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27gbrg | why do (more) women not take birth control pills continually to never have periods? | As a man, it sort of blew my mind reading in the thread on the front page that 1/4 of the "birth control" pills that come in a packet are placebos. Birth control pills prevent menstruation while they are being taken. It is only because women don't take these pills for 1 week out of a month that menstruation occurs.
Apparently, there are no major medical consequences to simply taking a continual dose of birth control pills. The only thing I could find from a cursory search is that minor ["unscheduled" bleeding can occur in the first months after adopting this method](_URL_0_). And, as a result, women who do will never have a period.
So, if having a period is generally unpleasant and if stopping it is possible and safe, why don't more women do it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/27gbrg/eli5_why_do_more_women_not_take_birth_control/ | {
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"It's actually a subject of debate whether taking oral contraceptive continuously has no medical consequences. The fact is that this is a fairly new idea, and there's no enough data to say what the long term effects would be.\n\n[This website](_URL_0_) gives a good rundown of the pros and cons. It seems like a majority of doctors think it might be a good idea for some women, but more research is needed before we can be sure.\n\nDisclaimer: I am neither a doctor nor a woman. However, I do talk to doctors and women from time to time.",
"Analogy is you need to do an oil change on your car every now and then....",
"As a female, even though periods are indeed unpleasant, they are also kind of a hormonal release and an indication everything is all good in the hood, know'm sayin? Men don't really understand the hormonal tempest that can swirl inside the female body. A period is the calm after that storm (PMS). Also the only time I have not had a period after puberty was for several months when I was extremely ill. My body was just not functioning properly. Also if I got pregnant, my period is a good way to tell early on something is seriously up. So for those reasons, I would not tamper with my body's natural process in that way. "
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1x4x97 | When light is emitted from a source; do the photons start moving at the speed of light or do they accelerate up to it? | askscience | http://www.reddit.com/r/askscience/comments/1x4x97/when_light_is_emitted_from_a_source_do_the/ | {
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"Photons always move at the speed of light, from the instant they come into existence."
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4hw3ii | Why aren't there pure ATP supplements available on the market as energy boosters? What would happen if you took these? | As ATP is often referred to as the energy currency of the cell, what would happen if one ingested ATP capsules? Would the person experience an energy boost, or would it prove to be toxic? | askscience | https://www.reddit.com/r/askscience/comments/4hw3ii/why_arent_there_pure_atp_supplements_available_on/ | {
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"Funnily enough, not a thing. The moment ATP hits the acidic environment of your stomach, it begins to hydrolyze into phosphate and adenosine (and probably further into adenine and ribose). In order to harvest the energy from this hydrolysis reaction, you need an enzyme or protein that can accept it. In the absence of that, the energy of hydrolysis gets wasted as heat. Very, very, very expensive heat.",
"While not ATP, there is an adenosine injection that's used to correct cardiac arrythmias. I've only seen it once and that was several years ago. According to what I recall from the drug information paper, it's for the treatment of tachycardia and has a half-life of only a few seconds in the body.",
"Inside the cell (intracellular) ATP is an energy currency, you are right.\n\nHowever, the point that is missed by many of the other posts is that extracellular ATP acts as a danger signaling molecule called a Damage Associated Molecular Pattern (DAMP). It is recognized by receptors on cell membranes called purinergic receptors, most specifically the P2X7 receptor.\n\nThe effect of extracellular ATP hitting cells, especially the immune system, is a sudden efflux of potassium from the cell and a concomitant influx of calcium. This causes an overload of the mitochondrial calcium pool, resulting in mitochondrial reactive oxygen formation and ultimately cell death.\n\nBasically, a ton of extracellular ATP would cause a ton of cell death throughout the body until it gets degraded. So yes, it would be toxic.\n\nIn fact, your body has machinery to make sure extracellular ATP remains low (a small amount can be a useful signaling molecule) by releasing nucleases into the extracellular space.\n\nSource: did my PhD on the ion flux caused by extracellular ATP signaling in the immune system (among other things)."
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8tdv9p | how do people who live in eastern asian countrys eat so much yet stay so healthy? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8tdv9p/eli5_how_do_people_who_live_in_eastern_asian/ | {
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"By healthy I assume you mean lean with a low body fat percentage. It all comes down to the units of energy consumed versus the units of energy burned; some people burn more calories with more physical activity while others can consume a lot more without getting \"fat\" because they carry a lot of muscle mass.\n\nGenetics might play a factor in this along with your specific diet. Anyone can get lean and strong with enough effort and discipline. ",
"This should be tagged as biology, not culture. Weight gain/loss is determined by how many calories you take in, compared to those you expend based on your baseline metabolism and activity level. Ingredients can have more or fewer calories, but healthy food and unhealthy food with the same amount of calories will cause the same weight gain - you will simply feel differently after consuming it.\n\nA few things to think about on your end are snacks between meals or drinks during meals - this is frequently where people consume calories in significant amounts. Try taking a day where you count every single thing.\n\nOn their end, keep in mind that if you see videos of these events, they are likely not the norm. People don't take videos of their everyday meals, they take videos of interesting food they eat, or of interesting events in their lives.",
"Less added sugar, less carbs. When you eat a diet where you get your energy based off of carbs you are running on glucose, basically your body is always in an insulin rush. This makes you fat. If you get most of your energy from good fats insetad of sugars youre body will shed it's fat.\n\nSo more meat based fats or pure plant based fats (olive oil, coconut oil etc, not vegetable oil), butter and fat are better for you than the things they've tried to tell us are healthy (vegetable shortening, vegetable oil, margarine).\n\nPeople in East Asian cultures tend to eat more protien and vegetables. Even rice isnt normally enough net carbs (carbs minus fiber) to push them over.\n\nIn the western world everything is carb based, if it's not we add wheat or corn into it for no reason. We also have added sugars in processed foods. If you don't want to be fat only buy food from the outer perimeter of your grocery store (meat and produce) and skip the aisles of processed foods.",
"I’m not a nutritionist but asian cuisine (there’s different types) is lots of rice and noodles, vegetables, fish and fish based products\n\nThe regular “western” diet is lots of butter, bread, milk, pasta/noodles, and added sugar \n\nThere’s a debate between fat/carbs but different diets probably play a roll\n\nAnother thing is fast food, some countries that have been getting Newley introduced to fast food have been getting fatter "
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5h1ben | why aren't password special characters universally agreed on? | I'm not asking about the length or use of caps. I'm wonder about why isn't there a universally agreed upon standard of special characters (the !@#$ most make you use) that can be used by all password programs? Some allow a ! but not a ?, but another does the opposite. I just want to come up with one sweet and difficult password to use across all platforms. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5h1ben/eli5_why_arent_password_special_characters/ | {
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"Because there is no standards group maintaining this. And because some special characters have special meaning in certain locations. It wouldn't matter if the person writing the password code knew what they were doing and used modern best practices, but there's still some older code that uses older patters where having a ? in the message means something like \"move on to the next field\".\n\nAlso, please don't use one sweet and difficult password across all platforms. The biggest danger these days isn't a hacker guessing your password- any halfway decent service will lock them out after a few attempts. The biggest risk is someone stealing a password database from one website (maybe one which doesn't protect the passwords as well as they should), them having all the time in the world to crack the passwords, and then trying the same username/password combination on other popular sites. For this problem, it would actually be better to have a weaker but unique password on each website.",
"Other than the answer /u/popisms gave, the major reason is just piss-poor development. From a software development standpoint there is no reason whatsoever to blacklist characters in a password. \n",
