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0 | ELI5: Why are PS4 and PS5 unable to read PS1 or PS2 discs? | PS1 and some PS2 disks are based on the CD standard. The drive in a PS4 (and I assume PS5) doesn't read CDs. Among other things it's only equipped with lasers for DVD (650nm) and Blu-ray (450nm). | [As far as I know, a lot of PS2 games were on DVD though. Based on this, I have a follow-up question ..?]A lot of PS2 games were on DVD though. Why can't the console read those? | Strongly Related |
1 | ELI5: Why are PS4 and PS5 unable to read PS1 or PS2 discs? | The disc producers aren’t able to recreate the same data they used for those discs as they do with current models, the PS4 and PS5. | [You mention recreate the data but don't explain the mechansims. Based on this, I have a definition followup question: ]This may be a lot to ask but could you elaborate on the process of recreating data? | Strongly Related |
2 | ELI5: Why aren’t there insects the size of man or larger? | They don’t breath the same way mammals do. They have tubes in various parts of their body that expose their circulatory system to air where it absorbs oxygen. Because they don’t inhale, they air limited in size by the amount of oxygen in the atmosphere. Which is why they used to be bigger in past eras when there was more oxygen in the atmosphere. | [One example of insect is roach, which is harmful for people. Based on this, I have a follow-up question on people deliminating roaches:]Is this why soap and water works in roach? It clogged up their breathing pores? | Slightly Related |
3 | ELI5: What is it that you see when you press your finger between your eye socket and eyeball, on the eyelid? | The light sensing cells in your retina fire off not only from light but also from pressure. When you press on your eyeball you increase the pressure inside of your eye which then causes cells in your retina to fire off. Your brain then interprets this as light. | [] So the black spot and light circle around it, is a reaction of the pressure, on the opposite side of the eye? | Related |
4 | ELI5: Why do words stop sounding like words when thought about too much? | When you say or think of a word (for example, “pink”), it creates a sensation in your brain. That sensation is electric impulses traveling from neuron to neuron in a specific, complex network that your brain accepts and registers as “pink”. However, during the travel of the electric impulse, your neurons release certain chemicals, and those chemicals need to be restored. This is known as “reuptake.” Thus, when you first think “pink,” all the neurons used to create that thought are all strong and ready to give you a nice, strong, comprehensive, and clear idea of pink. However, after immediately triggering those neurons over and over and over, while your neurons are still in the reuptake process, they get, “tired out” in a way, and aren’t all able to perform as expected. Duly note; neurons firing is like a gun firing; they either do or don’t. They can’t half fire and create a weak image. Instead, the idea of pink gets less and less clear as less and less neurons are working to create the image until they all “pass out” and you’re left thinking “...what IS pink?” | Side question: why would repeating the same phrase over and over lead to memorizing it if the neurons respond less and less to the stimulation? I know it's better to memorize a little bit over a long period if you really want it memorized. But in short-term, like a week, it seems like just wearing your brain out on it is better? | Slightly Related |
5 | ELI5: What are scripts in terms of code? | Typically a script refers to a small application written in a high level programming language that isn't compiled in to an executable file which typically automates a process rather than being an application that a user interacts with. | So like, say I coded a quick grade calculator in Python. That would be a script right? While an actual game in C++ that I could run would be a program? | Related |
6 | ELI5: Air weighs 14 pounds per square inch, yet we don't feel it crushing us. The notion that internal pressure somehow acts as a counterbalance just seems to mean that we're being crushed in both directions. Shouldn't we feel this massive weight on us? | It's pressure, not weight. It's not a directed force, it's force on every surface. The air pushing in from above has the same force as the one pushing from below, same for left and right, etc. And yes, we *are* being constantly squished together by air pressure. That pressure is even necessary for life. Water is only liquid at room temperature because the pressure squishes it together, preventing it from boiling. | So water would boil in space? | Related |
7 | ELI5: Air weighs 14 pounds per square inch, yet we don't feel it crushing us. The notion that internal pressure somehow acts as a counterbalance just seems to mean that we're being crushed in both directions. Shouldn't we feel this massive weight on us? | Do not confuse weight and pressure. When you hold a piece of paper horizontally, it feels the same pressure on both sides, so it balances out and all that you feel is the weight of the paper itself. Your body is mostly water, so it does not compress but when you free dive in water, as the pressure increases, the air pressure in your lungs does not increase so the water actually compresses your lungs. Then you will definitely feel the pressure. | Thank you. I was stuck at air weighing 14 lb. I'm like, almost three 5 lb bags of sugar in one square inch? | Related |
8 | ELI5: What difference does the vocal cords of a person who can sing have in comparison to someone who can't? | Absolutely nothing. The vocal chords are an instrument, the same as a trumpet or clarinet. Anyone is capable of singing well, the difference between someone who is good and who is bad is practice, technique, and for some, proper training. There have been studies proving that anyone can be taught to sing despite the fact that they have any practice in singing or not. | Is there any biological differences in someone’s singing ability when it comes to how well they can hear the true pitch that they are putting out? Not vocal chord related obviously, but the idea that anyone can kind of baffles me. I mean my friend. Asking for a friend. | Related |
9 | ELI5: How do phones listen for the voice command ‘hey Siri/Google’ constantly and not run out of battery? | On an iPhone at least inside the A series CPUs is a coprocessor that is always running, ultra low power and basically runs a deep neural net looking for the "Hey, Siri" phrase along with a few other things (motion data is the other big one). This coprocessor is extremely specialized, extremely simple, and uses next to no power because of that. Once it thinks it has heard "Hey, Siri" it sends a message to fire up the main CPU and process the rest of the message. There's [a really good paper](https://machinelearning.apple.com/research/hey-siri) that Apple wrote about how the deep neural net distinguishes the sounds if you want to go deeper. | It just occurred to me that this is one of those cases where the neural network basically matches almost exactly how our unconscious picks out our name, even when we're half asleep. Is anyone able to confirm that's what happens with humans too? | Related |
10 | ELI5: How are paparazzi constantly swarming around celebrities not considered harassment? | It’s a symbiotic relationship. The celebrities are like the host, but without the parasitic paparazzi they wouldn’t be celebrities | They get paid for their work. Why would they need to be celebrities? Money is great, but fame isn't really all that much fun. | Related |
11 | ELI5: how do astronauts do laundry in space? | I read the autobiography of Scott Kelly, who spent a year in space. They wear their clothing until it is too smelly to continue to wear. Clothing doesn't get as dirty in space because they don't sweat as much (except when exercising) and clothing usually doesn't rest against the skin as it does on earth, because they're just floating. Scott Kelly talked about how he was testing how long he can wear an article of clothing until it's too dirty to continue to wear. Once some clothing has been deemed too dirty, it's put in the trash, and all of the trash is sent back out to burn up in the atmosphere. | Did it say in the autobiography if they take up wet-naps to do a wipe-down bath? Because that's always what I envisioned they do. | Related |
12 | ELI5 Why is Pluto not a planet? | Because Pluto is too small and there are several other similarly sized objects (like Eris and Ceres) that are not elevated to "Planet" so a new group was created to describe these small but significant objects in Solar orbit. | Ok, IF I grant you the premise that Pluto isn't a planet, what is this new group called? | Slightly Related |
13 | ELI5: How do ancient ruins and sites get buried under so much soil? | It's basically a function of time, Lots and lots of time. With erosion, and deposition, and natural growth processes. There's dust/dirt in the air which gets slowly deposited and over eons of time builds up. There's shifting sands and erosion, which also deposits, sediments in areas. There's organic plant growth that slowly deposits fallen plants, leaves & etc which bury surrounding materials. There's also rebuilding over old ruins. ancient people didn't generally dig deep into the ground to construct another shelter, they just built on the ground, which could have the dirt covered remains of old structures buried in it. Think of the way even modern things get hidden over relatively short periods. An example is my brother finding a brick walkway in his yard that had been there probably less than 80 years but was buried under turf just by grass growing and covering it. Now think of how that would get buried over a period of a thousand or thousands of years. | So is the radius of the Earth just always growing as time goes on, or are things sinking towards the center of the planet as this happens? | Strongly Related |
14 | ELI5: Our stomach acid can dissolve all types of food including food like cows stomach (tripe). How come our stomach acid is strong enough to dissolve tripe but not our own stomach tissue? | because the tripe isn't producing mucus to protect itself like how our stomach is producing mucus to protect itself. If our stomach didn't have that mucus (for example due to overuse of drugs like aspirin or ibuprofen or because of infection by bugs like H. pylori), the acid would eat through the wall of our own stomach and cause an ulcer. | Out of curiosity what is an "overuse" of aspirin. Are we talking chugging a bottle a day levels of overuse, or are we talking like a single pill a week for 4 years straight could do it? | Related |
