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vblagoje

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lfqa

like 16

{ "a_id": [ "doc42pf", "doc4l5s" ], "score": [ 4, 2 ], "text": [ "Think of it as balls and buckets. It takes energy to kick a ball into a bucket, and it takes energy to remove a ball from a bucket, but unless someone does something a ball outside a bucket will stay out, and if the ball is in it will stay in. Each bucket is a bit, and it's state (0 or 1) will be determined by whether or not it has a ball. You sculpt your stored data by plucking balls out of buckets.\n\nThe balls are electrons and the buckets are just a metaphor for some quantum behavior I've never understood, but the ball & bucket analogy helps me understand.", "Voltage is just one of many ways to represent a 1 and a 0. Flash drives use another representation.\n\nYer not alone in askin', and kind strangers have explained:\n\n1. [ELI5: How does flash memory work (on the microscopic level)? ](_URL_2_)\n1. [ELI5: How does flash memory work? ](_URL_1_)\n1. [ELI5: What happens inside of a USB flash drive that allows it to retain the new/altered data even when it's not plugged in? ](_URL_0_)\n\n" ] }

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[ [], [ "https://www.reddit.com/r/explainlikeimfive/comments/491s71/eli5_what_happens_inside_of_a_usb_flash_drive/", "https://www.reddit.com/r/explainlikeimfive/comments/2wjkwt/eli5_how_does_flash_memory_work/", "https://www.reddit.com/r/explainlikeimfive/comments/1ezoyf/eli5_how_does_flash_memory_work_on_the/" ] ]

{ "a_id": [ "ck3pczg", "ck3pe36", "ck3qd3p", "ck3sn6j", "ck3syhs", "ck3syli", "ck3vl2n", "ck3wf6e", "ck3z5dz", "ck40m7n", "ck43e0s", "ck468fm", "ck4893o", "ck48lv8", "ck49h64", "ck4au8m", "ck4beer" ], "score": [ 76, 324, 3, 11, 7, 6, 48, 3, 6, 4, 2, 2, 4, 2, 2, 2, 5 ], "text": [ "You might be able to.\n\nWouldn't recommend it.\n\nScrewing around with the mail service in pretty much any way is a federal offense. I'm wondering if it might be worth a charge of mail fraud; IANAL so it's not easy to be sure.\n\nMail fraud is *big* prison time, though, if that's what they'd charge you with.", "You can. I have a friend who got caught, and was banned from the Postal Service for several years. ", "What would determine if they deliver to the addressee as postage due versus returning it to the sender?", "Basically this is ~~mail fraud, at best they get the letter no one is the wiser. At worst, they open an investigation and you go to jail for [20 years](_URL_0_) because your friend ratted you out. There is a grey area where your friend is charged the postage, but i am pretty sure this puts them on a list if it happens more than once.~~ a [fine](_URL_1_).\n\nEdited- left original text added a new link.", "The effort of setting up this scheme, so that the intended recipient of your letter will understand that the letter is actually intended for him or her, even though his or her address appears as a return address rather than as an actual address, outweighs the very minor saving of postage. Also bear in mind, it is very easy to send email for most purposes. When you are sending a letter through the mail, it is probably for some purpose that is important enough that you do not want to screw up. So why take chances?", "You can. A fellow I knew tried this once and it worked.\n\nOther than the fact that it's mail fraud, I can't see any reason.", "I once accidentally put my address for the send to and the irs on the sent from. I had a demand for filing my tax return and hit the deadline. It ended up getting sent late because of it. \n\nI sent the first envelope with an \"oops I fucked up\" letter. I was working 70 hour weeks doing manual labor. I was just tired and made a mistake. I'm sure they got a good laugh about it in the office. They didn't charge any fees or anything. \n\nI think that they're real human beings in the irs, not some soulless entity. Just be honest and don't cheat on your taxes. \n\nAs far as your question, is a 27 cent stamp worth possible fraud charges? It seems like a really stupid idea", "They also don't like it when you attach the stamp to the letter with a piece of tape that covers the stamp.", "Have done this \"for educational purposes\" and it worked.... However consider. If the return address is in New York and you drop it off at a post office in California...", "In the 80's a pen pal and I used to coat a stamp with a very thin layer of Elmer's Glue. After you get the letter you can soak the postmarked glue off the stamp and the stamp from the envelope too. Re-apply and re-glue and you're all set.", "You can do it, but I have heard of several things happening. They might send it back to the return address; forward it to the addressee, postage due; or it might get chucked into some USPS black hole. I have also heard stories of people being subject to criminal charges, or at least threatened with them. My experience has been that they treat it differently depending on how far it is being sent. YMMV.", "Easy solution in germany: \n\nThey will deliver your letter to the given address but ask for the cost of the stamp (plus an additional fee). If the recipient refuses to accept the letter they will send it back to the sender and again ask for the fee(s).\n\nIf there is no sender noted down (or the sender denies any knowledge) they are allowed to open the letter and try to identify a sender / recipient.\n\nSeems so obvious?!", "You can. Friend of mine decided to see if it worked and I got a letter with return to sender in the mail, even though she sent it. She just reversed the addresses.", "Why should we buy postage stamps? We can make our own!\nI believe in swordfish.", "Tried this once, and not surprisingly, they black-holed it. One look and they pretty much know that a letter in a mailbox in Paducah with no stamp and a return address in Idaho is bullshit.", "Because mail carriers are not stupid. ", "When I was a kid, my friend wrote a letter to me. I read it, put my reply in the envelope and wrote \"not at this address, return to sender\". \n\nIt made it back to them. Thinking back, no clue why I didn't just ask my mom for a stamp. 7 year olds do odd things I guess. " ] }

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[ [], [], [], [ "http://en.wikipedia.org/wiki/Mail_and_wire_fraud#Mail", "http://www.law.cornell.edu/uscode/text/18/1725" ], [], [], [], [], [], [], [], [], [], [], [], [], [] ]

{ "a_id": [ "crti4if", "crtk24t" ], "score": [ 2, 3 ], "text": [ "Mega is encrypted, so if I put a movie file up there that is illegal there is no way for someone to know other than to actually download the file and check. And of course if you lock the file so only you or a select few can access it there is no way to know what it is. On Mega’s end they can't actually see what the file is. This means Mega can't easily take down copyrighted material uploaded to its site, and as a result piracy can flourish on it. This is by design.\n\nMega also gives you 50gigs of free space with an account, allowing you to throw up more and larger files than on Medafire. \n\nThe Pirate Bay does not host files they only hand you magnet links to torrents. Instead of downloading the file from Pirate Bay you download it from everyone else on the internet who has that file and is actively seeding it. This means its almost impossible to shut a torrent down. \n\nMediafire is none of these things so if you throw up a movie file to them they can see what it is and remove it, and its more likely they will be requested to do so by the copyright holder. \n", "I use TPB for a couple reasons. Number one is nostalgia. \nNumber 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 have gotten out years ago, but they continue to risk their freedom for us(and more money).\n\nTL;DR 1. Nostalgia 2. Much Respect." ] }

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{ "a_id": [ "cxvloye" ], "score": [ 2 ], "text": [ "Depends on how you define \"civilized\" and \"nation\".\n6th edition of *Longman Dictionary of Contemporary English* defines \"civilized\" as: \"1. a civilized society is well organized and developed, and has fair laws and customs\". In historical use, from what I remember, a civilized state has the following characteristics:\n\n* Urban city centers\n\n* A form of symbolic writing\n\n* An organized government and a taxation system\n\nEgyptians had hieroglyphs as early as around 3 200 B.C, if I recall correctly. However, Egypt has not been existed continuously as it's own nation, the Persians conquered it around 525 B.C, Alexander the Great conquered Egypt (and pretty much everything else while at it, too) from the Persians, and the Hellenes were driven out after the war between Octavian, who would later be known as *Augustus Caesar*, and Marcus Antonius, or Mark Anthony, as his name has been anglicized, and finally, the Arabs conquered Egypt from the Eastern Roman Empire. \n\nAs far as I remember, the Kurds have never been independent, so I am not sure if they really count.\n\n Meanwhile, in the Far East, China has had, according to folklore and tradition, dynasties, and thus governments, and thus taxation, since 22nd century B.C. Written language in China may date back even to [7th millenium B.C] (_URL_0_), but the evidence can be disputed as an anomaly. China, while it has been conquered, has never had it's ethnicity, culture and government system changed much, as far as I know, so I would say that China is the oldest civilization which still exists. " ] }

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[ [ "http://news.bbc.co.uk/2/hi/science/nature/2956925.stm" ] ]

{ "a_id": [ "ct8y8so" ], "score": [ 4 ], "text": [ "St Andrews was unusual in that between 1552 and 1805 they used rabbits. There was a financial incentive for this, because rabbiting was a huge industry when every part of a rabbit had a use and there was always an increasing supply. This benefitted both the landlords who sold on the rabbits and the commoners who caught them - both received financial rewards - but the golf course would have held little revenue for commoners until tourism as an industry developed as we know it today.\n\nMass killing the rabbits was legalised in 1805, as the tourist golfer population and their interest in st andrews was rising. Golf itself was being standardised, and rabbits left too many of their own holes in the course to disturb matches. There was a 16 year struggle between the two sides until 1821 when the foundations for an established course were laid out. \n\nBecause the golf course is known to be over 500 years old, but rabbits were permitted in 1552, I would assume that rabbits were already being used and permission was granted as it was a difficult practice to curb (as is often the way) but it would otherwise have been livestock, probably sheep. Modern grass maintenance arrived in the mid-victorian era when the basic lawnmower was invented, in 1830, so I would again assumed livestock were used until later in the 18th century when St Andrews would have been able to purchase one.\n\nI was able to find [this internet history](_URL_0_) for quick reading, but the 'definitive history' recommended is St Andrews, The Evolution of the Old Course: The Impact on Golf of Time, Tradition and Technology by Scott MacPherson. Hope this was helpful." ] }

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[ [ "http://www.scottishgolfhistory.org/oldest-golf-sites/1574-st-andrews/" ] ]

{ "a_id": [ "czryy2h", "czs1xb5", "czs2091", "czsa5e3", "czsigh8", "czt772m" ], "score": [ 14, 60, 11, 7, 2, 3 ], "text": [ "Hi, quick moderator request for you: could you remove the following section?\n\n > In an alternate world where the USA went communist and Russia went free-market capitalist, would history have leaned more in Russia's favor or not? Would Russian culture ever have striven for free-market capitalism in the first place?\n\nThis subreddit does not permit [speculation on possible alternative pasts](_URL_0_). Rather, those questions would be more suited to one of the counterfactual subs like /r/HistoryWhatif.\n\nThanks!", "In his book, *Predicting Politics*, political scientist Bruce Bueno de Mesquita simulates the Cold War as a battle over ideology between different countries. He allows the *salience* of foreign policy to vary randomly in each run of the simulation; military, economic, and demographic capabilities are set at the outset and then vary over time due to conflict or cooperation between states. Anyway, what his model finds is that most of the time, the USSR more or less gives in and moves to the US position on international ideology. Still, in at least a quarter of cases, the opposite happens (usually because the US cannot assemble a coalition that cares about ideology and it suffers costs from resisting a more-powerful Soviet bloc alone). I'm not entirely persuaded by the simulations, but the model has been reasonably accurate as a forecasting tool, so it's not unreasonable to suppose that if Europe and Japan went to the far left, the US would basically withdraw from intense competition with the Soviet Union, leaving it to set the international agenda. Political science is probably as close to counterfactual history as you'll get, since all cause-effect statements necessarily include counterfactuals (e.g. if A makes B more likely, then B must be less likely absent A). ", "Sadly I have few sources on hand, I'll be writing from memory here, the only source I have on hand is \"*The Penguin History of Russia*\", a relic from when I studied the Russians back in Uni.\n\nAs with most historical conjecture, it depends. Russia would have needed some remarkable stroke of luck to overcome America, something like a Civil War in the states, some Diplomatic Coup or a successful one sided nuclear strike. Russia couldn't compete with America conventionally because of one extremely pertinent point.\n\nRussia's Navy wasn't good enough.\n\nI know it's really Mahanian of me, but Navies are the prinicpal way though which international power is asserted. Without a Navy Russian Power was limited to where their men could march, further limited by the supply trains needed to march/fight wherever they were projecting their power. The Americans could fight anywhere, almost any time.\n\nRussia posed a threat to Europe, but not America. Economically there was never any completion, diplomatically the Russians definitely made gains, but not enough to tip the global balance of power.\n\nSo, in short, the Russian economy and geography stymied any potential attempts to match American conventional power, only though unconventional means could the Russians hope to defeat America.", "Related question: did many Western leaders see the west as having an advantage over the Communist world?\n\nLooking back, it's pretty easy to see how weak the Communist world was. Did anybody see it that way at the time?\n\n\n\nMy very uninformed understanding is that most leaders saw the two sides as equal, or the Communists were winning.", "Depends when exactly you're talking about. Right after the war ended the European allies and Germany were smashed, and yet Russia's military-industrial situation was the best it had ever been. The atomic bomb however was a severe deterrent, so without having to worry about it the Russians could have led an offensive westwards. Unfortunately for them, over the long term the Soviet economy and military didn't age well, and according to sources like Viktor Suvorov, in his analysis of the internal workings of the red army, in the 1960s Soviet officers worried they couldn't beat the West German Bundeswehr, never mind a combined NATO force. In their view the second world war had been their zenith. \n\nThe USSR could also have gone on, like North Korea has, if not for the fact they chose to deStalinise and gradually thereafter loosen the authority and control the Communist party had on everything. Keep in mind the invasion of Czechoslovakia in 1968 was because orthodox Communists feared that a free press was more dangerous to the Soviet model than starvation or war. In his book on the invasion (The Liberators) Suvorov makes the point, citing a conversation he had at the time, that since the red army was essential to the harvest, deploying the army abroad that late into the year risked starvation. So in that context it makes perfect sense that the progressive reforms Gorbachev launched were the same sort his predecessors had put down with tanks, and the orthodox Communists had been right that such would be fatal to the system. \n\nBottom line is that the Soviets were unlikely to have won, especially outright, especially given atomic weapons, but they certainly could still be alive today, prolonging the conflict for a very long time, if not for their internal politics unfolding as it did. ", "The better question is whether anyone actually \"won\" the Cold War, or if one actually existed to begin with.\n\nNote that while the Soviet Union has collapsed Russia still exists and still retains a fair number of warheads from the Cold War; and is even expanding the deployment of its delivery systems such as the recent completion of three new ballistic missile submarines. Russia moreover was never \"defeated\" in the same way as Nazi Germany or Imperial Japan - not a single foreign soldier was involved in its collapse; and it can be quite convincingly argued not a single diplomatic or economic move made by the West in fact contributed to the \"collapse\" - everything was decided by the people and leadership of the USSR itself.\n\nWhat has changed is Russia's direct control over Ukraine and other states within the USSR (which has now devolved to partial control), and their indirect control over Central Europe via the Warsaw Pact (which they themselves allowed to be relinquished anyway - Gorbachev could have sent in the tanks any time like the Soviets did in the 1950s. He didn't.). \n\nBut the Cold War wasn't supposed to be about fighting over Central Europe or Ukraine - it was supposedly an ideological conflict between \"capitalism\" and \"communism\". The latter in fact still exists - indeed it had always existed in the West in the form of \"socialist\" movements and still exists in China. Very few people want to admit this though because it will make all of the US chest-beating for the past 20 years about the Cold War \"victory\" seem rather hollow." ] }

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[ [ "https://www.reddit.com/r/AskHistorians/wiki/rules#wiki_is_this_the_right_place_for_your_question.3F" ], [], [], [], [], [] ]

{ "a_id": [ "e1grc2z", "e1grg3r", "e1gsqhl", "e1gxmru", "e1h4v8s" ], "score": [ 2, 10, 3, 2, 2 ], "text": [ "Why would you expect otherwise? The curve has to peter out somewhere.", "It's likely Mt. Everest is near to the largest size mountain earth will support. A larger mountain is more massive, which puts a strain on the material at its base. They deform the plates they sit upon, more mass will further the deformation. And depending on height and climate, can promote glacial development, which it has been theorized to cause vigorous erosion limiting total height. ", "It'll be impossible to find a complete list, but there are at least 127 mountains over 7000m. It gets even harder for the 6000m peaks, but depending on who you ask, there are over a thousand of them in Asia alone.\n\nSo 14 isn't a lot; it easily could have been zero. In fact, for most of Earth's history it probably *was* zero and the only time it's ever not zero is when there's \"recently\" been a continental collision. After all, those 14 are all in the same mountain range. ", "Hawaii's volcanoes are taller ... if you count from the sea floor.\nThe crust can support it, at least in the center of a plate. Maybe if the mountains form at a region where the plates are smashing together, its weaker?", "There's room for one big exception in this discussion, a controversial one, and that's Mauna Kea, which measures something like 10,000 meters from its base, 6000 meters beneath the sea.\n\nMauna Kea appears to be very close to the theoretical maximum height a mountain can reach. Go much bigger and the mountain's own structure cannot support its own mass. I think it actually *melts* at the base as a result of the absurd pressures, does it not?" ] }

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{ "a_id": [ "da7484f", "da74dc3", "da75gp6", "da79yga" ], "score": [ 19, 3, 7, 2 ], "text": [ "So you have this balloon hooked up to an air compressor. Youre watching this and you see its slowly getting bigger. We know its getting bigger because if we draw a bunch of dots on the balloon with sharpie, you notice all the dots are getting farther from eachother.\n\nThe big crunch says that this air compressor will turn off, or atleast slow down enough that air is escaping faster than entering. \n\nIf the air compressor is currently on, yes its possible that it will turn off, but without other knowledge it makes more sense that it will keep inflating.", "Observation is the main thing. Scientists can see that the universe is expanding. While it is possible that the expansion is temporary and it will reverse itself, that would first require the expansion to slow down. We observe the opposite and the rate of expansion is increasing. Since the only force we know of which could cause the expansion or crunch is gravity, the evidence shows the gravitational pull of all the matter (both regular and dark) in the universe on itself just isn't strong enough to bring everything back together. The more the universe expands, the weaker the gravitational pull will get, so there's no known force that will cause a reversal.", "Because it doesn't fit the the evidence.\n\nWe believe the universe is expanding, because the farther away distant galaxies are, the faster they are moving away from us.\n\nWe believe the expansion is accelerating, because certain types of supernovae are dimmer than we expect, indicating their light travels a greater distance than a non-accelerating universe would indicate.\n\nIf the universe is expanding, and that expansion is accelerating, that makes a Big Crunch more difficult.", "1: the universe is expanding. We know this because there are a few stellar phenomena that look very much the same regardless of where it happens (They're refered to as standard candles). A type 1a supernova looks exactly like like a type 1a supernova is expected to look. Except when we look further and further out into the universe, those type 1a supernova and standard candles don't look right. In practice the wavelengths of light they emit look stretched out (redshifted). Some of that could be attributed to motion through spacetime (doppler effect stuff), but not all. Regardless of which direction we look far away stuff always is redshifted, everything at the same distance as it is redshifted by the same amount and as you look further and further away stuff is redshifted more and more. That means either everything else in the universe is moving away us and is moving away much faster the further away it is or it means the universe is expanding. The chances of the first result being true is basically nil, if there was no other factor we'd expect the direction of motion to be basically random, some stuff moving away, some stuff moving closer and everything moving at different velocities in general. So that leaves us with expansion. \n\nIf it was contracting we'd see the opposite, stuff would be blueshifted rather than redshifted. If you want to visualize that, think an ambulance with it's siren on tearing past you. If it's getting closer the noise of it's siren pitches up, getting higher and higher as it gets closer and closer. When it's going away from you the pitch drops and drops lower and lower the further it is. Blueshifting and redshifting behave pretty much exactly the same way, but it changes the frequency of the light rather than the frequence of the soundwaves. \n\n\n2: The geometry of the universe is very probably flat. For a \"big crunch\" to happen, it would require the universe to stop expanding and start to contract. If the universe is flat that process of slowing down will take an infinite amount of time and if the expansion can't slow down to zero it can't ever start to contract. \n\n3: Dark energy is a thing and it's accelerating the expansion of the universe. Exactly what and why that is we don't know, but the effects are clear enough: The more space you have the more dark energy you have. The more dark energy you have the more space can expand. The more space expands the more space you have. That's a positive feedback loop and there's no reason to think it will stop. \n\nSo even if the universe could slow down to zero expansion in a finite amount of time, the acceleration of the universe would also need to reach zero, and there's no reason to think that will happen either. " ] }

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[ "https://www.reddit.com/r/askscience/comments/5dgwjl/does_the_universe_have_an_event_horizon/da5ffdx/?context=3" ]

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{ "a_id": [ "dshkte8" ], "score": [ 13 ], "text": [ "There are basically three elements to this. \n\nFirst. While the the Southern Resource Area was oil rich by Japanese standards it was significantly less productive than other areas of the world at the time. In 1940 while the US produced 183 million tons of crude, the Dutch East Indies produced 8 million tons of crude. The rest of the region added a few million more tons. The US and other Allies also had access to the international market which added places like Venezuela (27Mt), Iran (10Mt), Mexico (7Mt), etc. Japan didn’t have access to any of that. So they were stuck using only the oil produced in the SRA and the tiny amounts produced in pre-war territories (mainly Japan and Taiwan/Formosa). Of the world’s 294 Mt oil output Japan had access to around 11 Mt.\n\nSecond. Japanese occupied territories never matched their pre-war output. One the the very last things the European powers did before the area was captured was to destroy refineries and wells. The Allies also focused on disrupting oil production, much like they did in Europe. So air raids were common. I can’t find mid-war production figures at the moment, but between 1940 and 1945 oil production in the Dutch East Indies dropped from 8 Mt of crude, to less than 1 Mt of crude. At no point did Japan ever get more than a fraction of the production the area had before the war. \n\nThird. Japan had a grossly inadequate fleet of tankers. In December 1942, the country as a whole had 58 tankers, with a total carry capacity of around 600,000 tons. During the war they converted a number of other ships into tankers including passenger ships, they captured foreign tankers, and anything else they could think of. In all around 200 Japanese ships served as tankers. But it was never adequate, especially by mid-to-late-war when the submariners began to focus on the tankers. Japan could never adequately get the little oil they had to where they needed it. By late war the IJN was refueling some ships with raw crude directly from the fields rather than trying to transport the fuel to refineries and then back out to the fleet. This resulted in the damage to a number of boilers, due to the high sulfur content of the Bornean crude.\n\nIn short Japan had access to 3% of the pre-war production, never actually achieved those pre-war figures, and couldn’t have transported if they had.\n\nContrast that to the US, who themselves had local oil shortages at times. The US produced 67% of the world’s crude (and had access to about 80% of the global supply). They managed to increase pre-war production numbers during the war, including opening brand new fields. They had a vastly larger tanker fleet to start the war, and built a ridiculous number during the war. Just counting only the workhorse T2-SE-A1 models, the US built 481 during the war. Which alone accounts for about 2.5x as many as all Japanese tankers that served at all during the war." ] }

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{ "a_id": [ "d15njkv" ], "score": [ 3 ], "text": [ "If you had to organise 200 legs you'd be slow, too.[1]\n\nActually - some centipedes are very speedy, because that's the niche they've evolved to fit, but millipedes aren't predators (that I know of) and have no need for speed.\n\n[1] Actually, they're self-organising - each segment responds in a set way to the movement of the one before, so much of it is automatic." ] }

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{ "a_id": [ "cgy83av" ], "score": [ 3 ], "text": [ "Luck.\n\nThe young man in question was unconscious for most of the trip, luckily for him, but he was certainly dicing with death. Stowing away in a wheel well isn't a surefire way to kill yourself, but this risk is certainly unacceptably high. There's just enough oxygen and heat -- and plenty of pressure -- up there to make survival possible, just not very likely.\n\nIt is usually fatal, though. A few years ago a man literally fell out of the sky onto a street in London. He'd stowed away in a wheel well in Angola and perished on the way; when the plane lowered its undercarriage on its approach to Heathrow, the body fell out and gave several Londoners a nasty shock." ] }

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{ "a_id": [ "d4h12vi" ], "score": [ 6 ], "text": [ "It's a holiday under state law in a handful of states, but it has never been a national holiday. The problem with making it a holiday or having voting on the weekend is that there will still always be people who have to work. If the law mandated that everybody had the day off, then emergency services like police and hospitals would stop and that would be terribly dangerous. Even if first responders and other essential safety personnel worked, it would be a pain for a lot of people for all restaurants, stores, gas stations, etc. to be closed. At the end of the day there's no good way to force a holiday for everyone - our society relies on having access to various services to run and people have to work for those services to operate.\n\nEarly voting exists for people who can't take off on election day. A lot of states also require that employers let employees take a couple hours off from work to go vote." ] }

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{ "a_id": [ "c9yris7" ], "score": [ 3 ], "text": [ "The formula for blood pressure is:\n\n Heart rate • Stroke volume • Systemic vascular resistance\n\n* Heart rate = how many times the heart beats in 1 minute.\n\n* Stroke volume = how much blood is ejected from the heart each time it beats.\n\n* Systemic vascular resistance = the resistance to blood flow caused by the blood flowing through the vessels.\n\nThe systemic vascular resistance is composed of many factors, including the total length of the vascular system, the radius of the vessels, the flow rate of the blood through them, and yes, the viscosity of the blood. Check out the [Hagen–Poiseuille equation](_URL_0_) for more info on that.\n\n**tl;dr - The viscosity of the blood is only one small component of the total contribution to blood pressure.**" ] }

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[ [ "http://en.wikipedia.org/wiki/Hagen%E2%80%93Poiseuille_equation" ] ]

{ "a_id": [ "d58vrag" ], "score": [ 5 ], "text": [ "There is no such thing as a \"typical mentally handicapped person\". Every individual is different and the brain is an extremely complex organ and development or injury affects every individual in different ways. A \"mental handicap\" may manifest completely different in two people depending on nature and/or nurture. " ] }

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{ "a_id": [ "ed4g1o9", "ed4g3yl" ], "score": [ 4, 2 ], "text": [ "It wasn't split during the cold war. It was split 4 ways after the Germans surrendered in WWII, into the Russian, American, English, and French zones. The idea behind splitting Berlin was that the allied powers defeated Germany, and thus each should be responsible for a section of the German capital. ", "Berlin wasnt split during the cold war. Berlin was split immediately after WW2 as the allies divided the city between themselves. The wall, and tensions, came later." ] }

