Subset (10)

eli5 · 25k rows

Split (1)

train · 25k rows

query stringlengths 20 300	positive listlengths 1 1	negative listlengths 1 1
How did daguerreotypes work? What was the process?	[ "For that type of early photography you take a dark baseplate coated in silver and expose it to fumes from typically iodine or chlorine. This changes the pure silver to a compound that is sensitive to light. The places where the light hits are turned back into silver by that. So after exposure you get the image in ...	[ "In addition to /u/CoderInPhoenix's explanation another big factor is weight. Although I'm pretty sure taking only the camera portions of an iphone would be significantly lighter, ounces count. So that coupled with making it durable enough to withstand tons of sandblasting and using old technology makes it actuall...
If someone becomes incredibly obese, does their body create more nerve cells to cover their increased skin surface area?	[ "I am no expert in the field by any measure, however I distinctly remember hearing something about neurons stretching as an individual gains weight. Based on some information I have located the answer is yes. While I imagine that there is some neuro-genesis that takes place to create a few new neurons - they are l...	[ "Imagine you build a spherical shell around the sun, just bigger than the sun itself, and that the shell is absorbing all the incident radiation. Each square-meter of this shell would be receiving a very large amount of power from the sun. Then imagine you double the radius of that shell. Now, because its surface a...
What exactly is Torque?	[ "Torque is a rotational force enacted on an object. Basically the same force that lets you tighten screws, use door handles, and even pedal a bicycle." ]	[ "I thought it was explained pretty well by this old tek syndicate video _URL_1_ Definitely worth a watch!" ]
How can peat burn underground? upto two meters apparently; where does the oxygen come from in these conditions?	[ "From the air. Most parts of the underground are not 100% isolated from the surface, there will be ways for air to flow and diffuse there. The fact that the oxygen supply is limited is why underground peat fires tend to smolder for a long time." ]	[ "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 ...
What's the reason I don't remember every moment in my life? Is it because my brain is not recording every moment or my brain cannot retrieve what it has recorded?	[ "There is [a guy who can remember almost every moment since he was struck with a baseball in the head at age ten](_URL_2_), so the brain seems to record every moment and can theoretically retrieve it. Unfortunately this is only one interesting trivia I happen to know and I can't provide any further explanation of...	[ "They are kept in the device's RAM as you use the app, so that when you scroll back up, they are instantly available. Some apps may run out of RAM or otherwise optimize to save it, so the data will be erased from the RAM and lost, thus when you scroll back up, then it must re-load the data from the internet." ]
What are Lagrange points and how do they work?	[ "It's 1am here so this might be a little oversimplified and weird; lagrange points are points in space where gravity of different celestial objects cancel out. You might know that larger masses cause a larger gravitational pull. Also, gravitational pull is quadratically inverse to distance, meaning the further away...	[ "This video from Sagan will help. I couldn't explain it in a better way. _URL_0_" ]
If the radius of the observable universe is 62 billion light-years, then why is everyone saying the universe is 13.8 billion years?	[ "The universe continues to expand. Distant objects we see today were much closer to us when the light we are currently seeing was emitted. Those objects are now more distant due to expansion. Just as a note, if your interpretation were correct, the radius would be 13.8 billion years, not 6.9, since light 13.8 billi...	[ "The formula for the relativistic Doppler shift for EM radiation is, from wikipedia: f = F sqrt( (1-B)/(1+B) ) where F is the frequency in the frame of the source and f is the frequency in the frame of an observer moving relative to the source with velocity B = v/c. For B < 0 the observer is moving towards the sour...
How does the Hubble Telescope aim at one spot in the sky for days at a time if it is moving around the Earth?	[ "The thing it is pointing at is so far away compared to the diameter of Earth that it doesn't matter. The diameter of Earth is about 1/20 of a light-second, so if it pointed at a star 5 light-years away, the angular difference would be less than a milliarcsecond. The actual angular resolution of Hubble is [1/10 of ...	[ "In the case of 2001 it was actually really clever: They suspended the actors on wires just like a lot of movies used to do, but they built the set sideways and put the camera on the ground pointing upwards. This accomplished two things: First, the actor's body hid the wires so you didn't have to try to remove the...
If someone who wasn't trans got a sex change, would they also experience gender dysphoria?	[ "Yes. There was a book by a man whose penis was removed in a botched circumcision. Raised a girl and suicidally depressed with dysphoria. \"As Nature Made Him\" was the title." ]	[ "I'm sorry to have removed this question, but this falls under a poll-type question and is prohibited according to our rules. The problem with questions like these is that they invite speculative answers and the risk is that the thread is going to end up more like an /r/AskReddit thread than a thread we want here."...
What happens to your car if you speed a speed bump?	[ "If you hit it fast enough could blow out tires or damage your suspension." ]	[ "Usually steep fines and punishments when caught. And it is when caught, not if caught." ]
How can the observable universe be larger than the age of the universe?	[ "The most distant thing we can see is the Cosmic Microwave Background. The light from it traveled 13.7 billion light years to get to us. However, the matter that emitted that light is now 45 billion light years from us. This is because the metric expansion of space can result in the distance between two objects inc...	[ "Because the rate is the same. You can observe it for any period of time and extrapolate that rate of decay across whatever unit of time, whether it's days, months, or billions of years. Even if you observe it for a normal human period of time, there's still a tiny tiny change, and if you measure accurately, the ra...
the cause of the geometric patterns formed in sand with a tone generator	[ "[Standing waves](_URL_0_) If you shake a string at right frequency \"knot\" points will form that stay stationary. This is due to the wave created by the shaking and the wave reflected from the other end interfering with each other. Video: Standing waves on a string _URL_2_ Objects that are more complex than a st...	[ "Warning: anecdotal evidence ahead. I'd consider myself mathematically minded (studied Math and CS in college, currently working as a software engineer), and this is definitely true for me. I'm pretty terrible at remembering (and sometimes even understanding) song lyrics, but I'll often be in a bar or other noisy e...