15 | [ELI5] Why do phones require WiFi/service? | Sure, you can have a phone without conecting it to anything. You just won't be able to do anything online. But you can do anything offline - play games, take photos, etc. Or are you asking why you can't have a phone connected to the internet without connecting it to the internet...? | okay it makes sense to me now. it seems i mistook wifi and service for something that allows your phone to use apps? (idk either, i was just very confused). but now i understand that they actually give you a connection to the internet (which i thought was simply another term for a web browser - but now i know is an entire network of things related to communication and information of different devices [?]), so there’s no real ‘alternative’ as you’ve got to be connected to something to use it. i think this is correct? | Related |
16 | ELI5 Billionaires, how do they buy things? | > Take Jeff Bezos, his income in 2019 was 1.7 million (just income) I'd guess "income" just means salary. > The scale of the recent sales -- including $2 billion in 2017 and $2.8 billion in 2019 https://fortune.com/2020/02/05/jeff-bezos-amazon-stock-net-worth-2/ Add $10 billion sold in 2020, and $5 billion so far in 2021, and he's got *lots* of cash to spend. For instance, he's spending about $1 billion per year on Blue Origin. | This sales would be taxed as capital gains right? When media throws around things like "Bezos only pays 0.5% tax" is that 0.5 of his total net worth? | Related |
17 | ELI5: Why do we have an internal monologue and how does it work? | From what I've read it's believed that some people have a connection between their frontal lobe where conscious thought is processed and their auditory processing center where speech is processed and constructed. Not everyone has this link however. About 25% of people don't and have no internal monologue. About 25% of people conduct this internal monologue all the time, and the rest only do part of the time. https://www.psychologytoday.com/us/blog/pristine-inner-experience/201110/not-everyone-conducts-inner-speech I have no such thing going on in my head. | This is such a strange concept to me. How do you think without words? My inner monologue like never stops. | Related |
18 | ELI5: how is an atom split? | It's a chain reaction. You take a few heavy atoms with large, unstable nuclei, and you spray some fast moving neutrons. One of them will randomly hit a random one of the atoms, causing its nucleus to break, which will release even more fast moving neutrons that can collide with other atoms and so on. The rate of the fission can be controlled, if you want it faster you inject more neutrons, if you want it slower you put something like heavy water to damp and slow down the neutrons | How do you spray them if they are so small? | Strongly Related |
19 | ELI5: How can Accutane/Isotretinoin stunt growth? | Accutane can rarely interfere with the growth of your long bones, such as the bones in your legs and arms, by closng the growth plate too early. | How does this work? What do you mean „rarely“? Some people get affected and others don’t? Some people stop growing and others just keep growing the same as if they never took accutane? | Strongly Related |
20 | ELI5: Why airplane flaps stay retracted during flight? | The flaps help make **more** lift, a wing with no flaps will still generate some lift. This is necessary for the plane to be a able to fly when it's going slow (i.e. take off and landing). Once the plane picks up speed the wings without flaps out produce enough lift to keep the plane up, so the flaps are retracted because they're not needed anymore, and they incure drag and aren't efficient lifting devices (at high speed) | Would you be able to expand on why they need to be actively retracted, rather than just leaving them out after take-off? | Strongly Related |
21 | ELI5:why there is no massive fake coin forging? | It’s slightly harder to forge a real coin than you think, and the costs involved make it expensive to do, so you’re not going to make very much money out of it. | One coin, yes. But that's a stable income for years without having to do anything after creating a forging station, no? | Strongly Related |
22 | ELI5: How has space dust (oversimplified) formed both planets as well as dust clouds? | For a dust cloud to collapse it needs to have a certain density. If dust is spread out too much the gravity is too weak to pull it together. (It's weaker than the kinetic energy of the dust particles). Compare this to a planet orbiting. It doesn't fall into the star because gravity and it's centrifugal force cancel each other out. But at a certain point there is a runaway condition, it gets together a little, wich increases density and gravity becomes stronger causing this effect to quickly escalate. At that point a star system forms. | Could you theoretically throw a big rock into a dust cloud and eventually have the gravity of the rock pull in the dust? Or is the dust cloud simply too spread out to be affected by gravity on the scale needed to produce any effects? | Strongly Related |
23 | ELI5: If Hawking radiation were to be true, how can black holes lose mass if not even light can escape it? | Under the model that permits Hawking Radiation, empty space isn't really empty. Pairs of particles and anti-particles are occasionally produced out of "nothing" thanks to quantum weirdness, and then almost-immediately annihilate each other. The net effect on the rest of the universe is thus, usually, nothing. Now imagine that this happens *riiiight* next to the event horizon of a black hole. If one member of the pair is trapped behind the event horizon and the other member isn't, they can't immediately annihilate each other like they normally would. Instead, the one that *isn't* trapped has managed to graduate to "real" existence - and, because There Ain't No Such Thing As A Free Lunch, the black hole's mass decreases by the same amount. It doesn't *technically* take anything from *beyond* the event horizon, but the net result is the same *as though* it had. | So matter is randomly just boom into existence, and the two particles just kill eachother. Why though, what’s the point and wdym by “real existence”, are the previous particles not real until that would happen? | Related |
24 | ELI5: Why can't they make CPUs bigger if heat dissipation is a problem? | Say you increase the size by a factor of 2 in both dimensions. That would result in quadruple the distance between two components - and while electrons do travel with very high speeds (not quite light speed, but close, relatively speaking) with the amount of electrons being moved you'd have a much slower CPU in the end. That's why the actual transistors are getting smaller and smaller - so you can pack them more densely and reduce the distance between them, to make faster CPUs. | You’re kinda right, but actually almost entirely wrong about the underlying physics and your conclusion about distance unfortunately. I don’t say this to be mean; you were simply lied to in school, Cuz they teach it that way to make it easier for kids to understand the basics. It’s not so much the distance/ resistance of the silicon or wires that matters; it’s more about how the gate size of smaller transistors uses a smaller current, and therefore uses less energy. So if you can get smaller and smaller transistors onto the same amount of silicon, you have more transistors to do operations with and each trans. Uses less electrical energy. Lower current with the same voltage is overal less electrical work, and is therefore also less heat created/dissipated. The distance between transistors is almost irrelevant In terms of electrical energy and heat. > and while electrons do travel with very high speeds (not quite light speed, but close, relatively speaking) with the amount of electrons being moved you'd have a much slower CPU in the end. This statement is actually completely wrong; not to be mean, this is exactly the conclusion a reasonable person makes when you’re taught about electricity in grade school. But it’s wrong. To be nit picky; electrons do not move at the speed of light ( or close to it) in a wire. I’m fact they don’t really do that outside of a wire either unless under very particular and somewhat rare circumstances. It takes a lot of energy to accelerate an electron to near speed of light speeds; that’s one reason why the large hadron collider is so huge. Electrons actually move pretty slow. What’s actually happening is all the electrons in the wire are bumping into each other; like a long conga line playing telephone. “[The Speed of Electrons in Copper](https://www.informit.com/articles/article.aspx?p=2916283&seqNum=4): How fast do signals travel down a transmission line? **If it is often erroneously believed that the speed of a signal down a transmission line depends on the speed of the electrons in the wire**. With this false intuition, we might imagine that reducing the resistance of the interconnect will increase the speed of a signal. In fact, **the speed of the electrons in a typical copper wire is actually about 10 billion times slower than the speed of the signal**.” “With this simple analysis, *we see that the speed of an electron in a wire is incredibly slow compared to the speed of light in air*. **The speed of an electron in a wire really has virtually nothing to do with the speed of a signal**. Likewise, as we will see, the resistance of the wire has only a very small, almost irrelevant effect on the speed of a signal in a transmission line. It is only in extreme cases that the resistance of an interconnect affects the signal speed—and even then the effect is only very slight. We must recalibrate our intuition from the erroneous notion that lower resistance will mean faster signals. But how do we reconcile the speed of a signal with the incredibly slow speed of the electrons in a wire? How does the signal get from one end of the wire to the other in a much shorter amount of time than it takes an electron to get from one end to the other? **The answer lies in the interactions between the electrons**.” And to be even more not picky; the actual electrons themselves nor their electrical potential energy are not what is supplying electrical energy to the circuit; it is actually the electric field created by the battery/wiring connecting the components in a circuit. The full explanation however involves the Poynting vector, and some base college level calculus so I’ll just leave the explanation in this video that does a great job explaining this concept without challenging math. [The Big Misconception About Electricity:The misconception is that electrons carry potential energy around a complete conducting loop, transferring their energy to the load](https://m.youtube.com/watch?v=bHIhgxav9LY&feature=youtu.be) Edit; thanks for the downvote(s), Grateful I was given 0 feedback to explain the downvote or why I’m wrong on any count. | Strongly Related |