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{ "a_id": [ "c49lt8u" ], "score": [ 2 ], "text": [ "Ok so fat is called a Triglyceride or TAG and it is called that because it is made of three fatty acid chains. This structure is very stable and is unsoluable and is stored in docks called adipose tissue. When the body runs out of glucose and glycogen as fuel it starts burning fatty acids. A number of things need to happen first though.\n\nTo begin with the fatty acids need to be mobilised. This is done through a process called Lipolysis. The three acids are seperated and then transported to the cell that requires the fuel. In this case a muscle cell. Now what the cell needs to do is convert the fatty acid into energy or basically ATP. Through a complicated metabolic pathway they form a molecule called Acteyl Co-A. This molecule enters the energy producing cycle called the citric acid cycle. It is now the same as glucose and goes through the same steps such as the electron transport chain and stuff.\n\nLet me know if you need more detail. Key thing is fat is stored in a stable unsoluable form in adipose tissue. When the body is starving hormones such as insulin activate the degradation of the TAGs into 3 separate chains which then enter the blood and get transported to the starving cell. The cell then uses that fuel.\n\nI think that answers your question." ] }

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{ "a_id": [ "e3vdeen", "e3viflh" ], "score": [ 21, 3 ], "text": [ "Particle masses can be measured in a few ways. Typically, subatomic particle masses are determined by the relationship between their energy and their momentum. If a particle is not moving, its total energy is E=mc\\^2. If it is moving, then E\\^2=(mc\\^2)\\^2+(pc)\\^2, where p is the momentum and c is the speed of light. One way to measure the mass, say, of a proton, is to put it in a mass spectrometer. Accelerating it in a known electric field gives it an amount of kinetic energy proportional to its charge. Causing the proton to move in a circular path in a uniform, well-calibrated magnetic field allows the momentum to be measured quite precisely. \n ", "There is usually some kind of trick being used to measure all of these things. Some properties are very hard to measure and some are very easy so that's were you take advantage of physical laws that makes the easy to measure properties like electric charge and magnetic field depend on the harder to measure property like mass. \n\nThey recently measured the mass of the atom for the 2018 proposed redefinition of SI base units which will define the Avogadro constant as a precise number so they needed the most precise measurements ever done, because will be the number we use for calculating the number of atoms in a mole for possibly hundreds of years. \n\nAnyway, what they did was quite simple. After growing a large 5kg crystal of silicone-28 they cut the crystal into two 1kg spheres. If you make a perfect sphere you can just measure distance (easy) to find the mass of the sphere (hard) by calculating the volume of it. \n\nDiameter measurements on the spheres are repeatable to within 0.3 nm, and the uncertainty in the mass is 3 µg. For a 1kg object an uncertainty of 3 µg is around 10^-9 which is in the range of what we deem acceptable for our fundamental constants, I believe the speed of light had a 10^-10 uncertainty before it got defined as an exact number. The number for Avogadro constant they got was 6.02214078(18)×10^23 carbon-12 atoms in 12 grams of carbon-12. \n\nAll the other possible ways to measure the mass of the atom are explained here: _URL_0_" ] }

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[ [], [ "https://en.wikipedia.org/wiki/Avogadro_constant#Measurement" ] ]

{ "a_id": [ "cfz4slc", "cfz71l7", "cfz9sar" ], "score": [ 4, 2, 2 ], "text": [ "There isn't a sort of flicked switch between free and oppressive. As countries go, Cuba isn't *that bad.* \n\nIt's also poor, yes, but arguably because of US-imposed trade embargoes.\n\nAll the money it spends on medical aid is also a very good PR move - it sends hundreds of doctors to developing countries. It also has free healthcare and a lower child mortality rate than the US, despite spending a fraction of the amount of money per person on healthcare, which is why pro-healthcare reform people like to bring it up as a contrast to the US's current system.", "Probably because the poverty and oppression is a direct result of US actions (economic blockades, etc.)", "Your question is loaded (comes with a clear bias), and so it has been removed. Try rephrasing objectively or else post in /r/changemyview." ] }

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{ "a_id": [ "dedy3dv", "dee41tw", "dee9ami", "dee9gt3", "dee9jj9", "deegcjw", "deeprg5", "deer484" ], "score": [ 1043, 73, 34, 11, 8, 15, 7, 3 ], "text": [ "First, the existence of a magnetic monopole would imply the necessity of electric charge quantization -- the phenomenon that all electric charges are integer multiples of some fundamental charge, a property which is observed but for which we do not have a confirmed explanation.\n\nSecondly, many unified theories imply the existence of monopoles. So if you found a monopole, you could ask, if this is a unified theory monopole, what would it tell you about the unified theory? The mass of the monopole would allow us to determine the energy scale at which unification occurs. Also, in unified theories, the monopoles have a radius determined by the unification scale.\n\nOne last thing: The density of monopoles in the universe is related to the expansion rate of the universe and when that expansion occurred. Inflation -- a period of rapid expansion -- appears to be needed in the context of grand unification, because otherwise there'd be a much higher density of monopoles and we should have seen some already.\n\nBTW, you might be interested to read about Cabrera's experiment that [appeared to detect a magnetic monopole](_URL_0_) in 1982, although since that signal never occurred again, it seems doubtful that one event was real.\n\nEdit: I should add that the connection between the existence of magnetic monopoles and quantization of electric charge was [realized by Dirac](_URL_1_) in 1931. ", "Side question: what could you do with a monopole? Assuming you could make them in large quantities. How would interact with matter, or other monopoles?", "Side questions. Shouldn't there be north monopoles and south monopoles? Would they be antiparticles of each other? Is there an asymmetry that would unbalance monopole production like matter, so there would be one type of primordial monopole left?", "In addition to some of the points made here, it would also necessitate a change in our understanding of Maxwell's Equations. [Here's](_URL_0_) a brief outline of what that would entail.", "Is there any truth to the idea that magnetic fields are always generated by the angular movement of charged particles? Or is that just a metaphor or an old picture that's been entirely replaced by more sophisticated theory? Because if it's a valid model, it would imply that magnetic fields would always have 2 poles, right?", "What would the discovery look like? Supposing a monopole were found, where would it show up, and what would be the evidence for it?\n\nAnother particle at the LHC? An odd signal at a neutrino detector? Something in a solar observatory?\n\n", "Haven't seen this mentioned, but there are examples of [magnetic monopoles in spin ice](_URL_0_), although these aren't strictly monopoles in the way you're talking. \n\nA spin ice is a frustrated magnetic material, due to its pyrochlore structure. Oxygen atoms form tetrahedra around rare earth atoms like Holmium, Dysprosium, etc. \n\nThese tetrahedra have spins that's like to orient either pointing into the tetrahedra or out, the ground state configuration being 2 spins pointing in, 2 spins pointing out.\n\nThere is another configuration that is possible for the spin sites, either 1 pointing in and 3 out, or the other way round. Let one of those be treated as a North and the other a south (I.e. A tetrahedron with 3in1out is a North Pole, and one with 1in3out is a south Pole.\n\nNow since spin ices are crystals, we have a very large periodic repetition of these tetrahedra, all connected to each other. It is clear to see if you flip a spin somewhere, you can go from the ground state 2in2out to either a North or a South Pole, but you necessarily create the other pair of the pole on the tetrahedra touching the edge whose spin you flipped.\n\nSince there are many of these tetrahedra, and you can keep flipping spins, you could, in theory, isolate a North or south Pole, and move it's pair far away from it, by flipping more spins. If there is a 3in1out tetrahedron somewhere in the lattice, there must he a 1in3out tetrahedron somewhere else, but not necessarily near it. \n\nThe theory is then if you move the poles sufficiently far apart, you can perform experiments on the isolated \"monopoles\".\n\nIt is very important to mention almost everyone I've spoken to who works with spin ices, will all refer to them as \"monopoles\" with air quotes, and then quickly mention some disclaimer about how these aren't monopoles in the way most people think, and div (B) = 0 holds. ", "In condensed matter physics, magnetic monopole quasiparticles can exist in spin ice materials when spin flip Excitations fractionalize into a monopole/ antimonopole pair. These quasiparticles are confined to centres of the centres of tetrahedra in the pyrochlore lattice of the material though, so aren't quite the same as free monopoles. However it appears they do follow a coulomb interaction. " ] }

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[ [ "https://en.wikipedia.org/wiki/Magnetic_monopole#Searches_for_magnetic_monopoles", "https://en.wikipedia.org/wiki/Magnetic_monopole#Dirac.27s_quantization" ], [], [], [ "https://www.quora.com/What-form-would-Maxwell-equations-take-if-magnetic-monopoles-are-found-to-exist" ], [], [], [ "http://www.nature.com/nature/journal/v451/n7174/abs/nature06433.html" ], [] ]

{ "a_id": [ "drjmtc5" ], "score": [ 3 ], "text": [ "So I wrote a post on why horse archers were so effective a couple of days ago:\n\n_URL_0_\n\nAs for Roman tactics against them, let's first look at Crassus' campaign. He was a rich man but a horrible commander, and actually was given a good route for his campaign. The King of Armenia offered him safe passage and extra cavalry for his campaign, but Crassus rejected this and instead marched through the desert. One of the most important things to remember when facing an army of horse archers is to avoid terrain that is conducive to their strategies, like the desert, and instead to travel through lands that are bad for cavalry maneuvers, like the Highlands the Armenian king offered passage through. So Crassus chooses the bad option, is led through the desert by Parthian spies without the necessary cavalry support, and ends up getting everyone killed.\n\nOne thing to remember about the Romans is that they adapt, and when they suck at something, they hire someone else to do it for them. During Trajan's campaign 150 years later, he brings along a significant portion of auxiliary cavalry. His units stick to highlands and in his case sail along the Euphrates to avoid fighting horse archers in their natural environment. He uses a tactic much like Richard Lionheart's, where you use a natural barrier to protect your rear, line up infantry in front of significant missle fire, and keep your cavalry in reserve to do measured charges to keep chase off the enemy. Even though he is significantly better prepared, they stop at the Iranian plateau as that would have been a dire defeat for the Romans even with Mauretanian horse auxilliaries.\n\nAs for the Mongols, they did have problems with castles up until their conquest of China and subsequent absorption of Chinese siege engineers. To say they were stopped by sieges in the west is wrong though. They had the capacity to besiege and take castles, but by the time they reach Hungary they are stretched very thin. They do win multiple battles, but have to withdraw because of the election of a new Great Khan. So why didn't they go back and overrun Europe? As I said before, they were stretched thin and horse archer armies work when they can fight on their terms. The Hungarian plain was the end of the steppes. After the Carpathian Mountains, Europe is heavily forested and has swamps and hill country and mountain ranges. It's just not conducive to the Mongol way of war, and unlike China, is not close enough to make the resources needed worth it.\n\nSource: Erik Hildinger \"Warriors of the Steppe\"" ] }

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[ "https://en.wikipedia.org/wiki/Roman%E2%80%93Persian_Wars#Roman%E2%80%93Sasanian_wars", "https://www.reddit.com/r/history/comments/7kt5sb/what_are_some_effective_strategies_against_horse/", "https://en.wikipedia.org/wiki/Mesopotamia_(Roman_province)", "https://youtu.be/bR7VDPUj5AE" ]

[ [ "https://www.reddit.com/r/AskHistorians/comments/7jmpk5/how_did_the_mongols_defeat_armies_with_just/dr8g724" ] ]

{ "a_id": [ "d46juj8" ], "score": [ 6 ], "text": [ "There's always room for discussion, but perhaps this previous topic found through the search function will answer your inquiry.\n\n* [Battlefield 1 Trailer Accuracy](_URL_0_)" ] }

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[ [ "https://www.reddit.com/r/AskHistorians/comments/4i8bj7/battlefield_1_trailer_accuracy/" ] ]

{ "a_id": [ "d6sgusl", "d6shc8j", "d6shd00", "d6shmfz", "d6shpzz", "d6shq4n", "d6sleuw", "d6t1530" ], "score": [ 4, 9, 9, 6, 6, 2, 3, 3 ], "text": [ "I'm assuming that there was no known cure at the time and it was a humane way to prevent a horrible death.", "1. you're gonna die, and pretty soon, and it's incredibly painful.\n2. you are likely to go nutso as the disease progresses and then bite someone, scratch someone or exchange fluids with them someone - you're contagious.\n\nIn days of yore we took slightly more drastic approaches to dealing with this sort of thing....", "If you developed rabies before the vaccine it was a pretty much guaranteed death. And not only would the death be painful, but you would be very confused beforehand and could very easily get angry and hurt someone else, further spreading the disease. It's essentially the same reason people ask others to shoot them in zombie movies if they get bitten.", "There is no known cure for rabies and it is a horrible, horrible death. Being shot is a mercy.", "Before the vaccine was developed, rabies was essentially 100% fatal. Even with modern medicine allowing us to put people in induced comas and load them with fancy drugs, (the [Milwaukee protocol](_URL_0_)) the survival rate is still dismal (out of 36 people treated with the Milwaukee Protocol, only 5 have survived.) \n\nSo back before the vaccine and the Milwaukee protocol, if you were infected, you *were* going to die, and it was going to be **excruciating**. Much better to end it yourself before things got bad.", "Here's a great documentary on rabies that answers your question. It's about the one person who has ever survived symptomatic rabies: _URL_0_ ", "Because you lose self control and might infect others. The death itself is terrible. Imagine drowning yourself slowly.", "Before the vaccine was developed Rabies was virtually 100% fatal.\n\nWorse than that it was a largely slow, painful, and dangerous way to go. You act irrationally and may do things that stand to endanger others.\n\nSimilar to many zombie movies; instead of going through all the torment, people infected \"opted out\" or were \"opted out\" by others." ] }

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[ "https://www.reddit.com/r/tifu/comments/4z25wo/tifu_by_injecting_myself_with_leukemia_cells/d6satum" ]

[ [], [], [], [], [ "https://en.wikipedia.org/wiki/Milwaukee_protocol" ], [ "https://www.youtube.com/watch?v=qdPuXHhEwDk" ], [], [] ]

{ "a_id": [ "d43yerd" ], "score": [ 41 ], "text": [ "I'll only speak for one aspect of the Vandals in that, while certainly proving to be just as if not more destructive than the Huns and Alaric's visigoths--in terms of the sack of Rome they actually proved to be far less Vandal-like. \n\nLike when Attilla and the Huns were at Rome's doorstep, Pope Leo I once again rode out to meet the would-be invaders and attempt to turn them away from the city. However, Leo's position with the Vandals was far weaker. They were far closer to Rome than Attila was, and Leo didn't have the benefit this time of an army at his back. Unlike the Huns though, the Vandals were christian. \n\nWhat this is leading to is that when the Vandals did sack Rome, they made an agreement with Leo. They would take what they want--but they wouldn't harm the citizens. They stuck to their word. The Visigoths certainly didn't do that much. \n\nThough, the Visigoths had a far better reason than the Vandals for wishing to sack Rome in the first place. Alaric wanted to establish a homeland for his people--and attempted multiple times to seek some sort of settlement Honorius. Honorius was too stupid or stubborn to accept Alaric's peace offers.\n\nThings are not very black and white in history. While I can't speak of to how the act of vandalism became overtly associated with the Vandals, I can at least say that their sacking of Rome proved to be far less brutal than the other barbarian invasions of the Western Empire." ] }

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{ "a_id": [ "d1k661h", "d1k8o5f", "d1kcgun", "d1kdhya" ], "score": [ 10, 4, 10, 2 ], "text": [ "The square root symbol is just an object that we made up to keep track of certain quantities. The equation x^(2)-A=0 has two solutions in the real numbers for A > 0. Luckily we know that if x=b is a solution (so b is a number so that b^2=A), then x=-b is *also* a solution. This says two things: 1) We just need to know *one* solution in order to keep track of *both* of them and 2) One of the solutions will be positive. We then *invent* the symbol \"sqrt(A)\" to be the *positive* solution to x^(2)-A=0. This means that the solutions to x^(2)-A=0 are sqrt(A) and -sqrt(a). sqrt(A) is a single value, it can't be both positive and negative.\n\nsqrt(A) symbol invented to represent a single number that can be used as a bookkeeping device in order to keep track of *both* solutions to x^(2)-A=0. We can't have, for instance, sqrt(4)=+-2, because equality is *transitive*. We'd have sqrt(4)=-2 and sqrt(4)=2, which then says -2=2. What we can say is that the solutions to x^(2)-4=0 are x=2 and x=-2. \n\nAn interesting thing is that the equation x^(2)+1=0 has two solutions, but neither of them is positive or negative. In fact, we *can't* tell the two solutions to this equation apart! What we do is then just say that \"i\" is *one* of these solutions. Which one? Doesn't matter. But we can use it to keep track of both solutions, as the other is -i.", " > I am talking about sqrt (36)=+/-6\n\nsqrt(36) = 6 only. sqrt(x) is always positive for x > 0. You are correct the sqrt(x) function can only have one value.\n\n > Can someone give me an example why it is important, I mean why would we be taught that the sqrt (36) is +6 and -6?\n\nI suspect you're misunderstanding the way the sqrt function gets used when solving equations. The equation x^(2) = 36 has two solutions, x = 6 and x = -6. For convenience this gets written x = +/-6, or x = +/- sqrt(36). The sqrt(36) part is still only 6. But x can be sqrt(36) or -sqrt(36).\n\nIt's NOT that sqrt(36) = +/- 6. It's that the equation x^(2) = 36 has the solutions x = +/- 6.", "It's just a convention. \n\n6 and -6 are both square roots of 36, but a convention has been established where sqrt(36) denotes the positive square root. This just reduces ambiguity in mathematical statements. \n\nSaying that sqrt(36)= 6 and sqrt(36)=-6 doesn't really make any sense. How could it be both? Rather, both are square roots of 36, and we denote them by sqrt(36) and -sqrt(36) respectively.", "In physics the negative option often has meaning. For example, when solving a projectile motion problem and determining the final velocity of the object, sometimes the final velocity is positive (up) and sometimes negative (down). Solving the equation gives you two answers and you have to use context to determine which is appropriate. \nEx: What is the velocity of a ball thrown up at 5m/s when it comes back to your hand? \nVf^2 =vi^2 +2ad\nSince the starting and ending position are the same d is 0, so Vf^2 =vi^2 \nAnd Vf=+/-vi.\nYou need to use context to see that in this case the negative value is the only one that makes sense. Vf=-5m/s" ] }

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{ "a_id": [ "cw2wzza", "cw2x15n" ], "score": [ 3, 2 ], "text": [ "I get hunting, and have fired weapons myself (including a 20-gauge when I was a teenager, as well as a South African \"R5\" 5.56mm assault rifle on a range). So I don't \"hate\" guns, nor am I \"scared\" of them, but I still have major issues with the whole concept, philosophically.\n\nStep back a bit and look at the big picture, forgetting specifics for a minute. A gun is a machine for killing people and other animals. It's not the only way of killing, of course, but it makes killing incredibly *easy*. Just point it at someone and squeeze the trigger. \n\nWith great power comes great responsibility, then, and I frankly don't want that kind of responsibility. Some bad guys have guns, so I should have guns too? That's a circular argument, and it's how arms races start. The bad guys know I have guns, so they get more and/or bigger guns, so should I follow suit? If someone breaks in on me in the suburbs at 4AM, and I started firing my little Glock (or whatever), I doubt that the intruders would be in any danger. \n\nWhere does it end? What kind of society would it be if guns were both the problem and the solution? I don't have kids, but if I did, would they be able to go outside and play, away from parental gaze, have fun, and come back safely? My idea of a world safe for everyone is not one that requires guns at all. ", "Very few people believe in the extreme statement that \"no one should own guns.\" Most reasonable gun control advocates just want to make it harder to acquire new guns. They argue for things like background checks before purchase, mandatory 3-7 day waiting periods between purchase and receipt of guns. \n\nIdeally, these measures would slow down the flow of illegal firearms into unsavory hands, both here in the US and abroad, while still allowing law abiding individuals like you or me to purchase firearms for our own defense.\n\nFor what it's worth, I've never met a single person that actually supported taking firearms away from their legal owners. " ] }

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{ "a_id": [ "c9k3da2", "c9lj97v" ], "score": [ 2, 2 ], "text": [ " > I was wondering if two people standing next to one another see distinct photons\n\nAny time you and another person see the same thing, you are actually seeing distinct photons. When you see something, it means photons from that object have been absorbed by your retina; the same photon can't be absorbed by the retinas of two different people.\n\n > how does something so far away \"cover\" the entire side of the Earth (facing the source) with photons? \n\nIt does by emitting a *huge* number of photons. In some sense, that's the definition of something which is visible.\n\n > I realize the light is red-shifted and the wave is stretched out as it travels away from the source\n\nThe light from stars we see is not necessarily red shifted. While on a large scale, the universe is expanding, that's not reflected in the motion of nearby objects. For things in the galaxy, the light can be red-shifted or blue-shifted depending on the local velocities of the stars relative to us.\n", "As /u/fishify said, \"seeing\" something means your eye absorbed the photon, so you and your friend must be seeing distinct photons. How many of them will each of you see given your Sun-like star 1000 ly away? Here's a back of the envelope calculation. \n\nThe luminosity of the sun is 3.85x10^33 erg/s. The flux through an area is just given by an inverse square distance law (i.e., the area of a shell into which the flux passes gets larger as d^2). \n\nSo F = L/(4 pi d^2). But what is the photon flux? We have to know the energy of each photon. It should be handled with an integral and the star's true spectral energy distribution, but let's just say the average photon has a wavelength of 500 nm ~ 6e14 Hz. The photon's energy is h nu = 4e-12 erg. F/(h nu) gives the number of photons per area per second. Plugging in the relevant numbers, we find the flux from a Sun-like star 1000 ly away is ~100 photons/cm^2 every second.\n\nThe atmosphere will reflect and absorb ~half of those before they ever reach the surface, but the human eye is a couple square centimeters, so let's call it even. Your eye will receive **~100 photons every second** from this distant star.\n\nNote that the biggest assumption I made was that all photons have wavelength ~500 nm. Luckily, the Sun puts out most of its energy in the visible, so it's probably not a terrible assumption. And this is astronomy, where pi is 3 and 3 can be 5 or 2 depending on the situation, so good enough.\n\n" ] }

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{ "a_id": [ "epvglnu", "epvjmo2", "epvmseq", "epvstju", "epvwfux", "epvx2x2", "epvy1m1" ], "score": [ 7, 13, 17, 49, 3, 4, 22 ], "text": [ "It used to be common for women to have babies at 13 or so. We have since gained a better understanding of the emotional development of children and realize they are nowhere near fully developed at 12 or 13.", "I’d say that modern medicine and how we have better nutrition nowadays has also affected this. Thoughts?", "Evolution and natural selection. There may have been subsets of women that didn’t hit menarche until they were 16/18/20 but back when you only lived to 25 or 30 that would have been a serious disadvantage. Women with the genes to hit it earlier would have been selected over time because they would have had more children and earlier. Fast forward to today, and most women can have kids earlier. There will always be mutations that cause some women to hit menarche later, and now that modern medicine exists they have a much much better chance of having healthy fertile offspring that survive and stuff, but since we come from the branch of the tree where women had kids early, most women will be able to have them early.", "I see a lot of people mentioning evolution. Valid to some point. But a huge influence are \nendocrine disruptors like BPA. A few decades ago it wasn't common for girls as young as 9 to get their period. The chances of surviving a birth as a 9 year old are also pretty low.", "The trend of the average age of menarche going down almost every year since at least the early 19th century has multiple factors mostly devided into genetical and environmental factors.\n\nFrom an evolutionary stand point it seems to be advantageous to reach menarche and later fertility at an early age especially in respect to pre-modern societies and still today it seems to increase the possibility to produce offspring.\n\nYet we can see that the average age of menarche going down possibly leads to girls becomming fertile at an age ([US: \\~11 in the 1990's](_URL_1_)) that seems to be to you young to produce and sustain healthy offspring.\n\nLooking at environmental factors we can see a correlation (2+ things happening at the same time) between the age of menarche going down and an increase in living standards. Because we know that a higher amount of fat in the body mass of girls triggers puberty/menarche we can conclude that to some extent the availability of food became a majore factor in driving the average age of menarche down.\n\nWithin the last 200-300 years things like the introduction of corn, potatoes and bird poo fertilizer world wide that lead to the industrial revolution, the development of synthetic fertilizer by Fritz Haber, the development of new strains of plants like wheat that can grow in regions where they formlery could not, etc. all possibly lead to this.\n\nLooking at more recent developments like the development and introductions of chemicals into our lives might have also impacted the average age of menarche. For example some chemicals might change hormone (chemicals that control your body) levels in our body like BPA and could also lead to an earlier puberty/menarche.\n\nDr. Sandra Steingraber mentions the following in her paper she did for the brestcancerfund:\n\n > \\- low birth weight & premature birth \n > \n > \\- obesity and weight gain \n > \n > \\- formula feeding (feeding infants milk powder) \n > \n > \\- physical inactivity \n > \n > \\- psychosocial stressors \n > \n > \\- television and media consumption \n > \n > \\- environmental exposures\n\nThese correlations do not mean that this is the definitive reason why the average age of menarche went down but it is likely that those factors contributed to it.\n\n & #x200B;\n\nEdit:\n\nMore detailed:\n\n > [During the last 50 years, however, additionalforces seem to have been at work. The evidence suggests that children’s hormonal systems are being altered by various stimuli and that early puberty is the coincidental, non-adaptive outcome. The intricate and innately reactive HPG and HPA axes are highly vulnerable to disruption, and this disruption can take many shapes. Obesity is one manifestation of endocrine disruption and may lead to hyperinsulinism,leptin resistance and enhanced aromatase activity. Preterm birth and intrauterine growth restriction—especially when followed by rapidweight gain—is a second kind of endocrinedisruptor that raises the risk for early pubarche.](_URL_0_)", "We're the only mammals that go through puberty. Reasonable to assume that there is a genetic advantage to it.\n\nModern medicine aside, women about 25 years old are more likely to have a healthy baby than other age groups. That's almost 10 years of her looking fertile but being not yet fully fertile.\n\nOne theory is that she is in practice mode. She looks like a woman and starts to take on more household duties, including childcare. Courtship can take years and the guy is more likely to be interested if she looks like a woman rather than a child. By the time she is fully fertile, she will have spent many thousands of hours doing what mothers do.", "Not being emotionally ready isn't purely down to age, that's a society thing too. In the UK for example (or in my experience at least), kids are allowed to just be kids and generally are up until at least 13-14. In some cultures though, by this point they may have been teaching/grooming them into adulthood and talking about having their own kids for years.\n\nDoesn't explain the physical side though, I really don't know about that." ] }

