the day, that they were actually cheaper. Often they were not in the money/effort required for that day. ## If you want to make money: Go back to 2009, spend 1000$ on bitcoins, and be a millionaire today. No questions asked. The currency is used for a lot of illegal activity anyway so no one will know where it came from. *Some quick math:* Price of bitcoin in 2009 = 6 cents. Bitcoins you can buy with 1000$ = 16,600. Price of bitcoin in 2017: 17000. Profit = **283.3 million** - 1000 $ One trip will suffice, and you can retire in the modern day. [Answer] You can just buy old money from collectors. If you use 1000 dollar bills you'll only need fairly small amount. Unfortunately prices for the latest 1934 series seem to start with 2000 dollars, so you'd pay a premium. As a bonus you can get 1934 bills fairly easily from eBay and prices are not significantly over 2000 dollars. 500 dollar bills might be cheaper. Ones printed in the 1940s are apparently not rare enough to be collectible, so you'd pay around the nominal price. These would also be what was likely to be in circulation in 1968. It might take some time to collect the bills, but I am fairly certain money collectors have their own forums and magazines where you can advertise you are buying 1940s 500 dollar bills. For that matter any business that sells and buys old money will probably be happy to help you since they already have the needed connections and know all the right people. [Answer] The simpelest way may be creating a series of small jumps to get 'current-day' currency. Inflation being what it is, taking back gold or another similarly precious material is either going to be uneconomical or hugely impractical. What I'd propose is to go around and get the oldest dollar (or whatever the currency is in your world) bills or coins you can find that are still going for 1\$ per \$. Collect a suitably large amount of them (15.000\$ worth) in your case. Go back in time to a year after when they were printed and exchange them for older bills of the same value. Keep in mind that you may lose a small percentage of your seed money to living expenses and exchange fees, so bring a little more than you think you'll need. At a 2% exchange fee, you'll need just under 16.240\$ to start with. Fire up the machine again and go back in time, repeating the process. Near as I can tell, most bills tend to stay in circulation for 12-ish years, so you'll probably need 5 jumps to get back to 1968. Once there, you'll have your 15.000 in cash to pay for a house. It may be worth the effort to exchange at least a part of your 10-year old bills printed last year once there. Otherwise, the house's seller may ask questions as to why you're paying cash for a house with suspiciously old-looking bills. [Answer] **Don't forgot you're going back in time... then coming back to the present** If my understanding of the question is correct, the aim is to be able to have/afford a house in present day but only pay $15,000 for it, or at least pay as little as possible, and you have access to a time machine of some sort that can take you back 50 years, I'm not sure if that's only 50 years or it can do more or less as well. but I digress, if that is the case Although Gold is worth a lot less dollars 50 years ago, due to inflation of the Dollar not value of Gold. it is still the most hassle free way to transport wealth back in time. It's how you use it that counts So Today Gold is roughly 1200 Dollars an ounce, and back in 1968 it was roughly 290 Dollars an ounce, so if you were to buy 12,000 Dollars worth of Gold today, you'd have roughly 2900 Dollars in 1968, not great but... as others have suggested, you can get old money now, you might have to pay twice as much for it, but if nothing else you know Gold is going to be worth 4x what it was worth then, so spend as much money now to get the old bills, go back and spend all that money on Gold then bring it back and sell it... Alternately... **Why buy a house? Buy Shares!!!** In theory, you could buy $10,000 worth of gold today go back in time and then sell that and place the money into stocks that you know full well will mature well over time. you may only be able to but a few different stocks but buy a few here and there and as they mature they split doubling your amount, then have dividends placed into a couple savings accounts. this is important as account that don't get accessed every few years get flagged for checking, and if they don't get used after this then they can be closed, the money would still be owed to you but the interest rates would no longer pay out, so simply having some letters put in with a lawyer, which they will send every couple of years to transfer some money between the accounts should see you fine right up until about 2001, when banks security changed and you would have to go in to do things like this, (be aware that some small town banks still to this day will make transactions by letter) The dividends are paid on say (Very low estimate) 10 cents a share and that is usually paid 4 times a year (this changes with certain companies and requires them to always make a profit, but lets assume you did your research and knew this would happen) so 40 cents a year, for 50 years is 2000 cents, 20 dollars! yay... OK so not that much, but that's only for one share, so owning say 200 shares in company X would net you, $4,000 not bad return so far, but still not made your money back until you sell the shares. but!!! as a company matures over time they often split their shares, Microsoft for example has split their shares 9 times since 1986 to maintain a reasonable trading range So if that were the case then those 200 shares would be if split however many times your chosen company splits (it's all in the research before you go) No Split: 200 Shares = $4,000 1 split: 400 Shares = $8,000 2 Split: 800 Shares = $16,000 3 split: 1600 Shares = $32,000 4 Split: 3200 Shares = $64,000 etc, you see how this is going, there's no point buying the house back then when you can buy a much bigger house in the present, and that's not even taking compound interest into account, and this is only the dividend money, not the value of the shares themselves One very simple way of getting round this is if you can go back more than once, $10,000 worth of stocks in 1968, and that would net a huge amount over time in dividend payouts, Go back in 1984, and invest in Red Bull, this would increase the divided payouts even more... then go back in 2000, take those divided payouts and invest in Apple or Microsoft, then come back to the present, you wouldn't have changed much in terms of human history (let's just ignore chaos theory for this) and yet, if you take inflation, and even some very low estimates the dividend payouts alone would make you a multi millionaire [Answer] One very important point when trying to pull a cross-time investment scheme. **Don't forget about the five year rule.** For all the suggestions about investing, putting money in the bank, etc, almost all banks have rules about orphaned accounts. If an account, a safe deposit box, whatever, is left untouched for a period of time, the bank may seize the assets. They're required to try to find the owners, which used to be done by taking out newspaper ads and other public notices; they probably do it on the web now. So if you put the money in a bank and come back fifty years later, that money will almost certainly be gone, long since absorbed by the bank. You'd either have to make a very unique arrangement with the institution (which they'll probably STILL try to get out of after thirty or forty years have passed) or you'd have to pop by every three or four years on the outside to get the interest posted in the passbook or whatever to keep the account active. You'll almost certainly have to arrange some paperwork along the way to record the transfer of the assets from you to from your "father" or "grandfather", after whom you were named, and yes, I do resemble him quite a bit, I get that a lot. [Answer] You could take a copy of a few valuable patents that you could file under your own name and sell rights to interested companies. You could minimize the impact on the "timeline" by selecting patents made by large companies and selling it back to them. The result would only be extracting a couple million from large companies like IBM, General Motors etc which wouldn't redirect the course of history. [Answer] I would like to disagree with the answers that say you can in fact bring 15,000 cash back in time. Or from my perspective, anything that was in circulation in the time you are traveling back to. This is especially important if you are trying not to disrupt (or as little as possible), the economy or events of the past. Money (and many other items) have serial numbers. If you use money printed from 1950 that you brought back from the future, there will now be duplicates of those serial numbers, and thus 15,000 into the economy that was not there previously. Instead of bringing something that existed physically and reintroducing it as a duplicate in the past, I recommend a two part system for buying that house. 1. Learn a skill you can take back in time and easily find a job with to 'naturally' make money. 2. Bring back ample knowledge of event outcomes. Stock market, sports team betting, etc. With these two steps you can make your own money in the time you travel to, and use knowledge from the future to make it far faster than everyone else. I think possibly important but probably out of scope is your identification as you were likely not born yet, and you are trying to work and buy a house. [Answer] If you're willing to go back farther in time than 50 years, then you will want to stock your time machine with soda. Specifically cans of Soda. Then travel back in time to the Napoleonic era, use the instructions to chemically extract the aluminum from the cans, and sell that. Before the synthesis of Aluminum, the metal was insanely valuable. Napoleon's finest dinner wear was made of the Aluminum and was used to impress the finest of dinner guests... the Gold Dinner wear was used for the lesser important people he had to entertain. Over in the U.S., when the Washington Monument was completed, it was capped with an ingot of Aluminum (rather than Gold) to symbolize the wealth of the nation. Today it's a fairly cheap metal and so common to find and turn back into the real stuff it can easily net you an impressive gold mine. All you have to do is avoid being noticed having so much of the stuff. Heck, you can even laugh about the whole ordeal with your time traveler's club buddies by telling them that the Aluminum used to make Napoleon's finest goblet was formerly a Mountain Dew can. [Answer] # Commodities **Commodity answers to this question become much more profitable, interesting, and educational for readers the further back you go**. It's fun to see how **gold** had a great return in pre-exploration Europe but [a huge mistake in the Levant just after 1324 or the US in 1869](https://smartasset.com/insights/four-people-who-singlehandedly-caused-economic-crises); of course, the whole reason for the Age of Exploration was willingness to risk the lives of entire flotillas for the profit on **spices**—mainly pepper, cinnamon, ginger, cloves, cubeb, & galingale—in Europe [after the Islamic conquest of Egypt ended Hippalus's direct route to India](https://www.economist.com/node/179810) but [before the final crash in the 1660s](https://www.economics.utoronto.ca/munro5/SPICES1.htm); **cinnamon** and **cassia** were pricy in Ancient Egypt [because of their importance in embalming rituals](http://www.compoundchem.com/2016/10/27/mummification/); meanwhile, **salt** was a lucrative source of trade [in West Africa](http://www.smithsonianeducation.org/educators/lesson_plans/currency/essay2.html), [for Venice](http://www.venicethefuture.com/schede/uk/174?aliusid=174), and [in China](https://en.wikipedia.org/wiki/Salt_in_Chinese_history); [it was never as crazy as people make it out to be](https://www.smithsonianmag.com/history/there-never-was-real-tulip-fever-180964915/) but if you still want to head to 1630s Netherland if you have **tulips** handy; Napoleon's **aluminum** dishware stuck with our history buffs enough to have already shown up in 2 answers (one of them even got it right that [it was post-1855 Napoleon *III* and not c. 1810 'Napoleon'](https://gizmodo.com/how-aluminum-cost-more-than-gold-1575564897)); &c. &c. &c. **But 1968?** That's already a time with fairly well developed exploration, tech, & markets. You get occasional things like [the insane 2006–7 run up in uranium prices](https://en.wikipedia.org/wiki/Uranium_bubble_of_2007) (a major Canadian mine flooded) but unit prices in real terms mostly get smaller over time except for short-term bubbles produced by speculators and by attempts to corner certain markets ([fake soybeans in 1963](https://en.wikipedia.org/wiki/Salad_Oil_scandal); [silver in 1979–80](https://en.wikipedia.org/wiki/Silver_Thursday); [copper in 1995–6](https://en.wikipedia.org/wiki/Sumitomo_copper_affair); [propane in 2004–6](https://www.nytimes.com/2006/06/28/business/28wire-bp.html); [nickel in 2006–7](http://news.goldseek.com/GoldSeek/1183932000.php); &c.). Obviously you could make a fortune over a few years from some initial capital by buying up **oil** ahead of the [1973 OAPEC fiasco](https://en.wikipedia.org/wiki/1973_oil_crisis). You should certainly avoid cash in favor of securities and commodities [during most of the '70s and early '80s](https://en.wikipedia.org/wiki/History_of_the_United_States_(1964%E2%80%9380)#%22Stagflation%22). But there's no commodity that's sensibly portable and currently available and cheap that you could sell at a very high markup in '68. # Electronics Green's [hilarious answer above](https://worldbuilding.stackexchange.com/a/114001/35633) covers just how complicated this is going to be, at best, and that even the simplest products would be reverse engineered and alter a massive chunk of the future after a 5–10 window. Something as small as a decent spreadsheet program could potentially alter major elections. At worst, you out yourself as a time traveler; **you'd spend the rest of your life at a black ops site run by one side of the Cold War**. Word getting out of you providing anything useful under torture would mean the other side *at best* assassinates you; at worst, you survive and they gamble with a nuclear first strike. # Laptop Obviously the laptop itself would represent enormous innovations and is thus hugely dangerous. Just keep it hidden, along with your surge protecter and two-prong adapter. What you're aiming for (besides having some decent games, music, and entertainment) is storing databases and algorithms. You *could* keep a list of major longshot winners. Without discipline, you'd quickly have the mob or police chasing you after the first few payouts. [Here's a list of recent potential time travelers](https://bleacherreport.com/articles/1065407-greatest-sports-bets-of-all-time#slide11); [except for this guy in Staffordshire](https://www.mirror.co.uk/sport/betting/uks-biggest-betting-wins---3570873), they made a lucky hit once and not again or already had a reputation for large low-odd bets. You could hide for a while in major events—Proud Clarion was a 30:1 longshot at [the '67 Kentucky Derby](https://www.kentuckyderby.com/history/year/1967)—but they don't offer the biggest payouts. More importantly, every win against a casino or bookie is money out of their pockets. What actually works longterm is **systematic horse betting**, where the house takes a cut off the top of all bets and doesn't care who wins among the punters, as long as their 'luck' isn't *so* egregious that it stinks of race fixing. By the 1990s, [Bill Benter had an algorithm](https://www.bloomberg.com/news/features/2018-05-03/the-gambler-who-cracked-the-horse-racing-code)—[published in large part by *World Scientific*](https://www.worldscientific.com/doi/abs/10.1142/9789812819192_0019)—that loses plenty but wins with enough of an edge to beat the system and rake in multimillions. Have a database and a system whose announceable process and copious losses legitimize your winnings, whether legitimate or based on your foreknowledge. (The shifts in track behavior based on your winnings would likely start reforming the races themselves, invalidating the exact records you returned with.) With enough capital, a similar process could be done with **trading algorithms** used by hedge funds' automated traders. Run slower or even human-based versions of the same processes and cheats; avoid individual rocket shares but [follow investment algorithms that are known to have worked consistently for your expected lifetime](https://www.fool.com/investing/small-cap/2006/12/16/how-to-cheat-the-market.aspx). Or, if you treated morality as your characters' dump stat to max out their chutzpah, pull off stock and **investment scams** [before their expected dates](http://www.tothetick.com/archives/2237). (This might be something a stock-based time traveler would have to default to, as their interference in the market began to shift investment patterns and invalidate the original expected winners.) The most lucrative **patents** to take back (assuming you don't want to run your own factories or cripple the internet in its cradle by sitting on most of its processes) are going to be effective pharmaceuticals historically discovered a few years later: [taxotere](https://en.wikipedia.org/wiki/Docetaxel) for cancer, [lipitor](https://en.wikipedia.org/wiki/Atorvastatin) for heart problems, [viagra](https://en.wikipedia.org/wiki/Sildenafil) for circulation issues, &c. You can pretend you're a recluse chemist who stumbled across sth by accident. As profitable as they are, however, you're still going to need to take a small lump sum to sign over the patent or sit on it for *years* as you negotiate with someone who can shepherd it through FDA trials and then mass produce and market it. [You might throw in [some patents for AIDS treatment](https://www.minnpost.com/education/2018/02/patently-lucrative-intellectual-property-makes-big-money-u), cheap DNA marker sequencing, and [nixing Stanford's treatment of rDNA licensing](https://labiotech.eu/making-dollars-out-of-the-recombinant-dna-biotech-patents/) as a humanitarian gesture, though you might be hard pressed to explain their importance.] The golden age for easy-once-you-know-it patents was the late 19th century; there are still some sitting around though. 1968 is the year a guy at 3M developed the low-tack adhesive that permitted [post-its](https://en.wikipedia.org/wiki/Post-it_Note) but they didn't figure out how to use it until years later; Lonnie Johnson, Sarah Blakely, and Paul Brown are still decades away from creating [supersoakers](https://en.wikipedia.org/wiki/Super_Soaker), [Spanx](https://en.wikipedia.org/wiki/Spanx), and [valve tops](http://www.mcclatchydc.com/news/nation-world/national/article24465613.html) for ketchup and shampoo bottles but any of them could've been made or approximated in '68. **Fads** are lightning in a bottle and it's hard to know if you could profit off one by coming in earlier than when they caught the Zeitgeist. Still, you've got [waterbeds](https://en.wikipedia.org/wiki/Waterbed) ('68), [pet rocks](https://abcnews.go.com/US/pet-rock-captured-moment-made-creator-millionaire/story?id=30041318) ('75), [mass cocaine running](https://en.wikipedia.org/wiki/Pablo_Escobar) ('75), [crack](https://en.wikipedia.org/wiki/Crack_cocaine) ('84), [collectible card games](https://en.wikipedia.org/wiki/Magic:_The_Gathering) ('93), &c. &c. that you could get an effective and immoral tout to bring out ahead of schedule. [Answer] # Use your time machine more than once. Buy a few really old coins - at least 100 years, preferably more. Go back and invest it in a very safe bank. (You know which ones will survive the Crash :-). If you invest \$100 at that start then after 200 years at 4.0% interest you'll get nearly 300k$ at the end. [Answer] Go back further in time, and take back something like lace that is relatively cheap now, but expensive back then. Sell it, and then use that money to buy an "undiscovered" oil field. The move forward to the 1950's, sell your oil field for a bundle, buy your house, and for good measure, buy stocks that you know will explode in time. [Answer] I agree with many of the answers that the most practical thing you can bring is knowledge. You will probably need a few strategies to earn huge amounts of money. Bring back something worth a little bit and is easily exchanged (such as gold, don't worry about the value, it is worth approximately the same then as now, adjusted for inflation, anyway, you just need seed money), then gamble in games with known outcomes to make more money, but you don't want to earn too much this way or you'll attract the wrong kind of attention. Once you have a little bit, use the money to buy supplies, transportation, etc. to help find a treasure that's already been found, but not at the time you are going back to. One example of a treasure you might be able to find: [California couple finds $10 million in buried treasure while walking dog](https://www.reuters.com/article/us-usa-california-coins/california-couple-finds-10-million-in-buried-treasure-while-walking-dog-idUSBREA1P03M20140226) I don't think you want to purchase property in the past since it would probably be difficult to do that without valid ID, and then claiming it when you get back to the future will probably be difficult as well, especially if you haven't been paying your property taxes. The property will likely be declared abandoned and auctioned off before you could claim it in the future. So, with the money you get from the treasure, you can invest it in some sure-fire stock purchases (as others have mentioned). Ideally, you would get actual [paper stock certificates](https://www.investopedia.com/articles/02/101802.asp) that should still be good when you come back. Once you have your stock certificates, come back to the present and redeem them. You will probably want to bury the certificates somewhere you can find them so they age properly. Wouldn't want them to determine they are counterfeit due to their apparent age. Also, make sure you find them somewhere that you can prove you are legally entitled to them even if you didn't purchase them (how could you have, right?). [Answer] Other answers are great. What I'd do is bring a \$2 bill and knowledge of the 'future' to go back and earn it myself. Using base 2, we can calculate that you will have to double your money 14 times to end up with `2^14 = $16,384`. If you can get more than 1 \$2 bill, you can augment the base in the equation to see how much faster you can earn your money, i.e. bringing 2x\$2 bills, the formula is now `2*(2^13) = $16,384`, so essentially you require 1 less transaction. 4x\$2 bills would be `4*(2^12)`, 12 transactions required 8x\$2 bills would be `8*(2^11)`, 11 transactions required You can start to see a diminishing return, where you need to start out with exponentially more \$2 bills to keep shortening the number of doubling transactions required. Unless you can get your hands on 16, 32, 64, 128... \$2 bills easily, probably best to just bring 1 or 2, and get the payoff from a few more required transactions. That seems like way more fun, anyway. [Answer] By calculating the value of gold in the age you want to go to and bring the equivalent of $ 15.000 of that year with you? The REAL problems you'll be facing will be connected to your level of knowledge and social development. Example: Back in the '68, racism was still rampant in the US. You really wouldn't pass for a 'nigger-lover'. Also watch out for other rights you take for granted today: you'd be mistaken for some 'dirty commie'. ESPECIALLY when it comes to your schooling: you'd know things in science and history that, if caught by the wrong persons, could lead you to a world of trouble with CIA. And finally, you'd need to deposit your gold in more than one bank so not to draw unwanted attentions -I mean, imagine a mr. Smith coming to town with a cache of gold acting like it was the most normal thing. ]

[Question] [ I am still puzzled by the original *The Planet of the Apes* movie from the 70's. How come that sentient species invented weapons, but was unable to develop powered flight, or spacecraft. Thus, the question is: **What could prevent a sentient race from going to space?** Assume an earth-like planet, and human-like species. This race should get through similar history build-up as humans, with one twist: They should not go to space. What is most obvious factor to prevent them to go to space? By "space" I mean not being able to pass [first orbit](https://www.youtube.com/watch?v=RKs6ikmrLgg), and never launching satellites. But otherwise, I would like to get this race to at least Earth 70s technology level. This planet has all the resources needed to get to the space (basically think of alternate Earth) [Answer] **To make sure no space flight, just make the planet a little heavier.** Based on chemical rockets, the cost to LEO is pretty terrible. If you increased the planet mass by a relatively small percentage, creating a chemical 3 stage rocket to deliver a payload (not payroll) becomes prohibitive or even just impossible. 25% more mass for the earth should do it. Many other lift designs are possible, but we use chemical rockets for a very good reason, the other designs have even less thrust, or have other negative feature (a pulsed nuclear bomb a.k.a. Orion comes to mind). --- Consider the retired space shuttle, its payload was 27,500 kg, but the launch mass 2,030,000 kg. I.e., the payload was not much over 1 percent of the total mass., were gravity only 2% higher, the shuttle would not be able to deliver any payload, etc. If you count the entire orbiting section, the mass is about 130,000 kg, which is still only about 6% of the launch mass. Planes are a much different story, payloads can be a much bigger percentage because they don't have to carry their own oxidizer. Some designs would be able to work with a heavier planet, but they will be quite expensive to develop. It is unlikely that such would ever happen without earlier experience with chemical rockets. Recommended article, [The Tyranny of the Rocket Equation](http://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html) --- Michael Karnerfor does make a good case for balloon launch platforms in that you can at additional expense in development cost and per launch cost have a more efficient launch. [NASA has explored this](https://space-academy.grc.nasa.gov/y2008/group-project/proposal-for-a-balloon-assisted-launch-system/), figuring a possible benefit of about 25% fuel reduction (or conversion into payload). Similar arguments can be made for a number of alternative space launch ideas, such as launching from a plane, launching from the end of a sled on a ramp. If you are persistent enough, you certainly could launch a small satellite from a balloon even with a 25% increase in planetary mass. You could find that you could only launch very small payloads (balloons are not a very stable platform), and they will be very expensive compared to our launch costs, esp. in higher development costs. Unless the value of being in orbit is well understood, no-one would bother. The lone exception in 1970 tech that I am aware of is using pulsed nuclear bombs, which have their own problems, such as releasing large amounts of radiation into the atmosphere and numerous EMP events. Quite a few [non-rocket solutions](https://en.wikipedia.org/wiki/Non-rocket_spacelaunch) have been proposed, many are supplements to chemical rockets. The OP mentions 1970 tech level, most of the non-rocket solutions - including a balloon launch platform do not seem to be 1970 tech level. Maybe you need a slightly more massive planet to keep the Michael Karnerfors out of orbit with 1970 tech, but the principle is simple, more planetary mass makes LEO much harder and it is already very hard. Maybe you think 25% increase won't stop all LEO at the 1970 tech level, OK how much then 35%, 50% - the principle is the same regardless. Also note that micro satellites make less sense with 1970 tech under the heavy planet model. You need computers to do smart things to make a micro sat useful for many things. The [Apollo guidance computer](https://en.wikipedia.org/wiki/Apollo_Guidance_Computer) was introduced in 1966, it required 55 watts of power and weighted 32 kg. Because micro sats would not be useful for a large variety of tasks, the value of balloon and plane assisted launches would diminished as you could not launch large satellites without a very expensive launch platform. [Vanguard](https://en.wikipedia.org/wiki/Vanguard_1) is perhaps the best example example of what value of non-smart satellite could accomplish. --- I believe several people are ignoring something. If the cost is too high compared to the value, no-one will launch things into orbit. For example, if you are willing to be ludicrous, you could launch a LEO satellite from sea level using chemical rockets on a planet with 200% of earth's mass. You would need perhaps 10 rocket stages to put a very small payload in LEO. The cost would be perhaps 1 billion USD per kg or more plus many billions in sunk development costs. It is not just a matter of physical impossibility, just that no-one would do it. The expected value would be far too small to motivate such an action. So, maybe you think national pride, or a publicity stunt could motivate such a stunt. This seems very unlikely to me giving that the risk of a failure after spending a huge amount sum would still be quite large. Looks at the failure rate of the earlier orbital attempts -- and this stunt would be far more complex. National leaders, or publicity seekers do not like to be associated with huge failures either. I cannot envision anyone doing such a thing. Just saw this new [article on Real Clear Science](http://www.realclearscience.com/blog/2017/07/06/if_earth_was_50_larger_we_might_be_stuck_here.html) -- they conclude 50% means we might be stuck here. Thet probably copied my stuff :-) [Answer] ## **A bunch of debris in orbit** This is especially flavorful if the world in question has been inhabited for a long time, and the current civilization is built on the ruins of one much more advanced. At orbital speeds/escape velocity, tiny flecks of paint can be devastating to finer equipment, and large debris would obviously cause catastrophic damage. I'm not a fan of the film, but *Gravity* is a good example of what can happen. As is the manga *Planetes.* Here's a link, as well: <https://en.wikipedia.org/wiki/Kessler_syndrome> [Answer] When dealing with other societies of human-like species, there's a lot of stuff that you can play with, other than technical. A few other reasons that hasn't been mentioned could be emotionally, culturally or even religiously based. 1. Old religious texts says that the seed of evil fell from space (or something). While the religion doesn't have a massive hold on all technological advancement, it still has created a collective societal fear of space. 2. Politicians sometimes campaign on not letting people violate the 'purity of space'. Just as clean water is a human right, so is a pure space above us. Sounds strange to us, but is something that could be developed further. 3. Due to atmospheric or other conditions - there's no stars visible. No moon either. Space looks like a completely empty void. No use exploring it. Exploring the deep oceans is seen as much more 'scientific' pursuit. People who talk about the void too much are seen as hacks. 4. Regulation. The current societies that are capable of developing the technology for reaching space are under heavy regulation from whatever Governmental unit. Not that this has to be a political point being made. Regulation could be as a result of conserving fuel, which is used to just barely generate enough power. All excess uses of rocket fuel have to be approved by a very bureaucratic process. [Answer] Mankind had [firearms since the 10th century](https://en.wikipedia.org/wiki/Fire_lance) CE, and [rocket fireworks since the second century](https://en.wikipedia.org/wiki/Rocket_(firework)) **before** the common era. Still took us until the 1800's to get air-borne, 1900's to get wing-born and all the way to the 1960's to get a human into space. The short answer: The apes have not gotten that far yet. Firearms or even rocketry does not equate to space-faring. [Answer] Going to space is extremely difficult. Even to say the human race has been to space is pushing the truth a bit considering how very few of us have actually been there. The chances of any of us who would like to go there getting there is minuscule. (So in a way we're all prevented from going to space) To answer your question, look at why "we" went to space and take away that factor. It wasn't simply the next logical progression from firearms, you don't just point your gun at the sky and expect to launch a bullet into orbit. For the human race, there was huge political pressure to do it, between the end of World War 2, where German rocket technology in some form was discovered by both the Soviet Union and the United States, allies in the war who were afraid of each other. Even then, there was no reason for space travel - it was a ridiculously costly endeavour for no return. But the heads of rocket research on both sides happened to push for it and managed to convince their respective governments that if they didn't, the other would and be able to drop missiles from orbit onto their respective countries. So take away World War 2 or the German research or the Cold War or even the fact that both Superpowers managed to get access to the technology, and no space travel. [Answer] **Hostile Aliens** [](https://i.stack.imgur.com/NPzH5.png) If the planet were frequented by hostile aliens who blew up anything that flew more than 20km above the ground, it would make going to space significantly more difficult. A fledgling sentient species would first have to develop shielding capable of stopping a death ray before they could even *think* about planning a space launch. Plus, gathering the requisite manpower to conduct such a launch would be difficult when everyone is busy toiling in underground chocolate quarries. [Answer] A planet with dense, constant cloud cover might be a strong demotivator. One of the reasons we were drawn to explore the solar system is that we could SEE it. If you lived on a planet with a dense, constant cloud cover, it might not even occur to you that there is anything else up there but sky. [Answer] ## Lack of motivation The space race happened at a point in our history when the shooting war had stopped. It was a way of showing technological dominance over the opponent while not actually killing anyone or risking getting killed. If: a) the shooting war was still going on or b) there was no challenger in the race then there's a reasonable chance we would never have put a man on the moon, simply as a result of the massive cost and risk involved, as can be seen by the fact that we haven't been back in a very long time. In terms of a continued shooting war, there's a possibility we'd be in space a lot more, as another front to the land/sea/air/space, war but it would be a very different use of the low earth orbit to the one we have now. As importantly there are the industrial scale factors. Automatic weapons can be built by one man in a shed in Pakistan (AK47 clones mostly). They don't need a massive industrial complex. Going to space needs massive manpower and access to a level of technology a world away from even well built assault weapons. [Answer] A bit OT to your question, but a nod to "The Planet of the Apes" - ie. a civilization built on the ruins of an older one: **The older - "original" - civilization had already used-up some necessary resources or raw-material needed to allow space-flight to happen.** It wouldn't even be necessary for a particular resource/raw-material to be completely used-up, as long as all the easy accessible sources were exhausted... ie. what you could get at with primitive technology. Nor would it have to be something directly associated with space-flight; it could just as well be lack of resources preventing them to reach a necessary technological level (eg. can't make electronics), or preventing them from making necessary tools (eg. computers or welding-equipment - or even mining/extraction-tools). One would also expect that space-flight would come pretty late in their technological evolution, so if lack of resources preventing them from reaching prior steps - eg. combustion engines, air-crafts, plastics - space-flight may be difficult to achieve... and perhaps more important, difficult to imagine. +++ What if some disaster - lets say a new ice-age - devastated our civilization, decimated our numbers, destroyed most our of knowledge, destroyed our machines... *Could* we start from scratch? With no easy accessible ore of iron or copper... with no easy accessible oil or coal... Remember oil isn't just used for combustion-engines, it's also used to make most plastics. I think it would be difficult to reboot our society - even though we would know it *could* be done and much about *how*. [Answer] Nothing of value in their solar system, not even of scientific or curiosity value. No moon, no planets, no asteroids. Maybe even some kind of anomaly that prevents the stars from being visible. As far as they know, their planet (and I guess their star) is the sum total of existence. [Answer] ## Eliminate their motivation (This meant as a compliment to [separatrix](https://worldbuilding.stackexchange.com/users/16295/separatrix)'s answer.) **No fear of extinction** In addition to the Cold War and the space race, we also have the fear of a future cataclysmic event. Some scientists are worried that if the Earth is struck by a big enough piece of space debris, or if we have a global thermonuclear war, our species will cease to exist. Their solution to this fear is to spread the human race to other planets and other habitable places in space. Earth has a major extinction event in its past. If the planet where your alien civilization is has never had a major extinction event, and has never had weapons capable of destroying the entire population, then they have no reason to fear that their species could be wiped out. This eliminates the desire to spread the species out in order to prevent the risk of extinction. **Stable population size and resources** Another reason we might want to leave Earth is that our population is continuing to grow and consume more and more resources. We may yet be a long way off from using up all our natural resources and running out of room, but we're close enough that we're worried about it being a problem in the future. Spreading out to the stars is a solution. If your aliens have already developed sustainable energy sources and eliminated all significant reliance on limited resources, then expanding to other worlds to obtain more resources isn't an issue. If your aliens have reached a stable 1:1 birth:death ratio, then population growth isn't an issue either. Interestingly, humans are trending towards that already. **No large-scale organization** Going to space requires a massive effort across many disciplines and over many decades, even centuries. If your aliens are not given to working together on the required scales, then developing technology to transit through space will never occur. This doesn't prevent technology from developing, but it keeps any technology requiring large group efforts from developing. Most inventions would be the efforts of individuals and small groups. **Pessimism** One of the biggest arguments against going to space in the first place was and is that it's not worth the cost. One of our motivators was optimism and imagination. We look to the stars with hope. If your aliens are a bit more pessimistic and risk-averse on average than we are, they might see space as a worthless vacuum with little to offer, and not worth the expenditure of effort and risk to reach it. Maybe they don't even have enough interest in the stars to have studied them much through telescopes, and they see stars as a flat blanket rather than as distant suns similar to their own nearby one. [Answer] Imagine life on the large moon of a gas giant planet. Like Europa, it has a thick crust of ice. An ocean is hundreds of km deep, with volcanic vents at the bottom. It's in a harsh radiation belt of the planet. We find that hazardous and it damages electronics. But here life *depends* on it, playing over the ice layer to fix nitrogen etc. The beings far below don't get exposed directly to it any more then earth's core bothers us. Beings develop intellegence and technology. They must leave their deep habitat and enter areas where the loss of pressure is fatal, as water itself acts differently at such depth! The pressure alone makes ensymes fold differently, and the [subtle difference](https://en.wikipedia.org/wiki/Water_model) in molecule packing affects the biochemistry. Then they have to get through the ice. The radiation kills their cells and kills any advanced electronics. They don't see any sky, and are not drawn to the heavens. Why haven't we reached the Earth's mantle? They have two directions to explore, and don't know that one of them even leads to "space" as a concept. To them it's more like us reaching the core. [Answer] Let's consider that of the [200,000 years that we've been around here](https://en.wikipedia.org/wiki/Anatomically_modern_human), we only have been capable of launching satellites during the last 59 years. The fundamental issue here is that a technological society has to be based on modern science, but the scientific method you need to use to do science properly, is very counterintuitive. For almost all our history, we had to survive in Nature. We needed to trust the information you get from authority figures, your parents, and other respected people who have a lot of experience and knowledge. That knowledge is not in practice reducible to more fundamental basic facts to primitive people living in Nature. So, our brains have evolved to respect authority. Only about 3 centuries ago was the modern scientific method invented as a better way to make progress. But, of course, this only worked because enough knowledge had been accumulated to allow more and more information about Nature to be extracted from experiments and observations. It may be the case that once a civilization has developed far enough to start to do science and build a technological society, intelligent machines will appear in a matter of a few centuries and that these machines will take over society. Space flight is very expensive, if we were to push for a manned mission to Mars, then it may well be profitable to spend, say $20 billion to develop an AI robot that would do the job as well as humans. So, space exploration may be a natural boundary where AI systems will take over from their biological ancestors. [Answer] Intelligent species don't go into space because it's **too expensive**. Crewed space flight is **prohibitively expensive**. An intelligent species will cooperate for the benefit of all. Resources will be shared for sustainable development, to optimise the well-being of all sentient beings in short and long term, based on a utilitarian framework. Perhaps it uses AI to estimate the optimal solution. Because the species are intelligent, they don't destroy each other in warfare. Although they do have a limited use for explosives in mining and road construction, the development of rocketry is not considered. --- P.S. Apart from near-instantaneous global communication, weather forecasts with unprecedented accuracy, environmental monitoring (Earth observation), progress in science and technology, sheer awesomeness, and peace, what has putting stuff in Earth orbit ever done for *us*? [Answer] You can make a Nuclear War that decimates all population, stopping the technological development, just like the Krogans in Mass Effect. [Answer] **Deny them fuel.** Leave them a planet in which all the easily accessible fossil fuel sources *have already been depleted*. No cheap fuel - no industrial revolution - no technology driven society - no space travel. Sure. Let's say they learn the secrets of the water pumping windmill, find electricity, develop hydro power, come up with an electrical grid, electric trains. But there is an inherent social consciousness about **economy of energy** - it is too precious to waste. As are metals, without unlimited fossil fuel to power mining and smelting. They'd love to use U-235 to achieve a critical mass and breed fissile fuels from abundant U-238 and Th-232. But the found uranium is much more depleted of U-235 [than it ought to be](https://en.wikipedia.org/wiki/Primordial_nuclide), making this almost impossible. It would be a "slow society" - canals and electric trains. The personal automobile would be an absurdity. Now someone proposes to **launch a single vehicle weighing 3000 metric tons** - where every gram of that vehicle is made of an exotic metal or synthetic fuel that can only be made at staggering energy expense. **Used once and destroyed!** This would not correspond with the society's values. --- How do you engineer such a world? Easy. **We're doing it right now.** We're mining all the easy-to-get fossil fuel and minerals. What happens if our civilization collapses and another one tries to industrialize 2000 years from now? They're going to find our leftovers - veins we abandoned as uneconomical to mine. That doesn't mean there's nothing there, it just means it's a lot more work, which makes it rather inefficient. Eventually, their engineers will figure that a previous society mined out those resources before them. That will be particularly obvious with anything nuclear. [Answer] A physiology that requires taking lots of liquid with them to survive. They evolved in the sea. They require taking lots of liquid with them to "breathe", maybe because they need to be continually immersed in it (they breathe through their whole skin?) Liquid is much heavier than air. Crewed missions to orbit would be prohibitively difficult and expensive. [Answer] Religion: A state religion which opposes space flight, but other than that has very little strong statements or controversial opinions, so it's impossible to disprove, provokes nobody into fighting against it. As an example: ``` Praise Mother Earth! For She guided us into existence. For She is the soil beneath our feet, the air we breath and the waters we swim in For She gives us food and drink For She is the majestic beauty of the mountains, the roaring waves of the sea and green wonder of the jungle which is our inspiration For she is the torrid desert, the biting polar wind and venomous snake which proves to us Her might and teaches us to hold firm together and be kind to each other in the hour of need because we are all Her creatures and part of her She is our one and everything in this otherwise bleak and empty universe, our one spot to thrive, our one spot to live, out one spot to be! So keep this in mind, for now and eternity ``` Make this the core tenet of the religion of the absolute majority of people on the planet. There will be no reason to separate this from the state or fight against it because really, you need to *work* if you want to interpret this in an offensive way. So the constitutions will probably also contain it, or the monarch or oligarchs will adhere to it. No one will really fight against it, because the worst you can really say against it, is that it's pointless. The biggest stretch about this is that people didn't change it over the course of time to confirm their bigotry or help them keep power and similar things. There is no economic need to (personally) go to space anyway, other than our fascination with it and basic research. Both of which could be directed at the Earth itself too, there is plenty of it which is fascinating and which we know little about. So I don't think they would fight against it too much. At some point they would want to develop satellites for practical and scientific purposes at which point they would probably reinterpret their religion to mean that they can send objects to space as long as they stay out of it themselves and even later reinterpret it again so that they can do manned space travel, but you said you want technological advancement at a 1970 level, so if this buys you a 100 years that would be plenty and it could conceivably give you much more than that. [Answer] How about much less ability to withstand acceleration than humans have? That's likely to make the rockets much less efficient when carrying sentients that survive the trip. [Answer] Like Giancarlo said, War. But not necessarily a nuclear one. Say your species have been separated in two clans since millennia, or maybe a more recent rupture because of politics (the Cold War w/o nukes). Both hate each other so much they sacrifice everything to defeat it. The thing is, their powers are equal, so their strikes only succeed in halting technological advances. If this happens before major technology emerges (Middle Ages), well you could end up with a perpetual war freezing a species, making it ignore all but the enemy. And you get lots of work to implement a cool backstory to explain the war. [Answer] How hard can it be, it ain't rocket sc... Oh, wait, it is! Designing rockets is hard. Building rockets is hard. Not blowing them up during the launch is hard. Aiming those pointy things to the correct point in space is hard (space being big and all). And not only is it hard, it's terribly expensive, our bodies aren't build for it and it's mighty inconvenient to stay up there for long. There's no real reason to prevent a species from going to space. Under normal circumstances I'd say we weren't technologically enough advanced to make it worth it when we started. However, worth is subjective. The worth increased rapidly simply because of war and the threat of war. See [colmde's answer](https://worldbuilding.stackexchange.com/a/44967/643). Also keep in mind that Planet of the Apes deals with sentient species *bigger* than ours. Much bigger. So not only is space exploration hard (we have barely scratched the surface ourselves), it's even harder for them. It's also more inconvenient for them. [Answer] A race of intelligent jellyfish on a large planet (it needn't have a large surface gravity). * They evolved under water and require large quantities of heavy liquid to even exist. * Even developing the chemistry and the high energy processes to start thinking about rockets would be exceedingly difficult. Metals aren't abundant or easy to mine, except for some submarine nodules. * Physiologically, they can't stand high accelerations (they might die or fragment into "daughter" semi-sentient beings: that's their reproduction cycle - when they're ready they move ashore and are broken into pieces by the waves. The daughter colonies prosper in the rich waters near the shore, and some of them eventually regain the sentient depths). * They can't stand micro-gravity at all (even human beings have problems for long periods; *their* long period is a few minutes). Such a race might not even be *technological* unless incredibly motivated (it happens to the pom race in *Spinneret*), and it would need an external technological kickstart (Milton A. Rothman's *Heavy Planet*), or some phlebotinum such as gravity fields (Asimov's *Victory Unintentional*). Further demotivators could be religious, too. Or the planet might be quarantined by another race (Star Trek's *The Abode of Life*), possibly for their own "good" (the planet Parval in Weber's *Empire from the Ashes*). Or you might think of fancier limitations. For example these beings have evolved to live in mental symbiosis with each other - being out of reach of the supersonic consciousness CB of the colony is first physically painful and mentally exhausting (sort of an Internet Deprivation Syndrome), then causes mental breakdown. You'd need a very rare kind of psychopath, a "loner", to even *think* about becoming an astronaut. [Answer] What if the aliens lived on a planet that's within the habitable zone of a red dwarf? Because it would have to be so close to the star, planets like these would surely be tidally locked. That means that, with one side constantly facing the star, half the planet would be scorched while the other is frozen solid (aside from a narrow habitable band between the two). A species living on a world like this would definitely have a lot of challenges to face if they ever tried to reach orbit. Spacecraft would have to withstand temperature changes from hundreds (or even thousands) of degrees above the boiling point of water to temperatures well below zero degrees Celsius. Plus, due to the radiation pressure of the nearby star, it would be very difficult and very expensive to attempt to keep a robotic spacecraft in orbit (let alone a manned mission) ]

[Question] [ I'm an alien. I made a bet with another alien, that I can: * Stay on Earth for at most 100 years. * Start a religion It may be based on existing one, but be meaningfully different. E.g. Latter-Day-Saints (Mormons) vs. mainline Protestants counts. Different versions of Anabaptism are not "different". Sunni vs. Shia counts. Reform Judaism vs. Orthodox one counts, but reform Judaism vs. Reconstruction doesn't (not meaningfully different enough). * Have that religion last EXACTLY 500 years (give or take 5 years, but your bet pays much more for more precision). Anything outside of 5 years margin, you lose. * Bet conditions prohibit you from actually specifying 500 years anywhere in the content of your religion. Or any specific dates 500 years in advance. * Bet conditions prohibit you from interfering IN ANY WAY with that religion beyond initial 100 years. This, among other things, means you can't leave a miracle generator with 500 year battery, and predicate the religion on miracles keeping coming. * You can't change people from regular Homo Sapient biologically. No raising their lifespan to 500 years. No ticking biological timebombs in their genes. * You can perform modest "miracles" using "magic" alien tech, that are confined to, say, the scope of what Jesus Christ or Mohammed was reputed to have done (modest matter generation, modest energy generation, some advanced medicine for few people. Mass-depressors to ensure your followers can succeed in attacking an enemy city or two; but no super advanced weapons - and especially no super advanced weapons left in human hands for 500 years). ALL your miracles must expire in the 100 year period - no verifiable trace of them should be left once you leave earth except hearsay or naturally-looking consequences. **What can you do to structure your religion, so that it lasts 500 years BUT doesn't last beyond that, guaranteed?** Not that it should matter, but the bet is pretty-high-stakes, let's say 100x average lifetime salary if you win, and lifetime of indentured servitude if you lose. And you can't get out of it. * Timeframe is flexible, you get to pick anything in recorded human history (so, let's round to 2000BC to 2000AD). * You have approximate knowledge of how Earth history went in that entire time period, meaning you can engineer your religion and your timings to co-incide with major **trends**. BUT, you have only approximate knowledge (because of butterfly effect, or because your psychohistorical formulas have a large error margin, whatever) - Columbus may have sailed to New World in 1492, OR in 1481, OR in 1511. Or he may have died at birth and another dude discovered New world 50 years later. So you can't simply say "found a religion in MesoAmerica 500 years before Cortez and hope Cortez wipes it out for you in just the right 10 year timeframe to win the bet". Remember, allowed margin of error is +/- 5 years. [Answer] **I'm going to put my religion in Pompeii.** I'll found my religion in [Pompeii](https://en.wikipedia.org/wiki/Pompeii) around 420 B.C.E. My fundamental promise to the inhabitants of the city is that I will never let the volcano, Mount Vesuvius, hurt them for as long as they worship me. The frequent but non-devastating earthquakes will keep them interested in pleasing me. In 79 C.E. they will know I betrayed them as their entire city is buried in ash, killing everyone almost instantly. Any followers I had outside of the city will lose faith in me once they learn that I destroyed their home city. [Answer] The solution is, of course, **cicadas**. I quote [Wikipedia](https://en.wikipedia.org/wiki/Periodical_cicadas): > > [Periodical cicadas] spend most of their 13- and 17-year lives underground feeding on xylem fluids from the roots of deciduous forest trees in the eastern United States. After 13 or 17 years, mature cicada nymphs emerge at any given locality, synchronously and in tremendous numbers. After such a prolonged developmental phase, the adults are active for about 4 to 6 weeks. The males aggregate into chorus centers and attract mates. Within two months of the original emergence, the life cycle is complete, the eggs have been laid and the adult cicadas are gone for another 13 or 17 years. > > > Using your alien tech to create such cicadas with 20-year, 21-year and 23-year life cycles should only leave “naturally-looking consequences”, as they are not too far off from reality. The main idea is this: * Place your religion on a remote island. Forbid them to leave it. * Make its central food supply a plant that is eaten by cicadas. * In the year 80, place a considerable brood of 21-year cicadas on the island. It will emerge again in the following years: 101, 122, 143, 164, 185, 206, 227, 248, 269, 290, 311, 332, 353, 374, 395, 416, 437, 458, 479, 500. * In the year 86, place a considerable brood of 23-year cicadas on the island. It will emerge again in the following years: 109, 132, 155, 178, 201, 224, 247, 270, 293, 316, 339, 362, 385, 408, 431, 454, 477, 500 * In the year 100, place a considerable brood of 20-year cicadas on the island. It will emerge again in the following years: 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 420, 440, 460, 480, 500 Thus, you have no year with more than one brood emerging until you have all three broods at once in the year 500. With the right tuning the cicada populations, the human populations and the amount of cultivatable land, this should cause a devastating famine in the year 500, without a strong risk in the other years. To assure a thourough destruction, there are some details to consider: * Make the religion strictly vegetarian. This way, the adherents cannot resort to eating fish, cicadas or other animals. As they did not suffer from famine before, they should also have no reason to modify this aspect of the religion, and a sudden adaption is unlikely without dropping the religion. Moreover without experience, it will be difficult for your adherents to begin fishing from one day to the other. * Ensure that all food sources are subject to cicada attacks. * Use the religion to prevent any action against cicadas to keep their populations stable. * Forbid any records that would allow a bright inhabitant to spot the pattern. For the same reason prevent analysis of cicadas (that would allow distinguishing the broods), e.g., by the following. * Make your god a god of cicadas. Explain the losses to one cicada brood as a sacrifice to this god. However make it a clear promise that the cicadas will never eat more than one brood would eat, not even as a punishment or similar. This way eventual survivors of the famine will likely drop the religion, not only because of contradictions to reality but because it represents something they will utterly hate. * If necessary, forbid storing the main food source for a longer time. * As an amplifier, make the burial rites demanding for the society, e.g., have family members lay down work for a few days and enter a fasting of mourning. [Answer] This is loosely based on [Theik’s answer](https://worldbuilding.stackexchange.com/a/20305/308), but removes the cheating element: * Go to a point in time 500 years prior to some predictable astronomical event, such as a comet or a solar eclipse (or use one of the tricks in the other answers to achieve a timing). * Create religion A on a remote island that can only host a small population. Incorporate the following into the religion: + pacifism; + not leaving the island; + some harmless, but avoidable everyday practice like wearing clothes, shaving your hair, etc.; dying is clearly preferrable to giving up this practice; + everything useful for survival. * Create religion B on every surrounding island or land. Spread it far enough to ensure its survival and ensure that there are no larger powers around it that may destroy it. Make this religion believe in the following: + general aggressiveness, but not so much that it is in danger of destroying itself; + strong hostility to everybody who follows the practice encoded in religion A; + strong proselytic tendencies: everybody they do not kill must be converted to their religion or die; + they shall explore and invade the region around the island of religion A when the astronomical event happens, but not before that (possible reason: God is sleeping there and wants to be awoken at that time); + everything useful for survival. This way, religion A will peacefully survive until the day, when it will be butchered by adherents of religion B (or [die of infectious diseases](https://en.wikipedia.org/wiki/Native_American_disease_and_epidemics) brought by them). Possible remnants will be converted or at least have to give up their religion. The sheer size of religion B should guarantee that somebody will be willing to do the job, even if it schisms or new religions come up. To ensure that other people do not invade the island, choose it sufficiently remote such that sailing there is risky. Also, you can encode its position using astronomical facts that only manifest after 500 years. The advantage of this strategy is that you do not need **all** adherents of one religion do something extreme (like commiting mass suicide or falling from belief) on a signal but just need **some** adherents of another religion commit genocide (which sadly is regular human behaviour). In a slight variation you can make the adherents of religion A leave their island without exception to explore the world around them when the astronomic event happens, but only then. Still make the island taboo for religion B and ensure that the rest of the world is crawling with nasty infectious diseases. [Answer] # It can't be done. I'm going to go out on a limb here and say that this is impossible. Reality is that when a prophet falls from heaven or w/e then often during his lifetime he doesn't even have a religion, just a bunch of followers. The religion forms around the memory of him. Even within a century, the religion will start to fragment and possibly schism into different groups. All of these groups will say they are the true followers and the other groups have fallen into decadence, depravity or heretical beliefs or whatever. Even at this point, the Alien's mate could say "Hahah, your religion has fallen apart, you lose", of course you could counter that they are all your followers regardless of what they say about each other, but it becomes terribly about semantics. Incidentally if anyone wants a good read on the nature of religions, "The Varieties of Religious Experience" by William James is a good read. It's old enough to be public domain. Goes into the nature of saints, orthodoxies, heresies etc. Quite pleasant to read too. In short the religion will start and start to self-destruct at the prophet's death, but it will be a very prolonged and drawn out self-destruct with constant renewal and transformation. But moving on, after 500 years the religion is even more fragmented, both from internal disputes about theology and from geographical dispersion. I believe there are no purely sociological mechanisms to convincingly make a religion self-destruct after a given time. So my real answer is that I believe it can't be done within the constraints of the question. Religions can survive nearly anything, but are constantly transforming making it impossible to pin down when they are "destroyed". **But that's no fun.** Now this is going to be a bit of a stretch, but no more so than some other suggestions. # Unless you cheat. As they say, the only way to be sure is to nuke it from orbit. You would need to position some rocks/iceballs far enough from the sun that they will take 500 years to fall to Earth's orbit - they'll come in with a tidy velocity and cause some serious explosions, but we are aiming more for a light show than total devastation so the rocks should be ~10m in diameter. While orbits are subject to chaos theory, I believe the timing could be accurate enough so the rocks reach Earth's orbit within 500 +/- 5 years. Actually hitting the Earth from that distance would be more of a challenge, but this could be resolved by taking a shotgun approach, place millions of rocks at the correct distance, and perform a massive bombardment of the inner solar system in 500 years. The religion ends in an apocalypse. It's very appropriate. To make sure that the apocalypse is the end of your religion it would be good to include in your sacred texts a passage along the lines "And when fire rains from the sky and it is the end of days, all those who are true believers should fall upon their swords and offer their lives up willingly to me so their immortal souls shall be saved", and then claim that everyone who doesn't kill themselves (or get killed in the bombardment) is not a true believer, because *make no mistake*, religions are hard things to stamp out entirely, so you need to make use of semantics to define when someone is too heretical to count as a member of your religion. I think that positioning a whole bunch of rocks so they take 500 years to fall to the inner system is slightly outside the scope of "Miracles performed by Jesus" but does it count if no-one witnesses it? I suppose some could also argue it's a timing device but we don't really time things by dropping rocks from the Oort cloud. And on the other hand it certainly looks like a natural phenomena so passes that criteria - a rogue swarm of comet fragments passes through the inner solar system. It's not clear our alien has the power to do this, maybe his ship only has enough juice to deliver him to Earth and back, maybe he gets teleported, or only appears as a projection, but anyone who has enough juice for interplanetary travel, teleportation or projection, has enough juice to move a few (million) rocks. Making the bombardment powerful enough to destroy civilization would stretch things too far. Then the religion hasn't self-destructed, instead all the believers have been destroyed by external forces. So this method relies on embedding an instruction in the sacred text that all believers should commit suicide when fire rains from the sky, and then arranging for a whole lot of rocks to fall into Earth's atmosphere so they kill themselves at the right time. [Answer] Starting the religion and getting it going should be the easy part and it doesn't seem like that is really your question. You seem to be more interested in making sure the religion stops in exactly 500 years. Which seems easy enough, you are some sort of half-godly being, judging by the things you have at your disposal. As such, it stands to reason that you have friends/rivals at your disposal with similar capabilities, so simply make a similar bet with one that they can't destroy planet Earth in exactly 500 years. [Answer] Find a suitably impressive and distinctive comet, say, [Hale-Bopp](https://en.wikipedia.org/wiki/Comet_Hale%E2%80%93Bopp). Go back 500 years before said comet will be brilliant (or uniquely identifiable) as seen from Earth. Tell your adherents that you will be waiting for them on a spaceship behind said comet (make sure to be very clear about how they should identify the right comet), and they must shed their human bodies to join you again (ok, make it crystal clear this will be mass suicide). And depending on your definition of "interfering," you might let them catch a glimpse of your spaceship next to the comet. Sound familiar? OK, the end-game is [not exactly original](https://en.wikipedia.org/wiki/Heaven%27s_Gate_%28religious_group%29), but that only proves it can work. Your religion doesn't have to mirror Heaven's Gate at all, except the ending. [Answer] Hubbard and Crowley had such bets about forming religions. If you are as clever as they were, that part is easy enough and doesn't take anywhere near 100 years to get going. Set them a treasure hunt task. Each year on a given date they follow a clue to the location of the next clue. The thrill of following the clues and discovering new 'cosmic secrets' that you have included keeps them hooked. When the 500th clue is found it says: "Haha! you poor saps. This was one big hoax." It goes on to explain in detail how it was all set up and that it was only done for a bet. Note that the treasure hunt does not require special technologies, does not require miracles and does not require interventions. The timing is not specified to the adherents in advance, it just requires them to keep the faith. Therefore it qualifies. [Answer] To all of those saying that a failed prediction would result in the collapse of the religion, I urge you to read [this](https://en.wikipedia.org/wiki/Great_Disappointment). Many of these cults stay in existence after their doomsday passes, so I don't think that would be an effective answer. Once people are pulled into a religion, they will go to any stretch of their imagination to keep from having to deal with reality. I would probably place the cult on a tiny island which has disappeared today due to a volcanic eruption, or a severe earthquake. These events are independent of human behaviour, so the butterfly effect doesn't apply to them. The difference between this and the Pompeii answer is that a tiny island (say a Pacific attoll) is isolated enough to prevent religious spread, and if every one of its inhabitants die, then the culture is lost forever. Also, make one of the tenets of the religion some hatred for keeping records/writing. Prevents conservation and spread even more. [Answer] **Option 1** You can't count on planned ritual suicide because someone is going to chicken out and you've lost your bet. **Option 2** Construct a giant amphitheater that forms the focus of worship. Have the building be built where the whole structure depends on two or three pins engineered to fail when the half-life of one ( or more) ingredients in the pin decays (I'm not a nuclear physicist, so this will be handwavy.) Design the decay time to be 500 years. (You've crazy advanced science, make it happen!) You could also make a slow burning chemical reaction that would destroy the pins strength in 500 years. Engineer the religion so that any member of the religion will be at the amphitheater every year. Make the rituals involve lifting and dropping heavy things on the pins themselves or structures nearby. The concussion of dropped objects will cause the pins to fail, collapsing your structure and winning the bet. **Option 3** Attacks on the verification of the death of all members. How does your alien buddy know who's in your religion or not? If he can't verify then you can't lose. **Option 4** Come back on the 500th year and two days and kill them all yourself in the name of taking the members "to heaven". The religion survived, and the terms only stated you couldn't come back for 500 years, not 500 years and a month. With this option, all you have to do is make the religion survive for 500 years and that's much easier than terminating a religion at exactly 500 years. **Option 5** The rules don't state that you can't contract with alien mercenaries to do the deed at 500 years. [Answer] It really feels like the rules are made precisely to make it as hard as possible. The only way I see to give yourself a chance to win is play on words. > > Start a religion > > > This doesn't mean "start a maximum of 1 religion". Just "start at least one". So I'd give 1 religion to each leader of a family. The religion is centered around an intelligent token (like a necklace) that would work for 100 years.The token can communicate with it's owner. It will teach him rules, makes prediction and makes sure the owner really belives it is a token to communicate with a god. The most important rule is : 1 leader, 1 follower only. The leader is the owner of the token, the follower is (usually) one of his children. This could be enforced by telling him that there's god blood in your veins and others do not have it. All devices could also suggest stability as a safeguard to keep as many religions alive as possible (no killing as it can kill another religion). On the last day of the 100 years, the token gives a powerful prediction : "I shall sleep now, but when I awoken, I'll have the energy to make you (and your ancestors) eternal/a god". Now I just have to hope one of those religions last for exactly 500±5 years. Most religions would probably die out quickly (especially after the 1st 100 years), but some might survive long enough. As long as ONE goes extinct in the expected timeframe, you win. Many answers have issue making sure that "all followers dies", so I went the other way around : "at least 1 follower survives". **Pros :** * No time bomb * No reliance on external factor * No knowledge of futur events required. * No interraction after 100 years **Cons :** * Hard to validate * Is 1 follower enough to be called a religion? * No predefined self-destruction (oops) [Answer] ### Mathematical trickery and laugh: Each year on the shortest day your followers throw the holy dice and interpret the results according to the holy bible. And when the time is ready this ritual will show gods true face. So you write a book with some complex encryption and have a range of dice with strange symbols. Each year they will get a result like "The time is not ready, remove the red die" so that after 500 iterations no matter what they rolled they will finally get the result: > > "You clumsy idiots practised this scam for hundreds of years? seriously? how dumb can one be: There is no higher message, I was just good at maths and you ancestors were pretty gullible" > > > Since there are many parlour tricks like "imagine a number, divide it by 3, add the result... whatever" which result in the same final number, whatever your choice is, you can surely construct such a thing, that after 500 iterations and looking in the book they will get the message. [Answer] **Drop a freaking meteor on their heads.** You're a super advanced alien with space travel being no big deal right. Start your religion, make it in some geographically isolated location (islands are ideal, but with low enough tech levels for humans many places could work). Designate that site as holy and the only home for true believers who do not want to be "corrupted" or something. Leave planet earth. Use your advanced technologies to launch a meteor through space and impact the site 500 years from the start date of the bet. [Answer] I would go Easter Island in the year 1368 and convince the Rapa Nui people that we were gods, and then proceed in building the moai and start a cult that worshiped them. I would then destroy any other religious artifacts, burn books if they exist, etc. This will only leave my religion. I would then destroy any means of them leaving the island and watch over it for the 100 years I am allowed to be there and proactively prevent outside contact. I would also use my advanced knowledge to stop other cultures from getting access to the island until 1722 when the Dutch discovered the island. Since I would have left Earth after 100 years, I would go around the world before then and create riddles, hoaxes, etc. to steer everyone off course from the island until the early 18th Century. Once this island is known in Europe, there will be a chain reaction which will wipe out nearly every inhabitant. The last of the survivors will have been converted to Roman Catholicism in 1868. Since this island is being settled by European missionaries, there is no chance that my religion would be accepted by them. Since the island would be completely isolated, the religion would not spread beyond the confines of the island, and will be extinct after 500 years. [Answer] Create an inner circle for the religion who are well aware that is is a hoax, however get them to go along with it by the fact they get money/girls/whatever. Make it very clear to the inner circle that they need to end the party at the correct date and how they should create two new religions, fake a schism, and then cause the believers of the original religion to all fall into one of the two new ones. If they don't do that you will return and be very unhappy with them... (It doesn't matter which new one they join, the important thing is that they leave the original. The new ones are different enough in some central tenant that they qualify as a new religion). [Answer] While I must direct most of my attention elsewhere for a while I shall return. My return will be seen by all as a bright light in the constellation of <some constellation>, then I will return to our temples. If I do not show, know that I have met my demise. Now, you being an alien with FTL know about a supernova that will become visible to Earth 500 years from now. The light will appear, the "god" won't show. [Answer] I don't think it's actually possible to create a religion that ends in 500 years without involving something other than the religion and a randomized followers... Sorry, but here's some possible loopholes? --- I could set a cult in the Tunguska forest and have them all die via Tunguska Airburst... Or a mining project to an underground volcano that takes 500 years to kill them... Or have them do innocuous things that insure they make predators that'll kill them in 500 years... The followers will stay in the area by saying that they're Ex-communicated if they leave! Or contained by death threats, giant walls, pit traps, or something else... Perhaps predators... --- Last brainstorm: Get a group of people genetically predisposed to dying early and those predispositions have a phenotypical signature, or something, and make a religion about having two groups breeding every so and so years, such that after 500/so and so years generations, you have a kid that dies on the 500th year of your religion... [Answer] Spend 100 years finding: 1. A perfect spot for your followers that will cut them off from the rest of the world for at least 500 years. 2. A set of people with DNA that will essentially doom them in 500 years due to cancers and/or genetic diseases. 3. Specific rules about reproduction as a backup to ensure #2 happens accurately and timely, as well as rules about detecting "dangerous mutations" - things that would prevent the last generation from dying on cue. 4. Dangerous situation outside the location that will kill anyone attempting to enter or leave. 5. Enough technology that they will have to work for their food and entertainment, but not very hard - starting a new colony just a few miles away would be terribly difficult, even if one overcomes the dangers. Not so much that they would become idle and hasten their death. Then spend the next 400 years finding someone to take your spot if you lose the bet. [Answer] 1.) Start your religion or cult in 1383 on a small island called Krakatoa. Tell your followers leaving the island is sin. 2.) Wait 500 years... 3.) Done! [Answer] I have to agree with [@BlakeWalsh's answer](https://worldbuilding.stackexchange.com/a/20317/2138) that **it can't be done**, *at least not with certainty* - but I'm going to focus on the constraints of the problem which make it this way. > > Bet conditions prohibit you from actually specifying 500 years anywhere in the content of your religion. Or any specific dates 500 years in advance. > > > Bet conditions prohibit you from interfering IN ANY WAY with that religion beyond initial 100 years. > > > you can't leave a miracle generator with 500 year battery, and predicate the religion on miracles keeping coming. > > > ALL your miracles must expire in the 100 year period - no verifiable trace of them should be left once you leave earth except hearsay or naturally-looking consequences. > > > You have approximate knowledge of how Earth history went in that entire time period, meaning you can engineer your religion and your timings to co-incide with major trends. > > > BUT, you have only approximate knowledge (because of butterfly effect, or because your psychohistorical formulas have a large error margin, whatever) - Columbus may have sailed to New World in 1492, OR in 1481, OR in 1511 > > > --- So, we need to be able to come up with a date at which either something catastrophic happens to our followers, or at which something happens that proves the religion is undeniably unable to be followed. However, we cannot specify a date. We can't leave *anything* with proof of us having ever existed, and we can't rely on our knowledge of history well enough to rely on any event happening on a certain day - even with the 5 year lee-way. This means we have three uncertain options: *Disclaimer: links do not cover all answers, nor will I update them to include new answers, many answers cover more than one category* 1. **Rely on uncertain dates, gambling with the [intended spirit of the] butterfly effect** * [Samuel's answer](https://worldbuilding.stackexchange.com/a/20273/2138) * [Kevin's answer](https://worldbuilding.stackexchange.com/a/20291/2138) * [Wrzlprmft's first answer](https://worldbuilding.stackexchange.com/a/20341/2138) * [JasonHutchinson's answer](https://worldbuilding.stackexchange.com/a/20338/2138) * [EvilFonti's answer](https://worldbuilding.stackexchange.com/a/20482/2138) * [Alex's answer](https://worldbuilding.stackexchange.com/a/20401/2138) 2. **Rely on *gray area* solutions** - those which would work, but depending on your interpretation of the [intended spirit of the] rules. * [Theik's answer](https://worldbuilding.stackexchange.com/a/20305/2138) * [BlakeWalsh's answer](https://worldbuilding.stackexchange.com/a/20317/2138) * [chaslyfromUK's answer](https://worldbuilding.stackexchange.com/a/20274/2138) * [James's answer](https://worldbuilding.stackexchange.com/a/20337/2138) * [Lolorz12's answer](https://worldbuilding.stackexchange.com/a/20463/2138) 3. **Rely on your teachings to be followed to the letter without changing** - a lot of these answers also depend on the definition of how a religion "ends", but humans will adapt things to fit their own needs and situation - or simply ignore those parts which goes against what they *really* believe in their religion. Whether the changes make it a "new" religion or not is debatable. * [Wrzlprmft's second answer](https://worldbuilding.stackexchange.com/a/20367/2138) * [Falco's answer](https://worldbuilding.stackexchange.com/a/20313/2138) * [LorenPechtel's answer](https://worldbuilding.stackexchange.com/a/20281/2138) [Answer] During your miracle days, create a special food that is very nutritious. Let's say a GMO plant of some sort. After a while, people will reverse engeneer it and say it's science. This food should also be part of a very important ritual that needs to be taken. In that plant, have a gene that terminate it after 500 years (or x generations) when everyone is addicted to it. The plant could also slowly render to population sterile and after x generation of human, they all end up babyless. [Answer] I'm not sure if this is within the limits of "modest miracles" but here's my shot: I'd send an alien specimen that reproduces after 100 years of life and dies after that. They would be my priest, and I'd send a curse (behind the curtains) to the first alien where his fifth son would not exist or have some sort of lycantropy where he chases down every remaining follower of the cult (maybe they'll identify themselves with something wearable). I think Blake Walsh's answer is the most adequate one though. [Answer] The only solution to eradicate a religion appears to be the extermination of all believers, followed by *damnatio memoriae*. You would need to set up the main religion in a geographically isolated place. Then you would need to set up a splinter assassin's creed ruled by astronomical events. A firm belief on being the True Chosen and rewards for unthinking, unquestioning fanaticism would be required, but history proves that's the easy part. The main belief would, on the contrary, foster peace and harmlessness, teach fatalism and acceptance. On the appointed day, Religion A's followers are slaughtered, their temples destroyed, and their sacred texts burned. You did bet you would have one religion last 500 years... you said nothing about a second, radically different one. But on a closed and isolated ecosystem, you could also have exterminated all pollinating insects and otherwise ensured the main dietary staple could never survive without religion A's secret fertility rituals. While Religion B's followers would only survive on the tithes given by the followers of Religion A, tilling the earth being forbidden to them. So when they exterminate the followers of Cain, the followers of Abel also commit racial suicide. [Answer] Go to Hiroshima/Nagasaki ~500 years before the end of World War 2(i.e. nuclear bombs destroy these cities). Locate a well-established family living in or around the center of the city and establish your religion with them. Your religion should have the following principles: 1. I have chosen you and your direct descendants as my disciples; no others are permitted to know of this following in any way. 2. Your family household is sacred; you must never leave your household or the city of Hiroshima/Nagasaki. In addition, the architecture itself is sacred and you must never add any additional rooms to your household. As long as you stay within your walls in times of trouble, I will protect you. 3. If you break my commandments, you and your descendants shall be cursed for eternity(here perform a minor "miracle" that shows you are capable of such a thing; cause someone to whiter away, etc.). Establish any other laws necessary to flesh out the religion(make sure there's nothing too terribly demanding). Do whatever is necessary to ensure that their faith is well-established and long-lived. Interfere with the local government in an indirect way to ensure that their family estate is left untouched over time, and that they are well-provided-for. This way their descendants after the 100-year mark will know that their god is taking care of them. In particular, make sure that no one from that family is ever subject to being drafted into the army(if they were, they could potentially survive WWII, meet a spouse overseas, etc.). Even with the margin of error inherent in your timeline prediction system, the destruction of Hiroshima and Nagasaki at some point during WWII is virtually guaranteed, and WWII itself is too big an event for your predictions to get too far off the mark. Commandment #2 will ensure that no bomb shelters are built under your cult's household. Your tiny religion will survive in secret within one Japanese family, then die out when that family is killed by the nuclear strike. If by some chance any members survive, they would be unlikely to keep faith in a religion that allowed such a horrible thing to happen to their "sacred" household. You could even use your advanced alien technology to engineer something in the house to react with the nuclear weapon that would present a clear message to any survivors(a cross burned into the foundation, rubble arranged in a star of David, etc.) All this is assuming that you can establish that level of faith in a small group of people, but if you can't do that then your bet is lost before it begins. [Answer] I like the cicadas' solution by Wrzlprmft. The basic idea is to genetically alter cicadas into breeds whose adults emerge at regular time intervals that match up all breeds after 500 years. That idea is brilliant, but I thought up some detail improvements: * **How to keep people from seeing cicadas as threat?** - Tell them the cicadas aren't eating the food for themselves but bringing it to the promised land. That's also perfect reasoning, why food storage is disallowed: The cicadas can't bring it to promised land, if you do. You'll be stealing it from your ancestors and your future self, if you stop them taking it. * **How to control the numbers of cicadas so people really don't notice?** - Have a predator that only eats adult cicadas and other insects. The predators will have a steady supply of cicadas as the breeds don't align. The steady supply will keep the predator population increasing slowly together with the perceived growth of cicada populations. Without the predators the cicada populations would actually grow exponentially. * **How to get rid of the predators before ultimate doomsday?** - Note that the maximum distance between two populations is (shortest breed) years. This maximum distance will actually occur right before doomsday. Plus, there are (number of breeds) populations that are close together before doomsday, i.e. 20 years vs. 1 year between 479 (21-year brood in t-1) and 480 (20-year brood in t-1). The closely aligned populations will cause an increase in predator population. This will mask the exponential growth of cicada population. In the next 20 years the predators will starve. * **How to make sure you get rid of predators for doomsday?** Tell your believers to watch out for the rapid growth in predator population. Instruct them to root out the predators, if that happens. Also instruct them, to wait as long as possible, because they **will** trigger a war of cicadas vs. predators and the promised land needs to be prepared for this war. About 15 years into the war many cicadas will come and so will you to take your people to promised land on the back of giant cicadas. * **Why that part with 15 years?** Your people will be waiting as long as 20 years for the cicadas to come. If you don't predict a time (and anything fails) they fall from belief too early. After all an important thing of their cult is missing for one of their own generations. If they do after 14 years of waiting, you'll be in a pinch. After 15 years you'll still be safe. However if you say 20 their faith might be strengthened by the perfect match in your prophecy. Even if they start wondering after 15 years, they'll only be devastated when after 5 more years everything blows over with no (promised) land in sight. * **Wait, how long does it take to fall from belief?** Start at least one year early. Your people will lose all their food during summer, when the cicadas come. Even with most of the food gone they will survive for some time from roots and stuff the cicadas didn't eat. Most of them will starve at the end of next winter, when really every bit is gone and nothing has grown back yet. That's about half a year. Give them some time to get desperate enough to fall from belief. Plus, there are 20 years to come with no cicada fetching food or carrying them to promised land. Let that add to the desperation, if doomsday didn't work out. You got still 5+x years left of safety to observe and find a way to cheat, if needed. ]

[Question] [ Imagine that the inhabitants of Earth all follow a religion that allows only wooden weapons. How would warfare look nowadays? > > **Commandment 37.** > > > 37a) Thou shalt make weapons only from the wood of trees that grow in > the forests. No weapons of metal or other substances shalt thou make. > > > 37b) No part of thy weapon shall be made of anything other than wood, > nay, not even the smallest part thereof. > > > 37c) No other device shall be used to project such weapons towards thy > enemy unless that device shall also be made entirely of wood as > heretofore prescribed. > > > **Commandment 38.** > > > 38a) Thou shalt fight and defend thyself entirely naked excepting for > a loincloth to protect thy modesty. This shall extend at most from thy waist, down to thy upper thighs and shall be made entirely of wool or cotton. > > > 38b) No movable shield shalt thou > have but thou mayest hide behind immovable objects. > > > **Question** Given these restriction but all other technology being as it is today, how sophisticated could weapons and warfare actually be? What would the most advanced weapons look like? What current scientific knowledge could we use to make them as deadly as possible? **Notes** 1. Even bows and arrows would be prohibited unless every part of them is made of wood. That includes the bow 'string' and the arrow heads. 2. Any type of wood that grows 'in the forests' on our current Earth can be used. 3. There is no cheating. God sends down a thunderbolt and kills anyone who disobeys. EDIT in response to comments. 4. Modern day priests have decreed that 'wood' means any part of a tree including the leaves and roots. God seems to have accepted this because no-one is getting blasted for it. A tree is a non-genetically-modified plant that naturally grows with a single trunk and has grown to a height of 20 feet or more. Priests actually ensure that weapon trees are over 25 feet in height to avoid errors. 5. God is omniscient so you cannot cheat. You could make a metal weapon and hang it on the wall. **As soon as anyone touches it with the intention of using it as a weapon they will be struck down.** 6. Fire is allowed during battle as long as all flammable products come from trees. 7. It must stay as 'wood' until battle is in progress. You can extract and use natural organic products (such as sap) however, you cannot use industrial processes to extract metals from the wood for example. 8. It must be cut/harvested from a living tree so fossilised wood and rotten wood are disallowed. [Answer] Pitch is technically a forest product. And you can set it on fire--fire's not a material. And then you can toss it at the opposing army with trebuchets. And they will all burn, horribly. And your god will be pleased. [Answer] Sounds like what neolithic tribes have in the Amazon rainforest (minus the stone tips for the spears and arrows). The limits on materials and armour strongly constrain the ways people could fight and the tactics that would be available as well. Most weaponry would be muscle powered, which would limit the size of the weapons, the forces that could be applied and the length of time that fighting could be possible (even highly conditioned warriors would probably run out of energy to fight after about 30 min of actual combat). Striking weapons would be variations of clubs, using the densest wood possible and carefully selecting the wood for straight grain and lack of flaws before carefully curing it. Clubs might evolve into something resembling a *bokken* (wooden training katana) once it is realized that focusing the force of the blow onto an edge (even a rounded edge) is far more effective than a round or flat surface. This could be complimented by thrusting weapons like spears and pikes, and ancient armies used pike formations to anchor their positions, disrupt cavalry and "push" through the opposition, if possible. Against unarmoured opponents, this would be ridiculously easy. Distance weapons could be bows, crossbows or javelins. Javelins might be highly effective when boosted by an *Atlatl*, which provides extra leverage to the throwing arm. Once again, these would be highly effective against unarmoured opponents. Since using protection is prohibited, I will skip the idea that a forest of raised pikes could deflect "plunging" fire from arrows, spears and javelins, since this sounds like something that would be more of a theological debate than a tactical one. Since all fighters are unarmoured, and effective long range weapons do exist, then people will have to fight in "open" formation (close packed ranks would simply be mowed down by arrows and spears). This would give rise to a culture where fighting is done by individual "champions", and a battle would resemble the Homeric vision of a series of individual duels between heroes of roughly equal rank. A battle might start with a ritualized series of "challenges", where men stride forward and call out their names and achievements. Once an acceptable pairing has been selected, they start by throwing spears or firing arrows, then, when the weapons run out, close in for stick fighting. If the sticks break, they may end up grappling on the ground. Depending on other social factors, this does not mean a series of individual duels, but many fights can take place simultaneously. Social mores would also limit this form of fighting; unknowns would not be able to challenge the champion, and a form of "rank" based on achievement would come into effect. There would also have to be some system of visible rank, a token of some sort that can be stripped from the dead body to prove that you were the victor of the fight. This would also have consequences for society, since fighters would have to essentially train full time to become effective, and therefore not be involved in crafts, farming or trade. A feudal social order would prevail, enforced by the fighting men themselves (who would oppose them?). This social structure might also limit the growth of technology, since while wooden catapults or trebuchets may be possible, tight formations would not exist, and individual warriors would be horrified at the thought of being crushed by a log flung from a trebuchet several hundred metres away. [Answer] So, you're only allowed to use weapons made from trees, and if you want to try to kill an attacker who is trying to kill you, you will both be effectively naked. Given such restrictive laws of combat, I will presume that the [Hague Conventions on warfare (in particular the 1907 convention)](https://en.wikipedia.org/wiki/Hague_Conventions_of_1899_and_1907) do not apply. What we have here is a situation where personal weapons will either be melee-style objects or missile weapons, but this does not preclude heavier weapons. Also, while the commandments - and God - enforce the rules against the use of non-wooden weapons in combat, the commandments do not specify that *non*-wooden objects may not be used to *produce* the entirely wooden weapons, so long at the tools are not used as weapons themselves, and do not remain as *part* of the weapons in any detectable amount. This means that aside from combat, we have the full range of modern human technology with which we can *prepare* our weapons. **Melee Weapons** Timber may be used to produce spears, clubs and maces, and with lamination using tree-based resins plus heat treatment, may be used to produce cutting blades which, while not as sharp as a metal knife, are sharp enough for use against combatants who *must* be effectively unarmoured. These weapons may be anointed with tree-based toxins. Since shields are prohibited, dual-weapon use may be common, with one weapon being used to attack while the other is used to defend. Since the use of each weapon is interchangeable, and each may be used to both attack and defend as opposed to being primarily defensive as in a shield, this should be permissible. **Missile Weapons** With the application of technology, there are a number of missile weapon systems that can be made using no materials other than those found in trees of varying species, those being bows, crossbows and blowguns. What may have begun as a simple self-bow could through the ages have evolved into a longbow, a recurved bow and even a modern compound bow. Timber could be laminated using tree-based resins to maximise strength and springiness. From the bow we can derive the crossbow. The lock mechanism would need to be strong, but could be made using laminated wood, and the bow is just a bow mounted on the stock. Given that combatants *must not* wear armour, the blowgun becomes an effective weapon. This is a simple wooden tube through which a sliver of hardwood wrapped in a tree-based fibre can be blown. All of these missile weapons can be anointed with one - or more - of a number of tree-based toxic substances. **Heavy Weapons** Trees can supply timbers which may be used to build [trebuchets](https://en.wikipedia.org/wiki/Trebuchet) and other [catapults](https://en.wikipedia.org/wiki/Catapult). The counterweight of a trebuchet may be of the hinged-counterweight type with the counterweight bucket filled with wood, or using [tree-derived rubber](https://en.wikipedia.org/wiki/Natural_rubber) as an energy store, and being used to propel logs or wooden spheres which may be solid or hollow and filled with a variety of interesting tree-based toxins or tree-derived flammable oils. **Toxins** The following are tree-derived toxins which may be used to enhance the lethality of the tree-based melee and missile weapons: * [Curare](https://en.wikipedia.org/wiki/Curare), which is a fast-acting arrow poison that may be derived from certain trees. * Cerberin, a poison derived from the [Suicide Tree, Cerbera odollam](https://en.wikipedia.org/wiki/Cerbera_odollam), which if injected should act quite quickly to cause cardiac failure. * The [Manchineel tree, Hippomane mancinella](https://en.wikipedia.org/wiki/Manchineel), the fruits of which contain [Physostigmine](https://en.wikipedia.org/wiki/Physostigmine). * The [Castor Oil Plant, Ricinus communis](https://en.wikipedia.org/wiki/Ricinus) which in certain conditions may grow as a small tree which fits the required criteria, and which produces [Ricin](https://en.wikipedia.org/wiki/Ricin), a potent toxin that kills slowly and painfully. * The [Strychnine tree, Strychnos nux-vomica](https://en.wikipedia.org/wiki/Strychnos_nux-vomica), which produces [Strychnine](https://en.wikipedia.org/wiki/Strychnine), a toxin producing convulsions which lead to death. **Weapons of Mass Destruction** Ricin and some other toxins are effective as a toxin when powdered and distributed in the air, meaning that they could be used effectively if thrown from a catapult or trebuchet or other aerial source. This would constitute a WMD in that it is the employment of a poison over a large area, intended to affect multiple combatants. **Ships** It is certainly not out of the question for a sail-powered ship to be made from timber, and rigged with tree-derived sails and rigging or aerofoils. Ships may carry heavy tree-based weapons, particularly tree-oil-based fire ordinance for use against other warships. **Aircraft** A glider can be made entirely from tree-derived materials, with natural or laminated timber spars and ribs, with tree-based ropes connecting the controls to the control surfaces, and using tree-fibre cloth to cover the airframe. Gliders may be launched from high places or using natural rubber catapults, and can climb using thermals and dynamic soaring. Once airborne, a glider can drop tree-based weapons on combatants below, including wooden shot or darts which would be effective against helmetless combatants, or they could distribute powdered tree-derived toxins or tree-oil-based fire weapons. A glider may also carry a tree-derived stored-energy missile weapon similar to a ballista for use against other gliders. It may achieve multiple shots if loaded by non-pilot crew members. Our gliders may also have a natural-rubber "engine" and a wooden propeller, a thick bundle of rubber strands connected to the propeller and the rear of the aircraft, which is wound tightly prior to launch, and released in the event that a bit of extra thrust is required, providing a few minutes of additional power. So, as we can see, trees can produce - or be *used* to produce - all sorts of interesting and deadly things. **Camouflage** This is a *little* iffy, but combatants may be able to wear camouflage body paint and a camouflage loincloth, as it does not count as a shield, and body paint is technically only a stain on the skin, such as may otherwise be acquired during the course of combat. It is not physical protection, nor does it provide much more modesty than a loincloth. **Communications** Is a cell-phone or radio - used in combat for communication only - a weapon? As long as you don't try to physically hit an enemy with it - or hide behind it - you should be safe. **Optics** As an extension of the communication angle, if not used to cause an enemy physical harm *directly*, it may be permissible for combatants to carry optical devices such as binoculars or night-vision gear. [Answer] Since you mention that water, and air, are okay with the designs of the weapon - *Compressed Air* could be a major source of energy for most weapons. You would essentially have "guns" - but it would work more like highly-powered blow darts. There could even be a magazine full of wooden bullets for automatic weapons. The bulkiest part of the weapon would be the container for the air. I assume the wood would have to be quite thick, therefore quite heavy. **Edit**: Being able to use rubber would make things much easier and possibly not as heavy. [Answer] > > God is omniscient so you cannot cheat. You could make a metal weapon and hang it on the wall. As soon as anyone touches it up with the intention of using it as a weapon they will be struck down. > > > Given likely aspects of the nature of this Wood-God, the what-if Weapon systems *could* be more sophisticated and destructive than contemporary weapons systems, as *might* the conduct of warfare. Nearly all weapons would be remote-guided (drones) or self-directing, and due to the social costs of production, deployment and use of these weapon systems, the use-case of the weapon systems would be preemptive massive first strike. ## They would include wood only as an incidental component. Thousands of years of Wood-God smiting of would-be weapon designers instructs us that one can craft a forbidden weapon, but not touch it with intent to use it as a weapon. It also informs us to the degree of involvement and intentionality that is permissible, and that which leads to smiting. Wood-society, mindful of the permissible boundaries, compartmentalizes the logistics, construction, testing, and deployment and use of the weapon systems. At the core of this society-wide project would be several strictly cloistered groups, raised (now) for generations, with the lack of intentionality that their actions would be responsible for use of the (unknown to them) weapon systems. Depending on the past-examples of Wood-God's smiting, some of these people might be killed by their actions, but they would never know this beforehand. When the attack order is given, cloistered-Johnny pushes a button as ordered/plays his video game/flies his plane to the destination to 'drop food' etc. all with consequences innocently unintended by Johnny. Warfare would be massively violent, because of the cost of maintaining the 'cloisters' and the potential of being wiped out by the enemy. Obviously I prefaced my argument with a premise of the likely nature of Wood-God. * p1 Wood-God doesn't outlaw warfare. * p2 Wood-God permits metal weapons to be constructed, but only smites those who touch the weapon with intent to use it. * C1 Warfare is permissible. * C2 Smiting is the consequence of intent, not the consequence of action. * C2.1 People, to some degree, can build weapon systems components without being smited. * C2.2 People can use weapons systems components without being smited, to the degree that they know not what they do. \*\*\* I find it likely that there would be no warfare or weapon systems given the societal conditions (clear proof of the existence of Wood-God; a single religion) and posit a unitary global theocracy as the end-state of such a society, therefore with no need for warfare, but am mindful of the schisms within Judaism, Christianity and Islam. Warfare would have been wood-centric until the point where social engineering of the 'cloistered' class AND something along the lines of atomic weapons collide: The group possessing both would rapidly and completely dominate. ## \*\*\* In retrospect, some credit given to TrangOui - I'm giving the same idea, expanded. I don't have enough Reputation to comment. Reply to Chassly's 2nd comment on Wood-God's omniscience (and the Problem of Evil) I did read Rule 5 carefully (enough to include it as the header of my conjecture). Unless I am misreading or mis-reasoning, Wood-God doesn't smite unless: * a) There is knowledge of, and intent to use, a prohibited weapon. * b) The person must actually touch the weapon with intent to use the weapon. Before going into the details of my conjecture, let's both recognize that the weapon-systems-designers of this world know the actions that are and are not permitted by Wood-God and are capable of crafting a causal chain which would permit the use of (say) nuclear weapons. * If a) is not the case then the weapon-maker making the metal weapon would have been smited at some point before the weapon was affixed to the wall, as she is touching the weapon while making-or-mounting the weapon, knowing it is a forbidden weapon, though she has no intent of using the weapon. HOWEVER, she does make the forbidden weapon, knowing that it is *possible* that someone may try to use it. She is not smited, even knowing that she made a prohibited weapon. Similarly the wall-maker was not smited for making a wall - either with knowledge of it being instrumental as a mounting piece for a weapon, or without any idea. Also that of the miners and smelters who sourced the ore and fashioned it into metal for the weapon-maker to make - either they had no knowledge, intent, or are far enough back in the causality chain to prevent their deaths. So Wood-God doesn't punish the people involved in the chain-of-conspiracy to make a forbidden weapon available for use (deployment). * If b) is not the case then the warrior who touches the metal weapon on the wall might as well have been killed before touching the weapon, as their intent to use the prohibited weapon is manifest BEFORE the action (touching the weapon) is taken. The weapon-maker had intent to make a prohibited weapon, and took action to make the prohibited weapon, but (obviously) was not smited (because the weapon was made). The warrior was not smited until touching the weapon. If your concern is that the commander ordering Johnny 'touches' Johnny with sound waves, due to a verbal command, the commander might easily just write Johnny a letter, send Johnny a text message, or decades earlier during Johnny's cloistered training merely say 'when this light flashes red, press the red button'. Wood (pun intended) the Wood God smite the commander as soon as she touched pen to paper, or only immediately before the letter is mailed? Would Wood-God permit the text message to be composed but not sent, or smite the commander before she touched her smartphone? Would the commander be smited decades before, before she gives Johnny the order to press the red button when the red light flashes? If not, then the message gets through and Johnny presses a button, and the forbidden weapons get used. Finally, Wood-God's omniscience is not a *deus ex machina* to bolster your argument that 'this couldn't happen'. IF Wood-God didn't account for the intent AND action of human beings (usually called 'free will') then the weapon-maker dies before the metal weapon is made, the warrior dies before the weapon is touched, and the commander dies before even doing anything but thinking about commiting the act of using a prohibited weapon. Pity also the wall-makers, miners and smelters who would otherwise die knowing that their ore, metal and walls MIGHT be used to make or mount a weapon. I thought while composing my first post: This discussion becomes more a consideration of the Nature of God (where does God's accountability end and Free will begin?) and the Nature of People (when is bad actually broken?) than the inventiveness of wood-bound-warriors. To obviate any future challenge on the 'cheating' aspect, I'll illustrate a causal chain where a forbidden weapon is made and used, and Chasly can reply as to where someone is smited. ## Weapon Construction I think that Weapon's makers are free from smiting, based on the previous example. 1. Albert comes up with the Theory of Relativity 2. Beth designs a functional missile for delivering mail across the world. 3. Charlie starts a company mining and refining uranium. 4. Deena constructs Beth's missile. 5. Evan applies Albert's theory and Charlie's uranium and constructs a power plant to make nuclear energy. 6. Fanny improves Evan's process and fuels the plant with plutonium. 7. George discovers that shaped explosives are much more effective for demolishing buildings. 8. Heidi theorizes that Fanny's plutonium and George's explosives could create a very powerful explosion, useful for creating large underground caverns, detonating rogue asteroids threatening Earth, or, when used in series, propel spaceships. 9. Ichabod constructs a device based on Heidi's theory, and mounts it to one of Deena's missiles to defend the planet from a rogue asteroid. 10. Jody realizes that Icabod's asteroid-destroyers could be used as a weapon, and advises Ichabod to make a few changes to it to prevent this weaponization. 11. Ichabod does not make the changes to the asteroid destroyer. 12. Krauss changes Ichabod's asteroid destroyer into an ICBM, now useful as both a weapon and a monster-killer, assuming that monsters were to ever appear. 13. Lilly removes the monster-killer modifications yielding Krauss's ICBM as purely a weapon. ## Weapons Use 1. Alma is a religious zealot and historian who starts an Order which carefully documents what is and isn't permitted to Wood God's law. 2. Barry is a wealthy-but-eccentric man who starts a perfectly-isolated community where the residents know nothing about weapons use and are trained in Alma's law except they are ALSO trained to press buttons corresponding to lights (green button, green light), and (several generations later) see this as a religious duty to Wood God, because that's what they've always been taught. 3. Connie, another Wood-God zealot develops an early warning system which tells the wood-armed troops when and where the enemy moves. There is a red light when the enemy is detected. She abhors the use of any prohibited weapons and creates this system specifically to aid the legal use of wood-armed-troops. 4. Donny realizes that Connie's system could be joined to Lilly's (above) ICBM's. 5. Donny tells Eunice to create a system that joins Connie's EWS to the targeting systems of Lilly's ICBMs. Eunice is lied to and thinks she is making a more efficient asteroid killer. 6. Donny tells Fred to create a system to launch Lilly's ICBMs, targeted by Connie's EWS with Eunice's improvements, at the touch of a button. Fred is lied to and thinks that he is making a more responsive asteroid killer. 7. Donny tells Gina that he has a fully functional weapon system, and at the next enemy movement tries to press the button. If Donny lives to press the button and then ultimately dies, the enemy is still killed. If Donny doesn't live to press the button ... 8. Gina brings Fred's button to Barry's commune. She paints it red to match the red light on Connie's EWS. 9. Harry and Indira call off sick. During Johnny's shift the red light blinks and Johnny presses the red button. Who does God smite, when and why? Albert and Alma kick off the entire causal chain, without them, from Beth and Barry to Johnny and Lilly, none of the others would have been at risk of being smited. I didn't formulate this conjecture as a formal proof (because it's already deep in TL;DR territory) but I expect the principal of Charity to be applied, and a clearer understanding of When Wood-God Smites. [Answer] The primary weapon would be **fists**. You can't use wood at all, because your opponent will just throw sticky cloth at your weapon, and now your all-wood weapon is partially *not*-wood, and using it will get you killed. So basically, warfare would just be **giant brawls**. [Answer] Limiting weapons to use only wood, and not using any industrial process to produce a weapon, you're really just left with tactics. I can imagine warfare consisting of lots of traps rather than hand-hand combat. Assuming a hole in the ground doesn't count as a weapon, you can cover it with leaves and branches with spiked sticks below. The fall wouldn't kill you, the sharp sticks would. In tight corridors, you could roll a large log down towards the enemy (think Indiana Jones running from the large boulder). Seeing that leaves and roots count, you can use thin/fragile roots as trip wires, once breaking causing a large log, which will be held up from a tree with thicker/stronger roots, to fall and crush someone. [Answer] If making suitable bow strings is an issue can I suggest the Spear Thrower? <https://en.wikipedia.org/wiki/Spear-thrower> They can be made simply and pre-date the bow as a hunting weapon and are still used in some cultures. They and their ammunition can be made from wood and would be simple to mass produce and in the world you describe they would make a useful weapon especially for light cavalry or skirmishers. [Answer] Cultivate and weaponize [Dendrocnide excelsa](https://en.wikipedia.org/wiki/Dendrocnide_excelsa) as the main "blade" part of spears, arrows, swords, etc. (so the shaft of the spear is something like elm, the head of the spear is Dendrocnide stems and/or leaves) the nettle tree (and many of it's relatives) is native to areas around Australia. Alternatively, it reads like the branch/trunk stuff is safe so I suppose just cut a fresh branch and smack people with the leaves. The stinging parts exist on "all aerial parts" of the plant; which a separate website handily defined as all leaves, flowers, and stems. The stings of such plants are said to be extremely painful for days to weeks (or even months in some cases), the pain has reportedly driven horses off of cliffs. I know that burning something like poison ivy produces a sort of irritating and dangerous toxic smoke (but I won't try to weaponize poison ivy since it is not a tree) however burning the leaves, etc. here may produce a similar toxic cloud that could be launched via trebuchet toward thy foe (though I can't seem to confirm this, so this bit is speculation). A very effective chemical weapon in tree form (make sure you're careful with handling). [Answer] # Suicide bombers These people would be in huge demand, and their price would be high. **Suicide bombers would sacrifice their life for religion or to make their family millionaires.** (Religious wars would likely still exist, as every major religion has sects). They will go to their chosen destination, find explosives, and press a button as they are struck down by lightning. The only way to stop them is to prevent these bombers is to: 1. Stop the bomber and/or their weapon from reaching their target location 2. Stop the construction of these weapons. Governments will attempt to track and stop the building of these weapons just as we treat nuclear bombs today Furthermore, I don't see it unreasonable to find guards carrying non-wooden weapons, willing to sacrifice their life if a high-profile person's life is in danger. They will spend years training their minds such that they do not consider using their weapon as a weapon until the time of need arrives. [Answer] Why reinvent the wheel? There are a lot of really scary trees that exist without genetic modification. Potential warmongers could try to figure out a way of using the [dynamite tree](https://en.wikipedia.org/wiki/Hura_crepitans), whose fruit literally explodes. Well they'd probably be treated much like any other highly volatile explosive. Think like a grenade that was as unstable as nitroglycerin. My guess is stuff like refrigeration could potentially let an army store munitions. It apparently also has caustic sap that can poison the other naturally occurring spikes. So if all else fails, you still have a very unpleasant chemical weapon in the sap. Some trees are already weapons. [Answer] **I wouldn't make wooden weapons, I would train elephants.** They're not weapons, they're my mount. And I certainly didn't make them. And they're not using non-wooden constructed weapons (unless you train them to club people with trees... Which is probably better than a man with a sharp stick). Lions, wolves, tigers, horses, bulls - all fine alternatives. [Answer] Some tree barks can be used to make rope/string. So bows are back in the mix. On top of that using rope will add in catapults, Ballista, and Trebuchets. Of course you can't throw rocks, but plenty of things can be created to throw. Arrows won't really need metal or stone points if shields and armor are not allowed. They were really added for penetration depth through other layers. Poison. Different trees have different substances that can be used to dip arrows and spears into, or anything else (like a load of caltrops made from wood) One tree is very poisonous the [manchineel](http://knowledgenuts.com/2014/01/24/the-tree-so-deadly-it-was-used-as-a-torture-instrument/) could be used to for poison darts and arrows. It was actually used for this in the past. OOH, and of course the most important part would be to put non-wood items into enemies weapons, thus they would be destroyed, when they try to use the weapon! [Answer] Since we've already stated that we have the full technological advances of today's world available to us, we can build a kinetic orbital bombardment weapon [(one idea location)](http://www.nytimes.com/2006/12/10/magazine/10section3a.t-9.html?_r=0). Obviously we would need a rocket to get the weapon to space. According to the rules set, moving a weapon using metals is legal. Therefore, we have our delivery method. Secondly we would need a spaceship made of wood. This is possible, since wooden underwater vehicles have been crafted. Using sealants naturally created from sap and other plant resources, coating a wooden spaceship to withstand the pressure constraints would be easy, since this has already been done as far back as da Vinci. Heat would be easily reflected or dispersed through the same sealant, as being a semi-liquid would give it a slightly reflective coating. Implementation: To not break the rules, the weapon would be delivered to space. Once the spaceship is in orbit, the wooden weapon ship would be placed into an airlock and ejected softly, oriented towards earth. The metal ship would then be completely separate from the weapon. Inside the wooden weapon ship, a simple hand operated mechanism made entirely of wood would be the operation point for launching the weapon. A single human following the rules of dress inside this wooden weapon would have roughly 10 minutes of breathable air, or more if a larger weapon ship was created. The weapon itself would be simple. Think of a revolver, in which each round is located in a separate chamber. The same applies to this. When the human pulls his lever, he physically presses these solid blocks of treated redwood towards earth. Since communication methods have been allowed on other examples, such as ships, the weapon operator may use some form of communication, such as a radio, while the pilots of the metal ship tell him when to release his payload. Gravity is the accelerant of these wooden spikes. Once released, they will begin to slowly accelerate towards earth. A lot of mathematics will be required to ensure they hit their targets, and this weapon will be extremely inefficient compared to today's standards, however, this is [possibly the most damaging weapon](http://profusci.blogspot.com/2013/07/project-thor-kinetic-bombardment.html) possible in your ruleset. I say this because a heavy enough rod accelerating towards the ground at an orbital speed can produce as much physical damage as a small nuclear bomb. Imagine looking up into the sky to see 360ft by 25ft redwood tree trunks flying towards your city at supersonic speeds. Boom. [Answer] **Wooden Airplanes** - Take a look at [the Spruce Goose](http://evergreenmuseum.org/the-museum/aircraft-exhibits/the-spruce-goose/), which is actually primarily birch. > > Built entirely of wood due to wartime restrictions on metals, this massive airplane stands as a symbol of American industry during World War II. > > > Also, [the wikipedia page](https://en.wikipedia.org/wiki/Hughes_H-4_Hercules). > > It was designed to carry 150,000 pounds, 750 fully equipped troops or two 30-ton M4 Sherman tanks. > > > --- The entire frame is built using wood, but there are many things that would still have to be modified before *all* the wood is gone: * Fabric is used, for rudders and elevators * 8 Engines, each one 3000 horsepower * Probably other miscellaneous pieces, including glass for windshields --- The biggest issue would be the engines. The least technical solution is using people to generate the power, but people are too heavy and too weak to provide the necessary horsepower. (*My calculations said only 1200 people could fit weight-wise, while 240,000 people would be needed to provide the same horsepower as the engines indefinitely*) My next thought is to burn wood for some kind of "steam-powered" solution. Which *may* work - but I'm not sure the engine itself couldn't keep from burning as well: > > The engines could be sited anywhere that water and coal or **wood fuel** could be obtained. By 1883, engines that could provide 10,000 hp had become feasible. > > > --- Ultimately, I think we would figure out a way to have wooden planes, or at least blimps (*Does the air in the balloon count?*), which could then drop our burning pitch, or wooden projectiles, or whatever - from a high height. [Answer] Am I the only one here thinking about [bioengineering trees](https://www.empa.ch/web/s302/open-positions) so that their wood becomes more weapon-ready? I'm talking about super venomous resins, super elastic / super sturdy materials, exploding wood, or whatever you can think of. [Answer] Assuming that EVERYONE followed this rule, then they would be a thousand times better off. The entire defence budget could be spent elsewhere, and instead of having arms races, we would have space races. Mass murder would be virtually impossible. (Although, presumably murder is also banned in the religion?) I hope I don't need to point out that if there was even just one person who broke the rules, the entire planet would be screwed. There have already been many optimistic people throughout history to suggest essentially the policy that you're theorising about. In fact, the success of Adolph Hittler was partly attributed to the fact that there was a disarmament campaign gaining support in western Europe after WW1. [Answer] I think the ingenious of people relegated to these days would come up with some creative ideas far beyond what we can speculate here...though I'm assuming the majority of military conflicts would look more like Roman days. Properly made, a spear is a stupidly effective weapon and with proper wood working techniques and a suitable tree ('Ironwood' if you will, just really hard wood) the spear is most likely your most common hand held weapon, though blunt clubs and staffs would also see their use. If you look back at weapons, certain ones go out of style in part due to armor. With no armor around, these weapons will still remain relatively effective. Vs an unarmoured target, I would suspect that a person with a 'tree built' sling and a bunch of wooden 'bullets' could inflict a lot of pain upon an enemy. But the real creativity would be in the 'anti-personal siege' weaponry. Catapults are a little more obvious, but there is nothing stopping something from a wooden version of this appearing: [](https://i.stack.imgur.com/zZgV4.jpg) Of course this would be wooden wheels attached to long axles with a rope (made from tree bark of course) wrapped around the axle many many times over. A horse is attached to the one end of the rope and made to run...this sends the wheel rotating at an extreme speed (a person or team of people could do the same if horses are struck down too). Wooden spears/javelins or wooden balls are loaded between the two rapidly spinning wheels and are launched at a silly speed. I would also expect technologies such as the Onager and eventually a Mangonel (<https://en.wikipedia.org/wiki/Mangonel>) would also come to bear. A Mangonel is best described as an 'anti-personel trebuchet' that sprays bullets (in our history these are stone, in this alt-world they would be wooden bullets)...though I will admit these people would have to show some amazing wooden working ability to have that work. I would (wood) suggest that they would reach these skill levels if it was their only choice. [Answer] So what about catapults? <https://en.wikipedia.org/wiki/Catapult> The rope could be made of hanging vines ...which is more or less wood... or use peeled twigs. And you could still use loggs as ammunition. [Answer] Assuming society did advance to the semi modern age... make completely automated drones. Assuming god doesn't strike down the coder whilst he makes the thing ( i think he's safe because at one point decorative weapons were clarified as being safe til wielded to produce harm). Interestingly, this means nukes are a valid weapon. You just have to find 1 guy willing to get zapped to press the launch button. With that in mind, i think most of warfare would be a matter of finding a suicidal, berserker-style fighter willing to use a cannon, or a bomb, or disease, etc. [Answer] Some of these have been brought up, but I'm going to try to condense some things down. Your actual combat is going to be mostly melee with some ranged stuff in there. This is out of necessity of the War God's rules. So, expect most combat to be out in the open. Bows, Atl-Atls, spears and javelins will dominate for ranged weaponry usable by one person. Maybe slings, if you can find a very dense wood to use for shot. Blowguns would be a good stealth weapon, but I don't see it in common use for combat. Melee weapons would be clubs, boken, staves, and daggers. pretty much anything like traditional melee weapons can be carved out of wood. Artillery is going to be regular types of siege weapons. The difference is that they will be slightly less effective due to the whole "only wood allowed" condition. It's going to be used more against people, because wood isn't going to work as well against fortifications like castles. An interesting application of a catapult might be to throw possibly poisoned caltrops at the enemy. pointy things going into the feet is going to slow down all but the terminally enthusiastic. A note about castles. You can't have moving defenses like shields, and mechanisms like doors are questionable, but there is an old time method to defend the entry into a castle that shouldn't break the rules. A long Tunnel with murder holes in it. Imagine a 60 foot long tunnel that has a bunch of small holes all around. Defenders thrust javelins (individual weapons) through the holes at the attackers. Attackers will have no defense. Your goal is to choke off the tunnel with the corpses of the enemy. Some thoughts on the wood. HEdge wood (bois d'arc, osage orange) is dense and may make good sling ammo in addition to bows. Oak, hard rock maple, ironwood would be good for any sort of impact weapon that is swung. By no means a comprehensive list, but just something to get you started. Your world may be a little stunted in the area of metallurgy. Nothing adds urgency to metal technologies as weapons work, but your world is limited to wood for that. Your soldiers may not get the benefit of a GPS unit in their hands, but battlefield directions can still be given within the limitations given. Semaphore, Drums, Trumpets and so on can be used to signal troop movements in battle., but radio, satellites, and so on can be used for intelligence gathering, to plan where the most advantageous place to have a battle. Weapons are only one part of the battle. Wars are won by logistics. if you can get your guys out there, patch them up after the battle, and feed them on the way, you are going to win if you do it better than the other guy. That leaves you open for all kinds of innovations. Aircraft, troop transports, radio...you can even engineer precision wood weaponry with CNC lathes and laser cutters. Keep that in mind. Sounds like a fun world. [Answer] The most powerful weapon - *because it's not a weapon* - could become things like iron filings. Or better still: tiny fragments of wood, processed only so far as is needed to make it be considered "no longer wood". These would then be fired as microscopic, undetectable pellets at the wood of trees destined to be used for weaponry, either during the growth, harvesting, or shaping. These weapons would then become deadly to use. Sabotage of weapons would be a whole new level of arms race. Protecting trees from trespassers, drones, etc would be a fulltime job for armed guards. --- At another level would come the efforts to redefine what constitutes weapon use. If you can define "eating rice" as deadly weapon use, you can perform genocide at a mammoth scale. But first you have to get God to believe that eating rice must necessarily and directly cause a death. So, you need to find a way to guarantee that someone will be killed by every N grains of rice eaten (which is easy enough, since every industrial process ends up causing deaths: you just need to enumerate them), and ensure that everyone *knows* that this happens, so that anyone eating rice cannot but do so by deliberately deciding to contribute towards that death. Rice has become a weapon. It is not made of tree. If there's a ZAP, then good. If not, then there's a chink in the armor: anything which kills people as indirectly as rice is perfectly OK to use as a weapon. Keep experimenting with more and more direct connections between action and death (driving -> car is weapon). --- And then there'd be any number of indirect methods of killing. Causing people to kill themselves or kill others will become the ideal path to cause mass deaths. For example, if dynamite is not a weapon, but it becomes so as soon as you touch it with the intent of using it as a weapon, then fooling people into touching dynamite should be fine. One person can manufacture the bomb, believing it to be for mining. Another can deliver it. Another can change the labelling on it. Another can press the button on it. If intent is the only thing that matters, hypnotize your troops so that they can touch guns and kill, believing they are using fake guns and a computer game. Or give them AR goggles so that they genuinely can't tell the difference between real combat and training. Robots don't have intent, and aren't weapons, but they can be instructed to operate weaponry. --- Finally, there's the morality of the God. If a gang of people are assaulting one person, beating her to death or worse, is it OK to help defend that one person with whatever you find to hand? A rock, a bottle? If not, then God's morality is broken. At that point, the main thrust of humanity's research should be focused around one question: how do we kill God? [Answer] Grow your stave branches around lumps of lead, then harvest them later for a more effective quarterstaff. Technically all you are hitting them with is the wood. [Answer] We here in WB established that [war cannot have rules](https://worldbuilding.stackexchange.com/questions/10241/how-could-war-be-replaced-by-sports/10245#10245) - losing side of any war would ignore the rules and use any fair or unfair advantage to win. ]

[Question] [ Is there a plausible makeup for a lifeform which is highly resistant to even very advanced firearms (or any ranged weaponry for that matter), but can be injured more readily (albeit still a major feat) by close-ranged machinery/arms? This could be a result of the materials the lifeforms consists of, the internal organisation, or whatever you can think of. Another possibility would be to solve this from the perspective of weapon technology, i.e. melee weapons can do something which ranged ones cannot. Further information: I am still not finished with my new alien race :) For added bonus they wouldn't use oxygen. [Answer] Natural materials can be unbelievably tough--spider silk, of course, [mantis shrimp claws](http://www.livescience.com/20811-hard-hitting-crustacean-claw-engineering.html), and other things as well, I'm sure. Take a crustacean, scale it up (non-oxygen-breathing helps here to keep your clever clogs readers/players from complaining about spiracles), cover it in super-mantis-claw stuff. The creature's skin becomes fantastically tough and effectively impossible to penetrate with small arms. Make it an excellent conductor of heat if durability against energy weapons is desired. That covers protection. To address vulnerability, perhaps structure the skin in overlapping bands. An attacker who was very lucky or skilled could slip a blade between bands, reaching the creature's insides. Then it probably dies very quickly, having evolved to rely on its skin to prevent all injury. For example, it may have no clotting ability. [Answer] The thing is, bullets don't actually do that much damage. They punch a small hole through things. That's bad for humans (and most other animals) because: 1. We start leaking bodily fluids (primarily blood). 2. We have vital organs that even a small hole renders useless. So if your hypothetical life form either did not have the same sort of circulatory system (either no blood at all or self sealing and re-routing blood vessels) and no vital organs then you could pump them full of bullets and they would just keep coming. Ever tried to shoot down a tree? You can put a few holes in it but you need a stupendous number of bullets to cut one down. On the other hand hacking weapons such as chainsaws, axes, and even swords at a pinch, will take off large sections of the creature, incapacitating it much more quickly than even a hail of bullets. Of course this doesn't stop the use of explosives such as RPGs, so something else would be needed to prevent that. That could be as simple as an environment that makes such weapons incredibly dangerous for both sides such as a flammable atmosphere or being set in a space station. [Answer] [Shear-thickening](http://en.wikipedia.org/wiki/Non-Newtonian_fluid#Shear_thickening_fluid) blood or sub-dermal layer. > > The viscosity of a shear thickening fluid, or dilatant fluid, appears to increase when the shear rate increases. Corn starch dissolved in water [...] is a common example: when stirred slowly it looks milky, when stirred vigorously it feels like a very viscous liquid. > > > [Here](https://www.youtube.com/watch?v=f2XQ97XHjVw)'s a video of a pool of corn starch with people running across it. In your case, a very fast projectile would bounce off, the layer behaving as a very springy surface. A quick hit of a blade would also bounce off, like hitting a very hard rubber, leaving only a shallow notch. But pushing the blade against the body and applying constant pressure would sink it and get it to organs deeper in the body. Probably the race would be limited by their own shields, requiring slow (lumbering) movement, since fast movement would cause "springy" resistance. The origin of this might be a natural adaptation of a slow race as defense against fast-moving small predators/insects, or natural projectile-shooting ones (say, plants or animals that shoot needles as their defense). [Answer] A very porous being might work. I picture the flesh configured like the picture below, only with holes that are bigger than a typical bullet.  In most cases, bullets would nudge the "flesh" out of the way and pass through the holes between the flesh. Any damage done would be a tiny fraction of the damage done to a solid, non-porous terrestrial animal. The damage would be even less if the creature had a slippery coating like a slug or wet fish. Other weapons that are larger than the holes, such as a sword, club, or larger projectile, wouldn't be able to pass through the holes, and would inflict damage. [Answer] If you want a specific example of a monster that would be invulnerable (or very resistant to) bullet-damage, rather than a list of traits that would make it invulnerable, might I suggest the humble [Blob Monster](http://tvtropes.org/pmwiki/pmwiki.php/Main/BlobMonster) (warning: TV Tropes link). They have a number of anti-bullet attributes going for them: * They have no internal fluids to leak (essentially a collection of 'cells') * They have no internal organs to damage * They're soft and viscous, so certain blob monsters would just 'absorb' the blow. * They don't necessarily feel pain As for your melee attacks, you might run into the same problem with fists and bludgeoning weapons if they're outright resistant to impact damage or ungraspable, but if not, a strong enough fighter could tear it apart more easily than bullets. Additionally, slashing weapons or other more brutal melee weapons would do more physical damage to the slime being. It doesn't have to be completely amorphous either - any being with enough of a 'viscous' quality could have these immunities, and would still be quite difficult to harm in melee (though, as you said, not impossible). It seems like an ideal candidate for what you're looking for. [Answer] How about an advanced alien race which has grown beyond a need for melee weapons? They have created repulsor shields which disperses laser-fire and can slow bullets to a standstill (and, if the being behind the shield is moving swiftly towards the gunman, flings them back a bit), which become less useful the closer they are to the gunman. So small arms might stand a chance at punching through, but a stab from a bayonet or sword would penetrate clean through? I suppose the shield would begin affecting the projectile from a long range, slowing it down over a (comparatively) long period of time. But when a bayonet thrust begins from three feet away, the field cannot arrest the stab in time for the damaging potential to be removed. It would have some effect, like stabbing through syrup, but even then a stab would be significantly better than anything like a rifle. The reason they need to have developed beyond a need for melee is because otherwise they would plan for it. A race designs its armour by standards of the tools it has to crack it, for the most part. So when a desperate human charges them with what, to these technologically advanced beings, seems to be an eating utensil, they would be terrified. More so as said knife guts their commander- without the need for physical plate, their warriors and vehicles might be too lightly defended against melee to stand up to it. Of course, as time goes on, they'd learn. Whether this means an emphasis on more armour themselves, simply arming everyone with flamethrowers, or a more esoteric solution, that's for you to decide. Their non-dependence on oxygen could play into the makeup of the shields. Maybe they use the local air/gases as fuel and output breathable gases into the inside of the shields- a grave surprise to the humans who tried to reverse engineer a shield and were left sucking down carbon monoxide for the rest of their brief existence. [Answer] I would recommend re-framing the problem to better map to the physics of weapons. The line between melee and ranged is an artificial one fraught with difficult definitions. How about the case of a Chinese [Chain Whip](http://en.wikipedia.org/wiki/Chain_whip) which strikes like a ranged weapon but is on a chain to be retrieved. Or the [nunchuck](http://en.wikipedia.org/wiki/Nunchaku) which is one step more melee, having a single chain link between the sections instead of many. Or what about simply blowing sand in the enemy's eyes. Is that ranged? If you're writing a fantasy story, magic can often handle this fuzzy line well. However, if you are looking for a harder form of fiction, magic may not be available to you. My recommendation would be shifting from ontology to epistemology: change from worrying about "what kind of weapon is it" to "how does the weapon behave." It is much easier to define a clear way to stop behaviors of weapons than to stop weapons by name. Can you imagine a lifeforms which is resistant to Halberds but not Axes? It's hard. However, imagining a lifeforms which is resistant to stabbing but weak to crushing is not so hard to imagine (in many games, skeletons are weak to crushing, but virtually impervious to stabbing). In fact, consider: in the last moments before impact, a bullet actually acts like a melee weapon, striking the body directly with enough force to tear tissue. Clearly we will need to define some behaviors What are characteristics of ranged weapons that we might use: * Distance from "wielder" to target. * Usually relies on faster smaller projectiles * Usually strikes a point, rather than a line (sword) or area (club). However, this behavior is identical to how a knife strikes a point (almost exactly identical), so we have to be careful with that. * Beam weapons exist in many science fiction worlds. If they do, they either need to be handled separately, or in concert with any energy based melee weapons (lightsabers!) Many have mentioned the Dune force shields. They work along this behavioral process. Fast moving objects larger than a few molecules cause the shield to raise up and repel everything until the fast moving object goes away. It relies on two behaviors I listed: distance to target and speed. If an object is close enough to be within the shield, it does nothing. If an object is moving slow enough to fool the shield (such as a well wielded knife), it does nothing. Herbert made this system of combat feel "alive" by intentionally sticking to behaviors the shield could do and then relying on the human element to fill in the combat styles needed to work with such a tool. Another common lifeforms which is resilient to gunfire is the zombie. They tend to be resilient to gunfire because they have no small vulnerable areas like hearts or arteries to hit. However, their resiliency is limited: start tearing at them (such as removing the head) and very soon we find their limit. And this is an important point: all immunities should have a limit. If they don't, they start to act funny fast. A zombie is STILL affected by a 20mm machine gun in many mythos' because the raw amount of trauma that round can put out is extraordinary. Even though they are "ranged," they strike with such ferocity that they act more like bludgeoning weapons to the zombies. One approach to making the creatures more resilient to gunfire would be redundancy. Most living creatures are remarkably thrifty: most parts of our body are fed by one artery, and most muscles are innervated by one nerve. A creature which was more mesh-like in its structure would be much harder to kill with gunfire because it could rapidly adapt to those wounds. However, if you have a blade you can slice large swaths of mesh, dramatically increasing the chance of doing permanent damage. With a hammer you can ignore the weak points entirely and just bash on the musculature until it stops working. [Answer] **Ghosts**. Well, not *literal* ghosts, but this might become a nickname for the creatures. What I'm talking about are **creatures that are incorporeal but are, for lack of a better term, "allergic" to solid objects**. Weapons of all kinds pass right through a ghost, but they "stain" parts of the ghost's body as they pass through it, injuring it roughly in proportion to the amount of space that has been stained. **Ranged weapons generally travel in straight lines, with a very low profile along axes that aren't parallel to the shot**. They have to; aerodynamics makes this the only practical way for weapons like this to get much range. But this also means that they cannot stain very much space: a ghost would not be completely immune to gunfire, but it would take a great deal of firepower to hurt it significantly. **Most melee attacks, by contrast, swing through a wide arc, with a profile perpendicular to the direction of movement (or very nearly so)**. This lets them stain much more space than a bullet could, and so they hurt ghosts much more effectively. **There are a few melee attacks that would have to be adapted to this kind of fighting, or else become outright impractical**. There's not much you can do about the rapier, though most other swords would be fine. Punches can be adapted to haymakers and chops, and side-kicks can be swapped out for roundhouse styles. A pickaxe becomes a club with a funny piece of metal at the end, and spears similarly become staves. It's hard to grapple a ghost, though you could try to dive through it. [Answer] The problem with fighting these beastees is that they are fast! I don't mean fast as in run across a field in the blink of an eye fast; I mean they can dodge bullets! It is like they see reality in slow motion and just get out of the way. Fortunately for us, they're heavy and their arms aren't very strong. They don't carry armor or weapons and they don't jump around the field like kangaroos. They just have these little blades that extend from their claws like daggers. When they close with you in combat, those blades scrape across your armor like sand in a sand storm. You've got maybe 10 seconds before the steelcloth starts to shred. Then your done! It's like the death of a thousand small cuts, they just whittle away at you while you scream and bleed. -- edited to cover issues from the comments -- Our greatest weapon in the battle against them are the combat-stimulants in your medpack. Ignore the normal dosage instructions. Use all of them at once. That will get you up to a fraction of their speed. They will still be faster than you, but at least you will have a chance. The rest of your survival probability will come from the sword-craft training we've been focusing on for the last several months, especially the two-handed, figure-eight defense. If you don't have that perfected, you are doomed. -- end of edit -- Here's how to kill em! Drop your gun and get your swords out while their approaching. Don't let em get in close. Keep your swords slashing as fast as you can in an overlapping figure-eight in front of you. Don't even try to hit them with the swords, you won't be able to, believe me, I tried and it took weeks to regrow the flesh on this arm after that mistake. So no, don't try to hit them, just push them back with a never stopping shield of spinning steal... If you can back them into a corner, someplace where they are blocked in on both sides, then you've got em. Wait till their tail hits the wall and watch for panic in their eyes as they realize they are trapped. Then charge in and sink both blades in as deep as they will go. If you're very lucky, you'll still have enough armor covering your chest to keep them from gutting you as they die. Good Luck Men! Go Get Em! [Answer] Another option would be a creature with a bullet-proof exterior, but chinks at the joints which require the ability to reach around. Think of a robot: it's bullet-proof, but if you reach through a chink you can pull out some important wires. Bullets won't hit the wires, however, because you have to bend your fingers/wrist to reach them. [Answer] It may be worth noting that “bullet-proof vests” do not offer very much protection against knife stabs, simply because knives aren't fast enough for that. Now, they don't really help very much against rifle shots, either, but you could extend the technology to the point where they do stop rifle shots, shrapnel, etc. [Answer] An enemy "soft" enough to let bullets/projectiles through sounds like it would do the trick. If you have some sort of "hive entity" like the nano-bots in Big Hero 6, shooting isn't going to do a whole lot. Cleaving through a limb would sever it's connection to the rest of the hive, though. So guns and lasers are mostly useless. Bomb shrapnel would pass through them, though the force of the explosion might disperse them a bit. Swords and other bladed slashing weapons are the only real offense against such a creature. [Answer] Simple enough: a creature with the intelligence and reaction time to dodge projectiles, but is strongly far-sighted. Such a creature would be able to see a distant attacker and react in time to dodge their ranged attacks, but would be unable to see a close attacker and therefore wouldn't know when to dodge a melee attack. If you don't like literal far-sightedness, then you could call it a "blind spot", for example. [Answer] Some creature resembling (and extending the idea of) cephalopods like squids, or similar soft animals like a jellyfish or even a sponge. If they don't have complicated internal organs, a bullet will just pass through them, not doing much damage. However a melee weapon would be able to cut off its limbs and make the creature incapable of continuing combat. Even if the limbs would regenerate over time, a squid-like monster with all its limbs cut off would be helpless, and could be killed before the limbs regenerate (which realistically would take days or even weeks). Similarly, an exploding bullet will pass through a soft enough tissue without triggering the sensors to make it explode. This reminds me of a scene with [Captain Nemo](http://en.wikipedia.org/wiki/Twenty_Thousand_Leagues_Under_the_Sea): The captain and his crew had to fight giant squids, and their guns were completely useless. They used air guns with shocking bullets. The kinetic energy of the bullets themselves would make them completely harmless even against a human target, but upon contact with the target, a strong electrical discharge would kill it. However, these bullets just passed through the squids and didn't trigger the electrical discharge. So they had to take up axes and chop at the limbs of the squids. [Answer] How about some sort of creature that has one size dimension very small. Imagine a piece of paper. It can be super tall and have great depth, but if the width is near zero, hitting it with a bullet would be nearly impossible. If you cut out yet another size dimension like depth, even shrapnel would barely ever hit it. However, swinging a sword/axe horizontally at it would hit it just as easily as any other creature. [Answer] I have 2 suggestions. The first is to use Frank Herbert's shield mechanism from *Dune* as a starting point. The shields had to be surpassed by something slowly in order to penetrate to their target- disallowing most projectile weapons but allowing melee attacks provided the players we trained in how to fight against such a defense. I think the speed was on the order of 6 inches per second. To make the mechanism biological, perhaps the creatures have a thin natural armor that acts as a non-neutonian fluid (As others have suggested). Once that thin layer is passed with the tip of a melee weapon, it can be shoved in at full speed, but this allows for a good defense against ballistic weapons which don't slow down. Another option is to have creatures that bend space-time, in an effect which differs the closer you get to the creature. Perhaps the closer you get to the creature (and the more you're enveloped by it's space time effect) the more the creature slows down to your speed (the relative speed differences diminish to 0). So if you fire a bullet at the creature, it starts out moving slowly (easy to dodge) then speeds up as the relativity bending becomes less extreme. Get within that envelope of being "near speed" (IE in close combat), and the effect is negligible. This is just a rough outline- you'll have to think about how these things affect the ability of pc's to actually approach the creatures, etc. Interesting premise. Good luck! [Answer] I'm thinking of a fairly amorphous organism, such as a slime mold <http://en.wikipedia.org/wiki/Slime_mold> Obviously you'd have to do some work on the concept, but a creature made of a large number of "nodes" held together by some sort of strands (possible with moderate regenerative capabilities) would be able to absorb a large number of bullets. This is for the reason that if you shoot a hole in something fibrous, like a shirt, it still holds together well but if you cut it with something it falls apart. Extra cool points for making it something that is able to assume many shapes. [Answer] Lets take another look at the blob/hive/nanobot ideas above. I don't see how they are that much more vulnerable to swords than to bullets. However, swords aren't the only melee weapons. Lets consider a creature whose individual components are small and very, very tough--bullets shove the bits aside but they're light enough they'll be pushed away rather than destroyed by any velocity you can reasonably bring to bear. (While you can build devices to throw projectiles at speeds exceeding the burn velocity of the propellant nobody's ever made a portable weapon that does this. The closest we have come is the still-being-engineered ship-mounted rail guns.) The pieces are not invulnerable, though. Imagine a weapon that's basically a scoop and a component that fits into it and squeezes the material out through pores smaller than the components of the creature. The pieces are trapped between two pieces and squashed--they can't use their small size to simply slip away from the threat. (And in case it's of any use I'll mention the *Lensman* stories--a few infantry battles take place inside inertialess spaceships. No weapon that relies upon impact works in such an environment, the only way to kill your opponent is to crush them or at least a part of them somehow.) [Answer] Why not just make the ranged weapons not work? If the alien's home turf is surf, then bullets would have a very limited range (see mythbusters for more info, but its pretty much limited to about 1 meter). If your antagonists have a kill zone of greater than 1 meter, then your guns would pretty much be classed as a melee weapon. [Answer] **Anthills** In a [question I asked a few days ago](https://worldbuilding.stackexchange.com/questions/45184/is-the-idea-of-a-collective-consciousness-realistic), an ideals of a collective group of small, ant-like creatures forming a larger species. If a creature like this existed, then shooting it would only kill a few of its millions of ants (so, like shooting an anthill, it is ineffective), but smashing it with, let's say, a baseball bat would cause a large amount of damage. Keep in mind I only use the word 'anthill' as a comparison. The anthill is the collective and ants are the cells (but without all that natty bleeding) [Answer] Anything is possible. In general, melee weapons would actually allow more targeting than ranged one. If your shooting from 50 meters away at a moving target, you probably can't hit that *one* spot except by luck. On the other hand, if you're using a sword, you might be able to. Make your species have weaknesses in specific places that are either hard to see or heard to hit from a distance (for example in the armpit). You could also create a fictional material only available to be created into swords. Maybe it can't stand high wind speeds, or reacts with a nitrogen when it moves quickly. [Answer] ## Curved blades can turn corners, bullets can't Bullets and shrapnel travel in a straight line, a curved blade can turn corners. ## A massive exoskeleton with interlocking plates. A heavily armoured enemy, perhaps a foot of reinforced steel armour with narrow cracks between the joints. A creature with an exoskeleton, like a woodlouse or a beetle. The plates interlock and you need a shaped or flexible blade to slip between then. ## Make a hole, then chuck in a grenade Such a wound seems like it would not be fatal. The attacker could insert a shaped sword into a crack then twist the blade using a broadened T piece, opening up a larger crack into which a grenade could be dropped. ## Dangers to the attacker The main dangers would be losing one's grip on the sword, in which case the attacker would fall and be trampled. The creature would presumably attempt to violently dislodge the attacker. The sword might also shatter, again causing the attacker to fall. [Answer] The big danger from bullets over melee is electrical disruption. A bullet hits the brain or spinal column or even heart and the instant death is from electrical disruption which spreads a wave of dying tissue. We do suffer from major damage to the heart and major arteries which quickly leads to death from blood loss and loss of circulation.. If we were all like a guy I heard about who immune to significant currents and with quick seal to small punctures- hyper-clotting ability which exists in some people- then bullets would be nowhere near as dangerous as a sword. A sword can cause so much gross damage that the hyper-clotting would be joining the edges of the wound- not saving your life. Shotguns would still as hazardous a sword but leather-like skin would stop a great deal of that damage. A jet of water or instant ooze of water pool reduces hypersonic bullets to dust. The creature could be mostly water to fend off fast projectiles and the connective tissues being vulnerable to melee weapons. [Answer] The creature could have an extremely tough but kind of crumbly hide. A bullet is either absorbed like it was shot at a sandbag, or only managages to chip away a small piece of the armour. However, a serated melee weapon could be used to dislodge a large amount of it with a sort of patient sawing action [Answer] ## Kevlar skin Kevlar and other materials that are used in bullet-resistant armor work by distributing impact force over a wide area, lowering the damage a bullet can inflict. But these materials often have fairly low shear strength, a knife can cut them easily. There's no reason why an organic creature couldn't have a similar material for skin (spider silk is even stronger), but it would need to have a plausible reason for evolving it in the first place. Perhaps one of its potential predators uses a fast, hard whip-like attack that inflicts a strong impact in a small space, but has low total energy, similar to a bullet. Worth noting that bows or crossbows might be able to hurt this creature where bullets will not. ]

