Subset (10)

eli5 · 25k rows

Split (1)

train · 25k rows

query stringlengths 20 300	positive listlengths 1 1	negative listlengths 1 1
Why are tears shed when crying?	[ "\"Is there and evolutionary advantage\" Well it's a lot easier to indicate that you are sad/need attention (as a child) if you're crying. When mothers see their young cry they get triggered by hormones and gives the child attention, and a caring mother means a higher chance of survival. It's basically a signal to ...	[ "The rods and cones in your eye (the vision receptor cells) only contain a finite amount of rhodopsin (the chemical that absoarbs light). After it absoarbs enough light, the chemical needs to be recycled, which takes some minutes. Until that time, those cells can no longer detect light or \"see\"... thus according ...
What gives acid a burning property like Sulfuric Acid? Why doesnt Vinegar or Lemon juice "burn"?	[ "They do. The acid in lemon juice and vinegar can trigger the same chemical reactions as sulfuric acid, but they're much weaker and the reactions aren't nearly as intense. Lemon juice can be used to make a battery, can cause mild burns on sensitive parts of your skin, and can even \"cook\" food in ways very similar...	[ "The voltage is too low to push the electricity through your skin. But if instead you try licking the terminals of a 9 volt battery you will get your tongue shocked since it's wet and offers less resistance. These videos are great at illustrating how it works: _URL_1_ and _URL_0_" ]
What is the most likely way the universe will end?	[ "We don't know for sure, but the prevailing theory is [heat death](_URL_0_). Basically, every single particle of matter will eventually decay into thermal energy. Since thermal energy is only useful when there are differences in temperature, eventually the temperature will even out across the universe and it will n...	[ "Gamma ray burst. It travels at the speed of light and would usually give almost no warning." ]
Are there any metals with a curie temperature high enough to keep magnetic properties into a plasma state.	[ "Above the Curie temperature, a ferromagnetic material becomes paramagnetic. This means that instead of having well-aligned magnetic spin, neighboring particles have randomly aligned spin. A plasma is very similar to a gas which happens to contain a large concentration of electrically charged or ionized particles. ...	[ "Basically thanks to section k of [this law](_URL_0_) the Secretary of the Treasury can mint a coin in whatever denomination he would like as long as its made of platinum. This is relevant because what Tim Geithner (our current Secretary of the Treasury) could do is mint a 1 trillion dollar platinum coin (note this...
What's the purpose of fracking ?	[ "Fracking is > the process of injecting liquid at high pressure into subterranean rocks, boreholes, etc., so as to force open existing fissures and extract oil or gas. It's done to extract oil or gas from the ground. We use these substances for energy." ]	[ "Think of a game - or any computer program - like a recipe. Do this, do that, do this other thing. At some point in a copy-protected game, it'll do some check to see if it's allowed to install or run; maybe check a serial number or make sure the right disk is in the drive or (and this is old school) ask for the 4t...
Siblings share 50% of my genes, grandparents 25%, so how are chimps 98% similar?	[ "There's a difference between DNA, which is what the 98% number is measuring, and genes, which are long sequences of DNA bases. Genetic variation within the human species allows for small differences within the DNA of each gene. Some of these differences have effects and some don't, so the diversity isn't always vi...	[ "Genetics and Immune system explanation time. Basically, the way your immune system works is that certain proteins are present on your defense cells that will attach to certain other proteins, called antigens, on other cells. It's how they attach to bacteria. Due to complicated genetics, your body and organ cells h...
Which planet in our solar system has the closest to a human-breathable atmosphere, excluding Earth?	[ "Jupiter's moon [Europa](_URL_0_) has a very thin atmosphere which consists mostly of Oxygen. It would be a good place to tank up some oxygen before going for interstellar journey. If you really want a planet that would be Mars. It's atmosphere is almost completely carbon dioxide, but that is still far better than ...	[ "There has been some theories of silicon based life. It is similar to carbon, but the bonds aren't quite as strong. Obviously there's no proof of it, but from what I've read it's the most probable element behind carbon." ]
what is that extra flap thing of material in women's underwear?	[ "From an old comment in [r/AskWomen](_URL_0_) > It is not a pouch, it is called a 'gusset'. > > It serves two main purposes: > > 1) It is an extra barrier to catch... hrm... bodily fluids/discharge etc. > > 2) It also allows for breathability. It sounds strange, but lack of air flow around the vagina and urethr...	[ "Those lines are the defrost functionality for the rear window. Basically if you turn on that functionality they heat up, which defrosts your back window." ]
How do banks basically work? Like how do they return interests and how do they earn a profit?	[ "In the most basic sense, they take the money deposited to them and loan it out to other account holders. Say your savings account earns 1% interest on all the money held there. The bank would then borrow that money, combine it with other account holders’ money, and loan it out to someone for a house mortgage or ca...	[ "The rules of baseball are can get extremely complicated because there are so many nuances so I'm going to give you a very watered down version; a version a five year old would understand. The object of the game is for each team to play through 9 \"innings\". Whichever team has the most runs (points) at the end of...
Zeroth derivative is position. First is velocity. Second is acceleration. Is there anything meaningful past that if we keep deriving?	[ "They have the following names: jerk, snap, crackle, pop. They occasionally crop up in some applications like robotics and predicting human motion. [This paper](_URL_0_) is an example (search for jerk and crackle)." ]	[ "The proton move through the C transmembrane peptides on Asp61, this causes structural conformation changes within the F0 domain causing rotation, this is linked to the F1 domain by the stator which means they both turn at the same time, with the gamma domain working as an axle altering the conformation of the beta...
What makes an object elastic, and what can be done to change an object's elasticity?	[ "Elasticity in most condensed matter arises from the equilibrium spacing between bonded atoms, which is weakly dependent on temperature and strain, for example. Elasticity in some elastomers (e.g., rubber) and in gases arises from entropic considerations and is strongly temperature dependent. Is this the kind of in...	[ "Think of a currency like any other commodity, with supply and demand. Let's say a British person wants to buy a TV from America. The TV costs $500, but the British man only has pounds. He exchanges his pounds for dollars, and buys the TV. Now, someone in America has a bunch of pounds that they can't use, unless t...
What would happen if a cystic fibrosis patient were to contract cholera?	[ "It has been [suggested](_URL_0_) that the cystic fibrosis mutatation is so abundant because it confers resistance to cholera when one mutated copy is present. This cited paper shows that mice with a double CF mutation are not strongly affected by cholera toxin, at least with respect to intestinal fluid loss." ]	[ "why would you eat your mentor? but the reaction will cause you to vomit uncontrollably sort of like putting baking soda in vinegar." ]
Why don’t all atom bombs have the same yield if it’s just splitting an atom?	[ "Two things. 1. More bomb. If you add more atoms to be split, you produce more energy in total. So the destructive effect of a bigger bomb naturally increases. 2. More complex bomb. Atomic bombs are actually not very efficient. A lot of material is left unsplit and a lot of energy goes to waste, especially with bi...	[ "Basically they all start from the oil we pump out of the ground.All of these things are inside that oil. We then heat the oil in a large tube that has many different levels. As the oil heats up all the different parts become a gas at different temperatures and they settle in the level where the temperature is cool...
