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{ "a_id": [ "h3d4n4v", "h3d4ljh", "h3d578w" ], "text": [ "It does, but it doesn't do it very well. Tattoo ink is placed between two different layers of skin. The dermis (the lower layer of skin) doesn't slough off like the epidermis does, so the ink remains there as new skin is produced. The body _does_ try to get rid of the ink, but the ink crystals are just too big for the body's natural immune system to remove quickly. Over time, it will 'chip away' at it, which is why tattoos fade. This is how tattoo removal lasers work, FWIW. They introduce high energy light to the crystals so those crystals shatter, making them small enough for the immune system to deal with and remove.", "The body does try to get rid of the ink. The issue is that white blood cells are too small to absorb the particles of pigment present in tattoo ink.", "I'm not a medical professional, but ... So the ink from a tattoo goes down to the dermis layer of skin. Basically creating a wound. The white blood cells attack it like they do any wound to try to heal it. On a basic level, the white blood cells carry away any \"foreign objects\" to heal the wound. The ink is too large a particle for those cells to remove, so the ink remains in the dermis layer of skin permanently." ], "score": [ 31, 3, 3 ], "text_urls": [ [], [], [] ] }

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{ "a_id": [ "h3d7408" ], "text": [ "The Dutch East India Trading Company mainly. They established strong colonies in areas that could grow coffee in the 1600s and became the primary supplier to the region." ], "score": [ 4 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3daknn", "h3dd4ax", "h3e26g7", "h3ei0kb" ], "text": [ "They don't stop once they reach a certain length. They stop when they've been growing for a certain amount of time. Hair follicles have a cycle where they'll grow for x number of days, rest for y number of days, then start again. The length they grow to is just the length they can reach in that time. After that, they stop and eventually fall out. Then, new hairs grow and take their place. The same happen on most of the body. Really, it's only the hairs on the top of the head (and maybe the chin) that are different.", "It's not that they stop growing at a certain length, but after a certain amount of time. Their length is simply however long they are when that time comes. Genes and health can influence how fast they grow or how long the growth phase lasts. Once the growth phase ends, the hair follicle closes up and just holds onto the hair for a while, then eventually sheds the hair once it's been out long enough to have sustained some damage and it's time to replace it with a new one. The hairs on your head have a much longer growth phase than the hairs on the rest of your body.", "Not all hairs are created equally. Most have a maximum length they can achieve before regular wear-and-tear causes them to fall off. Arm hairs will stop growing after a couple of months, whereas the hair on the head grows for a few years before it stops. Hair growth occurs in phases. The first phase is called the anagen phase, and it's the only time that hair actively grows. How long your own anagen phase is will be dependent on your genes. This is why some people just can't grow beards, or can't ever seem to get their hair as long as they want it to be. The typical anagen phase for a healthy adult for head-hair is between 2 and 6 years, long enough to grow around 1 to 3 feet. The typical anagen phase for arm hair is between 3 and 8 weeks, maxing it out at one or two inches. Once the anagen phase is over, it enters into the catagen phase. All the growing is done, but you might actually gain a little bit of length hear as the follicle pushes the hair out before it begins to grow another strand of hair. After catagen comes telogen, the resting phase, where the follicle sits dormant for a while (up to several months). This is when the old, dead hair falls off/gets pushed out. After that, it goes back to the anagen phase. And thankfully, all of this is staggered all over our (human) bodies. At any given moment, some of our hair is in any one of the three phases. Whereas for animals like long-furred dogs or sheep, it all happens at at the same time in the form of summer/winter shedding.", "None of your hair will grow forever. ALL hair will reach a maximum length. this is because every hair follicle on your body will eventually shed its hair and go into a resting phase for a while, then start growing again. The only difference is how long the growing phase is. For the hair on your head, it is very, very long. Head hair can grow down past the buttocks of some people. Some maybe longer. The arm and leg hairs, on the other hand, have much shorter cycles, so they never grow very long. That's the only difference at least as concerns your question." ], "score": [ 65, 10, 9, 8 ], "text_urls": [ [], [], [], [] ] }

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{ "a_id": [ "h3dgs43", "h3djpsi", "h3dhr98", "h3dglf3", "h3eida3", "h3dnqtw", "h3g7mdt" ], "text": [ "So presumably, you know at this point how a 3D sphere looks passing through a 2D universe, right? It starts off not existing, then it becomes a small circle, grows to a larger circle, shrinks to a smaller circle and then ceases to exist again. a 4D hypersphere does the same thing in the 3D universe: It spontaneously appears as a small 3D sphere, grows larger, then shrinks and finally disappears. That's the best visualisation of four dimensions that we can possibly have, because our brains are only three dimensional. We are literally incapable of visualising higher dimensions, similar to how we can't possibly imagine a colour that doesn't exist. We can talk about and think about how that would occur and how it would interact with the world, but we can't imagine what it would look like.", "[this]( URL_0 ) is one of the best explanations I have seen on all the higher dimensions.", "A two dimensional shape has single dimensional lines as sides. A three dimensional shape has two dimensional shapes as sides. Higher dimensional shapes follow this. A four dimensional hypercube consists of 8 cubes joined together. Our brains are not wired to imagine this and we obviously can't build physical models. However, you can look at a gif [like this one]( URL_0 ) for an approximation. If you look carefully, you can see that this object consists of 8 boxes. They have to warp the boxes to make them visible on your screen here. The real 4 dimensional hypercube uses the extra dimension to straighten them out. The way that mathematicians handle higher dimensional shapes is basically they understand what shapes make up the sides of the shape they're working on, and then they use some handy math to figure out what the angles are.", "Visualization is tough here, because your brain is designed for 3D visuals. You can kind of hijack time as a fourth - a 4D sphere with time as a fourth dimension, for example, would be a solid ball that appears as a point, expands into a sphere, and then contracts down into a point. But five and higher is tough. It may be simpler to just think of it more mathematically. You describe a point in 3D space with three coordinates (x,y,z). You can describe a 4D point with four coordinates (a,b,c,d), a 5D point with five (a,b,c,d,e), and so on. You can even have infinite-dimensional spaces, although those become counterintuitive really quickly. Like, what is it you feel you're not understanding here?", "Don't know if this is what you mean, but certainly helped me grasp the concept. Carl Sagan flat land. URL_0 Dr quantum flat land. URL_1 Hopefully this helps you hyperthetically visualise other dimensions.", "> i get how there can be a higher dimension but I just can't comprehend it Kinda how it works! A theoretical 2D being just *couldn't* visualize a third dimension, and it's the same for us 3D beings trying to visualize a 4th. Try this: Imagine a 3D graph. You can make one if it helps: draw a horizontal X axis and a vertical Y axis on a piece of paper, then put the tip of your pencil at the point where X and Y cross and hold the eraser end in the air - now your pencil is a Z axis. You can define a point by its X, Y, and Z coordinates and that point will be floating in the air somewhere. Got it? OK - that's 3 dimensions. Easy peasy so far. Now imagine *another* 3D graph. Now here's the part where you add a 4th dimension: imagine *another* axis connecting the 0,0,0 point on one of those 3D graphs to the 0,0,0 point on the *other* graph - let's call this new axis \"T\". Now you can define a point not just by its X, Y, and Z coordinates, but *also* by its T coordinate. If X, Y, and Z are defining a point in *space*, then T is defining a point in *time* - and now you have four dimensions.", "There's an old story about 3 blind men who encounter an elephant. The first one grabs its leg, and he says \"oh, an elephant is like a tree\". The second one grabs its trunk, and says \"no, an elephant is like a snake\". The third one grabs its tail, and says \"no, an elephant is like a rope\". Then they get into an argument with each other. If you were to observe a higher dimensional object, you'd be like one of those blind men. You can only perceive the object as it appears 3 dimensionally. You're basically seeing a tiny fraction of the whole. We have to use analogies to describe it, because since we don't operate in higher dimensions, our brains can't picture it properly. If you were to describe a man, you might say he's 6 feet tall, weighs 200 lbs, has brown hair and blue eyes, he's wearing a gray suit and he's got a gold watch. You could describe him 3 dimensionally. But if you look at him 4th dimensionally, he's also a 5 year old child eating an ice cream cone, and he's a teenager fumbling around in the back seat of his car with his prom date, and he's an old man in the nursing home. You'd be able to see all of these things at once if you could somehow see his entire life. We can sort of imagine the fourth dimension as time. What about a fifth dimension, sixth dimension, or seventh dimension? We can describe it with mathematics, but nobody has any idea what it would really \"look\" like. We just get into bad analogies then." ], "score": [ 30, 15, 10, 5, 3, 3, 3 ], "text_urls": [ [], [ "https://youtu.be/0ca4miMMaCE" ], [ "https://giphy.com/gifs/tesseract-AvCPKNLbH6FoI" ], [], [ "https://youtu.be/UnURElCzGc0", "https://youtu.be/sEVEKL1Fbx0" ], [], [] ] }

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{ "a_id": [ "h3dlvkk", "h3dmd2d" ], "text": [ "Fluoride gets deposited on the surface of your teeth and makes them more resistant to the acids produced by bacteria in your mouth. (It also may directly slow the growth of the bacteria themselves; that's less certain.) That makes you less vulnerable to tooth decay.", "Fluoride helps slow tooth decay because it basically bonds to the enamel (the harder outer part of the tooth) and and forms a protective layer/barrier. Fluoride, for this same reason, was added to water supplies across the USA, and in the years following them adding fluoride to water, cavity rates in those areas dropped. This then made everyone think that adding fluoride to water was working, but, what a recent study pointed out is that people originally failed to consider that at the same time that people were adding fluoride to water, they were also adding fluoride to toothpaste. Now it’s believed that a lot of the success really comes from the fluoride in toothpaste, and not the fluoride in the water. There were always some health concerns, because fluoride in large amounts can be toxic and cause some brain/nerve damage. Which is why you don’t swallow toothpaste. But it isn’t believed that the levels it exists in water is high enough to cause that, but studies are still being done on it. Tl/dr: fluoride in toothpaste is seen overall as a good thing (but don’t swallow it!), and for fluoride in water, the jury is still out on if it is good or bad, but it probably isn’t harmful with the levels it is in the water." ], "score": [ 3, 3 ], "text_urls": [ [], [] ] }

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{ "a_id": [ "h3dsazj", "h3duhjk", "h3dse44" ], "text": [ "To you it looks transparent, but so is uv radiation. Uv radiation is simply not visible to humans and the sunscreen reflects it. There are some cool videos on youtube where you can see through some special camera how the rays are reflected", "Sunscreen blocks ultraviolet light, absorbing it before it can get into your skin and damage skin cells. It's transparent (or nearly transparent) to all the forms of light we can see in the same way that glass is. [This video]( URL_0 ) uses a camera with an ultraviolet light sensor to show you what sunscreen would look like if we could see UV light.", "Sunscreen is paint. You paint it on your skin to form a protective coating. Some is white, like the lifeguard puts on their nose. Some is transparent to the colors humans can see." ], "score": [ 6, 6, 3 ], "text_urls": [ [], [ "https://www.youtube.com/watch?v=GRD-xvlhGMc" ], [] ] }

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{ "a_id": [ "h3dx8ie" ], "text": [ "> What happens when someone mints an NFT without having a right to the artwork for instance? Then they created an NFT and control it, until potentially selling it to someone else. The NFT does not confer ownership of the original work, just control of the hash of... something. Commonly it would actually just be the hash of a URL which points to an image file of the artwork. If the artwork is actually owned by someone else then they could demand the host of the URL take it down. At that point the NFT owner controls the hash of a URL that points nowhere. No NFT actually establishes the ownership of an artwork, it is at best a paper trail of receipts. Local law establishes ownership no matter what happens with the NFT. > But what happens to the blockchain if errors like this occur? There is no error. The NFT still exists and whoever controls it still \"owns\" the NFT. It is just slightly more pointless than it was from the start. > Can the information in the ledger be erased or changed and if so, how? Nope, that is the whole point. But that information only indicates who controls the NFT itself, not anything to do with ownership of the artwork." ], "score": [ 10 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3e0ob9", "h3dyhgp" ], "text": [ "Different plants have different needs. Some actually don't mind being \"root bound\" that much (having their pot fill up with roots) and actually can do better with it. Others really find it horrible. As an example, let's look at a cactus. Most are designed to live in hot dry areas where water is rare. So if a cactus is in a small pot and sucks all the water out of the little bit of soil that's left because its roots have stuffed the entire pot, it's gonna be okay for a while. It's good with being \"dried out\" and it grows slow anyway. Another example: some low-light jungle plants like spider plant are used to growing in small patches of soil up in trees, so they can tolerate being rootbound too. Other plants aren't as hardy in the same way. They are designed to spread roots wide, and it's a shock to them to be stuck in a tiny container. It strangles their root system, which for a lot of plants needs a little breathing room, same as the leaves do. So they won't do as well.", "Because the stress (yes) or starvation will kill it. If there's no room left to provide enough nutrients, the plant will eventually die." ], "score": [ 13, 3 ], "text_urls": [ [], [] ] }

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{ "a_id": [ "h3e7vmz", "h3e9i7v", "h3fp82n" ], "text": [ "Animals can get sunburned like we do, pigs for example root in mud to cool off and because mud is a form of sun protection. Animals with fur cannot get sunburned where and when the fur covers them but can get burned on their lips and eyelids.", "Yes! My dog loves to lay in the sun on her back. I can tell when she's been doing it, because her pink tummy starts turning dark brown.", "Sharks can tan (their upper body colour gets darker), although they can't seem to get skin cancer" ], "score": [ 38, 25, 5 ], "text_urls": [ [], [], [] ] }

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{ "a_id": [ "h3e878y" ], "text": [ "Humans have no inherently powerful natural sensory organs, our sense of smell is inferior to dogs and our sense of sight is inferior to most birds. Our greatest natural advantage is our intelligence and ability to communicate complex information to each other." ], "score": [ 12 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3e95j4" ], "text": [ "Because it makes you feel like others understand how you feel and your not the only one who has been through this before. And sometimes the song can explain how you feel better than anything else could." ], "score": [ 7 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3ebho2", "h3ecaoh", "h3eiagc" ], "text": [ "Perspective. Parallel lines look like they're converging at the \"vanishing point\", aka infinity. The sun is so far away that it might as well be infinity as far as our eyeballs are concerned.", "It’s the same effect you get standing between train tracks. The tracks are parallel, just like the light rays, but further away they take up less of your field of view, so they look like they are converging.", "I get the answer to this question... But why would light rays from the sun be considered parallel? Doesn't the sun randomly emit photons in all directions?" ], "score": [ 32, 12, 6 ], "text_urls": [ [], [], [] ] }