[Question] [ Human-vampire hybrid wakes up from hibernation that started in the late 30's and finds that world has changed. What kind of knowledge from the 30's would be best starting point to learn computers & networking? [Answer] The best starting point would be knowing about [Turing Machines](https://en.wikipedia.org/wiki/Turing_machine). Alan Turing thought these up in 1936, so your human-vampire hybrid could have learned about these shortly before entering hybernation. In case you are not aware, a Turing machine is basically an abstract version of a computer. It's a theoretical device that can compute anything that can be computed. Computers are really just fast Turing machines with fancy outputs. If your hybrid had heard about Turing machines, waking up from hibernation and seeing computers would, instead of being a "what in the world is that" experience, be a "wow, they actually made them" experience. [Answer] [Math.](https://stackoverflow.com/a/171543/356438) It's the basis for computer languages and would give a good starting place to learning modern languages. The first low level programming languages where created in the 40's, and high level languages in the 50's. So the vampire would not have had any experience or knowledge of computers in the 30's. Knowledge of math would at least give a background in abstract logical thinking and make things easier. [Answer] My great-grandfather headed an Electrical Engineering department from 1946-1956, just as the important transitions into electronic processing were being made and WWII computing technology became unclassified. During his tenure as chair, he purchased the university's first computer, [REAC 100](http://www.cowardstereoview.com/analog/rico.htm), and hired some professors to develop on it. His background was in electrical engineering and acoustics. He wrote papers on such things as [electronic hearing aids](http://jamanetwork.com/journals/jamaotolaryngology/article-abstract/558523), [communication theory](https://www.amazon.co.uk/course-electrical-communication-Edward-Hartig/dp/B0008B1OS8), and [bridge circuits](http://ieeexplore.ieee.org/document/6431457/?reload=true) during the 1930s. This would probably be the best applied background to make the transition into computational sciences. [Answer] # Anything that involves processing data Computers are all about... well... computing. So first option would be some kind of profession that deal with collecting, collating and computing data. Preferably so in an very strict and organized manner according to certain procedures / algorithms. * Mathematician * Librarian * Cryptanalyst / code breaker * [Census taker / registrar](https://en.wikipedia.org/wiki/Tabulating_machine) * [Weaver](https://en.wikipedia.org/wiki/Jacquard_loom) * Geographer * Navigator * Author of [mathematical tables](https://en.wikipedia.org/wiki/Mathematical_table) * Computer (yes, that was a profession) [Answer] The 1930s had the battle grounds where the formal mathematical definitions of computation were hashed out, there's a [random internet find timeline here](http://fm.csl.sri.com/SSFT15/Timeline.pages.pdf) with all the popular names, but I think that's pretty irrelevant. Most computer users today don't go for a mathematical understanding, even advanced users. But the hundred years or so leading up to that had enormously relevant inventions. Your wealthy and curious Vampire could have known about the existence and some-level of workings of these computer precursors: * Prisms, lenses (historical), Fourier transform (1822) + Sound and light are things you can measure and calculate on * Charles Babbage's Difference Engine (1823+) + calculating by machine instead of human; a serious design and attempt at cog-and-gears calculation, funded and supported by a national government) * Electric telegraphs and Morse Code (1836) + long distance communication + encoding letters as signals + electrifying a message and delectrifying it somewhere else + electric machines with output devices - buzzer, beeper, direction indicator dial * Punched-card telegraphs (1844) + information storage on machine-use paper, not human-readable * Teleprinters (1846 ish) + keyboard on one end of a wire, electric link, printer on the other end + all-in-one electrify/encode/decode/delectrify * Boolean algebra (1854) (AND, OR, logic) + foundations for chaining electric switches together * Mechanical typewriters (1868) + print, on a small scale, without a printing press or any typesetters! + a way you could make a dot matrix printer * Baudot code (1874) + Morse code was meant for human use, Baudot code was not meant to be human readable, but machine to machine. * Wax cylinders and phonographs, photographs (late 1800s) + Machine storage of audio and visual information. Only text or drawings until now. + mass produced cylinders and prints. Mass storage. * Electric radio with vacuum tubes and codes (1896) + signalling without wires. Also: lighthouses, signalling with light. * Electric light (late 1800s to early 1900s) ([blinkenlights](https://en.wikipedia.org/wiki/Blinkenlights)) * Sinking of the Titanic, famously with radio call for help (1912) * World War 1 (19whenever to yeah yeah everyone's forgotten this by now) From there, they are close to knowing about encoding letters as code symbols, representing symbols as electric signals, reconstructing electric patterns into useful output, about recorded and stored information (paper, punched cards, pressed audio cylinders), about decomposing sound into frequency blocks. The jump to encoding sound measurements as code symbols, storing words on pressed cylinders, representing text characters with lots of very small lightbulbs (pixels), using those lightbulbs as dots to represent pictures like in a newspaper print, keyboards as electric typewriters, and tiny control circuitry is a matter of disbelief of scale or practicality rather than disbelief full stop. Cherry picking these examples really makes digital computers seem inevitable, doesn't it? I'll say the best thing your Vampire could know from the 1930s era was enough of these things: **telegraphs**, keyboard style interface for writing with **tele-typewriters**, the existence of **signalling codes**, and the use of **electricity to power and control things** (switches, lights, machine tools, sewing machines, beepers, indicators, dials, readouts) that it seems reasonable that the combined effects could give rise to modern computers, that computers are surprising only in scale, not in principle. The real mental jump problem is 'stored program computers can do things' and I can't think there's any reasonable way a person from pre-computer era will be able to grasp that intuitively without closely following up-to-the-minute math developments. But signalling codes, electricity as a controller, and feeback systems in general, give as good a background as they're likely to get. And the mention of WWI is that the Vampire would have lived through it, and would have seen both the desperation of the participants, the burst of technological development (foot warfare to tank warfare, no planes to aircraft, more and more submarines, etc). and could maybe have seen economic problems of 1930s Germany and stresses in Europe. Therefore learning about WWII would not be much surprise that the scale was bigger, the weapons were more deadly, the war was longer, and the technology boost was starting from a higher place and pushed harder and faster. [Answer] Library science. It helps people to think in terms of storing and finding information, which is what "the net" is all about. Perhaps a bit of mathematics on top, graph theory. [Answer] Somebody already mentioned Turing, but that has to be number one. The second thing to pick up on is **Claude Shannon**'s work. In 1937, he wrote a thesis demonstrating that electronic circuits could simulate all the constructs of Boolean algebra. Given that mathematicians had already shown that the rest of mathematics could be built up from Boolean algebra, this pretty much lays the basis for electronic (rather than electromechanical) computing. He did a lot of significant work in the 1940s, as did Turing, but that's outside the scope of the question. Another thing to look into would be Polish decrypting techniques of the late 1920s and early 1930s. These techniques led to the construction of the Bombe, a device that was replicated at Bletchley Park in Britain during WWII. It's probably worth learning the differential analyzer, designed by **Vannevar Bush**. This was an analog computer, and therefore could be a distraction from the mainstream of the future, which would be digital. But it would give you a handle on the power of simulations. Knowing that, plus the knowledge that digital simulations would eventually come along, would be helpful. And, of course, there's **Herman Hollerith** who devised a scheme for storing census data on punched cards in 1890. His company was bought out by a sales man for NCR, who gave the company a new name, "International Business Machines". IBM would remain in the punched card business until 1954, when it decided to take over the computer industry, more or less. And, of course, the work of the first programmer, **Ada Lovelace**. Her work had been around for almost a century in 1930, but it was still ahead of its time. She practically invented software engineering as a separate discipline from equipment design, and previewed the development of artificial intelligence. If you want some background on other innovations available in 1930, take a quick peek into *The Innovators* a book by Walter Isaacson. He outlines progress in infotech from Babbage through Google. The first couple of chapters should give you lots of material. A lot of this stuff was old by 1930, but learning it at that time would put you ahead of the curve. [Answer] In addition to math (especially binary), [Morse Code](http://engineering.nyu.edu/gk12/amps-cbri/pdf/TE_Activity_Morse_Code.pdf) would give a good understanding of how computers communicated with each other. --- **Edit:** My apologies. I think Morse Code is a bad example. Perhaps I should have said the telegraph and [Baudot code](https://en.wikipedia.org/wiki/Baudot_code). Baudot would introduce your vampire to the concept of 5 bit character encoding so the concept of 7 or 8 bit ASCII (or just bits in general) wouldn't be a drastic leap for the vampire. [Answer] The sort of mechanical computing people were doing back then was things like this: <https://www.youtube.com/watch?v=s1i-dnAH9Y4> There are useful precursors; Morse code is a binary code he might know. He would not have used a calculator, but might have used a slide rule, which requires him to know how to convert numbers to logarithms and back for multiplication and division. (That’s still a technique electrical engineers sometimes use under the hood to implement those operations in hardware.) The layout of modern keyboards is the same as mechanical typewriters, although most men of his time would not know how to use one, because that was a job for women. Telephones existed, but there is literally nothing about a modern phone he would recognize, not even the concept of reaching people by dialing only digits without talking to an operator, or of leaving a recorded message instead of getting a busy signal, or that it’s possible, much less expected, to call someone up when you or he are not at home and rude to show up unannounced. Movies existed, but not television or VCRs, and you couldn’t watch video in color any time you wanted and pause or go back whenever you felt like it. Science fiction wouldn’t help him much. Isaac Asimov two decades later was still imagining that the engineers in the far future of his space operas would carry in their pockets unimaginably more-advanced slide rules. As for social changes, if anything, science fiction of his day was behind the times. The part of the curriculum that’s changed the least would be pure math, but there are still a lot of huge differences. He wouldn’t have learned to add or subtract the way old people today think of as “traditional,” because that’s the New Math introduced in the 1960s. Proofs were something he learned in geometry class, not something done in high school algebra, a lot of his time would have been spent memorizing techniques to do by hand calculations that are now always done by computer, it wasn’t generally accepted that the foundation of mathematics was ZF set theory, and nobody has even heard of the Rule of Three. He’s essentially a foreigner in the modern world. People don’t walk, talk or dress like he expects. Especially women. Everybody wants to be on a first-name basis. Radio exists, but he wouldn’t recognize anything on it. Newspapers exist, but nobody reads them and even the comic strips are tiny and crude. If anything, computer programming is the one aspect of his daily existence at a university today least likely to cause him culture shock: the Internet and video games would be weird, but he has no expectations about them to violate, and computers are possible to completely understand. [Answer] **Step 1:** Look around for some days to get an idea of current world and society also set a camp/safe-house somewhere. **Step 2:** Keep doing step 1 and start asking people about "security" and "measures" taken while doing some crime and learn how **not** to behave strange by using some hypnotic-power you have. **Step 3:** Get an idea of "how people are educated", specifically in *that field* using your hypnotic-powers. **step 4:** find a university and track **bright** students and *ask* them to help you by giving some tuition at their home/rooms. Now, if your vampire is **this** much smart then he will have a safe-house, rough knowledge of modern society and a bright friend who will be willing to teach him computers and will be far less suspicious. [Answer] Definitely understand that whatever computers (and embedded computers in appliances, cars, industrial control etc., and ANY "digital" electronics) do these days would have always been done by something *mechanical* or *electromechanical* (relays, electromechanical counters...) back then, not by something built with early electronics (or only using these in very select places, eg. a photocell amplifier)- these were expensive and large, and reserved to tasks that required dealing with *mostly analog* (speech, video), *fast* (an electromechanical system will usually be hard pressed dealing with things happening in less than 1/1000th or maybe 1/100000th second, or signals above 1-100kHz ... non-electronic telephones,loudspeakers... are among the faster electromechanical devices) and *weak* (a radio signal from an antenna cannot operate a relay or motor usually, a signal from a microphone will not drive a loudspeaker directly, even though electromechanical amplifiers did (rarely) exist) signals/events. Telephone exchanges (that already existed at that time) are a good example of an electromechanical system that handled "digital" tasks (and they were still built new that way well into the 1970s in some countries). Somebody understanding how these worked could understand a lot of computer logic by seeing it as a very fast acting telephone exchange that used electronic switches instead of electromechanical ones. Electronic controls on eg. a tape recorder or household appliance are a good example of something that only became economic to do electronically in the 1980s - earlier designs used complex mechanics to do these things instead. [Answer] By the 1930s there were devices whose operation was controlled by complex electrical circuits. [Push Button Elevators are a good example](https://books.google.com/books?id=qUFOAAAAYAAJ&dq=elevator%20wiring%20diagram&pg=PA1061#v=onepage&q=elevator%20wiring%20diagram&f=false). [Relay Logic](https://en.wikipedia.org/wiki/Relay_logic) was being used to control sequencing of machinery: > > large relay logic circuits were employed from the 1930s onward > > > See also [George Stibitz](http://history-computer.com/ModernComputer/Relays/Stibitz.html) > > ... studied the correspondence of statements of symbolic logic with binary relay circuits while a graduate student at MIT. Shannon wrote his graduate thesis (published in 1938) on that subject ... Clearly the idea of using relays to implement binary logic was common in the late 1930's. > > > The seeds of digital computing were well planted by that time. [Answer] I suggest "Maths". The proof is that Maths was my whole/only background, before I was introduced to computers. Someone (a mathematician) who's trained to accept algebra (e.g. "x = y + z") can extend that to computer programming: it's symbol-substitution. Perhaps for a similar reason I think that alternatively some of the earlier 'boffins' might have been linguists: bilingual or multilingual, whether with modern languages or classics (Latin or Greek). Training for multiple languages, translating from one language to another, might be another kind of good preparation for a programmer (i.e. it's symbol-substitution again). I guess that (personal) character/disposition is important too. A programmer needs to be willing to read the manual[s], spend time alone with the machine. If you can only get your kicks from interacting with other people, maybe you won't be willing to study this kind of stuff. FWIW I learned the elements of networking at my first employer too. The historical terms you'd want to be familiar with are "circuit switching" versus "packet switching" (and maybe "multiplexing"). I presume that most modern networks are packet switching. --- My career as a programmer started in the early 1980s: before personal computers were common, and before programming was a frequently-used option at university. I'd hardly used a computer by the time I left university. I read a couple of programming language books (Fortran and Cobol) from the public library when I was 12 or so -- and having read them I thought that, "maybe when I grow up I'll work for a company big enough to actually own a computer, to program". Nevertheless (in spite of the fact that most graduates didn't have experience with computers) my first employer (Bell) employed 100s or 1000s of programmers. I think they figured that people who could learn Maths (at university) could learn programming, if they were hired and given a computer terminal. I think I learned, given: * Hardware (e.g. a terminal) and office space * Introduction to a programming language (book) * Programming reference manual * Software tools (text editor and compiler) * Existing source code to read, run, debug, and modify * Software specification (i.e. defining what the software was supposed to do) * A year or so * A manager to give me tasks, and a competent QA process to test my edits. [Answer] Lets see... I think he would not keep up with what the world has now, even in computers (seriously, my dad is 65 years old and he doesn't know how to turn on my computer.). Lets give this as a example. Your computer puts up the welcome screen. You have a 600 year old vampire, with a knowledge of computers equaling that of a child, I'll bet he would say "Thank you" to the computer screen (and how about if you describe to "open a window") The basic knowledge which he must have is the the basics, turning on the computer, what happens when it turns on, what happens when windows pop up, and what to press or not, which in the 30's does have that kind of system, but is not as complex as our current computer system. If you will, give your vampire a calculator first. [Answer] Railroads. He will understand the concepts of bandwidth, power, routing and speed. Having him be an expert vampire railroad baron would be advantageous for your story. ]

[Question] [ A common concern with immortal fictional characters like vampires and the like is the frequency with which they'd have to change their identities and move around in order to avoid people noticing how they don't age. This would require the frequent forging of legal documents, driver's licenses, etc. This would also make banking extremely annoying, as they'd have to keep opening and closing accounts with businesses that are pretty dang strict about their standards for identification. But a solution occurred to me: What if there were certain banks that were secretly run by immortals, and secretly maintained persistent bank accounts that their immortal clients could access regardless of which identity they're currently using? Of course, the way I understand it, major banks have to do a lot of reporting to the government regarding their operations, so obviously running accounts like this is going to involve a lot of extremely illegal activity to obfuscate the true nature of these accounts and who owns them. But I don't know precisely what specific obstacles they'd run into, or what the best methods of concealing the nature of these accounts would be. **If a bank were to secretly keep accounts for immortals accessing the money between multiple fake identities over decades or even centuries, what would be the easiest way to do this while concealing the accounts' true natures from the government?** [Answer] # Maintain a Bank Account for Above-Board Immortals American law already grants personhood to immortal, soulless entities bent on twisting the minds of innocents to their will and consuming everything in an unending, unslaking lust for power. They're called corporations. Noss 4 At You Inc. has a rotating C-suite with signing authority that all seem to do their business by night - but the corporate credit card and bank account are entirely above board and no one is even going to look at them twice. The account has no reason to cease, and (forged) death certificates for the expired identities of its lone board member and employee won't affect the legality of the account. [Answer] South Dakota and Delaware (and probably some other states) allow you to set up perpetual trusts. The money in the trust is either doled out to the named beneficiaries or spent for the their benefit according the rules of the trust. Current beneficiaries can name their successor beneficiaries so you can pass the money down through a chain of identities. A US trust pays a higher tax rate on its earnings than the individual would (40%) and has to file tax reports but assuming the person has an address and tax payer id number that shouldn't be a problem. And the financial company running the trust wasn't curious, about the "family resemblance" between different people, it should work pretty well. It would probably work even better financially if the trust resided outside of the US although the person receiving the money, if a US citizen or resident would have to report it and pay taxes on it. You could read up on off-shore trusts to find out more. [Answer] Banks are only one industry that requires identification - they will need to be able to identify themselves in many areas of life. Therefore, the logical immortal will go a step deeper, and try to find a process by which a birth can be registered through the proper channels, without the inconvenience of an actual child - perhaps by working a brief spell in a registry office every 40 years or so. If they can do that, the bank is one of many potential obstacles that simply ceases to exist. A bank run by immortals will run into the same problems as our immortal friend - at some point, the ownership needs to change, and changing the CEO of a bank is rather newsworthy. You would need a whole society of immortals so that the CEO role does actually change hands, and again, those background checks would be important for such a high profile role. Therefore, our lone traveler might favour using a standard banking service with a business account, which can be conveniently 'inherited by their child' with no fanfare. Ideally, they'd want their company to be bought out by another of their companies every century or so, so as not to provoke investigation into a company that's been trading for many centuries with no apparent purpose. They might also look into a wealth management firm. These are fairly common, and specialise in handling unique circumstances. They would be happy to handle all the financial affairs of an individual who takes their privacy seriously, and would also be happy to take over his estate and handle a smooth transfer of assets to their child. [Answer] People are usually concerned about the age of other people, not about the age of abstract entities. Your immortals do not open a bank account on their name as physical persons, but open one (or more) under the name of an institution or association. That John Doe is 250 years old may rise some eyebrow even among the most inattentive people; that the association "Friends of Haggis & Whiskey" has the same age can look normal. That the association is nothing more than a metal plaque on a door is something that require investigation to be found out, and considering how much effort does it cost for the police to find out and uncover these schema when used by criminal associations, it's very plausible that the same would hold for your immortals. I don't think one can be an immortal without learning how to swim among the big sharks. [Answer] ### [Phoenix](https://en.wikipedia.org/wiki/Phoenix_company) the bank every few years, and trim history when you do. Every decade the bank should declare insolvency or get into debt, and buy its own assets out into a new trading name. This is a common practice, it's technically illegal, but happens quite often. It's a good way to cheat on your tax bill too. This actually happens in finance already, I once had a single credit card with a bank for 4 years, the bank behind it had 3 different legal names in that time. Same board of directors, same card, same account number, same assets, same ads, same website even, different corporate owner. (My suspicion is it moved from one tax haven to another). Every time the bank is purchased by "new" owners, transfer the account information to a new computer system / new database. Each time you do this, the slight difference in database format will be result in data loss: * No need to convert transaction history older than 2 years - that will just slow the conversion. * The old system only allowed M and F for gender, the new one allows 20 choices? Better to just clear the field rather than pick incorrectly. * The new system has different name length restrictions to the old one. Better email all the members and ask them to confirm their name, title, etc in case the old records were incorrectly entered those years ago. + If they were, we should correct the record at import, rather than pollute the new system with the incorrect data - it was wrong all along. + This process should be automated using an online system - for efficiency. Lest some non-immortal teller gets suspicious by a total name change. * The old system stored date of birth as a string as DD/MM/YY, the new system uses the database's native date field, but because of ambiguity for those born in 1905 vs 2005, the system didn't guess. * This should allow customers to subtly transition to a new identity every few decades, but keep their same account number. ### Also - Have a branch in America, but registered offshore. So you can start your own bank overseas on a budget. For under 80,000 Euro, [you can start your own bank in the EU](https://www.ellex.lt/en/news/news/obtaining-a-specialised-bank-license-in-lithuania-has-become-easier/40662). There is cheaper options available, I've heard as little as $5000USD in Central Africa, but can't find info online at short notice, and the perception of trust and regulation is important. Your bank is an overseas bank operating a branch in USA. Think HSBC - "Hong Kong and Shanghai bank corp", but headquartered in London, but you can get an account in the USA. All the records are held overseas, outside the easy access of the US government; From the USA's perspective it's an opaque routing number and account. They can get the data with a warrant, (the bank will comply if law enforcement get **that** interested in someone - that's a condition of their license to operate in the USA), but this helps limit big data outing the immortal by scanning bank records. [Answer] While vampires have some of the same financial needs as immortal corporations, they’re a lot more like organized crime. They want to hide their dealings, and live in constant fear that they will have to flee with as much untraceable wealth as they can carry at any time. At the same time, they need pin money that won’t raise suspicion, and also some highly-liquid assets they can cash out in an emergency. So you might look at some of the money-laundering and shadow-banking networks that criminals, and networks such as ISIS, use. This is especially true if there’s a cabal of rich Masquerading vampires who can make deals on the honor system, since if they can’t trust each other, it’s all over anyway. For example, selling real estate and antiquities at inflated prices is a common form of money-laundering, and bearer bonds are still legal in some places. The suggestion that immortals would be anarcho-capitalists is silly. (For one thing, anarcho-capitalism is not very old and has less of a track record than the US dollar.) They want to earn interest on their investments and pay people in cash. I suppose an individual vampire could believe just about anything, or have grown up to believe that real money is gold and silver. But that’s a poor investment, easy to steal, and hard to move or hide. And, if they’re old enough to remember the Depression, they will also remember that financial panics were just as bad and happened just as often when the country was formally on the gold standard. [Answer] **Human servitor** In most vampire settings, vampires are able to recruit humans to serve them. You could in this regard have a look to the role-playing game mascarade (which I found well thought on this aspect). For bank human can be used as nominee. I can be a risk for a vampire to set up all his worth on one human being. And no smart vampire will ever do that, they may split it as much as they fit. So in your case is even simpler the bank knows, who is who and the nominee don't get much real power on the money on the bank. The main issue I see is when you need to alter human nominee you would have to cover your trace and may have to pay taxes... Surprisingly human nominee have all a testament ready and no close relative. Why a human would serve a Vampire: * Immortality, The vampire promises that if he serves well he will be rewarded by becoming a vampire to. (don't forget a vampire won't have to fulfill his promises, just that the human belief in it long enough). * Vampire blood is often describe as a powerful drug, with high addiction, and anti-aging effect that disappear when you stop having vampire blood regularly. * Mental manipulation, some vampires are described as able to influence "lesser mind". * Power, an immortal being can become really powerful and rich, and the human may not even know why he gets so much money for this job, he may not even want to know and will discards weak sign. * Not knowing it, manipulation is a powerful tool, imagine it in the hands of a century old mighty being. I know this answer have some loophole, But I can't imagine vampires without humans Mignon. [Answer] ### The word for a financial institution dedicated to an immortal entity is "religion". Think about it... You have a collection of followers, nationally or even internationally, all of whom pay regular offerings/tithes in the hope of long-term benefits from their Lord(s). The institution will last as long as it still has followers, without any requirement for the immortal being in question to actually manifest themselves - and indeed the lack of a readily-observable immortal being at the top of the organisation is ***expected***. For bonus points, masquerade as an obscure sect of an existing religion, with strange rules that ensure other members of the nominal religion can see you're different. The "inner secret" of who actually controls the organisation can be a deeper mystery, revealed when you're bitten (and hence controlled by the vampire who bites you and unable to tell anyone else). There is no requirement (in most countries) for any oversight of where the money goes. And as with most organisations, most of the money goes back out into running the organisation, with only a very small amount taken by the people at the very top. Realistically a vampire isn't going to have much living costs, so their expenses only amount to a small overhead. A successful vampire knows all about blending in and staying undercover after all - and the unsuccessful ones don't survive. (Most being killed by their fellow vampires to avoid the secret being revealed, of course.) This sounds extremely evil. It doesn't have to be, though. Churches don't just exist for the hierarchy at the top - they can also serve as a focus for good deeds by their members. And the reason the House of Lords in the UK contains Anglican bishops as members is to (theoretically at least) provide long-term moral guidance which might otherwise be lacking from a secular world. As an agnostic/atheist, I don't really subscribe to that hypothesis (look at what's happened with children's homes run by religious organisations, for example), but then our religions are run by short-lived humans. I certainly wouldn't discount vampires running their organisation on the "benevolent dictator" model, and actually being a force for good. Of course vampires still need their quota of blood. Conveniently though, a religion tends to encourage priests to visit people who are ill or dying. Much vampire literature considers the moral issues with having to kill humans in order to stay alive, with a common theme that any surviving vampire has to be a sociopath otherwise they'd kill themselves instead of killing other people. An ethical vampire could limit their impact on humans by feeding on people who are already on the verge of death though, and "last rites" would be a very effective way to achieve that. [Answer] An immortal would want an immortal bank in an immortal country with a centuries-long track record of immortality. An immortal would want an immortal currency with a centuries-long track record of immortality. An immortal would want a banking system run by politics that they could trust with a centuries-long track record of stability. America and the greenback does not even come close to these requirements. No immortal would ever trust an American bank or the American banking system. It just does not have a good track record. I suggest a better bet for them would be to find some very small, unobtrusive country that they could completely take over, and totally control, and form their own banking system and regulations with that country. You know, like financiers currently do today with Panama or the Cayman Islands or Jamaica or [some very good ideas here.](https://www.msn.com/en-us/money/taxes/11-places-where-the-rich-hide-money-from-the-irs/ss-BBYMnjY).... > > Offshore tax havens used by individuals and corporations cost > governments trillions of dollars annually. According to the estimates > of some economists, individuals have stashed anywhere from about $8.7 > > trillion to $36 trillion in various tax shelters around the world. But > not all of the tax reduction tactics favored by the rich necessarily > involve offshore accounts in the Cayman Islands or Bermuda. There's a > variety of other places the rich hide money in order to lower their > tax burden each year and shelter some of their income, many of which > are quite straightforward. Here are some examples provided by tax, > personal finance and small business experts. > > > But never, never, never in a country that can not be completely controlled by immortals. In fact, if they were truly immortal, then their best bet would be to set up an operation in a truly neutral, non-political, non-nation, non-regulated, non-controlled spot devoid of any governmental institutions without its own currency or monetary policy governance like a completely hidden, completely covered, base in Antarctica, beyond the reach of the regulatory laws or fiscal policies of any one nation. [Answer] Put each customers assets in a separate LLC. The LLC can legally hold assets like a person but its just a legal entity, and as such it would not raise any flags if it continued to exist for hundreds of years. If anyone asks, just say the LLC has been privately held by family X for several generations. To spend the money the client has a company credit card. All expenses are charged to that card, and then the LLC pays them. Any cars, real-estate, etc can be owned by the LLC and used by the client. As for a drivers license, the last cop who pulled one of them over went mysteriously missing. [Answer] Two strategies: What the really rich do, and get real fake identities **(1) What real wealth multi-generational families do?** The short answer is to google "Single Family Office". Wealthy multi-generational families have a organisation dedicated to serving their personal and corporate needs - from PAs, security and travel, to property management, special projects, PR, charitable giving, investments etc. Or whatever they wnat. They already plan with a very-long term perspective, just for real multiple generations. With offices in multiple countries, resouces squirreled away or perpetually "in transit" etc. This bit of the problem has a real-world solution in place. The only challenge remains creating new legal identities every generation. Seems to me that with planning it wouldn't be hard to double-up some birth registrations. Take the mother-to-be to two doctors (perhaps in different countries). After a home birth register the birth twice. After that it is mostly paperwork. Keep the parallel papertrail going. There may be a few occassions when a body must be presented but likley can be managed in the same way. Criss-crossing jurisdictions would make it much easier too. When a suitable age, the identity is adopted by the immortal. Repeat every 40 years or so. **(2) Certain agencies routinely create false "legends" for people** Intelligence agencies, witness protection schemes, etc routinely create robust fake identifies for people using REAL government documents, accounts etc. So one needs a good relationship with some of these people Would have to think through whether certain select people would KNOW about you and be aware of what you were doing, or whether the Chinese Walls in such organisations would mean they wouldn't realise there was a sequence of identifies with ever-later birth dates. If you are actually invulnerable-immortal you could make oneself VERY useful to these people (the film "The Old Guard" is a lovely exposition of this). If you are merely unaging-immortal there are probably still ways of building such a relationship (wealth, knowledge and patience!). **The biometrics problem** An emerging problem would be the ever-increasing use of biometrics to establish identify leading to double-matches. So far things like passport biometrics are primarily confirmatory - you present an ID with pre-established biometrics and it is confirmed that you are a match. With some - police fingerprint databases say, as opposed to a simple fingerprint lock - the systme is used prospectively to identify the person without a reference identity to confirm. I am not sure how certain these matches are, vs what size database. But over-time the chance of them popping up in a list of possible matches with two or more of your identieson them would seem to increase. Of course we don't know how immortality works - finger prints wear out a bit over time. Perhaps immortal fingers will change enough over decades for this to be a problem. Perhaps their DNA is mutable as a consequence/cause of their immortality so it won't match so well (but are their genetic markers for immortality that someone could notice). etc [Answer] The oldest banks are about 500 years only, and they survived by miracles . Most banks, in recent history, fail badly and need bailing out by the taxpayer every decade or two. They are very, very poor places to store money, identity, or anything. Despite the marketing and grandiose buildings. Immortals would be best off simply periodically liquidating assets into cash/gold and moving residence while keeping their wealth in gold, diamonds, art , sculptures, and the like, physically moving their wealth with them. Believe me. I speak from experience. [Answer] **Endowments** Large university endowments are [some of] the [best performers](https://www.insidehighered.com/news/2020/01/30/endowment-returns-10-year-average-rises-leaders-see-clouds-horizon) among invested private capital. Your secret vampires have been around for a while, and surely amassed a large fortune, so they "endowed" a/some university/ies, and in exchange get a "job" at the university or even managing investment of said money. ]

[Question] [ In my story I would have a completely independent and elusive group of assassins. They would not be sanctioned by either a king, wealthy merchant, nobleman or by the church. Because of that, if it turns out that the group actually exists, members would be hunted down in an attempt to shut down the organization because it would be a threat to those in power. Assume that this is a medieval world without magic and that the group has managed to remain completely hidden. What is missing in my story so far: How does the group accept assignments without getting noticed or found out? I have a few options, but I'm not sure if they're feasible and what other options there are: * The group uses traveling story tellers: medieval style tv/radio commercials. * Inn-keepers or socialites who know the protocol required to contact the group. Either way these intermediates would otherwise have a normal occupation, would be compensated for their efforts and have no direct contact with the group so they couldn't betray an individual. **Edit 1:** Thanks for pointing out the incorrect use of 'guild'. Now I'll have to come up with an alternative way for the group to legitimize themselves. :-) **Edit 2:** What I like about some of the answers is that giving an assignment to the group poses a risk to the client as well. I'll see how I can integrate that into the story. [Answer] "Don't call us, we'll call you." Your assassins are actually primarily spies. They spend most of their time digging into the secrets of the rich and powerful: those mostly likely to have both the motive and the means to spend large amounts of money to have someone killed. This would be through intermediaries a lot of the time; with networks of informants who don't know that the buyers of their information are the assassins guild (I'm assuming plenty of regular intrigue here, with numbers of nobles and merchants wanting to keep tabs on each other anyway, so a few more bribes and break-ins could go unnoticed against that backdrop). The assassin's guild does not advertise any means for would-be-clients to contact them. Instead an agent of the guild approaches (in secret) a potential client when they already have reason to believe the client would be willing to pay for their services (possibly as simple as hearing about the potential client's attempts to figure out how to contact assassins). The continual espionage also provides them with plenty of blackmail material, which can both help keep them hidden and provide a layer of insurance against a misjudged client (the other layer being obvious). Of course there will always be rumours of the assassin's activity; no sizable group operating for an extended period of time could remain completely undetected, especially when people are disappearing often enough for the guild to be making an income. [Answer] I would probably go with a religious order. Leave a sufficient offering at the temple of `<insert vengeful deity here>` and your enemy simply disappears into the night. The people don't really need to know how it happens, just that it happens. The silent, chaste, and otherwise unassuming monks either are or are the contact point of the assassin's guild. In the event of a monotheistic world they could be the order of St. Swithen's, the patron saint of lost causes. Who's been known to help a person out from time to time... If you know what I mean... Being a religious order carries a certain respectablity that would help an assassin's guild maintain a "beyond reproach" place in the community. --- What I'm trying to say is... On a long enough timeline, no matter how many intermediaries you have, those people will be tortured into giving up the goods, you need a mechanism to prevent it from coming to that point. [Answer] I like a lot of the answers here, particularly the ones regarding having people that are already in *"Secretive Professions"* do the client management portion. However, there's one thing that The Elder Scrolls V : Skyrim did well, and that's the **Dark Brotherhood**. At the point the player meets the guild, they operate by showing up to a location by request. This request is signaled by doing an elaborate ritual involving bones, blood and other items. Since none of the guild members posessed a way to know when others performed that ritual, what they'd do was that they would simply pay very close attention to rumours of people trying to perform the ritual. They'd also notice people carrying the exact items needed for said ritual. By doing that they ensured that people thought they were (still) calling upon a magical entity, while doing all of the labour without any special power. [Answer] **They stay hidden by not existing (anymore)** As you noted, rulers would never let this kind of group exist. The first thing any newly-minted despot would do is start trying to root out this organization so they can never be used against him. After all, what good is a government if it does not have a monopoly on violence? Maybe such an Assassins Guild could exist for a generation or two (with great effort and luck), but ultimately they won't be able to maintain that for long, and some emperor will eventually find them and (functionally) wipe them out - he has his own armies, spies, and assassins after all, why contract when you've already got employees for this kind of thing? But, the populace *love* boogeymen. They need to blame their problems on some anthropomorphic evil entity or organization. When someone influential is murdered in the unique style of the Assassins Guild, Joe Farmer can rant about how those heathen killers are ruining the country. Similarly, Joe Farmer knows well enough not to poke into their affairs, because he and his family could be next. **So let's suppose** such a group *used* to exist, and an emperor wiped them out after a generation or two. But he realizes it is in his interest to *pretend* that they're still around. So he teaches *his* spies and killers how to copy the style of the Assassins Guild. Whenever he has a rival threatening his rule, he can just have them killed *in the style* of the Assassins. Whenever he discovers a servant of his was disloyal, he can have them killed in the *style* of the Assassins - perhaps without revealing the disloyalty, so that it appears like the Assassins are still accepting contracts that hurt him. He can even set up "sting" operations so that when someone tries to contract a killing the emperor doesn't approve of through the Assassins, that person is instead "taken care of" (maybe killed, maybe the emperor's spy network can "leak" damning information and ruin the guy's life). Even better, the powerful merchants of the nation can still use the Assassin's services - which cost large sums of money. Unbeknownst to the merchants, they're actually paying the emperor directly. The emperor can even boost his population's morale from time to time claiming to have found a safe-house of the Assassins, burned it down, and captured/killed one of its members - perhaps the member responsible for an unpopular assassination! [Answer] And now for something completely different... Use harlots, concubines, prostitutes. The lowest class in many societies, but they (as an organization at least) have enough dirt on enough people to keep things under wraps. They're the guild, or the contact point. Anyone who acknowledges contacting them would be an immediate pariah. So polite people don't, or at least they don't talk about it. --- What I'm trying to say is... On a long enough timeline, no matter how many intermediaries you have, those people will be tortured into giving up the goods, you need a mechanism to prevent it from coming to that point. [Answer] The skilled undercover agents watch while the rank amateur bumbles around trying to make contact, then makes clandestine contact himself. This is portrayed humorously in the movie [*Mystery Men*](https://en.wikipedia.org/wiki/Mystery_Men) (deleted scenes/director’s cut) where the characters think that the way to contact *The Sphynx* is to order a specific combination of dishes at a certain Mexican restaurant. They make a spectacle of themselves ordering various combinations in an effort to guess the code. Meanwhile, a worker at the restaurant, later revealed to be the civilian identity of The Sphynx, is watching their antics with great mirth. [Answer] > > They would not be sanctioned by either a king, wealthy merchant, nobleman or by the church. > > > Which leaves organised crime and outlaw groups, pretty much the same way it is thought to happen today. Your assassins shouldn't be contactable at all by Joe Bloggs or Prime Minister X or General Y. It should all be done by intermediaries who then subcontract the actual dirty deed to the guild. [Answer] Spread the method through stories and legends. Say you have your traveling bards go through and tell stories of the powerful and shadowy assassins. Part of the story is the method to hire an assassin, and the price for different hits. > > "And so the merchant went to the graveyard at midnight and left a note on the grave of the assassin with the name of a wealthy merchant on it. The next day, under the guise of visiting the grave of a relative, he walked past the grave of the assassin, and saw written in chalk the number 1000..." > > > The next part of the story would tell where to drop the payment. Some stories would tell of the penalties for not following the instructions to the letter (mostly painful death) or double crossing (painful death for your entire bloodline, forward and back). The assassins would have the locations staked out by members, and informants in every level of government to let them know if anyone is trying to be clever and locate them. [Answer] Maybe use superstition. There's a long history of superstition, luck-offerings, and other attempted bargains with the supernatural. None of these were sanctioned by the wealthy and powerful (especially not if there's a church who would not like *competing* with these superstitions), but they persisted even in the face of concerted opposition. Most such offerings are small - a bowl of milk for the fae, salt over the shoulder to ward off bad luck, ribbons tied to a tree, sweet herbs offered to a fire, coins in wishing wells. The point is, though, the offerings would already be in the culture, a jumping-off point for the assassins to spread a...certain story. After all, given the idea of small offerings for luck, why *not* big offerings for assisted luck - especially if or when words gets around that this offering, this story, seems to *work*. So, now to make it work. Someone might, if they were looking for a little extra luck, give an offering to a wishing-well (or cursing-pond, who wants to dive into a well) and speak their wish aloud. The "water spirit" won't take a direct hand unless the coins one is offering are gold, though. Or One heard that there's a little old shrine in the woods, there. If a person had an obstacle in their path, one would go to the flat topped stone, bury an offering of coins there and lay a token closely representing their target on the flat stone, and the obstacle will meet an *unfortunate end*. Or There's a wishing tree down that trail, old and gnarled, and folk will tie offerings on the branches with their written request, and coins, tucked inside the pouch. If one offers a generous handful of silver, the tree sprites may offer the very worst luck to one's foes. Or, well, any small tale like that. The assassins would keep a watch - maybe even use it as a training exercise, or punishment, since it might be boring - and so they would see who is offering, and who they want removed, and can immediately grab the offering and make sure it's enough. Additionally, if there's some confusion about what was requested for some reason, there's the fact they will likely know the local gossip, and therefore can figure out who they are being asked to target, or else the use of a written request (rich enough to hire an assassin can mans can leave a name in a note) or a token absolutely identifying the target. And if all else fails, or if the payment isn't enough, or anything else, they can slip a person in to negotiate with the one asking personally. After all, they *know* this person is interested already, don't they? The story will need to be carefully written, when first started, so they don't get too many requests for, um, services not offered. Maybe make it known it's a cursing-place instead of a wishing-one or the spirits involved are dark and deadly, to keep the requests to death and mayhem instead of healing or other miracles. Also, they should have an idea of what to do if someone does offer a payment for something they can't or won't do, in mistaking the process for a genuine spirit offering - maybe returning it, unseen, to the one asking would be both an impressive proof that someone was listening, and underlining that not all bargains will be accepted. But after a while, it will become a set routine. People will know what they're asking for, and what they're getting, and what the price is. Customers found by other methods can be told this is how to get in touch for repeat business. There will be plenty of people attesting that this offering really works. Maybe people will realize it's just a contact point, a dead drop, or maybe they will genuinely believe it's a spirit-thing - but either way this guild has got a contact point that does not lead back to them (since they can watch any potential customers and approach at their leisure). [Answer] I've avoided that specific concern by presuming that people of influence (i.e. those who could afford to hire an assassin) would have a pre-existing relationship with the guild. A member of the palace has his assassins on retainer, because if there is a guild then there is likely to be a constant need for them. This in turn offers a picture of an unpoliced, vigilante-driven environment. You could also consider a different angle - if the guild needed business, how would they reach out to potential clients? Usually through existing mutual contacts, mandarins and professional service-providers (lawyers, etc). [Answer] Homing pigeons and a public-key encryption algorithm. Such an algorithm would not require computers, it could be accomplished with math and a pencil and paper. Each assassin would personally train their pigeons. The birds would hang around the village of interest to the assassin. The hiring party would first encrypt their instructions using a key contained in the pigeons message pouch. This would be the public key and would have been generated by the assassin. The hiring party would put the encrypted message in the pigeons case along with their own public key. They would assign themselves a meaningless set of characters in place of their name and include this name in the message. The pigeon would be trained to fly in a misdirecting path before traveling on to the assassin. Any attempt to follow the bird would be futile as they would fly way too high and fast to keep up with. Trying to get a general fix on location by watching the direction the pigeon started off in would also be futile as the bird would never start off in the ultimate direction it needed to travel to find the assassin. Upon receiving the orders, the assassin would decrypt with their private key, then reply with a simple yes/no, and a fake name to identify themselves, a banks name, a bank password and a price. A complex price would be ideal, not a round number, just as an extra layer of precaution. This return message would be encrypted with the hiring party's public key. They would then send the bird back to the village. The bird would return to the village and look for the hiring party. Birds have excellent facial recognition so they would excel at this. The bird would contact the hiring party discreetly, and the hiring party would decrypt the message with their private key. Any attempt to intercept the bird would be pointless as the message would have been encrypted and can only be encrypted by the holder of the private key, which would either be the hiring party or the assassin, depending on which direction the message was going. Upon receiving the terms of the deed, if the hiring party agrees, they would deposit money in a new account under the fake name. As a courtesy they could send back an encrypted yes/no and date to the assassin so the assassin doesn't waste a trip to the bank and doesn't go too early. The assassin would check the agreed-upon bank for a deposit of the exact amount under the fake name and retrieve the money using the password they provided the hiring party. In this scenario, the only one who knows anything interesting is the pigeon. Good luck getting that pigeon to talk. Pigeons don't rat. [Answer] > > How does the guild accept assignments without getting noticed or found out? > > > An idea that I don't think was presented yet would be that the guild is proactive rather than reactive. For example, they work as spies out in the kingdom and hear that Bobby Jim wants Timmy Rim to die. After careful study from afar to determine sincerity, monetary resources, willingness to betray to the watch, etc- Bobby is approached at night when he's alone by guild members who tell him he can pay right then and there for the job he wishes. The approach could be on his own turf or perhaps they can just kidnap him and interrogate him elsewhere. Obviously the guild will be 'noticed' by whoever contracts them but I don't see a way to avoid that. If you want someone dead and they suddenly die- you're going to notice it happened- especially if you somehow pay the price for it. However, the only way they'll be 'found out' would be if something like a sting operation occurs, hence the studying period. [Answer] Your idea is right and need one more step ## Chain of intermediators Inn-keepers are so fickle. When the guard use an *indisputable argument* like `Spanish boot` then they stay so gabby. But nobody could tell what it don't know. So inn-keepers know someone, story tellers know another and they are different people which know *awared*. And only these *awared* know it's not a single assassin but guildy. ## Different social layers Inn-keeper talks with travelers, merchants and servants. They are useful... but don't have a lot of money. More famous, powerful target then more famous, hard and therefore expansive assassination will be. Of course, a prince could talk with his doctor, he with own wife, she through 3 people with *knowing* story-teller. But more often, nobel man have 2-hope link with the right person. For example, his bodyguard knows *inn-keeper* or *"inn-keeper"* himself. Prosperous guildy should also have insiders between barbers, comediants, lawyers and many others [Answer] Establish a literal [Assassination Market](https://en.wikipedia.org/wiki/Assassination_market). Have betting happen on the exact place and mode of death of someone. Whoever assumes/is in control of these factors can profit from a risky bet without being provably involved. [Answer] **The Dark Brotherhood is a great example present in fiction** Historically, the Dark Brotherhood required the Black Sacrament; a gorey ritual and prayer. The Night Mother hears the prayer, and reports it to the Listenter, who dispatches the assassins to tend to the contract. However in Skyrim the Night Mother was lost, and the organization relied on spies to track down suspected performers of the ritual. They must have had a relatively extensive network, as people of all walks of life were capable of being heard. The in-universe explanation I can fathom for their continued success of tracking down users involves * An iconinc ritual, which grants your organization an air of mystery * A unique and extensive shopping list for this ritual * Bribed merchants who watch their townspeople for purchase of some of these unique items. Merchants could be compensated via commission for the kill. Incorporate these elements for your league of assassins, and you will have murderers summoned in such a way as to strike fear into any government. [Answer] How about they don't sell their services on the open market, but only work in conspiracy with other criminal or dark organizations, whom they "trust" (or at least trust to not be the authorities). Occasionally a powerful or rich client might be able to contact them through underworld contacts, but primarily they service other criminal gangs. As you can imagine, if a bumbling drunkard - who wants to knock off his wife who just left him - can contact them, then any reasonably competent authority can as well. ]

[Question] [ In most stories regarding movies, games or books, the art of necromancy is often seen as a "dark" and/or "evil" type of magic. I've not really come across any characters using this type of magic for the greater good, instead villains/antagonists are often associated. A few examples are: * [Sauron](http://lotr.wikia.com/wiki/Sauron) (The Lord of the Rings books and movies) * [The Lich King](http://wowwiki.wikia.com/wiki/The_Lich_King) (Warcraft franchise) * [Night King](http://gameofthrones.wikia.com/wiki/Night_King) (Game of Thrones series) I'm currently trying to create a world for my video game where the protagonist/good guy is trying to master the arts of necromancy. For example, he will be raising skeletons from the grave to fight other evil beasts that oppose him. Since this concept is kind of "unique", I'm trying to understand the reasoning why this type of magic isn't ordinary to be mastered by the good guy, or maybe even get some tips how I could make this work. **Protagonist abilities** * Raise multiple corpses to fight for him (without permission from the dead). * Communication with the recently departed. * Manipulate souls. * Reanimation. **World rules** * Takes place in a medieval era. * Religions are present. * The protagonist is a necromancer that needs to save the world. So my ultimate question is: **How do I make society not consider this as an type of "evil" magic and will leave him alone or even help him to save the world?** [Answer] There are two reasons why necromancy is commonly thought to be evil. Raising an army of any sort to terrorize the countryside is considered a pretty evil act. To raise the undead is to desecrate their corpse and grave. This could also include transgressions against any religious institutions involved in the burial process. Pillaging the countryside, desecration, and acts against religious institutions are considered evil in most societies. The former can be avoided by not having your necromancers commit evil acts especially any acts involving the use of undead minions. The later requires a culture where the animating of the recently deceased isn't considered a transgression against them. Some ideas for this include: * Let donating your body towards charitable labor be an acceptable funerary choice. * The honored ancestors of the living are animated, decorated and cared for by their descendants and used to construct monuments/temples to the wisdom of their generation. * If the animated corpses are intelligent and communicative people could employ necromancers to awaken ancestors for important events like births, deaths, marriages, divorces, baptisms, excommunications, etc... [Answer] There are a number of reasons why it's considered evil. Some are pretty culturally specific, but some apply more generally: ## It's gross Dead people are unsettling. They look like people, but wrong. It gets even worse when they do things dead people aren't supposed to do, like make noises or move — something that is known to happen with real corpses. Besides the uncanny valley effect, corpses are also known to stink and spread disease. When people see your zombie soldiers, they'll be horrified. In fiction, using tools that are considered gross signifies an evil character. Even relatively harmless symbols like spiders, snakes or blood are rarely associated with good characters. ## It violates bodily autonomy Most people still have some possessiveness over their body even after they die. People draw the line in different places — many are ok with being used for organ donation or scientific experiments, but few would accept being taxidermied and used as an art piece. I imagine being used as a zombie soldier would be even more controversial. It gets worse when the corpse in question is not your corpse, but the corpse of a loved one. Seeing that beloved dead person's body walking around and being used for tasks would be traumatic to say the least. ## It interferes with the order of things This is related to the first point. Dead people are not supposed to work in the world of the living. They may have various things to do in the afterlife, or they may just be gone. But using them for tasks is not the proper order of things and offends many people's religious sensibilities. ## How to get around these restrictions One way I could see to get around this is to make the zombies not very corpse-like at all. Maybe they're skeleton soldiers, but the important thing is that you can't tell which individual they were when they were alive, and that they don't stink, don't rot and don't spread disease. It should also be relatively clear that they're just material beings and the soul of the person in question is off doing whatever souls do in your setting. The other option is to have zombie soldiering be an opt-in prospect for victims. Maybe there's some kind of spell a person can cast as they die, to free their bodies for use as a meat robot. A good guy would only use corpses of people that have explicitly allowed it. A different option would be to have the undead actually be sentient. They're still walking corpses, but the corpse's previous owner is willingly cooperating the entire time. Maybe the soul is even able to leave the body whenever it wants. [Answer] A world where necromancy has no evil connotation, where bringing the dead back to life is openly embraced? ## You're living in it. [](https://i.stack.imgur.com/A2HCG.jpg) **Figure**: *The reanimation of dead tissue, 1791*. By the end of the 18th century, electrical pioneers had begun to refine their knowledge of the often-fatal electric shocks that were a hazard of their research. Galvani in Italy had discovered how to make an animal's extremities twitch and jerk by the application of electricity, which doesn't sound all that surprising until you realize that the animals in question were *already long dead*. There could only be one conclusion: the body, long thought by philosophy to be under supernatural control, was merely an electrical machine like any other. Philosophy gave way to science as researchers like Vigouroux in France and Tarkhnishvili in Russia (modern-day Georgia) probed the electrical activity of the human body. By the twentieth century, humanity was ready for the next step. Kouwenhoven, a New York-born electrical engineer educated in Germany, began studying the electrophysiology of the heart. [](https://i.stack.imgur.com/7oyvn.jpg) Initially his work was motivated narrowly: the linemen running the first electrical wires to customers were dying from a previously unheard-of heart condition, and nobody knew why. Their employers, nervous about their profits, financed Professor Kouwenhoven's experiments. Over the course of the next several decades, Kouwenhoven and his team dug into the electrical workings of the heart, finally surfacing a great secret of restarting a stopped heart by applying a countershock. By the early 21st century, thousands of people each year have been brought back from the dead using Kouwenhoven's inventions and procedures. The practice of electrically inducing a heartbeat where once there was stillness is today embraced by all the ancient religions with hardly a second thought. And yet... who among us can claim to know what it is we're really bringing back? [Answer] Well, according to OP, in his world the hero will fight "evil beasts". I'll use that in answer with an *example* that you can utilize by getting the parts that fit into your world and story. Let's suppose humans can't directly fight these beasts - maybe they expel poisonous gas, so any "living" being would die if near them, even from the distance needed for firing an arrow. Or they can smell humans from a long distance, so only a non-human could approach them. Your world doesn't have gunpowder, and stone throwers are not exactly "portable". However you have magic - but the distance needed for firing a fire ball is still too near to kill these beasts without being killed, or maybe they're immune to "magic damage" (in this case, you'll have a good excuse for why a creature would survive a ball of fire just because it's magic - but that is outside the scope of this question). Also you don't have different planes of existence to summon creatures from there, and mental manipulation magic doesn't work on these beasts due to their alien minds. They don't have the technology and resources to build constructs, since most of their resources are expended fighting the beasts. These beasts eventually attack the frontier towns, capturing people to eat due to their love for human flesh. They eat humans by absorbing their fluids and all soft parts, leaving only the hard bones, without knowing who was that person. They leave the remains of the dead in the middle of forest/fields/whatever that exists between the beasts lair and the human civilization, so after the beasts retreat to their caves the survivors can recover the bones to bury them, without knowing who is who - which avoids the negatives of "seeing my beloved ones as skeletons". However, they don't reproduce so fast, and they don't need to eat so frequently (and/or have access to other sources of food, as animals, that are easier to hunt but not too tasty), so humans are not being extinct - or maybe they are, but the development of necromancy skills (see below) is fast enough. This situation continued for centuries, so society evolved to live in these conditions - including culture and religion. Then a new religion (or other kind of social movement, maybe just a new branch of existent religions) emerged - a religion where hatred for these beasts was a dogma. They said: "The most desired thing for a spirit of someone killing these beasts was revenge - revenge by their own hands if possible". This civilization starts to change their view of necromancy - not only because their attitude changed, but because only the dead can approach the beasts to kill them without being "killed" - since they are already dead. So, they start to develop necromancer units to raise the victims of the monsters to destroy them as armies of skeletons! And your hero is one of these necromancers. Communication with the dead is viewed as a good thing, since by that the spirits of dead can say how much they hate the evil beasts who killed them, boosting the morale of your troops. So, this is an example of how you can make acceptable to use necromancy skills - **have a hated enemy that for some reason can't be confronted by the living**. [Answer] Mostly because necromancy in its core defies the cycle of life. Humans believe that everything have its beginning and its end. By being a lich or raising the dead you show that there is no end. And your death release you from your living duties. In the same manner the stories of ghost who can't rest until they finish their earthly tasks. But with ghost they act on your own while necromancers and liches still have power over a corpse. It's like when you wake up and say "5 more minutes". And someone will not let you rest those 5 minutes. **Edit to answer edited question:** Remember that what is good or evil is made by society.So your examples of Sauron and Lich King are considered evil by their enemies. For their "people" they are good. What is good? They cap the amount of casualties by recycling warriors, don't push economy into spiral by moving goods to war effort (dead soldiers already have their armour and they don't need to eat). Also punishing dead enemy warriors by forcing them to fight on your side is a major psychological bust for your people "Don't let our boys die for our country" and down for enemies "We have to fight our brothers!" [Answer] Necromancy as magic is not always viewed as evil. Odysseus performs necromantic ritual during his travels. Ovid mentions it in his works as well. It's more of the dead divination (asking dead for guidance/answers/prophecies), than making undead creatures. The Bible forbids even these practises and Mosaic Law prescribs the death penalty to practitioners of necromancy. Still, we have King Saul had the Witch of Endor invoke the Spirit of Samuel. The witch was quite shocked she succeeded and the whole thing ended badly for Saul. And later Christians rejected the idea that humans could bring back the spirits of the dead and stated those were in fact disguised demons, connecting necromancy with demon summoning. During the Middle Ages necromancy became "demon magic", something evil and this kind of stuck. [Answer] Many people have brought up the reasons why it's considered evil to **us** in particular: death is sacred, uncanny valley, and typically necromancers are using the dead in... violent ways. Here's one no one else has brought up; **the souls**. very often, necromancy involves binding the souls of the dead to their corpse in a way that isn't... pleasant for the soul involved. After all, if it was simple animation of bones and flesh, it'd be a golem, not a zombie. In many fantasy worlds, the existence of the soul is something that must be taken as fact, and those souls must be treated humanely, that is, allowed to move on. **A zombie is more than shambling flesh; it is a torturous prison for what used to be a sentient being.** It can build all the orphanages you want, you're still using labour derived from unwilling souls. [Answer] ## Because the writer says it is, in real life it varied * In some cultures, and [even](http://www.huffingtonpost.com/janelle-pietrzak/bone-washing-a-day-of-the_b_8403284.html) [today](http://www.dailymail.co.uk/news/article-3780998/Indonesian-villagers-dig-dead-relatives-dress-Ma-nene-festival.html), dead relatives are dug up and taken to festivals because the corpse was believe to contain the soul. * In ancient Egypt, living relatives regularly brought [offerings](http://www.reshafim.org.il/ad/egypt/funerary_practices/funerary_objects.htm) to graves in order to nourish the soul of the deceased. * In European history, [necromancy](https://en.wikipedia.org/wiki/Necromancy) was limited to speaking with the dead and Christianity claimed that mediums were actually speaking to demons. * The dead generally came back to life under their own power as ghosts or revenants. Sometimes, they came back as man-eating monsters particularly if the now soulless corpse was possessed by a demon. * The concept of [zombie](https://en.wikipedia.org/wiki/Zombie#Folk_beliefs) slaves comes from the history of Afro-Caribbean religions and slavery. In the religion of vodun, a fate worse than dead is being enslaved after death. This is the horror of the zombie. * In ancient China, [urban myths](https://en.wikipedia.org/wiki/Jiangshi#Origin_stories) circulated that sorcerers sold their services to reanimate corpses in order to transport them to receive funerary rites, in contrast to Haitian zombies. ## If the soul isn't suffering, it's not wrong If the soul is not suffering, then there is no moral reason that animation is wrong except for respecting property rights. The corpse, by most laws of inheritance, defaults to the ownership of surviving relatives who are free to do with the corpse as they wish. If they want to donate the body as a laborer in order to pay off bills rather than deal with the additional costs of a funereal, that is their right. For an example of how arbitrary the morality is, look no further than the *Necroscope* series. The protagonist is a medium or "necroscope" who speaks with the dead and may call upon them to rise from their graves and assist him. The antagonist includes "necromancers" who mutilate corpses to learn their knowledge, which the dead souls feel despite being dead. Otherwise the dead don't care about the condition of their unfeeling remains. [Answer] Depends some on how serious your death barrier is. Some worlds treat death like it's no big deal. You're dead, but you can come back when X happens or after enough time has passed. In such worlds, a necromancer becomes a cog in the machine and little more. The problem with this type of world is that death becomes a [rather cheap mechanism](https://en.wikipedia.org/wiki/Comic_book_death) > > In the comic book fan community, the apparent death and subsequent return of a long-running character is often called a comic book death. While death is a serious subject, a comic book death is generally not taken seriously in the real world and is rarely permanent or meaningful other than for story or thematic purposes. > > > More often, though, death is as serious as it is in the real world. In the real world, the dead don't return. In other words, death becomes a rule. This brings up some flaws they tend to suffer from # Flaw #1: The high cost of raising the dead I can think of dozens of stories where the price to break the rule is incredibly high. A common theme is returning a dead person costs the life of someone else ([the Naruto universe is one example](http://naruto.wikia.com/wiki/Summoning:_Impure_World_Reincarnation)). # Flaw #2: The ends justify the means We tend to view people who break rules very dimly anyways. The problem, as with any story, is that once you break a rule, breaking any other rule becomes steadily easier. Probably the best modern example of this would be [Lord Voldemort](https://en.wikipedia.org/wiki/Lord_Voldemort) of the Harry Potter series. He discovers a way to cheat death, but doing so means killing someone to obtain this power. As you learn throughout the series, it involved killing not just people for the power to cheat death, but killing people who didn't like that he was killing people. # Flaw #3: The product is deeply flawed Necromancy seldom produces something as good as the original. It's like a caricature of the person. Zombies are mindless corpses. Most other stories will typically give you something that is just less than the original. In other words, Necromancy generally cannot satisfy the desires of the person who wants the dead returned. [Answer] > > **Contract** > > > Hereby, I, undersigned ......................, further referred to as "tenant", agree to renounce ownership of my body, further referred to as "commodity", to ......................., further referred to as "owner". > > > In exchange for the commodity, owner shall provide next of kin with compensation, or services outlined in annex to this contract. > > > As of the signing of this document, tenant is the sole inhabitant of the commodity. Commodity may be collected at owners discretion upon date or conditions agreed upon in annex. Measures of collection include but not limited to repossession and eviction. > > > As per statutory laws, this contract is considered binding for eternity. > > > Signed ............... > > > **It really is very tricky and problematic. You would think that voluntary contracts would remove moral problems, but they don't, for multiple reasons:** * Zombies don't eat, offering monthly wage compensation for control of zombie to next of kin could easily lead to people killing themselves to support their family. If economy or political situation is bad enough. With time, that would easily become standard practice. * In feudal society ("society"), it gets even worse as serfs are pretty much lords (king or noble granted the land by king) property. Zombies don't revolt, don't eat, don't question and don't tire. Zombies are much better serfs than people. "Since they are my property, I can do whatever I want. I'll hire a Necromancer to zombify them all" will think every nobleman ever. * In more modern society it's not any better. A lot of seemingly voluntary things are not voluntary. Situation where your option is to die and sold off or have your family starve or worse, have entire family repossessed for debt or trespassing (because they couldn't afford rent, thus became trespassers) really isn't voluntary. It's a case of normalised and systemic threats. * Notice that mock up contract above is deliberately constructed in a way that explicitly permits murder. It's euphemistically referred to as eviction. Definitions in first paragraph are designed specifically to make it seem less evil. * If you are in pre literate society, forging signing such contract would be excessively easy. In fact, even in fully literate society, there is little means or incentive to verify validity of contract - they are dead anyway, why bother? **Animation of soulless dead, is pretty much completely out.** If it's involuntary it's straight up evil. If it's voluntary then as shown above, it most likely isn't voluntary at all, and opens can of worms which will easily lead to very slippery slope. # But there are necromantic powers which in my opinion could be used for vaguely defined good ## Post mortal Life extension Death is inevitable. Some may very well prefer to stay alive as undead with restricted agency, than pass away. If in your world it is possible to animate corpse and bind original soul to it while granting that soul sole control of the body, then it can work. In this case, Necromancers are pretty much MDs who step in after pathologists are done analysing what caused death. If it's possible to bind soul to another body, then similarly to previous paragraph, we are back to capital "E" Evil whenever it's done. ## Funeral services and more Zombies move around despite the fact that they should decompose and fall apart. I presume Necromancy found a way to slow that down. Guess how long it would take to invite all the guests to funeral of the king in times before efficient mass transportation? Three months isn't unheard of. If only there was some method to prevent or slow down decomposition... Hey, guess what? Maybe Necromancers can disassemble their spells, figure out what slows down decomposition, and build spell around that? If it's better than mundane methods, sure it would be useful in funeral services. Heck, if this spell slows down growth of bacteria and fungi, maybe it can actually be used for food preservation! Food preservation is and has always been important. Basically, I'm advocating for analysis and research into matter, to uncover and re-purpose ["Required Secondary Powers"](http://tvtropes.org/pmwiki/pmwiki.php/Main/RequiredSecondaryPowers). ## Post mortal communication and legal representation One of the common tropes is someone expecting death taking measures to tie off the earthy matters. Unfortunately, not everyone has a chance to do so. Perhaps Necromancers merely contact the dead and represent dead to handle "unfinished business". They could be contracted by family, or deceased himself might take measures to contract such services before passing away. # As you can see, there are non-evil ways in which necromantic powers can be used, however they require out of the box thinking or re-purposing something people don't really think of when they hear "necromancy". Classic raise the dead for battle, will be evil no matter what, best you can achieve here is "lesser evil". [Answer] You need to overcome the following limitations which is on Earth practically applicable everywhere: * Fear of death * Believing that the remains has bounds with the former being * That dead people need rest and do not want to be disturbed The culture in which the Necromancer was born *has no fear of death*. Sure, children are afraid of everything, but if you think logically about it: *Death is inevitable, so what do you have to fear? What is the difference between not knowing your timepoint and knowing your timepoint? You are content with your life, but once you know you die (which can happen any time!) you are devastated? Is that reasonable?* The culture came to the conclusion that it isn't. The rite of passage is in fact a (possibly deadly) test that you do not fear death. Once a marriage is completed, both spouses will in their first night share their most intimate secrets in the knowledge that every day could be the last day. Once a person dies, all the people knowing the person will perform a sacred ritual. In it the person will say ultimately goodbye from the known and beloved person and treasure their recollection. The body will be completely annihilated because only animals are left rotting in the earth. Anything more like collecting remains is a sure sign that the farewell was either uncompleted or that the remaining person is sick and need to be cured. There is absolutely no connection between the body and the soul, it does not bother a person from that culture if bones are animated. Hint: This also means that both ghosts and undead leave the normal citizen unfazed. The task of the necromancer is to allow spirits to fulfill unfinished tasks. If a person had shared everything with his soulmate and dies contently, *he/she cannot be neither raised nor contacted*. If this is not a case, the necromancer and the soul are beginning to bargain the price for salvation. The soul will finish a task for the necromancer, but it will also demand salvation. The worse the condition of the soul is (full of guilt, has debts, never talked to anyone about its problems), the higher the price the necromancer can demand. If a necromancer dies before saving the soul, his/her soul *belongs to the soul* (Do I need to say that this is really, really bad?) Therefore most necromancers immediantely perform the salvation. [Answer] One option is to make re-awakening a *desirable* thing: --- He woke and found himself lying in bed. At first he thought that he had slept late, after a long unpleasant dream that still hovered on the edge of memory. He opened his eyes to an unknown ceiling. *'We are in the House of Healing, Dae son of Aik,'* he heard a familiar voice say. *'We're back home.'* *'Hidr!...'* he shouted, but only a mewling left his lips. *'Shh, rest now. You have been asleep for three days; your body is broken, and it's a miracle that it survived that long. But your feats of courage where witnessed by all, and this morning the Voice of Malik called for you. Today you join the Immortals,'* She said, that lovely smile in her face. They won. He would join his famous grand-grand-grand-grand-grandfather among the sacred warriors of Malik. And, most important of all - she survived. And the kiss they shared afterwards would be the last he would experience while still breathing. --- The ceremony itself was quick: They sat facing each other, the Voice and the Warrior, his heavy breathing betraying the precarious state of his flesh. She spoke to him, and yet her lips were closed: she offered her hand, and yet she was sitting motionless in front of him. He took her hand, and all worries, all the weight on his shoulders seemed to vanish. He saw his own body being taken away, to be prepared for his final residence. He also saw his ancestor standing nearby, his ethereal presence a soft, pale glow. *'Welcome, Dae son of Aik, and thanks for making this old warrior proud as you bring honor to our House once again. Your soul will be reunited with your body soon, but the latter will require no food or rest; the Light of Malik will provide sustenance eternal.'* He felt a gentle breeze, and closed his eyes. When he opened it again, he was back to the House of Healing, no longer a mortal. The world seemed to glimmer with new colors, his undead eyes absorbing both the natural world and the ethereal plane. [Answer] The problem of necromancy being evil is completely cultural, just as death rituals vary throughout the world it is entirely possible for a culture to exist that views necromancy as not only not evil but good in and of itself. To begin with, the religious beliefs of the culture would likely have to view the body as a vessel for something that is the person. So a soul, spirit of life force whatever you want to view it as. This means that once the person has left the vessel than the vessel is useless unless used in some other manner. Once the person left the vessel it would be wasted unless someone came along and used it, now they could use it for fertilization etc but that would leave the bones behind so even then skeletal necromancy would be possible and if the society needs workers wanted. So really in order for this to work you need to build the culture and the religion of the society around the divorcing of the person from the vessel they inhabit. [Answer] **A brief history of Necromancy** First - why is necromancy *evil*? Short answer? It's a cultural thing. Long answer, not all cultures throughout history have considered necromancy evil (and we are talking about Earth Cultures, here). Etymologically, Necromancy comes to us from ancient Greek, and means - pretty much literally - divination by means of a dead body. The earliest Necromancy was probably practiced by shamans and druids, who would call upon the spirits of ancestors and the deceased to have questions answered or seek guidance; this kind of magic was practiced throughout the ancient world, from Babylon to Latinum, the Eastern reaches of Persia and down into Egypt. Divination of this sort only became widely regarded as *evil* during the Middle Ages, when the Catholic Church branded Necromancy to be "demonic magic", espousing that it was actually the summoning of demons taking the guise of spirits in order to deceive the living, and that only the power of God could resurrect the dead. Despite persecution, Necromancy really flowered during the middle ages, spreading with the cultural imperialism of the Roman Catholic Church - because of this, most modern Necromancy still focuses on themes of divination and spirit summoning. Literally Raising the Dead is not common in the aforementioned necromancy - for that, you have to look to other sources. One good example is the Saga of Hrolf Kraki from Norse Mythology. Without getting into the specifics, a Viking King has an epic show-down with his sister Skuld, who is a powerful master of Seidhr (viking sorcery), and other, darker magics. Skuld eventually turned the tide of battle using her mastery over life and death; through her magic, she was able to return any warriors who had fallen in battle to a semblance of life and send them back to the fray. It's worth noting that Skuld is the badguy in this story (of course, this is Norse Mythology, so bad-guy/good-guy dichotomies get a little wonky, in this example, Skuld is getting revenge on behalf of her beloved husband for a a number of dishonest manipulations by her brother Hrolf, a very Viking motivation for murdering, so you could argue she's justified). As to why we find Necromancy unsettling - and now we're talking about Skuld's Necromancy here, not just divination - well, for starters, most cultures assign a certain level of ceremonial significance to the posthumous body. Just about every culture throughout history has had various rites associated with committing a loved one or community member to eternity, and many have gone so far as to associate the way that the body is handled during funerary rights with the way the spirit is received in the afterlife (if it is received at all). Viewed in this light, and tempered by the anti-sorcery rhetoric of the Abrahammic Religions (which were undeniably significant in shaping the evolution of many of the world's cultural views on death and the afterlife), it's easy to see why many people are attached to their bodies or the bodies of those they care for. Desecration of the dead is considered abhorrent in most modern societies, and it's hard not to interpret most forms of necromancy (whether you're actually animating the body, or simply using it as a ritual component) as a form of desecration based on current mores. Remember, though, that the Egyptians mummified the dead by ripping their brains out through their noses, bottling their innards, and filling them up with potpourri; a ritual that would almost *certainly* be considered desecration by today's standards, but was the highest honor that could be bestowed on a corpse in that time and place. **Maybe it's not so bad, though...** *So*, getting around to the point; again, the hatred of Necromancy in our societies is mostly cultural and religious - as the writer building your world, it's up to you to decide if these same ideas have taken hold there. There's some evidence that the ritualization of funerary rights began quite simply with the need to bury the dead because corpses are not a good thing to have lying around the camp. In general, human societies have had compunctions about eating their brothers and sisters, and if you're not going to eat and utilize it, you really only have one choice, dispose of it. Necromancy (Skuld Style) opens up the possibility for early cultures to make use of human corpses without having to eat them, thereby engendering a cultural norm. Of course, there *are* examples of cannibalistic human societies, so maybe in your world cannibalism was not uncommon, Necromancy came later, and by that point, it was generally considered normal to use human corpses for their potential value. If you want Necromancy to be *common* in your world, you'll need a general cultural acceptance of it, which should be easy to write with some creative history, but there are other options. A few. 1. Necromancers are feared, but respected. Necromancers are viewed with some suspicion by most, but the Order works hard to make it clear that it's more valuable than it is dangerous. By consensus, Necromancers don't *make* new corpses, they just use the ones that turn up normally. They contribute to the general welfare by having skeleton servitors (zombie servitors are just *nasty*, and unhygienic, to boot) perform community service, and undead chain gangs dig ditches, pave roads, construct dams, aqueducts, and other buildings. In fact, life is usually pretty swell for your normal person, because most of the menial things are handled by the Necromancers; and the Kingdom is safe because its neighbors fear its necromantic guardians. In exchange, the Necromancers enjoy a steady supply of freely given subjects for their work. For your needs, this means that while people are a little icked out by the work of your protagonist, many will be willing to offer him a level of respect or courtesy befitting his association with the Necromancers they have come to rely on. 2. Necromancers are feared, but not hated. Noone can place when necromancy first became a thing, exactly, but the necromancers have been around since basically the beginning. Like anyone else who practices magic, the mundane people of the world look dubiously on them for possessing an unfair advantage, but the Necromancers have mastered the most important of Machiavelli's maxims. It is safer to be feared than to be loved; and it is important not to be hated. The Necromancers know that if the common folk - so numerous, the common folk - turn against them, it will be a bad day. They therefore take pains not to make themselves despicable, but they do not brook attacks or intrusions on their sanctums, responding with force and swift justice. In turn, everyone else has learned that the Necromancers are not to be messed around with, but since the Necromancers don't do *insane* things like raise undead legions and terrorize the living, the fear of reprisal is enough to keep most people from messing with a traveling necromancer. 3. Indoctrination. Maybe it didn't start this way, but the Church of Death now employs Necromancers. The Church is responsible for ensuring that a soul sees its way into the afterlife, as compensation for this valuable religious service, they take possession of the corpse. The Church maintains a standing garrison of undead warriors to protect its temples and the towns they stand in; it also patrols the streets and keeps the peace. Skeletons stalk in throngs around Wardens, acolytes who oversee the undead work-crews. The Church is essential, and though it rules with an iron fist and brooks no opposition to its teachings, it commands loyalty in all the usual ways. People are just used to the dead, by now, really. 4. The Undead have never been uncommon. In a world where sometimes, the dead just decide not to stop living, coexisting with such beings would be quite ordinary, as would the specialists who deal with the magic animating the undead. 5. Maybe they've just had a long time to get used to it. You can get used to a lot. Maybe in your world, Necromancers *were* regarded in a negative light, but the Liche King changed that by showing that just because a guy raises the dead, doesn't mean he wants to eat your flesh and slay your family. And why not? The Liche King has been in charge for a long time, and the Kingdom hasn't burned down or been smote from on high, or anything. Closing note. This question largely has to do with cultural perceptions. It's therefore hard to say how we might feel about Necromancy if it were, you know, actually a thing that could and did happen. Portrayals of Necromancy haven't helped at all, really. You've already touched on this by pointing out that usually Necromancers are mad, evil, or both. Generally they're egomaniacal, murderous, and usually they're interested in conquering the world - typical comic-book villains for typical comic-book villainy. It won't be hard to bring a more nuanced angle to this aspect of fiction. What if, and I know I'm being *speculative* here, but *what if* there was a necromancer (or even more than one!?) who *didn't* want to conquer the world, slay all the living, and reanimate their corpses to go to his insane tea party? What if he had good hygiene and expected the same from his unliving tools? And what if he knew how to give a skeleton a spade or hammer instead of a sword and shield? Some more good questions to ask going into your world-building: How long has Necromancy been a thing? Is there other magic, and how are other magicians regarded? Is there cosmic good and evil in your setting (our world is mostly grey and grey, but in The Lord of Rings there are obvious good guys and obvious bad guys, who go along with the associated gods - the same goes for most other epic fantasy settings)? If Necromancy is *generally* tolerated, are there some who rail against it? Is there a god who condones or even sponsors necromancy, what about one who opposes it? Is Necromancy accepted everywhere, or just in one region or country? [Answer] The main reason it is frowned upon across almost every culture is that people don't take well seeing one of their relatives forced out of their grave and used as cheap labor/weapons/army... However, I see two ways to go around that: * Have your necromancer ask the relatives, or even better if your world allow it, the dead himself if he will let the necromancer raise him. For example, you could have your necromancer negotiating with peoples to get access to their corpse once they are dead, which would allow you to put more emphasis on the peoples themselves. If you have a way to talk to the dead, a system of contracts with the dead would kill two bird in one stone: the corpse can't be raised without the soul's authorization, and you can have interesting relationship between the necromancer and his "army of dead". * Have necromancy being well known and understood, so that there is no attachment to the body itself, and that "desecrating" the body of someone is not frown upon. You may study the Talos Principle about this, in a lot of culture, the body is given by god and sacred, but in a culture where the body is only a tool, there would be way less, or no taboo on raising corpse left and right, since they are only bones that have no use. [Answer] # Summary Alright first of all, thanks for all the replies. I myself find necromancy a pretty interesting subject. I've seen some awesome and open-minded answers from this great community. That's why I've decided to answer my own question containing the reasons I found most helpful understanding and the tips most interesting that could help regarding the world I'm building. ## Reasons why necromancy could be considered evil **1. Overall terror** > > Raising an army of any sort to terrorize the countryside is considered a pretty evil act. > > > By: [sphennings](https://worldbuilding.stackexchange.com/users/26175/sphennings) > > Dead people are unsettling. They look like people, but wrong. It gets even worse when they do things dead people aren't supposed to do, like make noises or move — something that is known to happen with real corpses. > Besides the uncanny valley effect, corpses are also known to stink and spread disease. When people see your zombie soldiers, they'll be horrified. > In fiction, using tools that are considered gross signifies an evil character. Even relatively harmless symbols like spiders, snakes or blood are rarely associated with good characters. > > > By: [KWeiss](https://worldbuilding.stackexchange.com/users/19086/kweiss) The protagonist raising an army has no intend terrorizing any neutral beings at all. But like in most medieval societies, no peasant likes the mobilization of armies throughout his farm. This is almost impossible to avoid, especially if these armies are... well... dead. On regular basis its unsettling to even look at, let alone work with. **2. Transgression of religions** > > To raise the undead is to desecrate their corpse and grave. This could also include transgressions against any religious institutions involved in the burial process. > > > Pillaging the countryside, desecration, and acts against religious institutions are considered evil in most societies. > > > By: [sphennings](https://worldbuilding.stackexchange.com/users/26175/sphennings) Just like the real world, the most active religion in this world has a lot in common with Christianity. Have researched some more I found that the Bible doesn't really like necromancy. Necromancy is defined as the conjuring of the spirits of the dead for purposes of magically revealing the future or influencing the course of events. In the Bible, necromancy is also called “divination,” “sorcery” and “spiritism” and is forbidden many times in Scripture. No doubt the protagonist will have some problems fighting evil with risen spirits while the dominant religion is totally against it, and sees it as evil. **3. Harming the used souls** > > Here's one no one else has brought up; the souls. very often, necromancy involves binding the souls of the dead to their corpse in a way that isn't... pleasant for the soul involved. After all, if it was simple animation of bones and flesh, it'd be a golem, not a zombie. In many fantasy worlds, the existence of the soul is something that must be taken as fact, and those souls must be treated humanely, that is, allowed to move on. A zombie is more than shambling flesh; it is a torturous prison for what used to be a sentient being. It can build all the orphanages you want, you're still using labour derived from unwilling souls. > > > By: [monoRed](https://worldbuilding.stackexchange.com/users/28573/monored) Maybe also one of the points I should have been more specific about. The idea of necromancy (like in most fictional worlds) is that risen undead need a soul attached to work. When binding these souls to bodies that are in a lot of fighting, labour and just unpleasant events, you might make a few angry or even suffer. Thank you for making me realize this. ## Tips to make necromancy (look) less evil **1. Do nice things with the undead and honor them** > > One way I could see to get around this is to make the zombies not very corpse-like at all. Maybe they're skeleton soldiers, but the important thing is that you can't tell which individual they were when they were alive, and that they don't stink, don't rot and don't spread disease. It should also be relatively clear that they're just material beings and the soul of the person in question is off doing whatever souls do in your setting. > > > By: [KWeiss](https://worldbuilding.stackexchange.com/users/19086/kweiss) > > If the soul is not suffering, then there is no moral reason that animation is wrong except for respecting property rights. The corpse, by most laws of inheritance, defaults to the ownership of surviving relatives who are free to do with the corpse as they wish. If they want to donate the body as a laborer in order to pay off bills rather than deal with the additional costs of a funereal, that is their right. > > > For an example of how arbitrary the morality is, look no further than the Necroscope series. The protagonist is a medium or "necroscope" who speaks with the dead and may call upon them to rise from their graves and assist him. The antagonist includes "necromancers" who mutilate corpses to learn their knowledge, which the dead souls feel despite being dead. Otherwise the dead don't care about the condition of their unfeeling remains. > > > By: [Anonymous](https://worldbuilding.stackexchange.com/users/20781/anonymous) > > Let donating your body towards charitable labor be an acceptable funerary choice. > The honored ancestors of the living are animated, decorated and cared for by their descendants and used to construct monuments/temples to the wisdom of their generation. > If the animated corpses are intelligent and communicative people could employ necromancers to awaken ancestors for important events like births, marriages, baptisms, deaths, etc... > > > By: [sphennings](https://worldbuilding.stackexchange.com/users/26175/sphennings) Some creative idea's by sphennings I really like. This will make the society much more appreciate what you are doing with their dead ancestors, and are much more willing to let them fight for you. The terror level really decreases when you decorate the undead with pretty tulips and leave all the rotten flesh out. Also not harming the souls part is pretty important. **2. Convince religions and society there is a greater evil** > > These beasts eventually attack the frontier towns, capturing people to eat due to their love for human flesh. They eat humans by absorbing their fluids and all soft parts, leaving only the hard bones, without knowing who was that person. They leave the remains of the dead in the middle of forest/fields/whatever that exists between the beasts lair and the human civilization, so after the beasts retreat to their caves the survivors can recover the bones to bury them, without knowing who is who - which avoids the negatives of "seeing my beloved ones as skeletons". > > > This situation continued for centuries, so society evolved to live in these conditions - including culture and religion. Then a new religion (or other kind of social movement, maybe just a new branch of existent religions) emerged - a religion where hatred for these beasts was a dogma. They said: "The most desired thing for a spirit of someone killing these beasts was revenge - revenge by their own hands if possible". This civilization starts to change their view of necromancy - not only because their attitude changed, but because only the dead can approach the beasts to kill them without being "killed" - since they are already dead. So, they start to develop necromancer units to raise the victims of the monsters to destroy them as armies of skeletons! And your hero is one of these necromancers. > > > By: [Brian Hellekin](https://worldbuilding.stackexchange.com/users/30353/brian-hellekin) Only answer I found regarding the religions problem, which I found to be one of the largest. Very well written. ## Conclusion In the end it all just comes down to the world's perspective you build around a specific subject (duh). But in reference to the world I'm building, these are some pretty decent and creative solutions. I want to thank you all again for the great answers. P.S. I hope all my thank you's won't be removed. [Answer] How about you only raise animals? If you have a strict no human rule, it would still be gross, but only PETA would think it was evil. Then you can have evil necromancers that *do* use humans, that the good necromancers try to stop. [Answer] Call it resurrection or something else. Make the population resurrect the dead as part of their culture. That way the towns people will think it's fine and the dead will expect to be brought back at some point. Explain how it puts the right persons soul into the right persons body and brings all the cells back to life and what not at its highest forms, or explain how there's a difference between ethical and non-ethical necromancy. You can always explain how necromancy isn't bad or you could attempt to just roll with it, but if you call it necromancy then you're going to get the connotation of bad along with it no matter what you do. If you make ethical necromancy part of the culture then you should be able to justify whatever you want as good necromancy. [Answer] Instead of stealing bodies pay people for use of their body after they die, that alone will go a long way to a better image. Or if he can talk to the dead he can negotiate for after their death. "20 gold pieces to my family who live *here*, and you can have my bones." Play it up as service to the community and you may even get volunteers without payment. Taking the time to bleach bones and clean off the rotten flesh will help too, so they are not a disease ridden mess. Make it a point to keep a signed contract for your undead, or come up with a guild that regulates it with some kind of badge or stamp certifying legal necromancy vs grave robbing assholes. As long as he is taking them against their will it's no different, for the moral perspective of most of the populace, than taking slaves and forcing them into your army. [Answer] I think the best way to remove the stain of evil on the practices of necromancy is to rework the way the dead are treated and perceived in your world. There have been a number of comments already about why the practice of digging up such corpses is reprehensible, but those do not necessarily apply if the dead are more accessible. By burying the dead, they are locked away. It implies that we expect them to remain down there. Instead of burying them, put them in a location easy to walk out of. For example a crypt with a front door, where the dead are not stored in coffins, but are positioned as if they are sleeping. Why would the dead be buried this way? Because in this world/culture/religion, it is considered an honor if a corpse is reused by a Necromancer. Seeing your dead parents fight wild beasts doesn't have to be an affront if the people expect it - or even hope for. As for the gory parts and the issues with free will, that can be solved by, for instance, having a necromancer employ good-aligned spirits to inhabit the corpses and do his bidding. The spirits could 'patch' the decaying corpses with ethereal material. If the face of the previous owner of the corpse is a problem, have the spirit conjure a face for himself. The spirits could refuse service if the necromancer wants to use them for evil purposes. The list of options doesn't end here, once you change the rituals in your world to be less grim and the status 'dead' to be less final. [Answer] **Loyalty and devotion, forever.** Your peaceful farming country has always revered its ancestors. Every ancestor has worked hard for their entire life trying to improve the lives of their children, children's children, and so on. The Ancestors have always been there to help, especially in the spring and fall when the local necromancer would be able to temporarily reanimate them so they could help with the planting and harvest. Work and devotion to family is a foundation to the society, even in death. A party would be held as the dead re-interned themselves until next time. All was well with the world. Then those Outsiders attacked. Who are they to say that animating the Ancestors is evil? Who are they to drown the local townsfolk, as a "test" to see if they are "witches" (what's a witch anyway?). When the local necromancer is found by the Questioners, the whole family is to be executed. Unknown to them, they missed their little boy who was out playing with the squirrels. Having lost his whole family to these red-pointy-hatted Questioners, he decides enough is enough: His father had taught him the basics of necromancy and he would do all he could to enact his revenge. He starts with his little reanimated squirrel. Later he learns how to animate several at once. With practice he graduates to humans, and even bears. Over time he understands how to communicate with those recently dead to get information of defenses from those who were killed in those vile Questioner dungeons. He eventually can reanimate the dead to look like they are still alive, fully controlled by him! And then the ultimate gift: a Head Questioner dies of old age in his sleep without anyone knowing but the boy. He can now take down the entire organization from within! [Answer] Maybe something that can throw a completely different light on this is the TV-series "Pushing Daisies" (think of this as a romantic comedy series). Here, the protagonist has the power to raise a dead person back to life by touching the corpse once. If he touches the corps a second time, the person dies again and can not be resuscitated again by the protagonist. There is one trick to it though: if a person is risen from the dead, but not touched again (died a second time) within a limited amount of time (30 seconds in the series), one random soul dies in the vicinity (can be an animal as well). This brings up several dilemmas (such as not being able to touched a loved one if you've resurrected him/her) but also opportunities (solving murder cases). In this case they skip very lightly over death (I described it as a romantic comedy, can't do that if there's too much darkness overhead), but some of the problems related with "necromancy", especially this special case, are touched. As for an answer to your question: in this series they do not frown upon "necromancy", and the character is most definitely not an evil protagonist. [Answer] Talking to the spirits of ancestors is rarely depicted as being evil, but then one wonders if that isn't simply because western authors tend to depict anything non-western/from extinct cultures and christian as awesome-cool-quaint. Ancestor spirit thing-dudes in conan-esque cultures, in oriental depictions and american indian are not normally evil, whilst ouija board and egyptian stuff is. Don't really think there's much logical consistency, except stuff like the egyptians practised human sacrifice. But anyway.. Necromancy etc is taboo not because it's bad, But because people imagine it to be bad. Have you ever met a necromancer? How would you feel if it was ubiquitous? Any ideas? Concerns about economy/cheap labor are a little silly, coz you're imagining that from the perspective of an economy in which necromancy does not exist. Like an earlier answer "people would start killing themselves in order to earn their family money.." makes no sense, as they can work whilst alive..or learn to become a necromancer, presumably. If you want to prevent such things, just have some plot-ban on suicides, such as something particularly nasty happens to their souls that simultaneously prevents their bodies being raised or bound. You could use a similar mechanism for the victims of murder or etc If you have pantheistic/domain Gods, your Gods of murder & suicide could be particularly jealous of people using souls which should go to them an so ban necromancy on them. Whilst souls/bodies of people that die of nat. causes or in accident, pursuit of faith, etc could be more freely repurposed. In this way, if these things are part of common lore then people's views on the use of corpses/souls would be altered somewhat. gl. [Answer] It all really depends on things like *how does necromancy work in your world*, *what are the historical implications of necromancy* and *how common is necromancy in your world*. Firstly, *how does it work*: * If necromancy requires something others have and takes it by force (soul, life force, body), it will be very hard to justify it as "not evil" for the society at large. * To contrast: if the undead warriors can *choose* to serve him, it's a whole different matter. Hell, you could have expansive side story lines where the protagonist goes to great lengths to get ancient heroes to join his cause. I know you included the line about raising "without permission from the dead", but I'm just covering other possibilities here. * If necromancy has no cost to others and possibly comes at personal cost to the the main character, it becomes easier to justify. Second, *historical implications*: * If the setting has an ancient hero / deity who raised the dead to combat some ancient evil, well you have a *precedent* for your protagonists actions. Obviously, the opposite is equally true: an ancient evil who focused on raising the dead makes is less plausible for people to hail him as a hero. * Necromancy being seen as evil has a lot to do with how people have historically viewed corpses as. In our modern culture we have ceremonies to send the people to afterlife and all that. If your culture has similar rituals, well, bad news for your hero. * As en exception to the above, consider warrior burials where the corpses are preserved, possibly for some future cataclysmic event, well, your hero can argue he is just there to raise them for the righteous fight, possibly in name of some deity or another. Lastly, how *common* is necromancy: * If necromancy is unheard of or practiced only by enemies of the culture in question, you're going to have hard time justifying it, especially if we're talking about literal half-rotten zombies and skeletons. * If necromancy is more common though, possibly even legalized and regulated, it is much easier to temper natural fears over it. Many of the the things we consider common place today would be seen as dark and evil sorcery just a few hundred years ago. [Answer] Have only *restless* souls be able to be raised, as an act of redemption, after which they are thanked and sent on to their eternal rest. Other popular examples: * The "[Army of the Dead](https://en.wikipedia.org/wiki/Dead_Men_of_Dunharrow)" in Tolkien's Lord of the Rings. * In "[The House of Hades](https://en.wikipedia.org/wiki/The_House_of_Hades)", book 4 of Rick Riordan's popular "Heroes of Olympus" series, a legion of ancient Roman warriors is raised to fight an overwhelming foe. I suppose you couldn't use this ability too often, at least in the same immediate area, or you might run out of restless souls. [Answer] Also consider a culture where bureaucracy is supreme. **Anything is allowable as long as you have the proper paperwork and permits.** Different kinds of necromancy have different forms required, of course. Certain forms would allow someone to hire out their mortal remains or departed soul *after death* but be paid *before they died* or they could arrange to have their heirs paid. * An animated corpse with no connection to the soul of the deceased would be the cheapest since you were hiring only the mortal remains, not the soul. * An animated corpse with the soul attached would be more expensive since you were hiring both body and soul, with the soul diverted from its afterlife. * A soul that hangs around without its body could require special considerations, such as a vessel to which it must return periodically. * Pay rates could vary depending based on the physical capability of the corpse. Temporary summonings would be different than long-term ones. There would (of course) be multiple forms for every conceivable situation. Some examples: 1. The deceased gave permission before death. 2. The deceased's next of kin gave permission after death. 3. Convicted criminals could be required to work *after death.* 4. Forms could grant permission to contact the dead and ask permission to raise them. 5. Forms could grant permission to summon the dead without asking first. 6. Forms could even grant permission to summon those who forbade it. 7. Debts could be discharged by post-mortem work. There would be government inspectors whose job was to guarantee that all paperwork was followed and all agreements with the deceased (or their heirs) were followed. [Answer] **Necromancy** is used 'for good' sometimes. Following Arthur C Clarke, who said "Any sufficiently advanced technology is indistinguishable from magic.", think about organ donorship - the 'magical' use of corpses to sustain the living. In ancient magical traditions, the perception of what is 'good' is far more related to intention/outcome than the actual methods by which it is obtained. Ideas of absolutism tend to be rejected because the metaphoric / allusional nature of the phenomenal world is a central thesis of magical traditions. It's not just intent, of course. It's also insight (or wisdom). One must know what the consequences of one's actions are. But if one has powerful insight then the ability to use any form of magic for beneficial purpose is available. In general, there are many divisions of necromancy - some of them are relatively benign, such as using corpses as medicine (see above) or for divination purposes; whereas corpse-raising (eg. zombies, or similar) are generally considered to be terrifying for soldiers to fight - because they find themselves fighting their own former comrades, and if they die they become just another soldier within the zombie army. In general though, such armies only belong to fiction. Those who have claimed to raise the dead say that it is a long, arduous, and painful process - far more like Dr. Frankenstein's work (he was, after all, a necromancer of sorts) than just waving a magic wand. [Answer] Most of this is tips how it could work... But some are reasons why it's viewed as evil too. One core reason why it is viewed as "evil" is probably the reason those characters use it for. I'm not sure what Sauron did tbh (Ring wraith?), but the Lich King used them as an army against all living. That's quite a good reason for the living to be pissed. The undead in that same universe however view necromancy as a means of reproduction. They can't procreate but can raise dead to increase the number of their own "race". I'm not talking about the mindless Scourge here, but the Forsaken. I assume your people is not undead, so you might have to think for another reason why they might "like" the idea of being raised. A note at the warcraft lore, there was the cult of the damned. They hoped to get turned undead and sacrificed theirselves in the hope to be raised again. So they were hungry for power and didn't have problems adjusting their morale. Also, another good reason would be some kind of patriotism. Serving even in dead. You could add some rituals etc. Embalming to preserve the body. Burial in armor to be ready when needed. If your undead preserve memories this is almost like resurrection. Do they still decompose? If they are, they are an expiring army that can be used "one time only" or "for a limited time". Embalming and preservation might take a bigger role then. Maybe even create a caste of embalmers, that tend to the dead and keep them ready for the time when they are needed. This could be a honored job or a high religious position. If they don't decompose they technically turn immortal upon being raised. If they even keep their personality that's quite a good incentive to earn being raised. The entire culture could focus their life to be raised and stay "alive" forever. That might sound a little dark to us, but if there was no stigma to it by our culture it could easily be normalcy. Religion in general could take a major role here. Usually our real life religions want their deceased to rest in peace. Raising them to fight/work is not really resting, especially not in peace. So that's a good reason to see those who disturb the dead to do something wrong/bad. If however your god dictated servitude even in dead and being raised is an honor people who didn't manage to be heroes in life get a second chance. You could even create cults that train in life and then kill themselves at their peak. Getting prepared and tended to, embalmed and all that stuff, just to be ready when duty calls them from their tombs. So TLDR; Necromancy is viewed as bad from our cultural perspective but there are tons of reasons why it could be an honor in a fictitious culture to be raised again. [Answer] Can do (kind of). * Convert self into lich. Do this before raising any other dead. * Carve or transfigure marble blocks into statues of yourself * Stone to flesh statues of you * Raise dead on resulting corpses Since all bodies are yours and you are your own closest relative there's nobody to complain to. [Answer] Three things in your question make it hard to imagine your protagonist as the good guy: 1) the term "necromancy" itself, 2) the "without permission" part of the powers and 3) the "manipulate souls" part. If you re-branded it "communing with the ancestors," if it required the consent of the dead, and if it didn't involve manipulating souls, it might be easier to sell it as a net positive. In other words, it's not just the powers themselves, it's the attitude with which they are used. ]

[Question] [ # A Little Explanation I have come across many books and trilogies based on the premise of a war torn United States. The latest of these is [Burning Nation](https://rads.stackoverflow.com/amzn/click/com/054554873X) (link to Amazon page) in the Divided We Fall trilogy by Trent Reedy. This is a great book and features a standoff turned violent between the state of Idaho (later Texas joins) and the federal government over the issue of enforcing a law that forces citizens to carry a traceable ID card with them at all times. While I don't think it is plausible that Idaho (of all places) would be the first to defy the federal government, I think the premise of a civil war over such a monumental violation of privacy is still sound. This is merely one scenario that needs to be taken into account when formulating an answer. # The Question Which states are most likely to rebel against the US in the near future (meaning America is in the same economic position as it is now) assuming a federal law is passed that violates American constitutional rights to such a degree that entire states (state legislatures included) would rebel? The rebellion should preferably be a war of independence fought throughout the US. [Answer] **It's Texas.** The big problem with an entire state rebelling is the rest of the US starving them of resources. Like, for instance, *electricity*. Most people aren't aware that a majority of the United States is electrically connected by three major power grids. Many of the states in each grid do not have the ability to produce enough power for their state alone. Except Texas. Texas is its own power grid independent of the rest of the United States. [](https://i.stack.imgur.com/3aNQv.png) [Texas could (try to) secede](http://www.texassecede.com/faq.php) from the United States and maintain its resources for [electricity, oil](http://www.eia.gov/state/?sid=TX), [water](http://www.waterdatafortexas.org/reservoirs/statewide), and [agriculture](https://texasagriculture.gov/About/TexasAgStats.aspx). --- **[Long live Cascadia](https://en.wikipedia.org/wiki/Cascadia_(independence_movement))!** The second most likely (at least the one I'd support) would be a collection of Oregon, Washington, and part of Canada (maaaybe part of Northern California if they don't try to move to Oregon). [Answer] **Alaska** There is, of course, [a strong Alaskan independence movement](http://en.wikipedia.org/wiki/Legal_status_of_Alaska) led by [the Alaskan Independence Party, an extremely large (relatively) third party](http://www.akip.org/faqs.html). It has [over 15,000 members](http://io9.com/5923080/10-movements-to-secede-from-the-united-states). Interestingly enough, among their [key principles](http://www.akip.org/platform.html) are the desires to uphold a person's Constitutional rights and state/individual rights. It sounds like they would be eager to go for independence in the scenario you described. In fact, the AIP got enough support to introduce a proposal for secession on the fall ballot in 2006. They have a decent amount of strength, for a secessionist movement.1 Alaska as a whole is also apparently a stronghold of [libertarianism](http://en.wikipedia.org/wiki/Libertarianism). Things in favor of Alaska in the case of secession: * There is a buffer zone between Alaska and the United States (namely, Canada, who may not want to get involved). * Alaska has oil and other petroleum-related resources, which could help build a strong economy, especially if drilling spreads. * There is some support (from Russia/Russians, not Alaska/Alaskans) for Alaska becoming a Russian territory (as it once was), indicating that Russia might support Alaska in a war. * Alaska is pretty isolated from the United States. --- 1 The AIP is certainly not strong enough at present to pull off something like what is described, but the movement is comparatively strong, and given that the question simply asks for the most probable states, the point should be valid. [Answer] **(1) Texas.** I have no problem imagining Texas seceding from the United States. Obviously the vast sentiment is against secession, while those that are for it are vociferous, and those that are against it, just think it's silly. The reasons for Texas' departure would be a strong economic connection with other countries, such as Mexico and the Gulf states; as well, there are romantic and prideful notions. Texas is also the second largest [donor state](https://en.wikipedia.org/wiki/Federal_taxation_and_spending_by_state), and would do well economically. **(2) Alaska** In addition to HDE's answer, with a relatively low population, and a very seasonal population, there's less chance of opposition to a strong movement. **(3) Hawaii** Hawaii receives a major source of their economy from on-land agriculture and tourism (from overseas as well). The great distance from the contiguous US makes it more convenient as well. It would have to be a peaceful secession, resulting in charging the US for keeping defense personnel and economy there; as well as commercial, etc. flights to/from the US; and trade for specialty items. **(4) Washington, D.C.** This would be interesting (being the capital and all). The city-state that is taxed, but with no representation in the United States Senate. Becoming an autonomous country, but holding the administrative functions of the US Government, would benefit them nicely, but I don't know how America will negotiate having their administrative center "overseas". WDC would not try anything daring, though, because they're almost totally landlocked by a very powerful country. They also have the highest revenue per capita of any of the "states;" they would do well to trade internationally and with America. **(5) Red vs Blue** As our country gets more politically polarized, the movement to secede becomes stronger and an alliance of some of the key states like Texas, Colorado, Arizona and the 'deep south,' results in negotiating a movement to secede. The states that are not "red states" or "blue states" but rely on more powerful states end up flipping to that color. For continuity and for that last sentence, *I've made some changes* and taken the liberty (ha, get it?) to adjust for you the United Divided States. [](https://i.stack.imgur.com/mREG6.png) [Answer] Rather than announcing several states, I think you should consider factors that states would take into account before seceding: ### Ports and access to open water Similar to land that has no access to roads, a state without an ocean border or access to the same is not going to last long in the world's economy without very, very good neighbors. ### Self sufficiency A state that cannot feed itself without imports is likely to quickly capitulate. Not only food, but fuel, water, and electricity are all critical resources that, if curtailed, would leave a lot of unhappy citizens, a situation that would be easy to abuse externally to get the state to capitulate. This also includes means to defend itself. ### A low degree of ties to the federal government There are military bases, missile silos, highway corridors, etc that are all operationally vital to the US federal government, and would be hard to "kick out" if the state chose to become a nation. Even if they can defend themselves, how are they really going to pose any threat as an offensive action against a hardened military installation? And if you don't get rid of them, there will always be traitors in your midst. The catch-22 to this is that the less populated portions of the US have a surprisingly high number of these because they are harder for enemies to find and disable in a mutually-assured-destruction situation, and there are still a lot in populated areas. So there are few states where this wouldn't be a big problem. The federal government and military are firmly entrenched in almost every US state to a very large degree. It would be hard to physically get rid of them and truly secede. ### A moral imperative to secede I don't think money or many other concerns are going to cause a populace to rise up en masse against the federal structure that provides so many benefits. It will truly take a significant moral issue to provide the impetus. Self-determination, privacy, anonymity are the tip of the iceberg. What if the federal government subscribed to an extreme version of children's rights, that meant parents could no longer teach their children anything except the state-approved education? No religious instruction, relative morality, strict authoritarianism perhaps. What if the environmental lobby had its way and prevented people from managing their own land, for instance banning all drilling (water, oil, gas) and access to surface water and rainfall except under the control of local utilities. You could no longer have the freedom to be self sufficient - if you wanted water you had to pay for it. A simple disagreement isn't going to cause succession because you won't be able to get enough people on board - but a moral imperative to protect their basic freedoms and ability to determine their own path through life might get enough disagreeing people on one side of the fence to act together against the federal government. ### A distinct difference from the rest of the nation This one is probably the most difficult to achieve. If the Federal government is doing something that Kansans will oppose, why wouldn't their neighbors also oppose it? Something with a strong enough impetus to meet the "moral imperative" above is likely to affect the entire nation. So what are you going to find that binds the people together so strongly, that other states don't also have? Natural resources might be one. Take, for instance, The Great Lakes. If emptied and trucked to California, they would single-handedly meet all of california's water needs for the next 5 *centuries.* Of course, with access to free freshwater, they would increase their consumption and it would be gone much faster, but I don't think people realize how much water is in there. If the federal government and the rest of the US decided that The Great Lakes belonged to the nation to be used however it saw fit, and Canada decided the same and split the lakes between the two (so there'd be no international conflict) then you'd probably see several states oppose it very strongly - possibly to the point of seceding if they thought they could win and save the lakes against both the US and Canada. Alternately, what if the federal government targeted states with possibly good reasons - FEMA decides that with the ocean rising, and the worse weather, they are kicking people out of Florida - no more federal services will be provided after a tapered cutoff date for people living in those areas. No air traffic control, highway funds, etc. In a sense, it'd be the US seceding from florida - at that point the state and its citizens might choose to form their own nation to fill the gap. Maybe rather than hurricanes and floods they worry about earthquakes and demand that people move away from all known fault lines - this will affect california disproportionately. [Answer] Just an idea: a French RPG, called C.O.P.S, developed the idea that California would fight for Independence after a rise of conservatism in the USA. If I remember it correctly (the game was created in 2004), Arnold Schwarzenegger was elected president, but his mandate was terrible, so the next candidate was a rigorist, willing to bring back "morale" and federal control over the country. He was mostly supported by the east coast, and passed some laws as controlled internet (each user would have to enter their personal credentials to access to any website, and the NSA would be able to track people based on that), pornography infringement, drug war enforcement and so on. And after his reelection, California decided that the state would be better off without the federal government, and declared itself to be the Republic of California. American army gathered at Californian border, but the war was avoided when Nevada, Hawai and Alaska declared themselves part of the Californian Republic too. (Nevada joined because Las Vegas suffered as much as Los Angeles from those strict laws, and the other two joined because they felt they would have more influence in this young state, so more leverage to pass laws in their favor). The RPG is set in 2030, so 4 years after the independence, the situation is very young. The USA are watching very closely the new borders, and probably infiltrate the young Republic. California enjoys its new independence, and lives in an hedonistic lifestyle, trying to forget about the warmonger neighbor, the earthquakes getting more frequent and stronger, and the increasing criminality that uses the weakness in the new administration to expand their activities. Unfortunately, real life events proved that this scenario didn't happen. California is having a terrible economical crisis, the democrat candidate has been reelected, and Arnold did a new Terminator movie... [Answer] I'd go with the consensus on Texas. For one thing, its governor has [openly talked about doing so](http://www.newrepublic.com/article/114419/texas-secession-rick-perry-americans) (when not running for POTUS), and there's been some talk about the merits of letting them do so. It could make a viable country on its own, as it had natural resources (particularly oil), a decent economic base, and good ports. [Other "independence" movements](https://en.wikipedia.org/wiki/Secession_in_the_United_States#1980s-present_efforts) I know of that are remotely plausible as functional countries are California, [Cascadia](https://en.wikipedia.org/wiki/Cascadia_(independence_movement)) and the hate group [League of the South](https://en.wikipedia.org/wiki/League_of_the_South). IMHO if California were to secede, the rest of the Pacific Northwest would probably want to go with it. That might even include the trans-Rockies portion of Canada. It has otherwise been openly talked about recently in Alaska, Florida, Georgia, Hawaii, New Hampshire, Vermont, South Carolina, North Dakota, South Dakota, Nebraska, Wyoming, and Montana. (about 1/3rd of US states, but this list probably isn't even complete) My personal favorites amongst the unlikely candidates are [The Conch Republic](https://en.wikipedia.org/wiki/Conch_Republic), and [Lakotah](https://en.wikipedia.org/wiki/Republic_of_Lakotah). Proposed border of The Conch Republic [](https://i.stack.imgur.com/O1rur.png) Proposed borders of Lakotah [](https://i.stack.imgur.com/964S8.png) [Answer] My list would be: 1. Hawaii 2. Puerto Rico (Yes I know it is not a full state) 3. Alaska 4. Texas 5. California Outside of any ranking, Utah My criteria are: * Cultural difference: Hawaii and Puerto Rico are of recent incorporation and their cultural makeup is quite different from the contiguous USA. While in the contiguous USA most of the population came through Eastern USA, that is not the case of Hawaii and Puerto Rico. Both of them can claim to be victims of USA imperialism. * Geographical situation: Hawaii, Puerto Rico and Alaska have clear natural borders. As it could be the case with Texas, there are no issues of frontier countries depending economically more from neighbouring states than from the own state. No USA vital communication transportation routes would be affected. I have my doubts about California, from what I know it seems like a very active nuclues surrounded by hundreds of miles of underpopulated terrains (or directly desert). * Political: This works specially for Puerto Rico, since they are in a legal limbo (not a fully state, not fully USA citizens). Also slightly in favor of Hawaii, which was forcibly annexed. And against Texas, since black population probably will be quite suspicious of the reasons for independence (remember why did Texas secede from the Union last time). * Economy: This works against Puerto Rico, but benefits Alaska, Texas, California, and, to a minor degree, Hawaii. I have singled Utah as a religiously very conservative state. In this different narration, increasingly social rights advances (like gay marriage) cause a backlash that drives to secession, even if all of the other variables do not favour it. [Answer] Several answers have mentioned [Cascadia](https://en.wikipedia.org/wiki/Cascadia_%28independence_movement%29), I'll devote an answer to it. [It has its own flag and everything](https://www.youtube.com/watch?v=uEx5G-GOS1k)! :) [](https://i.stack.imgur.com/CKVaF.png) "Cascadia" is loosely defined, depending on who you ask, as Oregon, Washington, British Columbia and maybe parts of Idaho and Northern California. Cascadians share (*sort of*) an identity of civil liberty, environmentalism, low population density, small politics, and acting local. [Washington](https://en.wikipedia.org/wiki/Washington_Initiative_502) and [Oregon](https://en.wikipedia.org/wiki/Oregon_Ballot_Measure_91_%282014%29) made recreational marijuana use legal in open violation of Federal drug laws. So far, the Department Of Justice has declined to act. I don't think this will lead to secession, but it does demonstrate a willingness to openly violate Federal law at the State level. A Cascadian secession would likely be a peaceful one, a slow detachment from a Federal government increasingly unable to make decisions. Seattle (and to a lesser extent the [Silicon Forest](https://en.wikipedia.org/wiki/Silicon_Forest) of Portland) contain the home offices or major facilities of major technological and aerospace companies. This includes Microsoft and Intel representing a significant portion of the world's operating systems and hardware. They also have Boeing who produces commercial and military aircraft. Other industries include forest products, mining, agriculture, craft beer brewing, and high end coffee roasting. [Local power is available](https://en.wikipedia.org/wiki/Portland_General_Electric) through coal, thermal, [hydro](https://en.wikipedia.org/wiki/Bonneville_Dam) and (increasingly) [wind farms](https://en.wikipedia.org/wiki/Biglow_Canyon_Wind_Farm). Cascadia power companies [PGE, PacifiCorp and Puget Sound Energy are 3 of the top 10 renewable power companies in the nation](http://www.nrel.gov/news/press/2013/2211) and sold 1800 MWh in 2012. Defense-wise, the world will be dependent on Microsoft's operating systems and Intel's hardware which opens up economic and cyber threats rather than military ones. For military might [Bangor Naval Base](https://en.wikipedia.org/wiki/Naval_Submarine_Base_Bangor), located in Washington, is the sole base for America's US Pacific fleet of nuclear ballistic missile submarines. While seizing this base would be very unlikely, even gaining control of a single missile would prove a powerful deterrent. There's already been a book written about all this, though now decades out of date, [Ecotopia](https://en.wikipedia.org/wiki/Ecotopia). [Answer] > > The rebellion should preferably be a war of independence fought throughout the US. > > > To be honest, I don't think this is very likely in the near future. If you want a *violent* rebellion, any single state (or small group of states) that rebels will be quickly put in line. The way the modern US military works, most people are *not* serving in their home state, and have no special allegiance to it. So while there may currently be military assets in the state, they're not going to be of much use. The out-of-state people aren't going to fight against home, and will vastly outnumber the natives on almost every base. If need be, they can hold off the National Guard at the gates long enough to destroy equipment and airstrips before being overrun. This does indicate that some personnel *from* the rebelling state(s) will be in other states, ready to wreak havoc, but I suspect they would be quickly "put to the test" or simply imprisoned. If nothing else, branding someone as a terrorist and shipping them off to an undisclosed location works wonders. So the only realistic military force they will have is the state's National Guard, and hastily setup militia forces. I cannot reiterate enough: **This is not enough to take on the US military.** Not for long at all. I mean this will be shut down *very* quickly, and won't ever get to the "throughout the country" phase. This isn't the 1860s. Vehicles designed for destruction will be at the rebels' doors in minutes/hours, and completely destroy any real chance they have before it's begun. What's that? Texas has oil resources that supply energy? Boom! Not any more they don't. California has a large agricultural base? Not after carpet bombing both croplands and their tinder-dry forests. Once you destroy the means to resist and the supply lines, it's *over*. --- In short, you'd need a very large group of states for this to become feasible, and they would all need to pull out at basically the same time. This *may* be possible along ideological lines, but I doubt it. Most likely one state would be first, and others that were tempted would wait to see how it turned out before jumping in. It's possible that a foreign power would jump in and help out (whether on ideological grounds or just as an opportunity to screw with the US), but then we're talking about something a bit different IMO, which deserves its own space. [Answer] None of the answers consider the question of which political party the County Sheriff belonged. In most states, the local sheriff is the top law officer in the county. Both State and Federal law enforcement are subordinate to the Sheriff. By and large, many Sherrifs (and city Police Chiefs) are conservative as Republicans are generally considered tougher on crime. Another thing to consider is that the bulk of the [NCOs](http://en.wikipedia.org/wiki/Non-commissioned_officer) and unit leaders up to Battalion and Brigade are also more likely to be conservative. There is also a requirement for officers to question the legality of orders that violate the Constitution. The assumption that the Federal Armed Forces would be willing to follow orders that included firing on civilians or property is not preordained. "Southern Democrat" Sheriff's are often more conservative than Republican "Conservatives". Of the two, [California](http://en.wikipedia.org/wiki/California) is less likely to secede because they haven't shown they could balance a budget for the last 20 years. [Texas](http://en.wikipedia.org/wiki/Texas) is much more likely to secede. They have a historical perspective of having been a separate republic, even for just a miniscule amount of time. The Texas Tourist Commission has even touted Texas as "a whole 'nuther country". The mindset is there. If Texas looked serious in seceding, [Louisiana](http://en.wikipedia.org/wiki/Louisiana) would immediately join in. [Oklahoma](http://en.wikipedia.org/wiki/Oklahoma) and [Arkansas](http://en.wikipedia.org/wiki/Arkansas) would be right behind. [Arizona](http://en.wikipedia.org/wiki/Arizona), [New Mexico](http://en.wikipedia.org/wiki/New_Mexico), and most of [Nebraska](http://en.wikipedia.org/wiki/Nebraska). [South Dakota](http://en.wikipedia.org/wiki/South_Dakota) and [North Dakota](http://en.wikipedia.org/wiki/North_Dakota) would join and give both [Montana](http://en.wikipedia.org/wiki/Montana) and Wyoming time to think about it and themselves join. Outside of [Denver](http://en.wikipedia.org/wiki/Denver), most [Colorado](http://en.wikipedia.org/wiki/Colorado) counties would secede from the state, with possible exception of the county where the Air Force Academy calls home. [Answer] I just joined to add my two cents to this question. Looking to history is the best resource for this question. Historically, revolutions (because that's what we are really talking about) occur when the populace's concerns are not being addressed AND the status quo, whatever that is, is the scapegoat. Wars for independence are fought because there is a perception of the rebels being taken advantage of by the empire. The American Civil war was fought because the Confederate States felt that the Federal government was not serving the will of the populace in those states. Historically, the question of resources is somewhat less important because where there is a will, there is a way. France supported America in the American Revolution, the United States has provided material support for many revolutions and resistance movements throughout the world. This scenario would play out in the same manner. Interested parties would provide support either openly or clandestinely because they feel that they have something to gain should the rebellion succeed. Blockade runners have supplied rebellions as long as there have been sieges and every other world power has both the means and the motive to weaken the U.S. Russia and China would be air dropping supplies in a heartbeat and would claim that it was purely humanitarian, and the Federal government would have to contend with the court of public opinion in any conflict. The more heavy handed the response, the greater the risk of drumming up support for the insurgency. We can see that happening RIGHT NOW in the middle east. Others have argued that a single state could not stand against the might of the U.S. Military, but remember that this is not a pitched battle with a small militia or even the National Guard fighting on a battlefield. This would be an insurgency and you would have American soldiers being given orders to kill their own countrymen against men and women fighting to protect their own homes. Remember that the entire active duty military is less than 1.5 million troops. That is less than the population of Iowa. I think it is also likely that individuals that did not support secession would have already left ahead of the actual declaration and believers in the cause would flock to the state in support, and so you would have a greater percentage of the actual population ready to fight than would exist in the rest of the country. In short, the state would be engaged in Total War while the rest of the U.S. would be divided between supporters and Federalists with a significant portion not really caring because it doesn't directly affect them. There is nothing that would really be a barrier to secession today other than political will within the population. The States most likely to secede would be the States that are most at odds with the federal government. Basically all of the American west and bordered by California, Oregon, and Washington. Those States on the Pacific coast could go either way, or possibly you could even see a split between northern and southern California with half remaining loyalists and the other half joining the rebellion. Texas is an obvious choice because they have the resources, the coastline, the population... Texas could be its own country tomorrow and there would be literally nothing that anyone could do. The east coast is too interconnected now for any one state to secede, but the "south" still has a population that believes that "the south will rise again" and I think of any one state went, the rest would be likely as not to follow. Texas is the only individual state that I think is really "likely" to secede, but as Washington becomes more and more disconnected from the wants and needs of the states, the question really becomes about which States interests remain aligned with the federal governments and which are not. Montana, Wyoming, Colorado, Arizona, Oregon, Alabama, Georgia and I'm sure there are others increasingly have ways of life that are at odds with our national leadership. Our forefathers saw this eventuality and created a system of representative government that was designed to give the States a way to protect their interests, but our two party system has undermined those protections and set us on a course that virtually guarantees that eventually some part of our country will no longer trust that their voice is heard, and secession or revolution will be the only avenue that remains. [Answer] Perhaps the question shouldn't be which states are most likely to rebel (Texas, obvs). But rather how would the USA fragment if the federal government broke up somehow? It's not going to be, what state goes it alone; but how do the rest of them decide to align after the fall? Because presumably if the conditions arise where it is realistic for one state to leave, it'll be likely that most will. In this case, you may like to consider how at present the USA is divided culturally; this is an interesting map. [](https://i.stack.imgur.com/veuWk.jpg) <https://www.washingtonpost.com/blogs/govbeat/wp/2013/11/08/which-of-the-11-american-nations-do-you-live-in/> [Answer] My list is 1. California, with its huge secession movements. 2. Texas, their people wanted to be a nation before it joined the U.S. back in the 1800's. 3. Arizona that the region is way far too different from the US. 4. Alaska same reason for Cali but less severe. [Answer] I would first go with Texas, if it had to do with an economic rationale for secession. They are basically the only state with their own energy resources; they could economically fend for themselves and would be most likely to rebel against an intolerable exploitation from the outside. However, the OP said it was due to a privacy rights issue, then you probably first see secession in the same states that legalized marijuana in the face of the federal government. Namely Alaska, Washington, Oregon, and Colorado. But because of the geographical disconnect the pattern would probably go: Washington and Oregon at about the same time, followed very shortly by a block of Northern California, then Idaho and Colorado. Montana would most likely follow suit to not have mess on their Western border to make the "Northwest Block". Alaska would most likely join sometime in the path. After that...it gets fuzzy. Update: It does make an interesting Eastern Front for any hostilities. [Answer] I think who would be most likely to secede depends largely on who is in power in the Federal government. To put it simply, if liberals are in charge, the conservative states would be more likely to secede, and vice versa. As the U.S. government has been trending liberal since the 1990s, I'd say a scenario where the conservative states rebel is more likely. But that could change overnight if, say, an extreme right-winger was elected president. A closely related question is what would happen if one or more states did try to secede today. Expectations about what would happen would heavily influence who would be willing to try it. Would the Feds immediately send the military in with guns blazing? I doubt it. I expect there'd be a period of negotiations before any violence. If the Feds thought they could send in the FBI or marshals and arrest the governor or other leaders of the secession movement, they might try that. Would local police and National Guard troops back the secessionists or would they side with the Feds? Bear in mind that local police today are being increasingly "militarized", with military-class weapons, including armored vehicles. If the police and National Guard backed the secessionists, would the military be willing to fight them? For that matter, what would the military do? If we were talking about half the country seceding a la the Civil War, then half the military might come from seceding states, including the leaders. Depending on the reasons for the secession, many in the military might be sympathetic. [Answer] Let's pretend the US Government is going to pass a law that will ban guns. By just signing that bill, the state of Montana will immediately leave the Union. Their state Constitution requires guns to be legal for Montana to stay in the Union. Texas would secede (no explanation required). Also, the states that allow a citizen to carry firearms with no permit (it's called Constitutional Carry). I also know that all other southern states will leave the what is left of the US Government to rot after such a decision. [Answer] Well, California is currently floating a secession referendum as part of it's election tantrum. The only way that would ever happen is if someone was able to replace the funds the federal government pours into the state. Though given the current political climate in the state (brought on by oxygen deprivation from constant hyperventilation), the referendum probably reads something like: We are seceding but the US still has to give us our share of the federal funds. [Answer] I'm going to have to say that it will definitely be a western state. With western state's solid history of united rebellion, it wouldn't be surprising. Western ranchers would start it, then many conservative fellows would follow up and support. This is evident in the 'Sagebrush Rebellion', the Bundy Ranch incident, and the recent Malheur National Refuge incident. Also, when Claude Dallas killed a wildlife warden he was hidden by local ranchers and miners in the area. It seems that these people are willing to unite and protect each other. I know for sure that Idaho and Montana have highly independent anti-government sentiment. Most western states do, Arizona, Nevada (Nevada only votes blue because the majority of the population is in Las Vegas, these people are California transplants), Utah, Colorado and Wyoming. These ranchers and miners feel abused by federal power in a lot of situations. ]

[Question] [ I've looked around here a bit, but I haven't managed to find a post that really answers my question (though if there is one, please let me know). I'm trying to write a story where the two main characters decide to stow away with some travellers who come through their village annually, and I want the travellers to realise that these kids are there when it's too late to turn around and take them back, so the travellers have no choice but to go about their usual annual route before dropping the kids back at the same time next year. I would like this to be due to some geographical or even season-related reasons and to have the region where the village is located only easily accessible perhaps two or three times a year. So I'm not looking for something like the tides making a certain island only accessible once a day, since that's far too frequent (though it is of course fine if it's a tidal event that somehow only happens a few times a year). Let's also assume that the years and seasons are basically the same as here on Earth. So, is this possible? And if so, what kind of environment would make it possible for this region to only be easily accessible two or three times a year? (I don't mind if the amount of times the region is accessible in a year is more than two or three, but I'd definitely like it to be **no more than four or five**, if possible.) I would also appreciate it if an answer for both *how long* the region remains accessible (preferably a week or so), and how long it takes for whatever occurs to make the region inaccessible again is given, too. **As a note:** It doesn't have to be *completely* inaccessible for the other parts of the year. Just difficult enough that a band of travellers who are rather slow moving with some carriages and heavy luggage don't think it's worth trying to enter the region outside of those few times a year. Thanks in advance for any answers given :) **EDIT AFTER CHOOSING AN ANSWER:** Thank you everyone who has answered this so far! I have waited about a day and chosen [Zxyrra's answer](https://worldbuilding.stackexchange.com/a/58738/15583) as the best because it's got the most up-votes and for the most part I think it's one of the most useful. Although, there are a number of answers that are similar and I'm thankful to everyone who gave suggestions :) [Answer] **There are many ways to change access to an area throughout the year:** ⚖ ***Seasonal Extremes***: Typically, the further from a major body of water a location is, the hotter the summers are and the colder the winters are. Proximity to a lot of water sort of averages the seasons' temperatures together as long as you are not close to a pole or the equator. If you have a location in the center of a massive continent that is neither close to the pole or close to the equator, then the summer months would make travel extremely hot - up to deadly, desert temperatures. In the winter months, the snow, ice, and cold would also be extreme, leaving a few weeks in the spring and a few weeks in the autumn to travel to and away from this location. ❄ ***Ice Needed***: You could make your location similar to an island in the Bering Sea. During the summer months, the sea is liquid. Maybe in your world, it is full of creatures that prevent sailing, or reliable ships that cross this area are expensive. In the winter, the entire Strait freezes, at which point your characters could buy metal spikes for their wagon, or hire a dog team, to cross the new bridge of sea ice to the desired island or northern continent. This would leave several months for travel, but for the majority of the year this route would not work. ☂ ***Water Needed:*** The opposite of the above. If an area up north is frozen for much of the year, but the ice isn't safe to cross, maybe it thaws for several weeks allowing passage. ☽ ***King Tide***: About once yearly, the alignment of the sun, moon, and Earth produces what's known as a king tide - in which some areas see extremely high tides while others see extremely low. You could use either the high tide or the low tide during this event to access a location: Low tide - imagine the only route to your town is through the mountains, and the only route through these mountains is a natural pass that looks like [this](https://images.travelpod.com/users/terry_dianne/1.1253126036.the-natural-bridge-natural-bridge-station-va.jpg). Now, imagine that this borders the ocean, and that the pass is actually a small saltwater inlet. During all other times of the year, this arch is completely submerged, but, when your planet, moon, and star align perfectly, people use the pass for travel and commerce for several hours. A stretch, yes, but unique. High tide - finally, your location could be on an island with extremely high cliffs such as [these](http://img.dare.co.uk/wp/vestmanna-cliffs-faroe-islands.jpg) if not much, much taller. Only once during the year, when the planet, moon, and star align, does the tide rise up and allow ships to do business for a few hours. [Answer] **Winter** Harsh winters came to mind first being from North America. The best part about winter is that it can either enable or prevent travel to a certain location. A. If your village is separated from the outside world by a mountain pass big enough to have snow caps in the summer, you can bet anything it would be suicide to attempt traversing during the winter months (see [Donner Pass & the Donner Party](https://en.wikipedia.org/wiki/Donner_Pass#Weather)). B. Areas up near the arctic are *only* available to modern trucks when the sea water, large rivers, lakes, and just the ground itself freeze solid, forming ice roads. Obviously You could raft or kayak across but if you have enough supplies or people, the expanse is large enough or the terrain perforated enough, then you would need a caravan and the path to be frozen. **Deserts** If you need to cross a vast expanse of desert, you'd best do it if you know you can carry enough water or get some along the way. Desert areas can have ephemeral rivers, which only flow when there are significant rains. You have a ton of flexiblity here. There are examples in Australia that only flow for a week when they get hit by just the right rogue monsoon, which may take years or decades to happen. You can also have semi-predictable wet and dry seasons. Others might flow seasonsly and for a bit longer as snow melts from near by mountains during the spring months. [Answer] **Disease.** Specifically insect-borne disease. The rainy season arrives, the lowland swamps have a population explosion of mosquitoes, midges, tsetse flies or the equivalent. These insects carry some nasty disease to which humans (or their domestic animals) are susceptible. Fatal or just debilitating is up to you. Maybe not fatal but with a side effect such as horrible smallpox type scarring, or deafness/blindness or impotence. So everyone just avoids the lowlands at 'fever times'. You can have more than one rainy season a year - for instance, Kenya has 'long rains' and 'short rains'[Kenya climate](https://www.expertafrica.com/kenya/info/kenya-weather-and-climate). The travellers would also know that just as they are heading south to avoid the lowland swamps, the kids' community will be heading north to also put some distance between them and the insects. [Answer] There is a small town Verhneimbatsk - [You can see it on the map](https://yandex.ru/maps/-/CZgjr00b). I think, since 17 century this town was trading outposts - natives (called kets) were trading furs with Russian merchants from city of Krasnoyarsk. There are only 3 reliable ways to get to this town - 1. by air, postal helicopter 2 times per week, 2. by Yenisei river, using boats from middle of May to middle of October. 3. by Yenisei river, using snowmobile or sledges with dogs from the end of October to end to April (but using dog sledges can be quite dangerous and hard for trade). And, probably not very reliable way, use really big team of lumberjacks to make road through taiga forest. On the second half of october the winter starts, and river is covered in ice in few days. So, the situation can be like this (i assume it is pre XX century level of tech) - in the middle of October, traders came by boat to this city, exchange wares for furs, than they sail in hurry to the next town, because river is covering in ice. All travelers were busy by setting sails, using sticks and paddles to repel ice from boat. And, in this hurry, they were unable to see, that few children managed to hide between sacks of goods. UPD: also it is worth notice, that end of September is usually very rainy, and river surface is raised to ~ 1 meter. Maybe there is a lot of stones on the bottom of the river, and they can break the boat. And, with elevated river surface after rains, sailing is more save. UPD2. Answer for @Yakk's question: The weather can be quite unstable - the ice can start appearing on every day from 5th to 20th of October, and usually it takes few days for river to be covered in ice. The mecrhants was not aware of the exact departure time. By careful weather observation, everyone knows, that if there was 3 days in a row with strong wind from North, than ice will start appearing, but if there was only 2 days in row - no ice. And merchants used this knowledge to plan departure. Why i think it was acceptable risk - The current speed is about 8km/hour. And merchants were travelling down the stream. So, if they were acting properly, they can easily travel more than 300 km until river is covered in ice, it is enough. And, in 300 km there can be a major town, where they can trade goods too and pass the winter. [Answer] I really like the animals idea, and in a similar vein the passage of an area could be restricted by **plants**. There are [a myriad of real-world poisonous plants](https://en.wikipedia.org/wiki/List_of_poisonous_plants#Other_poisonous_plants) that can cause irritation, pain or even death just by humans coming into contact with their leaves. It would not be a stretch to believe that one of these plants blooms at certain times of the year, perhaps within a forest that can only be crossed during winter/autumn when all of the leaves have died. Then when spring comes around, the forest becomes inaccessible again. Of course, having a forest that makes a village *entirely* inaccessible for half of the year is unlikely, so perhaps it just makes it extremely inconvenient for the two villagers to return home. Another reason not to return could be due to **economics**. If the travelers cannot afford to travel back to the village, as they don't have enough food to account for the extra time spent heading back, or have perishable goods to trade at their destination, they may decide that it would cost more to take the villagers back than it would to let the two stowaways stay with them. Just because the travelers can physically head back to the village, doesn't mean they would be willing to. If the only requirement is that the travelers cannot just send them back on their own, as they would refuse to escort them back, then this allows a greater number of reasons for them being unable to travel back alone until the larger group returns to the village. This could be anything from highwaymen that target smaller groups of people to animals that only ignore the larger groups of humans. [Answer] ### Spring Floods As the snow in the mountains and hills melts, small creeks become raging rivers. Sure, one could camp out until the waters calm down, but the caravan might not have enough food to wait that long. ### Water Hole Capacity In a dry area, the caravan uses water holes which take some time to replenish after a *large* group went through and took all the water. So a caravan can never turn back, only go forward. (Of course that would mean two different caravans would be disaster for both.) [Answer] As Zxyrra stated in [their answer](https://worldbuilding.stackexchange.com/a/58738/15583), there are many ways to build an inaccessible area. Here's just another idea I haven't seen mentioned yet. **Animals** You could have your piece of land be inhabited by dangerous predators. Navigating through the area without encountering these predators may be possible but will become more difficult the larger the traveling group, especially if also traveling with wagons. In winter, these creatures go into hibernation, allowing for a safe passage. [Answer] ## Mountain pass It's reasonable to have places only reachable through a single mountain pass. It's reasonable for that pass to be traversable only part of the year. For a real life example, maybe it's illustrative to look at the remote Georgian region of Tusheti, which is still currently accessible only for part of the year unless you use a helicopter - there's a single road leading to it, it leads over a 2900m / 9300ft pass, and the road is not considered traversable in winter. From the pictures e.g. <http://unusualplaces.org/one-of-the-most-treacherous-roads-in-georgia-the-road-to-tusheti/> it seems rather obvious that if it was snowed over, waiting a few months would seem a reasonable option. [Answer] Either the land is surrounded by water and swamp for much of the year but it dries out enough to cross in summer, or it's surrounded by water *all* year but it freezes over enough to cross in winter. Take your pick. [Answer] The 'Pitch Black' story line comes to mind here - > > A total eclipse allows creatures dwelling underground to surface and kill things, and soon as the sun comes up, they go back underground. You may be able to say the equator + surrounding x miles is the only section of the world that experiences the eclipse, making that region completely impassable for all but the baldest of muscle men. EDIT: They don't come out at night because there are multiple suns, so it never gets completely dark. > > > [Answer] The Great Rann of Kutch in Gujarat, India is a lake that is dry during summer and flooded during monsoon. More info here -> <http://www.hornpleaseok.net/2014/08/trip-to-kutch-gujarat-dholavira-rann-of.html> ``` -> http://www.travelclassics.com/library/india_rann.shtml ``` [Answer] An island with temporary ice sheet in winter. You can access it for a few weeks in summer, after which ice forms on the sea, making it very difficult to board. In autumn, any boat would risk being caught in the ice, or sunk by an iceberg. In winter, the reaching the island would mean boarding on the ice, crossing a long distance on ice in blizzards, and in spring the melting would make the icebergs and the instability of the ice even more dangerous. Similar to how some stations (like Dumont D'Urville) in Antarctica are difficult to reach outside of a few months in the warmer season. [Answer] 1) The place is kind of like bermuda triangle which opens up/becomes navigable at the time of the "green flash" *pirate lore*. 2)Probably after an geomagnetic storm which makes it possible for aeroplanes to pass with least interference. 3) place surrounded by mountains filled with smog. Uncharted territory. It makes it impossible to for planes to pass. You have to rely on the migrating birds for guidance. (hmm...Pandora-ish) 4) A no-fly zone. Riparian states that fighting over a water source. So, Transportation is possible only when the source is dried up. 5) Mythological Areas: Certain areas are made off-limits certain times of the year as they would be visited by certain deities. (Fishing is banned at my place for few months to facilitate the fishes to breed. also to balance out excessive fishing.) [Answer] **Frame Challenge** > > I'm trying to write a story where the two main characters decide to stow away with some travelers who come through their village annually, and I want the travelers to realize that these kids are there when it's too late to turn around and take them back, so the travelers have no choice but to go about their usual annual route before dropping the kids back at the same time next year. > > > Why is it the travelers' responsibility to escort those kids back? If the kids manage to stay hidden for a couple days, I would be surprised to see the travelers going out of their way to get them back and get going again. Note that for each day the kids are hidden, the travelers would have to add two days to their travel, which might derail many plans and arrangements made. Imagine, for example, that they have to catch a weekly or bi-weekly ferry across a great lake: be one day late, and you have lost a full week (or two). And this just compounds. Since your group of travelers come every year, I expect that they have a rather set journey plan, and delaying it might significantly affect them. There may be events along their road that they are counting on (fairs, ...) and missing them would cost them money, maybe a lot of money. On the other hand, keeping the kids and having them work for their food does not incur any delay, and is still morally "fair". --- Note: There is also a "simple" way to increase the delay (and cost). If the kids are discovered rather quickly, but argue that they are going to the next town over to their uncle's house, the travelers might find it more convenient to just follow on. Of course, once they arrive in the next town after a few days and there's no uncle to be seen, it now is very expensive to get back to the village... [Answer] I see only a handful reasons which are all bound to the classical elements: Earth, wind and fire; water; plus radiation, as a modern "element". Others have given more detailed ideas for some of them; in general though, the reasons for the "elements" to shift seasonally are bound to celestial movements, either of the planet in question, or of near-by celestial bodies like a twin planet or a moon. A double-star could be interesting. Radiation could come from a star emitting hard gamma which is most of the time shielded by another body. The only other seasonal shift is geological, like a geyser or volcano with a long-time stable period of a few months; possibly in connection with tidal forces of a close body destabilizing the planet's crust. [Answer] An easy solution to your dilemma would be a one-way-road. A stretch of land that is only passable in one direction. A wide fast flowing river surrounded by impenetrable forest would be an obvious candidate for this scenario. In that case your travellers would travel in a circle and part of that circle would be the river: A very fast and convenient way to travel … but only in one direction. Travelling on this river could easily be more than ten times faster than hiking back trough the (dangerous) woods. So the kids would only have to stay hidden for a few days, which is probably more realistic than waiting for the seasons to change. [Answer] An underground fire in a coal seam that contains heavy metals making the smoke that rises from it toxic. Such fires have been known to burn for centuries, like in abandoned coal mines. The valleys near the coal deposit collect the smoke, which is heavier than air. During the rainy season, runoff dampens the fire and reduces the output of smoke, making the way passable. Occasional droughts make the area inaccessible for four to five years at a time. [Answer] They travelled by ice boat. For hundreds of years ice boats were the fastest way to travel, however they only work when there is ice with little to no snow. In the past large cargo ice boats have been built and used to ferry cargo. I could see the kids being very interested in stowing away on one for the experience. [Answer] I was primarily going to answer as Zxryya did, so I am torn about answering at all with just the leftovers, but here you go: If you travel by sea, then the state of the sea matters. A treacherous region of the sea because of rocks or reefs can become completely safe when tide is high. This isn't *just* a daily cycle, as a few others mentioned, and tide is not the only option for raising the local water level. When the monsoons come, they fill the cave pass. When the summer comes, the melting snow fills the creeks and rivers with icy water. If that melting ice involves large chunks falling and diverting to various channels unpredictably, that's even weirder, since some areas might rise and lower. You also have storms: There are places where the storms are rather predictable. You might not know the specific dates that a storm will boil up, but during certain seasons, you can know to expect one within a window. If the trip required is longer than that window, people might know better. As simple as a steady wind is, it can make navigation tricky. Imagine if the wind is harsh but there are dangerous rocks sticking up out of the sea all over the place. If the wind varies only a few MPH and angle, it still makes that treacherous. If it's less predictable than that, all you need is a narrow straight made up of tricky rocks to avoid, and you've got a very good reason not to go that way. So, there are some more ways that things can become semi-prdictably inaccessible and linked to almost any schedule that you want. (What I mean by this is that you can mix and match effects to make the trip accessible when you want it, pretty much. e.g. The passage is a cave up a mountain side. It's a rather risky climb, what with the local wildlife like goats and wildcats, at the end of the dry season. At the beginning, well, it's underwater. You have to wait for the lake to dry a bit after the rains to open enough to get through. For about a week, once or twice a year, the passage is filled with enough water that shallow boats can simply sail in with cargo. This is their trade time. e.g.2 The opening to the passage is underwater all year round, but the passage itself is mostly above sea level. The ice on that shelf does this strange thing where it peels back for a few days, revealing the passage. Locals rush out and harvest the various sea creatures during that time. [Answer] # Radiation There are a few ways in which you could use this. In one case, you could have a derelict nuclear power plant spewing out radioactive waste. For most of the year, the leakage is confined to the immediate area around the plant, but certain seasonal extremes could make for difficult traversal alone, not to mention a storm of radiation at your face. These weather disruptions could occur for weeks or months at a time. You could also keep the planet as it is and make the star highly radioactive with relatively predictable solar flares which scorch every living thing and piece of electronic equipment on the surface, requiring residents or travelers to bunker down during "radiation season." The frequency for these solar flares could be a quick succession lasting less than a day but anything exposed during that timeframe has no chance of survival. [Answer] The village is mostly surrounded by very steep mountains. One side of the village is open to outside travel. The ground beneath that opening is filled with natural gas that leaks out and makes the villagers sick and short of breath. They decided to burn the gas to prevent these issues. A giant fire rages almost year round, blocking entry/exit. A very small creek runs from the mountains into the village. They damn up the water and use it for their water needs. During the winter they get excess water and after a year of collection the damn is now full. This is the one time when they let the water flood out and put out the fire so that people can come and go. Once everyone has gone through they start the fire again as villagers start getting sick from the gas. It takes a year of collecting water in the damn before they have enough to put the fire out again. For a reality check on this idea see [Burning fire pit](http://www.smithsonianmag.com/travel/giant-hole-ground-has-been-fire-more-40-years-180951247/?no-ist) [Answer] Water levels, but a very different answer than above: The area is ringed with mountains sufficient to block normal travel. The only reason there is anyone living there is that there is a river that flows through the area, on both ends it flows through caves. In periods of high flow you run out of ceiling. In periods of low flow your raft runs aground. Note that the safe flow rate for the two caves is different, this gives one window in which you can enter and one in which you can leave and they do not overlap. Note that properly packaged cargo can be shipped during periods of high flow--pack it to take a beating and drop your container in the river, it's fished out by nets on the other side. The water flow over the ages has worn away any spots that would cause them to hang up. [Answer] You could just take a magic approach if a fantasy setting. The town only appears at x location for x amount of time before disappearing to a new location or back to its own dimension. There is a movie called "Krull" where the castle/fortress they needed to reach was only going to be at a specific location for a short time. Or town is stationary, but protected by a magic veil/curtain/wall that is only passable under specific conditions. (a la "Mists of Avalon") Or the region could be on a floating island that is only in range for a certain amount of time before it floats out of range again. Maybe it circumnavigates the world/floats with the ocean currents. [Answer] Two things come to mind for me that I didn't see mentioned: * First, **fire**, a massive forest fire would certainly cut off a return path through a wooded area, and without modern fire fighting equipment they can burn for several months. * The second is completely out of the loop from natural reasons to be cut off, but what about **some sort of conflict**: a war, a military action, an invasion. This wouldn't have to have anything to do with your current story, but it could make a nice sub story while providing the tool to muck up a return trip. ]