Why do I have to take the lids off plastic bottles before putting them in the recycling? They lids are made of plastic too, right?	[ "The lids are to be recycled as well. They don't want bottles capped because it makes them more difficult to compact. Also, stronger plastic bottles can present a significant explosion hazard under compression." ]	[ "The \"sensor\" part of a metal detector is made of coils of wire, usually in a plastic of epoxy shell. Metal detectors don't detect metal directly. They detect changes is magnetic permeability. They send out a magnetic signal and measure how the surroundings effect it. Sure, many parts like the arm are metal, but ...
What is the best book for someone to read about A) the Sunni Shiite rivalry and B) the Kurdish struggle?	[ "For a book on the Kurdish struggle I suggest [Blood and Belief](_URL_0_) it talks about the history and development of the PKK, which is possibly the most popular Kurdish nationalist group right now and have a sister organization that runs Rojava. It also briefly dives into the issues between the PKK and the KRG i...	[ "I don't have the time to answer this in depth, but 1913: The Year Before the Great War by Charles Emerson seems to be exactly what you're looking for. Be careful not to adopt a teleological view of history - even though it's obvious to us that WWI 'will happen', people at the time weren't quite so convinced. T...
How does the 'Westboro Baptist Church' keep convincing their followers? What do they say every Sunday?	[ "They don't really get new followers. It's a family, not really a church." ]	[ "Wildlife photographer here. They do it with long lenses, and weeks of squatting in cold, damp nature blinds, waiting for the right scene to happen in front of them. I cruise around Yellowstone for days at a time with a 600mm lens looking for critters. Or if you happen to be Walt Disney, you cheat. For the 1958 wil...
How come there are diverse languages across the world and spoken among various people? I just don't understand the origin of any language.	[ "Because isolated groups of people develop their own way of communicating, and back when we first started to communicate we might as well have been isolated people. For example, let's say we take you and nine other people, and from the moment you were born you lived in total isolation from everyone else. you never ...	[ "A long history of dedicated, purpose-driven selective breeding programs. Most of the different breeds of dogs have been intentionally crafted by human breeders over hundreds or thousands of years. While the same is true (to a lesser extent) for cats, cat breeders focus on coloring and fur more than size and body ...
What has happened with the California drought?	[ "The amount of rain in California this year was unprecedented, and yeah, basically the drought is over. But we can't count on having such a large amount of rain every year, so conservation is still wise. This was the most rain in a year California has ever had in recorded history (except for 1982-1983). There are a...	[ "No one knows, though there is never a shortage of people who think they do. Thomas Malthus is arguably the most well known of that group; the scenario which you are describing was named after him: [Malthusian Catastrophe.](_URL_5_)" ]
How do transparent materials/substances exist?	[ "Think of a wire mesh, like an insert on a window. Because it’s so thin light get’s through no problem. It’s the same with most materials, if it’s thin enough some light will get through. Let’s add some thickness by stacking up layers of the wire mesh. After a few layers it’s hard to see through and after a few mor...	[ "It can and does. Check out the double-slit experiment. _URL_0_" ]
If the middle of summer is June 21st, and it's August 21st, the sun is at the same angle as April 21st. How come it's much warmer in August than April?	[ "The Earth is big, and it takes a long time to warm up. Temperature lags behind energy input." ]	[ "Your metabolism's job is to regulate the temperature of your body. \"Metabolizing\" food is basically like setting it on fire in your body and using the heat for energy. In the extreme heat, your body temperature is already high. So your body doesn't burn the energy it has as aggressively (your metabolism slows d...
How long before The Moon drifts far enough away from Earth to break orbit?	[ "The short answer: The Earth won't be around long enough to see the moon \"leave\" it! (at least according to theories about the prospective life expectancy of our galaxy.) If your interested in why it is moving away I recommend reading this short little article on BBC News:_URL_0_. In summation, it suggests that ...	[ "Potassium-40 which I guess you're talking about has a beta decay which means it has a continuous spectrum of possible energies for the beta particle. This means it also has a continuous spectrum for the recoil energy from the emission of the beta particle. It is this recoil energy that breaks (or doesn't break) th...
Do people in comas still have normal reproductive functions?	[ "I’m not sure of the logistics, but there was a news article recently which outlined how a woman in a vegetative state had given birth to a baby, which sparked a hospital investigation. You can probably find it by scrolling down r/rage" ]	[ "Hello everyone, Unfortunately, we have already had to remove a number of poor quality responses in this thread, including many asking about the deleted comments, which merely compound the issue. If you're here to answer the question, please make every effort to answer the question, not talk about the show, make...
in television/film credits, what is the difference between “starring” “featuring” “with” and “and”?	[ "When actors are signed to a role, their agent typically arranges for them to have a certain credit. Some will insist that it say \"Starring\", while others will reach an agreement with another title. Like \"Special Appearance By\", for example. Some insist upon top billing, others, if they can't justify top billin...	[ "* A \"Sell-By\" date tells the store how long to display the product for sale. You should buy the product before the date expires. It is a stock control system for the stores. * A \"Best By (or Before)\" date is recommended for best flavor or quality. It is not a purchase or safety date. It is a guarantee for the ...
Why is it if a stereo unit cannot decode a lossless audio format (e.g. flac) it can still receive lossless audio from another source (e.g. phone) and play it back at lossless quality?	[ "It doesn't support the codecs, at that point it's receiving the output of the phone, which is an analog output (in the case of the headphone/output jack) or a mutually supported digital output. To ELI5 analogy it: humans can't digest grass, but we can digest beef. Just because we are eating a cow that ate grass d...	[ "> I know that generally all life is thought to have a Last Universal Common Ancestor, but was that most likely a single individual? Not necessarily, it could well have been a population that shared genes. > Or is it more likely that early primordial life arose via multiple events, and therefore no matter how far ...
How long do landmines remain active?	[ "Every now and then here in Virginia they find ordinance from the Civil War that is still dangerous, although landmines weren't really invented yet." ]	[ "In Vietnam the Viet Cong would make booby traps and on them they would rub various poisons and feces on the damaging parts of the trap. Example is a Punji Stick: _URL_0_ Here is another sourced article on the topic for your read: _URL_1_" ]
Was the cause of admittance in asylums in the early 1900's really this extreme? Can someone please confirm?	[ "When I was doing some archival research at a former state hospital, the thing that made is tricky is that these sorts of claims are based on notes such as ‘reason for admittance’. For example, one person was listed as ‘kicked in the head by a horse’. Obviously, they weren’t admitted because they were kicked by a h...	[ "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...