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{ "a_id": [ "h3ecbwy", "h3ecgn0", "h3fs8wz", "h3emopl", "h3ewrk2", "h3fzn7a", "h3gx184", "h3g80if", "h3ge61s" ], "text": [ "Removing it is additional work and risk that isn’t really useful unless the kidney is infected or something. Usually it’s fine and just not working, so it’s easier and safer to leave it in instead of chopping around in there.", "Kidneys filter the blood and so, as you might expect, have massive blood supply from the body. Removing them requires sealing off all those vessels and is just more trouble than it is worth. The kidney may still have some function left so it can still help, so they are all left in if possible.", "I'm a doctor but not a transplant surgeon. I apologize if I butcher anything (pun intended). The easy answer is a transplant kidney and native kidney are in different places. Your body is actually a series of compartments. In your abdomen, the biggest one if the peritoneum (sorry for big words) but we'll call it \"the belly cavity\" Your native kidney are in a tighter, more cramped, and harder to get to place in your back called the retroperitoneum (behind the peritoneum or \"behind the belly cavity\") And doctors typically want to do the easiest and safest thing. So instead of placing your new kidney in the harder to get place, we put in somewhere totally different where it's easy to hook up to your bladder and blood vessels. Because honestly, it can be anywhere as long as you have those hookups. Putting it close to the bladder and blood vessels also lowers the chance of the suturing falling apart from stretching. Most commonly, that's actually in the front, bottom part of your abdomen. And the transplant surgeon doesn't even go into the \"belly cavity\" itself, they put it in the space deep to your muscle but not yet in the belly do they don't have to deal with your intestines and all that stuff (Extraperitoneal if you want to be fancy). And there's also a risk of the transplant kidney \"spinning on itself\" if it's in the belly cavity since there's more room and that can twist off the blood supply and kill the transplant. Also, most of the time when people need a transplant the kidneys are shrunken up, way smaller, and it's okay just to kind of leave them there because they're inert. People with kidneys that fail because they have a ton of cysts on them, however, may still have massive kidneys. How much space they take up and bleeding into those cysts can cause pain so they are sometimes removed. Kidneys are removed for cancer, naturally. Also, scarred up kidneys from infection can sometimes make your blood pressure go higher so they are removed. But your run of the mill guy with diabeetus and the high blood (pressure) are going to have these small raisin kidneys you just ignore", "Kidney transplant is more dangerous on the donor. There are so many blood vessels going to the kidney that removing a kidney means a lot of arteries to seal and big risks of massive internal bleeding. So if they don't have to remove it, for instance no cancer or infection, the kidney is simply not doing his job, it is safer to leave it there and just continue to do nothing.", "A kidney is not like most organs. You can have “extras” without them interfering in the daily running of your body. Actually, extra kidneys is good! You can only have one heart because of the way your body is laid out. Your heart is kinda in the middle-ish of your body, and all of your blood *has* to go to your heart, make a detour through your lungs to pick up oxygen, and then swish around your body to drop the oxygen off. If you had two hearts, this carefully-choreographed system just wouldn’t work. But kidneys. Kidneys are special. They’re unusual. They kinda just float in your abdomen, at the back. Some people only have one, and some people have three naturally. It doesn’t make much difference. Weird, right? Kidneys filter your blood. All your blood passes through them, and they push out the excess water and salt, and other dissolved waste products. This trickles down into your bladder and you pee it out. Now, you can pretty much attach as many of these kidney tubes as you like to your bladder. So if a kidney still has some function, there is no reason to cut it out. It’s helping, even if it is not enough by itself to keep a person alive. In a person with kidney problems, it’s pertinent to give them every bit of help possible. And you can have three kidneys with no problems at all. That’s why they leave it in unless it’s literally dead or dying.", "Kidney Donor: “I’ll only have one kidney working at 100% but it’s worth it so you can continue to live” Guy receiving kidney: “I appreciate you but ackchyually I’ll have 120% function” Kidney Donor: “WAT”", "Kidney doctor here, who did training at a major academic transplant center. Much of what has been said already is very accurate. The kidneys are a very complex set of arteries and hormone-secreting little nuggets, and they together get ~20% of the cardiac output. Taking a kidney out is no small feat, as even though the function of the kidney has declined, there is still a tremendous amount of blood flowing through it. There just isn’t the benefit worth the risk of taking out a non functioning kidney if it isn’t causing problems. In terms of when transplanted kidneys fail (which they still do with time unfortunately, we are still working on improving the longevity), again the risk of removing them from their grafted (“sewn-on”) position is not worth it unless there is compelling evidence. And lastly, even if the relatively nonfunctioning transplanted kidney isn’t filtering the blood, there is interesting evidence that the antigens, things that tell your body that the tissue is yours and to allow it to stay, seem to INcrease after removal of the donor kidney. The more of these antigens you have the harder it is to find a subsequent kidney match for transplant. So again with failed transplants unless there is a marked compelling reason (pain, infection, bleeding) we leave the transplanted kidneys. It is not unheard of to need 2-3 transplants (thus 4-5 total kidneys in someone’s body).", "I have a kidney transplant. They left my failing kidneys in and just added a third. It sits over my right upper hip. Unless there is an infection, you have polysistic kidney disease or you have a really small frame they say it's better to leave the old ones in. When you consider how much time it takes get the surgery (3- 10yrs, depending on where you live) most people have less than 5% function, so it's not like you get \"extra\" function. People with end stage renal disease are very sick and basically on life support (dialysis).", "According to Wikipedia, it is evidence-based. Removing the malfunctioning kidney increased the risk risk of death; reduced long and short term survival rates. Your original kidneys are located closer to your back, partially protected by the rib cage. (Kidney pain is often misidentified as back pain, rather than abdominal pain) The donor kidney is \"installed\" in your abdomen (just under / in front of your intestines, above the hips). They tap into a different artery as well so generally they aren't even coming close to your existing kidneys. For the recipient it's less matter of \"leaving the old one in\" and more a matter of tacking-on an extra one. The first attempt was performed close to 1900, and it was installed in the thigh! (Failed because of rejection) In another early case, the donor kidney only lasted 8 months, but it allowed the original kidneys to heal - yet another great motivation for leaving them in! 😁" ], "score": [ 651, 549, 99, 45, 42, 8, 6, 5, 3 ], "text_urls": [ [], [], [], [], [], [], [], [], [] ] }

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{ "a_id": [ "h3eqg8p" ], "text": [ "When you peel off a sticker, you’re basically pulling on the top side while the bottom is still stuck. This lengthens the fibres on the bottom while the top ones are still in place. One longer side = curls! This also applies to when you curl a ribbon by running one side agains a scissor blade." ], "score": [ 7 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3etene" ], "text": [ "Because the water bounces on a cold surface, floor or side of the shower, losing temperature in the process, so when it touches you again it feels colder because it is. Our skin is sensitive so even a few degrees can make the difference between cold an warm" ], "score": [ 29 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3exntw", "h3f7ccm", "h3ez9dh" ], "text": [ "My understanding is this: Alcohol (ethanol) is freely floating about in the water (like the rest of the \"drink stuff\") and is loosely connected to the mix. THC is much more firmly packed in with the \"food stuff.\" Water (and basically everything we drink is 90+% water) gets an express pass from the stomach to the intestine while food has to mill about getting processed by the stomach. So, alcohol can be pulled out of the drink with much less effort and arrives at the absorption site faster while the THC takes a whole lot of getting-at and takes longer to reach the place it gets absorbed.", "Alcohol is absorbed via the stomach and small intestine. THC is absorbed by the small intestine, so it has to travel further. THC dissolves in ethanol, which is why crossfade is a thing. Basically alcohol helps the THC get absorbed in the stomach.", "Liquid THC drinks work a lot quicker than gummies, but still not as fast as alcohol in my experience." ], "score": [ 17, 5, 4 ], "text_urls": [ [], [], [] ] }

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{ "a_id": [ "h3f0qst", "h3eyo6r", "h3fc9er", "h3fyr28" ], "text": [ "C Major chord has the notes C - E - G. C minor chord has the notes C - E flat - G As you can see, the note that distinguishes the two chords is that differing middle note. And a power chord is missing that middle note, so it is neither Major nor minor. For example, the C power chord is C-G.", "A basic chord on a guitar will usually be a root note, a fifth note, and a third. The third changes it from major, to minor if you flatten that note. The third usually gives that tonal characteristic of the full chord. A power chord omits the third and it's only the root, a fifth, and sometimes a third finger on a higher octave of the root. So it's still only a 1 and a 5 together with no 3. This ambiguous non-major / non-minor kind of chord results in harmonics that work very well together, especially on a distorted guitar, the frequencies of the root and the 5th together produce a very *power*ful sound with great harmonics.", "A power chord doesn't have a 'third'. It consists of the root note (e.g. G in a G chord) and the fifth above. It also usually has the root note an octave higher to make the sound thicker. The third is what makes a normal chord major or minor. Since a power chord doesn't have one, it is neither major or minor, so does not have the defining quality of sound that a major or minor chord does. It makes them much more easy to use. Also, they are easy to play.", "Whole lot of explainations, not a lot of \"like I'm five.\" A typical chord is three notes. One of these notes will make the chord sound either happy or sad. If you take that note out, the chord sounds more neutral. In a rock song, neutral can sound pretty heavy and powerful, thus \"power chord.\"" ], "score": [ 48, 13, 12, 8 ], "text_urls": [ [], [], [], [] ] }

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{ "a_id": [ "h3f93ki", "h3f9b8y", "h3f9e3h" ], "text": [ "The answer is dimensions. Things that scale in two or three dimensions tend to use square and cube numbers respectively. To take the law of universal gravitation as an example - when talking about gravity, you have a massive object with a nonzero volume (usually a sphere) that has gravity. The surface of this object is essentially two-dimensional. As you move away from the object (increasing R) gravity \"spreads out\" in these two dimensions, which results in the force of gravity decreasing with the square of distance. Light works the same way, light coming from a spherical source (like the sun) spreads out in two dimensions, which means the amount of sunlight you get decreases with the square of distance from the sun.", "There is plenty of opportunity to go all tinfoil hat on the topic and philosophize until the end of times. But, more likely, it's just that the universe isn't actually all that complicated. It's extremely _complex_, but not very complicated. With only a handful of equations, you can describe virtually all of it. That might be some secret holy code we discovered, or it might simply be that that's just all it really takes to make a universe. Look at it from another topic, say evolution. Natural selection is an incredibly simple idea. You survive more, you reproduce more, end of story. About as simple of a concept as you can make, really. And yet it's capable of producing all of life, just like that. Similarly, if you simply invent time and gravity, you can already make a whole bunch of things that look very complicated, but really aren't. You'll wonder why planets are round, why they spin, why they orbit the way they do - millions and millions of questions, all from two simple laws. If you want to look at that like it's magic - fair enough, I suppose. In a way it is kinda weird that these things are even understandable by the human brain. But you can also look at it from a more cynical point of view and just conclude that maybe it's just not necessary to have an insanely complicated setup to make a universe. Maybe a few laws are just enough and _we_ are the mistake here, with our strange presumption that it _should_ be complicated. Because, really, why should it be? More to the point though, cubes and their roots aren't very surprising when you remember that we live in a universe with, presumably, 3 dimensions of space. From that fact alone you get a lot of numbers that seem to pop up all the time. But really, they are just from the fact that the universe happens to have three dimensions. \"Nature\" also isn't really a thing, it's just an extension of physics. Which, you surely noticed, also likes a lot of simple things. Spheres, disks, circles - that kind of thing. All over the damn place. But, again, no big bad voodoo conspiracy - just 3 spatial dimensions. Spheres are just the most effective way to pack stuff, that's all there's to it. Physics likes low energy stuff and randomly making triangle planets is just not that. Now combine the fact that spheres are great, low-energy stuff, sprinkle in 3 dimensions and before you know what's happening you have PI showing up all over the place. And because nature is just biology and biology is just physics - life also likes low energy stuff. Bees make their hexagons, trees aren't squares, mushrooms spread out in a sphere if you let them. Nothing fancy happening, just physics seeking low energy. The numbers you mentioned just happen to often describe these lower energy states, the things where little more than our 3 dimensions are at play. Take your Newton example. What's in that formula? Gravity and dimensionality - that's it. It's essentially just a constant multiplied by the amount of dimensions we have, that's really all that formula is. It looks spooky when you view it from a lens of this awfully complex universe, but if you really reduce it to what the problem is actually about, it's just actually really simple. In other words, bees don't make hexagons because they're pretty and they like math, they make them because the hexagon is the most efficient structure to make. As such, nature makes them all the time. Same with spheres and circles and discs and spirals and all that stuff. It's not that all of nature conspired to confirm our math, it's that our math describes the tendency of our 4 dimensional spacetime. ... not sure if that really answers anything, but I'm not sure if there really is a good answer here, it's awfully philosophical.", "Things falling off with the square of distance is natural, because the surface area of a sphere goes up with the square of size. Intensity of light works that way too. The fact that surface areas go up with the square of size, and volumes go up with the cube of size, is (Euclidean) geometry and mathematics, more than physics." ], "score": [ 121, 11, 4 ], "text_urls": [ [], [], [] ] }

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{ "a_id": [ "h3feb8e", "h3f9rtq" ], "text": [ "You are comparing thermal IR vs near IR. Military use both. The thermal cameras have higher resolution and accuracy result in higher cost and larger size. We talk about 100x the cost of a phone thermal IR camera Military thermal cameras are what is commonly used in tanks and other armored vehicles. There exist man-portable variants too, but not use by every soldier because of cost and size. The displays then are grayscale because you look for the hot object and not care about temperature scales the same way. They are not just for night use but can be used during the day, You can see humans that is for example looking out from cover in thermal camreras during the day The result in images is similar to the camera you use to see house thermal leak. Near IR is it light close to visible light. Night-vision goggles (NVG) are common for individuals said. They magnify the light, both visible light, and infrared light. So they can be used to amplify the small amount of light that is out there so you can use them passively at night. They can't be used during the day only at night. You can also use an infrared flashlight so you can see better of stuff that is close by. This is especially useful if there is not a lot of ambient light like in dark indoor. There is a drawback to an IR flashlight and that is an enemy with night vision equipment can see it to and ar a farther distance than you can see them. It is like if you go in the dark with a regular flashlight. So active IR illumination is a bad idea against a technology equal opponent but can be useful again less advanced enemies link again terrorist groups. The active IR illumination existed experimentally in WWII and has later used on tanks. In the early 1980s thermal camera started to replace active IR illumination in tanks because cameras become available. Now you can observe the enemy and night without lighting yourself with a large IR light source that gives your location away. So military night vision equipment will be thermal IR cameras for tanks and other armored vehicles. Both for day and night use. Individual soldiers use night-vision goggles (NVG) that amplify visibly and near IR light and give you something that looks like we are used to but can't be used during the day, they would just show white then.", "Two completely different technologies. Heat cameras aren't looking for light, they are sensing temperatures and converting that to an image. That's why the images look all blobby and blurry. A lot have a feature where they do capture an image and use it as an overlay/underlay to the temperature info to make it easier to interpret. IR cameras emit infrared light like a flashlight, and then capture the reflection just like any other camera. Since it is primarily only capturing the infrared light rather than the full spectrum, the image is presented to the user as black and white rather than color" ], "score": [ 8, 4 ], "text_urls": [ [], [] ] }