How does the "Captcha/write what you see in the photo" thing help confirms that you aren't a robot?	[ "Robots are really bad at some things people consider simple tasks. Like recognizing pictures of cats, or transcribing jumbled words." ]	[ "The most common business model is just to get as many eyes looking at your site as possible, for whatever reason, and then sell ad-space. Advertisers will pay for people just looking at their adverts, but they'll pay more if people click on those adverts, and they'll pay even more if you can use your knowledge abo...
Why are there almost no meritocracy based countries?	[ "Because people are stupid and corrupt and can't implement any system effectively because they're too greedy! It's like how communism works great in theory, but horribly in practice because humans are bad at being unbiased and stuff" ]	[ "\"Just about everyone here\" Where is \"here\" for you? It sounds like your question's premise is based on a small sample set based on personal observation. Before your question is addressed, you should be making sure the premise is valid..." ]
With so many end of the world prophecies being consistently proven wrong, why do there continue to be true believers of the next end of the world prophecy?	[ "Because the true believers aren't true believers that someone will predict the end of the world, as much as they are true believers of the charismatic individual that they follow who happens to prophecy the end of the world. Usually they are already sucked into the group, and it's not usually the same people that ...	[ "We are all subject to a circadian rhythm which dictates our sleep timings. A couple of factors include exposure to light and our body's release of supplement called melatonin. Many babies, for example, are naturally nocturnal. That is why parents have to sleep train them. After that, they will typically get tired...
Why do plants not grow on hiking trails (the path)?	[ "The constant foot traffic compacts the soil and smashes any sprouting plants that might try to pop up, thus it is very difficult for plants to grow on the path. Furthermore, many trails are actively maintained, so in the event that a trail does start to become grown over, there are teams that will go through and c...	[ "Anyone feel free to add but according to a PHD in physics: \"They do, and you've just never noticed. But if you have a big enough mirror and can point it toward a radio tower, you can test it out yourself. Point this big mirror at the FM radio tower, and get out a portable FM radio. Now start at the mirror and sta...
The difference between NP, NP-hard and NP-complete	[ "They all involve solving problems in a reasonable amount of time(if you have a CS background, \"reasonable amount of time\" means polynomial time complexity). NP is a problem that can be checked in a reasonable amount of time. So if I state a problem and I see a solution, I can pretty quickly check to see if the s...	[ "Dr. Terrence Tao, a renowned mathematician, is working on the Navier-Stokes existence and smoothness problem. In 2014, he had a big result for a certain form of the equation. I was still in college at the time and my PDE professor said that most of the mathematics community expects him to be the one to win the pri...
Why North America prefers HTST over UHT milk?	[ "HTST milk lasts longer after opening. In my experience, a gallon lasts a week and a half after purchase if kept refrigerated. UHT milk seems to go sour very quickly after opening (3-4 days). I don't know if this is an effect of the country where I live, or the actual price, but HTST milk was a lot cheaper in my ho...	[ "The dental plaque on Neadnerthal teeth shows evidence of plant grains that have been cooked: > Here we report direct evidence for Neanderthal consumption of a variety of plant foods, in the form of phytoliths and starch grains recovered from dental calculus of Neanderthal skeletons from Shanidar Cave, Iraq, and S...
Why do some lesbian women adopt a manly (For lack of a better term: "Butch") look.	[ "Regarding the male lisp thing: There was a thread some time ago with the same question. A nurse or EMT talked about a couple of stereotypical \"effiminate\" gay men who would forget their lisp briefly when regaining consciousness from an accident or anesthesia. This leads one to believe that the lisp as you call i...	[ "> how it really amounts to a bunch of bologna I don't have an answer, but I do need to point out that bologna = lunch meat. Baloney = nonsense." ]
Why do new shoes "burn" your feet?	[ "Usually new shoes are tighter in different places, compared to the shoes you normally wear. Walking in new shoes therefore results in a lot of friction between your skin and your shoes/socks. Friction = heat, that's why blisters form." ]	[ "Oilskins. Soak linen or canvas with linseed oil, let it dry. You can also treat cloth with wax, or tar, and ,later, raw rubber. All these would have problems- oilskins would tend to stick to themselves, had to be carefully hung up and stored, as did rubber ones. Tar and wax don't bear much heat. Animal skins will ...
If, from earth, we can see Venus as a white-pinkish dot, would we see the Earth as a blue dot if we were on Venus? Assuming that ideally there were no clouds and the sky was clear.	[ "Yes. As seen from space near Venus, the Earth would be very obviously blue, slightly dimmer than Venus as seen from Earth, and would have a dimmer silvery dot (our Moon) right next to it. I don't believe any photos have been taken of the Earth from spacecraft at Venus, but here's a black-and-white telescopic photo...	[ "There's an amazing portion of Lucian's \"True History\" wherein the narrator's fleet gets swept up into the stratosphere: > About noon, when the island was no longer in sight, a whirlwind suddenly arose, spun the boat about, raised her into the air about three hundred furlongs and did not let her down into the se...
I've heard you can understand the American Revolution and Civil War as a Continuation of the English Civil War. Is that true?	[ "A slight problem with this theory is that the Puritans supported parliament against the Stuart kings. King George III was of the Hanoverian line, which was brought in by parliament because George I was the only relative of Queen Anne who wasn't a Catholic. Also, though George III gets scapegoated a lot for cau...	[ "Different theorists who divide the world into \"Civilizations\" categorize Latin America as either a part of Western Civilization are simply as Latin America. The controversial Samuel Huntington explicitly excludes Latin America from the Western World in his divisions of world civilizations. Other theorists like A...
In monarchies with a newly-crowned child ruler, who was responsible for determining Regency appointments? Why was the ruler's mother such a common choice?	[ "In the court of the Chinese emperors, there were three power bases that would have access to the person of the Emperor: the officials, the eunuchs, and the Empress (roughly in order of proximity). During the Han dynasty, it was common for there to be a symbiosis between the Imperial Court and the Imperial in-laws....	[ "greetings all. Just a moderator reminder to potential respondents of what subreddit we're in here: it's /r/AskHistorians, so do review and comply with [the subreddit rules](_URL_11_). In a nutshell: > Answers in this subreddit are expected to be of a level that historians would provide: **comprehensive and inform...