[Question] [ [Somewhat, not really related](https://worldbuilding.stackexchange.com/questions/6413/what-happens-if-everything-stops). In my young adult story, the main character has a mechanism that allows her to pause time, and do things while everything is frozen. I have no problem 'magic'ing the power of this machine. But I would like to explain in more depth the effects of this mechanism. If she turns on a light, she's drawing electricity which is coming from a coal power plant, no? A car frozen going downhill is stationary, but if she rolls a ball across the room it continues to go. Why does the sun not stop warming her? Etcetera. She has stopped universal physics (except for herself), and yet physics still works. I don't want to leave this explanation out, but I don't know how to explain it. **What are the boundaries to things that stop?** I'd still like her to be able to get up to mischief. EDIT: This is intentionally NOT a hard-science tag. This is a worldbuilding request for the best way to describe the strongest boundary where physics must give way to 'magic'. [Answer] *None of the below has any scientific basis*, but it can potentially be made compatible with a (mostly) scientific fictional world, and a magical world that interacts with it within limits. The character doesn't *stop* time, but shifts to a place *outside* of the universe's time, in a kind of shadow world to the real one. A different dimension of time flows for the character in this place, allowing them to act. In this place they can move freely between shadow places in the real world, but not forward or backwards in time with respect to it. The character needs to have a way to perceive objects. The shadow world may have it's own equivalent of photons that interact (without transferring energy) with the real world. This could look very different to vision in the real world if you wished to get descriptive. To have any impact in the real world, the character needs to be able to interact with objects. Whatever mechanism transfers the character allows them to select objects - or parts of objects - to transfer into the shadow world where they can be moved or manipulated and then placed back into the real world (the fact that this might *immediately* displace some air could lead to a tell-tale "pop" sound). With this mechanism there is no particular reason why any real-world objects are tangible/solid for the character - i.e. they could fly, move through objects, etc. But they may want to limit what they do in that regard if they are not fully in control of when (in the sense of their activity time used whilst everything else is frozen) they return to the real world. So it would be a huge risk of injury or death to move through solid objects, or even liquid if it could not be displaced. *All this setup gives you an answer to the original question:* > > *In this variant, the character cannot make objects draw power, or roll a ball along the ground. They can merely teleport things around > by manipulating them into place one at a time.* > > > You can add more limits to how much effect this has by making staying in the shadow world take effort or amount of action allowed be unpredictable. Likewise manipulating an object could cost effort or total shadow-world time depending on its mass. A very simple premise could be that the character cannot breathe, there is no air in the shadow world, and all the real world's air is frozen in place of course, so entering the time freeze is a bit like free diving. In terms of story effect and how much risk such a character is ever exposed to, it might be wise to add some constraints to a time-stop effect, otherwise it can become a "solve anything" ability which drains away tension from a story. [Answer] Um...everything? Time freeze is unfortunately not logically consistent with reality. Think about it this way: If you freeze time you are stopping things from **changing**. **Time and change are fundamentally linked.** If nothing changes does time pass? Logically, maybe it does, but the basis of time is change and vise versa. **In short there is no way to explain the system you mention within the bounds of physics etc.** If air molecules don't move can the unfrozen person pass though them? If energy is not moving through the air (sunlight) would the unfrozen person be able to see, or hear? There is no method beyond hand-waving or magic (fancy hand-waving) that will allow for such a scenario to occur. --- **In response to the bounty posting:** If you stop time and yet want things to happen, \*for anything to happen physics must immediately give way to magic. The only thing you could do without violating that is to think hard (while suffocating). **In short the boundary you are asking for is any action your protagonist takes.** There is no subset of actions that would be allowable under physics. You can't stop time AND do stuff without magic. With the exception of thinking really hard for however long you can hold your breath. You kind of just have to give in and say: *Magic* (jazz hands will spice it up) [Answer] **Time is relative.** Instead of freezing all other time, just have your character speed up her own. From her perspective all other things will have effectively stopped. This concept is explored in Treason by Orson Scott Card. Obviously, Card is a master of young adult novels and explaining how things work. He also explored this (ad nauseam, in my opinion) in his series Pathfinder. In Treason, when the character speeds up his own time flow he must be careful not to touch other people, because from their perspective they would be struck at very high speed and might suffer broken bones or bruising. In Pathfinder, instead of changing the flow of time, the characters skip in time. I only recall them speeding up their time by skipping forward. But I imagine a similar effect could be used for slowing time. She might skip backward in time 0.999 seconds per second to perceive time as being slowed. This skipping method is probably the way to go, it's like pulse width modulated time. It might be easy to describe it as how LED lights are dimmed, it's not through getting less bright, but really is achieved by being just as bright for shorter periods of time. If your character is walking around while jumping back in time for an appreciable percentage of the time she is moving forward in time (at the normal rate) then time will appear to slow down. It's important that the [time travel paradigm](https://worldbuilding.stackexchange.com/q/20371/3202) is one where she can not meet her past self. [Answer] Try not having sharp edges between paused and not. That sharp edge creates all sorts of funny weird behaviors and demands all sorts of handwaving. Instead, treat it as a speed up effect which emanates from the caster. Things that are closer to the caster move faster than things that are further away. This avoids funny issues like "does my clothing move with me when time is paused?" Since the clothing is close to you, it will move almost freely with you. This also opens up the door for some hard-magic style thinking regarding the shape of the field. A novice might be able to create a spherical field, so that those who are close to them move fast, and far away things move slow. A skilled user might be able to shape the field to conform more to their body, so that they can move through tight fits between two frozen individuals. Indeed you could go so far as to solve the question of what happen if someone pulls the cord on a lamp. If a novice does it, the lamp may be "on" but not light up, because the electrons in the wire are not moving fast enough. A professional may be able to shape the field to include enough of the electrical system to allow the lamp to light up. This might require some extreme motion, such as shaping the field to include all of the wires all the way up to the power station, but somewhere along the way you should be able to start handwaving it because someone with that much control would be very special and do all sorts of really neat things. [Answer] Alternative model which might achieve what you are trying to do with less trouble: Time doesn't stop, she just becomes extremely fast. From her point of view it appears as if time became so slow that most things just don't appear to move at all. But from the point of view of the rest of the world, she became amazingly fast. The problem with that is that she also became amazingly strong. Let's say the time dilation factor is 1:100. When she throws a rock with 10 m/s, it actually moves with 1000 m/s. It will have enough kinetic energy to pierce through a concrete wall. It will seem to her as if the whole world is made of wet tissue paper. She will have to be very careful to not cause any damage. Even the air she displaces by walking around and breathing might cause dangerously strong storm gusts. [Answer] What if the universe only functions when watched by an intelligent observer? What if changes in state (or motion) are a function of those observer's perception? The Schrödinger's cat thought experiment seems to imply that that might actually be the case. And if it is, how would we ever know? We cannot know a thing until we look at the thing, so if our looking influences the results, we are skewing the results every time we inspect them. Now in this perception dependent universe, all a person would have to do to stop time, is diminish the authority of everyone-else's perception to a level beneath the intellectual threshold which insights motion. Once this is somehow done, your unstopped/undiminished heroine can enjoy the godlike power of being the only animating force in the universe. What she sees or interacts with, functions normally; Balls that she kicks, roll while she watches them. Sunshine strikes her face because she believes it should. Air molecules move out of her way, because not moving would defy her expectations. Meanwhile, all around her, the rest of the universe remain static and unchanging, just as all the gold-watch stories which she's read, suggest that it should. Other people are a bit of a challenge to this answer. The classic time-stop scenario has other people standing around like Mannequins. But if motion in the universe is driven by your heroine's perceptions and expectations, then the people she sees should re-animate as she looks at them. So what if her gaze does reanimates other people's bodies, but not their minds, not their motivating source. If she looks at someone who was falling, they would continue to fall. But if prior to the time-freeze, she hadn't seen them falling, they would just stay where they were, with no new motion starting from within them. Similarly, non-falling people would be technically animate, but un-moving because their minds, which the heroine cannot understand or predict, remain frozen with time. They might even have a heartbeat and blood pressure, but no will of their own. This opens up some interesting plot opportunities involving intimacy and love. If she looks deeply into a frozen person's eyes, she might be able to see their souls like a frozen fire; and in seeing them in this way, come to understand them, at least well enough to reanimate the minds. Such people would become alive in the frozen world, at least until she looks away. Similarly, people, whom the heroine already knows closely and/or loves, might be immune to the time-freeze, since her knowledge of them is a permanent part of her perception and understanding of the world. She might find that she is not as alone in this static reality, as the stories suggest that she should be. -- this is a heavily edited version of my original answer which included some scientific assertions which didn't survive peer-review. -- [Answer] A simple way to explain how she is free to move about while everything else is seemingly frozen, is the conduction of time (like conduction of heat). Time moves rather slowly for everything else, with the pace sped up by absorbing time from the protagonist (like heat transferring from one object in contact with another). The air around her has so little mass, it immediately gets enough time to move normally (though the farther away from her it goes, the more diffuse time gets, so thicker air seems to be). Rooms would get hot and stuffy as the air in it doesn't ventilate much, so suffocation and body-heat dissipation might become worries if she doesn't keep moving about (so don't sleep in this state). This explains why the things she is wearing are not immovable barriers as they have been in contact with her long enough to equalize time with her. Things she picks up might seem slightly stuck and resistant to moving at first (like a rusty hinge), but start to shift more as she is in contact with it. Larger objects like doors might be very difficult to move, as so much mass would take a while to get up to a practical movement speed. She could probably walk over a swimming pool (run at least) as it takes a while to get moving (just as it would take a while to heat it up), but a cup full would be easy enough to drink (though perhaps with the consistency of syrup when she first picks it up). While she is holding a ball, it keeps getting enough time to keep it reasonably normal behavior, but if she rolls it away from her, time will dissipate from it, slowing it more and more the longer it has been out of her hands. She can breathe, she can eat and drink, she can move about completely normally, and even manipulate objects (though larger objects seem exceptionally heavy), but otherwise things around her seem frozen (even though they are just moving too slow for it to be visible to her). If she isn't looking at something fast-moving, she might get surprised to see it having changed position over time if she wasn't aware that everything wasn't completely stopped. The world may seem a tiny bit more dim, but the apparently slower speed of light is still so fast that it isn't significant. She would need to be very careful about touching anything living - having where she touched running at a different pace as the rest of it could cause serious damage. Likewise complicated electronics might pose an issue - lights would work (though even an incandescent bulb would take a little warmup time), but anything more would not (minor allowance for hand-held devices). [Answer] One possible and rather fun concept is to play a little bit with the concept of 'time' allowing interactions the character hasn't had yet to unfold in the future, propagating the fact that they must have happened back to the present.. That's a very unclear sentence. If we consider an example using light: When time stops, So does the light, right? This means our heroine is unable to see. But what if the light that's going to hit the heroine eventually 'knows' this ahead of time, and keeps moving anyway? That's not inconsistent with some theories of how photons operate. But of course: there was something that produced this light, wasn't there? Fusion in the sun needs to make the light (I know it's not technically accurate, but shush), so that can't stop either. Essentially the fusion process knows ahead of time that it's going to do something that will materially affect the heroine, so time restarts for it at just the right time (relative to the heroine) to push out a burst of energy in the right direction to bounce off a motionless body to hit the heroine's eye. The rest of the light, heat and the heavier elements made by the fusion process remain stuck, however, unless they're needed to kick off another process that eventually affects the heroine. Now, given the way the sun works this eventually leads to most of the sun being 'on', but with any process that doesn't directly affect the heroine paused. When it comes to objects, light switches etc, all the physical processes required 'know' ahead of time that they will be required as part of a causal chain leading back to the heroine. It's like anything that has or will touch her acts as a conduit to deliver 'time' back to all the things that support it. If the heroine rolls a ball, and the ball continuing to roll (not just seeing the ball roll) will have a future effect on the heroine, then the ball keeps rolling. If not, it freezes again. People become a trivial case. Is it the person that had an effect on the heroine, or just the light that bounced off them? If the latter, the person remains frozen. If the former, they have to start moving, and will stop again once they stop changing something about the heroine. This needs handwaving in two places: *1: What defines a future interaction for the heroine?* Luckily: Plot! *2: When time restarts there are going to be a lot of processes out of synch with the rest of the world.* Mostly they won't be noticeable, but lightbulbs will pulse brighter and burn out as all the photons that were never destined to reach the heroine but had to be made anyway start moving again, things that may have heated the protagonist will get hotter or possibly even explode, pretty much anything electrical would suffer horribly, and there will be violent implosions as air the heroine has displaced but hasn't replaced equalises... Ok, maybe it will be noticeable. But if you can handwave away the trail of destruction near the protagonist, you're golden! Even if you can't the chaos can be used as an interesting plot hook. [Answer] Well, off the top of my head I can think of many limitations. For one, you need to allow photons to continue moving. We see because the photons hit our retina, and our optic nerves relay that information to our brains to process. You stop photons, you're now blind. You'll also have to allow other waves like sound waves if you want to hear. In fact, you'd have to put the entire electromagnetic spectrum back into action. You also need to allow atoms to move. If they can't, then your character will freeze to death. If there's no movement in molecules then your character will then be in a close-to-0 degree Kelvin environment and without some hand-waving they can't survive. With some very strange physics and magical hand-waving, you can survive with your influence being the only catalyst for any event in the universe. Air molecules will have to be allowed to move when you create a low pressure environment in your body, allowing you to breathe. That being said, this has to be a very peculiar set of laws of physics. Given the current laws of physics, it's an impossibility. You violate a lot of fundamental constants, like c. If *you* are faster and can observe the universe at a slower rate, that leads to other issues, like your body becoming extremely hot because of your atoms speeding up. [Answer] If this is not hard-science, then an alternative would be that your device has, per se, nothing to do with time stopping, but with **dimensional travelling**. Imagine a 1-dimensional world. Objects in that world can only move forward or backwards. Add a second dimension. In this 2-dimensional world, objects can still move forward or backwards, but now they can also move left and right in the second dimension, **without altering their "first dimension" place in space** In our 3-dimensional world, objects can move forward, backwards, left, right, but also up and down in this third dimension, without altering their position in the other two. Following this idea, you can say that, time being considered by some the 4th dimension, what your device actually does is to allow the wielder move into this "4th dimension", where objects can freely move and interact with everything else in the first 3 dimensions without altering their position in the fouth one. This way she can also "take" things into the 4th dimension and move them there without altering their "position" in time. She can still see and breathe as air and light particles/waves move to her dimension when she enters in contact with them; similarly, most physics still work the same, althought forces e.g. gravity could be a little harder to explain, as this logic could/should allow the wielder to "move into air" while she's in the 4th dimension. Yet I think there could be a way to explain this if necessary, or be left undetailed if not. [Answer] The main thing is that it's suddenly going to be very dark and you will have no air to breathe. If you extend out the "moving time" field a bit and carry a flashlight (or just your mobile phone) then you could make it work.... although even then pressure is going to start dropping as air molecules leave the area around you and get "stuck" in the frozen time. Equally the flashlight will not be able to illuminate anything outside the edges of the time field. Basically the movie/TV thing of everything standing still while you walk around and see things normally is ignoring a lot of problems with that scenario. [Answer] If you've played the game Braid, there's a ring that slows everything down proportionally to how close it is to the ring. So what if it did the reverse? There was a smooth gradient such that the closer things got to the main character the faster they moved. Then from the main character's point of view, everything slows down that's far away. Now this sort of violates conservation of energy as things coming in would be gaining energy, but things leaving would be losing energy, so on average energy would be conserved, and perhaps deviating from the energy conservation requires effort and thus it is hard to maintain these fields. Indeed it would be harder to maintain the stronger the field was and the more things passing in and out of the field. If the field was centered on the brain you could do things like just make a small focused field to think really fast (till you ran out of oxygen) As for the ball, you could roll it but as it moved away it would slow down and return to normal world velocity so to other people it would appear to roll just as fast as you rolled it. This formulation fixes things like not being able to breath or see, being insanely strong, and allows limited interaction with the world. It also provides limitations so the protagonist isn't godlike. For example flipping on a light switch would turn on the light, but you might have to go over to the light (or expand your field to get it to turn on in a reasonable amount of time. [Answer] The problem with any sort of time stop/extreme time slowdown is that you end up with things needing to move a lot faster than they would normally. If your body is working at the 'normal' rate, then it needs air at the normal rate. But because time is slowed, the *flow* of air in cubic meters per second - increases, and if it's a complete time stop - it becomes infinite. This problem gets worse for things like light - (low) time means no luminous flux, which means it's dark. You could perhaps treat it as if it's a 'field enclosure' - imagine a sort of spacesuit (or forcefield) that creates an isolated pocket, within which everything moves 'normally' - this pocket generates it's own power/food/water/light internally. As long as it doesn't move, then everything is fine. This field 'bubble' that takes care of the little things (like breathing!) and isolates your protagonist from consequences along those lines. It's a very local 'fast time' pocket, with an elastic boundary that serves as a shock absorber for the worst of the 'hit a wall at a million meters-per-second effect'. This would mean a 'running through a swimming pool in a spacesuit' effect caused by the slow time - she's feeling the drag from air moving out of her way slowly, and it's gloomier because there's less light 'per second'. Mobility would feel restricted and slow as a result - but the real benefit would be thinking vs. acting - bullets would move much slower, so could be dodged or batted out the way. The 'bubble' would presumably be time constrained, because of limited resources (and it's 'elasticity' would require energy dissipation eventually). Anyone who's there to observe may see a fast moving blur and 'jet engine' effect of displaced air - you're acting as a high speed piston, so might well create compression down corridors and the like. But even so - your time-acceleration won't be particularly large - but neither does it have to be, given human reaction times - it's entirely possible to pick someone's pocket without them noticing in real time, and magic tricks practically rely on misdirection and illusion. That just becomes that much easier if you can see and react faster, and 'stand behind' someone as you see their head is turning. [Answer] One solution: what happens while world is frozen is not real (yet). It's illusion or simulation or dream of some kind. But any actions taken during that time will happen when time returns to normal. Set ball rolling, and it will start rolling for real. Open a door and it will begin opening for real. It could be some kind of a phantom force, which mimics what was done in the frozen time. Of course simulation/dream would not be perfect, and the longer the frozen time, less accurate the phantom force would be, as real time diverges from it. So undressing someone might be impossible (it might happen in frozen time, but in reality it might end up resembling pulling victims clothes in wrong directions), but pulling their shoelaces open quickly would work. Opening a door or simple latch would work, but using a key to open a lock would most likely have the key missing the keyhole and dropping to floor (the lock might or might not still open, depending on the phantom force acting without the real key). Etc. So how would the frozen time work then, is your actual question. I'd go with, what ever seems "logical" to protagonists brain. So things will be as she believes they would be if it was real time. It's up to you if things actually reflect reality, so she could open a sealed letter and read it, or if she would just see nonsense if he doesn't know what is written. And things would probably be frozen unless she actually touches them an wills them to not be frozen. This would give a lot of freedom to have things appear pseudo-logical in the frozen time, without stretching suspension of belief, when things would then happen realistically (apart from the existence of the supernatural phantom force) in the real time. [Answer] There's a novel by H. G. Wells, called "[The New Accelerator](https://en.wikipedia.org/wiki/The_New_Accelerator)". Mr. Wells thought quite well about the physics of existing in a world where everything around you is "stopped". But it didn't stop time, it speed heroes up to a point when everything around them *seems* to be stopped. It may be a lot more plausible explanation for you to use. [Answer] Since it has been pointed out several times that neither freezing time completely nor moving near the speed of light are survivable scenarios, let’s explore the **Realm of the Mind**. We cannot really explain how and why humans think on a self-aware level, therefore we may as well assume another layer (or level or dimension or sphere) of reality where the mind (and maybe soul) is located and time works differently, because there is no matter. The protagonist had the unique ability to enter this layer consciously and while being there, time either stops or she can even rewind or fast-forward or both. She can do several cool things, most importantly hook into other minds. This kind of *mind reading* doesn’t have to include *thought* reading, but should allow her to read *perception*, so she can see what anyone else is seeing in this very moment. A static snapshot will work for vision and maybe taste, smell and touch, but not so much for sound (incl. spoken or thought language). Hopping from mind to mind she’ll be able to see much of the world at that very instant, but not from a totally free perspective of her own choice (which differentiates it from most stories of out-of-body experiences). After experiencing and enjoying that kind of *omnipresence* for a while, she then might gain the ability to *alter* stuff either by mending perception to influence other people’s actions, by implanting thought commands to more directly control other minds or just by plain old telekinesis. Objects would only move after she has left the Realm of the Mind and returned to her old mind. Later on, “ghosts” that only exist on this layer may be introduced and she may get trapped in foreign minds once in a while. [Answer] Simple answer: Everything--including yourself when you die from a lack of oxygen. If you wear a rebreather you get a bit more time before you die of overheating. (You can't simply wear an oxygen tank as the exhaled air has no place to go, you would quickly be crushed.) In what time you had left you would not be able to see or hear anything, nor could you move. (Moving a time-frozen atom takes infinite energy.) Now, for something that actually might be useful, look at one of *Larry Niven*'s stories whose title eludes me at the moment. It's a murder mystery involving a guy who has a device projecting a time-speeding field (anything in the field operates at a much faster time rate.) While obviously the field itself is handwavium he otherwise tried to do it with hard science--after all, it's a **mystery**, the reader should be able to solve it. I do not recall him addressing the consumption of air in the field, though, I think he missed that one. It's set in his *Known Universe*, early on, one of the Gil the ARM stories. [Answer] It sounds like what you want is to have the magical mechanism suspend the laws of physics. Don't know what you were thinking of in terms of how the character used the device, but I'm picturing something like a remote control with a stop, pause, play, rewind, and fast forward option. On stop, everything stops; the magical mechanism then creates an exception bubble for her, so those laws continue to apply to your character. She can then point her magical mechanism at any random item, and turn on physics for that item/person. If wanting to do this on a macro-scale, have her point the device at a miniature of the universe or planet or kingdom...etc. She could pause an invading army from the north, then spend two weeks leisurely sunbathing on a lush tropical island, before recruiting a bunch of her friends to remove all weapons from the invading army and replace them with salmon. The restart time, and watch the hilarity ensue. Obviously, something this powerful should have limits incorporated into it. Limits of power or range or influence will give you opportunities to create interesting obstacles for your character to overcome. As a slight variation, you could always have her use a 'beginners' version of the magical mechanism, which doesn't include a 'stop' button because 'stopping' the laws of physics will have *interesting and long reaching* consequences which pausing does not. A mechanism with a 'stop' button, therefore, is for those with advanced skill/training/experience/common sense/wisdom, etc. [Answer] How does he see, etc? I came up with a solution for a related question [here](https://worldbuilding.stackexchange.com/questions/19834/time-no-longer-passes-except-near-intelligent-creatures-how-does-the-world-cont/19921#19921), 4 months before this Q. The “simulation hypothesis” is the only way to make it work, and it works *naturally*. > > Normally, physics is computed/rendered “as needed”, with shortcuts taken where possible. Intelligent minds, in particular, are the driving point and are always rendered in full detail with very fine time steps. Things in the immediate environment need to be driven to sufficiently high resolution, too. But if you look at a pool of water that has been unobserved for some time, > > > ① it jumps ahead without realizing states in between. (See Greg Egan’s short story Dust that became expanded into Permutation City.) > > ② entropy and information content is used to deliver only what’s needed. There is no need to get every molecule of water in its exact position; an indistinguishable lot and bulk properties is all that’s needed. > > > For this case, consider a special case of my referenced answer where time passes for *one person* rather than only around people, which is the context of the older post. Instead of being the result of bugs, it would be a real feature: an administrative mode capability. Just as we have tools to esplore the state of a suspended process, it would make sense to have this feature designed in for use by the builders. A special token in-universe, which might appear as a [gold watch](https://en.wikipedia.org/wiki/The_Girl,_the_Gold_Watch_%26_Everything_(film)), provides admisistrative access. [Answer] Tachyons. Also known as the plot device particle. In short, you aren't speeding up insanely fast but still slower than light. You are speeding up *infinitely* by converting yourself into tachyons, the only thing in the universe capable of traveling faster than light. Due to a plot-convenient way to pseudo-science what happens when you go faster than light, while going the speed of light requires an infinite amount of energy from either side, going faster than light decreases the energy requirement until you get going infinitely fast as a tachyon requiring zero energy. What does zero energy mean to you? It means you don't normally interact with the real world; if you got the conversion all the way, you are completely intangible to the real world and it to you. Of course, that means you are everywhere in the universe at once, so maybe it might be better to slow down *just a smidge*. And that smidge now means that photons can make an impression on your retina (and also that you don't lose track of where in the universe the Earth is). You might quibble about whether photons you ram with your retina are taken out of circulation so that you won't detect them the next time you pass through that particular location or whether you interact with them so weakly that only you notice them but they don't notice you; but either way it wouldn't affect normal time because unless you are soaking up every photon for a few million miles, the blip will be too fast for any human or most electronic eyes to catch. But you know what? You aren't limited to going 1 mph short of infinite speed. Do you see a bullet making its way toward your friend's head that you think shouldn't be there? Well, take your time. As you slow down, your energy increases and you are increasingly able to influence the world. Lean against that bullet for a subjective hour, and I'm sure it will adjust its path to miss your friend's head. I suppose gravity might be an issue with you going that fast, but what the weak interaction similar to the photon interaction doesn't do in that regard, the tachyon field sustaining you makes up for. It's a protective measure put in place to, again, keep you from occupying every point in the universe and losing track of Earth; if you get too far from it, the weakened field means you start to revert back to normal matter/time and feel the effects of everything all over again. Good thing tachyons don't need oxygen! [Answer] I propose the device doesn't stop time, it changes the users nature and matter. Turned into an inter-dimensional-energy-being the subject steps out of the third dimension and is able to stay in a single moment of time. Observing and interacting with a single state of the universe through new senses and capacities, not based on time-affected particles like photons or air molecules. Gravity and mass still exist, and your character can phase through matter or move it changing her own gravity, which is done instinctively in her new physiology. Doesn't need to breath in this state because her body is no longer bio-chemical. [Answer] The answer to this is simple, actually--you are over thinking it. **Anyone, anything not time stopped goes on as normal. Anything the person touches has normal physics applied to it, because their "field" of normal time is extended over the object.** Example: A ball was thrown at when time was stopped, now hanging in mid air. If a time stopper touches the object, you can have one of two things occur, either the object continues on in the trajectory it was thrown, or it simply drops, being "reset" by the time stopper's field, and when it comes into the field the normal time/space, it simply becomes a ball that's hanging mid-air, which now has gravity applied to it. Anything touched restarts. Rules: * The larger the object, the more "time" it takes to adjust to the "normal" field of the timestopper. So a car takes a little bit to work. * Touching people can restart them. However, if the timestopper has control over whether or not they can extend their field, this may be something that they can prevent as they figure out how it works. * Something like the internet may or may not work, depending on if the time stop is world-wide/universe-wide or localized. If it is local, then, there's a pingback to satellites in real time. If it is worldwide, then you have an issue. I think the same can apply to light switches. Anything that interacts with the time stopper does continue on as normal--so photons move because the person perceives them. They can breathe because the molecules they have contact with are occupying their specific space/time. *EDIT: A comment regarding the sun has lead me to clarify here. Physical objects require touch. Photons require perception of the time stopper. So the sun still shines, once she sees it anyway--and once any other creature she'd brought into the bubble sees it as well.* In Doctor Who, the time vortex did not exist until they discovered it. Think about what that means (not that it's anything like your universe). It means that the perceptions of the time traveller have an impact on how things work, that understanding a concept caused it to come into being. The kind of science applied here (although you aren't looking for it to be sciencey) is quantum mechanics and beyond. As long as it is consistent in nature, it should in narration. Why it works is not as important as how, as you will find in any time travel story. [Answer] Other people have already proposed that instead of actually stopping time, you just go really really fast. So how fast can one go? Human neurons carry thoughts at [70 to 120 m/s](http://theconversation.com/it-feels-instantaneous-but-how-long-does-it-really-take-to-think-a-thought-42392). That means it take 1 to 2 milliseconds for a thought to go across the brain. The brain consists of 100 million cells, so that thought has to move past around 1200 cells on its way across the brain. Lets say we create some kind of magical copy of a mind that can work at the very fastest possible speed. The very shortest time in which something can happen is the [Plank Time](https://en.wikipedia.org/wiki/Planck_time) of about 10^-43 seconds (a trillionth of a quadrillionth of a quadrillionth of a second). If the thought could move from one cell to its neighbour in Plank Time, it would only take around a 10^-40th of a second. This is so ridiculously fast that one would experience a billion years pass whilst waiting for a beam of light to cross a billionth of the width of an electron. For all practical purposes time has stopped. Quantum mechanics would [appear to prevent this](https://en.wikipedia.org/wiki/Limits_to_computation), but there is a loop-hole which I'll get to in a minute. Instead of eyesight, your perception of the universe is replaced by a ridiculously good mass sense. Mass changes the shape of space-time. It does not necessarily require direct sampling of anything within space-time to detect it. By "ridiculously good" I mean that you can even sense the implicit mass inherent in energy (E=mc^2). You can warm in sunlight and cold in shadow because there is more energy (and hence implicit mass) in the sunlight. You can read because the ink adds mass to the paper. What about interacting with other objects? Well to make a physical change you need energy. The faster you use that energy the more power is needed. Changing something whilst experiencing time flowing at a hugely accelerated rate is just not possible. What you can do however is plant a spell that will make the change in the very near future. Changing the course of a bullet in Planck Time would require impossibly vast amounts of power. Giving a spell enough power to deflect the bullet over the next microsecond would be have much more reasonable requirements. So - you can accelerate your cognition, explore your surroundings, and initiate changes that will occur in the very near future. The only remaining problem is the power requirements for thinking this fast. As I said, there is a loop-hole: reversible computation is free. You only have to pay the price for what you take back to your normal flesh and blood brain. Try to remember the entire experience? Impossible. No memory at all? Practically free. A single blurry memory as a clue? Well that could be possible. [Answer] It's a fascinating ability to play with and one that I have used in short stories myself. The result I decided on is basically two-fold. Interactions between energy and person are based on the person's observation. Interactions between matter and person are based on the person's physical interaction. It meant that if you roll a ball, imparting kinetic energy, the ball impacts air molecules "unfreezing" them until it passes, until there is only potential energy left. So, if you pick up the ball, hold it still, and release then it will remain in place in the air. The reason I expand energy into observation is that without it light would also freeze, every time you would freeze time the character would be placed into a soundlessly lightless abyss. Which isn't terribly fun to work with and not what you're after. To help you understand my model I'll answer your examples. > > If she turns on a light, she's drawing electricity which is coming from a coal power plant, no? > > > It would yes, but can the character observe the coal plant? If not then nothing would come out of it. Note that if she could observe it, then the people running the plant wouldn't be unfrozen. Only the plant. Selective time stops can be dangerous. Additionally carry a flashlight :) > > A car frozen going downhill is stationary, but if she rolls a ball across the room it continues to go. > > > The car has not been imparted energy by the character, however, if that imparted energy were to stop then the car would refreeze. e.g. a ball is on a hill, they kick the ball up the hill, the moment the ball is about to roll back down it freezes. > > Why does the sun not stop warming her? > > > Because she can observe the sun, and thus, it remains. [Answer] If your setting allows a controlling entity (it's either in a computer simulation, or is actively supervised by an omniscient and omnipotent God), then you don't have to care much about physics: just like in a computer game, you can selectively stop events from happening, while still having access to all information about the game state (no need to interact with photons to see, if they are also part of your simulation) If you don't want to go that route, then sorry, your character will not be able to see, hear, breathe, or even move. If the speed of light becomes zero, that will be a pretty weird singularity, I don't even know if we have any answer to how physics will work in that setting. Instead of stopping time, you could speed your character up to an extent where the world *seems* to be *almost* standing still. Time still flows, but very slowly. This has the benefits of [imposing a challenge](http://tvtropes.org/pmwiki/pmwiki.php/Main/InvincibleHero?from=Main.BoringInvincibleHero) upon your heroine: she doesn't have all the time in the world to do whatever she wants, she still has limits. However, you have to give her the required secondary powers, to keep her from burning due to the friction and compression of the air around her. You can take a look at the [Fine Structure](http://qntm.org/structure) stories for a realistic portrayal of super-speed. ]

[Question] [ A common trope across multiple mediums and genres is [roofhopping](http://tvtropes.org/pmwiki/pmwiki.php/Main/Roofhopping) (WARNING! Tv Tropes), where individuals are seen rapidly running and jumping between buildings as a form of travel. For the setting, consider Generic City, a sprawling metropolitan area. On the same block, buildings are 10–24 ft (~3–7 m) apart. Most roads in the area are 2–4 lane streets. Building heights can vary some, but often not by more than 1–2 stories. Most permanent structures on the sides of buildings are fire escapes and garbage chutes. Many times, the individuals involved have some sort of superhuman abilities. What I would like to know is, **for a normal human being, is roofhopping in Generic City possible and could it be quicker than simply running on the ground?** If so, why? If not, what would need to be changed about the infrastructure of Generic City for it to be possible/feasible? [Answer] It’s not possible to the extent you’re hoping for. Most modern urban areas have a fairly consistent pattern in which buildings are broken up into blocks of various dimensions and separated by roads. Within a particular block many buildings are divided by small alleys (often to accommodate fire escapes). In my experience in Manhattan, these tend to be between 5 and 8 feet wide, but can change depending on whether you’re on a primarily commercial or residential block. The roads that break up the blocks vary in number of lanes, sidewalk width, bike lanes, and other features, but the smallest urban road is typically a one-way street that is wide enough for parked cars on *at least* one side of the road and one lane of through traffic. A vehicle lane is typically about 10 feet wide, but an additional 5-10 feet is usually provided to allow for street-side parking. An additional width of at least 5 feet is sometimes allocated for a bike lane, and then you also have to consider sidewalks. And remember, these are the smallest one-way streets — an avenue is [much, much wider](http://www.nyc.gov/html/dot/downloads/pdf/nycdot-streetdesignmanual-interior-lores.pdf). The [guinness world record](http://www.guinnessworldrecords.com/world-records/longest-standing-jump-between-two-objects-(parkour)) for the longest standing jump (achieved via parkour) was 10 feet 4 inches (3.15 meters). Looking at the distances above, a skilled parkour jumper should be able to jump between buildings *of comparable height* within a city block, but would have very little hope of jumping between street blocks. Height, however, is of major significance. Without consistent grips on the side of a building, jumping from a shorter building to a taller one may not be feasible. Likewise, if the height difference is too great, you may not be able to safely jump from the taller to the shorter. As the below image of Manhattan will show you, building height varies drastically even in height-restricted areas free of skyscrapers. All it takes is a height difference of 2-3 stories to make a transition slow at best and impossible at worst. [](https://i.stack.imgur.com/MX86y.jpg) Even under ideal conditions, the speed of traversal is unlikely to be better than running on the road or sidewalk unless your start and end points are on rooftops. Rooftops are rarely flat and often have structures or objects on them that will impede your progress. Long distance jumps also require a good deal of energy, and performing many of them in short succession may be more exhausting than simply running at a constant speed at street level. When you throw in the reality that wider avenues are commonplace, your rooftop traversal will simply be interrupted too often. As a final note, even games that feature parkour prominently in clustered urban areas (such as Mirror’s Edge or the Assassin’s Creed franchise) make it clear that jumping between “blocks” simply isn’t feasible. To get around that, they use environment props such as wooden beams, tight ropes, or zip lines to cross roads. Wall grips are everywhere, even where they make little logical sense. Buildings with major height differences have soft landing zones to enable a jump from dangerous heights. Building heights are more-or-less uniform and wide avenues are rare. Looking to these cities, which were literally designed to make rooftop parkour possible, is a good way to inform parkour-friendly city design. Be aware, however, that these games don't truly take runner fatigue into account. Scaling buildings requires a great deal of effort, which means uniform building height would be much more important. [Answer] In many fantasy cities (and some historic) upper floors of buildings are often built wider than the lower floors because real-estate is at premium. In some cases buildings might meet above a street (or come close enough to be easily jumpable). If you want rooftop parkour to be a thing, just take the above premise and run with it; even for a present day/futuristic setting, roof-running might be feasible in historic districts, while fresh development areas are not so accessible. [Answer] The best place for roof-hopping would be a slum - I have Dharavi (Mumbai) in mind, but I believe this can work in other such areas as well. These slums are unplanned or semi-planned areas in urban agglomerations with very narrow streets, and individually-built structures which are not uniform, but typically have the same number of storeys. [](https://i.stack.imgur.com/bpurS.jpg) Chasing someone through such an area at street level would result in innumerable collisions and a quick end to the chase. However because the structures roofs are more or less aligned (with some dramatic exceptions), it makes more sense for the chased person to take to the rooftops. Such rooftops are built strong enough to take the load of multiple people, and torrential rain. [](https://i.stack.imgur.com/lJYXH.jpg) [](https://i.stack.imgur.com/JpmNO.jpg) [Answer] Several people have mentioned *Assassin's Creed* and other similar games featuring older houses in cities with narrow alleyways. The film *Crouching Tiger, Hidden Dragon* also showed people running across rooftops. It's a nice idea. The trouble is that roofs simply aren't designed to take the kind of point weights that you get from an adult landing heavily on one foot. If you stick to the ridges then you can probably get along, but if you tread on the roof itself without crawling boards then an adult is **very** likely to go straight through. They're only designed to take enough weight to allow for distributed pressure such as snow - and in areas with heavy snowfall you see much steeper roof pitches to reduce that load. Even for sticking to the ridges, they're not intended to take the point weight of a falling person. So your medieval parkour specialist would be fine until they had to jump across their first street. On landing, they'd go straight through the tiles/shingles/thatch and land heavily in the room/attic below. The chaser simply has to nip down to ground level, go in the front door, and remove the parkour specialist on a stretcher. [Answer] # Yes it's possible **[Parkour](https://en.wikipedia.org/wiki/Parkour)** This is actually a real sport. People can train to do seemingly inhuman feats like falling from 10–15 feet uninjured in real life.You should go look for some parkour videos and their stunts, it's ridiculous and entertaining for me. While I'm not clear of how NYC layout is, it should be entirely possible to parkour across roofs. Whether it's faster than running on the ground is debatable. Running on the ground would usually be faster if there are no obstacles like giant roads choked with cars at 50–60 miles a hour. Running on roofs could allow a person to skip these ground obstacles but if the gap between roofs is too big... # How to improve the city for parkour Have you seen Mirror's edge? It's a game about parkour basically, I recommend checking it out. To have a city conducive for parkour, we would need it to have plenty of pipes that allow climbing, zip lining ropes, closely packed buildings, lots of scaffolding and climbable walls. This would allow a skilled and experienced parkourer to traverse across the city easily. [Answer] > > for a normal human being, is roofhopping in Generic City possible and could it be quicker than simply running on the ground? > > > Possible, yes. The trick here is that you would not be able to take direct route. You may be able to get from 1st to 55th street via rooftop, but you may have to go across 100 streets to do it. For example getting from 2nd to 3rd directly may not be possible, but you could go a few blocks on 2nd to a pipe that sticks out, and then get over to 3rd, but then have to go 5 block back to find another spot to cross to 4th. You would need to know the city very very well, but it is possible. Faster, no. What makes it possible is that you can travel from point a to b by knowing where some short cuts are, even if those shortcuts are 1-2 miles out of the way. It's always going to be better to go in a straight line. Now if you could not take the road, then roof top access may be faster. But your basically saying that running on the tops of buildings is faster then not moving at all. > > what would need to be changed about the infrastructure of Generic City for it to be possible/feasible? > > > In Tampa FL, and Grand Rapids MI at least a few buildings already do this. I am sure other cities do as well. They create walkways between buildings. If your city had a lot of these walk ways you could maybe get faster via rooftop then by road. I remember an area in Grand Rapids where the roofs of buildings were actually made into a kind of park. You wouldn't even know you were on a roof top. If these roof top parks were connected then you would get a pretty straight line. [Answer] In New York is impossible except for short distances. However in other cities, escaping by running on building roofs has major **advantages** which are difficulty and danger. Running on roofs is hard for both the chaser and the chasee; both have equal chances to make stupid mistakes and end up dead, but usually the chasee have adrenaline that helps them. It is like poker a mixture of luck, skill and cold blood. If you do it right, you are safe, but at the first error you lose everything. Running on streets might be a better option if you are good at hiding or you can use cars. [Answer] Roofhopping or Parkour is a sport made to look cool. It gives you a better vertical speed, you may win against someone running up stairs (or maybe not depending of his condition). But the horizontal is not magic, you jump obstacles the fastest way possible but you could just have chosen a better way at the beginning. A normal human doesn't have the strength, the agility and the cold blood to execute the most basics move. It is not an accessible sport, it require a lot of skill and training. You have to practice in safe place hours before trying moves in dangerous place unless you want to die young. Also you expose yourself to multiple injuries and you risk your life. Le Parkour is an extreme sport, it will never be widely practice and it is not a safe way to travel. [Answer] *"for a normal human being, is roofhopping in Generic City possible and could it be quicker than simply running on the ground?"* **No, only in specific places where the buildings are conveniently arranged for that.** **Or in non-generic-modern-US cities, where in some cases it's more common for the buildings to be conveniently arranged for that.** **Could it be quicker? Not generally but yes, in some cases it could be.** There might be a lot of traffic on the ground, or you might be trying to go in directions that the streets don't go. The real advantage tends to be in terms of avoiding detection and escaping pursuit (so while it's not faster than you running in the street, it may make you faster than others), because: * Usually rooftops are mostly or completely blocked from vision from below, so surface pursuers won't know where you are or which way you are running. * Usually getting up to catch you involves time-consuming and possibly blocked passages through unknown buildings to reach the roof. * Someone choosing to run and jump across roofs is either foolhardy or has some exceptional skill/practice in doing so, so many other less foolish/crazy or skilled pursuers may stop, slow down, and/or fall. * Someone choosing roof travel may have studied the roofs in that location in advance, and have a path they know about that their pursuit does not. * If violence is part of your plan of action, there may be fewer witnesses if you are doing something like resisting arrest on rooftop, as opposed to down on the streets where most witnesses are. [Answer] I have a bit of personal experience with this and it's viable (with some important restrictions). Most importantly, no normal human will be able to jump a 2 lane road. When a block is laid out with buildings touching each other it's trivial to make your way down the row without touching the ground. It's not even too hard to make up the difference in height. Of course down is easier than up, but it's not hard to find a way and there's nothing like someone chasing you to inspire a bit of creativity. (In another situation I once vaulted a 6 foot fence at a dead run using one hand and a bit of canine inspiration.) A little practice and a reasonable level of base fitness goes a long way. Knowing the area is also a huge bonus. The main street in my hometown was like this and we used to think it was fun to make our way down the whole block this way. There were several changes of height and multiple ways to make one's way up or down. In a situation where the streets are packed due to a festival or riot this is actually a quicker way to move around. It's also a nice feeling to be up away from the crowds and a good way to avoid anyone who might be searching the streets for you (not that I know about this part from experience, it just seems very peaceful up there and nobody ever seemed to look up) Crossing streets presents the biggest problem. In theory it's possible to jump a narrow alley, especially if you get to go down one story, have a clear place to land and know how to roll. In practice I wouldn't count on it and I'd expect to sprain an ankle the first time you try it. Jumping a road that's too wide sounds like a great way to splat and die. Whenever you see someone do a jump like this in a movie it's either over a narrow alley or it's somebody with super strength. I don't have personal experience with a tighter downtown design, but I've seen cities that look like they'd be way more amenable to rooftop shenanigans. Cities built in the middle ages had very narrow streets and many have preserved the old town as pedestrian-only shopping districts. Old town in Zurich is like this. Jumping the narrow pedestrian only alleys looks totally possible (though, when I visited I was much past the point in my life where I'd go try that out) [Answer] The debate about falling through the roof seems to have been resolved by earlier answers. [](https://i.stack.imgur.com/i0DZI.png) (usefulness for furthering the storyline notwithstanding) The real issue seems to be: *What does it mean to be 'on the run' on rooftops, in terms of storytelling?* The high altitude financial district scenario is the elite version, requiring specialised skills for admission, similar to escaping by jumping in the water when the pursuer can't swim. Hopping from one rooftop to another can force non-parkour types to run from the base of one elevator to the next in hopes of catching their quarry. Attacks from the ground seem unviable, but being 'herded' into a dead end [*leap of faith* trope] by aerial pursuit is a real danger. Inaccessibility comes at the price of limited avenues of escape, and insider knowledge of the terrain should determine who wins. The mid-height scenario really only requires that both pursuer and quarry be relatively athletic and/or sufficiently desperate. Also this version is pretty much over-the-counter, in terms of not relying on crane operators or AC techs having left things in conveniently improbable configurations. Close proximity to the ground means that attacks from the ground may be viable, but allows for the option to segue the chase to ground level in a jam. Downsides to this chase style is the total lack of street signs for directional cues, along for the likelihood of landmarks being obscured by nearby buildings. Long runs of brownstone flats, very narrow streets lined with mid-rise apartment projects, and the winding and tightly packed streets of European villas are all good examples. [Google *James Bond Rome* images] The low-height variant involves street level essentially being the roofs of the buildings to start with. Basically being on ground level means crowds can be a big hindrance, random passersby could join in aid the pursuer(s) or quarry. The chase would start to resemble more of an obstacle course race, and allows for nearly infinite route improvisation. Since it is difficult to be physically inaccessible, use of soft cover, misdirection, and confusion become much more prominent strategies. Favelas (Hulk 2008) are a good example, and Pranab's Dharavi pic up there ^, as well as several cities mentioned in the bible. Even some back alleys in Salvador change level so often as one restaurant back patio connects to the next that it would feel like a rooftop chase, even though it's technically ground level. [](https://i.stack.imgur.com/KVM4p.jpg) Why should you have to pick just one? As long as you can argue the population density of Generic City is high enough, your rooftop chases could range all the way from the downtown core to the suburbs and back, if required. [Answer] Almost all the comments I've read have been about American cities, so let me give you the European perspective. Short answer: Yes, kind of Long answer: A lot of it depends on the city that your in. In rainy climates, roofs are slopping and this would make them more difficult to run across, especially if it has been raining recently. However, that doesn't mean it would be impossible. The popularity of fell running proves that running along slopes is possible, although dangerous. One flaw people have pointed out are the roads that run between buildings. In American cities, this is a problem because you tend to have wide streets and a grid pattern to your city. However, in most other countries, streets are more sporadic so there is definitely an advantage to running along roofs to cut corners. Basically, it takes practice and agility and would work best in cities with dense populations, narrower roads, low rainfall and you'd need quite specific circumstances to want to but yeah, it would work ]

[Question] [ **Closed**. This question needs to be more [focused](/help/closed-questions). It is not currently accepting answers. --- **Want to improve this question?** Update the question so it focuses on one problem only by [editing this post](/posts/71665/edit). Closed 6 years ago. [Improve this question](/posts/71665/edit) I'm trying to come up with an alternate reality where some specific invention or discovery was never made. Many inventions or discoveries in (mainly European) history were not a 'miraculous event,' but much more often just waiting to be made, given the technology at the time. Many discoveries and inventions were even made [independently around the same time](https://en.wikipedia.org/wiki/List_of_multiple_discoveries) (such as the telegraph, discovered independently by Wheatstone and Morse; or calculus, formulated around the same time by Newton, Leibniz and others.) I'm looking for some examples of those 'miraculous event' discoveries that were way ahead of their time and, if they hadn't happened then, would not have happened for a long time (if ever). I'd also appreciate some hints as to the consequences of not making this discovery or inventions. Or maybe more accurately: the consequences of this invention/discovery in our own history, that we would be lacking otherwise. **Edit:** I'm looking for inventions or discoveries which, if they hadn't happened, would have drastically changed centuries of history. To stick with my previous examples, if Wheatstone or Morse hadn't invented the telegraph, it likely would have taken another year before someone else figured it out, and in the grand scheme of things, we would still be where we are today. From the answers to this question there are already some wonderful ideas for alternate history. Such as the game-changer that modern sail rigging would have been had it been invented much earlier; Or a Roman steam engine, had Romans actually had pistons to properly utilize it; Or penicillin, the availability of which arguably played a role in many countries' willingness to go to war. [Answer] You don't really need some speculative alternate reality, our own history is full of such events. Two "missing inventions" are for example the wheel in pre-Columbic America, or the computer in the early 20th century, when Babbage’s pre-work was already close to 100 years old and vacuum tubes (triodes) and relays were otherwise widely used and available. The fore-and-aft sailing rig came only in the middle age, when the idea should have been obvious to any observant Greek, Roman, Viking, etc. sailor and shipbuilder. The chimmney is equally obvious, but was only invented by the Romans, then forgotten, and reinventend after 1000AD. Don't even mention optics. Clear glass was available since around 200BC (depending on how transparent you want it), Aristoteles reputedly made himself a pair of glasses and had even solved the laws of diffraction(!?!), but the magnifying glass took till 1100, the telescope till 1500, and microscope even longer. The Romans had a jump of 1500 years in medicine in their hands, and just overlooked it. *Seneca* (50AD) knew about the magnifying effect of a drop of water. How hard can it be to transfer that to a similarly shaped piece of glass? Very, evidently. Or their cartography: An empire without proper maps! All the necessary astronomy was known from the Greek already (and others), and the Romans had the organisational means and strategic need to do it. Would also have given the ideal opportunity to do trigonometry some 1000 years ahead of time. I'm aware it is very easy for a modern ignorant to insult the elders of having been ignoramuses. ;-) Somehow the time wasn't ripe for those inventions, although it's hard for us to imagine why exactly. [Answer] ## If there are any miraculous events, I am not aware of them. Technology, science and society don't exist in vacuum, as you noted, most discoveries are a logical next step. While it's important to distinguish incremental improvements of existing theories or technologies (like steadily raising speed of CPU clocks, or increasing precision of measurement of physical constants) from basic research discovering new phenomena and leading to new technologies (by feeding applied research with those phenomena and ideas), they both work by building on existing foundations. Main difference is, in latter you can't really predict what you will find (that's kind of a point of basic research, to find out), while in former you can make general projections and predictions on rate of improvement and limits. ## Most of the science and technology (if not all) would be discovered later by someone else if for some reason historical discoverer wasn't available. **Same works in reverse, many technologies and ideas appeared before their time, and slid into obscurity**, because there was no need of them, or there was no axillary tech to make them useful. Good examples are steam power, mechanical computers and smartphones. While they are examples of ideas or devices failing to catch on prematurely, they show exactly why that happens, and what happens later, when, figuratively speaking, world is ready and time has come for them to catch on. First [steam power dates back to antiquity](https://en.wikipedia.org/wiki/Aeolipile). It's simple, but shows that work can be extracted. However, without auxiliary knowledge, like knowledge of thermodynamics, it wasn't improved to the point of being useful, furthermore, there wasn't so much need for mechanical power back then. Through most of history, windmills and watermills were sufficient, until advancements in tools led to construction of mechanical looms and lathes, which rapidly increased demand for mechanical energy. At the same time, mechanical tools, allowed for construction of more precise parts, in greater quantity, leading to positive feedback loop of industrialisation. [Antikythera mechanism](https://en.wikipedia.org/wiki/Antikythera_mechanism) was a remarkable mechanical astronomical/astrological computer from antiquity. However, it was designed to be more precise than tools and craft of the time could build it. At the same time, there was no computer science, calculus, or even concept of "0". Because of lack of axillary knowledge and technology, whoever designed and built it wasn't able to generalise the device and thus, it remained a very specialised novelty. [Babbage's differential engines](https://en.wikipedia.org/wiki/Analytical_Engine) were mechanical general computers, designed nearly 100 years before electronic computers. That's the closest to major alternate history that I know. There was no computer science back then and there was little interest in computational power, furthermore, mechanical computers would be large, error prone and less efficient than electronic ones, but that was probably the first time in history where all the elements for computer to become reality were in place. There was steam power to drive them, there was design, tools and alloys might have been up to the task, and there was Ada Lovelace who might have been able to play the role which Alan Turing played nearly century later. However, there was little need for computers. Practical applications of early XX century computers were encryption/decryption and calculating firing solutions or firing solution tables for submarines and artillery, at the time of Babbage, neither of those were advanced enough (or even present) to warrant existence of computer. Thus, Analytical engines were never built, perhaps if there was someone else to the duo of Charles Babbage and Ada Lovelace, someone who could see practical applications the history might have played differently, but as it is, Analytical engine served as the theoretical foundation for further developments. Smartphones are quite ubiquitous nowadays, but they are not the first attempt at such device. First [PDAs](https://en.wikipedia.org/wiki/Personal_digital_assistant) appeared in 80s, but without axillary network infrastructure, cheap computational power and plentiful storage, they didn't catch on. Later, with advancements in infrastructure, processing power, batteries, screens, wireless communication and lot more, phones started acquiring new features, effectively merging with PDAs, until finally in mid 00s all was in place to begin the era of smartphone. Louis Pasteur said that "Fortune favors the prepared mind". [Have Alexander Fleming](https://en.wikipedia.org/wiki/Penicillin#Discovery) not been bad at keeping sterile conditions, or haven't been knowledgeable enough, someone else would have discovered the penicillin. It already was known that some moulds had antibacterial properties, and research was done in that field. Alexander Fleming certainly wasn't the only capable of that discovery, but chance decided he had greatest opportunity, and he used it to the fullest. Now, this doesn't mean there aren't discoveries fitting your criteria, but I am not aware of them. [Answer] As a meta answer look at different cultures before we had world level communication. Why were some things invented at such drastically different times, and others not at all. Inca, Maya, Aztec civilizations never invented the wheel. Why not? The Plains indian culture took a radical shift with the introduction of the horse. (Imagine hunting buffalo on foot.) Imagine North America if horses and wheels were here by AD 1000. The Americas didn't have a usable saddle animal nor a draft animal. Could moose have been domesticated? Why did the populations of camels and horses die out? (Llamas are members of the camel genus, but are too small for riding, and apparently won't pull.) The horse collar was much later than it had to be. Prior to it, a band around the horse's neck was used. The horse couldn't pull hard on it because it cut off his air. There was a reason that chariots had 2-4 horses on them. Once you had the horse collar, you could use a horse as a draft animal. The moldboard plough. When it did come in, it allowed the tillage of northern soils which were too difficult to manage with the mediterranean scratch plough. The non-suitability of northern soils for agriculture put a limit on the Roman empire. Centerboards/leeboards on sailing ships. Not practical on big ships, but small boats with one of these can sail much closer to the wind. This would have changed the whole history of naval warfare and smuggling. I suspect that many of the innovations in sailing ships could have occurred earlier. E.g. A schooner like the Bluenose can be handled with fewer men, and has better upwind handing. (Fore/aft Bermuda rig) Schooners with gaff rigged sails were introduced by the the Dutch in the the 16th century. I don't see why they couldn't have been done 2 centuries earlier. Math: There was no reason for zero to take so long to get from India to Europe. Romans used what amounts to an abacus for doing arithmetic. It would have been such a simple step to go from there to a decimal notation. Imagine Rome with double entry bookkeeping. When Harrison was building chronometers, mariners were calculating their longitude using lunar distances. Initially a difficult problem taking several hours of calculation, with later tables, the process got down to about 10 minutes. To do this earlier would have required several prior breakthroughs in math -- tables of sines; spherical geometry, but give the Romans the zero, and this may have occurred much earlier. Germ theory of disease, and the attendant revolution in public health. Another source of inspiration is to look at some of the appropriate technology aids in the third world. In the 50's and 60's India was subject to famine. Now India is a food exporter. While the Green revolution had a significant impact, far bigger was the simple expedient of lining grain silos with plaster or cement. Rats were eating half the crop. One of those "Duh!" ideas. [Answer] ## The Discovery of Penicilin According to [Mighty Wiki on PCN](https://en.wikipedia.org/wiki/Penicillin#Discovery): > > The traditional version of this story describes the discovery as a serendipitous accident: in his laboratory in the basement of St Mary's Hospital in London (now part of Imperial College), Fleming noticed a Petri dish containing Staphylococcus that had been mistakenly left open was contaminated by blue-green mould from an open window, which formed a visible growth.[29] There was a halo of inhibited bacterial growth around the mould. Fleming concluded that the mould released a substance that repressed the growth and caused lysing of the bacteria. > > > So if Fleming had cleaned his lab properly, PCN would not have been discovered (at this time). Crucial: Oh yes. Without PCN many people would have died due to (seen from today) most simple illnesses. Unlikely: Yes. If he had followed the rules of the lab, the petri dish would have been cleaned and PCN never discovered. [Answer] # [Maxwell's equations](https://en.wikipedia.org/wiki/Maxwell%27s_equations) > > Hertz did not realize the practical importance of his [experiments]. He stated that, > > > "It's of no use whatsoever[...] this is just an experiment that proves [Maestro Maxwell](https://en.wikipedia.org/wiki/James_Clerk_Maxwell) was right: we just have these mysterious electromagnetic waves that we cannot see with the naked eye. But they are there." > > > Asked about the ramifications of his discoveries, Hertz replied, > > > "Nothing, I guess." > > > Said by [Heinrich Hertz](https://en.wikipedia.org/wiki/Heinrich_Hertz) just as he had for the first time proven the existence of radio waves. Maxwell's equations are the theoretical foundation for everything concerning electromagnetism, which in turn is the foundation for 1) **generating electricity** and 2) **radio**. If Maxwell had not formulated these equations, electricity and radio would have been seriously delayed. [Answer] The discovery of [Czochralski process](https://en.wikipedia.org/wiki/Czochralski_process) (a method for manufacturing single crystals) by a Polish scientist [Jan Czochralski](https://en.wikipedia.org/wiki/Jan_Czochralski) was an accident. Quote from Wikipedia: > > He discovered the Czochralski method in 1916, when he accidentally dipped his pen into a crucible of molten tin rather than his inkwell. He immediately pulled his pen out to discover that a thin thread of solidified metal was hanging from the nib. The nib was replaced by a capillary, and Czochralski verified that the crystallized metal was a single crystal. > > > This method is used to this day for manufacturing of semiconductors. If he didn't have a crucible of molten tin on his desk or had insufficient scientific background to recognize the importance of what has just happened, the development of modern computers would be delayed. [Answer] Not quite what you're looking for since it's a modern one, and I'm not sure how many people outside the field are even aware of the revolution that green fluorescent protein has brought to biology. It was discovered by Osamu Shimomura in the course of marine biology research, as the basis for the the bioluminescence of a certain species of jellyfish. Decades later, in molecular biology, many people were working on reporter assays--ways to determine whether a protein is being produced in a cell, and where. Many were available, but all had their flaws. The reporter assay people (in particular Martin Chalfie's group) found that green fluorescent protein (GFP) perfect solution to their problems. (By this time history was determined--Chalfie's was one of three groups simultaneously trying the same thing.) You could make cells express hybrid proteins with a green fluorescent protein attached, by splicing the GFP gene into the gene that codes for that protein. Then the GFP would fluoresce green when illuminated with blue to ultraviolet light. In this way, you could see the location of the protein, under a microscope, even in living cells! (Chalfie used it to study nematode development--he could see the GFP shining in living worms.) GFP is now used routinely in molecular biology, to study patterns of protein expression and protein function. (Or one of it's variants such as mCherry, many of them created by Roger Tsien's group by modifying the GFP sequence.) But what if GFP, this decades-old discovery in marine biology, had not been out there for them to use? If Shimomura and his mentors, Hirata and Johnson, had not been studying this species of jellyfish, there's no guarantee that anybody else would have. It just didn't seem of any practical importance. I'm pretty sure the reporter assay people wouldn't have thought, hey, let's study jellyfish. Other technologies would have been developed for reporter assays, and MAYBE they would have been just as good? I'm not sure. It's very plausible that there could have been a little less funding for marine biology research, or Shimomura, Hirata and Johnson could have chosen different projects. To make it even more of a near miss, Shimomura lived in a city only 25km from Nagasaki during the atomic bombing. How would biological history have gone if he had been visiting that day? It's not exactly the sort of history-altering discovery that you're looking for, but it may provide a schema for the kinds of things to watch out for. Important discoveries that in some way depended upon some other, seemingly irrelevant discovery. [Answer] The single most "miraculous discovery" in my opinion is the theory of [Special Relativity](https://en.wikipedia.org/wiki/Special_relativity). Even having reviewed all the data available at the time Einstein came up with it, I cannot see how he came to the conclusions that he did. Together with [General Relativity](https://en.wikipedia.org/wiki/General_relativity) the concept is not only a work of genius, together they are one of the most creative works that I believe humans have created. I really think that [relativity would have been easy to miss](https://hsm.stackexchange.com/questions/622/the-motivation-for-relativity-theory/625#625), and I do not believe that any of Einstein's contemporaries would have come up with the ideas. Without relativity, we would continue to doubt Newton's laws of motion and understanding of gravity, as we know of [counter examples](https://hsm.stackexchange.com/questions/2818/why-were-newtons-laws-accepted-when-there-exists-a-counter-example). In a practical sense, we would not be able to account for our artificial satellite's orbits. [Answer] Science works in a way that nobody is really irreplaceable. However, delays could have happened. I can talk for computers. If IBM (it wasn't called IBM back then) was failed to deliver a computer that helped with US census data in 1890, people might have kept their mindset about computers being useless toys, and this could have delayed computers and related technology for a long while. But probably not as long as you would like. I would guess it might have taken another 40-50 years and it would have delayed a lot of the advancement we have today. [Answer] Telescopes were invented in the Netherlands about 1608. Several lens makers claimed to have done so. Hans Lippershey is usually credited. Suppose that Hans Lippershey was the actual inventor and the others were early adopters of his discovery instead of independent inventors at the same time. Suppose further that one story is correct. This story says that Lippershey's children were messing around with lenses and discovered that a certain arrangement made distant objects look closer. According to this version, the discovery as a result of the children happening to play a particular way and Lippershey recognizing the practical usefulness and marketability of telescopes. Either part of the event might not have happened. Thus it is possible that telescopes were a largely accidental discovery instead of one that would have been made in a few years anyway. Thus telescopes, with maritime and military uses, might not have been invented for decades or centuries. And thus they might not have contributed to scientific discovery for decades or centuries. Thus, if that story about the invention of the telescope is correct, comparatively minor events in the Lippershey household could have changed history significantly through delaying an important invention. [Answer] It is not so much an unlikely invention as a possibly unlikely social development, but **The Industrial Revolution** deserves mention. Why did it not take place earlier, in Rome or Bagdhad or China? We don't have access to alternative histories to know whether it was inexplicably delayed here, or whether it was a one in a thousand chance which everywhere else was prevented by conservative attitudes and vested interests. Certainly in the early Islamic world and in China (twice), many of the component pieces were in play, and were then suppressed. [Answer] It's obvious, but... **The Internet.** Seriously. It started as an information-sharing protocol between servers, and branched out because some OTHER people with servers wanted in. It would have been so, so easy for some CEO to say "Okay, good, now we're gonna keep this technique a secret so our competitors can't use it." If the Internet never got started, computers would never have become the massive driving force that they have - instead of even Grandma needing to go buy her "Internet box," computers would be the toys of scientists and researchers using them for robots and the like. They wouldn't be half as advanced, either, considering that researchers don't devote as much effort to things without a demand. We'd still be stuck in the 90s without the Internet. [Answer] **Want to improve this post?** Provide detailed answers to this question, including citations and an explanation of why your answer is correct. Answers without enough detail may be edited or deleted. **Galois Theory** <https://en.wikipedia.org/wiki/Galois_theory> in the [Aftermath] section: "Galois' theory was notoriously difficult for his contemporaries to understand" also check <https://math.stackexchange.com/questions/772810/mathematicians-ahead-of-their-time/773617> ]

[Question] [ > > The knack lies in learning how to throw yourself at the ground and miss. > > > -- Douglas Adams. > > > Humans can't fly. Not themselves. Sure, we can climb aboard a plane, a hot air balloon, or a rocket ship. But we can't flap our arms and soar. Since we can't fly, we had to find other ways of moving around. Since walking wasn't fast enough, we developed a number of technologies for moving around, most of which are wheel based. Carts, bikes, cars, trains. We use those technologies not only to move ourselves around, but to move other stuff around too. Birds can fly, bats can fly, and [even squid are getting the hang of it](https://www.youtube.com/watch?v=iMq89roPycI). Some birds are pretty clever too. I can imagine a society of birds, instead of humans. Since flight is so much faster than walking, I can imagine birds not having the need to develop faster modes of transportation. It's also so vastly different from ground based modes of transport, that I doubt they would develop any method of moving heavy loads over the ground (and thus the wheel). So would a society of flying beings (not necessarily birds, they might have hand-like appendages) develop the wheel? [Answer] I would certainly expect the wheel to be invented. Sure, the society can fly, but can barrels of fine wine, flour, or iron ore? If the society grows large enough, it will eventually need to transport heavy goods and that practically requires the wheel. Whether food, metal, or wood, pretty much every soceity starts to transport goods heavier than one person can easily carry for the whole distance. Flying is hard, trying to transport heavy goods that way prior to the invention of an airplane or hot air balloon just wouldn't happen. Now, if there are no tamable herd animals such as ox or horses to pull a wheeled vehicle, then the wheel might not ever be needed, but as long as there is some flightless animal they can use, some ground based form of transportation would likely be invented. While wheels usually arise here, sleds of some form could also work. As others have mentioned, wheels in other forms such as millstones and pulleys, even door hinges would also still be useful in your culture and I would expect them to be invented. [Answer] ## moving things around (mathematics argument) The wheel, or basically any spherical object, has the advantage of being the simplest shape which center of mass remains at the same height when rolling (something cubes don't have for example). That makes it the easiest shape to move around, thus the easiest way to move things around. This is mathematics, and mathematics are universal. However, it is totally imaginable that rolling things on tree trunks (like older civilizations used to do), or just have them carried around by animals (cows, horses...) would be enough. --- ## going places (biology argument) If your flying beings are anything like humans, they probably are lazy too. It is actually a principle of biology that living things try to get the most done with the least energy spent. So eventually, they'd want a way to go places without having to fly. Just biology. However, because they wouldn't be afraid of falling from heights, they might develop some sort of air gliding devices before carts. That might just be enough. --- ## efficient machines (engineering argument) Pulleys, gears, belt transmissions... All these mechanical systems somewhat derive from the wheel. And up until now, mechanical engineers have not found better suited shapes for the work. They allow to leverage the energy efficiently and regulate torque. --- ## conclusion: yes So basically I'd say, yes, the wheel would be invented... just maybe a little later. But the circle is just a very useful shape. Of course, environmental factors might delay its invention. I'm thinking tiny islands (like [Panama's San Blas](http://en.wikipedia.org/wiki/San_Blas_Islands)), dense jungle and steep mountains, swampy/sandy ground... [Answer] The wheel is not necessarily an automatic development for humans. Classical Mesoamerica (Mayans, Aztecs/Mixica, etc.) didn't have the wheel. At base, the issue there was a combination of lots of dense forest and jungle, on the one hand, and a lack of large domestic animals on the other. So things like carts just didn't really click, as it were. So in direct answer to your question, you can have it either way, as you choose. There's no necessity about it. If everyone can fly, they might find wheels useful anyway for cartage and so forth, but on the other hand, they might not. [Answer] Rephrase your question to > > in a society of walking beings, would the wheel ever be invented? > > > and you have the answer. The wheel is not about **enabling** anything. The wheel makes it only **easier** to transport goods and enable higher capacity. The same would apply flying beings. If you observe the pidgeons, for example, you will notice they prefer walking on short distances. Every being prefers doing things with the minimal energy required. Why do we use rivers as transport means? If you study a bit river transportation, you'll notice, that the speed of that transport is slower than the walking speed. Why do people used it? Because it allowed them to transport more goods they could carry. [Answer] > > So would a society of flying beings (not necessarily birds, they might have hand-like appendages) develop the wheel? > > > Yes. Pulleys are still one of the more vital simple machines, and flighted brings would still need force multipliers. If anything they might need pulleys *more* given their freedom of movement. [Answer] Definitely. This is a simple answer, but consider this counter-question as definitive proof: *In a society of FLIGHTLESS beings, would WINGS ever be invented?* The answer, quite obviously, is yes. Rhe transference to and utilisation of different dimensions is such a natural step in improving efficiency and effectiveness of transportation, that I would argue the ability to do so is a requirement for the definition of "society". [Answer] There is an important conceptual precursor to wheeled transport: carrying stuff from one place to another. Humans and our near relations (e.g. *Homo habilis*) had a penchant for carrying things long distance. You don't spend days smashing rocks into useful shapes and then just leave them there. Our closest living relatives, the chimps, will carry one thing maybe 3 meters, but even though they are nomadic, they never got the hang of carrying things long distance. If you're not carrying many things long distances, cartage doesn't improve things for you and then wheels become a mere curiosity. Cartage was not originally any faster than walking because wheels like a road. I suspect that the wheeled vehicle was difficult to envision because the geographic distribution suggests a great deal of copying from neighbors. [Answer] Do not only think about the wheels of a car. The wheel is a very important invention used not only in transportation. They are also used as pulley,l waterwheels, gears and a lot of other functions as well. Even if your species can fly, transporting stuff in the air is not considered very efficient because they can't lift a lot of extra weight. Transportation would still rely on boats, and wheeled vehicles would still be useful. [Answer] I am going to offer a counter-trend answer here and say that there is little to **no need for the wheel** This is an alternate world theory for reference. **Assumptions** * Humanoid, with human level intelligence * Human penchant for setting down roots (creating cities etc) * Human penchant for expansion and trade Basically I am making sure I point out that this is an "if humans could fly" scenario. The primary reason for creatures that can fly to create and utilize the wheel is encumbrance. Being speedy and able to fly is great but that may not facilitate the transportation of goods. Its not the only reason to consider the wheel a likely technology but it seems the most obvious. *Moving Stuff* **Alternate World** * A world with a significantly lower gravitational pull * Thats it really Now, there are a host of other concerns with a low gravity planet. Can the atmosphere be created maintained etc. But lets skip over that for the moment. Low gravity would allow flying creatures to carry significantly more around with them reducing the need to develop the wheel. Could they still come up with it? Sure, it just wouldn't be as impactful and may get skipped over as air based travel would be easier to use and less costly. Maybe instead of the wheel and ground transport technology goes the direction of blimps and things earlier on because it is easier to do. Just an alternate idea/answer. [Answer] Not a directed reply, but more of a comment about the supposition of meso-american cultures not having the 'wheel'. I would like to some sources on this since most reputable sources i have found will discredit this. <http://tcmam.wordpress.com/2010/11/11/did-pre-columbian-mesoamericans-use-wheels/> Even Wikipedia discredits this notion. The wheel was used in many aspects of culture from children toys to sealing temple doors. They did not have a chariot or cart pulled by their pack animal. And yes south America had 1 pack animal. So i would assume that all of the 'simple machines' would likely be too useful for a civilization to not discover. Levers, pulleys, wheels, axles, all things that are used in many devices for all of mankind. Even birds have been caught using levers. So one can assume as mentioned that the lower energy cost of moving carggo on the ground would well be worth it. [Answer] Per Liath's comment, it would depend on whether or not these flying beings have legs/are capable of walking, or if the only appendages they have are wings, and/or their body structure in general. If it is the former and assuming that their physiology is similar to Earth's birds, I believe that it may be likely that they would develop the wheel eventually. Constant flying (near 24/7) would be awfully tiring, and we do see flight-capable birds on the ground and wandering around. Goodness knows I've seen some that decide to slowly walk across the road where there's a lot of cars and they're at high risk of being run over - and I'm always thinking, *'you have wings! Why don't you just fly across the road?! Surely it'd be safer/easier!'* but seeing as they don't and decide to leisurely make their way across... my guess is that they're resting their wings. It doesn't seem to make much sense otherwise. So, if these beings are also capable of spending some time on the ground (or a flat surface of some description), then yes, I do believe it's likely. If say, however, their society is based in the trees or something, which they hop or fly around to, and there aren't any sort of "platforms", or walkways between them, then a wheel would be next to useless for them. Wheels are used for transporting things from point A to point B, but if the path between point A and B aren't suitable (don't cater) to the usage of wheels... ### TL;DR: It would depend on their **A.** physiology, and **B.** societal infrastructure. **[EDIT]** And after reading some of the other answers and thinking about it some more... No *one* society exists in a vacuum indefinitely - sooner or later, they'll discover another completely different one. So another thing to ponder would be, would there only be just the *one* society of flying beings on that planet? I mean, other nearby societies may be ground-based. Assuming that some form of trade may one day occur between this flight-based society and other non-flight-based societies... sooner or later, someone's going to invent the wheel, would be my guess. [Answer] **It depends on a number of factors**. Not all civilizations developed the wheel, and of the civilizations which did, not all of them used it for transportation (another answer cites the Maya as a civilization of this second type). But while a society of fliers might not develop wheeled modes of transportation for themselves, they might develop the wheel for other reasons. It wasn't until the development of mechanical engines that wheeled transportation gained any speed advantage over traveling by foot or riding, and those engines are, historically speaking, a fairly recent development. **For most of the wheel's history, its advantage was scalability, not speed**. A human with a wheelbarrow, or a beast of burden hooked up to a cart, could transport much larger and heavier loads than that same person or animal could carry unassisted. Speed might suffer some, but you could carry much more stuff with fewer people or animals. You could also carry large-sized loads that, while not necessarily heavy, were too awkward to carry on a single person or animal. **Why did your fliers not see that need?** Are they strong enough to carry any load they could imagine while still flying? Is the local terrain not well-suited to wheeled transports (arid and sandy, perhaps, or covered with snow, or so humid and rainy that the ground is almost always muddy)? Such a society might use runners instead of wheels for ground transportation: just like some real-world societies did. Or they might come up with another answer entirely. **What about other uses of the wheel?** By some accounts, some simple machines (for example, the pulley) could be rephrased as alternative applications of the wheel. It is possible that a society of fliers might develop these without the wheel, but once they had the pulley, I can't imagine that the leap to the wheel would be very large. It might be easier to work with something similar to the Maya, as cited in another answer. Mayans knew about the wheel, but they didn't use it for transportation. Your fliers might have come to similar conclusions, depending on their situation. But the situation matters. [Answer] I think the wheel would not be invented. There is a lot of assuming that moving stuff is a requirement for a society but that may not be true in this case. Humans move stuff because it is easier than going to where the stuff is located. If flight is easy and accessible, then when you want food or shelter, you go where that is located. There is no incentive to move stuff if it is sufficiently easy to get to where the stuff already exists. ]

[Question] [ I was wondering about this... don't ask me why. GPS began in 1978. Were the specifications the same as today? Would a 1978 GPS device work today... and would a modern one have worked then? [Answer] Your limiting factor is [selective availability](http://www.gps.gov/systems/gps/modernization/sa/). Prior to the year 2000, the GPS system was considered an instrument of national security, so the signals were intentionally degraded for other than U.S. Military use. Any device could listen to the signals, but only those with the proper codes could use them effectively. There was a joke going around at the time of a grandfather and grandson going hiking in the Appalachian region. Grandfather had a topo map and a compass. Grandson had a GPS. During a break, they each took a moment to use their respective tools to fix their position. After a few minutes, the grandson announced, "According to this, we're on top of that mountain, right over there." Modern GPS accuracy can be as good as 6 ft (2 meters) and is seldom worse than 40 ft. (12 meters). Before 2000 and without the security code to SA, it was usually no better than several hundred feet/ meters. [Answer] In 1979 GPS network was "in diapers" even for military use. There were only four satellites in orbit and that didn't give enough coverage or accuracy. By then the satellite navigation system in use was TRANSIT, but you had to wait about an hour for a position or several satellite passes to increase accuracy. In those years we used radio positioning systems such as Decca Navigator or Loran-C. GPS began as a global positioning system with wide coverage (not global yet) and accurate positioning (for military) with enough satellites (10) in the mid-80s But even then, for precise positioning you needed radio positioning systems as Syledis or Trisponder (local and specific use, and you needed to set up your own network) So to answer your question: Your actual cell phone would be useless as a GPS receiver in 1979, the existing GPS network wasn't enough for accurate position everywhere. Even with military-grade GPS receivers, was of not much use then. [Answer] It's likely that you would have to wait just a few more years. As of 1979, there were only four GPS satellites in orbit. Since a 3D position fix requires four satellites in view at once, the times and places where you could get a GPS lock in 1979 would be quite limited. By the end of 1980 there were six satellites; by the end of 1983, seven; by the end of 1984, nine; and by the end of 1985, ten. In 2016 there are 31 operational satellites. I'm not good enough with the orbital mechanics to say exactly at what point there would have been four satellites above the horizon more often than not, but it seems unlikely that it would have been possible with fewer than eight satellites in orbit, a milestone that was reached in 1984. Nonetheless, geodetic receivers (meant for non-moving applications where you can collect data for a long period of time and process it afterwards) were available as early 1982. Compatibility shouldn't be a concern; the signals broadcast by the very first GPS satellites are still in use today and decoded by receivers. In the earliest years the system was a test platform, and its actual reliability unknown to me, but by 1982, with universities and government departments using it for geodetic work, you can expect that it would be somewhat reliable. You should expect lower accuracy (due to Selective Availability, fewer satellites available to compute a fix, and lack of WAAS or internet augmentation), a slower time-to-first-fix (due to lack of internet augmentation), worse indoor performance (the first flight of satellites had a lower broadcast power), and worse "urban canyon" performance (due to lack of favorable geometry with fewer satellites). Also, map applications that rely on the internet for map data would obviously be out of commission. But given favorable conditions, I would expect your time-travelling smartphone to be usable for navigation from about 1982 onwards. [Answer] L2C only became operational in 2014 so all current receivers are likely to be C/A code compatible. As well as selective availability there is a possibility that modern receivers would get confused when operating prior to the 1999 GPS Time roll-over (overflow). Poorly designed receivers might also get confused by leap seconds. [Answer] The current standard civil signal, L2C, is only broadcast from satellites launched in and after 2005. The answer is no; GPS was extant, but the signal used was restricted. EDIT: A bit of research tells me commercial products use a combination of the classic L1 signal and the civil L2C signal. Either alone would not be as accurate, however I don't know if a commercial product can use the L1 alone. [Answer] GPS reports your position (and the time) by calculating distances from at least 4 satellites. This crucially relies on knowing the positions of the satellites. As I understand it, part of the problem of a cell phone not being able to report its position when there is no network available is that it is attempting to download the latest "ephemeris", or satellite-positions information, and unable to do so. I doubt it would be possible to get the ephemeris for the satellites of the period, but if you somehow could manage it you would then have to force the phone to use that arbitrary ephemeris. (Since even if your phone could connect to the towers using whatever technology was current, and you could establish an account with a provider of the time, that provider would not yet have protocols for furnishing the needed data.) [Answer] No it wouldn't work simply because the communication and data protocols have changed many times since GPS has been introduced. You wouldn't get any signal at all because your device and satellite wouldn't be speaking the same 'language'. ]

[Question] [ A highly advanced civilization has developed and is about to ascend to become beings of pure energy in a hyper-dimensional universe. Before leaving they restore our universe to a reasonably pristine state so that new life can evolve and explore it. For the most part they remove all trace of their existence, however they want to leave something behind. This could either be out of a sense of fun (they still have practical jokers) or just to leave a signature behind to show that they existed. What sort of things could they leave behind that would be stable for millions or even billions of years, clearly the work of sentient beings, and possible to spot from a distance of many light-years. In other words it must be on at least a planetary scale. There must be no doubt at all to anyone detecting it that this is something unusual, and that it's an artificial construction. However it is a signature, not a library or anything else. It contains nothing of meaning and certainly no intelligence. This includes technology that could be salvaged (for example maintenance robots). It's just a huge "we were here" in the sky that needs to last for billions of years with no maintenance. [Answer] How about creating a large planet made purely from one element, or better yet a couple dozen from different elements each, Iron, gold, silver, carbon etc. then set them to spinning around a giant star that will eventually collapse into a black hole, between the two stages it could be many (100?) billions of years before the planets are destroyed. EDT: To go beyond a planet with exactly one element, maybe even the most singe most stable isotope as well. or maybe not? pick an isotope that can act as a clock is the planets formation? EDT2: On top of the suggestions above, having the mass of the planets being a mathematical relationship to each other and maybe to their element could add more to the monument, maybe integrate the golden ratio, pi or the Fibonacci sequence? EDT3: Could the gravity well (the "star") be made from dark matter? (do we really know that it exists?) [Answer] [Dyson spheres](http://en.wikipedia.org/wiki/Dyson_sphere) may be a good idea, since they 1: cannot form naturally using non-exotic matter (in the shell around a star form) 2: [can be detected](http://www.islandone.org/LEOBiblio/SETI1.HTM) from millions of light years away by their size and spectral signature > > The most likely habitat for such beings would be a dark object, having a size comparable with the Earth's orbit, and a surface temperature of 200 deg. to 300 deg. K. Such a dark object would be radiating as copiously as the star which is hidden inside it, but the radiation would be in the far infrared, around 10 microns wavelength. > > > If the Dyson sphere is left unmanned and only rudimentary maintenance robots are left to prevent it from collapsing, it could act as a good piece of interplanetary art. [Answer] Some unusual planetary configuration, like torus planet? Or planet orbiting two suns in orbit in shape of infinity? Pair of planet in tidal lock, sharing atmosphere? We had few of these physically possible but really unprobable planetary configurations in last few days. * [cube planet](https://worldbuilding.stackexchange.com/questions/6507/could-a-theoretical-cube-shaped-planet-have-a-moon) * [torus planet](https://worldbuilding.stackexchange.com/questions/6465/what-would-the-problems-with-consequences-of-a-torus-shaped-planet-be) * [figure 8 orbit around 2 stars](https://worldbuilding.stackexchange.com/questions/2726/can-a-planet-have-a-figure-8-type-of-orbit-around-two-separate-stars) * [tidally locked planets](https://worldbuilding.stackexchange.com/questions/4460/could-two-planets-be-tidally-locked-to-each-other-so-close-they-share-their-atmo) Or if 6-sided cube is way off from sphere and would collapse under own gravity, maybe 20-sided dice would be doable and epic. [Answer] ## Define recognizable Take look at this picture from Hubble from instance:  [Image source](https://www.spacetelescope.org/images/opo9607a/) "Eye of the God!" some will say. "Great work of nature!" say the others. And *both are (subjectively) right* For instance, our brain evolved around "uncertainty" so we tend to see "signal inside noise". Another example:  [Image source](https://blog.f1000.com/2014/09/25/seeing-jesus-in-toast-the-2014-ig-nobels/) Was it Jesus? Or is it just burned bread? Maybe the Earth is the sign (we created you to explore). Maybe the color green is the sign, because in previous version of the Universe, no such color existed. Maybe the life itself is the message. We do not know and there is no specific metric to say on purpose. And even creating something like this:  [Image source](https://creaturecomfortsblog.com/home/2014/07/07/if-youre-waiting-for-a-sign-this-is-it.html) Might get misunderstood... [Answer] These are beings of incredible power! They'd not settle for any ordinary monolith - how about a planet, solar or galactic scale *Escher* work - art that bends space time in impossible ways!  > > `http://en.wikipedia.org/wiki/File:Escher%27s_Relativity.jpg` > > > [Answer] If i was a hyper-being, with almost limitless power, and wanted to leave a sign that an intelligent civilisation had been here, i would make a "lighthouse star" - that is, something which emits radiation in a way which strongly suggests it's artificial, eg a sequence of prime numbers. I would harness the energy of something already in existence which is already pumping out huge amounts of radiation, and i would achieve the sequencing by building a dyson sphere around it with large holes cut in it, then set the sphere spinning. It's tempting to choose a quasar for this, since they are the biggest emitters - it could be visible across billions of light years. But, since they are black holes that might introduce too many engineering issues to do with stability. So, a pulsar might be a good choice - the fact that they are already emitting a pulsed signal might help draw attention to my extra layer of information. EDIT - it just occurred to me that this is kind of a cruel trick: the sign of intelligence might cause many species to launch expensive, long-lasting missions to travel to the source of the signal, hoping to meet some powerful and intelligent aliens, only to discover that they've all gone and the lighthouse is all that's left. If i was the captain of that ship i'd be pissed. [Answer] ## We apologize for the inconvenience. For those who are not familiar with the reference (*Hitchiker's Guide to the Galaxy* spoiler): > > In the Hitchiker's Guide to the Galaxy series (specifically the 4th book, *So Long and Thanks for All the Fish*), there was a planet which contained > God's Final Message to His Creation, written in giant gold letters. You could buy a post-card, but they always blurred > out the words. When you visited, you could see them, in person, larger than life: > "We apologize for the inconvenience." > > > [Answer] Klemperer rosette made up of stars <http://en.wikipedia.org/wiki/Klemperer_rosette>  [Answer] Really? For humor, but also seriously, something like this then: # A planetary sized (element/alloy of your choosing) baby fitting toy (Sorry, couldnt think of anything else after this popped in my mind)  It definetly needed highly advanced technology to be made and couldnt have happened naturally. Maybe the pieces are made from different materials. No message of significance, just a statement about how much we have to learn to be able to build something like this. Maybe the aliens have such devices, or puzzles. Perhaps the pieces can only be fitted using an specific method, not only about the correct shape. But I really like your vision about making it more like art than a test or such. [Answer] I can't stop thinking about the idea I've got from the misconception in the comments. # An artificial black dwarf A [black dwarf](http://en.wikipedia.org/wiki/Black_dwarf) is substellar object composed of everlasting electron-degenerate matter which can last for indefinite period of time and can be produced from regular white dwarf stellar remnant by artificial cooling it toward background temperature. There are no natural black dwarfs in the current Universe. Pros: * It lasts virtually forever * It remains "a wonder" for at least 1014 (1,000,000,000,000,000) years Cons: * The "sender" party has be more advanced than as per original question, achieve a substantial progress in astroengineering to cool down a white dwarf * The "recipient" party have to achieve at least orbital optical telescope stage to detect the dwarf's microlensing effect [Answer] > > And on the pedestal these words appear: > > > 'My name is Ozymandias, king of kings: > > > Look on my works, ye Mighty, and despair!' > > > Nothing beside remains. > > > The issue that I struggle with here is the stability over time..I get the feeling it'd be easier to find it in mathematics or something to that extent, but by the way you've written the question, it almost seems like you're wanting people to look out a spaceship window and see it. When it comes to it, anything that exists on a planetary scale is eventually going to be reorganized by gravity as you extend the time line into the billions of years. Art is ultimately beauty in the eye of the beholder. I've seen mention that a dog differentiates smells. They will smell peas, carrots, potatoes, meats, water, flour, and butters...we smell the full stew (can a dog appreciate the stew?). In artwork, you can stare at the individual brushstrokes, or you can appreciate the full painting. Following these lines, perhaps a series of spinning nuetron stars that produce background xray radiation thats relatively meaningless on its own becomes a song when listened to together. Though thats hard as over a billion year time scale, these eventually rearrange...but song left in background radiation that can only be heard/appreciated when taken as a symphony not individual 'sounds' would be one way of leaving this timeless. Perhaps it can be found in the really massive...2 super massive black holes oribiting each other in a binary method at the center of the universe who's combined momentum is truly 0 for eternity. Perfection is a way of conveying intelligence afterall, however it's easy for any of this not to be interpreted correctly. Perhaps it can be found as a hidden message in time...In the Planck epoch of the big bang (between 0 and 10^-43 seconds), the particles suddenly rearrange to flip us off. Maybe we've seen it just haven't care to notice it. 1-8-1, the configuration of protons in water, is their symbol for joy? Or we can get to silly…A higgs boson particle has a smiley face drawn on it? Edit: If you are looking for something a ship could accidentally stumble upon, it would be (theoretically) possible to have a location where the interference of background radiation with itself produces a 'song' to be heard. A single pinpoint (or reoccurring pinpoints) where background radiation from all directions uniquely combines to create something in it's interference...gives it something that cannot be found in the parts, only in the appreciated whole (which is a common place within art). Would definitely give that awe and disbelief feeling you are looking for, whether or not they attribute it to that race of ascending beings is hard to tell...and probably quite disputable. Starting to feel like a 'proof of the existance of god' style question...everywhere yet no where. [Answer] How about a nebula that when viewed from certain angles resembles an impossible cube? That would be quite unmistakably the work of intelligent species, and, a nice joke as well.  [Answer] A perfectly spherical planet as the only object orbiting a sun in a perfect circular orbit. The planet being made of one, and only one pure element. No moons, asteroids, or other trash or solar system debris - just the sun and the perfectly spherical, single element planet. It should last quite some time before other objects enter it, and the majority of them should pass through without impacting the planet. The perfection in the planet and orbit, and the utter lack of other solar system objects (except those small ones captured over billions of years) should set off alarm bells for any new organism sensing the planet. [Answer] I know this isn't to the massive scale as some answers, but, wouldn't rearranging mountain ranges qualify...think Nazca Lines on a huge scale. (We can't read them...but it's obvious they were written by somebody to somebody in orbit) I mean, putting them in some non-random pattern, maybe, of uncommon materials. Something that is OBVIOUSLY non-normal and not within the expected parameters of the planet -- the reader might not get the message or the joke, but, it's been left as a message [Answer] Hmm. How about a [nebula](http://en.wikipedia.org/wiki/Nebula)? Pavel Janicek mentioned it briefly in his answer, but I want to elaborate on it a little. You have a bunch of choices if you want to pick a nebula: * **[Dark nebula](http://en.wikipedia.org/wiki/Dark_nebula):** As you can imagine, dark nebulae are - well, dark! They block light from objects behind them. They're made of dust particles. A dark nebula in itself wouldn't look like artowrk, but you could use it to blot out select regions of the sky, letting only certain light sources through. You don't have to create any light, only block the light you don't want! [Here's](https://upload.wikimedia.org/wikipedia/commons/b/b8/The_Dark_Cloud_Lupus_4.jpg) a picture of one, Lupus 4:  * **[Emission nebula](http://en.wikipedia.org/wiki/Emission_nebula):** An emission nebula - guess what - emits light. A typical emission nebula is a cloud of gas filled with ions. The source of the cloud may be [a star throwing off its outer layers](http://en.wikipedia.org/wiki/Planetary_nebula), or a place where [stars are born](http://en.wikipedia.org/wiki/H_II_region). In both scenarios, hot gas - or stars inside, but typically gas - emits light. [Here's](https://upload.wikimedia.org/wikipedia/commons/1/13/M57_The_Ring_Nebula.JPG) the Ring Nebula, my favorite:  * **[Reflection nebula](http://en.wikipedia.org/wiki/Reflection_nebula):** A reflection nebula reflects the light of nearby stars or other light sources. Like the other types of nebulae, they span interstellar space and may contain many stars. You need a central source of light. [Here's](https://upload.wikimedia.org/wikipedia/commons/3/32/Reflection.nebula.arp.750pix.jpg) the Witch Head Nebula:  Create any of these and you're going to have some pretty nice artwork. But to make any watchers know that they're artificial, make sure that they follow patterns that Nature alone could not produce. [Answer] The problem with this is that whatever the signature is, a new civilization will consider it to be normal. It is like if I grew up always being told that 2+2=5, I would consider this normal. Or, how would we know if Earth has a moon because an ancient civilization put it there? That said, the best kind of sign would likely be a direct statement. Maybe they have technology to predict the language that will grow in the new civilization. Otherwise, you could use a picture, since they are not as likely to be misunderstood as part of nature and more likely to be understood as what the picture represents. This is similar to cave drawings--we don't interpret them as natural phenomenon; rather, we interpret them as drawings. *But we still consider them to be **normal**.* ``` \ | __ | o o o o | ( ) | | (__) (O) O O / | * ``` (sorry for bad ASCII art) But something like this would likely be interpreted as (comment if you know what it is before looking, I would like to see how obvious it is)... > > The solar system > > > So there's a starting point, we can tell them we know about the solar system. You might use that to tell a time, say, the last time the planets lined up in a certain way or something. [Answer] Why stop at a mere planetary scale? If these beings are truly all powerful, perhaps they can retroactively construct an entire multiverse that acts out all possible permutations of experience purely to prove the entirety of what was possible. Such an art piece would encompass all possible art and would be a fitting legacy (pre-gacy?) for a species that has truly transcended reality. The only trouble would be whether the inhabitants would actually notice and appreciate the magnitude of the art while caught up in being it. If not, it might be more of a cruel joke. [Answer] A few billion years is about the lifespan of a decent-sized star so we can do something interesting with that. However, a lot can happen in that time, so let's make sure we're thorough. We pick out 16 bright stars, all within 32 light years of each other. If necessary, we, near-ascended beings that we are, can always shuffle a few stars closer to each other to make the construction more obvious. Once we've figured out our little star cluster, it's time to build ourselves some artificial celestial objects. They don't really have to be much in terms of materials, though preferably we'll use a less valuable material so the beings that come after don't strip-mine our piece of modern space-art. As for building materials, we should probably strip the local space for this: empty out the kuyper belt, scavenge the gas-giants and asteroid belt, make sure the orbits around this planet are nice and clear. Fuse the whole lot together to something fairly simple and not terribly dense. Carbon is probably fine. Then we'll push our newly produced celestial objects into a trajectory around our stars, in pairs of two (redundancy, you see). We calculate our orbits so the planets eclipse the star at regular patterns. The first two stars get a fairly heavy dose of newly created planets, such that, as long as you're looking at the star from the ecliptical, half of the time, it's obscured or dimmed by the passing planets. I imagine the timing for this to be in the scale of a few months. The second set of stars gets a similar treatment, but with only half the material, ensuring it's clearly visible 3/4ths of the time and obscured the other quarter of the time. Apply the same process to the rest of the stars, halving the amount of time they're obscured each time. If desired, you may switch materials between steps, increasing in density as you go, to further prove the point. Voila. You've now built an 8-bit incrementing counter at a celestial scale. Sure, it rolls over every 256 cycles, but any civilisation advanced enough to build a proper telescope is going to see your piece of galactic art and think "huh, that doesn't seem terribly natural" If you want too, you can leave a snarky message on the artificial planets for bonus points, but I don't think that's neccesary. [Answer] In Arthur C Clarke's "Space Odyssey" series an unknown race of advanced beings left a series of monoliths. These were not immediately apparent but were discovered as the human civilisation advanced. These monoliths played a role in advancing the human civilisation, but in your story you could have them as just "easter eggs" for future civilisations to find. <http://en.wikipedia.org/wiki/Monolith_%28Space_Odyssey%29> [Answer] Why does it have to be huge to be visible to intelligent beings? I like Carl Sagan's idea in "Contact" where PI is calculated to millions of decimal places. Eventually the numbers become a series of 0s and 1s that form a perfect circle. This would be true eternally. [Answer] In *Strata* from Terry Pratchett, a 24000 km flat disk world, complete with mechanically animated celestial sphere is planted in our universe (something like the Earth as it was seen in medieval age, i.e. flat, and you could actually fall off if you came too close from the edge). Also some peoples make jokes like planting dinosaurs fossils wearing wristwatches, or holding a "No to nuclear power" signs. If I was doing it, I'd plant a huge perfectly black monolith (something like the 2001 one, but bigger) with on the middle of one of its faces a small push button and a "Do not press" sign. ]

[Question] [ Every species I'm aware of on earth has two sexes (with the possible exception of species which change their sexes to allow [self fertilization](http://www.britannica.com/EBchecked/topic/533390/self-fertilization)). Is it possible for a species to evolve which could have more than two sexes? How would such a race be competitive against species which only required two beings to meet and form a partnership? **I've edited** this question to use the word sex rather than gender as I'm looking for biologically based answers and wasn't aware of the distinction some answers have clarified. [Answer] Technically yes. All that genders need to do (functionally) is to get 46 chromosomes into the egg to enable it to be a full creature. Likely aliens would have a different number of chromosomes than 46. 46 isn't divisible by three, or four, so it doesn't make as much sense. Likely there would be something like 138 chromosomes, with chromosomes forming in triplets. However, the more creatures it takes to mate, the more difficult it would be for it to keep a leg up. Social scandals would be bigger, and more easily made known (three tongues to tell the tale, not two). They would also be less easily able to recover after an incident that removes much of the species. They would also reproduce more slowly especially if "monogamy" (more like "di" or "tri"-gamy) was still practiced. But this alone wouldn't doom the species to fail, other factors would probably contribute more. [Answer] It is not only possible, apparently it actually [exists on earth.](http://www.sciencedirect.com/science/article/pii/S016953470300315X) The abstract of the linked article reads: > > Two recently discovered cases of genetic caste determination in social insects might provide the first example of a major evolutionary transition from two to more than two sexes. I argue here that the system can be interpreted as comprising primarily individuals requiring gametes from three parental types and having four sexes from the perspective of demographic extinction. Additionally, I show how this mating system can be seen as a major evolutionary transition. For these populations, it is apparent that the mechanism for a three- or four-sex system does not lie within the myriad of possible arrangements of chromosomes within individuals, but at the next level of evolutionary complexity, with the arrangement of chromosomes among individuals within a social system. > > > [Answer] There are several ways on which species can reproduce sexually with more than two sexes. These are the simplest (and there are way others). ## Option a: X/Y system with YY sex (two individuals) Human system of [sexual chromosomes X and Y](http://en.wikipedia.org/wiki/XY_sex-determination_system) giving XX and XY (which is similar for other species like birds, which use [ZW and ZZ](http://en.wikipedia.org/wiki/ZW_sex-determination_system)) can be extended to three sex determinations XX, XY and YY. In this system there would be three sexes, which all can engage in sexual intercourse with each other. I'll not describe sexual organs! This has two suboptions: ## Option a1 Each individual can have sexual intercourse with every other individual, including same-sex. This implies there is no definite "female" sex that lays eggs or can be pregnant. * XX - XX gives only XX descendence * XX - XY gives 50% XX descendence and 50% XY descendence * XX - YY gives only XY descendence * XY - XY gives 25% XX descendence, 50% XY descendence, 25% YY descendence * XY - YY gives 50% XY descendence, 50% YY descendence * YY - YY gives only YY descendence Idea can be that eggs with haploid configurations mix with each other in water like frog eggs do with frog sperm. Also something more elaborate with internal fecundation (which I again do not describe). ## Option a2 Each individual can have sexual intercourse only with different sex individuals. This yields the same table as above, but with three options removed: * XX - XY gives 50% XX descendence and 50% XY descendence * XX - YY gives only XY descendence * XY - YY gives 50% XY descendence, 50% YY descendence Ideas for fertilization can be more elaborate, especially for internal one, but still there is no "female" sex. ## Option b: X/Y/Z system (two individuals) Human system of X and Y giving XX and XY can be extended to a third chromosome type Z, giving (in principle) options XX, XY, XZ, YY, YZ, ZZ. Then these need to be assigned to three sexes, or rule that some of them are impossible (e.g. YY is impossible for humans). There are so many subtions that I will not explore them all. Some are: ## Option b1 XX is female, XY and XZ are two different types of male. Females have sexual intercourse with males of the two types (I do not rule out homosexual relations, it is simply that they are not interesting for breeding). Each relation can give offspring of female or same male type of the father. ## Option b2 XX, YY, and ZZ are three types of female, and XY, XZ and YZ are three types of male. All types of male can have sexual intercourse with all types of female. Offspring have the same chromosome as the mother and one of those from the father, which means that it may be different from them both (e.g. XX female and YZ male yield an XY male or XZ male). ## Option c: Triploid system (three individuals) In these systems the chromosomes come in triplets, not in pairs. This can happen with only one type of sexual chromosome, X, [which can be present or not](http://en.wikipedia.org/wiki/X0_sex-determination_system) in the gametes, giving XXX for females, XX0 for "half-females" and X00 for males (000 being impossible). Or it can happen with two types of sexual chromosomes, X and Y, for which options XXX, XXY, XYY and YYY must be assigned to different sexes (or ruled impossible). Or even more complicated settings. Please read this answer in conjuntion with that of Monty Wild. His gives an evolutionary view about how this could have happened. [Answer] On Earth, most species that are capable of sexual reproduction have two complete copies of their genetic material (diploid), one set from each of their parents. There are exceptions (mainly in plants) where there are a larger, even number of copies (4 - quadruploid or 6 - hexaploid). Some have three copies (triploid), however, since our form of sexual reproduction involves (at its most basic level) taking half of the copies of genetic material into each reproductive cell (which becomes haploid, containing one copy of the genetic material), the question as to how the process of meiosis deals with a choice of three copies rather than an even number of copies results in errors that make sexual reproduction non-viable. However, in an alien system of sexual reproduction, individuals could be triploid or have higher ploidy, while each sex cell is haploid (or perhaps diploid or having higher ploidy but less than the normal ploidy by at least 2). In order to re-establish the correct ploidy, there may be a situation where an A-Egg and a B-Sperm combine to form an AB-Egg, which is then fertilized by a C-sperm, and becomes a viable embryo at that point. Such as system would require three types of gamete, and could result in three distinct genders, all three of which would be required to reproduce. there are possibilities involving higher numbers of genders, but the likelihood and additional advantage of that becomes steadily lower as the number of genders increases. This could arise even though it is not necessarily the most efficient way of introducing genetic diversity through the expedient of adequacy. Evolution is not actually "survival of the fittest", but "survival of the adequate". If such a system evolved, it may require too great a step backwards to asexuality in order to change the number of genders. Since a 3-gendered system would be better than asexuality, if it evolved first, there is every chance that it would not change to a 2-gendered system unless 2-gendered competition arose and outperformed the 3-gendered species. [Answer] It is possible, but it's also highly unlikely. Sexual reproduction is an excellent mechanism for spreading successful mutations through the population and allowing it to adapt to changing conditions. The rapid shifts it allows helps massively in resisting parasites and diseases. However all the benefits of sexual reproduction are immediately found as soon as you have two parents. Including more parents into the mix does not add any further advantages, however it does complicate the mating process. More effort is needed to bring three individuals in the right combination than is needed to bring two together. It's noticeable that throughout nature you have everything from plants, to insects, to animals and two genders is what everything settles down to. The only exceptions are species which have non-breeding members (such as bees) but there the non-breeders contribute to the success of the overall colony and aren't involved in breeding at all. You could very feasibly have a species with two genders, or with fluid gender, but there would need to be something very strange in the environment that gives an advantage before more got involved. One possibility might be something like the [Flouwen](http://en.wikipedia.org/wiki/Rocheworld#Flouwen) There they don't have separate genders at all, instead they gather in groups and each split off a section of themselves. The split sections merge and then a new individual emerges already knowing some of what the parent Flouwen put into it (they can speak, swim, hunt, etc immediately) but needing to learn other things. [Answer] Two sexes is the most likely pattern because math favors it. If two organisms are searching for each other, the most efficient pattern is to have one remain stationary and the other motile. If the mutual goal is reproduction, then it's obvious that the stationary partner can devote the conserved resources towards the creation of the future offspring while the motile one is better off using resources to produces a lot of seekers. The stationary partner becomes the egg and the female while the motile partner become sperm and male. But there are a few plants on earth that have three sexes. It has to do with the details of their chromosome formation and they're all insect pollinated. I don't remember the details but they did evolve out original two or dual sex plants. Still just two sexes is the simplest and therefore likely the first to evolve. You'd have to come up with a plausible selection pressure that shape a species into going through all the extra work of evolving three or more sexes. The more powerful effect would not be the number of biological sexes but rather morphism, i.e. how different the sexes are. Humans are a rather strongly sexually dimorphic species. Human males and females are readily distinguishable by size and body shape. Dogs and cats by contrast are not. You can't be sure of the sex of a dog or cat without checking their genitals. Behavior and thus social interactions would follow morphism. Humans have always had a strong division of labor between males and females but in monomorphic species like wolves, there is little to none. All wolves hunt and male and females lead but more pack leaders are females. It's likely that increasing human skull size made pregnancy increasingly difficult in turn causing women to devote more of their body to the process while having to sacrifice other functions. Certainly in the apes and in the human fossil record, division of labor increase with skull size. So, even if you had a species with a dozen sexes, if they had little division of labor between sexes and therefore were monomorphic, then all the sexes would be interchangeable for anything not related to their reproductive function (as in dogs and and cats.) On the other hand, the greater the division of labor, then the dimorphism could be very extreme with lots of different social roles. [Answer] I'm surprised no-one has already mentioned Iain M Banks's [Player of Games](http://en.wikipedia.org/wiki/The_Player_of_Games) which includes an alien species with three sexes: > > The Azadians have three sexes: Males with testes and penis, an > intermediate ("Apex") sex with a reversible vagina and ovum, and a > female sex with uterus and a retrovirus that slightly modifies the > implanted egg. > > > Quoted from <http://tvtropes.org/pmwiki/pmwiki.php/Literature/ThePlayerOfGames> The mechanism here is biologically plausible though as others have pointed out whether such a species would actually evolve naturally is perhaps unlikely and it is possible the inherent complexity would cause such a species to die out before it reached an advanced stage. In the book this is explored in somewhat more detail. He describes an alien society in which the middle sex (the apexes) are dominant with the females treated as possessions/slaves and males having limited status. See this [Google Books search result](http://books.google.com/books?id=GsCT8lPbYFMC&pg=PT46&lpg=PT46&dq=dominant+sex+in+player+of+games&source=bl&ots=hcfL0hA699&sig=YtiT8Gsm3SNGdMXbU-1B2LIvng8&hl=en&sa=X&ei=FGJbVLHmCc2iyATTroDoAw&ved=0CCAQ6AEwAA#v=onepage&q=dominant%20sex%20in%20player%20of%20games&f=false) for the passage which describes it from the perspective of an outside observer. Of course he describes various exceptions to this during the narrative but that sums up the general status quo encountered by the main character. The other thing to consider is that while such a species might not evolve naturally but a sufficiently advanced species might choose to introduce new sexes or have the ability to change between them. This might be done via genetic manipulation or via nano-technology. Again Iain M. Bank's [The Culture](http://en.wikipedia.org/wiki/The_Culture) who are the main feature of many of his science fiction novels (including the aforementioned Player of Games) have only two sexes but the ability to change between them at will: > > Citizens of the Culture refer to a normal human as "human-basic" and > the vast majority opt for significant enhancements: severed limbs grow > back, sexual physiology can be voluntarily changed from male to female > and back (though the process itself takes time) > > > From <http://en.wikipedia.org/wiki/The_Culture#Physiology> So in a sufficiently far future/advanced alien species setting you could explain the existent of additional sexes via technological means if you wished to do so. [Answer] While I'm too late to be considered for the prize, I thought I'd provide an answer anyways. In addition to the tendency to latch onto the human experience as the norm for discussion of multi-sex species, or even as the norm for discussion of sex in general (more on that anon), there seems to be an underlying assumption that, if a species has 3 sexes, all three have to contribute to produce a child, and the situation just gets worse as the number of sexes increases. Sorry, but no. First, I recommend Olivia Judson's "Dr. Tatiana's Sex Advice to All Creation". It's an excellent overview of the evolutionary biology of sex. Now. About sex. Sex is the mixing of genetic material for the purpose of reproduction. Recreational activities are not germane. The division of a species into two sexes has obvious advantages, as Tim B pointed out, but it has a big disadvantage: generally speaking, half the population is off-limits. There is no obvious reason why differentiation cannot occur to provide sexes A,B and C, where A can mate with either B or C, and B with C as well. In this case, each sex has an increased number of potential partners. It's sort of like Woody Allen's old joke that being bisexual doubles your chances of a date on Friday night. Judson suggests that the question should be "Why are there only 2 sexes?" with the underlying understanding that it seems improbable. Certainly the evolution of multiple sexes in a species with very low population density (such as specialized deep-sea scavengers) seems a possibility, since it would make finding an appropriate partner easier. There exists a fungus, for instance, with 28,000 sexes (<http://botit.botany.wisc.edu/toms_fungi/feb2000.html>), and a slime mold with 700 sexes is known, along with a protozoan with 7 sexes (<http://en.wikipedia.org/wiki/Tetrahymena#T._thermophila:_a_model_organism_in_experimental_biology>). But overall, yes, 2 seems to be the norm. Why that is, is not obvious, despite claims to the contrary. Apparently, as with so much of evolution, it's just what happens to work best. Now. As to humans. Talking about sex in purely human terms is hopelessly parochial, not to mention speciesist. Even at a fairly basic functional level, we are hardly suitable as the gold standard. Among other things, we are specialized as k-selection strategy types (small number of offspring) with no mating season and high sociability. We are apparently mostly fairly monogamous, as evidenced by relative testicle size, and recently accumulating genetic evidence suggests that, among mammals and birds, monogamy is one of the rarest practices to be found. As a matter of fact, there are a number of species in which having multiple partners increases fertility in the female. [Answer] Actually, human ADN comes from 3 sources: - Haploid male cell (sperm) - Haploid female cell (egg) - Mitochondrion ADN The mitochondria is usually seen as mother's material, but it's not. We twist the complex reality to fit the traditional thinking "1 mother + 1 father" [Answer] Depends how you define things. For more than 2 parents contributing 3 different categories of genetic material to offspring? Even here, it's no. But three sexual partners are needed. > > In a recently discovered hybrid system within the harvester ant genus > Pogonomyrmex, queens must mate with two types of males to produce both > reproductive individuals and workers. These ants are the > first species known which truly has more than two sexes—with colonies > effectively having three parents— argues Joel Parker of the University > of Lausanne, Switzerland. > > > [Answer] This reminds me of [this comic](http://www.therobinhead.com/gender-roles/). More seriously, the human race being only "two genders" is [pretty big misconception](https://www.youtube.com/watch?v=xXAoG8vAyzI). Here's the "genderbread" person shown there for reference:  You have sex, gender identity, gender roles, sexual orientation, romantic orientation, sexual behaviour, etc - all of which are traits that people try to squeeze into that concept called gender, but it's really just a fuzzly box that sorta describes most people. But there's always exceptions - intersex, trans\*, genderqueer, and neuter people being a few. And I think there's tons of story potential in tweaking any one of these in a fictional world. More specifically on the topic of worldbuilding, [here's](http://en.wikipedia.org/wiki/Single-gender_world) a list of some stories made tweaking gender norms in worlds (having only males or females, everyone being both male and female, extreme segregation, etc.) that might help for inspiration. Just remember, as a fantastic writer told me: "With any world it's usually best explained through the readers discovering the world through a character, because that's how we as humans think." It's admittedly kinda weird to do in some of these contexts though, but still interesting I think (though I'm trans\* so I'm probably biased in seeing a lot of the pain that our current gender norms in society puts me and other trans\* people through). As some more ideas: Imagine a society where equivalent "western" culture was more like some [Native American tribes](http://en.wikipedia.org/wiki/Two-Spirit) in being supportive of gender-variant individuals, and even seeing them as fulfilling an essential part of their society in some way (say as healears or special role players in the sun dance). That kind of thing could probably be carried over to a modern society in some way I suspect. Maybe some kind of government position, or probably more reasonably just no cultural barriers against LGBT issues and coming out or anything was never relevant because it was never seen as abnormal, or something like that? Or imagine a society where most people are intersex, maybe even to the point where if someone was "too male" or "too female" (though those terms probably wouldn't be used there) they'd be considered as having a "disorder of sexual development" and require surgery to be more "normal" by becoming what we see as intersex, [similar](http://en.wikipedia.org/wiki/Intersex_surgery) to often how intersex people are treated today. Of course there's also the option of having a society where gender-lines are very very rigidly defined but I feel that would probably be less interesting because our society's been like that in the past in some ways, unless it was either a backdrop to something more significant that was unrelated, or so severe that it was shocking to us. Personally I've always thought it would be fun to write some kind of story from the perspective of a member of a hive-mind society (think sorta bees but more extreme) where gender isn't really even relevant because being an individual isn't even relevant, and everyone is sorta attached to a whole. Or making a world where everyone sees gender more like that alien does: Simply something that's a part of someone, just like being a chef or scientist. [Answer] In Octavia Butler's brilliant *Xenogenesis* Trilogy, the alien species *Oankali* have three sexes, all necessary for reproduction: for the male and female sexes the intercourse is impossible without "the third" sex, the *ooloi*. Their culture prides itself on being "non-hierarchical", in contrast to humanity which they consider destructively backward due to its hierarchical model. Here is a brief [review](http://www.tor.com/2009/09/30/octavia-butler-re-read-dawn/), giving a good idea of how Butler presents this culture. Spoiler: it's far from idyllic. [Answer] To extend from the multiple types of answers already given, you might consider dipping into Judith Butler's profoundly influential book *Gender Trouble*. In this book, she makes a remarkable argument about the now-common distinction between "gender" and "sex." In short: the usual view (post-second-wave feminism) is that "gender" is a cultural or individual or whatever choice or interpretation or representation that is or is not directly correlated with an underlying biological substrate; and "sex" is the biological substrate, divided into two. Butler argues that, in a large number of ways, the claims and assumptions about the biological absolute duality of sex are problematic. As several answers and comments have already noted, there is extant evidence of sex not being necessarily dual. For example, if we grant that "male" includes several distinct expressions of chromosomal material, yet we accept that these are all "the same thing" because they all come out functionally "male" with penises and whatnot, then we're imposing a preconception of binarism on what we know about the biological substrate. Conversely, when we encounter examples in which material is expressed in a very unusual way, we label these "abnormal" and therefore insignificant -- thereby reaffirming our preconception that there are only two sexes. If that's the case, then the claimed absolute link between "sex" and objectively-existing biological substrate is ideological, in which case the difference between "sex" and "gender" is that "gender" is required culturally to bind itself to the absolute dominance of "sex" because of the power of the cultural presupposition of binary sex. Which is to say, "sex" and "gender" differ principally on the basis of who's got the power. I am not saying that Butler is necessarily entirely right or wrong about any of this, but reading her work may jolt you into dramatically different ways of thinking about your question and the results you're trying to get in your worldbuilding project. [Answer] As a further wrench into the works, consider that in many species, the breeding unit is not the pair, but the pack/herd/swarm. Wolves: When the pack is at carrying capacity (in balance with their food supply) then often only the alpha female and alpha male mate. Depending on the usual prey, the pack may include siblings, cousins, nephews, uncles of the breeding pair. The entire pack raises the pups. If food is plentiful, more breeding takes place. If food is scarce, the female may not come into heat, or will produce smaller litters. Bees. 1 queen, usually 1 drone, everone else helps. (Note: There are ways to trick domestic bees into having multple queens in the hive. This is economically useful for ramping up colony populations fast to meet peak blooming time, without having to make more hives. Herds. Usually 1 dominant male, sometimes a few. Sometimes 2 tiers of breeders -- Dominant male covers most of the females, secondary males cover 1 or a few each. In terms of a sentient species, you may get the biological equivalent of Greek Phaetry <http://www.oxfordreference.com/view/10.1093/oi/authority.20110803100324887> <http://www.oxfordreference.com/view/10.1093/oi/authority.20110803100324887> or of the warrior societies of North American aboriginals. From the point of a selfish gene, if you don't breed, you better help the ones who share your genes to do so. [Answer] I love the concept of the triploid sexual system. I first saw a third sex suggested in Alien Nation, though I wonder whether it was fully triploid, or if the third sex was merely a catalyst. A catalytic third sex might arise in the case of a species that is too reproductive, causing famine or war. Triploid reproduction could evolve as a mutation, with the third sex being originally unnecessary. The third sex injects its DNA into a fertilized diploid egg. The resulting embryo has advantages and a chance to be of the third sex. In time, further mutations cause the egg to be infertile without both kinds of sperm. The lower reproductive rate might not be disastrous and might even allow for a more stable population as medicine extends the lifespan. Triploid reproduction could even begin through genetic manipulation, as a method of birth control. The third gender might initially be rare and under government control. Broken genes inserted that can only survive with all three parts. Perhaps the third gender only graces the most productive, healthy and intelligent of the generation, making sure that they produce more heavily. [Answer] I'm surprised no one has mentioned Larry Niven's Pierson's Puppeteers, which have three Genders involved in reproduction. I say gender as only two of the beings involved contribute genetic material, so strictly speaking this is straightforward two sexes reproduction. However, it does add an interesting twist to reproduction, where a third party must be involved. The third gender is a non-sentient being who is parasitised by the puppeteers, with both sperm and an ovum deposited in its body. In puppeteer society, when a couple get permission to breed, they go and pick out a host together. This method of reproduction was one of the Puppeteers closely guarded secrets, as they rightly guessed it would alienate other sentient races. A narrative description of the process is described in the novel series *Fleet of Worlds*, *Juggler of Worlds*, *Destroyer of Worlds* and *Betrayer of Worlds*, although I'm afraid I don't recall which book the details feature in. [Answer] The OP makes it clear that he's referring to sex, and not gender, so let's leave all discussion of gender to one side. Sexual reproduction supercharges evolution. it allows the assortment of genetic materials from two individuals to produce the genome of a third, new, individual, thus ensuring that there are new genes (produced by mutation) and new assortments of genes, produced by meiosis, to face the environment in new ways. But why TWO sexes? The answer is not culturally determined. The answer does not depend on sociology or (other forms of) fiction. It depends on the chemistry of DNA, which forms the double helix we all know and love, thereby making itself stronger and more resistant to random change during life. Let's represent a diploid strand as AA' in one individual, and BB' in a second. These separate into A - A' and B - B' at meiosis. When they combine, they can recombine as AB, A'B, AB', A'B': so where before there were 2 genotypes, there are now 4, and it may be that the new combinations are more advantageous for survival than the old. This is how evolution works. As long as DNA chemistry works this way, this is the way things have to be. Two strands, 2 individuals to contribute their shares. Nature is prolific and ingenious, so at higher levels of organization (and by *higher* I mean only higher in an organizational sense), all sorts of arrangements to bring this mechanism about are possible. Some of these arrrangements are more likely in physical, chemical, biological or environmental terms than others, and it seems that the two-sex arrangement has particularly high survival value, for it is omnipresent. Let's refer to these as *supra-sexual* arrangements. Among these survival arrangements is the universal presence of mitochondria in animal cells. Nitochondria are not a third sex. They are originally parasitic microorganisms that became symbiotic in animal cells, giving energy in exchange for protection and transport. This arrangment was obviously highly beneficial. Mitochondria carry their own genes. Eukaryotes produce motile sperm cells and sessile ova. Sperm cells are basically stripped-down packages containg a haploid genome, and little else. Ova contain the genome, in a fully-functioning cell, which contains mitochondria. When this cell is fertilized,, each time thereafter that cell division occurs, each new cell contains about half of the mitochondria of the parent cell, and these mitochondria then reproduce asexually *within the cell*. So in the adult organism, all the mitochondria are descendants of the originals in the ovum that gave rise to all those cells, which is why we can trace mitochondrial lineages through the mother, but not through the father. In the case of the queen ant cited above, she no doubt requires fertilization by two individuals to produce two types of offspring because these two individuals have slightly different genomes. This is a neat demonstration of a supra-sexual arrangement. Another such supra-sexual arrangement might be the rich bachelor uncle who sets up his nephew in a house of his own so he can get married. This has high survival value, which is why it is common in all human groups. In English we call this *nepotism*. [Answer] Two sexes are familiar: individuals who each undergo meiotic cell division and combine their partial genomes. An individual might be male or female or switch back and forth but the essence is meiosis and combination of 2 individuals. One individual might undergo meiotic cell division and combine two such of its own cells. This is still sex in that the meiosis is the key piece of sex - it still shuffles the genomic deck and offers the possibility for improvement over the parent. Many plants are hermaphrodites capable of self fertilization. The last is asexual reproduction: no meiosis, no shuffle, just regular mitosis keeping genome intact and a clone of the parent. Good if your parent is good. Things use asexual reproduction to maximize the population of an organism that is doing well in a given environment - like that aquarium strain of the seaweed Caulerpa that has given up on sex and is one big clone. Sex is helpful if circumstances are not ideal. Some organisms do mitosis and asexual reproduction when the living is easy and then fall back on sex in hard times. ]

[Question] [ So let's say you live in a terrifying post-apocalyptic world. For whatever reason, this world is now infested with cockroaches the size of chickens (similar to radroaches from the Fallout games, but ignore the radiation). My question, then, is would it be better for a chicken farmer to keep on raising chickens, or switch to roach farming? Assume the roaches are the same mass as the chickens, but otherwise very similar to ordinary cockroaches. Also assume that the chickens and the roaches would be fed the same food. What I want to know is which one would be most cost-efficient for calories per dollar of feed? If it's implausible to consider such large cockroaches, you could alternately answer based on a collection of cockroaches adding up to the same mass. [Answer] ## [Cockroach Farming](http://www.cbsnews.com/news/cockroach-farming-a-booming-business-in-china/) is the future! They feed the roaches wheat shavings and vegetables for four months. Then they're boiled, dried and some are crushed to put into pill form, which is much easier to stomach. Cockroaches are omnivorous scavengers and will consume any organic food source available to them. Although they prefer sweets, meats and starches, they are also known to consume other items such as hair, books and decaying matter. Cockroaches eat what is available to them: cockroaches that inhabit sewers feed on sewage, while species living on dead trees consume decaying wood. When left with no water, cockroaches can live days to a week. When given water but deprived of food, some cockroaches can survive for months at a time. ## But can we eat these? Insects have a fat body. It’s a versatile organ, a sort of combination of adipose tissue (the blubber that humans have) and liver. Its principal roles are: * As with adipose tissue, it is the main nutrient storage site * Storage of neutralised waste metabolites; Detoxification of ammonia from protein metabolism * Control of nutrient levels in the haemolymph (“bloodstream”) * An immunity organ, producing antimicrobial peptides in response to bacterial or fungal intrusion into the haemolymph * In females, producing vitellogenin, the precursor to egg yolk and thus critical for reproduction ## So we get Fat and Calcium from these things in large amount, let's look deeper into the milk The cockroach in question is the only type of roach known to give birth to live young, the Hissing Cockroach, which is also the largest insect, and it produces a sort of milk to feed its babies. The study's researchers, of the Institute of Stem Cell Biology and Regenerative Medicine in India, [discovered a protein crystals](http://journals.iucr.org/m/issues/2016/04/00/jt5013/) in this stuff that actually contains more energy than the same amount of cow's milk. "The crystals are like a complete food — they have proteins, fats, and sugars," one of the study's main authors, Sanchari Banerjee, told the Times of India. "They can be a fantastic protein supplement," added Subramanian Ramaswamy, the leader of the project. Since undernourishment and hunger still plague much of the world, developing a more calorie- and nutrient-dense alternative to milk could be a major improvement to many people's diets. ## So we got information on the milk, but what amount their bodies "It sounds weird, but insects can definitely be good for you because they're a good source of protein and they're low in calories," says Keri Gans author of [The Small Change Diet Healthier](https://www.amazon.ca/The-Small-Change-Diet-Healthier/dp/B0058M64GO?tag=vglnk-ca-c84-20). It helps to compare insects to other well-known sources of protein, like chicken and eggs. So here we go: A typical serving size of cockroaches is 5.8 ounces. That portion contains 21 grams of protein and 176 calories, says Gans. In comparison, that same amount of eggs (about two large eggs) contains the 13 grams of protein and slightly less calories (154). That same amount of chicken contains 31 grams of protein and about 200 calories. "That makes sense, though, because chicken is one of the biggest sources of protein around," says Gans. --- And there is your answer, chicken meat is more efficient than cockroach meat which is better than eggs. Their milk is much more beneficial than cows milk, so due to their size when compared to an combination of cows and chickens as well as their adaptable diet I'd say Cockroaches are the fututre! [](https://i.stack.imgur.com/ELU54.png) [Answer] # Both Really. My answer will be subjective, because I "reenacted" postapo trader in a postapo world few times. So I have *some* experience. ## Both are edible As perfectly explained by another answer I've already upvoted. Both are also relatively easy to farm. And both are tasty. They really are, once you give it a try! ## There is no food worse than boring food If you live for few days on scrambled eggs and chicken meat, deep fried roach is some very welcome diversity. If you try to eat dried nutrients, you start to crave something *normal*. If you work for 12-16h / day, you need protein. And so on. ## Safety from disease If bird flu kills all your chicken, you have roaches. And vice versa. Much less risk of losing it all. ## Leftover disposal Cannibalism is not healthy for your animals. But by feeding chicken leftovers (fresh!) to roaches, and roaches to chickens, you increase your risk only marginally, and save quite a lot of organic matter. [Answer] Insects in general are more efficient as a source of protein than most animals, but generally we don't eat insects because of cultural bias. As well, given the large size disparities, catching and eating insects during the Ancestor's hunter gatherer stage was a losing proposition (for the most part, it takes more energy to catch and eat insects than you get from actually eating them. Nesting social insects are an exception to the rule), so we preferentially look for larger animals for our protein. Cockroach or insect farmers in general will have to carefully disguise what they are selling, or sell to a different market. You would certainly recoil at the thought of roach burgers or deep fried grasshopper, but might not think too much about the white powdery organic protein supplement you add to a drink or soup mix. IF it is already "cooked into" processed foods, you aren't going to think much about it either. Even more directly, as a high energy supplement for body builders or as an otherwise unidentifiable "protein bar" in an MRE or survival supplement, most people will just crunch in. The other part of the market is selling insect protein as food supplement for animals. Feeding it to chickens, hogs, cattle or even as fish food provides a high density/high energy meal for the animals, and helps get them ready for market. So your farmer might like the idea of farming roaches (supersize or not) because they are easy to care for and he can get a "crop" in with a very short turn around time, but he will have to be careful *how* he is selling it. [Answer] Roaches, like spiders and mantids are subject to being infested with parasites, in example they can be infested by Nematomorpha: [](https://i.stack.imgur.com/5ql9W.jpg) It is full of videos on youtube of insects (roaches included) infested by worms. I guess that if "scale size" keeps on, so that if roaches gets bigger also their parasites get bigger, then you will have something serious to deal with, because when you kill roaches for turning them into food, you will have a pretty big worm going out of them, and this is definitely a thing that you have to care about when breeding roaches because thos worms could be, not only a health issue, but also a safety issue (are giant Nematomorpha dangerous for humans?). Actually they would become bigger that most commons snakes, and since they are pretty fast (compared to their size), they could be quite hard to catch and could go anywhere causing damages of any type. A regular worm can be meters long, a chicken is somewhat 50 times bigger than a roach, so if a roach is big as a chicken its infesting worm can be as long as 50 meters. Weird.. yuck! [Answer] If your world defines the problem as being infested with cockroaches the size of chickens, people believe there are already too many cockroaches. Presumably supply is too high to justify farming them for profit. If you farm them, there also could be problems with sales, with 'wild' cockroaches passed off as 'cultivated.' You could have a farmer who agrees to cut back oversupply (like plowing under during the Great Depression in the US) to access subsidies, and uses ground roach as feed for chickens. On the other hand, if cockroaches are a market, breeding slightly larger chickens as transportation might work. [Answer] I would recommend roaches - with their more diverse diet a farmer has many more resources available as feed for his farm. And as I believe roaches can eat almost anything you could find inventive ways to feed them (non-harmful) waste product or refuse. As always it comes down to cost: which livestock would be most economical to manage? ]