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{ "a_id": [ "h3fjub4", "h3fds5g", "h3fdq7t", "h3ffbm9", "h3fdt4l", "h3feqze", "h3fhw8c", "h3fua4c", "h3fpd9e" ], "text": [ "An increased demand for something doesn’t automatically raise prices. Generally it leads to increased production. However it can lead to higher prices when production caps out. Let’s say that you run a donut shop in town. Every day you make 100 donuts, and you sell them for $1 each. And every day, Bob comes in at 2 in the afternoon (Bob sleeps late) and buys your very last donut. You made 100 donuts, you sold 100 donuts. Then one day you notice construction workers in the big empty field across the street from your donut shop. They are building a new apartment complex. Six months later it is done, and a bunch of people move in. The first day it is open, a bunch of new people come in to try your donuts. You sell all of your donuts by 9 am. The rest of the day, your normal customers come in and are upset that you have no donuts for them. Poor Bob. So the next day, you make 200 donuts instead of 100. The big crowd comes over and today you sell out by 11:00. Poor Bob still doesn’t get a donut. The day after you make 250 donuts, and finally everyone gets a donut. Bob buys your last one at his usual time, and he is happy. And you are happy because you just sold two and a half times as many donuts. Great! But then you notice that they are building *another* new apartment complex next door to the first one. This is a problem, because your donut shop is small. You are working your butt off to make 250 donuts in that cramped space. You had to wake up at 3 in the morning to make all those donuts, and you don’t have room in your display case for more. If more people come in, you are going to need to hire somebody to help you. Unfortunately your shop is too small and the new employee wouldn’t have enough room to work. He would always be bumping into you. So six months go by and the second apartment building opens up. Today you sell out by 9:00 again. A whole bunch of people don’t get any donuts. Poor Bob doesn’t get his 2:00 donut. What are you going to do? You can’t expand production any more without buying a bigger space and hiring more employees. That’s expensive, and you don’t know if this increased demand is going to last. What happens if you spend a bunch of money for a bigger space and some of those people decide they don’t want donuts anymore? So what do you do? The answer is, you increase your prices. Donuts are now $1.50. Some customers are upset. They come in and say “I’m not paying a buck and a half for a donut!” And they leave. That’s good, as long as you still sell all your donuts. As long as 250 people come in and buy a donut at your new, higher price, you made more money. Bob comes in at 2:00 and you’ve got one last donut for him. “Sorry Bob, I had to raise my prices. They kept selling out and I wanted to make sure you could get one. That’ll be a buck and a half.” Bob grudgingly hands over an extra 50 cents and he gets his donut. When demand gets really high, it’s generally better to just make more of the product. But eventually you can’t make any more (or making more requires a lot of lead time, or carries risks, or needs a lot of up front investment). So you either raise your prices or there it becomes first come first served and there is a shortage.", "Increased demand = people willing to pay extra for the product, and a smart business knows that.", "Let's say you sell bottles of water. Typically you have 100 bottles of water and you regularly sell 100 bottles and you're the only supplier. One day, you only end up with 70 bottles of water, but still have 100 dollars. Since there's a shortage of supply, but you still want to make maximum profit, you can up that price because those 100 people will compete with higher prices for that water.", "It’s a law of economics. It stems from resource scarcity. If people want something, but there’s not enough of that thing to go around, the people who want it the most will pay more money for it, which will set the price at a higher level. A business will know this, they will also know that if the cost of manufacturing a product goes up, they will have to charge a higher price to cover the cost of production, and they may be unable to produce as much of it. Basically scarcity affects both supply and demand. If there’s less of a product on the market, but the number of people who want that product hasn’t changed, or increased, the price will naturally go up.", "It's not some immutable law of the universe, but it kind of just happens. The value of something is usually determined by the cost to produce it, plus a profit that the market will bear. Think of it this way. You have 100 snow globes and 100 people who want to buy them. You can balance out your cost to make them, be plus some money for yourself. One of the snow globes gets knocked off the table and breaks. Now 100 people want 99 snow globes. So someone isn't getting one. That means the value to people has just gone up because they still want one. This would be a change in supply. If you keep all 100 snow globes and 200 people show up, suddenly half the people aren't getting one, so many of those people will pay more.", "Its just people. Look what happened with graphics cards. There was huge demand for those, and not enough production. People bought them, and sold at higher price. That drives the prices. If manufacturer is selling a product at too low price, then someone else will buy cheep product, and sell it at market price. So reasonable action now is to sell at market price by manufacturer. Similar thing happens with basically every limited resource. I once encountered situation, where one beer won some prestigious competition. But producer said that he is not going to increase their price. In the second when this beer was once again produced, people bought all stock, and started selling at 2x or 3x margin. So in the end, producer is earning much less than is possible, and typical end consumers still have to pay extra high price.", "If a product is selling out faster than expected, that tells the business owner she might be able to sell the same quantity at a slightly higher price.", "This is the story my econ professor told us. Let's say you bring a pizza to class, but have 20 students. You could charge 25cents a piece and the first 8 people to walk up get a slice. Or you could charge $5 a slice and the 8 students who forgot their lunch that day will be the only people who walk up. Money is how we judge who wants something more and who gets it. It's a medium of trade. This breaks down though when you have billionaires and homeless people. The billionaire could buy the whole pizza for $100 without it meaning as much as the homeless person who could only afford $1 a slice.", "Most answers seem to be talking about the decision making behind this, but I don’t see a lot of coverage of the way this just naturally happens in a market. Let’s say there are two people who know how to make product X. They can each make 100 units a month, but one of them charges $100 per unit and the other charges $110. Naturally, all business is going to go to the person charging the cheaper rate. But if demand for a given month outstrips the supply of 100 units that person can produce, anyone else who wants one will have to turn to the more expensive supplier and pay $110 instead. The price has effectively gone up. Generally speaking, there will be people providing a product at a variety of prices. Low priced product gets snapped up first, moving up the price tiers until you either satisfy everyone’s needs or hit a price where no one is willing to pay it any longer. The price naturally rises when demand outstrips supply and people snatch up the lowest price items. The price naturally falls when supply outstrips demand and lower priced sellers wind up with extra stock. Then, likewise, sellers will generally try to tune their prices to the individual demand they are experiencing. If I can make 5 of something, but isn’t he same timeframe I only sell two, then I may need to lower my price in order to generate more overall income, since I have unused capacity. If I can sell out by lowering my price to anything more than 2/5ths of my current price, I make more money at the lower price. Likewise, if I can only make 5 units of something, but during the same timeframe I receive 10 requests for my product at my current price, then I would make more money if I raised prices until only 5 people were interested at the new price, since I can’t sell more than 5 units anyway." ], "score": [ 423, 41, 19, 19, 4, 4, 3, 3, 3 ], "text_urls": [ [], [], [], [], [], [], [], [], [] ] }

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{ "a_id": [ "h3feoz3" ], "text": [ "A no show is a job where you do not have to show up to get paid. At the end of the week there is a pay cheque waiting for you. A no work is where you have to be there, some of the time at least, but don't have to do any work. Chrissy had a no show job. So he got paid despite not being there. The guys- Eugene and Vito I think- who were sitting around at the building site playing cards had no work jobs. Both are just forms of corruption where they are skimming cash to show legitimate forms of income. Can't tell the tax man you live in a mansion, but have no formof income." ], "score": [ 34 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3flna5", "h3fhbu5", "h3fm45e" ], "text": [ "Let's think of operating systems as human languages. You write a book in English and you want a Swahili speaker to read it. What do you do? Translate the book to Swahili. This is analogous to game available to both Linux and Windows. What about Proton and Steam Play? Well, some books don't get published in Swahili so you'll have to hire a translator to read it to you. Some books are really easy to translate on the fly, but some use advanced concepts that the translator doesn't fully understand. So the translator makes some mistakes. They're obvious but you can still enjoy the book. Now, try to give a book about theoretical quantum physics to a translator who works mainly with literary works. With all the hard to understand concepts and specialized words maybe they'll just say no to the job.", "For proton one of the big issues nowadays is often whatever the game has (non steam) DRM, Denuvo for example does not play well with proton.", "Generally speaking. If the game is very old. Like, 2005 Or below. The game will work with no issues. There are exceptions to this though. Where the issues arise are with Proton to play games because, If theoretically proton got good enough to run almost all Windows games. There would be no reason for any developer to make a native linux version. And Linux would always be stuck with the \\~ 5% performance loss in games **except some games do run better on Proton than they do on Windows ironically.** Also. There would still be services like FaceIT or ESEA where they wouldn't want you to ever use proton to play it and they'd figure out someway to detect it." ], "score": [ 167, 6, 3 ], "text_urls": [ [], [], [] ] }

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{ "a_id": [ "h3fi947", "h3fi9mo", "h3fl5ba", "h3fkjdh", "h3fii6q" ], "text": [ "A reoccurring problem in a lot of ways is that companies do things if they think it will make them specifically money, they don't care if they make everything else in the world worse by doing it. Some streaming services fail but lots make lots of money, so there will be more and more until every single one is so diluted they are all useless.", "When it comes to streaming, They're trying to get a foothold in the market, this is a relatively new thing and is most likely going to replace television completely in the near future. It's good to get in early, some will fail, like the ones you can't remember, and some will succeed, like disney+ and Netflix.", "A steady revenue allows the company to more easily greenlight new content. Knowing not all your money is from a single blockbuster game/movie allows for more variety. But I agree that there are so many subscription services, but you don't need to be subscribed to all of them at the same time, rotating between disney/netflix/hbo every few months is totally possible.", "Because this is what we told them we wanted. Cable customers have been bitching for years about the cost of cable and how there's a bunch of channels they dont even watch that they are paying for. \"Why can't I just pay for the channels I want?\" Well, now you can. They are giving us the ala carte system we told them we wanted... And, in what should be shocking to no one, now we're complaining about having to maintain multiple ala carte options. We are fuckin infuriating...", "Because when they host the content, they get 100% of the revenue, and it brings an audience to that company's content that might not otherwise be popular, allowing them to compete in the market. To use an example, NBC previously licensed The Office to Netflix, where it was wildly popular and consistently one of Netflix's most watched titles. When NBC launched their streaming service, they made The Office exclusive to that service, allowing them to keep all the revenue instead of sharing with Netflix. Additionally, NBC can now present all their other less-popular content to subscribers who may have come to watch The Office, where it may get more exposure than it would have as part of a larger library such as Netflix. By keeping things exclusive to their platforms, providers are banking on people's desire to watch specific media on their platform overcoming their reluctance to pay extra for a subscription to that platform." ], "score": [ 12, 9, 5, 5, 3 ], "text_urls": [ [], [], [], [], [] ] }

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{ "a_id": [ "h3fzyi0" ], "text": [ "You know that is a marketing term? The pots aren't actual rock..." ], "score": [ 6 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3fnqtv", "h3g7gcu", "h3fnvy1", "h3gvp44", "h3g6t8n", "h3g6u1h", "h3hlv05", "h3hewns", "h3g9qfu", "h3gcz15", "h3hx62v", "h3gslmx" ], "text": [ "Well because p=mv isnt the only way to describe momentum. De Broglie said that p=h/lambda, with lambda being the de Broglie wavelength. Waves can have momentum without mass, as they still travel through space and can act on other matter/waves/fields.", "The answer you're looking for is that p=mv is just an approximation for objects that have mass and are moving much slower than the speed of light. The momentum of a photon is actually p=E/c, as described by /u/BlueParrotfish.", "Hi /u/Azooz321! > ELI5: How does light have momentum if photons have no mass? Special relativity tells us that E^(2)=p^(2)c^(2)+m^(2)c^(4) (edit for clarity: here E is Energy, p is momentum, c is the speed of light an m is mass). As photons have zero mass m=0. This leaves E^(2)=p^(2)c^(2) or E=pc. Re-ordering this equation leaves p=E/c. As photons carry energy, they therefore carry momentum. > Momentum is mass times the ~~acceleration~~ velocity (thanks /u/condoriano27) (p=mv), so something with no mass should have zero momentum. This is only true in Newtonian mechanics, which is superseded by relativistic mechanics. In relativistic mechanics, the momentum four-vector is defined as p=(E, px, py, pz), with E being the relativistic energy and (px, py, pz) being the Newtonian three-momentum.", "I would like to add something I think has been overlooked so far. You do NOT require relativity nor quantum mechanics to show that electromagnetic waves carry momentum. Radiation can exert pressure on a surface was known before relativity or quantum mechanics. P = |S|/c can be derived from Maxwell's equations by considering the effect of a charged particle being moved by a passing electromagnetic wave. URL_0", "p=mv is incomplete in the context of special relativity. When the rules of mechanics are re-derived with special relativity in mind, it allows massless objects to have momentum", "Firstly a quick correction: The \"v\" is velocity, not acceleration. Something moving has momentum, whether or not its velocity is changing. Ok, onto the main question: so you've actually picked up on a shortcut we consider in every day life. We often consider momentum to be a function of mass in motion because that's a really handy assumption to make our lives easier. It's easier to teach, learn, and use momentum as the thing describing a physical objects motion. Really, it is actually a function of energy. If something has energy, it can have momentum. You know that famous equation E=mc2, equating energy to mass? Actually that is also a simplification! Turns out there's another thing we add to the mass bit to calculate the energy...and that's momentum (kind of, but that's too complicated for ELI5). Again we typically ignore the momentum bit here because it's not needed for everyday objects that are much slower than light and have mass. For photons the opposite of that is true, they have no mass so we can ignore that part of the equation and instead use the momentum part giving E=pc where p is momentum and c is the speed of light. Now we also know that photons definitely have energy, so thus they have momentum! Bonus: If you're interested in what this momentum is, it's actually related to the frequency (colour) of the light. The energy of light increases as its frequency increases (colour becomes more blue and beyond), thus its momentum also increases! TL;DR: Photons have momentum because they have energy. The more blue...violet... ultra-violet a photon is, the higher its momentum.", "how about this for a 5 year old: \"It's actually not a moving mass that has a momentum, but a moving blob of energy. Mass is just a form of energy so it also has a momentum. Since a photon has energy so it has a momentum.\"", "The most simplified version of this is that the energy of the energy *itself* has momentum. In terms of \"ELI5,\" I think that's the farthest you can really get without simplifying more complex concepts to the point where they are simply wrong. A slightly more complex explanation of this requires the *full* version of Einstein's famous equation. The partial version is most famously E = mc^2. This is true in situations where the frame of reference is a static one. That is to say, it's true when there's no momentum. This is a little over ELI5, but it only requires basic algebra and I hope it's helpful, regardless. If there is momentum, we use the full equation: E^2 = (mc^2 )^2 + (pc)^2 *E* is energy here, *m* is mass, *c* is the speed of light, and *p* is momentum. Below, I'm going to isolate *p* , so that we can see exactly where that is coming from. E^2 = (mc^2 )^2 + (pc)^2 E^2 = (pc)^2 < - mass is zero, so the first bit vanishes instantly (pc)^2 = E^2 < - just flipping it around to get *p* on the left pc = sqrt(E^2 ) < taking the square root of both sides p = E/c < - and finally I'm dividing both sides by *c*, fully isolating *p*. So you can see that the momentum of the 100% massles object comes entirely from its energy. Ultimately, the momentum is the energy divided by the speed of light, which is *huge*. The resulting momentum is so small that it is barely measurable, especially when it's an everyday object, where the momentum from mass is unthinkably larger. But if it's a particle with zero mass, 100% of its momentum is from its energy, and much easier to measure. EDIT: Math formatting", "Everything is made of energy! Energy can have momentum. There is no rule that says only mass can have momentum.", "Because p=mv isn't exactly correct. Think of it as being so close to correct it doesn't matter. Imagine the formula for the difference between p=mv and the real equation were 1/(x+1) [it isn't but let's pretend], where x = mass of an electron. For sufficiently large values of x, y is so close to zero that it becomes unimportant/unmeasurable. I mean, for a baseball the 1/(bajillion+1) term is meaningless. Would you over-complicate the formula by including a term irrelevant to anyone but physicists specifically working on near reletivistic projects?", "For ELI5: Einstein found out that mass and energy are equivalent. If you charge a battery, it gets a teensy bit heavier. If you capture light in a magical box, that box weighs something. Yes, it is more correct to look at the momentum of light and still consider it massless. But it is still a fair intuition to use, to say that light has energy, and therefore mass, and therefore momentum.", "Good question! Let's think of momentum as the idea a moving object has energy it can transfer to another moving object through a collision. For things with mass, one object speeds up and the other slows down after a collision (or their velocities change, to be more accurate). With light, we see that light can hit an object with mass, change its velocity, and the deflected light will be red-shifted (indicating it lost energy). If we look at the system as a whole, the change in the momentum of the deflected object will match the energy lost by the photon. By our momentum definition, that means the photon had momentum and then transferred it to the object! More generally, we can describe momentum due to an objects mass (p = mv) and momentum (energy) due to its wave-character (p = h/lambda or hf/c [since lambda = c/f]). All matter has wave character (as described by its de Broglie wavelength), but for massive objects, the wavelength tends to be so large it's unobservable and the contribution to momentum basically rounds to zero (especially next to the large momentum of an object with mass). Usually we worry about this \"dual character\" with electrons, which have both mass and wave-like characteristics and we need this relativistic explanation of momentum to better understand their behavior. This idea that light has momentum is how solar sails work. Even if individual photons have very, very small momentum compared to a massive object, the sun makes a lot of them and overtime it can push around small objects like probes!" ], "score": [ 2978, 1036, 875, 195, 78, 65, 53, 9, 8, 7, 5, 3 ], "text_urls": [ [], [], [], [ "https://scholar.harvard.edu/files/david-morin/files/waves_electromagnetic.pdf" ], [], [], [], [], [], [], [], [] ] }