Why is so hard for the brain to read sentences with random words in it ?	[ "When we read something, our brain takes shortcuts and uses \"sight words\" to process the sentence without reading every little thing. When those clues and cues are not followed, the the brain trips over itself and struggles to comprehend the \"new\" sentence pattern. Sort of like if you are walking up steps and ...	[ "Context. The thought was formed in one environment and an association created. When you pass through a doorway you're passing into a new context and the association is lost." ]
How do we are able to sometimes sense somebody's presence or gaze before we actually get to see or hear such person?	[ "You can't actually sense someone's gaze on you. There's no mechanism that would make that possible. You just remember the times when you felt someone's gaze, turned around and saw someone because those times were interesting and, well memorable. You forget the times when there was no one there. This is an example ...	[ "Simply put for the same reason drinking water when you're not thirsty isn't as refreshing as when you're REALLY thirsty. Anticipating the bodies' needs doesn't trigger the same reward responses in the brain as fulfilling a need that is already present. Your muscles don't NEED to stretch right now, so you can't ant...
Does skin grow back (or does it just stretch)?	[ "The stratum basale is the most basal layer of the epidermis, which makes up skin. It contains keratinocytes, which can be considered stem cells of the skin. These undergo differential maturation as they proceed to form the stratum corneum which is the visible skin you can see. So yes, skin can grow back." ]	[ "In your example given, asthma is the body's immune reaction and not necessarily a function of the lungs so no, the person would still have asthma. -Correction in reply below Now, if someone had nerve damage in their hand (not resulting from a spinal issue) and successfully recieved a hand transplant, in theory thi...
Why does every element have the same number of protons as it does electrons?	[ "If there are more protons than electrons, it is a positively charged ions and electrons are attracted to it until it gets neutralized. If there are more electrons, it is a negatively charged ion and the extra electrons are repelled by the nucleus until it is neutralized. If there are the same number, neither happe...	[ "Nothing. That's pretty much the definition of \"elementary.\" They are the smallest building blocks that we currently know of." ]
What would the orbit look like in a dual sun solar system?	[ "Astrophysics dude here. The answer is: complicated. Three-body-interactions such as those involved in planetary orbits in a binary or trinary star system can pan out any number of ways, depending on the dynamics of the system. How big a planet? How close to the stars? how close are the stars to each other, and how...	[ "[Here's a java demo of a double mass-spring system](_URL_3_). The motion of these types of systems can often be described as a sum of [normal modes](_URL_4_). In the geometry you described, a common normal mode is for the masses to sort of [pass the oscillation back and forth](_URL_0_). There are plenty of other s...
Are kleptomania and socioeconomic status linked?	[ "kleptomania is a really terrible mental disease. The individuals have an obsessive and compulsive urge to take things. The people who are taking things do not want the things they take, they just want the action of taking them. It isn't just \"this person steals a lot\" but rather \"this person cannot control thei...	[ "I get that they are \"bottom feeders\" but to be fair if someone doesn't repay their debts (of at least the principle amount) they ultimately stole that money. Thanks in advance for the downvotes ;)" ]
If it's 90F outside, why is my car 120F inside?	[ "Heat is transferred in different ways, and some of these go into your car, but not out. This is the \"greenhouse effect\". Heat from the sun arrives on Earth in the form of radiation. Radiation can pass through air, and through your car windscreen. But it gets absorbed by the things in your car, like the seats and...	[ "The temperature sensors in your skin can only detect relative changes in temperature. Not absolute temperature. You can show this by doing a simple experiment with three cups of water. one cup of ice water, one cup of room temperature water, and one cup of hot water. Place a finger of your right hand in the ice w...
How can we know of places that have almost no human rights i.e north korea but do nothing about it.	[ "Because, contrary to what we tell five year olds, fixing problems is not always as simple as just Doing Something. If anyone knew how to deal with North Korea without causing even more harm, they'd do it." ]	[ "Basically because the conditions in sweatshops are better than the alternative for the workers (not working or subsistance farming) and buyers (the companies that buy from the sweatshops) only care if it affects their sales. You can fire everyone if there are a hundred times as many employees who are doing someth...
how does a gps (ie: googlemaps on phone) determine traffic even on the smallest local streets?	[ "\"Google Traffic works by analyzing the GPS-determined locations transmitted to them by a large number of cellphone users. By calculating the speed of users along a stretch of road, Google is able to generate a live traffic map. Google processes the incoming raw data about cellphone device locations, and then excl...	[ "Simpler explanation: I write you a letter that says \"This letter was sent from < my address > on < date > and < time > . Please send me a letter back as soon as you get this, with the exact time and date you received this. You follow the instruction and send the second letter back to me. When I get your letter, I...
Why do companies insist on telling the public there's "scheduled maintenance" when a web site is clearly broken?	[ "In this particular case, we have a way of stopping traffic that lets us try and fix the underlying systems while we shunt incoming traffic...unfortunately it put up an inaccurate message but it was pretty far down the list of priorities to fix that! For the best info, stick to _URL_0_." ]	[ "Imagine driving a long distance on the road. Your destination is 160 miles away, so you drive along the highway at about 80mph and figure that you need about 2hours total. Then, in the middle of that 160mi, the road gets very bad (you had no chance of knowing that) so you can drive only 50mph. You don't know if th...
Was Hitler really obsessed with the occult?	[ "This is a pretty common question here; here's some links from the FAQ: _URL_2_ _URL_4_ and a few others that have been posted over the years: _URL_3_ _URL_1_ _URL_0_ Most posts agree that it is largely a post-war pop phenomenon with fairly little evidence to support it." ]	[ "Is this what Doctor Strangelove was based on?" ]
Can you answer seven (7) questions about quantum computing? It wouldn't make sense if I ask each in separated topics.	[ "I would like add a couple of observations to /u/functor7's answer. First of all, the most important thing about qbits is not a state of one qbit, but what can be the state of several qbits. While one qbit can be in superposition of 0 and 1, two qbit together can represent superposition of 00, 01, 10, 11, and thr...	[ "> there's really no such thing as \"pages\" on Reddit. Instead, you're saying \"give me the links (from my current 50 subreddits at this time) #1 to #[page size] as ranked by voting right now at this exact moment\"... When you go to the next page, you're saying \"give me links #[page size] to #[page size2] *at thi...
I am too much of a neckbeard to understand /r/niceguys. Do girls really not like nice guys?	[ "It is kind of sarcastic. \"Nice guy\" in this sense is a man who thinks he is \"nice\", but is subtlety resentful towards women for not choosing him, and blames them for his lack of romantic success. The typical Nice Guy has trouble approaching women romantically, so he will befriend them, do them favors, then fe...	[ "Self posts, like this one, earn no karma. The automatic 1 upvote you give yourself on everything you submit earns no karma. Looking at your history, you have no submitted links (not self posts) that have more than 1 upvote without the same or greater number of downvotes. Basically, if you want karma, you have to l...