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[ [], [], [], [], [ "https://web.archive.org/web/20101227114059/http://www.breastcancerfund.org/assets/pdfs/publications/falling-age-of-puberty.pdf", "https://en.wikipedia.org/wiki/File:Acceleration1.jpg" ], [], [] ]

{ "a_id": [ "dhhq2df" ], "score": [ 10 ], "text": [ "Oo! A question that I can help answer in part!\n\nFor what it’s worth, I’m not a historian, but I do have a degree in history. I’m currently a law student in Australia, which has a similar Solicitor/Barrister split profession. I can’t speak to how the American profession developed, but I can talk about how the English/Welsh (and by extension, Australian) profession developed separately.\n\nFirst off, currently in England and Wales, solicitors are actually entitled to appear before many Lower Courts, and it’s really only in the superior courts that barristers become truly necessary. However, the profession is still very split in certain jurisdictions in Australia.\n\nThe development of the split profession is largely something of a historical accident.^1 The distant ancestor to the modern barrister, the ‘Serjeants-at-law’, were an import of the Norman Conquest of the 11^th Century. As an aside, this is also why so many older English precedent is peppered with French. From at least 1216, English courts were beginning to limit the rights of audience to ’regular’ advocates’.\n\n**The Initial Split**\n\nUnder King Edward I, the two separate branches were beginning to emerge. A pleading system was established, whereby specially trained serjeants would conduct legal arguments, while an Ordinance of the King placed legal representatives under judicial control, ending the clergy as lawyers in the Court.^2\n\n**Solicitors**\n\nOriginally, Courts would require litigants to show up, plead their case, and receive judgement.^3 However, over time, courts relaxed these rules, and allowed litigants to appoint agents to appear and speak on their behalf. Obviously, lawyers did not appear out of nowhere as a profession, and these agents were not initially professionals.^4 The right to an ‘attorney’ was declared by Parliament in the 15^th Century. \n\nAs the number of cases and the amount of litigation increased in the 16^th Century, the number of terrible, unscrupulous and immoral solicitors increased at the same time. Therefore, in 1605, Parliament enacted the first of what we now would consider to be the solicitor’s standards and practices, requiring written statements for fees, and requiring written accounting for disbursements made on the client’s behalf.^5\n\n**Barristers**\n\nIn England and Wales, barristers operate out of Inns of Court: The Honourable Society of Lincoln’s Inn, the Honourable Society of Gray’s Inn, the Honourable Society of the Middle Temple, and the Honourable Society of the Inner Temple. These trace their origins to the late 13^th Century, where legal professionals would live, learn, work and socialise together. These societies were the ancestors to the ‘Bar’.\n\nBeneath the serjeants were the ‘apprentices-at-law’ and ‘utter barristers’,^6 who were recognised in 1532 as men ‘learned in the law’, and in 1590 required a ‘call to the bar of an Inn of Court’ as the minimum qualification for rights of audience before a higher common-law court. In 1596, the QC or KC (also known as a ‘silk’) rank of barrister was established, and by the 19th Century, no more serjeants were appointed. Barristers and ‘silks’ now comprised the entirety of the Bar.\n\n**The Formalised Split**\n\nHowever, from the 16^th Century onwards, the Privy Council, the Judiciary, and the Inns of Court themselves began excluding attorneys and solicitors from membership of the higher prestige inns.^7 Because of the way the judiciary works, only those who are ‘called to the bar’ are entitled to appear before the Court to argue cases. By excluding solicitors from membership of the Inns of Court, it essentially made it impossible for them to be called to the Bar, and so restricted the right of appearance to those barristers who were members of the Inns of Court.\n\n**Conclusion**\n\nIt’s really this exclusion of solicitors and attorneys (who have since been combined) that solidified the split profession. Although we can see that the profession had been split to some extent from 1216 onwards, it wasn't made explicitly formalised until the Inns began excluding solicitors, preventing them from being called to the Bar, and removing their rights to appear before a higher Common-Law Court.\n\n**Sources**\n\nA note on sources: These are written from the perspective of American jurists and scholars. As such, there may be implicit bias in regards to the split profession. I was unable to find a British source when I ran an academic search, but I'm sure they are out there.\n\n1. Judith L. Maute, \"Alice's Adventures in Wonderland: Preliminary Reflections on the History of the Split English Legal Profession and the Fusion Debate (1000-1900 A.D.)\" [2003] 71, 4 *Fordham Law Review* 1357, 1358 ('Alice's Adventures in Wonderland').\n\n2. Ibid 1360, citing Robert Megarry, Inns Ancient and Modern 10 (Selden Soc'y 1972). See also Harry Cohen, \"The Divided Legal Profession in England and Wales - Can Barristers and Solicitors Ever Be Fused?\" (1987) 12 *The Journal of the Legal Profession* 7, 12 ('The Divided Legal Profession').\n\n3. Ibid.\n\n4. Alice's Adventures in Wonderland, above n 1, at 1360, citing Edmund B.V. Christian, A Short History of Solicitors 3, 9 (1896) \n\n5. Ibid, 1361.\n\n6. Ibid, 1366 citing Robert Megarry, Inns Ancient and Modern 10 (Selden Soc'y 1972).\n\n7. Ibid. See also \"The Divided Legal Profession\" at 12, citing H. Kirk, Portrait of a Profession 18 (1976)." ] }

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{ "a_id": [ "c8xjj2i", "c8xll8y" ], "score": [ 8, 25 ], "text": [ "If this is a question you're interested in, you should read up on [Brithenig](_URL_0_), a constructed language based on the idea that a latin romance language eventually displaced the local languages of Britain. Some of the various discussion boards related to the language have debated your question long and hard.", "We can't know for sure, but it was probably somewhat similar to English in India: it was a language of administration and law, a literary language, and a common language, particularly in the towns. Unfortunately we just don't have enough writing from Britain to know for certain." ] }

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[ [ "http://en.wikipedia.org/wiki/Brithenig" ], [] ]

{ "a_id": [ "c4wvjzp", "c4wwi4p", "c4wwoya", "c4wx7ei", "c4wy0k4", "c4wygg7", "c4wyx50", "c4wztuk", "c4x49s3", "c4xaoby" ], "score": [ 2, 2, 3, 3, 2, 2, 2, 2, 2, 2 ], "text": [ "David McCullough's *Truman* is very good.", "Public Opinion by Walter Lippmann may be right up you alley.", "I can only give limited advice about *The Rise and Fall of Communism* as I just skimmed through a few pages of the book in a local Barnes and Noble but it seems to be a well-written book; however, I would also suggest you look at another book about communism that came out not too long ago called *The Red Flag: A History of Communism*, which seems to be a much more entertaining yet still enlightening book (this observation, too, is made from reading just a few pages at B & N). *Nixonland* is a good read but nothing incredibly memorable.\n\nHere's a small list of selections from a variety of topic areas so hopefully one of these will suit your interests:\n\nEdmund Morris's biographies of Teddy Roosevelt are excellent. If you want to continue with TR, check out Douglas Brinkley's *The Wilderness Warrior*, which details TR's campaign for environmentalism. Brinkley is by far the best writer of history I have come across in a long time, so if that book doesn't interest you I urge to look at his other books. No matter what the subject, his books are incredibly engaging.\n\n*Private Empire* by Steve Coll: This book is written by the Pulitzer Prize winning author of *Ghost Wars* and gives a detailed, objective history of ExxonMobil. Very well written and very informative about the strength of ExxonMobil's lobbying power both within the US and throughout the world.\n\n*One Minute to Midnight* by Michael Dobbs. Covers Cuban Missile Crisis and the book's argument is that no one really had control over what was going on. The world could have slipped into nuclear war even though no one wanted that simply because many factors were at play that could not be accounted for or stopped. Great read.\n\n*Guests of the Ayatollah* by Mark Bowden. He's the author of *Black Hawk Down* and writed in a very readable, journalistic style similar to Steve Coll. This book is about the Iranian Hostage Crisis of 1979 an goes through the 444-day ordeal through the vantage points of the hostages, hostage-takers, and major political figures. Well-researched and maybe the most entertaining read on this list.", "In the Talons of the Eagle", "Why Nations Go to War by Stoessinger.\nThis book gives a broad history of international relations, starting in WWI and going through the Iraq war. Its a good intro, as it provides a broad base of international political theory, and if you find a particular event you are interested, you could find something more specific", "Obligatory question: What languages do you read/speak?\n\nIf German is among them, get anything you can from Jochen Bleicken on the Roman Republic. *The* authoritative work on its law and structure.", "A Political History? If you're of a philosophical bent and interested in the history of ideas consider reading *The Origins of Political Order* by Francis Fukuyama. I suspect this book is going to be fairly influential in academic circles for a long time so wether you agree with it or not you should read it.", "With Latin America, I may be beating a dead horse on this one but I would suggest reading Motorcycle Diaries by Che Guevara. It provides a great deal of context about the political and economic issues about Latin America through the eyes of Che himself before he became the controversial revolutionary figure that continue to provide divided opinion.", "I would suggest [Diplomacy](_URL_0_), by Henry Kissinger. Say what you will about the man's politics, but the man knows the art of diplomacy.", "*Eugene V. Debs: Citizen and Socialist* by Nick Salvatore is pretty interesting and a bit off the beaten path. Debs was one of the most well known socialist's of the early 20th century (ran for president 5 times) and was heavily involved with the IWW." ] }

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[ [], [], [], [], [], [], [], [], [ "http://www.amazon.com/Diplomacy-Touchstone-book-Henry-Kissinger/dp/0671510991" ], [] ]

{ "a_id": [ "ekh4l9m", "ekh4xa8", "ekj9df6" ], "score": [ 2, 4, 2 ], "text": [ "I think you’re looking at it the wrong way. The caveat of chromosomal abnormalities or disorders is that more often then not they affect more than just intellectual ability or mental states, they often affect the CNS and CV system and issues with those bodily functions causes the shorter life expectancy.", "Defects typically worsen things and do not improve them.\n\nSome defects have more negative effects than others. That is a matter of statistics.\n\nIn very rare cases, anomalies turn out to be no \"defects\" but improvements, but the statistical probability for this is very low.\n\nSo bottom line: If you introduce a random change in the genetic code of something as complex as a human, the likelihood of worsening sth. is much greater than the likelihood of improving something.\n\nThink of it as computer code: If you change a random line of code randomly (mutation), most likely the program's performance will degrade and will crash earlier than without this change.", "A human normally has two pairs of every chromosome. Half of these are inherited from the mother and half of them from the father, and as a result each one can have slightly different versions of each gene. When one of your cells need to make a protein, it takes a copy of every version you have for that gene and uses them to make proteins. This is normally a good thing, because it protects you from negative mutations - even if one of your copies gets damaged and doesn't make functional proteins, you still have a spare copy that works correctly. But as a side effect of that system, the rate of protein production is based on the number of genes in your genome that code for that protein. \n\nNormally, that doesn't matter because you have exactly two pairs of everything. But if you are missing a chromosome, you will have only one copy of every gene on that chromosome and you will only make half as many of whatever proteins those genes code for. If you have an extra chromosome, you'll have three copies of those genes and make 50% extra of every protein. If you're missing part of chromosome, you'll half 50% less of whatever that the missing part of the chromosome codes for. If you had four of a chromosome, you'd get double the proteins coded for. And so on and so forth.\n\nTo understand why this is bad, imagine that you're using a recipe to bake a batch of cookies. If somebody takes your recipe and edits it to include 50% extra baking soda, you'll probably still end up with cookies, but they won't turn out as well and might fall apart or taste wrong. If that person edited the recipe to cut the cooking time in half, the cookies will be soft and floppy and might give you food poisoning. And that's just one change - imagine if they made multiple changes like that, all throughout the recipe. In this analogy, genes are steps listed in the recipe, proteins are the steps that you follow and the cells in your body are the cookies." ] }

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{ "a_id": [ "c31ckad", "c31d35x", "c31igtu", "c31ckad", "c31d35x", "c31igtu" ], "score": [ 3, 11, 3, 3, 11, 3 ], "text": [ "Both, depending on your reference frame and the magnitude of the acceleration.\n\nHowever, if the car is travelling at a constant velocity, the fly remains in the same place with respect to the car.", "A fly's motion is based on the objects it is in contact with, as well as the gravitational pull of the Earth. A fly would be hovering because the force exerted upwards by the air on the fly's wings is balanced out by the gravitational pull of the earth. Now, if the car were to accelerate, it would bring all of the air with it. Some of the air would be compressed towards the back of the car, which would cause the fly to go backwards a bit, but regardless, the fly should be able to hover there.\n\nYou can test this with a helium-filled balloon. Be aware of the tension force from the string (you cannot tie it down).", "The fly will hit the rear window. Recently, the International Space Station had to do what is called a re-boost to compensate for the slight amount of drag that the atomic oxygen in the near vacuum of space exerts on the station itself. The conditions are very similar to brutalfox's question. Watch for yourself what happens.\n\n_URL_1_\n\nWhy they do a re-boost:\n\n_URL_0_\n", "Both, depending on your reference frame and the magnitude of the acceleration.\n\nHowever, if the car is travelling at a constant velocity, the fly remains in the same place with respect to the car.", "A fly's motion is based on the objects it is in contact with, as well as the gravitational pull of the Earth. A fly would be hovering because the force exerted upwards by the air on the fly's wings is balanced out by the gravitational pull of the earth. Now, if the car were to accelerate, it would bring all of the air with it. Some of the air would be compressed towards the back of the car, which would cause the fly to go backwards a bit, but regardless, the fly should be able to hover there.\n\nYou can test this with a helium-filled balloon. Be aware of the tension force from the string (you cannot tie it down).", "The fly will hit the rear window. Recently, the International Space Station had to do what is called a re-boost to compensate for the slight amount of drag that the atomic oxygen in the near vacuum of space exerts on the station itself. The conditions are very similar to brutalfox's question. Watch for yourself what happens.\n\n_URL_1_\n\nWhy they do a re-boost:\n\n_URL_0_\n" ] }

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[ [], [], [ "http://www.youtube.com/watch?v=8MR3daaWLXI", "http://www.youtube.com/watch?v=cmHamp0IIyE" ], [], [], [ "http://www.youtube.com/watch?v=8MR3daaWLXI", "http://www.youtube.com/watch?v=cmHamp0IIyE" ] ]

{ "a_id": [ "dx263s6" ], "score": [ 14 ], "text": [ "No. Heat may continue to diffuse through the object, which may cause it to appear to be increasing in heat for a short while (e.g. if you're measuring temperature at a different spot from where it's being heated) but the max temperature wouldn't rise without a heat source." ] }

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{ "a_id": [ "dg2atfg", "dg2js3u" ], "score": [ 8, 2 ], "text": [ "I think it might have to do with our hunter gatherer ancestors. We have a need for knowledge of everything near us, so we can be aware of predators, food, and other things either beneficial or detrimental to our survival. ", "1. I think the proper answer is: \"Does it?\" Does it really for everyone or even a majority? I doubt it does, we're just seeing the especially blatant offenders on youtube falling on their noses...\n\n2. Furthermore, there's another effect at place: Things you are curious about are very specific things just in front of you, stuff to see, touch, something to go to, something to actually *do*. While all the reasons why it might not be a good idea are, at least at that very moment, abstract concepts of what *might* happen. People usually refer better to things they can vividly imagine than some abstract ideas they might have about a possible future.\n\n3. I think that people often massively misjduge how dangerous something can be due to lack of knowledge. Assume I show you a shining, nice, perfecly glittering disk in front of you. Why not touch it? It is interesting, it is not loud, what could be the issue? You have no way of telling it is actually a mass of 500 kg of pure tungsten with razorsharp blades that spins with 5000 rounds per minute and will take anything right off that comes close.\n\nDue to 2. and 3., many people often think they are more in control than they are, that something is more safe that it actually is. Just watch any rallye video on youtube and I bet you'll find some moron standing way too close to 1000+ kg cars barrelling past beyond any speed that could be considered safe... but I bet any of them will tell you \"It is safe, I know cars!\" [Fallacy: You knowing how to fix breaks is not preventing that car from flipping over in just the wrong moment] or \"It is safe, I have done this before\" [Fallacy: Just because you were lucky in the past has no bearing on this situation] or \"It is safe, I just make photos\" [Fallacy: Whatever the people think is a reason... actually isn't causally related at all].\n\nOf the countless people who refrain from most \"stupid ideas\" because \"it is not worth it\" you never, ever hear. \n\n\n" ] }

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{ "a_id": [ "d34f48b" ], "score": [ 2 ], "text": [ "They use a technique called \"ion-mobility spectrometry\". What happens is they ionize the specimen swabs and then travel through a tube with an electric field and a buffer gas that opposes the motion. The speed at which it will pass through the tube indicates what the material is made of, and it is calibrated to trigger on explosives residue.\n\nHopefully if someone has a bomb they would have to handle it, and the very faint residue of that handling would be detected by the device." ] }

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{ "a_id": [ "c41mj1c", "c41ml9z" ], "score": [ 3, 2 ], "text": [ "Entropy increases over time. It's a fundamental law of thermodynamics.\n\nHowever, the universe in it's current state isn't infinite, it had a start at the Big Bang. At the Big Bang, the universe had an incredibly low entropy. Why this is isn't entirely known, and there's a lot of speculation on the topic. We currently exist in a time frame where the low entropy is playing out. In a VERY long time (Like 10^10^36 years) the universe will reach it's maximum state of entropy, and no trace will be left of what transpired over the lifetime of the universe. \n\nPresumably this will carry on for an infinite amount of time, assuming time has any meaning in a maximum entropy environment.", "The accepted age for the universe is just over 13 billion years. So the universe hasn't had time to reach maximum entropy.\n\nBut if you want to consider where this universe came from...\n\n1. The universe just appeared from nothing. Don't know how that could happen, why it happened. Certainly doesn't answer or explain anything.\n\n2. The universe was created by a process that creates universes. But this implies that the process exists in an environment that is not at maximum entropy - so the process can't have been around eternally and must have had a beginning - infinite regression. Still not a useful answer.\n\n3. Our understanding of entropy is wrong and there are circumstances where systems don't tend to maximum entropy. (systems at maximum entropy can cycle through a series of states and maybe a partial view of part of this sequence could be mistaken for an increasing entropy system). Still - big hole in our knowledge here. (Entropy can be temporarily reversed in part of a system (pumping water up-hill) but only at the expense of increased entropy for the system as a whole).\n\n4. Something else." ] }

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{ "a_id": [ "e1hsldd", "e1hswwk", "e1htnki" ], "score": [ 6, 2, 3 ], "text": [ "It depends who it's for. Alot of the time it's a show of dominant behavior or even submissive depending on the person. This can lead to people being uncomfortable. \n\n\nOther times for fewer people it's the start of a soul gaze, which is something most tend to avoid.", "Cuz you consider it an intimate activity and don't feel doing it to strangers. Would you like holding hands with strangers?", "We are animals. There are certain animals that instinctively respond to a stare as a THREAT. \"This PREDATOR is LOOKING AT ME\" sort of thing. Humans have, for the most part, a modicum of ability to override instinctive behavior and do JUST THE OPPOSITE. I like looking into my lover's eyes and being extremely intimate at certain points in time. Both partners usually do. It can be an intense connection.\n\nThat being said, a PET will also STARE at you when they WANT SOMETHING. I guess that could be considered part of a predatorial response. " ] }

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{ "a_id": [ "e7nihs2", "e7nj59q" ], "score": [ 2, 5 ], "text": [ "I can’t explain, but I fully agree, about the yard signs especially. \nThe ones they put along roads and such (not the ones that ppl put on their own private property). \nPost election, if the signs are still up. For say > 30 days, they should get a fine per sign. ", "You can't stop people from mailing you stuff or leaving it at your house but most towns have regulations around those signs that they leave on people's lawns. My town has these regulations:\n\n\\- Need to get an owner's consent to put a sign on their lawn.\n\n\\- Person needs to track where they put them. Candidates are responsible for them all.\n\n\\- After an election the Candidate is responsible for removing all the signs they put around town, within a certain amount of time\n\nOtherwise they are subject to fines. Check your local regs. Maybe they exist but no one's enforcing them." ] }

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{ "a_id": [ "cqr66n5" ], "score": [ 9 ], "text": [ "For objects in a circular orbit, the force of gravity is always perpendicular to the direction of motion. That means that gravity does not pull the object to go faster in its current direction, but instead only changes the direction without affecting the speed of the object." ] }

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{ "a_id": [ "ddnsm0s" ], "score": [ 12 ], "text": [ " > It seems to imply that to a distant observer, the field due to a charge at the event horizon of a black hole would have to be spherically symmetric around the center of the black hole (at least, assuming a spherical black hole). \n\nOk, when people say a black hole is only described by its mass, charge and angular momentum, there's an important caveat that this only applies if you wait a bit for things to stabilize. For example, consider this [animation of two merging black holes](_URL_0_). Immediately after they merge, the merged black hole is still wobbling and the gravitational field produced by this is dynamic, so it goes beyond just mass, charge and angular momentum. But the wobbling black hole is emitting gravitational waves, and in doing so stabilizes into a static state after some time.\n\nSame thing if you dump electric charge into the black hole. From your point of view, you observe the charge being scrambled at the event horizon and the associated dynamic EM field. Over time, the charge will get evenly distributed over the event horizon and radiate away EM waves until everything stabilizes and you get a static electric field.\n\nThe important thing is that everything happens at the level of the event horizon from your point of view. You never get any information of what's going inside. For example, the wobbling black hole can be seen as an elastic beach ball without concern for what's inside the ball. Similarly, when you dump charge in the hole, you see the charge flowing through the beach ball's surface.\n\nBut if you wait long enough, the black hole will look like a nice sphere described only by mass, charge and angular momentum, after it has finished scrambling what you tossed inside." ] }

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[ [ "https://www.youtube.com/watch?v=I_88S8DWbcU" ] ]

{ "a_id": [ "c8fby31" ], "score": [ 2 ], "text": [ "Assuming no strong cold or warm air advection is taking place, it's normally the coldest just before sunrise. You can clearly see the diurnal temperature trends in [this hourly weather graph for Phoenix, Arizona](_URL_0_).\n\n" ] }

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[ [ "http://i.imgur.com/IuqdQjl.png" ] ]

{ "a_id": [ "c6ifvdq" ], "score": [ 3 ], "text": [ "I suppose you're here talking about computers and not the dance.\n\n**ELI5 answer :** Java is a programming language which allows to create programs.\n\n\n**Long answer :** Unlike other programming languages like C++, the code is interpreted by another program (called the JVM, Java Virtual Machine) which renders the result. Most programming languages doesn't work like this ; they compile code into binary data which can be directly used by the computer. Java is also a *object-oriented* programming language, but defining the *object-oriented* notion would require another ELI5." ] }

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{ "a_id": [ "cjj28ua", "cjj4fs5" ], "score": [ 4, 2 ], "text": [ "Interesting, I always thought about it from the other point of view. If you consider a man to be the best human and a role model to pattern your life on, wouldn't it follow that it should be a very common name? Muslims are supposed to love the prophet Muhammad more than their parents and we know that naming children after people you love is pretty common. With that logic, I think the question should be, why aren't Jesus and Moses more common names?*\n\n*Among Christians and Jews, respectively, of course. They're both relatively common names in the Muslim world (with the Arabic pronunciation, of course).", "\"Jesús\" is very common in Spanish-speaking countries; the English variant \"Joshuah\" is reasonably well known. Here are a few related threads on the popularity of the names \"Muhammad\" and/or \"Jesus\":\n\n* [Why do Muslims consider it alright to name their children after Mohammad, but Christians in most western countries don't name their children after Jesus?](_URL_1_)\n\n* [Why is 'Jesus' not a common name for English language people, but very common for Spanish?](_URL_3_)\n\n* [Was Jesus ever a popular name for boys among English-speaking countries (like how Jesús is for Spanish speaking countries)? If so, when did it stop being common and why?](_URL_4_)\n\n* [Has \"Jesus\" ever been a popular name in the Western world outside of Spanish speaking countries? Why is Jesús popular in Spain but not popular in other Christian influenced cultures?](_URL_0_)\n\n* [Is there a historic reason why Latin American Christians are willing to name their children Jesus, whereas European Christians are not?](_URL_2_)" ] }

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[ [], [ "http://www.reddit.com/r/AskHistorians/comments/1sl9ta/has_jesus_ever_been_a_popular_name_in_the_western/", "http://www.reddit.com/r/AskHistorians/comments/ytmu2/why_do_muslims_consider_it_alright_to_name_their/", "http://www.reddit.com/r/AskHistorians/comments/1c5s4i/is_there_a_historic_reason_why_latin_american/", "http://www.reddit.com/r/AskHistorians/comments/1zqscq/why_is_jesus_not_a_common_name_for_english/", "http://www.reddit.com/r/AskHistorians/comments/21z27w/was_jesus_ever_a_popular_name_for_boys_among/" ] ]

{ "a_id": [ "ceefio9" ], "score": [ 5 ], "text": [ "Here's a taste of how accurate orbital calculations are: in 1676 Romer proposed that there was a finite speed of light when he noticed that Io, a moon of Jupiter, was some times 8 minutes ahead of \"schedule\" (predicted location) and sometimes 8 minutes behind. 8 minutes. 350 years ago. " ] }

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{ "a_id": [ "dtzebr3", "dtzlfuv" ], "score": [ 3, 2 ], "text": [ "Plants only produce pollen from their flowers (or cones, etc.). So if your friend would like some plants inside her house she just needs to make sure they don't flower (i.e. cut the flower buds off). Some plants flower more often or easily than others. Cacti rarely flower, in my experience.\n\nFerns produce no flowers but they reproduce using spores. As long as your friend is not also allergic to fern spores, that could be an option.", "No, only a subset of plants [disperse pollen by air](_URL_0_). Other plants that are pollinated by insects have pollen that's too heavy and sticky to get carried in the air.\n\nI'm pretty sure it's impossible to have an allergic reaction to *all* plants. Has she gotten a proper allergy test? Usually pollen allergies are caused by a few specific plants that are grown in your area and release lots of pollen.\n" ] }

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[ [], [ "https://en.wikipedia.org/wiki/Anemophily" ] ]