25 | ELI5: Who Marion Millar is, and what was it she did that was so controversial? | She's a TERF who allegedy made threatening and abuses posts towards a few people, including a police officer on Twitter. She is a vocal opponent to a Trans Self-Identification bull, which would make it easier for trans people to be recorded as the correct gender. | What's a TERF? What are examples of her tweets? | Strongly Related |
26 | Eli5, Why are we so terrified of higher levels (~500PPM) of CO2 in the atmosphere? | If you're only interested in *air quality...* Sure, humans could potentially survive in 5,000ppm CO2, but there would be pretty profound physiological and cognitive impacts to that long-term. Around 1,000ppm is where harms to health begin, and exposure to 30,000 and above is generally only allowed for short intervals. In EL5: Carbon dioxide builds up in blood as a byproduct of your body and cells working. This "waste" from your cells actually turns your blood acidic and the gas needs to be removed before it begins to damage fragile organs, which is done in your lungs every time your breathe. Your lungs *really* like to exchange CO2 between your blood and the air, which is usually a good thing when you have a lot of carbon dioxide in your blood and little in the air. However, as the air you inhale becomes more saturated with CO2, your lungs will actually work "backwards" to move carbon dioxide from the *air into your blood.* This likely comes down to the fact that human lungs have evolved to expect atmospheric CO2 at <500ppm concentrations, so its never been an evolutionary advantage to figure out how to do that. Plants, by contrast, use atmospheric carbon as a sort of "fuel" during photosynthesis - not producing it as waste - so have no such issue with a buildup of concentration. | In terms of the cognitive impact, that would be the result of decreased blood flow to the brain? Would an increase in oxygen counteract this? Do we have any way of estimating how long it would take for humans to adapt to higher PPM? | Strongly Related |
27 | ELI5: Why do you feel nauseous when overly hungry, which can prevent you from wanting to eat? | There’s acid in your stomach that helps break down food. The amount of acid builds up if you haven’t eaten in a while. It’s this excess acid that causes nausea. | But why does it prevent you from eating? | Strongly Related |
28 | ELI5: Why does music- and sound in general- sound lower in pitch when it’s slowed down? | Sound is produced by vibrations. How fast these vibrations are determines the pitch of the sound. Slower vibrations produce lower pitched sounds, whereas faster vibrations produce higher pitched sounds. For example, let's imagine a guitar string. A guitar string that vibrates 1000 times a second when it is plucked will produce a higher pitched note than one that vibrates 800 times a second. When you slow a recording down, you are essentially spacing those vibrations out over a longer period of time. This results in less vibrations per second than the original which drops the pitch of the whole recording down. | Why exactly do slow vibrations produce a lower pitch sound though? Is that just the way our brain perceives it, in the same way color is just the way our brain perceives different waves of light? | Strongly Related |
29 | ELI5: Why is South Africa so prominent compared to other African countries? | South Africa is unique because : 1) We were not Colonised initially. We were a waystation for boats of the Dutch East India Co. Nothing more. That settlement became bigger and bigger as Europeans from various countries saw the opportunity to create a new lofe here in Africa. 2) The expansion or Colonization of South Africa was due to a breakdown between those who saw themselves as "Boere" or "Afrikaners" ( Meaning second or third generation immigrants) and the ruler of the what had by then become the Cape Colony. The Boers set out north to find fame and fortune but in the process creates many small wars with the indigenous peoples. 3) Eventually, After a series of small wars and a couple of big ones between everybody, The union of South Africa was created. A South African government under British rule. 4) South Africa is prominent because of our violence. The violence of Apartheid where people protesting for equal rights were shot in cold blood and the violence that stood up against it. Also, the violence of our current time which is extremely high because it mostly senseless unlike Nigeria which has Boko Haram etc. 5) We are extremely mineral rich. We have a shit ton of gold, platinum and diamonds along with amazing natural wonders and wild life. Where in other colonised countries such as DRC, the indigenous people were massacred for their resources, our people were strippes of their rights and often "forced" through circumstance to mine these resources. 6) We are prominent because we had nuclear weapons but dismantled them, we have won the Rugny world cup three times( suck it eddie jones), we have one unique biome that is only found here, we have Africa's only Biosafety 4 lab, we have one of the strongest militaries in Africa along with a stable economy(in the past). Source: I am A South African and I studied our history. Feel free to ask questions. | I heard china is heavily investing in certain countries to the north, is anything happening south? | Strongly Related |
30 | eli5: What is the actual continent name for Australia? | Australasia and Oceania are regional names, and are dissociated from the name of the continent. The proper name for the continent is Australia, although it has other names (e.g. Sahul, Austalinea) for when it becomes important to distinguish between the continent and the country that dominates much of that continent. | So which continent is New Zealand on? | Related |
31 | ELI5: How does the internet work? | So imagine you and your friends all connect your computers together using Ethernet cables, this idea catches on and more and more people connect till everybody is connected to your network This is a very simplified version keep in mind | But how does the data travel without wires ? It flies through the air? | Slightly Related |
32 | ELI5: How is it that we can feel people staring at us? Or is it an illusion of the mind? | It's an illusion. It's been [studied](https://www.sciencealert.com/the-science-behind-why-you-think-you-re-being-watched), and there's no evidence that people can tell without looking. Part of it is we've evolved to observe people's eyes, so it's easier for us to notice when those eyes are directed at us. Also, turning to look at someone often makes them look at you. | And there's a bit of a bias too. If you think someone's watching you and check and they are, you'll remember that. But if you think someone's watching and it turns out no one is? You won't remember that because its not important. so it can seem like its more accurate than it is. | Slightly Related |
33 | Eli5: what do spiders eat in bathrooms? Do they starve if nothing falls in their web? | They’ll eventually ditch the web and try again elsewhere if there’s slim pickings in that spot. You’ll know if they’ve been successful because they don’t eat the exoskeletons and so pieces of bug armor begin to collect beneath active webs. They like humidity because the water helps keep the web material pulled tight. It’s harder to keep a web taught when it’s very dry. Some household bugs like silverfish are also attracted to moisture. | Damn, that means I really should be feeling sorry for the little guys - no exoskeletons ever there, when I clean the webs once in a while. I know it sounds crazy, but I like my spider buddies, can I give them some food somehow? | Slightly Related |
34 | ELI5: What does it mean when people say “Light behaves as a wave or as a particle”? Whats the difference between waves and particles? | Light is a wave. It has frequency, wavelength, it experiences interference like other waves, it diffracts. Light is also a particle. It has momentum, it moves in a straight line until forced to change, it bounces off things, it has physical interactions with other particles. So which is it? It's both. Turns out, particles and waves have more to do with each other than we once thought, but [explaining *that* requires a Ph.D. in Quatum Mechanics...](https://www.space.com/wave-or-particle-ask-a-spaceman.html) | Wouldn't it be more accurate to say light is neither a wave nor a particle, but it has properties of both? | Related |
35 | ELI5: What does it mean when people say “Light behaves as a wave or as a particle”? Whats the difference between waves and particles? | Imagine you've got a 1x1x1 cube. And you allow one photon of light into that cube. You would expect that photon to be one individual particle inside the cube. But when we do experiments, it's not, sometimes it's one individual particle, sometimes it's one individual wave. The delayed choice quantum eraser is the one experiment I *need* a solution for in my lifetime. | >The delayed choice quantum eraser Is there a link that could explain what this is about? Any similarities with the double slit experiment? | Related |
36 | ELI5: How does something wind up becoming muscle memory after some time? | There is a specific part of your brain (cerebellum) that does that specifically so you can take your higher mind off doing those things. | So walking for example? You don't think of how to walk and where you're stepping because you've been walking for so many years, right? | Related |
37 | ELI5: How can the spacesuits that our Apollo astronauts wore on the moon cost $670,000 in the 60s and 70s, and now cost $500,000,000? | directly from your article: NASA has been working on next-generation spacesuits, which act as mini spaceships that protect the astronauts from the vacuum of space, for 14 years, the IG said. In 2016, NASA decided to consolidate two spacesuit designs into a single program that it would oversee | Did the Apollo spacesuits not protect them from the vacuum of space? | Strongly Related |
38 | ELI5: Why are there gaps in mirrors? | Mirrors are a piece of flat glass with a polished aluminum backing, there’s no gap. The glass is transparent though, so the reflective surface will appear to be slightly behind the glass surface. The polished aluminum reflecting surface is too flimsy, delicate, and easily corroded to be used by itself, it needs the glass for protection and structure. | Don't have some also mercury in them or something? | Related |
39 | ELI5: How does "fattening up" an animal result in more usable meat? | It is easier for a body to build muscles when there is a calorie surplus. Proteins in the diet are necessary to build muscle, but will be used for energy if there are not sufficient energy from fat or carbs. | Is there any effect on the muscles in that the overall weight is higher so the muscles have to grow to support normal daily movement? | Related |