Vision going black after standing fast	[ "Blood flows quickly out of the head and momentarily deprives your brain of oxygen. This is the cause of \"head rushes.\" However, if it's so extreme that your vision actually goes dark for a moment, you might want to consult a doctor." ]	[ "Im pretty sure its because you actually fell back asleep those moments it seems to go by in a flash... because you lost consciousness." ]
Before readily available contraceptives, how did the sexual relationship between married couples work?	[ "The most common form of natural conception was, somewhat unsurprisingly, simply not having sex at all. There's some evidence for withdrawal being used, but by and large 'stopping' (as demographic historians call it) was the main driver of fertility limitation. The period I'm referring to is Britain in the late nin...	[ "As a follow up, would the impact be lower in close-knit tribes of hunter gatherers with better social support than would be found in agriculturally-based civilizations with greater social stratification and more physical/socio-cultural barriers to group intimacy? And what role do certain beliefs regarding babies/s...
How did Hitler manage to train his tanks and planes, without notice?	[ "I don't know the answer to the general question, but one really amazing aspect of interwar Germany was their development of gliders, and their use of them for training new pilots. Gliders were not prohibited by the Treaty of Versailles and seen as a loophole. Incredibly, the German glider technology was mostly dev...	[ "If you're interested in how the Confederate government tried creating a positive image of itself in Great Britain as well as a negative image of the north, check out The Index. Henry Hotze was a Confederate agent in London and he created a newspaper dedicated to promoting the Confederacy and influencing public o...
How can a speaker play multiple sounds at once?	[ "The same way that your ear can hear multiple sounds at once. Combing multiple sound waves together results in a single new sound wave that can be created by a single speaker, and detected by a single eardrum." ]	[ "It has nothing to do with the file. It depends on whether or not the program says it's done with the file. Your word processor says \"hey I'm using this file\" for as long as it's open; apparently, your media player says it's done as soon as the song is loaded." ]
Please explain the difference between getting my oil changed and buying oil and adding it in?	[ "> So since that oil is new, why would I have to get my oil changed? Oil can be burned off but it also wears out. Old oil with bits of metal dust, burt oil leavings, etc. can build up within the oil still within your car. That needs to be cleaned out and the way to do that is drain out all the old oil then add new ...	[ "YouTube (and I assume other video websites) processes the uploaded videos. If you'd download a YT video, you'll find that it's not the same as the original file. If you would upload the file to a service that doesn't do any processing (such as cloud storage), then no matter how often you'd upload/download, the fil...
Why do the West always against Iran?	[ "A reminder to everybody that this is r/AskHistorians. As per [this subreddit's rules](_URL_0_): > we request that users in r/AskHistorians confine themselves to questions and discussions about events taking place prior to 20 years ago (1993)." ]	[ "Was Oliver North really just a scapegoat for the big fishes?" ]
Did the terms road/street/avenue/boulevard/etc ever refer to distinct phenomena, or were they always synonymous?	[ "They are not exactly synonymous. There is a distinction, especially in urban planning terminology. Road is just any type of traffic surface. Street is a road in a city or other built environment. Avenue is a street with trees on the sides. Boulevard is a large avenue with multiple lanes of traffic and trees on the...	[ "1 dimension) meet me at Bologna St. Needs more information. 2 dimensions) meet me at the corner of Bologna St. and Cheese St. Now you know you're in the general vicinity of where you need to be. 3 dimensions) meet me on the 3rd floor of the office building at the corner of Bologna St. and Cheese St. Great, now you...
How do those movie theatre vacuums work? The ones that don’t plug in and you just run it over the carpet?	[ "Wheels turn a drum with brushes, that moves trash into the body of the unit. No suction, just human powered rotating brushes." ]	[ "They use a wavelength of light that is cancer causing. Do you want to sit under a cancer causing light? Plus, they aren't all that effective to stop, say a sneeze from transmitting to another person. It takes some time to kill the germs." ]
What causes those crazy light shows when you press on your eyes?	[ "As a side note, I kinda already understand what causes the big green blob - the pressure on the optical nerve. But the actual patterns whooshing past is the big ELI5 here - how the hell does my brain end up interpreting it like that?! There's actual PATTERNS. Moving lights!" ]	[ "It's a consequence of general relativity. The two fundamental principles of GTOR are: > 1. Matter and energy curve space time. They shape the geometry of space time > 2. Objects move in the straights possible paths through this space time. Because space time is curved those lines are not straight. So this mean...
Why we put Q-tips in our ear, when it says on the box do not put in ear?	[ "Because it feels so good when you have that itch. The only kind of penetration I am willing to experience." ]	[ "They're preventing the liability of you burning your hand with the hot lid after microwaving. The drops of water below the lid that will inevitably be really hot - making the lid really hot. If they put the instruction to remove the lid, you can't sue them if you burn yourself thay way." ]
ELI 5: Why is China's undervalued currency such a huge/potential problem for the global economy?	[ "An undervalued currency allows China to export more than it would normally be able to. A \"cheap\" currency makes its goods cheaper overseas, crowding out exports from other countries. As a result, China holds a trade surplus (exports > imports) while many developed countries (especially the US) have a trade defic...	[ "Think of a rare baseball card. If there's only 10 of them in existence, then everyone would want them and they would be willing to trade hundreds of chocolate bars for it. Now think if they printed 990 more of that rare baseball card. Now everyone has one, and no one is willing to trade a chocolate bar for it." ]
What is ISIS and how did it start?	[ "In short, it's a jihadist group trying to gain power and control people. But it's not as organized as many people think, and for the most part it's just hateful, violent people with massive amounts of weapons. That's the Eli5 version." ]	[ "This CGP Grey video does a really good job of explaining it all. _URL_3_" ]
How far "up" do you need to be in order to see earth spin below you?	[ "All you need to do is drop a ball from tower and see that the ball does not fall vertically down, but tilted slightly Eastward. For a 1,000 meter tower at the equator, the deflection is about 70 cm. The effect, also known as the Coriolis effect is quite small and for any real tower experiment would be destroyed by...	[ "Get a protractor, tape or glue a straw to the straight edge, and tie a weighed down string to the middle. When you get on the plane, look down the straw at a star that you can easily pick out from the night sky (hope you're travelling at night!) and is viewable from both hemispheres, and mark where the string hang...