Is there any scientific basis for so called "Hitting Weather" in baseball? When it's warm out most commentators say home runs are likelier to hit.	[ "Sure, when it's hot out, the air density is lower, so the drag on a baseball is lower and you can hit further. Occasionally airlines deal with the same issue -- they have to cut weight because the temperature at the runway is overly high, and this makes the air less dense which makes the airplane produce less lift...	[ "How far apart are the two sessions? Food doesn't necessarily heat up uniformly in the microwave. Some parts get more energy input vs. others, due to microwaves having standing waves inside and because microwaves only heat up water (edit: I'm wrong about this part. Microwaves heat up polar molecules, not just w...
If principle photography is done AND a teaser trailer is out, why wont the new Star Wars be in theaters until next December?	[ "Post Production. This is when all of the CGI, sound mixing, editing, scoring and much much more is done. Additionally, they're will probably be reshoots. Therefore, the one year gap gives them plenty of cushion time." ]	[ "You can't just \"swing by\" any planet you want to use as a slingshot, the planet must be in a very specific place at a specific time. Launches are typically organised to fall in places where this is possible, but it isn't always and the trajectory New Horizons is using is probably the best one they can get for a ...
If the Crab Nebula is 6,523 light years away, how can scientist know it was a supernova that created it only 1,000 years ago? Would we need another 5,523 years for the light to reach us to even know it happened?	[ "It blew up (6,523 + 1,000) years ago. 1,000 years ago when Chinese astronomers observed it, they observed it as it blew up 6,523 from before then. When we look at the Crab Nebula now we are looking at images 1,000 years after the super nova that have taken 6,523 light years to get here." ]	[ "We don't know for sure... but assuming Earth is average, we can look at how long it took for multi-cellular life to arise here and assume that's how long it takes, then apply that to how long we believe Mars might have been conventionally habitable. I haven't looked up the numbers recently, but I'm fairly confiden...
Why does staying up late and waking up at a normal time have a different feeling of tiredness than going to sleep at a normal time and waking up early?	[ "An hour before midnight is worth two after 😉 seriously, one of the reasons we sleep is to clear [chemicals](_URL_0_) from the brain. The longer you go without sleep, the higher the levels of these waste products will be, so presumably the longer they will take to clear. Therefore the longer you're awake the longe...	[ "Entropy man. It takes more energy to keep something \"clean\" or \"arranged\" than it does to let it go to chaos and become a mess. Put a bunch of strings in a box and shake it. Things will get tangled up quickly, and take more time/energy from you to untie/unknot the item(s). User /u/crnaruka answered this best i...
What is the biological mechanism behind immunosuppressants and how do their functions differ across drugs?	[ "There are so, so many mechanisms behind immunosuppressants. They could be inhibitors of inflammatory cytokines (ie interleukin6, tumor necrosis factor alpha, interleukin 1b); synthetic immune suppressive cytokines (ie tumor growth factor beta); inhibitors of costimulatory molecules, stress hormones, phosphorylatio...	[ "CPU cores communicate cache line locking and staleness information between each other using a bus protocol such as [MESI](_URL_1_) or [AMBA/AXI](_URL_2_). These protocols are then used by the CPU to implement atomic instructions such as `lock xadd` on x86 and `ldrex/strex` on ARM. Edit: Here's an article that give...
If water conducts electricity, why does humidity prevent static shock?	[ "It allows the electrical charge to dissipate through the air. Rather than \"building up\" on an object to be \"released\" when it gets touched." ]	[ "He's covering the sugar in a hydrophobic coating. Scotchgard is a common one. [Here](_URL_0_) is a video of sand with a hydrophobic coating. Note that when he picks it back up out of the water, it's dry. This happens because water won't stick to or penetrate a hydrophobic surface. So, the sand/sugar stays \"dry\" ...
How prevalent was drug trade and use in the middle ages in Europe? Which were the most used drugs? How was it socially perceived?	[ "[Here's a link to a previous /r/AskHistorians question on this subject.](_URL_0_)" ]	[ "Sorry, we don't allow [throughout history questions](_URL_0_). These tend to produce threads which are collections of trivia, not the in-depth discussions about a particular topic we're looking for. If you have a specific question about a historical event or period or person, please feel free to re-compose your qu...
In the United States, politicians are required to declare party affiliation, but why is it also required of the voters?	[ "It isn't required of the voters. In some states, you need to register as a member of a party to vote in that party's primaries, but otherwise you can mark yourself as independant (or nothing; probably varies by state) and regardless of your party you can vote for whoever you want in general elections." ]	[ "Copying a post I made on this a few months ago: > Segregation was a major headache for the State Department from post-WW2 until the passage of the Civil Rights Act. They spent a lot of time soothing ruffled feathers of African diplomats - it was quite common for them to be harassed when travelling between Washing...
Why are movies not available in 4K, even though they are filmed in 4K and played in 4K in the theater?	[ "It's just a issue of them being delivered to the consumer in a cheap way. That's why VHS was a thing... When movies were only shot on film they were shot on 35mm or 70mm... Obviously stuff not that average Joe could use at home. Those film reels were actually the equivalent of 4k-5k.. But its all fancy and expensi...	[ "Bitrate. I don't know what Vimeo streams at, but 1080p 30fps on YouTube streams at a max of around 3.8Mbps (depending on the original file size). 1080p 30fps on Netflix is 5.8 Mbps (if using Safari or IE for your web browser), and apps like HBO Go/Now streams 1080p 30fps at around 8Mbps. To give you a frame ...
What starts the pumping of the human heart and how does it keep going?	[ "You don't sound dumb. It's a good question. The heart has its own electrical system that keeps it pumping independent of brain function. Sometimes it misfires, though, and that can lead to things like heart attacks. Basically, as long as there's blood flowing through the heart to keep it alive it doesn't even need...	[ "Much of the power generation done in the world is done through thermal turbines. A fuel is burned which generates heat, that heat is used to make pressurized steam is forced through turbines. That mechanical motion is used to spin magnets in the generator which through induction induce electrical current in the li...
You have been transported to a planet somewhere else in the Milky Way. Is it possible to deduce where you are in relation to Earth? If so, how would you do it, and what equipment would you need?	[ "Yep! By using pulsars as beacons. Each pulsar has a very particular spin period, no two are exactly the same and we know them to very precise values. We know accurate distances to relatively few of them, but enough that by identifying the positions of these pulsars on the sky, we could accurately determine our 3D ...	[ "It's nighttime. Here, have a telescope. See that building way over there? You can pick out details in the rooms that are lit, maybe even see people, what they're doing, etc. Now using the telescope, in your own dark room, find your car keys." ]
What would a displacement-time graph look like for an increasing acceleration (jerk)?	[ "It would look like a cubic polynomial. [Apparently google graphs functions now](_URL_0_)" ]	[ "These links may help until someone else qualified to answer comes along. _URL_2_ _URL_0_ _URL_1_" ]
What exactly does a "karat" measure?	[ "Carat (with a C) is a measure of weight for precious gems. Karat (with a K) is a measure of purity for precious metals. So, a 24 karat gold nugget gives no indication of its weight, only that it's pure gold that has no other metals added." ]	[ "Think about things bouncing around. Imagine a box with a fan in it. Put 20 balls in ithe box. Now imagine a basket to one side just the right size for the balls. Turn on the fan. The balls jump around randomly. At some point a ball will fall into the basket. This will happen at a given rate which will depends on h...