"Software developer here,\n\nI have some domain knowledge on this subject and I also have acquaintances in some internet and information security companies, who specialize in things of this nature.\n\n > I just want to come up with one sweet and difficult password to use across all platforms.\n\nDon't do that. Per se.\n\nWhat you want to use is a password manager program aka a \"key ring\" program. This program can typically be installed on a USB stick for Windows, Linux, and Apple (you should have all 3). On the stick will be the key ring itself, a file that is an encrypted password database. It can also store the username and the login url and other notes for you.\n\nWhat you'll do is have one, sweet, master password that you will memorize, which unlocks your key ring. The program maintains passwords for all your needs, and will put the password you need into your clipboard, (typically) encrypted so all you have to do is paste it into the password field of whatever. You never have to see it or know it.\n\nThese programs do way more than just store passwords. When you enter a new client and password, you specify all the constraints on that password - length, special characters allowed or banned, required complexity, etc - and it will generate a secure password for you, one that is heuristically difficult and too complex for you to memorize. You never have to need to actually know or see it. If you need a new password, the program can generate a new one for you and store it in your key ring.\n\nJust as you don't leave your keys in your car, you don't leave your keys in your USB port. If you need a password, plug it in, retrieve the password, and unplug the stick. Don't use this stick for anything else, this is it's purpose. You can get tiny thumb drives practically for free and attach them to your keychain. Keep a backup drive in your dresser or even better, a lock box at your bank - they still offer those services and are basically the only reason to have any sort of business with a traditional local brick and mortar bank.\n\n > What if I'm using a computer that won't let me plug in a USB stick or run a program off it.\n\nYou're talking about using a public access computer. You need to seriously consider why the hell you would want to use a public computer that isn't yours, you can't trust, and should assume the very real possibility it's been compromised. I absolutely would never trust a library or university computer, as they're huge targets for this very reason. Expect no privacy and no right to privacy on such a machine. Move on. Your FB post can wait, if you had no other means.\n\n > I'm not asking about the length or use of caps. I'm wonder about why isn't there a universally agreed upon standard of special characters (the !@#$ most make you use) that can be used by all password programs? Some allow a ! but not a ?, but another does the opposite.\n\nSecurity is hard and service providers are *astonishingly* terrible at it. The people in charge of these sorts of decisions are often using extremely dated knowledge and/or technologies, or are ignorant, arrogant, and lazy. There is *ZERO* excuse why every password doesn't support unicode character password of arbitrary length without it reducing down to old technology, bad knowledge, or slack.\n\n---\n\nYou're not defending against people, but programs. The most important thing is your password is long. Second is that it uses a wide character set.\n\nAutomated attacks that try to brute force passwords for a given known user account will try to guess common passwords. So a complex or long password can defeat that.\n\nBut hackers are going to break into a system using an exploit, not a password, and steal the password file. It doesn't contain your password, but a \"hash\", which is generated from it and can't be reversed to reveal the password. They're going to use multi-terabyte \"rainbow\" tables, which is a database of hashes to passwords to look up your hash and instantly know the password. These tables are generated before hand, and for every additional BIT in your password, the table has to double in size. And generating these tables can takes months, and are per target - so what works for Target won't work for Amazon because of how each service is going to \"salt\" their hashes to make them more unique. So if they generated a table for every US English keyboard UTF-8 printable character password up to 64 bytes long (what you would typically type in on a keyboard), and your password is 65 bytes, you're almost certainly safe (mathematical flukes called hash collisions mean a different password can produce the same hash, it's just as valid as your password for your account, with modern crypto, the're essentially - ELI5 explaination - impossibly rare)."
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3xlvb5 | if the constitution protects against double jeopardy, how can trials go an appellate court? | If someone has already been convicted, how can they be tried for the same crime twice? Isn't this against the 5^th amendment? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3xlvb5/eli5_if_the_constitution_protects_against_double/ | {
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"In what way would it violate the rule? Keep in mind that the *defendant* is the one who asks for the appeal; without the appeal, he is guilty, and the appeal can't actually convict him (it's not a second trial). ",
"The process that happens in an appellate court or other higher court is not considered a separate trial, but rather a continuation of the original trial. What the appellate court tries to determine is whether the first court did a good job deciding the case, not (directly) if the defendant is guilty or not. The American Bar Association has a good explanation [here] (_URL_0_)."
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90z982 | why is it so hard to get that old 'hand drawn' look in modern anime/cartoons using computer animation? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/90z982/eli5_why_is_it_so_hard_to_get_that_old_hand_drawn/ | {
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"It's not done very often because animating something that high quality would take a really long time. It's possible, just insanely time consuming.",
"There's a lot of reasons why old hand drawn animation looks different than today's computer animation. \n\nComputer animation can still be hand drawn with a tablet or Cintiq, but often times it'll be a mix of hand drawn poses and reused poses or parts (for example you may have a library of 100 different hand poses or mouth shapes to reuse). This saves a lot of time and keeps the drawings consistently \"on model\", but definitely has a different look to it. The more you reuse a library of poses/parts, the more likely the animator will plan their scenes with those poses/parts in mind and the more it looks \"Flashy\" (or maybe these days \"Toon Boomy\"). There were ways of achieving the same effect in older animation by tracing over parts of previous poses or reusing entire scenes, but even with tracing there are going to be some differences. This is probably most noticeable in computer animation that only uses a handful of mouth poses; even if it's just subconsciously, you can tell that the same 12 or 15 mouth shapes are being used for dialog, and maybe some additional shapes for extreme expressions. Even worse is if you're limited to a set of pre-approved poses; the animation starts looking very \"samey.\"\n\nAnother difference is that old animation was drawn on paper, then clear celluloid was laid over top to add the ink lines, and then flipped over and the back was hand painted. This leads to a number of artifacts that are difficult to reproduce in digital animation or simply undesired. First, you have slight inconsistency with lines from frame to frame, called \"line boil\". For a big expensive production (like Disney or Richard Williams) the animators are *very* careful to keep those lines as consistent as possible; Richard Williams in particular was a perfectionist and would require his animators to redo a scene if the lines were off by as little has half the width of a pencil stroke. This can still happen on a digital production but it's easier to avoid and easier to fix, so even low budget TV shows usually won't have line boil unless it's intentional.\n\nOther artifacts included mis-colored cels that would sneak in, especially in TV animation where you had tight deadlines and low budgets; it's just too expensive to ink a new cel, repaint it, and re-shoot it. Fun fact: because film was so expensive, the camera operator was often the highest paid person on the production; you had to get it right the first time or you can destroy your budget. In addition to mis-colored cels, there was also inconsistent thickness to the paint which leads to subtle changes in the color. \n\nThere are no color inconsistencies in computer animation because you're usually going to be working with a preset color pallet and pre-colored body parts/props. Even for productions that need to be colored frame by frame, if you spot an error it's really cheap and easy to fix it with digital ink and paint software. And since it's not shot on film anymore, there's no film grain or issues with focus being slightly off. Digital colors can also be much more saturated and sharper contrast than what you get with film. \n\nThe cels also aren't 100% transparent, they block out a small percentage of light. This meant that scenes with more cels stacked on top would darken the background elements. As the scenes play out, you can see this darkening/lightening of the background elements as layers of cels are added and removed. With digital animation, you can have hundreds or thousands of layers without the darkening/lightening effect. \n\nAnd finally, animation style has changed quite a bit over time. Compare the \"rubber hose\" style popular in the 20's and 30's to the limited style that UPA popularized in the 50's, to the zip and pose style in the 2000's. There's also house styles; there's a clear difference between Warner Bros and Disney style, or Pixar and Dreamworks. It's not just the animation style, either, it's also things like character design and color choices. You can certainly emulate older animation styles on the computer, but audience tastes change over time and animation directors want to stand out from the crowd so you don't see the older styles as often in modern productions. Computer animation also lets you do interesting things that would be prohibitively expensive for hand drawn animation. Consider the characters in Foster's Home for Imaginary Friends; many of those designs would be an absolute nightmare for hand drawn animation, especially on a TV budget. But thanks to Flash and a huge library of reusable body parts, poses, and animation sequences, the costs are kept lower and you get a really unique cast of characters and an interesting animation style."