{ "a_id": [ "fm8qnl6", "fm90337", "fm931f3" ], "score": [ 234, 102, 11 ], "text": [ "These sites do one of two things.\n\nThey operate in a jurisdiction where it would be difficult to shut them down.\n\nIf they are ever actually shut down, they simply create a new site and port everything over.\n\nIt's usually a game of whack-a-mole. With law enforcement trying to shut them down but the sites simply coming back up with a new domain name.", "Many of these sites operate out of jurisdictions where it's difficult to shut down the site. They aren't hosted in US datacenters for example.\n\nThey also obfuscate their ownership. Shutting down a site and holding the people involved responsible are two different things. The copyright holders prefer the later to send a message.\n\nThey are also prolific and easy to spinup/move. If a particular site gets shutdown, 3 will pop up to take it's place within hours, and the authorities are well aware of this fact.\n\nTaking down a major player like the PirateBay seemed like a big win for the authorities but the site was back online within hours under new ownership and in a new location. Then the process of taking them down had to start all over again.\n\nLegal proceedings are expensive and take time, so the copyright holders can't afford to take every single one of these sites to court. Part of the problem is that it isn't profitable to do so, many of these sites have no real assets and are run as a hobby, so you ~~can~~ can't squeeze a multi-million dollar settlement out of them to cover your costs.\n\nSome of the big media companies are finally waking up to the idea that a lot of people don't pirate because it's free, they did it out of convenience. A lot of early piracy was driven by peoples realization that you could download a show and not have to tune in \"same Bat time same Bat channel\" anymore, or have to wait 2 months for that episode you wanted to show to appear in syndication. The way you defeat piracy is to provide a similar and reasonably priced service. People are perfectly willing to pay for a reasonably priced legal content on a streaming service.", "So what's the point in hosting these?\n\nWho makes (any) money?" ] }

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{ "a_id": [ "e18jurx" ], "score": [ 3 ], "text": [ "Not quite your question, but [this older link](_URL_0_) might nevertheless be of interest for you." ] }

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[ [ "https://www.reddit.com/r/AskHistorians/comments/6o6r8x/do_we_have_any_records_of_recreational_drugs_used/dkfkgd5/" ] ]

{ "a_id": [ "elxaeaf", "elxfd0m" ], "score": [ 17, 10 ], "text": [ " > Would the vacuum be strong enough to tear single molecules out of the container walls, or wouldn't it even be possible to create a container strong enough, or wouldn't anything cool happen at all?\n\nThis prevents you from ever actually reaching perfect vacuum. Not from \"tearing apart\" the walls of the vacuum chamber per se, but from *virtual leaks*.\n\nThese are a number of processes that lead to residual gases being present in the chamber even if there is no direct pathway from the outside in (a \"real leak\"). For example, any moisture that has been deposited on the walls of the chamber will outgas. And any air which is trapped inside of little cracks or screw holes, which will take a long time to be fully removed by the pumps. And even *permeation*, where things like helium gas literally diffuse through the walls of the chamber.\n\nAll of these kinds of processes mean that there will be some small amount of residual gas inside the chamber no matter how hard you pump. You can never reach a perfect vacuum in a laboratory.", "/u/robusetceleritas did a great job of explaining why we can't achieve a perfect vacuum. I'll add that the strength of the container really isn't much of an issue. If you were to create a perfect vacuum in a chamber, the pressure difference on the chamber walls is only one atmosphere. We can get to very low pressures, less than a billionth of an atmosphere, so the pressure difference that a vacuum chamber has to maintain is almost one atmosphere anyway. Gases are often stored at pressures much higher than atmospheric pressure, and anything over 2 atmospheres is a greater pressure difference than you could ever achieve with a vacuum. Atmospheric pressure is about 101 kPa or 15 psi which is no problem for just about any metal, the real problem is leak management." ] }

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{ "a_id": [ "c7k8sqs", "c7kaomt" ], "score": [ 20, 2 ], "text": [ "My understanding of how this thing got started (I'm trying to find a citation) is that the number 13 comes up repeatedly in Maya numerology because it's considered a lucky number. The ritual calendar, as you pointed out, uses 13 cycles of 20 days. Using this, the novelist Gary Jennings wrote [a fictional novel](_URL_1_) on an apocalypse based on the B'ak'tun switch. My guess is that some new age nutjob read this work of fiction and decided it was a real prophecy. People then started writing \"non fiction\" books making the same argument.\n\nAside from the fact that the idea has its origins in a work of fiction, and the Maya made no such prophecy, we also place way too much emphasis on the Long Count. I think this is because, of the Mesoamerican calendars, the Long Count is closest to our calendar in that it moves in linear progression from past to present. The other Mesoamerican calendars all move in cycles. This is really a cultural bias on our part. We assume that because it's closer to our calendar that it's 'more advanced' and thus more important than the others. The truth is that the Long Count was only used by the Maya and the Epi-Olmec cultures, and even then it was only used to keep track of dynastic records. The other calendars (like the solar and ritual calendars) had way more relevance to the daily lives of ancient Mesoamericans. And since those are cyclical not linear, they don't ever end. They just keep going.\n\nEDIT: [Here's](_URL_0_) a really detailed breakdown of the whole thing from a reputable source, for those of you that want to learn more.", "Since this is 6 hours ago, i'll give it a try even though i'm not an expert.\n\nOne of the main indications would be that the Mayas wrote the creation date not 0.0.0.0.0, but 13.0.0.0.0. (But numerically it worked as 0.0.0.0.0.) Also, the 13 is an important number, even though i can't say anything about it's specific relevance. But it's also used in the [Tzolk'in-Calendar](_URL_0_), which would be the ritual calendar.\n\nAll that in mind, to what i recall it is correct that in some writings, 20 baktuns are used, as far as i understand, and even counts where the baktuns would be counted upward without end. Sources simply vary on this and this probably implies different systems. Just like the Maya-mythology used common elements but the details varied from city-state to city-state, for instance." ] }

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[ "http://en.wikipedia.org/wiki/Maya_calendar#Long_Count" ]

[ [ "http://www.famsi.org/research/vanstone/2012/index.html", "http://www.amazon.com/Apocalypse-2012-Novel-Gary-Jennings/dp/0765322595/ctoc" ], [ "http://en.wikipedia.org/wiki/Tzolk%27in" ] ]

{ "a_id": [ "chhlhj1" ], "score": [ 8 ], "text": [ "The authorities who should be planning for this are fixed in \"LaLaLa-can't-hear-you\" mode at present, and will probably remain so until their cities are flooded monthly.\n\nKnowing how engineers work, it will probably be large pumps and high sea walls, which are then largely ignored and eventually fail for lack of maintainence, New Orleans style." ] }

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[ "http://www.usatoday.com/story/tech/2014/05/12/west-antarctic-ice-sheet-stability-sea-level-rise/9001819/" ]

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{ "a_id": [ "cmgqxpw" ], "score": [ 3 ], "text": [ "Its noise off the generator or alternator.\n\nCords like that aren't shielded like other people have said. Its basically RF interference coming from that because its often not shielded.\n\nIts usually not something noticed, and the stereo itself has filtering to block it. But when you plug something unshielded into it (your aux cord) you're creating an unfiltered path to the stereo, so you hear it." ] }

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{ "a_id": [ "clyxnaj" ], "score": [ 2 ], "text": [ "It means that Obama put his hat in the ring and took a stance. That being said he cannot compel the FCC to follow what he wants. Basically after using Net Neutrality as part of his platform in 2008, and then staying on the fence about it for a while, he's finally given an opinion. This *could* sway the FCC to fall in line, but that remains to be seen." ] }

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{ "a_id": [ "chftd2h" ], "score": [ 2 ], "text": [ "There were several reasons regarding the fleets themselves: Zheng He's fleets were expensive, the Ming were involved in wars against the Mongols and Vietnamese, the government bureaucracy was quite suspicious of how eunuchs dominated the venture, and the emperors were no longer as interested in the prestige of the voyages. " ] }

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{ "a_id": [ "c68m79x", "c68mjaa", "c68nker" ], "score": [ 2, 2, 2 ], "text": [ "I don't know of too many scientists that have personal microscopes at home. That being said, the ones that my students used when I was TA'ing were $3000 each and I consider those pretty basic. My lab's microscope was in the $40,000 range, and the confocal I used cost $325,000. For under $200 it will be a cheap \"toy\" microscope. Not too sure how great the resolution will be on it. It really depends on what you want to use it for. Cells and tissue for $200? No way. But if you want to look at bugs and leaves up close, $200 would work.", "Like Rodentia said, I don't know anyone that has an at-home scope (except for one friend who collects old broken ones and uses them as decoration). \n\nMy lab's TIRF scope cost almost a million dollars with all the bells and whistles. \n\nFor less than $200, I'd look on ebay and try to find something used. For that cheap, you're probably only gonna get a monocular scope. Also, the objectives will probably be scratched, but that isn't too bad. For that small amount of money, don't try to get super-high objectives. They'll probably suck. Get a 40x or something.", "You could get a chinese webcam microscope similar to [this one](_URL_0_). Ebay has plenty of different models too, but Adafruit probably did enough research to find a good one to resell at their store." ] }

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[ [], [], [ "http://www.adafruit.com/products/636" ] ]

{ "a_id": [ "dq5f554" ], "score": [ 21 ], "text": [ "I can reply to the bank question, but not the stagecoach one.\n\nTL:DR: The bank, unless the robbery caused the bank to fail, in which case both.\n\nHere's how banking works: banks take deposits from people and lend out the cash to other people. The deposits are liabilities of the bank - that is, they owe that money to the depositors. The bank has assets, which are the loans it makes and the (much smaller) amount of cash it keeps on hand. One way to understand this is to think of a gold merchant.\n\nThe gold merchant needs a secure place to store the bullion, so he builds a vault. Seeing this, other people with gold pay him a small fee to store their gold as well. Over time, the merchant notices that the gold at the back of his vault just sits there undisturbed, as people take out and deposit gold, they subtract from and add to the gold near the front. Hey, gold is gold, nobody wants \"their gold\". Once the gold merchant realizes this, he starts letting people borrow gold. For a fee, of course. As long as everyone doesn't demand all of their gold back at the same time, that works fine. The merchant only needs to keep enough actual gold on hand to satisfy the withdrawals. That's called \"fractional reserve banking\" and it is what we have today, as well as what they had in the old west.\n\nSo now along comes a robber and takes the cash on hand. It belongs to the bank, but they still need some cash to satisfy the demands for withdrawals by its depositors. But the amount kept in cash is much smaller than the amount of loans owed to the bank. So, as long as the entire town doesn't panic and demand cash, the bank can replace the cash owed to its depositors from the repayments of the loans it has made.\n\nIf, however, everybody wants their deposits back *right now*, that's called a \"run on the bank\". You don't need to be robbed to have a run on your bank - it happened during the Great Depression, too, which is one reason banks were more tightly regulated afterwards. If the run is serious, then the bank will be closed because the bank doesn't have enough cash to pay all the depositors back. In which case, depositors lose money as well." ] }

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{ "a_id": [ "ffm47l8" ], "score": [ 4 ], "text": [ "I can't answer with specific reference to the Roman Empire although I suspect that much of my answer is transferrable from Medieval skills to Roman skills.\n\nFirstly I'd like to challenge the assumption that \"*knowledge and tools for dog training were much less than we have today*\". A good dog trainer needs no tools other than an understanding of the animal, there's no reason to suppose that people of medieval times understood their animals any less than modern non-technological societies do today - and they do so very well indeed. Veterinary understanding has certainly improved but this arguably has little to do with the skills required for animal training.\n\nThe types of dog used in Medieval hunts are very similar to types that we'd recognise today with the exception of modern \"gun dogs\", a type that has come into usage for the firearm hunting that largely replaced hawking.\n\nMedieval hunts would use Greyhounds, a fast, short-burst game tracker that was safe in domestic settings. Alants were also used, they were a larger, stockier greyhounds for chasing larger game like bear but were unpredictable and considered too dangerous to roam free around homes. Mastiffs were used as hunt dogs and quite often as guard dogs, this large and impressive breed was used on the same large game as the Alant and also as a guard/watch dog. Mastiffs were used as war-dogs, although their usage wasn't common in Medieval battles due to their negative effect on horses, you'd be more likely to see a mastiff used by small armed patrols as a first line of defence/offence.\n\nRunning-hounds were used as game-chasers, the breeds were largely similar to the foxhounds of today.\n\nHow well trained were they? From the ubiquitous use of the different types as an integral part of hunts in Medieval England and Europe it seems highly reasonable to presume that they fulfilled their task very well and therefore that they were trained very well, particularly breeds that were required to silently find scent for the hunting party.\n\nIn short: there are a lot of reasons to think that Medieval animal training was as good as it is today - if the use of dogs spoiled the hunt then their use would have ceased rather than perpetuating for hundreds of years.\n\n & #x200B;\n\n*^(Sources:)*\n\n*^(Royal Forests - Hunting and Other Forest Use in Medieval England; Hooke, D; 2011)*\n\n*^(Hunting Law and Ritual in Medieval English Literature; Marvin W; 2006)*\n\n*^(Hunting for the Anglo-Normans; Zooarachaeological Evidence for Medieval Identity; Sykes, N; 2005)*\n\n*^(Special mention, well worth looking up as a contemporary reference:)*\n\n*^(Livre de Chasse (Book of Hunting); Gaston Febus, Count of Foix; c.1388)*" ] }