40 | ELI5: Why is malnutrition less efficient if you want to lose fat than eating properly? | Malnutrition will cause you to lose weight … but can also cause you to lose muscle, bone mass, hair , teeth, eyesight, brain function . Eating healthy and dieting you lose weight but gain muscle, healthy brain function and still provide minerals and vitamins for your body to still work normal | h-hair and teeth- I kind of lose a lot of hairs lately but i'm not balding, can I even go bald from this? | Related |
41 | ELI5: In stepup transformers, why the increase in voltage correspondingly increase the current? | It's an "everything else staying the same" scenario but you're mentally jumping to the next step. The better way to think about it is that the transformer has a constant amount of magnetic flux on both sides. We end up in a bind when we try a harness that flux. The same coil that cuts the lines of flux to create a voltage is also an inductor that will oppose changing current flow. As the coil gets longer, the voltage goes up but the current shrinks due to the extra impedance. | Your logic makes sense Now I figured the missing piece in my understanding, which is sekf induction. Could you please share your intuituve understanding of self induction? | Related |
42 | ELI5: What is a recurrence relation in context of algorithms ? | A recurrence relation is fundamentally a mathematical concept, so you're not going to fully understand it until you put some time in to think about the math. But here's an example of applying one. Suppose you're cutting a piece of paper. Each time you cut the paper, you take all the pieces and stack them on top of each other, then cut right down the middle. Now we want a function for the number of pieces of paper produced by c cuts. Intuitively, we know we'll go from 1 to 2 to 4 to 8 to 16... pieces of paper. We can therefore jump right to an analytic function: f(c) =2\^(c-1). However, we can also write the recurrence relation. Each time we cut we double the number of pieces of paper we had before: r(c) = 2\*r(c-1) for c>0. We also need to specify that we started with 1 piece of paper: r(0)=1. Both ways of expressing the number of pieces of paper are valid and useful. For my money, the recurrence relation better expresses our intuition. Each cut produces twice as many pieces as the number we had before that cut. A computer is also very good at calculating the recurrence relation because it just means writing a simple function and calling it a bunch of times. This is not to say that a computer should have any trouble with 2\^(c-1), but there are plenty of recursive expressions that don't have an analytical equivalent (like the Fibonacci sequence), yet they're still easy for computers. This is one reason why recurrence relations are such a big part of algorithms. | Not OP, but thanks for the explanation. I'm just a little lost here, f(c)=2^(c-1) That would mean that for 3 cuts ("c"), f(c)=2^(3-1), which would be f(c)=2^2, correct? Hence, f(c)=4. Shouldn't the answer be 8 though? | Strongly Related |
43 | ELI5: how do dna testing companies calculate the percentages of your origin and how can they be so exact? | They just guess. The percentage figures are effectively meaningless but people love the impression of truth when they are spending money. | So it's a lie... shouldn't that be illegal? | Strongly Related |
44 | ELI5: When a movie has five different people listed as "Producer," what did they actually do? | Producers on a movie have a ton of different roles, some of which have distinguishing titles. Executive Producers are usually the ones who finance the film, while Line Producers manage the budget and can be responsible in part for hiring staff. The plain old ‘Producer’ title can refer to anyone who had a significant role in getting the movie made - for example, finding (or in some cases, writing or developing) the script, finding a writer to write a script for an idea they have or to adapt existing content like books, etc. they’ve optioned the rights to, attaching actors to roles (usually while they’re seeking funding) and securing financing for the movie, which could be via a production company or a studio. Things like that. In TV it’s a bit different, but I just kept it general to movies based on your post. Edit: clarification | So would I be right in saying that if a film is produced by someone I'm a fan of, it doesn't necessarily mean it will have the same style/quality? Unlike if it had the same director, for example. | Strongly Related |
45 | ELI5: How is the order of elements decided when talking about compounds? | Both are actually acceptable but usually its done by metals first(for inorganics) and then the heaviest element takes priority Ie AlBrClOH but i only really cover organic chem so i could be wrong Edit- turns out chem doesn’t work with my head when im half asleep, see other peoples answers | but then H2O would be wrong then, due to hydrogen being lighter? | Strongly Related |
46 | ELI5: Why is doing taxes so complicated in the US? | The IRS doesn’t know him much tax you owe. There are many rules and deductions that effect your tax rate. The IRS would have to have many times the people to track everyone’s tax situation. | That seems to be the common answer, that the IRS DOESN’T know, but then how are they able to tell when someone pays the wrong amount? | Strongly Related |
47 | ELI5: How can animals eat uncooked meat and nothing happens to them, but humans get sick from it? | Animals can't cook. Humans have discovered the use of fire and started cooking meat. At one point way way way back our human ancestors probably ate a lot of raw meat. We just can't stomach it as well now cause we adapted to cooked meats and goods. | i'm assuming it has a lot to do with what gut-bacteria we have. If this is true, if we started eating raw meats again, over a long period of time, would we be able to eat raw meats w/o many issues (parasites excluded)? | Strongly Related |
48 | ELI5: Why won't the Chinese government tell the ISPs to block certain websites to make VPNs useless against the internet censorship? | How about cutting every network outside of china and create a own network just inside china, like cutting every cable that goes outside china | then where would the hypocritical elites/authorities get their episodes of the office, friends, and seinfield? | Related |
49 | ELI5: Why would an apartment complex change ownership multiple times in a year? | Flippers operate on apartments as well. Sometimes a development company will buy the complex, renovate it, and then sell it to a more upscale management company. | Interesting. My whole city including the shitty areas are changing. The once shitty complexes are getting face lifts including mine. These properties that have come through where I live don't own any fancy places but they are fixing up the interiors. It's literally happening everywhere in my city. My current management has not allowed any tenants' renewals because they were renovating all units. So many apartments at my place are empty. They do give the option for tenants to transfer units without a transfer fee but also require 3x the rent instead of 2.5x like the previous ownership. Do you think this could be why? Like they aren't making enough profit? Things have been different ever since the mass evictions. I live in a rough patch, but ever since that, things are different. I actually like where I live now. I feel better. It is sad for those who got kicked out basically but most of them were aholes. I see a difference. | Strongly Related |
50 | ELI5: How are tumors formed? | Our bodies are made up of tiny cells, that constantly replicate themselves to upkeep your organs and tissues. Sometimes, during this replication, the DNA inside the cell mutates because it’s copied incorrectly, so the cell becomes different. Sometimes the mutation is benign and doesn’t do anything harmful, but sometimes, it turns the cell rogue, so it starts to replicate itself uncontrollably and form massive tumors. Cells usually have checkpoints in place to regulate how fast they divide, but cancer cells have mutated aspects of these checkpoints so that they no longer apply to them. | But what about those that have teeth and hair? | Strongly Related |
51 | eli5: What is Dielectric strength requirement? | Dielectric is basically another way of saying insulator, i.e. a substance that doesn't conduct electricity. Ferrite is a type of ceramic that isn't electrically conductive but it is magnetic. So dielectric strength is the question is how good an insulator the material is. The way that's tested is putting a voltage across the material, and increasing that voltage until the material breaks down and the thing starts to conduct. Whatever voltage that takes, you then divide by the thickness of the material, and you get a dielectric strength value of a voltage per millimeter. | Thanks for replying. What does dielectric strength of 2kv mean? | Strongly Related |
52 | ELI5: Are gas giant planets gassy? As in could I land on a gas giant and like poke my finger through? | The structure of gas giants isn't well understood yet and likely won't be until we can send probes into the atmosphere. It's very likely that under the atmospheric layer lies a comparatively thin ocean of liquid helium and trace amounts of other liquids. This ocean will be contantly boiling off as more liquified gases rain down from above. Under the ocean lies a huge rocky planet structure far larger than the inner planets. This rocky core will have a very thin crust that will be contantly broken apart, melted and reformed by the huge amouts of nuclear decay in the core and by the tidal heating of the orbiting moons. Despite the fact that there's an ocean of liquid helium sitting on top, the planet's core is generating so much heat that the crust can't remain solid. This core heat is what's boiling the oceans and causing the incredible storms in the planet's atmosphere, such as the famous giant red spot on Jupiter. | Why is the core so hot? | Strongly Related |
53 | ELI5: What exactly are neurotransmitters and why do we need so many different types of neurotransmitters? | Neurotransmitters in short are little chemicals that our body responds to in various ways (transmitters). We add neuro because they originate and communicate across neurons. We have a number of different neurotransmitters based on a few reasons, what is the likely the most important reason is to send different signals to the same tissues or similar tissues; as well as to reduce “noise” from neurotransmitters escaping and activating nearby cells and neurons. | Are dopamine and adrenaline neurotransmitters? | Related |