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zhjnj | how american college applications work. | Basically I have to start applying for colleges and I have no idea what the fuck I'm doing. On the Chapman website, it says they have a school especially for film, Dodge, which has its own application specifications. If I want to minor in film but major in something else, do I have to apply to both Chapman and Dodge? Are they the same school? If I go in undecided but decide I want to take some film classes, do I have to apply then, or can I just take the classes? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/zhjnj/eli5_how_american_college_applications_work/ | {
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"So, for a bit of clarification, mostly for the stuff below, a university is made up of colleges. a college of liberal arts a college of business, et cetera. \n\nyou only have to apply directly to college if you want to major in it. you can usually minor in a field without being certified by the college, while you do need to be certified in order to major. you can also declare a major, usually at any time within your first two years, but you have to reach higher standards than if you started out in the college if that major happens to be competitive.\n\nthe rules are different for every school so I would talk to an advisor at that particular school if you want better information.",
"You would apply just to the one where you anticipate majoring. This won't even be an issue with all schools, though. Universities are typically divided up this way, but colleges are not. "
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5zj96q | How has the historiography of the First World War changed over time? | When I was learning about WWI in high school (mid-2000s) I was taught that the War was inevitable. Going off my history textbook, a global war was pretty much bound to happen due to things like the overlapping network of alliances, great power competition, and technological change.
Has this always been the narrative surrounding the First World War? For example, would textbooks in the 1920s or 1930s have portrayed the war as the "inevitable" result of European international relations? Did the Second World War change how the causes of the First World War were viewed?
I'm not asking whether or not the "inevitable" view is "correct", but rather has that always been the main way of presenting the narrative. | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/5zj96q/how_has_the_historiography_of_the_first_world_war/ | {
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"In my experience, most of the revisions were made within the overall narrative of WWI that you've described, focusing instead on who exactly was to blame for the ultimate outbreak of the war. For most of the 20th century the scholars seem to have been preoccupied with the location of the \"smoking gun\", and it shifted from Germany, to the Western alliances, to Austria-Hungary, and back to Germany, as well as some other participants. Or, in other words, the conditions made the war possible, but the relevant guilty party (or parties) was the one(s) ultimately responsible for the outbreak, and, having the sole responsibility for the start of the war, were the ones who theoretically could have prevented it. The reading of WWI as \"inevitable\" came about a bit later, and tended to spread the blame a bit more evenly, but in effect it prioritized long-term collective responsibility, while short-term causes were still largely attributed to individual actors (or blocs of actors). \n\nMore specifically however, recently there was an uptick in scholarship that argues that Would War I was NOT inevitable, and the *general* war could have been avoided, in some cases up until August 4th. \n\nThe best work that deals specifically with this notion is probably Margaret Macmillan's \"The War that Ended Peace: Road to 1914\". \n\nMacmillan argues that the most important lurch towards the war took place between the Sarajevo assassination on June 28, and August 4 1914. She insists that the most crucial decisions that ended up leading to the outbreak of the hostilities were taken by a relatively small group of men in that period, and that almost every single one of them had the opportunity to take a different decision on certain matters. She also points out the proliferation of various factors that were making a general war less likely at the time, such as labour movements, investment and capital flows, and migration and international communication. Unfortunately, I don't have my copy of the book at hand right now, so I cannot provide any specific detail as per her argumentation, but she dedicates a lot of time to going over the personalities of the most important decision-makers at the time and the circumstances and the overall context which they were forced to make decisions in. \n\nEDIT: Slightly changed the argument presented in the first paragraph.",
"It sounds like you're asking about the historiography of the *causes* of WWI, and certainly there has been an unending argument about that since 1914 itself. What's unique about WWI is that, being the first major conflict of the 20th century, it's not that sources are few, there are simply far too many. Millions of pages of diplomatic correspondence or memoirs or newspaper articles, it's to the point that it's physically impossible to read it all, and that if you're picky enough about what you look at, you can reasonably blame any of the belligerent powers for the outbreak, and as a matter of fact there is at least one major work blaming each possible combination of powers: it was France and Russia, it was Germany and Austria, it was Germany alone, it was Britain, it's staggering how much you have to sift through with WWI.\n\nTo get back to your point, I think there are two major works you have to read if you want to see the \"top hits\" of academia on the causes of WWI: Fritz Fischer and Christopher Clark.\n\nIn the 60's Fischer wrote a monumental work called (in English) *Germany's Aims in the First World War* and to make a long story short he put more or less the sole blame of WWI on Germany, or at the very least for making a global war out of a local Balkan dispute. He makes a compelling case and he absolutely had evidence to back it up, going into minute detail researching German govt documents. For a long time after the debate was whether you agreed with the \"fischer controversy\" or not. A main critique of fischer is that he takes german documents at face value (for example concerning the Schlieffen plan, there are arguments that it was really a ploy to get more funding to the armed forces, the plan uses units that didn't exist at the time). If anyone more familiar with Fischer's work would care to jump in please feel free to do so, I'm much more familiar with clark\n\nIn 2012 Christopher Clark published what's become a landmark work on WWI origins called *The Sleepwalkers: How Europe Went to War in 1914*, and his main thesis is that so much time and ink has been spent exploring *why* WWI happened, we've ignored *how* it did. He cites a quote from Bulgarian historian Buldinov \"once we pose the question \"why\", guilt becomes the focal point.\" Sleepwalkers explores the chronology of events of the July crisis and how the actions of one party's actors were perceived by another, and from my point of view at least provides very convincing arguments, especially with what is known as the security problem: defensive actions that are taken by one state out of fear of a rival are taken as aggressive by the other. Germany's actions that are taken as belligerent by Fischer seem much more reactionary when put in the context of an atmosphere of paranoia about encirclement. Each power was scared of the ability of other nations' presses to force their govt to push forward with hardline nationalism while simultaneously discounting their own (each govt of the time paid very special attention to the leading newspapers of their rivals). The Entente was by no means an anti-german coalition and Clark makes a convincing argument that within a couple of years Britain and Russia would have probably stopped cooperating and returned to seeing eachother as rivals. I'm afraid I'm not doing Clark's work justice these are just isolated points, but his main contention is that the war wasn't inevitable, but it's actors *believed it to be so*, they saw themselves as on an irreversible path, and so could not see viable diplomatic alternatives open to them and so \"sleepwalked\" to war.\n\nClark's work is very popular right now, and with good reason I believe, especially since its focus on taking \"blame\" out of the equation it's very popular in German circles, and for precisely this reason there are British historians who criticize it. For now at least Sleepwalkers is probably the best example of modern historiography of WWI origins"
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1y3z91 | 16th century Church of England question? | Say if i walk into one of the churches and wait for an hour or so and then stood up and said the what the preacher was saying was a lie? would i be killed,thrown out, or would there be a whole different thing that situation? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1y3z91/16th_century_church_of_england_question/ | {
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fpjh33 | i have a cpap machine for sleep apnea. how similar / different is it from a medical ventilator? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fpjh33/eli5_i_have_a_cpap_machine_for_sleep_apnea_how/ | {
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"The CPAP machine is simply designed to keep a small positive airway pressure (hence the name) in order to keep the airway open. You still must breathe, it doesn't do it for you. A ventilator actually will breathe for the person, so it will put positive then negative pressure , usually through a breathing tube that's down the trachea into the lungs, not through a mask at all. It will also filter the air coming out and going in, to ensure a good, clean, sterile breathe with no contamination of the surrounding environment."