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{ "a_id": [ "h3g5int" ], "text": [ "There is a thin membrane between the shell and the albumen (egg white). This membrane is clingy and easily sticks to the white. As the egg gets older this membrane breaks down. Tldr: Don't boil fresh eggs. Use older ones. Edit: Also, peel them ASAP. You want to peel eggs while they're cool enough to handle, but still fairly warm" ], "score": [ 880 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3fxinx" ], "text": [ "Hi /u/DumbBurnerAccount69! > When I say makes up, I have in my mind that protons, neutron, and electrons are all made up of quarks; subatomic particles. According to the [standard model]( URL_1 ), only [hadrons]( URL_3 ) like protons and neutrons are made up of quarks. [Leptons]( URL_4 ), like electrons or muons, [scalar bosons]( URL_0 ), like the higgs boson and [gauge bosons]( URL_2 ), like photons, are elementary particles and are not made up of any substructure. > What makes up a photon? Generally, photons are excitations of the electromagnetic field." ], "score": [ 7 ], "text_urls": [ [ "https://en.wikipedia.org/wiki/Scalar_boson", "https://en.wikipedia.org/wiki/Standard_model", "https://en.wikipedia.org/wiki/Gauge_boson", "https://en.wikipedia.org/wiki/Hadron", "https://en.wikipedia.org/wiki/Lepton" ] ] }

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{ "a_id": [ "h3g7gal" ], "text": [ "So there are microphones on the outside listening to what's around you. Sound waves behave like other waves, if two of equal and opposite size meet, they interfere with each other and cancel each other down to zero. So the software listens to the environment around you, makes a waveform of the sound, and plays it's inverse with the music you're listening to. The inverse waveform \"destroys\" the waveform of the sounds getting to your ear through the headphones." ], "score": [ 11 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3ggcqq", "h3ggmf2" ], "text": [ "We really don't understand aging in trees that well. We think all trees will die eventually, but we don't know for sure what is happening physiologically to them that results in that. Most trees due to accumulative damage to the tree. Most trees only the bark is living, the inside parts are dead and thus can't defend itself from things like pests or fungus. Since it has no defense, damage accumulates over time which will eventually kill the tree", "Well technically nothing dies of old age but they possibly could stop being able to do photosynthesis due to worn roots and will basically stave themselves off their remaining glucose until they die" ], "score": [ 8, 3 ], "text_urls": [ [], [] ] }

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{ "a_id": [ "h3gk0wf", "h3gkp0m", "h3glk0z", "h3gos87" ], "text": [ "An invention like the TV sounds like it had to have been made deliberately, but in reality, for the most part, these things end up with someone wanting to do something, and looking for what parts they know they might need, and only really invent the few bridging pieces, and the specific assembly of pieces. In the case of a TV, for instance, if we have the technology to make an electron-sensitive substance that reacts to having an electron thrown through it, and will react in a different intensity with how many electrons hit it, you then have the basis for a monochromatic image. We already knew that electrons are affected by electromagnets, and we knew how to make a variable strength electromagnet. We just needed a way to spread the particles (electrons) in exactly the right pattern, which is the right invention, and that was nothing more than setting out with a goal, and a lot, A LOT of trial and error. The invention of a TV likely predates what you think of as \"the TV\", though, as a TV is mainly a CRT monitor with an input source that is easy to modulate at will to display a movie or a TV show. EDIT: For whatever reason, I thought it was photons, when I actually knew it was electrons. Replaced every mention of the former by the latter to not be inaccurate.", "The requisite technologies were discovered and demonstrated in the late 1800s. It was then that various scientists discovered the photovoltaic effects of various substances. It was the 1890s that some guy demonstrated focusing and steering electron streams inside vacuum tubes with electromagnets. Early televisions were rather electro-mechanical, and driving a cathode ray tube with a signal was thus invented and possible. But signal storage, like on magnetic tape wouldn't come until the 1970s. It wasn't until the 1920s that someone invented a photo sensor tube that was able to make a television camera, and it wasn't until the late 1940s that someone refined this technology with the idea of reproducing it as an image. Once you have an electrical signal, it's not a leap of logic to beam that over radio as opposed to over a wire, they're practically the same thing, from an engineering perspective. It's a combination of scientists discovering neat properties of materials and properties, and engineers refining these basic principles until they had a handle on something that really demonstrated a utility.", "When people first started experimenting with radiation of subatomic particles they tended to conduct their experiments in vacuum tubes. This is because not only is the subatomic particles unaffected by anything in the tubes but also if anything shows up in this vacuum it must be due to radiation as there is nothing else there. This experimentation lead to the development of both vacuum valves and cathode ray tubes. The first CRTs that were manufactured and sold were for measuring electric and magnetic fields as these would bend the electric ray making visible patterns. And by passing a current through coils mounted on the side of the tube you could measure current directly. Two sets of coils mounted at right angle to each other allowed you to compare two values to each other and make simple oscilloscopes. A tool still used today. From this it was a short leap of imagination to make it show images based on the signals passed to it. It was simply one thing leading to another. The real trick was how to get the audio and eventually the color into the same signals.", "The first TVs were mechanical. A spinning disk was placed behind a screen with holes drilled into it. The screen only showed a small portion of the disk. The holes in the disk moved closer to the center as they traveled along the disk ([like this]( URL_1 )). If you span the disk, you'd see the first hole travel across the top of the screen in a straight line. Then the next hole would travel across the screen just underneath it, so on and so forth until the last hole crosses the very bottom of the screen. After that, the process would repeat again with the first hole traveling back across the top of the screen. If you place a light behind the disk, you'll see that part of the screen light up. Spin the disk fast enough and the whole screen appears to be permanently lit up due to an optical illusion called permanence of vision. Basically, your brain hangs onto an image for a brief time after it disappears. By varying the intensity of the light as the hotels travel across the screen you can make a black and white image. Now you just need to sync up a recorder disk in the studio with a TV and you've got a transmitter reciever. This system is called a Nipkow disk. [Here's]( URL_0 ) a very primitive one in operation. Unfortunately, this device had huge limitations. The screen was tiny, and the disk was very large. A modern size TV would require a disk the size of a building spinning at thousands of RPM to maintain the illusion of a single moving image. To get around this limitation, the disk was replaced with a spinning cylinder and the projector placed inside the tube. This allowed screens to get much larger, and the holes could be smaller and closer together, increasing the lines of resolution. Syncing auto to the visuals wasn't much of an issue because all TV was broadcast live in the early days. Pre-recorded TV shows didn't become common until the 50s when the videotape was invented. Later, the mechanical TV was replaced by the cathode ray tube (CRT). CRT creates an electron beam inside a vacuum tube. A magnet can be used to bend that beam as it's transmitted to the screen. Just like a mechanical TV, it draws lines from left to right down the screen. Finally, the CRT was replaced by digital TV. The TV signal is now sent as a data packet. It contains instructions for the color and intensity of each pixel for every frame of the footage, which is decoded by a chip in the TV. --- But none of this came about as a single invention. It's not like someone sat down one day and decided to build a TV from scratch. It was the culmination of several different inventions being put together in new ways." ], "score": [ 10, 3, 3, 3 ], "text_urls": [ [], [], [], [ "https://1.bp.blogspot.com/-bCLSLBsXcZ0/WPXEe-kVY7I/AAAAAAAAScs/hmqiWLhUvI4TI0kb0D0hCZggiyOpTNe4ACLcB/s1600/Working-tv.gif", "http://www.earlytelevision.org/Yanczer/images/60_l_lens-2.jpg" ] ] }

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{ "a_id": [ "h3guqmg", "h3guwur" ], "text": [ "Usually, big companies will go to design studios, and they’ll pay a lot of money for their branding. The branding consists of more than just a logo, it involves strategy, voice and writing, assets like fonts and patterns, and sometimes social media guidance or websites. A design student could make a logo, sure, but they don’t have the experience needed to understand the industry, avoid lookalikes, and create a unique experience for the company’s target audience. Not branding, but here’s an example: the Wendy’s Twitter strategy, which is being copied in a lot of fast food companies now, was brainstormed and carried out by VMLY & R, a megastudio who spends lots of money to hire geniuses that come up with truly memorable experiences.", "Logos may be simple pen strokes but it’s the “identity” that designers create for a brand/person. Marketing also has lots to do with the creation of a logo. It’s the collaboration of both that make it successful." ], "score": [ 11, 5 ], "text_urls": [ [], [] ] }

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{ "a_id": [ "h3h5tlq", "h3h6im4" ], "text": [ "You can think of photons as like little packets of waves, while they act like particles they still have a frequency and wavelength. Each individual photon carries this frequency information, and the energy of the photon depends on what the frequency is.", "Your eyes have four different light detector cells. One type, the “rods” react to all incoming light and report the total light intensity to your brain. The other three are “cones” and react only to specific wavelengths of light. They peak at 445, 535, and 575nm. Your brain combines the intensity signal from the rods with the wavelength range measurements from the cones to assign color to the light that’s hitting your eye. Photons have different wavelengths because they can carry different energy. They all move at the same speed so to carry more energy they must oscillate faster. This faster oscillation means a shorter wavelength, and higher energy. Visible light has wavelengths in the hundreds of nanometers. Low energy light can have wavelengths many meters long and high energy light can be less than one nanometer." ], "score": [ 6, 3 ], "text_urls": [ [], [] ] }

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{ "a_id": [ "h3h6uzm", "h3h7f0g", "h3h7arn", "h3h7qjq" ], "text": [ "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.", "Well, that's kind of the definition of a staple food/crop. Food that is eaten in such quantity that it provides the majority of the caloric energy and nutrients for a given people. Starchy foods such and grains and legumes contain high amounts of carbohydrates, making them primary sources of energy. The fact that they can be grown densely makes them even more attractive from a primary food source point of view. I realize it's a book/movie, but take *The Martian* as an example, as the author did the actual real-world calculations to figure out how much would be needed. Mark Watney is able to grow enough potatoes to support his caloric needs for a few years in a single room of the hab structure that housed the astronauts.", "These crops become staples for several reasons. Usually it is because they grow easily in whatever climate they are most common to. They are calorie and nutrient dense. They also store for long periods of time making them a reliable source of food when we hadn't yet developed preservation tools and methods. The result was a region that incorporated this resource in many dishes to create variety.", "Because agriculture began when humans figured they can grow plants that can provide them with food. And the plants they could grow the easiest in various places where it arose (Egypt, Mesopotamia, Indian subcontinent and valleys of the great rivers of China and later in Mesoamerica) turned out to be grasses with edible seeds. Those grasses were selectively bred to increase the production of seeds (because that was the most energy rich part of the plant) into the variants known as staple crops today" ], "score": [ 29, 17, 9, 3 ], "text_urls": [ [], [], [], [] ] }

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{ "a_id": [ "h3h89db" ], "text": [ "You know the thing that scientists tend to yap on about regarding some sort of global climate change. It turns out that heating the planet up just a couple of degrees causes things like jet winds to move around like crazy. Events that previously were rare like polar winds getting all the way down to Texas or tropical winds getting all the way to Canada is now pretty much standard weather patterns we expect every year. The jet winds used to be pretty stable and separated the climate in North America between cold north and hot south with only some seasonal deviation. But it is now moving a lot further north and south then it used to." ], "score": [ 5 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3hs45l", "h3hdoqf", "h3hphac", "h3hsqj0", "h3j6nty" ], "text": [ "This is probably the biggest problem that thousands of engineers have been working on the last few decades, with the resulting improvement from GSM connections to incredibly slow internet, to 1GBps on 5G. There are lots of different ways each receiver can differentiate which signals are meant for it. 0. Spatial sharing. Wireless signals have a limited range so each device only communicates with the tower that is closest to it. The area around each tower is called a \"cell\", which is why we sometimes call mobile phones \"cellphones\". (The edges where two cells overlap get tricky.) 1. Time Division Multiple Access, TDMA. Basically each transmitter takes turns. 2. Frequency Division Multiple Access, FDMA. The electromagnetic spectrum can be divided into lots of little \"bands\". An electronic circuit can listen to one band at a time, and filter out all the others. 3. Code Division Multiple Access, CDMA. I don't know an ELI5 explanation for this. An analogy is standing in a crowded room where different people are talking, and your brain can consciously tune into one person or another. 4. Directional antennae. A big advance with LTE and 5G was antennae which can direct their signals more precisely. Now two devices relatively nearby can transmit/receive at the same time, at the same frequency, with the same code, and still get their message through. 5. Non-orthogonal multiple access, NOMA. Because amplitude decays as you get further from the transmitter, you can have a large amplitude signal and a small signal sent at the same time. The closer receiver subtracts off the large signal and uses the small signal. The further receiver won't even detect the small signal and uses the large signal.", "There are two main techniques. The first one is Time-Division Multiple Access which basically means that the time is split into different segments and each phone gets its segment to listen or transmit as assigned by the cell tower. The second technique is Frequency-Division Multiple Access where every phone is given its own frequency to listen and transmit on. Both of these are used in combination. So your phone gets its own time and frequency slots that it can use. In addition there are some slots where all phones are requested to listen inn on which allows the cell tower to give specific messages to phones when there are updates in the situation. It does not make sense for completely idle phones to get their own slot when there are no traffic. Each phone have its own IMSI code which helps the cell tower identify each of them when sending or transmitting data.", "So back in the day with landlines sometimes the phones would interfere and you would hear someone elses call for a moment. How did that work?", "eli5, think of it as your signal has the right color. it is all just photons, so if instead of a cell phone, what if you grabbed a flashlight and hung your hand out the window. you could flash it on and off to send your signal. up on the tower, there is a guy watching and he passes your signal onto a landline. he has his own light up there, but instead of a flashlight it is a flood light and he uses that to send your message back. you know which message is yours by the color. in the real world, it is frequency, not wavelength, and they also use very accurate clocks to send messages in sequence with everybody knowing their own time block. sometimes there is interference, back when i was a kid, they use to put signs on buildings warning people with pacemakers that there were microwaves in the building, but usually things are planned better.", "Most people are providing answers for the \"how does it not interfere\" and those are good answers, though I think we can ELI5 further by just saying that for any given area there are ways to slice up the whole cell's capacity such that each phone that needs to receive a call or data can do so in a very prescribed pattern that it can learn about when it's told that new data is about to be sent to it. And it knows that it's about to be sent data in that way because when it's not receiving some data, it's hanging out listening for the tower announce it has data for that specific phone (not quite using their phone number but close enough). Think of it like a huge room of people with unique names all sitting there silently and some announcer is constantly shouting \"Jim, go into room 45-A for your call in 2 seconds. Mary, go into 87-X for data in 2 seconds.\" And then only they have the key to that room (too complicated to ELI5 how the keys work) so they go there and listen to whatever the message is. Sending data works basically the same way except Jim's twin John goes to another big room with all the other phone-people and shouts that he wants to send data in 2 seconds and waits to hear the announcer tell him what room to go to for that. Sometimes two people shout at the same time and the tower dude can't hear either, so they both have to shout again to try again. Jim and John are different people here because receiving and sending data are different activities but they're twins because they're very related (haha!) In the same device. ETA: on the interference point, you might find it interesting to think about how all of what I said basically relies on everyone playing nicely and following the rules. If someone with an airhorn were to go into either of the big rooms and blast everyone, or even outside each of the small rooms, then nobody would be able to hear anything. That's what jamming equipment does intentionally, and that's why it's illegal. And as for unintentionally interfering, that's why every device sold in the US has an FCC sticker that certifies the device has been tested and it will follow all the rules." ], "score": [ 68, 35, 3, 3, 3 ], "text_urls": [ [], [], [], [], [] ] }