'Conservation of Energy' vs. Tempurpedic bed.	[ "> Where does the energy go? is the bed slowing charging up and will eventual explode like a spirit bomb? No, but it does get a teeeny-tiny bit warmer at the place of impact. Perhaps, if you drop a ball quickly hundreds of times, and it's heavy enough, you may be able to measure the temperature raise, something lik...	[ "Our brains didn't evolve with cars in mind. They evolved with, like, being hunted by a jaguar (or whatever) in mind. So your brain doesn't know what to do with a car. It thinks hey, we're sitting, our body's not really doing anything physical, there's very little activity or stimulus... this seems like a good time...
In your period of expertise, who is the most famous person in the world and who is the richest person in the world?	[ "Late Republican Rome? Easy. Caesar was the most famous and Crassus was the richest." ]	[ "The \"how\" is simple: HTML is just text, which you can write in any text editor. It didn't require special tools then, and still doesn't. The following is valid HTML which I'm writing off the top of my head in the Reddit editing box: < HTML > < HEAD > < TITLE > Web Page < /TITLE > < /HEAD > < BODY ...
AskHistorians Podcast 055 - History and Folklore	[ "Just subscribed to the podcast! Can't wait to take a listen while bussing to class :)" ]	[ "While you wait for a response to this specific question, you may be interested in [this previous answer](_URL_1_) from u/Iphikrates about the Trojan War and its historicity." ]
Why is binary code considered universal?	[ "At their most basic, computers are just a means to manipulate massive collections of switches. Those switches have two positions, on and off (1 and 0; true or false; you get the idea). Everything in computing, in the end, is down to these simple switches. What makes computers powerful is how fast they can perfor...	[ "You want to easily be able to identify where the missing texture is, and a purple/black checkerboard is pretty damn noticeable in 99% of cases. And once one person used it, some more started using it, and it kind of just self-standardised" ]
How does Aloe ease the heat of a sunburn?	[ "For the first part, aloe is mostly water that has a gel consistency, and in that gel there is 2 major components one of them being glycoproteins. They soothe pain and any inflammations and the second being polysacchrides which help to grow and repair the affected skin and any damages. *** not sure if I spelt the c...	[ "I think to best answer this question one should first take a moment and think about the life cycle of plants, how they disperse, and what a seedling needs to survive. Fats are an excellent source of stored energy. Many seeds are very rich in fats/oils which are used as storage energy for the embryo within the seed...
If water freezes at 0 degrees Celcius and ice melts at the same tempreature, what would happen if you took water and placed it in a place with exactly 0 degrees, no variations in temperature?	[ "If you add water to a zero degree environ, it will stay water. To freeze it you have to remove the latent heat of fusion. You have to continue to remove heat energy to get it to freeze into ice at zero degrees. Similar thing happens at the saturation point when water becomes steam, to it takes 1BTU/Lb of heat ener...	[ "Zero percent humidity means that there is no water in the air at all. So there are no water molecules anywhere in the air. 100% humidity means that the air contains as much water as it can possibly hold in the current conditions. If you get more then 100% humidity then you get fog and dew, possibly even rain or sn...
What are shepherd tones ?	[ "Shepard tone: sound loop made by a series of multiple sine waves rising one after another, eventually one of them reaches a point where it drops an octave, leaving the others to continue rising, they then follow the same pattern (drop an octave, rise again), creating the illusion of a never ending pitch increase. ...	[ "Basically you are hearing the muscular waves or [peristalisis](_URL_1_). More detailed explanation here at [Discovery Health](_URL_0_)." ]
The difference between the United Kingdom, England, and Great Britain.	[ "England is merely the country of England, which makes up about half of the island of Britain. Britain is England, Scotland and Wales (the 3 countries which share the island). Great Britain is these 3 countries plus various smaller surrounding islands (the Channel islands, Hebrides, Orknies etc). The United Kingdom...	[ "This CGP Grey video does a really good job of explaining it all. _URL_3_" ]
Is it true that Portugal regained its independence in 1640 thanks to revolting at the same time as Catalonia, and forcing Spain to choose which one to deal with and which one to let go?	[ "While we wait for other answers, I highly recommend reading an older similar question [Why did the Catalan Revolt during the 1640s and 1650s fail, but the simultaneously occurring Portuguese revolt succeed in reestablishing an independent state?](_URL_0_) answered by /u/kieslowskifan" ]	[ "While you're correct in saying that the Japanese didn't invade Macau, that's not to say that they didn't have a rather overbearing presence there. In 1943, they crossed into Macau in an attempt to capture a British cargo ship. The Macau police force fired on them, and had 20 killed. A couple of months later, Japan...
Why can we feel when someone is looking at us?	[ "1) Confirmation bias. 2) Sensing subconciously through odor, sound, vision." ]	[ "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." ]
after traumatic injury, why do scars develop, instead of healing without a trace?	[ "Avast ye! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: What is scar tissue and why does it develop? ](_URL_4_) ^(_14 comments_) 1. [Why do some people scar more than others? ](_URL_5_) ^(_6 comments_) 1. [ELI5: Why can't scars heal? ](_URL_9_) ^(_51 comments_) 1. [ELI5: What factors determ...	[ "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...
How is moonlight created?	[ "Moonlight is light from the Sun reflecting off the Moon. During a crescent or new moon you can see the dark portion of the Moon because of light reflected off the Earth, which then reflects off the Moon and comes back to us. That's called Earthshine. It still looks dark because after a couple reflections there's a...	[ "We streamed video from the moon during the Apollo Moon missions. Most simply, if you wanted a web cam, you could have the image sent from the Moon to the Earth as with Apollo, and then have the equipment on Earth send it out over the web. You would need more than one receiving station on Earth in order to get a co...