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4regmv | what makes popular music recordings you hear on the radio sound so "good"? | Compared to home recording or local recording studios, what makes recordings bands like Maroon 5 sound "better" than other bands? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4regmv/eli5what_makes_popular_music_recordings_you_hear/ | {
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"Professional mixing and mastering engineers.\n\nBasically, for bands as large as Maroon 5, you have multiple professionals mixing the song to get it to sound as clean, clear and crisp as possible. The better the mix engineer, the better the song will sound. \n\nBut it also all comes down to the ear of the mixing engineer. you can know the ins and outs of song mixing/editing but having a good ear for audio quality is probably most important imo.\nSo naturally, having multiple people working on it, or at least having another engineer checking over the first engineers work is like having someone edit your writing.\neven the best writers in the world can benefit from an outside revision/opinion.\nbut again, the bigger the band, the better the mixing engineer hires will be\n\nMastering is **basically** eqing/cleaning up the final audio file of a song and making it louder through compression \n\nThe human ear thinks louder= sounds better\n\n"
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[]
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|
a3bnsd | how come no one has prosecuted the president yet? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/a3bnsd/eli5_how_come_no_one_has_prosecuted_the_president/ | {
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"If your gonna take a shot at the king, you better not miss. Any prosecutor worth their salt is gonna make sure all of their ducks are in a row before bringing anything forward, and with something as big as impeachment there are a lot of ducks. For reference watergate took roughly 2 1/2 years from start to finish and that never even reached the impeachment stage. This investigation is going light speed in comparison. "
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||
6s3g83 | why isn't drug testing mandatory for politicians? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6s3g83/eli5_why_isnt_drug_testing_mandatory_for/ | {
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"Politicians are the ones that would put these new laws in place. Also, some govern places where certain drugs are now legal. They also don't operate heavy machinery or have a direct impact on public safety. "
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3d7oig | Marquis de Lafayette's uniform | I'm trying to find if anyone knows what Lafayette's epaulets looked like. I'm doing a sculpt of him based off a Houdon and I cant seem to make out what it was. It kind of looks like a french revolution cockade. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/3d7oig/marquis_de_lafayettes_uniform/ | {
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"There are very few surviving epaulettes from the Revolutionary War, otherwise I'd send you towards an image of an original. Instead [here is a link](_URL_1_) to trusted reproduction site, you'll want to look specifically at the cockade epaulette. I am assuming that you're working off of the [Charles Wilson Peale](_URL_0_) portrait as well. The gold braid on top would either be a plain weave ribbed tape (possibly some small design in it) or a literal braid with 20 or so sections. The fringe is bullion, essentially like a coiled spring. Most often these have a buttonhole at the top and a loop underneath the bottom that a shoulder strap goes through to attach."
]
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"https://commons.wikimedia.org/wiki/File:Marquis_de_Lafayette_2.jpg",
"http://www.najecki.com/repro/OffNCO.html"
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|
mbxcy | Is hemp really a miraculous plant that could replace dozens of products at a cheaper cost? | askscience | http://www.reddit.com/r/askscience/comments/mbxcy/is_hemp_really_a_miraculous_plant_that_could/ | {
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"A better way to judge the papers you're seeing is who actually did the research and the methodology section, rather than writing it off solely because it is on an organization like NORML's site. It may be the case that NORML has gotten permission to publicize a study (or purchased the rights to publicize a study) that one could only access through a for-pay digital database.\n\nAs for all the items you talk about, it'd be doubtful you'd find all the information in a single place. There are a lot of very different factors you're asking about.\n\n[This paper has some discussion in the right vein and might at least lead you off in the right direction.](_URL_0_)",
"Hemp is produced in a number of countries: _URL_0_\nSo you could probably get a reasonable idea of how useful it is in the real world for various things by seeing how widely used it is in those places and what they use it for.",
"I have a question. Would hemp fiber/pulp be profitably useable as a replacement for wood fiber in soft, 2 or 3-ply toilet paper?",
"Hemp isn't a 'miraculous' product, per se, but it is useful and could be a cheaper or more effective replacement for a few different materials if grown industrially. The reason people seem to sing its praises and make it sound like a miracle product is because right now in North America you pretty much can't grow it industrially because it has been lumped in with marijuana plants as a controlled substance. People think this is silly because you can't get high using hemp and so they point out that you can make all sorts of products out of it, such as paper, textiles, rope, etc. The reason we can't is political, not based on evidence or reason.\n\nBasically, imagine if cows were illegal to raise industrially. You could say 'but they can be used for high-yield production of meat, milk, leather, gelatin, glue, etc. without consequences that are any worse than raising pigs or sheep for similar purposes.' Whether cows are the best choice for any of that is debatable, and also beside the point. The fact that they are (in this hypothetical situation) illegal to raise for reasons that are not based in fact is silly.\n\nWhether hemp is indeed the most efficient or effective way of producing some or all of the things you mentioned is debatable. Keeping it as a controlled substance when there is no danger of it being used as a narcotic is less defensible in a lot of people's minds, hence the seemingly hyperbolic claims of its value.\n\nThe wikipedia article on industrial hemp is quite good and well-referenced: _URL_0_\n\nTL;DR: Industrial hemp could potentially be used for lots of stuff, but we can't grow it in North America because of arguably dubious policy and thus people sometimes overstate its value as an industrial crop. I make no claims as to the relative efficacy of hemp as an industrial crop vs the alternatives.\n\nEdit: I posted this from my phone and didn't realize that this was /r/AskScience. Apologies if my reply isn't up to subreddit standards, I did my best.",
"This is a friendly reminder from the moderators of AskScience to please refrain from posting a top-level comment to this post unless you have a scientific, evidence based point to contribute. Anecdote and speculation are not welcome, but followup questions certainly are!",
"Like bamboo, hemp can be made into rayon. It can also be made into paper. The industrial process needs to be tailored to use hemp as an input stock. It's good for oil, a food, etc. \n\nIf we're going to talk about the environmental aspect, we need to really look at the agricultural practices involved. Hemp can produce more fiber per acre in a shorter time span than tree plantations. But that kind of forestry isn't actually that bad environmentally, and intensive hemp farming can be detrimental to the soil if not done in rotation. \n\nEconomically, there may be more land that could grow hemp than trees, and still leave that land open for a winter crop. ",
"One increasingly useful property of hemp fibre is that it can be grown with less water than cotton. Cotton production is extremely wasteful of water; more so than any other crop. It is the chief reason for the destruction of the [Aral Sea](_URL_0_), for example.",
"hemp can reduce deforestation to an extent. replacing our paper with renewable hemp paper would have a drastic impact on clear-cutting etc.\n\nof course its extemely difficult ot build a house out of hemp, so trees wouldnt totally stop being harvested, but it would make a serious impact for sure.\n\nas ensignredshirt mentioned, a lot of the claims are a result of not being able to use it at all, so everyone is pointing at what can be done with it. the fact remains though that hemp would do more than just be a cheaper alternative, it could seriously improve our devestation of resources.\n\nHemp can also be made into a plastic, reducing the needs for many harmful chemicals. hemp can be used as fuel, (makes way more sense than corn, a food source), and would move towards domestic dependency and less drilling possibly.\n\noverall, the merits of the plant are one thing, but the real wonder is the effect felt on industries today that are doing what hemp could be doing.\n\nof couse there would be problems. many industries would lose money, but that is the nature of the field i suppose.",
"Some relevant data would be: 1) the plastic strain in hemp fabric after cyclic loading compared to cotton fabric; 2) a comparison of fiber damage after abrasion of hemp fabric compared to cotton; 3) the resistance to photodamage of hemp fabric compared to cotton; 4) the macronutrient profile of hemp seed compared to alternate nuts such as pecans, walnuts, linseed, etc.; 5) the carbon sequestered per acre per year of hemp vs comparable industry crops, e.g. pine trees, cotton, palm, etc.; 6) the change in consumption habits based on consumers appeal to hemp products e.g. taste, texture, etc. I can keep going but you'll notice none of that data is in this thread or very easily available in one place. My anecdotal ideas are valuable and were meant to inspire these ideas.",