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{ "a_id": [ "h3hfbf8" ], "text": [ "Inflation is still not totally understood by economists, and there is a ton more research to do but here is the ELI5. Over time, the world makes more and more money from people going to work (in reality money creation is made from debt but idk if a 5 yr old is ready for that). That money is going to be used to buy stuff, but because there is more money out there and people want to go out and buy stuff with that money (monetary velocity) the prices of things will go up over time. This increase in price is called inflation. Deflation, the opposite can happen from two things therefore. 1. Decrease in supply of money, people have fewer jobs see 08, great depression, etc. 2. Decrease in how much people go out and buy stuff, see covid. Aka decrease in monetary velocity." ], "score": [ 3 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3hfv2y", "h3hgbyx" ], "text": [ "When you have the HD movie coming your way, you aren't able to detect the latency, being the time it takes for the signal to travel from the ground to space and back down to you. You just detect the incoming stream, and show it as it flows in, like if you were dangling your feet in the water looking at the river, and have no idea how long it took to flow down from the mountains (or to fall on the mountain as rain after evaporating from the ocean, but the analogy is deep enough already). If you try to do something on satellite that depends on 2 way communication, then the delay becomes obvious, AND it doubles, cause anything you send to them is delayed (like when you click on a link) as it goes from you to space and back down to them, then the response also has to go from them to space and back down to you. It makes clicking webpages slow, and real time games unplayable.", "The problem is the directionality. Yes, both use packet based internet protocols, but streaming essentially just sends you a stream of packets in order - if you miss a few well, thats too bad - but the streaming protocols are designed to be able to handle gaps of missing information (maybe you'll see a few seconds of garbled image and audio but then it recovers). There's also the concept of buffering and caching for streaming media, so if you pause your playback the content is still streaming in from the originator. In all of this, your client may send an occaisional keepalive (\"are you still there? should I keep sending you stuff?\") but other than that its one way only: from the server to your client. For non streaming internet usage, its really a two way affair. Your client says \"give me < this thing > \", the server says \"ok here's the first bit let me know you got it\" \"got it\" \"here's part two\", and so on and so on. The problem is satellite transmission delay. When your client sends the first \"give me this video\" msg, thats got to go up to the satellite, then back down to earth somewhere and THEN through some part of the internet. And the ground to satellite or satellite part is the killer: its about 120 ms every time you make that hop. So for the first message \"give me this video\", we're talking: you to satellite (120ms), satellite to ground (+120ms), some internet (~40-50ms), some processing on the server (40-50ms), more internet (50ms), then two more satellite hops: +240 ms. Add all this up you're talking upwards of 6-700 ms, or almost a second. Which is _glacial_ at the speeds computers run at. Meanwhile your client browser or your phone or whatever is sitting there twiddling its digital thumbs. Compound this by x10 since every web page you request is actually hitting a dozen seperate webservers (you know the ones that feed you ads), so all of these requests have to trickle in over several seconds before your browser or phone can even begin to start to render the page." ], "score": [ 6, 6 ], "text_urls": [ [], [] ] }

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{ "a_id": [ "h3hqkty" ], "text": [ "Ok. The actual answer is, \"We don't know. It's still one of those mysteries.\" There are ideas on what might be happening. It may be pain from muscles in the shoulders, neck and head. It may be caused by dilating blood vessels in the head. It may be caused by the membrane around the brain becoming sensitive to pain. Nerves in the face may just start signalling pain for no good reason. In a migraine the headache may be caused by overacting brain cells causing the release of serotonin and/or estrogen which causes blood vessels to constrict. I don't think it's entirely sure how this would cause a headache in a migraine sufferer but would explain why more females get migraines than males." ], "score": [ 26 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3ivg93" ], "text": [ "There are four primary approaches to making a non-alcoholic beer. Wine may undergo similar processes, though my experience is that many NA wines are just verjus. Dealcoholization — Full-strength beer is produced, and then the alcohol is removed and replaced with water. This can be done through steam distillation, vacuum distillation, stripping (using water vapor or nitrogen in a special way to filter out the alcohol), or reverse osmosis. Limited fermentation — a fermentation process where sugar is only minimally converted to alcohol, whether by limiting fermentable sugar or by using yeast strains that only ferment certain types of sugar; stopping a regular fermentation early is an approach that yields sweeter beers and generally is a more old-school way of doing it Dilution — making a concentrated version of a beer that is high in flavor with the usual amount of alcohol and then diluting with water to reduce ABV and bring the potency of the flavor to a normal level Unfermented — Force-carbonated with CO2 and flavored to taste like beer" ], "score": [ 7 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3hx6zg" ], "text": [ "Death Valley is a valley, not a flat region of sand. This traps air and greatly reduces surface winds at high temps. No wind allows temps to get even hotter." ], "score": [ 80 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3i37bj" ], "text": [ "i have been getting four or five of these a week for a year and a half now. i have blocked hundreds of numbers. i can't wait until they bust these guys" ], "score": [ 3 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3i9xa6", "h3ja900" ], "text": [ "The forces involved inside an MRI machine are \\*enormous\\*. Part of the MRI scanner is a ludicrously powerful magnet, and another part creates a very rapidly changing electromagnetic field...the combination causes enormous forces & stress on the coils inside, causing them to expand and contract and make the \"banging\" noise we associate with MRIs. The only way to stop it would be to somehow hold the coils so tightly that can't move \\*at all\\*. And the forces are too large for that to be practical. And if the forces weren't so large, the MRI wouldn't work. It's kind of like asking why we can't make a quiet jet engine...we can make it quietER, but it's inherent to the machine that you're going to blow thousands of pounds of air through it at nearly Mach 1 and that just can't be silent. MRI is the electromagnetic version.", "They are pretty quiet, I usually fall asleep inside of them. Am I the only one one thinking that the sounds they make is nice and somewhat meditative?" ], "score": [ 115, 8 ], "text_urls": [ [], [] ] }

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{ "a_id": [ "h3i3ukc" ], "text": [ "Whoever is directing the animation chooses people to write music, create sound effects, and of course voice characters. This is generally done in a series of meetings very early on in the process. Voice acting happens before the animators start key framing in most cases, and sound effects + music are added once key framing is done. Once the key frames and full audio are in place the animation studio can make sure there are no mistakes and then proceeds to finish the episode." ], "score": [ 3 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3i4l66" ], "text": [ "The surface of the speaker that you see, if you take the mesh cover off, is what is physically making the sound. A coil and magnets push the front of the speaker back and forth and that creates sound waves you can hear. Picture your hand in the water and you push it forward and waves come from your hand." ], "score": [ 4 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3i52yg", "h3i562k" ], "text": [ "They have so much power because the homeowners agreed to it when they bought the house. You are not forced or required to buy a home that is part of an HOA it is a choice. My own home is private.", "When you buy or rent a house from a new development that has a Homeowners Association attached to it, you first must sign a contract stating that you agree to follow their rules. If you don't sign that contract, you can't buy or rent that house. The other important thing to note is that many people have perfectly fine dealings with their HOAs. But no one goes online to say \"They sent me a polite reminder to trim my yard\" or \"They hired a landscaper to make our corner park look nice.\" As such, you only hear about the extreme worst case scenarios, which can give you a skewed idea of how bad HOAs are in general." ], "score": [ 3, 3 ], "text_urls": [ [], [] ] }

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{ "a_id": [ "h3ik46x", "h3ikc6f" ], "text": [ "poetry is a genre of literary work: you cannot “poetry” in the same way you can “sing” or “dance”. Poems can be spoken (take any recitation as an example of that) or sung (most songs by Schubert and the like). Singing and rapping are both forms of musical delivery. Rap emphasizes rhythm + cadence, and is spoken, whereas singing focuses on musical notes and is, well, sung. Now spoken-word poetry, in my experience, is more free-tempo than rap, although it still focuses on your delivery and rhythm.", "I would say, first of all, that they have a lot of common threads. All three attempt to use words in an unusually concentrated and evocative way in order to move and engage the listener in ways that ordinary daily speech does not. For all three, rhythm is fundamental and crafted to pull in the listener and hold attention. In all three, certain striking verbal arrangements are deployed, such as rhyme, near-rhyme, words with sounds that echo one another, metaphor, and imagery (words that aim to create a mental visual picture). There is often a refrain, a phrase repeated throughout the piece to emphasize the kernel of the message. Song most often adds a melody and harmonies that may evoke and reinforce the message of the piece. Rap also uses melody, but usually less than other song forms, and it leans heavily on rhythm and repetitive sounds to power the message. Poetry often uses the same techniques of sound repetition and rhythm, but in a form meant to be read, either silently or aloud, but usually without obvious melody. So in fact these three techniques have a lot in common, and sometimes they borrow techniques from one another. And they all use various tricks of sound and word play to make them engaging and memorable." ], "score": [ 14, 3 ], "text_urls": [ [], [] ] }

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{ "a_id": [ "h3ig4vy", "h3ihpcz", "h3ik2yh" ], "text": [ "The heating element is in much better contact with the water than in a pot on the stove. The pot sits on a rack suspended above a burner, or touching part of the heating coil. That's much less efficient than having the water directly in contact with the source of heat.", "The heating element in the water makes a huge difference, but so does containing the heat within the boiler. Heat escapes from a pot on the stove. Water in a pressure cooker boils much faster, because the heat doesn’t escape.", "Not only is the heating element in direct contact with the water, the pot in which the water sits is insulated from the surroundings. That means there is less heat leaving the water as the boiling takes place. This results in a faster boil time." ], "score": [ 33, 10, 3 ], "text_urls": [ [], [], [] ] }

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{ "a_id": [ "h3ip9jb" ], "text": [ "Answer: Heat lightning isn't actually a thing. Its just caused by distant thunderstorms that are too far away to hear the thunder. Source - Spent most of my life believing it was a thing until a local weatherman corrected me on a field trip" ], "score": [ 10 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3ir87j" ], "text": [ "Same reason the sun turns red as its setting. Near the horizon, light from space has to go through a lot more atmosphere to get to you. The atmosphere is better at scattering short wavelength light than long wavelength. You can kind of think of short wavelength lights (having more peaks and troughs) as bouncing off of more atoms because it's so wavy, if you'd like. Meanwhile, long wavelength can weave between them better. (This is **not at all** how it actually works, but it helps me visualize it). Anyway, light from the sun (and reflected light from the sun from Venus) is white light, made up of a bunch of wavelengths. The shorter wavelengths, like blue, get scattered around, largely back into space. The longer wavelengths, like red, get through all of that extra atmosphere and into your eye." ], "score": [ 5 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3itssd", "h3ivni6", "h3it1lb", "h3iurra", "h3iuhnj", "h3iwr8o", "h3j1udh" ], "text": [ "Research shows that if you smoke marijuana with higher concentrations of THC (the chemical that makes you high) it can stimulate the amygdala or \"fear center\" of your brain. So anything that increases your dose of THC, like a really strong bud or something like a strong edible, can cause those feelings.", "I have this exact problem. Here’s what helps me, CBD helps with bringing you down. To avoid, use a lower THC concentration and vape at a low temperature (I use 325). The legal stuff is very potent, start with one or two hits. If the panic attacks continue even when doing those things, you might have to quit. I couldn’t for about 10 years. Now I don’t panic (because of the techniques) but can’t use because of bipolar, it sends me into mania. As mentioned itt, I’d avoid edibles. I don’t trust them because absorption can be unpredictable.", "Your smoking to much, as in the amount you inhale, smoke less and possibly change the strain your smoking", "Are there any other common factors in your panic attacks? A specific situation, place, or person? It could be that the weed is lowering your defences to the point where another latent problem is pushing its way thru your psyche.", "You don’t have to smoke a full doob the the dome. Take a couple puffs and do it with people you actually like and respect. Or do it by yourself. Slow down and relax.", "I never had a panic attack when stoned but i do get vertigo from time 2 time while stoned. What sucks is i usually have a 30second window that i feel before i lose conciousness to sit down or lay down so dont fall and hurt myself badly. But for others who are there who witness this event happening they all say i had a seizure like reaction and goto hospital to have them do testing to see and always comes back negative for seizures. My doctor explains it to me as my body nerve center dectects sumthing is wrong and doesnt know why so brain hits a restart button(thats when i lose conciousness)and comeback to 5-20secs later(dont know exact time im out for and my friends always panic so they dont know how long either). But he tells me to not worry about it(if a year or two between events) unless happens frequently(2or more events in a year).", "I've seen this happen to people a few times There's no good answer other than \"that's just one of the effects of the drug\" You experience symptoms of being high, you misinterpret those symptoms because you are high, there's a feedback loop where the experience makes them worse and them getting worse creates a worse experience which goes around and around and around, and you either try to interrupt the thoughts and relax, or you need medical help to get through it You can't make it pass faster because you need the drug to leave your body since interrupting your thoughts is impossible/difficult to do while high, and if you find yourself here you have pretty much no choice but to ride it out (with or without medical help) until it leaves your body, at which time you should seriously consider whether you should be smoking it to begin with since not getting high is how you avoid it. If panic attacks are happening while sober visit your GP, if you visit your GP because it's happening while you are high or in between bouts of getting high - they will tell you to stop getting high" ], "score": [ 43, 10, 9, 5, 4, 3, 3 ], "text_urls": [ [], [], [], [], [], [], [] ] }