What does the US declaring war actually do?	[ "The United States government has enacted laws and powers that prevent the President of the United States from unilaterally declaring war without the approval of congress. To declare war, would give the full powers of the military all rights and access to wage war and use force against another nation. This has not ...	[ "Dick waving contest. Despite being overly brusque, this is pretty much it. Plus, if this time proves to be different, you're ready." ]
What is stopping naughty people creating a virus to hack Apple stuff?	[ "Nope. And in fact I'd wager that many viruses written for Apple based OS's was done entirely because they tried to make, \"we don't get viruses!\" an advertising pitch. There's no such thing as a completely impenetrable OS. Period. The reason why Apple computers, as a whole, get fewer is because they occupy a c...	[ "C'mon this is explainlikeimfive Linux - Legos - there are sets you can get or you can just build whatever you want. Might need a manual for some things. Windows - GI Joe - Everyone knows it and there are all kinds of cool accessories for it, but still a GI Joe in the end. Vulnerable to dogs and little ...
Assata Shakur once said, “Nobody in the world, nobody in history, has ever gotten their freedom by appealing to the moral sense of the people who were oppressing them.” Is this true?	[ "I don't recall any of the South American dictatorships of the 70s ending by war or external pressure. The case which I'm most familiar with, Uruguay, had been in a dictatorship since 1973, and in 1980 the military junta in power tried to give some legitimacy to its government, proposing a new constitution which w...	[ "If you know the full Hamiltonian for your system and the initial state, you in principle know how the system will evolve for all time. The time evolution is governed by the [time-dependent Schrodinger equation](_URL_0_). However you don't necessarily know what the results of measurements will be. For example, if y...
How do space probes keep their batteries from dying in the freezing cold temperatures of space?	[ "Heaters. In some cases it's purely electric; in some cases it's waste heat from a radioactive power source. As you've surmised, thermal management on spacecraft is a huge problem. A satellite facing the sun may be boiling hot on one side and freezing cold on the other - the heat must be channeled and controlled, t...	[ "Phil Plait and Walter Lyons can! > Assuming the video is real, I had a sneaky suspicion it had to do with the electric currents generated inside the cloud, the same currents that create lightning. Clouds can carry huge electric potentials — essentially, the ability to move charges around — and that stored energy ...
How did Eratosthenes figure out Earth is round and calculated earth circumference 2000 years ago?	[ "It’s also worth noting that Erastosthenes didn’t discover that the Earth is round...people had recognized the curvature of the Earth for a very long time. Ships disappear bottom first when going beyond the horizon, which wouldn’t happen if the Earth were flat...they’d simply continue shrinking until they are too s...	[ "I suggest reading David Fromkin's A Peace to End All Peace: The Fall of the Ottoman Empire and the Creation of the Modern Middle East. Mr. Fromkin describes how and why the Allies, through the Sykes-Picot agreement, drew the lines of the Middle East. He also points to imperial ambitions and Europe's lack of unders...
Why do auctioners speak so fast and so weirdly. I mean its hard for anyone to keep up or understand	[ "They do this to create a false sense of tension and time pressure. They pitch their voice up and speak loudly which emotionally signals excitement and they rush their words which implies you are running out of time and have to bid right now. Total scam, you should go to a few auctions and get used to the environme...	[ "There is a lot of work that goes into making the audio portion of the book. There are directors, producers, sound engineers and the person reading the book. Much like a movie there may be multiple “takes” of a chapter for various reasons. They also need to use studio time. All of these things add up. So while the...
Why do dextro and levo isomers show such different properties?	[ "For most purposes they will have the same properties, until they start interacting with other things that are isomers themselves. You can imagine two keys that are mirror images for each other that don’t fit in the same lock. It’s more or less the same thing going on, but scaled down to a very tiny size." ]	[ "Rule 1. First, examine at the atoms directly attached to the stereocenter of the compound. A substituent with a higher atomic number takes precedence over a substituent with a lower atomic number. _URL_0_" ]
Was there a name for the Battlefield in Ragnarök	[ "It is called \"Vigrid\" in modern Norwegian; [Wiki](_URL_0_) has an article on it. I always thought the etymology was 'vi', modern 've', English 'woe', and 'grid' meaning mercy, so \"No-Mercy Field\"; but apparently not." ]	[ "Hi, re your title question, check out this recent response from /u/Bernardito * [Is Wagner's Ride of the Valkyries being blasted from helicopter-mounted speakers during the Vietnam War an invention of Hollywood, or based in historical fact?](_URL_0_)" ]
How is CGI put into non-digitally filmed movies?	[ "They use a device called a [Film Recorder](_URL_0_) - modern film recorders simply expose a frame of film to a brightly backlit high res LCD screen, but previous generations would scan the picture onto the film with lasers" ]	[ "My guess? When you're dealing with a lot of makeup, prosthesis, special effects its easier to hide flaws. You can see acne under makeup in high def, you couldn't really see that back in the day. Just a guess." ]
The t-test conundrum in Neuroscience: a question about true significance	[ "I think you are confounded \"interchangeable\" with \"equal\". I can't comment on the paper you are citing, but I can comment on the relevant statistics. Remember that each treatment effect is not a point estimate but is actually characterized by a mean and standard error. The t-test is testing the hypothesis that...	[ "Well one way is by selected specific people for your study. The studied that showed evidence that vaccines caused autism actually dropped people from the study who had children not become autistic, found children who had family history of autism to include in the study, and kept the numbers small. Another way coul...
Do crickets coordinate their chirping with each other?	[ "Crickets, like all other insects, are cold-blooded. They take on the temperature of their surroundings. Many characteristics of cold-blooded animals, like the rate at which crickets chirp, or the speed at which ants walk, follow an equation called the Arrhenius equation. This equation describes the activation ener...	[ "ATC here checking in, the system you are talking about is a transponder and there are a ton of reasons for it to be turned off, in congested areas like an airport we have pilots squawk standby so that our radar displays don't get overcrowded, also when in a flight (multiple aircraft flying as one, think blue angel...
How do really basic free apps make money?	[ "If they don't have ads or in-app purchases and don't cost anything in the store then they're just free. They don't make money. People make things that don't make money for a lot of reasons: * Get their name out there * As something to show as a kind of resume * Just to help people * Because it's fun to make things...	[ "There are 2 types of touch screens, 1 of them works by touch, the other one is more complicated one. Phones use the more complicated solution, as this allows you to use a nice looking glass screen. Multiple times a second, your phone sends an electric signal on an layer behind the screen, starting in an corner, an...