"I think that the following paragraph is very telling:\n\n[\"The world leading producer of hemp is China with smaller production in Europe, Chile and North Korea. While more hemp is exported to the United States than to any other country, the United States Government does not consistently distinguish between marijuana and the non-psychoactive Cannabis used for industrial and commercial purposes.\"](_URL_0_)",
"The problem with hemp rope is that, as a natural fibre, it rots. Synthetic ropes can be left submerged in sewer for years and be none the worse for wear.\n\nThere are also synthetic ropes that are both stronger and lighter.",
"In the summer of 2008 I did a LOT of research on hemp as an alternative energy source (among other things) for policy debate. You're right on the source issue, I have a document with hundreds of cites for articles and a lot of them are not peer reviewed and are not from the most reputable sources. \n\nTwo things I did notice were prevalent in the literature and were from fairly reputable sources: Firstly, hemp is a great source for biofuels as it has high cellulose content (I don't know much about biology so if I phrased that wrong, I'm sorry.) Secondly, it grows just about anywhere. As the U.S. loses more and more farmland due to soil erosion and negatives of large scale, intensive agriculture hemp makes more and more sense. The reason is because hemp will grow on land that can't sustain any other commodity crop. Hemp can even grow on the huge amounts of land we have that were never good for farming *anything*. We even found some evidence that hemp cultivation could have a restorative effect on soil.\n\nThese two factors combine in a great way- we need alternative fuels and the only reason ethanol is being produced is because of huge subsidies. Corn is just too expensive without government aid to be an economical fuel source in the long term. However, we've got massive amounts of land that we can't use for anything. It's just sitting around, no one is getting paid for that land. If we converted the majority of this land to hemp production and biofuels, the U.S. would have new job opportunities without the worry of crowding out other industries (except maybe corn, but corn is a fucked up industry anyway.) Also, since the land is cheap and the hemp is easy to grow, it would be a pretty affordable fuel source. We need the fuel, we need the jobs, there's really no reason not to try it.\n\nI can maybe dig up some sites later if there's demand, but I have a shitload of work to do right now.",
"Not a lot of talk here about the land and water needs as well. I don't know if it would be commerically viable to water hemp and I don't know if hemp has these crazy yields in conditions that are not improved by humans. It is worthwhile to note that we do not water forests or tree plantations. Some plantations might be irrigated in some way in the east, I don't know, but I am fairly confident that water isn't diverted to plantations unless it is very plentiful already.\n\nAlso, where would all the land for hemp come from? A lot of forest products come from forests that already exist? Are we going to clear forests and plant hemp plantation? People talk a lot about how terrible tree plantations are. Is an intensively managed stand of native plants really that much worse than an intensively managed plantation of exotic plants?\n\nSo it's important to realize what hemp is going to need, specifically to perform at such an optimal rate. It needs land, water, enough sun, and probably a shit load of fertilizer. \n\nIf someone really has a problem with what I said I can get journal articles to support what I said, but I feel it's more or less common knowledge, at least in an academic sense.",
"reddit response 2\n\nI have been a agriculture biologist specializing in insects and plants since the mid 90's, with a recent station in the Peace Corps in west Africa. In my professional opinion, we just don't know. Modern analytical tools are just now being used to determine if hemp is in fact better suited than current crops such as cotton, soy or white pine, mostly in western European countries. The hurdles for conducting even basic research in the US are such that most botanist do not bother even proposing it for grants. Peer reviewed research in countries with more sober policies are the only source for current comparisons, but these studies do not always address issues unique to North America. While marijuana went underground and indoor after prohibition, hemp did not. During this time, cotton for example, has undergone many changes and improvements ( not to mention eradication of boll weevil) as a result of research money being spent on this particular crop. So far, we have illogical regulatory hurdles and 60 years of lost research time, the next problem is public perception and consumer demand. Every farmer that I have ever met, in the US and the countries in the world that I have visited, will grow what ever crop they think will get the most money at market (this includes subsistance farmers) and many are willing to try new crops. If hemp were legal and cost effective to produce, trust me in that there will be a farmer with a huge machine to harvest and process it in no time. Many tobacco farmers make their living off farms sometimes as small as 5 acres (2 ha), but want to transition to speciality crops as domestic demand drops. Hemp would just be another seed that they could try to make a living from, as there is no way for a US farmer to make a living off 5 acres of corn or soy.\nThis bring me to my point, we need further research. We will have to start with land grant univerisites growing test plots in different areas of the country before we can even begin to discuss what the economics and benefits of hemp are. In the short term, hemp has potential to replace tobacco as a speciality crop for a niche market. \n\nFinally, I would like to say that there is no crop that is harvested that does nor result in net soil nutrient loss. Put simply, if you put a seed in the ground, grow a plant then harvest and remove it either whole or just one part of it, you have to put something back. On an industrial scale, you have to fertilize, even tree farms. Hemp does exclude other weeds and plants when grown densely, reducing the need for herbicides, but if it is planted on a industrial scale, there will be insect problems, trust me. \n\nAnd now for olpapad's link request...\n\n_URL_0_",
"Advocates could we breed a version of hemp that doesnt have any effects on the human mind when ingested in some way? If then it would be fairly easy to get it approved right?\n",
"A better way to judge the papers you're seeing is who actually did the research and the methodology section, rather than writing it off solely because it is on an organization like NORML's site. It may be the case that NORML has gotten permission to publicize a study (or purchased the rights to publicize a study) that one could only access through a for-pay digital database.\n\nAs for all the items you talk about, it'd be doubtful you'd find all the information in a single place. There are a lot of very different factors you're asking about.\n\n[This paper has some discussion in the right vein and might at least lead you off in the right direction.](_URL_0_)",
"Hemp is produced in a number of countries: _URL_0_\nSo you could probably get a reasonable idea of how useful it is in the real world for various things by seeing how widely used it is in those places and what they use it for.",
"I have a question. Would hemp fiber/pulp be profitably useable as a replacement for wood fiber in soft, 2 or 3-ply toilet paper?",
"Hemp isn't a 'miraculous' product, per se, but it is useful and could be a cheaper or more effective replacement for a few different materials if grown industrially. The reason people seem to sing its praises and make it sound like a miracle product is because right now in North America you pretty much can't grow it industrially because it has been lumped in with marijuana plants as a controlled substance. People think this is silly because you can't get high using hemp and so they point out that you can make all sorts of products out of it, such as paper, textiles, rope, etc. The reason we can't is political, not based on evidence or reason.\n\nBasically, imagine if cows were illegal to raise industrially. You could say 'but they can be used for high-yield production of meat, milk, leather, gelatin, glue, etc. without consequences that are any worse than raising pigs or sheep for similar purposes.' Whether cows are the best choice for any of that is debatable, and also beside the point. The fact that they are (in this hypothetical situation) illegal to raise for reasons that are not based in fact is silly.\n\nWhether hemp is indeed the most efficient or effective way of producing some or all of the things you mentioned is debatable. Keeping it as a controlled substance when there is no danger of it being used as a narcotic is less defensible in a lot of people's minds, hence the seemingly hyperbolic claims of its value.\n\nThe wikipedia article on industrial hemp is quite good and well-referenced: _URL_0_\n\nTL;DR: Industrial hemp could potentially be used for lots of stuff, but we can't grow it in North America because of arguably dubious policy and thus people sometimes overstate its value as an industrial crop. I make no claims as to the relative efficacy of hemp as an industrial crop vs the alternatives.\n\nEdit: I posted this from my phone and didn't realize that this was /r/AskScience. Apologies if my reply isn't up to subreddit standards, I did my best.",
"This is a friendly reminder from the moderators of AskScience to please refrain from posting a top-level comment to this post unless you have a scientific, evidence based point to contribute. Anecdote and speculation are not welcome, but followup questions certainly are!",