[Question] [ It's unclear what happened. Perhaps there was a nuclear apocalypse, the one event for which the Swiss (with their 100% nuclear shelter population coverage) are uniquely prepared. But that comes with nuclear winter and other side-effects I don't want to worry about. So let's go ahead and simply assume that everyone else got Raptured, or kidnapped by Aliens. Besides Switzerland, the world is empty. **Could Switzerland survive and thrive as a modern technological civilization**? As of 2014, they had a population of 8,211,700, quite well educated, but unclear whether they can maintain a technological civilization on their own. Can they? **EDIT**: Let's assume that the physical infrastructure in the rest of the world is left in place, subject to weathering and whatever other degradation the lack of human supervision and maintenance would likely cause. [Answer] **There is a possibility of survival after incredible suffering** Contrary to other opinion the Swiss are in a precarious position if the rest of the world goes away. Here are several major issues. * **Power Production** The majority of their power is imported. This could be curbed by making the use of air conditioning in the Summer illegal and forcing the Swiss to rely on public transportation primarily. Perhaps doctors and other private individuals of stature could be allowed a fuel allowance. The Swiss have a zero regarding petroleum. They have zero identified oil reserves in the ground. They do very well with natural gas production and this could be leveraged long term. The real issue goes back to crude production. The Swiss have a good refinery infrastructure but no drilling. They consume 86,870,000 barrels of oil produced goods per year. **Thats 4,777,850,000 gallons of oil used to make the products that the Swiss consume per year!!** That means no; tires for cars, plastic containers, plastic product shells, plastic baggies, solvents for fixing/cleaning cars, solvents for almost all forms of manufacturing, lubrication for hydroelectric generators, rubbing alcohol for medical, ALL medical plastic goods like hoses and syringes, toothpaste, shampoo, soap, eye glasses, roofing material, wood preservatives, glycerine, coolant, ink, grease and the list goes on and on and on and on. Shortages of many of these goods will lead to a reduced quality of life and health issues which will lead to death for some as this dystopian reality moves through time. * **Manufacturing** is an issue. Not because they need TV's but because they need to keep their hydroelectric infrastructure in order. The metals required for creating turbines, chips and most any device that is smaller than the 1960's version will require rare earth metals. Those are mostly in China and Africa so they are off the table. Without the ability to repair their digital power grid and keep their hydroelectric power production up, they will be in the dark with limited power. 2% of total electric production in Switzerland is from solar, which also requires, you guessed it, rare earth metals, which we have already established, they have none of. **A way to solve this problem** could be to force all residents to turn in there high end electronic devices from iPhones to big screen TV's in order to recycle any rare earth metals within them to maintain the countries power grid. At the end of the day the Swiss reliance on 100% import of petroleum will have their manufacturing grind to a halt. This is a major problem. * **Agriculture**, some seem to think, for some reason, that the Swiss have some great agriculture infrastructure. This is not true. Most countries with a small land mass that are highly developed begin to depreciate their agricultural infrastructure over time. Especially when it's cheeper to buy it than to grow it. If there is one thing about the Swiss where they stand above the world, it's there economic view almost everything. If they can buy their lettuce from Frances vast agricultural infrastructure (the French have a lot of land) then those farmers will who grow lettuce will start growing product they can profit from. Most of the basics for protein are imported. Fish, poultry, pork and beef are not a strong point of the Swiss. Nor are potatoes, corn, wheat and most fruit. This is a major problem and the Swiss **would undergo a period of starvation** until they figured this one out, which they probably would in one or two growing seasons. In the meantime there will be suffering and the overall health of the population will suffer. * **Medical**. Modern medicine requires manufacturing and because of the lack of petroleum this will be a challenge. No power, no resuscitation. No power, no health monitors, no CAT scans, no brain wave monitoring, no automated pulse monitoring. Petroleum based soaps and iodine based soaps for disinfectants will become a thing of the past and very quickly. Medicine will devolve into a 1920's remedy driven industry with severe shortages of anti-biotics, pain killers, insulin, etc. * **Pharmaceutical**. Pharmaceutical production will drop to nearly zero as petroleum products dwindle. With that goes antibiotics, sedatives for surgery (The Swiss will have surgery performed upon them without being knocked out, this is some dark ages stuff here.) Individuals relying upon a drug for their survival will not have that drug. Insulin is one that comes to mind. **People will die as a result of not having the drugs they are dependant upon to survive.** Additionally, people with simple infections will suffer a higher death rate. Individuals that require blood thinners will have a shorter life span. Individuals that require drugs to shrink their prostate will die horrible deaths as their bladders expand and burst because they are unable to discharge urine. Laxatives to plastic eyeglasses will become a commodity. * **Natural Resources**. Here is the complete list of natural resources according to the CIA World Factbook. Hydropower potential, timber and salt. That's it. That is a precarious position on a good day. The people will suffer and many will die as a result. At least in Iraq there is a strong agricultural infrastructure and production. This won't come down to anything but food. * **Water Supply**. Water will be available in reservoirs but the Swiss require a pumping infrastructure that requires petroleum fuels to operate pumps to get the water to where the people are. Due to the topography of Switzerland water must go up and down terrain that is difficult. Petroleum is the fuel necessary get the water to the locations where it can have an impact on the populace. Thinking that water will not be primary issues under the circumstances you enumerate is a non-starter. Water availability will be what drives personal health and well being of the population and without refined diesel in this case the water will be stuck in reservoirs. In order to fulfil the demand people will migrate to the water. This is happening already in central Asia and the results are horrific. As migratory populations seak water for survival the individuals will form groups for protection and these groups will clash over water. Additionally, as parts of the populace migrate to water their own fecal and urinary waste will begin to contaminate it. The results are almost always the same, E Coli, forms of salmonella, giardia and a [slew of other water born illnesses](http://azdhs.gov/preparedness/epidemiology-disease-control/waterborne/index.php#list) will come into play increasing the death rate of water seekers as they contaminate the water they have found inadvertently. **Eventually a portion of the population will survive** Under extreme duress and lack of commodity consumables like medicine, food and water the society will begin to break down and governance will be an afterthought. Communication with the populace from the government will become more and more difficult. As the population seeks out other industrialized nations infrastructure they will encounter the same issues abroad in neighboring countries, a lack of petroleum products to restart manufacturing, lack of potable water, food crisis and all assortment of survival issues associated with a dystopian world crisis. The 8 million people that will require basic staples such as rice and wheat will begin to seek food for survival from their neighbors. Government control will break down and the military will be unable to prevent looting and other fear driven group behavior. Neighbors will die as groups seek to build power to control limited resources. The Swiss do not have a lot working in their favor. Other countries have a more favorable outlook especially if they have a method of mass protein creation as with cattle, poultry and pork. Wheat or rice production in a country is very favorable. France is much more well suited for this sort of situation but most of the above would still apply to them. **Where the Swiss will fail** * Potable Water * Grain Production A portion of the population will survive but the likelihood of a large portion of the population surviving is very low. Even with outside help in today's world populations suffer great duress. The Swiss will have themselves and their very modern world will work against them as this infrastructure requires a global economy to endure the crisis. Precious metals in manufacturing, petroleum for water pumping and lubrication of hydroelectric generators, shortages of pharmaceuticals and potable water contamination will lead to millions of deaths and great suffering for those unlucky enough to survive. [Answer] Short answer: **Yes** Long answer: **Yes**, *Easily*. Switzerland has considerable reserves in case of worldwide non-swiss rapture (or because if their neighbours decide to screw them they've got no other alternatives), so they're OK in the short term. However: They don't produce all of their own power (they make roughly 50% of it) and they don't produce all their own food (importing roughly 45% of it). Oh no, this is an issue! Except it isn't. Now you've got a resourceful people with a large stockpile of materials and some generation capacity of their own in an unparalleled position to expand outwards into the unsullied fertile fields and pre-developed industrial spaces of their former neighbours. Not only that but they've got enough in the way of rifles and military supplies to immediately mobilise exploitation, hunting or resupply parties to restart critical foreign power infrastructure/get more food. The Swiss are golden in this new world! In terms of brain drain: They still have access to a lot of information, and there's a large enough population to ensure that things, skills and knowledge that need to be preserved will be. Eventually New Switzerland will be a peaceful utopia where everyone's clocks run in perfect time. [Answer] ## Outlook: very, very good The main question here is how much damage society takes while adapting to the new situation. In other words, how long can people keep things running while ensuring continued availability of important high-tech goods? Switzerland, especially with its surroundings in place, is in a good position for agriculture. Also, the Swiss are peaceful, educated, and endorse federalism; it seems rather unlikely that they'll start a war about the rest of the world right away. This leaves two main concerns: * Energy: Switzerland is heavily dependent on imported fossil fuels. * Maintaining technology: The world's industrial production is down and critical demand needs to be filled before certain goods become a bottleneck. Since the rest of the world is still there, getting energy simply means grabbing the deserted refineries and means of transportation that *are still there*. This is too easy; with barely over one in a thousand people still there, the available and often still functional power sources are gigantic. The ability to produce all technology again will take time, but there's *a lot of it still present* that will be grabbed and used. Until that runs out, the Swiss economy will adapt to focus on the most important things. Being a very modern and free economy, I couldn't think of a country better suited to this adaptation than Switzerland. There will be a time of low availability of some goods, but overall, I don't see any major obstacles. *Note that current technology is spending a lot on advancement that could be spent on survival. Producing any half-baked version of past products is sufficient to keep things running, and doesn't require the huge amounts of research, development, marketing, and so forth that current competition requires. You don't need a 32", color-perfect, above-HD display to do daily work. Nor do you need to travel around by plane at every whim, or eat imported luxury foods, or heat every room in every building to summer temperatures. If space, resources, and mad dictators are out of the equation, survival isn't that hard.* [Answer] I think the answers above are missing one crucial point: You state that nearly all people on earth dissappeared but that the physical infrastructure remained "intact". The problem with that are all the nuclear power plants, that are left unattended. After a very short period without maintenance, the poor swiss will see funky explosions all around their mountainous haven. [](https://i.stack.imgur.com/TWrgc.gif) Even if only some of them blow up, the living conditions in Europe will be not suitable for a restart of the civilization. [Answer] * Natural resources: luckily Switzerland is the home of a number of the world's leading commodity companies (Glencore, Trafigura). So the expertise is there to know where all the stuff is, how to get it out of the ground, and how to transport it. * Power: most of the country is run on hydro and nuclear. Should be fine even with a slight decrease due to missing shipments. * Tech knowledge: still got ETH and EPFL, highly regarded technical universities. * Economics: highly integrated with Europe and the world, with lots of people living near a border, it would cause big problems. Anything import or export related, which is just about everything, would be affected. A lot of people would need to find something new to do. * Food: The biggest danger is dying from heart disease. Without foreign food, all that's left is rosti, fondue, and sausages. Foreign chefs will become celebrities. Farmers will know where the best land is. * Government: The country is already governed by local democracies. Different communities can respond in their own ways to the new normal. [Answer] You don't say who exactly was taken. Are Swiss people outside of Switzerland spared? Are people inside Switzerland who aren't Swiss spared? So the people outside of Switzerland suddenly disappear, what will happen. Well the first thing is there will be a load of "accidents". Cars that have lost their drivers while travelling at high speed are going to end up in pileups blocking up the highways. Airplanes are going to fall out of the sky sooner or later (sooner if there is no autopilot, later if there is one). Lots of industrial processes may also fail in nasty ways. Generally when assessing risk "every human suddenly disappeared" is not a reasonable risk. Railways typically use "dead mans switch" type controls and trains are fairly widely separated. So the railways will be less badly obstructed than the roads. A road-rail truck will likely be able to navigate the railways fairly easily but there aren't enough of those around to move more than a handful of people. Getting actual trains through will require doing something about the empty trains and doing something to take control of the points. IMO with large number of accidents and no firefighters fire is likely to be a big problem. Especially if it happens during a hot dry summer. With no humans to maintain it I would expect the power grid across Europe to start going into emergency modes and dropping loads off pretty quickly until it collapses completely. I am not a power engineer so I don't know how quickly it will go down but I would be very surprised if it was still operational by a few days after the initial event. The Swiss may be able to disconnect their grid from the rest of Europe but if they do then they would probably have to put in place a harsh level of rationing. The internet will likely start disappearing a day or two after the power grid does as each datacenter runs out of fuel for it's backup generators. Also lots of people just disappeared in a way science cannot explain. If the rapture is based on nationality then lots of people will see this happening. If it was based on location than less people will see it directly but the combination of a few people seeing it directly and many more people seeing the indirect results is going to lead to news spreading. That is going to strike fear into peoples hearts. You have Switzerland which appears to be safe or relatively safe and the land outside where everyone just suddenly disappeared. With no idea what the hell just happened I would expect people to be very reluctant to venture outside of Switzerland. Eventually a shortage of food and parts will force the Swiss to send people outside Switzerland to scout for resources. Likely at least some places will have avoided the fires and will have stocks of canned food that can be plundered. I think severe technological regression is inevitable. Yes stuff is written down but often the devil is in the details and the details often only exist in people's heads. The supply chain for high tech products is complex and tangled around the world. Another problem will be fuel degrading. Petrol that has been stored too long just doesn't work right in engines. I'm not sure if diesel fares better. Likely some people will survive but their society will likely look nothing like ours. [Answer] In the short term, they're fine. Things would be pretty great. Starvation wouldn't be a problem -- just the canned goods left in supermarkets across Europe & Asia would probably be over a year's worth of food for the Swiss They'd resettle resource-rich areas, starting with those near Switzerland. Getting to key resources like petroleum & food wouldn't be hard with cars, trains, motorcycles, planes, etc. now free on practically every street corner The Swiss new world colonizers would find fortunes worth of food, oil, art, technology & pharmaceuticals. Their only survival risk would actually be themselves. Some of them would also find tanks & nerve gas & even H-bombs. That's the danger: If even a relatively few Swiss became lawless warlords and started gathering up abandoned weapons systems, things could get pretty bad & crazy after all So all in all, I'd say they'd probably be able to do really well, but there would also be a chance that some maniac would find an unattended missile silo and ruin everybody's day [Answer] **No government, only warlords** First things first. As soon as Swiss army realizes what just happened, they dispatch units to secure the world's nuclear weapons. From the military point of view this is absolutely top importance. Naturally they start with surveying French locations. But something very strange begins to happen along the way with strict hierarchy of military commanders. Colonels and majors that lead these missions walked on a predefined narrow career paths for all their lives. As they see all the empty world, they begin to realize more and more *possibilities*; they have their own *ideas*; their desires wake up. Should they give all the enormous world's wealth and all the power to those moronic generals back home? Several units return from France de facto as nuclear-armed warbands. Having nukes, now they need population to scavenge goods for them. So they kindly request Swiss government to yield all the power to them. After a couple nuclear mushrooms appear here and there, the government steps down; but most of the Swiss people get their own ideas too. They all get the idea that sitting in Switzerland means they could be soon either nuked or enslaved; and anyway more people here = less food, less oil. So mass migration starts, the first wave with small aircraft, the second with cars, the third on bikes, the fourth-and by far largest-on foot. The warbands get their small share of population and resources and go off to secure the remaining world's nukes. Naturally now with a lot of empty land, without very large cities, and with all those overheated nuclear plants' cores starting to pop up everywhere, the nuclear war is no longer taboo. The warbands start to nuke each other on a small scale. So people spread throughout whats left of Europe and Asia, in groups of 50-100. They don't have to manufacture or grow anything, they live on all the stocks left for years and years. There is no motivation to get together into any peaceful townships, so the warbands are the only forms of "polities" left in existence. After century or two the whole mess develops into feudalism; some more centuries and there is hope that technical civilization will somehow return. But not the industrial revolution. This path is closed. There is no more easily available hydrocarbons, which were in fact accumulated energy of billions of years of sunlight. I don't know how this civilization would transform later. Medicine and biotechnology maybe?... [Answer] Yes, they can. It will look exactly like this: [www.instagram.com/dietegen](https://www.instagram.com/dietegen) The energy and food problem of nuclear winter will be solved with biodiesel production in the crematoriums. The weakness of infrastructures is solved by small armed groups. Modern means of communication can be maintained through sponsorship. A crypto currency is the only means of payment. It can be earned through armed service like in the old times of Swiss mercenary. Communication structures are maintained for this reason. Online, there is a certain choice of goods for soldiers and widows. All in all: a low standard of living and a high civilization level are not absolutely incompatible. [Answer] No. Things would be fine for a while but their 8 million population simply isn't enough to maintain a high tech civilization and in time things will run down. The problem is one of specialization. There are a lot of things that society does that are represented by far less than 1 per 8 million people. Those things will pretty much cease to exist. The Swiss will survive but not at a 21st century tech level. [Answer] Some relevant facts about Switzerland: * World's [second most](http://atlas.cid.harvard.edu/countries/41) complex economy. * World's richest "proper" country in terms of GDP per capita (the others are all either tax havens, city-states, or oil-based economies). * With 8M people, produces half as much [elite level science](https://www.natureindex.com/country-outputs/generate/All/global/All/score) as Japan, with a population of 127M. * Produces a significant share of the world's machine tools, which constitute the essential base of industrial economies. * Has a high level of social cohesion. There will almost certainly not be warbands wandering off and establishing their own fiefdoms, at least within the first decades. Electricity needs will be met in the short to medium term with its hydro and nuclear power plants. Obviously, there'll be some initial rationing in such a scenario, as with food and fuel. But given the extreme nature of this scenario and their internal discipline the Swiss will accept that. Renewables and nuclear account for something like 70% of Swiss electricity production, not like the world is going to collapse (further) with a 30% shortfall. Fuel shouldn't be the constraint that many people think it is. Consider that many EU countries need to keep oil reserves at a level equivalent to around 3 months of consumption. Just looting Germany's would easily let them maintain consumption at current levels for several years to come. This will easily be enough time for them to take over the world's most productive oil wells. With fuel, food is hardly going to be a problem either. Again, they can loot strategic grain reserves in other countries. There'll be a vast surfeit of livestock; the first couple of years they can gorge on meat uninterruptedly. In a few years, once existing reserves are run down, they can establish farms in the world's most agriculturally productive areas with Swiss efficiency. There'll obviously be some problems. A country with 0.1% of the world's population obviously won't be able to maintain anywhere close to its current range of industrial capabilities and technological knowhow. Nonetheless, as a very innovative and high IQ nation, they should do a very respectable job of that. With massive land endowments per capita, it's quite possible that fertility rates will go above replacement rates and the Swiss population will crawl up to the tens of millions in a century after the disaster. At that point, a resumption of absolute technological growth may even be possible, given its very high human capital. ]

[Question] [ It's the Great War, and all the nations are having a good time of it, painting their biplanes flashy colours, as they shoot into their own propellers! But over in the corner, lonesome and dejected, the centaur nations had no planes at all.... They can't fly anywhere, they don't get to put on goggles or get set on fire while simultaneously suffocating. They just sit sadly in the corner. As they get ready to charge tanks with lances, they pause to stare up, wistfully, at the thunderous air-battle between knights of the sky. That was... until YOU came along to make them a fighter plane! --- Could a centaur nation, with WW1 tech build a fighter plane which a centaur could pilot? If that's too much to ask, you can reach into WW2 levels of tech. So, there are a few points to consider. 1. Can you build a fighter plane for a centaur? 2. Would it have any unique characteristics, compared to human fighter planes? 3. Would there be any advantages or drawbacks to centaur pilots compared to human ones? I've written an example answer, if the metrics are unclear *(since I have been badgered extensively about strange metrics, of late)*. [Answer] You definitely could. However, I have thought of a few additional concerns: **How do you strap in?:** Human pilots preferentially sit in a chair, and can easily be belted in. How do you strap in a centaur? Do they have to straddle some kind of saddle, and then tie in straps over their back? Can they strap themselves in, or do they need someone else to do so? **Plane Control:** Human pilots use their feet to control the rudder. If a centaur is standing, they cannot use their feet in such a manner. If strapped in properly, they potentially have 4 feet to control with, or 2 more than a human pilot. This allows another axis of control - perhaps they can fly with just their legs, and use their arms for a gunner control? **G forces:** You mention that they may be better at handling G forces, and that is a possibility, but G forces will have a very different effect on a centaur as opposed to a human. Think of a tight upwards loop - the human pilot is in a nice reclining position, and most of their blood stays in place. For a centaur, this same maneuver would cause all of the blood to pool in the "horse portion", resulting in a complete blackout at a much lower G force. [Answer] Yes, it would be possible to build a plane that a centaur could fly using WWI technology, but the centaurs would still be at a severe disadvantage because they would need to build very big and non-maneuverable planes to accommodate their larger and heavier bodies. Now, WWI was the first war where actual air-battles took place and where aircraft played a major role. Before WWI, the only aircraft that militaries employed were observation balloons, the occasional zeppelin/blimp, and a handful of spotter's planes. Powered aerodynamic flight was still in its infancy--in fact, at the beginning of WWI, air-battles were so primitive that they consisted of pilots flying around in their planes with a pistol in one hand and the plane's yoke in the other, trying to shoot the other pilots or a critical component of their extremely lightweight aircraft. For example, one of the most famous planes in WWI, the [German *Fokker Eindecker* massed in at 400kg empty and 610kg full](https://en.wikipedia.org/wiki/Fokker_Eindecker_fighters#Specifications_(E.III)). This plane had one pilot and an integrated, propeller-synchronized, machine gun along with a flight time of roughly 1.5 hours. Comparably a *single horse* can easily mass in anywhere between 450-1000kg, which is heavier than that plane, pilot, ammunition, and fuel combined. A scaled-up plane would work from an engineering perspective but would require longer runways, more materials, and be more expensive. In my opinion, for centaurs, plane technology simply isn't advanced enough in WWI to make building fighters worthwhile unless there are Shetland-centaurs or they're willing to train child-soldiers into being pilots--if they need planes, their fighter-equivalent would be the size of a human's bomber. Still, that doesn't mean that the centaurs can't take to the skies. If they instead focus on high-altitude zeppelins, blimps, and balloons, they may be able to play to their advantages against humans or humanoid races: * Centaurs have a much higher lung capacity than humans. This means that they can operate at higher altitudes without requiring compressed air tanks. * Centaurs are naturally more equipped for dealing with the cold. A centaur has the thermal mass along with the fur to withstand the cold temperatures at high altitudes easier than a human--no matter in how many layers they bundle up. * Centaurs have more natural strength compared to a human. Normally, this doesn't matter as an airplane can't be powered by 1hp, but an already buoyant blimp could be powered by a centaur-bicycle system. * Centaurs have more limbs than humans. Although it would probably require training, a single centaur could probably pilot a plane with their hooves while manning a gun with their hands. [Answer] **They actually existed** Below is a picture and specifications of a [Centaur 2A, built in 1919](https://www.google.co.uk/search?sxsrf=ALeKk00aowq0fnHss2SQF4SN-KSxNvB5aQ%3A1610023245082&source=hp&ei=TQH3X4-8AurIgwebn4zoCA&q=Centaur+2A+1919&oq=Centaur+2A+1919&gs_lcp=CgZwc3ktYWIQDDIECCMQJ1CyFFiyFGDOLmgAcAB4AIABRogBRpIBATGYAQCgAQKgAQGqAQdnd3Mtd2l6&sclient=psy-ab&ved=0ahUKEwjPluf864nuAhVq5OAKHZsPA40Q4dUDCAk). The photo doesn't show the centaur pilot. I'll see if I can find one. *Edit - Found! diagram added at end* Note that the centaur's head and shoulders stuck out of the fuselage where you can see a dip near the front in the picture. It would look like an ordinary pilot was flying. The horse body was totally concealed within the fuselage. It was tricky to get in. I'll see if I can find a picture of that. There won't be any videos from the time. [](https://i.stack.imgur.com/X70F3.png) [](https://i.stack.imgur.com/nLkxL.png) [](https://i.stack.imgur.com/ktK6v.png) [Answer] Why would you need an engine when the pilot is an engine with a peak power of about 15 hp? Thats right. Although we call it horsepower, a horse has about 15 hp (peak performance). So going into another direction than retrofitting a plane which was designed for weak humans, we could design a plane that uses the centaurs muscle energy to create lift. I'm thinking about a glider with a bike-like mechanism to power a prop. Considering that your centaurs might be technologically behind other races, that would fit well. There is also the advantage that you don't have to build a complex engine for each plane. You just need some wings and gears. Centaurs would have a huge numerical advantage. [](https://i.stack.imgur.com/LOhqa.jpg) [Answer] Don't let the neighsayers and badgers keep you from your dreams of flight. Have you ever thought about a... [](https://i.stack.imgur.com/PmH4E.png) ## Flintstones Plane You read that right. I attached a picture of the Flintstones car above for reference, should you happen to not have watched that cartoon before. My proposal is for the bottom of the plane to have four portholes for the centaurs to stick their legs out of. I'm leaning on the trope of centaurs being faster runners with much more stamina. The idea is that the centaur can use its leg power to perform a kind of assisted takeoff with reduced ground run distance required, or conversely use its legs to help bleed off speed when landing and come to a shorter stop. Considering the burden of additional weight a centaur would place on an aircraft from the 1910s, this might be needed to break even with a non-centaur plane and not actually be a comparative advantage. [Answer] ## Starting from point 3 As far as I can work out, there'd no benefit to having a centaur pilot as opposed to a human one. Their physical strength and speed are no advantage to them, but rather are detriments. ### But... then again Though... maybe you could extrapolate some advantage in that centaurs/horses have larger lungs and bigger hearts (and possibly two hearts), and so might handle G forces and high altitudes better? They would have an easier time staying warmer, being a larger creature with some fur. So, thinner pilot jacket, less discomfort and clothing to handle the cold. That would only be a minor benefit. ### Cultural benefit Hunters had good records as pilots, with many of the flying aces having been hunters. So the culture of hunting and marksmanship associated with centaurs might make them better shots and fighters on average... if their plane is still manoeuvrable enough that they had a fighting chance, that is. Regardless of their effectiveness, I imagine national pride would lead to experimental centaur fighters, who may be used in a war. If their results were good, they might make more. ## Plane Characteristics Let's move onto how the plane characteristics might be effected. ### Size and weight A centaur is long, tall, and heavy. Maybe they can lean forward, the equivalent of a horse reaching its neck forward, to reduce their height... but that does increase the length issue. This could necessitate a larger plane. Though if you removed the copilot, they might fit into the plane by lying down, and it wouldn't need to be much bigger? That could be helpful, so that it's a fighter plane instead of a small bomber. ### Parachutes It may not be practical to give centaurs parachutes, since quickly exiting the craft and the expense of producing such a large parachute may be prohibitive. On the bright side, parachutes weren't that common through WW1. Planes were flying low enough that it was a dubious proposition for a fighter pilot. I do wonder if you could produce parachutes for centaurs at that point in history. ### Plane Characteristics Those things together, the plane might have a very large passenger compartment, filling the position of the pilot and copilot. Anything important in the plane between those points will have to be moved elsewhere, which may mean a larger plane. If the added weight of a centaur (anything from 900lbs to 2,000lbs) was an issue, they might need a more powerful engine, which could make the plane a fuel guzzler. If those things are true, then a larger, heavier plane with more powerful engines could make for a unique fighter design. You might even exaggerate it by adding additional armour or engines? Potentially, it could be that centaurs don't build pure fighters, but instead building something more like a fighter-bomber. ### Tactics If you can make an air-doctrine which can emphasize the strengths of greater armour, power, and maybe firepower, then this could help subvert the weaknesses of the centaur. They probably have a history of Mongol-style tactics, so they might be skilled at bombing runs or even feigned retreats. With more powerful engines, you may be able to outrun enemy fighters, although mobility is likely not great, compared to the Steppe ponies of the Mongols. You may have to compare them more to the heavy horse charge of knights, where in this case instead of lances they would use M2 Browning .50 Calibre machine guns, with a heavy enough plane and pilot that you DON'T want to be playing chicken when they dive in your direction. ## Can you build it? I can only guess at this, as I lack the data to approximate how difficult an extra half ton of weight is for WW1 planes. But, towards the end of the Great war... I think it's possible. By WW2, you certainly have fighter-bombers, and they were being developed at the end of the war. [Answer] I want to highlight the opposite approach to IronEagle rather than leave it as a comment. The safest posture for your Centaurs in a plan is to be laying down. This avoids having to stand when pulling Gs providing the same benefit as sitting for a human pilot. This does obviously mean they'll be restricted to hand controls only. So your Centaur is going to have to cope with doing different things with each hand to give them the extra control interface that a human pilot gets from their feet. Similar to the way a Helicopter pilot has an extra plane to control by hand (assuming I understand Helicopter controls, which is not a given). A horse weighs roughly 8 times what a human does, so you'd have more difficulty with older planes where weight was a major issue. The next problem as you move towards more modern planes is ejector mechanisms. You don't want your Centaurs to have to ride their craft down in a blaze of glory each time there's a problem, so replacing the functions of the ejector seat in a modern fighter or the "bail over the side" strategy of an older model will need some consideration. How does a Centaur use a parachute? [Answer] Being half-humans, centaurs really can drive planes: arms for the steering wheel, front legs for the pedals. And as you mentioned, there is an additional benefit having two more legs so they can be used for something good (extra flight controls, actuation of machineguns and cannons...). Counter-side: horses are 3-5 times heavier thus we need more "horse power" at the engine. Also, it's harder to board/unboard a pilot to the plane (via belly-mounted ramp? or via a crane device?). Finally, having a bigger body, the pilot is more exposed for being wounded by the enemy fire. All after all, centaurs are more likely to be bomber pilots, or any other essentially big planes where a pilot weight is not that noticeable compared with entire "takeoff weight". [Answer] A lot has been covered in other answers, so I just want to add two specific points to consider: 1. Because centaurs are so much more massive, it will take a few years longer to develop the first planes that can carry them as pilots. A centaur-only world wouldn't invent planes as soon because it's a harder problem for bigger passengers and pilots. 2. I think it would be harder, not easier, for them to handle G-forces. Because they are much more massive, the [square-cube law](https://en.wikipedia.org/wiki/Square%E2%80%93cube_law) makes them generally more fragile under their own weight. Also, they would need a cradle supporting their ribcage, and more of their weight would be pressing down on their lungs. This would become more of an issue as they entered the jet fighter era, and eventually it might be enough to keep them from being competitive as fighter pilots. Edit added to emphasize the square-cube law: Muscle and bone strength is proportional to cross-sectional area. Centaurs would be strong because their muscles and bones would be larger, with greater cross-sectional area. However, the volume and mass grows faster than the cross section. If you double the dimensions of a cube, it has four times the cross-sectional area and eight times the volume. This means that centaurs would be weaker in terms of fighting Gs, because the weight pressing on their ribs would be larger per unit cross sectional area. However, you could always put in a fantasy element and assume they are made of inherently stronger materials. Maybe even give it a semi-scientific rationalization. [Answer] It (joke aside (yet not too far)) may have looked like this, allowing the centaur to step in and out easily. [](https://i.stack.imgur.com/bOGha.jpg) [](https://i.stack.imgur.com/zS9gv.jpg) [](https://i.stack.imgur.com/VW4BA.jpg) More seriously, as mentioned in other answers, centaur must have comfortable position allowing to withstand g forces, something like this could take place inside the cockpit: [](https://i.stack.imgur.com/4EzAK.jpg) ([source](https://practicalhorsemanmag.com/.image/t_share/MTQ1MTM4MzQ0ODYwMDAxNjg4/a-lift-for-broken-leg-recovery-promo-image.jpg)) [Answer] Lung capacity of a centaur might help in doing strenuous work at altitude, but there are two biophysical limits that cannot be overcome by just increasing lung capacity. Lungs are basically a semi-permeable membrane that allows gases to pass through. Oxygen moves from air to blood because the partial pressure of oxygen (ppO2) dissolved in the blood in the lungs is lower than ppO2 of the air in the lungs. Carbon dioxide moves the opposite way because its partial pressure (ppCO2) is higher in the blood than in the air, because the blood brings more CO2 into the lungs all the time. *But there is nothing to stop the gas exchange from going the other way if the partial pressures change, or to force it to happen if there is no sufficient difference of partial pressures.* There's also some water vapor, which always stays at or above certain minimum partial pressure (ppH2O) by the physiology of the lungs: if the air you breathe is drier than that, some water will come out of your blood and so you'll lose moisture on every exhalation. And finally, there's the partial pressure of nitrogen (ppN2), which is important for scuba diving, but in aviation it basically just takes up space from the important gases (unless you're flying soon after scuba diving, in which case you'll need to be careful). As altitude increases, the ambient air pressure decreases, and the partial pressures of the various components of the ambient air decrease in the same ratio. But in your lungs, the carbon dioxide and water vapor exiting the blood will keep the partial pressures of these components of air at or above a certain minimum level. Basically, when you reach the point where the sum of partial pressures of ambient nitrogen + carbon dioxide in the lungs + water vapor in the lungs equals the total pressure of ambient air, the flow of oxygen from air to blood will be completely blocked. **You can breathe all you want, but you aren't getting any oxygen in.** If there is any remaining oxygen in the blood, it will actually *escape* if the ppO2 in the air is lower than the ppO2 in the blood. This a big part of the reason why a sudden depressurization in a pressurized aircraft at altitude makes you pass out so quickly, and also why the safety instructions in passenger airplanes tell you to always put on your own oxygen mask first before helping others. (This is why mountain climbers talk about the "death zone" near the peak of Mount Everest and other tallest mountains: if you are near the top of Mount Everest and not using supplementary oxygen, you will be effectively suffering from a constant oxygen shortage because you're approaching this limit.) By using supplementary oxygen at ambient pressure, you'll effectively replace the useless nitrogen component with more oxygen, which will allow you to go higher. But once you go high enough, the sum of partial pressures of just the carbon dioxide and water vapor in the lungs (which have a minimum limit set by physiology) will equal the total pressure of the ambient air at altitude, and then you'll have the same problem again, and supplementary oxygen will no longer help. At that point, you will need either a pressurized cockpit, or a spacesuit. (Source: an aeromedical lesson that was part of glider pilot basic training.) [Answer] Why not use some other sylvan race as pilots? Centaurs usually live in sylvan forests, close to pixies and suchlike. Among them should be ideal candidates for flight. Centaurs can be ground personnel where their strength and speed will really shine. Imagine mechanics with a built in 15 HP engine for moving equipment. Some ideas: find some warlike tiny woodland creatures for use as pilots. Think Nac-mac-feegle or D&D blood-caps. They don't need to fully understand aviation, just enough to be able to fly. Races like pixies that have wings would be ideal. Centaurs can do the engineering and everything, so the pilots don't need to be able to advance tech. Imagine the centaurs seeking out the remnants of the bloodcap tribes, trying to get them to drive the planes. With both groups being at different points of civilization, and perhaps even intelligence! The human "pilot ace is the hero" culture don't have to appear, after all. There might be a more collectivist feel to it, with each team of pilot(s) for the plane and controllers/tacticians sharing name and fame. [Answer] **Alas, not in 1918. But for WWII they'd take Flying Fortress to a whole new level** So there's been some great answers here, but few seem to truly appreciate the fact that flight was NEW in WWI, and subsequently the aircraft were not great. Planes were so primitive that nobody actually knew what they were doing, even in 1918. To the point where there were no wind tunnels, and nobody would be quite sure if design would even fly until they built a full-size model and tried it. For another example, seatbelts were very specifically not a thing in WWI aircraft. Why? Because the odds of the plane catching fire (accidentally or through enemy action) were HIGHER than a pilot being thrown out of the aircraft. So in case of a crash, the 4 seconds it takes to undo a seatbelt could mean you were still in the wreck when it caught fire/blew up. So your centaur probably wouldn't bother with a seatbelt either, because plummeting to one's death is infinitely preferable to burning alive. The one advantage I can see for a centaur, larger lungs and body = better in the cold and at altitude, is not super useful in WWI aircraft. Because of the limitations of the planes themselves, climbing high enough for the centaur to put its advantages to use wasn't really a thing for most of the war. Even when planes COULD achieve that height, they didn't really know what they were doing. By that I mean "oil would freeze, guns would freeze, and generally the damn things wouldn't work because people didn't quite grasp all the ways that 10,000+ft was different than ground level!" The power to weight ratio of even the human-crewed WWI aircraft was laughable. As already pointed out most of the fighters fully loaded weighed less than your average horse. So even if you handwaved "my plane can go high enough to give a centaur the advantage in cold/oxygen" you've increased the carrying capacity of your plane such that a human pilot could throw in an oxygen tank and/or enclosed cockpit. The power-to-weight on a WWI plane was no joke. They didn't carry parachutes as standard. For the brit's, it was because they were afraid pilots would bail out instead of saving the aircraft. But for LITERALLY ALL THE OTHER NATIONS AT WAR it was allowed, and pilots still wouldn't do it. The reason most pilots wouldn't carry parachutes is because the 10kg that parachute weighed was better spent on ammo, speed, climb, or maneuverability. Unlike in WWII, where a few extra pounds was NBD, in WWI it was the difference between life and death. By WWII the science of aircraft and engine design had advanced enough that you could have centaur-piloted aircraft. But power-to-weight is still something of a problem. Centaurs would be at a supreme disadvantage in fighter design, as their craft would be necessity be bigger, less well armored, less maneuverable and likely slower than their human opponents. However given their engineering needs (have a useful aircraft with 1 or more 500+kg crewcentaurs) I think they would be VERY heavily invested in bomber aircraft. Something like a suped-up B-17 would likely be the order of the day. A big long-range heavy bomber can more easily accommodate horse-crew. They'd have to be well-trained though, as you'd need to economize crew to save weight. (For example, no copilot and merge the bombardier/navigator position, because each centaur means 1 fewer 500kg bomb carried) They'd also, due to the limitations of centaur fighter support, likely take the idea of a "Flying Fortress" to extremes unseen by human bombers. Because you can't rely on fighter escort and need to keep crew to a minimum, perhaps their bombers would forgo machinegun turrets for light flak cannon or other more dangerous weapons. They'd likely not work super well (humans after all were wildly over-confident in the ability of bombers to "always get through" the B-17 was originally envisioned to need 0 fighter cover and look how that turned out.) but perhaps some other tech innovations like proximity fuses making their bomber-born flack cannon wildly more deadly than humans would expect could give them an edge. Or maybe their quest for MORE POWER to lift their extra-large crew means they take a gamble on jet engines more readily than human nations did. So something like the British Meteor (slowed down due to budget and reliance on old-but-proven propeller-aircraft tech) gets invented by centaurs first and they have it by 1939. That'd give them the power to create fighters capable of going up against prop human aircraft. or just big strategic bombers that went fast enough they'd be untouchable by human prop-planes. The advantage would be fleeting, because when humans saw what they were doing they'd swarm over it much like how the allies reacted to the ME-262. But it'd be a fun narrative to dive in to. For more fun Great War aviation facts, I suggest "Marked for Death" by James Hamilton-Patterson and "Gunning for the Red Baron" by Leon Bennett. Be advised that, like all books on WWI, they get REAL depressing at points. [Answer] Consider if the Centaur-flying inspiration might go in a very different direction than biplanes. They're already most of the way towards having the form of a Pegasus, anyway (which perhaps also exists in the world with other fantasy races such as Centaurs?). [](https://i.stack.imgur.com/SvAsi.jpg) Instead of looking at the Centaur body as a handicap, instead see how it might be an advantage; the Centaur's long, extended, powerful body serves as a ready-made fuselage. Perhaps Centaurs are happy to have mostly glider-equipped forces. This could dispose of the usual seat that humans need, and instead just strap a set of wings to their back. Perhaps the primary usage would be as drop-troops, such that Centaurs could silently land behind enemy lines and then leverage their powerful charging ability on land to disrupt enemy forces. [](https://i.stack.imgur.com/f5ni8.jpg) Alternatively, we could go back to the start of real-world air flight when human-powered flapping-winged aircraft were the subject of experiments. While these didn't work, perhaps Centaurs with their powerful legs could have made this successful (again, with no need for a seating mechanism, but instead with faux-pegasus wings strapped to their back). [](https://i.stack.imgur.com/1aqVx.jpg) [Video at YouTube](https://youtu.be/FMyGtIyblbM?t=12) [Answer] I don't know how much centaurs weigh, so I just did all of the following using a hypothetical "average horse". I think it's funnier to think of horses flying planes anyway. So, just thought I would add some numbers to spruce things up. The common German fighter during WWI was the [Albatros](https://plane-encyclopedia.com/ww1/albatros-d-iii/). It's empty take-off weight was 659kg and its maximum take-off weight was 886. A horse often weighs somewhere in the order of 450kg (about 1000 lbs). (659 + 450 = 1109 > 886). A centaur would not be a good fit for that plane. But let's change our assumptions. Say our friendly centaur has access to the best engine at the time. While the average plane was powered by a [160hp, rotary engine](https://en.wikipedia.org/wiki/Rotary_engine), by the end of the war engines had improved to get up to [400hp](https://en.wikipedia.org/wiki/Radial_engine). So, more than twice as nice, yes? Well, let's take a look. If a 75kg (165lb) man (without any equipment) had 160hp, then he would [go about 9.6 km/minute](https://www.calculator.net/horsepower-calculator.html?force=882&forceunit=newton&distance=8&distanceunit=kilometer&time=60&timeunit=second&calctype=def&x=0&y=0#definition). With 400hp, this number goes up to 24km/minute. What about the horse though? A horse weighs about 6 times as much as a man. This means that the horse, even at some of the best engines at the time, would only get 4km/minute. Hm. That's not looking good. But I'm doing those calculations without accounting for the weight of the equipment. What happens if we include the weight of the plane? A mostly-empty Albatross, with pilot, using the best engine at the time, can do roughly 2.5 km/minute. The horse would go about 1.6 km/minute. So clearly, we're better off using humans in the skies, but what if we gave a human an old plane and the horse a new one? Well, then you're talking about the human in the 160hp plane getting to just under 1 km/minute with the horse going 1.6. If we limit the human to the engines common immediately before the start of the war (80hp), the human would go less than a third the speed of the horse. Seems like the horses might have a fighting chance. So, if you can solve for the extra strain on the structure of the plane and provide the horses with technology roughly four to five years ahead of humans, then it seems entirely possible for horses to win dog-fights. What about g-force? Well, g-force is a question of maneuverability and acceleration. A 400hp engine accelerating as fast as it could with a horse would not accelerate as fast as a human pilot, even if the horse were accelerating twice as fast. As for maneuverability, that follows the same rules. The heavier the payload the slower it can turn and, consequentially, the less g-force the pilot will experience. [Answer] I am just "putting my two cents in" here: But do you know the actor Fess Parker of the good old times tv show Daniel Boone (one of my favorite tv shows ever) was turned down by USAAF because he was too tall at 6 feet 6 inches (1.98 m)? <https://en.wikipedia.org/wiki/Fess_Parker> > > He enlisted in the U.S. Navy in the latter part of World War II,[6][7] hoping to become a pilot. He was turned down because he was too tall at 6 feet 6 inches (1.98 m). > > > In deed, Apollo project astronauts had a very strict height limitation. Not too short, not too taller. Believe me, the airplane engineers are great, but place a 2143.38 pounds, four legs plus two arms man/animal inside a cockpit is out of question in Word War One, Word War Two and Word War Three! [Answer] Ornithopter. The half-horse features would provide an average of 1HP(746). Far higher than a cyclist that gives 300w. That means you can make them excellent Commandoes! Propelling silent ornithopters that move in the night, deadly ambushes behind enemy lines! [Answer] "It's the Great War, and all the nations are having a good time of it, painting their biplanes flashy colours, as they shoot into their own propellers! But over in the corner, lonesome and dejected, the centaur nations had no planes at all.... They can't fly anywhere, they don't get to put on goggles or get set on fire while simultaneously suffocating. They just sit sadly in the corner. As they get ready to charge tanks with lances, they pause to stare up, wistfully, at the thunderous air-battle between knights of the sky." Why on *Earth* would the centaurs *want* to "get set on fire while simultaneously suffocating?" The problem here is you're taking centaurs away from their natural role and making things really, really complicated! See, centaurs are essentially cavalry, for all intents and purposes. Additionally, if centaurs so much as *exist*, one of two things must be happening: 1. Science-Someone has the tech necessary to create chimeras (creatures that incorporate cells from different species, AKA sphinxes, mermaids, centaurs, lamia, and so forth) and is doing so over and over (chimeras can't breed another one of their kind) 2. Magic-either someone used magic to combine animal and human parts to make that centaur, or someone used magic to combine a human and horse to make that centaur. I'm assuming magic, as otherwise a centaur nation is almost completely impossible (come on, how likely is it that an *entire nation* of genetically engineering chimeras exists and is being maintained by a veritable army of mad scientists?), and so the centaurs should, naturally, have magical enhancements. These enhancements likely concern strength, endurance, and speed and everything that would make life difficult for a centaur would likely have been accounted for. Additionally, if these centaurs are anywhere near as *fast* as the ones in the Percy Jackson series, they can *easily* take down a tank with the right equipment. Tank treads are really quite vulnerable; not the entire thing, mind you, but the track pins and gears are relatively unprotected, *especially* back in WW1 (which is what this sounds like). Quickly placed or thrown mines, anti-tank guns, cannons, or even a thick tree trunk stuck in the treads should break the thing and render the tank useless. A lance of the right material (mithril maybe? This *is* fantasy, right?) can just penetrate the armor and kill the pilots. In conclusion, centaurs have no reason to build planes as they'd be much more effective as "infantry" and can very well develop anti-tank and anti-plane weaponry to make up for the lack of either. ]

[Question] [ **This Query is part of the Worldbuilding [Resources Article](https://worldbuilding.stackexchange.com/questions/143606/a-list-of-worldbuilding-resources).** --- This question focuses on the initial creation of landmasses. * What are the processes that causes land-masses to form, and continents and islands to rise up from the sea and sink back into it? * How can those processes be easily drawn upon to create realistic looking maps? --- Note: > > This is part of a series of questions that tries to break down the process of creating a world from initial creation of the landmass through to erosion, weather patterns, biomes and every other related topics. Please restrict answers to this specific topic rather than branching on into other areas as other subjects will be covered by other questions. > > > These questions all assume an earth-like spherical world in orbit in the habitable band. > > > --- See the other questions in this series here : [Creating a realistic world Series](https://worldbuilding.meta.stackexchange.com/questions/2594/creating-a-realistic-world-series) [Answer] While bowlturner's answer provides a list of processes to work with, I think that, since this is about worldbuilding, there should be some technique in applying all of these possibilities in a practical way. Practical means, since we're not talking about software explicitly here, possible to do with pen & paper and fit it all in your head. *Keep in mind, the following technique is intended to give a realistic result, but it doesn't necessarily depend on absolute realism or application of mainstream theory in every step* ## Elevation Starting out with a barren rocky planet, we can apply some elevation to reduce how smooth it is, which can help later. This can be done randomly - a nice noise algorithm can help of course, but since we're on paper here, we can just divide the world into a few large sections and roll dice for the elevation at each intersection. To do this properly, we need a range of elevations that make sense. We need a mean elevation and a higher bound. We can't define the lowest elevation as sea-level since we have no sea yet. Since Mars is considered to be close enough to a young Earth, we can use its elevations at this point since there's less corrosion there (which gives us room to apply our own corrosion later). The highest and lowest points on Mars are 30km apart, the highest mountain is 22km and the mean elevation (datum surface) is at around 8km. Apply any elevation at the intersections within these bounds and adjust until you have a proper mean elevation. Then subdivide the grid and perform the process again at all new intersections. This will give a very artificial look to it, so just merge and divide peaks and valleys until it looks more reasonable. Now is the time to place craters and stuff if you have to - make sure they're big impact craters since smaller ones will erode away anyway.Decide whether to apply the surface features due to elevation over or under the craters (did the impact happen after a mountain was formed?) Craters should be large and cover a 2 digit percentage of the surface. They should also not be too deep, at most a tenth of the elevation range (in this case 3km, but less is better). If you don't want oceans in the world, you can pretty much stop here. If you want earth-like, it's time to break it up. This will give you continents. ## Seas & Continents Create fault lines around the caps and across the entire surface, more if you want lots of continents, less if you want less of them. Then, recede the surface from the fault lines - the further away land is from the faults, the larger the oceans and the deeper they will be. Feel free to reduce dry land to 30% of the surface or less. All of this doesn't need to be done with detail, just roughly. After you're done getting continents, create more fault lines all over the place. Don't recede them - these are your tectonic plates. If you're unsure about how they should look, [here's a pic](http://en.wikipedia.org/wiki/File:Plates_tect2_en.svg). From the picture it's obvious the plates neither coincide exactly with continents nor are they completely random. ## Volcanoes Now randomly place volcanoes - all over the place. The previous grid approach can work. The number of volcanoes throughout history is probably too high to work with, but it seems that today there are about 1500 potentially active ones. About 15 volcanoes should be enough because, as you can see [here](http://earth.rice.edu/mtpe/geo/geosphere/hot/volcanoes/volcanoes_map.gif), they're pretty well clustered along the tectonic plate fault lines. After randomly placing them, bias them *heavily* towards those lines. Those that are very close should be multiplied to cover large lines along the faults. There should still be a few left far from those lines however. If they are placed on dry land, they create volcanic mountains, if they're close to land but not on it, you get an island - if they're far from land, in the ocean, you get an underwater volcano. After noting the spots, their scale needs to be decided. There's the [VEI scale](http://en.wikipedia.org/wiki/Volcanic_explosivity_index) for that. The scale goes from zero to 8, where zero is relatively inert and 8 is apocalyptic. We need to make sure we've got the volcano's surroundings covered as well. The tephra would be ejected into the atmosphere and would eventually be deposited on the ground. There's also lava covering the surroundings. How far would these go? We can divide the total volume of tephra (find it out by the scale of each volcano, from the VEI) by a thickness and get an area of settled tephra for that thickness. Apply it to the surrounding area. Wind and weather would of course affect things, but we can be freeform about this since simulating weather for each eruption etc. will quickly get too tiresome for this. The magma bubbling out based on index can be seen [here](http://volcanoes.usgs.gov/images/glossary/magmavolume.jpg). You can assume that all those cubic meters turn into a large mountain. But how tall and wide does it get? We can use the right circular cone formula and solve for either height or radius to get a result - fortunately, google has us covered - search for "cone volume" and it should give you a calculator to work with, along with the formula if you need it. Obviously this is hard to do for 1.5k volcanoes, so just do some quick calculations for those that are solitary and then pick some points along the volcano lines, calculate something for those and interpolate the rest of the volcanos (so that they are larger when closer to large ones and they get smaller as they get near the small ones). If you need a thickness for the line, use the average volcano radius for that - you can also just assume the tephra is distributed in a circle and take that radius for the tephra circle line. Fuzzy it up a bit for "realism". An alternative would be to distribute the sizes based on frequencies, that you can derive from a chart like [this](http://www.coolgeography.co.uk/A-level/AQA/Year%2013/Plate%20Tectonics/Volcanoes/VEI.jpg). ## Canyons, Mountain Ranges, Island Series This is where our plates start to matter the most. Canyons and mountain ranges are easy. Look at [an example](http://www.nrdc.org/oceans/canyons/images/canyons-map.jpg) - here's a rough map of [mountain ranges](http://s.hswstatic.com/gif/maps/jpg/WOR_THEM_Mountains.jpg). It's obvious there is a fault-line relationship. Since both canyons and mountain ranges are results of plate interactions, we need to shake them to get some of these made. An easy way is to place random vectors on each tectonic plate - for each plate, make an arrow of a length and direction. They should start roughly from the center of each plate. To get the horizontal and vertical components and make our life easier, use a [calculator](http://thecraftycanvas.com/library/online-learning-tools/physics-homework-helpers/vector-calculator-component-resolver/#construct_from_components) or more easily, just draw a rectangle aligned to the grid for which the vector is its diagonal - the left and right sides are your vertical component and the up and down sides are your horizontal. Now look at where all the new arrows are pointing. If two plates are pointing to each other, make it a mountain range if they meet on land or a series of islands (can be underwater islands) if they meet at sea. If they're pointing away from each other, that's a canyon. We need to know how tall these ranges are going to be and how deep the canyones are going to be. There's two quick approaches to this - use the same range of elevations from above, from Mars (since we're going to erode mountains to 2/3rds to 1/2 later, don't use Earth ranges - highest point should be ~20km and lowest trench underwater should be ~5 km below sea level - canyons should go at most 1.5km below sea level) or move around the plates multiple times (like 3-5 times) and count collisions and retractions for each edge within the total number of movements; divide the *total* elevation with the number of iterations to know how much difference each ones makes and then do a simple addition to make out their depths and heights. All of these collisions are earthquakes - like volcanoes, if you want a rough estimate of how powerful they can be and how often they can happen (for more detail) take a look at [this](http://www.seismo.ethz.ch/eq_swiss/Ursache_Erdbeben/index_EN/magnitude_energie.png). ## What about erosion? Seems to be planned for later, so I'm stopping here. [Answer] [Plate tectonics](http://en.wikipedia.org/wiki/Plate_tectonics) are the main forces that create and shape land masses. The [lithosphere](http://en.wikipedia.org/wiki/Lithosphere) (earth's crust) is floating on a magma core. As the different plates move grind and bump into each other they cause different effects on the surface. Just like ice on a lake or other large body of water. When two plates collide you get pressure ridges, (mountains) separate and you get trenches ([Mariana Trench](http://en.wikipedia.org/wiki/Mariana_Trench)) often one plate will slide under another. This will raise one up and the other will sink into the mantel. Some plates grind edge to edge like the [San Andreas Fault](http://en.wikipedia.org/wiki/San_Andreas_Fault). All the plate edges are very earthquake prone locations. On a planet with plenty of water it will fill the low spots creating oceans. Many islands are caused by volcanic action along the fault lines under the ocean. Others are the tops of mountain ranges such as the [mid-atlantic ridge](http://en.wikipedia.org/wiki/Mid-Atlantic_Ridge) including the Azores. What powers the drifting? The magma, the planet spin, the moon orbiting, and the sun pulling, all put stresses on the earth to keep things moving, though it is still in dispute how much each one contributes to the whole. Now, how to apply this knowledge to actually making a map. First the important thing to realize is that many of more impressive features are along the plate edges. Knowing the two ways mountains are made (upthrust vs volcanic) would help decide what kind of mountain(s) you put where. A 'Lonely Mountain" really should be volcanic in origin. This works similar for islands in the oceans and seas. Mountain ranges will tend to follow long arcs. Pay attention to elevation, water goes downhill and fills up holes until it finds an outlet. Places like death valley are uncommon, at least without them being filled with water. India ran into Asia and created the Himalaya's, so that is 2 separate plates with large above ocean areas. Barring other factors continents will tend to be lifted up at one end or the other (or both or in the middle etc...) So really large inland seas will tend to be rare, since the continents tend to 'dump' them off. So after having some idea what your continents look like, (expecting lots of arc in their creation), decide where the plates might reside to help explain the features, mountains, lowlands, oceans etc. Apparently I am not nearly so good at describing the uses of the tectonic knowledge for creating maps. [Answer] I've made a bachelor's thesis out of this topic. It contains a throughout explanation on how plate tectonics form the land masses and a simple model that actually does the job. The thesis is available at [Theseus.fi](http://www.theseus.fi/bitstream/handle/10024/40422/Viitanen_Lauri_2012_03_30.pdf) and the source codes along with few screenshots are at sourceforge.net/projects/platec/ . I like the results of my work, e.g. [](https://i.stack.imgur.com/uYTOP.png) has a very nice topography that's impossible to attain with equally simple fractal methods. [Answer] In answer to the second part of your question, there are a number of different algorithms that have been designed for use in procedural game content generation that make use of simplified plate tectonics to generate world maps. An example is [platec](http://sourceforge.net/projects/platec/), but there are many others. These can easily be used to generate realistic looking maps, including in more feature rich simulations, mountain ranges and general heightmaps. However, I am unclear on whether any exist that work with a sphere. - the only examples I've seen are based off of a flat surface. [Answer] When your planet first cools you'll have a choice to make...tectonic plates vs one hard shell. There are examples within our solar system (actually, Earth is pretty unique)...in my personal opinion, I beleive that there needs to be a big impact early in a planets formation to start plate tectonics (The Earths moon being created from the earth is the impact that started earth along it's way)...not sure if I can defend this position with links, but it's a potential conclusion. The main impact on the geology of a planet at this phase is how it's going to release it's energy. -Tectonics. Not much to add here that other answers haven't covered... Moving the plates around on the planet is an incredibly efficient way of releasing the pent up energy in a planet. This motion is going to form mountains along the plates borders (giving rise to mountain ranges). An interesting effect of this is what was once an ocean can be lifted and turned into high mountain ranges. India used to be detached from the continent of Asia and there was a sea between the two bodies. This sea had an abundance of life, including a 20-30 foot long eel like creature that was an offshoot of the Whale (it became a dead end in an evolution sense as they died off, but it shares a common ancestor with whales). As the plate of India crashed into Asia, this sea was pushed high up in the mountain ranges...many many years later, humans find the remains of an eel like mammal deep in the Himalaya mountain range. The Rocky Mountains in north america contain some of the earliest sea life (trilobytes) at some of the higher elevations on this planet. Plate tectonics = ever changing. Early in the galaxies formation (we're talking 4-5 billion years ago), space was a messy place with a crap ton of debris floating around waiting for somewhere to impact (we can see this in the moon where lack of plate tectonics and erosion have left these billion year old impacts place for us to see). The constant change of plate tectonics do much to hide this history and it's only in recent years that we've gained the technological know how to look for ancient impacts on Earth. -Hard shell Planets like Mars and Venus are in this setup where they are pretty much covered by one giant plate and not a series of moving plates...from a world creation standpoint this is actually several times easier to process...one large landmass dotted with Volcanoes to release energy. Volcanoes in this sense become immense stand alone giants that rise out of the ground and tower above anything else. Olympus Mons on Mars is approximately 3 times the height of mount Everest (we actually theorized this mountain existed from looking at mars, long before satellites confirmed it's existence) and over 600 miles wide (about the size of France). It can be seen for a silly distance and will actually stick out past the curvature of the planet. Lacking plate tectonics to change the elevation of the ground leaves meteorite impact much more noticeable on planets that formed like this and it's likely lakes/sea's are left behind impact craters (leaving them a very round shape). Gigantic single mountains and round impact crater lakes...plains nearly anywhere else. Much more straight forward than plate tectonics at any rate as the 'constant change' isn't a worry on a system like this. Incidentally, I've seen the theory that volcanic activity isn't enough of a release of energy for a planet like Venus and it continually builds up the energy and warming the surface 'crust'...in a once every 250 million years in an event that takes over 1 million years to complete, the surface of Venus 'melts', completely reforming itself. I'm really not sure how feasible this is, but it's an interesting theory nonetheless. I guess the rest of the comments here are aimed at your other question threads...Erosion (particularly ice) is probably next, no? You'll need to decide on 'other planetary bodies' to determine gravitational forces on erosion such as tide and the sort. [Answer] Kind of peripheral to the original question, but I have found a "good"(with some quibbles) tectonics simulator here: <http://davidson16807.github.io/tectonics.js/> It should work with most modern browsers, and is usually good at producing credible maps. Because of the way the spherical surface is partitioned into cells the edges are a bit sketchy, and it's intrinsically slow, especially if your browser doesn't have a good js implementation, but it's pretty cool. [Answer] The best way to start designing a realistic world I found [here](http://www.giantitp.com/articles/xO3dVM8EDKJPlKxmVoG.html). In my answer, I will use some of the thoughts from that article. I think of the world as a pitted soccer ball, where elevation rises and falls. The low parts are swallowed by the ocean, average height is your flat lands, and your high points are mountains or islands if they are isolated from other high points. Now each section of the soccer ball is a separate tectonic plate. You can change the number of plates, how each one is shaped, but in the end your plates will join together to form a sphere. Where each plate meets, the elevation gets higher as they push together and rise. Mountains form where the plates crash together. Where the plates enter the ocean, you will typically find a few islands nearby as the land is pushed just high enough to rise over the ocean. When designing your map you can start with a concept, the overall shape and feel of the continent and a few important mountain ranges. Then you can draw the plates on top of that sketch along the mountain ranges to flesh the map out and guide the placement of more mountains and islands. Or you can start with the plates, just whip up a few shapes that run into one another, draw mountains at the intersection then gradually give way to ocean as you retreat further from the mountains. It is really up to you. You can also figure out how your landmass came to be. Did your world just slowly rise out of the see? Your seacoast is likely smooth and gradually falls off into the water. Do you want a [Pangaea](http://en.wikipedia.org/wiki/Pangaea) that split, caused upheaval and potential for conflict like the merging of India and Asia? That could give you more ocean cliffs from where the land split. The final factor is water. Where are your rivers, lakes, and floods? Has there been time in your world to cut the Grand Canyon out? You can draw rivers from the mountains you create in the previous step to the ocean. The path it takes is the lowest elevation at each point, and the constant flow of water just makes it lower over time. ]

[Question] [ During much of the Cretaceous period, oxygen levels were substantially higher than they are currently, with estimates indicating that [around 30%](https://www.npl.washington.edu/AV/altvw27.html) of the atmosphere consisted of oxygen. Obviously, this indicates that species that evolved during this time period would be likely to require these levels of oxygen to support their metabolisms. This raises the question of how these species would fare if suddenly transported into the modern world. Obviously, there would be some difficulty, but how severe would it be? Humans are capable of acclimating to lower oxygen levels while climbing mountains, would dinosaurs have to have some kind of similar acclimatization process (possibly in an artificially oxygen-enriched transition environment where the oxygen content is decreased more gradually)? **Essentially, how much trouble would Cretaceous-period dinosaurs such as Triceratops or Tyrannosaurus Rex have in adapting to a modern atmosphere?** [Answer] There's evidence dinosaurs in general had the same sort of respiratory system that the modern dinosaurs have kept, which is *more* efficient than the system used by mammals. This is suspected to be part of the reason why they could get to such a huge size; they could more efficiently process it to extract the oxygen, and there's no reason to assume they'd have it any more difficult than today. Here's a chart of [oxygen levels since the Silurian](https://www.earthmagazine.org/article/flammable-planet-fire-finds-its-place-earth-history): [](https://i.stack.imgur.com/6u1Yg.png) You'll note that the period of low oxygen in the Triassic was significantly lower than today...and that's when dinosaurs solidified their dominance, due in part to their better oxygen extraction system. There were subsequent times when oxygen levels dipped to near-current levels, and again, dinosaurs kept on ticking through. Based on that, there shouldn't be any reason why dinosaurs from the Cretaceous should have any significant difficulties based on the amount of oxygen in the air. There were land mammals even larger than the dinosaurs you name who thrived at current oxygen levels, so clearly larger animals than are present now are possible. For example, T-Rex is estimated to have massed between 4.5 to 14 tonnes (depending on assumptions about how heavily built they were), and *Triceratops* 6 to 12 tonnes. The Asian straight-tusked elephant *Palaeoloxodon* is estimated to have been up to 22 tonnes; *Paraceratherium* 15 to 20 tonnes; the steppe mammoth 14 tonnes; *Deinotherium* 10+ tonnes; and so on. [Answer] To a lazy first approximation, the O2 concentration now is about 70% of what it was back then. To get a similar effective difference in the partial pressure of oxygen, you can go to an altitude of about 2900m. Without acclimatization, this can be quite unpleasant (or potentially [life threatening](https://en.wikipedia.org/wiki/Altitude_sickness#Severe_symptoms)) and physical activity can be challenging. It *is* possible to acclimatize to such environments though, and regular humans can [live their entire lives at higher altitudes than this](https://en.wikipedia.org/wiki/List_of_highest_cities). Modern archosaurs (in the form of avians and crocodilians) have got fancier lungs than mammals do, and may fare better. The more energetic the lifestyle of the dinosaur, the more they'll suffer from the oxygen deficit. A herbivore might cope OK, but a predator might not be able to run fast enough and pterosaurs might not be able to get airborne at all. There may, of course, be other unknown issues with dinosaur metabolism that make them less able to weather the change; we're not likely to discover those without actually conjuring up some suitable dinosaurs to experiment on. [Answer] The Cretaceous period was long. There were periods when oxygen was 30% and there were periods (after massive volcanic eruptions) when there were 18%. I can't say it had no effect on the biosphere, but dinosaurs (and T-rex especially) kept their apex positions in both cases. But these changes were slow, taking place over the course of generations. So these dinosaurs had time and conditions to adapt. But if we just put these dinos out of their age (where oxygen concentration was high) to our time then there might be some problems, but not much. T-Rex was a long-walker, but a short-runner, about hundreds of meters - like a cheetah. It was running on inner reserves (like cheetah do now) and the amount of reserves does not depend on outer conditions. It would just take more time for replenishing these reserves. So it would be able to do this run not say (I don't know exact numbers) once an hour, but once one and a half hour. On large scale it will reduce "net meat income" for T-Rex *population*, but for single animal it would not make a big difference. Same thing is for other types of dinosaurs - they will get tired faster, but that would not matter much on individual scale (unless you are doing some beast-pit battles), since their predators (or preys) would also tire faster. ]

[Question] [ **This Query is part of the Worldbuilding [Resources Article](https://worldbuilding.stackexchange.com/questions/143606/a-list-of-worldbuilding-resources).** --- Whenever I draw coastlines for a map, I find myself simply drawing large curves and adding in small squiggles in between, occasionally varying things a little for river deltas or small peninsulas. This gets boring after a little while, especially when I do it on a large scale. * What are the processes that cause various shapes in coastlines to form? * How can I harness these processes to accurately construct bays, peninsulas, river deltas, etc.? If anyone knows if [Slartibartfast](http://hitchhikers.wikia.com/wiki/Slartibartfast) is around to talk about fjords, then I'd love to have him answer. --- Note: > > This is part of a series of questions that tries to break down the process of creating a world from initial creation of the landmass through to erosion, weather patterns, biomes and every other related topics. Please restrict answers to this specific topic rather than branching on into other areas as other subjects will be covered by other questions. > > > These questions all assume an earth-like spherical world in orbit in the habitable band. > > > --- See the other questions in this series here : <http://meta.worldbuilding.stackexchange.com/questions/2594/creating-a-realistic-world-series> [Answer] ## It's pretty much random. But that's a good thing, because it allows for creativity. The main driving factor here is erosion. The coastal details are random, but some major features depend on the type of land at the coast. * First we can discuss a collection of [major features for a coast](https://en.wikipedia.org/wiki/Coast) and a bit about how they are formed. * Then a couple notes on how to get the big features right. * Finally some sources for generating your coastlines automagically. ## The features: [](https://i.stack.imgur.com/uVkr8.jpg)[$\_{Source}$](http://visual.merriam-webster.com/earth/geology/common-coastal-features/common-coastal-features.php) Roughly from left to right: * [Beaches are formed](https://en.wikipedia.org/wiki/Beach#Beach_formation) primarily of the sediment deposited along a coast from the erosion of a surrounding cliff, or bluff. * A rocky cliff is made up of material which is relatively resistant to erosion such as sandstone, limestone or granite, a flat rocky [wave-cut platform](https://en.wikipedia.org/wiki/Wave-cut_platform) or abrasion platform is formed in front of the cliff. * The [headland](https://en.wikipedia.org/wiki/Headland) is the land on top of the cliff. * (Not listed) A bay is a beach surrounded by headlands. * Sea caves are made when certain rock beds are more susceptible to erosion than the surrounding rock beds because of different areas of weakness. These areas are eroded at a faster pace creating a hole or crevasse that, through time, by means of wave action and erosion, becomes a cave. * Natural arches are formed when a sea cave is eroded through by waves. * Stacks are formed when a headland is eroded away by wave and wind action or a natural arch collapses. * Stumps are shortened sea stacks that have been eroded away or fallen because of instability. * A [skerry](https://en.wikipedia.org/wiki/Skerry) is an eroded stack. * [Spits](https://en.wikipedia.org/wiki/Spit_(landform)) are formed by ocean currents colliding and depositing materials. * A [tombolo](https://en.wikipedia.org/wiki/Tombolo) is formed when a spit connects to an existing island or builds up enough to create an island. * A rocky [islet](https://en.wikipedia.org/wiki/Islet) is a small island. Perhaps a disconnected tombolo or a isolated skerry. * A river [estuary](https://en.wikipedia.org/wiki/Estuary) is a bay or inlet with a river flowing into it. * Sand islands are disconnected spits or the result of river deposits. * Dune is a planet with giant worms and spice. Also a pile of sand. * A [lagoon](https://en.wikipedia.org/wiki/Lagoon) is separated body of water, usually salty, and occurs quite frequently. Most of these features can occur anywhere, but have a better chance of sticking around depending on what the land is composed of. ## Getting some clues: There are some features/properties that will aid in the selection of features. These aren't rules, but guidelines. For instance: **Reefs and offshore features** An offshore reef or island will significantly reduce the wave strength and you'll get some fairly lackluster beaches. They'll mostly be sediment build up and will likely result in shallow beaches (look at [beaches on the Australian mainland](http://static.laterooms.com/hotelphotos/laterooms/157724/gallery/rydges-esplanade-resort-cairns_141120110205205771.jpg) inside of the great barrier reef for good examples). **Winds and hemispheres** If there are high waves there will be more erosion and the coastline will more likely have been pushed landward until it hit some rocky materials to slow the encroachment. The high waves are caused by high winds. So, these rocky coasts are characteristic of the [west coasts](http://www.travelportland.com/wp-content/uploads/2013/08/NR_OregonCoast_Overview_12855646_ZachSchepf_.jpg) in the northern hemisphere and the east coasts in the southern hemisphere. **Latitudes** If the coastline is filling an area forged by a recent ice age or glacial activity, then large cliffs may be more prolific. The glaciers will have carved out deep valleys, leaving bedrock as the headland which resists rapid erosion. See the [fjords](https://en.wikipedia.org/wiki/Fjord) in near-arctic regions for examples. ## Automagical generation: Coastlines can be passibly simulated using [fractal landscape](https://en.wikipedia.org/wiki/Fractal_landscape) generation. I found [this article](http://scienceblogs.com/goodmath/2007/07/17/fractal-curves-and-coastlines-1/), which describes how the author algorithmically produces a coastline fractal by adding a random component: [](https://i.stack.imgur.com/kKtdd.jpg) Also [this one](http://www.cartographersguild.com/showthread.php?t=23509) doing a similar process: [](https://i.stack.imgur.com/j9X6C.png) [Answer] **Speaking from experience:** I began a similar sounding project a few years ago, with layers - arrays of varying sizes, each square, each functioning as its own 2d fluid simulator, labeled 'innercore', 'outercore','mantle', 'crust', 'hydrosphere', and then 'atmosphere'. They mapped values, provided particular methods to describe behavior through the simulation, and impacted on other layers in various ways. I would convert my data into .bmp images for easy testing and then project the data-points as variations of magnitude on simple spherical-shaped objects on an OpenGL application. On the crust layer, the most detailed, I'd have multiple datapoints per 'pixel', for elevation, change in elevation, granularity(for determining erosion rates and textures), and some other values for path-finding and logic (basically bit-crunched surface normals). Using this method, I was able to generate simple and convincing landmasses by pausing at various times during the simulation. I wasn't satisfied with static maps because I was modeling populations and genetics and I thought it was silly the map would be static and unmoving so I ditched the Civ-style fractal generators and, imho, was able to generate more convincing terrain features with the simulator. My atmosphere layer reacted to elevation of the crust and 'evaporation' off exposed sections of the hydrosphere, thus producing rainfall patterns and watershed formations. My hydrosphere gave me oceans, tides, and a water-table which in turn defined the rivers and lakes. Because they all used roughly the same methods, akin to fluid dynamics, I didn't have to pull my hair out being explicit about defining and sub-classing things such as Mountain\_Chain, River\_Delta and quereying Pathfinding.riverpath and other such nonsense. It all occurred, for lack of a better term, naturally, arising from the simulation. Erosion was achieved through a 'granularity index' (think solid-rock, boulders, slew, sand, etc) and this caused canyons and river valleys to form, and even gave me things like sandbars and dunes. I was working on a method for interpolating values (cause I wanted to zoom) when I got distracted by a rare encounter with a female. Eventually, when I returned, my OCD began to kick in and I never completed the methods for the interpolation of 'fine' details because I became increasingly and inconsolably perturbed by subtle frustrations resulting inevitably from attempts at mapping a SQUARE set of data over a CURVED surface. I tried everything, and everything failed me. I once, caught up by the vanity of youth, even became a vocal enthusiast for something called a quincunx. What a fool i've been! Eventually I found [this](http://onlinelibrary.wiley.com/wol1/doi/10.1029/2007GC001581/full) and decided I should re-write the simulator using discrete points along an Archimedean spiral. I sorta burnt out on that project, though. it showed much promise! I recommend - highly - to do away with those tired old fractal-based generators - this isn't the 90's anymore! EVERYTHING is a fluid at various states of arrest - so to me it makes sense to use a fluid simulator. You should map the data using the methods [they](http://onlinelibrary.wiley.com/wol1/doi/10.1029/2007GC001581/full) describe cause it's OCD approved. And singularity-proof. Although, you'll have to learn how to invert incomplete elliptic integrals of the second kind, I'm sure you'll figure it out. Ain't no hill for a stepper! [Answer] If this is the proposed method: > > 1. Do a rough global land mass. > 2. Divide it into plates. > 3. Move them around - creating mountains where the converge on land and chasms where they diverge and sharp breaks where they slide past > each other. > 4. Decide that these bits will erode from glaciers and these bits will erode from coastal flows (and these bits by rivers?) > 5. Decide on a global climate, ocean currents and rainfall and rivers (not decided previously) and therefore vegetation etc. > > > then I think that is both a hard way to do it and likely to produce poor results without an enormous amount of effort. Steps 3, 4 and 5 should all be happening at the same time. Tectonic movements can and do make significant changes on the timescale of erosion and deposition. The changing shape of the land will affect coastal flows, rivers and weather systems. I don't think you will be able to adequately simulate the intricate processes of geology like that. I suggest a slightly different approach: 1. Do a much less rough map. Ideally generate it using the techniques of fractal landscapes (there are very sophisticated tools available for this), which will produce much more realistic randomness than a human could: [](https://i.stack.imgur.com/y4Bof.jpg) 2. (Optional) Copy (imprecisely - the less precisely the better) some real features from real maps (from Earth or elsewhere). They can be distorted and in sections. Put them wherever you like; wherever looks right. 3. Decide on plate boundaries that will have lead to that situation. E.g. mountain range here implies a convergent boundary; chasm here might be a good place for a divergent boundary; sharp edge here, maybe a transport boundary. 4. Tweak the map in accordance with those boundaries: make mountain ranges on convergent boundaries more ranging. Between two convergent boundaries there will be a divergent boundary. Put volcanoes and chasms there if they weren't already. Volcanic islands if it's out to sea. And so on. Remember plates can hinge/rotate. A convergent boundary of a rotating plate will produce a mountain range of increasing size. It's far side will be a curved transport boundary. 5. (Optional) Gently tilt, elevate, and depress some areas of land (whole continents) along plate lines - submerging into the ocean or raising the sea bed on to dry land. 6. (Optional) Add the results of ice ages (gouged out valleys near the poles) and rocky deposits at their extremities. 7. Decide on sensible global winds and ocean currents and temperatures. 8. Smooth out rough bits that protrude into those currents and add smooth deposition places further down stream of those currents - where the current's course changes, slows or becomes shallower. 9. Decide on rainfall based on the air currents, elevations and temperatures and make sure rivers lead from them downhill to the sea with lakes along the way if they pass through depressions. 10. Do some erosion and deposition (flood plains, deltas, etc.) for the rivers. 11. Decide on vegetation based on climate, rainfall and proximity to rivers, lakes and coasts. The more care you put in the better the results will be but I think good results will come from a lot less effort then the 'from scratch' approach. [Answer] A quick way I have found useful is to look at an actual map and take country, states, lakes, and other real life formation and invert them, flip them, rotate them etc... Ex: Trace the Black Sea outline then rotate it 90 degrees. You now have a kidney shaped continent. The "water" would be your actual land mass and the surrounding land would become your oceans. Many famous authors do this. Westeros (Game of Thrones) looks very much like England. Its just larger(about the size of South America) Warhammer (Games Workshop) is extremely close replica of our actual world with slight changes. Another series ( i forget the name of it) basically used Alaska and inverted it. Also the leaf method. Take a leaf(preferably a large one). Crumble it a bit on the edges to get the jagged appearance. This is easier in the Autumn. Then trace that edge pattern rotating around the map. There is a cool Youtube channel (Questing Beast) that does a lot with map drawing. Here is an idea for dropping sugar cubes and tracing the pattern. (Unique way. he has great mountain and forest stuff as well.) <https://www.youtube.com/watch?v=m10GJCCbj0A> After you get the coastal boundaries then you can begin to add everything else. [Answer] I can offer a quick and dirty method that relies on the fact that coastlines and other geographical features are fractal in nature and, therefore, show self-similarity in all scales. That is, a coastline looks the same at the scale of one meter as it does at one kilometer. Unless the human eye has something other than the fractal shapes to provide scale e.g. a vehicle, city, roadway etc., geographical features on images look realistic even after you scale the image up or down. The higher the resolution of the image you start with, the more you can scale up while keeping the realistic fractal properties. So nip over to google maps/earth or some other similar service(s) and start looking for islands. I suggest Indonesia, the Philippines, the Aegean, the coast of Alaska and B.C. etc. Gobs of islands in all shapes and sizes, most of which no one who isn't from there would recognize. Pick some small obscure island, grab as high resolution image of the whole island as you can, then load it into your favorite image editing app. To obscure any possible familiar outline, rotate the image to some arbitrary angle other than the one it holds in reality and/or mirror it right-to-left or up and down. Somewhat surprisingly, I've found that we are so used to seeing land masses in specific orientation that even a minor change in orientation makes them unrecognizable to most. Then scale the image upward until it reaches the scale, on your map, of the landmass you want and presto, instant novel land mass continent with realistic coastlines, and usually all other terrain features as well. The same basic trick works on all geographical features because they all have fractal properties just like coast lines. Creeks scale to the Amazon, and often hills make passable mountains (although not always, some hills are degraded mountains but others result from other actions like glaciers. In many cases you might find them too rounded.) If they don't you can always swipe mountains of craggy hills from some other part of the globe, rotate, mirror, scale, and drop it on the continent. You can also, with some practice, create a union of two resized islands together to make a completely novel profile, although making it look seamless is trickier than than it sounds. In this case, the fractals are working against you. It's easy to get plains and other flatlands to merge fairly transparently but usually not mountains or other rough terrain because the transition in scale becomes apparent along the seam. Also, don't forget coastal plates under the water. The edges of the plates look very much like coastlines for they undergo a very similar process of erosion. They even have rivers and channels. In thinking about it, I've only done this in 2D but with the 3D mappings out there, you might be able to pull the same trick in 3D to make a fly over. It's been a while since I used this method to cobble together a quick world for a friend so I apologize for not having an example at hand but I think the idea is simple enough for everyone to grasp it. At the very least, it's a good way to quickly prototype a world in preparation for using a more sophisticated method. Gotta love fractals. [Answer] Could this be like something you're after? [](https://i.stack.imgur.com/uYTOP.png) For just coastlines, I think fractal methods are better, but if you want the entire topography, I recommend plate tectonics, e.g. as in the [PlaTec](http://sourceforge.net/projects/platec/) project. [Answer] **First, consider the steepness of the land off the coast.** How quickly does the land drop off into the ocean? The faster it drops off, the more likely you are to have steep cliffs along the coast, maybe a few sea stacks, and then open ocean. Long archipelagos trailing off from the coast will be found in regions where tectonic boundaries run perpendicularly away from the coast line.In places where the sea slopes off over a longer distance to the edge of the continental shelf, the coast will have more large-scale structures. Alaska, for example, has a mountainous coast with lots of islands, but is close to the edge of the Pacific plate, and hence runs in a fairly straight line on a larger scale, with no major protrusions like the Canadian Arctic Archipelago or Florida. In addition, structures like barrier islands are generally more common where the land slopes gently into the sea. **Next, look at the general land forms just inland from the ocean.** On a slightly smaller scale, one of the biggest drivers of coast line structure is the type of land that it forms next to. The coast of Southern Alaska, for example, lies next to a large range of mountains. This geological unevenness creates a fairly broken looking coastline with lots of large islands along the coast. On the other extreme, the coastlines of southern India slope gently into the sea, forming few islands and lots of long, smooth sandy beaches. The coastal features found in a particular region will also depend heavily on the climate type. Flatter regions will form flat, sandy spits and barrier islands, while steeper coasts will form rocky outcroppings and mountainous offshore islands. **Look at erosive and constructive processes that will modify your coast.** Volcanoes, glaciers, and rivers can all change a coast line. Lava pouring into the ocean can extend and smooth out coastal features, filling in small valleys and pouring into bays, while at the same time creating longer outcroppings of rock in the places where lava enters the ocean. Glaciers can form long, steep valleys cutting into the coastline, known as fjords, and rivers can form either long inlets cutting into a coastline or build deltas extending out into the ocean, with the former occurring more often in deep waters and the later forming on top of shallow continental shelves. Following these steps should give you a coast line that looks more 'real', and will make maps more varied than applying random noise equally to every region of your map. You can, of course, go into more detail about how a coast forms, with areas with lots of sand accumulation forming dunes, and different erosion patterns dominating a section of the coast based on the orientation of underlying rock strata. [Answer] I checked briefly the other questions and my answer won't be anywhere near the same caliber (I think) - but to get things going: **Drainage basins and elevation** I normally always start with drainage basins and their rivers and lakes, and base both my topography (well those two are a bit more simultaneous than one before the other in my case) and coastlines off it. That's what determines my bays and deltas and fjords etc... Afterwords it goes with the coastal elevation, higher elevations close to the sea will have a more jagged coastline, steeper slopes have tiny streams rivers dumping into the sea so those also act in forming it, where lower terrain will be 'smoother'? Obviously the scale of the map is going to change a huge amount of things. ]

[Question] [ The situation I'm considering is as follows: A large research vessel with a crew of about 100-200 attempts to land on a potentially habitable planet, but *something* goes wrong during the descent. A few crew members who happened to be close to the escape pods managed to escape the ship and land nearby (about 100-200 meters). I would like the survivors to be able to investigate the crashed vessel, but they should find everyone *dead* or *missing*. The vessel should only have minor damages, implying little atmospheric burn-up; presumably because the descent complications happened closer to the planet's surface. I also want the ship to eventually explode, perhaps due to a nuclear reactor meltdown. This could happen days later, giving the survivors some time to explore the ship. I'm wondering what could have happened to the ship during the descent that would: * Leave the vessel relatively intact. * Kill or "remove" the crew. * Leave the survivors unharmed in their escape pods. * Be undetectable from orbit because the crew of a scientific research vessel should know better. * Potentially be the cause of the ship exploding, though it could be assumed that the reactor meltdown is caused by the physical impact of the ship against the planet. Ideas I was considering include: * An electrical disturbance, such as an undetectable storm or an abnormality in the planet's ionosphere (?) that killed the crew by electrocution, but the escape pods weren't struck. Though, this seems too "convenient". * A gravitational disturbance that violently shook the massive ship, killing the crew, but had little effect on the small escape pods. * If there could be no effective "natural" explanation, I could resort to alien interference, such as an advanced weapon. Though I'm unsure if I want there to be intelligent life inhabiting the planet. [Answer] A failure of the inertial dampeners. The overengineered ship hits the ground at 100 m/s and skids, scuffing up the hull and tossing things about in the interior... including the crew. All are dead from trauma by the time the ship, still functional, comes to a rest. [Answer] High altitude depressurization. It has happened in real life: [Soyuz 11](https://en.wikipedia.org/wiki/Soyuz_11) Soyuz 11 was USSR space mission launched on June 6, 1971. After successful completion of work aboard space station Salyut, on June 30, 1971 the spaceship started the return trip. Everything was normal until audio contact with the crew was lost before reentry began. The descending capsule had landed visibly intact, and only after opening the hatch the ground crew discovered that the three cosmonauts aboard were dead. > > Kerim Kerimov, chair of the State Commission, recalled: "Outwardly, there was no damage whatsoever. They knocked on the side, but there was no response from within. On opening the hatch, they found all three men in their couches, motionless, with dark-blue patches on their faces and trails of blood from their noses and ears. They removed them from the descent module. Dobrovolsky was still warm. The doctors gave artificial respiration. Based on their reports, the cause of death was suffocation." > > > The three crew members of Soyuz 11 are the only humans known to have died in space. [Answer] A leak of some kind from the piping that runs throughout the ship1, which exposes the crew to toxic gasses. A handful of the crew who are near the escape pods survive, but the rest die horribly. The ship is in automated descent mode and lands safely. The leak could be in the reactor coolant. Without that coolant, the reactor will eventually "explode". 1 All ships have miles of piping and conduit running through them. Some of those pipes will carry necessary but hazardous chemicals. [Answer] A simple hull breach will do. The ship might land softer than a bird, but there is very little oxygen in space and in the upper atmosphere. If you don't like the idea of a breach, it might just be that the O2 generator of the ship stopped working. This may allow for select individuals or animals in extasis to still be alive, and will be less damaging to the ship than most other options. The ship may land intact, piloted by AI. [Answer] **Time dilation field.** I really like the "removed" possibility. The investigators find the crew is gone. In the version I am thinking of, the crew is gone. The interior of the ship is OK but has changed in several ways from how it was a few hours before when the escapees left in their pods. There are extensive repairs of things that had not been broken before. Entire rooms are purposefully rearranged. Many things are falling apart, worn out. The survivors find a classroom for grade school children. There had not been any children aboard the ship. Around the planet is some ancient alien tech - a field used to help launch ships to escape velocity or some such. The field interacts with the research ships tech to produce a time dilation field. From the perspective of the persons in the ship, the outside world froze. Inside the ship, six hundred years has passed. The crew is still aboard the ship, as are their children and their grandchildren. They are dust. [Answer] If you want a reactor meltdown, you could have a random failure of the reactors, leading to high levels of radioactive material throughout the ship that killed everyone through radiation poisoning and or/outright toxicity (such as plutonium poisoning). The ventilation spread it through the ship without the reactor failing catastrophically immediately. Perhaps combine that with some weird coolant that melts human tissue if you really need some disappearances. Eventually a coolant leak caused the reactor to overload, explode, whatever you need. Perhaps the descent required additional power, such as to maintain heat shields, and the increase in energy usage led to a previously-undetected problem with the reactor (or a problem they thought at the time was only a small one) to cause a failure. Or you could combine it with something else, such the failure being cause by a gravitational anomoly or just some unexpect air pockets that shook the ship a little too much. Again, the crew might have known about such potential issues, but thought the reactor could handle it. And there is always the possibility of outright sabotage of the reactor, or someone not doing their job properly, or cutting corners to save cost, etc. [Answer] ## Sudden Deceleration is easily lethal Never mind the escape pods (unless they're integral to your story elsewhere), due to miscalculation the ship hits atmosphere much sooner than expected, and slightly off-kilter. The sudden deceleration, and desperate corrections by the pilot fling everyone within the ship around like ragdolls. The few folks who are in crash couches (like the pilot) suffer minor bruising. Anyone who isn't strapped down is thrown violently across whatever room they're in. Additionally any unsecured items could also be potentially lethal. If escape pods are integral, remember they probably have crash couches as well, and a few people are likely to have been near them and just barely had time to enter and activate them. If you want the pilot dead, maybe she has time to enable autopilot/emergency systems but not enough time to strap in (or even faulty straps). ## Injuries suffered during crash and evacuation A less than perfect landing could easily cause a pretty big fire in the crash zone, dangerous to escape through, and dangerous to evacuate wounded through (assuming some people got lucky and survived getting tossed around during reentry/crash). Alternatively if the ship lands in a precarious position (cliff/hillside) it could slide minutes or hours later, injuring or killing everyone who thought it was safe to get out of the crash couches and tend to the wounded/evacuate. [Answer] G-Force (Spinning) It has [happened before](https://gizmodo.com/the-first-man-to-walk-in-space-almost-got-stuck-out-the-1441927234). If the craft goes into a spin, it can easily kill the crew without doing any damage to the craft. [Answer] Atmosphere getting in, if the hull breaches at lower altitude it may not be decompression that is the issue. Depending when in the descent a small breach forms: * plasma from aerobraking could cook the crew while leaving the independently heat shielded escape pods intact. * toxic trace gases in the atmosphere that may or may not have been detectable on a long range spectral scan could leak in and kill the crew but the escape pods have their own air supply and remain intact. Upon landing the ship may start a fire in the local environment, if the gases given off by the native vegetation are toxic the first you find out about it could be when you open the hatches after you land, you have no reason to scan an atmosphere you already "know" is safe. Equally if the hull has a small breach, ordinary immaterial to normal operations, toxins from burning otherwise harmless plants may leak in and kill those without a closed air supply. [Answer] It rather sounds like you would prefer the ship to be found empty. I have a solution for that: Intoxicants. The scenario goes something like the following. An explosion occurs on board the ship when some piece of equipment fails near the escape pods. In addition to cutting off communications between that compartment and the rest of the ship, it also contaminates the life support system with an intoxicating chemical. The isolated crew members panic in the belief that the ship is coming apart and hop into the escape pods. The air quality monitoring systems do not pick up this particular intoxicant in time, as it is something outside the scope of their design. (Possibly even formed during the abnormal conditions leading to the explosion. Details will depend on your technology.) The crew get drunk as lords before they can realize what happened and go ahead with the landing. The computers handle the landing which goes ahead mostly as planned, although hampered by the damage to the ship and the improper behavior of the crew. After landing, the intoxicated crew decide it sounds like a great idea to go on an excursion while taking useless junk and leaving their survival gear behind. They get eaten by a grue or any environmental hazard. While all of this goes on the cabin air continues to circulate through the filtration system and is eventually cleared of intoxicants before the survivors show up. Systems damaged or improperly repaired by the drunken crew—or equipment not properly strapped down for landing—can cause enough damage to lead to whatever type of explosion you wish to destroy the ship with. One last thing: This scenario assumes that the crew must be breathing the cabin air. Normally we expect the crew to be wearing IVA suits for landing ([Soyuz 11 had a lot to do with that](https://en.wikipedia.org/wiki/Soyuz_11#Death_of_crew)). It is preferable if the accident happens on approach rather than during atmospheric entry, so no-one had put on their suits yet. In case anyone were wondering, I based the scenario on (probably false) claims of how [Franklin's expedition](https://en.wikipedia.org/wiki/Franklin%27s_lost_expedition) could have been lost as a result of insanity caused by lead poisoning. [Answer] Overheating. The ship could be approaching at the wrong angle, suggesting that the ship will burn up on re-entry. This is why the escape pods were launched. The ship did overheat, reaching an internal temperature of 150-200c for a sustained period of time. Enough to kill the occupants but not destroy the ship entirely. The escape pods either have better heat-shielding (it's easier to shield a smaller vessel) and/or had their own propulsion systems that allowed them to adjust their entry angle. [Answer] Some options come to mind: * An experimental virus that cracked open when the ship crashed. * A toxic leak from some sort of equipment. * The escape or cryo pods could be cushioned. Anyone not in one could die on impact or due to a gravitational disturbance during re-entry. [Answer] Subnautica has this plot, even some of the finer details are there. The Aurora is a **1.2km long** ship with a large crew which attempts to perform a slingshot maneouvre around an ocean planet on its way to another destination. **It is attacked from the planet's surface**, and the captain attempts a controlled descent. He guides it into shallow water inside a volcanic crater. **Thanks to his efforts the ship lands mostly intact**, but he dies in the process. A sizeable portion of the crew gets into **escape pods** and these mostly land within the volcanic crater, **within about 2 km** of the ship. A lot of these evacuees **survive initially** and some are able to rendezvous. Hours later a **radioactive explosion** happens on board. Though this explosion does little further damage to the ship, it unleashes a wave of radioactivity on its surroundings. With the appropriate radioactive protection, the player can **investigate the ship** (even after the explosion), but they find **no living occupants**, other than the few ocean creatures which have swum or crawled inside. I have not played the game fully but there are teleporting creatures which I think are able to **remove people** from inside an escape pod. So to fit this in to your question, * The ship lands mostly intact because the captain was able to bring the descent under control. * The crew left behind in the ship were killed on impact, and the survivors who escaped in pods were eventually hoovered up by teleporting aliens. * Some of the people in escape pods were able to last a few hours when left to their own devices, because they were often trained, they landed in water and the pods had survival gear installed. * The turret which attacked the planet was small enough not to be easily seen from orbit. * The radioactive explosion was caused by the impact. I know you weren't looking for an explanation caused by intelligent life. I just thought you described the plot of this game so perfectly, that I had to bring it up. [Answer] **Use a non-earth material for the vessel** You did not specify, what material the vessel is made of. In that case I'd suggest you to say, that they got the material for the vessel from a different planet and it's nearly indestructible. This would help you in different ways: * Leave the vessel relatively intact: + Even though it fell "from the sky" it still wouldn't break * Kill or "remove" the crew + The ship is still intact, but because of the impact, the crew died * Leave the survivors unharmed in their escape pods. + It's a research crew. They don't carry weapons while they're on the vessel. You could say, that there wasn't enough time to get weapons because they were stored at the bottom of the vessel / in a save (this part of the vessel could also burn or be unreachable because of a different reason) [Answer] There is the always fun option of Artificial intelligence tasked with maintaining the ship, and the safety of those aboard the ship, designed to always keep the ship going even at the expense of some crew (well all the crew are dead if the ship stops being a ship) As they are approaching the planet a gravity fluctuation causes a issue with the reactor, getting to work the AI realises the best option for saving the ship is to harvest *McGuffinium* a rare isotope that has ended up in the crews bodies as a trace element from contanimination of living on the ship (and is also the reactor) This process involves centrifuging out the *McGuffinium* liquefying the crew, as as the maintenance bots get to work shredding some of the crew, the AI also forcibly ejects those with a good survival chance out of the ship in the escape pods as much as they resisted and tried to stop their crew being killed. [Answer] How about a software failure? The crew noticed some unusual activity in the nearby sun. They foolishly decide to investigate and get caught in a solar flare that acts like an EMP, damaging the circuitry of the shipboard computer which maintains all systems. It recovers... but not completely. Some of the processors are malfunctioning and every time they are accessed a few more errors are introduced into the system. Things start going wrong. The course calculations look off. The entertainment system hiccoughs. Communications shut down and restart. The crew decides to land on the planet to effect repairs. They get weird readings from their sensors. They send a guy down in a pod to do a visual inspection of the landing site. Unbeknownst to them, life support has not been functioning correctly and carbon dioxide has been building up inside the ship. While he is gone, everyone suffocates. He is able to land the pod manually. The ship lands itself more or less correctly with little or no external damage but the software gets progressively worse. Eventually, the reactor safety system fails and there is an explosion. You have the option of introducing a few more disasters or mysteries along the way like strange, garbled messages being broadcast or thrusters suddenly firing for no reason. Hope this helps. [Answer] The planet was mapped and entered into the Galactic Claims Database by a US vessel a hundred years ago. When the brand new research vessel enters into a de-orbiting trajectory, parts of the crew are in escape pods (harboring the secondary bridge and data backups as well) as a matter of protocol. As soon as the vessel passes the point of no return, systems adjust themselves to planetary protocol. Which because of the nationality of the claim-stakers a century ago encompasses a switch to US units. Some software was written by people unaware of alternatives to metric... Life support scrambles to achieve atmosphere at psi numerical values of pascal. The capsules eject. Everyone still aboard shakes their fists, groans, and dies. Fuel pellets that need only be added every few days get readjusted from mm to inch-values, spelling doom for the vessel as soon as they get inserted into the tokamak. [Answer] A previously unknown and undetectable molecule within the alien planet atmosphere. As the ship descended, at an atomic level this mysterious molecule had a violent and combustible/electrical reaction and integration into the molecules that make up the metal parts of the ship. Anything organic in nature that had contact with metal during its molecular change was vaporized. This process was super fast and intense. Afterwards just as quickly the metal stabilized, but now it has this added molecule. (investigations afterwards will detect and isolate the change in the metal, recognizing belatedly that this molecular reaction will be planet-wide to all alloys of metals not native to this planet) This difference can explain why your reactor will eventually degrade its once effective metallic protections and safeguards and go into meltdown mode. Also, you can explain how the crew in their escape pods survived. Firstly, (purely by luck or happenstance) they are not metal but maybe a super advanced life saving type of non-organic nanotech. Also, you could incorporate how different alloys of the ship delayed or sped up the violent molecular reaction. Thereby giving crew in different parts of the ship the ability to escape while other others had no chance. (metal seats/restraints for pilots, ceramic tile walkways, etc.) As an additional measure you could employ various levels of injuries to the survivors because they were wearing metal belt buckles, glasses, hair clips, etc. [Answer] As the ship is heading in to land, it is heading over a spot where a strong nuclear chain-reaction is going on, down at the bottom of a volcano (or other hole that limits the beam of emitted particles to directly above). A few crew members see the Cherenkov glow coming up ahead and jump into the pods and leave, but the body of the ship passes through the enormous flux of neutrons (or maybe gammas -- have to worry about atmospheric transmission, though), which kills everybody remaining on board. [Answer] When a plane is landing, crew usually strap themselves with (seat)belts as a security measure. Your ship didn't use physical belts, but [magnetic anchor points](https://www.google.com/search?q=magnetic%20anchor%20points) (kind of like [magnetic door holders](https://www.google.com/search?q=magnetic%20door%20holders) but stronger), powered by the ship's electrical systems. During the emergency landing, the ship's Automated Integrity Control system detected an excessive speed and diverted all power to the propulsion systems (and maybe front shields, if your ship has them), ensuring that the ship won't be damaged... but also causing the magnetic anchors to lose enough power that they could be unlocked with just a hard push. The ones that realized this before the crash are the ones who survived. You could turn this into a pretty intense before-the-crash moment, when one of the crew discovers they can detach from the supposedly-locked magnetic anchor and realizes what happened with the AIC and lock systems and what that'll mean upon impact. So they try to warn the rest of the crew but everybody is kind of panicking / too busy trying not to crash and so only a handful of people listen to them... eventually deciding to abandon ship even though they know everybody else will probably die. NOTE: I just re-read your question and realized that you want the *survivors* to investigate the crash. Somehow I thought that it was a different team sent over to investigate and find the survivors. My answer does not fit your question, because the survivors already know what happened :| Ah well. I'll leave it posted anyway. [Answer] ### Fire Without knowing too much about your vessel and tech level, I'd recommend an electrical fire. It's a pain to put out without harming the crew, especially with a huge generator supplying extra energy, and it can easily spread across the ship (since pretty much every area uses power), making it difficult to contain. A lucky few escape in pods, lack of oxygen and toxic smoke kill the rest. After the fire dies down, life support restores a breathable atmosphere, but a lot of wires are fried and several systems, including the reactor's coolant pumps, are now running on emergency power. Whether it's for lack of time, required skills and tools, or simply ignorance of the issue, the survivors do not manage to restore power or do an orderly shutdown before the cooling system fails and the reactor goes critical. [Answer] You have possibilities beyond mechanical damage to the ship. You can get to that situation by damaging the crew only. Specifically, you could imagine a virus (a common trope in SF, I believe Lem has some typical examples). The ship lands well, and the crew is soon dead. Your survivors (no need to be near the escape pods) happen to have a mutation which prevents the virus from killing the host. This is compatible with hard science fiction, for example, people with sickle cell disease (caused by a mutation in a single gene) are immune to malaria. You could just as well have a random, harmless Earth allele prove efficient against the planet's killer. You can set up its frequency at whatever you want, there are alleles shared by the majority of human population and others that turn up once per several thousand humans, so it is easy to have the exact number of survivors you want no matter the size of your crew. If you don't want it to be contagious, you can also come up with an airborne toxin to which some people happen to have immunity, again for genetic reasons. Thus the survivors won't bring it back to Earth if they or their descendants manage to go back. [Answer] Inert gas leak - your body only detects the buildup of CO2. From wikipedia [Inert gas asphyxiation](https://en.wikipedia.org/wiki/Inert_gas_asphyxiation): > > When humans breathe in an asphyxiant gas, such as pure nitrogen, helium, neon, argon, sulfur hexafluoride, methane, or any other physiologically inert gas(es), they exhale carbon dioxide without re-supplying oxygen. Physiologically inert gases (those that have no toxic effect, but merely dilute oxygen) are generally free of odor and taste. As such, the human subject detects little abnormal sensation as the oxygen level falls. This leads to asphyxiation (death from lack of oxygen) without the painful and traumatic feeling of suffocation (the hypercapnic alarm response, which in humans arises mostly from carbon dioxide levels rising), or the side effects of poisoning. In scuba diving rebreather accidents, there is often little sensation, however, a slow decrease in oxygen breathing gas content has effects which are quite variable.[7] By contrast, suddenly breathing pure inert gas causes oxygen levels in the blood to fall precipitously, and may lead to unconsciousness in only a few breaths, with no symptoms at all.[3] > > > [Answer] My favorite scenario for this sort of thing is to have the passengers in some sort of stasis pods. Perhaps it is a form of hibernation or perhaps time is stopped for them. But in either case they are shielded from radiation and protected from violent acceleration (or deceleration). They are probably protected from radiation or contaminants. Sometime after the crash, an emergency timer lets the passengers loose. By this time the surviving crew members have left the ship, thinking that the passengers are safe in stasis. But they don't come back. Perhaps the radiation or toxins got them. Perhaps an alien race? There are lots of scenarios listed in the other answer that could cause the death of the crew. Me, I'd go with a radiation leak. The crew managed to patch it, so there is only a little leak. The passengers would have to think of checking for radiation and then get out of the ship before they die! I'm assuming that they can't go back into stasis because of reasons. Perhaps they don't have the authority to do this. Perhaps they don't know how to do this. Basically they have to escape before they all die. And there are groups within the passengers that don't want to escape because they don't believe the doomsayers. Think of Steven King's "Lagnolers." [Answer] **Spoilers for a near 20 year old game.** *Halo: Combat Evolved* seems to have a similar story. In it, the Pillar of Autumn, a large man made deep space vessel, crash lands on one of the Halo rings, an Earth-like object built by sentient life. Many marine soldiers abondon ship in escape pods, but still quite a few (such as the captain) go down with the ship. The ship remains intact and the crew (or at least a group of them) are captured by the alien alliance known as the Covenant. Later in the game, the protagonist, the Master Chief, realises that the Covenant have released an ancient parasite, the Flood, which consumes all life. It is later found that the Halo ring is actually a powerful weapon which when detonated, will explode and kill all life in a large radius, which is the only way to stop the Flood from spreading (kill the food sources, AKA life). An AI, 343 Guilty Spark, stops the Master Chief from detonating the ring to eradicate the Flood. By killing the Flood, the Chief can save the human race. The Chief decides to use the crash landed Pillar of Autumn to blow up the ring. When he goes back, he is swamped by the Flood, which is a mix of infected humans and Covenant (who boarded the ship as it was crash landing). Chief blows up the Vessel which detonates the ring. --- I'm not sure if you're writing a story or you're just curious, but I believe that the events in Halo: CE are similar to what you are looking for. Also, if I'm wrong in my Halo history, please correct me (I haven't played Halo: CE in a while). [Answer] Depends on the kind of sci-fi and ship. Radiation from the damaged engine/reactor, which unfortunately killed everyone before the auto repair system could fix the problem. Life support critical failure as engine coolant leaks into the oxygen making it toxic. The people in escape pods would be safe because the escape pods are radiation shielded (because they have to survive in space) and were outside the ship. [Answer] I don't know why nobody answered that (or it someone did, I missed it, cause someone even pointed at Subnautica), but to me the simplest solution is... # Water Your pilot managed to make the ship enter the atmosphere relatively unscathed and aimed for a point where the impact would not outright turn your vessel into a fancy ball of crumpled metal. Alas, the landing didn't go as planned, and while espace pods have been scattered during the descent, the shock busted most of the exits, bent the doors, provoked a general black out or whatever do no float that boat. Water will kill everyone very efficiently. Drowning, suffocation for those trapped in an air pocket, hypothermia, starvation, dehydration... Someone stranded in the middle of the sea without the proper equipment is as good as dead. Make us a nice Rose and Jack scene, where Rose dies on her door cause nobody came to pick her up. Your escape pods can provide enough equipment to visit a shallow wreckage (make it a good 100-150, your pilot was just that good), but anyone inside it at the moment of the crash who did not reach for his tuba and pressured suit is 100% dead. (Plus, if you need it, you can make some of them survive. And you don't need to devise a virus that could come bite you later in the story). ]

[Question] [ One of my [favourite stories](http://www.andre-norton-books.com/index.php/worlds-of-andre/individual-novels-by-andre/79-dark-piper) features a major fortress built on the edge of a poorly surveyed wasteland. In that context, the Butte makes sense, as a safety measure against the unknown. Once the wastes are proved safe the garrison stayed in the existing infrastructure not as guards but because it was already there; which makes some sense as well on a frontier world with only a small military and limited funds and manufacturing capacities to build new accommodations. My question is what would make actively guarding a wasteland that is believed to be empty of any threat worthwhile? Basic Assumptions: * the location is physically harsh with supplies having to be brought in from more civilised lands. * the wasteland is devoid of large predators and humans alike. * there is no known source of threat on the other side of the wastes, nor do most consider them crossable in any case. * garrisoning the location is expensive of time, effort and personnel which could be employed elsewhere. * the garrison is maintained over generations but sees little or no action. Good answers should take into account the various *other* duties such a garrison might be involved in and/or reasons to guard a frontier that is observably empty of antagonists. [Answer] There are many possible options; here are some: 1. **Religion, culture, tradition.** You can make people do all sorts of sub-optimal stuff if they think there is value in them, from the favor of the gods to being a virtuous person in general. Perhaps in your society, there is a need for you to serve the barren wastelands to be considered a real warrior. 2. **Education.** If there is *never* any action, what better place to train young recruits? You can even set up military camp for even younger children, depending on how developed your society is. 3. **You can see things there**. This depends on your development. Perhaps you can just see what the enemy is up to elsewhere from wherever your garrison is; perhaps in a more contemporary setting, you can monitor many things, e.g. if they are testing powerful weapons. 4. **As an escape**. People have build ways to escape all the time all throughout history. Perhaps this garrison is in place just in case there is an uprising, build in the most useless place so that people don't bother taking it with force. 5. **To monitor the border the other way around**. If you have a wasteland, then you have a place without law. You need to guard it so that nobody gets any ideas and engages in indecencies where nobody is looking. This goes from criminals hiding to criminal acts themselves. 6. **As punishment**. So you don't like a general but you can't fire them and don't want to slaughter people? Put them and their loyal soldiers where they can't harm you, in the wasteland. 7. **As a reward**. So you have many veterans that have served their time and don't really have a purpose? Any good society cares for their veterans. So, perhaps if they so choose, they can live out the rest of their days on the frontier, playing soldier, pretending they have a purpose, and just in case you need them, you can call them back. And keep in mind, many things don't have a single purpose; you can combine any of them. I'm sure I can think of more, but 7 is a magical number. [Answer] **You are describing all the field training areas I have seen** The army always gets the cheapest land around. Which is the land no one else wants. Which is also a benefit when training soldiers to survive - as the saying goes "train hard, fight easy". Once you have the infrastructure in place, it makes it easier for politicians whose vision only lasts the few years to the next election to say "Oh yes, we'll just keep it going for a few more years" instead of building something new. Which is how you get "temporary" huts built during WWII still in use in the 1990s... There are also legitimate uses for a military garrison a long way from any civilian population or probable threat: 1. Strategic ammunition storage 2. Mothballed military item storage 3. Radioactive waste dumping ground (where else would you want it?) 4. Strategic over the horizon radar or satellite control installation 5. Live fire weapons testing range (of really destructive weapons) 6. Weather monitoring 7. Rehearsal location for operations in a similar environment 8. Sensitive prisoner storage Depending just how unpleasant the facilities are it may be a punishment posting, but that will not be a reason to maintain it long term. [The Vor Game](https://en.wikipedia.org/wiki/The_Vor_Game) describes a base such as this - most staff get rotated in and out on training cycles but there is a core "base staff" that have it as a full cycle posting. [Answer] I have two answers that could explain that for me: # To make enemies believe it's important If you want someone to not see something, you make them watch where you want them to see. Guarding a wasteland can make believe the country is either guarding a powerful/precious resource, or defending itself from a bigger enemy. It can thus let the country prepare itself to surprise attack enemies. # To make sure the population has something to do If you want to keep your population in your hands, you want to be sure they're not bored. So, even if there's nothing to do, you make them work. They don't have time to prepare revolutions. [Answer] # If you don't control it, someone else will There's absolutely sod all in the Sinai desert, well sod all except militants. This is periodically rather a problem for Egypt, so they keep the area heavily guarded. Of course this is a modern problem, but your local trouble makers will accumulate in the uncontrolled spaces and if you don't clear them out then they'll cause trouble for those close to the edge of the territory you do control. You always have to guard further out into the wilds than you strictly want to, just to stop the problems that will come from there if you don't. [Answer] You are forgetting the obvious one. **Someone makes money when the wasteland is defended.** In other words, you have a military industrial complex. Some people are making a good living off transporting supplies, building and repairing fortifications, building infrastructure, or supplying mercenaries to support the regular troops. Those people also have the power or persuasive ability to make sure it keeps happening despite the apparent illogicality. We have to remember that this is a fantasy world, and any resemblance to ours is entirely coincidental. [Answer] Trying not to repeat the excellent suggestions in other answers: **Denial** The location of the base may provide other enemies with a suitable "forward" base from which to assault the kingdom. Additionally should a use be found for the wastes in the future you already have a "claim" on it. **Last resort refuge** Should the main kingdom become at risk of falling the remote base could provide a secure, defensible location to retreat to. The wasteland makes it "secure" from one direction at least and if you can make it defensible from the "Kingdom" side then you have a Helm's Deep-esque bolthole to take refuge in. **Secret activities** Every nation invariably has things it wants to keep hidden from prying eyes - weapons research, training facilities for spies and elite troops etc etc. Where better to do this than a seemingly unimportant base in the middle of nowhere? In fact the more isolated the better! Anyone who shows up has clearly made a real effort to get to that specific location and makes infiltration or spying much harder. [Answer] **It's a prison** for particularly dangerous criminals awaiting trial, or high-value prisoners of war or politics. Isolated by vast distance and treacherous terrain, fortified and manned to military standards: a facility as effective at preventing escape as it is at warding off rescue or assassination of prisoners too valuable to execute. **It wasn't always a wasteland**. Once very valuable, time or catastrophe has rendered the land unlivable. Under the conditions of some treaty, or out of concern over the return of the cause of that catastrophe, the nation owning that land must continue to maintain a strong military presence. **It's not the wasteland, but what lies beneath it, that needs protection.** A rich deposit of some natural resource, a burial ground or lost civilization, a cave network that could be exploited to infiltrate the nation. Or some ancient evil once slain but never defeated, buried far from civilized lands, always at risk of returning for vengeance. [Answer] In addition to the reasons posted in other answers, one obvious one is because it's a vulnerability. Assume the opposite scenario: a large, well off kingdom that has a well defended border, except for the area bordering the wasteland. Where would an opposing army try to sneak in? The wasteland is a large vulnerability because, unlike other border areas that are well traveled by people, there would be relatively little traffic through the wasteland (if any). This means next to no chance of warning that an enemy was coming, unless it was guarded against or watched for. [Answer] One reason you might see something like this in such a seemingly-senseless location could be to simply maintain legal ownership and control of the area. Areas of land that appear abandoned and unmanaged are common targets for squatters (or in the international sense, targets for annexation by another nation). By establishing a significant-enough presence, you make it clear that this area is part of your nation and not up for grabs, and any attempts to take it would violate international law. Another option is that while the wasteland is empty and poorly-surveyed *at the moment*, you have definite plans to do detailed exploratory, surveying, and mapping work in the future. The garrison was built as a staging point for future expeditions, and reinforced just in case something hostile was discovered. You built the garrison but lost funding for the initial survey work. It's cheaper to maintain the garrison and fight to regain the lost funding than to just abandon the whole idea and lose everything. Your garrison's location on the wasteland may also be an unfortunate coincidence. You have two existing bases that need to be able to communicate, but are too far away from each other. You build several garrisons in between them as relay stations. The garrison locations were chosen based on the distance limitations of your communication technology, and this one just so happened to end up in the middle of nowhere. [Answer] Another option among many great answers already **Precious Resources** If the Wasteland Area is known to have something very precious inside it (Uranium, Gold, Oil etc) and the enemies of that state know that it is there. Then it makes perfect sense to protect it, to stop the enemy coming in and taking it. It's well known that "prevention is better than cure", this goes for military campaigns as well. It's better to stop an enemy getting land than it is to take it back from them. If that land had value due to resources within it, even if they are not currently in use or being mined etc... it's a lot easier to hold onto it by, well holding it. [Answer] **Search and Rescue** Simply put, they're there to go pull people *out* of the wasteland when things go wrong. There could be a number of reasons to go into said wasteland - Special resources, a sacred location, a spring that someone says will cure all your ailments, or my favorite: People just going into absurdly dangerous places simply because they can. This garrison is not strictly a military garrison - Although it may have started out that way - but is a good staging ground for SAR teams to go find people. This would also make it worthwhile as a training ground for a lot of reasons, but most of those have been touched on by other answers. [Answer] I am with KerrAvon2055 here. **Training.** I am making a separate answer because I have different reasoning from the land being cheap. The location has following benefits for training the recruits : **Remote from everywhere that matters.** Training accidents? Nobody cares. Accidental collateral damage? Nothing valuable here anyway. Recruits are wanted criminals from the death row (or supposedly already executed ones)? By the time they leave they will be an entirely different person. Your "garrison" is two hundred times as large as it should be and equipped with weapons that are not supposed to exist? Nobody here to notice it. Every recruit with 'e' in their name was sacrificed to elder gods in a blasphemous ritual? Nobody still cares or is looking. The nation is deeply pacifistic and everybody hates the very idea of an organized force of trained murderers? Everybody is not here and never will be. The operation you are training for is totally illegal and nobody will admit to having approved it? Still do not care. I am sure, you already get the point and realize that having at least one location like this is very convenient. I expect major military powers have bases so conveniently remote that "civilian oversight" happens via satellite connection. Just in case What the actual benefits are varies but military planners believe in being prepared for the worst, even when it is unlikely and should be avoided at all costs. **It is an extremely bad place to live in.** Speed and mobility of armies is limited by your ability to supply them. So having superior logistics can be a huge strategic advantage. Or alternately you can just use troops experienced at patrolling a hostile wasteland and let them worry about it. They know how much food or water they need and will not forget to take care of it. They won't complain about any food you provide either. They understand the value of food. And even if you forget to give them food, they will make sure to find some. They will know what is edible and where to find it. They will also know where and how to find water that is safe to drink. And they will never forget water or throw it away when "retreating" unless they **know** water is waiting ahead. So troops that spent some time in your desert will have superior strategic mobility and are much less likely to collapse if forced to retreat away from their supply routes. Entire armies *have* been lost that way. **Patrolling the wasteland is totally and obviously useless.** Anybody can do useful things. But to keep doing something that everybody knows is totally useless and to keep doing it well, that takes discipline. And discipline is the difference between an army and an armed mob. It is also the difference between an army that holds and the one that breaks. These men will not refuse an order to charge an enemy just because it is stupid and might get them killed for nothing. Following orders to do something even more stupid that might get them killed for even less than nothing is how they were trained. **Nobody else is doing this stupid thing.** Yeah, we are special. Different from all the others. None of those sissies has gone thru this hell. Let them break or whine, we never will. We survive and we always will. Basically this will work as a rite of passage and shared experience that will create a very strong esprit de corps and group identity. Such troops are less likely to break or desert. They might end up being more loyal to their commander than their country though, so numbers would be kept low. Which would further make them feel elite. [Answer] **The reason cannot be understood.** <https://en.wikipedia.org/wiki/Absurdism> > > In absurdist philosophy, the Absurd arises out of the fundamental > disharmony between the individual's search for meaning and the > meaninglessness of the universe. As beings looking for meaning in a > meaningless world, humans have three ways of resolving the dilemma... > > > Suicide (or, "escaping existence").. > > > Religious, spiritual, or abstract belief in a transcendent realm, > being, or idea... > > > Acceptance of the Absurd: a solution in which one accepts the Absurd > and continues to live in spite of it. Camus endorsed this solution, > believing that by accepting the Absurd, one can achieve the greatest > extent of one's freedom, and that by recognizing no religious or other > moral constraints and by revolting against the Absurd while > simultaneously accepting it as unstoppable, one could possibly be > content from the personal meaning constructed in the process. > > > <https://en.wikipedia.org/wiki/Waiting_for_Godot> is an absurdist play. The characters wait for Godot, whose nature is unspecified. The necessity of waiting is not explained. There is no explanation of events that will transpire if Godot arrives. It is a trip to be sure. It is a great frustration to concrete thinkers because why? So too your fortress. The reason that it is compelling is that it is unexplained. It might be unexplainable. [Answer] Territory is valuable. There is no territory which is so worthless that it isn't worthless enough so you wouldn't fight for it, fullstop. Even if your entire wastelands are, literally, *waste* lands (radioactive waste) and uninhabitable for the next 5,000 years, you will not give them up. But if you do not guard it, someone else might, or rather will, claim it. You can see examples of this in the real world. China is, if it comes to it, willing to start a war over some petty, unimportant shitholes (my excuses to anyone living on one of these isles by coincidence and reading this) somewhere in the Chinese sea. Which have no real, or strategic, or imagined value at all. Some other nation in that corner fo the world (I forgot which, was it Vietnam?) sold some billion tons of sand to Dubai for building half a decade back, and then found out that the remaining sand just collapses back to fill the hole. It happened that subsequently, some "isle" which was a mere uninhabited sand bank was gone, and by consequence their sea territory got a couple of dozen miles or so smaller. You might say "who cares! this isn't even land!" but this was a huge uproar. Italy gets nothing but trouble from e.g. Lampedusa, it would be the easiest and most reasonable thing for them to simply give it up. But this will never happen. Go back to the 80s (Falkland war), same thing. What's a barren rock at the end of the world which is frozen half of the year good for? Harsh wind, and no sun? But oh hell, you *don't* give up territory, ever. [Answer] **"International law requires a country that claims territory to actively occupy and defend such territory."** That alone is pretty much enough for you. But there is more: # To watch for incoming bombers. That actually happened. [Distant Early Warning Line](https://en.wikipedia.org/wiki/Distant_Early_Warning_Line) was a series of radar stations ("actively guarding") in the farthest, arctic north of Canada and Alaska ("wasteland"). Here's a cool detail: In the 50's-60's, they invented some [absolutely unreal vehicles](https://www.hemmings.com/blog/2009/11/19/54-wheel-drive-the-letourneau-electric-arctic-land-trains-that-put-australian-road-trains-to-shame/) that make "monster trucks" pale in comparison - just to reach and resupply those bases in winter. Unfortunately, large helicopters were perfected about same time and that instantly killed the need of wheeled behemoths. [Answer] Depending on your setting and level of technology... **Radiation** Radiation is a completely invisible but very long-lasting hazard - having guards stationed to protect people from entering such an area would not only work to encourage vigilant guards (who would want a death like that on their hands?) but also greatly discourage trespassing as well! All you'd need to do to allow people access is to give them a hazmat suit, along with proper authorization to enter the wasteland as a 'research specialist'. You'd of course have to control who's allowed in there too - but that's reasonable in areas with high levels of radiation. Also, whether or not there actually *is* radiation in that area is entirely up to you. [Answer] **Smuggling.** You know, because there is no threat and no hostile humans or predators it is a very good route for smuggling things into your land which the native government does not want to have. The idea "Hey, waste land prevents smuggling" is refuted: **Any** desert can be defeated by expeditions leaving hidden caches behind. It may take some time, but finally any distance can be handled. So, this outpost is in kind of competition with the smugglers: The smugglers try to get in, the soldiers tries to prevent that. The reality is that the smugglers normally win: They can choose time and location of their attempts and with the money they can get the best gear available. Those outposts only curb the smuggling to a certain level so that not whole convoys of smuggling goods get past the barrier. [Answer] **The Wasteland is effectively a border. Borders are worth guarding always all the time, no exception.** > > believed to be empty of any threat worthwhile > > > If you only *believe* that then I assume you don't have satellites or planes to tell you, that no expedition came back and that it is uncharted territory at your level of technology. "Nobody would come from there" is perfect for the *Famous last words* trope (I'll spare you the tvtropes link, you know there's one). Great generals throughout history have demonstrated an ability to make the best of areas deemed impracticable, it would behove any military worth its salt to maintain a presence in such an area as part of an advanced warning system. The fact is you don't know what lies beyond. Could be nothing. Could be there's another kingdom watching at the wasteland wondering what's on the other side. Could be there's a great evil centimetering closer unbeknownst to you. You don't know. So you build series of towers for two men to keep an eye on the horizon and make sure the wasteland is indeed void and empty. The heart of that system is a big fortress. It's a big fortress and not some crummy old cabin for a variety of reasons: * Maybe you have something to prove. Maybe you have something to compensate for. Never underestimate hubris as a motor for human ingenuity. * Maybe it's an old fortress built there for some reason, maybe as a starting point for expeditions through the wasteland (the ones that never returned). Or maybe your built fortresses to mark the land and this one just said "I own the place" and now you're stuck with it. * Maybe it is intended to host an army. If you have to send your men to defend the borders, that would be your command post. It probably beats a field camp, and your predecessors probably had a good reason to prefer that. * Maybe it does host an army. As the command centre of your alert system, this is your first response force. There probably isn't enough of a force to kerb any invasion, but even if they get ganked they will delay the enemy just enough. Of course, you don't tell them that. Whatever reason, the fortress is there, and you keep it because you can only impose your law as far as you can reach, and this is proof you can reach this far. **Double employ** Others have pointed in various answers the training grounds aspect of such a location, and I can only agree. It's harsh, which will weed out the weak. It's remote, so it won't interfere with the operations of your dominion. And it if does get ganked as aforementioned, you only lost the most inexperienced part of your army. But again, you don't tell them that. It is also, as others have pointed, a place where you can do whatever you feel like. Dump dead bodies, test nukes, keep alien artefacts, field test new equipment in extreme weather, conduct experiments on live subjects and as always you don't tell them that. The possibilities are endless for less-than-moral activities you can conceal in the middle of nowhere. You might consider it as a prison for your rivals, but just do yourself a favour and throw them in a river instead. You know they will escape and plot against you by assuming the identity of some dashing lad or ugly bum or something. You're only allowed to be that genre-blind if you are the villain of the story. --- In any case, your veterans might view the post as some easy assignment, where nothing happens and they can toy with the new kids, and they get paid for it. Younger soldiers dread it as the end of their career, away from any action, excitement or adventure. In the future, people will find their way through the wasteland and back. We'll know what lies beyond. But the fortress will be long decrepit by then. Maybe your successor will bulldoze it and build a wall instead. But as far as you are concerned right now, it's a point on the map that completes the circle around your territory. [Answer] ## It stops rebels There is a very simple thing that gathers in Wastelands: Outcasts. If a society generates many outcasts that are driven out of the urban areas (you call these urban wastelands "social hotspots" at times), they look for new areas. Urban fringes can become such a gathering place, but in the past, the really shunned people fled to the wastelands: the Australian Outback had been a place where bandits fled to when towns got too hot for them, just like Che had retreated to the mountains and Ho Chi Min to the jungle. People were not around, as was the law, and that allowed these to gather strength in groups, and some to start a rebellion. Wich in turn is a good reason to guard the wasteland: If it is not guarded from the outside, rebels and criminals will gather there. If it is not guarded agaisnt whoever is there, those people already in there will come upon the fortress. For THIS fortress, there is no fully 'friendly' area: just the Hostile wasteland on the one side, and the country, from which any passage into the wasteland is to be prevented. Bonus points: should any aliens land in the desert... well, then we have "illegal" alien "rebels" of extraterrestrial origin facing with a borderguard that will not allow any trespassing. ## It guards a Preserve Even if it looks like wastelands on the first look, it is a natural beauty on the second. It grows rare plants and has some unique small animals and insects. And the people, after exploring it fully (or even before!) have decided, that this ecosystem needs to be preserved for the future. And not just with rangers, it needs to be preserved THAT much against any intrusion, that it is in the duty of the Army to keep it untouched. They are allowed to train at the outer edge of the dedicated area as a little payback. [Answer] ## Greenfield development delayed by bureaucracy The government is trying to sell the land but there has been endless delays and legal challenges, perhaps raised by the people who supposedly don't live there. As a complication, settlement of the land is a popular national issue and no politician would be seen dead suggesting that it can't be settled. [Answer] To protect yourself from what is/might be beyond the wasteland. If something is to come across the wasteland it is preferable to fight in the wasteland than in your more valueable territory. * The wasteland provided no resources to the attacker, in your non-wasteland, the invader can live from the land * The wasteland allows you to defend in depth, "We lost 50 miles of wasteland? Who cares." [Answer] That world's version of the Silk Road passes through the wasteland, and even though you say that it's "devoid of large predators and humans alike", bandits would love to hijack caravans. [Answer] I'll add one more reason to alreayd existing great answers. # Historical reasons. India and Pakistan guard a massive border running through the midst of the Thar Desert (The Great Indian Desert). Why? Because that's how the British Raj divided India and Pakistan, and two countries has been at odds ever since. Because of the enmity, if any country were to lose an square inch of the desert, they would lose face. Thar Desert is not exactly a complete wasteland, but due to the harsh conditions India and Pakistan do have to spend enormous amounts of money to protect these borders. [Answer] They're not "guarding" the wasteland. # The guards are an internal threat There is a fear of a **military coup** from these units. They need to be kept away from the economic heartland of the country at all costs. There are powerful political interests that would use them if they were nearer the capital, and there are even more powerful interests that need to keep them away. The nation still needs these soldiers, or at least polticially can't get rid of them, but the people in power do not trust them. **Guarding some ghost border is a perfect task for them**. This is a survival calculation, so cost is nearly irrelevant. This, of course, may or may not be the "official line". There are a lot of other great answers here, and any would do as an official excuse. This is the reason that the Romans did not want generals in the provinces leading armies into Italy. [When it happened](https://en.wikipedia.org/wiki/Crossing_the_Rubicon) it ended badly for those in power in Rome. There is a (I think fallacious) story that the reason that the [Kings German Legion](https://en.wikipedia.org/wiki/King%27s_German_Legion) were stationed on the Isle of Wight was the stationing foreign mercenary troops on the British mainland was either illegal or just not a very good idea. It may also be part of the reasoning why, historically, the [French Foreign legion](https://en.wikipedia.org/wiki/French_Foreign_Legion) were created to fight outside of mainland France and stationed in Algeria. [Answer] **Religion** There are of a few of us in power who know of peoples on the other side of that wasteland. Though they pose no physical threat, and the number of people who survive crossing the wasteland is extremely low (near zero), we simply *do not* want any potential survivors here. Their mere presence would contradict millennia of dogma and pose a crisis to our power. --- *Note: this question reminds me of current proposals to build a wall along the entire southern United States border with Mexico. Having lived in some and visited others of the hot and dry wastelands in the southern US, I can confirm that there are large swaths of land that come close to satisfying your criteria.* [Answer] Argentina has kept a continuous human presence on Antarctica since 1904. Argentina does not exploit anything there, it does not extract minerals nor farm penguins. I believe the [Protocol on Environmental Protection to the Antarctic Treaty](https://en.wikipedia.org/wiki/Protocol_on_Environmental_Protection_to_the_Antarctic_Treaty) actually forbids any such activity. It could be said that some revenue are retrieved from tourism, but most people there are paid by the government and I am sure the revenue from tourism does not come close to the cost of keeping a presence there. So, why has Argentina kept a presence for more than a century? Most people say it is to ground their **[territorial claims](https://en.wikipedia.org/wiki/Argentine_Antarctica#Argentine_claim)** there. Chile and the UK also have territorial claims on the same territories, but they have a lower standpoint precisely because they have not kept a continuous presence there. **Conclusion**: Some countries do not need any rational reason for keeping a presence on a piece of land, and consider that adding a few digits to their country area statistics is a valid reason by itself. [](https://i.stack.imgur.com/7kOVh.jpg) Argentine Antarctic settlement "Esperanza" <https://en.wikipedia.org/wiki/File:ArgentineAntarcticEsperanza.JPG> Travellers & Tinkers ]