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{ "a_id": [ "cz75bd2", "cz75ebp", "cz75n3g", "cz75zbv", "cz78kt5", "cz7ai28", "cz7bds0", "cz7c4iu", "cz7dnet", "cz7dpd8", "cz7ebs0", "cz7eeoj", "cz7fm97", "cz7g260", "cz7g6ni", "cz7g8bk", "cz7gezx", "cz7hdee", "cz7i2sj", "cz7j0sw", "cz7jgq0", "cz7jna4", "cz7k35c", "cz7kdxi", "cz7kocq", "cz7kzvo", "cz7l3mg", "cz7l3nq", "cz7l76c", "cz7lijp", "cz7m1u6", "cz7mdhw", "cz7mw2z", "cz7n3b1", "cz7nusc", "cz7pobo", "cz7ppba", "cz7puh9", "cz7qbfa", "cz7qg4g", "cz7qgti", "cz7qs9w", "cz7r4tb", "cz7r8j2", "cz7re5a", "cz7rgnp", "cz7s2gc", "cz7sg0v", "cz7sn40", "cz7so2b", "cz7stle", "cz7svmp", "cz7tb8a", "cz7u2x2", "cz7va5x", "cz7wtv7", "cz7xlwl", "cz7z5sa", "cz7zbs9", "cz806qo", "cz8142n", "cz83tue", "cz84niz", "cz8521g", "cz8a1cn", "cz8a6d1", "cz8cmuq" ], "score": [ 43, 3056, 176, 29, 4, 1657, 2, 19, 3, 4, 2, 107, 3, 779, 11, 15, 2, 3, 6, 124, 4, 2, 100, 2, 2, 4, 2, 2, 2, 2, 2, 2, 2, 11, 34, 2, 2, 2, 2, 2, 2, 8, 2, 2, 2, 4, 2, 5, 2, 2, 2, 15, 2, 2, 5, 2, 2, 3, 2, 3, 2, 2, 3, 2, 3, 2, 3 ], "text": [ "Bolt action rifles are lighter and simpler than semi-automatic rifles in the same caliber, and bolt action is an inherently more precise action type than semi-automatic.\n\nSnipers don't need to put out a high rate of fire, so semi-auto has no benefit to them.", "I could be wrong on this, but the bolt action rifle would minimize extraneous movement that might alter the trajectory of the bullet. Remember that even small fractions of a degree might be the difference between a hit and a miss, so it's important to keep everything as still as possible. In a semi-automatic mechanism, the movement of the gun as it works to reload a bullet may very well knock your shot off far enough that it would cause a problem. Nothing moves in a bolt action mechanism until you're reloading.\n\nEdit: the bullet has a trajectory, not the gun. Edited for the proper noun. ", "Making a weapon accurate and make it fire rapidly are two competing goals. If you don't have to care about making it fire rapidly, you can make it more accurate. \n\nIt's really that simple. ", "A semi-automatic weapon, upon being fired, has the bolt come back, discharges the shell casing, and a new round is inserted into the action. This motion, which occurs extremely rapidly and uses the force of the fired round causes vibrations in the gun that lead to muzzle climb and loss of accuracy.\n\nA round does not leave the gun instantaneously, as the barrel length increases the time to exit increases meaning the slightest muzzle deviation can throw off your shot.\n\nA bolt action does not have any moving parts in the action like a semi-automatic, while the round is traveling in the barrel. This means all the force is exerted on the round, but also there are no other vibrations from auxiliary parts.", "More moving parts means more opportunities for something to get gummed up or broken. A bolt action would likely hold up to the punishment of being dragged through rugged terrain. The Barrett .50 cal is semi-automatic but it is so big and heavy that it probably won't be taken on those kinds of oporations.", "Semi-auto sniper rifles in US service:\n\n* Various DMRs based on the M14 (M39/M21/Mk14/M25)\n* The M110\n* The SR-25\n* The Barret M82\n\nSo, they're not exactly unheard of in US service. \n\nHell, Carlos Hathcock shot a Vietcong guerrilla at a range of 2500 yards using a M2 machine gun with a telescopic sight mounted on it. That was a record that stood for over 30 years and **he wasn't even using a specially made sniper rifle**. This alone should debunk the idea that there's any kind of inherent limitation to semi-auto rifles that makes them not suitable for long range work.\n\nAs far as why bolt actions haven't been completely replaced by semi-autos in the sniper role:\n\n1. **They work okay.** The disadvantages in volume of fire aren't really that big a deal on a rifle that's set up for long range shooting. Armys tend to be fairly conservative when it comes to small arms, so \"if it ain't broke don't fix it.\"\n\n2. **There are a lot more \"off the self\" bolt actions set up to fire really big rounds**. Rounds like .300 winchester magnum and .338 Lapua were developed from big game hunting cartridges. AFAIK there weren't any semi-auto big game rifles, but there were tons and tons of bolt actions that could be readily adapted into sniper rifles. Why reinvent the wheel?\n\n3. **Cost.** Getting equivalent accuracy from a semi-auto design costs more money. Despite its reputation the military is weirdly tight fisted about spending money on small arms.\n\nI realize I'm kind of swimming against the tide here, but there are the facts as I see them.", "Anything which affects the recoil of the barrel as the bullet passes down it will reduce the accuracy of the weapon. An auto mechanism is a lot of small movements that causes the rifle to wobble slightly, so they are not part of the mechanism. Also really good sniper rifles like the Barrett, have a 'free floating barrel'. Which means it is only attached to the rifle at the base, not along the barrel itself. This allows it to remain as level as possible as the bullet passes down it.", "Also, semi automatic rifles eject the empty shell casing at a high rate of speed. This ruins the snipers cover our concealment.", "Another reason they use bolt action is so they can be sure that the shell casing can be taken out and taken with them. They try not to leave any evidence of them being there.", "Bolt actions have fewer parts moving during fire which contributes to accuracy. Even small movements get really big when you get really far out so this does provide an advantage. On top of this the rate of fire isn't as big of a concern for a sniper. If they decide to shoot twice they want to be able to get the next one out asap but you can't pump rounds downrange from sniper distance like you can with a carbine at short-mid distance. If it's not necessary to shoot more than once many snipers are taught not to shoot more than once; observe, shoot, move, observe, maybe shoot again. Of course that goes out the window if they're covering for advancing troops or things like that. \n\nThe gap has been narrowing though and is evident with all the semi-auto sniper rifles and battle rifles set up for long range and capable of sniping (often the same platforms). It's not that semi-autos aren't good enough and can't preform as sniper rifles because they do, see M14 platform snipers, AR-10 (I don't know that this is in widespread military use but it exceeds standard), the dragunov (although IMO it's not quite accurate enough it is in use), etc. It's that it's easier to get a bolt-action up to standards. ", "My follow up question is why are straight pull bolt actions so uncommon, we've been making bolt action rifles for over a hundred years, surely it's not that hard? ", "I'm not a sniper, but I'm in a scout sniper platoon in the military. First of all most \"sniper rifles\" are not bolt action. Bolt actions are definitely only used as \"sniper\" rifles, however. The US army fields 3 primary weapons for its scout sniper platoons, right now, for long range precision fire. The m110, m107, and the m24. Two of those are semiautomatic. The m107 is 50 caliber, and is used primarily for targets like vehicles. It can also be used for long range fire but it is not the most accurate. The m110 comes standard with a suppressor mounted, and it is excellent for any mid range firefight. It is also a decent precision fire weapon under 700 meters. A lot of snipers shots are not going to be at super long range unless the terrain makes those kind of shots necessary. In heavily vegetated areas 300 meters is actually a pretty ideal range to engage a target. Bolt action rifles are utilized when absolute precision is key. A bolt action weapon is a lot more accurate at range, and is the preferable weapon for what you are thinking of as a \"snipers\" job. You can absolutely use a semi automatic as a \"sniper\" rifle, and we often do in the military. It just depends on what you have, and what you need for each situation. A sniper rifle is more of a designation meaning it can be used to deliver long range precision fire. ", "Not all \"sniper rifles\" are bolt action. I won't even get into the whole \"there are only rifles, and snipers, not sniper rifles\" thing. If we are comparing bolt action to gas operated, it is absolutely true that a given round will have lower muzzle velocity coming out of the gas operated rifle with the same barrel length. This is because a small amount of the gas pressure is siphoned off to operate the action. This happens before the bullet leaves the muzzle. This is why a sniper would choose a bolt action rifle over a gas operated rifle. Even a tiny amount of extra muzzle velocity can make a difference. Currently, snipers use bolt action and semi automatic rifles. The choice comes down to preference, the specific mission at hand, and availability. Chris Kyle (American Sniper) used both bolt action and semi automatic rifles during his war time service.", "Late to the party, and this'll get buried, but I was a USMC sniper deployed to Afghanistan and Iraq between 2007-2010. \n\nMost sniper rifles are bolt-action for two reasons. \n\n1: They're more accurate. Fewer moving parts, fewer things to pull the barrel in any direction. When you're dealing with a target at 300 to 1k+ yards away, even the slightest tick on the barrel will cause you to miss by feet, not inches. \n\n2: Fewer moving parts. More moving parts, more chance for a jam or some other malfunction. When any firearm is gas-powered (using gas from the 'explosion' of firing a round to kick the slide back, eject the spent cartridge, and load a fresh round) as most semi-auto firearms are, it has a great many moving parts. A bit of gunk in the mechanism, wear and tear, or even humidity can cause the weapon to jam and potentially get someone killed. \n\n\nHope I helped!\n\nEdit: Fewer, not less. ", "Sniper here. And yes as a few people mentioned bolt action is the standard because it is a single round at a time that doesn't \"spook\" your aim. \n\nMy instructor in the USMC told me when shooting long range the ignition should sneak up on you. \n\nThey would often say squeeze the trigger so lightly that you're surprised when it goes off. This was so you wouldn't move at all after you were dialed in. \n\nMultiple shots would defeat the purpose and you wouldnt have a clue how to adjust if you missed. \n\nTLDR multiple rounds will move your weapon and make it impossible to adjust if you missed. \nLong range shooting is about dialing in and not moving until after the bullet Is released. \n\n\n", "I'm an FFL and Class 3 dealer with contracts for my local police department. The reason why they're mostly bolt-action is because they have a bunch of them in stock and they're cheaper. There are semi-automatic precision shooting rifles in stock already that the military uses, but they are much more expensive.", "Besides what many have already pointed out about the accuracy and cost of bolt action vs semi-auto, it also comes down to the sniper's job. \n\nBreaking it down Barney style, they sneak around and inflict accurate fire from long(er) distances compared to more conventional forces. This means that volume of fire isn't as important since, after firing a shot, a) the firing position is compromised and you need to relocate, b) firing more than once would give the enemy a greater idea of where the sniper is hiding, and c) the sniper is probably outnumbered (see b). \n\nIn most situations, unless the sniper's position is somewhat in control of friendly forces, the sniper cannot afford to fire more than once in the same position.\n\nAs far as semi-automatic sniper rifles, there are quite a few semi-automatic sniper rifles in the military's arsenal. For example, the [M82A1](_URL_0_) and the [SR-25](_URL_1_). \n\nI hope this adds something to the conversation.", "/u/MysteriousGuardian17 mostly has the correct answer, however, there is a bit more to it. \n\nWith long range weapons, the absolute central importance is knowing how the projectile is going to leave the weapon. Unless you're using [self-guided projectiles](_URL_3_), your chief concern is making the margin of error as small as possible. The projectile leaving the barrel even a millimeter off center can mean meters off target at long ranges. \n\nSo, the *bolt action* is one configuration as opposed to other methods of operation such as, striker fired, gas operated, short/long blowback, and others. [Please take a look at the video on this page, it has a depiction of how striker fired pistols work](_URL_4_). This depiction is really important because it shows something really important, each method of operating a gun system has positives and negatives. The purpose of your gun will determine which is best. \n\nFor a pistol that you want to conceal, striker fired is *in my opinion* best because there is no hammer or other protrusion to get stuck on clothing. But, as you can see in the video, the barrel must move to accept the next round (among other reasons) it is very difficult to have the barrel return *PRECISELY* to the exact same configuration each time for maximum precision. Therefore, striker fired pistols (or any pistol or revolver for that matter) are going to be significantly less accurate than other methods for distances beyond 10 yards. \n\nSo, with bolt action, there are two main benefits: \n\n1) The barrel and assembly are \"free floating.\" \n2) There are almost no moving parts. \n\n[Watch this video of how an M16 works](_URL_0_) - it is fascinating. The M16/AR15 weapon platform is absolutely the greatest semi-auto weapon there is (vastly [superior to the AK47](_URL_2_) ) and in the function video of the M16, you can see the gas system, the trigger group, and the bolt cam action - those three moving parts (well, the gas operation isn't a moving part, but it is something moving) are going to cause problems. \n\nTake an extreme case of a weapon that fires from open bolt. Almost no rifles fire from open bolt because it is a dumb idea: When you pull the trigger, the bolt then moves forward, chambers a round, goes into battery, THEN fires... Wherever you were aiming when you pulled the trigger is no longer where your muzzle is pointing. \n\n**By the way, if you want to skip ahead to the answer, it is here:** \n\nTo a vastly less degree than an open bolt rifle, a semi-automatic weapon has a few moving parts that a bolt action doesn't. The trigger alone in a semi-auto weapon has to go through a few hoops before the firing pin is actually struck, [look at this animation of a bolt action rifle.](_URL_1_) There is almost no movement of anything between the time the trigger is pulled and the time the firing pin strikes the primer. With fewer moving parts comes a smother and shorter trigger pull and less movement of your muzzle, remember, even a millimeter of movement in your muzzle can cause meters of error at the target. \n\nFinally the free floating barrel permits higher tolerances for the machined parts in the barrel and bolt. So the bolt brings a round into battery almost identically each time. With weapons that are designed for higher rates and volumes of fire at closer ranges, the tolerances aren't as important (the AK 47). \n\n**TL;DR:** The bolt action has fewer moving parts and functions with greater precision. When you're trying to hit a half meter target at a mile away, you need to have the cartridge sitting just the same each time, a very small and soft trigger pull, very few moving parts, and no warping between the barrel and the stock. ", "The semi-automatic uses some of the energy from each shot to chamber the next round while the bolt action puts all the energy into propelling the bullet. This means with all else equal the bolt action projectile will have slightly more kinetic energy which can make a difference at long ranges.", "Scout sniper here. Regarding prevalence of bolt action rifles: fewer moving parts, tighter chamber tolerances, and recoil management.\n\nFewer moving parts = fewer malfunctions (extremely reliable)\n\nTighter chamber tolerances = less energy wasted from gas release (among many others)\n\nRecoil tends to be more predictable and easier to manage because the bolt is not automatically cycling through the order of operation after a trigger pull.\n\nFree floating match grade barrels, custom stocks, custom optics calibrated specifically to the rifle, etc. are other perks.\n\nYes, I have employed the M110 Semi Automatic Sniper System extensively, so please don't tell me about the greatness of semiautomatic sniper rifles. I prefer bolt action rifles for the sniper role, but the semiautos are excellent in most situations (and often more appropriate ie urban).\n\n\nEdit: the \"less energy wasted from gas release\" portion results in increased muzzle velocity, due to more gas expanding within the barrel itself and pushing the bullet out with more energy. Most semi auto rifles are gas operated, indicative of gas not exclusively being used to propel the projectile but to cycle the bolt.\n\nOne last thing: this is not always true, but many bolt action rifles have a longer barrel length than their semi auto counterparts. Longer barrel length allows more gas to stay behind the projectile longer and yields higher muzzle velocities than shorter barrels. This is why suppressed rifles have higher muzzle velocity than unsuppressed.", "Because in real life gas ejection systems for semi automatic guns jam, and unless you physical pull back the slide of the ejection mechanism you can't see if the round is seated properly. \n\n\nSometimes it's an obvious jam... Maybe the shell gets caught in the slide, or the magazine is old/a little off and the spring tension didn't push up hard enough and you have a half seated round. \n\n\nJams happen more in extreme weather, too cold or hot.... Rounds will stick and not seat. \n\n\nAnd a semi automatic has more failure points to create inaccuracies. This is because the firing sequence is 8 steps, which all but 1 (pulling trigger to send the hammer) is performed by Springs and blow back gas. \n\n(Feeding, \nChambering,\nLocking, \nFiring, \nUnlocking, \nExtracting, \nEjecting, \nCocking) \n\n\nThis means the gun will be VERY sensitive to the ammunition in order to properly run 7 steps. \n\n\nIf you watch match shooters, they'll often manually drop in rounds directly through the ejector. Why chance it if you only get ONE bullet. \n\n\n\n\n", "So just to clarify there are plenty of semi auto sniper systems on the market. The us military uses the m110 SASS. Modern technology there is not a whole lot different between bolt guns and semi autos. Tolerances are right enough for what most snipers do, which is minute of person. One big catch is as a sniper, concealment is the difference between life and death. A bolt system the shooter can control when the empty case is removed and can even do it slowly shielding the case from view. In a semi auto the case is automatically ejected and a single glint from that can cost them their lives.\n\nNow that said bolt guns will always have a very slight advantage because a lot of times you want velocity. All semis use some form of the energy to run the bolt back this reducing the velocity of the projectile.\n\nBolt rifles also have a lot of moving parts so getting the same consistency is hard. Something often said for long range shooters is if you are consistently wrong you will still be accurate. IE as long as you do everything the same you will put the bullet in nearly the same spot. A semi the bolt grabs the round and throws it forward causing inconsistent pressure every time. In perspective accurate shooters load ammo to to overall lengths of .01 inches of each other. The bolt catching the round and slamming it in can cause a slight setback and when we're talking .01 inches it's not a lot of variance. This accuracy is not for snipers, this is for target shooters though.", "SUPER late, but there are so many completely wrong answers, even from actual ex-military. There's only a few *partially right* answers out of the dozens I scrolled down through. The best I saw was only at +5, from /u/macguyvers_dad, though a lot is left off. (I can't remark on reliability, but just the physics)\n\nI'm surprised no one but that one person has mentioned that you get a higher muzzle velocity with bolt action as you aren't wasting exhaust gases to move back the bolt and chamber a new round. \nA few had partially right answers, noting the tighter tolerances you get, but not the desirable effect that gives of higher muzzle velocity. \nHigher muzzle velocity means the bullet reaches the target faster, drops less, and you have to lead less. This is what people might mean by more accurate, but where really incomplete in their description of how and why.\n\nThat's one of the biggest reasons.\n\nA .50cal has so much energy that it's not a big deal, and that's why most semi-auto sniper rifles in use today are .50cal, whereas a less powerful round sacrifices too much in the way of ballistics to be semi auto.\n\n**So the simple answer is:** muzzle velocity. A faster bullet makes it easier to hit your target from far away. Bullets aren't like lasers. An M16 (assault rifle) has a muzzle velocity of 853 m/s.\nWhen trying to hit something 2km away, there is quite a bit of time before the bullet reaches the target even at around 1000m/s that you get from most sniper rifles. 1000m/s is just the speed at which it leaves the barrel and it slows down. Muzzle velocity is very important, and a bolt action rifle will use the most of that catridges charge to propel the bullet forward.\n\nThe .50cal semi auto rifles are also only around 853m/s muzzle velocity, but because the round are so heavy they hold that velocity for a long time.\n\nedit: I gave the impressions of it ONLY being about the mechanism that affects muzzle velocity, when that's not true. Sniper rifles also tend to use higher power ammunition and longer barrels to match. I replaced it with a comparison using the same ammo.\n\n---\n\nPeople are saying less moving parts making them more accurate, but that's not really true because the bullet leaves the barrel before the bolt finishes kicking back in a semi automatic.\n\nPeople saying how the motion of chambering the new round disrupts the first one leaving the barrel are just wrong and don't get how fast this is all going on. The slowest part is getting the next round into the chamber, which **does** happen in almost every gun *after* the recoil reaches the shooter's shoulder, but this has no effect in a sniper rifle and is just what causes the second shot to be off in fully automatic weapons. With a semi auto sniper, you have plenty of time to resettle before pulling the trigger again. \n\nThis is all really simple and intuitive when you know how guns work. I'm surprised no one gave the answer earlier that I can see.\n\nIf you find a video of a super slow motion sniper shot, you'll see the gun doesn't move until after the bullet leaves the barrel which completely busts what most of the answers said.", "In addition to what other comments state regarding accuracy, a bolt action rifle will have higher muzzle energy (note: holding constant the ammunition and length of the barrel) than a semi-automatic weapon. In a semiautomatic small arms weapon, some of the energy from the cartridge is diverted to operate the reloading action. In a bolt action, ALL of that energy is behind the bullet.", "Basically they like to control the speed and instance the brass is ejected from the chamber to avoid being detected, on top of that most designated marksman rifles like the [SPR](_URL_0_) just don't have the same accuracy as any bolt action sniper rifle like the [M24](_URL_2_).\n\nSource: Was Designated Marksman in Infantry squad and used [M14 EBR](_URL_1_)", "The simplest explanation I can give (others here also hit it on the head) is that a semi auto action has a moving mass inside. Any tiny movement at the muzzle is exponentialy larger at the target (think of a cone or an accute angle, the rife sitting at the vertex). The movement of the action, a breath or an uneven trigger pull can throw off the shot by a millimeter at the muzzle and feet at the target. In a semi auto rifle, after the shot breaks you have the recoil from the shot and then (slightly later) a smaller backward and foreward recoil from the action cycling.\n\nA bolt-gun has two moving parts, the trigger and the firing pin. With a steady hand and an ideal shot the rifle would move once with the shot. There is just less going on to compensate for. It would be like drawing with a standard pen vs. a pen with a swinging weight on the end.", "A lot of the reason people think this is because that's the way they are portrayed in video games. Because they need a tradeoff in video games, sacrifice accuracy for firing speed.\n\nIn the real world there is nowhere near as much difference.", "Energy from a fired round is used to to re-set semi auto weapons via blow back. With bolt action 100% is used to power the round to the target. The main reason however is that bolt action weapons are built to finer tolerances where as semi auto's have a lot less tolerance to insure they don't jam.\n\n_URL_0_ Here is an auto weapon firing a single round in slow mo and as you can see there is a lot of movement including the barrel which will degrade accuracy.", "Well, for one, it is extremely difficult to hit a target at long range in quick succession, so using a semi-automatic rifle would have no tangible benefit in that regard. With most long distance shots, you have only one chance; you have to take into account elements, sight your rifle without any practice shots, and may have a very limited field of view. If something is wrong with your shot, your target will likely move, or be moving, making your next shot exceptionally harder, if not outright impossible. Doing all of the above is a lengthy process, and not something you can do after a high-powered rifle shot, so having another bullet ready to go in a fraction of a second is useless, because *you're* not ready. Precision shooting is slow; careful breathing, a slow, smooth trigger pull.", "Another reason snipers prefer bolt actions over semi-autos is for stealth reasons, in regards to cleaning up a firing position or hide. \n\nIt's easier to collect brass out of a bolt rifle than a semi-auto one since you can eject the spent casings into your hand and put the brass directly in a dump pouch versus going all around a five foot area picking brass up off the ground. It's important for those long range recon missions to leave no trace of their position after they're done using it", "The action on a semi-auto (even though it's slight) does degrade accuracy. At 400-500+ yards, just one minute of angle off target is a 4\"-5\" error and in sniping, that's huge. \n\nAnother reason for snipers using bolt actions is sound. There are five factors that cause sound when shooting. The discharge of the round, crack of the bullet breaking the sound barrier, action of the rifle, the brass hitting the ground and the projectile striking the target. \n\nWith a bolt action, you eliminate the action sound and the brass striking the ground. A sniper may use a suppressor which would help with the discharge sound. However, it's not like you see in the movies. Even with a suppressed bolt rifle, there is still a lot of sound once that trigger is pulled. If you ever shot a 22 LR, a suppressed sniper rifle still has that many db's or more. Sound=Bad for a sniper.\n\nThey are not shooting subsonic ammunition for long distance so the crack of that bullet breaking the sound barrier is unavoidable. \n\nThere are other factors but accuracy and stealth are key. ", "Same reason many car drivers prefer manual over automatic - more control over many variables.", "Doing so would mean spending propulsion force to move the reloading mechanism. \n\nSniper riffles are useful for high precission and long distance hits, so sacrificing automatic reloading for extra firing distance sounds like a good design choice", "because semi automatic snipers take 3 hits to kill, and bolt action take 2. or 1 if youre on a hardcore server.", "This is totally going to be lost in the literal shit ton of bad information going around right now.\n\nThe simple answer is that it's what the sniper community demands. The self-image of a sniper is working in 2 man teams, taking out a target, and quietly slipping away. So per-shot accuracy is prioritized at all costs.\n\nModern sniping started with the military shooting teams. Carlos Hathcock was a USMC shooter. The rifle he used in Vietnam was the same as the rifle he used to win the Wimbledon trophy. The Army sniper up until the 90's was the M21, which was a national match M14 with a scope on it.\n\nIraq and Afghanistan changed sniping in two different ways; at least for the Army.\n\n It showed that the concept of 2 men going out alone armed with bolt actions was a dated concept as far as urban warfare is concerned. When your firing position had to be in a city that is occupied by unfriendly civilians, it is almost impossible to stay concealed for long. The battles we were getting involved in required that teams be able to stand and fight to a greater degree, so team size typically got increased to 5 or 6 guys to increase their firepower.\n\nThe other thing that Iraq showed is that a bolt action rifle is not the best tool for the job. The added precision of a bolt action cannot make up for the lack of firepower that a semi-automatic can provide.\n\nAfghanistan on the other hand showed the other extreme. Mountain top to mountain top shots across basically devoid terrain. The top 3 longest record sniper shots have been in Afghanistan. One from an Australian team, one from a Brit, and another from a Canadian. In Afghanistan, the 7.62 NATO M24 proved lacking the range required for many of these engagements.\n\nAs a result of experiences in Iraq and Afghanistan , the Army adopted a 2 rifle solution. A semi-auto general purpose sniper rifle in the M110, and a 300 Winchester Magnum M2010 that pushes their effective range out by about 400 yards. The effects are two-fold; a M110 equipped spotter can comfortably handle targets out to 800 yards, and what used to be considered a difficult long range shot with the M24 is more routine with the more powerful M2010.\n\nThe bolt action still has a niche to fill in large caliber magnums for the militaries of the world. They are proven to be accurate and reliable, which is important for extended long range engagements. ", "SDM checking in:\n\nYou guys covered a lot.\n\nI Can at least contribute the idea that a/the semi automatic platform of increasingly higher caliber has scaling recoil due to the amount of moving parts and action. \n\nOften times the larger the caliber, the larger the round, the parts needed to cycle the round also go up in both size and complexity. Where-as a bolt action system is largely a universal concept and scales easily enough to almost any system and almost any round. \n\nSemi Automatic designated marksman rifles almost always cap out in size with the 7.62x51 and 7.62x54 rounds for conventional usage, as beyond that the machining required gets bigger, heavier and starts to defeat the purpose as a designated mobile platform for small unit anti personnel use. \n\nThe semi automatic capability allows for rapid fire to enable suppression and a larger combat capability rather than one shot, precision systems. ", "The bolt action was always considered to be the best choice because when the bolt closes exactly that same way every time and when it is closed the entire receiver assembly is locked up and more rigid than a semi auto.\n\nAlso when it comes to ammunition a lot of serious long range shooters load their own ammo, when seating the bullet they seat it \"long\" so when it is chambered the bolt pushes the bullet into the rifling in the barrel, so every round fired starts from exactly the same place, this can't be done with a semi auto.\n\nAs semi autos have evolved they are getting closer to the accuracy of a bolt action, but the best semi auto still won't beat a bolt gun on paper.", "Purists will give you a variety of reasons, the primary of which is \"variability\". A semi-auto's cycle involves bolt release outside of the user's control, uncontrolled ejection of the casing that can give away position, variable gas utilization for driving the bolt, slapping the next round into the chamber in a rather uncontrolled manner, continued barrel vibration between shots, heat variability of the chamber and barrel and a host of other factors that simply aren't present in manual bolt system. There's also the issue of specialty loads, which can only really be used with consistent results at the technical limits of the weapon in a manual bolt-action rifle.\n\nHere's the reality: semi-auto condone undisciplined sniping. A good sniper will use a single position, ideally, for a single shot, but more realistically, for a couple. Then they will move to another position if their cover is good. semi-autos tend to force position choice into a single defensible position possibly with a good exit route. At that point, you're not a sniper, but a rifleman. A semi-auto rifle can turn a sniping into an ambush, which are two completely separate things.\n\nA disciplined semi-auto sniper will tell you that a bolt-action rifle is inappropriate on the modern battlefield and, as long as the sniper is cognizant of his weapon's limitations and weaknesses, disciplined semi-auto sniping is just as effective as the bolt-action variety. ", "I am just guessing but doesn't the energy needed to cycle the rifle take away from the energy that goes into sending the bullet downrange?", "I am way late and there are a bunch of good answers but one thing they seem to be misrepresenting to the uninitiated. \n\nWhen we are talking about accuracy we mean something more like consistency. Your accuracy with long range rifles is basically dependent on your ability to perform consistently and your knowledge of how your rifle performs in similar conditions.\n\n \"Snipers\" will keep a book or a history filled with shots from their rifle fired in all kinds of conditions (temp, humidity, wind), at all kinds of ranges and even at different angles of elevation. Bolt action rifles lend themselves to consistency much better by design. \n\n\nFirst with bolt action you don't have to use some of the gas to cycle the weapon. This means you get better muzzle velocity which causes the bullet to drop less, make it to target faster giving the wind less time to act on it and means you need to lead a target less. As a general rule, the slower a bullet is moving, the less consistent its point of impact is. (this can change based on twist rates in your barrel and other factors but in normal circumstance is true) \n\nSecond, because the rifle doesn't need to cycle on its own or quickly, every fucking thing in it can be built to much much tighter tolerances. At the distances we are talking anything can throw that bullet off target, specs of sand or dirt, a particularly cold pocket of air etc. The chamber can be built to seat and seal extremely consistently, there is a lot less chance of getting crap in it because you control the cycle and it isn't kicking up a ton of dust by expelling hot air while it's doing it. The tolerances make so much of a difference that a lot of really good marksmanship schools will teach that when you're shooting a really nice bolt action to just put it firmly in your shoulder pocket and only use a couple fingers touching the gun to pull the trigger. However, when shooting a semi they will tell you to crank that mother fucker into your shoulder like it's your job trying to tighten the tolerances and man handle that grip to torque it down even more. \n\nAnother nice thing about them is they are cheaper to manufacture so you have more money left over to use better materials in the stock or\nbarrel. There are also a lot more customization options for bolt actions since they are a much simpler design. Bedding blocks, better chassis, etc. ", "Bolt actions tend to be more accurate than semi-automatic rifles.\n\nThey also tend to get a bit tighter seal, so their muzzle velocity can tend to be a bit higher.\n\nBolt action is preferred over lever action because a lever is more difficult to operate from a prone (laying down) position, or in a trench.", "I'm not just late, I'm extremely late, but I haven't seen anyone mention a very big reason.. In the British military, we use the L115a3 (L96) which as most of you probably know, is bolt action. \nWe have to remember that one of the best features of a long distance marksman is being hidden, and undetected from the enemy. Now if we use a semi automatic rifle, all of the effort hiding and concealing your position could be ruined by a highly polished bit of brass being ejected a meter or two out of the rifle, that goes against all 7 S's of concealment. \nNow that we have a bolt action, we can manually remove the round from the weapon, slowly and hidden. \n", "This topic has already been pretty well beaten into the dirt by the top comments, espeically that there's many semi-auto and even full auto \"sniper rifles\" out there.\n\nBut a couple other reasons I've heard over the years for why bolt-actions are still popular in that role would be:\n\nBolt action allows you to eject the spent casing at a moment of your choosing, whereas any type of auto will eject it automatically. I guess this is sometimes preferable if you don't want brass flying around, potentially giving away your position.\n\nAlso that bolt actions are simpler, and therefore easier to assemble and disassemble, which may be handy if you're crawling through a mile of mud to get to a shooting position. \n\nI have no idea how true either of these really are, just some other things I've heard.", "Not sure how relevant this is, but for a long time it was cheaper to produce accurate bolt action rifles than it is to make semi automatic rifles. this is probally a large part of why scoped rifles were originally bolt action. \n\nA few points to consider\nSeveral early semi automatic rifles ejected cases upwards. This made for poor usage while scoped as cases can strike the scope, however this was fixed by side mounted scopes for some guns. \n\nEjecting the brass is not always a great idea. It does alow for a quick follow up shot, but it also means you have to find the brass before you move, provided you are worried about someone finding said brass. Brass is also quite reflective and in sunshine it could stand out. \n\nBolt action is a very accurate breech mechanism.\n\nBolt actions are not slow weapons to fire when you have been trained with them. when you take into account the amount of time you will spend lining up a shot, Firing the shot, Re aiming for follow up, and firing again, the bolt action is only just behind the semi automatic in speed, as unlike call of duty you can quite easily pull a bolt without coming away from the scope. \n\nAs someone else mentioned there are many brilliant semi automatic sniper rifles. I think a lot of it comes down to the snipers personal preference and availability. \n\nIF you spent your whole child hood shooting cans with a bolt action .22 then a bolt action might come more naturally to you. If you learnt to shoot with semi automatics then that might be the style you prefer. \n\nIf you are a sniper from Afghanistan then chances are your weapon of choice will likely be the Dragunov for its availability in that part of the world, but if you are a sniper from Australia who learnt to shoot with a .303, chances are you will prefer a bolt action. \n\nThe military from most countries likely has several \"Sniper\" rifles available for different missions. As a marksman part of a squad one of the M14's DMR cousins is probably a better option than a long range bolt action rifle as its more adaptable to changing situations. If your job is to watch a crossroads for a week, then chances are you will be looking for something accurate and easy to move if you are spotted. If your job is to cover a convoy from 1000 metres where you will need to disable pursuing vehicles, then you are probably going to want a heavy duty bolt rifle that fires a round as big as your fist. \n\nSo basically it comes down to personal preference, Availability, and the target. Horses for courses. Your not going to send a guy with a .22 to shoot at tanks, and your not going to send a guy with a .50 to jog through buildings as part of a squad. \n\n", "A large part of it is the tolerance difference between a bolt action, a semi-auto and the ammunition they use. By their nature, semi-auto rifles need looser tolerances compared to bolt actions because they have more moving parts that need to move a certain way for correction function. By comparison, a bolt action is a much simpler movement and it is operated by hand which allows for reliable function with much closer tolerances.\n\nNow part 2 of this is the ammunition. When you fire a round, the case expands outwards to meet the walls of the chamber of the rifle. This means in semi autos, ammo needs to be sized smaller than the chamber to ensure reliable function. In a bolt actions, rounds can be used that are perfectly sized to the chamber because they can be manually placed into the chamber and the action locked on the round. Precision and competitive long range shooters very frequently use brass from rounds they have fired in their rifle and reload them without resizing the body of the brass. Only the neck is resized and trimmed to specific sizes. The idea is to produce ammo tailored to the rifle firing it. ", "The ELI5, \"simple\" answer is that **bolt action rifles are simpler, lighter and more robust**. Because long range shooting is about *accuracy* (not volume of fire) the main advantage of automatic loading (increased firepower) is unnecessary at distance and the added mechanical complications only become a potential liability. \n\nThere are certainly semi-autos capable of phenomenal accuracy @ 1000m+ but those guns are more *expensive* and *heavier* than a comparably accurate bolt gun. That's it really. ", "There are a ton of semi, and even fully automatic rifles that can be used for longer ranged combat. Bolt actions just have advantages that other guns don't have for snipers.\n\nOne of them being, in a bolt action you can manually remove spent ammunition.. This means you don't have to worry about flying brass giving away your cover. Believe it or not that is an actual problem snipers have, especially when enemy snipers are looking for them.\n\nSecondly bolt action weapons are usually (emphasis on usually) a lot less likely to jam due to sand, mud, water, etc and prolonged periods of being in dirty conditions. \n\n", "Ah I do enjoy the occasional front page gun thread. Nothing like hearing from call of duty commandos for a day or two. ", "Top comments have it mostly right, but I think it needs some clarification. As with most things in the military, it is part form/function and part psychology.\n\nThere are plenty of sniper rifles that are not bolt action. In fact many militaries use rifles that do not fall into the traditional bolt action type.\n\nOther posts are somewhat correct in that high accuracy rifles tend to try to avoid changes which may effect the ability to put the bullet in the same place. This is the core idea behind accuracy. \n\nAll weapons have certain tolerances that give the weapon the ability to load the cartridge and fire the round. This includes how the the cartridge is loaded, how the weapon detonates the round, and how the round travels down the barrel. Very small tolerances can cause the rifle to be prone to jamming or fouling, which is naturally not a desirable characteristic for a battle rifle. It isn't as much as an issue for dedicated sniper weapons that receive lots of love from the owner. This is not to say it isn't an issue, as snipers still need the weapon to function reliability, but tend to favor higher tolerances which minimize small deviations in how the weapon fires due to the tolerances within the weapon.\n\nAutomatic weapons tend to have have larger tolerances to allow the weapon to cycle properly, but this is not always the case. Some highly accurate special made sniper weapons have high tolerances and little to no deviation in the cycling of the weapon.\n\nBecause bolt action weapons rely on the operator to accomplish cycling the round, there is some reduction of the movable portions of the rifle, which some believe decreases the variables when firing. This is dubious however, and there are plenty of examples of how this can be done just as well by the weapon and minimize movement of the operator allowing easier follow up shots, more on this later.\n\nThis is not to say however that weapons with wide tolerances cannot be very accurate. Periodically even a rifle with wide tolerances will come off the assembly line highly accurate, but even disassembly for cleaning can alter this.\n\nThere is a belief in the sniper community, especially in America that you need a one shot kill sort of mentality and weapon. As such especially for newer shooters it is emphasized that they make every shot count. This is partially due to the expense of the ammunition and partly an inherited cultural trait within the community. It ends up being a bit of a construction of the community which weapons are called sniper weapons and which are called scout weapons, which may be just as accurate but automatic.\n\nSo there you go, it ends up being less important how the weapon operates and how we have learned to view non automatic weapons.\n\nTLDR: There are many sniper weapons that are not bolt action, it comes down to preference within specific parts of the community that have shaped our impression of what constitutes a sniper weapon.", "I am very late to this party!!! I am a prior member of special operations. A few of the top answers are hitting close and getting things accurately however missing a big point. \n\nBolt action rifles were preferred by my group because they were rarely in a position where there job was cover fire. When we would go on an OP where combat was guaranteed to happen everyone carried semi-auto/burst weapons. 1 person usually carried a fully automatic depending once again on the OP. \n\nSnipers in the field are rarely there to kill. I've been on numerous missions where we approach over X-Time get into position watch for X-Time and then leave over X-Time. We crawl we take cat litter to piss in and put feces in bags. The whole purpose of us to be there without \"ever being there\". If we fire a shot in those scenarios you can guarantee we take our shell casings with us when we go. With a semi-auto you lose track of casings because WHO THE FUCK CARES YOU'RE BEING SHOT AT!!! Have you ever field called brass? It fucking sucks imagine having to do that in hostile territory..... It's not happening. \n\nA Snipers job now a day isn't go an assassinate targets, It's go sit and fucking watch and report. They are the eyes in the field. So for the short answer is control. We need to control everything when we aren't supposed to be somewhere. If you are actually called to take the shot you take that fucking brass with you. Another note in that situation where you take the shot is brass shines. If it ejects without control it's going to hit the sun and cause a flash. Most the time people aren't looking in the weeds for a sniper but after a dude falls around you without notice EVERYONE is fucking looking for any indicator. \n\nThrow away because I don't broadcast this to people on a regular basis and don't need it tied to me.\n\n*Sorry I dont know how to edit\n\nTLDR - To control your environment not just your shot", "Sniper here- \rSemi-autos are great weapons, but when extreme accuracy is needed they have one specific flaw. They require gas to move the bolt, extract the previous cartridge and chamber the next round. These gases can vary from shot to shot- minimal change, but enough to notice. Bolt actions are more consistent because all gas is exerted forward, and not recycled for the function of the weapon. The shooter manually does the extraction and chambering. This leads to greater recoil felt by the shooter, and also greater accuracy. There are other factors such as volume of fire, but a well trained sniper can have comparable volumes. Sniping is about calculating, and minimizing variables. Gas/chamber pressure included. ", "Late, so not going to write too much.\n\nI was ranked 4th sharpshooter in my country, many years ago. used almost exclusively [this rifle.](_URL_0_). It looks plain, but it is considered one of the, if not THE best competition rifles in the world. Accuracy of sharpshooting (paper targets) is on a different scale of sniping (shooting people). In a competition, your bullseye is 0.22\" (same size as the bullet), is at 50 M, and you need to put 60 bullets in it, within an hour (there are variations, but this is the standard). for every bullet dead-on you get 10 points, for every MM outside the bullseye, remove a point. my personal best was 597. Enough background.\n\n1. Simple construction, less moving parts, meaning a bolt with a tolerance of 0.001 cm or less. No gas leakage, no slight movement of the round within the chamber.\n\n2. No recoil. All the gas is used for pushing the bullet out the barrel, and no piston traveling back, causing a barrel jump.\n\n3. Barrel needs time to cool down anyway. Hot barrel means a slight change in how the bullet comes out. Also, there is this thing called whipping; after you shoot, the barrel whips, and needs time to straighten again (think a garden-hose, when you suddenly open the faucet, will whip).\n\n4. No need. You don't need to shoot fast, you need to shoot straight. This is better done with a bolt, although there are some rifles using clips and bolts, no need to change what works so well.\n", "sniper rifles require maybe one shot in 10-15 minutes, depending on the situation, making it semi automatic doesnt add more than it removes", "My mostly uneducated thoughts on this are;\n < 1000 yards a semi automatic is preferable. Within 600 a follow up shot is quite possible, the SA will be faster. Rounds designed for this range have well established SA platforms to build from. Bolt actions are incredibly simple, and much easier to develop for niche cartridges. Under about 400 the motion of working the bolt could give away your position. After the first shot people will be searching for flashes of movement. \nOver 1000 yards the advantages of a bolt gun start to out weigh the disadvantages. Slightly more consistent head spacing of the chambered round starts to become a factor. Speed of follow up shots is slow no matter what. The military doesn't need 3 million 2000 yard rifles so there's little incentive to invest the time and money in developing a SA platform when custom bolt rifles can be designed much more quickly. SA's need to prove their reliability over years, bolt guns just plain work. Rounds that are effective at these ranges need to be re barreled frequently, which is a lot simpler with no gas tube. True free floated barrels are significant at these ranges. ", "Semi Auto Sniper rifles are terrible compared to Bolt Action, when trying to quick scope. If you try to quick scope with a semi auto sniper, you will look like a noob, so all the Faze members use Bolt Actions ", "A bolt action is simpler to manufacture, as well as if made semi automatic there's the need of a gas chamber which is unnecessary added mechanical mechanism and weight. The point of a marksman rifle is to be of a larger caliber, accuracy and mobility. Having a gas chamber means that for a larger caliber the firearm size has to be overall increased.\nBolt Action rifles are well known for their pin-point accuracy, simplicity of cleaning and maintaining, a simple firing mechanism and easy to carry ", "Easy answer.\n\nBolt action rifles can be machined to tighter tolerances than semi-auto ones can. Tighter tolerances ensure that the round is chambered exactly the same with little variance. In addition, less moving parts equates to a less complex mechanism. Thus, higher reliability. \n\nThis is important for consistency. Which is why serious reloaders are all OCD types who weigh out brass, powder, tips and primers as a sorting process. Trimming and seating are measured down to the .01 and sometimes the .001 range. \n\nMany tight tolerance semi-autos can do .5 MOA. Whereas a match level or custom made bolt-gun can do .25MOA or better. \n\nFor those who don't shoot, that's a difference between a half inch grouping at 100 yards vs a quarter inch group. Scaled out to longer ranges, it equates to a base five inch spread at 1000 yds vs a 2.5 inch spread. \n\nSource: I'm one of those OCD reloader types who shoots bolt guns when accuracy is a must. \n\nThe decision to go with a bolt-gun vs a semi-auto is a tradeoff between accuracy and capacity. While a semi-auto isn't as accurate as a bolt gun, you can put more rounds down-range in less time with decent enough accuracy. ( Decent meaning ~1 MOA ) ", "because when you quickscope someone, the sound of loading up the next round is much more satisfying", "Saw some mistakes here.\n\nMy guess is weight, the action of a gun is rated by how much force it can take from a bullet in firing. Bolt action probably can handle more force per weight than semi. The standard assault rifle fires significantlyrics smaller rounds than a hunting/sniping rifle.\n\nYou can't see if you hit targets anyway because the recoil, that's why you need a spotter who can see the vapor trail of the projectile to tell you to adjust course..\n\nI was told by an ex Ranger sniper the rifle is pretty cheap, but the glass scope on top cost 5x the rifle. Don't think it cost.\n\nThe 50 cal sniper semi auto has it's place, but it's heavy as fuk for a lot of purposes. Weight matters when you have lots to carry and want to be stealthy. Google the die difference. There larger and faster round is more accurate, but you don't need to shoot 2000 yard targets all the time.\n\nHuge rifles are impossible to shoot standing, and harder kneeling than smaller ones. That makes smaller ones are more accurate and therefor deadly if you don't have a stationary position with time to set up. I went hunting with a 7mm Mauser while my buddies had magnum rifles. There rifles weighed twice mine, and we're very awkward to carry around. \n", "Hi there! Army vet. here. \n\nIn short... Most are not bolt action rifles anymore. The Barrett M98B, Barrett M95, M21, M110, US Army SDM Rifles, Navy MK12, M25, and USMC DMR sniper rifle are all Semi-automatic.\n\nThere is no real advantage to a bolt action rifle over a semi-automatic if both are machined with the same tolerances in the chamber and barrel. The bolt and the recoil system have little to no impact on weapon accuracy which is why most if not all sniper rifles in the US military are now semi-auto. \n \n\n\n\n \n\n\n\n", "I believe a lot of what people are saying about less moving parts means less chance to screw up your shot. It's also true about keeping costs down when manufacturing - more of a \"They don't need it, so why make it\" type of thing.\n\nBut also keep in mind this. The biggest reason Sniper Rifles are bolt action are because they are ***simple***. \n\nSnipers tend to be isolated and remote. They aren't with a bunch of other guys who have spare parts. Bolt action rifles are simple, reliable, and easy to maintain. What good is a gun if it breaks on you, especially if you're supposed to be covering guys a couple hundred yards out? ", "A bolt action does not need gas to push the bolt back so that gas/energy can be used on the bullet. Plus bolt action is way cooler.", "One of the key issues missing here is the projectile deformation from semi-auto actions. If you ever manually eject the 2nd unfired round(after firing the first), you'll notice the HPBT is somewhat deformed/damaged. This is personal first hand experience with an older variance SR25 that I used. If you're engaging at 100-500yrds, it doesn't make that much difference but past that, the flight path of the bullet is severely affected. Also, semi guns tend to be heavier so that's another trade off. \n\nMy personal opinion, if it's a target rich/semi urban environment and I'm reasonably near supply/wheels, I'll hump a semi. Reason being, I'm engaging multiple targets quickly and it's in closer proximity. AFG type, I'm using the bolt gun as the shots are much farther out and the 1/8 - 1/4moa accuracy will mean the difference btw hit or miss. ", "The most obvious reason is that a bolt-action rifle has fewer parts that move during firing, so it throws the shooters aim off less. ", "The way semi-automatic guns work is that part of the force of the explosion goes backwards, to force the action open and chamber the next round. With a bolt-action, all the force of the blast goes forward into propelling the bullet, making it fly faster and straighter.", "Accuracy is a function of repeatability. The whole object in obtaining \"accuracy\" is to make this shot the same as the last, and the next shot the same as this shot.\n\nThere are a shit ton of shot to shot variables with a rifle, and the projectile. A bolt action rifle just eliminates variables that you would otherwise have to compensate for, or try to compensate for.\n\nSemi autos have some mechanism for auto loading the cartridge. It could be blowback, recoil, or gas operated, or manual (Gatling gun). Every one of these processes introduce different variables. More variables=less accuracy. ", "Because semi autos typically use a gas system to cycle another round into the chamber. The gas system is fixed to the barrel and causes movement of the barrel between shots, thereby causing inconsistency and inaccuracy in groupings (multiple shots at the same place). It isn't that a sniper wants a bolt action; it's more that they want a free floating barrel. This means that the barrel attaches only to the receiver (bit where all the bullet/bolt stuff happens). Free floating barrels are almost exclusively bolt action. This allows the barrel to return to as close to the same point after each shot with far greater consistency, allowing a sniper/marksman to put all his rounds to the same spot as often as possible.\n\nI'll note that some snipers do use semi auto rifles for a number of reasons (availability of ammo, the need to engage multiple targets rapidly, attachment options, etc). Actually iirc Carlos Hathcock made a long range kill of 2286m with a Browning M2 machine gun, which is fully automatic." ] }