54 | ELI5: What, exactly, is the legal status of Taiwan? | If Taiwan declares independence it could provoke a war with China. Taiwan would lose this war and lose its independence. The status quo is that Taiwan gets to be treated as an independent state and have unofficial relations with most of the world for as long as China believes there can be a peaceful solution to reunification. | Even if it takes 500 years? | Related |
55 | ELI5: Hard to swallow pills sometimes but not food? | Because you don't "chew" the pill. When you chew, your saliva makes the Bolus (chewed-up food) slightly wet, so it slips through the Esophagus. like when you drink water with the pill. it's easier than crying in the corner. | How does one pronounce this word Bolus? | Related |
56 | ELI5: What was the reason and significance of medieval monks having part of their head shaved on the top? | Tonsure. That is what being called tonsured was/is, it represents initiation, the ceremonial step of shaving heads (or taking the veil if fem gen) as taking on religious vows/habits. | So it was the male version of a habit? | Strongly Related |
57 | ELI5 How are airplanes able to provide Wifi/Internet, but my phone can’t? | Airplanes have communications antennas to communicate with air traffic control, GPS, etc. that can include satellite internet connections. | Don’t they still tell you to put your device in airplane mode? I haven’t flown for a couple of years but rarely was there internet available. | Slightly Related |
58 | ELI5: Why is it free to use a GPS signal? | Basically because the US agreed the benefits for everyone to use it for free outweighed the pain of trying to keep it a secret/something only US military could use. And there was a significant disaster too. So back in the 70s, the US military came up with a very accurate way of knowing where they were at all times. If you have 3 satellites overhead in space and they all were broadcasting a time synchronized signal, you could triangulate your position very accurately. Like within a few meters. Very handy for flying planes and dropping bombs very accurately. So they launched a bunch of satellites up there and everything was great. At the time only the military could access / decode the signals. Then, a Korean airliner (which did NOT have GPS obviously) flew into Russian airspace and the Russians shot it down (they weren't very friendly back then and it didn't help that the Korean pilots couldn't communicate very well) thinking it was an American spy plane which they were expecting at the time. Anyways, lots of people died. Realizing that that really sucked, and GPS totally could have prevented that from happening, President Reagan decided that everyone should have access to GPS signals. And voila, there you go. edit: sigh, top comment, headed for the front page and it gets deleted. FMK. | Can the US switch their signals off and screw everyone up? | Slightly Related |
59 | ELI5: How does have too many synapses lead to autism? | One of the process the human brain does is called synaptogenesis (sp) it’s happens over the first two years of life with the brain building connections and letting old connections die out. Well one theory is that that process doesn’t occur in autism. Think of a highway and it has 5 lanes that merge into 1 well what happens? Similar thinking and process at least that’s my rudimentary understanding. Spent lot of time after my sons diagnosis In neurological and psychology journals. | Can you more elaborate on your highway example and how it relates to autism? | Strongly Related |
60 | ELI5: Why is everything so unaffordable for this generation even though we work as much as our parents/grandparents did? | Some of it is wages like others are suggesting but that’s not the only reason. My grandparents weren’t eating out all the time, sucking down 5+ dollar coffees daily, energy drinks, paying for expensive cell phones and data plans with another internet bill at home. They didn’t spend hours a day shopping on Amazon or having door dash bring dinner that doubles the price, they weren’t paying for childcare and Netflix or cable even. They had a very basic set of bills every month and because of that they were able to pay cash for their land then keep saving till they could afford to build their house with out borrowed money, that saves all that interest that we pay for. I think most of us would be surprised at what we could afford if we skimmed down to the very bare essentials but we don’t want to, or at least I don’t, I like my Redbull and iPhone. | The extranuous expenses is part of it, but some of those are actually COL things now. Basic society does not have the same minimum requirements of 50-70 years ago. It would be nearly impossible to get a job today without a phone. Not even a smart phone, just a phone. Companies dont generally hire on the spot now, so you need to be contacted to be told you were selected. Thats on the given you went to a company, filled out an application since applying online is eliminated by no internet. (I acknowlege you could go to your local library to use their internet for application, and email notification, but unless you are going every day, you may miss the window of time a company expects you to respond). Childcare. This is correct, our grandparents did not usually pay for childcare. This is because their generation saw almost exclusively single-income families. And that single income was able to afford basic cost of living for a nuclear family, which by todays standards is somewhere in the 40-60k range. So with 1 parent as stay-at-home, childcare is negated. Also, a big reason for many people eating out/ordering is fatigue. If both parents worked 8-10 hours, then dealt with kids and errands, the motivation/willingness/time available to cook a meal is gone. Look at the (both exaggerated, and SUPER excessive gender role isolation) classic examples of family dynamics on things like Leave it to Beaver, Pleasantville, That 70's show; wife wakes up, cooks breakfast and lunch for husband and kids, husband goes to work and kids to school, wife cleans up and then free to do whatever for several hours, then watches kids when they return from school, and cooks dinner to have available when husband returns from work. Even adding a pre-school age child doesnt change this other than flipping "free to do whatever" into " take baby to park". The cost of childcare PER CHILD in many places is often over $150/week. At minimum wage, that is 20 hours of pay, or half the pay (before taxes) for that same week of work. Add a 2nd kid, and it is now less than breakeven to work rather than stay at home and watch the kids for anyone on minimum wage. As for the cake-batter-levels-of-sugar coffees and energy drinks, thats solid. They are an unneccesary expense. But i also like my red bulls so fuhh-Q. I agree with the basic sentiment, hell i would prefer to just go live off grid most days, but last time i tried my family reported me missing. Did you know the police will basically arrest you for being a missing person? At least in Boulder Wyoming they will. Guns out and everything. | Slightly Related |
61 | ELI5: If childbirth is so extremely painful - why aren't more methods of reducing (or completely removing) the pain used, like the methods used for surgeries? | They are. Have you never heard of a spinal block. The reason general anesthesia isn't used is it would also affect the baby. Also many women want natural childbirth without any drugs. | The question is mainly towards general anesthesia - never heard of spinal block tbh. Why would general anesthesia affect the baby? | Strongly Related |
62 | ELI5: When swimming pools are heated to 30°C and the outside room temperature is 25°C, why do we still think its freezing when we first go in the pool? | Well, we don't sense absolute temperature. What we sense is the transfer of energy/heat. When we are warmer than our surroundings, our heat leaves our body and that feels colder. When our surroundings are warmer than us, heat transfers to us and we feel warmer. Different materials have different capacities for heat, and also rates of transfer. Air can't hold as much heat energy, and it is also more of an insulator, so we hold on to our heat better. But water will transfer heat much better, so even though 30C water is warmer than 25C air, we are warmer than both of those, and water transfers it better. So we sense more energy leaving our body into the water, thus is feels colder. Same as feeling room temperature wood, or room temperature copper. The copper will feel colder because it sucks our heat away quicker and more effectively. | Ok follow-up question. What is it about water or other materials that dictates how quickly it transfers heat? | Strongly Related |
63 | ELI5: Why can't Tesla sell their cars directly to consumers in Texas? | Most states passed laws requiring car companies to sell through dealers licensed by the state. This creates local business opportunities and greatly simplifies making state regulations stick. Otherwise the Interstate Commerce clause of the US constitution would allow federal laws to overrule state ones. Tesla doesn't like it, for all those reasons plus they don't like to share profits with anyone. | Isn't that just making the consumer pay for a pointless middle man that adds no value? | Strongly Related |
64 | ELI5: Why is every staple crop around the world some kind of starch (wheat, rice, potatoes, maize, ect..)? | Starch is a complex carbohydrate which means that it is broken down into sugar by the body. So it's a source of energy. That's what makes these staple crops, they are grown because they are an efficient source of food energy. | They're kinda "quick-burning" sugars too, right? It's been a while since I studied; I just remember something about excess starch stuff quickly converting to fats if not used up . | Related |
65 | ELI5: How does a dome shape influence the heat retention and "heating evenness" of a brick oven? | The bricks are designed to absorb heat they can then emit back into the cavity. The dome is centred on the middle of the oven (I presume) where the pizza would be. This means that heat either reflected or emitted from the bricks would always generally point to that spot. | This is interesting but I think my sticking point is what "reflected" heat means. I thought there was conduction and convention as means of heating. I'm learning now that thermal radiation is a form of electromagnetic radiation that causes heating. It sounds like that's what we're talking about here (i.e. not the movement of energized air particles, but the radiation of photons at food-cooking frequencies). Is it fair to say that that's a significant part of the cooking story here? | Strongly Related |