[Question] [ Set in fantasy medieval times, monsters can be seen loitering around the kingdom. People discovered that the slain carcasses of these monsters contain a certain quantity of gold coins. The rest is history. It seems these monsters continually respawn, so potentially there is no limit to the amount of gold being dropped over time. How is it possible for the trading value of gold in such a scenario to remain constant while an exponential increase in the number of monsters over the last decade was reported? Please note that, at the beginning, when the monsters first appeared, it would require an extremely large effort to defeat a single monster. More recently, more effective strategies and weapons against the monsters have been developped, thereby reducing the required effort to a mere fraction. [Answer] **Stuff appears. Stuff also disappears.** There is a large but finite amount of gold coin. When a monster spawns out of nowhere, gold coins to accompany it disappear from their various locations elsewhere and reappear on the monster. The chance of any given coin disappearing is very low, and so only a few people realize that is what is happening. Playing the odds, most of these reallocated coins disappear from large hoards that are locked away and not frequently checked. Persons who find themselves missing a coin assume they lost it or were robbed. The monster did not exist a second ago and so does not wonder where the gold came from; it has always been in its vest pocket. [Answer] Monsters get killed. Gold comes out. A "Hero" takes the gold. They buy a sword. With it, they commit more murder on innocent monster natives. They buy another sword. However, they never sell the old sword. The Smith therefore receives no used metal to use as material source and has to constantly use the gold to buy more metal from lands far away. The gold finds its way to the mountains, where it is finally traded for ore and coal, both of which you need unreasonable amounts of because no hero ever sells their swords. In the mountains, it is given to creatures who promise to get the desired ore out of the caves. They go into the caves with gold. They come out with ore. They are not called monsters here. They're just the workers. Sometimes a "hero" comes and kills them, to present "their" gold afterwards as if it were something to be proud of. Sometimes the monsters rally a revenge attack, but not often. "Heroes" are everywhere. It's quite deadly outside. One riddle remains unsolved. Many "Heroes" have been seen to stand around in places. They don't move anymore. They just stand there. Eternally. Still, they're not dead, so no one inherits their tons of swords and armor. And they don't sell. That's the way it is in computer games. [Answer] The wizards creating the monsters are being paid in gold, which they use as an ingredient in the monster spawning spell. The gold is used but not consumed, so it ends up with the new monster. Because the monsters kill livestock and travelers, and a pre-industrial society is hugely dependent on agriculture, the kings have been emptying their treasury, giving wizards the means to create more and more powerful monsters to put in the rival kingdoms. The kings send knights to kill the monsters in their own kingdom, which get taxed on the loot; plus what they keep they spend that on new armour and at taverns, all establishments also being taxed by the king. So the money always makes it way back to the treasury, and the cycle is complete. There is an arms race going on between monsters and knights. More powerful monsters require more gold to create, but that in turn attracts more capable knights. Monsters are getting easier to kill because the knights are winning the arms race, and they are becoming more numerous as the kings attempt to compensate. It all might change if new innovations in monster magic make the next generation of beasts unstoppable. [Answer] # Monster whomping mostly replaces mining If, *in addition to* your monster-based economy, gold is still being mined the old-fashioned way then it might be less valuable than in mundane history. But if gold mines are much less prevalent, or unheard of, it will still probably be valuable. See, if you take a step back, mining is a sink for a lot of resources: time, money, people. Digging holes into the earth to get at ore veins is expensive and dangerous. Takes a long time. Gotta make sure they don't collapse. Sometimes they do anyway. And the miners have to get paid. Monster whomping as the ultimate source for gold is actually pretty similar when you look at it that way. The monsters probably aren't terribly fond of being whomped for gold. They have jaws that bite. And claws that catch. So - much as with mining gold the boring way - you have to spend money (and manpower) to make money. # As it gets easier to kill monsters, costs go up It's 'easier' because of better technology, large-scale (and thus more expensive) farming techniques, and significantly more skilled wizards and warriors being much more productive. All of this means it costs more. # Abandon the gold standard Mining technology gradually improved, from stone tools to metal pickaxes, to setting huge bonfires (fire that hot weakens the stone) to black powder to modern power tools. So this source of gold isn't really different in kind; it differs only in the details. Now, I'm no economist, but here's an interesting article explaining why the gold standard was [abandoned](https://www.moneyandbanking.com/commentary/2016/12/14/why-a-gold-standard-is-a-very-bad-idea). Basically, gold being the base unit of all currency causes price instability, and is also blamed for destabilizing the financial system as a whole. In other words, these gold coins aren't actually money. They can be exchanged for whatever your world does use for money, making them clearly still valuable. [Answer] # Gold Must Leave the System The only way for a system where gold coins can magically appear requires that there is a way for them to magically disappear and thus be removed from the economy. As such here are several ways the gold coins could be removed from the system: ## The gold coins become an offering to a god The idea is that the gods intentionally put special gold coins on monsters that appear since the gods do not like monsters and want to motivate humans to get rid of said monsters. A person kills a monster and collects the gold coins which can be redeemed through an offering to a god for a blessing. When done so the coins vanish, and they receive either a random or predetermined blessing from said god based on the amount offered up and the nature of the god they are offering to. So lets say a couple are having trouble having a child, they could offer up a sizable offering to a fertility goddess in the hope that she will bless them with a child. Planning on leading a large war against a neighboring country? Better give a larger offering to the god of war than the country you are planning on invading. ## They are used in magic The coins appear when a monster appears which means the coins have certain magical traits imprinted in them. As such they are used as a type of fuel for gate and summoning magic which consumes them. So if you want to use the gate system to travel around the various kingdoms you have to literally use the monster gold coins to do so. As such the trade economy relies heavily on gold coins to fuel the transport system to provide a quick and safe way to transport things across the kingdoms. Want to summon a hero from another world to defeat the current demon king, or send said hero back to the world they came from? Well you will want a mountain of gold coins for that, and sadly since the coins are destroyed during the summoning process if you are unsatisfied with the hero you get there are no refunds. ## Easily transmuted into other forms Alchemists love focusing on transmuting lead into gold, when they should be looking at the reverse. The gold coins that come from monsters are easily transmuted into other raw materials (and conveniently cannot be easily transmuted back into gold). Also if the material being transmuted to is common then the resulting mass increases. So transmuting one small gold coin could yield several bricks or several pounds of stone. In fantasy stories have you ever wondered where they get all the building materials to make those huge castles and walls? Now you know. [Answer] Real world already has answer to your question. Gold mines exist, they continuously pump gold into economy. Yet, gold inflation doesn't happen. Why? Because as economy grows, more and more money is needed in circulation. As long as the supply doesn't exceed economy growth, inflation won't happen. Note that while the total supply of monster coins seems to be infinite, the supply **rate** is limited by the monster respawn rate and human ability to kill them. Only rate has to be limited. But what happens when the gold supply is not enough? Well, letters of credit, collateral and many other financial instruments happen that let people continue trading without actual gold, culminating in fiat money. That's what happened to us, because we didn't have gold-yielding monsters. [Answer] The monsters eat gold ore and thier digestion turns it into coin shaped objects. It takes time for the monsters to eat alot of gold to make one coin, so killing a young monster does not net you much gold. In the past you could kill giant ancient monsters that have had time to accumulate a lot of gold. But now due to over hunting there are only smaller younger monsters that haven't had the chance to eat much gold. That's also why it's now easier to kill them. [Answer] Very few people are actually capable of killing the monsters. Most of them get killed. As a consequence, there is a trickle of gold coming into society. This is economically beneficial because there is, in fact, a serious shortage of coinage. New gold gets snatched up to replace inefficient barter, and make purchases that would have been too pricey if you included the time wasted working out what you could barter. Thus, economic activity increases to the new limit imposed by the amount of coinage, until the next batch comes in. It would help if some of them dropped silver or copper instead. This would help with making change. Increasing small coins can also increase economic activity. If the situation had just changed so that killing can be done more effectively, that's when things start to go haywire. Not centuries earlier, only when the trickle becomes a flood. [Answer] **Monsters run a protection racket** Local farmers and townspeople pay a toll to monsters to avoid being preyed upon. When a hero comes along s/he kills a few local monsters and steals their gold. If the hero is Robin Hood then he gives most of the gold back to the local people. They throw a feast for him and he goes on his merry way. --- The amount of gold in circulation remains approximately the same. There will be lost hoards and gold-ming going on but in total there is not much change. [Answer] Gold is a resource used in magic. I started a story myself where the most powerful mages spend their days with rituals to stem the tide of monsters and invaders. In your case the gold has some sort of connection to the monsters, and even if you dont have "regular" magic you could have the gold end up in the Government's hands and use it in rituals that attempt to stop the exponential (!) Increase in monster appearances. This eliminates gold from the economy. Just imagine how overrun those poor people would be with monsters if they didnt do those rituals... [Answer] **The Monsters were people** A subtle curse a long time ago has produced a terrible new reality. At intervals, a villager will find themselves compelled to wander away from town, find somewhere secluded and transform, body and mind, into a monster. The curse ensures that nobody remembers they existed pre-transformation, it simply seems as though a monster has appeared on the outskirts of town, or in a basement, or attic... If the monster transforms too far away from home, they will wander in search of the familiar, eventually making their way home and bringing them into conflict with the town. The coins belonged to them before their transformation, explaining why the amount of gold acquired is usually pocket-change. A former merchant might well have been carrying more money or unusual items. In this way, the coins are not increasing in number significantly, the villagers are paid for goods and services, and eventually transform into monsters themselves. The gold is returned to the community when a Hero slays them and brings back the gold as loot. [Answer] Let me try a [science-based](/questions/tagged/science-based "show questions tagged 'science-based'") answer. # Biomagnification That is [a real world phenomena](https://en.wikipedia.org/wiki/Biomagnification): > > **Biomagnification**, also known as **bioamplification** or biological magnification, is any concentration of a toxin, such as pesticides, in the tissues of tolerant organisms at successively higher levels in a food chain. > > > In your world there are no gold mines. Gold is extracted from the depths of the Earth by plants through deep roots. Extracting gold from plants gives a very low yield due to low concentration and because 100% pure gold does not form a stable solid (you need an alloy with some other metal). Herbivores eat plants and accumulate gold in themselves. Then carnivores eat herbivores and accumulate it in higher concentrations. Gold is usually [excreted through feces and urine](https://pubmed.ncbi.nlm.nih.gov/385875/) but due to the accumulation process animals have an ever harder time getting rid of it. That is why you get more gold the higher up in the food chain your innocent victim the monster is. As for why it comes in coins, due to an [orthologous](https://en.wikipedia.org/wiki/Sequence_homology#Orthology) set of genes most creatures in this world accumulate gold in their [connective tissue](https://en.wikipedia.org/wiki/Connective_tissue) as alloy discs, usually being 75% gold, 10% copper, 5% iron, 5% nickel and 5% other impurities. These coins are not all the same shape, size and exact composition, but they are easy to reforge into standard realm coins at any mint. Since you practically get one standard gold piece for every raw coin, the gold recently extracted from monsters is also accepted as currency and tender in small villages and other settlements. --- You may be wondering how the economy manages to be stable this way. Remember how I said there are no gold mines? Monster hunting replaces that activity and gives out the same output over time. However in your world the economy is growing at the same pace as gold becomes available, so things even out. [Answer] **The monsters respawn at almost the exact pace the economy grows.** (because... Monsters depend on some waste of the tax administration internal rituals? Monsters multiply exponentially just as an adequate economy does... most of the time? Monsters are proportional to the number of the adult population? Each monster is a virginity lost somewhere around?) --- This is (minus magic and plus a lot of politics) how modern ("fiat") money in a more or less well-behaved financial system work. The economy grows, so does the money mass in just a bit faster pace. Each year you get more goods and services at almost the same price. You need just a tiny bit of healthy inflation, or the people stop spending and the economy halts. [Answer] # Humans Die Too! I mean, why do people bother killing the monsters? We don't go around killing random deer and turkeys in a genocide of bloodlust, because they are not considered a threat. The villagers attack monsters because *the monsters attacked first*. They are a clear and present danger. And when they kill a villager, they scavenge for shinies, because that is their instinct (and the same instinct which causes dragons to gather hoards of treasure). They don't kill for food...they kill for shinies, and they have learned that villagers (and especially heroes!) are a good source of shinies. Unfortunately, the humans have been getting stronger and smarter about fighting monsters. But the monsters have the advantage that they do not need to reproduce in the slow manner of humans. They can just spawn, seemingly out of nowhere. But in order to obtain gold, they must participate in an attack on hapless villagers. # Sometimes They Don't Die Because the monsters are not hungry, they don't usually eat their victims. They just scavenge for shinies. This often leaves villagers alive, but bankrupt. The monsters are mindless thieves, though they would never describe themselves that way. Sometimes, the villagers realize it is better to play dead, with a bag of shiny coins in their outstretched hand, than it is to fight off monsters with a pitchfork and scythe. This way, the humans live, but the monsters acquire gold. # Monster Society Monsters don't have a "society" or "economy" the way humans do. They mostly eat animals, just like the humans do (which explains the grisly carcasses which can be found from time to time). However, they have a kind of proto-society/economy which revolves around shinies. They collect them. The bigger monsters can attack richer humans, and thus gather more shinies. Smaller monsters can only prey on weak villagers, who offer a pittance of shinies. Sometimes, bigger monsters will earn prestige and followers by giving away token shinies to smaller monsters, who then go on raids with them. This is how some monsters end up with shinies even though they never attacked a human. This is how monsters left behind to defend the burrow/den/whatever end up with coins, even though they are glorified babysitters/guards. Every monster wants shinies. Every monster gets shinies. But the total quantity of gold is perfectly normal, and only grows with mining, and shrinks when a gold-laden ship founders and sinks to the bottom of the sea. [Answer] **The Value of a Good Logarithm** The amount of gold available remains constant, which means as the number of monsters grows exponentially, the amount of gold derived from a monster decreases logarithmically. **Nullify Anti-Monster Combat Skills** As the monster population increases, so does their combat acumen and strength. In other words, it's harder to kill the monsters as they grow in numbers. This offers a motivation to deal with the monster threat ASAP to avoid the obvious side effects, which also has the effect of keeping the amount of gold somewhat constant. In short, it nullifies the increasing experience and ingenuity of your monster-killing populace. **Taxation — The Enemy of All Capitalism** Equiping, feeding, transporting, and entertaining troops is WHOMPING expensive! As the monster forces increase, so must the cost of combating them. This expensive endeavor not only justifies bureaucratically complex governments and a sizable military-industrial complex, it also requires a large and complex tax collection system (\**cough\* IRS \*cough\**) but also a large advertising campaign to keep the once-gold-rich population content with constant taxation. **Forget "Buy local!" … Buy Overseas!** You definitely don't want to harm your economy! So buy all your swords, armor, medical supplies, etc., from your neighbor! Ruin ***their*** economy! Exponential growth in monsters and consequently exponential growth in gold? Hah! Who cares if gold is worth pennies-to-the-ounce among your most hated enemy! **You're Famous!** Of course it's incredibly important that your people realize that their safety and security is a blessing from you and only you! Make sure they know this by having giant, beneficent STATUES made entirely out of GOLD in every city! Maybe even two! Put one at every crossroads! Then, of course, to protect your economy, you need to hire guards whose only duty is to be sure NOBODY defaces a statue! **The Bottomless Pit is Not a Legend** Finally, consider having the Bottomless Pit in your kingdom. Not only is it a *great* place to dump all those monster corpses (they stink, you know!) but it's a great place to offer *sacrifices of gold* to [Glarnak](https://worldbuilding.meta.stackexchange.com/a/3789/40609)! The sacrifices are, of course, mandatory and ensured by a large, well-paid police force. [Answer] Most of you adventurers have not taken any classes in Monster anatomy, just hack slash their way to a win. If they had they would discover that gold typicality is always found in the stomach of the monsters. They get there by eating less able villagers, adventurers, and other monsters. The monsters use them like gizzard stones in birds. The action of stones in the stomach helps grind and break up food, making digestion easier. The monsters will also happily eat copper and silver coins, but since they are less noble metals they slowly dissolve in the stomach acids. So that is why monsters want to eat food (people) containing gold. That is why you don't get rapid inflation in the price of gold. Anyone who collects enough of it gets eaten, taking it out of the money supply. Also gold is quite a lot more valuable than silver and copper and the ratio of gold coins to silver and copper is fixed, most people only trade in copper and occasionally silver and those coins are permanently being removed from circulation (by acid) so the two forces mostly cancel each other out. [Answer] There is no gold in the sense you and I would mean. There is a metal. When that metal is near a monster, it converts into ever more pure gold. When that metal is farther away from a monster, it slowly turns to lead. The rate is low, but not zero. So where do the monsters get the lead? [Lead acetate](https://en.wikipedia.org/wiki/Lead(II)_acetate) is was a sweetener. Maybe monsters add it to their tea and coffee? Maybe it is a mineral distributed in the soils of their homeland. Maybe its dissolved in the waters of their homeland. (We'll put mineral and water together and just speak of water subsequently; but remember that the source could be either or both.) Whatever the source, it slowly accumulates in their biology. Of course, since it is then close to a monster, it starts to turn to gold. Perhaps this transmutation is some ancient adaptation to allow monsters to survive in this region having these poisonous waters. If this source of lead is exhausted, if the monsters are taken to new lands, or if illness or injury causes the monsters to stop absorbing and storing the lead, the amount of subsequent gold decreases. I hear some smart guy is building a monster zoo with lead lined cages... Why aren't we swimming in gold? First, there is only so much lead in the water at any one time. Second, the lead has to accumulate for a time to convert to gold; if the rate of "collection" increases, the mean gold per "target" decreases. Third, rich guys have learned that they can keep their treasuries sparkly if they keep monsters in the treasury; they're captured and kept in the treasury as guards and then their internal gold is collected when they die by other means. But these captured treasury guardsmonsters no longer have access to absorbable lead, so the amount of gold is pretty much fixed at the time of capture. So, there's just less free range gold for heroes to collect. [Answer] **1. You need a gold sink** Some way of getting gold out of the economy. Video games have a very similar situation to yours and some of them such as RuneScape have created degradable items that must be repaired by NPCs at a [high cost in gold coins](https://runescape.wiki/w/Noxious_scythe#Repair_cost) as a partial solution to this issue. A real-world analogy to a game developer would be a government. Hence my next point... **[Progressive Taxation](https://en.wikipedia.org/wiki/Progressive_tax)** From wikipedia: > > A progressive tax is a tax in which the tax rate increases as the taxable amount increases. > > > Despite having an endless supply of gold available, monster slayers might stop the hunt when they can only keep 20% of the harvest and decide to go on vacation instead. The king in power is a hoarder, and keeps all the taxed gold in a large chamber for him to gaze upon. The taxed gold is effectively taken out of the economy. **Loss at sea** The most profitable monsters live on islands far away, and your monster slayers have gotten greedy. As they fill the ships beyond capacity with gold to voyage back home, more and more of them start to sink to the bottom of the ocean. Another possibility is loss at sea through trade. As one king becomes much richer than another far away that might not have as many monsters, he realizes that the purchasing power of gold in other kingdoms is much higher. An increase in sea travel leads to an increase in lost ships. **2. Limiting factors** You may also have ways of limiting the amount of gold that gets introduced to the economy. Some of these may be: **Lack of good monster slayers** Slaying dragons cannot necessarily be self-taught. And since it is such a profitable venture, the few who know how to do it do not want to waste their time teaching others. Since very few experienced slayers want to take time off from slaying dragons to teach younger adventurers how to do it effectively, the majority who attempt to follow this career path are inexperienced and unsupported. They end up dying in the first few months to a year. Even though there is a theoretically infinite amount of gold to be obtained, very few people are actively hunting for it. **People for Ethical Treatment of Monsters (PETM)** Activist groups rally and lobby against the senseless mass killings of monsters and your greed. They slow down your efforts. **Natural Resources Ministries** The king does not want its population to become wealthier than he is, and puts a limit on the amount of monsters each person may kill. A person may need to purchase a permit to hunt specific monsters and may have a limit on the amount that can be killed per year/season. **3. Economic reasons** This isn't my field of expertise and other answers cover the subject, but here's an idea: **Growing population** Even if the amount of gold in the economy increases, if the amount of gold each person has remains stable, the purchasing power of gold also remains stable. [Answer] If the cost of killing a monster is equal to the value of the gold you can extract from it (including the killer’s profit, the cost of the killer’s training, any operating cost and adjusting for risk), the price of gold should remain relatively constant over time. [Answer] It is a matter of perspective. From a "player in a RPG" hero point of view, the monster apparitions increase, as does the difficulty involved in slaying them, and also, yes, the gold coins received. Still from a non-player character's point of view, a non-hero regular merchant/ soldier etc. roaming about, the monster situation is curiously the same. It is the hero who travels and searchers for more demanding /rewarding fights with increased gold wins but also expenses as his/her power grows. So it is not that the monster numbers keep increasing since, well, forever -- there may be crises but also long periods of no monster activity at all -- but during crises, the hero is needed to travel and confront the appropriate leveled threat. It is a given that you do not, as a god-tier hero, go on an expedition to eradicate, say, plague rats when farmers with pitchforks and leather vests are sufficient, nor are you suicidal as a beginner would-be hero to go and try to slay dragons when you're basically a courageous farmer. More than that, if the fantasy world allows it, you might not be the only hero, or the mightiest yet, or in the best party possible, etc. There may be others that "play the same game" but at their own levels, carrying appropriate tasks. So no, the overall gold does not increase exponentially- you, as a hero, just happen to see stronger and stronger foes and are awarded more gold as you win- because you need to- maintain gear, feed party and self, buy new gear etc. And so does everybody else in the adventuring business. For you there might seem to be an increase in the number of monsters you fight and the gold you make (but also spend) but for everyone else there is just a fluctuation- after you drive out the dragon, lesser monsters will emerge, and lesser heroes will come to collect... and so on. Moreover, the fact that you find gold on monsters can be thought to be only a hero's tally of the reward that the officials/hunters guild/adventurers guild/king/whoever sent you on the quest will pay you for slaying said monster (apart from intrinsic fur and bone value etc) - more like public safety benefit tax or something. [Answer] Other items ALSO drop. Due to this, not only is there more gold every day, but also more of every other material. Trees respawn, chickens respawn, fish respawn, etc. Thus, the quantity of goods stays in balance with the quantity of gold. If for example in year x+1, 10% more gold is dropped than in year x, but also, 10% more wood, 10% more materials, 10% more fish, 10% more potions etc, then it should remain in balance. (This is often the case in MMOs as well, if fishing is super profitable, many players fish until it is no longer as profitable, then player move to other means, such as mining, woodcutting, hunting, potion making etc) In general, any product that is under- produced, ends up becoming more profitable, and this brings more producers back to that skill or profession. Interestingly- deflation is even possible. As people approach the limit of monster slaying rate (determined by instantly killing a monster on respawn) the gold entering the economy hits a hard cap, and if other resources, like respawning trees, are more plentiful, then the ratio of gold to wood would mean that gold would deflate. [Answer] I will not provide you with a direct solution but help you formalize this problem. Your world is creating a constant stream of new gold pieces (gp). This is called a source, in your case is monster-slaying but it could be anything else. In order to have your money to not devaluate, not inflate you need a sink which is what most answer here propose. a sink is a way to make money disappear. thus the net balance of money is set such as it neither win or loss values. You can have several sinks. you want something on the line Source + Sink = a little more than 0. To compensate from the variation of your economy and your population. as additional Sink that those already proposed here: * God demand gold sacrifice the GP is disposed on the alter and disappear with pyrotechnic effect in the god plane. * some magic stuff or spell consume gp when use or cast. In addition to sink your money could be artificially set to match a rare resource, like adamantium. (We used a gold equivalent not so long ago). example 1000gp is worth a gramme of adamantium. Which will prevent it from changing to much if the absolute adamantium value does not change. [Answer] **Trade with a distant empire drains gold from the system.** During antiquity, Europe, North Africa and the near east had an ongoing problem with gold and silver being drained from the economy by the silk trade and other eastern-oriented trade. They produced few goods that could be exported profitably to India and China and as a result continually sent precious metals east in exchange for goods. Your economy works fine if there is another part of your world that lacks gold-spawning monsters but produces goods that are in high demand. Excess gold will continually leak from the local economy to the import economy. [Answer] In our world, gold is not actually used up. Whereas in magic world, certain powerful magical processes - such as those granting longer life or prolonged youthfulness in particular -- use up gold at prodigious rates. Therefore, like oil in our world, a steady and rising production is needed to avoid a shortage. If no more gold was forthcoming supplies would be used up rapidly and alchemists would need to find an alternative source such as transmuting lead. [Answer] Two options exist in the real world: 1. **Gold is perishable** so it has a limited useful life. Either it turns to lead (or straw - as happens in alchemy) after time if not spent, or it possibly is radioactive and decays. In the end the amount of gold in circulation is constant. 2. **The world is not a free market** So prices are fixed by a feudal government. All goods and property are owned by the feudal lord (which is actually true even in capitalist societies, through eminent domain). This means that the weapon smith is simply not allowed to set his own prices based on demand. We see this happening today under the pandemic. People could almost charge whatever they want for a face mask because everyone needs one, even thought they are incredibly cheap and easy to make. The government prevents price gouging for vital goods. Hotel rooms in hurricanes are another example. So in your world full of monsters, if you don’t have a sword, you die. A sword is a vital commodity, therefore the government mandates a price cap on these essential goods. The price can’t change. Same goes for wood to build your shelters, groceries and food items, armor, etc. [Answer] ## The Ruling Class is taking the gold out of circulation The sensible government is well aware that if the price of gold collapsed, their society's ability to control the monster population would also collapse, along with their whole economy. The skilled monster hunters would go broke and leave, dooming the kingdom to increasing levels of monster attacks. So, they heavily tax everyone except the monster hunters and then secretly dispose of excess gold somehow. By doing this they maintain a system that is just managing to keep monster populations stable, or is even gradually reducing them. [Answer] ## When humans die all the gold they own disappears. When a monster dies it produces gold. When a human dies All the gold they own disappears with them. Once people realize this happens they will take measures to mitigate it but some losses will always occur. Then net amount of gold will still increase but there will always be a drain of gold being lost as well. this will allow the economy to growth without getting rampant inflation. It also give some control of the gold supply, need more gold kill some monsters. Even better it self regulates inflation If people start hoarding or the value of gold drops, more gold is lost when people die (because they have more) so inflation can't get to out of hand. [Answer] ### Evolution favours non-gold-producing animals Consider [elephants](https://en.wikipedia.org/wiki/Elephant) and [ivory](https://en.wikipedia.org/wiki/Ivory). When killing an elephant took a great effort, you would generally have to wait for them to die naturally. As a result, ivory from elephant tusks was highly valuable and rare. Ivory from other species (whale and walrus tusks, for instance) was mainly used instead. When Europeans arrived with guns, killing an elephant now took relatively little effort. Elephants were slaughtered en masse for their tusks. Elephant tusk ivory remained (and remains) rather valuable, but it became less rare. With large-tusked elephants being killed for ivory though, this imposed an evolutionary pressure on elephants. African elephants in some areas now [have smaller tusks, or may be entirely tuskless](https://www.nationalgeographic.com/animals/2018/11/wildlife-watch-news-tuskless-elephants-behavior-change/). If or when poaching becomes less of a risk for elephants, we will discover whether these elephants revert to having tusks (given the evolutionary advantages in competition for a mate) or whether they become the start of a distinct new sub-species of elephant. In the case of your monsters, the amount of gold within each monster may be something that "heroes" can work out, because you don't want to risk your life trying to kill a monster for no reward. Gold is relatively heavy, so it seems likely that it would affect how the monster moves, or there may be other visible characteristics which could be picked up. "Heroes" would attack gold-bearing monsters, but leave monsters alone which they knew would give no reward. With gold-bearing monsters being preferentially killed, it is not just likely but ***inevitable*** through evolution that surviving monsters would develop so as to not store gold. This might otherwise be a genetic fault which has disadvantages for the monster - perhaps it would make their digestive system less efficient at processing food, for instance - but as with elephants and their tusks, this would be vastly outweighed by the advantage of actually surviving long enough to reproduce. Which is morally correct, of course. If you kill the goose that lays the golden eggs, you shouldn't assume you'll just be able to find another similar goose. [Answer] The gold coins would need to plausibly generate from the living body of every monster, then only being available for extraction in the corpse of the creature. This means that these coins must be organic in some sense. Perhaps the heart or brain of the monsters naturally produces a small quantity of gold throughout the monster's lifetime. This raw, unrefined gold ore would then be present in the monster's veins and arteries or alternatively, the monster's hemocoel if it has an open circulatory system. The gold would then need to be prevented from being expelled in some way, such as the monster possessing an excretory system that only eliminates lighter elements, leaving the gold behind. Based on the monster's anatomy, the gold could collect in some vacuous, space and naturally conform to a coinlike shape over time. The only way I can see to maintain the value of gold present in the economy is to have these partially organic coins decay eventually, possibly leaving behind a subtle gold residue which for some reason is of negligible value, perhaps because gold is extremely common in the environment of this fantasy setting. [Answer] Just have the AMG (Average amount of Monster Gold) be like Minimum Wage is in the US. When the Minimum Wage goes up, corporations assume that since people are (theoretically) getting more money, their products should cost more so they get more money themselves. In other words, as monsters become easier to slay and the number of gold coins increases, there is an equivalent increase in the cost of goods. The price of gold will therefore be constant relative to the goods it is used to purchase, even though there is more gold coins. ]

[Question] [ In the underwater survival game [Subnautica](https://en.wikipedia.org/wiki/Subnautica) there is a fish called **Crashfish** that, upon being too close to it, swims out of its plant to chase you and eventually explode. The explosion leaves no remains of the fish, it is completely vanished. The plant in which the Crashfish lives is called a **Sulfur Plant**. As you can read on its [Wiki](http://subnautica.wikia.com/wiki/Sulfur_Plant) page there is no mention of the plant having anything to do with the Crashfish other than that it just lives in the plant. How can a fish that blows itself up prosper enough to reproduce on a grand enough scale to persist as a species? [Answer] **Eusociality** Like bees, the fish are eusocial. They live as colonies with the majority of the individuals being asexual workers. The exploding fish are a specialised caste of defensive individuals that sacrifice themselves for the good of collective. Possibly, they are a later end state of individuals from other castes which transition to the "exploding" caste when they start getting old and sick. [Answer] When the female fish blows up, the explosion sprays all of its fertilised eggs and some stick to the animal that triggered the explosion, or the thorn apart pieces of flesh, and gain their nutrition from it later. If another fish eats the meat, no problem, they will just continue their existence as parasites within the animal's intestines and leave through evacuation once they are big enough to survive on their own. The male of the species might not even do this blowing up thing, it might look entirely different and might not live in the same plant. [Answer] **Salmon** What do salmon do? They are born... grow up... drop eggs/sperm... After which, it doesn't matter because they have already seeded the future. **Cycle of life** Make the fish have the same basic life cycle: Birth. Growth. Procreate. BOOM! Once the eggs are fertilized - most likely in/around the plants that they later protect... there is no reason for them to be OTHER than protecting the plants. [Answer] The blowing capability is a recessive feature carried by b allele, meaning that only individuals having the bb pair in their genome will blow up. Bb or BB individuals will not blow up, but will benefit from the protection offered by bb individuals and will be able to transmit the feature to future generations. The individual will perish, the species will thrive. [Answer] **Although the answers here are all logical, I would like to throw in another concept: animal learning.** Some plants are highly toxic and kill animals eating them. This doesn't directly protect them, as animals only realize they can't eat that after the plant has been eaten. This protects them because animals **learn** that they can't eat those. ### A more animalistic approach: For information, what I'm gonna say here comes from a book (actually a light novel: "Kumo desu ga, nani ka?") and has no example in our world. In a book I read, there is a tribe of apes that live amongst strong monsters called "revenge monkeys". Those apes are not strong by themselves, but when one of them gets killed, all the other in a 20km radius will try to avenge him, whatever the cost. As a result, the other species learned not to mess with them. [Answer] I really liked [Jack Aidley](https://worldbuilding.stackexchange.com/a/103149/42101) and [L.Dutch](https://worldbuilding.stackexchange.com/a/103142/42101)'s answers. However, I just wanted to add one more possibility: **[quorum sensing](https://en.wikipedia.org/wiki/Quorum_sensing)**, whereby certain behavior is triggered by the density of a certain external stimulus. In the case of the Crashfish, each fish constantly ~~poops~~ releases a hormone in the surrounding water, a bit like humans may release chemicals perceived as *body odor* by others. When the local concentration of the hormone in the water becomes higher than a certain threshold, the fish triggers a hormone response called the *self-ignition* response, enabling the explosive behavior. The explosion clears the local area from the hormone, thus having a "sedative" effects on the nearest Crashfishes. In practice, if the colony is too successful, then there will be more hormone in the water, and there will be more explosions, taking down the population number. If the colony is not particularly successful, it may happen that no crashfish will blow itself up. Hiding in the plant may just be a intermediate response to high hormone concentration, whereby the fish tries to find an area, by instinct hiding in the plant, with reduced hormone concentration before triggering the self-ignition capability. [Answer] There is precedent in the animal world. There are [many types of creatures in the deep seas that glow](https://phys.org/news/2011-12-ocean-bacteria.html) to *attract* predators so that, when eaten, the predators themselves now glow and they in turn can be eaten, disposing of the predator. The biological cost to individuals is high, but favorable to the species as a whole which is always the calculus of nature. [Answer] I know you said there's no mention of the fish being related to the plant, however, it seems likely to me that the fish leaves spores after explosion that will cause a plant to grow. It's highly possible that the "fish" part of "Crashfish" is a misnomer, and it's actually technically part of the plant. [Answer] It is as simple as a matter of relative population sizes. In a balanced ecosystem, prey has to exist in large numbers lest they disappear, while predators should be comparatively few lest they exterminate. But if **most prey individuals blow their attackers**, they simply shift the relative numbers in favor of their colony as a whole. [Answer] It is the same as how wasps go out of their way to sting you but they prosper only because we do not mess with them. One fish blowing up would not mean much as long as it has already given birth to babies, and this species would have no natural predators because of well the exploding. [Answer] My honest guess is that it would do that in order to protect its offspring ... I imagine that it already laid its eggs in that plant and that no animal is stupid enough to try and approach a kamikaze fish even the little ones ... you don't want to have a few of those explode in your mouth or stomach do you now? Basically 1 dies to send a message to the rest of animals , we are crazy run for the hills . [Answer] There is a species of explosive ant in Malaysia, [Colobopsis saundersi](https://en.wikipedia.org/wiki/Colobopsis_saundersi): > > A worker can explode suicidally and aggressively as an ultimate act of defense, an ability it has in common with several other species in this genus and a few other insects. > > > So this is alredy a thing in nature. So to answer the core of the question: > > How can a fish that blows itself up prosper enough to reproduce on a grand enough scale to persist as a species? > > > There is no problem in a few fish exploding, as long as enough fish don't explode. **This is not different from non-explosive behaviors**. When a bird eats a distinctively colored butterfly and gets sick enough to puke the butterfly after that, the butterfly is already dead, but the remaining population is safe (from that particular bird). ]

[Question] [ **Background** I want to burn down a city completely. Nothing must remain, ashes to ashes, dust to dust. Even though I'm a supernatural being, I want this to happen in a natural way. I also want the destruction to not leave any traces that can be used by humanity 4,000 years later to identify what exactly happened. The event may however leave traces that make them guess what happened, but it should definitely not lead to the exact cause. [](https://i.stack.imgur.com/W3gc6.jpg) **Details** * Burn down a city completely (read: destroy, I like fire however). * The city is situated above sea level in a semi-arid climate. * The event may not leave any clues. This means that humanity 4,000 years later cannot ***exactly*** identify what happend. The destruction may however leave traces that make people wonder about what exactly happened. The main point is that the city itself should become a legend, meaning that the destruction site should not leave any traces that can prove the existence of the destroyed city. It's however fine if people get to know that some sort of nature disaster happened, but preferably they won't exactly know what type of nature disaster. * Time of the event: 2,000 B.C. (approximately). * Preferably the destruction happens within 24 hours. * Preferably the destruction method can take down a city that is built mainly with rock and clay like substances. **What are my options? Any natural disaster that can be of use? Is this even possible in a natural way? Please be creative.** I was thinking about *"fire from above"*, but a meteorite impact would be visible for more than 4,000 years. > > **Edit 1:** I removed the following requirement, to make more answers possible: > > > * The area is not volcanic active or seismographic active. > > > **Edit 2:** The amount of answers and comments is overwhelming, thanks! I have rewritten the requirements/details to make things a little bit > more clear. I also added the word "preferably" to two of them, meaning > slightly more answers should be possible. Just keep in mind > "preferably"... > > > *Also note that this question was first talking about two cities. I changed this to one city because: if it works for one city it will probably work for any amount of cities.* > > > [Answer] I have much academic experience with some of this, especially the second part of your question. I'll address a few different sides of things. The most drastic way I can think of that could ostensibly be caused by some natural occurrence would be a low altitude meteoric air burst similar to the [Tunguska event](https://en.wikipedia.org/wiki/Tunguska_event). Such an event would cause a lot of surface damage without necessarily leaving a crater or other easily identifiable visible mark. As you've removed your restriction against volcanic activity, you might consider [pyroclastic flows](https://en.wikipedia.org/wiki/Pyroclastic_flow) as one possible means of destroying your city, with conditions less like those experienced at [Herculaneum](https://en.wikipedia.org/wiki/Herculaneum) and more like those at [Saint-Pierre](https://en.wikipedia.org/wiki/Mount_Pel%C3%A9e#The_main_eruption). However, natural disasters on a city-destroying scale generally leave telltale signs behind. So if the air burst notion doesn't fly for you, and if you truly need it to be impossible to determine what caused a city to be burned to the ground, I would suggest staying away from something like a volcanic eruption and perhaps finding a more mundane way to explain a massive fire. Something as common as a bolt of lightning could very well start a fire that spreads out of control, if the conditions are right. Not very exciting, but it could get the job done. Now specifically to the second part of your question: Many large settlements have been totally wiped out by fire. What you're describing, though, where literally nothing is left 24 hours later but *ash,* is somewhat more problematic. When something that big burns down, it can leave pretty noticeable remains for a very long time, especially if the area is relatively undisturbed. (Researchers can identify things like tiny campfires older than the time frame you're describing.) But, say, if the area was abandoned after the catastrophe and later re-inhabited, then evidence of the event could be very difficult to come by. Disastrous episodes or not, people tend to tear down the old and rebuild over it with the new. Additionally, with whatever you do find, it can be problematic knowing whether it was disturbed or altered in some way by more recent inhabitants, adding to said uncertainty. Likewise, as others have pointed out, water is great at eroding evidence, but it still can leave some traces, which you may find desirable (i.e, your stated "clues that make them wonder" aspect). The nature of the flooding itself, such as whether it's a permanent feature (e.g., a lake), etc., can make a lot of difference. The evidence that is left behind for people to find might depend largely on the nature of the flood itself. (On a related note, you mention your city is above sea level. If that's not a hard requirement, it would be simple to explain a flood if your city was below sea level.) I won't belabor this here; if you want more information specifically about this particular facet, just let me know. Letting nature run its course will help obliterate much of whatever evidence is left. A semi-arid climate may not be as ideal for obscuring evidence as, say, a jungle, but weather effects and natural geologic processes will certainly contribute to eliminating material remains left after the city's destruction. If ultimately your chief concerns are to totally annihilate a city and have it be hard for people later to determine exactly what happened, then if you can relax the requirement on a complete "ashes to ashes" situation, you can in fact achieve a realistic scenario that meets your goals: Even if you don't completely demolish the city to the point of literal ash, you can easily meet your requirements for not leaving many traces behind by simply having the area be re-inhabited by people later, or having the site be covered by water. Flooding aside, allowing nature to run its course will generally do much to cover the catastrophe's tracks. --- **Additional Info -** Regarding your question specific to an air burst (moved from comments): With Tunguska, the object causing the explosion itself left virtually no traces behind. It was essentially completely vaporized. Even in-depth analysis of the soil doesn't really tell us much. So, if we're talking about finding any tell-tale indicators of something like that in the archaeological record thousands of years later, in a semi-arid climate, with all the natural processes present there? Then yes, it's extremely unlikely we'd be able to tell anything about the object that exploded, per se. The one thing I wonder about is the blast pattern it might leave behind. But as long as the city isn't sprawled out over a ridiculously a huge area, most of the force of the blast would impact structures vertically rather than horizontally, and that's a plus. If the building materials are things like mud bricks, I'm thinking things could be pummeled so badly by the blast that in 4,000 years, you'd be left with little more than rubble to dig up, with the occasional large chunks. Things further out from the center will be affected less, but on the scale we're talking about, pretty much nothing would be left. And, yes, there would be *lots* of fire. Anyway, to sum up, without totally obliterating the surrounding geography with an obvious crater, I think people might suspect the city was demolished in some way, but it'd be near impossible to tell anything for sure. If you want to toss in some extreme weather in the aftermath, I'd lean toward tornadoes, to further muddle things up. [Answer] * Rock and clay don't burn well, leaving you with a lot of dressed stone lying around to say there was once a city here. * Fire from above implies volcanoes, as we learned from Pompeii, that's actually a great way to preserve a city so that 4000 years later we know exactly what happened, down to what specific individuals were doing when it hit, so that's out. * Semi-arid means you can't dump a forest over the top to hide it but also not dry enough to blow a desert over it. Your best bet is to level the city and then rebuild a city on the same spot. There's nothing like thousands of years of human activity for masking human activity and if the features that caused the original city to be a place of note still exist, someone will rebuild in the same place. As an example of this, look at [Har Megiddo](https://en.wikipedia.org/wiki/Tel_Megiddo) (a.k.a Armageddon), it's an ancient city, built on an ancient city, that was built on an ancient city, etc. The further down you dig the older the city you find, the continuous building of cities on the same spot creates the [tel](https://en.wikipedia.org/wiki/Tell_(archaeology)). The location provides control over the land trade route between Europe and Africa so it was always a good place to build. We know there were consecutive cities on that location for thousands of years, but we don't really know what happened to each one. Note the amount of "citation needed" and "dubious - discuss" across the entry. [Answer] How about a catastrophic flood? Have the city built on a large river. A landslide further up blocks the river and causes an enormous lake to form (also cutting off water supply to the city causing hardship for the inhabitants). When the dam fails...it *really* fails and a wall of water rushes down the valley wiping out the city and thoroughly destroying it, leaving only oddly shaped rubble scattered along the river's path. <https://en.wikipedia.org/wiki/Gohna_Lake_dam-burst> Or for something even bigger have a glacial-ice dam containing an even larger body of water. That would fail with no warning (not even a drop in river level) and is a genuine threat to some areas in the real world from climate change. <https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/100/7/1054/182167/the-formation-and-failure-of-natural-dams?redirectedFrom=fulltext> > > The most dangerous are lakes formed in main valleys dammed by tributary glaciers. Failure can occur by erosion of a drainage tunnel under or through the ice dam or by a channel over the ice dam. > > > For a concrete description of how much damage these sort of events can cause check out this: <http://abcnews.go.com/2020/story?id=2918360&page=1> > > The water crashed down the valley, sweeping trees, rail cars and entire houses in its path. By the time the 20 million tons of water reached Johnstown, it was carrying even more debris. The mass hit the city, flattening everything in its path, until it was stopped by an immense stone bridge at the far end of town. The stone bridge held, but created a disaster of its own. It acted like another dam, causing the water to back up over the city. Then the entire mass of wires, wood, rail cars and bodies caught fire. > > > [Answer] Moved from comment to answer because I've done more research. Try the biblical account of Sodom and Gomorrah, believed to be near the coast of the Dead Sea . The cities were destroyed by means of volcanism (fire and brimstone), and 4000 years later we still don't know where they are for sure. As an argument for the effectiveness of this approach, there is even debate as to whether the cities actually ever existed. The Dead Sea region is (in)famous for its sulfur (brimstone) smell. One of its names over the centuries was "The Stink Sea" because of it. While the region has been tectonically active in the past, there are no active volcanoes in the area in recent times. Igneous rocks are the norm around the dead sea, as are old volcanic craters. To achieve your ends using this example, you are looking for a pyroclastic volcanic event that has a sudden onset, creates pyroclastic projectiles sufficient to smash stone and clay homes to rubble, but does not have an associated lava flow or leave a new crater. It must maintain a temperature high enough to cremate bodies, but not so high as to fire the clay into ceramics, without deoxygenating the atmosphere for sufficient time to allow thorough cremation of the bodies. A short lived lava plume, which originally powered the eruption, sits beneath the two cities, raising their temperature for the duration of the event. This is distinctly different from pompei, where the environment was preserved by ashes and lava flow. **Edit: Summary of some concerns raised in comments** The veracity of the biblical account is not part of this discussion. For that, go to one of the religious (Christianity, Judaism, etc) or archaeology SE sites. This is not an attempt to prove that Sodom and Gomorrah were destroyed by volcanic activity. It is an observation of a recorded event in a real location (Dead Sea valley) that matches the OP's question, and uses the real world geology of the area to establish a plausible natural event that a deity could use in the manner that OP requested. Setting aside the questions that are bigger than this discussion and off topic for worldbuilding, this event comes to mind because: 1. The buildings in the area have been rock and clay for most of history, matching OP's scenario 2. The only eyewitness account of their destruction says they were destroyed by fire and brimstone, matching OP's scenario of destruction by burning 3. The area has been relatively quiescent tectonically for some time, so there was no visually obvious risk factors 4. City is situated above sea level - failed - the Dead Sea is below sea level 5. City is in an semi-arid area - The humidity of the air hardly exceeds 40% and it drops in the summer to an average of 23%. (<https://www.deadsea.com/articles-tips/interesting-facts/the-dead-sea-weather-and-climate/>) 6. The Jordan valley, which includes the Dead Sea area, is a part of the Great Rift Valley that extends from Lebanon into Africa. (<https://en.wikipedia.org/wiki/Great_Rift_Valley>) Tectonic activity is expected to a geologist but not to a casual observer. At present, it is believed that a super-plume of magma is widening the african end of the valley (<https://www.scientificamerican.com/article/a-superplume-is-the-reason-africa-is-splitting-apart/>), so occasional localized magma plumes are a reasonable natural occurrence (especially if receiving an assist from OP's diety) 7. The dead sea area is pockmarked with quiescent volcanic craters, providing plenty of camouflage for the event, provided it is of a sufficiently small scale, matching OP's requirement that clues to the event must be well hidden 8. As was noted in comments, destruction by brimstone (sulfur) would leave a strong sulfur smell. The entire dead sea valley south of Jericho is noted for its sulfur smell. At some points in history it was known officially as the Stink Sea, matching @RonJohn's observation that destruction by brimstone would leave a smell. 9. City was destroyed about 2000 BC - match 10. Destruction left limited clues that have left people guessing - match - some people wonder if the cities existed, others wonder which of several candidate cities whose period names are unknown might be the cities in question. (<http://etzion.org.il/en/parashat-vayera-sodom-and-gomorrah>) 11. Deity intervened to trigger an event to look like a natural disaster - speculative, but matches the eyewitness account, and allows for the precise range of violence that would match OP's requirements . So, 10 passes and 1 fail out of 11 criteria. The event itself must be in a precise range of violence on several fronts to achieve OP's ends. Fortunately he specified that a deity was in control of the event, so this is manageable. It is even semi-plausible without intervention of deity. 1. Temperature in the cities must reach 900 degrees C to guarantee complete incineration of organic remains, but must not exceed 1200 degrees C or there would be glazes and ceramic remains of the buildings. Heat as low as 600 degrees C can do the job given enough time, but 900 degrees guarantees cremation in about an hour. 2. The oxygen levels in the affected area must remain high enough to allow for combustion of organics. There can be no significant ash fall. 3. The buildings must be broken apart to leave no clues. Heat alone will not do this, but bombardment with pyroclastic rocks would do so. Said rocks would blend into the background of the igneous rubble and clays native to the area (from which the buildings were originally constructed). 4. A new crater cannot be formed, since that would leave clues. An event the scale of Mount St. Helens would leave traces all over the continent. Fortunately, there are plenty of old craters in the Dead Sea valley to use for this purpose. **And the crude map that sums up the hypothetical scenario ...** Given this hypothetical map, you could achieve this goal: [](https://i.stack.imgur.com/N7KBW.png) [Answer] Scale it up - you thought "a meteor strike is too visible". Good! If your impact crater is deep enough, people are going to think "valley", not "crater". Hit them with 3-or-more meteors in a row, and dig that crater *deep*. It'll grind that city to dust, and bury it under rocks! Then let the basin flood, and all your evidence is hidden at the bottom of a lake... [Answer] It doesn't necessarily have to be a natural disaster in the traditional sense. It could be that a natural/weaponised biological plague tore through the population making them go completely mad. *They* then tore and burnt the city down. There are several historical references of ancient cities being conquered and razed to the ground by the victors, leaving no stone standing upright (normally over a short period of a few days). Ancient Athens springs to mind. You could have the plague mess with the city inhabitants heads. Making them a huge uncontrollable angry mob and demolish everything in site. The city is torn down/ fires rage/foundations pulled up/ worked stone either geound into sand or even carried off into the countryside. They can then flee the city and either die or recover. Out of fear no one wants to build a city there ever again. Believing themselves to be rational civil people they won't believe they would have done something like that, at least not without reason. Rumours and local propoganda will take hold and no one will know the original catalyst that caused the mob. Over the years many theories have been put forth but none realise that it was actually a biological poison from their enemies/lead lined pipes/local plant life/freak conjunction of a low pressure weather system and volcanics spreading natural toxic gases affecting a previously unknown genetic marker/ even from the toxic metal from a recent meteorite found in a local field and brought into the city for inspection (flame from above) etc. 4000 years later: * the site is destroyed * the site has no one determining characteristic of what caused the damage, making determining the one overall cause impossible to find * the historical record is full of inaccurate conspiracy theories * no evidence of the original biological contaminate survives --- EDIT There are several historical references to ancient cities being lost to legend. The Illiad Troy comes to mind, as well as King Solomon's mines and even Atlantis. Please bear with me :) Even though the city of Troy was rebuilt several times after the famous Illaid sacking, the location of the site was eventually lost. The last city built on that site was around 500AD. It was only in 1870AD that it was 'probably' found. It was only lost for around ~1500 years, much less time than your 4000 year time period, and still it holds many mysteries as to what happened over the years and if it is even the site of the famous Illaid. King Solomon's mines have not been 'found' yet. Although the Great Zimbabwe Ruins are thought by some, to be the origin of that legend. I believe there are more than just Christian Bible sources 'confirming' or mentioning the existence of Great Mines somewhere in Africa. The existence of Atlantis is still hotly debated, with locations ranging from the Atlantic Ocean, Mediterranean Sea, Crete, or even in the Indian Ocean. I think I even once saw a theory about it being in the Pacific Ocean. With no specific location to search, no exhaustive search of the area can be taken to prove/disprove the city existed. As mentioned in my original response, historical documents are not the most accurate resource. What I'm trying to say, is **destroying the city is just the first step if you want the city to be lost to history**. You also need to destroy the historical references to it's location. This will obviously take longer than the initial destruction of the city. Troy is actually a good example. The location of ancient cities are normally referenced in relation to other cities etc not on their actual physical location ie co-ordinates. Inaccurate map making with an inability to correctly determine longitude combined with natural erosional processes can change the landscape over 4000 years. I believe it was described in the Illiad, as being situated on the coast, past certain physical landmarks, with a river on one side. So over time the river shifted courses many times leaving many dried up riverbeds to be eroded to various degrees. The coastline shape also changed. Natural landmarks such as swamps, hills and forests can change with changing climate/erosion and/or man's actions. Newer cities can be created ontop of the old site with different names/cultures and neighbouring cities can fall, new cities can take on old or similar names and create confusion as to historical origin. So, as a further expanded answer to take your edit into account I would suggest you make your Ancient recorded location of your cities be dependent on features that are not permanent, such as the Trojan Example. Then, when the historical descriptive map/records points to certain features, your modern day explorers will be looking in the wrong locations and will not be able to determine once and for all if the Lost City of your Ancients even existed, such as the Atlantis Legend. Even if there are multiple different sources claiming that the city and it's people where real, such as King Solomon's mines. [Answer] The inhabitants of the city developed some building materials which seemed like a good choice back then, but chemistry eventually expletived them up. The rocks and clay of the city were rich in iron oxides, specially red iron, and aluminium. Other composites in the sand, clay and rocks kept this fiery duo from reacting in a [Goldschmidt process](https://en.wikipedia.org/wiki/Thermite). Until one day, an alchemist/architect/healer/whatever came into town, made a concotion that had the catalyst it took to turn the ground and walls into thermite, and accidentally dropped it. The whole desert lit up in an extremely fast chain reaction. The people evaporated and rained as black droplets. Some parts of the city did not become ash, but turned into [lybian desert glass instead. These crystaline leftovers were scattered by the wind throughout multiple countries over the ages, and can still be unearthed to this day.](https://en.wikipedia.org/wiki/Libyan_desert_glass) [Answer] The city is is a city of potters and glazers and they make a lot of money off their bright hard [orange and yellow pottery](https://people.umass.edu/emartz/martzpots/gallery/uranium.htm) and [green glass](https://en.wikipedia.org/wiki/Uranium_glass). So much so that one of the merchants gets greedy and decides to stockpile the raw material for the glaze creating a grand wearhouse to store the gray lumpy rock called pitchblende used in making it, hoping to corner the market. To save space he starks having the rock pummeled into powder and stuffed in sacks before filling the silo. Sure the slaves working with the rock and filling the silo keep getting sick but who cares about slaves. Then one day the a bad storm sets the wooden roof on fire and the building burns collapsing the roof and floors of the warehouse, forming one giant rain soaked mess of powdered pitchblende. Then there is a blinding white flash and the city and its inhabitants are gone leaving a large glassy crater in its place. Depending on the technology 4000 years later they will have no idea the poor mechant just built the world's first nuclear bomb without realizing it. Many early cities were quite small. Sadly this will not work in real life, so it depends on hard you want your science fiction. Although as Someone Else pointed out a radioactive fire could kill everyone in the town, then let erosion do the rest. [Answer] Burn down two cities, right next to each other. When people find the remains of the other city they won't be able to distinguish it from the first. [Answer] Change the locale climate. Just because there's no local volcanic activity (using your original limitations) won't mean you can't still use volcanoes & plate tectonics to effect your city. Throw up new mountain ranges in strategic locations hundreds of miles away to alter the course of rivers away from the city, put the city in rain shadow & change weather patterns. Deprived of water for agriculture & transport the people will leave & the city will die, let the desert creep in & bury it in sand. If burying it isn't enough for you just make sure your activities elsewhere ensure weather patterns that encourage tornadoes & sandstorms in your new desert so over the centuries they'll sandblast the buildings into new sand rather than bury it. > > Or you might go the other way, throw up new mountains elsewhere to block the areas rivers & routes for water to drain off, turn the area into a new lake or inland sea (or at least a swamp). > > > If you toss the right ingredients in the air elsewhere for acid rain (yup, more volcanoes) where the weather patterns will make it fall over it (or trickle in) over centuries the stones will dissolve. > > > You can then let the acidity dilute until fish can live in it, or breach the distant damns with more seismic activity & let it drain, or just leave it acid. > > > [Answer] **High Recycling Value** Ensure that your **rock and clay like substances** from which all buildings are constructed have a **high recycling value** during the first few centuries after the *destruction event*. The event itself becomes less important, but I suggest a massive flood from a busted dam, made of this same material. For example, your substance could be a rich metal ore which requires some moderate amount of work to dig up from the ground. The original inhabitants didn't know or care about metals, and just made buildings out of the raw ore (cut into bricks, or finely ground and mixed with some organic binding substance). Place your city near a mountain pass or other naturally occurring "road". The availability of this building material was key to settling of this city, and supported its growth through the construction of dams to stabilize the water supply. The area is not otherwise rich in resources. Bursting of the largest dam could be part of the destruction event. At the next major regional war, years or decades later, the ruins alongside the road become an easy target for recycling of the valuable material. It's a godsend for the army that takes it: the ore has already been dug up from the ground and cut into neat little blocks, ready to be melted down! All the easily-available valuable material is depleted before the end of the war. That will prevent formation of a new settlement in the area, as the armies move on to their next strategic objectives. Similarly, all smaller artifacts such as cooking pots and utensils, should be made of this same material which begs to be melted down and turned into weapons. Travelers and treasure hunters will continue to extract whatever they find in the area, but will not resettle, due to the lack of a reliable water supply and insufficient materials to build a new dam. The exact location will be forgotten over time but the legends will live on and treasure hunters will continue to search along the road. Evidence from the area's use as a road and army supply route will further obscure the true history of what happened. In much less than 4,000 years, all evidence of what was previously there or what happened, is gone. [Answer] I suggest a terrifyingly strong windstorm, blowing directly across a wide deposit of diatomacious earth and/or fine pumice in front of the city. This will literally erode the entire area into a multi-mile dust plume. Anything weaker than, say, bronze is going to be completely atomized. It might take longer than a day to erode all traces of the city, but I don't think it's unreasonable to say everyone might be dead by the end of the first day. [Answer] So, if sinking into the ocean is not a possibility, this question just got a bit more complicated. Forest fires can reach, in extreme cases, 800° C, but brick doesn't melt until 2200° C. Brick also does not catch fire in an all-oxygen environment. This can generally be extended to rock. However, in the event of a "firestorm", which is due to a natural chimney effect from particularly intense fires, which builds a wind system that feeds the fire until no remaining fuel remains, temperatures can easily exceed that in spite of the fuel source. Their exact causes aren't always understood, but it often involves ideal weather conditions, some fuel source (not always trees), at least 16% oxygen, and the formation of a column of smoke exhaust. After that, winds can reach around 270 kph and nothing remains unburned. These fire tornadoes are about as close to nuclear destruction as nature gets. Depending on how big your city is, if you have a viable fuel source present and the firestorm goes on long enough, this unlikely-but-possible event will destroy it. [Answer] You're a deity, but it sounds like you're not all-powerful. You do like your fire, though. You've got one extra tool in your tool chest over the average deity of your class -- you're under the control of a story author who can make certain arrangements to make this destruction more fun for you and more mysterious for future generations. Have your people build their city on the side of a gentle slope. Nice fertile soil for grapes and olives, trade routes through the mountains, lots of good story reasons why they might do that. Several paths come to mind: (1) **Moderate fire triggers cataclysmic limestone collapse** If they are building with rock and clay, presumably the rest of their tech matches. So no seismological testing was done on the city. Nobody is aware that the nice sloping hill is full of limestone and limestone caves. One day towards the end of harvest season there's a perfectly normal fire, but with all the dry crops around, it spreads -- oil presses, thatched roofs, floor rushes, it all burns. Your normal typical urban disaster... except that the heat and the collapse of structures stresses weak points in the rock and the caverns start to collapse, which in a stroke of immense bad luck triggers a landslide. City pours into caves, hillside pours in afterwards. It will take thousands of years for tech to advance to the point where any forensics can be done, by which time the whole area has settled and overgrown, and the story has long since been dismissed as myth. The book "Natural and Anthropogenic Hazards in Karst Areas" available on Google Books has a few examples of real-world limestone collapses, though none on a city scale. <https://books.google.co.in/books?id=W0j67ucuKR4C&pg=PA17&lpg=PA17&dq=limestone+caves+collapse&source=bl&ots=FbTj1-URrk&sig=v4kx1TnVIgjzBMYNjn5lV-imi1g&hl=en&sa=X&ved=0ahUKEwijiPnzzKfaAhXIvI8KHewnD74Q6AEIwgEwFg#v=onepage&q=limestone%20caves%20collapse&f=false> See also <https://www.uky.edu/KGS/water/general/karst/kgeohazard.html> for more technical discusssion of "karst cover collapse" a/k/a "cover-collapse sinkholes". You'll need some deity-level help to get these natural events up to city size. (2) **Sinkhole of burning natural gas** You want fire, how about the Darvaza gas crater, a sinkhole in an oil field that's been on fire (burning natural gas) since 1971: <https://en.wikipedia.org/wiki/Darvaza_gas_crater> It's only 69 meters wide, and 30 deep, but a few adjustments from your magic powers and you could swallow up a decent-sized town into the flames. It's only in myth that it's grown to a whole city. (The fire burned out after a few hundred years, leaving nothing but ash to identify. Natural processes have since obscured most of that.) (3) **Moderate fire triggers cataclysmic permafrost sinkhole** If you really want the disaster city-size, trigger a sinkhole in melting permafrost, the <https://en.wikipedia.org/wiki/Batagaika_crater> is a km long and growing, big enough to eat a fair chunk of ancient city. Again, slosh around enough rocks and mud and dirt for a few centuries and nobody will be able to untangle quite what happened and how much of the myth is true, beyond being certain that *something* terrible happened here. None of this is as flashy as the pyroclastic flows described in other answers, but I kinda like the idea of a city that has annoyed a deity sinking into a pit of fire ;-) Cover the evidence with a nice "natural" avalanche and the myth will take over from there. [Answer] This is a really cool question. How you destroy it is up to you, but erasing it from history is pretty easy: apathy, or even better, malevolence. Many people have mentioned Pompeii as an example of a perfectly preserved city, but it's not really an accurate parallel. For one, Pompeii was buried only half as long ago as your city. The eruption happened in the 1st Century AD, 2000 years ago as opposed to the 4000 you're planning. And second of all, it's pretty damn lucky Pompeii is so well preserved. I'm not a historian so I don't want to go into too much detail that might misinform you, but in addition to the actual luckiness of the physical conditions, there are several times in history where the city could have been disturbed earlier. Finally it's also incredibly luck there was **interest** in preserving it. You can easily erase or confuse the evidence of a disaster by having humans get rid of it for you. One way this could happen is through colonialism and settler indifference towards archeological remains. Place your city in the "New World" or in other colonized areas. Since many early colonizers and explorers considered the people already living in the places they "settled" in to be inferior or "savages", they didn't really give any thought into the preservation of archeological remains of societies existing there. Take, for example, the North American city of [Cahokia](https://en.wikipedia.org/wiki/Cahokia), which was a Mississippian city larger than London located out the outskirts of modern day St. Louis. The Mississippian culture and civilization was massive, but both historical (i.e. Manifest Destiny) and relatively modern (i.e. the Federal government building a highway through it in the 50's) apathy and aggression erased most of it from history. In modern day we're beginning to actually learn more about native history, but much of it has been lost to time, not simply due to natural wear but also do to deliberate acts (the [Canadian government continued](https://en.wikipedia.org/wiki/Canadian_Indian_residential_school_system) its "assimilation" programs until **1996**). Even the technology around at the time of colonialism would have better preserved much of native cultures. To summarize, if you want to erase evidence of city for 4000 years, have humans keep it that way on purpose. I can see a colonialist power purposefully eradicating historical evidence of a "lost city" in order to suppress protest from native cultures. [Answer] If you were to have a water source (such as a river) near the area it could really help your case, especially since you are above sea level. If a volcano was to erupt you would get your death by fire but leave behind evidence in volcanic rock. If the lava flow redirects the flow of natural water source(s) to the former site of the town erosion should destroy evidence over the years. It would be a double benefit by also ensuring that no primitive man discovers any evidence until scuba gear is invented. By that time all evidence will be downstream. [Answer] My first thought is to submerge it. If you look at the ruins of the Titanic, as an example, which sunk only a century ago, you'll find that it's on the verge of complete decay. Within a couple of decades, it will be completely gone. This is mildly different from a massive flood, as floods drain with time. Additionally, in spite of the fables of Atlantis/Lemuria/Mu, [continents can't just sink](http://www.badarchaeology.com/lost-civilisations/lost-continents/the-problem-with-sunken-continents/), at least not without an equal and opposite reaction. For this, there would have to be some kind of massive seismic event which would permanently change the terrain. After that, just let the salt water do its thing, and a few centuries later no trace would be left. Additionally, you might consider looking up the [archaeological history of Ur](https://en.wikipedia.org/wiki/Ur), which I believe to be the oldest city we know of (3800 BC). It might give you a notion of how ancient cities are found. [Answer] Alright, we have established that you're a supernatural being, probably a god or a demon. We have established that you want to destroy the city within 24 hours. We have also established that you don't want to have any clues that allows humanity from 4000 years later to identify. I shall assume that you want the city to be completely wiped out from the face of the Earth within 24 hours and nobody will come across it in the future to notice that there was a city on that site. So you have several options: 1. Explosions - Many explosive compounds in our modern world can be used to reduce a city to nothing but rubble. Proper positioning of the explosives can completely demolish a city. You'll need plenty of small-sized explosives, depending on the yield, but you can't go crazy and go with large bombs. If the explosives are too big, the effects will be visible 4000 years later. If you do it right, your city of clay and rocks will be dust. Wash it down with heavy rain for several hours right after you're done, and nobody will ever know there was ever a city there. It's not that it can't be traced, it's just that there will be no trace 4000 years later. 2. Firebombs - A combination of city-wide firebombing accompanied by heavy rain and winds for several times within 24 hours will turn your city into nothing but quicklime. We humans can't do this, but you're a supernatural being, so it's not outside the realm of possibility. What you do is basically bomb the city first, then drop the firebombs, then while the city is still hot, pour in the rain. The temperature needs to be sufficient and the rain needs to be significant, though. You can combine this technique with number 1. 3. Flood - If the city is build by the side of a mountain, a continuous heavy rain can easily wash away the majority of the city. What you have left is the site of a city, but it's not really untraceable. The city is gone, but the bricks, the furniture and the roads will still be there, only buried in mud. This is the least reliable method. If you are a supernatural being with enormous power, such as a god, you can use the above methods together, from 1 to 2 to 3 instead of picking one. You need the explosives to destroy the city, you need the fire to turn the bricks and stones into dust and you need the rain to wash it all away. [Answer] Have it literally swallowed by the ground. Edges of tectonic plates sometimes fold underneath each other. Usually it happens on non human timescale. Make it happen overnight. Remains are buried so deep they can't be dug up. People can take a guess at what happen and the city will be a myth. [Answer] Extending Dan's excellent answer: We have a two-stage disaster. First, there is a Tunguska event except the rock was part of a binary pair. The main effect will be blown down trees--but even if there are trees around to be blown down (how many would there be in such a situation? Trees = firewood!) they would be harvested by those nearby. The blast wave will start a bunch of fires, in 2000 BC there will not be effective firefighting and such cities were very flammable. (You can't make a clay roof, they would be wood & thatch.) A firestorm could easily result--and a firestorm normally burns everything in the area. The second rock is much more solid--it survives to impact--and plows into a lake upstream of the city. It's energy is mostly expended on throwing the water out of the lake--and a wall of water comes tearing through the remains of the city. Archeology can figure out there was an impact event somewhere in the vicinity but can't pinpoint it. Some bits of pottery and the like will be found--but there would have been people upstream also, this won't pinpoint the city. [Answer] I don't really know how you would get hydrochloric acid from a natural phenomenon. But, if you are a god, you get it from somewhere and put it in a cloud floating above your offending town. Assuming its buildings are made of rocks, they would melt if enough acid rains upon them. People would probably die from fumes in the first few minutes of your heavy acid rain. Oxides and salts in the rocks would react to the strong acid. Once you had enough of it, throw some lightning bolts on the ground. [Answer] 1. Have an undersea dormant volcano with a peak just above water, making it a desertic rocky island with steep terrain and few resources other than the seas. 2. Make some people build a village there, living as fishermen and maybe as sea merchants or pirates. They uses the abundant local rocks as a resource for its construction. 3. Make the volcano explode and erupt violently. 4. Have lava flow over the village, burning everything that could burn, killing everyone and burying everything with layers of ashes and igneous rock. 5. The volcano causes some earthquakes and tsunamis that fracture its peak (i.e. the island), making the island sink under the ocean, in pieces. 6. The pieces of the former island that were closer to the coastline ends resting deeper in the ocean than those that were more closer than the center of the island. Since the villagers were fishermen, this means that the burned rubble of their houses and the fragments of their bones will land in deep ocean floor, covered by a lot of rocks from of the island interior, by newly formed rocks from lava eruptions and also from sand carried out by sea waters. 4000 years later: * Oceanographs and geologists might evetually figure out that there is a volcanic sunken island. Getting details though would be very expensive, so its unlikely that they'll study further. * Getting some evidence from the disaster is somewhat hard and expensive, as getting evidence from seafloor is costly. Further, seafloor is covered by a lot of corals, sand and rocks. * The island was rocky, so there is no surprise that there is a lot of rocks scattered in ocean floor everywhere around the underwater volcano. * They might even find in deep ocean floor, vestiges of the burned scarce vegetation that once existed in the island and maybe bone fragments of a few animals... If those are lucky enough to survive for 4000 years in the ocean floor and in the cone of an unstable volcano quakeing, tsunaming and landsliding several layers of lava and rock over it. * It is extremely unlikely that they will ever discover vestiges of human presence there. [Answer] So no flood, no volcanism, no earthquakes. Without some natural disaster, you need combustible material and/or arid climate for a fire to rage. If it's a huge forest in a very arid area, you could have a massive forest fire that burned long enough (old growth trees maybe? or a sudden aridity that dries up a lush forest) to incinerate all organics. The rock and clay infrastructure could then be buried under layers of topsoil, with 4000 years of forest growth hiding the evidence. [Answer] 4,000 years is a long time, you don't necessarily have to destroy the whole city at once. Nature in general does an excellent job digesting remains once people aren't there repairing things all the time. For example maybe winds combined with sand, frequent flooding or basically any form of erosion could effectively level the city to leave the precise amount of clues you want to leave behind. It could even be that the area used to be a different climate entirely or shifted through a climate that caused it. Especially for a supernatural being who is presumably immortal, letting nature take its course to digest the remains would seem like an appealing option. [Answer] What if a bomb blew up a sand dune and created (or just happened to appear) a tornado so powerful that, with all the sand in the air from the blown up dune, it eroded the clay and rock buildings, along with every lifeform that was on the surface? It's silly and probably impossible but kind of a good idea when you think so. [Answer] The question and details do not mention this, but there are many assumptions that the construction materials of the city are rock and clay. The original stories in Genesis Chapters 14, 18, and 19 do not seem to allude to their construction either. What if the city dwellings were thatch or sticks? Then you face a situation where the fuel from the fire creates its own weather, like with a forest fire. Examples that come to mind are the Tokyo bombing, Fire of London, or the Peshtigo Fire. In the last example there was nothing recognizable when the farmers returned to their farms. [Answer] How about a freak storm that rains accelerant or some form of hydrocarbon? Then a lightning bolt ignites it. Kaboom! I realize this streches suspension of disbelief, but there are moons in our solar system that have hydrocarbon rains. Chalk it up to some tornado coming across oil seeping out of the ground and picking it up. There's certainly crude oil that is light enough that this might be feasible. [Answer] Everyone else seems to be focusing on burying the city, but perhaps the best idea would be to blow it sky high! What you want is a geological event similar to Mount Saint Helens on May 18, 1980. The blast removed 1300 feet from the peak of the mountain, flattened trees for miles, and flung earth-moving equipment around like scraps of paper, among other things. Any city located at that location would be scattered in tiny pieces of the countryside. Even a few years of normal weather after that would completely destroy anything remaining - not that there would be enough to piece together the city in the first place. [Answer] A: Bury the city in a sandstorm. This fits with your semi-arid scenario. If you have it happen at a time of greater dryness, then in the wetter modern time, grass has stabilized the sand. B: Major ash fall. Mt. St Helens dropped feet of ash nearby. And St. Helens was small. Just concentrate the ash on the city with your deity-ness. C: Caldera explosion -- Yellowstone does quite a number when it goes off, making whole states uninhabitable. D: Break an ice dam. The Clark Fork river was dammed by a tongue of ice in what is now the Cabinet Gorge in Montana. When it let go, 15,000 cubic miles of water drained out in a few days. At Palouse Falls, the stream was 20 miles wide, 700 feet deep, moving at 70 miles per hour and moving boulders the size of houses. E: Solar flare on a clear day. At one point this was hypothesized as the cause of the Libyan Glass a section of desert with a fused surface. Flares tend to be overkill: You're quite likely to glaze half the planet, and cause no end of other mischief boiling the surface of oceans. F: Less natural: Convert all of the potassium in the rock to K40. This is makes the place both thermally too hot, and radioactively too hot to survive. Pick something that would give a dose of radiation that would be lethal in a few minutes. A true "Curse of the City of the Dead" As a side effect food left there wouldn't rot, nor would there be rats, flies, and other scavengers. G: Unstable mud. The city is built on one of those clays that turns to liquid with the right shock. The entire foundation of the city flows away into a canyon. H: Poisoned water. Connect a here-to-fore unconnected aquifer to their water supply. Say one that runs 20 ppm arsenic. This is another City of the Dead. City is there, but visitors don't last long. I: The lake nearby collects CO2 and H2S and SO2 from deeply submerged volcanic. fissures. The gas disolves under pressure. An upwelling causes some gas to come out of solution, lowering the density of the water column. This spreads rapidly. This actually happened in south America, and the river of CO2 killed a village. This leaves the city intact. A sufficiently active fissure keeps the valley full of unbreathable air. [Answer] No real, physical event is required. You could make the city completely mythical, a pure legend - the city never existed in the first place. A story grew over time, culminating in a full fledged legend that sounds true but isn't. You could have a few random volcanic clues or rubble that seems tantalizingly close to the story but are purely red hearings. ]

[Question] [ In my fantasy world there exists an order of monks known as the Noncara/Non Cara (haven't decided which form looks better). The Non Cara practice a theology based solely on works. By this I mean: they believe in works/deeds alone. How this manifests is the Monks renounce their former selves, livelihoods, and even renounce their own names. The Monks now freed from the constrictions of notoriety are able to do their holy work without recognition. Since they believe recognition and fame distract and even diminish one's deeds (since they'd be done for fame instead of "God" so to speak). However, I've run into a slight issue. While designing their outfit was easy: simple black robes with the only identifying feature being a "dreaming eye" on the hood and their armor would be likewise simple and painted black with their helmets being simple with only a dreaming eye being identifiable. The issue I've run into is how would they communicate if they don't and can't take names? How could they in conversations distinguish between one another? Note: This is mainly about speech. [Answer] ### They don't actually need names. Names aren't used that often in everyday communication. Body language is very effective for indicating which person in a group you're talking to. And to get somebody's attention, simply call out "brother!" in their direction, and look at the person you're referring to. The only other situations where you use names are when you're referring to somebody in a 3rd-person situation: * Did you see what Bob's wearing? * Remember when we hung out at Sarah's place last month? * Have you seen Bill around here recently? But the thing with these situations is that they're all referring to that person's individual identity, which is what the order of monks is trying to remove. These conversations wouldn't be possible at all, but that's the point. You never talk about somebody behind their back, or express admiration, because all members of the brotherhood are equivalent: nobody's the leader, nobody's more or less intelligent, stronger or weaker than anybody. You never ask where your buddy is, because any member of the order will suffice for whatever you need right now. Nobody has any expertise, any reason to be more needed than anybody else: they're all interchangeable. This will cause some problems: * There's no leadership, so the order can't grow to a very large size without organizational problems. * There's no system of allocating talent to needs: the really good carpenter is equally likely to be asked to work on repairing a chair or picking fruit. This means that some skills are wasted. * There's no system of social rewards: people who do good deeds don't get recognized, people who behave badly are not reprimanded. But all of these problems are derived from the lack of individual identity, not the lack of names. [Answer] If your group renounces their personal identity in favor of their work, the obvious thing to call them by is profession. If a particular brother is responsible for the monastery gardens, he's Brother Gardner. If he's responsible for their walls, he's Brother Mason. If he's responsible for their horseshoes and swords, he's Brother Smith. You'll note that these are all actual last names, because this system was for a long time quite a popular way to create nicknames if you needed to distinguish between, say, two Joneses. In a way, you've simply recreated such a society, only *everyone* has the same "name". Now, this does leave the question of what to do with apprentices, those who haven't yet demonstrated that they should be allowed into a trade. In day-to-day conversation, they don't *need* to be called anything, but it's useful for their elders to have some way to tell which of the young whippersnappers they're discussing. You could have them sponsored by an older member, whose name/title they take until they get one of "their own": Brother Smith and his novice, Brother Smith's Apprentice. Or, they could have some kind of title based on something more arbitrary: what room they sleep in, what day they came to the monastery, some kind of defining physical characteristic. [Answer] # Precise Pseudo-Pronouns In addition to developing a system along the lines of [Cadence's answer](https://worldbuilding.stackexchange.com/a/149479/59676), they seem to be a good candidate for developing a pseudo-pronoun system based on deeds or locations known to the residents of the monastery. E.g. Resident of the Second Kitchen-Adjacent Cell, One Who Fell Into the Well Once, Late Night Copier etc. These are 'pronouns' in the sense that they are used in place of (instead of) names, but not really pronouns in that they aren't standardised like normal pronouns in common languages are. The fact that fame is considered bad, and that the monks do not want those pseudo-pronouns to turn into de facto names will mean that there will be some social pressure to not use the same reference too many times, and instead people will try to mix up different ways to refer to someone. Perhaps more recent deeds will be given preference because they're easier to remember. Also keep in mind that such a system would rely heavily on the community knowing each other's daily activities, which would likely pair well with a more collectivist approach to life - something that'd be right at home in a monastery. [Answer] **This makes the Order very personal** Renouncing one's name for the sake of monkhood means giving up all the things that are personal: including privacy. If embraced, it would create an incredibly strong and trusting bond between the brothers. * If you need to speak with someone, you must walk toward them such that they can see you speaking directly to them, alleviating all need for personal nouns in the conversation. * If you need to inform someone (person B) of another's (person C) disposition, you would be forced to bring person B to person C's presence for the sake of that conversation. E.G., "there is one among us who has fallen ill and cannot continue with his duties, may I take you to him?" This would certainly slow down communication as physical travel time is now required to avoid personal identification. But, like I said, it would create an intense brotherhood and demand substantial trust, honesty, etc. (E.G., "I observed one who has violated rule 23.3(d) of our Order, may I take you to him?" of course, you'd better be right about that infraction of 23.3(d).) **The problem is with war, but for that purpose you might require titles** Planning a battle could be done as previously described. It would be slow, but it would of necessity be thorough. However, there is need for long-distance communication *during* battle. And that's a problem. * One option is that your no-personal-noun Monks have no involvement in combat. * The other option is that personal pronouns (titles) come into use in combat. But I personally think this stinks because it basically breaks your rule that there's no personal pronouns. If permitted, they would quickly become the defacto "name" for that person (such is the case in some Convent orders where Nuns adopt a name, e.g., "Mary Margaret"). But now we have a personal name. If you're serious about the personal name rule, I can't see how you can permit the monks to be involved in combat other than singly, farmed out to (e.g.) governments/armies as-needed, like you might a wizard. In this case they would always be referred to as "brother" an no personally-identifying pronoun would ever be used or needed. The moment you allow two of them together will require personal pronouns ("hey! Brother-who-took-an-arrow-in-the-arm-last-week!") But! Have hope! Because I can think of one way around this: random names that change every time the brotherhood is assembled to battle. There is a Holy Urn filled with slips of paper, each having the name of a Saint, or mythic hero, or some random word. With each assembly, the Brethren draw names and use them only for the time the assembly was called. Once the Assembled Brethren are dismissed, the names are no longer used. Thus, no one has a *permanent* personal noun and the habit is to not use them other than when necessary. And as I think about it, with each "name" can come a diadem or some other marker worn by the brother-who-drew-that-name such that people are recognizing the diadem, not the brother, by name. **Where will you have problems?** With the local townsfolk, or anyone else not of the Order who must conduct business with the Order. People would quickly figure out the very personal way of speaking to people (eye-to-eye, direct to your face), but that nagging habit of calling Frank by his name just won't go away! Why did he have to join the Order Frank (I mean, "brother")? Why? Anyway, relationships with people outside the Order will always cause friction, especially if that blonde-brother-with-the-bedroom-eyes-and-roving-hands happens to touch your daughter again. * Ideally, the Order is self-sufficient and has no need to interact with the outside world other than in emergencies. * If not, CDE, you're hosed, because the outside world will eventually demand individual recognition — probably when the first crime occurs, but certainly when the first batch of taxes are owed, IMO. [Answer] > > The issue I've run into is how would they communicate if they don't and can't take names? How could they in conversations distinguish between one another? > > > * **serial number**: extremely depersonificating, it is what the nazi did with the prisoners in the concentration camps. * **nick name**: changing name to renounce to your former self is already what every real monastic order imposes on its members, and for your specific question it can be made a constant recall for humility if slightly derogatory or humiliating, i.e. brother Baldy, or brother Smelly Mouth. * **wearing a label**: something as simple as a piece of cloth with a symbol on it, maybe even changed every day. Today one will be brother star, tomorrow brother bird, the day after tomorrow brother circle. Not exactly the best method if you want to keep some accountability, though. [Answer] Doesn't referring to a specific individual (somewhat) defeat the purpose of the order? Addressing people by profession means they are being *recognised* for something. The question we need to ask is, **at what times is it *hardest* to achieve something without names?** So here are my answers and potential solutions. Note that in some cases, things are going to end up being less efficient, but the monks believe it's a worthwhile trade-off. **1. Getting someone's attention.** Let's say in a room with several monks, Brother A sees Brother B with a toolbox and wants to ask whether he has a chisel. Or, Brother B seems to be carrying something to the wrong place. Brother A would refer to Brother B by his location or activity (e.g. Brother with the toolbox, etc.) The reference is based on the immediate situation, rather than the person's identity. **2. Expertise.** Bob can speak Latin. Bob can carve wood expertly. Bob remembers which of the hundred shelves a particular scroll is on. Well, too bad. The monks gather several times a day for several reasons, one being that someone can ask the whole congregation for someone with such skills/experience/knowledge. **3. Division of responsibility. Scheduling.** Building a chapel requires someone to come up with a plan, someone to co-ordinate the work, and many to perform parts of the labour. Too many cooks spoil the broth and so forth. Similarly, if something must be done in shifts (watching the flame, ringing bells) then some system is needed for scheduling who is where at what time. In this case, at meetings people are asked to volunteer for jobs/roles, and they raise their hands to claim the task, and then know it is their duty to show up and perform it. Nobody else need know who they are. Alternatively, they can place black marks on a roster or responsibility chart and, in cases where needed, be present at a meeting place at particular times so that others can co-ordinate with them without knowing who they are. **4. Training.** This one is not so much a question of names but more an ongoing teacher-student relationship which implies recognising someone and gaining respect for them. While it may be seen as a "necessary evil", an alternative is to intentionally rotate teachers and students, and encourage a "seeker/scholar" approach to learning whereby a student pursues knowledge and skills so it really doesn't matter if they consult a different person each day; indeed perhaps it is quite beneficial. In addition, there can be an emphasis on "teachers" writing down their knowledge anonymously and "students" reading it. **5. Referring to third parties.** Brother X is missing! Is he ill? We need someone to fill his place! Well, that's what the frequent meetings are for. If Brother X is ill, he can let someone know what his task was and that person will announce it without having to name Brother X. Or let's say Brother Y doesn't realise he's good/bad at something. Can you warn others? No. You just have to tell him, and it's his responsibility to act accordingly. That's how the order works. Brother A knows that B possesses an item that brother C needs. But A cannot identify B to C. A can simply tell C that *someone* has the item and during one of the meetings it can be requested. There are no secrets in the order; after all, they would be a selfish thing. [Answer] Job title-based names as suggested in other answers are a good functional work around but would ultimately go against the anti-notoriety philosophy of the monks. Once you start to regularly distinguish between the 'late night copier' and 'the late afternoon copier' it won't take long for people to work out that one is more efficient than the other (or uses up more/less candles). A system of temporary names would be more egalitarian. In most individual interactions you don't need to specify a name as it is obvious who you are speaking to. However, where a small group of monks had to participate in a group activity such as cooking a meal or engaging in warfare they could assign names for the duration of the job. As long as these names only existed for the length of the activity it would be difficult for an individual monk to gain a reputation that applied beyond those who had directly worked with them and recognised them. Rapid rotation of monks between jobs would also help. If the same monks always cook and other monks always fight they will gain an appreciation of each others qualities regardless of even a rigorous prohibition on names. [Answer] You mentioned them wearing armor. This means they will fight in some capacity. Since you require them to communicate with each other, that means they are not solitary wanderers. This means, sooner or later, they will fight in group battles. You may want to start solving the naming problem from this angle. **For effective combat, they need clear and constant identifiers and solid hierarchy.** You don't want to accidentally messing it up and sending your weakest monk to reinforce the gates. Otherwise, they WILL be streamlined with any slightly organized and tactical army. The other answers are spot on. Use a symbol and a number. I just checked up on Star Wars clone trooper "names". Your monks can take their best weapons or roles and add numbers to it. Sword 22, Spear 12, Bow 42, Smith 2, Cook 7... For the apprentices use colors or simple things. Ash 12, Pebble 7, Idiot 143, ... You may want to add something extra but short, like letters, in case monks from different monasteries gather at one place, and they use the same system. --- It came up in other answers, so I'll expand my answer in line with this. The monks have to be able to recognize skill and experience in each other. If they don't, they will be incredible dangerous to themselves. They would waste resources, work slowly and ineffectively. Think an idiot, inexperienced forager gathering poisonous mushrooms, bad smith doing sloppy work at their armor and weapons, etc. You have to have trade-offs and alternative solutions. History, especially religion already given us one such option: Many mix up notoriety and recognition with identifiers. Actually, Christianity solved this problem already. **One of the seven sins is Pride!** That's taking pleasure in one owns notoriety and recognition. Those living in accordance to the religious teaching don't accept any kind of recognition as their own work, both inwardly (in their mind) and outwardly (in speech) they attribute their own skills to their god's guidance, forbearance, ... Their skill level still linked to their identifiers and that accumulate recognition (it must, so they can function properly), but its always passed on, directed toward their god. Refused in every opportunity to be attributed to them personally. [Answer] They just point and say "you!" when referring to each other. If a monk is not present, they refer to the individual by the deed, like "the forger of this blade", since their faith holds deeds and works as important. Conversation about someone which is not deed-related would be avoided. They'd not speculate on what a monk likes, or thinks, only does, so there should always be a deed they can refer to. They would avoid the use of such identifiers as a permanent identifier for a particular individual, so although the monk-who-farted-during-morning-prayers would be gossip for the day, they'd not use that phrase to identify the same guy when he injures himself; it'd be "the-monk-who-cut-himself is over by the cornfield". The monks would work hard on not associating fixed labels on each other. [Answer] I've seen this get touched in other answers, but to specify: **Titles belong to an office, not a person.** Abbot is a title, and if a name isn't attached, any notoriety goes to the office, not the office holder (although many will attribute things to the current holder.) Abbot Bob gives credit to Bob, the Abbot of the Order gives credit to the office and the order. The same goes for combat. You will have the Marshall, Generals of specific arms, Captains, Lieutenants, etc. So the Marshall can give an order to the General of Foot, who sends the order to the Sargent of the Red Banner, who passes it along to his soldiers. Again, praise would go to the Red Banner, not any soldier within. This already happens with military units... By only using titles, even if one monk acted above and beyond, the best you could say is that a soldier of the Red Banner acted bravely. Additionally, with proper training, soldiers don't have to be micromanaged. The general plans with Captains who briefs his Lieutenants who expect his Ensigns to act independently to plan with squads small enough that eye contact and weapon IDs are all you need. The Ensign orders his machine gunner to provide cover. Offices and ranks change hands. You can even enforce a rotation policy... A valorious Soldier of the Red Banner might rotate to the gardens, and this is well known, so people don't bother trying to ID somebody even by position. Using direct communication, jobs, and titles when hierarchy is necessary would allow you to avoid names whilst also ensuring that external praise goes to the order or the office or department, as it becomes frustrating to get more accurate... Your frustration *actually proves that it is working.* [Answer] Let's consider the goal before going too deep into the question itself. These monks are trying to eliminate personal reputations, while also creating an orderly and militarized society. Many suggested solutions that involve taking away names actually do more to put the individual in the spotlight. For example, if someone has to call a gathering to ask for a carpenter, then every carpenter will have to reveal their skillset to the group. This becomes even less anonymous than a name on a work order somewhere because then total strangers will be able to see you in passing and know who and what you are without even needing a name. Titles such as "brother master carpenter" also have invese effects on containing reputation, because you are again identifying a person by their works and talents. Every time someone sees that person they are reminded of that person's talents. For this reason, the goal instead should be to separate the person's work life from the community. When you go to work, you work in silence and obscure your appearance as much as possible such as you would with a Burqa. At work, you have no name, and to work with your identity revealed is considered obscene. Work places would be built around privacy. If you are to design a bridge, then several engineers would draft their plans in private rooms and put them into a drop box one at a time so they do not see each other's work. If you are farmers, then you would work a different field each day so that the quality of a crop in one place does not reflect on the farmer that works that land. In cases where more organization is needed, a number, color, or token is assigned to a person just for that job. That way the soldier with the green 32 knows his exact rank-and-file during a military campaign, but when the battle is done, he is no longer green 32, and if he goes back to war again, he does so as red 13. That way, even if people start talking about how Green 32 killed 20 barbarians, it's just going to be a different guy next month anyway; so, everyone who tells the story understands what they are really saying is "someone killed 20 barbarians". By obscuring who you are when you do things of note, there is then no need to take away a person's name. Your name could still be John, all your friends could call your John, but at work you are just one of many unnamed persons. While your Burqa is on, you could be a general in the army or coal miner, but when you go home, you are just John and no one else needs to know the difference. [Answer] It occurs to me that this question already has a very precise real world answer. Monk orders have existed for millennia with true vows of silence. Clearly they do organise matters, and can communicate to about others in the order. Equally, as they are silent, they don't do this by using, or referring to, personal names or identifiers. Indeed, they do it without being able to reference *far more matters* by labels and words. Conclusion - its not difficult. But you'd have to research them to find details *how*. In effect this is an a proof that its done, workable, and usable, in our real world, rather than exactly *how* it's done in different communities over time. [Answer] As a reader I can never keep names straight, and I fall back on the character's intention and motivation and history. Maybe instead of where they work, Gardener, their new name would be about what they are trying to accomplish in their work and as a monk. Why are they the gardner, because it was easy? Not good enough to be a monk. Because it got them outside? nope. Because they don't like people? Wrong order of monks. Because they like flowers or beauty? Maybe, but too generic. Because they believe others feel peace when nature is well ordered in a beautiful garden? That might work. The monks true calling is giving peace of mind, through gardening. Call him Greenpeace (overused), or Makepeace, Gardenpeace or some variation on the latin that works in english. Google translates "garden peace" as "hortus pace." "Garden serenity" as "hortus serenitatem". It would come later in the apprenticeship, at some critical rite of passage. Their apprentice name could be the worst thing they did, or what the negative impact of their former life was, maybe with a place name too. What is the negative impact of thieving, murder, soldiering, or medical school? Thus the name change is the transition between the two types of impact. [Answer] **They get a new ID periodically.** Some sort of color code or number which is assigned randomly to each monk every day or week. The ID could be permanently attached to the robes and they just pick up their robes randomly each week from the laundry. Tasks would be assigned to the ID instead of individuals. The only problem are unique tasks or professions. If you have only one gardener monk or one sculpturer monk you can’t assign their tasks to a random ID. You have to assign to the individual with the specific knowledge which would allow that individual to earn fame as Gardener or Sculpturer. [Answer] ### Notoriety There are two kinds of notoriety: * Fleeting: who will remember Justin Bieber 10 years hence? * "Eternal": Cleopatra, Leonardo da Vinci, ... Any kind of temporary designation allows the fleeting kind of notoriety: "Brother Cage1 created a most wonderful sculpture of X". ### Recycled Names. An absence of designation is a hindrance for management (planning); thus I will assume temporary designations are necessary, and therefore there may be fleeting notoriety... it's unavoidable, really, as fleeting notoriety is synonym with recognition of competence which is necessary for effective management. I propose that the order simply has a pool of names. Every time a new monk is ordained, they forego their name and pick up a random name from the pool. Whether this name is attached to them for their lifetime, or if a monk changes name on the day they celebrate their ordainment every year (for example) is up to you. No record should ever be kept of which monk picked up which name. I would advise against changing every day, or changing all monks at once, as it would make it very difficult to plan ahead or to remember who is who. The names can be as personal or impersonal as you wish it; the most important aspect is that they are recycled. There is no single "Brother Willow"; indeed, if you change name every year, there were hundreds of individuals referred to as "Brother Willow" in the past centuries. And the sculptor of X may have been "Brother Willow", but is also the sculptor of Y, 2 years later, known as "Brother Oak". 1 *In Red Sister (& co) from Mark Lawrence, each sister takes on a new "name" when graduating from Novice to Sister. Sister Cage is the main character and narrator. Other names are: Abbess Glass, Sister Apple, ...* [Answer] Rather than connecting an individual to a timeindifferent identifier, i.e. a name or a title, you can connect them with their current **state**. This has the benefit that you dont focus on the individual, and rather focus on his tasks. It allows the members of the order to be truly interchangable. Examples are: * The gardening monk * The sitting monk * The ill monk * The leading monk (who will only be the 'Leader' as long as he's leading, if someone eles takes the lead he will automatically take the lead) * The monk monk cleaning the dining room (if there are multiple monks cleaning) Note, the degree of specification of the state is dependent on the number of monks in a similar state. Also note, how this is differerent from calling someone the Gardener or Smith, as with such identifiers, you provide a constant mean of identifying someone, so you might as well stick to names. The only challenge with this is, that you can not use the states to convey a charachter to the reader. You can circumvent this by either referring to a specific monk by their appearance (the monk with the bend back), of connecting a event with them (only for the reader) i.e. > > The monk who had joined the order on the first day of summer in the 567 year is the monk pealing the potatoes > > > Then subsequnently you refer to the him as the monk peeling the potatoes in interactions between the monks. Finally, if it seems to complicated to differentiate between several monks, differentiating between them probably is not relevant. [Answer] Based on other ways I've seen this work in novels: 1) They can choose token identifiers. If you wish to preserve their lack of identity, have them choose a new identifier every day. Maybe something like animal pins they can wear to make their new identity clear. This is derived from the Unsullied in the Song of Ice and Fire universe. 2) Identify them by job title. This will maintain a lack of identifiability and even imply some fungibility as any janitor can answer a call for "Janitor". This is lifted from Chuck Pahlankiuk's "Survivor", wherein the first male child in a family is always named "Adam", all subsequent male children are named "Tender" (as in they tend to things), and all female children are named "Biddy" (as in they do others' bidding). [Answer] They could have relative identifiers from meal place seatings. "My left hand man", "my third-right-hand man" etc. [Answer] Depersonalize the order. As part of their creed, they abandon all ego and go on to live without an identity. There is a metal band that does this. They are called Ghost and, asides their vocalist, every member of the band is called "a nameless ghoul". To distinguish a nameless ghoul from another nameless ghoul, they assign an element to each one. [Their interviews are quite funny.](https://www.ukmusicreviews.co.uk/interviews/interview-nameless-ghoul/) > > **Good afternoon Nameless Ghoul, how are you today?** > > > I am very well Kevin thank you for asking. > > > **Let me just thank you for taking the time out to speak to me.** > > > No worries, thank you for being interested in us and what we are about. > > > **There are five Nameless Ghouls in Ghost, all of you being instrumentalists. You all take your names from the elements and so may I ask which element are you?** > > > Yes you may Kevin and I am Fire. > > > Since you probably want to have too many cultists, you can probably assign each one the name of a monster, and make the assignment temporary. Someone may be brother imp until his team has finished their mission and disbanded, and then take the name of brother kobold on the next round. Also take a page from the Game of Thrones's unsullied army, who take names such as "gray worm", "white rat" etc. [Answer] They could communicate like Members of Parliament. Instead of "I address my question to the Honourable Member from Bollocks-Biggleswaithe" they could say "I address my question to the Humble Brother from Bollocks-Biggleswaithe". ]

[Question] [ My world has a school dedicated to the teaching of magic. Nearly all parents who can send their children to the school do so. The school, as part of their teaching method, exposes their students to life threatening circumstances. They do try to intervene before it's too late, but every year several students die. Yet there are no complaints or protests about this from parents, they simply accept the loss and none of them try to pull their kids out of the school because of the danger. What circumstances would produce a society where parents were so accepting these circumstances and willing to put their children in danger like this? These people are human. [Answer] # Cost-Benefit Every year people die crossing roads, every year people die kayaking in the alps, every year people die playing bowls (possibly not related to the activity), every year people die driving a car. To have magic available is a great benefit, against what cost? If 1 student dies out of a school of 2000 every year, that's not a great risk. If 10% of the intake survives, perhaps it's not worth it. --- If you want to increase the benefit, you can increase the risk of not going. The children are perhaps accepted because they already have access to magic, and it's inherently dangerous to be untrained. A few students die every year, yes, but that's a lot fewer than would die if the school wasn't available. [Answer] **Any society that recognizes that nature is a brutal teacher, and is willing to live with losing some of their young in order to ensure that those who are able to harness such powers correctly are the ones who live on to use those powers and to procreate.** Even without the presence of magic, do consider the huge majority of species on Earth. Offspring try different behaviors, and stick with what works. Many behaviors are instinctual, honed by thousands of generations of natural selection, but some behaviors are learned from experience. Typically, the "more intelligent" the species is, the less of its behaviors are governed primarily by instinct. Every now and then, and usually to the tune of a significant fraction of a litter, young individuals try things that *very definitely do not work* and end up paying the ultimate price for that. **The individuals that survive all the way to reproductive age are those who correctly interpret and judge their environment.** Generally, the others perish, and typically do so long before reaching reproductive age. Many die very young, as little more than infants. Not only does it happen, but it happens for both carnivores and herbivores; just because you eat meat rather than plants doesn't mean you are immune to this! Quite to the contrary, in fact. I can imagine that a society might develop that way if they have a long history of living in tune with nature, meaning either their environment or their own beings, as one might expect from a species able to harness magic. Death is something not feared; it might perhaps even be embraced as a chance to **weed out those individuals who are not sufficiently able to interpret their surroundings and their own power, *without* causing significant collateral damage.** (The school, in this case, can provide an environment where the risk *to others* is reduced compared to the society at large. The primary purpose of the school might then even be to offer that environment, not to offer teachings as such; students are expected to experiment with their abilities, and if they are unable to handle their own powers, well, too bad for them, but at least no one else got hurt.) If those abilities would manifest themselves anyway, it may be preferable to learn how to control them in a safe(r) environment first. *The species or culture is aware of the process of natural selection at least to some extent, but instead of fearing it on the individual level, they embrace it as a society.* The last has a very significant consequence: **Their society is less concerned about specific individuals, and more concerned about the individuals' lineage or even society as a whole.** This will have far-ranging consequences throughout their society, much too so to fully explore in a few paragraphs. For example, two things you will probably *not* see in such a society is a great deal of effort being put into health care or rehabilitation of criminals. (As an example towards the latter, someone convicted of a crime may be branded as such and effectively become an outlaw; they are allowed to live on and get a second chance, but the punishment for a *second* crime may be extremely severe and possibly open for all to administer, right up to something like capital punishment for shoplifting.) Individuals may still grieve the loss of someone who was close to them (mate, child, parent, etc.), but for the most part, the onus from the greater society will be on accepting that not everyone can survive, moving on and taking care of those who do. [Answer] **A Caste Society** If your society is based on some kind of caste system where the magic users are on top of the hierarchy, risking the child's life can be the way to a better life. Consider the alternatives of living in the lowest caste, needing to do the hardest work, eventually also risking your life, if there was a chance to ascend to a higher caste that would significantly increase living standards. **Honour** Similarly, if there is great honour associated with the status of being an approved mage, this may also be a point at which the increase of social standing (not necessarily an economic one, that one is covered above) is worth the risk in getting a better position in the social structure, having chances for a more.... prosperous marriage arrangement, or having your neighbours being especially helpful, getting preferential treatment in government, or maybe even voting rights, if the normal population is barred from this democratic right. It doesn't necessarily mean that just the applicant may have a benefit from this. It may be that, even if the attendee dies while he is enrolled in that school, the family of the pupil may still receive the honour and prestige associated with having family members enroll in the school of magic. *They are not mutually exclusive, both reasons can exist at the same time in the same society. Effects may be aplified by a sufficiently widespread/state-supported/state-integrated cult or religion* [Answer] **Society that values sacrifice** The sacrifice in pursuit of the benefit or em-betterment of the state would have been acceptable and even expected in many countries. Many turn of the century nations with nationalism, or even ancient countries like Rome. **Necessity** We need mages, and we need them now. We really do not care how many die as long as we get mages to hold off disaster x. **Children should neither be seen nor heard** It has been argued that western civilization did not truly care about children until post WWII, and that children were seen more as a necessity (retirement) or a burden. So as foreign a concept as it may be today, the loss of a child may not have mattered to many. **High Mortality** People die a lot in this world. If I have 10 kids (from 2 wives who all die in childbirth), and 5 die before the age of 18 I may not care too much about just another dead child. It just means I have to get out there and have another kid. **The Strong Survive** Many societies practiced infanticide, where weak or deformed babies were killed. Famously, Sparta did this, but it was somewhat of a common practice in the Mediterranean. If they are not strong enough to survive, we do not need them. Life was harsh, and people were pragmatic. [Answer] *Surprised this wasn't mentioned yet.* ## This is [Sparta](https://en.wikipedia.org/wiki/Sparta)! We are a strong people. To be strong as adults, we have to be so from birth. The weak babies are left behind. If needed twice. From age 7 we go trough the [Agoge](https://en.wikipedia.org/wiki/Agoge), be it physical or magical. Not all make it to adults. We are strong for our country. Alone we are weak. Alone we are without meaning. We live for Sparta. Sparta is live. --- *Go, tell the Spartans, thou who passest by,* *That here obedient to their laws we lie.* *Be their power physical or magic,* *Their death was their honour and duty, not tragic.* [Answer] Culture and advantage. Perhaps the parents all attended the school themselves, or tried like hell to get into it, with the urging of their own parents. Say that getting through the school sets up the kid for a rich life of influence, prestige, fame. Why do parents in the USA allow young children to attend gymnastics schools, to become Olympians, despite the very real (and often realized) potential of breaking bones? (Or similarly dangerous sports). For fame and glory and a short career that can set them up for life. Why do parents bring their kids skiing, when skiing is dangerous enough to kill people, including kids? Just because it is fun? Why do parents consent to surgery for kids that might kill the kid, when no surgery just means continued disability? Because they are betting their kid's life on a better life **instead** of a lifetime of disability. It beggars imagination to claim parents will not complain **at all**, but if releases are signed and informed consent is given, their complaints will be limited to grief (or potentially illegal vengeance if they feel they have been wronged). Minus magic, the **only** way to plausibly have parents "just accept the loss" is to ensure the parents do not love their children at all, that parents view children as property and an expendable resource, to the point that losing a child is no worse to them than losing a car in an accident. From an authorial point of view, I would find it very difficult to sustain reader interest in such a cold and heartless society. No matter what gee whiz magical imagination you might have, such a society would be too weird for me to suspend disbelief long enough to finish the story. One alternative, using magic: Magical forgetting. As part of enrolling their child in the school, the parents must first voluntary agree to forgo any grief if their child is lost in the process. A spell (that requires their consent) is placed upon them immediately. Nothing changes for them, but in the event their child is lost, the spell kicks in when they are informed. They are advanced magically through the stages of grief to acceptance of the loss, love of the memory of their child, their bravery in pursuing the dream they loved. Sad but magically over it, in a few minutes. [Answer] Until fairly recently, it was **normal** for a family that only a part of the children reached adulthood. Child mortality for most of human history has been quite high, often exceeding 50%. If your kids have such a high chance of dying from disease, hunger, war or a dozen other threats, adding a 1-2% on top of it really doesn't make so much of a difference. If what they learn gives them, or even better: The whole family, a sufficient advantage, parents would absolutely be willing to take the risk. It might even be that they don't think of it as a risk. In a society with high child mortality, there are no "helicopter parents" and risks are judged differently. A dead child would not cause anyone to question what the parents did wrong - it simply happens. A lot. [Answer] **Surplus of Population** Perhaps your society is very fecund and/or resources are few. When families are having six or more children, and the average family can feed four, it makes sense to push your children into more dangerous situations where they might gain reward. If they succeed, they've improved their situation, and perhaps yours. If they fail, that's one less mouth to feed (although, of course, there's also a loss in terms of resources invested in raising them and providing for them to that age). [Answer] TL/DR: hero worship and greed. Question: What circumstance would produce a society filled with parents willing to let the children be exposed to life-threatening Danger? One RL Answer: Professional sports. Justification: Every year, little kids die or are permanently disabled in pee-wee sports (especially American football). And hardly any of the survivors go on to get scholarships, much less become pros. Yet parents happily let their kids (especially boys) participate. Why? First, because of the human nature of the kids. Many kids want to emulate their heroes, and also like to take risks. If they don't get to do it supervised, they will do it unsupervised. Second, parents (and the kids) are seduced by the promise of gold at the end of the rainbow, especially if the kids seem to have unusual athletic ability. Third, some parents live out their own dreams vicariously through their kids. So, using this as a guide, your world's parents would send their kids to a slightly-dangerous magicking school because it might lead to fame and fortune for the kids. p.s. I don't mean to imply that pee-wee sports are particularly dangerous! Like I said, they are probably less dangerous for lots of kids than what the kids would do if left to themselves. [Answer] **Non-Magic People have Problems** If people unable to use magic are pretty much at the mercy of those who do, get eaten by magical monsters reasonably often, or have some other serious life problems people with magic don't need to worry about parents might be willing to put their kids into a lessor danger. **Families of Magic User are Very Well Off** If not dying at this school guarantees the family will be rich for several generations it might be a prudent choice to gamble a child's life. **History** Look back a couple hundred years or more. Fair numbers of children were employed or apprenticed in occupations with non-trivial hazards. [Answer] Although a lot of answers already, they are somewhat repetitive in terms of benefiting the family directly (kids make them rich or equivalent) or indirectly (reduced chance of untrained mage accidentally killing them). I propose an alternative: **make mages *feared* and *shunned***. Maybe shunned is a bad word, but mages are a breed apart: a mysterious and powerful group whose abilities wall them off from the muggles. As for prior art, this situation is played out for dramatic effect in Marvel's Xmen (both comic and movies). Most of the parents are all too glad to ship their little muties off to Xavier's. No awkward convos with neighbors, constant fear of discovery, etc. etc. You may wish to make the mages *important* (in opposition to the xmen precedent): they are a consolidated unified group that's too powerful and organized to mess with, but all the more feared and covertly despised because of it. That too has some valuable story arc material: their situation arouses the jealousy of the powerful, allows for dissenting factions in the mages group itself (we should rule vs. isolationist vs. benign interventionalism), political intrigue as different polities vie for the mage's favor in intervening in their favorite local war, etc. [Answer] If lack of magic knowledge would lead to the children dying at a higher rate, then sending them to a potentially deadly magic school would be the lesser of two evils. Just a suggestion - Harry Potter has overplayed the magic thing, so if you want an interesting and fresh story that doesn't come off like a hogwarts clone, you might consider some other skill to be learned - telekinetic or some form of mind over matter thing. [Answer] ### Coming-of-age Rites Possibly the idea that, like puberty, a child "comes of age" when magical abilities are learned. So, while they might appear and possibly have the intellect of "children", because their magical abilities have taken fruit, this is the point in this society where they are considered "adults" and must be sent to school to prepare for the harsh reality of the world. ### Weeding out the weak As a scenario, this might evoke "Hunger Games"-type dystopia, where refined magical ability is required to perform survival tasks. For example, a scenario: As part of humankind reclaiming Earth, children are sent to school to hone and practice their magical powers so that they may aid in clearing out the monsters and creatures that once overtook the world and forced humanity to live in small pockets preserved by magical barriers. The ones who do not survive the magical training were only meant to be a burden on society at war, anyway. [Answer] I have decided to expose my children to danger because in the United States we have decided that driving a private car on a highway is the only way to reach some destinations. Every year many children (and adults) die this way, but there are basically no complaints because we accept it as the way it is. [Answer] **Lessons from Anti-Vax: Ignorance, Misinformation (& Autism)** The Anti-Vax campaigns taught us many things about misinformation, ignorance of science, and the impact of social movements. You can also roll in there the fear of vaccines causing autism - how a single non-reproducable study spread such a widespread and ill-founded outrage. Perhaps in your world, there are incorrect and ignorant beliefs about magic. **Ties to Religion & Culture** Just about anything in culture can be seen through a religious lens and have its own bend. Take your pick here. Culture is much the same, like the practice of female castration [[0]](http://www.dailymail.co.uk/news/article-2871016/She-took-hold-rusty-knife-started-hacking-away-Circumcised-NINE-woman-fighting-stop-female-genital-mutilation-Australia.html) , or other genital mutilation practices. **More Sinister Conspiracies** Perhaps there is a power in control (or seeking it) who is purposefully manipulating the people. This can be a more subliminal thing like the psychological tactics that marketers use to induce consumers to purchase products. It can be a darker or more covert thing like fake news or false information to influence public beliefs, incite anger, or distract the public. Perhaps it goes even darker than that, that these schools are getting too wealthy a profit, that the cemeteries are in on it too, and that the banks love foreclosing on these education loans. Some movies along these lines are : Daybreakers, Thank You For Smoking, The Big Short. Maybe one wizard has a contract with Chutlu and needs the human sacrifices... (See South Park episode Brittney's New Look). **Toxoplasmosis, Nematomorpha, Yersinia pestis** 2 parasites and a bacteria that influence host behavior one way or the other to benefit itself. Toxoplasmosis [[1]](https://www.theatlantic.com/magazine/archive/2012/03/how-your-cat-is-making-you-crazy/308873/) causes humans to behave in a manner that influences cats to bite them to spread to more cats. The second [[2]](https://en.wikipedia.org/wiki/Nematomorpha) lives inside preying mantises, consuming them until they are an empty puppet and completely controlling them. The last [[3]](http://www.npr.org/sections/goatsandsoda/2017/06/29/534863486/the-bubonic-plague-is-back-this-time-in-new-mexico) is responsible for the outbreak of Black Plauge in New Mexico, it influences its host fleas to behave in ways that get it eaten, so it can spread. **Multiple Reasons: Everything is tied together** In our day, just about everything is tied to everything else. For example, right now depression is on the rise and this can be linked to obesity, high average consumer debt, etc. Do not be afraid to draw from multiple reasons from multiple areas. [Answer] What about the simple argument of "who dares wins"? going out of your story and into ours, risk takers tend to be the ones who created airplanes, discovered new lands, gone up to the stars and down the oceans. These people were not raised in bubblesuits by helicopter parents. Also, look into the activities that kids used to do that were acceptable before (maybe are still in some more "primitive" societies). Like learning how to hunt an ill-tempered mammoth, or fish in a shark-infested bay on the top of a tiny canoe, or climb up a tree for fun or profit, or country ski by yourself for miles just to get to school. I am not saying those people acted like life was cheap, but that if they did not have the natural skills and/or did not put the effort to learn said skill, they would not go very far. Incidentally, one of those skills would be common sense: knowing the line between brave and stupid. [Answer] Two answers to this one the first is situation specific; parents being willing to put their children into a magic school where the stakes are so high is perfectly understandable provided the profession is sufficiently rewarding to justify the risks of training. My second answer is a more general one and comes straight out the works of Frank Herbert. In *The Dosadi Experiment* there is vast population pressure and people routinely die in huge numbers due to political manipulations aimed at balancing food supply and the demands of the population. In this situation willingly putting family members in harms way is actually a loving gesture, it denies a lever to those who would otherwise manipulate the family. In the story this extends to the point of volunteering children for suicide missions. If you create a situation where there's enough external pressure aimed at people through their family they'll willingly enough give up those attachments, on the surface at least, to shield themselves *AND* those that they're putting in harms way from what they see as more immediate and concrete threats. Children sent to be mages *might* die but the local lord *will* kill those who don't co-operate with the mage-clergy. There's a third answer in David Brin's *Glory Season*; in a society that is fairly stagnant and where younger children who don't stand to inherit they are basically a waste product unless and until they can carve out their own place in the world. There is a historical precedent as well, in the Middle Ages in Europe first sons of landed families inherited, second sons went into The Church, and any other younger sons learned a trade or joined the military as a path to success outside the family money and lands. If there's no room for success at home it's worth the risk to leave and look elsewhere. [Answer] Any society where everyone in the family unit is already in serious danger of dying, and especially where kids are regarded as replaceable, will produce parents with that attitude. The circumstances in early Australia for one. My mum has mentioned reading in the diary of one of her ancestors where she wrote that the boys (early teenagers) were going to take the cattle droving to look for feed for the next year or two, and her worry that she probably would never see them again because the journey was so dangerous. (Even if they were successful, they would not be able to return until the drought had broken and there was enough feed on the paddocks). I understand that conditions in some areas of India and Asia are such that children get sold as slaves so the parents have enough to feed themselves and the other kids, or where girls end up as prostitutes from the pressure coming from some of their siblings dying from lack of food so they become prostitutes to support the family, then when they get pregnant get disowned because of the social stigma (in countries with no social care). I have heard that the cost of purchasing a slave is less relative to average income then it has been in past history - so the gap between the haves and have nots is probably getting worse not better. (Slavery being obviously a high risk for the slave) [There are are enough real world examples to model] [Answer] **Existential Threat** The children aren't learning magic so that they can impress each other with parlor tricks, win friends, and influence people. They're doing it, and facing life and death situations as part of doing it, because there's an immediate need for proficient magic users to fend off the coming darkness. Anyone who cannot survive the training would be unable to survive the actual "battle" (or whatever dark forces comprise 'the coming darkness'; perhaps evil just pervades the magic energy permeating through your world, and all those who cannot resist its corruption either die or go insane and need to be put down by the time they turn 18 anyways). There's no sense in (and no time for) mourning people who were just going to die anyways. Better that they die early and relatively painlessly than face death by slow decay into darkness. **Eugenicists/Social Darwinists/[Nietzscheans](http://andromeda.wikia.com/wiki/Nietzschean)** Your society is populated by people who believe in and are striving towards producing the most genetically perfect society possible. They want to be the world's (or the galaxy's, or the material plane's) most proficient magic users. Weakness is death (quite literally). Anyone too unfit to survive magic training is weak, and must be cast aside. They have no place in the perfect society, and not only is their loss not sad, it's even cause for celebration because by dying an early death they've ensured that their inferior genetic material has been removed from the gene pool. In death, they serve the perfect society in the only way they can. Their sacrifice can be commended, so long as their weakness is acknowledged and universally abhorred. **People Already Do** It bears noting that the value of safety is *already* a relative thing in real-world society. Air travel is relatively safe, but every trip technically involves life-threatening circumstances (being high up in the air in a thin metal tube packed full of highly flammable liquid) and there are fatalities recorded every year. Although most parents would have no qualms with taking their children on an airplane. Cars are significantly less safe than aircraft, though are still used routinely by pretty much everyone. Skydiving *will kill you* if anything goes wrong, and things do occasionally go wrong, but people still do it and even bring their children along voluntarily. There's a certain threshold of risk that people are willing to accept. Both for themselves, and for their children. That threshold tends to depend upon a few different factors: * **Statistics** - What proportion of students actually die? If it's "several" out of a class of 12, that's pretty worrisome. But "several" out of a class of 100 or 1000? Not so much. Death can be written off as an unlikely prospect in that case, or maybe even something that the wealthier parents hedge against by throwing their weight around, "just give Junior a pass in 'Dangerous Magic 101'" style. * **Utility** - What is gained by taking the risk? Is being able to use magic useful? Essential? Or just fun but with no practical real-world benefit (apart perhaps for bragging rights)? People can and do risk their lives for all of those categories, and the amount of risk they'll tolerate tends to increase as the amount of utility increases. If non-magic-users are shunned or effectively reduced to non-persons or slave-labor in your society, that's an adequate reason for most parents to tolerate the risk. * **Desire** - Who wants to do the risky thing, and how much do they want it? If Junior is terrified about learning magic because they don't want to die, it's less plausible (though not impossible) that their parents would force them into it. If, on the other hand they've grown up seeing magic users all around them, and it's regarded as a major rite of passage, and they think magic is the coolest thing in the world...then good luck to any parent who tries to tell them that they can't learn it because it's "too dangerous". They're not going to listen, and if they're going to fool around with magic anyways, it's far safer for them to do it in an actual magic school than to just start experimenting in the garage or wherever. The only pitch a magic school needs to use on safety-conscious parents is "self-taught magic learners have a mortality rate of 2 in 5, our state of the art magic school reduces this to a class-leading 1 in 10!". So basically, make it something that the kids want for themselves. Have it integrated into the social fabric to the point where that desire becomes irrepressible and practically dogmatic. Make the benefits of learning magic (and/or the costs of *not* learning magic) high, and put the risk level at something reasonably palatable that allows the survivors to look on the dead as "the unlucky ones". So a death rate that's closer to 5% than 50%. [Answer] The obvious: life is dangerous, and you're more likely to survive if you have magic. One example would be a 'life in space' type scenario... a mistake on a spacewalk could be deadly, but never learning to spacewalk would threaten the survival of the station. Another way to look at it is something like an 'Attack on Titan' type scenario where there is an overpowering enemy that the civilization is facing... that creates a strong motivation to have a strong military, and a strong societal norm to put children into the military. you can look at modern day Israel for some example of this... it's legislated for all Israelis to serve in the military when they turn 18. A third example is like some people said a car... it's dangerous to drive (lots of people die every year in accidents, and this does tend to be weighted towards teens as far as I know) but not *that* dangerous (individual chance of being in an accident is still low enough that most people won't be in one). This doesn't even require that dangerous an environment, really. Combine these with human hubris/Dunning-Kruger for (at least) an illusion of control (e.g. 'this may be dangerous for all those OTHER stupid people, but I am careful and it won't happen to me/my kid') and it's easy to do. [Answer] Drugs. Simply they are too stoned to care. **Update with More Info:** Imagine a society where that genetically adults are highly prone to a particular drug addiction. The drug has no effect on pregnancy other than passing on the addiction to the child. Children and teens remain unaffected, but in the mid to late 20's adults develop an extreme craving for it (they are already addicted to the drug since birth, but the symptoms do not appear until their 20s). The withdrawal symptoms include psychosis and paranoia... essentially leaving them unable to function in society without a regular fix. Adults that are high on the drug are able to mostly function "normally" but have limited memory and below average IQ. They tend to forget about their children and other family members unless they see them regularly. They can function in jobs, but are mostly limited to manual labor and menial tasks. Often its the teenagers who provide the job management... such as determining which crops are best to grow in the field for the next season and handling the trade transactions for the village/town. The mages are a different story. Any children that are shown an aptitude in magery have a chance at MUCH better life. Something about using magic minimizes and once a certain level of magic is reached it fully negates the effect of the drug. But on average only 1 in 80 young children will reach the level of breaks them free of the drug. While most students die during the wizard training, there are others that just flunk out. They develop a stronger tolerance to the drug which allows them remain sober a few more years. Often they become teachers in schools for young children and teenagers until they can no longer resist the craving, and fall into the same pattern of their parents. Something about the drug is also essential to procreation, or maybe its magic that negatively affects the ability to have children. Regardless, students at mage school can have children, but a child born to a parent after they have achieved full wizard status is extremely rare. This creates a society where all groups are highly dependent on each other. [Answer] Ours? Children cannot be mollycoddled any more than they can be kept in sterile environments. Some exposure to reality is necessary to survive in it. [Answer] An alternative way of stating this is "What conditions would encourage a specific voluntary behavior within a society?" I think this is a better way of looking at the question, because any behavior is the result of a cost/benefit balance. If the expected cost (price\* probability of failure) of a behavior is low in comparison to the expected gain (value \* probability of success), there is a net benefit. In the case of parents, for there to be universal acceptance of the loss of a child sent for specific instruction, the value of that learning would need to be high compared to the likelihood of failure, AND/OR the value of children would need to be low. In a society where multigeneration families worked to support their family, children would have higher value to each family, than in one where children could be expected to move away as they became adults. "Losing" an offspring would be a cultural norm in the latter. Sending a child to magic school is no different than sending a child to college to learn any other trade. The child may fail at any time after starting. To a society makes more sense to have one fail completely early than to spend a lifetime doing something poorly. Children only have high value to their parents if those parents get something in return for the amount of work expended to raise them. [Answer] 1. Parents can only have one living child. 2. If your child dies you can have another one. 3. When the child reaches a certain age they put through a life or death challenge. 4. After the challenge the child's parents are no longer able to reproduce. Points one and two can be caused by some sort of limited resource. Point three can be caused by some sort of endemic disease or custom or social problem. Point four can be caused either by the parents death or the passing on of some sort of limited resource. [Answer] **A society filled with a combination of carelessness(a form of sloth), lack of love and justice, and in somewhat way, lack of temperance(some sort of greed);** **A sort of delusion(a form of pride) that it's good for the collective(be it country, etc.), motivated by greed(out of which, results that are obtained can be deadly) and those results are generally bad.** *That type of society would probably end up dead in 50-100 years(that because it simply collapses, or people's mentality change, and thus only the bad mental state would disappear, society would get a restart and possibly thrive).* *As ficticious as it is, to have such a society and have even have a 0.05% chance of mortality is not good. It denotes progress made out of greed. Progress made out of greed lacks wisdom. No matter how good the progress, time after time you would have to turn back, to fix the mistakes, in order to go and learn in a better way.* As for anything that would create any of those bad qualities(sloth, prideful collectivism(patriotism) for the sake of greed), possible causes are greed sustained by bad PR(consciously), and publicity that would support such oriented slogans (unconsciously) (e.g." Do it for ... !" ; "Smoking destroys pregnancies!"(on cigarretes), while people smoke without a care in the world;-> which proves irresponsibility). Fixing both the conscious attitude and the unconscious attitude would solve those problems. As for how, probably a group of people with strong core values would stand up for the rights of those people and protect them. [Answer] A society that needs to develop a new collective instinct, perhaps because they've lost theirs and know they need to find a new template, or because world conditions have changed so drastically new instincts are needed, could account for both the high risk taking on the part of the parents and the need to expose the children to danger as part of the program. Great question :-) [Answer] Actually, what you're describing has been the most common case in societies on Earth. It has only been recently, and only in some parts of the world, that people started to value life so much. It used to be that women would give birth to children for all their fertile period of life, sometimes dying in the process. It was not uncommon to have more than 10 children. The fact that some would die for whatever reason, was kind of known to be a part of life. If especially becoming a magician is considered to give some priviledge, or that you will be held in high regards, or that it increases the honour of the family... I can imagine people would accept the trade off. ]

[Question] [ This excludes metal stakes, knives etc. to the heart, it's not the bleeding out that's the issue. Just for some reason, a *wooden* stake to the heart ends a vampire. Why? Assume the type of vampire that is common in fiction (can't go out during the day, doesn't like garlic or crosses, but can pass as human), no Twilight sparkle people please. Vampirism in the context of this post is spread via a transmittable virus that lives in saliva and blood. [Answer] Now, a few answerers have claimed that the stake need not be wooden. While this may be true in the traditional vampiric lore, we exist only to answer the specific question here. **Why Wood** Vampire Blood contains a specific set of proteins and nutrients that allow for almost instantaneous regeneration. These proteins are denatured by heat (fire), and cannot re-attach a separated limb (head). As metal and stone stakes are not organic, they could not possibly prevent the regeneration factor from doing its work. Bone also is not effective, as the regeneration factor cannot penetrate the cortical layer on the outside of bones. Wood is therefore the only readily available organic stake medieval peasants would have access to. When the wood is stabbed into the heart, tiny particles break off and are quickly spread throughout the bloodstream. The regeneration factor acts on these particles, causing thousands of small blood clots and massive internal bleeding. If further damage was necessary to kill, blood clots will soon reach the brain, causing massive strokes, rendering the vampire unable to fight back. Wooden stakes to the arm are not as effective, as the particulate does not spread as far and as quickly, allowing the vampiric immune system to react and destroy the particulate. Now, you could make a stake out of compressed and baked kelp, or algae, or some other form of organic matter, but who in the world would think of doing that? The only way we found out that wood does the job is through sheer chance. As very, very few people carry around farming implements, weapons, or tools made of non-wood, non-bone organic matter, it would take an enormous amount of time for such a kill to occur by accident. A kill with Wood would (lol) only require that a farmer's hoe, or a labourer's shovel, or a soldier's spear to break and be used in a desperate attempt to save one's own life. [Answer] It's due to the nature of vampires, and their regenerative state. If a metal or other non-organic substance is thrust into their body then over time their regenerative abilities will push it out. Even if they are completely impaled the stake will gradually migrate as the body moves to one side of the coffin or the other. Use a material that was once alive though (wood is most common but bone would also work) and the regeneration extends to that material and causes it to fuse with the body and trap the vampire in a disabled state. Wood is ideal as over time it actually sprouts roots that spread through the vampires body and immobilize it permanently. [Answer] Regardless of what Hollywood might tell you, the stake doesn't have to be wooden, nor does it actually kill the vampire. The tradition is that to prevent a vampire from rising they need to be staked into the coffin, metal stakes are acceptable, but wood is cheaper and more readily available to the average superstitious peasant. Also reference can be made to the true cross being wood. Removing the stake allows the vampire to rise again. If you want to kill a vampire you need to cut off its head (stuffing with garlic optional), burn it, or expose it to sunlight. [Answer] Any scientific reason would have to be in the make up of wood itself: See [The Chemistry of Wood](https://en.wikipedia.org/wiki/Wood#Chemistry_of_wood). Perhaps because wood was living cells; something the cells produce; everything from sugars (like in sap) to cell walls -- or a "recipe" of such products in a particular balance. Think of a chemical recipe as producing a kind of molecular machine, and a machine that won't work if any element is too much or too little: Just like a cake won't rise correctly if it has too much or too little liquid, flour, baking powder, salt, sugar, etc. Or the science can be in the actual DNA of the wood: DNA and genes are physical things, and the DNA unique to woody plants could be the machine that is causing the vampire death. In this case for vampire lethality, "wood" must have a precise combination of cellulose, lignins, and other atoms in precise position and combination to cause an interaction with the vampire heart that degrades it and poisons the rest of the vampire system. If you want the vampire to be dusted, "Scientifically" we'd say whatever biological compound was holding the vampire cells together was defeated by the wood, and the unraveling of each cell causes neighboring cells to unravel: thus a massive chain reaction that unravels every cell of the vampire, effectively turning it to dust. Such chain reactions are not unusual at all in chemistry. Why the Heart? Well, the heart is obviously specialized cells that do not occur anywhere else in the body; so it has something to do with the nature of those cells. Perhaps they are uniquely vulnerable to the effect of the wood, the only cells in the body with the particular atomic configuration that the wood "fits" on the ***outside*** of the cell; so just touching wood gets the wood "recipe" inside the heart cell; where the cell replicates it (like a virus) to the point of rupture: then the physical force of that rupture infects other cells, which rupture, and voila! exponential growth of a disintegrating core; a chain reaction. Of course if there is science, there is a chance of isolating the compound in wood (by experimenting on vampires, or vampire heart tissue), so something like steel stakes or bullets could be coated in it; which might make for easier delivery. But it still must come into direct contact with a (formerly) beating heart cell, so must penetrate the chest. But something like bullets might be needed if a vampire had (through surgery) encased his heart in a hardened steel shell. Vampire hearts typically do not beat; so they don't circulate blood. So a wooden stake elsewhere in the vampire body touches no heart cell, does not circulate to the heart, and therefore the special ingredient in wood causes no disruption. In fact other cells could metabolize that wood compound (break it into pieces) and render it harmless. [Answer] I'm going to riff on Tim B's answer and say it's about the vampire's regenerative process, which creates highly localized, intense heat. Normally this isn't a problem, but you add intense heat to wood, and you get... fire! Once the fire starts, it produces the small energy kick needed by the initially-endothermic reaction to oxidize the rest of the vampire's cells. A chain reaction ensues, which is why the movies that get it right show vampires crumbling to ash when staked. Even if you pull the stake back out very quickly (because whittling a stake per vampire takes too long) enough microfibers are still left behind to kick-start the reaction. **Edit:** Of course this begs the flamethrower question (w/ a nod to Kaine's comment). If staking actually causes a vampire to die by fire, then why isn't a flamethrower a viable weapon? Here it gets a little more complicated. First, when the flame is applied externally, there is the chance for some of the heat to dissipate into the air. Plus, those buggers are *fast*. So an initial blast of flame will certainly damage them, but they'll move out the the way fast enough to avoid the start of the chain reaction (and the movement itself will help dissipate more heat). Of course, if you could tie a vampire down and hit him with a concentrated blast of heat, then yes you could spark the chain reaction. But practically speaking you'd have do to that when he's asleep during the day, and getting a flamethrower past a vampire's minions is a lot harder than tucking a stake under your shirt. [Answer] The question sort-of implies that you're looking for the unique combat advantages of wood, but if there's no magic, it would have to somehow be super-poisonous to a viral infection, which would be pretty silly. But! stakes were traditionally used to prevent vampires from reanimating; it would be driven into a corpse's heart as part of burial, or reburial. The vampiric virus' goal is to knit the body together into a useful, mobile state. Stakes interfere with this: * Regenerating skin would be a good first step towards reanimation: control decomposition and thwart scavengers. Having a pole stuck through the torso would be a big problem. * Reestablishing blood circulation would be another top priority; the stake in the heart would greatly complicate that. * The stake's wound would be septic. Even if the heart managed to start pumping, it would spread putrefaction. Wood is cheap: burying a golden (or even iron) stake in every corpse is too expensive to be practical (in 1200AD). Metals would be stolen by grave-robbers; not wood. Wood is tough enough to last until the body is sufficiently decomposed to be useless to the virus. Wood is strong enough to pound into a leathery old corpse. [Answer] ## Actually not **all types** of wood will kill vampires... that's a myth. Only some woods that have antifungal and antimicrobial properties are necessary to combat the vampire virus. This is the same reason that garlic repulses vampires, because of the antifungal/antimicrobial properties of garlic oil. Also "holy water" is really just water that sits in a cold stone container for an extended period of time, which allows it grow a mold that has antimicrobial properties. It doesn't actually have to be blessed by a priest to kill vampires. And the whole thing about sunlight is that the vampire virus changes cellular structure to create a massive increase of vitamin D receptors (VDRs) on the cells. When the VDRs are overloaded, the mitochondria actually produce an intense burst of heat, then the vampire burns due to the wick effect of its subcutaneous fat. see wikipedia: [Spontaneous human combustion](https://en.wikipedia.org/wiki/Spontaneous_human_combustion) [Calcitriol receptor](https://en.wikipedia.org/wiki/Calcitriol_receptor) **A little known fact is that you can also kill vampires with any oil rich in vitamin d, like fish oil!** Here is a specific type of wood that has anti fungal properties that actually does kill vampires: <https://link.springer.com/article/10.1007/s00226-011-0428-9> Also willow stakes are effective: <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1779808/> [Answer] This was explained in the novel "I am Legend". Googling found that this detail was explained in chapter 17. The reason stakes kill the vampires is that they allow air into the body. It also "keeps the flesh open so the body glue can't function". Normally any wound like a cut or bullet hole would be rapidly closed by that "body glue" explaining the vampires' durability. Penetrating the heart is unnecessary for this reason in that novel. Wooden stakes work better as they are more porous. Via this explanation, other things feasibly could work like an air compressor and pipe, but a metal spike would clearly work less well (as the glue would just seal around the wound). As you can tell, vampires in "I am Legend" are a little different than other media and are somewhat reminiscent of zombies. Nevertheless, it gives a scientific explanation (sometimes good) for many of the vampire myths. [Answer] All of these other answers are trying to come up with ways in which wood could stop regenerative powers or why wood would be better than other materials. But that's not what the question as stated has asked. It asked if there is a scientific reason why a wooden stake is the ONLY option to kill a vampire. And for that question, you need not even consider how the wooden stake kills the vampire, you need only consider why literally every other means of destroying the vampire would not work. And to that question, of "is there a scientific reason why a wooden stake would be the only way to kill a vampire?" the answer is a resounding "no". There is no scientifically plausible way in which a vampire could regenerate from or remain unharmed from the myriad ways to destroy something. You can't have something that is immune to heat above a certain temperature, or immune to being cut up into little pieces and each piece being put into a box, or immune to pressure, or immune to every form of dissolving chemical reaction, or immune to sufficiently powerful explosives, or immune to starvation of useful energy, black holes, or, in the very long run, to entropy. There might be some scientifically plausible way in which using a wooden stake to the heart is the easiest surefire way to kill a vampire, but that's not what's been asked in the title question. [Answer] When I first read Bram Stoker's Dracula, I was amazed at the highly rational, scientific way that the English heroes and their friend, Dr. Van Helsing, coped with the object of a Medieval Catholic myth in their travels. Van Helsing investigated Dracula in the same way that any Victorian scientist would examine a phenomenon of interest - say a diversity of finches on a distant archipelago or measuring the speed of light. Science is as science does. So, scientifically speaking, vampires are Christophobic. They shun churches, holy water and crosses. Van Helsing "contaminated" Dracula's coffins by placing consecrated hosts in them. In traditional Christian myth, all wood is considered sacred, because related to the wood of the Cross --- ergo, dangerous to vampires. Is this a scientific explanation? If we are talking about vampires, this is as scientific as it is likely to get. To me the big question is "why garlic"? [Answer] **Wood is not necessary to kill, but it is the only safe substance to verify death**. You can kill a vampire with literally everything piercing the heart, but only wood causes involuntary spams which are quite dramatic (and cannot be faked) and only cease with death. The problem is * that killing a vampire with staking does not change their appearance like decaying into dust or going into flames, so you do not know if they are dead and * that the vampire heart is quite robust and the life signs are extremely hard to detect, so vampires could fake death if you don't hit the heart exactly. It only takes a few times for vampire hunters to know that approaching a vampire without knowing if it is dead is extremely foolish. So if you hit a vampire with a wooden stake in the heart, (s)he spasms and when the spasms cease, you know (s)he is dead. The vampire also spasms if you hit him with wood into other body parts, but the spasms are weaker and can easily be explained by pain or nerve damage of normal people. [Answer] So many answers... A fun thought is that since the wood was once living, the virus "re-animates" the wood and grows a tree if it finds the right part of the vampire's body (the heart). Since the tree was so much more massive than the vampire, the energy required to re-animate the vampire gets sucked into growing the tree and the vampire remains motionless. It could make for a good sequel - the blood forest or whatever. [Answer] I agree with [@Separatrix](https://worldbuilding.stackexchange.com/a/89999/23503) that the wooden part may be optional. From a pseudo-scientific point of view, staking the heart may be used to stop the vampire from regenerating. As cutting the head off lets you eliminate the brain of the vampire and kills of the body, stopping the heart may stop the vampire itself. Now, undead vampires are often described as having no pulse, but that makes sense only in a more "magically explained" context. From a more scientific point of view, all vampires still need blood to survive. It is only natural to suppose that this blood is carried around in veins and arteries. Since blood is the source of power, stopping the heart would mean stopping blood flow - so movement, healing capabilities, strange vampiric powers ... the vampire itself may not die and fall into a dormant state, if you wish, but if it can't move it's almost as good as killing it (bonus points: it's easier to cut off its head). **The important thing is that the vampire should not be able to remove the stake by himself.** Bonus points, maybe wood also *poisons* the blood, making the heart stop faster or impairing movement better on elder/more dangerous vampires. [Answer] I am going to take some liberties here with the concept and definition of 'vampire'. Apparently, from what I read, it has been clarified that you are NOT speaking about a 'generic' vampire, but a specific concept that can be modified to suit the requirements. That is, a human body that has been taken over by a virus, which is somehow able to maintain homeostasis and muscular function in the host body without the host body itself being alive (else killing the host body would kill the 'vampire'). I am also assuming that such concepts of 'sentience' and 'memory' in the host are moot points. More a zombie than a vampire - or a cross between them. It is having a moving, semi-functioning body that is important, not any other human characteristics. It, of course, begs the question be asked 'If you cut off the head of a vampire, does it still retain its memory and personality?' I am assuming the answer to this question is moot. The virus somehow becomes the personality, and if there is a brain left in the host, than the virus can somehow manage to keep it functioning in some non-living way enough for the virus to 'read' it. But, of course the destruction of the host memory and personality would not result in the death of the virus. In which case, the question is not how to kill the vampire host, but how to kill the vampire virus. Since a virus can spread throughout the host, it would imply that any part of the host that remains could potentially contain live virus, which would still be able to reproduce and 'control' the host. That is, it is the virus, and not the host, that actually lives on. This would assume that if any small part of the virus lives, it can propagate again to 'infect' the entire body, or whatever is left of it. A walking hand, where the muscles are systematically triggered by some biological process of the virus? - the virus can either trigger neural impulses in nerves, or it can send out chemical messengers. So if sunlight and garlic were toxic to the virus, they would result in the death of the virus. The question then becomes 'How else do you kill this virus?' Certainly, any sterilization process that can be guaranteed to eliminate 100% of the virus, but we know there are viruses that can survive almost every physical environment, albeit in a dormant state. There are viruses that can live dormant in the human body until the body dies, and perhaps even after. Just one virus in one cell of the former host could potentially re-infect. So why just a stake in the heart? A particular reaction between some protein or other in wood and some cell structure specific to the heart, that produces a toxin that will kill the virus. Perhaps it could even be another virus that lives only in the human heart, that would survive the death of the host, just like the vampire virus. This would assume the circulatory system still functions to some extent to spread the toxin. This could, perhaps, be molded or refined into some concept of a virus that only lives in the human heart, being the only thing that could produce a toxin under specific circumstances that would kill the 'vampire' virus. It is a solution that does not require the host to be alive in any sense of 'human sentience', or of the heart working as a heart. A dead heart could also host the competing virus. It does, however, seem to imply some form of sentience for the vampire virus itself. [Answer] You can't get a plausible scientific reason other than "scientific" one. There are many ways to kill. If you put vampire in a high temperature environment, it will burn(assuming carbon based living organism). If your vampire isn't made of carbon, you can still melt him, crash him, and depending on his body - suffocate, dismember, poison, dissolve with acid, deadly injure, or place him next to strong magnet which would disrupt his cells. There is absolutely nothing unique about wood that wouldn't make it hilarious when confronted with above methods. So, either don't try to explain why and just make it a well-known fact that does not need to be explained, don't use it as a (sole) way of killing the vampire, or come up with *any* explanation and call that a "science" in the real world(which you may read as "use handwavium"). Some of the reasons might be: * Vampires are immortal half-gods, capable of taking ghost form, so killing their body won't stop them for long. However, (one of the) trees contains soul of god that seals the vampire's (whatever it has - soul, ghost, mind), and the (thing that gets stolen) is stored at its heart. * Vampires are built of cells that show some specific quantum properties that make them almost invincible. However, wood disrupts this property. The heart is the place that pumps blood/does some vital thing, so when wood is inserted in the heart, it stops its quantum thing from protecting the vampire's body. Attacking any other part would leave the vampire with enough time to make his quantum backup. Or however this solution works. * Vampires are the only ones that can kill each other, but they need to do so by their bare hands, which is too hard to be a practical way to kill the vampire(they regenerate too fast/escape too quickly). However, they are genetically related to some tree, which allows the tree to be used as a weapon. For the same reason as why vampire can't (in practice) kill other vampire, the wood needs to be applied to the heart. Although there's really no way to do that without using pseudoscience. [Answer] The science behind vampires is that they are actually people who have gotten rabid. Sensitivity to light, aggressive behavior, Intensified desire for lustful passions, fear of water (note water does not actually kill them - hollywood myth), don't eat solid food, (difficulty in swallowing solid food), but do bite others of their own species, don't sleep at night. While the stake through the heart may kill a rabid animal - It does not kill the infection. If the blood of the vampire gets consumed by another animal that next animal will get infected, (about 21 days after exposure) ... thus becoming a vampire. Although most the stories are that the individual vampire himself, at least so far, does not come back to life. According to Hydropathic Encyclopedia, Robert Trall, M.D, Garlic can stop rabies / the vampire infection. Garlic or muriatic acid should be placed on the wound. Since 21 days after, (the stake was suposed to have killed the vampire), a new victim appears clearly the vampire escaped death. How else in the 12th century could he have another victim if he was dead. The vampire must be burned to kill the infection. If we are to consider the science behind the myth. And, yes rabies was present in the populations when the myth started. Yes, bats can carry the vampire infection, but scientifically vampires can be almost any mammal. A vampire that was only killed though the heart can return as a wolf, if he was not burned. [Answer] Possibly the common vampire has a rapid healing factor and regeneration which does not work for the heart. (Either by not being able to heal damage to the heart or by any damage to the heart causing massive blood clots and/or tumour like scar tissue growth.) A wooden stake could deliver splinters into the heart causing infection and exacerbating the problems. [Answer] Personally, I prefer the vampire of Arcane origins BUT, I'll have a go at this. The only thing I can think of that could scientifically justify (as @Rekesoft so perfectly put it) "someone who has become immortal, highly flammable under sunlight, allergic to garlic and cross-phobic due to a viral infection can only be killed through a stake in the heart, but only if it's made of wood" is by a virus of intelligent design! It's maybe something you'd struggle to justify any of your characters even HAVING an explanation for, but if a sufficiently advanced - and probably weirdly religiously inclined - race, be they alien or ancient earthen, wanted (for whatever batty reason) to give mankind (or some portion of it) some weird superhuman abilities and very specific vulnerabilities, a very sophisticated DNA altering virus may be the best/only option. The specific method(s) of killing a vampire (e.g. a steak to the heart) could even be deliberate, hidden kill-switches (just in case). In which case, the stake causes the largely dormant virus cells to trigger a violent pyro-self-destruct mode. This could even explain some of the less well known 'myths' like how stakes made from ash wood are more effective 'just because the virus recognises them quicker', or that vampires are obsessively compulsive about counting and untying knots 'because crazy ancient/alien cultists tried to make mankind act more appropriately' in their own mixed up way. Or you could brush those things off as unintended side effects. Maybe the creators of the virus got bored and left because 'our work here is done' or 'whooee, well that didn't go well, lets try somewhere else', or maybe they were destroyed by there own creation due to an unexpected shortage of timber and heavy overcast from volcanic clouds. [Answer] The following could be used as a plausible scientific explanation. The Vampiric virus causes the body to produce a new enzyme that gives the victim all the traditional vampire powers. This enzyme, though, causes the skin cells to have a violent flammable reaction to sunlight. The enzyme also combines badly with allicin from garlic or cellulose from wood to form a compound that is deadly to the body. As allicin is partially aromatic, it's presence in the air can be deadly to the vampire when breathed in. Cellulose in wood, however, is only deadly to the vampire when inserted into the body. As the heart is the primary organ of storage for the vampiric enzyme, this is where the wooden stake would be most effective. [Answer] Another option is that wood is somewhat porous, while metal isn't (as much). The regeneration can work around and eventually push out a metal object, but enough body material gets absorbed by the wood that the regeneration process embeds the stake further instead of pushing it out. This is only an issue at the heart where there is enough blood to sufficiently soak the wood; elsewhere the body is able to eject the wood before it's gets embedded by regeneration. [Answer] *Vampires are very clever and have the same drive to survive as anyone else, and a wooden stake to the heart is actually one of their reproduction options* One possible reason for wood being the ONLY type of stake material to work is simple propaganda put out long ago by the very clever vampires themselves. The vampires became aware of their own vegetative propagation ability by discovering quite by accident that they have a type of meristematic cell ( <https://en.m.wikipedia.org/wiki/Meristem> ) biology more closely related to plants than animals. This was discovered through noticing repeated occurrences of a wooden staked vampire eventually regenerating many weeks and sometimes months later, whereas none of the metal, bone, or icicle staked vampires ever regenerate. Through experimentation, they found out their hearts just so happen to have the highest concentration of their meristematic cells, so naturally that's the best place to 'plant' the regenerative wooden stake. Like other plants, they also have other less taxing methods of reproduction, but this one works in a pinch. It didn't take long for them to launch a sneaky misinformation campaign out to the non-vampire community (see other excellent answers for good propaganda examples) to ensure active vampire hunters use wooden stakes that will likely allow their eventual return from the grave. As anyone who has worked with plant propagation knows, this isn't always a fool proof method of reproduction, but considering it is actually taking an enemy's intention to kill them and turning it into reproductive assistance, it's really rather ingenious. [Answer] * Cardiac arrest * Acute hemorrhaging * Shock * Infection * Blood clots/stroke Take your pick - ;-P [Answer] **Vampires Are Not Real** If a vampire can only be killed by wood, the obvious question is why doesn't being put through a woodchipper and then baked at a thousand degrees kill them. The obvious answer is that not life form we have found could survive that. Then we may conclude that vampires don't really exist. Never-the-less, vampires might seem very real to the protagonists, and the idea that they don't exist may seem absurd. * **"But I've seen Vampires!"** Some parasites [change the way the host behave](http://news.nationalgeographic.com/news/2014/10/141031-zombies-parasites-animals-science-halloween/). Perhaps a parasite induces hallucinations that manifest based on the desire to see one dearly departed, but corrupted by creeping dread. * **"But there have been many witnesses of the ghouls the vampires have created, and their stories agree, so they can't be a hallucination!"**. The parasite sometimes also induces ghoulish-behaviour. * **"But the ghouls had bite marks!"** The pair of marks are the entry and exit wounds from the parasite. * **"But an entire town was butchered by Vampires!"** Sometimes the Parasite induces violent behaviour, sometime a Vampire cultist hopes that killing and drinking the blood of the infected will give them immortality, and sometimes some serial killer just decides play the part of a vampire for some reason we will never understand. And most importantly * **"So if Vampires aren't real, how come wood kills them? I tried shooting them with a gun, but they just came back. I stabbed one with a wooden stake, and the other took fright and never came back."** Aspirin comes from a tree. If you quickly prepare a fresh wooden stake (or perhaps cross) and wave it round long enough something in/on the wood cures you, and then the vampires go poof! More likely, the cure relates to the process of [fire-hardening](https://en.wikipedia.org/wiki/Fire_hardening) and it was actually the *making* of the stakes cured you, but like most things the cure isn't instantaneous. That is the real reason that the Vampire that was never staked never came back. If vampires are hallucinations that means that although the universe is science based they may appear like supernatural spiritual things that are too horrifying to obey our physical laws (at least until their real cause is discovered). ]