Why do mirrors only reverse images horizontally?	[ "It doesn't actually reverse images horizontally, it reverses them front-to-back. However, when you see the image of a person facing you, you expect it to look like you would if you stepped forward and turned around. That rotation has the effect of flipping front-to-back and left-to-right, while leaving top and bot...	[ "Follow up question- how do people see me in the street: handsome mirror timaldinho or burn that photograph timaldinho?" ]
Why do spiders sometimes get snagged in the webs of other spiders? Wouldn't they be able to see a web and avoid it since they can spin webs themselves?	[ "Technically, Daddy Longlegs aren't actually spiders, they belong to an order called 'Opiliones', whereas spiders belong to the order Araneae. Both are arachnids, however. I'm not sure, but I don't think Daddy Longlegs, or Harvestmen as they're more commonly known, spin webs on any sort of regular basis. That said,...	[ "Take two computers and plug them into a router- you have now created a network. Take that little network and plug it into another router- now you have a bigger network. Now connect it to someone else's network and create a system that allows you to coordinate addressing computers on different networks. No imagine ...
How does solid matter stay in the together if it is being spun? Shouldn't relativistic effects tear all matter apart?	[ "You should read up about the [Ehrenfest paradox](_URL_0_). It is indeed true that if you spin solid objects fast enough they do indeed have to deform, eventually falling apart." ]	[ "Correct me if I'm wrong but AFAIK there is no accepted theory that rigorously motivates Einstein's GR, and the influence of mass distribution on the spacetime metric is axiomatic in the GR framework. i.e. the bending of spacetime by mass is a fundamental concept and there's no deeper explanation." ]
How different is the genetic material in one sperm from another sperm in the same ejaculation?	[ "According to a [Stanford study that mapped the genomes of 91 individual sperm cells from one man](_URL_0_), it can be quite different: > Each sperm in the sample underwent 23 recombination events, or mixing events. However, the study also showed that the degree of genetic mixing varied greatly between individual ...	[ "I don't know the exact terms off the top of my head, but as we age, we begin to stop producing as much of a protein that ensures our DNA strands are accurately copied by our RNA strands. This has the effect of sticking junk DNA to the end of the copies, which aggregate over time. Someone else may be able to elabor...
If a pure teaspoon of Botulism toxin is enough to kill a billion people, how are we injecting it into people's faces exactly?	[ "The toxin is extremely diluted. They also do their best to ensure it doesn't enter the bloodstream where it could potentially paralyze important organs. To give you an idea, a 100unit vial of Botox contains just .44 nano grams of botulism (44 hundred billionths of a gram). In teaspoons, that's .00000000000258...	[ "Mass production should actually make it easier - if a specific type of pepper varies in hotness, then it's hard to say what one pepper will taste like. But 10,000 of those peppers, all mixed up, will taste about like the average of all their hotness-es. So you'd just plan for that, I'd think." ]
Did paper airplanes exist before real planes,and if they did are todays planes inspired after those?	[ "[Here](_URL_0_) are a couple older posts/answers about this." ]	[ "Your asking essentially the chicken or the egg. Example, Did you stomach evolove first and create your brain and extremites to feed it. Or did your brain grow your stomach to power it. Har to say, as without something to feed the stomach, we would have no stomch. Without the brain to run everything, we wouldn't ha...
If the whole of the salt content in all the world's oceans were to form 1 solid chunk, how large would it be?	[ "Well, according to [Wikipedia](_URL_0_), there are approximately 1.3 billion cubic km of water on the planet. Some conversions, density figures, approximations, and stoichiometry give us the following: (1.3x10^9 km^3 ) x (1000^3 m^3 /km^3 ) x (1000L/m^3 ) x (0.035kg NaCl/L H20) x (1000g/kg) x (1cm^3 /2.165g) x (10...	[ "For what it's worth, NASA did print it out (or someone did). The (almost) full mural was hanging out at the AAS conference in Seattle a couple weeks ago (AAS is the biggest conference of astronomers every year). It was printed at 240 pixels per inch and was 25 feet long by 7.5 feet tall ([pic with info](_URL_0_)...
During World War II, were trhere any accounts of people on the ground being accidentally killed by 50-cal rounds being fired from bombers defending themselves from fighters?	[ "A while back [I answered a similar question, about civilians hit by falling flak.](_URL_0_) While it's not entirely the same, I think it's appropriate." ]	[ "Hard to say exactly as they don't exactly record how often songs are sung. That said Panzerlied was a song that's supposed to be specific to the Panzerwaffe arm, which was always only a small fraction of the Wermacht. It consisted of around 20 Divisions at any given time out of an army of over a hundred Divisions....
Why are we able to physically feel pain or other sensations when dreaming?	[ "Is this a common thing? I don't think I've ever felt pain in a dream." ]	[ "Not a neurologist here, but I had read certain articles way back that explain our learning process. It was sort of like: we learn a certain thing while we are conscious, but this certain thing we learned is only stored as short term memory while we are conscious. The brain processes this information during sleep t...
Why do we laugh when other people get hurt	[ "It may be partially from our personal experiences with those types of situations. Since we know the feeling of embarrassment that comes from falling off a bike, we can relate to that and find humor when seeing it from another person's perspective. For example, a video depicting a guy breaking his leg in a skatebo...	[ "suconsciously, our minds don't like processing real observations of bodies being violently altered." ]
If someone is wrongfully imprisoned for a period of time and then released after proven innocent, how is their compensation calculated?	[ "Depends on the state. [Each state has different statutes governing this] (_URL_0_). Also, several states have no statutes at all, meaning that if you get wrongfully convinced there, you have no automatic right to recourse. I believe (but am not 100% on it) that you can take the state to civil court, but obviously,...	[ "Go to a new area of Australia (or wherever). Comb one acre very carefully, cataloging every species. Figure out how many new species there are. Do this in a few different places, figure out about how many new species there are in general, and extrapolate." ]
How do we know/measure the distance of objects in space to us? Like how do we know that one Star is 5 light years and another is 500?	[ "There is a ladder of thing we use to measure distances. Relatively close things, we can use parallax to measure. Look at something in the sky when we are in the summer, then exactly half the year later look again. It will be in a slightly different spot. How slightly is determined by how far away it is. For object...	[ "We dont, but if you would have an item that gathered carbon out of the atmosphere for the last few thousands years you could check how the ratio was changing. We use very old trees to do that, the oldest living one is around 6000 years old and It's a bristlecone pine. Also antarctic ice could be used to further an...