66 | ELI5: If a planet-sized mirror facing back at Earth suddenly appeared a million light years away, what would we see on Earth? | Nothing much, that's far too far away for us to get a particularly good view in the visible spectrum especially of earth. As an example, here's one of very few photos of exoplanets, in this case only 300 lightyears away: https://earthsky.org/upl/2020/07/TYC-8998-760-1-two-giant-planets-VLT-800x800.jpg . Big thing at the top left is a star, the other two dots are very large planets. If we had magical telescopes that could see that far in detail, without having to worry about any degradation over millions of lightyear as light passes through the odd dust, gas cloud, etc? And if it was perfectly aligned with where your telescope was? We'd see Earth as it existed 2 million years ago. Or more specifically, whatever happened to be at the exact location of your telescope 2 million years ago - which if it was on Earth, would likely mean you're just looking at an empty area of space, as Earth's position around the sun wouldn't match up with its position precisely 2 million years ago - that's not even accounting for the fact that the solar system is moving through the galaxy, the galaxy is moving through the universe, and space is expanding. | if the mirror just suddenly appeared, wouldn't we see nothing for 1 million years and then start seeing a 2 million-year-old image? | Strongly Related |
67 | ELI5: Why do humans go through puberty and aren't born post-pubescent? | Yes animals go through a form of puberty but ours probably seems more accentuated or unique due to our much more sophisticated and complicated social structure. But yes, to a good extent our offspring can only develop, grow and mature so far within the confines of a grown adult. Despite one instance of a four year old getting pregnant and having a child at age five, generally there’s a far higher survival rate for child and mother if they grow and mature to be capable of reproducing later while the child survival rate is also greater with parents who are older and more capable. So it’s all a case that the full development can’t take place completely within the womb and continues outside it until puberty when the body recognises it’s ready to have and care for children and goes into a rapid development and change phase to prepare for that. | Follow-up: why can't a baby start going through puberty from birth? What prevents the body from recognising it's ready to reproduce? Thank you very much for the answer, it was an insightful read. | Strongly Related |
68 | ELI5: How does trace amounts of fetanyl kill drug users but fetanyl is regularly used as a pain medication in hospitals? | So speaking from some experience, an old friend used to stomp his heroin with fentanyl purchased as a "research drug" from China and shipped to a drop house. He was 100% an addict and the reason he was cutting was he was taking his "pure" heroin he received, holding a large percentage back for his own use, and selling the stomped on product as "pure." Problem was his supplier had the same ideas and used **carfentanil** to cut it before passing it down to be sold. My friend does his usual and shoots up a hero dose and the rest is in the obituary. [Picture](https://imgur.com/a/drk74iJ) reference for how small of an amount of these synthetic opioids is considered a lethal dose. **Edit:** Because jesus, didn't expect this to blow up. To clarify, friend in question was my half brother, who unfortunately got me on drugs in the first place. I've personally been clean since 92. He started off slinging pot for the mexican mafia back in the late 70's and branched off to coke and speed in the 80's. The wake up call (for me) was when he got shot in the head during a bad deal and managed to live. (The bullet skidded off his skull and bounced around in his sinus cavity before exiting by his eye.) I'd like to say he turned his life around at that point, but he didn't. We fell out after he started using what he was supposed to sell. (Found this out when people showed up at my moms house and held a gun to her during a family dinner.) He pops up every 5-6 years "clean" and we catch-up just for him to disappear again. Last time he popped up around 2013 was when he tried to recruit me into his scheme and basically laid it all out. He was dead within the year. Edit#2: As mentioned his H was white, he didn't sling black tar or that brown shit from the middle east, his words; "My shits pure, I get it from the Asians." | What does stomping mean in that context? | Related |
69 | ELI5: Why is it hard to swallow food u don't like? | Because the reason your body makes you dislike a food is because it thinks it's poisonous. Your body has a vested interest in you not eating it, so it makes it as hard as possible for you to do so. | Ok, but why does your body think it poisonous when carrots are overall healthy and don't have a negative effect on ur body? Is it just not used to it? | Strongly Related |
70 | ELI5: What exactly is happening in a muscle when it fails a rep? | Not sure I fully understand the question. If you mean why muscles tire after lifting heavy weights, it's because of lactic acid buildup. Muscles produce intense energy in short bursts through an anaerobic process that burns glycogen and doesn't require oxygen. The tradeoff is that it cannot be sustained for long periods of time and the muscle is overwhelmed by lactic acid. On the other hand, aerobic exercise allows muscles to produce energy using oxygen, which can be sustained for far longer periods of time before reaching exhaustion. That's what happens when you run long distances. | So is exhaustion a direct effect of lactic acid build up? | Strongly Related |
71 | (Eli5) Howcome radioactivity and DNA mutations are only bad? | They're not. This is natural selection. Genetic mutations that are favorable for your body, and environment, are passed on and your species survives longer. Bad mutations equal cancer, disease. Good ones equal better survivability long term. It's hard to understand, but going meta, the fact that we aren't covered in hair still is a huge mutation that turned positive for homo sapien sapiens. | But when you are exposed to something that alters your DNA, can it be positive? | Strongly Related |
72 | ELI5: what gives water shadow ? | Are you asking why water *casts* a shadow? Like on the bottom of a pool and such? Those aren't shadows in the traditional sense of light being *blocked* by something. Instead, water causes refraction.....when light hits water it slows down, this slow down changes the direction light is traveling. In the case of a pool, the surface often has some waves to it...even if they're really tiny waves and it looks completely still it's likely still moving to some degree. This movement causes light to constantly be drawn in different directions as it passes through the surface of the water. This constantly changing direction of light acts almost like a disco ball, causing high and low amounts of light to hit different parts of the floor at the same time, which causes dark and light spots to appear, creating "shadows". ELI5: Water rarely sits still and is always telling the light to go a different way. The light does what it's told which causes bright and dark spots to appear. | Wow. So something which totally reflects, like a mirror, should have a complete dark shadow and something which only refracts like a glass should have no shadow at all! Also, does diffraction have anything to do with the variable spots of brightness? Moreover, I am thinking if the irregular shadow spots formed at the bottom of a water body are in any way used by the marine animals to like detect approaching objects | Strongly Related |
73 | ELI5: How can foods like corn have any nutritional value to humans if we can't digest it fully? | Key word here is “delicious.” And grilled corn on the cob with butter and a little salt and pepper is delicious. I like smoked paprika as well. | Read the same thing 4 times in a row until I came to this. I'd say this answer is what the OP is looking for. Can we get this question marked as answered now? | Strongly Related |
74 | ELI5: Why can't the US make immigration easier for immigrants to reduce illegal crossing and stop holding the bag for all of the immigrants they capture? | If you made it legal to take things that aren't yours, theft would be nearly eliminated! You can't just legalize something to make the problem go away. | I'm not saying open the border. Just make the process easier to come legally. Why are people so polarized on this issue that its open borders or close them completely? There has to be a middle ground. | Strongly Related |
75 | ELI5: if a world war is a conflict consisting of multiple important/influential nations, how is it possible there were only two? | It was difficult to understand your question but now I do. World wars are defined as a global war involving the multiple influential nations all engaged in a black and white fight. They’re very rare because the type of conflicts or events that trigger a world war require very specific rules. In order for a world war to occur, all influential nations must be able to fight. They must have the economy to support the financial needs of warfare and they must have a viable army to sustain the large combat. Alongside this, all the nations involved must have a clear and non-ambiguous reason to fight for. For World War 1 it was in retaliation to an assassination and World War 2 it was against nazis. World War 1 was a special case. It’s what would most likely happen today. If 2 majorly influential countries went to war it triggers a world war automatically because of the complex network of alliances that all countries have. If US is attacked, the UK will aid the US. This will trigger all of NATO. This will then trigger most of Europe and also India. If the country that attacked the US is China, then Pakistan will join, which brings a good portion of Middle East into the warfare as-well, and if Ukraine is involved, by default, Russia will be sucked into the warfare too. Most countries, if not all, understand this. So they fight from their desks through economical sanctions or by giving guns to terrorist groups who either blow up buildings in the other country or fight the terrorist groups backed by the other country - otherwise known as “proxy wars”. | So is it realistically possible to attack any other influential country without starting a world war now? | Strongly Related |
76 | ELI5: if a world war is a conflict consisting of multiple important/influential nations, how is it possible there were only two? | I would contest that definition of a world war. The two world wars literally had battles all over the world. The second one much more so. | So would a world war more closely mean a war in which countries from each continents/larger regions are in conflict? | Strongly Related |