[Question] [ Most human swearing and cursing is based on either bodily functions (notably reproduction and waste elimination) or on religion. In an alien society where there are no taboos along those lines and where there is no religion, what might take the same place as words used for emphasis? These are words to use in anger, to attack other people, or to add emphasis to points. What do these aliens say when they accidentally trap a tentacle in the door? **For more information on the aliens:** They evolved from 6-limbed octopus-like creatures that moved onto land and developed two strong walking legs and 4 manipulator tentacles. They were/are scavengers and are able to eat pretty much anything, so have no real disgust aversions for bodily waste/rotting carcasses/etc. They did have religion but have since moved away from it and are now almost completely atheist, the last "believers" died many generations ago. Technology level is similar to ours, maybe twenty to thirty years ahead of ours. They have some people on their moon and more in orbit but most space exploration is automated probes. All members are hermaphrodites. Reproduction is usually done through asexual means, they can mate and produce offspring with share DNA but there is no particular urge to do so and it's not considered strange either to do so or not do so. [Answer] *"I hope you get (fatal health problem) and crawl back into the (lower lifeform) nest you spawned from and die, you (deformed) (disease)-ridden piece of (low status) (socially unacceptable habit) filth!"* *"(Predator) bite me, I'm cursing too much again!"* Basically, any bad thing that can happen to one (swearing and cursing), or anything that makes one unattractive to potential mates or society at large (cursing only). Note from real life: I live in the Netherlands, where sh#t and g#dd#mn already lost a lot of their effect and are even used on TV (in the evening mostly). "Cancer!" has become a popular (and much-despised) curse word here among the less considerate people. [Answer] **Curses and cursing have trends**. And the society goes for highest taboo which exists. Example from history: 1. **Religious taboo** (medieval) - people used to believe that saying deity name would actually hurt such deity. OK, your setting can skip this 2. **Bodily functions:** Naming people as taboo bodily parts. In our case these are organs used for sexual reproduction and/or bodily functions, namely defecation. While you rule this part out, still there can be body part which is considered taboo and "talk to the hand!" may be purely offensive 3. **Racial and race based:** You either can use slang word for one race as offensive or abusive. Also to this group you can have social status in the group, so "you are beggar" can be also offensive 4. **Mentality and psychological** based (current trend in our society). Any word connected with fact that such person may have low IQ is considered really abusive in our society. **Start with having some taboo** If you are intelligent species, you do not talk about something. We like to have something hidden, because it does not go well with our "perfect" world. Good picks to start: 1. A person who is perceived as negative. Earth example: Adolf Hitler 2. Racially different group, or having caste system in place (beggar versus noble) 3. Notable meme of such society. Examples: Grumpy Cat 4. Historical event which was perceived as negative. Example: Hiroshima, Vietnam War [Answer] Kids cartoons suggest you can use any word, and as long as it is used as a curse word the meaning will be clear. Spongebob Squarepants uses "Barnacles" and "Tartar Sauce" as curse words. Jake and the Neverland Pirates uses "Coconuts" It is obvious they are curse words by the way they are used. [Answer] Insults and swears are not only based on bodily functions or religion, but on everything that can be socially awkward: family (especially moms), mental or physical capacities (disabilities), age or gender... And swears have trends. Joking or insulting people about their sexuality is a thing now, but a few centuries ago, it was more a threat as you could be killed for being gay for example. Same with races. Find what's bad in your alien society: belong to a certain group (family, politics, activists?), have mental or physical differences, or have a badly considered professional or personal activity ("immoral" like prostitutes, or unuseful). Raging with something cute like ponies and butterflies would be ridiculous. It has to be something evil/immoral/ugly/dirty/ridiculous... Pick one and find something that fits in your alien society. [Answer] Since they are aliens they need not even *want* to curse. They might release a pheromone that labels them as injured, or flutter their tentacles when pained, but have no particular vocal urges. That would mean these things serve the similar functions. Reflexive responses might not even affect their consciousness much. That is, a squidcritter could smash his tentacle in the door and respond by turning all kinds of weird colors and/or releasing a weird cloud as he simply pauses in saying anything he was saying, perhaps momentarily distracted while evaluating the damage, before continuing much as if nothing happened. That would make them seem quite stoic, but actually be quite different from human. In that sort of alien culture, the set of taboo words would have nothing to do with physical pain. Of course, even so, an angry squidcritter might use or pantomime the damage sign as an insult. [Answer] Status in the society is another common means of insult. Take for example calling someone "common" has certain connotations associated with it. There is also the inverse where calling someone "posh" is rarely used in a positive way. It could also take the form of racism or xenophobia. Although again, this is likely linked to the status of the group in society. [Answer] Unfortunately, I cannot remember the name of the book(but I *think* it was written by Heinlein), but I remember reading of a similar scenario. In that case, the vilest curse uttered by the advanced alien being was: "Entropy!" because it was the worst imaginable situation for that particular alien race. I imagine something similar would work for you. What is the worst thing that can happen to one of your squids? Losing a limb? Being born with only 5? Whatever it is, turn it into a curse. As an aside, your aliens may not be *offended* by bodily waste but they certainly cannot consume it. I think "eat excrement" would still work, at least as a mild curse, because as waste, it can serve no purpose. [Answer] In addition to actual new topics, I'd like to add that cursewords die quite slowly, at least among humans (tentacles might differ). If you have written history for their tentacle-religion, it's likely there are some remnants still lingering around, probably in form that current day tentacle guys don't even recognize as religious curse words. I use example of Finnish relatively mild curseword hitto. It predates Christianity in Finland, and wasn't really adopted to Christian mythology and vocabulary unlike some other pagan terms. Yet, it still hangs around. Original root was most probably [hiisi](https://en.wikipedia.org/wiki/Hiisi) (meaning sacred grove and later spirits and even giants). Most users have zero idea of the word's origin but it has good cursing qualities with it's strong consonants and shortness. It snaps from the tongue. (Though longer cursewords can work, like [perkele](http://satwcomic.com/a-bad-day), which is 3 syllables, but has extremely good cursing quality.) Especially for expressing anger and frustration, the cursing quality of the word is important. So it's also possible that your tentacle-dudes have nonsense words which have mutated from good old cursewords. PERuna (=potato) is almost as satisfying as PERkele (actual curse word). [Answer] Since you say they moved away from religion, it sounds like it had been for purpose, so someone who is still faithful may contradict with the common society, and under such circumstances I would be disgusted if you would call me an "greenly religios dumphead" Or stuff in such a way. [Answer] Interesting quote by Stephen Fry recently on this very topic. > > Stephen Fry: If an alien was looking down on us and inspecting our > language they would see the worst things we do on this planet is we > torture, we kill, we abuse, we harm people, we’re cruel, and those are > the things of which we should be ashamed. > > > Among the best things we do is we breed children, we raise them, we > make love to each other, we adore each other, we are affectionate and > fond of each other. > > > How odd the language for the awful things is used casually all the > time, ‘oh the traffic was agony’,’it was hell’, ‘it was cruel’, ‘it > was torture waiting in line’ You use words like torture? That’s the > worst word. > > > Yet if you use the F word, which is the word for generating the > species, for showing physical affection to one another, then we’re > taken off the air and accused of being wicked,and irresponsible and a > bad influence to children. > > > Now we’re part of this culture so we often don’t question it, but if > you think of someone from outside… it is very strange. > > > [Source](http://scottberkun.com/2010/quote-of-the-month-7/) [Answer] "you scruffy looking nerf-herder!" "You're one of the sheeple" "moron" "jerk" Almost anything could be used. Comparing someone to anything unpleasant or 'broken'. Which, unless their poo smells like roses, calling someone a 's\*\*\*head' will always be an insult. The thing is most 'cursing' is 'bad' because of religious connotations. So without religion, (any kind) there is no 'cursing'. Now Vulgarity is something else again. Vulgarity is more what I think you are going for. Words and phrases that are offensive. These could still be sex related, 'F\*\*\* a duck', 'necrophiliac', 'Mother F\*\*\*\*\*' etc. While sexual orientation may not be an issue there are still things one could have sexual relations with that are inappropriate. Bodily wastes will still be 'icky' and have locations to put them for waste management (Toss pot). There will also be garbage/trash, things being thrown away that have no more value. Including ideas. > > curse - invoke or use a curse against. > "it often seemed as if the family had been cursed" > > > Vulgar - making explicit and offensive reference to sex or bodily functions; coarse and rude. > > > [Answer] In a society I am familiar with, before Americanisation became the fashion, some **"coarse" words** (or surprise interjections) have been taken from everyday language (thunder, lightning, mother, ...). In fact, many sexual slang has been taken from everyday language, over time rendering the usage of those everyday words in their original context laughable or even frowned upon. Thinking of the original Battelstar Galactica series ("frack"), you could possibly get away with just using any nonsensical word for which you do not need to provide any etymology. If you want to be clever, you could choose such words to carry additional story content (e.g. sarcasm at your favourite cause to heap scorn on, e.g. "politician!" or "lawyer!"). A *bona fide* **curse**, on the other hand, does not make much sense in a *truly* atheistic environment, as it is universally involves the invoking of some metaphysical idea to bring misfortune on the cursed, that the curse would not normally be able to bring about through his own power. But if you are prepared to relax the atheist attribute a bit to still allow such wishes of calamity, you are only limited by your depth of creativity and humor ("may a thousand lawyers pursue you till the universe's entropy death", "may you receive 70 versions of this software in the afterlife" (apologies to Dilbert), "... went on with a suggestion that the [person] go amuse himself in a manner both vulgar and physically impossible.", "Go take a barbed-wire enema..." (both from the writings of Howard L. Myers), etcetera ad nauseam. [Answer] You could have words that were formally names or words which mean things that are still terrible. For example, since the last believers of this species's religion died generations ago, you could use their words for "faith have-er" or "faith having" to describe a person to be ignorant, blind to reality, or unscientific. If this species has some terrible people, there's all kinds of things you can do. For example, "Hoover" or this species equivalent, could mean "lazy leech" or be a vulgar term for "hypocrite". There's probably some actions that are still obscene, which could work as material. "ass-raping" is a vulgar act no matter what language it's said in, what species performs it, or the religion of the speaker is. The same is true for other things such as "theiving", "hypocritical", etc. The same is true for "Horse fucker", since the horse can't consent. You could look to the environment of the species for material. If their home planet is poor in resources, there could be a bunch of vulgar words for wasteful. If there's a lot of unsafe areas, various disaster-related words may have emerged. If these people are not ethnically or politically united, there may be some material there. Derogatory terms may have emerged for other groups. In english alone, we have the N word, all kinds of deragatory terms for various asian groups, "cheese eating surrenders" for the french, etc. You could also use the labels of a single group as a curse word itself, like how the green party is a topic of mockery in west virginia. There's a lot to work with there. There's a lot to work with here. [Answer] This is something I struggled with in my own science fiction comic series, [Unity](http://beesbuzz.biz/d/cat-unity.php). I ended up using corruptions of names which were based on reviled historical figures (the origins of which were never explained in-universe) and things that were found to be unfortunate circumstances but distorted beyond all recognition. I also "borrowed" the expression "jar breeze" from the much-better comic [One Over Zero](http://www.undefined.net/1/0/), although that one has origins in bodily functions. [Answer] Interesting one... I was going to suggest words based around social class, culture or other behaviour, things like "your mother was a hamster and your father smelled of elderberries" or "you sir, are a vegetarian!" but then I realised these are insults, not curse words. So what else would be used when trapping your tentacle in a door, words used here have to be short and sharp. Quick to exclaim "b\*\*\*\*d" or "F\*\*\* this". AS octopii based lifeforms maybe they'd be more concerned with environment, "dryness!" could be the kind of exclamation, or "you really inked that one" for a huge mistake or failure, or if they change colour like some octopii "taupe!" for cases where an ancestor might have changed to a certain colour to avoid a predator. [Answer] The worst criticism I think is saying someone is evil, that is, someone that wants to harm or benefit from others. [Answer] Things that stink. Things that imply harm. Consider the British "bloody". Nothing wrong with blood but something has to have gone badly for anyone to end up bloody (and back before lab techs might break a vial of it things had to have gone quite badly to end up bloody--although it could be to something else. A butcher could be bloody without having suffered misfortune but the cow sure did!) [Answer] You can pick any word as a curse, insult or smear. Just look at Captain Haddock smear words collection. The context makes the insult, not only the meaning. ]

[Question] [ *Disclaimer: The following question is an in-Universe question for a wip project called "The gods of ordinariness"* My friends, I am in a spot of trouble. On my daily drive to work, I have to pass a grand total of 34 traffic lights. This of course entails a lot of waiting around and in my boredom, I tend to make up fantastical stories and characters in my head. Lately, I have been reading up on the mythology of ancient Greece and Rome, and, inspired by their slew of minor gods for all manner of things, I came up with one myself: **Enoia, the ample bosomed goddess of traffic lights** (a pun regarding my annoyance at red lights and the German word for traffic lights, "Ampel") I would say stuff like "Please turn the next light green, Enoia" when approaching an intersection and "Praise be to you Enoia!" and "Why do you hate me Enoia?" respectively depending on if my prayer came true. This was just a lighthearted way to deal with the annoyances of commuting, until today. You see this morning, I overslept. Luckily it wasn't for a very long time, about fifteen minutes, but long enough to make it very likely for me to get to work late and get in trouble with management. As I jumped into my car, I mumbled something along the lines of "Come on Enoia, if I get nothing but green lights on my way, I swear I'll make it up to you somehow." I didn't really mean anything by this, but surely enough, every single traffic light either was green already or jumped straight to green as I approached. In the end, not only did I manage to get to work in time, I actually arrived five minutes early. This has never happened before and statistically, the chance for every single one of these 34 traffic lights to be green must be close to zero percent. Personally, I'd call myself agnostic, but this strange occurrence has got me a little spooked. I don't really believe that there actually was a goddess of traffic lights watching over me, but *what if*? I don't want to incur her wrath by failing to uphold my promise and get nothing but red lights from now on, you know. But on the other hand, I have no clue how I can actually please her. Thankful prayers don't seem to cut it given how hit-and-miss my experience with traffic lights was before. I also don't have a clue about her other than the name I have made up for her and that she has the power to cause traffic lights to change. This leads me to my question: **What would be a good offering to Enoia, the goddess that controls traffic lights and how can I make sure she receives it?** Oh, and human sacrifice is off-limits! [Answer] **Become her champion** and Stand vigilant in the dark places that have yet to see her colored lights. Locate a pedestrian crossing in your area that lacks traffic lights and is notoriously problematic to cross safely. Impersonate the traffic lights using the means bestowed upon us mortals by Enoia herself for this very purpose: [](https://i.stack.imgur.com/F4fDU.jpg) The colder the weather and the denser the smog, the greater your sacrifice to Enoia becomes. (image from [crossing guard](https://en.wikipedia.org/wiki/Crossing_guard) on Wikipedia) [Answer] Believe it or not, many ancient religions have a 'god of the crossroads': Papa Legba in Vodun, Janus in Roman mythology, Hermes in Greek mythology, Saruta-Hiko in Japan. It's an old, old idea, because crossroads are seen as transition points where one can be blocked, or robbed, or lose their way, or discover something or someone new. Your Enoia would just be a modern version of that. Typically one would place a shrine on the corner and offer flowers, food, or trinkets to earn the god's blessing. Or if you want something more proactive, one might maintain the crossroads by painting crosswalks, cleaning the traffic lights, picking up litter... One might even spread Enoia's message more broadly by extending traffic control into new areas: allowing others to pass through doorways first, saying a short prayer to Enoia before turning left in a hallway, making a mystical gesture when a lock is opened or closed.... [Answer] Enoia, like all Gods, expect from their believers **Worship** And to her, there is no greater joy than to see a devot believer respecting the red light, stopping its engine in sign of submission and loyalty to their loved Goddess. [Answer] ## You've already done it By posting here and telling us about Enoia, the ample bosomed goddess of traffic lights, you are spreading her gospel in the fastest way possible. You are also demonstrating the seriousness of your devotion by publishing this incident and showing your own humility and gratitude. Asking for help in determining how to continue expressing your devotion is also a plus, as it demonstrates further humility and gratitude. To that end, the second best thing you can do is set up shrines at the nearest traffic lights. Make sure they reference her by name in big bold letters, so anyone who wants to know more can easily find out about her. Praise be to Enoia, the ample bosomed goddess of traffic lights! [Answer] # Prioritize pedestrians <https://www.cbc.ca/news/canada/montreal/montreal-traffic-lights-pedestrians-1.5363500> > > Montreal Mayor Valérie Plante plans to install pedestrian lights and countdown timers at every set of traffic lights in the city as part of a "paradigm change" that will put pedestrian safety ahead of traffic flow. > > > > > "What is more important: the lives of people or [for traffic] to be more fluid, in a way that it goes faster?" Plante asked Monday. > > > > > "For me, as mayor, the choice is obvious. It will always be security." > > > > > The plan, which Plante said will take five to eight years to complete, will see pedestrian signals installed at all intersections, countdown timers added to all pedestrian signals, and the time available to cross increased to accommodate "the most vulnerable road users," such as children and elderly people. > > > Valérie Plante is clearly a worshiper of Enoia. They seek to build more temples for people to worship Enoia, with the make believe cause of pedestrians and children used to inspire people. Go to your local city hall and argue you need a city with more support for children, the elderly, the disabled. Argue you need more traffic lights to protect the public. You'll need excuses, because few prioritize her worship, but with those excuses you can help support her ascendance to greater godhood and increased worship. [Answer] **Become a priest** Decorate your vehicle with flashing lights. When you draw near switch on the lights. A siren is an optional extra. This will warn other road users of your superior status. You will be allowed passage. [Answer] Install traffic lights in new places. You may also need to add tithe booths to cover your expenses. * Hallway intersections at work or school * Unlighted road intersections * Busy parking lots * Drive thru restaurants or banks * Race tracks (vehicular, pedestrian, or animal) * Park trails * Airport bathrooms * Roller coasters * Car washes [Answer] 1. When in doubt go old fashion. Offer blood, rames are hard to come by so I would advise pigeon blood. 2. Burn cash, this will hurt but all the more to show your gratitude. Eddit 3. After reading the comments I'm convinced that a third offering will be required. Even in modern religions liquids are poured out as a form of offering. I recommend this approach for your 3 offering. As for what liquid alchohol is traditional but give the nature of your goddess I recommend gasoline or some other oil. [Answer] Confront the infidels: If you see people jaywalking, honk your horn. Or admonish them, after all children might see them and take them as their role model (if you are in Germany, you probably know how serious that is). [Answer] Dress yourself in Her colours: red, yellow, green. For a particularly devout outfit, make sure it's a red hat, yellow shirt, green pants. You can also paint your hands orange if you're going to be doing any ceremonies. ]

[Question] [ I am currently working on a setting which is fantasy but based around a soft approach to speculative biology. It is a tidally locked world with the habitable region based around the terminator between the bright hot sun side and the freezing dark, filled with terran descended flora/fauna. The main continent is bisected by a long range of extremely tall volcanic mountains. The south, where sunlight is more plentiful, is relatively similar to terran plant life. But the north, where it goes from twilight to darkness, is where things become much more alien. One of the ecosystems I want to use are forests of fungal plants in place of trees, located near the ocean in a vague analogue to Europe. My biology isn't the best but I know fungi feed off dead matter. My question **isn't** if it could work, but rather **how** it could work. I was thinking an underground system of dead matter running off into the ocean that the fungi reach down to consume. Also possible there are lots of megafauna which migrate across the continent to pass away in these area, feeding the forest as they decompose. This setting is fantasy so 100% plausibility isn't necessary (think Dougal Dixon or Flight of Dragons). [Answer] Before vascular land plants, there were weird fungal “trees.” People still do not really understand what exactly they were or what they ate. They were called **prototaxites**. [](https://i.stack.imgur.com/3h5oQ.jpg) from [pinimg.com](https://i.pinimg.com/736x/7c/7a/94/7c7a94a93926de9765bc246ffdd9f937--paleo-flora.jpg) [Wikpedia: Prototaxites](https://en.wikipedia.org/wiki/Prototaxites) > > Prototaxites is a genus of terrestrial fossil > organisms dating from the Late Silurian until the Late Devonian > periods, approximately 420 to 370 million years ago. Prototaxites > formed large trunk-like structures up to 1 metre (3 ft) wide, reaching > 8 metres (26 ft) in height, made up of interwoven tubes around 50 > micrometres (0.0020 in) in diameter. Whilst traditionally very > difficult to assign to an extant group of organisms, current opinion > suggests a fungal placement for the genus. Recent discovery of what > are likely algal symbionts makes it a lichen, rather than a fungus in > the strict sense. > > > from [livescience.com: Prehistoric Mystery Organism a Humongous Fungus](https://www.livescience.com/1461-prehistoric-mystery-organism-humongous-fungus.html) > > On the inside, Prototaxites is clearly not a plant, composed as it is > of interwoven tubes just five to 50 microns across (50 microns is > about half the width of a human hair). “With that anatomy, it > suggests lichens, fungi or algae,” Boyce told LiveScience. > > > I like the idea that a lot of dead junk had built up for a fungus to eat. Certainly a lot of dead junk did build up, as evidenced by the huge coal deposits laid down during these eras. But why would a fungus need to be so freaking tall? Mysteries, mysteries. In any case: your fungal forest. --- [Image: Prototaxite bland fungi](http://1.bp.blogspot.com/-1hX_PL3d7mM/Vekwnlw0nqI/AAAAAAAAASY/oFIRo7IQ0Kw/s1600/Prototaxite%2Bland%2Bfungi.jpg) this image is beautiful. Not exactly a forest, but prototaxites, eurypterids and an amazing vibe. [Answer] Trees are tall because they are competing for sunlight. A fungus that received all the nutrients it need at or below ground level would have very little reason to grow taller. But you want a forrest of fungi which requires tall branching structures. Fortunately there is a solution that fits your world and also solves the food source problem. Filter feeding. A tidally locked world is going to have massive continuous weather systems these storms would justifiably pick up vast quantities of organic matter, your fungi forrest could be situated at an eddy in this storm where the organic matter collects and settles back to the ground. There would be evolutionary pressure to catch this falling detritus first leading to tall branching canopies of fungi. [Answer] Think of [lichens](https://en.wikipedia.org/wiki/Lichen). Lichens are a symbiotic form of life, fungi and algae. Trees grow high to reach the sunlight. Fungi don't need that. But algae does. Lichens today are rather small, growing on trees, great rocks or walls. But if there are no trees or walls, they have an evolutionary reason to grow up like plants or trees. Algae don't grow large or form hard structures, but fungi can, if they need to. The lichen can grow high as a fungi to support its algae with sunlight. Lichens can form great and fantastic structures, quite well fitting in a fantasy world. The fungi supports the algae with water from the deep, the algae support the fungi with sugar from photosynthesis. You would not need dead waste as a food source, but you can do that additionally. Dead waste (from elsewhere or from dead or ill lichens, too) would rather be eaten by normal fungi instead of lichens. They would add another bizarre componente in this "wood". [](https://i.stack.imgur.com/XK51C.jpg) (Picture taken from <https://de.wikipedia.org/wiki/Flechte>) I am thinking about a plausible reason why there could be a region where normal trees and plants can hardly survive, but lichens and fungi can. Maybe some sort of disease affecting normal plants, but algae are protected by the fungi. Maybe more plausible is an ozone hole depressing regular plants, but surviveable by lichens. That could add some story elements as the region would have dangerous UV light for people during the day. At night, [lichens and fungi could spend some surreal bioluminescent glowing light](https://www.google.de/search?q=bioluminescent%20lichen&client=firefox-b&dcr=0&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjY1ZiIhPXWAhWIKMAKHenQDeUQsAQIPQ&biw=1871&bih=891). [](https://i.stack.imgur.com/YeirJ.jpg) (Picture taken from <https://en.wikipedia.org/wiki/List_of_bioluminescent_fungus_species>) [Answer] One thought that comes to mind is this: imagine that the planet isn't quite fully tidally locked but instead rotates very slowly.\* Therefore on one side of the planet the Sun is always setting, but so slowly it hardly moves over a human lifetime, and on the other side it's rising. On the setting side there are (or once were) lush forests of normal Earth-like trees. Eventually the Sun goes down and those trees are cast into darkness, which kills them due to lack of photosynthesis --- but before they can fully decay they become encased in ice, where they remain for (let's say) hundreds of thousands of years as they pass around the dark side of the planet. Your civilisation lives on the opposite side of the planet, where the Sun is rising. Those dead trees, encased in ice for thousands of years, are now nearing the sunlit side once again. It's still dark where they are, but warm air currents from the sunlit side have begun to melt the ice. Thus, the ground is covered in freshly uncovered and well-preserved dead plant matter, the perfect environment for fungi to grow. It's cold, so they grow slowly. (Otherwise they would just use it all up too quickly to reach any appreciable size.) Since there is always new dead forest emerging from the ice the ecosystem is stable and many species, including the giant mushrooms, have evolved to fit this unusual niche. \*Full disclosure: this might not matter if you're not worried about 100% plausibility, and I'm not 100% sure about the following anyway, but this situation might be quite difficult to achieve from an orbital mechanics point of view. When a planet becomes tidally locked it probably doesn't just rotate more and more slowly but instead starts rocking from side to side like a pendulum until it comes to a stop. However, it might be possible to achieve a very slowly rotating planet if it's influenced by the gravity of another body, such as a small or distant moon, or a second sun/brown dwarf/black hole etc. [Answer] Since fungi are not autotrophs, you need a food source. Maybe the forest is at a crucial pass and massive armies regularly battle over the spot. Thousands of casualties every month give food to the 'forest'. A passerby will see countless bodies with fungal tendrils growing into them. Old armor is half buried amidst the floor. Your fungi might even trap animals passing through the area to digest them as well, making the place hazardous to traverse alone. Second possibility. You have a city whose waste is managed by a small fungal forest. The sewage flows out of the city to a nearby bog and piles up there. Fungi of increasing heights have begun to grow among this bog, decomposing the refuse. [Answer] **Yes a "fungal forest" is very possible.** In fact, it is believed to have happen on Earth in the [distant past](https://www.smithsonianmag.com/smart-news/long-before-trees-overtook-the-land-earth-was-covered-by-giant-mushrooms-13709647/). Before trees evolved there was grasses and among them large fungus. Some over 20ft high. As to what they feed on, well, I think you are on the right path with fauna, mega or otherwise. There would also be spots with vegetation, bushes on higher ground. The leaves falling from them to the lower land can also provide a little "food". It is all very possible. [Answer] The reason fungi on our world use respiration to decompose detritus (and consume oxygen) is because of the endosymbiosis of the ancestor of mitochondria. The reason for respiration among all eukarya, is down to the mitochondrion, which we all share. That ancestral bacterium dictated the use of oxygen. This made the algae and plants happy, because now their waste (oxygen) does not build up. Your solution is simple. Create a different organelle, a different endosymbiotic event. You already have a different planet. If the event endosymbiosed a bacterium that uses nitrate instead of O2, or sulphate, etc. for its respiration, then the substrate can be different too. In particular, if the original endosymbiotic event included a bacterium that uses fluorine for respiration instead of oxygen, (this has other problems but is an interesting exercise) then metabolism of additional carbon sources (including CO2) becomes possible. [Answer] Fungi need detritus to consume, hece you have them - on earth - as a part of forest ecosystems. Some fungi are specialised in organic matter that few other beings can decompose, like wood. [Some even make peroxide](https://en.wikipedia.org/wiki/Wood-decay_fungus), a powerful bleach! So your question turns IMO into "How can I have a steady supply of organic material into an are where little other life survives. The answers of [Vincent](https://worldbuilding.stackexchange.com/a/95014/578) and [Nathaniel](https://worldbuilding.stackexchange.com/a/95025/578) go into that direction. Here's my proposal: On a tidally locked planet, we'd expect a lot evaporation on the sunny side and lots of precipitation on the dark side. So most rivers will flow from dark to light. Now, if a river somehow accumulates lots of organic matter and is then - through a trick of geography - forced to meander into the twilight or dark zone, you could have your fungal biome. Plants won't thrive due to lack of light, but funghi could tap into the organic reach stream. If you want the fungi biome to look like a forest, have the stream underground, slowly seeping through a thick layerof gravel. The ground will be thick with mycelium, while the fungi push their fruiting bodies ever higher. Now, we need a source of organic matter that's steady over a few millenia. I suggest that our river, before meandering back into the dark, flows through a sunny part of your world and gathers lots of plant matter. Maybe your fungi biome grows on the outflow of a large moor. For this convenient flow pattern, we need a sicle shaped mountain range, paralell to the terminator (day-night line) with the belly pointing towards the sunny sides an the points to dark side. This will serve as a watershed our river has to flow around. Maybe there's the rim of a huge crater that was broken at a few convenient places? Or during an iceage, the glaciers on the dark side pushe a lot of ground towards the sunny side, creating a system of [end moraines](https://en.wikipedia.org/wiki/Terminal_moraine) that now constricts flow. Incidentally, the [Münchner Schotterebene](https://de.wikipedia.org/wiki/M%C3%BCnchner_Schotterebene) is a bed of gravel that was pushed off the alps over several glacials, in some parts the groundwater table is 40m below the surface. So there is a precedent for low groundwater table near heavily glaciated areas! It gets better: the ground level falls to the north, away from the alps and the wholething finishes into a series of end morains, also there are a few moors in the north. The basic layout you need is not totally implausible! [Answer] You could have the a filter web made of, giant, [Hyphae](https://en.wikipedia.org/wiki/Hypha), basically a fungal root system covering the outlet of a stream or an ocean inlet, downstream from an elephant or whale [graveyard](https://en.wikipedia.org/wiki/Elephants%27_graveyard). The hyphae feed on the effluvia flushed from the graveyard with every rain or tide and take up nutrients to feed the fruiting bodies that break above high-tie mark. The resemblance to a deep forest could be quite marked, with the hyphae forming trunk analogues festooned with seaweed and other detritus like the lichens seen in many forest and [swamp](https://en.wikipedia.org/wiki/Swamp) [biomes](https://en.wikipedia.org/wiki/Biome). As an inter-tidal environment the fungi could mesh relatively smoothly with land bound forest or mangrove swamp inviting the unwary to stumble into range of the incoming tide without ever realising their danger. From above you would see a canopy of mushroom/toadstool fruiting bodies extended up into the wind to spread spores to other feeding grounds wherever the wind blows. [Answer] When the dinosaurs died, many forests could have perished for 15 - 20 years in a row, so there would have been many tons of forests which had lots of mushrooms, millions of flies and beetles feeding of the giant dead animals for 10 years, lots of squirrels and other animals feeding from funghi and beetles. If you had a forest that had a dark period every 2-3 years when one of the moons eclipses the sun or a super volcano erupted regularly, there could be forests that have major diebacks every few years and that become mushroom worlds for 1-2 years at a time, until the warmth and sun re-appears. any kind of cool cataclismic event that darkens the skies and provides lots of biomass would make mushroom forests. any carbon rich source for example tar and oil volcanoes could cause giant mushrooms to have an advantage over trees. perhaps tsunamis wash away the forests every N years and make a mountain of wood someplace. mushrooms don't generate cellulose that's why they are not big. [Answer] How about if there were subterranean bodies of water supporting ecosystems of chemosynthetic life. The fungi could be growing down into these bodies of nutrient rich water or their outflows. Perhaps variations in the ecosystems would also cause variations in the fungi that grow or how they grow, thus giving regional variation to the "forest"? ]

[Question] [ Imagine a world with many gods that have been in constant battle with each other. However, the gods are *exactly* equal in strength, the very nature of godhood enforces a sort of balance in their strength, meaning neither side has been able to defeat the other. The gods have been in a stalemate for a *very* long time. This war is not just metaphysical. Actual physical entities exist, roughly equivalent to your demons and angels (though the gods are not divided by a clear good or evil division that would imply). These entities were originally created by their respective gods and are innately predisposed to following that gods demands, with the more powerful able to move between spiritual and physical planes. The gods themselves also have a physical body that represents a portion of their strength and could in theory die if overwhelmed by enough angels/demons, though they are drastically stronger then your average demon. War has been fought using these entities and by the gods themselves on both physical and metaphysical planes. Then humans appeared on earth, which is a very recent development compared to the long life of gods. Humans were not (directly) created by any specific god, indirectly human evolution was made possible by the power of the gods being so abundant that humans soaked up a small portion of the power. This was not an intentional action by the gods. As a side effect of how humanity came about they are the first sapient creature that is not bound to any specific god's source of power. They are not forced by their very nature to side with one god or another, and have free reign to pick who they ally with. This makes them an outlier, and a possible [kingmaker](http://tvtropes.org/pmwiki/pmwiki.php/Main/KingmakerScenario). If the majority of humanity sided with one set of gods their extra strength would be enough to give the gods an edge in the battle, breaking the tie and allowing one side to finally defeat the other. The gods are now spending much of their time trying to court humanity, to draw humans to their side in hopes of tilting the balance in their favor. They still war, but the warring has slowed some as they focus on gaining allies within humanity. My main question is: How can humans be a believable deciding factor in the gods war while still being appropriately limited in strength? That is to say most humans are tiny and pathetic compared to the power of a God. A trained human may be able to deal with the weakest of the gods' followers (think imps and the like), but most humans wouldn't stand a chance against your average demon, and gods have a *vast* number of followers. Some humans, the greatest of them, will grow to be strong enough to defeat demons, but few will grow strong enough to defeat even a moderate strength demon in battle. Even the rare few humans able to take on the stronger demons are still tiny in numbers compared to how many of these demons gods already command, making them seem minor compared to existing gods' strength. Many humans never take sides in the war, and of those that do take sides many end up on opposite sides, counteracting each other. The final result seems to be that humanity is a minor resource compared to that which already follows the gods, making one wonder if the energy spent courting humanity is worth the minor extra strength they offer. Thus I'm trying to figure out how to better explain why gods care enough to be trying so hard to court humanity; and generally how to make the heroes of such a world have more impact. Gods *do not* gain power through belief or worship; they want humans to fight directly in the war not be some metaphysical battery pack. Gods can bestow power on humans, which is efficient enough to be worth doing, but I need humans who are not gifted power from a god to be at least close to the strength of those that are, meaning that there is an effective cap on how much strength humans gain from the gods, and it's not enough to make them unstoppable war machines by itself. This is your general sword & sorcery kind of story, so the classic roughly-medieval technology level for humans should be assumed. Magic exists, independent of gods' power, but it has upper bounds on its strength as well. What else can be done to increase the importance of humans in the gods' war? [Answer] Gods think in time ranges normal humans can not even comprehend. Even if one god has only a few humans more on his side one of these humans might be able to defeat a single follower of an enemy god. This single follower might have an impact on a later battle, which in turn has an effect on other battles... As gods are exactly equal in strength every difference can be felt by them in the long run. And I am talking about what these gods would define as "the long run". This is basically the butterfly effect. Gods don't directly care about humans - they care about the slightest difference in power these humans might create. Furthermore the gods may not know how powerful humans may become later. Again, gods are thinking about time ranges humans cannot even comprehend and these humans are not directly influenced by the gods. They can't know what weapons they might develop, what strategies they might develop, what other species might one day sprout from the remains of these humans. If you were exactly as powerful as your opponent and there was no direct way of winning you would choose to rely on this unpredictable factor. After all you have a long time to wait for an opportunity and a long time to shape them in a way that no other god does. Uncertainty is the key here. And uncertainty is also why you want them to be on your side. If they view you as the one mighty god above all of them they won't kill you, but your enemies. If they appear to be a threat one day it's far better to control them and maybe change the direction they are heading again to make sure that you will forever stay in control. This is also a fun way to spend your eternity. Uncertainty is the best thing that can happen to an immortal creature to kill some time. You could also turn the war into a tournament - let your humans fight the humans of the other gods after a few centuries. See whether your tactics were better or the tactics from the other gods. Spending eternity alone without anything happening is dull - uncertain events and a task to perform is important. Even gods need goals. For an eternity. [Answer] The gods are evenly matched. Not only are the gods evenly matched, but everything over which they have direct power, which are essentially their creations, angels and demons, are also evenly matched. What conflict there is is stagnant. Due to the nature of godhood, and partly because every god considers that it should be unthinkable anyway, the idea of a direct attack upon a god by anyone is unthinkable. Gods have enforced this upon themselves and upon all over which they have control. Those humans are a bit worrying though - they are small, weak, very mortal, but they think too much for anything to be unthinkable. Gods are a little afraid of humans - not because they are considered much of a threat, but because they are not subject to control, and are unpredictable. That is exciting for a god. With a stalemate in the arenas over which they have direct control, exactly because all gods have direct and equal control, the conflict moves to other arenas where influence is limited, indirect, or sometimes not present at all. It starts as spectatorship, watching as human battles are fought, as intrigues are laid, as plots are foiled. Gods start taking sides - not by exerting their powers, because so far that has been ineffectual anyway, and because this is more for relaxation, for entertainment. Instead the affairs of humans become like television soaps to the gods. Then gods start supporting groups, individuals, countries like humans support football teams, but passively, at first, though they can see that vicariously through human activity they can gain small, but satisfying victories over other gods supporting other humans. And then gods start actively interfering. They just can't help themselves. That's what gods do. That is why gods court humanity. To a certain extent they have already decided who they want to support, and why, but victory over another god is so much sweeter if the winning team show their support for their biggest (literally) fan - prayers before a battle, a mention in a war-cry, all music to a god's ears, especially if another god can hear. Gods sure as hell like rubbing another gods nose in defeat, even if it is only symbolic, and on someone else's battlefield. The symbolic victories become the only victories possible - therefore the human arena becomes the battleground for the gods, because inequality becomes possible. Of course, the gods cannot stop interfering - which is their mistake, really, because the humans start thinking... [Answer] Gods are not all-knowing. Sometimes, a minor threat can seem more significant if we have uncertainty about it. You, the author, know that there is no plausible scenario under which a human could threaten a god, but do THEY know that? If god A sees god B actively courting humanity, there just might be this tiny seed of doubt...maybe god B is up to something. Maybe he knows something I don't know. Everything else is in balance, there's no other avenue for me to pursue that isn't equally likely to end badly for me, and god B is putting time and effort into this, so I'd probably better get involved as well, just in case. Humanity may never actually make a difference, but as long as they're perceived as a potential factor, there will still be effort poured into trying to grab the only real wildcard up for grabs. [Answer] When in doubt about the need for a particular hero in a mythological event, you can always use a prophecy. In particular, in ancient Greek mythology there was *a mortal who was a deciding factor in a war between immortals*... ## The Gigantomachy When the Titan [Cronus](https://en.wikipedia.org/wiki/Cronus) castrated his father [Uranus](https://en.wikipedia.org/wiki/Uranus_(mythology)), the Sky, with the sickle fashioned by his mother [Gaia](https://en.wikipedia.org/wiki/Gaia_(mythology)), the Earth, a few drops of blood fell on the ground and fertilized it; and from the fertilized earth grew the [Giants](https://en.wikipedia.org/wiki/Giants_(Greek_mythology)). As sons of the Sky and the Earth, the Giants were immortals (with conditions), and they soon challenged the supremacy of the third-generation gods, the [Olympians](https://en.wikipedia.org/wiki/Twelve_Olympians). (Note that in this context "Giant" is simply the name of this particular race of immortals. They were not necessarily of a large size. The word changed its meaning in the late antiquity because it was used in the Greek and Latin translations of the Bible "to refer to men of extraordinary stature and strength"; so says the OED.) The following summary is abstracted from Wikipedia, where links to additional reading material can be found. For another summary see "[Hercules and the Giants](http://www.perseus.tufts.edu/Herakles/giants.html)" at Persesus; this one has a picture of Hercules sneaking up on the giant Alcyoneus. The war between the Olympian gods and the Giants is known as the Gigantomachy, which is literally the "war of the Giants" in Greek. The direct cause of the war may have been the rape of [Hera](https://en.wikipedia.org/wiki/Hera) by the giant Eurymedon, or the theft of the cattle of [Helios](https://en.wikipedia.org/wiki/Helios) the Sun god by the giant Alcyoneus, or the very nature of the Giants as children conceived by the Earth when she was angry; mythographers are not in agreeement. [Apollodorus the Mythographer](https://en.wikipedia.org/wiki/Bibliotheca_(Pseudo-Apollodorus)) says that there was an ancient prophecy that the Olympian Gods could defeat the Giants only with the help of a mortal; and for this purpose [Zeus](https://en.wikipedia.org/wiki/Zeus) the supreme Olympian God summoned [Heracles](https://en.wikipedia.org/wiki/Heracles), whom the Romans called Hercules, his own bastard son with the mortal woman [Alcmene](https://en.wikipedia.org/wiki/Alcmene). Long story short, Heracles did his part, killing the giants Alcyoneus (using the knowledge [Athena](https://en.wikipedia.org/wiki/Athena) had about the conditions attached to the immortality of the Giants) and Porphyrion (with the help of a thunderbolt of Zeus). The Olympian gods won, which is not a spoiler because it was of course known from the beginning of the story given that they ruled the classical world.  [Heracles (on his feet) fighting the giant Alcyoneus. Attic black-figured cup, ca. 520 BCE. Picture [available on Wikimedia](https://commons.wikimedia.org/wiki/File:Herakles_Alkyoneus_Cdm_Paris_322.jpg), by Bibi Saint-Pol, in the public domain.] For his help in the Gigantomachy and for other contributions Hercules was eventually made immortal and took his place in Olympus; this clearly beats the Medal of Honor, the Victoria Cross and the Légion d'honneur. [Answer] Gods and their coorts are extremely powerful, but they radiate a God-essence of a specific "kind", easily felt by other Gods and their underlings, especially if they are of a different "kind". Something akin to a cosmic smell likening all participants to a "faction" and making them very recognizable. This means surprise attacks and behind-the-lines spying is not possible; Battles are always in open field, with bombastic provocations, duels and all associated folklore. Humans do not radiate any specific "smell" so they can be used for stealthy tasks where physical strength is not all-important, but cleverness is. ## Clarification: The general idea this God-essence "smell" is pretty much impossible to ignore, at least if it's not the same you are radiating. As a specific twist you can assume humans can feel it, but, not belonging to any God-essence, do not radiate any. Gods and their underlings *can* use deception, but they are not able to use stealth (at least if someone is "reasonably near" to them). The effect is similar to having each divine creature constantly radiating unstoppable (neutrino-like) particles (intensity decreasing with inverse square of distance) and living creatures can feel this flux; if very far (flux is low) you have to "look" to "see" it, but if source is near and powerful you just can't ignore it. Humans stealth may be useful in many ways and details depend on plot. A short example list includes: reckoning, sabotage, intelligence, assassination and messaging. [Answer] Humans are poker chips. The god with the most humans at the end of the game wins. There can be a few scenarios that can bring this about: 1. The gods are bored and need something to do. They created a planet to play Dungeons and Dragons. **We** would if we could. 2. The gods are in a MAD situation (Mutually Assured Destruction) and need to fight proxy battles so they don't start something suicidal (US & USSR). 3. The gods are in power stalemate. One changes the world to its liking and another changes it back to the way they like it (repeat approaching infinity). So, they decide on a set of rules. [Answer] I can think of a number of things, but only one is actually interesting to me: humans are more than they appear, but they don't realize it. As you already said, angels and demon are bound to metaphysical rules that do not apply to humans. With knowledge of those metaphysical rules, humans stand to exploit weaknesses in angels and demons that those angels can't exploit in themselves. Likewise, gods also have metaphysical rules, but on a much more complicated scale. In all great battles, the priest has a power that can cut sharper than any sword. This is a common story trope. The "action" hero is highly praised and idolized at first, but as the story goes on, you learn that his power is great, but cannot compare to the ultimate power of the priest. And preparation for each is proportional to their power. The priest spends hundreds of more hours studying and praying than the hero does practicing and sparing. And each can also only fight under the right circumstances, but the priest's is more versatile. The major difference is that once proficient, the hero ultimately ages into obscurity and weakness while the priest gets stronger and stronger with every decade he lives. Some common elements in such stories include: * Free will is what makes humans different and ultimately the decider in every god's fate. * Knowing the true name of a demon or god gives you power over it. * Speaking the tongue of a demon will give you special attention from that demon (i.e. he will listen at least). * The celestial bodies hold a power of their own that can be utilized. * Meditative power can move real objects. * "Holiness" can grant you and your allies a god's favor. * An ancient knowledge known only by your cult has a strong power. * Magic is an extension of this priestly power, as evidenced by spells. * Prophecy, either known by the cult, or special revelation to a character. * Knowledge and use of powerful holy relics that connect the human realm with the other realms. All of these can be used to make a compelling story that makes the readers contemplate the power of the mind over the sword. They make a story that shows humans can matter in such grand-scale things. But if you just want a slasher (like the movie *Immortals*), I don't know what would be convincing that humans can actually matter in this war, and I don't think your readers would care, as the fans of *Immortals* didn't seem to mind. [Answer] The Gods have been locked in their stalemate for eons; the timeframe of the arrival of humanity is "a recent development". Currently, your average human loses to a demon but can maybe beat an imp. However, the Gods are used to operating on very large timeframes assuming little change. Human invention may rapidly outstrip the Gods abiilities to react and counter; for example, perhaps a Roman Centurion in 120 AD, armed with a spear, is outclassed by a demon, but a modern US Marine may be able to defeat several demons with his assault rifle. The longer human development is allowed to continue, the more relatively powerful humanity gets with respect to the Gods' other followers, by virtue of the human tendency towards scientific and militaristic progress. [Answer] ## Shortcut to awesome This is going to make some assumptions, so bear with me. You mention that the stronger of the gods' minions are able to manifest themselves in the physical world. I would take that to mean that there is something about physicality that is difficult to achieve, and also desirable. Maybe it is like pushing through a metaphysical barrier and the weaker angels and demons simply don't have enough juice in them to accomplish this. That is, until someone realizes that humans can act as a shortcut through the metaphysical barrier. Maybe instead of having the breach through all of reality, weaker angels and demons can simply posses a human, which requires much less effort. The possessed human acts as a kind of meat suit that the godly being could use to interact with the physical realm, maybe even allowing them to channel some/all of their powers. ## Boots on the ground The current metaphysical chessboard is at a stalemate. The gods are all balanced in power, and clearly their minions are as well. But once you have humanity enable more of the divine beings to enter the physical plane, you start shifting that power. Each human that can be possessed and turned into an avatar essentially acts as an upgrade for one of the lesser angels/demons since they can now manifest when previously they couldn't. The more human followers a side has, the stronger their position will potentially be on the physical side of things. ## Analogies for the win Think of the physical and spiritual realms as being two rooms in the great house we call reality. They are separated by a wall. Gods and their stronger minions are able to tear a hole in that wall and travel between the rooms. Now imagine humans as being a door between these two rooms. If the door is locked, then it might be possible to break in still and cross over, but it will require some more effort. If the door is unlocked though then it takes hardly any energy at all to go through it. Losing the metaphor, this means that humans can act as either willing or unwilling hosts. An unwilling host takes more energy to possess and would probably be able to fight back, making it not too much better than the usual way of manifesting. But a willing human host would be like the open door above. Easier to posses means less energy spent manifesting and more energy available to throw around. Therefore it is probably in each god's interest to have as many *devoted* followers as possible simply because it maximizes their weapon potential. [Answer] # Gods are fundamentally and causally evenly matched. The notion is that, the Gods are inherently evenly matched, but humans are exempt from this matching. For example, the action of a god to create a demon, intrinsically creates two demons. One on his side -- the the god actually wants, but also one for his enemy. (If the sides are not so clear cut, then say instead "One who is intrinsically opposed to the first). When a demon kills another demon, it must sacrifice its own life to do so. Direct actions in the war of the gods is futile. It is all about cunning strategies. Such as misdirecting your foe to go to the wrong place, or working out a way to imprison your enemies demons for a few millennia. Bold and direct actions are pointless, as the cosmic balance will simply counter them. However, humans changed all this. Humans are except from the cosmic balance. When a human swears to your side, this does *not* cause one to swear to your enemy. When a human kills a demon, then the demon is dead, but the human still lives. Sure, hundreds of humans died in the attempt, but perhaps the important thing is, for the first time ever, your side now has more demons than your foe. **Humans are the only thing that can permanently change the balance.** When it comes to keeping them alive: yes a demon can slaughter them. Which is why it is generally worth keeping enough demons on hand to counter the enemy demons, giving the human the chance to take down just an extra 2 or 3 (out of dozens) demons than you lost. When it comes to creating human champions, these yes are affected by the cosmic balance. When designating a hero allows the other side to designate a hero also. But here it comes down to strategy and information. Exalting a human into a champion at the right place and the right time to kill an arch-demon, can be far more effective than a champion just leading an army that is on garrison duty. Human champions still count as humans for purposes of the cosmic balance. Which is why the gods can't make them too much stronger than normal humans -- otherwise they tick over into demons and are self-countering. [Answer] ### Numbers and intelligence A single person may be able to defeat a medium-strength demon. But darn, there are a lot of humans. And just by their sheer force of numbers and wit they defeat even the biggest demon. And before you know it, those lots of humans have evolved. Suddenly they're firing strange weapons, explosions, lasers, nukes. (A millennium is like a heart-beat time-wise for a god, right?) In short: humans are very resourceful and there are a lot of them. [Answer] Related to @Secespitus' answer, I did something similar. I had a similar scenario (though less divine and more just two alien races in war so old, no one knows why they are fighting) where they are incredibly ancient and long lived races. One of the values of humans and their short lives are they are increadibly decisive by the alien's standards. The aliens are playing chess while the humans are playing hot potato. It confounds the aliens that humans can move so quickly and both races meddle in Earths affairs trying to harness this ability. In terms of the species, humans have the best endurance of the animal kingdom. In a race over 100 miles in distance, humans win hands down... either they are faster than the animals, or can catch up because of less need of down time. We might not be strong or fast or dangerous on our own, but the longer the fights go the more likely the human is to win... if only cause they will win. Also, we are intelligent and pack oriented. This is a dangerous combo as we are able to recognize patterns, communicate these patterns to others, and use them to outwit animals. Turning their own talents against them with whats avaible. Pack hunting means the group is quite important to us. If you kill my buddy, I will avenge him... but so will someone who I might not care for ordinarily. Our concept of the enemy of my enemy is quite advantageous in that it allows us to suspend our internal-competition for mutual benefit. In the modern age, it's believed that any two people are at most seperated by six individual connections... for each buddy that dies, you mobalize a near pyramide scheme like amount of people ready to avenge that connection... As one of my aliens observed of humanity, "You can fight a human in any possible area and you will always win. But you never fight **a** human. They come in packs. With each human you fell, the pack only grows larger. You will fight them all." In Deep Space 9, we see the alien character Gul Dukat outline his belief in war: It isn't to take territory... it's to show your enemies that they were wrong to oppose you in the first place. Humanity doesn't fight wars (sucessfully) like this. They fight to eliminate the threat. Gul Dukat was fighting a war of Conquest. What he didn't count on was that you can't fight those wars with humans. They fight to end the threats, not to prove they are better than their foe. I would say what the gods who court from humans is a follower that can endure things better than most, puts aside internal conflict when external conflict arises, and can swarm their enemies with superior tactics. A demon or an angel would be better on the one to one scale... but the humans will attack with superior numbers. [Answer] You could try something more morbid depending on how dark you would like your universe to be. Perhaps the interesting factor of humanity is not that humans act independently but instead that they absorbed divine power without any god's desire that they do so. I can see this as a situation where the species continues to absorb divine energy while breeding and reproductively propagating the power that the species has already gathered. The whole species, altogether, is a baby god that is only growing more powerful. If humanity is able to find a way to harness all of its power to act as a unit, they will be able to do powerful things that will only become mightier as time passes. In a far distant future, humanity might not just become a kingmaker but could possibly become king. This means that humanity is a threat that must be dealt with, but it also presents an opportunity. For the first time in history, the presence of divine power in the universe is growing. The creation of the servant creatures did not create new divine power, but the birth of humanity has. Whichever god can figure out how to direct humanity's further growth more into his power will find a new source of strength that he can seize for himself. Thus, the gods are now struggling not just to prevent humanity from becoming a god in itself but also to try to mold its power into a form that it can take. If humanity as a whole (or perhaps significant portion) ever reflects the nature of a given god, he can take those humans' lives into himself and become the most powerful god and finally win. Such a setting would see gods - even ones who might thinking slaughtering main to take their strength as against their nature - taking an active hand in human history. It seems like you could take such a setting in many interesting directions. Maybe the world is almost falling apart because of the gods' maneuvers in the world to direct mankind toward himself. Maybe some gods are simply trying to exterminate mankind so the stalemate does not break. Maybe some gods are observing mankind to see if there is some way THEY can evolve and in effect become more like man instead of the other way around. [Answer] Give the Gods direct links to the Earth. The gods have Bailiwicks, areas of control, which are the source of the Gods Power. If these areas of control are balanced on the planet where the humans are, humans become excellent proxies and should be courted because of this. There are bits that need to work together here. The God of Ice has and the God of Heat are balanced, but the sphere of influence shifts north to South as the year progresses, it is always balanced. the God of Earth is balanced with the God of the Sea. Trees vs Grass, so on and so on and so on. The gods are balanced, but clumsy. Direct Intervention could very well lead to some Mutually Assured Destruction scenarios (thank you @ShadoCat) so in order to fine tune the struggle, you need a way to impact the world, but with finesse and at arms length. This is where Human Proxies come in. Humans are valuable because they can actually impact the world, but do it in slow and subtle ways. Humans can, through slash and burn agriculture, decrease the god of the Forest while elevating the god of the plains. building a Dam can have a massive impact on a river god. there are seemingly infinite ways that humans can impact the earth, and therefore the powers of the gods. Even if they aren't metaphysical batteries, Humans are very important in the battle for more power. [Answer] > > The final result seems to be that humanity is a minor resource compared to that which already follows the gods, barely worth the expenditure of effort required to recruit them. > > > Well, my thought is that you are going to have to have a formula as to power, for example, one normal human is equal in power to a god by .001 or somesuch. **How it begins is like this--gods start out largely ignoring humanity. But one god, perhaps a minor one, begins to heavily recruit humans to destroy some of the lower "that which already follows the gods."** You've established that humans are a match for the lesser demons/imps and such, which follow other gods, so the minor god begins helping humans, perhaps recruiting some charismatic folk to lead in specific areas. And 20 humans with the favor of a god might be a match for a demon. Even if they are powerful numbers are numbers. If the tech level is Medieval, even staving off infection and adequate medical care would be enough to sway a community. So, minor god begins his power play, gains human followers when no one else is doing it. Has those human followers/fanatics kill another god's lesser followers, and used his human cannon fodder to erode the other god's power base. Then, this minor god made the next play, and that was to kill this other god and take his power for himself. **The other gods may have, at that point, realized that humanity could swing things, and just began recruiting followers as a way to balance power.** This god may have established himself worldwide before any of the other gods even noticed, which might have given him an advantage that let him eliminate a lot of the players. The minor upstart god may well have been long eliminated, but it's possible that the other gods learned from this--and they fear what humanity might do. **The real question isn't why humanity might matter, it's why a god or gods might not have decided to eliminate these wild cards altogether.** [Answer] I can think of two potential reasons. Firstly, maybe humans are just more imaginative than the created Champions of the Gods. I can imagine that an angel or demon created to be a great warrior with absolute loyalty would be good at fighting and not much else. Perhaps creating something to be utterly loyal invariably detracts from its ability to think outside the box. If a God were to teach this being a powerful spell, it would use the spell only for its intended purpose. But... gain a human's loyalty by teaching her the same magic, and she might take it home and play with it and possibly come up with modifications and unexpected new applications that would never have occurred to the Champion. Or even to the God itself. The occasional powerful human that can rival a Champion is nice to have, but perhaps the true benefit of the humans is as tinkerers and experimenters. Secondly, Gods and Champions probably have no need to eat. Humans do, which means humans need to understand how and where to hunt and farm for food. With that comes great understanding of terrain, and all the wartime benefits that go with that. A tactically minded human advising an army exactly where to burst out of a forest to overwhelm the enemy's flank, or how best to lure the enemy's chariots into muddy marshes, could be the difference between two evenly matched armies. [Answer] # Some possible ideas. All of these ideas are takes on mythology. They're not meant to be authoritative in any way. Just possible interpretations of said mythology. ## Idea number 1: An interpretation of norse mythology. The ancient Norse Gods created the humans as bioweapons. This has influenced many myths of humans, which is why they beat up monsters, slay giants, etc. Humans are basically really, *really* scary in context of the other creatures in Norse mythology. Trolls may want to prey on humans, but they'll not push their luck and go into a village, because humans would apply guns to the problem until it goes away. Humans on the other hand cannot easily kill these supernatural creatures. They'd need some form of magic to do that. The easy, over-the-counter kind of magic that any elf, nisse, hulder, subterranean, troll, etc. can do in a pinch. In other words, humans are this giant race of not-dangerous people. Unless you give them the weapons they need. Which to them is practically free. Imagine if dogs turned into superkiller robots if you fed them chocolate. And there were massive million strong dog colonies. And all stores stock Chocolate due to the Chocolate amendment. Do you see the ticking time-bomb that humans are? On the other hand, most non-Jotnir seem to live in relative harmony with humans. The forest spirits help humans log so long as they plant new trees. The spirits of nature help hunters so long as the hunters respect the prey, etc. Because humans can push things back into balance if things go awry. Humans are stewards of nature, and have a very integrated role in doing so. Humans are scary, but mostly benign and everyone wants to let sleeping dogs lie. However, the gods are warring, and one of them just bought a chocolate factory... ## Idea number 2: An interpretation of Greek mythology Most humans are weak. Most humans are frail. But sometimes amongst humans are born men who can challenge the greatest of monsters, gods, and titans. Achilles, Heracles, Jason, Odysseus, Perseus, Theseus, Atalanta and Bellerophon, and those are just the ones from Master of Olympus + Poseidon. These heroes are nothing to sneeze at. Another thing to note is that gods are embodiments of things that happen to humans. If you're the god of craftsmen and you control the humans, you can make war more or less go away. Bye, bye Ares. Note that their power is not bound by their power of worship, but by the emotions and experiences of the human soul. (This is also what Warhammer 40 000 does.) ## Idea number 3: Idea based on, but in no way canonical to Christianity. Human souls are noble and worthy. They're also filthy and sinful. If you get a follower you get their souls after they die. Humans who live lives in accordance to you and your pact with humanity will fuel you. This means that the gods who's pacts make humans live good lives, where they prosper and multiply will have the edge. Furthermore, if your rivals *lose* *their* followers, you'll gain relative to them. ## So... In all of these scenarios you'll have humans being worthwhile. Whether humanity is valuable for their souls, for their potential, for the gods being shaped by the human experience, or finally, because giving them a magic weapon turns them into unstoppable murdermachines that will grind up anything you throw at them to a fine fine dust and blow it in your face... There's plenty of possibilities. [Answer] **Demigods ?** Some mythologies - the Greek one and the Christian one - involve gods mating with humans, giving birth to - usually - mortal offspring with special abilities. Maybe your gods could make demigods in order to increase their presence among humans and eventually defend them against other gods demigods. That concept is roughly the basis of the tabletop role playing game [Scion](https://en.wikipedia.org/wiki/Scion_(role-playing_game)) where the gods of several pantheons - the Norses, Greeks, Japanese, Voodoo, etc... - united to fight their ennemies, powerful entities that try to invade the human's world like titans, giants, you name it. The problem is that the gods can't face the threat themselves: * They would cause too much destruction, resulting in more to humans than they would protect them from * They have an agreement preventing them from directly interfering with mortal's business in order to garantee peace and to avoid having some gods dominating the humans. So they came up with another plan: mating with humans to make children that are both gods and humans. They aren't demigods but scion, and can become demigods or even gods if they become powerful enough. Their deitic parent usually appear to them when they become adult to explain the war to them, help them figure out their powers a bit and eventually to offer them some divine gifts - usually weapons. However, the gods-who-can't-intervene trope is pretty common and was even used by Tolkien: since the Valar destroyed and sank a whole continent when they defeated the Numenorean fleet, they decided it was too dangerous to use their powers directly and sent the Istari - like Gandalf and Saruman - to help the mortal races against Sauron instead. [Answer] Here's an idea You said that the human race evolved in part with the help of ambient divine energy. This tells me that each human has a minute spark of power within them. My suggestion is to make a "God of Humans". Not as in having a human turn into a god, but rather a god that has manifested through the collective consciousness and divine power of the human race. Each human is unknowingly and passively contributing to a god's existence via their own, making the Human God an embodiment of humanity. This is a plausible, arguable explanation for the creation of said Human God, and it opens a few doors regarding influences in the war. The first door that this scenario opens is that of a god with variable strength. Rather than being exactly matched to the strength of other gods, the Human God relies on the human population. This is different from using worship as a battery. Rather, think of each human as a cell, helping to constitute a larger being. Therefore, other gods can adjust the strength of the Human God by adjusting the human population. This god can be stronger or weaker than others, turning the tide of battle. The second possibility provided by this god is possession. The Human God has no demons or angels or imps, but can bestow power upon willing humans to form an army at will. Due to the nature of this god, the human army also derives it's strength from the human population. It's like an artificially intelligent mass of energy. Just a suggestion. Let me know if you choose to not use it, as if you don't, I just might [Answer] Perhaps humans are the only intelligent beings capable of designing machines. While a single average human may never take on a demon in a 1on1 fight, she may design ballistas, catapults, explosives and more advanced war machines to level the gap. Further, demons and gods have a crystallized knowledge, which is innate and vast, but static. They either cannot learn or they learn even the simplest notions very slowly. This could be expanded by allowing humans to scientifically explore and analyze the spiritual plane, designing contraptions to bring damage and trap beings across planes of existence. Afterall, that is the true skill of mankind compared to our wannabe predators in the animal kingdom. [Answer] Well, the simple answer is practically stated in your question. Prior to the appearance of humans, the gods were exactly evenly matched. Given that the gods are immortal, it doesn't matter how tiny the advantage humans grant is, if one side has it and the other does not, the side with it will win in the next trillion years or so. It will take long enough that the humans involved might not realise the difference they are making, and almost certainly won't care even if they do. Now, how could you make it a more pressing advantage? Well, you said the war was at least partly physical, and that it's fought by angels/daemons created by the power of the gods. Presumably they use powerful weapons in their fights. So, the question is what portion of the God's power goes to making the equipment, and what portion goes to creating the intelligence and physical accouterments. It would be easy to justify the intelligence being more expensive given the time gap in our own technology between the development of powerful weapons and the development of "smart" weapons. And our "smart" weapons still aren't as smart as a human. So, the first god to stop making angels and start just churning out massive quantities of god-killer weapons and handing them to sympathetic mortals would have gained a big advantage in the physical realm, thus freeing up his power to focus on combat in the spirit realm. The other gods would have had to choose between following suit, or perishing, until finally the physical wars are fought almost entirely by human zealots equipped with personal-size weapons of phenomenal power, and everyone wonders if Angels and Daemons are simply myths since their fighting is confined, by necessity, mostly to the spiritual realm. [Answer] Note: This answer was originally a comment, but since the OP found it interesting and asked me to post it as an answer, I'm going to clarify it a bit more. I think the main point here is: why do you need humans if you have angels and demons (A&D from now on, since I'm lazy)? The first answer that came to my mind is the one found in other works (or videogames, such as Black and White): humans worship you and this gives you power. This answer, however was explicitely forbidden by the OP. So, there should be a way humans are better than A&D and make them more suitable for some tasks. My idea: the A&D are "non renewable" resources. At creation the gods created 1000 A|D each, and now they cannot create them anymore. This is because 1. There is no more "raw material" (Angelium or Demonium) to create more A&D 2. The A&D were not created BY the gods, but WITH the gods (at the same time). At the beginning there was only chaos. Then the chaos divided in and and their henchmen, A&D. So gods have no power to create them 3. (my favourite) New angels or demons are created when an angel and a demon breed together. But since year 0, when the gods started war, they were forbidden to mate again, so no more A&D born since then. This gives some subplots like capturing one of the other entity to use as a "reproductive cow", or some forbidden society of fallen angels and demons which do not obey to the gods, or something more In all these cases, the inability to "produce" more A&D makes disposable pawns like humans very useful, since if you are able to trade 1M humans for one A&D you gain an advantage (let some years pass and you will have 1M humans again, but the other has no way to recover the A&D). Other ways to use this idea is not to prevent A&D creation, but to make it very long or difficult. 1. Maybe the god should "lose" a part of itself to create a A&D the high cost of creating it can be a good push to find alternative ways to have henchmen 2. The creation or growth of a A&D is very long. Maybe you have to incubate the "eggs" for 1000 years, or they reach maturity after a lot of centuries, while humans are much faster (in 15 years they are "ready" for combat). Weak but easy to train. This makes losing them much less of a problem Hope to have given you some ideas to work with ;) [Answer] First of all, as you said, Humans aren't directly linked to the power of a specific god. This means that unlike all of the other minions of gods, they do not need to draw power from them. And since each god is exactly as powerful as the other, having a minion on their side that doesn't draw power from them may just be the edge that they need. They also make excellent workers. Why waste demons who could be on the battlefield to make arms and armor, when a skilled human can make these just as well. Also every army can use some additional cannon fodder. Yes, humans are weak, but we can also be very loyal, and (Stupidly) brave. We may not be the best but by the gods do we try, and we may just provide the distraction that the army needs. (Think in boxing terms, you throw a weaker punch so that your opponent blocks that, opening himself up for a stronger attack right after) And finally, just as Secespitus said, God's think in a much longer term than us mortals, and so who knows how humans may rise in power, and possibly become powerful minions/allies from all the generations born in war? --- EDIT: After all of the new questions on my answer, I Decided to add a few more details to what COULD be the case. Unlike most creatures, humans can do things autonomously. and do way more than dogs for example. Since we are so smart, we can be given commands and trusted to carry out tasks that normally would require a special minion, once again saving power. To answer why humans would want to help: who WOULDN'T want an immensely powerful being on their side. Yes you will be fighting against other all powerful beings, but you have on in your ring, and they can offer you just about anything if you prove your worth, such as an afterlife... (And even if they can't who would call them out on it? The other Gods? Because how do we know they aren't lying about your god's power?) [Answer] Fear.....you stated humans are not bound to either side which means there is always the possibility however remote that humanity maybe at some point unite behind the other side and become the kingmaker . As long as that possibility exists the gods, previously safe by being exactly equal are vulnerable. This new vulnerability/uncertainty terrifies them and explains why the gods are so interested in humanity despite the insignificant nature of the power humanity has. [Answer] I didn't read your full question because you were overthinking things. "How can humans be believable as a kingmaker in a war between gods?" Nukes. Science. Technology. Scifi. Human lategame. That's how humans make a believable kingmaker. Poseidon being a prick? Evaporate all of his oceans and start synthesizing your own water, or maybe just light the tops of his oceans on fire - Byzantium actually figured out how to do that. You gotta remember that humans have a lot of weight to throw around when a bunch of them act together. We're literally making the planet warmer right now. Why not murder Zeus while we're at it? If we can't actually pull that off, maybe we give Zeus a cold. I skimmed the rest of your question. Humans could probably figure out how to hunt demons for fun by using specially made tools. We figured out a way to hunt pretty much everything else we can see. Why not imps and stuff. Consider guerrilla warfare. [Answer] I would question if humans would get involved at all unless they had a self-centred reason to. A bit like 'Pascal's wager', but what if they get on the wrong side? Being able to tip the balance in an even fight would likely result in a massive loss of life/destruction of their civilisation. Think of two evenly matched boxers and a million ants ... yes, the ants might tip the balance, but a lot are getting squashed! My feeling is that the humans would fight if: * they felt that not to pick a particular side would lead to a worse consequence than if they do pick a side * they were pretty sure they could assist in an easy win without much in the way of collateral damage (seems unlikely) * they had some special ability/facility that would effectively allow them to tip the balance without incurring substantial damage (e.g. a hero; a special object; etc.) It is also worth noting that it is not clear that every human would choose the same god (where have we seen that before :-) ). Kind of like ant vs ant in the above example. In most cases wouldn't the human wait it out and see who wins and either fight the weakened god or accept him if he's benevolent? [Answer] 1. I'm sure everybody heard such a sentence as "God is inside of everybody of us". But how do you think, is it correct to say "Everybody of us is inside of God"? 2. Try to use an analogy of microbes - human Earth inhabitants - God. 3. Amount of people means nothing. The quality of group is everything. To continue analogy - there can be millions of microbes in our intestines, but if it is a bad balance - your body starts to ill and feel weak. 4. Who are you - bad or good microbe for Humanity? Or you are God? Or both? [Answer] I know that this is responding to an old post, but if you're still open to ideas it could be that the gods are equal in power until you factor in prayer(or worship/rituals/etc). When humans came on the scene, this new power became available to the gods. The more worship/followers/prayers humans give a god, the more power they can gain. You can weight it any way you want, but it gives reasons for the gods to grant benefits to humans, and humans to curry favor with the gods. [Answer] **Humans that ally themselves with a particular god actually provide that god with the energy of their will-to-fight/aggressiveness, making that god slightly stronger**. While a god without followers is still a god, a god becomes increasingly stronger the more followers, that fight for him, he gains. The more aggressiveness/will-to-fight a human harbors, the stronger it will make the god he fights for. It's only logical that gods will try to convince or *force* (fear?) humans to fight with fervor for them by the millions, to exponentially increase their powers. One could go so far and say that this concept is real. Athletes are influenced by a cheering crowd, why wouldn't a god? [Answer] Some communities, in real life, hold the belief, often considered apocryphal, that - I try to use your language here, even if it may be considered "disrespectful" by some - "some gods" made a deal that is fulfilled by maintaining or derelicting humanity - or, according to your wording, using some sense of virtual balance, "win them over" - over an unspecified period of time (whether it be physical or virtual). **Taking it as granted, it is not the power of humanity, if any, but their (the "gods'") agreement and the outcome of that is binding and may have dire consequences for them. That would totally address the part of your question (to me, the essence), that is, "why gods care enough to be trying so hard to court humanity", if they have to win their own bet in which humans are the players.** ]

[Question] [ The title fairly well sums up the question. We all know elves have pointed ears. Whether they be LotR style with slight tapers, or full blown foot long impracticalities, all elves have pointed ears. In a realistic context though, would there be any advantage to having pointed ears (foot long or otherwise)? While I'm no ear-expert, it seems to me that there would be zero differences between a pointed ear and a rounded one. **Would there be benefits to pointed ears?** --- Please note that this is a [science-based](/questions/tagged/science-based "show questions tagged 'science-based'") and [biology](/questions/tagged/biology "show questions tagged 'biology'") question. It's not about speculation on what pointed ears could be used for; it's about what advantages - specifically in the field of hearing - pointed ears could give to their owners. [Answer] I cannot answer for pointed ears specifically, but the shape of ears is known, in audio science, to have an impact on sounds reflected into the ear canal. See [here,](https://en.wikipedia.org/wiki/Auricle_(anatomy)) an excerpt is below (The pinna is the outer part of the ear; plural is pinnae): > > In animals the function of the pinna is to collect sound, and perform spectral transformations to incoming sounds which enable the process of vertical localization to take place.[2] It collects sound by acting as a funnel, amplifying the sound and directing it to the auditory canal. While reflecting from the pinna, sound also goes through a filtering process, as well as frequency dependent amplitude modulation which adds directional information to the sound (see sound localization, vertical sound localization, head-related transfer function, pinna notch). In various species, the pinna can also signal mood and radiate heat. > > > In humans at least (because it is easier for us to tell researchers what we are hearing) if the outer folds, bumps and valleys of our pinnae are filled with wax, even if no wax is used close to the ear canal, we lose the ability to locate the source of sounds. These folds, bumps and valleys are unique to each person, but when simulated on a computer they create micro-echoes and amplifications that are dependent upon the location of sounds; and the hypothesis is that our brains learn to interpret these in order to give us a sense of sound source position. Thus, the pointing of the elven ears, whether movable or not, may be useful to them in triangulating sound sources; perhaps higher or lower frequency sounds than in the human range. Many animals with pointed ears ***do*** hear frequencies well above the human range. The point of the pointing (ha!) may also just be the physical length afforded; when it comes to sound waves this scale of difference can matter: It is why our bass speakers [and bass musical instruments] have to be larger than other speakers [and musical instruments], for example. The point may act as a wave guide for high frequencies that amplifies them in the elven ear canal. [Answer] One possible 'advantage' for features with non-obvious use in biology is always [sexual selection](https://en.wikipedia.org/wiki/Sexual_selection#Toolkit_of_natural_selection): Bascially at some point in the evoltuion elves with pointier ears were more succesfull in mating and that's why now all elves have pointy ears (the sexual selection effect also doesn't have to stay, so for 'modern' elves it might not really be important). [Answer] Personally, I like Nicolai's answer: pointed ears show good elf breeding stock, so I upvoted. But another couple of possibilities: 1. Pointed ears are more sensitive to moving air and temperature at the tips, although I do not know why this might be useful, but perhaps they can sense impending changes in the weather. 2. They clearly identify an elf. This can have all manner of advantages (and one or two disadvantages), but if being recognised as an elf, on balance, makes an attack less likely then there is a clear case for evolution to start favouring pointed ears. I can see no significant benefit gained in hearing. [Answer] Pointed ears on terrestrial animals allows for better directional hearing; but those ears are generally located higher on the head and have some mobility (see foxes or big cats; they can move their ears about much more than humans can.) What is depicted for elves, or vulcans for that matter, would really have, to my knowledge, almost no difference in function from our own. [Answer] Since pointed ears can expose a higher surface to the environment, they can be used for the heat management of the head, helping cool the blood circulating there. The effect would be bigger for elephant-like ears, but as far as I know elves do not live in the savannah, only in temperate forests, so the external temperature is not so high. [Answer] Apart from the biological and sexual/reproductive uses of pointy ears, there are also some social benefits to consider: * More blingspace. Elves with higher points can sport more piercings, wear more silver danglies and even wear longer engraved [earpoint cuffs](https://img0.etsystatic.com/007/0/5118106/il_fullxfull.404916906_b5a5.jpg). * Elvish architects can stick not just a pencil behind their ears, but also a slide rule, straight edge and a small case of King Aragorn filterless cigs. Finest Shireweed known to Elfkind! * Longer earpoints give Elvish mothers more surface area to pinch when correcting wayward children. * Increased employment opportunities. The long earpoints common to Elves gives welcome opportunities for otherwise unemployable earmuff-knitting Broonies. They love to knit wee snug pointed earmuffs for Elvish families and when treated kindly will churn out a regular supply of beautiful woolen stuffs to last the long winter through. * For the party-poopers, I just did a proper witcrafty experiment. An old pair of leather foot guards served as a handy-dandy stand-in for pointy Elf ears. Put on a Standard Youtube recording of rain and found that the lower limit of audibility for me is level 14. Below that, only occasional loud thunder became audible again. Nifty Elf ears allowed me to hear fairly well down to about level 10 of volume. **Actual Audiological Benefit** = improved hearing of soft forest sounds. Like Ents breathing and wolves scurrying in the distance. Or even the light footfall of a wayward Hobbit. [Answer] And another thing nobody mentioned. PARASITES ! Another important thing in evolution, apart from mating, is not getting infested by some pesky buggers. So maybe the elf suffered a terrible ear-entering-brain-consuming-bug infection and the pointy ears were deforming the ear entrance enough to stop this bug. Or they were just bind to a gene that was needed to hold off some dangerous parasite. Such parasites do exist in our world ( not the brain eating, but bad enough) but I wont give any links. Don't want to spoil your appetite (already spoiled mine :D ) [Answer] They would give no advantage but they also wouldn't cause any significant disadvantage. So, there would be no survival pressure against them if they showed up. If they were considered fashionable, eventually the wealthy and powerful would all have pointed ears. [Answer] in addition to what @Nicolai said, another thing that people forget about evolution is that not everything needs a purpose (or its purpose no longer exists) if something evolves that is neither positive or negative, there is a chance that it will spread for no other reason than it doesn't matter if it exists or not. Think of earlobes, there is no reason for them but there is no disadvantage with them (slight disadvantage of a little energy to create but not enough to influence evolution) evolution is random, the more a trait helps the animal to breed, the more likely it will spread throughout the species. The more a trait stops breeding, the quicker it stops being part of the species. If there is no effect then there is a chance that it will spread, a chance it will die and a chance it will linger with a proportion of the population. [Answer] Pointy and perky ears seem to have an inextricable inverse [relationship](http://www.iflscience.com/plants-and-animals/why-so-many-domesticated-mammals-have-floppy-ears/) with domestication and how well the creature "likes" humans. Dogs, foxes, and other mammals with a stronger fight or flight response tend to have really perky ears while breeds with mellow temperaments have rounder, droopier ears. Researchers are still trying to work out why this relationship exists across species, but haven't reached any conclusions yet. Pointy ears on elves may signify an intrinsic feral nature, naturally easy to spook or provoke. This doesn't mean you can't have refined high elves instead of fighty wood elves, because the culture they are brought up in (and perhaps their long life span) may influence them to tame their instincts. Vulcans in the Star Trek universe are naturally very passionate, and perhaps agressive, yet they [tame](http://memory-alpha.wikia.com/wiki/Kolinahr) their emotions. And, perhaps not coincidentally, they also have pointy ears. [Answer] Evolution is literally throwing a bunch of random updates into a creatures genome and hoping that they'll be better than the last batch. That being said, I can think of several reason's why pointy ears may have been an elven upgrade. 1. It looks good. Remember that blond hair started with one european girl, and it was considered so attractive that there's a significant portion of the earth's population that has blond hair today. Breasts and large butts are also considered to be only evolved do to sex appeal. * It's also worth considering that they evolved for a cultural, non sexual reason. Large ears could have attracted mates because large ears were some kind of social status. Over time they ended up becoming a common trait, even though it may have started as a single prestigious clan or family who were recognized by slightly bigger ears. 2. Listening ability. While the eardrum is more important when considering what you can and can't hear, the ear does hold some importance. If the ears are long, pronounced, or even capable of movement it may indicate that the ears have evolved to locate or pinpoint certain sounds. Perhaps a high frequency elf sound, or certain types of animals that use ultrasonic waves. * If not a device used to capture a particular frequency of sound, a large ear could work as a capturing device for echoes, which are harder to detect with round objects such as trees. * Another way they could function as a sound capturing device is a style which protrudes perpendicular to their line of sight, allowing them to capture only sounds coming from the direction in which they are looking. * If the ears point more upwards, or have a 45° facing away from the ground they could be listening for sounds in trees above them. * If the ears angle slightly backwards to 45°, they may be listening to sounds coming from the sides. I personally would think it cool if their ears were designed to hear the sound of arrows so they could dodge arrows coming from the side. 3. The ears help them communicate. If this is the trope where elves get red ears for embarrassment, raised ears for joy, and drooping ears for disappointment or sadness you can simply relate ease of communication to ease of mating. * It's also possible that they are used to communicate during hunting, espionage, or other times where non verbal communication was necessary.If your hands are full of bow and arrow, this could be quite helpful. This strongly implies that those who couldn't signal were more likely to die off, though. 4. Luck. Some pointy eared guy who lived in the forest with his tribe only survived a bear attack because he was sick the day it happened. He was basically the only guy left so he laid with many women and had many children. Since he contributed a lot of DNA to the gene pool the trait stuck. 5. Sensitive to environmental changes. A good place to put a sensory organ is near the brain, and since the ears were already sticking out, long ears could have evolved to have more surface area and be more sensitive to certain stimuli. These stimuli could include temperature, wind speed, sun strength, or something else. 6. Symbiosis. In some literature elves are known for being able to talk to birds. Now imagine a small bird perched on an elves ear telling it a secret message. Tiny bird perches. (This thought makes me inexplicably happy.) 7. Lazy Genes. Many traits that animals and plants have are basically flavor text of their genes. They don't hurt anything, but they weren't an advantage either. The only reason they stuck around is because there was no need to get rid of them. Doing nothing about a worthless gene is less work then doing something about it. And finally after reading other replies, here are some more answers I didn't think of personally, but did agreed with: 8. Hair. If elves do typically have long hair, having slightly larger ears that stick out may indeed increase their ability to hear past it. 9. Child Raising. Someone made a joke about big ears making it easy for elf moms to discipline children, but in fact this could be true. Cats have a pressure point on their necks that is directly related to the way a mother cat carries its young. I don't know how unlikely this is, but it isn't impossible. 10. An identifier. Elves may have pointy ears so creatures can tell the difference between long lived magic archers and whatever humans are. Whether this is so they can recognize each other or scare off outsiders is up to anyones guess. Or imagination, anyways. [Answer] Pointy ears provide directional cues to other members of the species. You can tell where your cat is listening so, I'll bet, can their kittens and/or hunting partners. These directional dues exist without turning the head. Turning the head provides a larger break in motion camouflage. A dog with pointy ears certainly provides "interest" cues with it's ear pointing - floppy eared dogs do too but it's less clear. So in dogs it's a communication signal. Dogs point with their noses (probably feel sorry for us short pointer humans) but cat's point with their ears. [Answer] Elves' ears are pointed for many reasons that if you pay attention they tell us in the movie "The Lord of the Rings" itself. The two most basic are increased hearing ability (they can hear further, with greater clarity and a wider frequency range) very easy to see in Legolas. And the energetic reading (they "predict" bad presences) that we can see in several elves in almost all the movies. Regarding the capacity it would have in the real world: It basically increases the frequency range and the precision of sound location, in addition to being a vestigial feature that they have not yet lost, it is very likely that they were totally mobile (both things tested by means of the study of animals with this type of ears and similar). If you think about it, for a bow hunter, it is necessary to position the prey very well just because of the sound... sometimes we will have to shoot practically blind. [Answer] It allows the sound collection surface to extend past the hair of creature, should they happen to have long hair. [Answer] Pointed ears are more streamline, less air resistance, and therefore hear "better" when the head is down and moving fast (i.e. less flapping around). Perhaps they used to hunt in the dark, moving quickly, listening for prey. [Answer] Pointed ears are predominantly associated with animals, especially felids, this may be a hint for a possible genetic connection. I do not, however, ever remember even a hint that there would be any benefits related to or arising out of this, however marginal it be. **To the science side of the things, elongated - if not pointy - ears [seem to be associated](http://www.lsu.edu/deafness/HearingRange.html) with hearing into the ultrasound range.** It may however just be the "be different - think different" thing. [Answer] I was born with pointed ears in real life, and within the first year or so my right ear unfolded and looks normal (though there's a small dent at its tip that isn't visible unless you're at just the right angle). My left ear isn't long like the most of ones you see in movies, so there's no hearing benefit. It's likely unrelated, but if anything that ear is *worse.* It's the only ear I've ever gotten an infection in (at least twice), and overall it tends to be a little more clogged, hurt more underwater, etc. I also can't hear particularly high (less than 19kHz, and I'm under 20). My best guess as to *why* my ear is pointy would be that it and the other were folded while in utero. I really can't say what the effect would be if they were genetic, but I hope this can be of help! Also it might be worth noting that the tip of the ear is not broad and flat like pointed ears are in movies and art frequently. This might be better at catching noises than mine, which has a ridge from its point to the normal ridge that exists in almost every ear. [Answer] They allow you to more easily put on a hat that has ear-holes, such as this one. [](https://i.stack.imgur.com/ttXZB.jpg) [Answer] **Streamlining** If the creature swims alot, pointed ears transforms it into a catamaran, highly stable in rough seas. ]

[Question] [ Question inspired by a book I just finished: Dan Brown's *Inferno* Suppose I am a wealthy billionaire who wants to hide from the outside world for a year. Plot twist is, that the world's anti-terrorist organizations think that I might be wanting to use that time to create something very awful, like a doomsday device. And the CIA is right: I am a mad scientist and billionaire, and I need a year of privacy to create my doomsday device (and then release it and... mhahahaha!). While I certainly know how to make money and doomsday devices, I do not know how to stay hidden from the CIA for a year. But I am willing to pay for it. Suppose I can spend 500 million US dollars to be hidden from the CIA. But I do not want to be just hidden. I need to meet *certain people* and make *certain things* and place it in a very specific place (And also create a riddle for Robert Langdon to solve it). It means I will need to travel the world. I will spend money on buying shady things. I will need a laboratory to develop my doom device. I will need to visit highly frequented places, because I will be later on hunted by Robert Langdon, Oxford professor specialized in symbols and symbolics. I want to start working on my doomsday device "tomorrow" (Earth, current technology). Am I able to actually pull it off? [Answer] If you're a billionaire and already under the focus of the TLA Agencies, best how to disappear for a year is... not to disappear. If you'd suddenly disappear from today to tomorrow a dozen of alerts will go of with every single agency, not only from the government. Even more if you're already known as a mad man. So you need a perfectly instructed body double to play your role while you wander of to some frankensteinish castle and build your doomsday device. Since you still make your public appearance no one will come looking for you. Prior to that, you may need to get rid of some family and close friends, since they, as long as not involved in your plan, may blow your cover by revealing details that'll make some TLA Agencies taking a closer look. (Oh myyyy, Pavel is left handed, but yesterday he signed the contract with the right hand). OR: If you're a billionaire just be a good person to others, become the Tony Stark of your world, providing peace and joy and nice tools for everyone at reasonable prices. Build a new cancer research center, invest in new alternative energy projects no one will suspect you plotting evil, when you acquire $EVIL\_RESOURCE, because you need this for your next generation gardening device. "Oh and that evil looking machine there?" * "Not to worry dear innocent person, this is a new generation of Kitchen-Aid with plutionium based batteries, completely safe." [Answer] By doing it every couple of years in some totally innocent way. Some years you spend sailing in the Southern Ocean, some years you spend 6 months skiing in the Alps or solo trekking across the Australian outback. Eventually they get used to your disappearing for months at a time and it taking them slightly longer than they'd like to work out where you are this time, by which point it's already too late. [Answer] ## Hide what you do, not where you are Hiding what you do is a subset of hiding your person since if you hide your person, you also hide what you do. Given the high degree of surveillance on your person, it will be easier to hide a portion of your daily activities instead of *all* your activities. You will need to make regular public appearances to avoid suspicion (as much as possible). ## Locating the Lab Your lab will need to be located in a place where you go frequently already or can get to with relative ease without being observed by anyone else. Flying directly to your lab won't work because all flights are tracked and turning off that tracking is very suspicious. Also, there's the convenience factor of being able to get to the lab regularly so you can keep working. A project that requires you to travel 2 hours to get to won't get much attention. ## Within your Lab You'll need to adopt the following procedures to hide your activities * All electronic devices are checked at the door. No cell phones, no phones, no pagers, no digital assistants, no laptops, no USB drives * Three factor authentication to gain access to the lab. * Soundproof the entire lab. * Build a completely self-contained ventilation system with airlocks. * Build a Faraday cage around your lab. Hell, build two cages, just to be sure. * Line with substantial and multiple layers of concrete with air gaps in between. This way, if your working with some really nasty gamma ray sources, the gamma rays won't leak and give you away. You'll need to be very careful that *you* don't become radioactive too. These concrete shells will also make it nigh impossible for sound to get out of this lab. * Provide power to the lab using an AC-DC-AC converter. This will strip out any information that may be passed over power mains. There are significant heat waste to this approach but you're a billionaire and secrecy is super important. * Introduce very strong controls over the electronic firmware of the equipment you install. Be able to wipe all firmware and reinstall from trusted sources at will. Introduce regular rebuilds of system firmware and operating systems from trusted sources to ensure that *if* your machines are compromised, they can be rebuilt and made trustworthy again. * Hire a penetration testing team to continuously attack your lab. Only direct physical assault with explosives is forbidden. Social engineering, van Eck phreaking, hacking, everything else is on the table. This is an exceptional situation requiring exceptional countermeasures. Remember that you're fighting against one of the world most powerful nation-states. The CIA has an unlimited budget, best to be prepared. ## Supplying your lab This will depend a lot on the nature of your doomsday device. ## Operational Security Hire the absolute best opsec people you can find to plan and run your operational security. If you spend $200 million on an impenetrable lab but forget to take your phone out of your pocket before you walk in, you're really going to be kicking yourself when the CIA busts down your door. [Answer] Serious Answer: Obviously, you need to have your best friend be the head of the CIA so he/she can cover up for you, foil all the go-getter young CIA agents trying to stop you. That's what every other super villain does in Hollywood. Reverse Psychology Answer: Even better, reincarnate as a different person immediately! They will never see you coming! It works just great, try it! [Answer] Riffing on a couple of the other answers, fake your coma. "In the news, eccentric billionaire Pavel's private jet crashed on takeoff during a business trip to Switzerland. He was airlifted to a private clinic where he was announced to be stable but comatose. Doctors are unsure at this time if he'll wake up." Then at the private clinic you have a fake body set up in a super advanced life support pod. The body will mimic you perfectly, with real feeling skin, warm breath, pulse, etc. The pod will take care of "feeding", "waste elimination" and all of the other things that a nurse might have to do so that no one will get suspicious. When the intelligence operatives come to check it out they'll see that you're decoy is "alive", with a EKG and brain activity, but that it's all consistent with a coma. Meanwhile you've changed your face and are just a mid level manager in your company that is tasked with keeping stuff working while the boss is in the hospital. This will give you the ability to move around and do stuff while appearing to boring to be someone that needs to be watched. **Edit:** Or as VSZ suggested you could avoid a few problems by finding a similar looking hobo, putting them into a medically induced coma (which could be part of the actual cover story), do a bunch of plastic surgery and say that it was required because of how bad the crash was. So long as the hobo doesn't wake up or die you'll be fine. Dying wouldn't be the end of the world, it would just make things a little more difficult. **Why coma instead of death?** Dead people can't usually hold positions or own assets. If you die then your estate goes into probate, and it's possible that your accounts will be frozen. This makes things difficult. If you are in a coma then there will have to be a regular flow of money to pay doctor bills and stuff, and so it is a way to launder the money that will be needed to work your evil plan. [Answer] **Die !!!!!!!!**(just fake it) You can do this **tomorrow** , have a car crashed , and bring a sealed coffin home. Let people in your family cremate it.(or simply crash your private jet in to the ocean but Do this step fast.) **Now you are dead** Ok now you have all the time you need, grow your beard , wear sunglasses (also can do a plastic surgery if possible), then **you can travel** even . People will not notice, even if they do they won't believe it. Because you are dead. **Basically You can do whatever you want** Because nobody cares about the actions of a dead person. **Coming back to life** You can peacefully make the doomsday device and reveal yourself, and you don't have to worry about any agencies or government because you now have a cute little **doomsday device** in your hands . **One problem** Most of your money and assets will be not there when you come back , but do you really have to worry? Not at all , because now you are the most powerful man in the world, ask The world to be yours . The world will be yours , because no one wants a doomsday ! [Answer] In Forensic science, Locard's exchange principle holds that the perpetrator of a crime will bring something into the crime scene and leave with something from it, and that both can be used as forensic evidence. If you're a billionaire with evildoer plans, you have to remember that even if you go underground and stay obscured, you will still leave a tracable footprint. Communications you send out into the modern world becomes a footprint. Acquiring assets for your evil plans leaves a footprint and would set off warning bells. You can sneak into a country like North Korea, you still leave a footprint. There was an evildoer who was trying to live in a house and go undetected. For years people thought he was really living in a cave. But he was brought down because his communications were trackable and he had to remain in communication to be relevant. This has brought down many similar evildoers. The best course of action is to remain hidden in plain sight. Even better, use your wealth to change your world to help you achieve your goal. If you set the right goal, they may pin a medal on your chest for being a humanitarian. [Answer] Easy as 1-2-3. Acquire a controlling interest in a company working on a doomsday device. Few things to keep in mind: * I don't recommend Boogle, for it is already on a radar. And don't even think of Halliburton; your funds are not sufficient. * Try not to expose yourself too obviously. I suppose you know how to set up fictitious owners. * Do I need to continue? PS: Please contact me privately, and I will steer you in a right direction (standard fee applies). I love to steer billionaires (mwahaha). [Answer] You don't disappear. Why you want to hide for a year? To think about your plans? And you are a billionaire? Step right this way to your private jet that will take you from many places to different places. That's how you travel. You also post this on instagram "this is me at Taj Mahal with my Bentley". While in Taj Mahal you meet with person of your interest. Then you go to your jet, fly for 5 hours (you actually work and think and plot) to Tokyo where you take photos in gadget section of the city and with kawaii girls and cute boys. Oh, you bought this cool new japan toy "Hakune Muku"? It's part of your device. You post photos of you and almost naked women in a bathtub in Dubai but in reality the waiter is your engineer. So, think and work in the solitude of your jet. Visit places you want to visit and many more (the CIA would need to sort out 1 place of interest form 100 you visited). Shake hands with people, was it really Dalai Lama or not, Maybe it was but he's assistant was also your associate. And how and where you build your doomsday device? In your museum of doomsdays devices of course! From many pointy sticks through Little Boy and Fat Man to replica of Bond villains diamond satellites. And somewhere there is this once device that actually will work. Good night. And have a plentiful year :) [Answer] # Create a distraction. The point I felt missing in this mastermind plot.... Hire /ask a secret friend to run some (terrorist) organization while you maintain a pretty face in politics/media while secretly working on D-day machine. Something similar happened in [death note](https://en.m.wikipedia.org/wiki/Death_Note). ]

[Question] [ Is there anything about the decimal number system that conveys any advantages over any other number system? So is it any more likely that some other alien race would use base-10 numbers in everyday life or are they just as likely to use say... base-8 or 12 (8 fingers and no thumbs, or 12 joints in the fingers)? base-3? 16? 29? 100? Or is there some useful property in base-10 numbers beyond us being able to count with our fingers? [Answer] # Nothing special about 10. It's likely that the aliens would develop a system with a [radix](https://en.wikipedia.org/wiki/Radix) (base) of whatever number of fingers/toes/tentacles that they had easily available to count with. And as TheBlackCat pointed out, there are many options beyond that. There's even different base systems among humans. For instance, the Babylonians used a [base-60](https://en.wikipedia.org/wiki/Babylonian_numerals) system, the french used a [base-20](https://math.stackexchange.com/a/391246/324252) (they say 4\*20 instead of 80 even today), and the Wikipedia article for [base-6](https://en.wikipedia.org/wiki/Senary) says that several cultures have adopted that system. If you wanted to, you could even make it a plot point that different cultures use different bases. Perhaps two major cultures view their particular radix as having religious significance, and the fact that they use different bases is a point of contention and occasionally war between them. And there's no real advantages to the number 10 either. In fact, there are people who [think we should switch to a different radix](https://io9.gizmodo.com/5977095/why-we-should-switch-to-a-base-12-counting-system) so that we'd have an easier time dividing. As discussed on [reddit](https://www.reddit.com/r/askscience/comments/s9ibb/is_there_any_real_advantage_to_using_a_base10/), the main tradeoff between having a low or high radix is the number of digits you have to memorize vs how long the resulting numbers are. Low radix means few digits but long numbers, and high radix means lots of memorization but short numbers. [Answer] ## Absolutely not. Even on Earth, we routinely use other bases. Computer scientists use binary (base 2), hexadecimal (base 16), and octal (base 8), as well as decimal, very routinely. Various world cultures (past and present) have used number systems with all kinds of bases. There is a base-12 number system called [Dozenal](http://duodecimal.net/archives/duodecimal/duodecimal.html) (or Duodecimal) that has some real advantages over base-10 for us (such as having more factors, so it can be more easily divided). We use base-10 mainly because we have ten fingers. Whoopee. Base-12 is a better system in many respects, but probably the main reason we aren't converting is that base-10 simply is too well established. And you could make the same case for other counting systems with other advantages. For the above stated reasons, aliens would not be any more likely to use base-10 than any other reasonable (to them) radix. ## How to communicate, then? You didn't specifically mention a need to communicate with these aliens, but as a sort of bonus answer, here are some points to consider if communication is required: Often people advocate just using binary or unary (base-1. Think hash marks) as sort of a lowest common denominator. But really, any base will do as long as you define it before you start communicating. Alien language is a whole different topic, but if you can convey something like the following, you're set: ``` apple banana | kiwi || plum ||| ``` You now have established a link between your base-4 number system (apple = 0, banana = 1, etc.) and its base-1 equivalent. If your extraterrestrial buddies can't do *that* conversion, they probably stole someone else's spaceship. [Answer] Others have immediately pointed out that base 10 is a human thing. Note that bases 12 and 60 are more “for a reason” and may show up in the aliens’ cultures too! (More on that below.) But let me point out that a “base” (positional system) is not the only way to go. Even we know about Roman numerals. I’ve seen authors be “more alien” by defying the very concept of a base. ## balanced ternary For example, Robert L. Forward had one alien culture use a [balanced ternary](https://en.wikipedia.org/wiki/Balanced_ternary) code, which is a base but not as we know it. It is positional, but each position can have positive and negative values. This (not necessarily ternary) could show up in the way [abacuses are made and merchants compute](https://en.wikipedia.org/wiki/Salamis_Tablet), and give an early apprciation for zero and negative numbers relative to our own development! ## irregular bases They might have an irregular hierarchy of bases rather than the same base in every power, with weird culturally significant rules. The writing system may obscure the fact that they are in fact using a “modern” positional system, because they retrofit it into their old writing system which originally used an irregular system. Murphy gave an example of this based on anatomy. But I’d like to point out that we do that with “traditional” units in many cultures, and the idea can be formallized and refined using number theory: Look at the idea of an [anti-prime](http://mathworld.wolfram.com/HighlyCompositeNumber.html) (look for the [Numberphile video](https://www.youtube.com/watch?v=2JM2oImb9Qg). A subset of anti-primes such that each is a integer multiple of the previous gives (1, 2, 4, 12, 60, 180, 360, 720, 5040, …) Now we continue using grouping hieararchies like that, but write each coefficient in decimal (like 36 minutes, 22 seconds). If they had a writing system more like syllabic glyphs, you can imagine the number being written as an ornate picture. This might evolve into a refined “modern” system that’s base 60 in its mathematical properties, but written with digit groupings having hiarchial clumpings reflecting the subsequent antiprimes. ## even more alien They may not associate small natural numbers with unique glyphs and use multplication (whether by positions or other notation) to form bigger numbers. Look at the [theoretical formation](https://en.wikipedia.org/wiki/Natural_number#Constructions_based_on_set_theory) of naturql numbers — it doesn’t look like a “base” at all, does it? Knuth wrote a [very cool and interesting book](http://www-cs-faculty.stanford.edu/%7Eknuth/sn.html) on [surreal numbers](https://en.wikipedia.org/wiki/Surreal_number) from the point of view of two people decyphering markings in rocks. [Answer] I like some of the other answers but **let's go weirder.** Technically you can even have a base system which varies along a number or has its digits in a complex order. Imagine a number system where, in order of evaluation: The first digit is base 8 The second digit is base 2 The third digit is base 10 The fourth digit is base 12 And when being written down they order them [third][fourth][first][second] So the number 5 would be 0050 9 would be 0011 16 would be 1000 160 would be 0100 (hopefully I've not messed any of those up) Each position can even use entirely separate symbol sets or they could use the same symbols but where 1 symbol can mean different things changing by position. And then loop for arbitrarily large numbers. perhaps it's a species with 8 tentacles, 10 fingers, 8 toes and 2 trunks who see it as an obvious system and order their numbers by the positions of the appendages on their bodies and their relative ease for use in counting. For context I once had to write an encoder which could accept a number an translate it using arbitrary symbols, order etc and found it perfectly logically consistent if somewhat confusing. I would call a system like this slightly less likely than a simpler system using a single base but it's an option. [Answer] ## No bases are required for counting Most of the answers make an assumption that isn't quite correct. The assumption is that a base is required; in a universe with no rules about how life can develop, this is not the case. **Why do humans have bases?** One of our major limitations as a species is related to counting. Most people can distinguish between 2 and 3 items without counting. Many, but not most people, can distinguish between 5 and 6 items without counting. ([this is called Subitizing](https://en.wikipedia.org/wiki/Subitizing)) But nobody has the neurological apparatus to distinguish 21 and 22 items without counting. So we are hard wired to tell which tree has more fruit if there are just a few apples, but not if the tree is filled with fruit. Contrast this with out ability to talk and listen. When speaking, we can issue 1400 muscle instructions/second. When listening, we can identify instantly which of the 75,000 words or sounds we know have been used. Even more computational ability is required to catch a baseball on a windy day in the outfield, or block a soccer/football penalty shot. My point is our minds have to ability to work in numbers larger than 10$^6$, we just don't have the ability do it with counting. We evolved complex systems for communication, vision, image processing, and movement, but there was no evolutionary reason to develop a very complex counting and mathematical brain. We can view this as a major weakness of our species. **What about non-terrestrial creatures?** We have English words for numbers we are all familiar with: one, two, three, four, five, six, seven, eight, nine. Imagine an alien that had a mind that was powerful enough to distinguish between 124,523 and 124,524 ping pong balls instantly. It is likely that they would have a *different word* for each number. (err, if they used words) Source A book called "What counts" by Brian Butterworth. A very good read. He says because we don't have a math processing center like we have for vision, emotion, or memory, the brain uses a work around. Our number skills are based in the portion of the motor cortex related to finger control (p244), which is why children use their fingers to learn counting, and why we must use a base. (Note, because we have only 10 fingers, this is why human bases are generally <100). He also mentions that we learn addition before subtraction, and multiplication before division, and our susceptibility to the [Stroop effect](https://en.wikipedia.org/wiki/Stroop_effect). Even more interesting the [numerical stroop effect](https://en.wikipedia.org/wiki/Numerical_Stroop_effect). **Edit:** Butterworth also reviewed anthropological literature about the origin of a counting; and found that many tribes did not use a base; one tribe (I think in Australia? Need to look it up later) they only had words to count to 3. After that, they would use the fingers, toes, eyes, ears, nose,etc. of themselves, and if they needed more, other people as well. They didn't need words to understand relatively large numbers. If I recall correctly, the anthropologist didn't report what happened when the number was too large. [Answer] There are a few important things to note, in addition to all the things mentioned. As said, 10 isn't special, other than humans having 10 fingers. In addition, *60 isn't special, either*. 360 is special, but only to humans, because that's really close to the number of days in a year. Early calendars were based on 360, and (some) early number systems co-evolved with their calendars. (If you've ever played with the GRAD setting on a scientific calculator, having 400 GRADs in a circle would make much more sense than the 360 we ended up with.) The Sumerians liked 60 because it divides so nicely into 360, and 12 is nice because we have 5 fingers on our hand, and 5 12s gets us back to 60. Why are there 7 days in a week? Because 7 divides so cleanly into the 28 days in a "month" - i.e. the number of days in our lunar cycle. I did a research project on the evolution of number systems as part of my undergrad work. [From 1 to 0](http://rads.stackoverflow.com/amzn/click/0670373958) was the seminal work on the topic. [Number words and number symbols](http://rads.stackoverflow.com/amzn/click/0486270963) was also a big chunk of my research. An alien species (assuming, like us, it couldn't divest itself of what it's been used to for millenia of growth) will base their numbers on whatever is relevant to them. Number of appendages is important, but so is working with constants given to you by your environment. You may get a really interesting system by there being multiple moons or stars in their system. One last interesting note - humans and other animals have an ability to easily recognize groups of up to 4. After that, it becomes increasingly difficult. Even if we had 8 fingers per hand, it's possible tally marks would be broken up in 4s or 5s, just because it's easiest to read them that way. **EDIT** I feel a need to add a bit more; the comments to my answer are arguing over minutiae, and it's obscuring the important point. The number system of your society will form extremely early on - it will coincide with the birth of your society and the formation of their earliest languages. To know what your alien's number system will be, you have to think of how their society was first created, and what phenomena they would observe while doing so. Number words start with the simple, familial concept: "There is me (1), us (a few), and others (many)." The next immediate growth is grouping: "I thought there were more of my family. Is someone missing? How many are we?" At this point, you start grouping using the number of some appendage. For humans, the easiest thing is the five fingers on your hand. They're always around, and you can pick up and put down each finger as needed: "There's me. There's Ugg. There's Ock. There's Uga. There's Gug. That's one hand. And there's Gaa. That's one-hand, one-finger. We were one-hand, two-finger yesterday. Where's Kaa? WHERE'S KAA????" Number concepts don't evolve beyond this much (humans went from one hand to two, then stayed there) until you go from familial to tribal, and have enough safety for there to be someone who focuses on observing. This would be a priest, or a medical man. They'll notice something that recurs on a predictable scale. It has to be a predictable scale, really, because there is not sufficient level of intellectual sophistication to find a non-regular repeating pattern. At this point of time, the scientific discovery **is** that the pattern exists. That "ability to predict the future" is part of what will make this observer powerful. Whether (s)he will "make the sun/moon come back" or will "make water erupt from the ground" (a la Old Faithful), their knowledge will make them powerful, so they'll develop it. Whatever number this thing recurs at will likely become the society's radix. It's likely that this counting will be of something astronomical - either day cycles or moon cycles - because there aren't much more precise measurements. Hours won't exist for tens of thousands of years yet. *This* is what you're contending with when you look at a number system - concepts that go back as far as society itself, at the formation of a species' first words. It's important to realize that numbers weren't chosen by the society. They found the numbers based on themselves and their environment that best helped them to survive, and their culture, math, and science all grew up based on these values. The cultural inertia of such numbers is really hard to overcome. Number words - and the numerical systems that derive from them - must have their origins in observable phenomena. At the time that the number words are formed, there just isn't enough strength in the culture for them to form any other way. There will be little decision-making in this process - it would have to be an easy enough decision to make that society would actively make it over tens of thousands of years of the most primitive culture possible. A spacefaring society will have developed their mathematics enough to realize there are other, likely more efficient bases. Their specialists will use them in their specialist tasks (as we do for computers, and for speaking in abstract number theory about better bases.) Particularly, their rocket scientists could use number constructs that most others do not. But the people will still use whatever number system their society grew around, based on their physiology and their local astronomy. [Answer] ## Numbering Systems Are Perception Based I would say any type of science is based on the consciousness of the entities developing/using it. For example, most people conclude many humans use base 10 numbering because that's how many fingers we perceive oursevles as having through our five senses. Our perceptions through our senses populate our consciousness with content, and our thinking coagulates around content present in our awareness. So, any sciences developed by our consciousness have a good chance of being developed based on the most common systematic/reliable perceptions found in consciousness. In this way, one can say science is based on consciousness, on our perceptions. For example, it could be argued that it is not so much that we *have* 10 fingers, but that 10 fingers are *very prominent in our awareness*--because they permeated our awareness so fully during our evolution, many humans chose to or inadvertantly began to think in terms of tens. So, if an alien race more often has something other than tens in their awareness, their numbering systems will most likely be based on that content. Given the enormous range of types of concepts possible to perceive, and tens only being one of those possibilities, it might stand to reason that 10 base numbers are only one out of an infinite number of possible numbering systems. ## How Alien Is Alien? In addition, if we take the term "alien" as meaning "different from us", then the more alien a race, the more alien their numbers will be to us. There is a range of concepts humans do not consider alien/foreign because they are considered within our range of plausibility. However, any alien race dealing with concepts outside that range of familiarity will likely begin to develop sciences and numbers outside our range of recognition. So, an alien race that is numerous [standard deviations](https://en.wikipedia.org/wiki/Standard_deviation) away from human (i.e. more alien than we can comprehend) will likely develop sciences based on concepts we cannot even relate to easily. For example, it is extremely difficult to imagine an alien race developing sciences without numbering systems, yet technically speaking, it is possible they use concepts too different for use to comprehend instead. Our human consciousness defaults to think in terms of numbers as being an unalienable foundation of science, something science cannot exist without. However, if one extrapolates based on the idea that standard deviations in thinking can be infinite, and yet human can only comprehend thoughts within a finite range of deviation, then it becomes almost a certainty that somewhere in the infinity of possible universes in an infinite omniverse, there would be sciences with numbering systems too alien for us to comprehend or even begin to imagine. [Answer] **There is nothing special with the decimal system, except for being directly based on the *number of fingers* for humans.** Alas, most other numbering systems ([duodecimal](https://en.wikipedia.org/wiki/Duodecimal), [sexagesimal](https://en.wikipedia.org/wiki/Sexagesimal), etc) also have some underlying ties with our fingers. See: you can count using only one hand up to 12 by using your thumb to point to each of the other fingers bones. If you use your other hand, you can count how many times you've done this (which is actually like counting in decimal in the second hand) so that you reach 60. To be more thorough, in modern times we still use many [numbering systems](https://en.wikipedia.org/wiki/Numeral_system) (positional or not). We still use roman numerals for some things, while we also use both duodecimal and sexagesimal systems to count time. If we are talking about subsecond measurement, we also use decimal, and if talking about multiple days we usually also use decimal. For angles, we also use a mix of sexagesimal and decimal. Talk about legacy development! That says something about the Sumerian influence on our culture, from thousands of years ago! By the way, even [Mayan](https://en.wikipedia.org/wiki/Maya_numerals) or even [Prehistorical numbering systems](https://en.wikipedia.org/wiki/Prehistoric_numerals) also rely on some form of base-5 to facilitate counting with your fingers and that show when writing the numbers. Remember that ease of learning is a big part of the success of a numbering system. If some people find math hard today, imagine how it was before it permeated our lives. By the way, Robert Heinlein briefly touches the subject of contact with an alien society with a 3-based numbering system in *Stranger in a strange land*. [Answer] Don't forget [divisibility rules](https://en.wikipedia.org/wiki/Divisibility_rule). Writing in base ten makes it easy to distinguish between odds and evens. And identify multiples of five. And multiples of three, too, by adding the digits. So base ten is good for quick identification of multiples 2, 3 and 5. Is it a coincidence that these are the lowest three primes? Probably. Other than that, besides easy divisibility-checking for the first three primes, there's nothing special (to my limited human mind, anyway) about the base 10 system. In fact, a culture could pick a few other bases, were they interested in divisibility. base 6 and base 16 both allow the same methods as above. base 36 or base 66 are arguably even more useful for this, but perhaps too many symbols to memorize (see emo bob's [post](https://worldbuilding.stackexchange.com/questions/63825/alien-number-systems-is-the-decimal-system-special#answer-63827)). [Answer] I think it **may** depend largely on the alien's physical makeup and/or cultural history. As others have pointed out, humans use base-10 (because of number of fingers), base-60 (historically for easier calculations) etc. So it is completely conceivable that an alien race may prefer base-3 (ternary). Perhaps this alien race has an Artificial Intelligence origin (intelligent machines based on computers) and some analyses here on earth have shown that a base-3 system would be the most economical way to build a digital computer (but only slightly more so than base-2 (binary) or base-4). Or maybe they have some special evolution that makes their brains very much like a biological computer, and selection selected the most economical brain structure (ternary) due to resource limitations. Thomas Fowler built a *balanced ternary* (-1, 0, +1) computer out of wood in 1840, and had this to say: > > I often reflect that had the Ternary instead of the denary [decimal] Notation been adopted in the Infancy of Society, machines something like the present would long ere this have been common, as the transition from mental to mechanical calculation would have been so very obvious and simple. > > > More reading: * [Radix economy](https://en.wikipedia.org/wiki/Radix_economy) * [Ternary computer](https://en.wikipedia.org/wiki/Ternary_computer) [Answer] I remember reading an article about an electrical circuit that implemented base negative two math. Some examples with four "bits" valued (-8, 4, -2, 1): `0000 = 0 0001 = 1 0010 = -2 0011 = -1 0100 = 4 0101 = 5 0110 = 2 0111 = 3 1000 = -8 1001 = -7 1010 = -10 1011 = -9 1100 = -4 1101 = -3 1110 = -6 1111 = -5` [Answer] It may be that fibonacci is an earthling sequence or it may be a universal law of biology, it's hard to say. Decimal may be significant in that it is the product of two fibonacci numbers 2 \* 5. Perhaps aliens with a set of 6 fingers on 2 arms that evolve base 12 would be much less likely. [Answer] There's nothing special about base 10. It's just what we learned when we were kids, because we have 10 fingers. If you do a lot of binary or hexadecimal arithmetic, it feels just as natural. However, let's assume that we count base 10 because it was passed to us by our caveman ancestors who learned to count with their fingers. Let's dig deeper. Why did we simply count fingers, and not use binary numbers? If we used our fingers to represent binary numbers, we would be able to count to 1023 using our 10 fingers. That's much more powerful than simply counting to 10. Part of it is the anatomy of our fingers. It's hard to represent numbers like 1010101010 using our fingers. But an alien species might not have that dexterity problem. Another limitation is the human brain. Counting to 10 doesn't use much brainpower. But our caveman ancestors probably didn't need to count to 1023. A more intelligent species probably wouldn't mind so much. If an alien species only had 4 fingers, they'd only be able to count to 4 by counting fingers. But using binary, they'd at least be able to count to 15. Now suppose there was an alien species who represented binary numbers when counting with fingers. When they invented pen and paper, their finger counting method would have naturally extended to writing binary on paper. They'd have the SAME method of counting with fingers as with paper and pen. They'd only have to teach their children one method!. Think about how it is for humans. We first teach our kids to count with fingers. Then, when they reached a certain age, we teach them the decimal characters, and teach them to convert what they've already learned to the new system. Some people would argue that an alien with 8 fingers would use base 8. But using my argument above, I'd say that an intelligent species with dexterous fingers would have counted base 2 regardless of how many fingers they had. Nothing special about any of your bases. They all are belong to us. [Answer] Different human civilisations used different bases. The Bablonians used base 60 the Maya base 20. <https://en.wikipedia.org/wiki/List_of_numeral_systems> shows how many possible bases are used by different languages. Even within our own language we don't only use base ten. On side of a clock shows 12 hours. There are 2\*12=24 hours per day and not 10 or 100 hours. There are 12\*5=60 minutes per hour. Having 60 minutes per hour means that it's 1/3 of an hour is a nice round number of 20 minutes. If the hour had 100 minutes 33.333 minutes wouldn't be a nice round number. Rumours have it some tribes in America still uses a system of measuring lengths that uses base 12. In Europe the French tried to get everything normed to base 10 and the common base is useful but even the French didn't succeed in getting the 10 day week. They tried but people liked their 7 day week too much to switch. [Answer] ## Base ten is convenient for estimation As I write this, every answer declares there is nothing special about base ten. I think one point that's been missed is the value of a digit as an order of magnitude. For example, consider three interpretations of this statement: ``` 10 + 1 ≈ 10 ``` * In base two (the smallest possible base), this means "three is approximately two". The difference between three and two is sufficiently large that you need a relatively loose definition of "approximately" to consider that statement true. As a consequence, you can't use it for anything much more precise than Fermi estimation. * In base ten (like we use in the Western world), this means "eleven is approximately ten". In practice, this is useful for engineering applications; for instance, it's why [we can treat flows with M<0.3 as incompressible](https://engineering.stackexchange.com/questions/7344/why-is-mach-0-3-the-threshold-separating-compressible-and-incompressible-flow) (which allows us to use a much simpler set of equations). It's loose enough that it applies to a significant fraction of cases, but restrictive enough that we can actually trust the results we get from our estimation, which we couldn't do under the base two interpretation. * In base one-hundred, this means "one-hundred and one is approximately one-hundred". If you use this as your rule for approximation, you will have more accurate approximations, but it drastically restricts the situations where you can estimate; for instance, in the Mach number calculation above, we would not be allowed to treat freeway speeds (120 km/h) as incompressible. So base ten is nice because moving a digit one space to the right means you can neglect it in your calculations. However, if your aliens have spent millenia with technology that requires extreme precision, they may find that our one-part-in-ten estimation criterion isn't useful for any of the problems they're currently solving (like how the "three is approximately two" rule isn't really useful for us). So maybe they have a much larger radix. ## Small factors are easier to estimate by hand Note that above, we make an argument for why base ten is more useful for humans than base two or base one-hundred, but we don't know that it's actually optimal- e.g. what about base nine or base eleven? One drawback of the decimal system (and a reason why imperial measurements are still used in cooking) is that humans are pretty good at splitting things into twos and okay with threes, but fairly poor at divisions that have larger prime factors. For example, suppose you have a volume-unit of some substance and you'd like to separate out some smaller unit: * In the metric system, you have a litre. Getting anything smaller (a decilitre, centilitre, millilitre, ...) requires you to be able to break something into tenths (or at least fifths and then halves). Humans generally need tools like measuring cups or graduated cylinders to do an adequate job of this. * In the imperial system, you have a gallon. Divide by half twice, and you have a quart. Do it again and you have a pint. Once more and you have a cup. Three more times and you're down to a fluid ounce, once more and you have a tablespoon. Typically, humans are much better at correctly saying "those $n$ quantities are equal" when $n=2$ than when $n=5$, and so this gives accurate results even in the absence of tools. Now, maybe your aliens have some exotic biology like five eyestalks or seven hands. They might then evolve a psychology that allows them to easily and accurately compare a higher number of quantities (e.g. "is the weight I'm holding in each hand about equal?"), which could in turn affect the radices in which they can efficiently perform mental math; they'd likely prefer to record their figures in a notation which reflects their bias. ]

[Question] [ [This question about time dilation](https://worldbuilding.stackexchange.com/questions/106506/time-dilation-difference-of-two-spacecraft-at-different-relativistic-speeds-if) got me thinking. The speed of an electron through copper is a whole heckofa lot slower than the speed of light, but if I understand the limits of relativity correctly, the electron can never travel faster than the speed of light anyway. Now, let's ignore the ultra slow [drift velocity](https://en.wikipedia.org/wiki/Drift_velocity) (<<0.01c) and stick with signal propagation, also known as the [velocity factor](https://en.wikipedia.org/wiki/Velocity_factor) (~.95c). If you're not aware of the difference, consider a [Newton's Cradle](https://www.youtube.com/watch?v=0LnbyjOyEQ8). The middle balls hardly move (drift velocity) but the last ball in line goes winging off into space (velocity factor). So, if my ship is traveling at 0.95c then the "ball at the end" of my Newton's Cradle is moving at the same speed as the ship, and since I'm dealing with relativistic problems, it's standing still, right? Which means, if I'm correct, my computer is at a standstill. Am I correct? Will humanity need to come up with a non-EM logic board to perform course calculations for relativistic ships? Or will relativistic speeds always be limited by the computational speed required to make course corrections? (Making massively parallel computing a very desirable thing). [Answer] This is a pretty interesting topic, and one of the things that makes special relativity so mind blowing. But the answer is: From your perspective **on board the ship**, the computer will function just as fast as it would if you were using it on Earth. After all, physics doesn't care about which inertial frame of reference you're in, so it wouldn't make any sense for the computer to work in some frames and not in others. However, from the outside perspective **of a "stationary" observer**, your computer would indeed be running slower -- though not at a standstill. **Note:** I put the word stationary in quotes because in special relativity, there's not really such a thing as stationary. All motion is, well, *relative*. What I should really say is "an observer moving quickly with respect to the spaceship", but that's not nearly as catchy. These seeming paradoxes are explained away with the help of time dilation, length contraction, and the relativistic velocity addition formula. I might go more in depth here later if I have the time, but suffice it to say that the main place your thinking is going wrong is that you're unconsciously assuming that time and space are absolute. In reality, they start stretching and contracting when you move between different reference frames, and the end result is that the computer works just fine for the astronauts using it, but looks like it is running slow for outside observers. As an analogy, note that all biological processes take place at sub-light speeds, yet the astronauts will not perceive themselves as slowing down. **EDIT:** Here's a slightly more math-y explanation, for those so inclined. To truly channel the spirit of Einstein, rather than spaceships and electrons I'll talk about trains and baseballs. The concepts are exactly the same, but this is perhaps more concrete. Anyway, suppose little Jimmy is standing on top of a speeding train throwing his baseball, as kids are wont to do. Say the train is moving at $20 m/s$, and from Jimmy's point of view, he's throwing the baseball at $20 m/s$ in the direction the train is moving. Now, how fast will old man Jenkins, who's standing on the platform, see the baseball travelling? Why, $40 m/s$, of course! How do we know? Well, we simply added the velocity of the train and the velocity Jimmy throws the baseball at, since the baseball is already traveling at $20 m/s$ just by virtue of being on board the train. Now, suppose the conductor got bored and told the engineers to speed the train up to $0.95c$, while Jimmy undergoes intense physical training to get his fastball up to $0.95c$ as well. Now suppose Jimmy has lived on this train his whole life. From Jimmy's point of view, he's just standing on a stationary train throwing a fast ball at $0.95c$. No biggie. From his point of view, the Earth is the thing moving really fast, while he's standing still and throwing the fastball at sub-light speeds. So there's no problem from his end. But what about old man Jenkins? Surely, he'd see the fastball moving at $0.95c+0.95c=1.9c$, violating the speed of light, right? **Wrong!** Due to some clever arguments (that actually [only require basic trigonometry to follow](https://web.pa.msu.edu/courses/2000fall/PHY232/lectures/relativity/dilation.html), if you're interested), old man Jenkins will actually see everything Jimmy is doing being done slower than normal and squished along the direction of travel. The net effect is that to Jenkins, the velocities of the baseball and train won't add in the usual way. Instead they'll follow the relativistic velocity addition formula: $$u = \frac{v+u'}{1+(vu'/c^2)}$$ where $u$ is the speed of the baseball old man Jenkins measures, $v$ is the speed of the train, and $u'$ is the speed of the baseball measured by Jimmy. Plugging in the numbers, we get $u=0.9986c$, rather than the $1.9c$ we would naively expect. Now go back and mentally replace every instance of the words "baseball" and "train" with "electron" and "spaceship", respectively, and I think you'll find the answer to your question. [Answer] ## Approach the speed of light *with respect to what*? Right now there is an electron flying around in a [synchrotron](https://en.wikipedia.org/wiki/Synchrotron_light_source) somewhere which is moving at an appreciable fraction of the speed of light with respect to you and your computer: which means that you and your computer are moving with an appreciable fraction of the speed of light *with respect to that electron*. So, has your computer become slower because of this? The point is that all movement is relative, and *all the laws of physics are the same in all inertial frames*. There is no aether, there is no fixed space. We are all moving at relativistic speed with respect to some frame of reference; this cannot possibly affect the laws of physics in *our frame of reference*. [Answer] From all of the answers and the comments therein, I think the issue is simply a lack of understanding of relativity, so this answer is mostly just going to be a primer in how to think about it. I am not a teacher, nor a physicist. Forgive me if I make errors, and point them out so I can correct them. However, I am friends with an excelent physics teacher, and I got the privilege of sitting in on his class when they were learning relativity. He started out with a few of the more interesting thought experiments, like the one with two flashing lights on a train. He kept going and going, and you could watch the students getting more and more perplexed. Finally one student slammed his hand down on the table and yelled "Bull-----!" My friend did not miss a beat, and immediately replied, "Good! *Now* class can begin!" If the claims of relativity do not bug you at first, that means you are not paying enough attention. They *should* bug you. They're freaking weird! Now I am just writing this text as I go. I don't have the privilege of waiting until I hear you shout "BS!" at me, so I have to take a different approach. I find it's effective to make sense of relativity from a historical perspective. The original investigators got to think the same sorts of naive theories that we all think of, and as relativity evolved, they tried to call BS, but couldn't because the evidence showed that the universe was *actually* that weird. Before Einstein, there was Maxwell. Maxwell's equations were a very effective set of equations for modeling the propagation of EM waves. They predicted basically everything we could test when it came to EM waves. However, there was a catch. In Maxwell's equations there was a really natural derivation of a "wave velocity," that is the velocity that an EM wave propagates in. Now if we do any of the standard experiments where I stand on a train and throw a baseball or something, we're used to the idea that I perceive the baseball as traveling slower than you perceive it when you're on the ground. But Maxwell's equations only offered one wave velocity for EM radiation, c -- the speed of light. The natural assumption that many scientists made in that age was that light traveled through some sort of medium, just like soundwaves travel through air. Thus the natural "privileged frame" for defining the speed of light was the frame of this medium, called the Aether. And, of course, we expected it to behave similar to how air does, with doppler shifts and shock waves and what-not. There were other theories too, but Aether is the most fun to talk about, and it lines up *directly* with your concept of an electron traveling at a high velocity with respect to a ship that is traveling at a high velocity. At some point, scientists started experimenting to try to pin down this Aether's frame. They did many experiments, the most notable was the [Michaelson-Moorley experiments](https://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment). The idea behind these experiments was that the Earth is clearly orbiting the sun, so its velocity with respect to the Aether should change over the course of a year. The experimenters just had to look at the velocity of light waves in a couple directions, and see how they differ. Then we could make calculations about our movement through the Aether. When they compiled their data, they noticed a *really* strange thing. The velocity of light was the same *in all directions*. It didn't matter if you pointed the light with the orbit of the Earth, or against it, or if the Earth was on one side of the sun or the other. The measured speed of light was the same every time. This meant one of a few things: * The Earth really was the center of the universe, being connected directly to this heavenly Aether. * The Aether was somehow being "drug" along by the Earth so completely that we couldn't even detect *any* relative velocity (they couldn't fly experiments in space at that time) * Maxwell's equations were incomplete. Eventually it was found that the Aether drag, or whatever other effect was occuring, caused EM waves to exhibit what is known as the [Lorentz Transform](https://en.wikipedia.org/wiki/Lorentz_transformation). They found that if you took Maxwell's equations in one frame and modified them using the following 4 subsitutions: $t^\prime=\gamma(t-\frac{vx}{c^2})$ $x^\prime=\gamma(x-vt)$ $y^\prime=y$ $z^\prime=z$ Where $v$ is the relative velocity between this frame and the next frame in the x axis, you got numbers which lined up. This transform "fixed" the equations so that they matched the data. Science is good about that: always make sure your model matches the data, even if the data looks schizophrenic. Now I don't think you need to appreciate exactly what those equations are. What you have to appreciate is that they are messy. Physicists hate messy. Messy usually means we didn't understand the problem fully. This transform at least meant our physics wasn't provably wrong, but that doesn't mean the physicists had to like it. This transform has all sort of peculiarities. For example, we see time dilation and length contraction here, written right into the equations for $t^\prime$ and $x^\prime$. Also note that by twiddling with time, we broke simultaneity. Remember the story my physics teacher friend started with, with the train with flashing lights? It turns out that you and I can disagree on what *order* lights flash in, based on where we are standing. There may be some "proper time" order for the "correct" observer, but EM didn't provide any way to identify where that "correct" observer was. Einstein's brilliance was in the idea that *all* inertial reference frames were the "correct" one. He threw away the idea that simultaneity had any meaning at all, and started from the [principle of relativity](https://en.wikipedia.org/wiki/Principle_of_relativity): > > If a system of coordinates K is chosen so that, in relation to it, physical laws hold good in their simplest form, the same laws hold good in relation to any other system of coordinates K' moving in uniform translation relatively to K. > > > Okay, maybe Einstein's own words aren't quite so clear to the layman. Let's use a thought experiment with a train. If I'm on the train and you're on the ground, and the train is traveling at a constant speed with respect to the ground, then the laws governing the speed of light are equally valid in both my frame and your frame. I'm allowed to see that the speed of light is $c$ in all directions, and you are allowed to see that the speed of light is $c$ in all directions, even if I am the one holding the flashlight, while traveling really fast on the train. Sound messed up? Of course it does. Relativity is wierd! But what Einstein proved was that if you start from this principle of relativity, you naturally derive the Lorentz transform from that principle. The horribly ugly math of the Lorentz transform was still valid, but now it had a simple explaination: the laws of physics remain the same while changing frames. And indeed time dilation was a major factor in the cementing of relativity as "the right theory." Once we had clocks accurate enough to experiment with this, we found that, indeed, this kooky theory was right. Time was *not* absolute\*. Time could progress differently for different frames, and there was no global concept of simultaneity. So in your relativistic space ship, computers work just like normal, because in their frame, light is traveling at light speed, so electric waves can travel at 0.95c without breaking any speed limits. If those electrons were viewed from the ground, they would be seen as going at 0.9986c, which is faster, but still not faster than light speed. The stretching and contracting of our concepts of time and space would account for all the oddities that arise from that, and if you want to see the equation which you can use to calculate that 0.9986c, I recommend reading [el duderino's answer](https://worldbuilding.stackexchange.com/a/106536/2252), which is where I stole that number from. His answer also has the equation used to calculate that. So when you are doing relativistic spaceship thinking, always remember that *every* frame is a privileged frame for EM radiation. Light travels the same speed no matter what frame you are in, so you can always solve problems by simply picking the most convenient frame. In this case, it's the frame of the space ship. [Answer] Your question falls into a frame of reference fallacy category.. The electrons are travelling at 0.95 c in the ship's frame of reference. This is irrespective of whether the ship is stationary \*relative to whatever) or moving at any any velocity and it doesn't matter if it's moving backwards or forwards or even sideways. It will remain the same: the electrons are travelling at 0.95 c in the ship's frame of reference. To an external observer the ship can zip past at 0.95 c. OK, so that takes of the ship. Now granting the external observer some form of hand-waved, "magic" super-duper observing instrumentation to be able to observe what the electrons are doing. Will the external observer see the electrons are stationary? Absolutely not! The external observer will observe the moving at a higher relativistic velocity than 0.95 c. So the electrons in the computer will still be moving. However, it requires calculations passed on the sum of relativistic velocities. The electrons will be time dilated but the amount of time dilation will be determined in terms of their relative motion. The proposition the electrons are stationary in a moving ship only makes sense if the electrons were, for example, fired out of an electron gun at 0.95 c in the stationary frame of reference, which can be described as external to the ship itself, and the ship and the electron will be stationary relative to each other. However, the electrons running inside the computer on the ship will still be moving at 0.95 c in the ship's (internal) frame of reference. Note: the electron fired out of the electron gun is best considered to be outside the ship and the electron gun is at rest with respective to the ship which is moving away at 0.95 c in the electron gun's frame of reference. So from the ship's frame of reference, the electron gun is receding at 0.95 c Like most apparent contradictions of special relativity things go wrong, conceptually, when people mix up the wrong frames of references. This is definitely the case here. [Answer] I see a lot of (good) answers that all go into Relativity and its consequence, but none actually answers the question of the OP: > > Will humanity need to come up with a non-EM logic board to perform > course calculations for relativistic ships? > > > That answer to that is: Yes. And no - it is not physically possible to come up with something else that will work faster. The reason has nothing to do with relativity - as others have pointed out, the computer in your spaceship will work at normal speed from your perspective. But things in the universe will be coming towards you at a very fast speed. And you will only see them at the last moment because light only travels a little faster. So you will simply have a very short time to react. Let's take an example. Suppose you have good sensors/telescope and can detect small objects as far away as the Sun, that is, 8.5 light minutes away. And suppose you are traveling at 99% of light speed. From your perspective, that means that these objects are traveling towards you at 99% of light speed. And due to relativistic length contraction, they are actually not 8.5 light minutes away, but more like 1.2 minutes. So the light of these objects takes 1.2 minutes to reach you, but the objects themselves take only 1.212 minutes to reach you. Therefore, your reaction time must be better than 0.73 seconds. And this is inclusive the time it takes to move the ship out of the way... To add to that, you would *want* to get out of the way as well, because the objects will have enormous kinetic energy. If I calculated it correctly, a 1 gram object will hit with approximately the energy of an atomic bomb. [Answer] # Your ship runs fine Everything on board your ship operates exactly as it always does; there is absolutely nothing out of the ordinary going on. You don't even look that unusual to the people you pass by. Despite the popular description, time dilation isn't really that "things slow down". Instead, time dilation is about the fact that when people take divergent trips and then meet back up, their watches don't agree. Time dilation is an obstacle to synchronizing distant clocks. The usual idea of time dilation is really about a single POV deciding upon a *convention* for a universal time standard (there is no *physical* basis for such a standard). If they are sufficiently inertial, then *by this specific standard*, that person's clocks will run faster than anyone else's. But any other person can establish the same convention with *them* at the center instead, and (if they're sufficiently inertial) it's *their* clocks that run the fastest. --- The better way to think about the situation is simply that the trip will go by more quickly. A human sitting on Earth has to wait 8.5 years for a light signal to make a round trip from Earth to Proxima Centauri and back, but a space traveler travelling at 0.95c (as measured by the people on Earth as you leave and return) will make the round trip in merely 2.7 years, as measured by their own clock. A noticeable difference in elapsed time to be sure, but it's not even an order of magnitude in effect. [Answer] The idea of a course corrections at the speed of light is the point of failure, not the computer which is "handling it". Once your ship is proceeding forward at the speed of light, the light which it is receiving from "up ahead" will be too old to be relevant. For example, a particle of dust which becomes visible at a distance of one light second will hit the ship one half second after it is first seen. The light which reflected off of it as it first came into sensor range will meet the incoming ship midway through its one light second perimeter. Even if the computer decides instantaneously to evade the particle, that still leaves no useful time for evasion. We will have to bully our way across space once we reach light speed and beyond. Captains screaming "Correct Course" or "Evasive maneuvers" will be quaint misconceptions from the scifi of our distant past. [Answer] Why work so much, when you can just make a nice, fast computer with quantum entanglement? If your story characters can manage 0.95c, that should be a lot easier. However, to answer your question, for you, the computer will work JUST fine. You will detect no change in the computing speed. However, for someone outside, the computer will appear to move a lot slower. [Answer] I think that once spaceships get going that fast, better computers will be in place. Supercooled superconductors, or maybe room temperature superconductors, or maybe just light being conducted, will allow calculations to be done at the speed of light. So electrons in copper is perhaps not the right way to be thinking of this. [Answer] Yes. Work this problem backward with a simpler example. Let's say your computer is a ramp with a marble that hits the stop button. You start going the speed of light with the marble going down the ramp and without external influence you will never stop. I like to think of momentum at relativistic speeds as a energy parasite. Not chemical energy so things freeze. All energy so things stop. External influence is important here because that's the only way you will stop or turn. An external EM source will be needed to shut down your engines. Dialing this back to 0.95c makes it so you don't need to collide with some radio single that originated from somewhere besides your ship. Your computer will be very slow but space is very big so you'll have time. Just be ready to slam on the breaks when that planet starts getting bigger. Edits based on feedback: Example 1: If an Earth based turret and a ship based turret going 0.95c start targeting each other at the same time the earth base one would shoot first. The computer at relativistic speeds has a clock that ticks slower so it calculates slower so it fires the lasers later. If Earth and the ship are close enough together Earth could hit the ship before the ship fires and the ship would think "Oh my god how did they target us so fast". Example 2: Your 0.95c ship buzzes a planet and asks them to do a calculation. The planet will do the calculation faster than the ship thinks possible. Or the reverse might happen - "Sir they haven't responded to the order. Oh they are still decryption the message." ]