"Like bamboo, hemp can be made into rayon. It can also be made into paper. The industrial process needs to be tailored to use hemp as an input stock. It's good for oil, a food, etc. \n\nIf we're going to talk about the environmental aspect, we need to really look at the agricultural practices involved. Hemp can produce more fiber per acre in a shorter time span than tree plantations. But that kind of forestry isn't actually that bad environmentally, and intensive hemp farming can be detrimental to the soil if not done in rotation. \n\nEconomically, there may be more land that could grow hemp than trees, and still leave that land open for a winter crop. ",
"One increasingly useful property of hemp fibre is that it can be grown with less water than cotton. Cotton production is extremely wasteful of water; more so than any other crop. It is the chief reason for the destruction of the [Aral Sea](_URL_0_), for example.",
"hemp can reduce deforestation to an extent. replacing our paper with renewable hemp paper would have a drastic impact on clear-cutting etc.\n\nof course its extemely difficult ot build a house out of hemp, so trees wouldnt totally stop being harvested, but it would make a serious impact for sure.\n\nas ensignredshirt mentioned, a lot of the claims are a result of not being able to use it at all, so everyone is pointing at what can be done with it. the fact remains though that hemp would do more than just be a cheaper alternative, it could seriously improve our devestation of resources.\n\nHemp can also be made into a plastic, reducing the needs for many harmful chemicals. hemp can be used as fuel, (makes way more sense than corn, a food source), and would move towards domestic dependency and less drilling possibly.\n\noverall, the merits of the plant are one thing, but the real wonder is the effect felt on industries today that are doing what hemp could be doing.\n\nof couse there would be problems. many industries would lose money, but that is the nature of the field i suppose.",
"Some relevant data would be: 1) the plastic strain in hemp fabric after cyclic loading compared to cotton fabric; 2) a comparison of fiber damage after abrasion of hemp fabric compared to cotton; 3) the resistance to photodamage of hemp fabric compared to cotton; 4) the macronutrient profile of hemp seed compared to alternate nuts such as pecans, walnuts, linseed, etc.; 5) the carbon sequestered per acre per year of hemp vs comparable industry crops, e.g. pine trees, cotton, palm, etc.; 6) the change in consumption habits based on consumers appeal to hemp products e.g. taste, texture, etc. I can keep going but you'll notice none of that data is in this thread or very easily available in one place. My anecdotal ideas are valuable and were meant to inspire these ideas.",
"I think that the following paragraph is very telling:\n\n[\"The world leading producer of hemp is China with smaller production in Europe, Chile and North Korea. While more hemp is exported to the United States than to any other country, the United States Government does not consistently distinguish between marijuana and the non-psychoactive Cannabis used for industrial and commercial purposes.\"](_URL_0_)",
"The problem with hemp rope is that, as a natural fibre, it rots. Synthetic ropes can be left submerged in sewer for years and be none the worse for wear.\n\nThere are also synthetic ropes that are both stronger and lighter.",
"In the summer of 2008 I did a LOT of research on hemp as an alternative energy source (among other things) for policy debate. You're right on the source issue, I have a document with hundreds of cites for articles and a lot of them are not peer reviewed and are not from the most reputable sources. \n\nTwo things I did notice were prevalent in the literature and were from fairly reputable sources: Firstly, hemp is a great source for biofuels as it has high cellulose content (I don't know much about biology so if I phrased that wrong, I'm sorry.) Secondly, it grows just about anywhere. As the U.S. loses more and more farmland due to soil erosion and negatives of large scale, intensive agriculture hemp makes more and more sense. The reason is because hemp will grow on land that can't sustain any other commodity crop. Hemp can even grow on the huge amounts of land we have that were never good for farming *anything*. We even found some evidence that hemp cultivation could have a restorative effect on soil.\n\nThese two factors combine in a great way- we need alternative fuels and the only reason ethanol is being produced is because of huge subsidies. Corn is just too expensive without government aid to be an economical fuel source in the long term. However, we've got massive amounts of land that we can't use for anything. It's just sitting around, no one is getting paid for that land. If we converted the majority of this land to hemp production and biofuels, the U.S. would have new job opportunities without the worry of crowding out other industries (except maybe corn, but corn is a fucked up industry anyway.) Also, since the land is cheap and the hemp is easy to grow, it would be a pretty affordable fuel source. We need the fuel, we need the jobs, there's really no reason not to try it.\n\nI can maybe dig up some sites later if there's demand, but I have a shitload of work to do right now.",
"Not a lot of talk here about the land and water needs as well. I don't know if it would be commerically viable to water hemp and I don't know if hemp has these crazy yields in conditions that are not improved by humans. It is worthwhile to note that we do not water forests or tree plantations. Some plantations might be irrigated in some way in the east, I don't know, but I am fairly confident that water isn't diverted to plantations unless it is very plentiful already.\n\nAlso, where would all the land for hemp come from? A lot of forest products come from forests that already exist? Are we going to clear forests and plant hemp plantation? People talk a lot about how terrible tree plantations are. Is an intensively managed stand of native plants really that much worse than an intensively managed plantation of exotic plants?\n\nSo it's important to realize what hemp is going to need, specifically to perform at such an optimal rate. It needs land, water, enough sun, and probably a shit load of fertilizer. \n\nIf someone really has a problem with what I said I can get journal articles to support what I said, but I feel it's more or less common knowledge, at least in an academic sense.",
"reddit response 2\n\nI have been a agriculture biologist specializing in insects and plants since the mid 90's, with a recent station in the Peace Corps in west Africa. In my professional opinion, we just don't know. Modern analytical tools are just now being used to determine if hemp is in fact better suited than current crops such as cotton, soy or white pine, mostly in western European countries. The hurdles for conducting even basic research in the US are such that most botanist do not bother even proposing it for grants. Peer reviewed research in countries with more sober policies are the only source for current comparisons, but these studies do not always address issues unique to North America. While marijuana went underground and indoor after prohibition, hemp did not. During this time, cotton for example, has undergone many changes and improvements ( not to mention eradication of boll weevil) as a result of research money being spent on this particular crop. So far, we have illogical regulatory hurdles and 60 years of lost research time, the next problem is public perception and consumer demand. Every farmer that I have ever met, in the US and the countries in the world that I have visited, will grow what ever crop they think will get the most money at market (this includes subsistance farmers) and many are willing to try new crops. If hemp were legal and cost effective to produce, trust me in that there will be a farmer with a huge machine to harvest and process it in no time. Many tobacco farmers make their living off farms sometimes as small as 5 acres (2 ha), but want to transition to speciality crops as domestic demand drops. Hemp would just be another seed that they could try to make a living from, as there is no way for a US farmer to make a living off 5 acres of corn or soy.\nThis bring me to my point, we need further research. We will have to start with land grant univerisites growing test plots in different areas of the country before we can even begin to discuss what the economics and benefits of hemp are. In the short term, hemp has potential to replace tobacco as a speciality crop for a niche market. \n\nFinally, I would like to say that there is no crop that is harvested that does nor result in net soil nutrient loss. Put simply, if you put a seed in the ground, grow a plant then harvest and remove it either whole or just one part of it, you have to put something back. On an industrial scale, you have to fertilize, even tree farms. Hemp does exclude other weeds and plants when grown densely, reducing the need for herbicides, but if it is planted on a industrial scale, there will be insect problems, trust me. \n\nAnd now for olpapad's link request...\n\n_URL_0_",
"Advocates could we breed a version of hemp that doesnt have any effects on the human mind when ingested in some way? If then it would be fairly easy to get it approved right?\n"
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tpu65 | Is color an intrinsic property, or is it just the way we process different wave lengths? And could other species "see" totally different colors? | I've been wondering about this for some time now. Different colors are caused by different wave lengths of light. However It seems nothing in the property of the wave itself "carries" a specific color. So I reasoned, we only see a specific color, because we evolved to see that specific color. I.e. yellow is yellow to us because we see it yellow. Is that right?