In a binary star-system, should one star go supernova, what would be the effect on the other star (provided the original doesn't become a black hole)?	[ "First, an aside on black holes: Whether the progenitor becomes a black hole or not is irrelevant - the gravitational fields of a star and a black hole of the same mass are the same outside the surface of the star. In other words, at large distances, it's just as easy to orbit a black hole as it is to orbit a star...	[ "Yes! The child would be what is called a [chimera](_URL_0_)! He/she would have some areas of the body made of the twin's cells and some of its own cells. There was actually an instance where a chimera woman almost lost her kids because they were found to be not a genetic match, but they actually were hers and *her...
Historians involved in Public History, would you recommend this profession for someone going to school for history?	[ "You might be interested in [this Theory Teusady](_URL_0_) and [This AMA](_URL_1_)." ]	[ "Get a feel for what you are reading. Ask yourself do all their arguments follow? Are they sometimes making leaps of logic? Are they priviliging/relying one group of sources, if they are do they explain why? What perspective is the book written from, how might this affect the focus of the book? Are they making bad/...
If I access the internet on my own phone through the companies wi-fi, can they see what I've been browsing and does this create any legal worries?	[ "Yes they can see everything that goes through. If you're using SSL they'll only have the websites visited, not logins or anything like that. I personally don't trust any public hotspot or access point. If I need to do anything remotely sensitive (that requires a login) I route through my home VPN or use 4G/LTE. L...	[ "because much of your tax situation involved information that the govt and your employer do not have. Things like charitable contributions and other tax deductions, tax credits for things like using green energy, income from investments and savings." ]
How do physicists define energy?	[ "Basically, energy is something that is conserved in systems that look the same if you move them forward or backward in time. This is a consequence of something called Noether's theorem, that associates conserved quantities with symmetries. Another example is momentum, which is conserved when something is the same ...	[ "Just as a side note, E = mc^2 is not as simple as you think. That's just a degenerate form of the equation where momentum is set to zero. The full equation is: E^(2) = (mc^(2))^(2) + (pc)^(2)" ]
why do flies rub their little hamds like they are plotting world domination?	[ "Flies are actually very clean animals that groom themselves vigorously. They start with rubbing the dirt off their hands, then usually pull along their antenna, windshield-wiper their eyes, etc." ]	[ "The general consensus is [attention and approval seeking](_URL_4_) or [medical issues](_URL_1_). In [domesticated animals](_URL_2_), the approval seeking is generally from the owner. Because we see this in wild animals as well, it can't just be a human-approval mechanism. The attention seeking can be extended to t...
What is the difference between a photon being reflected and a photon being absorbed and re-emitted?	[ "The macroscopic phenomenon called reflection is, in its quantum mechanical basis, absorption and emission events - and each time a photon is absorbed and emitted, momentum is conserved. I'd advise you to read [QED: The Strange Theory of Light and Matter](_URL_0_). It describes, in laymen's terms, probability ampli...	[ "Looking at an object in a mirror is the same as looking at the object at a distance of (distance from you to mirror) + (distance from object to mirror). To see something, light travels off of an object, through the pupil and to the retina. The pupil focuses this light so that lands correctly on the retina. Blurry ...
Why does every software support team send me a new terms of service? And what do they mean for me as a user?	[ "EU's new data protection law (called GDPR) came into effect the 25th of may. It says that basically all (user) data collection should be disclosed and opt-in. This means that every service that ever collected data has to update its EULA in order to do business in the EU." ]	[ "Imagine driving a long distance on the road. Your destination is 160 miles away, so you drive along the highway at about 80mph and figure that you need about 2hours total. Then, in the middle of that 160mi, the road gets very bad (you had no chance of knowing that) so you can drive only 50mph. You don't know if th...
[Question] Do things lose mass as they are smelled?	[ "The act of smelling does not cause mass loss, but if you can smell something then it is because mass has been lost from the thing. We smell things when certain molecules hit receptors in our nose. The only way to get them to our nose is to turn part of the object into a gas and have it escape the object into the a...	[ "Very little. The density of air at oven temperatures is going to be about 1.1 kg/cubic meter (1000 liters), so you've got about 110 grams of air in there, max. Now, air (by weight) has about twice the heat capacity of steel (although I'm not sure of that holds at oven temperatures), but even so, you have a lot mor...
What happened to the stock market last Friday?	[ "One problem in China is arising from an expected \"credit crunch\". It's expected that Banks in China will begin giving out less loans which can hurt he growth of many industries. From a Fed and Bond standpoint, Fed chairman Ben Bernanke has recently alluded to the tapering off of Quantitative Easing or QE. QE is...	[ "I'm confused? When you sue someone you don't take away all their assets in most cases. Just the amount needed to repair the damages. Also, Fannie and Freddie aren't the only lenders, and they aren't a traditional lender in the first place." ]
Why is having an imaginary friend such a common thing among children?	[ "I have to disagree with the premise that this is common. I've never met anyone who actually had an imaginary friend, but that's just anecdotal. I only know this is a 'thing' because of American TV, so I would presume that the reason it's perceived to be common is because it's something of a popular trope on TV." ]	[ "I'm the artist who painted the image of the \"Infant Stalin\" and his flying \"fairy godfather\" Ivan the Terrible. You can see the explanation at the link posted by RottenLittleKid _URL_1_ The image is actually part of a much larger triptych. You can see where this Infant Stalin and his \"godfather\" Ivan the Ter...
The phisiological difference between white meat and dark meat	[ "Dark meat is the muscle animals have, which they use frequently (like legs) So it contains a lot of myoglobin, which is constantly carrying oxygen to supply the muscle with energy. This also contributes to muscle growth. White meat (like chicken breast) is the muscle that's only required for short, brief bursts of...	[ "Well I caught this one way to late so this will be buried but here ya go. I was chef of a very large expensive Manhattan restaurant for several years. I am speaking specifically of tuna. The fish is graded by the wholesaler who buys the fish at auction or by contract at wholesale markets. There is no legal definit...