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[ [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [ "https://www.barrett.net/firearms/model82a1", "https://en.wikipedia.org/wiki/SR-25" ], [ "https://www.youtube.com/watch?v=NtwhZj1_TlI", "https://youtu.be/QKa4OQBejKQ", "https://youtu.be/DX73uXs3xGU", "https://en.wikipedia.org/wiki/EXACTO", "http://thearmsguide.com/611/how-guns-work-striker-fired-pistols/" ], [], [], [], [], [], [], [ "https://en.wikipedia.org/wiki/Mk_12_Special_Purpose_Rifle", "https://en.wikipedia.org/wiki/Mk_14_Enhanced_Battle_Rifle", "https://en.wikipedia.org/wiki/M24_Sniper_Weapon_System" ], [], [], [ "https://www.youtube.com/watch?v=L_E_GJayano" ], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [ "https://jga.anschuetz-sport.com/index.php5?produktID=91&amp;menu=106&amp;sprache=1&amp;produktShow=detail" ], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [] ]

{ "a_id": [ "cugr9lc" ], "score": [ 2 ], "text": [ "Well, Confession is having your sins absolved, that is, return to a state of grace and avoid a path leading to damnation. A reconciliation, if you will. But there is still a need to make up for the consequences of sin, most notably the offense the penitent has caused to God. Now ordinarily this is achieved after the death of the penitent in Purgatory. But this can also be done by doing pious works or actions, which are indulgenced, and commute this reparation, in whole or in part. That is an indulgence.\n\n" ] }

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{ "a_id": [ "cqbrj2u", "cqbtoat" ], "score": [ 7, 2 ], "text": [ "We actually are not quite sure what fully causes the feeling of being tired or lethargic. One simple explanation that has the most proof appears to be that a chemical called adenosine builds up in our brain throughout many of our daily activities. Adenosine is the byproduct of many metabolic functions (such as ATP being broken down for energy at a cellular level) in the body, and when enough of it builds up in our brain, we get tired. Similarly, when we drink things that are caffeinated, it blocks adenosine from binding to receptors in our brain and keeps us awake. This is a very simple explanation, you could find further reading here:\n\n_URL_0_\n\n_URL_1_\n", "Not an anaswer, but just a question to clarify your question. Is there a particular time of day you feel tired and lethargic, e.g. after eating lunch, or a high-sugar snack, then not moving for a long period of time?" ] }

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[ [ "http://health.howstuffworks.com/wellness/drugs-alcohol/caffeine-awake.htm", "http://www.news-medical.net/health/What-is-Adenosine.aspx" ], [] ]

{ "a_id": [ "dif0ewi", "dif98zh", "difax5k" ], "score": [ 34, 2, 11 ], "text": [ "Most songs nowadays are composed using layers on a track. So all it really takes is removing the layer. It's trickier with older songs that didn't use this production method.", "One of my best friends runs a company that sells music to adverts and TV shows and the like. Most bands have an instrumental version of all songs they've recorded, so they can licence them to ads etc. ", "Little late to the party but I figured I'd add my two cents and hope you see it. \n\nI'm an audio engineer in a studio in Pittsburgh, and before that I worked in a large studio in Chicago called CRC. CRC is one of the biggest independent studios in the country and we did both music and post-production (video games, movies, tv shows, etc.) \n\nWhat other people are saying about layers is correct. You have multiple tracks in a single session/song. When the final mix is done, all those tracks are combined into a two channel mix and very often a summed mono mix so that normal stereos can play the track. \n\nWhile I was at CRC, it was very common for us to finish the final mix, and then do multiple variant mixes that we would then give to the artist. For example, we would print the final mix, then we would turn the vocals up a pinch and print a VOX Up mix, then turn them down and do a VOX Down mix, then mute all the instruments and do an acapella mix and then mute all the vocals and do an instrumental mix. We would give all these mixes to the artist or label and then when someone wanted to use the instrumental track for something like a movie trailer, the artist already had an instrumental mix that they could send right away. \n\nOnce a mix is printed it's damn near impossible to remove just the vocals and not affect anything else. I say damn near because there could possibly be a program out there that could do it, but I don't know of any and I'm not sure how it would be possible. Like you mentioned previously, if you isolate the frequencies of the vocals you're also going to isolate and remove any instrument that falls in that frequency range. \n\nHope this helps! " ] }

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{ "a_id": [ "dig3okt" ], "score": [ 19 ], "text": [ "There are a couple of narratives that attempt to explain this. The traditional narrative proposed by later Muslim scholars is that when the Abbasid dynasty usurped power from the Umayyads in 750 CE, this represented a shift in power from Arabs to the numerically and culturally much stronger Persians. From this, we have two dovetailing explanations of the interest in science: 1) they wished to recover the former glory of the Persian Empire, and 2) in order to gain political legitimacy, they essentially drew together all the various scholarly traditions from their polyglot empire, had everything translated into Arabic and established schools of translation and development, where works of classical Greek, Babylonian, Egyptian and Persian science and philosophy were built upon by succeeding generations of scholars. A proper ruler is one who has a court of scholars, became the principle, so when the caliphate began to fragment, the petty kings all drew to themselves their own scholars in order to seem more kingly. Scholarship itself was something of a meritocracy (for men): even a village lad, if sufficiently able, could be essentially passed up a food chain of scholars and eventually find a position at a court. These trends reinforced each other, plus scholarship had a lot of practical value and applications. The quest for knowledge was supported by some cherry-picked quotations from the Qur'an and Hadith in order to make it appear that a proper *Muslim* ruler had an obligation to support scholarship. This period is held to have ended (again, this is a traditional narrative) around the year 1100 as the notion that a proper Muslim eschewed the natural world in favor of prayer and meditation began to take hold. \n\nBut there are some real problems with this traditional narrative. For one thing, the idea that scientific development came to a halt is provably false: it continued, albeit at not quite such an increasing pace, well into the 16th century CE and only then really began to stagnate. For another (and forgive me, I'm on holiday and don't have sources with me, but the scholar whose work I'm badly summarizing here is George Saliba), the way in which the \"translation movement\" sprang into print in full bloom is unpersuasive: for the initial generation of works in Arabic to have been so sophisticated implies at least another generation of unseen scholars beforehand, and therefore the explanation that the early Abbasids were the driving force is problematic. There's some real driving force(s) for scholarship for its own sake during Umayyad times, one(s) we don't know much about because we don't know nearly as much about the Umayyads as we'd like." ] }

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{ "a_id": [ "c76xee9", "c76ywmz", "c76z9wv", "c770qpz" ], "score": [ 5, 4, 10, 2 ], "text": [ "Andrew Johnson (president after Lincoln) was born in N. Carolina and grew up in Tennessee. \n\n_URL_0_", "John Hennington, the Postmaster General of the CSA was able to make it back as a Congressman and eventually Senator from Texas, but a quick wiki search shows that most of the Confederate cabinet went into private work.", "General James Longstreet joined the Republican Party after the war and was appointed as the head of Louisiana's Reconstruction-era militia. \n\nHe was despised by many fellow Southerners, despite heroic service in the Confederate cause, especially after the 1874 Battle of Liberty Place - Longstreet, commanding black troops, ordered them to open fire on a mob of white Southerners who were attempting to remove the state's elected government by force. \n\nLongstreet served as a federal railroad commissioner and an ambassador in his later years. He was hounded until his death by Southern critics who (ironically from a certain point of view) thought he was a traitor, and who tried to rewrite history to dismiss his sterling military record.\n\n_URL_0_", "Joseph Wheeler (_URL_0_) was a Confederate general who was later given a command in the 1898 Spanish-American war; between the wars he served as a congressman representing Alabama. Allegedly, in the heat of battle in Cuba, he was heard to shout \"Let's go boys! We've got the damn Yankees on the run!\" momentarily confusing his wars. Further, I remember learning in American History class that the Spanish-American war was an important event in the re-integration of the American armed forces following the Civil War as old enemies fought side-by-side." ] }

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[ [ "http://en.wikipedia.org/wiki/Andrew_Johnson" ], [], [ "http://en.wikipedia.org/wiki/James_Longstreet#Postbellum" ], [ "http://en.wikipedia.org/wiki/Joseph_Wheeler" ] ]

{ "a_id": [ "c397bs9", "c397c9e", "c3997s5", "c397bs9", "c397c9e", "c3997s5" ], "score": [ 5, 4, 4, 5, 4, 4 ], "text": [ "No. It says that two identical fermions (like electrons) can't occupy the same energy state. For example, two spin-up electrons can't both be in the 1s orbital (the closest to the nucleus). However, in two adjacent atoms, the electrons in the 1s orbital will both have the same energy, but still not be degenerate because it's a different atom.", "I think you are correct. The Pauli exclusion principle isn't even really about energies, it's about quantum states. Two electrons may not occupy the same quantum state, but this isn't the same thing as not having the same energy.\n\nI don't know what Cox actually said, but perhaps he was making some big simplifications to cram things into popular science. You could certainly make vague statements about energy and the universe using the Pauli exclusion principle, which might sound something like what you recall. For instance, we could certainly say that no two electrons *in the universe* can have the same quantum state, but this sounds more impressive than it really is because most of them are in different places which automatically makes their states different.", "What the Pauli exclusion principle really says is this: the wavefunction describing all of the electrons in the universe must be completely anti-symmetric under exchange of any two electrons in the universe. Luckily, most electrons are pretty non-relativistic and therefore pretty well localized in space. The as iorgfeflkd suggested (but was not sufficiently explicit), you can *effectively* treat systems one at a time because the electrons are well localized.\n\nHowever, it's still true that (according to QFT) the entire wavefunction everywhere in the universe is affected when you twiddle an electron here (but still in a causal fashion).", "No. It says that two identical fermions (like electrons) can't occupy the same energy state. For example, two spin-up electrons can't both be in the 1s orbital (the closest to the nucleus). However, in two adjacent atoms, the electrons in the 1s orbital will both have the same energy, but still not be degenerate because it's a different atom.", "I think you are correct. The Pauli exclusion principle isn't even really about energies, it's about quantum states. Two electrons may not occupy the same quantum state, but this isn't the same thing as not having the same energy.\n\nI don't know what Cox actually said, but perhaps he was making some big simplifications to cram things into popular science. You could certainly make vague statements about energy and the universe using the Pauli exclusion principle, which might sound something like what you recall. For instance, we could certainly say that no two electrons *in the universe* can have the same quantum state, but this sounds more impressive than it really is because most of them are in different places which automatically makes their states different.", "What the Pauli exclusion principle really says is this: the wavefunction describing all of the electrons in the universe must be completely anti-symmetric under exchange of any two electrons in the universe. Luckily, most electrons are pretty non-relativistic and therefore pretty well localized in space. The as iorgfeflkd suggested (but was not sufficiently explicit), you can *effectively* treat systems one at a time because the electrons are well localized.\n\nHowever, it's still true that (according to QFT) the entire wavefunction everywhere in the universe is affected when you twiddle an electron here (but still in a causal fashion)." ] }

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{ "a_id": [ "c2os06o", "c2ousk4", "c2os06o", "c2ousk4" ], "score": [ 5, 3, 5, 3 ], "text": [ "I can't give you a run down of all the groups but I can give a general description of the Mafia.\n\nPicture Sicily as a schoolyard playground. Everyone's playing and having a good time, but some kids start bulling other kids. When the teacher is told, they don't do anything and mostly just look the other way. A few kids get together a decided that it's up to them to stop the bullies and make sure that others don't show up. These kids start the Mafia to get ride of the bullies that the teachers won't touch and make sure that more don't show up later. As time goes on the Mafia needs to gather some money because a bully beats up some of the Mafia members. They turn to the other kids they have been protecting and tell them since they are the ones protecting them, that they need to pay for the band-aids. This turns into regular collections for the next time a bully shows up. When some kids complain that there haven't been any bullies for a long time, and refuse to pay for band-aids that aren't being bought(since there are no need for the band -aids the Mafia has been buying soda's for it's members instead). That makes the Mafia angry and they go and bully these kids into paying for the protection. That creates the protection rackets that were the base of the Mafia, eventually they add other criminal enterprises most which began as services like smuggling restricted items. As time went on the Mafia grows in size and eventually inspires other groups to do the same or have Mafia members start their own Mafia.\n\nHope that helps", " > all they got from Paulie was protection from other guys looking to rip them off. And that's what it's all about. That's what the FBI could never understand. That what Paulie and the organization [i.e. the Mafia] does is offer protection for people who can't go to the cops. That's it. That's all it is. They're like the police department for wiseguys.\n\n- GoodFellas.\n\nthis applies to pretty much any form of Mafia (Russian, Italian, Mexican, etc.) ", "I can't give you a run down of all the groups but I can give a general description of the Mafia.\n\nPicture Sicily as a schoolyard playground. Everyone's playing and having a good time, but some kids start bulling other kids. When the teacher is told, they don't do anything and mostly just look the other way. A few kids get together a decided that it's up to them to stop the bullies and make sure that others don't show up. These kids start the Mafia to get ride of the bullies that the teachers won't touch and make sure that more don't show up later. As time goes on the Mafia needs to gather some money because a bully beats up some of the Mafia members. They turn to the other kids they have been protecting and tell them since they are the ones protecting them, that they need to pay for the band-aids. This turns into regular collections for the next time a bully shows up. When some kids complain that there haven't been any bullies for a long time, and refuse to pay for band-aids that aren't being bought(since there are no need for the band -aids the Mafia has been buying soda's for it's members instead). That makes the Mafia angry and they go and bully these kids into paying for the protection. That creates the protection rackets that were the base of the Mafia, eventually they add other criminal enterprises most which began as services like smuggling restricted items. As time went on the Mafia grows in size and eventually inspires other groups to do the same or have Mafia members start their own Mafia.\n\nHope that helps", " > all they got from Paulie was protection from other guys looking to rip them off. And that's what it's all about. That's what the FBI could never understand. That what Paulie and the organization [i.e. the Mafia] does is offer protection for people who can't go to the cops. That's it. That's all it is. They're like the police department for wiseguys.\n\n- GoodFellas.\n\nthis applies to pretty much any form of Mafia (Russian, Italian, Mexican, etc.) " ] }

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{ "a_id": [ "c3ap081", "c3ap081" ], "score": [ 8, 8 ], "text": [ "Generally, modern homes have pipes that are small and water is often in demand.\n\nThis leads to water that is moved often and never really gets a chance to sit still in one place for too long. The pipes which are made of usually copper of plastic are in themselves terrible environments for many pathogens. The fact that tap water itself is quite clean leads to no real source of contamination.\n\nDrinking tap water is safe and if your houses plumbing is up to spec, you should be just fine.", "Generally, modern homes have pipes that are small and water is often in demand.\n\nThis leads to water that is moved often and never really gets a chance to sit still in one place for too long. The pipes which are made of usually copper of plastic are in themselves terrible environments for many pathogens. The fact that tap water itself is quite clean leads to no real source of contamination.\n\nDrinking tap water is safe and if your houses plumbing is up to spec, you should be just fine." ] }

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{ "a_id": [ "c2ik1qi", "c2ik1qi" ], "score": [ 2, 2 ], "text": [ "*“Glass, as well as some plastics, has a net negative charge on its surface, so a wrap that has an opposite charge is going to cling quite well to these surfaces,”* [SOURCE](_URL_0_)\n\nAnother site has a more chemical approach:\n\n*\"I found that most kitchen plastic wrap is made of low density polyethylene, also known as LDPE. This plastic makes a good barrier to water and air, but it does not stick to itself. To make it cling, they add another chemical, such as polyisobutylene or poly[ethylene-vinylacetate]. These chemicals do not mix totally with the LDPE. Instead, they act like the adhesive on tape, only not as sticky, and it only sticks to certain things.\"* [SOURCE\n](_URL_1_)\n\nHope this helps.", "*“Glass, as well as some plastics, has a net negative charge on its surface, so a wrap that has an opposite charge is going to cling quite well to these surfaces,”* [SOURCE](_URL_0_)\n\nAnother site has a more chemical approach:\n\n*\"I found that most kitchen plastic wrap is made of low density polyethylene, also known as LDPE. This plastic makes a good barrier to water and air, but it does not stick to itself. To make it cling, they add another chemical, such as polyisobutylene or poly[ethylene-vinylacetate]. These chemicals do not mix totally with the LDPE. Instead, they act like the adhesive on tape, only not as sticky, and it only sticks to certain things.\"* [SOURCE\n](_URL_1_)\n\nHope this helps." ] }

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[ "http://www.youtube.com/watch?v=tWxMuO1UfCY" ]

[ [ "http://www.chow.com/food-news/54464/how-does-plastic-wrap-cling/", "http://nicholasacademy.com/scienceexperiment269staticcling.html" ], [ "http://www.chow.com/food-news/54464/how-does-plastic-wrap-cling/", "http://nicholasacademy.com/scienceexperiment269staticcling.html" ] ]

{ "a_id": [ "dkp13x1", "dkq7i6x" ], "score": [ 2, 2 ], "text": [ "I'm a med student.\n\nActually There isn't any specific direction. If i assume complete rest is a \"deep sleep\" . It's gonna be a REM or Non-REM sleep stages which could be any random direction and our eyes are continously moving fast (In REM) and slow (non-REM)", "It depends how you define complete rest.\n\nIn case of sleep I would call complete rest the REM-sleep. And REM stands for \"rapid eye movement\". So basically in no direction since your eyes are moving fast under closed eyelids. When not in REM-sleep your eyes will most likely centric or being slightly downwards." ] }