If that is the case, would be possible for other species to see different colors than humans? This is not about the inability to process different colors (i.e. dogs see no colors, because they are colorblind). It is about a species which can differentiate between colors, but would experience it differently. Does such a species exist and/or would it be possible? If yes, who do they experience colors?
I'm not really sure how to express this idea, I hope this made it clear. | askscience | http://www.reddit.com/r/askscience/comments/tpu65/is_color_an_intrinsic_property_or_is_it_just_the/ | {
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"Color is actually a complex combination of light wave lengths and perception. The human eye (typically) has three types of cones which are sensitive to different light wave lengths. Adding those wave lengths up gives us our perception of color. One of the big tricks, is that there are essentially an infinite number of combinations of wavelength for us to perceive the exact same color. So two things may appear red to us, but at a wavelength emitting level, they're totally different. \n\nIn rare cases, humans can have additional receptors (I know there have been cases of 4 instead of the usual 3... I don't know if there have been more beyond that). Those individuals will see the world significantly differently from most of the rest of the population.\n\nAs for other critters, plenty of animals have more (or fewer) types of cones. This means they can perceive different combinations of colors. The [Mantis Shrimp](_URL_0_) for example, can see something like 12 wavelength (including photoreceptor for the ultra violet range). ",
"I'm not sure I understand your question perfectly, but I can give some insights on excatly how the color vision works\n\nThe very first step of detecting color takes place in the retina. We have specialised cells that respond differently to color (which, I think, are called cones, but I'm not sure). These cells detect light by having what are called photoreceptors proteins. In the human system we have 3 different types of color-sensitive receptors, and one color-sensitive cell has only one type of receptor.\nThe difference between the receptors is that they respond differently to different wavelengths. We can caracterise this difference by looking at the absorption profile of each photoreceptor (= how well the molecule absorbs different kinds of light).\n\nPhysically, different objects emit different spectrum of light. You can caracterise the color of an object by its spectrum. However, when we look at the color, we project this spectrum on only 3 dimensions, that is the energy of each kind of receptor when it is subjected to that light.\nSo we can perceive that 2 objects that have different physical color (spectrum), have the same perceived color.\nSo, in that sense, perceived color is not an intrinsic property because it depends on the chemico-physical properties of human photoreceptors. However, you can give a physical definition of color which is the emission spectrum of the object.\n\n\nI hope this is clear enough. Don't hesitate to ask me questions"
]
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uyq7w | A question about old-fashioned TV antennas | I don't even know how to put this.
In the old days, when we had "rabbit ear" style antennas on top of TV sets, it seems there was always one person in the house who affected the TV reception when nobody else did. That one person could make the TV signal go all static just by moving around. Sometimes happened on radio sets too. Sometimes if they moved a certain place, they could keep the signal perfect just by staying there. Even the position they held would affect this, i.e. raising their arms or standing on one leg.
What the heck **was** that? Are some people just naturally more conductive?
| askscience | http://www.reddit.com/r/askscience/comments/uyq7w/a_question_about_oldfashioned_tv_antennas/ | {
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"Some people step really heavily. This could affect things.\n\nBesides that, probably just observer bias."
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s4xvg | Why don't scientists use natural units more often? | Why don't we normalize certain fundamental physical constants like the speed of light, the gravitational constant, charge of an electron, etc. to values that are easier to work with. It seems foolish to have an electron's charge be -1.6 x 10^-19 C when we could create a new unit and set it equal to 1. The same goes for mass, why use the international prototype kilogram as the base unit for kilogram when we could set it to something based on nature. I know this has been done to some extent with Planck units but I still don't encounter it much.
My thinking is that if we did this more often it would eliminate the need for various constants that reconcile our arbitrary metric units with natural ones.
| askscience | http://www.reddit.com/r/askscience/comments/s4xvg/why_dont_scientists_use_natural_units_more_often/ | {
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"By eliminating the need for various 'constants' you have just replaced the issue with various different units, haven't you? I'm not sure I follow completely.",
"I use units that are useful. When you have to use 10^53 of a unit, it's not useful.",
" > It seems foolish to have an electron's charge be -1.6 x 10-19 C when we could create a new unit and set it equal to 1. \n\nFunnily enough, someone beat you to this observation. When you're doing certain things in physics, it's quite common to use the electron volt:\n\n_URL_0_\n\nBasically, people use the most convenient units.\n\n_URL_2_\n\n_URL_1_",
"As an engineering student I use mol and kmol all the time. I believe chemistry is using a rather fundamental unit."