How did people wake up on time?	[ "[Water clocks](_URL_1_) were widespread for millennia before the introduction of pendulum-based clocks. For alarms, at least in Europe, people generally relied on [church bells](_URL_0_), which rang three times a day, at 6:00 AM, noon, and 6:00 PM. Of course, precision in timing was less in demand before industria...	[ "Back then people still needed jobs, now they dont and can practice harder for longer. And science helps by showing then methods on improving motions. You cam find cool videos on youtube" ]
Why was Greek city states able to resist Achaemenid Empire during the Persian War despite significant population difference?	[ "I answered this question in detail [here](_URL_0_). When we're talking about populations, the real question is how much of a state's population can be mobilised for war. The Persians were fighting an overseas campaign at a great distance from their heartland, which is logistically difficult, time-consuming and cos...	[ "Is this a homework question? It says in our [rules](_URL_0_): Our users aren't here to do your homework for you, but they might be willing to help. Remember: AskHistorians helps those who help themselves. Don't just give us your essay/assignment topic and ask us for ideas. Do some research of your own, then come t...
Is it possible to get sick from your own cold?	[ "You can catch the same cold, however if the strain hasn't evolved yet, the odds are that your immune system will already have the immunity built up from it the first time. So, if you were to come in contact with said cold again, your body would just fight it off much faster than the first time, when your body need...	[ "Imagine you are made of genetic soup. Some people have ingredients that just don't go well together and make the soup taste bad. But that's ok, because when you have a kid, we just take some of my soup and some of my wife's soup and pour it in together. So even though my soup has some bad ingredients, her ingredie...
What is the difference between an assault rifle and a machine gun?	[ "I think everybody else explained it well, but I like pictures, so I'm going to give you some pictures. Submachine gun. A small weapon that fires pistol caliber rounds, fully automatic, short range. [MP5](_URL_2_) [new, unnamed SIG](_URL_11_)[, Uzi](_URL_15_) Assault Rifle. Primary military weapon. Capable of auto...	[ "Coke Zero: Same taste, artificial sweetener. Diet Coke: Different taste, artificial sweetener. Coke Life: Same taste, mix of artificial and natural sweetener (so 60% less cal instead of ~0cal)." ]
Was the NYPD as corrupt in the 1960's and 70's as portrayed in popular media?	[ "Not a really comprehensive answer, but you should check out \"Savage City\" by T.J. English(_URL_0_) It's more anecdotal than sweeping in its coverage of police corruption at the time, but it tells some pretty terrifying stories about people being railroaded by corrupt polices. You do get the impression that this...	[ "Hi there! This is a reminder to potential respondents to this question that we have the [no current event rule](_URL_0_) in effect that in order to discourage off-topic discussions of current events confines questions, answers and all other comments to events that happened 20 years ago or more, inclusively (e.g. 1...
Was the Byzantine-Sassanid war in the early 7th century the main reason for the fall of the Persian Empire to the Muslim forces or were the Sassanids without a chance to begin with?	[ "Unfortunately I don't think that I can answer this myself, but I can point you towards a book that might help: Decline and Fall of the Sasanian Empire: The Sasanian-Parthian Confederacy and the Arab Conquest of Iran by Parvaneh Pourshariati. I've always been taught by my professors and Byzantinist peers that th...	[ "The Soviet Union established the borders between these now states in 1924 and 1928 (Tajikistan went from an ASSR to SSR in this year). Uzbeks, Tajiks, and Kyrgyz all lived in this area with weird borders known as the Fergana Valley. It has very robust soil and is known for cotton growth. The Soviets based the divi...
Do we have any information in regards to an approximate ratio between peasant and noble populations during the Middle Ages?	[ "Not exactly the Middle Ages, but in pre-revolutionary France it was 98% the third estate (25 million people) vs. 2% the remaining two estates (500 000 people). I imagine it was about the same in the Middle Ages." ]	[ "This one kinda goes past the Republic into the Principate period. At what point did Romans (mainly the literate and educated) realize they were no longer a republic, but instead a monarchy? How did they accept this given there was such a strong hatred for monarchy within Republican Rome?" ]
The trajectory of a bullet.	[ "For a 5-year-old: A bullet only has enough power to go a certain distance. If you shoot the bullet really high, it won't go very far forward, but if you shoot a bullet really far forward, it wont' go very high. There are a few big things that will affect the bullet speed though: wind and gravity. Wind will slow ...	[ "* Open your favourite FPS game. * Run across the map, keeping an object in the skybox at a constant angle in your view. You will go in a straight line. * Now run, keeping a nearby object at a constant angle. You will circlestrafe right into it. When insect navigation evolved, the only lights around were in the sk...
Why doesn't the very high upper class have higher taxes?	[ "They do have higher tax rates for higher incomes. The highest tax bracket is for those making over $405,101 per year and they are taxed at 39.6%, compared to those making under $9,075 per year that are taxed at 10%." ]	[ "Some do. The Duke of Marlborough still lives at Blenheim Palace, which is about as splendid as you get. But many in the British peerage just couldn't afford the expense of maintaining such expensive homes during the economic changes in the 20th Century, with a large number of them signed over to the care of the Na...
If the baby boomers are retiring from the job market. Why aren't there more jobs available?	[ "There are several reasons. 1) They are not actually retiring. They are being forced to keep working due to many economic reasons. 2) Automation is taking away many jobs." ]	[ "This is akin to asking why we don't have a cure for mosquitos. After all, couldn't someone just analyze the smell and appearance of mosquitos, and then develop a micro robot that specifically targets them? The pathways you describe are active research pathways, so far as I know. But research is hard, and actually ...
Who was in charge of mercenary groups used in wars (Ie Hessians/Swiss Guard/etc)?	[ "It varies by what group you refer to, of course. There have been pure mercenary troops used in history, literal private armies who fought for the highest bidder (if you're familiar with Game of Thrones, think of Daario's Second Sons.) These groups were prominent in the Thirty Years War, and were quite commonplace ...	[ "I cannot comment on the Annals, but in the Song of Roland, it's clear from the text that the author has very little real knowledge of those the author calls Muslims. He makes all sorts of descriptive mistakes that a person with even passing familiarity would not make (For example, Muslims are extremely monotheisti...
why do some forms of intellectual property have like 50 year durations before becoming public domain, while other copyrights seem to be forever?	[ "Copyright laws vary from country to country. Even within one country, the US for example, the laws are different for various durations due to the existing laws at the time the work was created." ]	[ "When you wake up in the morning, you get something called sleep inertia. It's the groggyness you feel up to two hours (usually half an hour) after you have woken up. It's a \"false\" kind of sleepy, which makes you want to stay in bed. This combined with how comfortable your warm, soft bed is, makes it so darn ha...