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{ "a_id": [ "d196cny" ], "score": [ 6 ], "text": [ "A reply to /u/ManicMarine \n\nUgggggghhhhh ... this is such a good question and such a complex topic at the same time ...... ! :D\n\nFirst we must set the scene properly in terms of how the \"military fiscal state\" was [evolving in that era](_URL_0_). He had set up a \"state within state\" system whereby he controlled not only the army and its logistics, but also the collection of \"revenue\" through taxation and other means, to supply his army. In this sense, he was a highly innovative commander. He had come at just the right time, too, as the Imperials needed help in 1625 as Tilly's Catholic League forces were overstretched and Spain's army of Spinola was tied up in the Low Countries, and there were rumors of new movements by Bethlen Gabor from Transylvania. So Ferdinand made Wallenstein \"chief of all our troops already serving, whether in HRE or Netherlands,\" and to \"create a field army, whether from existing units or new regiments, to be 24,000 men in all.\" Now, Ferdinand did not nearly have money to pay for all this, so as the campaign progressed, Wallenstein was rewarded with confiscated estates from HRE princes. At this point, Wallenstein largely followed strategic direction from Ferdinand as he campaigned northwards against Denmark and into the Baltics. As time progressed, his army ballooned in size to around 150,000 troops as it had to not only challenge its opponents, it also had to occupy territories it had conquered. He argued that it was the only way to keep Saxony and Bavaria's princes loyal, not to mention rebellious peasants at various towns and villages. Thus, in order to maintain his army Wallenstein started to impose a fixed taxation system, paid every week, called the \"contribution system\". At the same time he started to sell commission even to criminals and foreigners in order to raise revenue. This led to colonels and captains profiteering and abusing the populace. \n\nThe three aspects above (confiscating estates and giving them to Wallenstein, taxation, selling of officership) started to be an issue with HRE Electors. In 1627, while they met to discuss the Edict of Restitution, they complained bitterly. As there was still war, Ferdinand ignored them. However, by 1630 the complaints could not be ignored anymore. Both the Electors and the Pope complained that Wallenstein's very presence was the only thing in the way of peace. \n\nWhen Ferdinand finally dismissed Wallenstein, it was said that Wallenstein \"seems to have been almost relieved\" as he knew his army was unwieldy and beyond maintenance. He retired to his estates in Bohemia and his erstwhile chief financier Hans de Witte, who had staked his family's fortune on this army, committed suicide. Unsurprisingly, troops of the army became restless and there was mutiny and violence. \n\nOf course, things went badly for Ferdinand as Sweden entered the war, and Tilly was killed in battle. So by 1632, Wallenstein was back as commander of the Imperial forces, and needed only three months to raise a major army. It is said that he took command only reluctantly, past his prime at age 49. Successes immediately followed in Bohemia, Silesia, and Saxony. He made one tactical mistake in Lutzen, but survived albeit with significant losses. Just as before, it was a major issue where to quarter the army. By this point it was preferred to place them in enemy territory such that friendly territory isn't subjected to taxation and violence. In winter 1633-34, Wallenstein insisted to quarter his troops on Habsburg lands in Bohemia for security reasons; following Lutzen, it was really unclear what had happened to the opposing armies and not much was known about their locations. So in a way, he was justified in seeking friendly territory for quartering his troops. This, after a fairly slow campaigning season that appeared to achieve little for Ferdinand. His other excuse was that he had tried to exploit political disagreement between Sweden and Saxony, arranging a cease fire and opening a negotiation. These may have seemed excessive, but not outside the powers which were vested in him at the time. However, at the same time, the campaign of Spain's Cardinal-Infante had just started, except that it was kept under separate command instead of placed under Wallenstein. The sum of all this was the bruising of Wallenstein's relationship with the courtiers in Vienna. Wallenstein had criticized the Edict of Restitution and the HRE's continuing support of Spanish campaigns up the Rhineland to the Low Countries; and he was said to claim he alone would negotiate peace with the Protestants, at least the Lutherans. Now he had his army in Bohemia, his personal duchy, and the sum of all this was the perception of threat. \n\nWhat became remarkable was his extraction of oath of *personal* loyalty from his Colonels. This brought the relationship truly sour, the Ferdinand declared him rebel. But even further than that, the winter spent in Bohemia was also a time of trouble for his officers. There was a so-called \"Prague blood tribunal\" in which dozens of officers were executed for cowardice. So to his officers, he appeared to be looking for a scapegoat for the seemingly fruitless campaigns of 1633. His co-commander Piccolomini had personally requested clemency for an officer, yet this was declined. Even worse, to states of the Catholic League, Wallenstein was seen as an opportunist as he both sold officerships to raise money, and yet offered larger salaries and benefits to poach officers from allied armies of the League. As both his relationships with the emperor soured and so did his relationship with theoretical allies, and so did the loyalty of his men; this offered the perfect opportunity that led to his murder. \n\nSo back to the question: was he a traitor? Circumstances changed around him, both due to him and due to the emperor, the elector princes, and Spanish interest in the Spanish Road and the Low Countries. I think he was caught in the struggle of early-modern europe, and he ended up with an army that nobody could tolerate. In the end it was clear he was likely to have been disloyal, but up to the summer 1633 he was loyal to the emperor. \n\nA further question could be asked, was far, how wide, and how long had he sustained what seemed to be limitless ambition, which some say was to become king or emperor himself. This is an enduring myth of Wallenstein, helped with the fact that he rose very, very highly. But some modern historians have compared his trajectory with those of his peer and Mortimer -- author of several critical books on the 30YW -- agree with others that the choices he made was not out of the ordinary. Mortimer further contended that Wallenstein was a very smart man in his responding to changing circumstances, and indeed the 30YW was a very interesting time. Even going back to his first proposal to raise an army, it should be kept in mind that he was Prince of Friedland, thus he had every reason to back the emperor in defending Bohemian lands. More strongly, some authors have contended that his failure was partly due to his lack of ambition. That if he had done more to control the politics of the court, then he will have been able to leverage the emperor's patronage. \n\nTL;DR Complicated subject, you can judge for yourself. " ] }

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[ [ "https://www.reddit.com/r/AskHistorians/comments/49r3ln/did_arms_dealing_as_private_enterprise_exist_in/d0unxha" ] ]

{ "a_id": [ "c6bjtd0", "c6bk3v7", "c6bk592", "c6bo1t4" ], "score": [ 5, 2, 3, 2 ], "text": [ "Look at a bunch of adverts for cars that are the price you can afford. Keep the price on the cheap side. You are only learning about cars at this stage. Pick out a few that you like. It doesn't matter why you like them for now. Make a note of the milage and age of the cars and what condition they are in, e.g. is the paint work faded or rusty, how \"good\" does it look. \n \nArmed with this information go to a car dealership and ask to look at cars of the type you liked from the adverts or look in the paper/Internet for cars for sale of that type. \n \nIf you find a car of the type you like that is cheaper than your research and has the same milage and looks to be in the same or better condition you may have found your new ride. \n \nThings to watch out for \n \n* Cars with low milage yet the pedals are worn from use\n* Cars with low milage yet the seat belt looks old/worn\n* Cars with signs of repainting. Different colour inside doors, under bonnet, overspray on exaust pipe, etc\n* Cars missing trim, logos, make/model on boot. Boot was replaced after a crash.\n* Cars with missing documentation\n \nIf you can afford it try to do a check online or otherwise on the car to make sure no outstanding finance is owed by the previous owner. If you buy a car form a guy who owes money on it it might be repossesed even though you paid full price for it. \n \nIn general buy an old, cheap but hopefully sound car and use it to learn about cars and driving. Your next purchase will be much more informed. ", "Shop around and use _URL_0_ to look up reviews on the cars you are looking at.", "Are we talking about a new car? Visit each reputed maker's website: Honda, Toyota, Nissan, Ford, Hyundai etc. All of them have prices and specs displayed. \n\nMake a spreadsheet listing each vehicles price, pros and cons.\n\nOnce you've narrowed it down to a handful of cars, visit _URL_1_, _URL_0_, _URL_2_ and _URL_3_ and make note of what the average market value of the car is (this is what people are paying for a new car in your area). This does not include taxes and other fees (comes to about $1500-$2000 for a new compact sedan below $20,000). \n\nGo drive each car and get a good feel for it. Take your time and don't let them rush you through it. \n\nNow find out the invoice price of each car (this is what the dealership paid the maker for the car). You should ideally pay as close to the invoice price as possible. \n\nSome dealerships/manufacturers will offer you incentives if you finance through them. Call and ask. Talk to a few banks and see what kind of interest rate you can get. A co-signer with outstanding credit will knock down your interest rate substantially.\n\nFind all the dealerships for your choice of cars and get quotes over email. Now visit them in person when you are ready to buy and offer to pay invoice price. Do not budge. Let the salesman tire out from walking to his manager's office. If they appear hostile or disrespectful, walk away. Google if your state has a maximum documentation fees and don't pay a penny over that. You should pay the tax, doc fee, tag and title fee over the car's price. Refuse to pay any prep-fee or extras like paint guards or tinted windows. You can always get these later.\n\nIf you buy during off-season and have great negotiating skills you could probably get away paying less than invoice price. Keep an eye out for when 2013 models are announced because it means the 2012 models will be that much cheaper in months to come.\n\nAlso take a look at certified pre-owned vehicles. Sometimes you will catch a good deal. Don't bother with cars that have been driven over 15000 miles a year.\n\nDon't trade in your current car. Sell it yourself on Craigslist. Get an inspection report from a certified mechanic. Makes the process easier.\n\nThe bottom line is: Don't rush the process. Remember that you always have the upper hand. Be firm without being disrespectful. ", "I personally wouldn't buy a car from dealer. If you do and arnt comfortable with confrontation then have a friend be there to help negotiate the deal. The ONE thing I would recommend is always walk away after the test drive for an hour or two (have lunch etc) and think about it. The car will be there if you decide you like it. Also go to a bank and secure prior financing. This can help bargin a deal. You don't and shouldnt give them anything to look at your credit before you decide for sure you are going to buy the car. For two reasons. One multiple credit look ups lower your cradit score, and two if you have poor credit it allows them to leverage that against the price. \nHope this helps.\n" ] }

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[ [], [ "Kbb.com" ], [ "kbb.com", "truecar.com", "edmunds.com", "nada.com" ], [] ]

{ "a_id": [ "cguurrx" ], "score": [ 5 ], "text": [ "Business as usual in what way? Because Europe really didn't just keep trucking along. The 30 Years War more or less reworked the political landscape of Europe and the way diplomacy was run. You mention the Swedes invading Poland and I think that's a great example of how things changed. At the outset of the war, one of the biggest worries of the Hapsburgs was the army of Denmark (which turned out to be a paper tiger). The Swedish army wasn't even considered. When the Swedes intervened their army was discovered to be potent and capable, but it was \"thin.\" Sweden's army was maintained by conscription in a very thinly populated land. That Sweden was able to invade Poland after the Thirty Years War is related to its relatively untouched landscape and the fact that everyone around Sweden had been knocked down a peg. After the war, who around Sweden was going to be able to stop them, when you consider that they had an experienced army and were probably the most densely populated single polity in their region?\n\nOther things changed around the era, too, which reflects the general upheaval at the end of the Thirty Years War. The Roundheads in the United Kingdom finally put the finishing touches on King Charles' Cavaliers, leading to years of Cromwell's leadership and the execution of Charles I. The Fronde began in France, which crippled the French kingdom for five years and eventually led to Louis XIV refining absolutism to his nobility's detriment. Spain was financially exhausted and had no choice but to let Portugal go when it revolted. The individual German princelings and kings were allowed to conduct their own foreign policy (which would fatally fracture the Holy Roman Empire as a united entity).\n\nIt's tempting to describe the German heartland as a desert, but in some ways that's what it was. The power centers in Europe moved towards France, Vienna, and-- a little late-- London. Europe didn't just keep going: it was dramatically transformed. What you're really seeing is that previously \"second-rate\" powers taking advantage of the situation to try to transform themselves into first-rate powers." ] }

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{ "a_id": [ "dll689y" ], "score": [ 3 ], "text": [ "People with low incomes also have the fewest options in what products they can buy. That makes them a captive consumer base and means that companies can charge them more than more affluent people with more choice in products and services.\n\nPoor people are also much less likely to have received a good financial education and are thus easier to deceive with bad deals and fraudulent practices." ] }

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{ "a_id": [ "ctsz1te", "ctt34gi" ], "score": [ 2, 2 ], "text": [ "They didn't used to be. Toothpaste and dental care took off though and eventually white teeth became preferable - it equals health and indicates that you take good care of your body and self.", "Because teeth yellow with age, and so yellow teeth suggests being less youthful. And teeth yellow when not cleaned thoroughly, suggesting worse dental care and dental health." ] }

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{ "a_id": [ "eroccdg", "erpc9ux", "erq1e2v" ], "score": [ 18, 4, 6 ], "text": [ "every molecule is not at that temperature at the same time. It is a gradient from the energy source to the furthest point. \n\nWhen you put a simmering pot on the stove. The heat is transferred from the fire to the pot body which conducts heat really well.the water immediately touching the walls of the pot will get the heat first and then it diffuses inwards. \n\nSo if the temperature at the body of the pot is say 250, the. The water immediately in contact with it will get to 230 creating small bubbles wherever the water touch the pot and these will take the energy and leave the pot, so the water in the center is cooler than 212 and thus it won’t boil. \n\nNow crank up the heat and the pot body temp rises to let’s say 400-500. Now the heat is transferred so much faster and the whole body of water is above 212 and rustling to form gas bubbles and escape, this is when you get a roaring boil", "When adding heat, the edges and base of the container heat up first due to being in more direct contact with the flame and this the water closer to the edges heats up and boils first followed by the rest of the water in the container heating up and boiling", "The other answers aren't entirely correct, especially in the usual case where the simmering pot of liquid is well-mixed. The real answer is that the edges of the pot provide [nucleation sites](_URL_0_).\n\nFirst of all, remember that changing phase requires a change in energy (enthalpy of vaporization) significantly larger than the amount needed to raise the temperature while the substance remains in the same phase (specific heat capacity). Because of this, even if the liquid is heated somewhat unevenly, the molecules that reach boiling temperature first will tend to transfer additional energy they receive to the rest of the liquid via conduction or move away from the heat source via convection, rather than boiling immediately. In other words, for a household stovetop (as opposed to some kind of powerful industrial burner), the entire pot of water is likely to be at a nearly-uniform 100C before the first molecules boil.\n\nSecond, an individual molecule can't gain enthalpy of vaporization gradually -- it has to gain it all at once, in a stochastic sort of way (in other words, hand-wavey quantum mechanics that I don't understand and thus can't explain). Moreover, because of surface tension, the bubble of gas formed by a group of adjacent boiling molecules tends to collapse back to liquid, and does so with a probability inversely proportional to the size of the bubble.\n\nThird, that surface tension/tendency to collapse is related to the shape of the bubble: one suspended in the middle of the liquid is being squeezed from all sides due to cohesion, whereas one against a dissimilar-material surface is only being squeezed from the sides other than that surface. Therefore, the activation energy necessary to create a bubble of critical radius adjacent to a surface (heterogeneous nucleation) is lower than the energy necessary to create one in the middle of the liquid (homogeneous nucleation), so the former happens a lot more often than the latter and the pot boils along the edges." ] }

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[ [], [], [ "https://en.m.wikipedia.org/wiki/Nucleation" ] ]

{ "a_id": [ "di5kk5t" ], "score": [ 15 ], "text": [ "\nYour front brain simulates consequences and chooses the best action to take. When you're emotional, this usually means stopping you from doing something like punting your co workers. Sometimes one or multiple emotions become really strong and it takes lots of effort to stop you from acting on them. Effort makes your brain tired, and either it becomes worse at modulating behavior OR the emotions become too strong for the front brain to hold back. Then you have an emotional outburst where the front brain is kinda offline. " ] }

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{ "a_id": [ "dgebp5o" ], "score": [ 15 ], "text": [ "In essence, indifference.\n\nThe general sentiment was that France had abandoned New-France in favor of the French West Indies, that were much more profitable than the rather onerous North American colony. This is also a sentiment that can be found in the lesser rates of volunteerism in WWI, although at that point, it's a lot more complicated.\n\nConcerning the overture made by the American congress to french Canadian, it was more in the hope of making sure they wouldn't attack, as the French-Indian raids were still very much in the minds of the revolutionaries. To simplify, the Americans were scared of the french colonists descending by the Champlain River to greatly undermine their effort.\n\nThe other reason is basically because the British, seeing shit was about to hit the fan passed the Quebec Act which softened, if not completely reversed, a lot of the anti-catholic/ anti-french policies the British had put in place after the Conquest, making it considerably less interesting to rebel against the authorities that basically almost restored the way of life before the Conquest.\n\nEDIT :\n\nAfter going back a little bit in some reading, the American Congress did send letters to French Canadians as early as 1774, The letter title is : Lettre adressée aux Habitans de la province de Quebec, Ci-devant le Canada\".\nIt's in French, so you can definitely know it was addressed to the french speaking elite. That very same elite that benefited the most from the Quebec Act...\n\n" ] }

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{ "a_id": [ "dunz7ga" ], "score": [ 2 ], "text": [ "The primary book for the reign of Nebuchadnezzar II is in French (Arnaud's *Nabuchodonosor II, roi de Babylone*). DJ Wiseman's *Nebuchadrezzar and Babylon* is useful, as is Ronald Sack's *Images of Nebuchadnezzar: The Emergence of a Legend*. \n\nVanderhooft's *The Neo-Babylonian Empire and Babylon in the Latter Prophets* and Cogan's *The Raging Torrent: Historical Inscriptions from Assyria and Babylonia Relating to Ancient Israel* are worth a look if you're interested in the interactions between the Neo-Babylonian empire and Judah. \n\nThe Babylonian chronicles are our main source of knowledge, which have been edited in Grayson's *Assyrian and Babylonian Chronicles*. The three volumes of *The Context of Scripture* and *The Ancient Near East: Historical Sources in Translation* edited by Mark Chavalas also contain useful translations. There is an [ORACC project](_URL_0_) editing Neo-Babylonian texts, but unfortunately they haven't gotten around to the reign of Nebuchadnezzar II yet.\n\n\n\n" ] }

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[ [ "http://oracc.museum.upenn.edu/ribo/babylon7/index.html" ] ]

{ "a_id": [ "ccy5t7w" ], "score": [ 3 ], "text": [ "I'm sure you know the three most important words in real estate: Location, location, and location. Nice areas have proximity to some desireable feature--be it parks, the waterfront, downtown, public transit, nice views, historical areas, nice looking bridges, any or all of these things. These desirable features drive up property values, which has the effect of inviting in the rich people and their amenities and pricing out the riff raff. Meanwhile, not nice features such as abandoned factories, power plants, highways, ugly bridges don't do anything good for property values. They stagnate or drop, and these parts of town become the \"bad part of town.\"" ] }

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{ "a_id": [ "c4dp45i", "c4dp50l", "c4dpg5o", "c4dphwf", "c4dpryb", "c4dqhsn", "c4dqoar", "c4drysw", "c4dsc0h", "c4dtlm6", "c4dx97u" ], "score": [ 12, 416, 21, 7, 76, 4, 4, 8, 7, 3, 2 ], "text": [ "Keep in mind that unless the earth also stop revolving around the sun (not possible), or the earth keeps rotating at a very slight rate similar to the moon (to have the same side facing the sun everytime) , the dark and bright side would change every six months. Basically a day would last for the entire year. I suppose you would have regular conditions with arctic-like time spans for seasons. And you would have to factor the resulting climatic disturbances in.", "Planets that \"have stopped rotating\" are known as being tidally locked. Earth's moon is tidally locked to the Earth, and so only one side faces us at all times. If a planet is close enough to its parent star it will become tidally locked. Observation of exoplanets determined to be tidally locked indicated extreme winds between day and night sides. \n\nHD 189733 b is a roughly Jupiter sized exoplanet which exhibits this phenomenon. A temperature range of 973 ± 33 K to 1,212 ± 11 K was discovered, indicating that the absorbed energy from the parent star is distributed fairly evenly through the planet's atmosphere. Assuming the planet is tidally locked, this suggests that powerful easterly winds moving at more than 9,600 kilometers per hour are responsible for redistributing the heat.\n\nIf something similar were to happen on Earth, we would all die very quickly. All crops and plants would quickly succumb to temperature variations of hundred of degrees Kelvin, the winds would rip out the largest trees. The entire ecosystem would most likely be destroyed. Significant quantities of water would boil into the atmosphere. If the heated atmosphere from the day side were incapable of keeping the night side warmed, theoretically the boiled off oceans could be transported to the night side where the water would be deposited and frozen.\n\nedit: We wouldn't *all* die, the crew of the ISS would be quite comfortable until their return to Earth.", "Would there be a sweet spot on the edges where the cold and hot meet? And how big would that sweet spot be? Could people live there?", "Given the assumption that this would be catastrophic to life on Earth (as per some of the top comments), maybe an alternative question would be, \"how would Earth be different today if it had started out tidally locked?\" ", "Googling revealed this reference: [Simulations of the Atmospheres of Synchronously Rotating Terrestrial Planets Orbiting M Dwarfs: Conditions for Atmospheric Collapse and the Implications for Habitability] (_URL_0_) (warning PDF download)\n\n\nTheir modeling seems to suggest that for a Earth-like planet the day-side temperatures would reach 330 K (or 135 F), while the dark-side would be just below 270 K (25 F, just below freezing) - at a slightly higher pressure. This being due to the atmophere being a good conductor of heat from the day side to the night.\n\nHowever I'm not an expert on this sort of thing and would like to hear from someone with more relevant experience.\n\n", "Something just occured to me...\n\nOnce Humanity got it's act together we could potentially put large orbital mirrors up to deflect some of the sunlight to the nightside. It would still screw up cicadian rythms but it would keep the planet habitable.\n\nIt's a Megastructure sure but if the whole race (or what was left of it) got behind it I think we have the technology to do it.", "Just another question, sorry if I'm stealing your question. But if the earth were to stop would there be severe damages caused by the sudden stop? I think the earth is spinning at something like 1xx, xxx km/h or something like that so wouldnt the force cause buildings and ect. to fall or whatever? ", "[If the Earth stood still...](_URL_0_)", "I disagree with the current top poster that claims we'd all die off. If this happened gradually over a period of 100 years or so, I think we could react and survive.\n\nMassive sturdy greenhouses could be built to protect plants from excessive winds and regulate temperature.\n\nWhere would the energy for this come from? Well alternative technologies would become MORE feasible due to the strong temperature differential. There would be strong winds at the border between light and dark which could be captured via a global network of wind turbines.\n\nI could also envision massive hydro-turbines using the temperature differential to generate energy from heating/cooling bodies of water using the ambient temperature.\n\nWe'd have to drastically change how we lived for sure, but we could survive it and possibly get a significant increase in the usable energy.", "If the earth became locked, would we be able to build enough rockets to get it turning again?", "All these posts and questions about buildings crashing and water tsunami waves are silly, even assuming instant deceleration.\nOne must make very precise constraints on what is \"Earth\". Aren't the buildings part of earth? the atmosphere? the ocean? the crust? the mantle? the core? Us? \nI would say all of it. Why assume some mass would stop rotating and some mass would not? it's SILLY. That wouldn't be ask science, it would be ask Hollywood (Michael Bay)" ] }

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[ [], [], [], [], [ "http://www.google.com/url?sa=t&amp;rct=j&amp;q=&amp;esrc=s&amp;source=web&amp;cd=1&amp;ved=0CCUQFjAA&amp;url=http%3A%2F%2Fcrack.seismo.unr.edu%2Fftp%2Fpub%2Fgillett%2Fjoshi.pdf&amp;ei=2MmOT_jsB-250QGyyPnNDw&amp;usg=AFQjCNFFzoyfY8rhHmz0MZWdIJ3oe3Yt5A" ], [], [], [ "http://www.esri.com/news/arcuser/0610/nospin.html" ], [], [], [] ]

{ "a_id": [ "egtq8hr" ], "score": [ 4 ], "text": [ "I have insufficient knowledge of Chinese history and the armies of Antiquity to answer the question from those specific angles, but where it concerns the recruitment and mobilization of the common man in Europe in the Middle Ages, the physical condition was definitely of little concern.\n\nI've written about the [approximate of the levy system in parts of the Low Countries](_URL_0_), the *heervaart*, before (which in a lot of aspects is comparable to the levy in other European domains, exceptions notwithstanding), but suffice it to say in this context that the military power of commoners from rural areas (farmers and/or peasants depending on the social-economic status) was lackluster, especially in comparison to the mobilized citizenry who not only often had a degree of military training as well as organization through the guilds, but also were financially in a better position to obtain armament, if at all necessary, as cities were in the habit of arming their own citizenry in times of external threats. Whether these citizens were also physically in a better state as some of their rural counterparts is difficult to conclude with certainty, but is doubtful. On some of the commoners mobilized by the *heervaart* in the County of Holland:\n\n > *die cuyper van Voorschoten, een out, arm man ende manc aen beide ziden; een jonc knechtkin, hiet Jan ende is licht 14 jaer out ende daertoe arm of Gerrit Cleve, een arm man van Zoeterwoude ende is ghescoert*/*ghestoert* \n > \n > the cooper from Voorschoten, an old and poor man and with a limp on both sides; a young stableboy named Jan, barely fourteen years of age and therefore poor, or Gerrit Cleve, a poor man from Zoeterwoude, badly injured/mentally insane.\n\n^(The last word depends on the quote. The former is used in Jansen & Hoppenbrouwers the latter in De Graaf.)\n\nThe extent to which the population mobilized in the rural parts of these lands were considered undependable at best is evident once we see that the counts and their deputies were often quite content with the commoners refusing mobilization, as that resulted in taxation (if they opted out before mobilization, with permission to do so) or fining (if they refused during mobilization) by the bailiffs, with the proceedings then used to hire proper *soldeniers*, mercenaries if you will.^(2)\n\n1. Jansen & Hoppenbrouwers (1977) p. 14, De Graaf (2004) p. 40,\n2. Jansen & Hoppenbrouwers (1977) p. 14, from receipts of 1362-1363 in the Dutch Court of Audit" ] }