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{ "a_id": [ "h3ivzsc", "h3j5qhr", "h3iwt7h" ], "text": [ "When it comes to physics, you can only feel acceleration, not motion. The earth is moving at a constant speed, there for we cannot feel it as we are not accelerating nor decelerating.", "Saying that something is moving fast does not really mean anything. You need to compare it to something. You and a friend are sitting in a train, and your friend goes up and walks a normal pace to the toilet. To you it looks like the friend is moving at a slow pace. To someone outside of the train it looks like that friend is rushing past them at 200km/h. Why is this? Its because its relative. It depends on what you compare it to. The train is moving at 200km/h **compared** to the ground. But since you are also sitting on the train, you too are moving at 200km/h **compared** to the ground. But **compared** to the train, you are moving at 0km/h. So when your friend goes up to walk to the toilet that friend is now moving at maybe 1km/h **compared** to you, but compared to the ground that friend is now moving at 201km/h. So this is the reason we cant feel the earth moving. Compared to the Sun the earth is moving at 30km/s. But compared to the sun we are also moving at 30km/s, So compared to the earth we are moving at 0km/s. From our point of view the earth is standing still.", "Imagine your in a car, you get pushed back into the seat, but once you get to speed and maintain it, you don’t feel anything. You feel yourself going 0-100, but you can’t feel 100-100, it’s the acceleration that’s noticeable not the speed. Things on earth are travelling the same speed as earth, and gravity counteracts the centripetal force" ], "score": [ 15, 11, 4 ], "text_urls": [ [], [], [] ] }

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{ "a_id": [ "h3iys4i" ], "text": [ "Lactic acid is formed when your body doesn't have enough oxygen to create energy by normal means. If I'm walking down the street, my muscles are receiving oxygen and I'm not using them that hard. This allows my body to break down my food using oxygen as it normally does. If I start sprinting, my breathing can't add enough oxygen for my muscles; this means that they can't break down enough food to fuel my muscles. To compensate, they use a process called lactic acid fermentation to break down my food without oxygen. This gives my muscles enough fuel to keep up with my vigorous exercise, but it also produces a byproduct called lactic acid. Lactic acid is a necessary compromise the body makes to try and keep up with difficult exercise; however, it isn't good for your body. It's meant not as a regular thing but more as a \"in case of emergency\" tool to compensate for the relative lack of oxygen." ], "score": [ 8 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3j8w2u" ], "text": [ "This is a hard one to eli5, but I'll try. Living cells generate some really cool, really large, and really complex molecules and we've been playing around with them for a long time now. We learned that a certain combination of molecules can lock together when thoroughly mixed, like epoxy glue. Think like the actual shape of the molecules fit well in a pattern, like puzzle pieces but there are magnets that guide them to lock together correctly when the box is shaken up. After a lot of testing, we figured out a few molecules that would combine, but only when we heated them up first because one of the molecules was crimped and curled and had to be unfurled first - heat does that to a lot of larger molecules, it's also why a lot of fats are liquid when warned up. But then we figured out that we could heat ONLY those molecules if we shined a very specific light on them. Different molecules react differently when struck with light of varying wavelengths - that's why things are different colors. That same property allows these molecules get unfurled when energized (heated) by the light of that specific wavelength, which allows them to lock with the other kind of molecule they're mixed with." ], "score": [ 12 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3juoly" ], "text": [ "Doesn’t fire mean to cook it and to go is pack it to go?" ], "score": [ 7 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3k1l1o", "h3kgs86", "h3k0q9t", "h3kwu82", "h3k5rc8", "h3kxhyr", "h3k20v6", "h3lda5p", "h3lc2dy", "h3leyv2", "h3k3wxx", "h3luhv9", "h3kl85g", "h3lj25k", "h3l3d38", "h3lxrtr", "h3lhc0p" ], "text": [ "CO2 is a very low-energy molecule. In order to break it apart, you need to add energy to it. Plants do this using sunlight as an energy source for photosynthesis, turning CO2 and water into sugar. Whenever we eat the products of those plants, we eventually reverse that process, turning the sugar into CO2, water, and energy. The real problem with our greenhouse gases is that normally that cycle of plants taking in CO2, plants being eaten, and then animals exhaling CO2 is a closed cycle. The amount of Carbon between the atmosphere, plants, and mammals remains pretty constant. However, millions of years ago, there were some trees that didn't get eaten by bacteria when they died (there just wasn't a bacteria that could eat them yet back then). This resulted in a lot of dead trees capturing carbon outside of the natural cycle. Those trees eventually got buried underground as the Earth shifted around, and over millions of years have broken down, and are now what we call fossil fuels. Whenever we burn fossil fuels, we reintroduce that carbon into the cycle. Without more plants or animals for the carbon to live in, all that extra carbon in the cycle ends up in the atmosphere.", "Your question assumes that we can’t, but we actually can convert carbon dioxide, methane, and some of the other greenhouse gases. The main limitation to that strategy is that capturing them from the atmosphere is challenging.", "We can. Trees convert CO2 which is a greenhouse gas into carbon and O2 which isn't. As long as we plant more trees and don't then burn them (which creates CO2 again) we're winning.", "one extra note, there are many project in the works to capture carbon from the atmosphere and sequester it somewhere. its much easier to do it you get it at the source before its diluted, so power plants and the like are ripe for this. but there are several large scale projects ongoing. I dont know the details of how they work or what they products, I want to say calcium carbonate is one of their products... it does take energy, but if you get that energy from nuclear or a renewable source, its a net reduction. That is likely where we will end up, we've already released too much, and it appears inevitable that we will (or already have) reach the point of runaway change, so it will take an active effort to dial it back. itll just cost us a good bit more to do so.", "There essentially aren't any gases we can convert the CO2 into; the long and short of it is that *all* gaseous molecules that have more than two atoms will be GHGs in the atmosphere. All you can nominally do is convert the CO2 into O2, but then you have to figure out a way to store all of that carbon. Further; CO2 is actually the preferred GHG as it's considerably weaker than a lot of the alternatives. If you're in any situation where you basically take it as a given that you'll be emitting GHGs into the atmosphere, you deliberately convert as much of it as possible to CO2 (hence why there are gas flares on oil and natural gas wells; flaring off the escaping gas burns it and converts it to CO2, which is both cleaner and safer for the environment).", "We burn fossil fuel and create CO2 to get energy. To revere the effect of CO2 would take more energy then we got by making it to begin with. Spending energy changing green house gasses don't make sense until we no longer use fossil fuel at all since if it worth it to change it then it is even more worth it to not create it to begin with.", "Yes, but that costs money and takes energy. If we make the energy by burning coal and producing more CO2, that's not a good thing. If we make the energy with a carbon-free solar or nuclear source, that would be fine except for the cost. Who wants to pay more to reduce the greenhouse gas level in the atmosphere? Nobody.", "To convert CO2 into something else, you would have to add energy into the chemical reaction. And since the whole reason we burn fuel to create CO2 is to get energy *out*, we'd be burning fuel to make CO2 and energy and then turning them back into fuel. We'd be better off just not burning fuels in the first place.", "Lots of answers in here, but the real ELI5 answer is that we do. In fact, most of the carbon credits in the US are generated from projects that do exactly what OP is asking. They generally take refrigerants (like the stuff in your car air conditioner). By burning it, and converting the gas into mostly CO2, it changes the impact from thousands into single digits - on a per weight basis.", "It can be done. Trees do this every day. The catch is that it's very energy intensive... which is the whole reason we've released so much into the atmosphere to begin with. (utilizing energy from chemical reactions which have an exhaust product of co2). So there's kind of a catch 22 there.", "One aspect to point out is that the problem isn't that greenhouse gases exist, they do. There is a lot of CO2 in the atmosphere and always has been (we need it in the atmosphere). There is lots of water vapor as well - we need it too. There is methane. The problem is that we are increasing those levels. We are changing it (very very rapidly on the scales that atmospheres change), that's the problem. We change those levels, and the atmosphere directly changes as a result. Also, CO2 lasts a very long time in the atmosphere, the CO2 your car spews out today will be in the atmosphere for ~100 years. So it keeps building up, it keeps increasing. A combination of reducing emissions, along with removing CO2 from the atmosphere (which is very expensive and for all intents and purposes not done on a meaningful scale) can solve the problem.", "ELI5: Imagine standing on a mountain and throwing rocks down the valley. The rocks break into small pieces that spread everywhere. Now the rocks are fuels, throwing them are like burning fuels and the resulting pieces that spread everywhere are CO2. So to take CO2 to turn it into something else would not be impossible, but very tedious and difficult, just like collecting the small pieces of rocks and try to stick them back together. Now I know that there are a variety of greenhouse gases that get created by different processes, the main culprit of global warming is CO2 so I will only consider CO2 for the sake of simplicity in my answer. ELI20: We can and we are trying to capture and store/convert CO2. There are several challenges to overcome though: • Capturing CO2 from the atmosphere is very energy-intensive. As everything always wants to spread out and mix together, to separate CO2 from the air (there are only around 400 molecules of CO2 in 1 million air molecules) requires a lot of energy, and this energy should not come from fossil fuels, or we are going to release more CO2 in the atmosphere than we capture. So it is much more efficient if we can capture these guys right at the source before it spreads out. • But even trapping CO2 right at the sources, after that if we are just going to store them somewhere, then this process will always be more expensive than just releasing everything to the atmosphere. So unless all governments have policies that force/incentivize every major emitters to store their emitted CO2, capturing and storing it are not really economically viable options. And to get all governments to agree to do something good, well good luck then… • This leaves us with another option, which I think is the most viable, is to capture CO2 at the source and try to turn it into something with added value. Turn out CO2 can be turned into a lot of high value carbon-based chemicals like alcohols, or ethylene (to make plastic). But since CO2 is very inert, turning it into something else, again, requires a lot of energy. One strategy is to take excess renewable energy (when the sun is shining on solar panels at noon) and turn CO2 into products that can store this energy, like ethanol, then when energy is needed and there’s not enough renewable energy (when it’s raining on solar panels), we can turn these products back to CO2, generating energy. So actually, there is a very active scientific field of trying to convert CO2 into added-value chemical more efficiently. Scientists are making a lot of progress in making this process more economically-viable. Hope this helps.", "We can convert CO2 into O2, which is ozone, which is also toxic. Sure, the ozone layer, way high up in the atmosphere, where it's safely the fuck away from all living things, helps block UV light by absorbing it, and there are natural processes that produce ozone, like lightning. But if we had an ozone plant, you would want no living thing anywhere near it. Oxygen has almost no interest bonding with other oxygen molecules. Oxygen is actually one of the most reactive elements in the universe (perhaps second or third to carbon, then possibly hydrogen). And most of Earth's oxygen is actually locked up in the crust in the form of metal oxides. You can buy ozone generators, that are essentially tiny little spark plugs off the tip of a needle. These make ozone from existing oxygen in the atmosphere, and they exist largely for exposing clothing, carpet, and car interiors to eliminate odors. Car detailers will set these things up in a closed car OUTSIDE, so any ozone that does vent won't be in their garages, where people are. To convert CO2 into O2 is an energy intensive process. CO2 is very stable, so you need to spend energy to break the bonds. It's why CO2 is a waste product and not an energy source. Hydrocarbons, like gasoline, are large and unstable. Provided an abundance of free oxygen atoms to react with, like in our atmosphere, we can get an exothermic reaction, more energy out than we've had to put in. But that aside, how do we do this on a planetary scale? Most of our energy comes from burning coal or natural gas, and there's always loss in a system. So we'll actually produce more CO2 by burning fossil fuels in order to generate the electricity needed to break CO2 bonds, which as you can imagine, has its own inefficiencies. Should we go nuclear, since that's a green energy (as nuclear produces no CO2 emissions)? We would be better served building more nuclear plants and shutting down the coal and gas plants, than trying to convert CO2. And how do we gather all the CO2? An air pump will have only a regional effect. Especially if it were efficient, it would end up sucking in it's own clean exhaust, thus reducing it's efficiency. You'd only be able to hope that the wind is blowing in a consistent direction. And how big do you build this thing? The atmosphere is big, and we can only capture the air that passes the station. Even an inlet several hundred feet across is small compared to the total surface area of the Earth and the volume of the atmosphere. And even then, you're only capturing CO2 that's close to the ground. Unfortunately, we're basically fucked. The best chance we have is to reduce the amount we as a planet-wide civilization produce, and empower the planet to consume the CO2 itself with the free energy it gets from the sun. The side of the planet facing the sun at any given moment is a larger solar collector than we'll ever build, which it's size vastly outstrips any inefficiency nature has in converting sunlight into captured CO2. And it's not the plants on the surface that to the vast majority of carbon sequestration; hell, the Amazon - \"THE LUNGS OF THE EARTH\" as it was called and was always an exaggeration, was just barely more than carbon neutral for most of its existence (because there's enough plant decay to almost completely offset it's consumption), and it wasn't until we cut nearly the entire thing down already that it now produces more CO2 than it consumes. No, most of the Earth's CO2 sequestration comes from the ocean. Water naturally captures and holds in solution CO2, and the Earth's surface - I don't know if you've noticed, but it's mostly water. I'm feeling snarky.. It's why ocean acidification is a big fucking deal. Because as soon as you dissolve CO2 in water, you have carbonic acid. It's killing the oceans, especially coral reefs and the habitats the rest of ocean life depends on. Eventually everything is going to die and we're going to be left with nothing but squid and algae blooms. So what happens to the carbon once it gets into the oceans? Well, some of it is reduced by chemical reactions. Most of it is captured by algae, which dies and precipitates to the ocean floor. Some asshole a few years ago illegally dumped a bunch of iron into the Pacific off the coast of Canada, thinking he was saving the planet. He converted a bunch of CO2 alright, but created a dead zone in the ocean a few thousand miles wide for a few weeks. Algae bloom. No oxygen. Everything suffocated, even the algae. As you can see, it's a big, complex problem.", "You can, that's what carbon capture is. Transform CO2 either into carbon and O2 or some other carbon containing solid. It's just REALLY difficult because CO2 is very stable. All other greenhouse gases will decompose to something else, ex. methane decomposing to CO2. That's why everyone is worrying mostly about CO2 itself or CO2-equivalent of other gasses.", "We can. URL_0 . It's mostly done with point sources, but we've had CO2 scrubbers since the 60's, maybe earlier. They were used in the Apollo missions to keep the astronauts from asphyxiating on their own emitted carbon dioxide. The question is, how much energy and money does it cost, and who's going to pay it. But I would argue that simply taxing hydrocarbons and other carbon-generating industries (like concrete and steel making) and using the funds to build solar or wind-powered scrubber plants. Such a system doesn't have to worry about \"saving\" power for when humans need it, the system can operate when power is available, and got quiescent when the sun isn't shining or the wind isn't blowing.", "CO2: plants does it using a lot of solar energy, viable artificial methods exist too H2O: require a lot of electricity we are better off if it simply falls down CH4 (methane): simply burning it would reduce the greenhouse gas potential, but for that it needs to be concentrated. Separation in O2 environment is possible chemically but isn't possible economically. CFC(freon)/HFC: I haven't even heard of a system that would deal with this high potential gasses. CFC is banned since the Kyoto protocol because the damage to the ozone layer. Theirs efforts to phase out HFC from heatpumps, ACs, fridges. NOx: it's the group of nitrogen oxides which is created when air contacts hot things like a fire. This group is all over the place, some help plants grow when it comes down with rain some cause cancer. Collecting them after release is just as difficult as CO2, but converting them back to N2 and O2 require the same amount of energy if not more that have been wasted to create them in the first place. With perfect burning conditions this would not be created, oxygen likes carbon and hydrogen more than nitrogen. But perfect only exists in labs and the lack of air is more dangerous causes CO which is deadly in small quantities more is preferred. So even if we deal with all the other this group makes abounding energy from fire undesirable besides other disadvantages.", "It's possible, but very costly in terms of energy, and therefore also costly in terms of money. What most of the greenhouse gases have in common is a carbon atom. While some elements can form gases in their own, carbon cannot. So, for one, we can't just turn co2 into other gases. We have to do something with that carbon atom. And that's especially difficult because co2 is a low energy molecule -- it's very stable. Think of a staircase, and you have a bunch of golf balls. The higher up the staircase a golf ball is, the higher its energy state, and the less stable it is. A small bump can make a ball bounce down several stairs in one go. But you have to apply significant energy to these golf balls by hitting them upward, to hope for a chance they'll land and stay put on a higher step. Analogously, you can take something that is high energy and just stable enough to maintain its composition with no external forces (like gasoline), and by supplying a small amount of energy (like a spark), cause it to reassemble its components violently, releasing a bunch of energy. Otherwise, you must supply a lot of energy to a stable molecule, such that it disassembles, and then has a *chance* of reassembling its components into that somewhat stable, but higher energy state. That's the short story \\^. Due to this extreme cost, it actually reaches a political level. To make an impact, the energy required would be at least as much as all the electricity that is currently generated today, dedicated to this process of \"carbon sequestration (reclamation)\". So it would require the construction of an extra power plant, for every power plant currently in operation. And it would all have to be \"renewable\" energy, of course. Entropy is a bummer. There is no 100% efficient process. So, consider how much work a car can do with 1 gallon of gasoline. That's actually much less than the total energy in the 1 gallon of gasoline. Car engines are only about 25% - 35% efficient compared to the theoretical. So, a 100% efficient process would need 3x to 4x the energy that a car harnesses from 1 gallon of gasoline, to recreate 1 gallon from the byproducts of combustion. But, that's impossible, so in practice we may predict that it would require on the order of 10x the amount of energy that was harnessed in the first place. That already sounds expensive, and we still have to engineer that process. There has been research into this, though. [The most promising I've seen uses a special catalyst to convert co2 into ethanol.]( URL_0 ) Ethanol is a somewhat stable liquid at atmospheric conditions, which makes it somewhat suitable for sequestration; is already a useful fuel, fuels being what we're trying to replace; and is also a basic organic molecule that has potential to form other more complex organic molecules. That is, other processes can take ethanol, add the requisite energy, and convert it into those things we currently use oil to manufacture. Catalysts are used to tease the disassembled \"building blocks\" into being more likely to stay in the desired formulation. Per the golf ball analogy, it's like using a tunnel with a bump at the end, so you can purposefully hit a ball and it will stay on a specified stair -- as long as the correct energy is supplied. In this process, they achieve a 70% rate of getting it to stay as ethanol, instead of other random alcohols or other carbon molecules. Edit: To get closer to the crux of your original question, we might expect it to be possible to create better stable carbon molecules directly from solutions of co2 -- more stable and lower energy than ethanol -- but it doesn't seem to be widely published that this is a thing thus far. And if possible, cost, again, is probably a major hurdle. Creating lump of carbon for no other purpose than to be reburied underground will never return profit; it will always be somebody else's problem." ], "score": [ 1528, 63, 29, 21, 18, 15, 12, 6, 5, 4, 4, 4, 4, 3, 3, 3, 3 ], "text_urls": [ [], [], [], [], [], [], [], [], [], [], [], [], [], [], [ "https://en.wikipedia.org/wiki/Carbon_capture_and_storage" ], [], [ "https://www.anl.gov/article/turning-carbon-dioxide-into-liquid-fuel" ] ] }