Can you listen to the radio using garden weeds and a high powered radio antenna? And how?	[ "An analog signal is basically sound vibrations converted into electromagnetic frequencies. The frequencies are picked up by antennas and converted back into vibrations by speakers. But a high powered frequency can cause objects to resonate and produce the same sound vibrations, for example the WLW once broadcast w...	[ "Are you asking about fiction shows or TV as in documentaries? In the case of the documentaries some places it is completely legal to grow. Others, well it’s not hard to hide really if you have the right setup. The hardest part is covering up smell. Some induction fans or blower fans with charcoal filters connected...
What happens to gravity when mass is converted into energy?	[ "Lets say you have some object with mass. It's mass causes gravitational attraction. If you could instantly turn all of the mass to energy, and somehow keep it all together in the same space the object occupied, this energy would have the same gravitational attraction as the object it came from. Both mass and ene...	[ "Well if you account for drag you would accelerate until you hit terminal velocity and fall at a constant speed until the centre of the earth. If you negate wind drag however, you would keep accelerating right up to the centre of the earth then start to decelerate at the same rate. In a perfect universe you would c...
What's France's northern coast like, in relation to an apparent historical lack of major ports in this region?	[ "Right now, there a lot of harbors in northern France _URL_1_ _URL_0_ Including the second biggest port in France, le Havre which is an historical port, founded in 1517 by king Francis 1, the French king of France. The port of Calais was also pretty important So I'd argue there were ports in northern France." ]	[ "In addition to what has already been written : - the EU started with 6 members, and was supposed to be limited to very specific stuffs (open market). They made rules accordingly : some decisions must be taken unanimously, and others by majority. - Now we have more than 25 countries. And the UE rules a lot more tha...
What is MSG and how does it affect my body?	[ "MSG is monosodium glutamate. Sodium is just the ion carrier for glutamate. It is common in many food items such as mushrooms, tomatoes, broccoli, walnuts, and peas. It has no negative effects on your body unless you're an (extremely rare) allergy sufferer (edit, for clarity: no known negative effects. All scientif...	[ "Could somebody explain how, if true, small amounts of alcohol is good for you?" ]
Why do smoke detectors run on batteries instead of mains power?	[ "Because fire may cut off power before the smoke reaches the alarm. Especially since quite a few fires start as a result of electrical issues. Making it completely self contained also means it's easier to install. And that's only home smoke detectors. Smoke detectors in large commercial and industrial buildings ge...	[ "Most US rail outside of large cities isn't electrified. Electrifying the huge stretches of rail in the rural US simply isn't economical. Electrified rail is more expensive to install and more expensive to maintain than traditional tracks. It makes sense in dense urban areas for stop-and-go commuter trains, but for...
What does an Atom actually look like?	[ "Quantum analogies are always difficult because nothing we're typically familiar with visually displays quantum phenomenon. The physical structure of the atom is fundamentally a \"probability cloud,\" which is the region around the nucleus where you have certain probabilities of finding electrons. It doesn't look ...	[ "Like this! Oh, sorry. Forgot you weren't a real 5-year-old." ]
Why are we more susceptible to telling the truth, or showing feelings we usually wouldn't when we're drunk?	[ "[relevant]( _URL_0_) I'm not a scientist, so I can't give an exact answer but that article is something I've always remembered. Apparently drinking doesn't make you more likely to do any specific thing, it just makes you care less about doing it. Giving credence to the saying \"being drunk doesn't change who you...	[ "Cause love is the only thing that matters in the end. Or in a less poetic way, the only thing evolution gives a shit about is how many surviving offspring you get, and how many offspring they get and so on. So we have evolved to form bonds that would help with the survival of our offspring. As far as evolution i...
If infrared light is detected by our skin as heat, can too much visible light cause the senasation of heat too?	[ "It certainly can. The easiest example of this is lasers, which are concentrated beams of visible light that can be powerful enough to melt certain metals." ]	[ "You sort of answered it with your last sentence there... A flame is a light source. Usually relatively bright, if you're looking right into it. The reason you don't see \"through\" it is similar to looking at bright stars versus dim stars in the sky. You technically CAN see through the flame, but the light coming ...
How can someone be a director and star in the same film?	[ "They are behind the camera - they have an idea of how they want the shot to look like and can provide director guidance to the other actors, work with the cinematographer (the guy who actually aims the camera, frames shots etc.) and the rest of the crew.... once the shot is set up exactly how they want, they can s...	[ "You get the full year's worth of radiation. From an outside point of view, we see that time is dilated and the astronaut is moving very slowly inside their spaceship. But we see the spaceship take a full year to reach its destination, and gets hit by all this radiation along the way. From the astronaut's point of ...
Why is linear algebra important in Computer Science	[ "It's almost too hard to enumerate all of the uses. Linear algebra has many, many uses in relation to signal processing, and discrete states (which CS is heavily into). For example, one notable use was Google's pagerank algorithm, which used properties of vector-matrix transformations to assign rankings to page pop...	[ "Imagine you are a travelling salesman, and you spend most of your time driving from place to place across the country. Today you need to get from Denver to Dallas. You could use High Level Navigation. You know how to get from Denver to Wichita, Wichita to Oklahoma City, and Oklahoma City to Dallas. String those to...
Why not send a drone to Mars that can recharge with solar panels?	[ "NASA is considering the possibility of a helicopter drone for a future Mars mission. You can read about this [from NASA](_URL_2_), as well as some articles on others sites, such as [this](http://www._URL_3_/28360-nasa-mars-helicopter-drone.html) (from _URL_3_) and [this](https://www._URL_0_/extreme/229937-nasa-tes...	[ "It's way, way, WAY, too expensive. The power plant alone would probably be more expensive than the entire lifetime cost of an average bulk carrier. Not to mention the insane mess of regulation that is involved with running a nuclear reactor. Basically, big ships run on bunker fuel, and bunker fuel is ludicrously...
Why do movie subtitle translations change the content unnecessarily?	[ "If the movie has a Russian dub, it could be a transcript of the dub (not a translation of the English). The reverse happens a lot in anime. Where the English subtitles are translated from the Japanese, not a transcript of the English dubbing. It's also possible that the person hired to translate the movie isn't pe...	[ "Are you watching blu ray? Is it a good transfer? (Example: despite being made in the early 80's Blade Runner Ultimate Director's cut blu-ray is one of the best you can buy) How good is your blu ray player? Is it a ps3? All of these factors contribute to what you determine as a home viewing experience being inferio...
if our body did not waste food during the digestion process,what is the least amount of food (by mass) we could live on	[ "This will be an incomplete answer, but it should at least get us into the ballpark. Assuming you could survive on glucose alone (which for a few days is perfectly reasonable) and needed to consume 2000 Calories a day, that would equal 500g of glucose (a little more than a pound). In terms of volume it would be jus...	[ "You don't start out knowing. You learn around the age of 2 and as your throat grows you learn to gradually take in as much as you can swallow. Some people don't learn and eat very slowly. 2 year olds put more than they can swallow into their mouths all the time. They tend to spit it out when they realize it's too ...