Can lightning happen on the surface of the sun?	[ "As the surface is composed of conductive plasma instead of insulating air, it is unlikely that a charge difference great enough to produce lightning could exist in the first place. Any charge on or near the surface would be 'grounded' to all the areas around it immediately instead of building up to a large dischar...	[ "You're right to be confused. It is 100% wrong as depicted in the movie, and a lot of people of wondered about why they made such a grave error considering the rest of the movie was somewhat realistic. It is likely that the reason this happens in the movie is that it makes things more dramatic. Artistic license i...
Why do some pills have 2 different colored sides?	[ "Each pill has to be identifiable from the other, according to EU/US law. If they are using that specific cast, they use different color coding to tell one from the other" ]	[ "Not sure but I've seen them pressed more often when I order for multiple people. I think it's just a shorthand so the customer knows which drink is which and which box has which burger. So when my mom orders for me and my sister and herself she can easily give my me coke, my sister her root beer, etc.." ]
how someone can be sentenced for 900+ years?	[ "To avoid any chance of parole for them. If this person was only sentenced once, and got cleared in some way, they'd be free. This forces them to get cleared many times, which isn't likely to happen so it stops people who shouldn't be freed from being freed." ]	[ "u/ToxiClay is correct and there is a [really good episode of Radiolab](_URL_0_) that tells her story, including interviews with the patient and her doctor. They also go a bit into the answer to your question. Worth a listen." ]
Why is it scary when kids sing or laugh or say nursery rhymes in horror movies/games?	[ "Generally, it's done in a minor key where the tune is altered, so anything can be spoopy when done that way (Have you seen the Teletubby episode in black and white that plays a Joy Division Song over it?). Also, one of the early films to do this was Nightmare on Elm Street where kids are jumping rope and singing ...	[ "The cochlea in each of your ears is a spiralling organ that contains a bunch of tiny little \"hairs.\" When sound is transmitted from the air into your cochlea, it travels through the cochlea and depresses hairs corresponding to different frequencies. [The hairs further and further in the spiral](_URL_0_) corresp...
What is happening when the "wind is knocked out of you?"	[ "The solar plexus is a nerve ganglia - a large collection of nerves that handle autonomus (automatic) functions like breathing, that can continue while a person is asleep/unconscious. it's located just below the sternum (breast bone) - in the valley between the ribs. Being hit here somehow disrupts the solar plexus...	[ "Ok, so in the chest cavity between the ribs and lungs there is space, which normally has lower than the atmospheric pressure. This allows the lungs to expand and fill with air when we open our airways and use our breathing muscles. If there is communication between this space and the outside (from a stab wound etc...
How do the big torrent uploaders like Yify, EZTV, etc, not get caught?	[ "There can be many reasons: - hiding behind a VPN or TOR or another proxy, or all of those; remember that there still are countries where piracy is not regulated by law - initial seeding from a remote server - actually living in a country with no laws against piracy - all of the above I also doubt that they are *th...	[ "I use TPB for a couple reasons. Number one is nostalgia. Number two is respect. They've been around for 10(?) years or so, name another pirating platform team that has faced the level of pressure TPB has...Mega, maybe? These guys are serving prison time and still running TPB. They've made plenty money and could ha...
Software Architecture	[ "Software is built of various logic and data components that interact with each other. Architecture design is determining at a very high level what these components should be, what they should do and how they should talk to each other." ]	[ "How consciousness maps to its host \"hardware\" is one of the big questions of neuroscience." ]
Why does travel in a bus/train make me feel tired?	[ "I believe it's from the constant adjustments your body has to make from being bumped around. You never get the opportunity to sit still like you would on a couch." ]	[ "Read Nightwatch by Sergei Lukyanenko. It deosn't give an actual reason, but the made up one is pretty cool. Russian distopic modern fantasy. Seriously though, my guess would be either: 1. Extra energy (I sometimes just start running places too.) 2. Seeing a little critter or something that you don't." ]
Why is there soo much fluctuations in pricing for flight tickets ?	[ "The goal of any airline is to get as many bodies in seats as possible. The price doesn't really matter to them. But it makes them very mad to fly planes that are half empty. So they start out with cheap cheap fares, if you book way in advance, and as you get closer to the flight date, the price goes up. The th...	[ "The business cycle. This is just how capitalism works--it goes from boom to bust and back. Actual hard answers are complicated bits of economics that are beyond an ELI5." ]
If I am seeing a full moon, does someone a few timezones away see a full moon too?	[ "Yes the moon will be full (or close enough to it) for everyone on earth. The full moon happens with the sun and the moon are on opposite sides of the earth, so that the side of the moon facing the earth is illuminated by the sun. Fun fact: the side of the moon facing earth is always the same side, since the moon r...	[ "Nice work, you've discovered Olbers' Paradox :) This was a much-discussed problem in antiquity. _URL_0_ Take a read of the wiki page, it's very good at explaining. And ask away if there is more you want to know." ]
Is the world more or less violent now than it has been in the last 100 years?	[ "Much safer. [Steven Pinker explains this very well.](_URL_0_)." ]	[ "I have a question for you. Do you want the version that is super, super long and includes a write-up on what actually went down at Munich, and the subsequent responses back and forth? Or do you want the shorter version that only talks about media coverage of the incident and how it changed things?" ]
How can an image not be distorted when it is magnified by a non-integral (1.5x instead of 2x) value?	[ "There are algorithms that correct for this, one such way is to interpolate values between where the pixels would be. So lets say you had a red pixel next to a black one, the interpolated value would be a dark red. This makes the picture look blurry instead of pixelated." ]	[ "Basically, you have to be weaker if you want the kind of fine muscle control we have. Chimps and gorillas physically could not do the kinds of things we can do with our hands - sculpture, art, writing, etc. - because of the way their muscles are attached to their bones. They have better leverage because their an...