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{ "a_id": [ "h3k36vq", "h3kqkkd", "h3k3jzj", "h3l3df9" ], "text": [ "Cold air that comes in contact with a flame will produce a sound because the air rapidly expands.", "The rapid heating and expansion of cool air creates sound. This is why lightning produces thunder, as the sudden (massive) change in heat causes a huge disturbance in surrounding air, which we hear for miles.", "Sound = vibrating air. Anything that moves air, makes a sound. Hot air moves up while cool air moves down, so a fire makes sound too.", "When a gas is hot, it’s molecules are vibrating/moving around super quickly. When a cooler gas is introduced, the hot gas wants to share its energy with the cold one, so the hot gas encourages the colder gas’ molecules to vibrate faster. The hot gas will vibrate slower because of this, but all the gas wants to be the same temperature/energy level. With the rapid change in vibration speed, some of that gas gets compressed together. Gas doesn’t like to be compressed, so the molecules move away from the source of the pressure. Several layers of compressed gas will do this very quickly, which creates the ‘sound waves’ you’re familiar with." ], "score": [ 88, 11, 8, 8 ], "text_urls": [ [], [], [], [] ] }

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{ "a_id": [ "h3k7etu" ], "text": [ "So, it is possible that compared to their birth date age their bones may be slightly less developed then a typical child of that age, since they were less developed coming out of the womb. But, it’s only really at most a few months of missed development, so by the time the child is 5, yes they might be “off” by a few months, but it isn’t super significant. You also need to consider that not all child ages the same way, some have growth spurt young and stop growing, some are short and have late growth spurts, some grow more constantly. So it is kind of hard to compare kids age to their bone maturation, since 1 twelve year old might still be growing, while the other is already pretty much the height they’re gonna stay at." ], "score": [ 13 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3kcg6z", "h3kclbh", "h3kdma8" ], "text": [ "Three reasons working together in conjunction: 1. Crabs are small. Burrowing crabs are particularly small. Since your strength depends on the square-cube law, it means crabs are relatively strong. 2. Crabs are built to live underwater. They're already adapted to having large amounts of pressure on their body, as long as that pressure is fairly even. 3. The sand the crab is buried in helps distribute the weight. Some of your weight spreads outwards (thus not affecting the crab), while some of your weight pushes back inwards on the crab's sides (helping support the crab's body from the reduced weight from above). With the pressure now being more even, the crab's bits don't really have anywhere to go, and so stay put, un-crushed.", "If I had to take an educated guess, it would be two things: crabs do have that nice protective shell and equal force ratio (or it's called something like that?) Basically when sand is packed together it provides resistance against the pressure your feet put onto it when you walk. That's why you kick up more dry sand and dont sink as quickly in wet sand", "Other answers here are good, here's another way of looking at it you can test yourself. Get something heavy like a 10 pound weight. (Gently) put it on your hand. Now, remove the weight, put a pillow on top of your hand, then put the weight on top of the pillow. Notice how much less pressure on your hand there is, and how what pressure there is is more evenly distributed on top of your hand?" ], "score": [ 9, 3, 3 ], "text_urls": [ [], [], [] ] }

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{ "a_id": [ "h3kluer", "h3kl6m4" ], "text": [ "The way the bonds work is not only the question of the numbers filling a valence shell. The electron orbitals have a geometry to them. You can perhaps think of it as two shapes \"sharing\" a face. The shapes of the orbitals of the carbon atom don't \"allow\" two of them to easily share 4 faces. This is why carbon atoms bond into patterns like flat hexagons (graphene) or tetrahedrons (diamonds).", "Imagine you’re a carbon atom approaching another carbon atom. A single bond is an overlap of two circular electron clouds that surround the nucleus. To make a double bond, you then have to bind a second electron cloud that floats “above” and “below” the nucleus. To make a triple bond, you then have to bind a third electron cloud that floats “left” and “right” of the nucleus. The fourth theoretical cloud then has to partially exist *behind* the atom, a location that your cloud (also behind you) can’t reach. ELI25: the third p orbital can’t overlap due to the first and second orbitals locking the atoms into position." ], "score": [ 4, 4 ], "text_urls": [ [], [] ] }

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{ "a_id": [ "h3kp46n", "h3kpf0o" ], "text": [ "the sheet vibrates in what is called \"eigenmodes\". it wobbles more or less like a two-dimensional spring system. Some locations are near rest, called \"nodes\", and this is where the sand accumulates. The eigenmodes (and thus node structure) depends on the shape of the sheet and the frequency. Higher frequencies usually mean more/denser nodes. The shapes are symmetric as the sheet is symmetric.", "The table will have areas of low or no amplitude where the sand settles because it’s been pushed by areas of higher amplitude. Vibrations produce the cool geometry. Not sure it can go the other way" ], "score": [ 4, 3 ], "text_urls": [ [], [] ] }

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{ "a_id": [ "h3kr7mb" ], "text": [ "Your skin has a bit of water on it. When you touch the surface it freezes quickly and your skin is stuck to it. The layer is so thin you can usually just pull your hand off of it to break the ice." ], "score": [ 4 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3lj4y9", "h3kqq8z", "h3kqxbc", "h3kzetb", "h3lkcso", "h3lnmf9", "h3lm70t", "h3ln05t", "h3lf0oc", "h3mbf35", "h3lrisx", "h3me6xf", "h3lm11q", "h3luixj" ], "text": [ "So the three lightest elements (hydrogen, helium, and lithium) are what we call \"primordial\". That is to say that [they formed along with the universe]( URL_5 ) and most of the atoms of those elements are from that time (though some, like some H4 nuclei which some radioactive atoms release when they decay, can also be formed from other processes). Elements up to Iron were mostly formed by what we call \"[stellar nucleosynthesis]( URL_0 )\", which are normal fusion reactions in stars. In order to get all the way up to iron by fusion, though, you need a big star. Our sun is too small to fuse anything heavier than helium together (creating carbon in the triple-alpha process, thanks u/Cecil_FF4)! Fortunately for us, the bigger the star the shorter the lifetime, so there's been lots of time for big stars to build lots of heavier elements and die, blasting some of them into space for them to become part of our solar system. Heavier elements still are created by more violent and energetic things that happen in space. When very large stars die, they undergo a massive explosion called a \"supernova\". A supernova is vastly more powerful than anything we can imagine, and a large star so dying may release as much energy in a second or two as our sun will release in *billions of years*, and when they do so [they create huge amounts of all sorts of atoms, much of which is then blasted into space]( URL_2 ). Other high-energy events can also create lots of certain elements. For example, two neutron stars (the remnants of dead large stars) merging creates a *lot* of gold and blasts it out into space, and [it appears that much (perhaps even most) of our gold was made in such a merger]( URL_4 ). There are some other ways certain atoms can be made. One of the most common is if they are part of the chain of atoms that is made when a radioactive atom decays. Others are made when [atoms in deep space (or even in our atmosphere) are struck by other fast-moving particles, which can change them into different atoms]( URL_3 ). Sometimes rare reactions occur inside the earth, which can make [traces of some rare, shorter-lived radioactive atoms]( URL_1 ). All these big explosions and fast-moving particles not only create every possible combination of protons and neutrons but also mix and swirl up the gasses and dusts that are floating around in space, so that by the time the earth formed, almost ten billion years after the universe did, at least some of pretty much every atom that could be present was. TL;DR: All kinds of crazy, high-energy stuff is going on in space. After billions of years of that, just about every type of atom that can be created is and then is all mixed up in the cloud that became the solar system!", "The current theory of how earth was created was billions of years ago some stars exploded and threw dust everywhere. The extreme energy in this explosion combined atoms into larger elements, and it would make every element including unstable ones. As the dust combined and settled into our solar system all those different elements landed on earth.", "All of the elements we find on Earth were created by the star that preceded our sun, either during its life time, or when it went nova. Those elements were then scattered pretty much uniformly throughout our solar system, which then coalesced to form our sun, the planets, and the other celestial objects of our solar system. Since there wasn't anything that would exclude any elements, the Earth would naturally contain some amount of all of them (at least those that were stable or have a significant half-life).", "So a lot of people are saying that elements on earth were made in the explosion of a star, and they're kind of correct. Data actually suggests that most elements here on earth were born in the collision neutron stars. There is a PBS spacetime episode explaining how they know, and it has to do with the specific isotopes that would be created. There are processes involving the heat and pressures that are created in the event, and how they would form those specific isotopes, vs a standard supernova or other event. Almost all elements are capable of being created in these events. The unstable ones decay, the stable ones also decay, but stick around longer. Scientists can estimate the abundance of the unstable elements that used to be in the system based off the material left behind that it has decayed in to. As for unknown particles, the standard model of particles physics has been -very- good at predicting elements, including unstable ones. We didn't always know as much as we do now, and using the standard model, particles were predicted that were later confirmed through experimentation to actually exist. It's this combination of theory and actual experiment that allows scientists to understand whether they're on the right track, or not, and contrary to what someone might think, most scientists get more excited about a result that does NOT fit the standard model than a result that DOES. To them it means there's possibly a piece missing that can be ferretted out. Problem is, these days missing pieces are so small, it's getting harder and harder to design experiments to figure them out, but it IS being done, one of the latest I'm aware of being the Muon G-2 experiment", "Everyone is approaching this question from a physical standpoint (star explosion), but it’s important to answer this question from an administrative standpoint. The periodic table is just an organizing system which conveniently organizes elements in a specific manner (first level of organization - number of protons, second level - atomic orbitals). This organization system was a way to organize physical data collected through early chemistry experimentation. We find everything on the table on earth because we organize it around what we see/know. Now keep in mind there are a lot of elements that “exist” but only in the lab because they are unstable. // Really I think of this as a chicken/egg question.", "Do we know those are all the elements there are? Genuine question I hope someone has an answer to.", "I'd argue it would be stranger if any would be completely absent or beyond our detection. Stars create all but the simplest of atoms in the universe, by nuclear fusion, when they explode and when their husks collide. Nature is messy. There end up to be regions with less iron, less hydrogen, or less gold than average, but none truly void. On a human scale it looks like we have loads of everything. On a planetary scale most elements are barely there in amounts worth mentioning. To just slightly exaggerate, anything beyond the Top 10 is practically only a minor impurity in Earth crust. We just relatively recently got very good at sorting through stuff to 'sieve' it all out. A lot of it is very hard to find. Many of the answers here appear to boil down to \"All the elements on the table are found on Earth, because the elements are put onto the list when we found them on Earth, haha!\" The original question is already phrased so it is clear OP understands that is not the case. But a lot of people seem to have that misunderstanding: The periodic table is not simply a list of everything we happened to find yet with random numbers assigned. It is made up of literally all existing elements ordered by the number of protons in their nucleus, which defines an element, and grouped by certain properties that repeat, well, periodically. There are no gaps left, we filled them one by one. Actually sometimes with the help of the table, because we could predict the properties of the missing elements by their periodic neighbors and thus knew what to look for. \"All\" we do now is append one when it's confirmed to have been systematically synthesized in a particle accelerator. Those do not exist naturally anywhere else in the universe. (Ask a physicist if they could technically be created for a nano-second in a super nova or something like that, what I mean is there are no planets made of the stuff.) The next one, 119, whenever some team manages to do it, will be an alkali metal. So, it would act similar to Lithium, Sodium or Cesium. (If it could be made in sufficient amounts to examine it and if it wouldn't practically immediately decay again.)", "Your question is as elegant as the answer. Suns function through fusion. Hydrogen is fused into helium then to lithium then beryllium. An old sun like the one in this solar system before our current sun had time to make every element on our periodic table one after another. That's why it's every single one because they grow by one electron, one neutron and one proton. it's like a ladder. every step is an atom and the sun before ours climbed all the way to the top... as far as we know lol.", "The answer is right there in your question. A swirling gas cloud is going to be pretty evenly mixed. Not perfectly evenly mixed, but well mixed. Since all the elements and isotopes were evenly distributed in the cloud, the mass of that cloud that formed the Earth would have had all the elements in it. In fact, it could have had more elements than it has today. The event that created all of Earth's uranium and gold would also have made technetium and plutonium. They've all decayed by now, but could have been hanging out in the cloud and swept up into a forming Earth. That imperfect mixing is also useful to us. We can tell that rocks here on Earth came from Mars because they have an ever so slight--but detectable--different ratio between isotopes that don't exist here but match what we've seen on Mars.", "Just for the record, when OP said \"we know the periodic table doesn't have any holes\", its literally because of how the periodic table is defined. I've seen people try to argue otherwise, but it's like the alphabet...we know there's no letters between \"A\" and \"B\" because that's the freakin' alphabet. except that it's even more objective than that...1 proton = Hydrogen, 2 proton = Helium, 3 proton = Lithium. there's no half protons", "This Awesome Periodic Table Shows The Origins of Every Atom in Your Body [ URL_1 ]( URL_1 ) [ URL_0 ]( URL_0 )", "Here's a slightly different take: Two of the common types of radioactive decay are *alpha* and *beta* decay. Alpha decay is when an atom loses two protons and two neutrons (also known as an \"alpha particle\"), and beta decay is when an atom loses an electron. So when an atom undergoes alpha decay, it becomes a different element two steps lighter on the periodic table. Beta decay will cause it to jump *down* one step. Uranium-238 is massive, but relatively stable as radioactive isotopes go. The [decay chain for uranium-238]( URL_0 ) has fourteen steps (with plenty of branches) on its journey to becoming lead-206. Each of the elements in between will have their own half-lives, with longer ones allowing the element to persist longer until it decays further. Despite all this, current science reckons that much of the universe is still overwhelmingly hydrogen-1, and our corner of it is still mainly lighter elements. Everything heavier than iron (starting with nickel-58) makes up less than 1 part per million by atom count, and less than 1 part per 10,000 by mass.", "Think of the universe as a big mixing bowl. In the beginning of the universe, there were only really light elements such as Hydrogen, helium, and lithium. But along came stars, which fuse lighter elements into heavier elements. Now, as these first generation of stars finally started to run dry they exploded and spread out some heavier elements into the mixing bowl that is space. And stars keep being born, but out of the ever heavier mixture instead of only the light elements (But mostly the light elements as there are still much more of those). Now our star, the sun, which is around 5 billion years old still fuse light elements into heavier elements but when it was born it was born out of a mixture of old star stuff as well. And the Earth was formed from the same old heavy star stuff, sans the light elements that fuel our star since those blew away in the solar winds as our sun started revving up. TLDR: We can find most elements here because stuff happened and got mixed around in the universe in the 9 billion years before our planet was formed.", "TL:DR; If you do random things enough times, rare things happen! Imagine flipping a coin ten times. Most often, you will get five heads, and five tails. Now repeat this exercise, many times. Sometimes you will get 7-3, or 2-8. Once in a while, you will even get a 9-1. But if you keep repeating that exercise, you will get every potential outcome, from 10 heads, through 10 tails. The amount of atomic interactions involved in creating the matter that makes up the earth is hard to picture. But there are patterns in that creation. Just as the ten coin flips comes up with some common outcomes (like a 4, 5, or 6 heads or tails), some of the simpler elements come up most frequently in the Earth - Oxygen, Silicon, Magnesium, and Iron. However, there are occasional '10/10' elements, too. Rare earth elements, for example. A few others that you know about are rare, but they 'floated to the top' of the Earth's surface, so they are found more often in the Earth's crust (where we live!) rather than in the mantle and core (which we don't know as much about, but we can estimate what's there!) So some 'very lucky' series of events lead to the rare earth elements, the 'big' elements like Uranium, and similar elements. How come every element on the periodic table Not quite. The element named *Technetium* (abbreviation Tc) is extremely rare. It is naturally unstable. So any Tc that is found is not 'created', but it was something other element that 'turned into Tc' as it decayed, and it will decay again someday into another element. But, out of the first 92 elements in the periodic table, 91 naturally occurring elements is pretty complete!" ], "score": [ 2076, 1619, 143, 106, 16, 8, 8, 7, 7, 6, 3, 3, 3, 3 ], "text_urls": [ [ "https://en.wikipedia.org/wiki/Stellar_nucleosynthesis", "https://en.wikipedia.org/wiki/Plutonium#Occurrence", "https://en.wikipedia.org/wiki/Supernova_nucleosynthesis", "https://en.wikipedia.org/wiki/Cosmogenic_nuclide", "https://arxiv.org/abs/1306.3960", "https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis" ], [], [], [], [], [], [], [], [], [], [ "https://www.sciencealert.com/images/2017-01/solar-system-periodic.jpg", "https://www.sciencealert.com/this-awesome-periodic-table-shows-the-origins-of-every-atom-in-your-body" ], [ "https://en.wikipedia.org/wiki/Decay_chain#/media/File:Decay_chain(4n+2,_Uranium_series).svg" ], [], [] ] }