[Question] [ What is the layout (or physical arrangement) of a shantytown made of storage containers? It is meant to be chaotic, but are there *any* organizing principles I should be aware of? [](https://i.stack.imgur.com/NCjba.jpg) The cargo containers are different sizes and designs of intermodal space shipping containers: so probably long and thin, stackable. It is more diaspora slum than bohemian chic, containers are cut and modified, and other materials fill-in the gaps or create extensions. I'm guessing it was a harbor freight yard originally (or near one), but this town has been here a while (decades), and they've had (at least intermittently) the ability to hire machinery to move the containers around. The overall "footprint" of the town is constrained, so it stacks upward probably 5 or 6 containers high (a typical container can be split into 2 levels). I am not worried about the composition of the boxes or the "walls", that is intended to be chaotic. But would there be any organization to the shanty town itself? I am ignorant how a town like this "happens", if there is a power structure or it is collectively spontaneous. I assume there's an evolution from squatting in empty containers to re-arranging a town. Is everyone just doing their own thing? Can I buy a container and plop it on someone else's container? There must be some rules. * Who is in charge? Is there a landlord? A collective government? Is everyone squatting? * Are there public areas? a wider "street" or plaza? Or is it just a residential rat maze to maximize living space? * Is it enclosed with only a few "gates", or is it porous with anyone coming and going? Since I don't know how this evolves in real life, I don't understand the goals and needs of the people doing it, or how they might plan and organize their environment. [Answer] Let's take a look at [Kowloon Walled City](https://en.wikipedia.org/wiki/Kowloon_Walled_City) - closest real world analog of what you're asking. # Government There used to be somewhat competing gangs. There was, generally, a truce between them, and people who didn't belong to any gang was generally left alone. No taxes, no police. Small troubles were your troubles, big troubles were dealt with by the gang. Was there someone on top? Probably not, but even if there was, he was not interfering. Rumor says that [Triads](https://en.wikipedia.org/wiki/Triad_(organized_crime)) were in charge at the top. # Citizenship Generally if you were able to build a living area for yourself, without making anything to collapse, it was yours. If you bought, were given or inherited a place, it was yours. If someone was trying to kick you out, see "big troublemakers". Gangs built "modular settlements" for their workers and for regular people any settlement needs: cooks, seamstress, cleaners, all that stuff you need to run opium den, brothel or illegal casino. Most of people weren't involved in any criminal activity - at least not knowingly and directly. You mop the floor and don't care if it's just a drink bar or brothel's front desk, things like that. # Public spaces Kinda: [](https://en.wikipedia.org/wiki/File:KowloonWalledCityAlley2.jpg) This was pretty much all you got. A tiny bit of sunlight. Normal alleys were much more like this: [](https://en.wikipedia.org/wiki/File:KWC_-_Alley.jpg) There were *some* exceptions: > > The yamen in the heart of the City was also a major social centre, a place for residents to talk, have tea or watch television, and to take classes such as calligraphy. The Old People's Centre also held religious meetings for Christians and others. Other religious institutions included the Fuk Tak and Tin Hau temples, which were used for a combination of Buddhist, Taoist, and animist practices. > > > But that was pretty much it. # Architecture > > The City's dozens of alleyways were often only 1–2 m (3.3–6.6 ft) wide, and had poor lighting and drainage. An informal network of staircases and passageways also formed on upper levels, which was so extensive that one could travel north to south through the entire City without ever touching solid ground. Construction in the City went unregulated, and most of the roughly 350 buildings were built with poor foundations and few or no utilities. Because apartments were so small — a typical unit was 23 m2 (250 sq ft) — space was maximised with wider upper floors, caged balconies, and rooftop additions. Roofs in the City were full of television antennae, clothes lines, water tanks, and rubbish, and could be crossed using a series of ladders. > > > No reason to think that your city would be different. # **Why?** This is the big point. Kowloon emerged because it was free. Free from governments, free from regulations, free from taxes and police force. Building a place for someone was relatively cheap. Gangs were earning money and were glad to use people who wanted to run from highly regulated societies. # Could it have been built with storage containers? If you look thorough the photos, you probably will agree with me that some parts of it probably was. Modularity was a thing, that's sure. Containers has some stacking limit and possibly Kowloon wouldn't be as high if built mainly with them, but they are readily available, so might make construction cheaper. Anyway, after some times lines would start to blur - just like it happened with Kowloon. [Answer] There's a difference between the trendy places that make an apartment building out of shipping containers (which is what you have as your picture) and actual slums. [](https://i.stack.imgur.com/quFat.jpg) While there were patents for shipping container living as far back as the 1960s, the first place to do it where it was widely documented was Armenia in the 1980s after an earthquake. > > many of these ramshackle Armenian shipping container homes, which they call “domiks,” are still occupied by people who never got back on their feet after the quake, even though most of the containers have become rusted and leaky, and are located on public lands. A few years later, during the Persian Gulf War, the US military used shipping containers as bomb shelters and mobile prisons, and the idea spread from there. By 1998, Simon’s Town School in South Africa had built its new school building from 40 shipping containers at a cost of only $227,000. [SOURCE](https://urbanscrawldc.blog/2016/10/13/who-invented-the-shipping-container-home/) > > > How it happens organically sometimes is this: disaster strikes, and people send supplies to help. They send it in shipping containers. Instead of sending them back, the people keep them to live in because they have no homes and they are better than tents. They are then stacked on public land, land no one really claims or a donated area. Or it could be because of war--in which case they will start as a refugee camp, with a mix of tents and containers--and in this case, yes, it will be orderly, with stairs and everything, rather than rope ladders or something rickety. [](https://i.stack.imgur.com/mF7NR.png) As to structure--it depends. Are they actually doing paperwork? Or is this a slum? Because they are unlikely to even be wired up correctly if at all. Take a look at this solution to lighting in [the Philippines](https://www.youtube.com/watch?v=kDL52lTri5c) Know as well that the pictures I have provided are relatively new. There are disadvantages to container living (it's a hotbox with no ventilation or light), like rusting and people actually tend to use them as a base to build other, wooden structures on top of. Also, a flat roof is not a good thing, so in places where they've been there a while they tend to add a slanted roof with corrugated tin. > > Who is in charge? Is there a landlord? A collective government? Is everyone squatting? > > > Who is in charge depends on the government and if it's a slum or something trendy or just a cheap way for the government to build housing. Same answer to landlord. They could all be squatting, or not, as you please. It's your world and your neighborhood. > > Are there public areas? a wider "street" or plaza? Or is it just a residential rat maze to maximize living space? > > > Again, this depends on how and why it was built and where the containers came from. > > Is it enclosed with only a few "gates", or is it porous with anyone coming and going? > > > This implies planning. This is really going to depend on what people need. They'll do what works. I would research [Hoovervilles](http://www.history.com/topics/hoovervilles). No two were alike. They grew out of the Great Depression. Do look at the link above. Below is a useful snippet of that article. > > Most Hoovervilles operated in an informal, unorganized way, but the bigger ones would sometimes put forward spokespersons to serve as a liaison between the camp and the larger community. St. Louis’ Hooverville, built in 1930, had its own unofficial mayor, churches and social institutions. This Hooverville thrived because it was funded by private donations. It maintained itself as a free-standing community until 1936, when it was razed. > > > You've got to look closely at WHY and HOW your community of containers was built before you can determine what it actually looks like. That's up to you, you need to do what makes sense in the context of your story. So, you know, they could be hipster housing and look like this: [](https://i.stack.imgur.com/tYXi6.jpg) [Answer] Tangentially I lived in the equivalent of a 20' ISO shipping container when I was deployed to Bosnia in the early 2000's. The thing was called a Coremek if I remember correctly, and the military used them because they were relatively cheap, modular and could be used to build up living spaces with relatively simple engineering resources. Corimeks had the same attachment points and lifting points as an ISO container, so the same sorts of forklifts and crane equipment used for shipping containers easily translated to moving the shelters around as well. Of course this wasn't as simple as just piling the containers on top of each other, a steel framework was built and the Corimeks were stacked inside the framework. The framework also took the structural loads of the weight of the shelters and people, supported walkways and stairs, and also provided conduits for power cables and so on. [](https://i.stack.imgur.com/kLf3r.jpg) *The Banja Luka "Metal Factory". You can see examples of how the shelters are assembled in a metal framework to make "apartment blocks"* This demonstrates that using ISO containers for shelter can be taken to a higher level, but this also involves organization, planning and resources (in this case of the military) to assemble the materials and build the into large blocks of residencies. This is unlikely to happen spontaneously in a shantytown (and also leads to the question of who is moving the ISO containers around, you need some heavy machinery to do so), and ISO containers are not pre wired, nor have doors and windows properly fitted to them. The work around is that once a military base built this way has been decommissioned, it may be cheaper and simpler to sell off the property without dismantling the shelter blocks built out of pre made containers. Then the characters will have essentially abandoned apartment buildings to move into. [Answer] ## The paradox Stacking shipping containers requires large equipment. Shantytowns by definition are organicly grown without central oversight. These things are add odds with each other. If you want a shantytown to form with shipping containers you'll likely find indivudual people cutting and ripping pieces of the existing containers and take them to their home. They lack the equipment to take them as a whole. So you'll end up with something ramshacle that happens to use parts of shipping containers. I also doubt that could support multistore constructions. If you want that you gotta approach this differently. To have a shantydown develop upwards you need not only limited space but also support. ## Used to be different So you don't start this as a shantytown. If we're stranded near a shipping yard. Let the survivors control the equipment there to build themselves a home out of shipping containers. This will be your primitive downtown area. Now over time either more people showed up or the population boomed. Either way new housing was needed. People started to build, filling the ground first. Existing higher floors added some extra rooms and balconies. Then things started to merge. People ran out of room. ## The rest Now for your sub questions. Nobody is on charge. This isn't an organized event. People get stranded here, decided they need shelter. They don't seek permission. If the local government wants them gone they'd be gone. As long as it would be enformed. Words mean nothing to these people. Therefor there also no public buildings or facilities. No plumbing, power is also highly unlikely. This also means the edges are at least porous if not ill defined. The more people come the bigger it just grows. In whatever direction is the easiest. Now there could be a leadership but not one that build the town. No this leadership would arise after the fact. Likely has a strong criminal presence if not at least deeply corrupt. Think of gang leaders who want some semblance of order around them. Maybe a local business man who didn't flee the moment his economics improved. Maybe someone who controls infrastructure like clean water or power. [Answer] There is always a logic to how towns are organized. Oftentimes the logic is mostly convenience or inertia. If there are existing stacks of shipping containers for instance people are probably going to rig up walkways for easy access. Once human traffic has work a path, other people are probably going to build alongside instead of disrupting the flow of traffic. Shantytowns tend to occur where there is a lack of a conventional authority. Without that building codes go out the window. Houses will be built cheaply out of whatever is available. People still have needs and ideas of personal property. Once I've built my house I'm going to be righteously pissed if you want to plop a shipping container on top of it. There tends not to be a centralized governmental authority, and if there is it's probably looking the other way. There may be enterprising individuals who own property and lease it to whomever is willing to pay. The odds are high that organized crime is also involved. [Answer] As AlexP mentioned containers have a standard height: 8.5 feet tall. Containers also have a standard width (8 foot) so they can be placed on wheel chassis for towing and to make stacking on ships easier. There are different lengths but most of them are 40 foot long. Again, for easier stacking. Here is the [ISO Standards page](http://containersolutions.net/specifications/) for shipping containers. Places like China find it cheaper to make new containers than to have them shipped back. So, places with a lot of imports tend to build up containers. Here's an article by [someone who doesn't like the idea of shipping container housing](http://www.treehugger.com/sustainable-product-design/whats-wrong-shipping-container-housing-one-architect-says-everything.html). There are some useful tidbits like: > > **Structure.** You’ve seen the proposals with cantilevers everywhere. > Containers stacked like Lego building blocks, or with one layer > perpendicular to the next. Architects love stuff like this, just like > they throw around usually misleading/meaningless phrases like “kit of > parts.” Guess what- the second you don’t stack the containers on their > corners, the structure that is built into the containers needs to be > duplicated with heavy steel reinforcing. The rails at the top and the > roof of the container are not structural at all (the roof of a > container is light gauge steel, and will dent easily if you step on > it). If you cut openings in the container walls, the entire structure > starts to deflect and needs to be reinforced because the corrugated > sides act like the flange of beam and once big pieces are removed, the > beam stops working. All of this steel reinforcing is very expensive, > and it’s the only way you can build a “double-wide.” > > > He also has some links in there. The good news is that you can stack them 9 high. As far as the social issues, it really depends on what kind of city it is. If the government didn't build it then I'd say that an importer either set up the structure or sold the container to whoever set up the structure. Unlike a shanty town like the one around Mexico City that it built out of found goods by the residents, containers need a truck and a crane to place them. So, someone has to expend resources to build it. They will want to receive some kind of benefit. [Answer] Like another answer, this is kind of a comment but not necessarily a full answer In Shantytowns, they usually happen organically. They are usually built out of whatever is readily available, and there is not a lot of attention paid to planning. When you bring in cargo containers, you might run into a few problems. Inter modal containers are HEAVY. You would need a method of dragging one out to the site, and that would require a fairly large truck, at the least. The truck would need room to maneuver in order to place the container. That's the first problem, but that's not insurmountable. I worked at a place that made frequent use of these containers, and the delivery truck would pull in, jack the bed up and slide the container gently off onto the ground, lengthwise. This could work for a shanty town that is only one level high. The next problem is that you need serious heavy equipment to stack the containers. The kind of forklift needed to lift these things is enormous. Not only do you need a huge forklift, the ground needs to be stable enough to support the weight of the forklift. Finally, if you don't have a forklift, you would need a crane. Again, this is non-trivial infrastructure that would not likely be in a shanty-town. Finally, in the example picture, the containers are not neatly stacked. The problem there is that the containers strength is primarily on the corners and along the edges. Yeah, you can stack them several high, but you have to be pretty precise. Also, cutouts for doors and windows weakens the structure, so the random looking stack would be impractical. I would suspect that the social organization of the shanty town would be fairly chaotic. Overall leadership would likely be in the hands of organized crime. This, in your case, might actually be beneficial. A Mob Boss might have the incentive to expand the shanty town, as more people mean more customers and more power. A Mob Boss might gain control of a construction or shipping company, for money laundering, making access to the necessary heavy equipment possible. At this point, the growth of your shanty town would be organized for the Mob Boss's convenience. [Answer] All previous answers are very real-world-inspired, but I notice that you did not add the "hard-science" tag. Let me encourage you to do your own thing here. I see a large, sprawling, chaotic, convoluted mess of living cubicles. Loads of small stairs, ladders, ropes, swings and so on. Roof-tops which lend themselves for wild hunts, Matrix/James Bond style. Little surprisingly calm inner courtyards with maybe even a tree or two. Wild communications and electric poles with lines going wherever the residents needed them. Children who have grown up in there and know every single corner, getting out of danger in the blink of an eye. A deep sociological-political structure. And so on. You can and should answer your questions yourself (just pick an answer if you cannot decide)... all alternatives you listed seem possible and plausible to me. The book Ready Player One features a shanty town exactly like what you're asking for; it's a good read even if the chapter on that town is rather limited in length. [Answer] I started to write this in response to this [comment](https://worldbuilding.stackexchange.com/questions/75818/is-there-any-organization-to-a-shantytown-of-storage-containers#comment221310_75822), but it got too long, so I am doing a quasi answer instead... You made a comment about not changing the shapes or composition of your containers too much. I wanted to point out that you should not bind yourself too closely to the idea that your futuristic shipping containers will share significant traits with the ones we currently use. Keep in mind that our current containers are built the way they are as a result of their primary purpose. They are a certain width because we need them to fit on trucks and rail cars. They are built to stack on each other because it makes them more effective for ocean shipments. Their walls and roof are made from comparatively light weight materials because their primary purpose is to keep things contained and sheltered from the elements. By comparison the containers used in air shipping are very different both in terms of shape and material. They are designed with odd shapes in order to better fit the curvature of the air frame. They do not have the reinforced corners for stacking because they never get stacked that way. Many of them do not even have solid closures, using canvas or nets to keep things contained, because they are rarely if ever exposed to the elements. If the containers from your story are primarily left over from space shipping they are going to have even more differences. Here are just some of the questions that could significantly influence the design considerations of such containers. Did the goods needing to be shipped need to be protected from vacuum? Were they loaded inside a ship? Or just strapped onto an interplanetary/interstellar "tugboat"? Are they still made from current day materials? Or was a cheaper/stronger composite developed? What types of forces do they have to withstand? Acceleration? Gravity? Radiation? How do they renter atmosphere and land? Do they just cut them loose and let them fall with a chute or bounce system to reduce impact? Or are they brought in under power? Assuming improved materials science, how well do they stand up to weather and steady gravity? Keep in mind that any feature that increases the complexity or cost of the container greatly reduces the potential for them to be left lying empty for people to repurpose in this way. Also the cost of transporting mass out of a gravity well and across interplanetary/interstellar distances should be considered as well. Every gram of container material needed is one less gram of paying freight we can carry. [Answer] Assuming your alien containers are similar to earth containers and built out of the same kind of design principles you have a few constraints. Storage containers have attachment points at the corners where they can be linked, this means they will be jointed at mostly 0 or 90 degree angles, lengths vary but are still standardized so you may be able to create empty spaces by varying length or attaching at 90 degrees. The more space is limited the more encouragement there will be to join all the containers together and not waste space scattering them around. There are a wide variety of doors in containers and many specialty containers designed to ship special goods, such as liquids, animals, or pipe, this plus of course broken or modified containers give your people many options. There is also a wide selection of roof extensions, wheels, ladders and other attachments available, some of which sould easily make it into your shanty town. Maybe a few liquid tanks have been turned into rain catches, or a half buried insulated container has been turned into a kind of root cellar. Shipyards are also on the coast so maybe the town is built on the tidal flats and the lowest level actually gets submerged. Maybe the shanty town grew around a huge cargo barge that ran aground during a storm, The cargo and containers were abandoned becasue it was too much trouble to retrieve, this would draw a shanty town quite quickly just for the supplies. Of course you have whatever might have been the contents of the containers, Shipyards often have unclaimed but full containers. Maybe one was nothing but Yellow mylar tarps so they are all over the town leading it to be called yellowtown, or one was full of children's building blocks so the locals have many things made of these blocks. The possibilities are endless. Maybe that's how they got the ability to move the containers, one of them had an electric forklift/hoverlift inside and they were able to use and keep running through jury rigging for many years. there is also quite a lot of shipping container architecture already out there you can draw inspiration from. And of course actually shipping container shanty towns do exist in places like Pudong. ]

[Question] [ There are many application of being able to communicate with the dead but in the interests of scoping I'm interested in law enforcement and sentencing. The method would be scientifically proven communication and no trick or belief required however they would be human... the dead would be just as error prone and fallible as we are! Assume: * The service requires a skilled professional (who most often work for the courts) however once summoned the dead person addresses the room, everyone hears/can talk to them. * The dead know everything they knew at the point of their passing plus what they've been told since * The dead do not know (or are unwilling to share) information about what happens between visits. In effect they only remember what happens in the living world * The dead cannot observe or interact the living world, they can communicate only through these conversations * You can only communicate through sound, you can't see each other * You can communicate with anyone, however a dead person can only speak to one person at once * The dead person can only be summoned if they wish to be, they can also leave at any time (no holding the dead hostage!) Obviously this would be valuable for people dealing with grief but I'm interested in it's application in law enforcement. What policies of policing and courts would be different if the dead could be contacted? [Answer] Several ideas what would be different: **Better murder cases**: You can ask a person who did murder them. And possibly you could use it as evidence in court **Different inheritance rules** You can summon recently deceased person and ask them who should get what. And obviously, you could make sure the deceased person can decide about conditions (like: You get my house, but finish college first!) **Espionage level 2.0**: Right now, if you send spy to get some info, and such spy is killed in action, you do not get any info about mission whatsoever. But, if your spy is killed, you can get at least some info. It also means that if you catch a spy, you keep them alive as long as possible to protect your data **Elvis, where are you?** You know the cases of "that person is really not dead!" Now you know for sure if given person is dead or alive. Could be used not only for Elvis, but generally for everyone who gets missing. If their summoning from dead fails, you know they are alive and you should try as hard as possible to find them. Once you succeed, you (sadly) know that person is dead and ask them where their body lies **I will sacrifice self so you can live**: See above. If group of people gets missing, good survival strategy would be to sacrifice one to let everyone else survive. (better with one dead than everyone dead). And in your "law enforcement" setup, you have to decide, if basically "killing" someone to save everyone is ok or not. **I see dead people. Not** Do not forget about black market and impostors. Assume nowadays setup when if you approach medium able to talk with dead, you do not know it is for real, or if its just a play. Even in your setup such people would exist (claim to be trained, but not be trained at all). How would common person decide if they speak with really trained person, or fake? And would it be a crime to pretend that I can speak to dead? *EDIT of this paragraph:* Even after editing it to make sure that everyone can hear the person, once they are summoned, there is still room for fakery (hidden radio and voice actor is one from top of my head) But, in law enforcement there is one biggest flaw: **I am dead. And I lie. So what?** Imagine I am dead now. Someone summons me because of inheritance. And I tell such person, that I won the lottery (huge bulk of money) and the pile of money is stored in specific destination. But, twist, none of it is true. How do you know I am liar or not? And take instance of murder. I have been murdered by John Doe. But I hate Thomas Unknown. What happens if I say that I have been murdered by Thomas Unknown? How do you punish me for a lie? I am dead. So what *worse* can happen to me? **EDIT** One more idea: **Public domain? NEVER!** Imagine I am popular author. And I die because of age. Someone can summon me and I can help that person to finish my "last" novel. Who is actually author of such novel? And, how do you decide what work is public domain and what is not? And what prevents me to write *yet another novel*? [Answer] In the courts, all that mechanically changes is that dead people become witnesses. However... I feel that they might not make for reliable witnesses. (SPOILERS: Phoenix Wright: Ace Attorney) In Phoenix Wright: Ace Attorney, the [DL-6](http://www.court-records.net/DL-6.htm) case is a case in which a spirit medium is used to communicate with the dead, as to find out who the murderer is. Relevant excerpts: > > On December 28th, 2001, Miles Edgeworth went with his father, Gregory Edgeworth, to the courthouse. Gregory Edgeworth had a trial against Manfred von Karma, a veteran prosecutor who hadn't lost a case in his long career. During the course of the trial Gregory managed to prove that Karma had tampered with evidence, giving him his first penalty in court. > > > After the proceedings, Gregory, Miles, and a court bailiff named Yanni Yogi left court and entered an elevator. Almost immediately afterwards there was an earthquake and the building lost power. The three remained trapped in the elevator for several hours with little oxygen. Yanni began to panic, and an argument broke out between him and Gregory. During the struggle that ensued Yanni's pistol came loose from his belt. Desperate to stop their fighting, young Miles took the gun and threw it at the pair. It fired once, and all three in the elevator finally lost consciousness. > > > The power then came on, and the elevator doors finally opened. Inside, Gregory, Miles, and Yanni were all unconscious, and lying next to them was Yanni's pistol. **Already furious with Gregory for his failed reputation and under the shock of having just been shot, Karma snatched up the gun and shot Gregory in the heart, killing him instantly.** He then left the scene. > > > The police investigated the murder, without finding any trace of the first bullet fired from Yanni's gun. But the second was a perfect match to Yanni's weapon, and he was charged with the murder. Even that, however, wasn't enough to convict him, and so the police turned to spiritualist Misty Fey (mother to Mia and Maya Fey). **She summoned the ghost of Gregory Edgeworth to testify as to the events.** > > > **Whether or not Gregory really understood how he had died that afternoon, he was quick to place the blame on Yanni.** Through Misty, he claimed that Yanni shot him during their struggle. Miles testified to the same. But Yanni's lawyer, Robert Hammond (employed by the Grossberg & Co. Law Offices at the time) coerced his client into pleading temporary insanity. By placing the blame on panic and oxygen deprivation Yanni was able to earn an acquittal and was set free. > > > Misty Fey's reputation as a spiritualist was ruined. Because the testimony she had "summoned" from Gregory Edgeworth failed to hold up in court, she was considered a fraud and a fake. > > > The reason Gregory here gives false testimony is because when he passed out, he was in a sealed elevator. No one else could get in. There were two other people in the room. His son, Miles, and some bailiff, Yanni. He had had an argument with Yanni. He passed out afterwards. Surely he didn't kill himself. He had heard only one shot, and that was when his son threw the gun. He believes his son killed him, by accident. But he doesn't wish to indict his son. And Yanni was hostile to him anyway. So why not blame Yanni? --- This is what I believe to be a relevant example for your world. People may mistake events that happen. I believe that people will have trouble recalling the moment of their death because it is a strange state to be in (dying, as the brain will start to conjure up things that aren't there due to lack of resources), and that their testimony simply isn't solid evidence. It's practically the same as a witness who was in a state of delirium. The impact of this varies on how your medium/spirit summoning enters the world. If spirit mediums are recently new, expect courts to have suspicions of using the method. Expect people to express distrust. If they're public knowledge and have been around for a long time, however, expect killings to be done differently. Murdering someone is something you have to do without exposing yourself to your victim. Murderers result from things like domestic violence or disputes gone bad are likely to be solved via testimony of the deceased, but assassinations or sudden deaths (hit-and-run?) are not. It's not going to solve all cases. It's also not definitive evidence. I also wonder how you're going to deal with perjury - what if someone who is dead lies? [Answer] Since they retain any human motivation they had when they were living, and can lie, I would think their use in law enforcement would be extremely limited. The police might use them to aid in an investigation, like questioning a witness. But they'd be less useful than a witness because a witness can be called into court and threatened with perjury, or complicency in a crime if they don't cooperate or tell the truth. A dead person is not susceptible to such threats, so has much less motivation to "snitch" on a fellow cohort, and more motivation to frame an unliked ex-spouse. [Answer] One thing that is worth mentioning is that kidnapping would be a lot more common than murder all of a sudden. It's no longer possible to shut someone up by killing them, so organised crime would move more towards a kidnapping and slavery approach and holding people hostages than the more traditional "sleeping with the fishes". So you might find that in this world, human trafficing would be a lot more common. People would attempt suicide just to notify someone that its going on, so I imagine that there would be a greater emphasis on keeping people alive within this trade. Also, speaking to dead people frequently would most likely end up taking a massive toll on the mental health of the law enforcers, so time off due to stress would be more common. If you DID need to kill someone, it would probably be common to try and damage the persons brain in a way that makes them unable to recall who did it. The invention of memory wiping devices may have become a common black market item if you decided to go down that route - if not, would a brain damaged person come back as a brain damaged ghost, or would they return fully coherent? What if you cut out their tongue before hand? It's also worth noting that the dead may have there own reasons to not divulge information on how they died. Still living family members might have been threatened before they died, giving them a reason not to testify. Terminally ill people may well end up commiting a large portions of serious crime as they basically have nothing to lose, and can guarantee that any proceeds from their crimes actually end up going to their family. [Answer] I read a book once, [*Blue Limbo* by Terence Green](http://rads.stackoverflow.com/amzn/click/160450434X) that played around with a similar dynamic. In the book, blue limbo is strictly a way of keeping people alive that would be considered clinically dead with modern technology. Essentially, if doctors can get to the deceased's body within a few minutes after death, a machine can keep the brain alive independent of its body and allow communication through a text-only blue-colored terminal. This blue limbo isn't full consciousness, so many of the deceased's potential motives the other posters have mentioned wouldn't necessarily apply. This style of temporary resurrection automatically ensures many of the qualities you wanted (requires a skilled professional, limited communication, dead can still form memories), but is also limited in time to the very recently deceased. It's been several years since I read the book, but I remember blue limbo being used as an important plot device in a murder investigation and a substantially different legal system. The deceased's memories leading up to the murder returned slowly, giving investigators conflicting details and leading to a bit of a witch hunt. That's about all I remember. [Answer] For law enforcement, I don't think it would make much difference. It'd probably be a good source of witnesses for murders, but people would just start shooting each other in the back, and nothing would change fundamentally. The courts would be a different story, because it affects some of the founding assumptions of law and ethics. There'd be loads of loopholes from the way laws are currently worded, but even apart from that you could imagine any number of debates about whether ghost testimony is hearsay, whether it's fair to allow witnesses who don't fear perjuring themselves, how it affects the rights of the living etc. I'd expect cases involving the dead to be automatically longer and more expensive, and quite plausibly their testimony would be simply inadmissible. That might be interesting for a police story, because murder cops would often know who did it, but need to find independent evidence. [Answer] Your world may have ethical issues regarding necromancy. Does your society believe people have an inalienable right to rest in peace? Can police use it whenever they want, or do they warrant to obtain necromantic testimony? Also, depending upon your society, it could be a traumatic experience for the living to face the dead. This could allow for some nasty threats by a prosecuting attorney to coerce defendants into accepting a plea bargain. Or conversely, defense attorneys could use it as a threat to get people to drop charges. ]

[Question] [ **Closed**. This question needs to be more [focused](/help/closed-questions). It is not currently accepting answers. --- **Want to improve this question?** Update the question so it focuses on one problem only by [editing this post](/posts/824/edit). Closed 9 years ago. [Improve this question](/posts/824/edit) When building any fictional world, perhaps especially a fantasy world, the whole question of religion is bound to come up. What are the gods? What do people believe in? How and where and why do they worship? And what effects or implications will that have? Then there are the sub-questions, such as: * What if miracles really work? * What if the gods show up sometimes? * How do magic and religion intersect? * Can there be religion and really advanced science at the same time? In short, **what are the fundamental elements of religion, and how should I go about constructing them coherently and plausibly as I design a religion for a culture in my world?** [Answer] There are a number of preconceptions that need to be cleared away in order to get at a useful answer. 1. Religion is not reducible to faith, belief, ethics, or philosophy. 2. Religion does not necessarily have anything to do with "gods" in whatever sense. 3. "Miracle" is an extremely narrow and specific type of event that is properly limited to Christianity (though arguably also to Judaism and/or Islam); it is again not generalizable. 4. "Magic" is a well-nigh impossible category, even worse than "religion," and as such there's no way to make blanket assertions about their intersections. 5. The "war between science and religion" is a 19th-century invention, principally American; there is no intrinsic conflict. 6. There is no generally-accepted scholarly definition of religion, nor is it likely that there ever will be. Once you accept these points, which are broadly accepted by professional scholars of religion (which is very different from "religious scholars" or "theologians"), the question of "designing a religion" changes dramatically. One can hardly give a "right" answer to this, but there are some general guideposts worth considering by way of preliminaries. **Religion is universal** Any of the various semi-functional definitions of religion references a set of phenomena that appear to exist and have existed among all human societies in all places and times. We do not know of strong counter-examples. This has a number of interesting implications: 1. A society truly without religion is deep in fantasy territory, arguably harder to imagine and formulate than extraterrestrial alien societies. 2. Religion is not intrinsically bound up with technology, science, etc., but at the same time it is not intrinsically distinct from these things either. 3. Religious phenomena tend to be recognizable to one's neighbors. Albeit the category "religion" as we know it is a sixteenth-century European invention, some of the most ancient extant texts already reference neighboring peoples as having gods, temples, sacrifices, and so forth, in some cases (notably Egyptian ones) offering translations: "Among the Greeks, Isis is usually known as Aphrodite, and is offered the following sacrifices...." **Religion is ordinary** Most of the phenomena we think of as "religious" are embedded in everyday life and concerns. Fertility, health, death, marriage, hunting, crops, and so forth tend to get a lot of attention in religious systems. This runs contrary to an old (but utterly false) notion that religion is about explaining or accounting for the extraordinary, i.e., the old wheeze that religion comes about because people see lightning and get scared or whatever. On the contrary, religious expressions, when they can be called explanations or accounts in the first place, tend to provide explanations and origins for the utterly ordinary: why do humans eat animals? why do humans excrete? why don't we have three buttocks? **Religion is not falsifiable** Religious systems do not necessarily make any claims that could be tested in any way whatever. When they do make such claims, they tend to be accurate within reasonable limits, e.g., claims about the natural world and its various phenomena. (The *causes* attributed to these phenomena are likely at variance with modern scientific explanations, but the phenomena described are usually accurate enough, and sometimes stunningly so.) The usual supposition is that any falsifiable and totally false claim will tend to die out over time, because it becomes obvious to everyone that it's false. On the other hand, bear in mind that "correlation does not imply causation" is a logical principle that most people simply do not seem to grasp, and that a claim based on its reversal is not likely to be easily falsifiable. (E.g., "the sun comes up every morning because we sacrifice to the gods every night" isn't falsifiable, since nobody's going to just stop doing all sacrifices to find out, and even if you did one could always suppose that the next tribe over did their sacrifices, QED.) **Religion is not intrinsically about explanation or fear** This is a very old theory, of course, but it doesn't seem to work in the real world. The overwhelming majority of extant etiological myths (myths about where something came from) do not provide an "explanation" in any kind of straightforward sense. Natural phenomena that are genuinely terrifying to a given people may well have little direct representation in their myths or rituals. While one can certainly argue that religious behaviors do in some sense provide some people with some kind of psychological support with respect to some sorts of insecurities, that's so broad as to be useless (and in no sense exclusive to religious phenomena however defined). **So... how do you go about designing a religion?** Let's think about this as a process rather than a checklist. In all likelihood, you already have some vague notions about what you want, so write those down. Probably this is stuff about gods and whatnot, perhaps a creation myth or something. The next step, however, needs to be about **ordinary people in their ordinary lives**. If in some way these gods are important to these people, what is it that the latter do? Why? The answer does not have to be "worship." That doesn't really mean anything much. Think about the gods as people for a minute, however strange and powerful. If I'm an ordinary male person, is my relationship with a given god akin to that I have with my friend? my brother? my father? my chief or king? my wife? my lover? Does my wife have the same kind of relationship, and is it to the same god? (Gods don't have to have consistent sexes, you know.) Do I get involved with more than one god? Perhaps, for example, I talk to my personal or family god in a chatty sort of way every few days when I am alone, kind of keeping him up to date on my life. I don't really expect a lot from him, and he doesn't expect a lot from me, but we're sort of buddies. I gather that my wife and the other ladies have quite a different way of relating to a singular goddess, but that's female mysteries and I don't really want to know -- I'm sure it's icky, since my impression is that a lot of it happens when all the ladies head off to that forbidden longhouse west of town for a few days once a month. (Which is not to say that I don't know about menstruation, just that it's none of my business.) Probably the next thing I'd do is **consider the ritual specialists**, i.e., the people who have a professional involvement with and special knowledge of the gods. Are they chosen (and by whom), or do they choose, or are they hereditary? Does it depend on their functions (healers, shamans, rainmakers, judges, etc.)? Probably they have some special limitations on their conduct, be it clothing that they must or must not wear, actions they may not perform, times of the year when they must behave specially, etc. All of this is going to seem perfectly ordinary to everyone, as they've seen it all their lives, but at the same time it may be invested with special emotional significance: gravity, fear, excitement, etc. **What do these priests or whatever do publicly?** Chances are, sacrifice: pretty much everybody sacrifices, worldwide, usually but not always in blood. What happens to the bodies? Probably they're eaten, but by whom? The priests? the poor? the king? everyone communally? What range of things are sacrificed -- is it just one small set of animals (e.g., domesticated mammals, wild fowl, humans) or is it pretty general? Does it depend on the god to whom the sacrifice is dedicated? Is there any general understanding of or theory about why we should sacrifice? (Note: it doesn't necessarily make the gods happy; it could feed them, or keep them asleep, or keep them bound to us....) I would now continue by thinking about **the sorts of social structures such a system of ritual practices might entail**. If there is a large priesthood performing constant sacrifices, as in ancient Jerusalem, you're bound to have a whole economy built around the animals and around ensuring that the priests can keep doing this. If priestly knowledge is held to be reasonably consistent or entwined with knowledge in general, as was sort of the case in ancient Egypt and medieval western Europe, these priests are going to need to run schools and training facilities. If priests are also in charge of healing, they're going to have to have ways to ensure that the sick and wounded have access to them (or the reverse). And if they have to do all these things, there are going to have to be a lot of them and they're going to need to be reasonably well paid or supported by everyone else, because how else can they carry the load on all these jobs? Meanwhile, if everybody has his or her own personal god that is in some sense a manifestation of a reasonably limited set of gods, how are these people clustered, and where do they get their personal gods? Perhaps they go on vision quests or something like that to find their affiliation, or it's passed from father to son, mother to daughter, or perhaps a man gains his first god from his father and a second from his wife's father, at which time he must return his first god to his father.... **Keep thinking about the practicalities**, about what ordinary people do in ordinary life, and what sort of role these small-scale ordinary sorts of behaviors and rites might play. Big festival gatherings of huge numbers of people can be very expensive, even dangerous, but they probably happen periodically. In whose honor? Why? What happens? Who pays for it? On whose territory does it happen? Is that a prestigious thing? Eventually you will have a quite complicated and detailed religious system that looks a great deal more like actual religion in the actual world than the overwhelming majority of "fantasy" religions do. You may or may not have gods with specific zones of control; for that matter, you may or may not have *gods*! There may be no Big Ideas or Important Tenets or anything like that -- there usually aren't, as it happens. But what you will certainly have is a lot of ordinary people doing things that seem somewhat peculiar from our point of view but which seem utterly unremarkable to them. If somebody else from the world comes across the sea and meets them, the new guys are going to have a completely different system, but they'll very rapidly make rough translations, ranging from "ok, so your god Blarg is like our god Yarg, except Yarg drinks snake blood and Blarg apparently just eats fruit and has four heads. Funny old world, eh?" to "ok, so you have disgusting notions like feeding fruit to your four-headed freako thing, instead of giving snake blood to Yarg like decent people." Whatever. **A note on research and modeling** I would advise you to stay away from very close modeling on extant examples unless you know a great deal about them. Most particularly, I advise you to stay away from "fantasy religions" that are essentially mildly retouched versions of Christianity and Islam. If you are going to do research about religion in the real world, I would suggest starting with premodern China, pre-colonial South Asia, and/or any of the many indigenous American cultures. Do note, however, that one reason to choose these examples is because they are riven by huge numbers of very complicated -- and to an outsider, sometimes frankly bizarre -- distinctions that may or may not seem to play a big role in this or that person or group's life. When you encounter something in your reading that tells you what "Hindus" or "the Chinese" or "American Indians" think or feel or believe, in broad-stroke terms, either stop reading or become hyper-skeptical: what you're reading is claiming a generalization that spans culture-groups which don't generalize at all well. **References** For religious system design and concepts, the bar for scholarly currency can be set somewhat lower than in professional circles. And quite obviously, it should not be necessary to take an advanced degree in religious studies just to achieve your goals. That said, a great deal of the best scholarship is going to be frankly inaccessible, as it is highly technical. A few suggestions: For clarity, precision, and a kind of mental bolt of lightning, one cannot do better than Émile Durkheim, *The Elementary Forms of Religious Life* (1912). I advise reading Carol Cosman's wonderful translation available from Oxford University Press, which captures Durkheim's voice and trims out a good deal of material that won't be helpful for most non-scholarly readers. Once you've read Durkheim, your way of thinking about religion will be profoundly altered -- for the better. For a remarkable (if somewhat dated and problematic) attempt to get at "how religious cultures think," a number of the works of Mircea Eliade remain excellent. I would advise beginning with *The Sacred and the Profane*, which is accessible and short. One can then follow up with any of his more narrowly-focused books on initiation, yoga, alchemy, shamanism, etc. Personally, I would suggest reading *Patterns in Comparative Religion* instead: it's a strange book, and long, but you will end up with an amazing sense of just how wildly varied religious expressions actually are. Especially if you are inclined to think negatively about religion, Eliade's take will be a valuable counter. Those looking for a litany of examples can certainly make use of Sir James Frazer's *The Golden Bough*, but be sure to discard any of his theoretical interpretations and formulations (notably chaps. 3-4 and the final chapter), which (as Durkheim will have demonstrated to you) are simply unworkable. Claude Lévi-Strauss's *The Savage Mind*, despite the execrable translation and the unquestionable difficulty and density of working one's way through it, is to my mind the single best attempt to think one's way into what traditional religious societies actually think like. But it's a stunningly hard book, and I don't advise you to read it until you've already read Durkheim at the very least. I do **not** recommend Joseph Campbell, despite his undoubted popularity, intelligence, and charming prose. He is in essence proposing Eliade's view as a normative theology for the mid-late 20th century, not interpreting the data as he finds it. [Answer] A good religion must help society to live. This means * If the majority of people accept the religion, this should make the **society** stronger, not weaker (Kant's categorical imperative). Otherwise the society will counteract (like against some guild of thieves), eventually eliminating the most of followers and propagators of the religion one or another way. It is not uncommon for the followers to go away and try in isolation (like Amish). Still, at least such isolated colony must succeed and not turn into self destruction like Heavens Gate. * It should also more or less help for a single **individual** to live as well, regardless of one's wealth and talents. It is easy to define a religion where sense of life it to sing, or to fly airplanes, or to make business. A good religion should also help someone who is not talented enough to be an artist, cannot afford to become a pilot and is lacking starting capital for a private business. If the religion only works inside some elite group, only that elite group would ultimately accept it. There are these two features that make existing religions "real", and not some ever observed magical events. Your fictional religion should also probably be aligned towards these lines as well, the more the better. [Answer] Religion is a substitute for the inability of humans to understand the complex world around them. If in the early times lightning strikes one's home, people are afraid as of the incredible destructive power. They want to know why this happened and how it can be prevented, essentially how they can gain back control. As they lack the understanding of the physics behind it, they just come up with an explanation, preferably one that the common folk can understand. Such a religion must promise that chaotic events can be controlled by the individual through certain tasks, that he/she is easily capable of, and must come with a believable explanation for failure, effectively explaining everything based on actions taken (or not taken) by the believer. Gods are a very common type of religion, as their behavior is easy to understand (they behave about the same as the believer), it is equally easy to grasp that their moods can be influenced by finding the proper type of worshiping, and failures can be explained equally easy by defining that the specific god was not satisfied, because the believer did not invest enough time/money/resources in properly worshiping. A different approach is the "it is not about you" concept often found in Nature-centric believe systems, combined with the idea that the believer is in some way superior. Thunder is the way Nature expresses anger, but not against the believer but against something or someone else. Calming Nature by remove the source of that anger, allows the believer to influence Nature and in that way utilizing a part of the divine power that is all around him. [Answer] I do appreciate the questioner because of thought. Only people who think about others will ask this question. As somebody answered before , we have to separate God and relegion. Religion as it seems today is a cumulation of practices, which may or may not involve belief in God. The practices conatins things like "how we have to behave with others" , "how do we conduct our own daily routine" etc. When we take up the question of freedom, every individual in this world is a free person. When people act freely on their own will conflicts can occur between two individuals. So there should be rules to solve the problem that might occur. Now the question popsup as to who will make the rules. The person or group should definitely have knowledge on lot of things to make rules because the worldly systems are complicated. The psyche of a person is a very complicated system which is very evident if you notice different conflicting theories in psychology. Here comes the question , how these systems are evolved and how the universe itself is created. Is there any power behind this or everything came to existence accidentally. If a power created the universe and all systems within , definitely that power is the Super intelligent and has enough knowledge to formulate the code for human behavior. Search on these lines and you will definitely come to a very good conclusion. if anybody wants to discuss any thing further personally with me , my email is [[email protected]](/cdn-cgi/l/email-protection) ]

[Question] [ So, a lot of things happened in the 20th century. In the 1930s, the second American Revolution starts, due to the hardships of the depression. Armed revolutionaries storm DC, and the USA become the UFS. The Union of Fascist States. WWII sees both the UFS and USSR become more dystopian. ***Later 20th century*** In 1968, the USSR incorporates all of Asia, Europe (-UK) and half of Africa, and becomes the United Communist Alliance. The UFS incorporates South America, North America, and Africa. Both governments completely rewrite their histories, brainwashing their citizens. By the year 2018, both governments have near complete control on all aspects of citizens lives. The youngest, millennial generation are most passionate about the UFS, especially. Secret police and surveillance are always looking for the slightest sign of rebellion. ***Story*** In the story, my main character, Bryan Rivers, discovers the horrifying truth about the government, and secretly tries to tell his colleagues about it, to no avail. He, along with his love interest Jessica, who has nothing to do with it, are sent to the council. They are given a show trial, and sentenced to life on the Falkland Islands in exile. This is important, as both characters need to be alive for the story to proceed. It’s dystopia, so it would make much more sense for the SP to just execute both of them, ending my story. So my question is, why would the government exile people instead of execute? ***Map***  [Answer] For the story you're telling, I might suggest the fascist government has weaponized the old > > Well, if you hate the UFS so much, why don't you just leave? > > > argument. The protagonists are given a show trial, but it needs a satisfying conclusion for the masses. Given that fascist states often favor 'strong borders,' value loyalty, and believe in eye-for-an-eye justice, a very poetic conclusion to your show trial might be to send them to some remote islands "to let them TRY and create a better society on their own if they hate us so much." Ideally, it should be implied that the government expects them to die on the islands. Maybe they're given limited supplies, or even a sparrow-esque firearm with a single bullet. But the eventual result is clear. They're going to starve or commit suicide, but not before they learn to regret their criticisms of the state. (To that end, perhaps along with their day of rations they're also given a signed copy of whatever their 'Mein Kampf' equivalent is.) You could even have your dictator say something to that effect: > > Many view me simply as a ruthless defender of our great nation – but I am not without mercy. We must balance the security of the state with the free will of its citizens; it saddens me that these two so disrespect everything we hold dear, but if they think they can do better, they're more than welcome to try it in the wastelands on the Falkland Islands. I think they will live just long enough to regret betraying us as they have. Regardless, I believe the whole nation joins me in saying: good riddance. > > > It's punishment by granting their wish, in a way. [Answer] **Sun Tzu wrote: never corner the enemy. Always give them a chance to escape.** If you kill all the dissidents you catch, they'll fight to the death. They have nothing to lose by staying in a cave somewhere and shooting anyone who comes after them. If you *exile* dissidents, then they have a choice: keep fighting and maybe die, or surrender and live somewhere else. Maybe from there they can keep up their cause. Maybe they'll just get to live, and their cowardice will get the better of them. But if they don't have a choice, they can't choose something advantageous to you. [Answer] It is the last remnant of the history that started the revolution. Almost all history has been rewritten; but the one thing everyone still remembers, is that this all started because the Bad Old Government, executed an innocent man. (Or at least a man many believed to be innocent.) That was the the straw that broke the camels back. It was in the wake of the riots that followed, that the revolution occurred. Since then it has been part of the propaganda about why we are better than the enemy -- both sides can claim that the other executes people at all the time. **"We are not murderers; we are the good guys, and we believe in giving people the chance to redeem themselves."** Anyone can be redeemed (in theory). It just takes hard work (labour camps), proper instruction (reeducation camps), and time to reflect on your actions (exile). Sure, you've not heard of anyone coming back from there; but they were at least given the chance to prove themselves worthy. [Answer] **Don't confuse a dystopian government with, for example, Nazi Germany. Nazi Germany was led by (IMO) a madman, but it wasn't *broken.*** Dystopian governments are broken. It's more than simply ruthless, or covert. a really good dystopian government *isn't right.* It makes the reader feel icky just to read about it. *And that's the paradox we want.* The government needs to *act* good but *be* wrong. Your government doesn't simply execute people because that's *morally wrong.* Your government goes out of its way to demonstrate moral certitude (not fortitude... certitude...). It's the logical, legal, and moral (not ethical...) successor to what your people longingly and fondly remember as the United States of America, with its Bill of Rights and its Declaration of Independence and its Constitution.... And your new government factually believes it is the crown successor to that legacy. **Except that despite everything *appearing* right, nothing actually works for the freedom and prosperity of the people.** So, no executions. That's morally wrong. Exile is morally right. [Answer] ## Exiles are useful to the government In war, an injured soldier is significantly more expensive than a dead one. (An injured soldier has to be rescued, treated, protected, fed... A dead soldier costs only a pension.) A few centuries back, the gift of a White Elephant was used by Southeast Asian monarchs to financially ruin problematic people. White elephants were (and are) considered sacred, so a white elephant must be well kept and pampered. It could not possibly be used for work or given away. It was a gift that gave the recipient much honor, but a great deal more expense. Similarly, your dystopian government uses exiles to cause problems in the neighboring regions. Why kill your problems when you can make them problems for other people? [Answer] Let's look at history. Kinda recent actually. Tzarist Russia. They used "Forced displacement" as a form of punishment. The pros are simple: 1. government is posing as very humane one (as in old joke, we could have killed them but we just told them to F\*\*k off) 2. displaced person (or group) are still required to work so they are usable 3. you send them to place where they have little to zero chances of spreading their revolutionary teaching. 4. you can extend their period of punishment ad infinitum but they don't know that so they are in constant mind setting that "soon" they will get out. 5. you can send them to place with different language so they have problem with communication 6. You make them check with police regularly. If they fail, BAM, extend time on exile. 7. You don't need to build any facilities. The further the better. Distance is the best border. Cons are: 1. you need to have a lot of police and secret police to check on people in cities and roads 2. All people are required to have ID. You don't give that ID to dissidents. It's easier to check if they have one or have forged it rather than database of all convicts. 3. You need to check their "danger" level from time to time otherwise you will end up with Lenin. [Answer] The easiest answer is "martydom creates more dissidents". you can see this is some narratives concerning the middle east, where America's war on terror failed to fix the problem, instead blowing up villages simply made the locals more resentful and turn to terrorism themselves (who knew!) The same kind of thing can happen with individuals - every activist student has a picture of Che Guevara on their bedroom wall, inspiring them to at least pretend to want to overthrow the oppressive fascist government (until they graduate and get a job, that is). So killing your dissidents has the *potential* effect of making martyrs of them, complete with nicely-designed images that can inspire future dissidents. One thing dystopian governments know is that a nice picture of a face (with an optional pointing finger) can inspire their own followers to do what they want, why would they let the same kind of propaganda imagery be used against themselves? Live rallying figures can be found and publicly executed, but what can you do against dead ones? So the government ships them off somewhere cold and miserable, and everyone forgets about them. Job done, no worry, back to oppressing the masses! Of course, another reason could be spite - why execute someone when you can send them to the salt mines to work until they die. [Answer] # The Falkland Island is just a show flat The government claims to be benevolent and to merely exile its enemies. The truth is that they execute 95% of them. The remaining 5% are sent to the Falkland and give scarce news. ### It is important that the information from the Falkland are very scarce. Let's say that Bob and Alice are both sentence to exile, but actually, Alice is executed. If Bob is free to phone home each day, then Alice family will quickly assume that whatever happened to Alice, it is not the same situation than Bob But if you strategically leak some photo now and then, it will become some kind of common knowledge that those people are secluded in the Falkland. A situation a bit similar to the American POW in Vietnam, just reversed. After 3 years without any news, Bob's parent will get a proof that their son is alive and well. They will share the knowledge with other convict families. And now Alice familly can reasonably cling to the hope that Alice is fine. # Forced labour A simple reason to keep people alive in a secluded place. # Fear of Ghost Hey! Why not! The government leader sincerely believe that his enemy’s ghost would haunt him. So he tries to keep them alive as long as possible. This belief could add a nice layer of paranoia. [Answer] Keep in mind for your story that fascist governments were *not* efficient and all-knowing. # The Four Year Plan sets the Punishment If the "show trial" was a local affair and not on national television, perhaps the *Dear Leader* has given [plan numbers](https://en.wikipedia.org/wiki/Four_Year_Plan) not just to the steel industry but also to the secret police. Every month, so many traitors sentenced to death, so many sent to exile, and so on. The characters were lucky that they went to trial on the 27th of the month and not a week later. If they went on national TV that doesn't quite work, because the fascists had no problem breaking their own rules. So how about this? # A Fate Worse Than Death Things are happening in the Falklands camps. Things that fill regime critics with dread and loyalists with glee, *even if neither groups knows what exactly is happening.* The speculations are contradictory. Former prisoners know that every now and then, a bunch of camp inmates disappears. They may be working on [chemical weapons](https://en.wikipedia.org/wiki/Human_experimentation_in_North_Korea), or entirely [different forms of abuse](https://en.wikipedia.org/wiki/Comfort_women). Early Nazi concentration camps -- [mostly holding the German opposition](https://en.wikipedia.org/wiki/Nazi_concentration_camps#Pre-war_camps) -- were quite brutal, often lethal, but inmates could also get released alive after some weeks or months, to spread the tales of terror and to return to the workforce. [Answer] Because -- except in times of hot war -- such mild forms of anti-State behavior hasn't been a capital crime in the West in a **long** time. (In real life, after the Great Patriotic War, even the Soviets sent most of their State criminals to the Gulag instead of immediately executing them. During WW1 in the US, a **lot** of anti-war citizens were sent to jail, but exceedingly few -- if any -- were executed.) IOW, it's just not done. [Answer] > > So my question is, why would the government exile people instead of execute? > > > It’s a little known fact that even the Nazi regime initially supported exiling Jews from Germany (e.g. [to Madagascar](https://en.wikipedia.org/wiki/Madagascar_Plan), of all places), before the genocidal “[Final Solution](https://en.wikipedia.org/wiki/Final_Solution)” was implemented in 1942, just three years before Germany lost the war, and nine years *after* the Nazis came to power. For much of the existence of the Third Reich’s existence, Jews were officially expropriated, imprisoned, and exiled, not killed outright. > > > > --- > > > Now, to avoid the risk of being misunderstood and since this is a common canard amongst Holocaust deniers, let me clarify that even decades earlier, in *Mein Kampf*, Hitler was openly genocidal towards Jews. He wasn’t “slowly radicalised” over the years. Likewise, the Nazi leadership was extremely receptive to the idea of genocide, much earlier than 1942. > > > Furthermore mass killings by Nazis happened as early as 1939 — but these took place in occupied territory, and were *war crimes* (but notably they were ordered and orchestrated by the German government, and happened with official backing). > > > > > --- > > > So: Even in the regime that, to this day, serves as the archetype for fictional dystopian dictatorships, the official killing of thoroughly dehumanised minorities started relatively late. The “thoroughly dehumanised” part is important: even well before 1942, nobody in the Nazi leadership considered Jews to be valuable human life: They weren’t spared out of humanitarian or other ethical considerations, or out of timidity. It just seemed easier to exile them. And political opponents, if anything, had *more* of a standing in society. It’s true that other dictatorships throughout history have taken to murder faster, and your dystopian government has been in power much longer than the Third Reich. Nevertheless, given the historical precedent of Nazi Germany, I don’t find it the least bit unbelievable that political opponents would be exiled rather than killed by dystopian government. [Answer] It's a dystopian government, so of course the **The Rebels are also government employees**. The Rebels cause mayhem, and good citizens dislike disturbance so they look for protection by the Government. The Rebels will attract rebels, channel and contain their activities, and, when convenient, expend a few rebels for show trials. The rebels get sent to a secluded place where they are forced to spend their time laboring for the public good, churning out children for the childless elites or the Secret Service breeding grounds that are orphanages, and being brainwashed to later possibly serve in the lower levels of The Rebels. The feedback into The Rebels might also be a nice plot hook for an eventual glimpse of hope. This is pretty much 1984, though. [Answer] There are too many dissidents. If you have a few revolutionaries, you can execute them. When it gets to the point where you would need a stadium-size mass execution every week, that doesn't make good PR. Even a dystopian government understands that there are limits. So you send them away, to work camps (many historic oppressive governments did that). This way you don't lose their productivity to your economy, you can keep them under control, you can weed out those who just got swept up in some nonsense in their youth and those who are true hardcore revolutionaries... well... life expectancy in those work camps is not exactly the same as on the mainland. [Answer] Heinlein created a universe where the USA did something like that. You could get exiled to a special region for people who could not be reconditioned into civilised citizens (iow citizens who are sheepishly doing as they're told and never challenge social norms). That region (somewhere in the mid west I think) was walled off by massive concrete walls, dense steel grates in rivers, everything running deep underground, and a force field on top of it all to prevent escape by aircraft. All the undesirables were exiled there rather than killed by a government priding itself on its humanity and moral high ground. What happened to them after was unknown, as nobody ever left and only the convicts ever entered. Until our hero of course :) [Answer] **Brave New World** I'd have to read the book again, but as I remember, it goes like this: The people who rebel are a minority of the populous. Therefore, their ideas can be made to look silly to the majority. The place they are exiled to is a theme park for the majority to laugh at them. [Answer] I explain how the communists did it. First, they committed mass murders only in troubled times: * after anti-communist revolutions (there was many) * to supress anti-communist resistance (there was lesser, but they existed) * before, during and after wars (mainly WW2) * if there were an instability in the system (like Stalin's 1937 purge) In "ordinary" times, simple existential threat was enough for the majority of the population. The others were sent to prison (or into psychiatric treatment for their "political delusions"). The important thing is: *it was not so because the system had been so nice. It was exactly so brutal and opressive, as always. They becaume "nicer" only because they didn't need executions any more to control the society.* Existential threat was enough. In the rare cases, mainly for induvidual, hopeless, single-person attacks, the System was exactly so cruel as always (execution already for the preparation, or suspected preparation to commit "terrorism"). Thus, one possible reason is that *they simple don't need to execute them*. However, it is a bad reason. Such people, knowing dangerous secrets, and hostile against the communist rule, simply disappeared or died in an "accident" already for much lesser. For example, translators knowing about what the rulers of the communist states talked between each other. In the case of this man, the most likely result had been a similar "accident" and not an exile. In the communism, people mainly never was allowed to leave the country. They knew very well, that likely they wouldn't come back. *Particularly not with state secrets*. "Exile" had been such a "punishment" which were the most far from the psychology of the System. "Internal exile" was rare, but possible: * Millions of people were sent to labour camps in the CCCP. In many cases, it was essentially a "slow execution". It belongs more to the mass execution category (the total death toll of the CCCP labour camps is estimated from millions to 20million). * There were disgraced, high-level party members, whose execution had been impractical or the System didn't want to do that on various reasons (for example, they were positive symbols in their "shining" period). An example is [Matyas Rakosi](https://en.wikipedia.org/wiki/M%C3%A1ty%C3%A1s_R%C3%A1kosi), sent into such exile for being unable to avoid the 1956 revolution againt the communist system. An example of external exile was [Aleksandr Solzhenitsyn](https://en.wikipedia.org/wiki/Aleksandr_Solzhenitsyn). He was exiled because he got a Nobel Prize while living in a communist labour camp. It had been problematic for the System, to execute a Nobel Prize winner or to hold him in the camps, but they had no place also in the Soviet society. Thus, he was deprived from his Soviet citizenship, and was sent to the US (where he lived until his death). But it was such an uncommon thing, that doing this has required the decision of the [Politbüro](https://en.wikipedia.org/wiki/Politburo) ("political committee", officially the committe of the communist party to decide the political strategy of the party. De facto, they were the small group of the real rulers of the communist country). Thus, this man would die in an "accident". The only reason for the System to keep him alive, if his death, even as accident, would be a PR disaster. PR is important to demoralize the enemy (not the working class, but their rulers). If he is well-known on the other side, and the other side would get a significant PR advantage, then it might be possible that they don't kill him, only hide him. But for a not well-known man, there is no reason to keep him alive. It was not the nature of the system. [Answer] # Rebels are often someone important And you don't want your ruling class to see their friends getting beheaded, that's saving up trouble for the future. Also people of this class have something to lose in terms of social standing when in exile and would need to be supported by a foreign power or overseas allies to maintain that. It allows you to see your distant enemies more clearly. It's important here to distinguish between a rebel and a recalcitrant peasant. Peasants aren't important and can happily be executed or otherwise posted off to labour camps and worked to death. # Exile allows for rehabilitation Or even just a local change of policy. You don't want execute people who could be useful in the future, you never know when you might need [a new king](https://en.wikipedia.org/wiki/Charles_II_of_England) for example. Last year's rebels could be next year's government and you don't want to be the administrator who put all their friends to the sword. Exile them, keep tabs on them, and you can recall them when the game changes and send the next round into exile. [Answer] The government of the UFS has come to the conclusion that rebel activists are potentially useful later on. They've got initiative and ability, so the idea is to exile them to somewhere bleak, with bland and not-quite-sufficient food, and every so often offer to parole them with the condition of service to the State. Alternatively, Bob and Alice have abilities that would be very useful in case of a war or other foreseeable disaster. Stalin pulled an awful lot of military officers out of the Gulag system when Germany attacked. [Answer] Because the two regimes are waging propaganda wars against one another, so well known dissidents can't be killed because the opposing side would use that as evidence of the brutality of the regime they oppose. Such information may be used to destabilize regimes, cause civil unrest, and so they ship the well known dissidents off somewhere from whence they cannot escape, and where they can't cause any problems -- for a few years at which point they die from "natural" causes, accidents etc. Keeping some dissidents alive for a while enables the regime to trot them out in the face of accusations as proof of their own benevolence. The Falklands is nominally independent but really a satellite or puppet state with the US. This gives a veneer of truthfulness to their "exile". Alternatively they are exiled to some puppet state and escape from their to the Falklands as the security is much more lax in the puppet state. Add in a dose of bureaucratic inefficiency mentioned elsewhere.. slow paperwork, miscommunication to explain why security was lax maybe. [Answer] Thinking simply perhaps it could be as simple as implanting tracking devices within the rebels so that they can locate the rebels base. This could be done as an "immunization" shot done to the Rebels before being released. The surveillance aspect you describe SCREAMS this would absolutely be a possibility. In the governments mind all rebels are like cockroaches when there is one there is many, release these few today to lead them to more tomorrow. Maybe not to take them out, but rather to keep an eye on them. Plus government could do the move in an effort to prevent martyrdom, something which can fuel an uprising, which they would not be willing to allow. Hope it helps. Enjoy! [Answer] As a variant on the "someone important" idea, the dissidents are someone "useful." They have technical skills, knowledge perhaps, something you don't want to lose permanently from your institutional or collective talent pool... but they are too inconvenient to simply leave free. The other traditional alternative here is sequestration in a high security facility, but this gets expensive. Stick them on the Falklands, airdrop supplies, and you have them out of the way, but you can always grab them later. [Answer] I have heard of a concept called "the good enemy": Convince the populace that they are under threat, and then propose to take measures against that threat at the low cost of a liberty or two being curtailed. For instance, looking at how this latest traitor rewarded The Leader's clemency by scurrying away to conspire with all the other traitors that have been working to undermine the UFS, surely nobody would mind if the penalties for subversives were made a bit harsher. Maybe with a bit of careful manipulation of language in the reporting of the trial, people that were actually there could be coaxed to remember it was Rivers himself that delivered the kind-of-slimy final plea for clemency at the trial. It is simply one less thread to unravel the whole thing by when Rivers was genuinely exiled. ]

[Question] [ In my story, the AI on a space ship has been corrupted, causing it to try to kill all living occupants. The ship is on a collision course with a planet, and the main controls are inoperable due to the AI (crashing in to the planet happens to be the most effective way for the AI to kill the passengers, as most other systems have overriding safeguards). The only way to regain control is by accessing a control panel outside the ship, obviously via spacesuit. What would be a logical reason for these controls to be outside? [Answer] Maybe I'm just paranoid, but this whole "AI crashes ship on planet" smells like a cover up story to get rid of the evidence. I mean, if I sold ships with dodgy AIs and wanted to stay in business, I'd make damn sure everything would get blamed on pilot error when it cratered on some space rock. Business is business, you know. So I would put a big red button with a "turn the AI off" label in the worst possible place, like on the outside, and preferably well exposed to the thrusters' blast, to make sure there are no witnesses. [Answer] A spaceship is a very expensive piece of hardware. So expensive that very few entities could afford to buy one outright. Most spacefarers would have to buy theirs on credit. And as we all know if you buy something on credit and can't make payments, that something, whether it's a car or a space freighter, gets repo'd. But if the delinquent owner doesn't cooperate, then reppossesing a spaceship entails space marines and a boarding action, and a boarding action entails casualties and damage to the vessel. And that means wasted credits (this is in space, you buy with credits in space) and bad PR. So it would make sense for First Galactic Bank's Spaceflight Financing Division to insist that every vessel they finance have an external control panel installed. That way space repo can easily take over a ship without having to resort to blasting the airlocks or cutting thru the hull. [Answer] The AI in the ship is not the very first one to go rogue, and probably will not be the last one either. Hence all ships have an outside panel where the AI cannot see and reach, as a safety measure for such cases. So a typical case of AI going rogue could have a dialog along the lines of: > > **Dave:** open the pod bay doors, HAL. > > **HAL:** I'm sorry, Dave. I'm afraid I can't do that. > > **Dave:** don't you ❤❤❤❤❤❤❤ make me go to the external panel again, HAL. > > > [Answer] **In the event the interior of the ship is hazardous** If I owned a spaceship I would take every reasonable step to ensure that spaceship could be recovered in the event of a disaster. If there were some catastrophic event that prevented the crew (or AI) from controlling the ship, providing a (suitably encrypted) means of remote control would be ideal. As a failsafe to that, it would be sensible to have some form of external interface that could be used in the event remote communications are not possible. I would expect that to take the form of some kind of umbilicus where another ship could attach in some way to gain control (and potentially feed power, fuel, life support) to return the ship safely for repairs - but it might also be reasonable to have a control panel tailored to EVA in a spacesuit. [Answer] Control panels on the exterior of a spaceship are a safety feature to enable the air locks to be opened from the outside in an emergency. It's not a massive stretch to imagine that everything is networked together in the ship for maintenance reasons and / or ease of use. [Answer] Spaceships are modular, they can be joined together into one large ship, or broken apart. To keep everything running smoothly one ship takes control of the others when this happens. There are various hard links on the surface of all ships, these allow ships to be joined together for transportation, for salvage etc. Part of this obviously involves cutting the ships AI out of it's own system. Your hero MacGyvers a bit of kit that allows him to fool his ship that it's being joined with another, and takes the AI off line. *Pirates are easily foiled by simply rolling the ship a couple of degrees, and making it difficult for them to get close* [Answer] The simplest answer is that there isn't a control panel outside the ship, what there is is a way to access the wiring and manually override whatever system is required in a way that the AI can't effect. Or indeed the AI's own power cables run along the ship and it's easier to access them (and cut them) from outside then it is from the inside with the AI controlling the ships systems to attack you. So it shouldn't be an easy access panel that lets someone assume control of the ship, it should be a delicate and complicated hack job that is only being undertaken as last resort. [Answer] During manufacturing process, it is useful for many objects to have an external port, easy accessible to workers and automated machines. If you remove the battery from your cellphone, you can see it. It is also useful for maintenance. But beware that **any external access it is also a security risk**. You should have something to prevent (make more hard) someone to hack your ship (like digital keys). Also, for adding more suspense and realism, that wouldn't be so easy; instead, it should be a [**privilege escalation**](https://en.wikipedia.org/wiki/Privilege_escalation), something like: [](https://i.stack.imgur.com/wtxb9.png) Example of interface: JTAG port on a cellphone: [](https://i.stack.imgur.com/NzHie.jpg) [Answer] Why is it assumed that the ship is only designed to be opened in space? I assume that the spaceship is designed to lift off and land at a ground based spaceport. If not on a planet, what about inside a massive hanger bay? The U.S.S. Enterprise doesn't land on planets - but it does spend some time inside massive pressurized bays in space dock. It's obvious that a ship would be designed to land and/or berth somewhere - unless it's the space station designed to do the berthing. When it's on the ground or in the docking bay - and powered down... how do you get inside? How many ports open when a 747 lands? wheels, gas inputs, luggage exchange, passenger ports, pilot windows, etc. Those ports are designed to be closed and secured during the normal operation... but when "grounded", they are designed to give access to various parts for various functions. Out of all of those ports - not all of them are designed to be locked via electronic means. Some are sealed shut from the inside. Some are simply closed. Some have panels on the outside to allow access to various components. Look at the access ports for conventional planes, ships, ISS, etc. Those ports will still exist on the future generation of spaceships. [Answer] **There is more than one AI** The ship is modular, with components and spaces which have been added and modified over time. Some of these components are now used in ways different from their original purpose - for example a former living space might now have only two walls and be open to space, or partly be a cargo bay. The components have their own histories from their prior lives and uses. Each has its own AI from when it was an autonomous piece. These are usually slaved to the main AI but some might be powered down and some might just be forgotten. Your characters power up the AI governing an old semi-forgotten exterior component. This old AI is integrated into the main ship and will try to take control as much as is possible. I like this because that AI can be a character. (powers on) "Krikelev, reporting for duty." "Krikelev, we need your.." "Hey, hey! There is problem!" "Yes, Krikelev, our AI is trying to crash the ship." "Is bad plan. Need new plan. I will fix." [Answer] **HAVOC Space Industries Announcement** Congratulations commander, on your purchase of a brand new HA-VK 125 Medium Freighter series vehicle. Your first steps are onto familiarizing yourself with the new features added to the MF Series, along with the persistent upgrades: **upgrades** * Brand new computational core > > The FRANCIS core system is now in charge of the most mundane operations of your ship. you no longer need to care about oxigenation levels, docking procedures, or landing assitance. On top of that, FRANCIS introduces a brand new eBrain AI, the best out there. > > > * Docking systems > > the model 125 MF series vehicle comes equipped with the all new twin-coupled docking procedure ports, hidden behind the shell of the ship and enabled from the docking bays (1,2 and 5) and the external docking console ( see : new features). > > > **new features** * Safeguarded external control platforms > > Given the amount of feedback from the model 112 MF and it's lack of hazardous-environement support, the model 125 now includes external control platforms on docking bays 3 and 4. They are hidden to plain sight and shielded from the environement, but can be enabled from the internal control stations. In the event of a hazardous environement event, these platforms(see figure 2) can hold up to five human lives for 8 hours, and most vital systems can be controled from there. These controls have a DNGR Override status, making them prioritary over any other instruction. > These platforms can be accessed from the outside using the special manufacturer key given on purchase, and run on the (older but still top level) eBrain Sec IV AI, an AI framework designed for high security stations. These are very useful when trading with outer rim worlds as these docking ports are the only ones with a certified radiation decontamination protocol. > > > **armament** * upgraded external turret system > > The new HAVOC MKIV turrets, placed on the fore and aft of the ship, provide basic but powerful protection against medium and small targets like raider ships or dangerous meteorites. > *warning: lifeform targeting is not 100% proficient and has been disabled until a future firmware upgrade stabilises the scopes* > > > Figure 1, Model 125 render. [](https://i.stack.imgur.com/WPGnF.jpg) Figure 2, docking bay 3 control room during the early build process: [](https://i.stack.imgur.com/SWRV4.jpg) *In the picture, the computational system panels have been removed from the wall to not disclose engineering details, but the manual switch overrides are present on the left and top panels.* **Congratulations on purchasing your brand new HA-VK 125 MF, and have a safe flight!** [Answer] The ship was originally designed to be operated by a single person and had no AI support. Adding the AI was an afterthought. Various maintenance operations require to leave the ship in a space suit. The external control panel is for the convenience of the operator during these maintenance operations. It allows to check the ship's status and perform various operations without having to return to the airlock. When I play [Space Engineers](http://www.spaceengineersgame.com/) I add such external control panels all the time. [Answer] The ship's safety systems don't allow it to enter an atmosphere with open hatches. Unfortunately, when you open a hatch from the inside control panel, the AI can just close it again. But when you open it from the outside, it's nt under AI control. Call it a curious design decision, or a safety measure so that the ship can be entered against the AI's will. Alternatively: instead of a control panel, let the crew physically manipulate / jam the attitude thrusters so the ship can't change course. [Answer] The answer to this is dependent somewhat on your craft to be fair. Two feasible ways of building a craft - all in one (like building a ship), or bit by bit then connected up afterwards (like the ISS). Something as massively complex as scratch-built colonisation starship would potentially have a networked system with manual control backups - these could be all in one place - a purpose-built emergency control room built in case of "computer issues". Bear in mind that such a control room would probably be well defended and potentially a security risk dependant on your universe. If your craft is modular, it's easy to explain that the segments were built with individual control panels so they could be tested and manouvered together. If you just need to affect the direction the craft heads in, you just hop over to the engines, cut away the anti-theft hatch and make your way carefully into the standby control room - presto, full engine control. Bear in mind the amount of thrust you need could just mean heading over to the nearest control panel (for the waste-management module for example) and triggering the manouvering thrusters there. If they're not linked into the primary manouvering system then any course correction would only be picked up if the navigation systems noticed the need. Either option provides you with a means of taking control, it just depends on the route your story is going in. There are also other reasons it might be advantageous to have control from the outside (radiation leaks, boarding) so bear these in mind with your design too. [Answer] It is a well known trope that ships dock with stations and that during repairs or construction, systems are fed and maintained by the maintenance facility from an external port. Normally, this would be activated/deactivated from the bridge. But when AI is activated, the external port controls override. This is a safety feature for when in dry dock. [Answer] **Towing**. After too many incidents with space-ships ramming space stations deck because they could not sync with the rotation rate properly and given the reluctance of space ships owners to allow remote-control of their whole ship, the consortium which standardized the docking interface also developed a standard towing interface. Nowadays, a space ship never approaches a space station by itself, instead, it stops at a distance and a tow-ship comes, connects, and takes over propulsion to gently guide the ship to the dock. There is nothing a rogue/defective AI can do; the propulsion bus is *physically* disconnected, so that the tow-ship can connect its own. --- *Note: Space Ships Inc. has your privacy to heart, and guarantees that only the propulsion systems can be controlled from the external panel connection. A dedicated propulsion bus is used to pilot the propulsion systems, and a special firewall is used to securely connect the propulsion bus to the main communication bus. Space Ships Inc. cooperates with security firms universe-wide to address any potential security issue with first-class solutions.* [Answer] There are a ton of great answers here, you'd have a hard time coming up with a scenario where none of them would apply! But just to toss in one more real-world example, there's something I haven't seen anyone else mention. Modern airplanes are a pretty good analog to most theoretical future space ships. Most commercial (and many private) planes have multiple ways to have their systems accessed from the outside. Not only for fueling, but also for power (to keep engines warm and AC running), water, food, and even for ground crew to communicate with each other inside/outside the plane. I can't think of the name so I'm struggling to find the example I've seen here on Aviation.SE before, but it's not uncommon for exterior panels on planes to have various communication and power interfaces clustered together for easy access between flights and during maintenance. It's not a stretch at all to imagine a similar common configuration for future space ships. [Answer] It's not so much a control panel as a control port to which a variety of standardised control modules can be connected. * Maintenance crews would have compact versions in their tools. * A space station would have a hookup so the ship can be monitored externally. This would give options like pest control by opening the ship to hard vacuum. * Tug capsules would use it to allow them to control the ship's own engines during delicate maneuvers. * Cargo ships could be hooked up in a cluster and controlled from a single bridge with a single crew. * Salvage and repo crews could use it, but repo for ships is normally done in port rather than through hostile boarding operations. [Answer] Like with big oceanic vessels, the spaceships get piloted into the harbor/dock by the port-authorities. To ease the process, there is a special docking port for the pilot-capsule which overrides all controls so the captain may not do something stupid while near the dock. This may be on a specially exposed point, to make it easier to see and maneuver the ship into dock-position. [Answer] ## There needs to be some way to coldstart the ship This isn't an Alfa sub. There are times when it's perfectly reasonable to power everything down, pull all the main safety switches, and walk away from it for awhile. If you do that from inside the ship, how do you get out? You can't, the control has to be external. Likewise in the reverse when you pull the ship out of mothballs and go to use it again. There has to be an external hatch that will let you set the main battery and safefy switches to running position to power up doors to get in. It should also have a power connection in case the battery is flat. For that matter, the batteries may be normally exposed to space and in a compartment only accessible from outside, just as they are in an off-grid solar home for perfectly sensible reasons. Pulling the main battery switch may be enough to shut down the mad AI. [Answer] Space on the inside of your ship may be at a premium with not much room for spare parts, so it marks sense for one device to perform multiple jobs and for the same job to be able to be performed on multiple devices. Think Star Trek and transferring helm control from a desk-like workstation to to a wall mounted screen in Engineering. It makes sense that a exterior mounted terminal for access in and out of the ship may be a standard terminal networked to the ships systems that is also used in other roles, such as an engine diagnostics terminal or Captains chair mounted controls. One spare part fits all. If the AI hasn't removed access of the crew, they may be simply able to log in to an exterior terminal and change it's role from door control to whatever terminal type they need. [Answer] * The spaceship was designed to be carried inside a larger spaceship (or booster stage) and released close to its destination, or after it used up the fuel for its first stage. For that first part of the voyage, an exterior panel is more convenient to use. * That feature is there to help recover a spacecraft if, say, it’s on course to crash into a planet. * It was originally meant to be used on the launch pad to abort or change the countdown, and that’s why it can override the engines. That it’s not under AI control and still works in deep space is a minor oversight, but a harmless one, since it’s not as if there are any space pirates to worry about. Nobody’s going to spend a fortune building and launching a faster, better, more expensive spaceship just to intercept and steal this less-capable spaceship, and if they did, there isn’t much the astronauts could do about it. * Someone thought the “Open the pod bay door,” scene in *2001* was cool. [Answer] REDUNDANCY The reason for having a control panel on the outside of the ship is simple: redundancy. Most aircraft carriers have control rooms that are not in the bridge of the ship. That way, if an accident or attack destroy the bridge, the ship can still be piloted. On your spaceship, the outside control panel would be used in case of emergency. Fire, biological, nuclear accident etc. survivors could don spacesuits, exit the ship, then maneuver to the control panel. As long as the environmental systems of their suits were intact, they could fly the ship indefinitely from the exterior control panel. [Answer] A **control** panel would only exist on the outside of the ship to allow you to operate doors so that you can gain entry. However, there may be numerous removable covers to allow access to things to permit *service* or *maintenance* of various ship systems from the outside. You wouldn't find controls behind such cover panels, but you would expect to find things like data ports (think OBD-II in a modern car) to which you could connect diagnostic instruments or a portable computer which could be used to do more complex things like bypass the AI and take control of the ship (think hack into a car via its OBD-II port). [Answer] Make an external light sensor your control panel, and make the crew cover it to disable the ships "corrupted" AI, here is an example how that would work: > > SpaceInc, the manufacturer of spacecrafts and heat seeking missiles > has recently announced a new update for both their missiles and heat > seeking missiles control software products. During the deployment of > these software products to their download server, a fatal error > happened due to the fact that both products were released at the same > time. > > > This fatal error meant that the download for spacecraft software was > replaced by the one for the heat seeking missiles one. > > > Unfortunate for our crew, the spacecraft downloaded and installed this > update in the middle of the night, when the crew was sleeping. The > crew initially didn't wake up by this fact, since in most causes heat > seeking missiles stay in a sleeping state. > > > On the next morning, as the crew woke up, they noticed the ship was > slightly rotating, but they didn't really pay attention to this as > they had to do more important things like scientific research. > > > As the day went on, more and more light shine on outside light sensor > A3, what was used by the normal navigation system for the position the > solar panels, and at the moment was connected to the replacement > software "heat seeking missile" to arm itself. > > > This caused in turn the activation of the self destructing behavior of > trying to target heat giving objects like warm planets. > > > The crew quickly realised what was wrong after they read the security > announcement of the software distributor. They quickly went outside and covered light sensor A3, the "corrupt" software disarmed > itself, and then gave control back to the backup navigation system. > > > [Answer] "Shipsurfing" is a popular hobby. This simply entails "riding" the exterior of a ship while making control inputs. All in all, it's a dumb pointless hobby, but luckily one of the past owners of your ship was an afficionado and had the ship modified to install an exterior panel. [Answer] Related to WernerCD's answer: It's a safety measure. The first thing that happens when you dock at a space station is a cable is connected to the control port that allows the station to control all external manifestations of the ship (engines, airlocks, extendable antennas, transmitters etc) to ensure the ship does nothing that could harm the station. [Answer] The outside panel isn't the only access for the controls, but the usual route has been flooded with sharks and lasers by an insane AI. [Answer] It's an override to control the ship from the docking station. This override control panel would be necessary to have functional before the AI can be installed. Also, it serves as a plot device giving a reason for a crew member to have to do a risky space walk. [Answer] Space within the pressure vessel is at a premium, so anything that doesn't need to be there (fuel transfer lines, some wiring harnesses, etc) is outside the pressure vessel, where space is basically free except for the slight hassle of maintenance. In addition, since there's a lot of things to maintain outside the spacecraft, there is a reasonable reason for having a maintenance terminal readily accessible outside. Kind of related, mass isn't cheap/free on a space craft. So there's an incentive to keep maintenance terminals and control systems as near to what they control as is practicable, to cut down on weight. Actual ship controls / controls on the command bridge would send commands to shipboard automation, which in turn sends commands to the individual control systems over several redundant links. The only way to take control of one of these vital systems is going to be going to the control system, put it in maintenance mode, and disconnecting from automation. One other reason for putting these things outside: they're dangerous. Taking manual control of maneuvering thrusters could allow you to destroy the entire ship, by, for ex, spinning the ship apart. This is really something that should only be touched in a very narrow set of situations. Like shipboard automation trying to kill everyone, or trying to diagnose why a thruster isn't firing. ]

[Question] [ If aliens came down to Earth and enslaved humanity, how long would it take to selectively breed the humans to make them more docile and less resistant to their alien captors? For example, if they just bred the most friendly and least aggressive humans, killing off the rebellious ones, how long would it take to make the humans domesticated, much like the way dogs and cats are? The aliens in this world are extremely long lived; the average lifespan is about 1,000-1,500 human years. The aliens' government is roughly based on imperial Rome. They invade other species' planets and either assimilate or kill and enslave them. Keeping slaves is not necessary to them as they have advanced artificial intelligence; keeping slaves is seen as a symbol of wealth and power, with only the elite owning slaves. [Answer] As previously stated humans could be very easily trained if taken from a very young age. On top of that any genetic influences could also probably be bred out within 10-20 generations. Experiments have been conducted with Silver foxes breeding the most aggressive and the most docile of each generation producing remarkably different temperaments as can be seen [here](https://www.youtube.com/watch?v=-L58NPPQ5eI). Similar experiments have also been conducted with rats with similar results. There is no reason to believe that humans would be any different. [Answer] One doesn't need to selectively breed humans for selecting character features. Education can go a long way, as it was proven by *the Romans: take the children of the aristocracy of a conquered people and raise them as Romans, then send them home.* (credits @Will for the italic text) Just take babies from their parents and grow them up to have good relationships with the alien masters. It will take 10-15 years, and the aliens will have friendly humans available, without the hassle of breeding them. Once the first generation has been raised, they can very well keep up the job almost on their own. [Answer] # Williams syndrome If they only want a few hundred thousand they might have all they need right away. There's a rare human disorder, Williams syndrome. Williams Syndrome is a rare condition (1/10,000 births) caused by the deletion of some genes on chromosome 7. When somebody checked which gene was most different in dogs versus wolves, and [they found it was WBSCR17](http://ngm.nationalgeographic.com/print/2011/03/taming-wild-animals/ratliff-text). The WBS in the name stands for “Williams-Beuren Syndrome” because the human version of the gene has been linked to the disorder. People with Williams Syndromes have short noses (compare to the short snout on domesticated foxes), smaller teeth (compare to smaller teeth in dogs vs. wolves), smaller brains etc People with Williams Syndrome are friendly, chatty and pathologically trusting. Many have learning difficulties but some have a fairly normal IQ, it doesn't help. They're still [pathologically trusting](https://www.theatlantic.com/health/archive/2014/05/going-to-work-with-williams-syndrome/361374/), as in they can barely conceive of someone not having the best possible intentions for them. There's been some reports that williams syndrome children are basically incapable of racism among other things. They tend to [get abused/molested at a much higher rate](https://www.npr.org/templates/story/story.php?storyId=126224885) than the general population. [](https://i.stack.imgur.com/Xyimd.jpg) If aliens arrived on earth and wanted to domesticate humans they could find an estimated 20,000 to 30,000 people in the United States alone already with williams syndrome. Probably a few hundred thousand from all around the world. There's various other health problems associated with the syndrome but selecting the healthiest individuals with near-normal IQ they could probably simply start a breeding program including a large fraction of Williams syndrome individuals and quickly (decades) have plenty of humans almost entirely incapable of believing that their alien masters have anything but the best intentions for them. [Answer] Biologically, humans are already domesticated. The theory is that we actually domesticated ourselves when we developed agriculture. The concept still has some controversy, but most of the arguments for human self-domestication stem from osteological analogies between the bones of ancient vs. modern humans, compared to those of other domesticated animals. For example, a serious injury in a modern human would not have been as serious for an ancient human, due to their bones actually being thicker. So an extraterrestrial species would not need to "domesticate" humans, unless they have their own definitions of what an intelligent domesticated species should be like (which is likely, if they are practicing slavery). Either way, I do not think any amount of genetic engineering will completely eliminate slave revolts. Most likely some kind of drugs or hormonal control would be needed, but the best option I think is simply through cultural change, like others have suggested here: kill all the parents and then create a new culture with the children. [Answer] The question really comes down to what the slaves would be doing. Bear in mind that many people already do fairly tedious jobs in return for a reasonable standard of living for themselves and their family. Historically (and still in many parts of the world) those jobs have often been dangerous. Even so, people have done those jobs because they didn't have a good alternative choice. Unless slavery is more dangerous than, say, mining in the 1700s, I don't see a massive drive to rebel. If slaves do not have particularly harsh duties and are basically just set tasks to keep their owners amused - playing music, sports, or whatever - then it's almost impossible to see them rebelling, and hence "domestication" is unnecessary. Hell, anyone who tries opposing the aliens is likely to be lynched by their fellow humans who quite enjoy their comfortable lives. This also makes me question why the aliens would bother to kill humans. They have AI, so robots can simply move troublemakers to internment camps. If the aliens are not kind masters though, some type of domestication will be necessary. It does not necessarily need to be bred in, of course. The aliens in [The Tripods](https://en.wikipedia.org/wiki/The_Tripods) used brain implants to keep their human slaves under control. I'm afraid this is a bit of a standard B-movie trope. See [Slave Race](http://tvtropes.org/pmwiki/pmwiki.php/Main/SlaveRace), or [Turned Against Their Masters](http://tvtropes.org/pmwiki/pmwiki.php/Main/TurnedAgainstTheirMasters) when some humans fight back later (as in *The Tripods*). You're going to have to do something rather special with this concept if you want to keep suspension of disbelief, otherwise you're likely to end up with just another 30s/40s pulp sci-fi pastiche. [Answer] I'll take a contrarian approach. It will take less than 30 years to domesticate humans. The invading aliens are technologically superior to such an extent that their technology is like magic to us. If they can travel interstellar distances, they have us beat in that same way that dogs cannot understand how our household technology works. The dry food arrives in either a paper or plastic bag. The wet food arrives in tin cans (not that they understand paper, plastic or tin). Humans cause the food to come out of the containers like magic. Water is always in the toilet, ready to drink. So the alien overlords have AI, unknowable materials science, near instantaneous surveillance and superior weaponry. Resistance is futile. Human science, engineering, and most learning will collapse because there is no point studying Einstein if he's just been proven wrong and we don't have the intermediate steps to get to whatever the aliens understand of physics. Again dogs can't understand refrigerators let along jet aircraft. Religious conservatives, the military, nationalists, the wealthy, elites and politicians will be killed during the invasion. Any survivors will commit suicide unable to understand the world they find themselves in. The human population will probably shrink by a least a billion, probably by 90%, possibly by 99%. That leaves 70 Million humans. Still probably too many if the Alien elite need only trophy humans for the status symbol. They probably only need a breeding population of 50,000 to 100,000 humans. The aliens could take the long view and allow humans to continue living in cities without culling the population. If the aliens allow human culture to continue, are generous with food, medical attention and shelter, there should be a flowering of human creative endeavours as humans have nothing else to do but create art, books, music, movies, theatre and entertainment. Bread and circuses. Humans will be left with art and sex as their only pastimes. By the time the children born on invasion day reach puberty (say 12-15) any "old-timers" notions of human resistance will have vanished. By the time those children's children hit puberty they'll be like the Eloi in HG Well's Time Machine. Life will be idyllic, simple and totally dependant on the mercy and good treatment of the alien overlords As a result of comments I note that "Einstein being proven wrong" is inaccurate in the same way that Einstein did not prove Newton wrong. However, Einstein did state that nothing can travel faster than the speed of light. So the aliens are either: 1. Interstellar travellers with warp/hyperspace/whatever FTL ships 2. Generation or Suspended animation ships travelling interstellar distances at slower than lightspeed 3. Interplanetary aliens that we cannot detect either from the outer solar system or cloaked in the inner solar system. All 3 scenarios significantly exceed our technology. And the most likely scenario is they've cracked FTL travel. They've also invaded and enslaved humanity. So the starting assumption is they kicked our asses. [Answer] I think the official dictionary definition is a good answer on it's own. "to tame (an animal), especially by generations of breeding, to live in close association with human beings as a pet or work animal and usually creating a dependency so that the animal loses its ability to live in the wild." Especially the latter part about creating a dependency. This could be done in different ways. One way would be as the series "V" did. Come to earth and "give" technology away. In the long term people will become depended of the technology. You could also tie it in with out current climate problems. These problems are created by the aliens. Slowly destroying our atmosphere, only to swoop in and save earth. Off course making us completely depended to them. After a 1000 years (Not really that long for the aliens) it will be the status quo for us humans, maybe we will even see them as our gods we need to obey. In short you first need to create obedience and after a lot of (human) generations make this the normal state of affairs. This however does not mean some humans will not bite if cornered. The time span will obviously depend heavily on the how you do it. It could take generations for the aliens or be instantly if you use some sort of brainwashing (As in the latest UFO computer game). Also the line between the humans being forced slaves and being domesticated is pretty gray for a while. [Answer] As intelligent and inquisitive creatures are conceived as a threat, the aliens might be unwilling to reveal to humans anything about their past. They might separate the adults from their children (as said earlier) and raise the children in a new society, letting them meet only with like-members. Part of the "domestication" process is controllig such information and creating the impression that humans and the aliens always lived side by side while humans lacked any notion of culture and technology. They might do that for every few genarations, if they realize humans became too inquisitive and are suspecting that there is more than meets the eye. For instance: humans would inquire where the aliens bring the food from, and why can't they get it by themselves? Why humans are confined to particular places unlike the free-roaing aliens? Why that human was reprimended for somethig he has done, and what wron did he do? There are numerous events in which humans would communicate and attempt at starting a rebel, and the aliens must keep an eye on. [Answer] I'd say if you want adult specimens asap with an explosive collar you would have enough to make them obey ofc you would have to blow 1 or 2 just to make an example. If you want fresh from baby stages it would take 1-2 generations remember our education is what makes most of our personalities if you teach them from little that defiance = pain they will obey willingly. To truly domesticate like you would do with an cow ... i believe it would be nearly impossible but this depends mostly how the aliens are (as a race) be it the most advanced goat in the universe ... if power runs out in the super goat-battle suit tonight we are going to eat goat soup (an example of an animal race going full alien). [Answer] As with any sort of livestock the results are not so much based on how they bred so much as which offspring are culled and which are chosen to breed new. Another aspect that is important is how they are trained and educated. The more they are taught to think creatively, and act independently the more likely they are to rebel. Think of the dog that acts out when it doesn't get its way. The difference here is that humans have far more developed brains than dogs or other livestock. They can learn new things, and be creative. These are traits that complicate domestication. If humans are treated as Equals or even just given free access to information and communication with others, some will eventually develop a desire to rebel, and fight back. However if information and learning is limited and controlled, normal brain development can be retarded and the ability to effectively coordinate can be diminished. Humans are not the most dangerous and top predator in the world because we are strong, but rather because we are smart and have access to tools that we can leverage to make us stronger. If you eliminate that ability to learn to work together effectively, you remove a big portion of the human race's strength. That said, how effective of a slave or pet would you have if you retard development of the ability to think, reason, and coordinate? Imagine if humans were reduced back to the basic abilities of the severely mentally challenged. Any race of alien that has the ability to do this, would likely be able to produce robotic type constructs that could handle any task far more effectively and with less error than a mentally hobbled human could. More likely the race is advanced enough to modify the human genome to reduce the incidence of independence, violence, and any other traits that the master race finds troublesome. But still I would expect that there would be some serious need to cull the herd pretty regularly to keep a properly restrained herd. [Answer] One look at slavery in the past will tell you humans have an inbred desire for freedom and thus will never be domesticated which is another word for slavery. ]

[Question] [ What scientifically would make it possible that certain large bodies of water be impassable while others that seem very similar are able to be navigated? This is not what I am attempting to do, but as an example say in some sort of alternate history no one discovered the Americas due simply to the fact that their vessels could not cross the Pacific or Atlantic Oceans. There were ships that could cross the Indian Ocean perhaps, but not the two that surround the 2 western continents. This would obviously be made possible by further future development, but say until the 1700s it was not. Is this at all possible? I'm not looking for an answer that they didn't know the continents were there, but rather there is no way they could have known because navigation across those two bodies of water was impossible once a certain distance from Europe, Africa, or Asia was reached. [Answer] **The winds** Very unfortunate wind patterns are going to make it very difficult, if not impossible to cross an ocean with sail ships, requiring a civilization to invent steam power or sufficiently advanced sailing techniques (yes, it is technically possible to sail against the wind) to cross the ocean. It is entirely possible for wind patterns to be permanent, for example the [westerlies](https://en.wikipedia.org/wiki/Westerlies), going only in one direction. That can make an ocean impassable, though this mechanism is direction sensitive. Permanent wind patterns can also isolate an entire continent, through a mechanism like the [polar easterlies](https://en.wikipedia.org/wiki/Polar_easterlies), caused by air sinking over the continent and subsequently move in any direction. Visualization of some of the permanent wind patterns on Earth: [](https://i.stack.imgur.com/bEXHw.png) [Answer] ## Shipworms They're real: <https://en.wikipedia.org/wiki/Teredo_navalis> and they'll eat through the hull of your wooden ship in a matter of weeks. Make them a little bigger, a little hungrier, and long crossings will be impossible. Even until quite recently a lot of ships were lost at sea, never seen or heard from again. The Titanic is unusual, not because she was lost, but because we know where and when and because there were actually survivors. Normally, even at that point, a ship lost at sea would set sail and just never turn up again. Your ships will go to sea and the shipworms will start eating. The hull will be gone before they see land again and long crossings become impossible, but as requested, later technology makes the crossings possible (though later than suggested): > > In 1878 it was discovered that creosote was an effective deterrent, though to work best it had to be applied to soft, resinous woods like pine; in order to work on harder woods such as oak, special care had to be taken to ensure the wood was completely permeated by the creosote...[snip]...The only permanent solution to attack by Teredo navalis, however, is to replace wood in submerged constructions with some other material. > > > or dragons, you can always have dragons. [Answer] Here's an interesting one: Bubbles would do it. Bubbles rising through water make the water less dense. Any ship will lose buoyancy and sink into the frothy water. A curtain of bubbles would be an impassible barrier. The problem is that it's hard to come up with a scientifically credible source of enough bubbling that could last for hundreds of years. If you're willing to hand-wave the details and plausibility, you could just say there's an underwater volcanic ridge spewing gas bubbles. Melting ice on the sea floor could also release bubbles, although that explanation is probably an even bigger stretch. It may be more plausible if you have occasional random patches of bubbles erupt. That would make sailing the area risky. People would simply stop sailing the danger zone after the first few ships were lost. [Answer] Europeans brought measles and smallpox to the Americas and an estimated 90% of the native population died. Now suppose that there had been a disease to which Europeans had no immunity.... In your world there is an island continent which it is almost impossible not to arrive at. The natives are friendly and compassionate. The water, however, is deadly. It contains a parasite which is like Cholera but even more deadly, to which the natives have acquired resistance. (In our world if you have blood group AB you are extremely resistant to cholera). Ships land, are welcomed, replenish their water. Then everyone becomes ill. Most die. There are too few survivors to crew a ship. Add to this, for the conscript sailors there is little desire to try to return. The natives are very friendly, and the women are beautiful. They have cheated death and found a paradise! So nobody returns and soon it is well known back home that this particular ocean is impassable. Attempts to prove otherwise will be rare and if made, the same fate will descend on the next expedition. [Answer] There are a few problems with early trans-atlantic voyages. For instance: * Preserving enough food is troublesome. Commercial refrigeration wasn't technically available [until 1755.](https://en.wikipedia.org/wiki/Refrigeration#Earliest_forms_of_cooling) Only [traditional techniques](https://en.wikipedia.org/wiki/Food_preservation) could be used to preserve food, and it's hard to say how much food to pack when traveling into the unknown. Famously, Christopher Columbus' first voyage had concerns about their food and water supplies lasting for a return voyage. The obvious solution is to simply stock more food and water, so this is a weaker solution. * Columbus (and those who came after him) benefited from the [sea currents in the Atlantic](http://media-2.web.britannica.com/eb-media/24/149024-004-B14614AA.jpg). This is why he was deposited in the Caribbean instead of what is now the US eastern seaboard; the water literally pulled his ship there. If the sea currents were incorrect, then it would prevent many ships from effectively traversing the sea in question. If the currents were not helping, the voyage by sail could be impossible. Some other factors to consider in general navigation: * Hurricanes / Monsoons could easily stop and destroy ships from crossing a particular bit of ocean. Of course, the sea in question would have to have some method of developing regular, intense storms. * Heavy Tectonic Activity could make strong waves, and a varying sea floor depth could cause these waves to become tsunamis. Obviously, the sea floor rising would have to form [atoll-like](https://en.wikipedia.org/wiki/Atoll) structures or otherwise possess very shallow seas next to very deep seas for these large waves to form dangerous tsunamis. (A tsunami at sea is actually a very long, but very gentle, wave.) * Sea Ice can cause a sea to become very dangerous, especially if the sea ice shifts and changes very frequently. The frequent change would be required to prevent people from simply walking along the surface, certainly much faster than the [arctic does](https://youtu.be/6j8SGs_gnFk). * [Fata Morgana](https://en.wikipedia.org/wiki/Fata_Morgana_%28mirage%29) can lead sailors deeper into the ocean, thinking that they've finally seen the land their looking for. These can come from ice bergs or other oceanic bodies. * Severe temperatures can prevent people from crossing a sea. It could be simply too cold or hot, especially if the people cannot gain access to proper insulation. * Predators could prevent ships from crossing. If [Dunkleosteus](http://www.prehistoric-wildlife.com/images/species/d/dunkleosteus-size.jpg) or other large sea predator was still around, it could try to take a bite out of a columbian-era ship. For scale, consider the following: [](https://i.stack.imgur.com/D0abd.png) and the fact that the [Niña was ~15.24 m (~50 ft)](https://en.wikipedia.org/wiki/Ni%C3%B1a), somewhere in the low end of Megalodon range. A megalodon-like creature could try to defend its territory, and possibly be like a dunkleosteus and simply be used to chewing on hard things. [Answer] **Limit your sailor's navigation abilities** Although it would not make navigation fully impossible, you could consider giving your world very limited visible stars, and weak (or no) magnetic fields. The primary tools for determining absolute position in the 17th century were the [astrolabe](https://en.wikipedia.org/wiki/Mariner's_astrolabe) and the magnetic compass. Without reference stars or a magnetic field, it would be difficult to determine absolute position on long voyages. As such, if your world only has one visible star, and that star is only visible in the northern hemisphere, oceanic navigation in the southern hemisphere would be risky at best. However, ships at this time did navigate by measuring current and wind speed, and calculating true velocity from there. The slight error associated with these methods would be acceptable when traveling from port to port, but would compound unacceptably over longer distances, like your version of the trans-atlantic voyage. Thus, you could create a series of small islands, or other recognizable landmarks (watermarks?), in oceans you want transversable. Maybe some areas are constantly rainy, or have strange currents. The landmarks would allow sailors to re-calibrate their relative position measurements, and navigate effectively. [Answer] I'd like to point out that the [Northwest Passage](https://en.wikipedia.org/wiki/Northwest_Passage) has in fact been non-navigable until very recently, which affects global comerce and history, as ships have to go a longer route instead. The availability of "other routes" is another issue with your premise. The non-navigability of some region doesn't affect *all* approaches to your forbidden contenent. Another idea for you is the phenomena of [rogue waves](https://en.wikipedia.org/wiki/Rogue_wave) the specific geology and weather patterns could make them more prevalent in some region. You could also have things like hurricanes that are *always* in the way. [Answer] The question really relates to why the Indian Ocean and such waters was travelled before the Atlantic and the Pacific, as no ocean is actually impassable. The answer lies in the technology being used to navigate the waters. In early marine travel ships would stay close to land for the following reasons 1) Poor ability to sail into the wind, and the risk of becoming becalmed. Thus there existed the real possibility of becoming marooned in the middle of an ocean unable to return to land. This fear was particularly heightened by the poor understanding of how winds were generated (usually attributed to gods) 2) The need to seek shelter in storms. Early boats were not capable of withstanding severe storms and required to be sheltered in severe weather. 3) Limited navigation - limited ability to tell direction, no ability to tell longitude. Travelling in unknown waters far from land meant having no idea where you were, and almost no idea how to get back. The Indian Ocean is thus easy to navigate by staying close to the shoreline from Africa to Indonesia, and thus this is how it was done. Australia was visited only accidentally through being lost. An Atlantic crossing requires a leap of faith in very risky waters. Columbus achieved it through luck, and a combination of delusion and information gathered from the fishing community. It is possible the Portuguese fishermen where regularly travelling to the West Atlantic. This knowledge being built up over centuries of experience and the quest for wealth. The Vikings achieved it by travelling in small steps across the far north. This involved expertise in travelling through such waters that only the Vikings possessed, and reliance on rowing as well as sail. The North Pacific was not crossed as there was no corresponding culture to the Vikings capable of cold sea navigation. The central Pacific was navigated, however, by the Polynesians. This was done gradually over centuries, driven by population pressures, by people expert in navigating such areas, capable of living off the sea, and by using rowing as the primary means of locomotion. It was done in a step-wise manner, from island to island looking for tell-tale cloud formations as navigation. There was likely significant loss of life in such travels. So the navigability of the world's oceans is an expression of the culture and technology of the people travelling, with the short answer that it is relative easy to travel along the coast in warm climates. [Answer] **Fast continental drift** could create a line of very active **volcanoes** across the entire seabed. The heat, noxious fumes, completely opaque steam and possibly extreme storms would make it difficult to navigate with anything less than space-age technology - an airtight vessel, air recycling, and some combination of a very fast engine, extreme thermal insulation, and cooling to keep the temperature bearable for the puny humans. Alternatively, use long-range hydraulics and telephony for the first uncrewed mission to Manhattan. [Answer] Thick plant-life coverage, sargassum on steroids. Too much drag to go through on sail power... ... until some genius figures out that they contain an oil that can be extracted on the spot and used in the boiler of a steam engine, so ships are essentially eating their way through the algae layer (with a chainsaw on the bow and scoops on the sides). Some centuries later, the ocean has become empty, and the Age of Sail commences. [Answer] * As a couple of answers have already said: because sea monsters. * There is a society (country) on the other side of the pond (i.e., in your example, in the Americas).  They are very secretive — they have made no attempt to communicate with outsiders, and they *really* don't like to be discovered.  So much so that any ships that make it to their shores are destroyed, or at least captured and not allowed to depart. If your explorers have world-wide communications (i.e., the ability to contact home base by radio and report what's happening), then suppose that the secretive country is so technologically advanced that they have submarines, stealth aircraft, drones, cruise missiles, lasers and/or satellite-based weapon systems, and they destroy all approaching foreign vessels before they know that they're under attack. * Combine the above and you get merpeople, who live underwater and perceive ships as trespassers.  When they detect approaching foreign vessels, they destroy them (either killing or assimilating the crew). * A slightly more mundane possibility is [maelstroms](http://webecoist.momtastic.com/2009/07/24/10-magnificent-maelstroms-and-destructive-whirlpools).  These are [whirlpools](https://en.wikipedia.org/wiki/Whirlpool)/[vortices](https://en.wikipedia.org/wiki/Vortex) in the open sea/ocean.  It looks like these are comparable to underwater tornados, and can be very destructive.  It's not clear how these could make an entire ocean impassable, but maybe anomalies in the ocean floor (underwater volcanos?) could create a chain of maelstroms that would be difficult to navigate without overhead imagery. I thought I remembered reading about such a maelstrom (maybe 10 meters in diameter) in open or at least semi-open water (e.g., a bay, harbor, channel or strait).  I cannot now find the page I remember; in particular, I cannot find any very impressive video on YouTube.  Most of the videos I found showed whirlpools that were + small (approximately 1 meter) or indeterminate size (no reference scale), + in closed bodies of waters (e.g., lakes), and/or + manmade, [this](https://www.youtube.com/watch?v=eqROBTVgL6A) and [this](https://www.youtube.com/watch?v=wSVPgK-UAVA) were the best videos I could find. * In the course of researching the above, I came across references to vents in the ocean floor spewing sulfur-laden gasses, and underwater volcanos similarly emitting toxic fumes.  If there were enough of these (e.g., a chain of volcanos) close enough to the surface that the gas could reach the surface without being absorbed by the water, they could produce a region of poisoned air that would be invisible.  Sailors wouldn't know what had hit them until it was too late.  But I see other people have already discussed this notion. [Answer] Disease. There's a chain of islands across the ocean, they are inhabited by seagoing birds. (The birds only live there because of their nesting habits, they can't survive where ground predators are a threat.) The birds harbor a disease that's extremely lethal to humans. Rather than be scared of moving things (predators) the birds are scared of large land masses where predators live. Thus the birds have no problem with landing on a passing ship. While it's probably not 100% lethal the survivors can't operate the ship and the ship very well might founder while people are sick even if they would later recover. [Answer] I was going to mention something similar to a previous answer. Large aggressive sea creatures like giant squid, prehistoric predators and the like would cause issues. After all, crazy monsters were drawn on early maps! Maybe, too, shipbuilding technology could be limited. Weak or sick trees would supply poor timber, and without flax or similar there would be no sails. An outbreak of a virulent disease or fungus could destroy floral life. [Answer] **Rogue waves** (also known as ***freak waves, monster waves, episodic waves, killer waves, extreme waves,*** and ***abnormal waves***) are large, unexpected and suddenly appearing surface waves that can be extremely dangerous, even to large ships such as modern ocean liners. On earth such rogue waves present considerable danger for several reasons: they are rare, unpredictable, may appear suddenly or without warning, and can impact with tremendous force. A 12-metre (39 ft) wave in the usual "linear" model would have a breaking force of 6 metric tons per square metre [t/m2] (8.5 psi). Although modern ships are designed to tolerate a breaking wave of 15 t/m2 (21 psi), a rogue wave can dwarf both of these figures with a breaking force of 100 t/m2 (140 psi). In oceanography, rogue waves are more precisely defined as waves whose height is more than twice the significant wave height (Hs or SWH), which is itself defined as the mean of the largest third of waves in a wave record. Therefore, rogue waves are not necessarily the biggest waves found on the water; they are, rather, unusually large waves for a given sea state. Rogue waves seem not to have a single distinct cause, but occur where physical factors such as high winds and strong currents cause waves to merge to create a single exceptionally large wave. Once considered mythical and lacking hard evidence for their existence, rogue waves are now proven to exist and known to be a natural ocean phenomenon. Eyewitness accounts from mariners and damage inflicted on ships have long suggested they occurred. The first scientific evidence of the existence of rogue waves came with the recording of a rogue wave by the Gorm platform in the central North Sea in 1984. A stand-out wave was detected with a wave height of 11 metres (36 ft) in a relatively low sea state. However, the wave that caught the attention of the scientific community was the digital measurement of the "Draupner wave", a rogue wave at the Draupner platform in the North Sea on January 1, 1995, with a maximum wave height of 25.6 metres (84 ft) (peak elevation of 18.5 metres [61 ft]). During that event, minor damage was also inflicted on the platform, far above sea level, confirming that the reading was valid. ***Thus, if rogue waves were to occur more commonly in certain oceans rather than others, they scientifically would make it possible that certain large bodies of water would be impassable while others that seem very similar would be able to be navigated.*** Additionally, since the research is on going on modern earth, their cause could reasonably remain a bit of a natural mystery with several contradictory theories which is logical since they has not been fully solved, nor completely understood our own modern scientific community. [Answer] Water density/temperature. Warmer water has a lower density than colder water. [Salt water has a different density to fresh.](http://www.windows2universe.org/earth/Water/density.html) This is a real world problem, which is why ships have the [plimsoll line](http://oceanservice.noaa.gov/facts/plimsoll-line.html) that indicates differences between climates. Now imagine if no one figured this out. (maybe for the sake of drama, you could increase the margin of error). They'd set sail, hit some warmer and lower density water and - because they're heavily laden for exploration - sink. [Answer] I would go with a round continent like Antarctica which is so situated that it develops a similar [Antarctic Circumpolar Current.](https://en.wikipedia.org/wiki/Antarctic_Circumpolar_Current) Because it never plows into a continent, its speed is phenomenal. It's that current rising over sea mounts at the tips of South America and South Africa that makes those capes so challenging. It wouldn't have to be at the poles, a circular continent at the equator would develop a circular current from the current on one side flowing north and the the current on the other side flowing south, Just like the currents along the Americas or Australia. It's not inconceivable that such a current could actually deflect ships with pre-1700 analog tech completely around the continent without the mariners being aware of it. Certainly if they hit it from the north or south, they wouldn't have the ability to measure longitude and so wouldn't know they were being deflected East or West. A semi-sunken continent like North America in the [Permian Period](https://upload.wikimedia.org/wikipedia/commons/1/1d/260Marect.jpg) (see the area in the Northwest of the map) with a vast shallow continental shelf could form vast coral reefs much like those South of Java and around Australia that could be hundreds of miles across. Such reef structures lay less than 2-3 meters under the surface most of the time and form vast mazes of barely navigable water channels. Add in strong tides (a large moon would help) changing water levels, plus the powerful circulating current and you've got a pretty efficient ship shredder. All the more so because they severely restrict the ability of sailing ships to tack enough to make much headway. The reef system could also effectively hide the continent by trapping debris washed into the sea e.g. tree limbs such that even if a ship did find the reefs, they would see evidence of a larger land mass. Sea mounts could deflect the current in spots towards the reefs as well. Likely, the trade winds would as well. With the right combination of tides, currents and storm surge, a ship could sail into the heart of the reef and find itself trapped when the water levels dropped again. If the continent is tropical to temperate, you would hurricanes and tropical storms several months of the year which would pile up huge waves when they blew against the circulating current. Ships would stall out just as they do on the southern capes with the wind blowing them one way and the current going the other, so the ships just stay in the same place and get hammered to pieces. Or until they're blown up onto the reefs. Not until the mariners developed the clocks needed to measure longitude could they reliably figure out the proper way to approach the continent. [Answer] # Why navigate the Atlantic? The reason was economic. Before the 1200's, almost anything in the Asia's far East (i.e. after Persia) was a complete mystery to Europeans. There were just a very few vague, scarce and sparse information, rumors and legends. That, of course, until Marco Polo actually traveled to there\* departing from Italy, getting back alive (24 years later - it was a looooooong journey), and being able to tell his memories to a friend who decided to write'em down in a book and publish it. \* - Well, he claimed that he went there, but [there is some doubt and debate about that being or not true.](https://en.wikipedia.org/wiki/Marco_Polo#Debate) Marco Polo described a rich Empire and culture in the far, far away East, called Cathay (which is China). He also described what he knew about central Asia, India, Mongolia, Cipango (Japan) and Burma (present day Myanmar). Goods were already traded indirectly between Europe and China, slowly passing through a long chain of intermediary merchants from many different countries, cultures and languages, such as byzantines, turks, berbers, egyptians, arabians, armenians, parthisans, persians, indians, tibetans, mongols and chineses. Of course, with that such long chain, any goods coming from India or China had a very high price when it eventually reached Europe some years later, because all of the intermediaries would profit from it. Merchants in the Europe, knew that the goods coming from China and India (specially China's silk and India's spice) accumulated a very high price in the way, so if someone could somehow go there and bring back goods without relying in so many intermediaries, they could sell them at lower prices and higher profits. With the fall of Constantinople, in 1453, the trade got harder. This happened because the Muslim cultures that dominated Asia's West, Central Asia and North Africa were very hostile to the Christian cultures in Europe (many of them, catholic crusaders). With the fall of Constantinople to the Muslim Ottomans, the situation just got worse, since the last remaining land route between Europe and Asia's far East was closed, without any sea route being known. The result was that India's and China's goods which already were rare and expensive in Europe, became still more rare and expensive. So, Europeans had very good reasons to try to reach India and China through the seas. Anybody who could manage to do that, would open a highly profitable trade route with no, or perhaps just a very few, intermediaries. # Which countries sailed or not sailed and why? Opening new sea routes in the Atlantic to the far East would be very expensive on itself and demand a level of organization and financing that only kings could have. Which states could provide that? * The Holy Roman Empire was a mess, with all of his internal states struggling and warring under a puppet Emperor which actually lacked power. * Italy was the source of a lot of skilled sailors, but was a mix of small disputing states and city-states, so no state could finance such thing. * The Pope already had enough problems to worry about, including Muslims and heretic Christians. * East European states lacked enough organization and navigation skills, and some of them already had problems with the Ottomans. * England and France were warring during most of the XV century, wars which included Flanders, Burgundy and Austria, so all of them had too many domestic problems to worry about. Also, they already had fairly strong economies, so investing resources in navigating the Atlantic to reach India would be a silly way to waste money that they could instead invest in something else much more economically plausible. * Denmark, scandinavian states and Iceland were just too far away in the North to have any interest in navigating warmer waters. * The Muslims were not interested in sea trade through the Atlantic, because they already effectively traded by land or by navigating the Mediterrenean Sea or the Indic Ocean, and they had no interest in trading with European northern states. So, navigating the Atlantic would be pointless for them. * Far East cultures had no reasons to try to navigate the seas to reach Europe. It was damn too far away, and they already had many people to trade nearby either by land or sea. Also they knew almost nothing about Europe, and most of what they actually knew, was obtained from Persian and Arabic sources, which depicted Christian Europe very negatively. * Sub-saharian cultures were far too primitive and underdeveloped to think anything about navigating the Atlantic. The american indians also were far too primitive and had no reason to cross the Atlantic in the other way and reach Africa or Europe. * This leaves only two suitable countries: Portugal and Spain. During the XV century, Portugal and Spain figthed the muslim kingdom of Granada during the Reconquista war. Portugal finished its part of the war first, so they got a head start. With the war end, Portugal needed some sort of economic activity which would ensure high profit for them, and they already were skilled sailors. Portugal started to explore Africa's coast in 1418. Their sailing skills leaded to the invention of the caravel, a type of seaship who could sail further and faster than the other existent seaships at the time and could even sail against the wind. Spain was decided to not be kept behind Portugal, so they started to quickly develop their navigation. However, they were still struggling in war against the moorish kingdom Granada. # Crossing the Atlantic And then, in 1486, a man called [Cristoforo Colombo](https://en.wikipedia.org/wiki/Christopher_Columbus) met the Spanish king and the Spanish queen with a crazy lunatic idea: he wanted to reach Indies by sailing west around the globe instead of sailing around Africa. The Atlantic Ocean was a formidable obstacle back in the XV century. [People already knew that the world was a spheric body](http://www.asa3.org/ASA/topics/history/1997Russell.html), but Columbus believed that the distance between the Canary Islands to the Japan, by sailing west, should be roughly 3700 km, but in fact it is 12500 km - i.e. he severely underestimated the size of the globe. Also, he thought that Japan should be nearer to the equator and be as large as China. Most "main-stream" navigators would not venture in such voyage because they (rightly) thought that Earth was much larger than that, so that such voyage would be a crazy idea - and they would be right if there was no American Continent in the way and the Atlantic and Pacific Oceans just formed a very large ocean. Columbus already talked to Portugal's king in 1485, but his idea was rejected as being unrealistic, since the king's experts asserted that the Earth should be much larger than what Colombo calculated (and it is). Spain also initially rejected Columbus's idea in 1486, but the king decided to keep he around to avoid him going away and telling his idea to someone else. Also, in 1488, Portugal reached the Cape of Good Hope and was definitely not interested anymore in trying to sail west. Portugal was dedicated into the task of reaching India by circumnavigating Africa and nobody else was seriously competing with them yet. In January of 1492, Spain could finally dismiss Granada once and for all, and then the king could finally dedicate all the efforts into navigation. Columbus continually kept lobbying the Spanish court for all those years, and when he was just finally giving up and leaving, in April, the spanish king decided to give Columbus' idea a try. It was really a very far-fetched crazy idea, but if he was correct, Spain would quickly profit and be able to compete with Portugal, and since Spain's king knew that Columbus was a very skilled sailor, this could not be as crazy as it seemed to be afterall. So, only seven months after expelling the Moors, Spain sent Columbus in his sea journey to the west. He departed from Spain in August, and from the Canary Islands (the last then-know piece of land in his journey), in September. After five weeks sailing unknown waters to the west, he landed in the other side of the ocean visiting islands that today are parts of Bahamas, Cuba and Haiti. Portugal reached India in 1498, but landed in South America in 1500 and also started to explore the american continent. France, England and Flanders (Netherlands) joined the race somewhat late to the party. # Ok, how to make that not happen? There are many points in the history around the last years of the XV century that if just a few things were different, the american continent would be only discovered much later, possibly well into the 1700's, possibly even after Australia's discovery. In fact, its discovery is much more a product of random luck and fortuitous economic situation than anything else. * If Portugal reached India before Columbus reached America, it is possible that no one (including Spain monarchs) would seriously believe the possibility of navigating to the west far away enough to reach land for some long time. Specially since they already knew at the time that Earth was too large for that being viable. Putting all the efforts into navigating around Africa would be economically safer. * What would happen if Columbus' caravel were hit by a hurricane and perished to never be seen again? Or if they all were just killed by american indians? * What if Spain monarchs just dismissed Columbus the same way as Portugal did? * What if Columbus never born to start with? * What if Portugal and Spain had some other economic interest (and perhaps didn't invented the caravel afterall)? Or if Granada resisted harder? Or if the Spanish monarchs just suddenly died in an accident and a succession dispute began? * What if the Ottomans decided to earn gold by seriously trading with some European nations instead of keeping ressenting anti-crusader feelings? * What if Egypt decided to earn gold by routing India's goods from the Red Sea to the Mediterranean Sea, making both the ideas of sailing west the Atlantic or around Africa too costly, too dangerous and too time-consuming? * What if Marco Polo never came back to Europe? * What if Constantinople resisted longer? With that, the reason to not cross the Atlantic would be just: "**Because it is too dangerous, too expensive and is very unlikely to be worth anything. Further, nobody ever heard of anything beyond those seas and have no reason to believe that India or Japan are anywhere near in that direction, so traveling that way is absolutely pointless.**" Note that those changes are very simple, plausible and mundane, so there is no need to have supersized shipworms, nor dragons or sensational creatures, nor crazy climatic phenomena, nor crazy geographic or geologic features, nor strange geomagnetic or astronomic phenomena, nor specially unfavourable and unluckily positioned wind, sea-currents patterns or reefs, nor anything severely different than what history was until that point. # What about crossing the Pacific instead? As soon as the news about crossing the Atlantic and what was found there spread into Europe, cartographers started to debate about what they actually were, and concluded correctly in the first years of the XVI century that those new lands could not be by any means parts of Asia, and they were in fact an entire new continent. What made the Pacific be eventually crossed is the fact that the discovery of the Americas sparked the interest to actually circumnavigate the globe and more importantly, perhaps discover some other unknown continents or profitable trade routes. The first circumnavigation of the globe was completed in 1522, after a long and dramatic 3-years journey which killed most of the crew and left some of them in the way, [with just a few survivors with bad health being able to complete it (18 out of 237)](https://en.wikipedia.org/wiki/Ferdinand_Magellan#Survivors). Only 30 years before (in 1492), the idea of sailing west the Atlantic were considered lunatic, but now the globe could be circumnavigated exactly in that way. If nobody crossed the Atlantic, crossing the Pacific sailing westward would have no sense. Crossing it from Asia eastward, was already pointless: "**There is nothing valuable out there, just a few small and sparse worthless islands inhabited by primitive people**". So even if a few people from polynesian islands actually reached the american continent and could come back to their homes, they probably won't be able to spread the news efficiently, and in the best possibility, it eventually would be just another strange fantasy legend in the folklore of a primitive tribe from a remote island that nobody in the civilized world would care to hear about. So, with the discovery of the Americas, sailors started to fearless navigate into the open ocean instead of just navigating around known coasts. With that, many remote islands around the world were discovered and charted, and it is unlikely that they would be anytime soon if the discovery of the Americas was further delayed. [Answer] One more for the list - high energy particles. The earths magnetic field precesses and occasionally (in geological time) "flips". That means for long periods of time (by human standards) the magnetic poles may be under any given large area of ocean. (This wouldn't have to be close to a frozen polar area as it is on earth. For example, the poles might not freeze on this planet due to currents or global temperature, the axis of rotation may be greatly inclined, or the magnetic axis is different from the rotational axis). So suppose a strong, not weak, magnetic field. You now have your magnetic pole under some specific large area of the ocean for a few tens or hundred thousand years. Unfortunately this area is naturally where the ships would navigate. The stellar environment includes fierce radiation of charged particles which is somewhat focussed and drawn to the surface over a wide area, rather than diverted by this pole, and... voila, lethal ocean passage, if you happen to need a few months to cross it. The effect would be increased if either, your species is quite vulnerable, or other mechanisms prevent things like ozone or whatever else protects us humans. Perhaps some aquatic life has evolved to produce ozone-destroying gases in modest concentration as well (perhaps because they photosynthesise or use the radiation, or it kills their parasites or at highish levels triggers mating behaviour since this is when food will exist as microorganisms take up the high energy levels, so they evolved this over time as a way to increase their energy source/intake). [Answer] Ice! If there was an ice shelf surrounding a Continent like at the poles. The pack ice over North America has only just unfrozen enough in the last few decades to allow shipping traffic. For a long time everyone was looking for the fabled North West passage. [Answer] Late to the party: Make them impassable due to surprising consequences of active volcanic activity. Vigorous [bubble formation lowers the sea density to sink boats](https://www.newscientist.com/article/dn1350-bubbling-seas-can-sink-ships/) (especially if "roiling" is a word you like to use to describe seas) and/or [limnic (poisonous gas) eruptions](https://en.wikipedia.org/wiki/Limnic_eruption) would kill entire crews (and render the local sealife unsafe to eat). Decide the [midatlantic ridge](https://en.wikipedia.org/wiki/Mid-Atlantic_Ridge) and [other ridges](https://en.wikipedia.org/wiki/File:World_Distribution_of_Mid-Oceanic_Ridges.gif) have been actively [spewing](https://en.wikipedia.org/wiki/Volcano#Volcanic_gases) megatons of sulfur dioxide ($\mathrm{SO}\_2$), hydrogen chloride (HCl), and hydrogen fluoride (HF). [Answer] We have walked on the moon because we had the motivation to do so and the technology to transport people through a hostile environment with sufficient resources to provide food and comfort for their journey. Possible reasons are therefore A lack of motivation. The Dutch visited the West Coast of Australia, Tasmania and even New Zealand long before the English but had no desire to visit regularly or settle here. A lack of technology (either ship building or navigational), e.g. unable to build a ship big enough to contain sufficient crew to man it and the resources to sustain them, an inability to navigate out of sight of land etc. The hostility of the environment e.g. prevailing winds and currents, sea worms, coral reefs, availability of food and water along the route. Good luck! [Answer] An underwater landscape with prominent shoals and underwater features that direct the planet's tides in powerful and unpredictable ways. Most of the world's oceans are fairly deep, in the high hundreds to low thousands of feet. This depth acts as a buffer to the movement of surface layers due to weather and tides; there is *so much* water under what's being moved around by the moon and winds that in the absence of major, acute disturbing forces like a storm front, the energy dissipates fairly quickly into relatively calm rollers. However, what if the Atlantic Ocean had significant regions that were shallow enough to have little or nothing below the "thermocline" of water actively warmed by the sun? First off, the aggregate energy in the water would be much higher, because the average ocean temperature would be warmer. Second, the volume of water in the oceans would be much less, and therefore tidal movements caused by the moon's gravitational pull would be relatively major, causing entire land masses to appear and disappear under the water. Finally, irregularities in the ocean floor, because they're in the tidal zones, would cause much more treacherous currents and waves that could swamp or even break ships caught in them at the wrong time. A large enough swath of this kind of water, and it might be impractical to try to navigate it. The extreme case of such a planet is shown in *Interstellar*; the first planet, closest to the black hole Gargantua, is a water world dominated by a shallow sea, only knee to hip deep... except for massive thousand-foot waves scouring the surface, generated by the black hole's massive pull. Nothing in our own Earth's neighborhood has that kind of effect on the world's oceans, but maybe if Jupiter were a little closer, and Earth orbited Jupiter closely enough that its gravity were more powerful than the moon's (our own moon can't get too much closer or be too much bigger without gravitational tides tearing it apart), then we might see tides too strong to be navigable anywhere over a continental shelf. A shallow ocean over a very tectonically fragmented floor would produce a labyrinth of volcanic ridges, sandbars and reefs that would keep pace with erosion and present a major navigational hazard to any ship large enough to carry the necessary crew and supplies to traverse that great a distance. [Answer] Sea monsters are a good possibility in deep oceans. Some of the planet's oceans are very deep and very wide. And some are shallow and narrow. Huge and highly intelligent beings live in the deep oceans because they dive very deep to feed like sperm whales. Like sperm whales, they are rarely found in shallow continental shelves. Some time before a society of fishermen and whalers expanded along all the coasts of the oceans, setting up villages on islands. They rapidly killed off all the shallow water whales. And then, where the continental shelf was narrow, they found a deep water island to use as a base to hunt deep water whales. Unfortunately for them, some of the deep water whales they preyed on were the sperm whale equivalents, as intelligent as humans and with human like language ability to talk about this new threat and discuss it and pass the news all around the world from one deep water ocean to the next. And eventually the sperm whale equivalents all around the world made the decision to strike back. The central council order was given to attack all ships where ever they were found. So they smashed the whaling ships from the whaling island and sank them. The islanders soon gave up whaling and restricted themselves to fishing the shallow waters near the island and even raising crops on land. Meanwhile coastal traders were building bigger and better ships to sail farther and farther. Instead of goods being shipped in short trips and passed from one trader to the next, they started making long coastal voyages for thousands of miles. Eventually some merchants noted that the charts showed that many voyages went the long way around the coasts of the continents and that sailing straight across the deep oceans would shorten the trips unless they found unknown continents. So exploring expeditions were sent out to cross the deep oceans directly. And after the expeditions passed beyond the continental shelves they were soon detected by some of the very numerous sperm whale equivalents and attacked and sent to the bottom of the sea. And so all the expeditions sent to cross the deep oceans disappeared without a trace or any clue to what happened to them. And so the sailors of that world always sail along the coasts and go the long way around the borders of continents and never know what islands or continents may be in the middle of the deep water oceans. At least until the sperm whale equivalents eventually forget about being hunted and the order to attack all ships, or until the land people develop iron hulled steamships capable of resisting attacks by the sperm whale equivalents. ]