why do electronic's (phones, computers) speed slow after about a year?	[ "They don't, although you can have an experience like they do. If you just use the system without any changes and updates, it will work exactly as it always had. But looking at just phones for example: every year there are new phones out and old phones get binned. Samsung releases new galaxy models all the time, so...	[ "Your question reminded me of this frikkin awesome documentary of about planned obsolescence. [Video snippet](_URL_0_), and the whole documentary, I can't find... but Im sure someone else may be able to. ELI5 version: Because companies want you to keep them in business." ]
diverting an asteroid using paint.	[ "The natural asteroid material is very absorptive (close to a black body) meaning that the large majority of incident light is absorbed. This light has a certain amount of momentum associated with it which acts to gradually alter the path of the asteroid itself. By painting it, or part of it, white, we cause the in...	[ "Depends on the speed of the particles, but it is potentially lethal. [The ISS](_URL_0_) was hit by what is believed to be a sub-millimeter particle. It made a very visible dent in a window..." ]
Noise cancelling headphones	[ "Sound is made up of pressure waves - high pressure, then low pressure. One property of sound waves is that they can be mathematically added together, and this is what happens when you hear two sounds together. And if you add a high pressure bit of a wave to a low pressure bit, they cancel each other out. Noise can...	[ "They dont work. The hole is just so that plugs with a ground pin fit in, but the ground pin loses its function." ]
Why does it seem like when you are moving in the dark you are going much faster than you actually are?	[ "That could merely be a subjective experience, but this experience can be helped by the fact that your perception of far-off landmarks is vastly reduced. You measure movement by the movement of landmarks in relation to you, and at night you cannot see far-off landmarks. Because of this, you only see things that are...	[ "Because the animal inside you activates and you engage in \"Predator\" mode, doing everything in order to secure food and guarantee the survival of your species." ]
Is there always someone aboard the ISS?	[ "Yes, there is always someone on the ISS. I believe the crew is always between 3 and 6; the soyuz capsule only holds 3, so there are 6 while the current crewed soyuz is docked and 3 while people are being moved. This may be useful: _URL_0_" ]	[ "The SEIR model is one way of projecting how many individuals in a population are Susceptible Exposed Infected and Recovered when considering an epidemic that allows an infected individual to immediately transfer the parasite to another individual. Some parasites have latency periods where an indiv...
How do animals know which other animals to have sex with, if they don't know what they look like?	[ "Animals cannot identify themselves in their own reflections (for the most part). This does not mean that they can’t differentiate species, animals are dumber than humans but not that dumb." ]	[ "These sort of questions are really hard to answer under the auspices of \"science\". Someone can probably tell you a story based on a sort of \"evolutionary reasoning\" (and these stories are where a lot of evolutionary studies begin), but unless they can cite a serious research program that has investigated this...
Physiologically, what is a thought?	[ "Neurobiologist here. We don't have a good or complete answer. This is one of the most mysterious questions not only in neurobiology but in all of science because we can't confidently answer it without knowing what consciousness is, and we don't. So the short and unsatisfying answer that we have for now is that a ...	[ "Recent studies show a link to [dopamine](_URL_1_) which is a brain chemical." ]
What is white noise?	[ "White noise is simply sound signal with energy equally distributed across all bands/spectrum (basically, a pure random signal). I guess it is called \"white\" because it is comparable to \"white light\" containing colors from every wavelengths. Now about the rest of your question: What kind of input signal are you...	[ "Never heard of this before, googled, and now see it is a thing. Newsprint is very rough, meaning it is not smooth, but has tons of imperfections. Imperfections means debris can get trapped in it. Much like a shamwow or magic eraser, it is all about having a bunch of imperfections that can grab debris. News print ...
Could one of the first ever Homo Sapiens learn the same amount and same quality of information as a modern Homo sapien?	[ "Species don't discretely jump from one to another. They slowly evolve. There is no such thing as the \"first\" Homo Sapien because that would imply that his or her parents were of a different species. It's kind of like a probability density function. The probability of any fixed number is invariably zero." ]	[ "greetings all. Just a moderator reminder to potential respondents of what subreddit we're in here: it's /r/AskHistorians, so do review and comply with [the subreddit rules](_URL_11_). In a nutshell: > Answers in this subreddit are expected to be of a level that historians would provide: **comprehensive and inform...
What is a Faraday Cage and how does it work?	[ "It's simply a way of protecting something against electromagnetic radiation or electricity itself. It's a cage you sit inside, and if electromagnetic radiation or electricity hits it, it gets conducted around the cage, and out the other side, not allowing any of it to get inside. [This](_URL_0_) is a picture of ...	[ "[Richard Feynman](_URL_1_) ELI5's it pretty well in about 2 mins. Alan Alda had a contest and this [8 min video](_URL_0_) won." ]
Why does it appear Front Page Posts have higher vote numbers than in the past?	[ "[Capping has changed]( _URL_0_) . It seems posts were artificially limited beyond a certain karma and that number has increased. They eventually plan to do away with it altogether, but need to do it a little at a time so as to not mess up the sorting algorithm that encourages new content to reach the top." ]	[ "Better cables (copper) and fibers, better best practices, fixing bugs in firmware of switches, routers, network cards, faster cpus in network devices. Protocols are the same but im sure they are being constantly updated. Also routing protocols are better, routers works better, the infrastructure is much better tha...
What's the science behind a headache?	[ "The brain itself is not able to feel because there are no touch receptors or sensory neurons (at least, not the same ones as those that allow you to feel things) in the brain. What we perceive as a headache comes from when veins around the brain dilate, which puts pressure on the structures around the brain that h...	[ "I've deleted this thread because all the answers were speculation and assertion which goes against the spirit of /r/AskScience. Feel free to ask again at a later time where you might hopefully get a better response." ]
If you could get past the event horizon and survive, would it be really bright?	[ "X rays do not escape from within the event horizon either. The ones we see were never inside, but emitted from near the surface. To answer your question though, no, it would be pitch black. All the photons inside would be traveling towards the singularity, none would be traveling towards your eyes." ]	[ "From a Relativistic point of view, mass distorts space-time. In the case of a black hole the distortion is such that all the straight-line paths lead into the black hole. Light can't escape from a black hole because there aren't paths out of the black hole that the light can take." ]
How would a college with free tuition work?	[ "A college with free tuition would work because they would get the money needed to pay the staff and such from an other source. Usually that source is taxes. So either, taxes will go up to provide free education, or taxes will stay the same, but the budget will get restructured. One thing that has been suggested, f...	[ "traditionally .com was commercial. .org was non profit or some other organization. .net was network related site. .edu was educational. .gov was government website. some of these are reserved like .edu .gov but the others are fair game today. and they are coming up with increasing numbers of top level domain name...

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