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{ "a_id": [ "h3l0iqk", "h3l0pr3" ], "text": [ "Magnetic fields lines are like contour lines to show height on a map. They are a way to visualise the varying magnetic field strength or height. There aren't actual lines. But, if you put iron filings down then they will point in the direction of the field, in the same way as you can see which way is down a hill by pouring a bucket of ping-pong balls down it. The iron filings will tend to join up if they are close together, giving the appearance of lines. There aren't quantised lines there in the absence of the iron filings!", "The real field does not form lines. It is continuous. We often use lines in diagrams to represent the directionality of the field, but it is not actually composed of 'lines'. Or at least, if it is, there are infinitely many lines packed densely together. The idea that a finite number of lines exist just makes things easier to grasp. Think of them like lines on a topographic map. They are discrete representations of a continuous change. Iron filings align with the direction of the field, but they will not actually form discrete lines. Like a bunch of people in a crowd turning the same direction, it creates a visible directionality, but they haven't all suddenly lined up. Ferrofluid gets odd. This one I'm less certain about, but since there aren't discrete magnetic field lines, the spikes certainly don't form at each line. They do, of course, form in the direction of the field." ], "score": [ 8, 6 ], "text_urls": [ [], [] ] }

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{ "a_id": [ "h3kxpo7", "h3kzz8z", "h3ldncj", "h3kxeof" ], "text": [ "The three body problem are just three bodies (planets or stars for example) of similar weight (so you can't just ignore one) interaction with each other through gravity (orbiting each other) It can't be solved because they can follow deterministic chaos. That means all the equations describing it cause an infinite, nonrepeating pattern of movements. So you can foresee it a little bit into the future, but the further you go the more it depends on tiny details of the initial condition (generally dubbed butterfly effect) You can achieve the same unpredictable behavior with a [chaos pendulum]( URL_0 ) For the math cracks: this is described by the lyapunov exponent, wich gives a measure how fast tiny differences grow. For the solar system the prediction horizon is 230 million years", "In physics, we can use math equations to predict how something is going to move. If you drop something on Earth, you can expect it to accelerate downward at 9.81 m/s^2. After 1 second, you can expect that the thing you dropped will have fallen about 4.9 meters. After 2 seconds, it will have fallen 19.6 meters. If you swing a pendulum, there's a fairly simple equation to figure out the time it takes to swing back and forth. 2\\*pi\\*sqrt(length/g), where g is the gravitational constant and length is how long the pendulum is. There are also equations that can predict how long it will take a moon to orbit a planet, and therefore where the moon will be after a certain mount of time. There's another, more accurate equation for how a moon orbits a planet and how the planet is affected by the moon. This is the two-body equation, since there are two gravitational bodies involved. There is no such equation for, say, a planet with two moons or a star with a planet that has a moon. This is a \"3-body\" problem, because there are 3 gravitational bodies in the system. There is no mathematical equation that can precisely predict where each of the 3 bodies will be after a given amount of time.", "Just to add on: the three body problem exemplifies an issue that largely does not exist today. When one says \"it has no solution,\" what is meant is that it has no **closed form** solution. That is, you cannot write a series of equations that says \"the position of body 1 at time t = 3+4\\*sin(t) or the like. It can only be represented as a differential equation (or, if you like, an integral). With the advent of computers, however, the three bodies trajectories can be determined easily. You can plot the position of all three bodies as they evolve in time with some relatively simple computer code (there are, however, implications about the computer's rounding errors that have very interesting conclusions about how well one can predict these trajectories in the future). If one wanted to do this even in Poincaré's time (late 19th century), one would have had to **be** the computer, and do all the calculations by hand. This is not diminish the interesting fact that the 3-body problem's solution **cannot** be written down in closed form; that a relatively simple problem like this has no closed form solution. This was a conclusion that was of great interest to mathematicians and physicists following Newton's publication of the laws of gravity. And it has deep conclusions about the ability to predict the future trajectories of these bodies.", "The \"three body problem\" is the idea that no gravitational/electrically charged system where you have 3 or more objects can be solved analytically, that is, solved such that you can know the precise positions and velocities of all bodies at any time using an equation that describes the entire system. You can do that for a 2 body system, but having more stops any solutions from being analytical. You can solve it \"numerically\" where you take the starting point, move a bit forward, calculate positions and velocities, and repeat." ], "score": [ 39, 14, 12, 8 ], "text_urls": [ [ "https://youtu.be/QVgVyHVV0ew" ], [], [], [] ] }

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{ "a_id": [ "h3l54yz", "h3l4x5s", "h3l3i8f", "h3l4959" ], "text": [ "It's the percentage of couples who would get pregnant using that method of birth control Vs the amount of couples who would get pregnant with no birth control. So if 10,000 couples used no birth control and 100 got pregnant, than out of 10,000 on a 99% birth control only 1 would get pregnant.", "Oftentimes, this percentage is *per year*. So, if a contraceptive is 99% effective, that means that 1% of couples who use it will get pregnant per year, not 1 couple per 100 per times they have sex. Like you said, if 1 condom failed each time per individual act of sex, that would be *a lot* of accidental pregnancies.", "It's really hard to count \"during conditions where you would get pregnant\". Instead they count number of years of your \"normal\" sex life. So if 100 couples use the pill correctly for a year and one of them gets pregnant, that's 99%.", "I feel like it’s more about liability and the company covering their butts. If they said it 100% effective and you got pregnant, that would open them up to lawsuit. Saying it’s 99% and you get pregnant “sorry that you’re the 1%”" ], "score": [ 18, 13, 5, 3 ], "text_urls": [ [], [], [], [] ] }

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{ "a_id": [ "h3l70gz", "h3l664n", "h3l75aj" ], "text": [ "It was a gradual evolution. The last remaining evolutionary branch of fish on the path to become land animals is the lungfish. It is able to both breathe under water and breathe air through two separate organs. At first it was probably an adaption that allowed the fish to get some oxygen from the air when swimming in oxygen poor waters. This gives them access to more feeding ground then their competitors and might even help them escape predators. But the lungfish is taking this a step further and can actually live entirely on land for shorter moments. So it can essentially walk between ponds and even climb around waterfalls. That means there are a lot of lakes that are only accessible by lungfish giving them a huge advantage. There was a long development of different species between lungfish and purely land animals where the fins became better and better at climbing rocks, the lungs became better, it could survive for longer in the sun without drying out, the gills started disappearing, etc. Eventually you ended up with amphibians which mostly lived on land.", "We can't say for sure, but the most likely explanation is that tetrapods who evolved to live in shallow water eventually evolved to have both lungs and gills (allowing them short access to land), and then eventually dropped the gills as they moved onto land more permanently. For a more detailed description; URL_0", "That's not how evolution works. An animal never gives birth to an animal of a different species. Evolution works by small changes that gradually accumulate over a long period of time. It might be hard to imagine how the transition from underwater to on ground could happen gradually, but it did. Imagine an area by the coast, such that's covered by water during high tide, but forms separate pools at low tide. If two pools are close together a fish might be able to flop from one pool to to other, which could be a survival advantage. Fish that can flop to a pool that's slightly farther away would be more likely to survive and reproduce. Eventually, you might get fish that do that regularly. They'd still spend most of their lives in the water, but would be able to leave briefly when necessary. After millions of years, enough changes could accumulate that the animals could stay on land indefinitely, though they would still be born and reproduce in the water, like modern amphibians." ], "score": [ 9, 6, 4 ], "text_urls": [ [], [ "https://evolution.berkeley.edu/evolibrary/article/fishtree\\_09" ], [] ] }

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{ "a_id": [ "h3l84vh" ], "text": [ "An edition is after the manuscript is edited. Basically if changes are made to the text. Spelling corrections, grammer, rewrites etc. An impression is a reprinting of the same edition. So if you got a book from the 4th time they printed the 3rd edition it would be the 4th impression of the 3rd edition" ], "score": [ 10 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3lp0gw" ], "text": [ "As part of SETI (Search for Extraterrestrial Intelligence), some scientists had radio telescopes listening for signals around a certain frequency, which they speculated might be used by aliens trying to contact us. Let's look at [this image]( URL_0 ) of the Wow! signal data. Each column represents a different frequency near this special frequency. As we go down the rows, we go forward in time. The number or letter represents how loud the signal was. The number indicates how many standard deviations away from background noise the signal was at that moment. So, a blank or a 1 means the signal was basically just baseline background noise. A 2 or 3 means there was a bit of signal, probably just noise. But as the number gets higher, it becomes extremely rare to see such high numbers. If the number is higher than 9, its starts printing letters instead. A is 10, B is 11, and so on. So, the circled part goes 6, 14 (E), 26 (Q), 30 (U), 19 (J), 5. These are crazy high. This signal was super loud. And they only appear in one column, so this signal was only at one very specific frequency, not any nearby frequency. We never really figured out what could have created this super loud, very specific signal, so it's an interesting mystery." ], "score": [ 10 ], "text_urls": [ [ "https://upload.wikimedia.org/wikipedia/commons/d/d3/Wow_signal.jpg" ] ] }

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{ "a_id": [ "h3lyjf7" ], "text": [ "Dextrose is added to iodized salt primarily because it's a cheap and effective stabilizer for potassium iodide. Over time, the potassium iodide added to iodized salt tends to break apart into potassium and iodine, which reduces its effectiveness in the body. A stabilizer like Dextrose minimizes the effect. The actual amount of sugar as dextrose in iodized salt is low enough as to not have dietary significance." ], "score": [ 19 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3ly6wg" ], "text": [ "Shedding is a sign of life, animals shed hair, and new hairs take their place. Once the animal is dead and the pelt is treated, the hairs are fixed in place." ], "score": [ 24 ], "text_urls": [ [] ] }

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{ "a_id": [ "h3m3q4x" ], "text": [ "Melanoma is just one type of skin cancer, other types are basal cell carcinoma and squamous cell carcinoma Melanoma is uncontrolled growth (cancer) of cells in your skin called melanocytes Those are the cells that produce melanin, aka pigment, aka skin color The way UV radiation causes melanoma is that DNA damage from the radiation triggers mutations in the melanocyte cells, which results in uncontrolled cell growth (cancer). Since it's right on the surface of your skin is very removable if caught early. Once it spreads deeper into your skin or to other parts of the body, it becomes much more difficult to treat and can be deadly. Re fairer skinned people being more at risk: Melanocytes produce two types of melanin (pigment): eumelanin and pheomelanin Eumelanin is able to help protect the skin from sun damage, while pheomelanin does not Naturally darker skinned people have more eumelanin, so they are less at risk Naturally fairer skinned people have more pheomelanin, so they are more at risk FMI: URL_0" ], "score": [ 5 ], "text_urls": [ [ "https://www.skincancer.org/skin-cancer-information/melanoma/#what" ] ] }

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{ "a_id": [ "h3mfmrt" ], "text": [ "Indexes in a way are yes just lists of companies on the market combined together, really well known ones include the Dow or S & P. This is why you hear about companies being added/removed from these indexes. These typically have a wide variety of companies on them, which is why they are used to represent the market generally." ], "score": [ 3 ], "text_urls": [ [] ] }

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