One in the hand is worth two in the bush	[ "One bird in the hand (one you have already caught) is better than two in the bush (that you haven't caught yet). It is better to have one of something than the remote potential for getting two of them." ]	[ "I would personally give my left arm to be ambidextrous." ]
How do you "waste water"?	[ "While it is extremely difficult to actually destroy water, what you're doing is wasting usable water. Sure, it just re-enters the water cycle the cycle is not instantaneous. So if the water cycle dumps a million gallons of usable water in your area every year, and you're using 1.5 million gallons every year... y...	[ "There was the [Archimedes Screw](_URL_0_), which has been around since at least the 3rd Century BCE. Also, you should read the first couple sections on fountains, [here], (_URL_1_) where it explains how Romans used gravity to create pressure down the line. Finally, I know the Mayans created water pressure by chann...
Why do juices taste better after shaking them, even juices without pulp?	[ "Unless you're getting it right from the fruit, most juice is pasteurized. (Both from concentrate, and not). This basically kills the flavour, so an additive is put in. This typically separates when sitting, so shaking disperses the flavour additive evenly throughout, making it taste 'better' than if it'd been sitt...	[ "I used to work in a lab where we had to mix bulk samples before sampling. For what you are doing, grab the box by opposite corners and rotate while rotating the corners hand to hand. So the motion is the same as if you were spinning it through the axis of the corners while rotating the corners themselves. Works be...
How does ATP synthase rotate?	[ "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...	[ "The device isn't manufactured to the strict tolerances needed to maintain the same rate, because there's no reason to do so. So anything from the charge in your battery, to the heat of the environment, can introduce some 'wiggle room' into the mechanism. Since it would take extra expense to eliminate this, and sin...
The Berlin Airlift moved vast amounts of materiel into the city. What happened to the waste the city produced?	[ "West Berlin had plenty of marshy and other marginal areas that could be used for a landfill, especially in an era when incineration of solid waste substantially reduced the volume (and helped reduce the need for coal). Sewer pipes continued to run to treatment facilities in East Berlin. Much later, in the era of t...	[ "Hooray, I'm useful. I used to work at the Port of Baltimore. My job was silly, and ultimately useless but it did let me travel all over the port and see how things work there. We had a company that leased out a fairly large parking lot that did nothing but ship used cars to Africa. Theres a high demand for cars a...
Does nutritional research vary so much because our species is evolving to counteract our diets or do we just know so little about nutrition?	[ "We know very little about nutrition. It is a remarkably complicated subject with some really advanced chemistry. Almost all of our advice is empirical, people tried it and it worked, they figured out how much of x people needed on average because people were getting sick without it. Evolution takes place over hund...	[ "Hi OP, this is a cultural question, so it would greatly assist anyone considering answering if you could specify which culture you're asking about. For example, the name of a cultural group / country / geographic region, plus a rough time period. Otherwise, this question is simply too broad, as it encompasses almo...
What is BMI? And why is (or isn't) it important?	[ "It's a quick and cheap measurement of fitness (not healthiness), better measurements include bioelectrical impedance measurements of body fat. This is where a tiny electrical signal is sent through you, and knowing your height and age it can calculate your fat and muscle percentages because of their different resi...	[ "I could try to explain it to you, but this video is all you really need: _URL_9_" ]
Can You Contain a Anti-proton plasma Using Normal Matter?	[ "The issue is that the electromagnetic force from the electrons to anti-protons is too weak. On larger distances, the atom is neutral, because of the positive nucleus. It will only allow for distances on the scale of atoms. Because the plasma particles are whizzing around, they can still hit the normal protons. Not...	[ "The Ghostbusters infamous backpacks are supposed to be \"positron colliders\". When positrons collide with electrons, they either destroy them or scatter, they dont create magic lassos." ]
Has the earth's gravity increased in any significant manner since the emergence of life?	[ "The short answer is no, there has been no substantial change. The mass of the earth is on the order of 10^24 kg, so for even a 1% change in gravitation potential you would need a change in the mass on the order of 10^22 kg, which is a huge amount of matter and far more (in my estimation) than catching space debr...	[ "Because we stand upright. Our large brains mean that we have more cognitive high level functioning. However, when humans began to move to an upright standing position our pelvis needed to rotate and become narrower, this combined with a larger skull means that our babies must be born younger and less developed. He...
What is a cookie (internet, not delicious food item)?	[ "It's a small piece of data that a website sends you and you store on your computer. Generally used to track something from the server about you. Good examples of this might be authentication cookies. The server sends you some information that proves to the server that you're logged in and what account you're logge...	[ "Code on the page can automatically load another site in your current window or a new one. You're experiencing abuse of a this feature but it's often a good thing, like being taken to a confirmation page after your credit card purchase has gone through." ]
How does a company know if their TV commercial has been successful?	[ "It depends. Some commercials that have phone numbers use a special one just for the commercial. Thus, any calls you get to that number are attributable directly to the commercial For others, they will look at purchase behavior before and after the commercial airs. If it goes up, it can be assumed to be due to the ...	[ "They don’t. However polling, streaming services, and in home devices like the Nielsen program allow statistics to be computed and extrapolated to the larger population set." ]
Why don't things burn instantly?	[ "It needs to heat up to the point where it has enough energy to combust. Also not everything is very flammable" ]	[ "Heat transfer can be complicated, but in simple cases you can think of the rate to be proportional to the difference in temperature. So as the piece of glass warms, it will warm slower and slower as it approaches the temperature of the fire." ]
Why streaming "pirate" sites are mostly hosted in russia?	[ "The Russian state largely does not regulate the internet. Cybercrime basically goes unpoliced. While the lack of concern about the internet certainly exists beyond him within the Russian state, Vladimir Putin has referred to the internet as a \"CIA experiment\" which should give you some idea of how important it i...	[ "Country specific ones follow the laws of that country. You can search for Tibet freedom on _URL_0_. but not _URL_1_ or Google.can Google was given a choice by Chinese gov. Either you make the search engine follow our rules, or you don't do business in China at all and China blocks _URL_2_ entirely" ]
What were the main consequences of the 1683 Battle of Vienna?	[ "This is the kind of question which totally sounds like something you need to answer on a take-home test." ]	[ "Could you perhaps present us with your original source so we can see what the author writes about it? I think I know the answer, but I would like to know what exactly the author wrote. Also, could you remove the bonus question? We do not allow discussions of events after 1993." ]

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