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[ "https://www.reddit.com/r/Showerthoughts/comments/asa2nz/mulans_dad_would_have_never_been_asked_to_fight/" ]

[ [ "https://www.reddit.com/r/AskHistorians/comments/amebmy/saturday_showcase_february_02_2019/efm0n2y/?context=3" ] ]

{ "a_id": [ "cp3igry", "cp3j6pr", "cp3je9u" ], "score": [ 4, 3, 2 ], "text": [ "It's a great thing until someone whistle blows you. Then they're a snitch. \n\nThe government is equating it with giving classified data to the enemy like treason, espionage and the like. Really it's bullshit but that's their reason. ", "it *is* a good thing, in general. unfortunately, in the case of snowden, it harms the interests of the most powerful government in the world, so they make it a bad thing", " > Why is Snowden in trouble for whistleblowing?\n\nBecause he broke the law ... \n\nThat you oppose programs he leaked to The Guardian doesn't make leaking that classified information legal. " ] }

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{ "a_id": [ "c2wxvl7", "c2wxvl7" ], "score": [ 8, 8 ], "text": [ "It is usually worked on as \"hex,\" or [uranium hexafluoride](_URL_0_)", "It is usually worked on as \"hex,\" or [uranium hexafluoride](_URL_0_)" ] }

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[ [ "http://en.wikipedia.org/wiki/Uranium_hexafluoride" ], [ "http://en.wikipedia.org/wiki/Uranium_hexafluoride" ] ]

{ "a_id": [ "cwey7p8" ], "score": [ 6 ], "text": [ "There is no absolute reference frame, but the closest there is is the [cosmic microwave background](_URL_0_) reference frame. That is, roughly speaking, how fast we would be moving if we never accelerated since the Big Bang. The sun is currently moving 370 km/s from that reference frame. Earth is moving 30 km/s compared to that, and someone on the equator is moving 0.47 km/s compared to that. But since they're not necessarily in the same direction, you can't just add them up. The 30 km/s ends up increasing the average speed by only a little more than 1 km/s, which gets lost in rounding. The 0.47 km/s does even less." ] }

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[ [ "https://en.wikipedia.org/wiki/Cosmic_microwave_background" ] ]

{ "a_id": [ "c77q6mt", "c77tc07" ], "score": [ 5, 3 ], "text": [ "In terms of early examples of written humour (as it's very difficult to find stand-up comedians without written record), one of the earliest examples is the satirical script of the [Instruction of Dua-Khety](_URL_0_), an Ancient Egyptian work written in the 2nd millenium BCE (Between 2000 and 1700 BCE). It describes manual labourers during the time, while also exaggerating their features to grotesque proportions (stone-workers with crocodile claws, etc.). \n\nHope this helps!", "The plays of Aristophanes were very similar to, say, *The Daily Show* in that they often poked fun at current political and social issues, and often very specifically mocked certain people. A friend of mine had a paper published about that, I think, if you're interested I can dig up the citation for you." ] }

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[ [ "http://www.reshafim.org.il/ad/egypt/texts/instructions_of_kheti.htm" ], [] ]

{ "a_id": [ "c2q2od4", "c2q2od4" ], "score": [ 5, 5 ], "text": [ "I think they already invented it: [coma](_URL_0_)", "I think they already invented it: [coma](_URL_0_)" ] }

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[ [ "http://en.wikipedia.org/wiki/Coma" ], [ "http://en.wikipedia.org/wiki/Coma" ] ]

{ "a_id": [ "ctdaqcr" ], "score": [ 4 ], "text": [ "Apologies to the moderators, as I'm reasonably certain that I am breaking the 20 year rule here. Depends on how you count it. The *acts* described took place in the mid-90's up until 2003. The trial was in 2006-08, with the appeal continuing to 2010 and post-conviction proceedings well into 2012.\n\n***\n\nCharles Taylor was the President of Liberia from 1997-2003. Before that he ran a rebel group that fought for decades in Liberia. But he's not really the star of the story here. In 1977, while attending college at Bentley University in Boston, he fathered a son, colloquially known as \"Chuckie Taylor.\" Born as Charles McArthur Emmanuel, and changed his name legally to Roy Belfast, Jr. I mention this because he is an American citizen by birth.\n\nIn 2008, he was convicted of the crime of \"torture\" under United States laws (18 USC § 2340A) among other crimes, and sentenced to 97 years in prison. The substance of his conviction was running the Anti-Terrorist Unit or ATU of the Liberian state security apparatus, which ran several prison and forced labor camps, as well as, to put it lightly, death camps in which people were tortured, questioned, and publicly executed.\n\nMy sources come from the publicly available documents and pleadings, which can be found at *United States v. Belfast*, 06-cr-20758 (S.D. Fla. 2006). There is also the publicly available appeals court decision here: [*United States v. Belfast*, 611 F.3d 783 (11th Cir. 2010)](_URL_0_), which begins with the rather memorable recitation of facts: \"The facts of this case are riddled with extraordinary cruelty and evil.\"" ] }

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[ [ "http://caselaw.findlaw.com/us-11th-circuit/1531578.html" ] ]

{ "a_id": [ "cffvoys", "cffwdi7", "cffwm0f", "cffzr62", "cfg08cr", "cfg0r68", "cfg0rsp", "cfg0uv2", "cfg0x7w", "cfg1c53", "cfg1f66", "cfg2nrz", "cfg43ly", "cfg6yn0", "cfgbkto" ], "score": [ 31, 47, 3, 33, 8, 2, 2, 5, 2, 2, 2, 8, 3, 2, 2 ], "text": [ "The other country would be turned into a glass parking lot. That's the US's official stance on having WMDs used against them. \n\nNo doubt all channels would have a breaking message to seek shelter but it could possibly be too late. ", "The Emergency Alert System (EAS) would be activated over radio & TV informing people to seek shelter.\n\nDepending on the launch, it may even be destroyed as soon as it went up. The US invests heavily in Ballistic Missile Defense, using a network of satellites, land- and [sea- based radar](_URL_1_) and [AEGIS-equipped ships](_URL_0_). The best time to take out a nuke is on the way up, before the missile's independent warheads split off, so you're only shooting at the one target. More than likely, that country would have at least one warhead screaming down on it very shortly.\n\nIf they don't get it, they'll have a pretty good idea of where it will be headed because they'll be tracking the shit out of it. Even then, they don't have until it reaches the ground because airbursts cause greater damage.", "Try reading this book called \"Command and Control\". It really goes in depth about America's nuclear history. ", "We would shoot it down and then America the living shit of that country. ", "This is all you need to know. Skip to 5:45 \n_URL_0_", "Iron Man would fly in and divert the missile into an intergalactic portal.", "Submarine-launched missiles take seven minutes to reach their target, with no indication of who the originating country is (if any, and not a rogue sub). You'd be lucky to have enough time from an alarm to run down into the basement.", "I don't know, but as a Brit I'm safe, because [this is our programme](_URL_0_). The *ultimate* deterrent...", "Follow up question... \nIf a missile was launched, what would be the #1 target in the US? \n( if more missiles were launched, what would be #2-5 targets?). ", "The more interesting question is what would happen if some fringe group got control of a nuclear weapon and launches it on the US?", "Since the United States is so vast and the potential yield in other countries nuclear weapons would be relatively low, I would say such a move would be ill advised. Even the most powerful bomb ever detonated, the Tsar Bomba, could not deliver a strike powerful enough to deter an American retaliation. Simultaneously with a mass deployment of counter attack personnel, there will either be a retaliation with a low yield tactical nuclear weapons to avoid fallout and collateral damage in neighbouring countries or a blockade followed by a massive invasion assuming it is any of the current nuclear capable countries. \n\nThere will be widespread condemnation from the United Nations and ally countries. A blatant nuclear attack would undoubtedly provoke a powerful emotion known as fear, leading to mass panic. Depending on emergency services and leadership capabilities, chaos can likely be contained within weeks, maybe months. Unless you have the worst propaganda department in the entire world, the armed forces would likely receive a surge of applicants both due to Americans' fierce patriotism (see: days following 9/11) and current economic conditions.\n\nThen comes the ass kicking. It can come in many ways but most probably a tactical strike against the offending countries' military capabilities using a combination of low yield nukes and precision conventional munitions would precede a very careful invasion to replace the leadership and literally take over the country. A rogue nuclear nation can not be tolerated by the international community and there would likely be support for the \"rehabilitation\" of extreme supporters of the offending government. ", "That country would very shortly cease to exist. We would liberate them. ", "World War Mother Fucking 3! TEAM AMERICA BITCHES", "People would die", " > Like.. Would the US override all radio & tv stations and let people know?\n > Would they issue a mandatory evacuation? \n\nFirst off, let's dispense with all of these. The answer is no. In the event of a nuclear missile launch, there would be 30 minutes or less of warning. MUCH less if it was fired from a submarine sitting off the coast. There is barely enough time to alert the President in matters like this, alerting the public simply isn't part of the plan.\n\n > Would they even know where it's gonna land?\n\nYes. Missiles follow a ballistic path.\n\nAs to the overall question, note that all the other answers are mere speculation. As far as I know, the current US nuke response plan is not public knowledge. \n\nI *CAN* tell you what would have happened if the Russians had launched even a single nuke at the US from about 1961 to about 2003, because I am familiar with a charming little document called the Single Integrated Operational Plan, or SIOP. That was essentially the Pentagon's official war response plan to be enacted upon verification of a Soviet nuke launch, even of a single missile. Upon verification, the President was to be alerted at once, and he had to make the decision whether to hit back or not. The time allotted for that decision might be as little as two minutes (and he might have to make it after having just been rousted from bed at 2 in the morning). You might have heard Presidents making speeches about \"limited response\" and stuff like that, but the SIOP was the only plan the Pentagon had. \n\nIf the President elects to strike back, he gets the current nuclear authorization codes from a briefcase called The Football, which is kept nearby by a military officer at all times. He combines that with his Presidential authorization code, which he is supposed to keep on his person at all times (it was revealed the Bill Clinton actually misplaced his, and was too embarrassed to tell the Pentagon).\n\nAfter that, the plan is simple: launch pretty much every nuke we have at the Russians and a few affiliated locations. By the time Jimmy Carter came into office (the last President I have a hard figure for), the plan called for launching *TEN THOUSAND* nukes, all in the space of a few hours. Obviously, this was before anybody started taking the concept of nuclear winter seriously. But such a strike would have pretty much doomed all mankind on the planet Earth.\n\nAnd if you're not yet scared enough, let me just add that the order to launch a single Russian nuke was *actually issued* once. It was during the most tense part of the Cuban Missile Crisis, and an American warship detected a Russian sub in the area (which was in international waters). The commander of the ship didn't care much for that, so he ordered practice depth charges to be dumped on the sub to force it to surface.\n\nUnder the water, the captain of the Russian sub B-59 had been submerged for several days, and thus had not been in contact with Moscow (this was in the days before ELF underwater communications). He had no idea if war had already broken out or not, so he made the only logical decision a sub commander could make: sink the fucker who's shooting at us. He ordered a nuclear-tipped torpedo fired.\n\nWell, fortunately for the future of the human race, Russian protocol required the three top officers to agree on any use of nuclear arms. The captain and the political officer were all for it, but Vasili Arkhipov, the first officer, argued that it would be MUCH saner to surface and find out what the fuck was happening. The captain and political officer made all the usual Russian threats (bullets, gulags, end of career), but Arkhipov held firm, and the captain eventually surfaced the boat. Thus, the world did *not* end that day.\n\n\n" ] }

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[ [], [ "http://en.wikipedia.org/wiki/Aegis_Ballistic_Missile_Defense_System", "http://en.wikipedia.org/wiki/Sea-based_X-band_Radar" ], [], [], [ "https://www.youtube.com/watch?v=QBK3QpQVnaw&amp;feature=youtube_gdata_player" ], [], [], [ "http://www.americansweets.co.uk/ekmps/shops/statesidecandy/images/american-tropical-twist-flavour-trident-gum-212-p.jpg" ], [], [], [], [], [], [], [] ]

{ "a_id": [ "ddg1en6", "ddg1i6e", "ddg1idr", "ddg79tc", "ddgco9g" ], "score": [ 7, 282, 4, 15, 2 ], "text": [ "Even numbers (I-10, I-90, etc.) run east-west, with the number increasing from South to North. Odd numbers (I-5, I-95, etc.) run north-south, with the number increasing from West to East. ", "Primary routes have two digits. Odd numbered highways run north and south, with lower numbers in the west and higher numbers in the east. Even numbered routes go east-west, with the lower numbers in the south and higher numbers in the north.\n\nThree digit routes starting with an even number are loops within or around a city. Three digit routes with an odd number are spurs into a city. For such three digit routes, the last two digits indicate the primary route they are based on.", "In addition, three-digit US interstate routes are usually auxiliary routes (with the last two digits referring to the parent), such as a bypass around or through the city, or a short branch.", "Also related... the US Highway System's numbering is the same way but numbers ascend east to west, and north to south as to not have them confused with the interstate numbers. Hence why in California, for instance, they have US-101 and I-5, and in Idaho, where I live, they have US-2 and I-90. Needless to say, it works well except towards the middle of the US.", "Adding to the previous responses ... The Interstate numbers get higher the farther north you go. That is why Interstate 10 runs along the southern border. Interstate 94 runs near the northern border. I-90 is to the south of it, I-80 to the south of it, and so on." ] }

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{ "a_id": [ "d66e89e", "d66gdy0" ], "score": [ 3, 2 ], "text": [ "Because they believe converting people will get them into heaven. Really, it is just a pyramid scheme.", "In JW's teaching, the heaven is only for the chosen 144.000. The rest of the follower still stays on the earth which is reformed to be like the garden eden. And the reason they still do door to door marketing of their faith is not because they want to go to heaven, instead, they actually believe wholeheartedly that their teaching is the Truth, the good news so they call, and they're willing to go to extent as far as disowning their children to adhere to their believes." ] }

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{ "a_id": [ "c8q03wh" ], "score": [ 2 ], "text": [ "The authorship of the *La Historia Verdadera* is something that has been debated a bit more than the author of this article lets on, although I don't know of any other scholar off the top of my head that has made the assertion that Cortes himself wrote the piece. Historians have pointed to the fact that there is very little record of Bernal Diaz having participated in the Conquest beyond the text - which is unusual give the centrality he often grants himself in events. Large portions of the text have also been clearly borrowed from Gomara's version of Cortes' campaign.\n\nThere are, however, a number of factors which made a dismissal of the work's authenticity difficult. While the work is often fantastical, this was not out of the ordinary for medieval works - particularly pieces like this which were intended to be petitions to the Spanish Crown for financial support. Bernal Diaz, if he was the author, was writing during a period when the Conquest was coming under heavy scrutiny in Spain. Given is advanced age, financial troubles, and this large political context many Historians do not find the incongruities of the work wholly surprising. \n\nI cannot comment on the accuracy of Durverger's work given that I have not read it but I will say that many elements of *La Historia Verdadera* would not serve Cortes' interests very well. The author was often very critical of Cortes' leadership and intents as well as the overall Conquest. Many of Cortes' fabrications are best exposed by contrasting his *Cartas de Relación* with *La Historia Verdadera*. I personally do not believe Cortes to be the author but I would not say that such an idea is an impossibility." ] }

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[ "http://elpais.com/elpais/2013/02/12/inenglish/1360672838_941682.html" ]

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{ "a_id": [ "cfsp9mc" ], "score": [ 11 ], "text": [ "Same reason no one interfered with US invasion of Dominican Republic. It was our sphere of influence. Just like Eastern Europe was USSR's. No one was willing to risk global war. During the Cold War it was the countries more distant (Vietnam, Angola, etc) that were really up for grabs and fought over. The Truman Doctrine basically stated this. We wouldn't try to rollback Communism in Eastern Europe, but we would fight to prevent it in the 3rd World. " ] }

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{ "a_id": [ "cm7ert3", "cm7f0y1", "cm7f5ta", "cm7ltm8", "cm7tptv" ], "score": [ 5, 2, 3, 2, 2 ], "text": [ "Glucose monitors have been around for over 35 years. They were just bigger and slower.\n\nBefore then it was controlled through highly restrictive diets and insulin and oral medicines and everyone kinda hoped for the best. Bloodwork was limited to labs and hospitals.", "Based on some of my reading on the subject, before meters Type 1's used to \"taste\" their urine to see if it was sweet.", "Prior to glucometers, you would start with a dosing schedule of insulin and by trial and error you would eventually figure out your optimal dose. You basically had to go by the presence/absence of symptoms(light-headed, fatigued, etc.) or rely on lab results to determine a good dosing schedule for you. Forget about sliding scales and PRN insulin.\n\nEDIT: other poster reminded me that you can *smell* sweetness (sugar concentration) in urine. That is a sign that blood glucose is high and insulin is required, this info could be used to modify a dosing schedule or indicate a one-time dose is needed. I hope they didn't taste it as well... ew", "Urine test strips were around longer. The main limitation was they'd only detect grossly high glucose levels, around 180mg/dl and above. This could keep you alive, but not prevent long term damage, (generally around 150 or so and above) so complications were a lot more common prior to blood glucose monitoring.", "Diabetes has been documented to about 1500 BCE in Egypt, India, & China. Oftentimes, either tasting the urine for sweetness, or observing ants becoming attracted to the urine, were good indicators of having the disorder. " ] }

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{ "a_id": [ "evzcyt0" ], "score": [ 2 ], "text": [ "I believe it does so in response to cellular damage caused by UV light—hence why tanning beds cause you to get darker. If the cell notices an increase in UV damage, it creates more melanin. \n\nNot a very scientific answer as I don’t know the exact mechanism, but I hope that helps a little!" ] }

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{ "a_id": [ "cwh27mp" ], "score": [ 6 ], "text": [ "Medieval authors tended to divide history into six ages, which were mapped to the first six days of Creation in Genesis (and sometimes to the different stages of human life). Although variants existed, the most common schema came out of Augustine who situated the first age as from Adam to the Flood, the second from Noah to Abraham, the third from Abraham to David, the fourth from David to the Babylonian Captivity, the fifth from there to Christ, and the sixth age which began with the Incarnation and would continue until the end of time when Christ's return would inaugurate the seventh and eternal day. Thus, medieval thinkers, were they to speak of living in a historical period, would likely say that they were living in the sixth age of history. \n\nThere were other historical periodizations floating around as well, most famously Joachim of Fiore's division of history into three ages, of the Father from Creation to Christ, of the Son from Christ until 1260, and of the Spirit which was sort of eschatological culmination of history prior to the final judgment. As you might imagine, this view was popular in the years leading up to and immediately after 1260, but fell out of favor after Joachim was condemned alongside heretical groups who followed his teachings, and it became obvious that his prophecies weren't accurate. " ] }

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{ "a_id": [ "cjrdt7i" ], "score": [ 4 ], "text": [ "You may be confusing external, bulk, translational motion with internal, microscopic, random motion. They are independent. In a vacuum, an object's temperature will remain the same no matter how fast it is moving linearly through space. It must according to Relativity. Depending on what reference frame you choose, the object is moving a different speed. If speed were related to temperature, the object would have different temperatures as measured in different reference frames, which makes no sense.\n\nBut, bulk linear motion can be converted to internal random motion if the object collides with other objects. For instance, an object traveling through air collides with the air. In the process, some of its forward motion is converted to internal random motion and the object heat up. The faster an object travels and the denser the material it travels through, the harder it collides with the material and the more its loses kinetic energy to heat. As an extreme example, throwing an egg against a brick wall converts all of its kinetic energy into heat." ] }

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{ "a_id": [ "cggeica", "cggenuu", "cggenxs", "cggeqp9", "cggesv3", "cggetfh", "cgghj9a" ], "score": [ 3, 6, 3, 10, 3, 14, 2 ], "text": [ "you are missing the concepts of speed of light.\n\nNo matter on the point of view - you can run away from the speed of light of towards. The speed of light stays the same", "No. Just like light is always measured as travelling at c in all rest frames, massive objects (such as planets) are always measured as travelling at less than c in all rest frames. This is because no rest frame is the 'correct' rest frame, therefore motion has to obey physical laws in all rest frames.\n\nIf, in your example, an outside observer observed two planets each moving towards each other at speed v, which is very close to the speed of light, an observer on one of the planets (i.e. the rest frame of the planet) would observe the other planet moving towards them at a speed greater than v but less than c.", "1. Outside of a thought experiment, neither planet could travel *at* the speed of light.\n\n2. If the planets were to be traveling at the speed of light, two interesting phenomena would occur.\n\n First, observers on either planet would only be able to see light from objects in front of them relative to the planets' direction of motion. Light from objects \"behind\" them or lateral to their trajectory would not be able to overtake them.\n \n Second, since the \"oncoming\" planet is traveling at *c* as well as any light it may reflect (if it reflects any at all; see above), observers on the other planet would only receive said light at the same moment the implied collision takes place. The planets would be utterly invisible to each other until it was too late...\n\n It might be possible to detect their presence due to gravitational effects of their passage on other objects, but then relativity comes into play: since the planet the observer is on is also traveling at *c*, time dilation (the slowing down of time itself as one approaches light speed) might make any attempt at long term observation useless. Hundreds of thousands of years for a sub-luminal planet may pass in a single day for a planet at light speed. ", " > Both planets move with speed of light, but opposite direction\n\nAccording to relativity, things don't just have a speed. They have a speed *relative to something else*.\n\nSo if you're on a planet, you might chose to measure the speed of another planet relative to your planet. It will never exceed the speed of light.\n\nOr you might be on a spaceship, observing two planets moving towards each other. Neither of them will exceeding the speed of light relative to you. However, you might observe them approaching each other at a speed that doesn't exceed twice the speed of light.\n\nWhy does this work the way it is? Well, if you were on the spaceship, but I was on one of the planets, then time for me would be running at a different speed to the speed time is running for you. That means that you would see my planet approaching the other planet at something close to twice the speed of light, whereas I would see the other planet approach me at only something close to the speed of light.", "You have put your finger *exactly* on the difference between relativity and older Newtonian physics. If one object is approaching you from the left at nearly *c*, and something else is approaching you from the right at nearly *c*, *to someone on the left object* you seem to be approaching them at nearly *c*... and the object to your right seems to be approaching them at only an ever so slightly faster rate, but still less than *c*.\n\nIt's that observational difference that leads to all the rest of relativity - time moving at different speeds for different observes, distances being contracted depending on velocity, and so forth.", "Yes, there is a relative speed maximum. It's, paradoxically, *c*.\n\nThere exists a [velocity-addition formula](_URL_0_) that is a consequence of the special theory of relativity. You can calculate for yourself how fast the planets would measure each other. For example, if both went at half the speed of light, the other planet would seem to approach at four fifths the speed of light (or 0.8*c*).\n\nAs an aside, objects with mass cannot reach the speed of light, since they'd get so dense the energy needed to push them to *c* approaches infinity.", "Actually, if something was coming at you at the speed of light, you wouldn't be able to see it at all. In order for you to see an object, light from that object would have to reach you before the object itself does." ] }

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[ [], [], [], [], [], [ "http://en.wikipedia.org/wiki/Velocity-addition_formula" ], [] ]

{ "a_id": [ "efpscbv" ], "score": [ 3 ], "text": [ "They didn't \"decide\". That's a conscious motive that you're applying to the simplest organisms. \n\nThe simple answer is that you need more stuff to make more cells. Just like building a house, you need to get more lumber, bricks, drywall...etc to build more houses. The easiest way to get the biological molecules an organism needs to make more of itself is to consume them from another organism that already has them." ] }

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{ "a_id": [ "crb4zc9", "crb4zhu" ], "score": [ 3, 2 ], "text": [ "They lean. \n\nWhen you lean on a bike your center of mass isn't over the wheels anymore. That puts a torque on you and the bike. If your bike weren't moving that would mean you would just fall over. Since the bike is moving and you have a lot of angular momentum, it turns the direction that you are moving. \n\nNOTE BECAUSE THERE IS A LOT OF MISS INFORMATION ABOUT THIS: my answer didn't have anything to do with the wheels rotating. it would work just as well if you were sliding on an ice skate machine as with wheels. \n\nIt anyone would like the math worked out as proof I can do that. ", "It takes a little practice. There is some mechanical self-balancing in a bike, but a lot of it also comes from the rider shifting their body weight. You can lean into a turn to make the bike tilt enough to turn, but not fall over. First thing you should do, get used to riding straight with no hands. Then, make gradual turns, and as you get better at it you can make tighter turns. As you're learning, I wouldn't keep your hands in your pockets, but close to the handlebars in case you start losing control." ] }

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{ "a_id": [ "f5zt174", "f5zt34q", "f5zvl6g", "f5zwr1k" ], "score": [ 11, 7, 5, 4 ], "text": [ "because sometimes its the fact that someone is showing you that they care makes it easier for you to let it out", "I cry because it shows that someone actually cares. Most times I feel hopeless is because I feel I'm all alone.", "This is such a good question i hope you get a good, scientific answer. Its gotta be something about us being incapable of communicating our emotions without simultaneously expresisng them or something.", "It is psychological in nature. Crying is a natural sign of weakness, a sign of vulnerablility. Because, think about it. When you cry, can you think of doing anything else? Can you focus on a task? No, right? This is why people try not to cry in public. It 'distracts' them from the important things.\n\nBut when someone asks if you are OK, it is a shoulder to lean on. A crutch to hold. That's why people give up holding tears when they are offered help. As it makes them feel better, while having 'something to fidget with', to better focus, for lack of a better term." ] }

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{ "a_id": [ "fdhdd9f" ], "score": [ 3 ], "text": [ "There was a time, like in the 70's, when the distinction actually meant something. The radio stations were mainly playing \"pop\" (am stations) and \"rock\" or \"disco\" and \"r & b\" (fm stations)\n\nThe stuff people were listening to that didn't get play on the radio (outside of college stations) was more \"artsy.\" Think The Velvet Underground or Big Star or Captian Beefheart.\n\nToday, this term means very little as most of the new ideas and \"artistic\" approaches to music have been absorbed into mainstream pop culture.\n\nI suppose one could argue that things that are today called \"art-pop\" are *more* descendant from the art-pop of old, and less descendant of traditional western pop music. However, this is no longer a real separate category, it's a spectrum to be used in a descriptive manner (ie this music it more \"arty\" than that music)" ] }

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{ "a_id": [ "e1cm1cr" ], "score": [ 2 ], "text": [ "Juice contains water so you just boil it until that water is gone to make a more concentrated juice" ] }

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