[Question] [ Imagine a high-fantasy magic world where magic has the place of a science. Noble/rare metals – such as silver, gold, platinum – have the ability to conduct magic energy, which is commonly used in all areas of life (imagine, for comparison, a world like ours where all energy wires must be made of gold). So, in this world, what can be used as money? I'm assuming that there is no way people would use things like gold coins, since gold is always required for practical use. [Answer] # Manacoin Manacoin (abbreviated as *mc*) is an ethereal currency that only exists as shared thoughts in the astral plane. Everyone can create astral "wallets" to store manacoins. Wallets have names, which can be used to put money into them, and activation words, which are used to take money from them. A wallet can be tapped by anyone who knows its activation word, so be careful and keep your words secret - but do let people know your wallet's name so they can transfer to it. To make payments with manacoin, use a cantrip to state you are moving a given amount of money from one of your wallets to someone else's wallet, identifying both the giving and receiving wallets by name. The cantrip will feed this information to an ethereal monster, of a species called "chainblock". Chainblocks eat all information sent to them. When they have eaten enough they die in an explosion, after which the digested knowledge is accessible to anyone who is capable of accessing the astral plane (a broadbelt link is recommended), and the most recent manacoin transfers are present in that knowledge. Chainblocks can only eat so much, though, and your cantrip is competing for stomach space with everyone else's, so you my have to wait for a few blasts until you find your transaction. If you are in a hurry you can include more manacoins in your cantrip, to fatten a chainblock beast faster. Last but not least - manacoins are made of the chainblock beasts' scales. Everyone can have a go at the exploded beasts' scales to coin new manacoins. However, only some people manage to do so whenever a beast explodes. It seems like chainblocks are evolving into a form which is ever less scaly, so it takes ever more powerful spells to get the same amount of manacoin per dead beast. At some point it won't be possible to mine for new manacoins. This, along with the fact that no empire has been able to completely regulate it, and its high demand in the forbidden markets, has caused the value of manacoin to soar in the last few years. [Answer] Well... money. What value has that piece of paper you call $100? What value has that piece of paper you call a check? Exactly what you want it to have. If you're asking what supports the value of said note then, it also can be anything. Maple syrup. Choco beans. The value of gold in ye olde goode times was not derived from its abilities but due to its rarity. Hence platinum and palladium that cost more. If this is high fantasy then the ink for a magic picture maker can be the most valuable thing. Also drugs. Antimagicorbs - which can be fun because you don't need to have so many. Because there won't be many wizards that would like to check your statement. [Answer] Modern currencies are very rarely backed up by any physical stuff. Tying paper currency to metallic wealth is not the guarantee of stability that people often think it is. See, you actually want to be able to control money supply in a society. Over time, as your economy grows, people start using money more - this is V, the money velocity. As V goes up, demand for currency goes up, and if you don't start increasing the money supply (the actual number of notes in circulation), your economy can start to crunch. This is in part why modern economists insist that a little inflation is essential for healthy economy growth. So as your economy grows, you have to print more paper money. Many gold-based currencies were able to pull this off by simply changing the amount of gold that a single bill represents: that way, money supply can go up even as gold supply stays the same. But this is not a very good setup. First of all, what's the point of tying the value of your currency to a useless yellow metal if you're going to keep the discretion to be able to change the money supply at will? You might as well have pure paper money at that right. Second, the value of gold itself has historically never been very stable, so this causes additional unnecessary problems. Finally, in our world (not your fantasy world), we end up spending vast resources and committing enormous environmental atrocities harvesting a shiny yellow metal in quantities that vastly exceed industrial (utility) demand. In your world, this would be an even worse problem, because demand for gold as currency would put the squeeze on demand for gold as a magical input. For superstitious reasons, it took a long time for many of the world's major economies to drop the gold standard, but ultimately it's worked out fine. Yes, there are governments that go nuts and print too much paper, but that used to happen anyway with the gold standard. Remember that the amount of gold a piece of paper is worth has to always be flexible to allow economy growth, unless you plan on mining tons and tons of new gold all the time, and so as long as any currency requires some type of government adjustment there is the same potential for bad decision making - so you might as well not tie it to a precious metal at all. [Answer] Having a commodity currency where the commodity has a practical use is actually a pretty good idea. The problem with precious metals like gold and silver which had little practical use (besides jewelry) during the time they were used as currency is that their prices are highly volatile. There were several global and local economic crisis' in the past 1000 years which were caused by sudden influx or efflux of gold or silver. When someone discovered a new gold mine nearby, that was actually bad news. It meant that some of your wealth is now being redistribute to the one who controls that mine. On the other hand, when there is an actual demand for a commodity, then the value of that commodity will be stabilized by that demand. It can not become too valuable (deflation), because people will riot before that happens. It can not become totally worthless (inflation), because people will keep consuming it. Also, obtaining a pure currency commodity is essentially a pointless endeavor. Over the course of world history, countless wars were fought, whole countries were enslaved and tremendous economical resources were invested just to obtain gold and silver. And what was the point? What net improvement in quality of life has that gold and silver generated for humanity as a whole? None at all. It just redistributed wealth to those who acquired it, but it didn't create any. On the other hand, if you need to work a few hundred people to death in order to obtain the resources which actually allows an improvement in the quality of life of millions of people, then that might actually be a justifiable sacrifice. I am not claiming that this is ethical, but you would at least have an [utilitarian](https://en.wikipedia.org/wiki/Utilitarianism) argument. [Answer] ## Gold? This might not be the answer you wanted but gold would still fit the properties of money, arguably much better than in the real world. The properties are: * Fungibility: its individual units must be capable of mutual substitution (i.e., interchangeability). * Durability: able to withstand repeated use. * Portability: easily carried and transported. * Cognizability: its value must be easily identified. * Stability of value: its value should not fluctuate. (<https://en.wikipedia.org/wiki/Money#Properties>) (I think I remembered a property was divisibility, that money could be given in small amounts for tiny transactions.) ## Contracts Contracts with the government or any large body. These could be for grain, hours of labour, land or anything else the government could give that is useful to many people. The closer the objects the government promise to the properties of money the better. IE grain is better than horses because horses can be very different. ## Sugar, Salt, spices or rare chemicals These used to be very expensive items which fit closely the properties of money. Exception being chemicals which could become obsolete or decay over time, hard to identify unless put in a sealed flask with a trusted signature. Spices vary in quality quite substantially in my opinion. The flaw with these is they can all be produced at will, even if with difficulty so inflation is inherent, unless the government regulated the market. [Answer] Have a few highly-skilled (non-magic) workers who can create intricate objects out of (non-magic) iron. Those objects then become the equivalent of bit-coin: you get them to record your transactions in something that can be inspected, but not duplicated or modified except by one of the few who are skilled and have the time. [Answer] Human blood. It is everywhere, it is inherently limited, and it is renewable at a predictable rate. In everyday life, people would trade paper banknotes issued by blood banks. (There is a foolproof and surprisingly effective way to make unforgeable banknotes using random numbers, which can easily be generated with low tech.) Imagine the practical and ethical implications of a blood economy. I think there is a fascinating story in that. I can think of two basic ways to take this idea: * Extracted blood is not inherently useful or desirable, except for treating blood loss. (Which would be kind of like burning money to start a fire in an emergency.) People have simply standardized on blood as a currency because of its ubiquity and its stability. This actually provides a very predictable inflation. If blood is nonperishable, then inflation happens because the population is growing and people are always producing blood. If blood is perishable (subject to exponential decay), then "inflation" happens because older blood is less valuable than newer blood. Either way, people are encouraged to spend rather than save blood. * Extracted blood is inherently useful. Hypothetical example: magic is very commonplace, and all magic is fueled by blood, the amount of blood proportional to the power of the magic. Sounds like this is the opposite of what OP wants, but it could be an interesting mechanism in its own right. I think it provides a more plausible explanation for why blood became a currency than "people standardized on it because of its ubiquity and stability" -- it began as a commodity and became a *de facto* currency. Seems like this would be subject to pretty strong deflation though. [Answer] Will Wight's Cradle has nice system for this. The coins are made up of pure mana. The more the amount / density / purity of mana, the more valuable the coin. People can use pure mana in the coin for magic but nobody can create new coins. The mana, after entering human body, mixes with the individual's magic attributes and becomes impure. New coins created by individuals are have impure mana. Each clan / school has their own way of processing mana. So, impure mana coins are of no use anyone outside of that clan / school / sect. Creation of new mana coins is done through specialized equipment that filters impury out of mana and creates new coins. But this equipment is hard / costly to make, needs continuous maintenance and even then coin creation is a slow process. This keeps the money supply under control. [Answer] Base metal coins (and/or paper bills) that have been magically enhanced (by governmental wizards) to be: a) easily distinguishable from ordinary pieces of metal and paper, and b) uncounterfeitable. [Answer] In "Red/Green/Blue Mars" by Kim Stanley Robinson, <https://en.wikipedia.org/wiki/Mars_trilogy> the martian colonists offer **services** so a form of barter. But one of the services is to increase the local oxygen level of the atmosphere by some (small) amount. This is seen as a promise to do a community service, and might be perceived as a kind of "local sales tax" paid to the planet. This would be open to abuse, in the form of All Take, No Give. So your currency comes from having a visible or measurable level of honour or truthfulness which is reflected in the flavour / colour / spin / taste of their mana / aura / magic. So I give you a week's bread, you promise to spend 2 hours gardening and cleaning up the local kid's playground because you know my kids play there. You do it, everything is good. If you don't, you "smell" bad and I can sense that, and won't trust your promise next time. [Answer] Depends on the political structure. *If, and only if* there are a strong government or authority, a highly likely scenario is that they would enforce their own currency, i.e., bank notes of some kind where a central banking institution under their control is the only one who can introduce new credit while guaranteeing the relative values between bank notes. Otherwise, Ranan's manacoin seems more likely, or simple commodity trading. [Answer] Other answers have covered most of the things we have seen used as money in history: * Gold, and things made of gold. * Items such as banknotes that promise a certain person will exchange them for gold. * Fiat currency. * Cryptocurrency (which is really just a sub type of fiat currency). To complete the set, we have two other options: Something rare that isn't gold. Maybe copper is rare in this world. Or, maybe your world is honest enough to use [Rai Stones](https://en.wikipedia.org/wiki/Rai_stones). Big pieces of rock, which are 'transferred' as an exchange of value. Except the stones are too heavy, so people just agree they have been transferred and they don't move anywhere. Kind of like bitcoin, using people's memory for the blockchain. [Answer] Not to oversimplify the issue, but my quick 2vcents would suggest that you have taken what we consider precious/uncommon and converted it into a mundane everyday consumable/tool. Why not find something we consider mundane and turn that into a sought after currency? [Answer] This answer got too big for a comment, so I'll type it out here. What you're describing is not unlike [Stormlight Archive](https://en.wikipedia.org/wiki/The_Stormlight_Archive), where various gem-like objects do double duty: they are used as currency in the same way coins are (large gem = worth more), and they are used as magical energy storage (large gem = stores more magic). There's no interference between the use as magical objects and use as coinage. Also, prison economies in our real world demonstrate that there's no conflict between items that are useful and items used for currency. Things like cigarettes, raman, and canned fish are common. If you think about what currency is, it's just a fixed position on which people can barter. > > "No, I won't unload your ship unless you pay me three > [X]." > > > "Three [X]? That guy over there will do it for one." > > > "Fine, hire him, and it will take you all night. That ship over there offered me four." > > > "Then why are you asking three?" > > > "Your stuff looks easier to carry. I'll take less for my back's sake." > > > "Ok, Ok. I'll give you two today, and double amount if you come back next week." > > > That conversation can have any of the following inserted into [X] and still feel real, because it's probably taken place at *some point* in human history. * [X] = silver coins * [X] = pounds of fish * [X] = nights at an inn * [X] = haircuts People have bartered and traded literally anything to get something from someone else. Favors, coins... you name it, it's probably been traded. I don't think the thing being traded having an actual use would in any way hinder the fact that it's being traded. [Answer] In *Earthman Come Home* by James Blish, the galactic economy used paper OC dollars backed by germanium, element # 32, for many centuries. Possibly silver, platinum, and iridium had been previous bases for galactic currencty. Germanium is a rare element that has various uses. But using it as money in *Earthman Come Home* required that its price be artificially inflated to many times its real value. Eventually the galaxy went off the Germanium standard and everyone's OC dollars became almost worthless, causing a galactic depression. the new monetary standard was antiagathic drugs - life extending drugs. Someone could choose to use his drugs - if he had any - as money or to extend his life. Anyway, this is an example of how useful items like silver, platinum, iridium, germanium, and antiagathic drugs could be used for their uses and also be money. [Answer] Dragon scales, or some other piece of a fearsome beast. This would give you interesting options on how new money is mined/minted. Is farming these beasts a possibility? Can they be hunted by a small party or only by a larger force? Can the world be destablised by hyper-inflation, deflation or a group monopolising the supply? [Answer] There are only three requirements for something to be money: * It is common enough to be traded frequently, but at the same time is either regularly consumed or isn't *too* easy to generate. * It is small enough to be traded anywhere at anytime * The value is commonly known, or at least close enough for bartering to work out without too many conflicts. I would recommend first picking one of the following categories and then your options will kind of fall into place depending on your world: * A simple mundane item * An item manufactured (possibly by magic) and regulated * A physical component to generating the "magic energy" * A source of storage for the "magic energy" [Answer] I can think of several answers to this question depending on how cohesive the political landscape is in this world. The first and simplest is that there is no currency; instead everyone barters what they have for what they need. This requires no overarching governmental structure and no widely organised economy. It also creates problems with trading widely since all transactions are made with goods that are often bulky and or hard to transport long distances. Manaconductive material *as* currency, because these materials are so very useful to this culture they have an intrinsic value based on their use rather than a simple market value based on their beauty and/or durability. This gives them a pure trade based value as a barter material already, to make them a currency you need some widely agreed standards of [fineness](https://en.wikipedia.org/wiki/Fineness) and exchange. These standards could be agreed by a wide reaching merchant [guild](https://en.wikipedia.org/wiki/Guild) without reference to any larger governmental mechanism. [Backed](https://en.wikipedia.org/wiki/Gold_standard) currency, using manaconductive reserves as the basis for a *Bullion Standard*. This requires a lot of internal organisation in the form of banking institutions and international agreements that guarantee exchanges across borders. A single large bank that spans national borders can in fact run this kind of economy without much government input. [Fiat](https://en.wikipedia.org/wiki/Fiat_money) currency would change little in this scenario but to maintain the value of a fiat currency you need institutions that are stable over long periods and can be trusted to honour their promissory notes on demand. A large banking clan or guild with a well earned reputation for keeping up their end is possibly more appropriate as the arbiter of a fiat system in a fantasy setting than the, usually, feudal governments. [Answer] I think you can still use gold or silver as currency. Either in a very "modern" or very "ancient" form. You could see it in a modern way, as in, when you use gold to create something, is basically like you're paying for the object you're making. If you use it for a spell, in a way it is like you're paying for it, it's a cost for the service you're receiving. Or, on the other hand. you could see it as a form of barter, like in the old times: where you could decide to kill and eat your cow, or use it as "money" to pay for something. I guess in your world there must still be a stable source of gold, right? Otherwise you'd run out of it anyway, whether you use it also as currency or not. ]

[Question] [ Take a country in the modern day, like the U.S., which routinely makes use of weapons such as guns, artillery, drones, tanks, et cetera. Now imagine that everyone in one of its elite squads of soldiers suddenly gains the power to shapeshift into a T Rex. While in Dino-form they retain full intelligence and ability to understand human speech, as well as being able to transform back and forth at will (let’s say the process takes 1-2 seconds). Would these new powers actually be useful in the setting of modern warfare, or a huge liability? I imagine that a T Rex would make a large target, and be less effective at killing someone than a simple gunshot. Or would the sheer intimidation factor make them a valuable asset? Would it make a difference if instead of one squad, it was the entire army? **Edit - Answering some questions:** *How big is a T. Rex?* - 12 ft tall, 40 ft long, weighs possibly up to 14 tons. *Can T. Rex's swim?* - My first guess would be no, but Micheal Chrichton's T. Rex could swim, just like a crocodile. I would guess he knew a lot more about it than me. *Where does the extra mass come from?* - They transform the same way Bruce Banner becomes the Hulk (ie. pocket universe/hand-wave?). *What happens to their clothes?* - Ripped off. If they try to transform while wrapped in steel chains or something, they would likely be seriously lacerated or strangled. *How much do they eat?* - It is viable to get hungry as a T. Rex, transform back into a human, eat, and then transform back into a T. Rex. However, they need to stay in human form long enough to digest the food and gain energy from it. *What happens to injuries when they transform?* - If an injured human shifts to a T. Rex and back, they will still be injured, though for a sake of drama let's say that injuries that would be dangerous on the human form aren't as dire to the T Rex form. This would force people to remain as T. Rex's or bleed out! [Answer] Of course it would provide an advantage. It would provide a lot of nice advantages in fact. I can tell by most of the answers that the people writing them have been as close to combat as maybe their copy of Call of Duty, so I thought I'd give a little perspective. An elite squad with unique abilities sounds a lot like an SF team to me. Special Forces means doing a lot of things that CANNOT be replaced by a drone with a hellfire missile (in other words, lots of non-kinetic stuff). While SF teams obviously do train for kinetic situations and are really good at dealing with them, their primary use is NOT to engage a major enemy force head to head. I repeat: a modern special forces team is NOT a front line infantry unit (as most of the answers here obviously assume). So what does that mean? Well, they might be jumping out of an aircraft at very high altitude, drifting over a national border with steerable parachutes, silently landing in the dark at a designated point, hiking to a target, camping out invisibly in the woods, and just *watching* the target for a week or so. They might be looking for intel on some specific bad guy, or they might need to ID what exactly somebuilding is being used for. They might then later have to "paint" that target with a laser that guides the 500 lb bomb let go by an F-15 or something else. Then, they might have to hike out to an extraction point without being seen. In such a mission, they would ideally NEVER have to engage in direct action against the enemy force. Would being able to become a T Rex be useful? Well yeah; the hike out would sure be a lot faster if you could run over 30 miles an hour! You could also carry all sorts of stuff that might be too heavy for a regular soldier, but which might include concrete proof of the state of the enemy's WMD program or whatever they are looking for. Modern SF teams always have a problem when they come across potential prisoners who they could capture but who they didn't plan to encounter. They travel light and they don't have a lot of reserve for carrying extra stuff (like 200 pounds of bad guy with good intel in his still-living head). If they do encounter someone who would be a good captive, they have to make a fast judgement and figure out if he's really worth capturing or if they should kill him or turn him loose. If one guy could turn into a T Rex, they could literally incapacitate him, clip him to a harness on the 'rex, and carry him out if they thought he was useful. Modern SF teams use ATVs and modified dune buggies in open terrain. They have used horses to get around (like when we first went into Afghanistan). Being able to turn into your own fast moving vehicle would be very useful, especially since you don't need to carry fuel. One guy could carry the rest of the team and they could cover him while he transformed back and put his gear back on. Any open area that is not a dense city would make this useful. Basically all of the "getting there" and "getting out of there" parts of the mission would be excellent times to have a T Rex on the team. TO maximize this mobility, it would probably be best to spread out your 'rex soldiers among teams of regular operators so you can have many teams able to use a 'rex for transport. Say if you have 10 of these guys, you would put together ten teams with one on each, and the other guys specialized in other things like language, pilot skills, medic, explosives, etc. So lets say you *are* in a kinetic situation. There are things that your T Rex soldier would be good for. Say you are out on an open desert. You have an enemy at extreme range and you need to slow them down while the rest of the team starts to get away. You transform your guy, set a sniper up on his head, and use the height advantage to help your sniper kill enemy soldiers from farther away than they can kill you. That's kind of an edge case, since obviously a 'rex is a big target, but having an instant firing platform can be useful sometimes. Your 'rex can also become an instant elevator to lift his team mates up onto a roof (we did a *LOT* of climbing up onto roofs when I was infantry). So, worst case scenario, your small team has to actually get into it. If you are ready for it (which I assume you are, since these are elite soldiers, not idiots), you have some battle gear for the 'rex. You might have this bundled and dropped by parachute, or the 'rex can pack it in on it's back and then leave it somewhere while in dude mode, and go back to his 'rex gear when he needs to get outfitted, or he could stay in 'rex mode for the duration of a mission depending on how long it is going to be and just wear his kit like everybody else. The point is: there would be battle gear for the 'rex just like there would be for the other guys. In today's world: we have reversed the Napoleonic paradigm, we just don't know it yet. Materials technology has actually developed armor that can stop typical infantry weapons and can be worn by a normal person. Ceramic plates will stop a 7.62 mm NATO machine gun round, which is really impressive. The only reason we haven't gone back to the old "knights in armor"/Starship Troopers paradigm is because this kind of armor is too heavy for a guy to carry *and* run *and* climb *and* also carry weapons, supplies, etc. This is where it's nice to have a T Rex around. You could have ceramic plates built into the 'rex kit that make him basically a light armored vehicle, except unlike any vehicle, he can also roll, duck behind a building, jump onto a roof (a big, heavy roof), smash his way inside a building, dig himself a trench he can take cover in, etc etc etc. It wouldn't be hard to have a couple useful weapons he could strap on his arms and use a simplified trigger mechanism with either. Heck, he could have a .50 cal machine gun integrated into a headband and hit a trigger with his tongue... You really have a lot of options with something that big. Probably best would be some kind of vehicle-mount deal too big for anyone else to carry that would give your team a real advantage in firepower. I don't know, what about a 20mm anti-material rifle? A 'rex could actually haul that around! Basically, you get the armor and firepower of a vehicle with almost the flexibility and stealth of infantry. I guarantee a smart T Rex is a LOT quieter than an MRAP when he wants to be. Like I said, he'd also be able to get down on his belly and wriggle behind a low building or a wall for cover, unlike any vehicle ever made. So your team has some emergency heavy backup in case stuff goes sideways. He would also be pretty survivable. He would have to take a couple hits from an RPG to die with the right armor kit. About some of the estimates of how easy it would be to take down a T Rex with a modern firearm: I think a lot of these people answering have never hunted for big game in their lives. Look up forums where people talk about shooting a charging bull moose or a bear. They do NOT carry rifles with the kinds of caliber used by most infantry weapons! An M-4 is basically firing high-powered, tumbling versions of slightly bigger .22 rounds. This is great for chewing up a soft target roughly six feet tall and about 200 lbs, but it SERIOUSLY falls short the second you try to take down anything bigger! You try taking your M-4 up against a bull elephant and all you are going to do before he stomps you to death is piss him off real good. You put it on full auto and other than missing with half your shots, you just piss him off more, because not he has a *lot* of "bee stings" in his hide. More rounds do NOT mean more penetration! A T Rex, with a bone structure sort of like a crocodile, would take some VERY heavy rounds to actually penetrate anything vital! I doubt a 7.62mm NATO round would do much. You would have to rock him with a .50 cal machine gun to actually stop him. Either that or hit him with an RPG or two. The problem with an RPG is you get 1 shot at a time, they aren't fantastically accurate, and they aren't designed to hit things that zig zag, roll, or dodge. They were designed to hit the side of a tank! So even if he was NOT wearing armor, (which he *would* be), the Rex would require an elephant gun to reliably bring him down. Normal infantry units do NOT carry weapons like that! Once again, think about the largest crocodile ever discovered and multiply that by about 5. Now think about hitting it with a pea shooter like an AK. It just won't work out too well for you. In summary: it would be VERY useful for a wide variety of reasons (I didn't even get into my favorite scenario: jungle warfare!) [Answer] I can imagine battlefield logistics would be much easier. One of the most dangerous and common tasks for infantry is shuttling supplies back and forth between the front lines and the forward camp. If you could load up a huge pack with crates of ammunition or even vehicles, the "runner" could transform into a T-Rex, run the munitions up to the front, and transform back, being unhindered by terrain that a Humvee might have issues with. However, in modern warfare, prolonged front line infantry fighting is becoming more and more rare, only happening in dense urban areas where a T-Rex would be a liability or when one group surprised the other. Most kills happen at pretty extreme distances nowadays. There could be a use in peacekeeping efforts, since nothing says compliance quite like a >12 foot tall dinosaur. [Answer] Stop thinking shock troops. Think strategic asset and later assassination. To start with, while your were-Rex's are still a military secret, hand them over to your espionage department and get the trained in the languages and behavior traits of your target enemy nation. Then get them behind enemy lines and integrated into your enemy's civilian populace. They don't need to get to anything sensitive yet. They just need access to public gathering places. Now, in the hours before your next major assault, have two or three of them gather in a subway central station or a big shopping mall. Have one of the team transform and start slaughtering random citizens while running quickly through the complex. Each time, the creature manages to obscure itself around a blind corner or in an empty hallway, have them transform back to human and signal a team mate in another part of the station to take the leading reptilian role. Mall security guards will quickly realize that they are outmatched and will call the police. The police will also soil their pants before calling the military. The military will have to take key defensive resources away from your targeted (valuable) strategic target, in order to go deal with the Godzilla attack. And as soon as those resources arrive at the mall, your were-Rex team will all switch back to human, escaping among the panicked crowds. Then while the enemy military is searching the mall for dinosaurs, your regular military can easily take out the undefended valuable target. This technique would only work a few times, maybe only once. But after that, your were-Rexes could split up and become one-man terrorist cells. No normal security scan could find the weapon which they themselves are. The possibilities are endless... [Answer] # No, because they cannot take their equipment with them Your average modern NATO-type infantry soldier *is* skilled at hand-to-hand combat, but that's used as the last resort. Ideally, the enemy is dead, captured, or defeated long before they reach tooth-and-claw range. NATO-type armies fight *in depth* and *synchronized*, with many services and branches fighting across a battlefield hundreds of kilometers across and deep in support of a single set of objectives. Non-ideally, the enemy can hide (often among civilian populations) to ambush and strike at short distances against fairly small friendly targets. Those friendly targets rely upon armor and upon immediate, strong artillery and air support to make up for the enemy's surprise. Infantry soldiers carry *equipment* in support of both fighting styles that T-Rex simply cannot use nor even carry in their dainty little hands: * Rifles/Carbines with an effective aimed-fire range of up to 500m * Automatic weapons with maximum ranges from 600-1000m * Indirect fire weapons ranging from 150m to 2 miles * Radios capable of calling in artillery, close air support, air strikes, naval gunfire, EOD, MEDEVAC, etc. Without the equipment, the T-Rex is simply a standalone close-in fighter, not an element of an Army...and more likely to become a casualty as a result. T-Rex isn't bulletproof or RPG-proof, is surely incapable of defeating a 40-ton Tank (or surviving a roadside bomb), and isn't fast enough to outrun artillery. Note that soldier could not change to/from a large T-Rex from inside the protection of a (cramped) armored vehicle There are a few advantages to, say, a 12-foot T-Rex that **is** capable of also firing weapons and using radios, but those are obvious. [Answer] A squad of T-Rex shapeshifting soldiers would have some advantages but depending on the exact circumstances these would almost certainly be dwarfed by the disadvantages. **Advantages** The shape shifters would have a huge surprise, shock and disorientation value initially. **Disadvantages** They would be difficult to camouflage, they would present very large targets, they would be relatively easy to kill with machine gun fire, automatic rifle fire and perhaps even large calibre pistols. They would be vulnerable to mortar and rocket fire, land mines and attack from the air. A tank would be able to kill a T. Rex by simply ramming it. Shape shifters would also become naked each time they returned to their original size or would have to undress and dress again. Such an effect could cause serious problems in extreme environments such as deserts (although it might amuse the enemy). Their size would prevent them from effectively taking cover. In open terrain they would be sitting ducks and close terrain would probably provide a more nimble enemy with better escape and avoidance options. [Answer] **Awesome for morale!** Fighting T-rexes would not be worth much against automatic weapons. But T-rexes are freaking awesome! Think of how fired up the folks at home would be to see a bunch of soldiers suddenly explode into Trexes. They could roar the National Anthem then grab blood-filled mannikins of enemy soldiers and shake them like a dog shakes a squirrel! The Trexes could come out painted in patriotic flag colors, ridden by comparably dressed models, shoot off special Trex-sized guns, and then dance to popular music. Best of all would be if the soldiers could transform partly into Trexes, so one would have a Trex head on a mans body, another a mans head on a T rex body... Or maybe that would be too freaky. OK not that. I am thinking of Captain America where they (correctly) determined the best use for a supersoldier was in public relations, to boost morale of the folks at home. I think also of the electrical zombie-exploding machines described in the (book) World War Z - pretty much expensive and worthless for fighting zombies, but a guaranteed crowd pleaser. Yes, singing, dancing, biting, roaring patriotic T rex soldiers would be awesome. I can imagine that the crowd favorite Trex soldier winds up running for office after his military career. You know he would be elected in a heartbeat. I want to vote for him now! I was surprised how many great videos of dancing Trexes there are. [Answer] **No.** One [M203](https://en.wikipedia.org/wiki/M203_grenade_launcher) Grenade Launcher, firing at 160 meters away, will quickly turn the elite troop into goo. From 800 meters away, an [M240 Machine gun](https://en.wikipedia.org/wiki/M240_machine_gun), can fire 950 large 7.62×51mm rounds a minute. The T-Rex would be swiss cheese before it could touch a claw on the modern soldier. These are standard infantry weapons. I shudder to think how a T-Rex would stand up against an [Apache](https://en.wikipedia.org/wiki/Boeing_AH-64_Apache) or an [M1 Abrams](https://en.wikipedia.org/wiki/M1_Abrams). [Answer] They would just make great targets. As ferocious as a T-Rex might seem, a single anti-tank missile would take one down very quickly, by blowing a huge hole in it. A dozen rounds from an assault rifle would at least cripple it, probably kill it. That assumes one is facing a modern military, who tend to be disciplined and trained enough to get over the shock value of seeing a T-Rex appear. The most effective soldier today is the one that makes the most effective use of modern weapons. A T-Rex would have a tough time working modern weapons systems. [Answer] T-Rex would be good in special missions. For example, counter terrorism. You have a building and the enemy is holed in it, and your T-Rex private can break doors, walls and help the other troops get in. Or, you could send a negotiator T-Rex to your terrorists holding hostages. Once it gets in, your negotiator turns into T-Rex and starts chomping on terrorists. Terrorists won't know what's going on, and they'd be too busy shooting at the dinosaur to kill the hostages first. Another great use for T-Rex soldiers is assassination missions. You get your spy close to the enemy leader, he turns into a T-Rex, bites the enemy's head off, then turns into a naked dude with PTSD. Breaking off protests is also an interesting use of T-Rexes. When the citizens in your capital protest against the government selling, yet again, your country's forests to Austrian evil billionaire, instead of police, you release the godzilla-boys into the crowd. They kill as many as they want and the protesters will know next time that it's government who owns people, not the other way around. It goes without saying that T-Rex soldiers would be great for ethnic cleansing. The international community would be ready to believe, for the correct price, that jungle beasts, fed up with the loss of habitat, took revenge on the minorities, for it is known that in every country, if things are bad, it is because of the groups who lack the numbers to defend themselves. The numerous photos and videos on facebook would document this. The National Guard will show up to deal with the threat, and will shell the area, until the houses of the offending minority would be all but destroyed, and people who did not take the hint would be killed. [Answer] Of course it would be useful, but probably not very. "All that and a bag of chips" is always better than "all that," so if you can have the option of dinosauring out for free, you should always take it. In general though, I would not expect a small population of were-asaurus rexes to make a significant difference to a modern army, in exactly the same way that I would not expect access to elephants to make a significant difference. However, if a significant fraction of your forces can turn into 25-tonne carnivores, that might change things. If nothing else, your force-protection posture would look pretty different. [Answer] Would be useless in direct modern combat, their huge size would play against them (basically, *all the disadvantages* of a modern tank without *any of the advantages*). The last wars they could've actually fought efficiently were probably some time around Napoleonic era. E. g. big organized formations, charging cavalry, bayonet attacks etc. - the T-Rexes probably already could not just win any battle by simply charging ahead (they make too good targets for muskets and cannons), but with some clever flanking or in the right situation could still wreak havoc in the enemy lines. Now they might still have some specialized and limited use. By today's estimates they were able to walk at about 20 km/h (12 mph). Not as good as a car or an APC on a road or good, flat terrain. But how about some deep raids into the enemy territory? Through bad terrain, mountains, jungles, swamps, etc. With some equipment strapped to your back and maybe a group of more conventional soldiers riding along? Need to cross that little river swarming with crocodiles? Not a problem. There are still some questions, though. How much do they eat? When it's lunch time, can a dinosaur simply transform back into the human shape, eat an ordinary human ration and transform back "for free"? Or does it have to catch a couple of buffaloes each time? What if the dinosaur catches some "T-Rex fever" - would it affect his human incarnation? Can such a soldier safely walk through malaria/plague/ebola/whatever -infested territory in its reptilian form? If a dinosaur gets, for example, shot with a small caliber handgun, or receives any other damage he can just "shrug off" - does that become a problem when he morphs back into the human shape? What if its T-Rex's tail gets blown off with an explosion? What about the momentum conservation? Let's say I am an 80 kg human, transform into a 8000 kg dinosaur, walk in some direction 20 km/h and morph back while walking - do I rocket in the same direction at 2000 km/h now? How tired do I get in both forms? Am I cold-blooded (can function at sub-zero temperature; invisible to heat-seeking tech)? [Answer] Many answers have been given. They are good answers, considering different perspectives, but I think that most objections can be solved when you observe the current context. Since we're talking about the impact of shapeshifting soldiers on a modern military, I think we can make a few other rules: > > 1. Anything less crazy/advanced than a human shapeshifting into a T Rex should logically be allowed. > 2. Anything that is based on scientific principles that the shapeshifting itself relies on should logically also be allowed. > 3. Shapeshifting into a T Rex becomes useless if the benefits of doing so can be achieved by using cheaper and simpler methods (e.g. comparing it to a tank). > > > I'll refer back to these rules as justifications for later statements. There are many things to consider here, I'll try to address all that I can think of. --- **1. Shock effect.** While the shock effect will indeed work, this will be temporary. The enemy will get used to it, they will prepare their troops, they will arm themselves appropriately (thus lowering panic from being unprepared)... There may be some residual shock from seeing a T Rex charge at you (a basic fear instinct), but any adequately trained soldier is trained in suppressing their instinctive responses to fear. --- **2. Open warfare.** I think there is little benefit to be gained here, compared to what armies already have available. Benefits * Destroying buildings (**rule 3**: you can use a tank or explosives) * Bullet sponges (arguably not a benefit, it expends super soldiers which may financially bankrupt your military) (**rule 3**: you can use a tank or something like a riot shield) Drawbacks * Massive target * Likely unable to wield any weaponry nor armor (since that would require a soldier carrying around T Rex sized armor) * Limited to melee range Due to their melee range and massive size making them an easy target, this is the equivalent of taking a knife **and no ballistic armor** to a gunfight. --- **3. Infiltration.** This may actually yield a benefit. One of the major issues with infiltration missions is that you need to pack light. This means that **if** you are spotted, you don't have much equipment to defend yourself. Infiltrations take place in places that are heavily defended, but generally are not actively in combat at the time of infiltration. This means that a tactical strike may allow a T Rex to wreak havoc and shapeshift out of sight **before** the guards have a chance to counterattack. > > **Fringe scenario** > > This is more a question for you: what happens if a soldier shapeshifts into a T Rex when he is in a small room? Do the walls collapse? Does the soldier fail the shapeshift? Does the soldier die because he can't achieve a full form (that is biologically sustainable)? > > > If the soldier breaks the walls, you could have your soldiers let themselves get captured, only to then rip the inside of the enemy compound to pieces. Even if you don't intend your soldiers to get captured, this seems like a dramatic upgrade from e.g. a cyanide pill: your soldier still dies but has also massively damaged the enemy's compound. > > > --- **4. Shapeshifting problems.** The biggest issue that the answers have raised is that you'd be naked when you shift back into human form. I don't think this is necessarily the case. I can see two arguments here that make sense. **Firstly**, the soldier could wear a custom material that can deal with the transformation. If your soldiers are capable of shifting back and forth without issue, I would expect that your scientists have been able to create a material that can sustain a similar repeated in/decrease in size. **Rule 1:** If you can already make living tissue deal with size changes, you should definitely be able to find a non-living material that can handle the same thing. \_Other fictional universes have solved this by making a special material that responds \_just like your own living cells\_\_ when a transformation starts. I.e. your body's cells cannot see a difference between themselves and your body suit's cells, thus including them in the shapeshifting process (whatever happens to your body's atoms also happens to the suit's atoms).\_ **Secondly**, your soldier may be able to "store" his (non-shifting) apparel. Your T Rex shapeshift isn't just a matter of increasing/decreasing in size (e.g. like the Incredible Hulk). Your soldier is physically altering the structure of his body. His skin and skeletal structure will vastly change. **Rule 2**: If your soldier is already capable of reconfiguring his own molecular makeup, he should be equally capable of reconfiguring his molecular makeup in order to account for his apparel. Since he's already changing his molecular structure, he could morph his body **around** the suit, thus storing it internally in the T Rex' body. There are a few ways this could be achieved: * If your soldier is capable of shifting his insides around (molecularly), he should be able to shift the apparel into a little pouch somewhere. * If your soldier is not capable of shifting his insides around (molecularly), then it's possible for the apparel to stay in place. E.g. if the human soldier is the right leg of the T Rex (and the rest of the T Rex body grows from there), then the apparel might still be inside the T Rex' right leg. --- **5. Logistics.** You have a double whammy here. The first one is relatively simple: Most armies are limited by their logistical capability. Having your soldiers transform into T Rexes is the logistical equivalent of having your soldiers transform into (fuel-free) transport trucks. It pretty much solves all logistical problems (at the cost of being less armored and more visible). **Rule 3**: when you really need armored vehicles or don't want to draw attention, simply use whatever you were using before the advent of the T Rex super soldier. **Rule 1**: Or you could simply develop an armored suit for your transport T Rexes. The second one is more insidious. Remember how I mentioned (in chapter 1) that the enemy will eventually prepare to battle with T Rexes? One answer here correctly pointed out that an M203 grenade would make short work of a T Rex. And that is correct. However, do not that you'd need at least one grenade **per** T Rex. That means that your enemy needs to have a massive amount of grenades available. They would essentially need a grenade for every potential T Rex that you bring into battle (and that's not even including missed shots, extra supplies, or lost ammunition). This will **massively** affect your enemy's army's logistical capabilities. Grenades are much larger than bullets (obviously), and need to be handled with more care. Both of these will lowers the amount of grenades that their logistical system can provide to a region. Your enemy will then be less eager to engage you in combat if they don't have an adequate supply of grenades, which is harder to come by than bullets. Secondly, this makes their warehouses more explosive (due to many more grenades), which can be a weakness if you target their ammunition stores. Logistically, this does make sense. --- **6. Playing your enemy.** I watched an episode of a Cops-like show yesterday. The cop made a valid point when he was unable to catch a fleeing thief on foot. > > Criminals come in all sizes. Slow and armed, fast and unarmed, defensive, offensive, carrying chemicals to disable officers, willing to kill, ... Police officers need to be prepared for all situations. Criminals only need to be really good at **one** of the situations to win. Cops are at a disadvantage because they have to be a jack-of-all-trades, and therefore are unlikely to outmaster a criminal in a particular field (other than sheer numbers). > > > The same tactic is true here. The fact that your soldiers **are able to** shapeshift means that your enemy needs to prepare for that eventuality. But that doesn't mean that your soldiers are required to actually shapeshift. Even if there are countless drawbacks and only one fringe case where shapeshifting grants a tactical advantage, that means your super soldiers are still capable of assessing whether or not they should actually shapeshift. It's a tool in their arsenal that they can *choose* to use. Unless these super soldiers have a weakness (in human form) that non-super soldiers do not have, there is no drawback to having the ability (other than the financial ramifications of turning them into super soldiers, of course) --- **7. Patrolling and surviving the elements.** Are your T Rexes capable of anything a T Rex is? Because that would make them useful for patrolling large regions. They could even rely on eating local wildlife rather than having to take provisions if you send them into a large jungle/forest. Given that they retain their human intelligence, that also means that a super soldiers is able to shapeshift based on what suits them best: * Cold weather? Stay in human form, you're warm-blooded. * Hungry? Become a T Rex and hunt wildlife. * Enemy soldiers trying to stay hidden? Have your squad go half human and half T Rex; the enemy will need to avoid two completely different types of enemy in order to stay undetected. --- **8. No cheesing.** Not a real chapter, but I wanted to list things that I omitted *not because they wouldn't work*, but because they are too cheesy for narrative purposes: * Utilizing the mass difference between a human and a T Rex to cheat physics. E.g. imagine balistically launching a human (low-energy) but having him land as a T Rex (high-energy). * Similarly, no power generation or other ulterior benefits from the change in size/mass. * Other than the shapeshifting itself, no superpowers that T Rexes and humans do not have. Also, humans are limited to human capabilities, T Rexes are limited to T Rex capabilities (no speaking T Rex, no human that can bash through a building) * No mysterious animalistic skill whereby a T Rex can expertly command other animals. This would also violate rule 3, there's likely a much cheaper way to coax animals (e.g. build a fake but convincing T Rex model). --- **9. Summary** In essence, there are benefits to having T Rex shapeshifters. However, they are not likely to be found in open combat, but more in the auxiliary aspects of a modern day army. [Answer] If you can do a T-Rex, why not other Theropods? Load up your were-dinos in specific roles, depending on Dino Type. The T-Rex can get to places a Tank might not, so he'd be good for Crowd Dispersal and work in public square type stuff. Something like a tank would be superior in realms like sheer destructive capability, but they are not as good at fine control. The tank could easily take out the rabble rouser on a makeshift stage, but it would also take out the stage and a bunch of collateral damage is done. The Rex could lean down, chomp, and done. Appear, munch and go away. or maybe appear and then just throw intimidation factor at the crowd. For more modern warfare type stuff, smaller, human sized Dinos would be better. Think **[Deinonychus](https://en.wikipedia.org/wiki/Deinonychus)**, which I believe the "Raptors" from Jurassic Park are based on. Not a lot bigger than a human, but much faster, much more agile. Weapons could probably be modded for them to carry and use, or even in a way that would be useful in Dino or Human mode without needing tools. They would be able to get into buildings, caves, etc. They would be fast, and they would likely be fairly quiet. I'd be willing to bet that a normal soldiers loadout could be rigged in a way that you could ditch the ruck and unzip the back of your pants to let out the tail. Transform, get the ruck back on, and go. Imagin this from an enemy standpoint. You are holed up, you see some human enemy soldiers come in to the cave, lights go out. Next thing you see is a monster with lots of teeth and huge claws ripping up your buddy. How terrifying would that be? They could also cover ground quickly where a tank or Humvee would not be able to get through, like jungle or swamp. In Short, T-Rex for big public duty, but Deinonychus for the real fight. [Answer] While the kill-the-civilians-as-a-distraction approach is a war crime I can see other uses for them in a special-forces role: 1) Team infiltrates a wooded park that's not too crowded. Member A dons some tough armor that isn't apparent, he's in the park on the outskirts of a crowd. Member B goes into the woods, transforms, runs out and grabs A who screams and releases some blood but due to the armor isn't actually hurt. After dinosaurs have "eaten" a few people don't you think the clamor for protection will be just about deafening? And there's sure to be more "victims" that simply use the dinosaur as a cover for dropping out of sight. 2) Sabotage. That oil refinery had reasonable defenses against human intruders. When they mug a worker and replace him with a T-rex, though, and he runs around breaking pipes you have a lot of damage. Lots of flammable hydrocarbons on the ground when someone pushes the button and a bunch of low-grade aerial fireworks get lobbed over the fence. (Simply tip the launchers so the average burst point is a few feet above the ground.) They couldn't get into things like the control center but they don't need to. 3) Infiltration. A pair of T-rexes can cross barriers that an unaided human could not. As with the oil refinery this means they can get past security and then do where they shouldn't be able to. (If you know nobody could have a ladder you'll consider a 6' razor-wire fence a pretty good barrier.) I'm thinking of areas that have high security surrounded by low security. 4) Infiltration over long distances. A T-rex team would have a lot longer self-supported travel distance than a human team and would be better at hunting without the use of firearms. [Answer] You should think about the characteristics of a T rex and wonder how useful they would be... In a [quick search](https://www.livescience.com/23868-tyrannosaurus-rex-facts.html), I got this: > > T. rex was one of the largest carnivorous dinosaurs to ever live, > coming in at up to 13 feet (4 meters) tall at the hips (the beast's > highest point since it did not stand erect) and 40 feet (12.3 m) long. > (...) weighed as much as 9 tons (about 8,160 kilograms). (...) had > strong thighs and a powerful tail, which counterbalanced its large > head (the skull is 5 feet, or 1.5 m, long) and allowed it to move > quickly. (...) could run 10 to 25 mph (17 to 40 km/h) (...) powerful > bite and a mouth full of serrated teeth (...) > > > I don't believe thoso skills would be enought to fight the enemies's guns [Answer] No. As others have already pointed out, perhaps the greatest thing about it would be the element of surprise. However, assuming that in your world, dinosaurs are extinct just like they are in reality, the very presence of them would be more than suspicious -- combined with the fact that they just happen to be wandering around military facilities would quickly reveal what is going on. So on the first few occasions, yes, they might prove useful depending on the circumstances, but as soon as the trick is revealed and the enemy becomes aware they do more harm than good because of their size, lack of camouflage, inability to handle tools, etc. Given the fact that in your world, people have the ability to shapeshift into something else, and what's more, into a dinosaur, I believe it would be way easier and more beneficial to turn into something else -- something that rather than calling out for attention, right the opposite, can be stealthy. For example: * Bombarding birds: very obvious, turn into birds, and drop tiny bombs onto the enemy. Before they realize what's going on, they are sweeped down. * Bacteria/poison delivery insects. These substances could be lethal in the tiniest of amounts, which could be easy to be carried by such small beings. * A small mammal, for eg., a cat: very common to see in most environments, not suspicious. Could even hide a razor in a pocket stiched under the skin and cut the throats of an entire regiment overnight without notice. * Snakes, spiders, scorpions, etc.: use what nature already provides - poison. Can be suspicious after a series of bites. * Anything that is common in the operating environment *and* preferably has the ability (properly structured hands, for example) to use tools. I do understand that these are a little off topic, but I think it is completely irrational to be able to invent a way of turning into a dinosaur but not into a common cat. Also realize that this is a double-edged weapon. Sooner or later, the enemy finds the dirty trick out and use it against you as well. It is sometimes better to secure such inventions until the very last minute they are needed -- always assume that given the fact that you've discovered it, it is possible, prepare for the worst and hope for the best. The reason is that once it is found out, you can no longer trust anyone and perhaps this would be the mindset of a rational enemy who at least generally adheres to certain moral standards of warfare. [Answer] Oh man, the only real answer is TOTALLY YES! People here are overlooking the *most* significant aspect of the scenario: > > (let’s say the process takes 1-2 seconds). > > > Without this is still viable, but this alone provide a significant advantage: **SPEED**. Let's build scenarios that were ruled out because supposelly a T.Rex was at disadvantage in modern warfare: * What about Jets, Rockets and heavy ammo? What do soldiers today, that are not T.Rex? Them **BRING HIS OWM**. But now, this soldiers ALSO ARE T.Rex. * You elite squad **is still a elite squad**. Them will *not do stupid things*. Them are smarter, but also ARE T.Rex. Them will know that a static target is death. Them will use speed as advantage. And a T.Rex is faster and more agile that some vehicles/machines. So, any advantage a elite soldier have, *plus* being a T.Rex mean a total net win. So: * **You can shapeshift in 2 seconds?** You are in front a wall. You shape, bring down the damm thing, shape again. Bum! * You are firing. Them are firing back. You shape (natural armor again small bullets), charge, kill, shape again. The constant change from/to T.Rex at 2seconds each will be hard to pinpoint not matter what. The shock of burst to be so massive? Dude... * In front of you are (tanks\artillery\machine gun nest). You outrank them (by traditional means). Your position is excellent. You shape, get on top of it, destroy, shape, repeat. * The enemy is inside building. You shape, enter, destroy, shape, repeat. * You radar detect aircraft, you get into human. Hide. Continue. * You get that aircraft is problematic. You dispatch the team to be parachuted on *top of* (military base or anything that have that stupid planes). You jump, get into base, shape, destroy. Or jump as T.Rex with a full load of bombs, as a kamikaze, but you are not idiot so, shape again, the bombs fall and you get out skydriving. The defenses are nullified. Get into, do job * You inflitrate enemy country. Get into (HQ, Senate building, Presidential House). Afraid of be detected on door. You shape, charge ahead, bring walls down, get close to VIP, kill. Shape, disappear. * You are about to be captured. Good luck with that. * You *decide* to be captured. You get inside jail or whatever. You are about to be *tortured*... good luck with that * You are in the worst possible scenario. On open terrain, against a lot of tanks, you can't outrank them. Artillery shells are raining. A simple T.Rex is done. But... You are HUMAN. A elite soldier. You bring T.Rex-Tanks (or: Armored T.Rex!) + T.Rex sized guns. to the battle. The enemy puny tanks.... And his crew are now complaining to the generals that *totally were sure* that a T.Rex is not useful on the battlefield... You T.Rex can now become an mobile castle. [Answer] I think no, or at least mostly no. Early warfare involved a lot of up-close fighting but over time people have found ways to separate them from their targets more and more. Even so, there is still some up-close fighting in certain limited settings, and this would be where T-Rexes might come in handy. For conventional fighting, their limitations would outweigh their benefits. Ultimately, in combat between T-Rex and a guy with a gun separated by a meter or two, my money's on T-Rex. Put them 500m apart, and my money's on the guy with the gun. [Answer] Have fun ending holy wars when your elite troops are literally demons. There are more drawbacks to shape shifting than the ability being good. On the bright side your elite troops will never be handicapped again. The can just shape shift from a one armed soldier to a two armed T-rex and then back to a two armed soldier. Additionally, all that mass has to come from somewhere, so shape shifting would literally destroy the environment. Your elite troops would be pretty close to demons at that point. Every time they transformed the area would be engulfed in intense flame and matter around them would seemingly disappear as it was sucked into them. Going in reverse would be even worse. Matter would just be introduced back into the environment and the temperature change would be unbearable. To be honest, I'm not exactly sure which transformation would burn and which one would freeze, but that doesn't matter. It also doesn't matter what your soldiers transform into. **The act of shape shifting would be the most effective weapon ever developed on any battle field.** Transforming into something as stupid as giant earthworms would be bone chilling to witness. [Answer] No. They's be blasted. and they'd be useless in confined spaces, because if they tried to grow to their "t-Rex form" then, depending on the strength of the structure, they'd crush themselves. [Answer] Yes, definately. Play this one straight up, and armor that dino and equip him with laser assisted tracking miniguns. 3 Guns, a small one firing incendiary tracers mounted to his helmet, and two larger ones on the shoulder that are slaved to the head mounted one. Alternate armaments can be RPG racks. He armors up in camp, moves out with infantry. His battle armor can be easily made to resist small to medium arms fire. While he can deliver substantial firepower. Think of it as rather than having a soft squishy tank, you have a heavily armed/armored 20 foot soldier, with the ability switch back into a normal infantry troop for retreat, or when the big targets become no longer desirable in the current theater. His battle armor could pack his standard infantry kit, it would just change into it when done with his dino duties. [Answer] Yes, with proper weaponry. They would not be carrying AK47's. They would be carrying cannons. Edit: How the T-Rex would be carrying weapons is a mechanical detail (some sort of "carry on the back"? Put them down when shooting to avoid recoil?). The important point is that suddenly you have a battery of fairly-large cannons in an all-terrain vehicle. [Answer] T-Rex might be big and strong, but a M-16 bullet will rip into them just as easily as human flesh. It wouldn't be like the movies where the giant gorilla reacts to bullets like wasp stings. **Advantages** 1. Speed (pursuit) 2. Surprise attack after the human form was disarmed and captured 3. Strength, to move or crush obstacles 4. Teeth **Disadvantages** 1. Limited use of equipment (although a vision of a t-rex with a bazooka is awesome!!) 2. Transformation would have less armor and protection than human form in full combat gear 3. Obvious targets (effectively automatic taunt) Personally, it might be more flexible and have a greater story if each individual is able to transform into different animals. A scout might have an animal form that is quick and silent. A sniper might be able to transform ONLY his eye into an eagle's eye (and his entire body to travel quickly to new perch). Some may have roles to quickly move other team mmebrs and equipment in various terrains: water, land, etc. And then of course you have that one stupid hot-head (and life of the party) who transforms into that t-rex. [Answer] Honestly, I would rather have trained mosquitoes with diseases. They could fly in a week before and make the whole armed forces sick, and they are hard to stop. Bullets can't kill them. T-Rexs would not even make it in WWII against a tank brigade. [Answer] Well surely it would work if you're fighting against inferior soldiers with little military power, but if you're up against China or Russia, then forget about it! ]

[Question] [ Recently, I asked [what could kill all humans except for those in low orbit](https://worldbuilding.stackexchange.com/questions/2625/could-a-disaster-kill-all-human-life-on-earth-but-leave-astronauts-in-low-orbi). Out of the answers that popped up ([which included the Ragnarök](https://worldbuilding.stackexchange.com/questions/2625/could-a-disaster-kill-all-human-life-on-earth-but-leave-astronauts-in-low-orbi/2626#2626)), I picked a plague as being the most desirable for my particular needs. **Some background** A virus, purposely engineered to target and kill humans was (deliberately or accidentally) released and successfully killed all human beings within the span of a few months. Well, not quite all humans, the [6 people in space](http://www.howmanypeopleareinspacerightnow.com/) were not infected. When it was clear that this virus might very well kill all humans, they were instructed to stay in space for as long as they can last and then attempt reentry and hopefully restart society. The people in space are 3 women and 3 men, they are all relatively young, able-bodied and intelligent, as well as educated. **The question** Assuming these men and women return 8 months after the virus got released and thus spent between 8 and 14 months in space, what could these people do in order to maximize humanity's chances of survival? (and what are some less obvious problems they will face?) You may assume that apart from humans, other life on the planet has not been directly affected and that people on Earth could have made some minor preparation in order to help the 6 remaining humans with their task. Also keep in mind that they cannot know for sure if there might be survivors. (There are none, but our astronauts don't know for sure.) [Answer] The existing answer covers the idea of egg and sperm banks, if you've got access to these then great. For the sake of variety I'm going to assume there are no other sources of new DNA available and try to focus on the bigger picture rather than the unavoidable genetic issues. ## Survival First and foremost everyone MUST survive, inbreeding is going to be a massive problem for future generations however if people die then there will be no chance for humanity to reach future generations! The survivors must ensure they are safe, they must (if possible back up their own DNA through egg/sperm banks) but they must also ensure their own health. Whatever wiped out the rest of humanity must be handled, medical supplies, knowledge, sterile surgery must all be preserved. ## Repopulation As I mentioned above if there are sources of other human DNA around that's by far the best option, in vitro fertilisation from dead donors would an ideal solution because it rebuilds the population from a wider variety of "parents". However assuming that this isn't an option it's likely that sexual partners will be designated by some authority in order to maximise the genetic variations produced. I'm not going to speculate on the details of which pairings will produce the best results as it would depend largely on the six people in question. Second (and I imagine this is going to be very obvious), each of the women must spend as much of the rest of their lives as possible pregnant with as many permutations of genetics as possible. It's not going to be much fun for the women involved (being permanently pregnant) but the more children the six people can have (each man with each women) the better. However this needs to refer back to my previous point, if a 1st generation woman dies in childbirth this is worse than not having the child at all. With her the survivors lose her knowledge! Family trees must be mapped in excruciating detail, it's impossible that inbreeding is going to be avoidable but at least everything can be documented for future generations. I expect that sex will lose its taboo status very quickly... after all everyone is doing it with lots of different people! After the first few generations the issues of inbreeding are likely to become an issue, the six people in question will have a very limited amount of DNA to work with (although on the bright side a massive proportion of genetic defects will be eliminated overnight!). The colony will be faced with some serious issues such as whether people who are born with genetic defects should be permitted to breed (and I do suspect it will be a permission/licence based society) or whether their "faulty" DNA would be removed from the gene pool. After a few generations I expect DNA profiling will have become a major part of every day life, people with "good DNA" will be highly sought after as parents. The family structure as we know it will have been all but forgotten and children will be raised by the state. In short I don't believe it looks good for our colony until the population develops gene manipulation technology, however in the early days their first priority will be survival of the human race rather than genetic anomalies which will appear in a few decades/centuries time. ## Knowledge, Learning and Jobs Everything must be written down and backed up! The original astronauts are going to die and they must have everything they know backed up as soon as possible! People are going to have to put real value in education and training. The onus will be on learning skills yourself. Hopefully records of humanity have survived - people will need to re-learn everything from maths, to science, through cookery, sport, healthcare... everything. The original survivors are going to be highly educated but likely in a niche field. It's very unlikely they're going to be able to be able to quote much Shakespeare for example! ## Labour With women being pretty much permanently pregnant and their unborn children too valuable to the men are going to have to take on a lot of responsibility for the physical labour. Feeding and powering the colony, scouting and exploring the post apocalyptic world. I suspect it's likely that women are going to take on much more of a planning/learning/teaching roles (which they can do while pregnant) and the men will be the hard labouring. ## in summary * Lots of babies * Inbreeding is going to happen, there's nothing they can do about it. However it's not going to be an issue for a generation or two. * Planned breeding and breakdown of traditional families * Women will take on academic roles * Men will largely take on physical roles [Answer] Everybody mentions sex and inbreeding, but first these astronauts have to land without assistance, and recover from months in zero-g. Bone loss and muscle atrophy, as well as the impact on your sense of balance, require months of rehabilitation, and without medical personnel to help them, that's going to be tough. What also matters is where and how they land. I believe the Space Shuttle generally lands on the runway where it's supposed to, but other capsules tend to land in the middle of nowhere, sometimes in the ocean. With nobody to pick them up, humanity's future could be very short indeed. If they do manage to make it to the rehabilitation center, I hope it comes fully stocked with food and other supplies for a couple of months, because it'll be a while before the astronauts will be able to hunt or scavenge their own food. If the earthbound people who died made some effort to help the astronauts to survive, they hopefully put the rehabilitation center close to the landing strip (or vice versa), and filled it with all the supplies, tools, equipment and information they could. This center will be the start of the new civilization. It might even include equipment to screen for genetic defects caused by inbreeding. Our astronauts are probably intelligent and educated; inbreeding is probably not going to be their biggest problem. The dead earthbounds may even have transferred the contents of a sperm bank here. [Answer] Unfortunately, despite human intelligence, despite sperm banks, and despite all the environmental factors being kind to the last remaining 6 - there is no way the population could survive. Our best estimates for how many genetically different individuals you need to keep a population going with 95% confidence for 1000 years is around 4169 individuals: <http://www.sciencedirect.com/science/article/pii/S0006320707002534> If at any time the population dips below that number, the population is considered extinct without human intervention, as the genetic diversity in the population is so prone to genetic drift that all alleles will become fixed or dropped given enough time - irrespective of planned mating arrangements - and recessive mutations kill everyone off. This is called the Minimum Viable Population (an important statistic when dealing with endangered animals): <http://en.wikipedia.org/wiki/Minimum_viable_population> So you've got 3 women. Forget the men, if they can't *make* babies they are junk, because frozen sperm lasts forever. With the current technology, the only thing that can make a human baby is a human female womb. There are no ex-vivo births. There are no animal surrogates. The technology isn't there, and it's impossible for 6 astronauts working their entire lives to change that. The most births (not children, births) a human has ever had in their lifetime is 27. Frozen eggs for IVF last at most 10 years, so the astronauts would never be able to hit 27, only 15, with a baby every 8 months. Which means the astronauts, could create AT MOST 45 totally unique individuals to get the ball rolling. Those F1 children, assuming they are all girls because male sperm was selected out, would have to use frozen sperm to make their life-time goal of 27 children a reality. Remember, we don't need 4169 individuals, but 4169 UNIQUE individuals, or rather, 8338 unique chromosomes. So, those 45 use frozen sperm to make 27 half-unique kids: 45 \* 27 = 1269 individuals, but only 1314 unique chromosomes! So picture this.... we are 60 years down the line now, with 1314 people who have about as much genetic diversity as 657 people. Everyone is female. The original 6 survivors are dead. No one remembers why, but they know they have to spend their lives cranking out frozen-sperm babies, because their grandparents said so. They spend their lives crawling around the wreckage (pregnant) looking for signs of frozen sperm, whilst trying to control their 27 kids - 11 of which are also pregnant. They know their needs to be at least 7024 births before the last drop of sperm thaws out and they only have each other for company. It's a pretty bleak future :P [Answer] With a founder population of three pairs, you can't avoid first cousin pairings. But with four pairs, all of which produce at least one fertile male and female, they can ensure that all descendants will be no closer than second cousins by breeding as shown in this schematic: ``` M F F M F M M F # Morse-Thue sequence of sexes a b c d e f g h # older generation `-+-(---(---(---' | | | | `---(-+-(-------' | | | `-(-(-----+-----' | | | `----(-------+-' ,-+-. ,-+-. ,-+-. ,-+-. a' b' c' d' e' f' g' h' # younger generation ``` This could be implemented in a population as something analogous to the "skin group" system of Australian Aboriginal kinship. * A male of skin group `ab` and a female of skin group `ef` are an `ae` pairing, which produces children in `ab`. * A female of skin group `ab` and a male of skin group `ef` are a `bf` pairing, which produces children in `cd`. * A male of skin group `cd` and a female of skin group `gh` are a `cg` pairing, which produces children in `ef`. * A female of skin group `cd` and a male of skin group `gh` are a `dh` pairing, which produces children in `gh`. * Other pairings are forbidden as incest until the population rebounds enough. ["Inbreeding" on Pin Eight](http://pineight.com/mw/?title=Inbreeding&oldid=11879#Breeding_patterns) shows a diagram of this pattern continuing through three generations, with a proof that all great-grandchildren are second cousins (and no closer). And with breeding taken care of, they'd also need some counterpart to the [Survivor Library](http://www.survivorlibrary.com/), a project to collect all information needed to restart civilization. [Answer] This is one of the most fascinating questions I have seen in some time on this site because there are so many dimensions to the question. (I am being rather America-centric here but considering the needs of your astronauts - a highly developed space agency, civic infrastructure such as roads, instruction manuals that every astronaut regardless of their origin can read, ease of access to a wealth of resources, safety in terms of wild animals, clean air and water - The USA and to a lesser extent Canada would be a very good choice. Russia would be excellent as well though, and I think most everything I mention here would still apply.) **Specialization** NASA astronauts, and I assume current spacefarers from the rest of the world, are chosen for a given mission based upon the experiments and repairs that we intend to execute during that mission. So, you need to consider what these six are good at. You must have at least one pilot and one engineer, probably more of each. Chances are you have a biologist/geneticist who may be an MD. This would be very good for your scenario. You probably have a chemist. Pretty much everyone will be a decent level computer programmer. You may also have a botanist if you are lucky. A lot of prolonged space-based experiments involve growing various plants in zero-G. Whatever you have, they are six individuals of high intelligence in extremely good condition and with very advanced, but fairly specialized knowledge. The practical end result of this is that there will be significant gaps in their knowledge. Let's discuss later where they will be important. **Reproduction** This has been covered well. An immediate birthing program would need to be put in place, but I think chances are, the astro-men would have a rather limited role here. Their sperm would remain viable for many years to come, whereas they may be in a hurry to find viable donors of the greatest genetic diversity possible, both male and female. I don't see a whole lot of issue here worth noting. The biggest source of conflict is likely to be that we have a viable Mongolian woman's egg, and just the right South African father's sperm, but the blood types don't match any of the mothers so you have to trek to find the correct anti-rejection drugs. Also, the first several generations of girls will need to start getting pregnant at or near the age of 13. Pregnancy and sex may become vastly separated concepts. **Disease** Here's the good news. The plague killed off almost all sources of infectious disease your hero's are going to run across. Both viruses and bacteria tend to be highly specialized and those that will harm humans tend to live only in humans. I say 'tend' on purpose. There are still many that will cross species boundaries, and mammals are going to be your biggest danger with birds close behind. Parasites can be a problem, with malaria being a bigger issue than the common cold to your heroes. Forget the flu and pneumonia, lyme disease and rabies is your killer. **Education** This one is tricky. What good will a sociology or pharmaceutical (linguistics?) degree be to generation 0-10 humans? The knowledge would be preserved through books and video lectures, etc., but at what point would you decide that this is knowledge worth having? At such a point, who would be around to teach, or can people have enough general knowledge that they can self-teach? Would such pursuits be planned out by Gen-0 so that Gen-10 has a job assigned to them at birth/first-appearance-of-aptitude? Are they simply lost and rediscovered 1000 years hence? Some things may seem unimportant at first, and in fact will rely upon skills our astronauts do not have, such as farming. There will be tons of food laying around, and a lot of it would survive for decades, though your choices get fewer and less interesting as time goes on. And six non-experts working full time do not have the ability to raise the biodiversity necessary to make a good lasagna from seed. They would still have to. There are seed banks out there, but they need working refrigeration to last more than a few years. **More on Food** Since mammals and birds will be the biggest bio-threat to your heroes, fish would be the best initial source of sustainable protein. It would be a good idea to husband/domesticate a few reptile species as well, though choosing them would have to be done carefully. Iguanas come to mind, and constrictor type snakes that don't get too big would be good. Even boas and pythons that are slaughtered before they get to be around one meter long would be ideal as long as they procreate before that. Wild versions of big-agro plants would be abundant for generations, though the American food-belt would face drought conditions for generations without anyone to maintain irrigation systems. **Security** Let's face it. All animals are wild animals now. At the point where people realize there is no bunkering down and surviving this, they will let their pets loose. After an entire year, they are pretty much feral. But after only a year, some will return to domestication with little effort. Dogs and cats may become as important as they were to the cavemen. I ascribe all malicious intent to humans, and we can consider that gone at this point. A solid, well-maintained chain-link fence three meters above ground and one meter below completely surrounding your new home should be fine. The materials are readily available and it wouldn't take more than a week or two to secure a sizable area for several generations. **Keeping the power up** That oil/gas/petroleum we were worried wouldn't last more than a few decades? We now have enough for several hundred years. The electrical grid will be hugely unreliable though. A storm could take down a few lines, and if the option is between finding the central office, turning off the proper switches, getting a cherry-picker to the right location, repairing the line yourself and switching the power back on with all fingers crossed, or simply moving to an unaffected area, your heroes are probably moving (Or just living without a power grid). I think localized power sources will dominate. Wind and solar. After a few generations are out the shoot, I wouldn't be surprised to see someone develop a hydro-dynamo in the small-scale. Gas would probably only be used to power cars and for heating and cooking. Viable seed and reproductive cells would have to be moved to where the heroes could guarantee continuance of power. Maintaining this system would be a constant concern, if not a full time job. I think the interesting part would come in 20 generations into it when two-thirds of the population are forced to found new population centers, or 30 generations down the line when the all-knowing computer program which the progenitors set up says it is time for governance and law enforcement. Or 50 generations in when someone approaches the machine to receive their job and 'Archeologist' comes up, and no one knows what it is. [Answer] One of the biggest problems reestablishing humanity with a group that small is a lack of genetic diversity. People make jokes about inbreeding because it can be a serious problem, leading to birth defects and genetic diseases. Read up on [haemophilia among European Royalty](http://en.wikipedia.org/wiki/Haemophilia#European_royalty). So if it is possible for society to store *disease free* genetic material (sperm and eggs) or at least use existing (hopefully clean) stores of such material, then that would be a huge help. It would probably be helpful if those stores could be moved to one central location where the would be easier to maintain and access. Eventually, this material would make it possible to reestablish a fair range of human genetic diversity. If the machinery can be kept working, the genetic material could be gradually as the population base expands. On the other hand, if everyone is infected and it is not possible to get or save any disease free material, the survivors are going to have to do the best they can and accept that there may be some problems. The best thing they can do is for each of the three women to have at least one child with each of the three men. The more, the better. Their children should be encouraged to mate only with those who don't share a parent, and in general they should have as many children as possible by as many different people as possible. This will likely result in a society with very different moral and ethical standards from our current society. [Answer] Newbie here, just stumbled in and am already hooked. Reading and re-reading the question, I think I understand how I'm supposed to address it . . . . but I can't. Partly due to the impressive knowledge of genetics shown already, partly because I think something needs to be addressed before that. A couple or three modest (ahem) questions: What if they don't care about propagating the race? What if even one of the women says, "No way am I going to be impregnated even *once*, Buster." What if one or more is/are gay? Showing both my lack of knowledge and my Bleeding-Heart-Liberal leanings: I assume (America-centric, as mentioned above), astronauts are military people, right? Assuming that, and projecting some bias, some firsthand knowledge and a lot of "data" from movies and tee-vee, I see people who have achieved this level of rank/competence/something as being very conservative. In a non-political sense. People who would be uncomfortable having sex with different partners who are having sex with different partners whom you each know intimately. I can probably project this one onto the women safely, but definitely the men: competitiveness. That's one of the character traits that pushed them to this level of accomplishment. Three of them perhaps not too big on co-operation in societal-sexual matters? Religion. Might my conservative-projected astronauts be devout Southern Baptists? Catholics? Mormons? Different attitudes about birth, women and morals. I'm given to understand that astronaut-candidates are tested for psychological stability. Might or might not that have something to do with their attitudes? What if the scenario is so far out of their mental confines--military blinders--one or more explodes mentally and turns into a raging hatchet-murderer? Okay, I could go on, but I realize I've drifted 'way, 'way off course, but the human/personality angle is what hit me first in this situation. The genetics bit was a quick education for me, though. Thanks. [Answer] There are three main challenges: Short-term survival; reproduction; and rebuilding society, agriculture and industry in the long term. The last of these is likely to be the most difficult. # Short-term survival The astronauts would have to find food and shelter while they recovered from months in zero gravity. This might not be too bad, assuming they could land near (or travel to) a formerly populated area. Suppose New York City has enough stored food (in canned/dried forms which can last a long time) to feed 10 million people for a day; then it can feed 6 people for 4500 years! Similarly, there would be plenty of fuel, medicine, and spare parts for the first few years. # Reproduction If the Earth-dwellers set up a suitable bank of sperm/embryos before the end, this would help a lot with genetic diversity. It could still be a problem if one of the surviving mothers has a nasty recessive gene; for a historical example, see the spread of hemophilia among Queen Victoria's descendants. Frozen sperm are viable for about [50 years](http://www.thespermbankofca.org/content/how-long-can-sperm-be-frozen), so they have that long to maximize genetic diversity of the survivors. If possible, they should select sperm so that the first two generations born are (almost) all female. If each of the 3 original women (who are likely to be over 30 years of age) has 5 daughters, and each of them has 10 daughters, the second generation is a group of 150 women who *all* have different fathers (plus a few males, for when/if the sperm bank fails). This should provide a reasonable amount of genetic diversity. After the "legacy" sperm is no longer viable, the survivors will start reproducing naturally. Having lots of children would still be a good idea, to ensure that disease or natural disaster doesn't reduce the population below a viable level. # Long-term rebuilding Things get particularly interesting about 50 years after the disaster. The last of the original survivors are dying. The population numbers somewhere around 1000. The good news is, they have books from the past to instruct them in agriculture, medicine, engineering, and other useful knowledge. They still have a lot of old resources to scavenge, although some have been lost as buildings collapse from neglect, and materials are damaged by weather, animals or vegetation, or simply rust away. The bad news is, they do not have anything like the numbers to maintain the crumbling technology around them. As I argue in [this answer](https://worldbuilding.stackexchange.com/a/3296/2556), that needs at least 10 million people, which they won't have for several more generations. In particular, modern medicine will be gone. They will at least know about basic hygiene, but stockpiles of drugs and vaccines will have long since expired and they will not have the manufacturing base to replace them. They will also be short of expertise. You can't learn to be a farmer from a textbook; it requires practical experience which is passed down in person. They will have to rediscover agriculture by trial and error, before the last of the stored food runs out or becomes inedible. They would at least be able to use surviving populations of domesticated food species. (Things like beans, potatoes, and a few pigs and chickens would be useful; this is a case where the doomed Earth-dwellers could help out before the end.) As long as the population remains small, hunting and gathering wild food would be an important part of their diet. A colony of a few hundred survivors, none of whom remember the Time Before The Plague, will be living a low-technology existence in the ruins of a high-technology world. From this point, it's hard to predict how society would develop -- although a quasi-religion might well develop around the writings of the original survivors. Some well-intentioned laws and commandments laid down by the Founders might be interpreted in very strange ways a century or two later. [Answer] I would imagine that the biggest problem with such a small number of survivors trying to rekindle the light of civilisation is going to be inbreeding. If society saw this disaster coming and were able to prepare, as you suggested, then the sperm and egg banks of the world could be used (provided they don't defrost too quickly whilst nobody is tending to the power supplies) to widen the gene pool. The biggest hurdle in this case is likely to be viable hosts for carrying test-tube-babies to term. With sufficient advance warning and ignoring the obvious moral objections, it should theoretically possible for a non-human to act as a surrogate mother for a human embryo. The other option is that the female astronauts become serial mothers, acting as a surrogate mother for as many babies as possible during the remainder of the lives. [Answer] One more aspect not yet discussed is that for such a small gene pool to survive long term, they will have to separate. Assuming they have communications technology, they can still meet virtually, but there should be no possibility that a simple cold or localized natural disaster will reduce or eliminate the fledgling population. This will cause problems trying to spread the remaining limited genetic material, but the even if the risk is low, the consequences are too great. Almost immediately upon learning that they are the most likely last hope, they should probably attempt reproduction in space, or immediately upon landing, and separate. Perhaps each pair would leave with the female of a given pair pregnant from a male that she's not staying with, so at least the first two births have different genetics. Once the next generation reaches puberty, they can be traded to ensure widespread distribution of genetic material. Simple quarantine measures could be enacted to avoid spread of minor illnesses from one encampment to another. This will ultimately lead, though, to power imbalances and conflict. But that is the nature and history of humanity, so while there will be desires to stamp that out, a generation or four down the line will likely have problems. This, though, will actually serve to preserve humanity from a genetic standpoint, as long as it occurs generations down the line and not immediately. By ceasing trade of any kind one protects from diseases. By stealing children and integrating them with your community you can bolster your genetic pool. In either case, from the standpoint of restarting humanity, having a group or two that distance themselves from everyone else will ultimately increase human survival. Different environments, difference diseases, different diets, different mutations and so forth will cause different selective pressures. As long as they can get past that first bottleneck necessarily caused by the small pool of DNA available, separation will improve survival. [Answer] > > The thundering machines sputtered and stopped. Their leaders talked and talked and talked but nothing could stem the avalanche. Their world crumbled; the cities exploded. A whirlwind of looting a firestorm of fear. Men began to feed on men. -[The Road Warrior](http://www.script-o-rama.com/movie_scripts/m/mad-max-road-warrior-script.html) > > > What things were done by the plague faced population? I would assume it was every man for himself. Not many people would be concerned with setting aside commodities for the (*completely* forgotten about) lucky **VI** who will probably just burn-up on reentry or drown anyway. --- The **VI** would (and should) have absolutely no concern with maximizing humanity's chances of survival, only their own, which of course leads to the former. They need: water, food and shelter. In that order, provided they aren't going to freeze to death in the meantime, or be *eaten* (A serious consideration that the Russians took into account, sending their astronauts up with pistol/shotgun/rifle combination guns for if they had landed in the wilderness). Re-population comes naturally (more so than most of us would like), especially when the drug store is closed. The first few days, months, a year; will be the *hungry*, hard part. (The Twinkies truck has already been ravaged, I assure you.) **Without human intervention, the Earth would be *more* of a mess.** Maybe I missed it, but the TV show *Life After Humans* seems to gloss over the initial period of neglect. Lots of stuff will start to 'go wrong' when people stop showing up for work. Factories such as oil production facilities are likely to have caught fire by now (like [Morton-Thiokol's Woodbine](http://en.wikipedia.org/wiki/Thiokol-Woodbine_Explosion) plant explosion). Caustic chemicals left in 'temporary' containers are beginning to leak. Failed blow-out preventers? Yuck. Really my question would be: What hasn't burnt down yet? For a limited time all the utilities would still work; gas, electric, water... which means when a tree falls on a power line, it eventually sets the entire city on fire. Most large cities would have burnt themselves to the ground, left unchecked. Cockroaches and rats have begun to take over the world, again; setting the stage for another Dark Age style plague. **The VI would soon become sick and die** from the inevitable next plague or some unforeseen, unseen chemical catastrophe (like the [Bhopal disaster](http://en.wikipedia.org/wiki/Bhopal_disaster)). --- If they're aboard the ISS, and must escape using the [Soyuz](http://www.nasa.gov/mission_pages/station/structure/elements/soyuz/landing.html#.VE7_ZWfg00o), three of them are out of luck anyway. Also, welcome to Kazakhstan, where it's currently sunny and 7 degrees Fahrenheit. > > Up to three crew members can return to Earth from the International Space Station aboard a Soyuz TMA spacecraft. The vehicle lands on the flat steppe of Kazakhstan in central Asia. The return to Earth takes less than 3.5 hours. > > > --- Lets assume humanity made it; fast-forward a thousand years. Still we would be cleaning up the mess left behind by own defunct and now ancient civilization. The phrase "to big to (let it) fail" comes to mind. [Answer] > > What if they don't care about propagating the race? > > > What if even one of the women says, "No way am I going to be impregnated even once, Buster." > > > What if one or more is/are gay? > > > Given the original premise of all 6 being the occupants of the space station, we would be dealing with 6 highly intelligent, logical people. Even a space-closet drag queen would understand the situation and do what is needed. Highly unlikely any have excessively strong beliefs - a catastrophe of this magnitude would probably wipe out any concepts of a benevolent deity, even if Pope Francis was visiting. Two things that don't seem to appear elsewhere: * a quick check of the current (and recent past) female astronaut corps shows that they are all rather old - the one up there now is 38, recent ones have been in their 40s. Perhaps the agencies deliberately select women past their childbearing years? Or you need to be that old to have enough experience. So you're not going to get more than one, maybe 2 children from each female. Puts a severe crimp in the math. The woman who had 27 children probably had some twins and started in her teens. * lets assume we get a couple of early-20's girls in the mix. You can increase the genetic diversity further by breeding across generations. First-gen female A could probably remain fertile long enough for the son of B+D to reach reproductive age, original males should have no problems with second-generation females - 15 is safe enough which puts even a senior astronaut at under 60. This is the apocalypse, people - we toss ALL of society's concepts out. Need to keep careful records of who is related to whom though, and teach the descendants what to do with them. [Answer] Since several excellent answers address the basics, I will try to fill in the gaps with less obvious problems that OP is also asking about. * some or all of the original six may not be interested in repopulating earth. They may suffer from depression, PTSD, dissociative amnesia, as a result of the demise of the world as they knew it. The idea of being an incubator or giving birth to girls doomed to be incubators from age 15 onwards may seem unethical to some or all three of the women. * the future generations may refuse to cooperate. There is no guarantee that every (any?) girl in the second generation will agree with the ultimate sacrifice of turning themselves into incubators. With bottled water and imperishable food a plenty, "rebel" youth may not sign up for the repopulation project. * a tyrant may arise early on. If they take the advice given here, there will be few men around in generations 2 and 3. What if one of them is physically imposing psychopath who decides all the incubator women should serve him instead? [Answer] Even supposing they have sperm and eggs banks, will they know how to perform IVF? As other mentioned their knowledge is limited to aerospace science. They'll have to train someone to do that. [Answer] The question of inbreeding could be addressed by using programs used by zoos for breeding of captive endangered animals. Those track and optimize pairings to maximize genetic variability when specimens are rare. That could be kind of a kooky reference for the story. [Answer] Black sheep here but I think a good path for this scenario is to emphasize all the reasons why every conceivable attempt at this scenario is futile and in the end, which is not far away, all humans are dead. Maybe they do believe their goal is to repopulate. Say they have a couple volunteer and quickly into this effort they realize just the basics of restoring a small colony requires more skills than they were prepared for. Nutrients, natural threats, etc. It's not like they're all forced to camp in the Amazon or anything, but a dead to the world remnant of society might prove to be more inhospitable than one may think. For one, with everyone dead what happens to the nuclear reactors left running? Fukushima is on the edge of meltdown right now. If everyone died, what does happen there? How much of the land is off limits from that one alone? Then the rest? What about miscarriages? Medical emergencies? Basic medicine used for childbirth which could prevent anyone else from volunteering to be the next host. I mean... your crotch is going to be ripped up. Tearing is common. Shall we just guess on how to sew that thing back up? While I am listing some negative things to dissuade the intention of the question, these pessimistic details might be what makes the story interesting to address. And ultimately the story of survival ends up being a story on failing to survive. My personal opinion - Humanity wouldn't get even one more generation out of this. If children are born, it will take a village to raise them. This village is all but burnt down from the beginning. One flu could kill everyone. One person who can't handle the depression and isolation. Maybe people disagreed with them once and planted the seeds of rebellion, tyranny, or the belief that it is their responsibility to do "god's work" which is always insane and full of stupidity. A million things could go wrong, and whoever is left to inherit the earth will have to contend with the onslaught of mental and physical challenges most people fail to endure for a few weeks. ... someone here mentioned mormons though. Keep in mind they have enormous stockpiles of armageddon survival in unknown locations. If a plague hit, for sure some of the higher ups who know where they are may have migrated there. They are preppers, and they are not alone. It might be hard to conceivably eradicate all of human kind without some of these preppers being isolated, filtered, and much better off than the crew of this vessel. If you are adamant about all of humans except the 6 being dead, consider the mormon stockpiles probably still exist. If you get to one of those, and you can figure out how to get in, your odds are greatly improved. ]

[Question] [ In my story, I have this character that cannot die and cannot grow old. She got this from a curse. When ordinary people see her, she probably looks like 20 or so. **How can I make it so that nobody knows she is immortal?** I know she can just hide in a cave or something for hundred years and then suddenly appear, but I don't want that. I want her to keep appearing in the story. Maybe she could change her appearance, but her voice, personality, the way she does things, etc, she can't change all that every time. Also, if she had some friends, would they notice that she never grows old? If so, how long would it likely take for her friends to notice that? **Update: Let me explain the world** It's a modern era, like there's a lot of building everywhere but there's no cars, no fast transportation, no internet. Something like that. Electricity still exists though. The society is pretty much just like our society now. Magic is, well, source of magic is everywhere but not everyone can use it. Because using magic is kind of risky. You first have to set a contract with magical monster in another dimension, and then you have to defeat him in a fight. Many people die in this process.  [Answer] **Looking older is not that difficult.** It's especially easy if you are a woman. I know women in their 40s who look like they are in their 20s--consider that 40 year olds strive to look young. How to look 40: * stop wearing what 20 year-olds wear, even if you have the body for it. Wear more conservative outfits. * change your hair * wear more makeup as you "age" You can say things like "I could go out of the house with nothing on my face when I was 20, now, not so much" * wear glasses (because your vision just isn't as good now that you're older) * gain weight, then go on a crash diet when you're your own daughter--or sister or cousin or whatever when you come back as your younger self. **Step two, change circles.** Keep a few of your older friends, but continue to make friends with 20 year olds. If age comes up, you're just one of those annoying people who looks youthful. Complain about how you still get carded for everything. Trust me when I say that you have about 20 years before anyone notices in a way that's negative, or that makes them believe you are immortal--unless this is common enough that people think of it. Seriously, people look at things as to what they are given in life, and rarely look outside that. **Step three, as others have suggested, mention your "daughter"**, whose identity you're going to establish for the next 20 years, with pictures you fake, achievements you talk about and the like...it's not too hard to apply for a social security number--you had a home birth, so there's no hospital records. Maybe fake a pregnancy before the "birth." Then, as the daughter, enroll in college, completely changing your look, maybe back to what you looked like in your 20s. In the meantime make sure post cards come in from "old you" from France or something. While new you is in college, "old" you can die in an accident. It will take something to arrange for all this. New you can be devastated and talk to old you's friends, with whom you share memories of your dearly departed mother, and it gives you an excuse to visit them. Those old friends will be in their 50s and 60s, but new you will also be making new friends in their 20s, and you'll be learning about the new young culture, and you can start the process all over again. Those old friends might also give you a career start with recommendation letters, as well. You'll want to fake some hospital records of childhood illnesses and arm breaks, for sure--attend to every detail--think of a typical person and what kind of record trail they leave in their lives and make sure that you have that. Homeschooling/home tutoring is fantastic, BTW, because if anyone gets suspicious they can't ask your teachers. **There's also the possibility of starting to live as your new self in high school instead of college.** It goes a longer way towards establishing your identity and makes it easier to get into college with real transcripts. 20 year olds can definitely pass as high schoolers--I'd suggest boarding school to get around the guardianship problem--at a place where they don't care much about having direct contact with the parent. For an immortal, it's only four years... [Answer] Settle in an area. (location 1) Fake pregnancy after "birth" relocate to location 2, but maintain original address (location 1). Visit location 1 frequently and tell people how your daughter is growing to be and doing well at location 2. Take steps to look older. (put on some weight, dye hair with hits of gray) return for good 18 years later as the daughter (change appearance slightly) Dye hair, do makeup differently.) Enroll in college and graduate to fully establish daughter's identity. Start new job. Report news of mother's death who is living in location 2 Repeat. [Answer] # Move a lot Our world is pretty big, and there are a lot of places you could live. There are 6 million or so people in the metropolitan area I live in. If you moved around every 3 or 4 years, it would be pretty easy to never run into the same people. If you move from city to city, there is almost no chance people would be able to track you. Without internet (and Facebook), you could just move from city to city every 5 years, keep in touch by phone with old friends for a while maybe, but then just naturally drift apart. The biggest challenge would be managing your id. If you lived in a place like the US, you'd need to reforge a new Birth Certificate every 10 or 20 years to avoid suspicion. I would recommend emigrating and then re-immigrating every decade. Go to Germany, forge an identity as an immigrant from the US, then go to Australia, then Canada, then back to the US. [Answer] Unless in your story people need to register with the authorities, there's really not much of a problem. The easiest would be if she is reasonably wealthy. She would just need to move to another city every 3-8 years. Cities should be preferable over towns or villages because seeing a stranger there raises no questions. She could attend university. Noone would question that she moved there to study. If she has to work for a living, she should seek out lower paid jobs that don't require (much) expertise, to avoid having questions asked how she can have 80 years of experience when she's only twenty years old... She must of course learn to hide her true age. If she doesn't talk much, or acts a bit dumb, that might help covering things up, and a simple but credible cover story to tell those poeple she does have contact with should be easy. Being female and 20-ish will help her greatly. Some biological hard-wiring in half the population's brains will ensure that there will be plenty of people willing to be friendly and possibly protective towards her. Not trying to sound sexist, but any sexual animal works like that, and humans are (among other things) just that. So, credibility of her not being caught out is high. I guess for the purpose of a story there's really not much explanation required. [Answer] Is there much magic in the world or just this curse? I would say she needs to keep traveling. Keep exposure among the same people to a minimum. Never tell her age, to keep people guessing. That way she'll remain active, just not in the same community. Be a trader or something, perhaps a traveling doctor. Friends will notice after a decade I'd say, perhaps two. During that time you can get away with looking roughly the same if not great for your age. I suggest changing you looks in between as well to make comparising harder. I think a decade would work for larger communities as well. Although you then run into the issue of being well known in the area. Moving to the next city won't cut it anymore. You'll need to move further then when you move more frequent. [Answer] You could always do what they did in the film ["The Highlander"](https://en.wikipedia.org/wiki/Highlander_%28film%29): * Keep forging documents to show that your character had a child * make a will and leave everything to that child * fake your own death * assume the identity of the child * repeat process [Answer] **Observable similarities** are probably the easiest problems to solve. A hair-dye / new hair cut, a few wardrobe changes, and moving to a new city will solve your problem of someone observing you. Of course, this means never forming long-term bonds. You'd have to maintain only casual acquaintances at most, as you'd need to sever ties every time you relocated. And no facebook or similar social media connections, either. You'd also want to minimize your odds of being recognized later. So you would need to avoid events that might be photographed or televised. It would be a bit uncanny if some B-reel footage of historical event X had you in it, and someone was like, "That person looks just like you!" No getting involved in big political rallies or buying front-row concert tickets. A low profile is the way to go. **Wealth and possessions** would be a bigger problem. You would need to have some sort of "foreign corporation" or blind trust or something that owns all your real property. Stocks, bonds, houses, etc. on multiple continents. You'd need to build a dizzying array of holding entities so you could, eventually, return to that property later and not be a penniless vagabond. You'd also need some carefully hidden archives to track where and when you've lived. Wouldn't want to accidentally return to your posh, NYC apartment too soon. You'd need to have several law firms on retainer. They'd need to be in the dark, too. But they'd be responsible for managing the properties, hiring servants to care for them, etc. And for managing your trusts/holdings. And for adding and removing temporary identities from the trust so you'd have money when you needed it. You would want to have stashed things on multiple continents, so if something goes bad, you can run to a safe-house and not be stranded without money or passports. You'd want passports that were fresh enough to be usable, in case events required a hasty exit. **Legal identities** would be the hardest part. You'd need to come up with a way to generate legal documents every time you moved. For a new person. They'd need to be more than just fake papers, too. We're talking basics like drivers licenses / passports / social security numbers (or equivalent in other countries). Because those are the basis for owning things. And for building a credit history for that identity so you can then pass background checks and travel freely. You'd probably have these identities employed by your fake corporations to justify the income levels. So you don't have to pass the kind of background checks human resource departments conduct -- you don't need valid college credentials or past employment history that is real. But you need to make sure that you won't be stopped at national borders. Or if you are, that your papers will pass official scrutiny. So they can't just be forged documents. **Self control and planning are key** to the above things being built out over time. And for maintaining all of it for the long-term. Rash decisions and poor planning would be costly mistakes. From time to time, you would have to shift ownership of subsets of your possessions from one trust to another, from one law firm to another. Have your existing lawyers sell that NYC penthouse to an unnamed buyer (with hints that it is someone famous who doesn't want to be bothered maybe?) from a fresh, new, major law firm hired by you under a different identity. That corporation that owns your some part of your business interests is bought out in a hostile takeover by some new corporation (that you also own). This way, you can close out the books and there's not some strange paper trail that goes back hundreds of years at that one law firm. Because your lawyer might get curious and learn too much. And you'd have to watch all of these things, somehow, to make sure you get out of some bad investment before it goes under. Or that your possessions don't vanish from under you. *It would be a hard, lonely, job.* [Answer] Relatives would be the first to notice the anomaly. The solution to keep this curse hidden is to be often on the move and keeping a number of close relative as near as possible to 0: 1. settle in a place 2. present yourself with a credible story for not having a family. Looking 20 this may justify she is a student or living on her own. 3. live there some years, like 3 to 5 years. 4. move to another city, better in a different country (she can learn the language while in the previous city) it would be wise to retire from civilization, like living in the woods, from time to time. [Answer] Since your world has magic, why not establish that she has acquired a spell through a contract with a monster? The spell would cause those who know her to always forget how long they have known her, or perhaps it may rewrite their memories of meeting her such that her age remains consistently explicable. Of course, you would probably need to ensure that there is a price to pay for her spell. And I suspect she may therefore be always, in some sense, isolated even amongst friends. [Answer] **Live somewhere where there are few people of your ethnicity.** Women can already pass as a wide age-range depending on dress/etc. White Brits are even worse at guessing the age of an Asian lady. This will allow you to stay as one 'person' for longer, and will also explain why no-one's met your daughter who lives back home, etc. and will allow you long absences to 'return home' to cover anything you need to get up to. [Answer] You know that wealthy Brits didn't seen their kids for 20 years? After they were born the parents went to India, the kids stayed with nannies and teachers and after 5 years when Mom and Dad came back the kid was sent to some prestigious school for 10 years. After that it attended Oxford. So when *John Biscuit the second* was in his twenties he came back home and his parents said "Ohh, I can't stand this spoiled brat!" and went to die in some African safari. So being unnoticed as immortal would require 2 to 3 mansions and a little bit of cash for expenses. You could do the Beyoncé cushion baby trick: Send the not existing child to schools or take it with you for some travel and then 20 years later come back as the heir. From time to time your not existing mother would need to die in some travel related catastrophe and sometimes you would need to keep the correspondence with her while she is looking for gold in remote Himalayan mountains. Looking young is not a problem unless you add avoiding people, sun, food because then they will call you a vampire. Remember that frequent travels and close relations with shamans and ancient magical substances (you encounter during your journeys) keep you looking young far in your 40's. I don't know in what times you want your book to take place but further into our times and future it would be easier to forge the generations. You and your mother could be seen at the same time "hey, we have a photo together", while the mother is on a business trip to New York her mother is attending a formal dinner in Kuala Lumpur and the instagram photos show us the youngest taking sunbaths in Greece. [Answer] People don't look too different between 20 and 35-ish assuming they aren't in the sun a lot or doing something really stressful, so for the first 15 years or so she probably doesn't have to do much, other them maybe pretend to have skin treatments or healthy eating to make the whole thing more plausible. After that people will start to notice, and if someone still looks 20 at 45 that's pretty suspicious especially to close friends. At that point she might have to move and start a new life somewhere else if she wants to preserve the secret. In general, she'd have to live off the grid as much as possible, so no bank accounts, no jobs that require background checks etc. I'm assuming without cars there are no driver licenses, but if they have an ID that has to be renewed every few years, that'll also start being a problem eventually. The trick will be use the "free" 15 years to earn enough money to be able to afford the move, the bribes to officials for fake documents and so on, all while being unable to present a lot of past experience/education to a potential employer without some shenanigans. [Answer] For finances, put everything in corporations in trusts. Then you can change the owner of the trust. She could probably make it to 50 years old without drawing too much attention. So, she should plan ahead. Raise a daughter, keep her in the loop and at some point switch places with her or her granddaughter. Have a big family and become the secret patriarch of that family. You can't do it without help and family can be the best help. Go around saving children. You never know when that might come in handy in the future. [Answer] Not sure the extent of what your magic system can do, but since I assume it's fairly strong based on: > > You first have to set a contract with magical monster in another dimension, and then you have to defeat him in a fight. > > > The following would probably work unless your character doesn't want people to think they use magic. This also depends on the time range of your work ("I'll worry more about it in 80 years, [which is later than when @Herlyks is covering], when I should be dying of old age" as an easy out unless you think of something along the way). **Claim to use magic to "appear" younger.** Maybe she can claim she beat a pretty weak magical monster that doesn't give much magic ability, so that's all she can do. If going for a longer time range than a lifespan (*hiding in a cave for 100 years option in question seems to imply this*), perhaps people will lose track of her real age and just be "She's older than she looks". Unless people who know her real age before her curse and keep record of it or something public records are being kept (i.e. a picture of a person in an encyclopedia showing they were at an event 200 years ago) happen. As for heroics, having her assume a "Dread Pirate Roberts" (but in actuality actually be a long living single Dread Pirate Roberts) is an idea. *Sorry if this post seems like a mesh of ideas, as I kept editing throughout* [Answer] Check out Oscar Wilde - "The picture of Dorian Gray". In this very famous book, the protagonist doesn't age as a picture of him ages on his behalf. He is not explicitly mentioned to be immortal in the story (and that's not the point of the story), but nobody really takes exception to his not aging. [Answer] **Anonymity** You do not have to move around a lot if you look average and do not befriend people who are curious about you. Instead, associate only with self-absorbed people and never volunteer information about yourself. I have heard stories about a very successful resistance fighter during World War II who was never arrested, never noticed, because he looked decidedly average. He was always just some random bystander. ("Kjakan" in Norway). You would need to move around every once in a while so people in your immediate surroundings don't start to notice you, but looking average you might not need to move far. (I believe "Kjakan" kept moving.) Your main problem would be if there is a government with a rigorous personal identification system. You'd then have to steal identities at regular intervals as others have pointed out. You'd minimize the need for this by avoiding every activity that requires identification. So, you would be self-employed, but employ yourself through an (infinitely lived!) corporation rather than a personal firm. If you're in luck, that same corporation could turn your identity over for you and fake your documents for you, depending on how the identification system is set up. Come to think of it, you should have several people hired at your company, all of whom are you, but there's a newly hired young you (previously unemployed) and the old you. Then you eventually hand the company over to the young you when time comes and hire a new young you. [Answer] An average woman can hide about 8 years if their genetics are good for that and they try, taking the right care. That would be a good excuse. The oldest woman the youngest looking right now (I read a new about that a week ago), is 56 and they say she looks about 18 (I'd say 23), so there are certain cases where you can hide your age for way longer. There's also another way to solve it, make good friends leaving for a long time and meeting them again, when their memory of you is less. Also... Do you know of ninjas? One of ancient ninjas (the real ones), specialties was disguising, specially kunoichis. They had already developed make up along ways to look young old, regardless their age. With enough investigation and resources, she'd just be left to fake death about every 60 years, since in that alternate version of a world, the average age would be about the same, if we take that chemistry is just slightly less advanced than in real world (because of lack of networks and fast travelings, investigations would be way slower, but if it was more efficent in that world, they might have the chemistry and hygiene that keeps us alive and younger looking for a longer time than when the fastest travel ways were horses, bikes and ships, just that they'd have different names every few KM. In some of the stories I make for my games, there appeared inmortal, unaging and all sorts of this kind, but I never thought about someone wanting to hide it for long. In one of my lastest stories, there's one who doesn't want to tell to anyone, but it's not something that can be hidden for so long to the other main character, since the other main character lives in the same house and refuses to leave. [Answer] Once someone is immortal and in a modern-like society, they can probably become pretty wealthy through investing. Thus our protagonist doesn't have to stay in one place. She could get a job that required travel. Consider, however, that in a magic society, there could well be "make me look younger" magic. It would be a hit with men and women alike. Like makeup, wigs, and cosmetic surgery is in our society, it would probably be rude to attempt to negate this. In that light, the very unusual "make me look older" magic would go undetected by polite society. She could fit right in without too many issues. She could still count on a solitary life. On the first few dates, "MMLY" magic would be ok. But at some point, the relationship gets serious and both parties would drop the charade. She could not go that far. She'll probably have to be satisfied with short-term romantic flings and meaningful platonic relationships. Issues arise when she's 116 and still paying taxes. Anti-fraud investigators will see that she's way too active for someone that age. They will assume identify theft. So once every 80 years or so, she must "die". "Did you hear about poor Mary? Her sailboat capsized..." Over the years, she must squirrel away part of her fortune so she can use it later without leaving a trail. Or she can live modestly and not care much about investments. A few million in gold can get a person past some lean times. She'll have plenty of time to figure out how to game the "birth certificate" problem. Oh what does it matter if everyone knows she's immortal? [Answer] No movies comes to mind? So she is almost like witch from > > Stardust > > > However every 10 years or so, she will has to move. If she lives in seclusion/periphery, it would be much easier. (Well i think if u move back to the place in 40 years, no one would notice) > > Twilight saga > > > And she will learn certain skills that helps her survive/hide. > > The Man from Earth, Doctor Who - Ashildr, Captain Jack > > > Or she will convince others that she is a god - because of skills and understanding of technology. > > Star gate - goa'uld > > > And if she "cannot die" -> she will be master of magic (and everything) in your world and she may became legend, even if she is total dodo. And also: "Omg you look exactly like Cleopatra" - do you think ppl will actually think that you are sane, if you try to convince them that you really are? ]

[Question] [ In which wilderness area on modern-day Earth would it be easiest for a lone human to survive year-round? What resources are available there and what tools and skills would be necessary? What is the approximate minimum age necessary for this person to survive there? Now. that being the essence of the question, there are some caveats: * This person will not be attacked by hostile creatures regardless of whatever creatures that are potentially hostile to humans exist there. Lions or tigers or bears, etcetera...? Not a problem. * The person in question begins with no special clothing, and can be assumed not to risk suffering from sunburn or Vitamin D deficiency. * They will initially have no tools, and must make any tools required from local resources. * This person will have the necessary skills and physical prowess to survive in the chosen location, however I would like to select the location in order to minimise the skills necessary. * This person may survive by any necessary combination of hunting and gathering using only self-made tools of any complexity achievable by a lone human with no external assistance. They may be assumed to come pre-prepared with all the necessary skills and training, and need not learn new skills in-situ. However, they will only have the minimum skills required, as per my previous point. * Regardless of any other physical abilities this person may need, they will have a level of health and fitness that will make [persistence hunting](https://en.wikipedia.org/wiki/Persistence_hunting) a viable option. * I would like to minimise this individual's initial age. They may be assumed to have the necessary skills and mental discipline to survive in the selected location regardless of their age, so please treat age as a purely physical limitation rather than a mental and physical limitation. * Any wilderness on modern-day earth may be selected provided that it has no significant permanent human population. What does this have to do with *world* building? Nothing in itself, other than the presence of this character who would otherwise not be there, but the location affects how the story may potentially develop. Answers to this question will serve as a starting point from which a different world will be built as the story is told. A person surviving by fishing in a tropical lagoon starts a story rather differently to one where this person survives by hunting and gathering in a temperate forest. **EDIT** What do I mean by "no significant permanent human population"? Pretty much that the person in question could go unobserved there by other humans (*not* that they may not observe other humans) for a period of at least one full year. Also, areas with below-freezing temperatures are not off-limits as long as there is sufficient time and resources for an unprotected human to fashion the clothing necessary to survive such conditions. They may be considered to start with shorts and a T-shirt, but - especially considering their youth - may either wear out or outgrow these, and *if necessary* replace them with whatever they need and can make themselves. [Answer] **Any Temperate Rainforest** [](https://i.stack.imgur.com/G1NFB.png) As a previous answer says, **Ireland** would be a great place, but there are several other similar areas in the world: northern **Spain**, eastern *Black Sea*, **East Asia**, the **Pacific Northwest**, and **southwest South America** all have one thing in common: they are temperate rainforests. **Ample Food** Tropical rainforests, which many other people have mentioned, have one big problem: [](https://i.stack.imgur.com/8nDq8.jpg) You've mentioned that the person in question won't be attacked by animals, which can be a problem in the jungle, but there's a second animal problem with jungles. There is a distinct lack of prey appropriate to humans, with a large amount of prey that is definitely inappropriate for humans, either via poison or simply too much effort to catch. Temperate rainforests lack this issue. Not only are poisonous animals rare, but game animals, such as deer, rabbits, game fowl, or tahr, are common, with the exact type depending on which area is chosen. Taking down an elk is one of the best meat sources a hunter can hope for, and you won't find those in the tropics. **Water, Water Everywhere** Not only is game common, but you'll notice that the vast majority of temperate rainforest on the planet is near a major water source. Nearly all of these areas have significant supplies of fish and/or seafood. Not only is the water a great source of food, it's a great source of, well, water. **Mild climates** You discount weather, but the majority of these areas have warm summers and cool winters, rarely venturing into "cold" or "hot" territory. **Other Considerations** Despite the mild climate, you'll still need shelter. Fortunately, temperate rainforests have excellent species of wood for use in structures. You only mention hunting, but if your character needs to get into farming, these areas also happen to have some of the most agriculturally viable soils on the planet; getting food to grow in any of these areas is surprisingly easy. [Answer] As a native I'm definitely biased here, but Ireland is actually a pretty good bet. [](https://i.stack.imgur.com/uo6JJ.jpg) Especially towards the West, Ireland has actually seen a decline in rural population. You can genuinely walk for miles and see no signs of civilisation. I'm talking even the grass has no footprints. Predators? Ha! St Patrick took care of our snakes, and our beloved English settlers long ago wiped out the major predators whilst leaving plenty of game like elk and hare. The forests (especially near the mountains) are littered with flintstone. Littered. You'll have no problems making tools or shelter. All deciduous trees (like Rowan or Birch) can be used to create strong and sturdy structures if you need, or great firewood. The western Galway coasts are a little harsher (gale winds mostly) but the abundance of marble caves will cover you well. [](https://i.stack.imgur.com/72TO5.png) If you're a Game Of Thrones junkie, you may recognise this little place. It's in Fermanagh, a two hour drive from the nearest city (which has a population of less than half a million people). On that note, King's Landing (Port Ballintoy) is on the north tip of the island, where only 300 people make up a 100 square mile area. Weather is famous, but the jetstream means you have no shortage of rain whilst also not freezing to death. So, why does no one live in these unsullied spots of paradise? Fun little bit of Irish culture. Most of this (and the last two) generations have moved to the three major cities (Cork, Dublin and Belfast) in search of better prospects and good steady work. We have world class universities and every Fortune500 company across these cities because of this odd intellectual exodus. People living on the outskirts tend to be people's ma and da or farmers- "culchies". They're kinda like our version of hillbilly's. They're not hugely active, so rarely leave the house. They're also generally old and wealthy or lifetime farmers, so they're not seeking any kind of economic growth. With little technological infrastructure, companies just aren't interested in setting up in the rural fringe, and employees aren't interested in saving a few bucks for a three hour drive, 9 to 5 (no transport links either). What's resulted over the past 100 years is genuinely unspoiled mountain ranges, valleys, coasts and islands for miles to go. You can't use Google Street View on 60% of County Galway- try it for yourself. It's one of those weird places on Earth that no one lives in, but is much more than liveable in. [Answer] I'd suggest Hawaii. * No large predators - biggest things are wild pigs, which generally avoid humans * Fresh water, both from rainfall and from mountain streams * Plenty of edible plants which grow year-round * Weather is warm, but not too hot - shorts and a t-shirt are fine, but cold isn't a problem if you do outgrow your clothes * There's a large enough wilderness area that one could pass unobserved for a long time Given these, and given that you have "the necessary skills" already, you could survive at almost any age - there's not really anything that requires a large amount of physical strength. I'd say minimum would be something like a six-year-old who's gone wilderness subsistence camping in the past with their family. [Answer] in my opinion **tropical jungle/forest island with lagoon** (its quite common not rare) preferably big (high chance to be because of current global warming drown the smaller one). * **you wont encounter winter**, you wont get frostbite, or chance of death from the extreme cold (unless you are near a hill or high mountain site of the island which is colder while in heavy rain) so no need for thick clothes even no clothes! and use animal fat or spice to smeared your body can be sufficient enough from bug bite/repellent and warming your body from the cold, also usually theres many growing type or variety of wild plants that can become a natural repellent to certain insects such as mosquito (most of them also can give extra flavour for cooking ingredients), either just being there or processed, like turn into incense or chop or squeeze till it give stronger smell or dropped oil to smeared over your body, also mosquito usually active at night, since the comment mention malaria, not all mosquito bring malaria the type that give malaria only grow in dirty water, so you can try to drain or keep out from such place and even as a child you still can survive, it still depend on your immune systems, how quick you are treated with the natural herbs, and also coconut water can help increase the platelets, i myself have struck by malaria as a child so this is more on personal experience, although i dont know the other herb ingredient except coconut water, and even so, you can cure yourself only from drinking coconut water alone regularly while let your immune system do their job, i was cure like this. also if you want cloth or a blanket or some small protection, or maybe a mosquito net for easier sleep, you can made it either from [certain tree bark](https://www.youtube.com/watch?v=qY9SmGs-TTo) or [banana tree fiber](http://en.sanyatour.com/news-media/news-media-sanya-news/banana-clothes-a-stylish-heritage-clothing-of-hainan-li-people/) or from wild cotton tree around. * **rain is quite often happen and is a blessing for water source** if the location lack clean plain water but only until you already build some shelter to protect yourself from the rain and other elements such as from sea wind or night cold and theres plenty of resource to build from, you can even just dig a hole cover it with variation of leaves and stick or mud and clay as roof (preferably dig in clay or hard soil area) and be done with it, and just can go to other place if it got filled by water (at least it can become a water well to collect rain water) if you want to be quick or a lazy type or not permanent shelter, here some video how to build underground house by using primitive hoe or wooden stick or rod stuck with sharp steel/iron (which i believe can be replace with sharp stone similar like stone axe) so not require an elaborate digging tool [Dig To Build Secret Hidden Underground Tunnel House In Deep Jungle](https://www.youtube.com/watch?v=JEmklUGQHBc) but its not require to be that big though, and even so, you can get water from the plant there like [coconut, roots, vines, etc](https://www.seeker.com/how-to-find-clean-water-in-the-jungle-1765355301.html) if no water spring nearby. * **abundance of stable food variety including wild spices and access to salt**, as long you know the safe local food or edible parts (either animal including fish, insect, and plants), and how to safe cook it, example like wild cassava root which is poisonous, considering there also a lot of poisonous or toxic type, and salt can give flavor and help preserves food assuming you character know how to get it from the sea or the shore rock, outside of smoking and drying method, basically you has lots of delicious cooked food options due to the abundance of wild spice variety, while can also make insect palatable (my advice, dont eat it RAW, cook it, but dont cook it like you cook marshmallow on campfire.). * **and you can just try to farm there**, if you got tired for scavenging food most of this type of land usually contain high fertile soil, or you can plant more coconut (coconut definitely everywhere in tropical islands i can assure you) by dumping some coconut around preferably in the sand or the shore, no need to tilting the soil if you are lazy. * **also have chance to get out of there by building boat or raft** yourself from the resource there base on the answer of @EDL from my past question here the copy paste of it. > > The explorer Thor Heyerdahl built his vessel out of balsa and sailed > from South America to Polynesia > > > [](https://i.stack.imgur.com/4WArI.jpg) **even child in here can survive as long they dont encounter wild beast**, and when i mean child, i mean 6-7 years old as @Skyler also mention it. **the problem is health or disease**, so you need to know local or herbal medicine, but since you say the person is fit, its not really a problem to your character (i mean in health) except disease (depend on the person immunity especially if the character is native or not, even so not all disease have traditional cure or require materials from other regions, but thats generally the same problems regarding isolated place whatever you land in around the world). **storm** (i mean the hurricane or tornado type of storm) is not that common unless you are near philipine islands, i recommend pacific island (still have chance for storm and island drowning) and indonesia (both border with australia if you dont know the location) plenty of unnamed desert islands even today and most of them is decent size or quite big since the small one mostly drown already because of global warming..., which still have plenty of the thing i has say, but this kind of place especially indonesia also usually near ring of fire so earthquake and volcano eruption (including underwater) and tsunami is a possibility, unless the island is around borneo island which safe from all of this except man made disaster such as smog from burning rainforest for palm oil plantation, and sorry cant provide exact location as been state its unnamed islands not even include in current world map and its many, most that already name or being known by outside specifically from indonesia is turn into tourist place, and the named one is numbers 16.056 total according to google alone and keep increasing. ps:if people wondering why theres a lot of unnamed island the hint is the [ring of fire](https://earthobservatory.nasa.gov/images/82607/new-island-in-the-ring-of-fire) so after surfing around in google, i found the rough map regarding surveyed island around indonesia (the red dot) [](https://i.stack.imgur.com/Vwkbr.jpg) and further information [also its now 17.504 islands totals](https://unstats.un.org/unsd/geoinfo/ungegn/docs/11th-uncsgn-docs/E_Conf.105_115_CRP.115_Agenda%209a%20Identification%20of%20Islands%20and%20Standardization%20of%20Their%20Names_BIG_Indonesia.pdf) and here location of volcano you may or may not want to live near there, since the island near it usually is also fertile lands. [](https://i.stack.imgur.com/L1f49.gif) also indonesia is quite big so the people rarely live in the desert island, and it mostly turn into tourist location or for pasturing. **and conclusion**, i still recommend to take islands (any red dot you like) near borneo islands (the big island in the middle, border with malaysia) especially the west side, it safe from all natural disaster i have mention so far except man made. [Answer] Ironically enough I think your biggest problem is going to be finding actual wilderness on a modern day earth that is arable and amenable to habitation for what are obvious reasons; if it supports life, we've already inhabited it in large numbers and probably put concrete and warehouses over the most arable land, pushing the farms out to less hospitable areas in the process, but I digress. If you take animals out of the equation, the two most obvious places are Africa and the Amazon. As a child I got so used to seeing pictures of starving children in Africa on the TV that I just assumed that it was a desolate place. It turns out that this is very far from the truth; most of the time, Africa is a highly fertile and productive land with good climate and it grows food that humans can eat without any real intervention. Most of those famines I saw as a child were a consequence of population increase and a lack of cultural experience with storing away for lean times that comes with a climate in which there is always something to eat around you. Europeans for instance know all about storing away for the winter and saving for lean times because of how hard it is to actually grow crops in European winters. In the modern world, famines in Africa still occur but not on the scale that we used to see and most of them are now related to conflict in one way or another, and the impact that has on modern farming techniques. The practical upshot of this is that all the really fertile lands where human foods would grow wild in Africa are now pretty much populated. On the other hand, you also have the Amazon Rainforest. Lots of biodiversity and native groups are living in it already, pretty much untouched by most of human civilisation but that is changing. The problem is that again the land is fertile and once cleared makes great farming or pastural lands, so encroachment by modern farmers, loggers and others is reducing the amount of natural wilderness that one can find in that area. Ultimately, you're writing a modern day jungle book, in a world where jungle is in increasingly rare supply. But these are probably the best two candidates for what you have in mind. [Answer] "Any wilderness on modern-day earth may be selected provided that it has no significant permanent human population." That is an issue ... Leaving existing population out, you'd want the temperate bands around the equator to avoid extreme cold. You'd want coastal, or at least affected by coastal weather patterns to provide plenty of rain fall so no desert areas, etc. No islands in the Caribbean or Pacific or Indian seas due to storms, etc. and simply not being large enough to sustain a person via foraging/hunting/fishing. So think about the middle third of the world, running in a stripe with the equator at the center. Now remove desert areas, and islands. Plenty of good places left - both coasts of Florida, a good bit of Central and South America, the Gulf Coast of the US except Texas, parts of S. Cailifornia and N. Mexico but watch the desert issue, and that is just a little bit of the land mass left. Unfortunately, when you add the "no human population" none of those areas qualify on modern earth, and any place that does is extremely un-inhabitable. [Answer] If your protagonist is not going to be attacked by animals, go to a rainforrest. By staying close to the Amazon river you have a practically infinite supply of fresh water all year round. Temperature is also constant throughout the year. There are enough animals and plants to keep you fed. Shelter won't be a problem, you can find a cave or build your house by the river - plenty of plants of all kinds for that, indians have been doing it for millennia. If you wish to grow your own food, just open a clearing in the forest. Most of the indians there are farmers, not hunters. Last but not least, if you have a herbalism manual, you will be inside a living pharmaceutical lab. Need some medicine for whatever condition? There will be an animal or plant that will suit your needs. I know of [a vine that people use for fishing because it stuns fish](https://en.wikipedia.org/wiki/Serjania), leaves that reduce fever and pain, [DMT containing plants](https://en.wikipedia.org/wiki/Ayahuasca), [a fruit that is practically Red Bull in solid format](https://en.wikipedia.org/wiki/Guarana), [a plant whose leaves and fruit you can eat to alleviate anxiety and insomnia](https://en.wikipedia.org/wiki/Passiflora) and [a spider whose bite will give you three-days-long erections](https://en.wikipedia.org/wiki/Phoneutria). Seriously! [Answer] ## San Nicolas Island [San Nicolas Island](https://en.wikipedia.org/wiki/San_Nicolas_Island) is part of the Channel Islands of California. The weather is lovely year round (some rain but no extremes of temperature). [](https://i.stack.imgur.com/23KMk.png) *(By Lencer - own work, used:Google EarthUSA California location map.svg by User:NordNordWest for MinimapIdea: Californian Channelislands.jpg by National Oceanic and Atmospheric Administration, CC BY-SA 3.0, <https://commons.wikimedia.org/w/index.php?curid=6444044>)* People lived there for 10,000 years and did quite well. There's plenty of food and water and enough resources to make tools, shelter, and clothing. When the native people to the island were forcibly evacuated 200 years ago, one young woman was left behind and lived there alone for 18 years. This is a quite famous story which was fictionalized in the popular middle-grade (children's) novel [Island of the Blue Dolphins](https://en.wikipedia.org/wiki/Island_of_the_Blue_Dolphins). In the book she starts off as a teen but it's unclear how old the real life woman was. In the last 100 years or so, the island has not been treated well. The ecosystem was ravaged by sheep (removed in 1943) and cats (brought by the navy in the 1950's and now eradicated). If it is abandoned in your story then there may be tools and materials left behind your character can use. There are multiple other islands that are part of the [Channel Islands](https://en.wikipedia.org/wiki/Channel_Islands_(California)) of the Los Angeles/Santa Barbara coast. Of the 8 islands, only one, Catalina, has a permanent population (it also has significant tourist trade). Not only would some of the other islands also be good choices for you but, once your character has built a boat, s/he can travel among them. It would be very possible for other humans not to see your character for at least a year, but also possible to be found, depending on your plot requirements. [](https://i.stack.imgur.com/vtIVn.jpg) *(By Toddclark, CC BY-SA 3.0, <https://commons.wikimedia.org/w/index.php?curid=6045926>)* [Answer] **TL;DR**: Just choose a wild area that has several kinds of easily gathered wild edibles, and put your main character in a spot that is naturally filled with them. Then surviving is as simple as grabbing whatever is currently growing on the vine or hopping by and anyone old enough to walk and put thing in their mouth is old enough to survive it. --- Given your personal meaning behind "wilderness" - that is, "nobody will notice me for at least a year" - the actual, simple answer to your question as asked is "any spot that you can easily hide in which is near a good food source." As long as the person tries to hide, which is likely if they are scared of people or if they had "stay away from strangers" instilled in them before they lost their parents, then it doesn't take much to stay out of sight. A stand of trees, a few bushes, a field of tall grass, or any combination of these or similar features. ## Wal-Mart fits your criteria... no, really There is a field right next to my local Wal-Mart that technically fits all your criteria. A fence at the edge of the parking lot has an overgrown field on the other side of it, including trees. It would be easy to live there indefinitely without being noticed. A person could take from the trash and dumpsters at night, or they could grab food from peoples' cars at the edge of the parking lot when the people are returning their shopping carts. If the person is specifically hiding, they could go a year before being noticed. Especially if that spot of the parking lot is a blind spot for security cameras. ## Near Agriculture But I doubt you're looking for a dumpster-diving main character. So instead of a hiding spot near Wal-Mart, pick one near agricultural fields. I have in mind right now a perfect spot with thick trees and bushes that is literally a stone-throw away from an apple orchard, and the layout is such that nobody would notice someone coming out after hours. And apples are a fruit that can be stored for months. Some people bury bins full of apples to store them long term then dig them up when needed. You could insert any other food source in here as well. A feral child could be found because it is stealing too many eggs from the farm's chickens, for example. With either the Wal-Mart dumpster-diving case or the nearby farm case, as long as the weather is mild enough or there is sufficient protection from the weather, a child old enough to walk and take things is old enough to fit your criteria. So 1 or 2 years old perhaps. ## Wild Food If you don't want the person relying on civilization, but rather want them relying entirely on wild, hunted or foraged edibles and what they can grow themselves, then your best bet is to drop them into an area with a variety of easily picked wild edible plants that are ready at different times. The tricky part here is minimizing large gaps between harvest times. The best spot I know of from personal experience has lots of wild berries and a wild pear tree. The wild berries and pears are both smaller than cultivated varieties, and they don't taste nearly as good, but they are ok and definitely edible. The same area that has these also contains a few varieties of edible weeds, including a variety ready to eat in early spring, and a couple varieties of edible flowers. It also contains lots of mice, frogs, snakes, snails, bugs, all edible. If I just walk around a little bit I have lots of frogs jumping away from me out of the grass, and they are easy to catch. It also has the occasional rabbit, raccoon, or other small edible game, which I have caught. I actually bought the land in question partly because of the natural abundance, and I eat a lot of the wild food from it. It is in the north-eastern US. If your main character is dropped into a plot of land like the one I found and bought, they don't even need much skill to survive on it, it's extremely easy. And you said your preferred main character is the younger the better, so they don't need to eat as much either. If your main character is willing to eat meat raw (not advisable, but definitely possible), then they could literally laze about and just pick something edible nearby whenever they want. If they are willing to eat everything edible there, then a child 2 or 3 years old could survive there. So the most interesting answer to your question (ie: avoiding dumpster-diving and farms) is to just pick any place that can have a variety of wild edibles and then say the character is in a pocket of extra-rich abundance. It's certainly possible, I just gave you a specific instance. And I highly doubt that plot of land I mentioned is the best on the planet. There must be thousands of millions of other pockets of wild land that are even way better than the one I described. The specific land I mentioned might sound too good to be true, but it does have drawbacks. Probably the biggest problem with that land is that it is infested with both poison ivy and poison sumac. This is extremely annoying for me, but it could be an interesting twist for your world setting in your story. For your story, to make it even more believable that a child could find the food needed to survive, you could also include a stream flowing through the area that provides water, small fish, crayfish, and salamanders. [Answer] **Ok so this answer is going to be both very general and very specific.** --- **The general part:** The key components for any location are as follows * Access to fresh water * Access to food * Access to natural resources for everything else * Ideally all these resources are as close as possible My recommendation to hit all these requirements the best way possible is similar to @Michael W.'s answer - temperate forests are the way to go. **The specific part:** I'd set up in this area right here. This area is west of Seattle and borders Olympic national park. So why here? * This location has two large freshwater lakes, providing easy access to fresh water and food in the form of fish. * Well forested, plenty of access to fuel for fires and resources for building shelters * The forest also provides plenty of access to game * The soil is plenty fertile for farming should your lone human make it to that point * The mountains are not terribly far away giving you access to plenty of stone, flint, and potentially iron ore if you want him to evolve his tech to that stage * Clay should be abundant around lakes and streams allowing for containers fairly easily. * Easy access to the ocean. Plenty of food to be had, not to mention salt from collected seawater/evaporation (humans need salt) [](https://i.stack.imgur.com/Xt6kn.jpg) [Answer] Choose the Galapagos islands ! The animals there are easy to hunt, because they do not fear humans and wont run away. There are no predators on these islands, also no snakes or other potentially dangerous animals. Only four of the 13 islands are inhabited, the biggest of them, Isabela has only a small population an is mostly wilderness. Temperatures are moderate year round, there is a dry season, but you should be able to find fresh water even in the dry time on the bigger islands. If you need a house you can build it out of wood and stone. You could make fibres for clothes out of agave which is common on the most islands. Of course these islands are a nationalpark and if you try to farm, hunt and live there, the park rangers will catch you some day and you will have to spend some time in an ecuadorian prison cell. But of course, what your protagonist is intending to do is illegal in every part of our modern world.. [Answer] Probably any high tropics, continental or large island coastal area. Warm year round, but not continually oppressive. The ocean is probably the easiest to exploit and most abundant source of readily available food. Access to the interior with fresh water sources, animals of varying sizes providing an additional source of food. Also a variety of fruits, nuts and other forage. Building materials. High ground to escape coastal storms. [Answer] I live on the West Coast of the US, and it's so mild (I'm in WA State) that I joke about not being able to live anywhere else. I'd go South from here for the BEST location, probably somewhere between Central Oregon and Northern California, far enough South but still in the path of the warm, wet Pineapple Express winds that make it wet and verdant all the time around here. <https://en.wikipedia.org/wiki/Pineapple_Express> If the character lives in the foothills of the Cascade Mountain Range there are lots of wild places. Lots of water, lots of edible mushrooms, berries, and nuts. [Answer] Lower Elevations of the [Tillamook State Forest](https://en.wikipedia.org/wiki/Tillamook_State_Forest), in Oregon. 364,000 acres of temperate rain-forest that you can easily hide and survive in for a long time. If you actively are trying to not be found, you are not going to be found in this forest. Lots of fresh water via rain, moderate temperature changes, varied edible flora and fauna. [](https://i.stack.imgur.com/9Q1Hg.jpg) [Answer] There was a fellow lost in Tasmania who lived on mushrooms and dew. I don’t know how long he was lost, but it was long enough that when he finally found his way home, they were about to start his funeral. Some hunters found him and showed him the way out. Prior to that, he had encountered no one. ]

[Question] [ Enter the [Insert cool and awesome Latin name here] - this species is 3 times the size of a lobster from front to tail, and a powerful hunter. Operating in swarms, they are my worlds equivalent of the piranha, except they don't really have any predators. [](https://i.stack.imgur.com/2SHv0.png) It has an armored shell, with shell-dorsal fins to stabilze its fast forward movement and a powerful, whale-like tail to give it forward thrust. The tentacles on the sides and front allow it to maneuver; by using them to spin, it can rotate and turn, similar to how a plane would roll to perform a turn. Not depicted properly is that the forward tentacles actually are sharp and tough, and can be used as weapons if required. [](https://i.stack.imgur.com/UoYs6.jpg) The Gills are on the bottom of the creature, similar to the manta ray, and the mouth operates like a crabs mouth. [](https://i.stack.imgur.com/6NYwO.jpg) However, the main issue I have run into is with its method of hunting. I want these creatures to dart forwards and ram into its prey, lodging itself into the subject before using its mouth and forward tentacles to rip it apart. [](https://i.stack.imgur.com/HPAdg.png) (Please forgive the poorly sculpted, unrealistic barbs) But I see a problem with this hunting model. I can't figure out a logical, proper reason (other than them lodging themselves into the sides of their prey to feed) that being attached to their prey would be more effective than simply having a barb-less horn, allowing the prey to bleed out by pulling out the horn, which also allows more stabs and more holes. Shrimp, which have barbed horns, don't seem to use them to hunt (or rather, I can't find any reference to them doing so, and have only vaguely seen mention of the horn being able to be used for "attack and defense"). Swordfish don't have barbs, but they definitely don't stab - they slash instead. While Dolphins ram using their tough noses, they don't penetrate to cause damage. Even humans have designed ships which sometimes have naval rams, but while they did penetrate other ships, they weren't designed to stay lodged in the enemy ship. Piranhas take bites out of their prey, they obviously don't stay lodged on them. # So the question is: What would cause an underwater hunting species to evolve a barbed horn, such that the purpose of said barbs is to remain lodged into the prey? Some additional information that may be (but most likely isn't) useful: * This creature can reach speeds of up to 90km/h * The creature can use echolocation * The tail, underside, and tentacles of the creature has a dolphin-like "skin" * The black dots on the front of the shell are eyes * All tentacles are able to retreat into the shell, similar to how the head of a turtle can be pulled all the way into the shell * The shell is very tough, and the horn especially dense. For the purposes of answering this question, you may assume that the horn will not break off. * This creature can hunt both in shallow and deep water. [Answer] **To be annoyingly clingy** Your super lobsters seems to have the ability to hunt *anything*. The barbs makes it easier for a team of them to hunt prey much larger than themselves. The main purpose of barbs is, as you state, to remain attached to whatever you are trying to kill. When hunting in a team after large prey, the first of the lobsters to ram it, and just keep attached to slow it down for the others to reach it. Others then do the same, and keep attaching more and more lobsters to the poor victim in a very painful but inescapable process. The usual defence for a big creature against smaller predators is to sling them away, and literally "get them off your back". If you can not make them lose their grip, you have a big problem. The super lobsters can just hang on and continue their strategy, in something that is surprisingly similar to a DoS attack, eventually breaking down the capacity of the target. [Answer] **Because you are a sprinter only (in contrast to your prey)** Some animals such as cheetahs are not capable of hunting a prey such as a gazelle for more than a few hundred metres. The gazelle is capable of long distance running. So their tactic is super high speed (fast land animal on earth) on super short distance, knocking down their target. Obviously in water you can not knock down someone - but as one strategy, you may concider attaching yourself to the target, and gradually kill your prey. Which matches your description! So an answer could be: attaching yourself to the target is the only viable way in water if you are a sprinter and can not kill instantaneously! Killing could be by venom, or the effects of the damage caused by the barb. Or both. Perhaps, your prey is simply orders of magnitude larger (think whale), so that effects take time. In either case, if instead the prey would get away, or die further on due to damage received, it would fall prey to some other predator, and the super lobster would receive nothing. [Answer] # They feed through their horn There are animals that already do this, the most famous of which are leeches, ticks and lampreys. They attack their prey, latch on, feed, then let go once they're either full or in danger. [Answer] **Co-evolution.** Think about the evolutionary context like this. 10 million years ago, an ancestor of [Insert cool and awesome Latin name here] (Icaalnh) would mostly kill its prey with ease using its sleek spike. The 'ones that got away' had denser fat deposits/thicker skin/swam faster than the primordial Icaalnh - and due to natural selection, these became the dominant forms - fatter and faster, less likely to bleed to death - and even if they did, would be likely eaten by other predators. Random mutations in spike growth lead the Icaalnh to in-turn evolve the barbed spike as part of the [ongoing evolutionary arms race](https://en.wikipedia.org/wiki/Evolutionary_arms_race). [Answer] It could feed as a parasite, always attached to its host, like a lamprey, or the exceedingly creepy [Cymothoa exigua](https://en.wikipedia.org/wiki/Cymothoa_exigua), which replaces a fishes' tongue. [Answer] Sounds like the super lobster is a fast predator (90kmph!) which means the prey is just as fast too. Its teeth and claws from the diagram would not be strong enough to catch and kill or incapacitate fast prey of equal or bigger size quickly enough before the prey got away if the super-lobster were to just bite or scratch. Especially if the prey has thick skin or is armoured. The barbs could have venom or digestive enzymes that act to either dissolve flesh spider-style. Maybe it's a leech-like creature that drinks blood, eats flesh and lets go when it's full. Maybe it evolves in a world of armour plated prey and needs the extra time to bore through the armour and deliver the killing blow. Lions and tigers do latch onto prey such as buffalo while hunting to weigh them down and allow access to the jugular vein. Crocodiles too latch on and wait till the victim dies of bleeding or drowning. Super lobsters are not so illogical. Cool btw, those diagrams look great! [Answer] It hunts whales. Like a tic, it would embed it self and continue feeding on it's host. If the host is large enough it's conceivable it could live a long time with the crab-tic attached. Or maybe once it digs in, the crab-tic could live in or just under the host's skin, not necessarily eating but more parasitical. Or ever symbiotic. Just don't let it attach to you head for a half life. [Answer] They might not feed instantly. If they didn't stay out long from hunting, it may be a valuable to be able to stab once and then be able to swim back to their nest (or whatever it's called) and eat there as opposed to a fight first. [Answer] **1.** A solitary hunter, the uberlobster could latch onto a fish with its horn, paralyze it with a crippling neurotoxin that it excretes from its body, and eat the fish alive as they fall to the sea floor. While the most brutal method in the list, it is not particularly effective against social animals, as other members of the school could simply pull it off the helpless fish or gang up on the uberlobster while it feeds. The barbed horn doesn't seem particularly easy to pull out, both for the lobster or the fish. Larger, solitary prey animals with coarse skin would be ideal to latch upon. **2.** Patient and cunning, the uberlobster simply plucks a little fish from its school near the surface, impales it upon its horn, and swim towards the deep sea, waiting for it to die. The barbs would keep the fish from escaping. As the fish has not adapted to its new environment, it will implode on itself. Somewhat time-consuming, though its incredible speed would easily quicken the process, but effective on the schools of fish mentioned above. For obvious reasons, this tactic wouldn't work on larger prey animals, as the uberlobster would not be able to drag it down. **3.** Simply put, the uberlobsters are the communists of the sea. While one pack member slows down and distracts the prey, the rest of the uberlobsters move in and go for the kill. They might either share the prey with each other or fight for the largest share. As other answers have eloquently shown, animals with strong, showy, and intimidating claws, crabs in particular, primarily use these to "settle disputes" with other members of their species. [Answer] In the animal kingdom, articles that often look like they have evolved for hunting are actually never used as such. In these cases they may be for territorial spats or fighting off rivals to protect or acquire a mate or mates. Sometimes these articles are less deadly than the primary hunting equipment of the animal so as not to snuff out a potential relative who carries similar genetics, or a potential source of genetically diverse offspring for their own future offspring to mate with. Even if this your creature does not use its gnarled horn in this way, it could be a vestigial horn used this way by distant ancestors. [Answer] **Poison!** Bee's sting you and leave their butt-sack attached, so that the poison can keep pumping into you. I don't know why the bees do this, because it seems they mostly die after this (so why not stay around?) Anyhow, super-lobster-Mk-VII injects poison through its horn, it would be able to take down very large prey if it stuck around long enough for lots of poison to go in through the puncture. [Answer] Enter the Eunice aphroditois or [Bobbit worm](https://en.wikipedia.org/wiki/Eunice_aphroditois). [](https://i.stack.imgur.com/1J7ib.png) This underwater invertebrate hides under the sand, waits for prey to swim over them and then shoots up and [grabs the prey](https://www.youtube.com/watch?v=3H4J5QDQeA4) with their massive jaws. They then drag it underwater and slowly devours it. Now while this 10 foot long monster worm is very different from [Insert cool and awesome Latin name here] (Maybe Gurgustium Venator Latin for Barbed Hunter) the principle is still the same. Have your species rely on hunted by grabbing and dragging their prey. [Answer] Cnidaria : Cnidocytes. These cnidocytes are activated in 10 ms, the deployment is considered rapid. This is a venom delivery system, however, its ability to secure objects is fairly prominent. From wiki: > > Penetrant: The penetrant or stenotele is the largest and most complex nematocyst. When discharged, it pierces the skin or chitinous exoskeleton of the prey and injects the poisonous fluid, hypotoxin, that either paralyzes the victim or kills it. > > > Glutinant: a sticky surface used to stick to prey, referred to as ptychocysts and found on burrowing (tube) anemones, which help create the tube in which the animal lives > > > Volvent: The volvent or desmoneme is a small and pear-shaped nematocyst. It contains a short, thick, spineless, smooth and elastic thread tube forming a single loop and closed at the far end. When discharged, it tightly coils around the prey. They are the smallest nematocysts. A lasso-like string that is fired at prey and wraps around a cellular projection on the prey, referred to as spirocysts > > > Specialized types can be used to stick or to envenom, it should fit your latching requirement if there are enough. [Answer] These sort of parasites hang on to every mammal in the sea and on land. They feed off the host and hang out, sucking its blood while it does all the work wandering and flapping and navigating while the parasite tags along for free. The parasite either injects eggs or drops off to do its own reproduction stuff. Maybe another idea, but very dark. Mammals such as dogs groom ticks all the time if they can reach them. So the ears and eyelids are favorite targets, as unless the dog has a grooming friend, the parasite won't be nibbled off, since the dog can't articulate to reach them. Alternatively, it could stick its fangs into the genitalia of the creature and hang there, while the owner is too afraid to do anything about it for fear of pain or losing his own reproductive potential. ]