77 | ELI5: Which quality of sound makes it trivial for us (even with our eyes closed) to differentiate between a person who is speaking from far away vs a person speaking next to us in a faint voice i.e. what does a brain read in a sound signal to analyze distance from source ? | Because, evolutionarily speaking, that was a distinction you needed to be very good at making. We're social apes who do a ton of stuff by voice, so being able to pinpoint exactly where a voice is coming from is highly necessary. | that’s true. Which properties of sound do we use for this spatial deduction ? | Strongly Related |
78 | ELI5: why can hunger either go away or be briefly managed by food just touching your tongue. Shouldn't it have to be in the stomach first or digested? | Since it being on your tongue usually precedes it being in your stomach, and since you want to have senses in your tongue anyway (so you don't eat something you shouldn't), and since your stomach is a pit of acid that needs a thick membrane to prevent that acid from digesting your insides, it makes sense then, that your mouth is a primary means of managing hunger. That said, the emptiness/fullness of your stomach does play a role in being hungry. But if there is food on your tongue, it's safe to assume you are taking care of that whole hunger thing, so no sense it continuing to ring that hunger alarm, is there? | Does that mean hunger can perpetually be staved off by putting food in the mouth but not eating, if one was so inclined? | Strongly Related |
79 | ELI5: What are electromagnetic fields, plasma, and how are gravity, electricity, and magnets related? | Electromagnetic field: the potential around an electric charge (electric field) or a magnetization (magnetic field). They are different manifestations of the same force - electromagnetism. A changing electric field creates a magnetic field. A changing magnetic field generates an electric field. Plasma: gas that has been stripped of outer electrons - typically done by making it hot or by funny a current through it - and now has an electric charge. Gravity, electricity, and magnets: gravity isn't related to either, as we currently understand it. Electrons have a magnetic field, which forms loop-like curves in one end and out the other. When these loops line up between a large number of electrons, the fields add and become stronger. Electricity is elections that move through conductive materials, bouncing from one atom to the next. As stated earlier, moving/changing electric fields create magnetic fields and vice versa. | So what if you have a magnet. I suppose this means that the magnet possesses a constant electric charge? There's plasma which is in our blood, plasma TVs, and plasma in the universe, such as that shot out of the sun. I'm sorry if this question is silly but I'm assuming all three are different? Can you elaborate on the looplike curvse that electrons create? | Related |
80 | ELI5: How many pieces of hardware does my internet traffic pass through? | There's a lot of hardware that you'll pass through, and most of it you have no way of even knowing. You can only find out *approximately* how many routers your packet touches on the way to its destination because of a fancy hack of setting the TTL to various incrementing values(which decrements with each router until it reaches 0 to prevent routing loops), and getting TTL Expiry messages back from the router that sent them. However, that doesn't even tell you the number of routers, since technologies like MPLS let a service provider create a pseudo-routing-shortcut through their network from one edge to another, which can bypass the TTL mechanism in the intermediary steps. Then you have various switches and signal boosters along the way, which are also going to be transparent. At the same time, you could be going through "virtual" devices. You could have a packet go into a Layer 3 Switch on one Virtual LAN (VLAN), which passes between two Layer 3 Routers within the switch, and then out another VLAN on the switch. Topologically, this could have been 4 devices, but it's actually just one. | Yeah, to piggyback onto this comment, if you run a traceroute from your laptop to somewhere on the internet, first hop will be the router in your house, second will the the gateway given to your router via DHCP. In your house, you may have an all-in-one modem/router/wifi. You may have the modem separate. You may have the WiFi separate. So we're at 1-3 devices before you leave the house. Then the next hop is a device in some sort of Central Office the ISP has set up, probably somewhere in the closest city area. But it's not a single wire, there are going to be various switches/hubs/etc. How many? Probably somewhere in the neighborhood of 2-10? (my "last mile" knowledge of landline networks isn't the strongest). So we're at a range of 3-13 devices before you even hit the second hop of a traceroute. | Slightly Related |
81 | ELI5: What are the SOLID principles in computer science? What's the reasoning behind them? | That's a pretty big question. Rather than go through all of them, I'll generalize and say that SOLID principles aim to help programmers write and organize their code in ways that make it easier for that code to be used and modified in the future. For example, S (Single responsibility) aims to make code easier to reuse and maintain, since anybody working with a specific class in the future knows that they only have to worry about making sure it fulfills its single role. O (Open/closed) ensures that that class code is never directly modified while still allowing the flexibility for future programmers to tailor the class to suit their needs. So on and so forth | Yeah, i feared that it was too big to explain in a single reddit comment. Could you please point me to a resource instead? | Slightly Related |
82 | ELI5 What stops the bacteria that rot corpses from eating living things? | Doctor here. You have an immune system, both passive (like skin, ear wax, vaginal secretions and tears) and active (your immune cells and proteins) and the active immunity has non specific (like macrophages devouring invading pathogens) or then presenting them to the specific cells (T and B cells and their antibodies). To have a functional immune system and cells, you need active circulation and constant proteins supply from the liver, once you die, you no longer have a circulation to recruit cells to invaded area, nor do you have liver to make C proteins and other inflammatory cytokines (messengers that recruit immune cells) | so are rot bacteria constantly trying to eat your flesh, but being repelled by your immune system? What's the deal? | Strongly Related |
83 | ELI5: What's the source of light scientists talk about? | The speed of light is quite poorly named, to be honest. Think of it more as the speed of reality. If I make a change to the universe HERE you will see that change happen when that reality - moving at "the speed of light" - reaches you. It doesn't matter if that change is a physical object, a light beam, gravitational pull, radio waves, whatever... the "reality" of it having changed moves outwards from that event at the speed of light. If you were 1 light-year away, and I turned on a torch, you won't see that torch turn on until my reality expands out to meet yours, which will take a year. If you were 1 light-year away, and I died, you couldn't ever possibly know that I'd died until the reality of my death has expanded so far that it touches your reality. There's no way to "cheat" it by sending a message announcing my death ahead, it would only ever reach you at the speed that the reality of the event expands. If the sun disappeared into nothingness this instant, being 8 light-minutes away, it would take 8 minutes before Earth suddenly WASN'T being pulled by the Sun, and stopped orbiting. We wouldn't know the Sun had gone optically for those 8 minutes either. Those 8 minutes are how long whatever-is-happening on the Sun takes to reach the part of the solar-system we live in. This is why when we look back at stars, we can say that a star is as it appeared a million years ago, etc. We know that because they are a million light-years away. Hence the "reality" of whatever happened to that star hasn't reached us until a million years later. That star is probably long dead and gone. The speed of light is the speed of reality. It's really the speed limit of the entire universe because of that. NOTHING can go faster than reality itself, but reality isn't instantaneously everywhere. It takes a while for the reality to catch up and expand out because the distances are so vast. If you \*could\* go faster than the speed of light, you could actually get somewhere, and then look back and watch yourself leave on that journey. And the "you" that left would have been able to see the "you" that's already there, before you leave! It basically turns almost into time travel, which is paradoxical and therefore we believe it's just not possible to do. You would be able to send a radio message to yourself in the past, and things like that, and we don't think that's "allowed" in physics without everything breaking. The speed of light is just called the speed of light, light is just an incidental example of it. Think of it as the speed of "reality" and it starts to make much more sense. Around a black hole, for instance, gravity has so curved space and time that the reality of whatever happens inside the black hole cannot ever make it out the black hole. Hence we know nothing about what happens inside a black hole and anyone inside of one knows nothing about what happens outside. It basically "chops" the realities in two, and they never meet again. | I like this idea but can you elaborate on other aspects of “reality” such as sound, heat, etc? Those are real too, right? Is it just that light is the fastest messenger of reality and so it got to give the name? | Strongly Related |
84 | ELI5: Why are most people heterosexual? | What is considered attractive has varied over the years, but hetero is the genetic default. Species don't survive without male/female sex and humans are wired to seek out a mate. Social and psychological pressures affect what we seek in a mate, but having children survive to pass on genes is hard-wired into us. | I guess I'm just curious about how the brain knows which way to be wired. Maybe it's triggered during prenatal development with the hormones and all that jazz? | Strongly Related |
85 | ELI5: How do people(like Matt Stonie) eat 10000+ calories meal? | 10.000 calories is 10 kilocalories which is a fraction of the daily recomended intake for an adult (somehere around 2400kcal/day) | In the United States, the term "calorie" is [commonly used](https://www.nutrition.gov/expert-q-a#:~:text=What%20is%20the%20difference%20between%20calories%20and%20kilocalories%3F,of%20water%20one%20degree%20Celsius.) to mean **Calorie**, which is equivalent to a kcal. > What is the difference between calories and kilocalories? > The "calorie" we refer to in food is actually kilocalorie. One (1) kilocalorie is the same as one (1) Calorie (upper case C). | Strongly Related |
86 | [ELI5] Why do we get goosebumps when we experience something that we really like? | It's a sort of layover from our fight or flight response. Back when we were hairy, if we got in to a (potentially) dangerous situation, we'd get an adrenaline rush. Accompanying that, our hairs would stand on end. This would make us look bigger to whatever predator was being a threat. We still get this reaction now, even though we're not as hairy. So, the mechanism that used to cause our hairs to stand up just gives us goosebumps instead. | Veey interesting, but why does this instict kick in? I am pleasured from what I see/hear/experience, not afraid, how is it a situation of potential danger | Slightly Related |
87 | ELI5: given how huge the ocean is and how relatively small submarines are, why do they collide? | Yes they do. [hear is a famous time](https://en.m.wikipedia.org/wiki/HMS_Vanguard_and_Le_Triomphant_submarine_collision) where an English and French sub collided | OP’s not asking “do they collide?”; OP’s asking “*why* do they collide?” | Related |
88 | ELI5 Why IPs are necessary for websites and why do IPs need to be associated with the URL rather than just using the URL as the definitive address? | There would be no way to route traffic efficiently without IP addressing. The only way it's done efficiently is by knowing based on network address where to route your traffic. Think of it more like sending something in the mail, vs a phone book. You need multiple pieces of information to get it to the right place right? You need Zip Code (US), State, City, Street Address, and Person. You mail that piece of mail from one side of the US to another, the first thing they do is look at that information to determine how it's going to get to it's destination. You can't just put a name on there, as there is no way for the mail service to know that name out of the 300 million people living in the US. So they start with ZIP code (which is really smaller than state), then narrow it down by street address, then eventually when it gets into your mailbox your wife hands you the mail because it ends up with your name on it. Same way IPs work. The numbers are not just randomly assigned. Network address space is reserved by classes. And routing tables know where those addresses are assigned to. We know that everything 8.x.x.x is going somewhere, and everything that 9.x.x.x is going somewhere. Then, as it gets closer to the destination, we use the additional digits to pinpoint where it's going until we get to the last digit and then we have the server. Also, its VERY important to know, that name does not equal 1 server or IP address. For example, when you go to [google.com](https://google.com) you go to 10000s of servers, not just a single server with a single IP address. Also, for smaller setups, 1 server can house multiple IP addresses. I have 5 domain names hosted on a single IP address. That's why you can't just go to a name. Really the name gets resolved to an address (or one in a pool of addresses), and then when you hit that server your browser says "Hey, I'm trying to get to [myfavoritedomain.com](https://myfavoritedomain.com)" and the web server serves it up. | This is my favourite answer so far - the post code analogy makes things much clearer than a phone book analogy, and especially makes it clear why IPs are advantageous over URLs in shared hosting situations. I do have a follow-up however - for URLs with multiple IPs attached, how does your router/browser/computer (not sure which would determine it in this case) know which IP to get in a given situation? | Strongly Related |
89 | ELI5 Why IPs are necessary for websites and why do IPs need to be associated with the URL rather than just using the URL as the definitive address? | IPs came years before URLs/domain names, so the backbone of the internet was based in IPs and a system to translate from a URL to an IP was created afterwards. Additionally, IPs are simply shorter to a computer. Generally speaking it takes 8 bits to represent a character. So a URL like 'google.com' is 80 bits long (10 bytes), and 'google.com' is a relatively short URL. An IPv4 address, is only 32 bits (4 bytes - effectively only 4 characters long, which is as long as many top-level domains [com, org, gov, etc] when you include the period) - less than half the size. | Okay, so IPs were used initially because numbers are shorter for a computer than letters? Does the introduction of DNS and URLs not add overhead that counteracts the initial data savings of using numerical IPs? | Strongly Related |
90 | [ELI5] How do supermarket logistics work and how does Lidl manage to deliver produce to customers at such low prices in comparison to others competitors? | Produce is dirt cheap. The retail price you pay is likely 10-20x more than the wholesale price the store pays at any grocery store. Stores like Lidl and Aldi can sell cheap because they economize by hiring fewer staff, having worse pay and benefits, and only selling a limited selection of mostly shelf-stable products. | Mmh Aldi pays $16/hr. I suppose they might have fewer employees though? | Related |
91 | ELI5: how do metro cards work? | It’s basically just a card that has a balance of money loaded onto it that you use to pay for subway tickets and bus fare | Yes but how? How does it know what balance it has? | Strongly Related |
92 | ELI5: If the brain signals for moving your hand and thinking of moving your hand are the same, what is the physiological difference that causes your hand to actually move? | Thinking happens in brain. When signal is sent to the arm, it moves. You don't think with your arms so the thinking signals just circle around in your head. | Yes but if they are the same signal, why doesn't it go to your arm if you're just thinking about it? | Strongly Related |
93 | ELI5 how do the cameras work that can see through clothing? | Not an expert so ill give you an educated guess until someone gives better details. I've seen some of those pictures a long time ago but i dont remember super well. Anyways its just like X-ray. Its something that pierces your clothes but bounces back from the skin sonar style. So yeah its not a clear picture but a 3d model of the person. Still very good quality. You can see peenises, titties etc. Wear iron armor beneath your clothes and noone will ever see you naked. | How this is even legal? | Slightly Related |
94 | ELI5: How does using contactless debit cards reduce fraud? {Please read below} | There are two things that make contactless pretty secure: 1. You can't currently clone a contactless card. Magnetic strip is trivial to clone, but for a chip this is extremely difficult, and for all practical purposes impossible. This means for someone to use your card, they'll have to physically steal it from you. The moment you notice your card is missing you just cancel it. Also they can't be used for "card not present" purchases online. 2. You have to be a registered person/business to accept contactless payments. There was a worry that people would go around skimming money from people's wallets with a contactless card reader. However this is going to leave a very irrefutable audit trail for every bit of money stolen and once the bank cottons on it would be trivial to pin the blame on the theif. | I see... I get that you can cancel your card as soon as someone physically steals it, but how does the fact that less money is taken out (because of the limit) reduce fraud? Can't the theif just withdraw multiple times and get the money?? Thank you :) | Related |
95 | eli5 how come only our fingers and toes get ‘pruny’ when we’re in water for a long time, but not the rest of our skin? | Because the act of pruning is a traction control reflex for long-term ocean life. You don’t need your thighs to have good traction when holding things in water. | I've noticed that when I give my baby a bath, her fingers and toes "prune up" really fast. Why is that? Is it because her hands and feet are so little? | Strongly Related |
96 | ELI5:When humans use hand eye coordination, like hitting a baseball with a baseball bat, are we doing mathematical calculations? | Kind of, but not quite. We *are* looking at things like how fast the ball is moving and imagining where it will be and then how hard we need to swing the bat and at what angle in order to hit the ball. These are all things that can be modeled through math, but knowing math or being able to model that is **not** necessary to swing a bat and hit a ball. | So our brain isn’t going 2+1 plus minus 7 SWING? | Related |
97 | ELI5: How do your eyes 'adjust' to the dark? | When lots of light, your pupils get small to let in less When little light, your pupils get bigger to let in more light | Why say many words when few words do trick? | Strongly Related |
98 | ELI5: Why do screens such as TV’s or computer monitors flicker when watching a recorded video of it? | It's the difference between the display refresh and the recorders refresh. Say your tv is 50Hz, and your video camera films at 60Hz. The camera is filming at a higher number of frames per second than your tv is displaying it, so it's going to show the "bits between" each frame on the tv | Why are there "bits between" instead of just having 1/5th of the frames doubled up because they got captured before the other one was changed? | Strongly Related |
99 | Eli5 How does color arise? | If you imagine light as a stream of particles, all with the same speed, you can imagine these particles to have different mass (note: that's a metaphor, actual photons don't have mass). "Heavier" particles carry more energy, and correspond to photons of a shorter wavelength. What we call "light" is actually only a tiny part of the whole electromagnetic spectrum, which is another name for "all the possible wavelengths photons can have". But it's the only part where we have sensory cells in our eyes that react directly to photons (we can kinda feel photons outside of that range on our skin, but what we actually feel is just how our skin gets warmer as it absorbs them). We have different types of these cells that react to different wavelengths, and our brain interprets these different wavelengths as colors. | What causes different photons to have different metaphorical masses? | Strongly Related |
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FollowupQG is a dataset of over 3K real-world (initial question, answer, follow-up question) tuples collected from a Reddit forum providing layman-friendly explanations for open-ended questions. In contrast to existing datasets, questions in FollowupQG use more diverse pragmatic strategies to seek information, and they also show higher-order cognitive skills (such as applying and relating).
Paper: FollowupQG: Towards information-seeking follow-up question generation
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