]
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"http://en.wikipedia.org/wiki/Electron_volt",
"http://en.wikipedia.org/wiki/Astronomical_unit",
"http://en.wikipedia.org/wiki/Atomic_units"
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|
1k428c | if it takes so many processors to simulate one second of human neural activity, why are processors so much more accurate and faster than brains? | I read an article recently (if anyone could provide a link, that would be appreciated) that said that it took lots of processors (I forget the number, but it was a lot) and about 40 minutes to recreate one second of the brain working. What I don't understand is how I can perform long calculations, perform thousands of instructions to keep a game running, and run an entire operating system on my computer, when it takes me seconds to do two digit addition or memorize a phone number. Processors seem so fast and accurate, so why does it take so many to simulate the much slower and sloppier human thought? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1k428c/if_it_takes_so_many_processors_to_simulate_one/ | {
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"Short answer: because human brains are doing things WAY more complex that are also much more important, evolutionarily speaking. Math equations beyond \"two lions means twice the lions that want to eat me\" are not as important as regulating bodily functions, cataloging dangers, remembering safe behaviors, socializing and procreating, etc. I'll post a whole thing about sight to show you just how complex it can get.",
"Processors are very good, extremely accurate and very fast - but only at certain types of problem.\n\nA processor can very easily solve any problem that can be expressed using an algorithm - a series of steps that can be followed, one at a time, to tell it how to solve the problem.\n\nThe difficulty is that our brains don't work this way. There is no algorithm that we know of which can accurately simulate what the brain does or how it does it. Our brains, although nowhere near as good as computer processors at solving logical or mathematical problems that can be written as an algorithm, have very complex internal workings that are very good at solving problems that *can't* be written as algorithms.\n\n**ELI5 analogy:** think of brains and processors as types of car. They look very different, but appear - at first glance - to do similar jobs.\n\nThink of the brain as an off-roader. And the computer processor as a racing car.\n\nThe racing car (processor) can get around a race track (solve mathematical problems) extremely quickly. The off-roader (brain) can get around the race track (solve the same problems) too - but it will take a bit longer.\n\nOnce you're off-road, though (thinking about more complex problems) the off-roader (brain) is king. The racing car (processor) probably can't get around the course (solve the problem) at all - and if it can, it will have to be done very slowly and very carefully.",
"A neuron detects whether or not a certain threshold has been passed, and if so, it 'fires', passing the signal on to perform some action.\n\nThis can be modeled as an equation with a number of terms equal to the number of 'inputs' - in the case of a brain, the number of synapses. It is basically summing them together and answering whether or not it should set itself off. This is between one and a hundred thousand for a human brain, though some animals have so few that we can actually create circuits to interface with them (such as snails).\n\nAssuming an average firing rate per neuron of 10/second, 10,000 synapses per neuron, and a hundred billion neurons, this gives a naive approximation of ten thousand million million additions per second, and is probably on the low side even for this naive model.\n\nThis does not model learning or memory of any sort, or mental state (happy/sad, etc). \n\nDifferent neurons in your brain have different numbers of different receptors for different neurotransmitters. The relative densities of these chemicals are not constant, nor are the receptors. This adds some orders of magnitude more complexity to each neuron, multiplying the above still further.\n\nOf special note is that this is *all bandwidth*. A single neuron firing is not just a computation - but a transmission, to potentially a hundred thousand neighbors, representing, in our incapable-of-learning-or-memory toy scenario, of a megabyte per second of data, per neuron.\n\nThat's all any individual neuron can do, however. Alone, its power is quite limited, and there are certain computational functions that require multiple layers of neurons - not just individuals - to work.\n\nSo when you see\n\n43+19\n\nFirst, the neurons in your eye detect the edges of those symbols, and transmit said symbols to your brain, where pattern recognition decodes these signals into their base concepts. These then get grouped into larger tokens, '4 and 3 next to each other is 43'. Then the + signal triggers some level of conscious thought that this is actually a problem.\n\nFor addition, there's actually a circuit in our brain that is somewhat 'optimized' for this, where it recognizes the sequence and can process a meaningful answer very quickly (there is some weird Japanese mental abacus game that abuses this, I forget the term - but the speed is ridiculous).\n\nFor multiplication, this isn't true, however, and we have to rely on our memory and learned techniques. This is, in comparison, ridiculously slow - you're manually applying patterns, you've got no built in hardware to do this.\n\nProcessors come with this hardware purpose-built for just this exact task. Even the subunit in our brain is a kludge in comparison - processors are getting close to being optimized down to the atom for this.\n",
" > Processors seem so fast and accurate, so why does it take so many to simulate the much slower and sloppier human thought?\n\nThe lots of processors you mentioned aren't simulating \"human thought\" - they are simulating [neurons](_URL_0_) (the cells that form the brain). Neurons does a whole sort of things, and we don't quite understand it all yet - but we know that the activity of neurons doesn't originate *just* human thought, but regulate processes through the whole body, most of it being unconscious (that is, you don't even know about it).\n\nThe reason it takes so much processing power to simulate a brain is because it's *huge*! In the human brain, there is about 100000000000 neurons (1 followed by 11 zeroes) and each one is connected to about 10000 other neurons, and they all work in parallel, that is, at the same time. If you had a computer with that many processing entities (such as: 100000000000 processors), each one connected to tens of thousands other entities, you could have a shot in simulating the brain in real time. But you don't!\n\nWe are stuck with processors that can't handle well such massively parallel task. For example, modern graphic cards have about 1000 very simple processors, and the connections between them are very limited. What we usually call \"processors\" - the CPU - are usually restricted to 8 more complex \"cores\", which are processors inside the CPU.\n\nWe try to cope with this using the fact that modern processors operate much more faster than a brain. Each neuron can fire typically once in some milliseconds, while the fastest processors make a operation once in some nanoseconds. There is one million nanoseconds in one millisecond, so if a neuron could be simplified to a single operation you could hope to simulate one million neurons in real time, with a single processor, going from one to another in succession (do a operation for the first, one for the second, etc). But each neuron is connected to many others - and you need to consider each such connection - and modern processors suck at dealing with very large amounts of data. Also, neurons are more complex than a single operation anyway. (PS: the reason the brain is so \"slow\" is because firing faster consumes more energy, and the brain is already the biggest consumer of energy in the body)\n\nBut there is the even greater problem of memory bandwidth (how to transfer very large amounts of data between parts of the computer), because memory is likely to be the bottleneck for such massive tasks. Data transfer in modern computers have a centralized, top-down structure, where each subsystem is connected to other using \"buses\", like traffic flow (smaller roads connected by avenues). When processing too much data, the bus might become congested, making each system wait for data transfer. This is different from the decentralized, massively interconnected network of neurons, which is much more like a p2p network.\n\nI also point that any such simulation won't tell us what the brain would actually do, because we have to simplify the theoretical model of a neuron to make the simulation feasible. So the simulation is slow *and* inaccurate.\n\nI wrote some bits on a reply to the currently most upvoted answer [here](_URL_1_) but it reads a bit more technical."
]
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7279r1 | if alcohol has been proven to cause cancer and other diseases, why aren't bottles covered in warning labels like cigarettes? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7279r1/eli5_if_alcohol_has_been_proven_to_cause_cancer/ | {
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"Ahoy, matey! Yer not alone in askin', and kind strangers have explained:\n\n1. [ELI5: Why are there health warning labels on cigarettes and not McDonalds, soft-drinks, processed meat, or on the side of Supercars and Bikes? ](_URL_1_)\n1. [Why is Alcohol not illegal because of how much harm it brings people and society? Why is it not treated like other drugs? ](_URL_0_)\n1. [ELI5: Why are tobacco products required to have health warnings on them when other unhealthy products such as Alcoholic drinks and Soda drinks don't? ](_URL_2_)\n",
"There are warning labels on alcohol, they cover the subjects of Fetal Alcohol Syndrome and Drunk Driving. Generally speaking, you have to be a a heavy drinker to substantially increase your risk of cancer/cirrhosis due to alcohol which doesn't apply to most drinkers. Hence, the reason a warning label isn't as warranted as it would be for smoking. "
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"https://www.reddit.com/r/NoStupidQuestions/comments/6bc9g8/why_is_alcohol_not_illegal_because_of_how_much/",
"https://www.reddit.com/r/explainlikeimfive/comments/3q7epx/eli5_why_are_there_health_warning_labels_on/",
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o5155 | Is it possible to make a laser that releases X-rays or gamma rays? | We've had lasers and Masers for decades now it is possible to make a coherent beam of x-ray or gamma radiation or for that matter very low frequency radio waves?
Would you be able to trigger a subcritical mass of radiactive material this way? Or perhaps use it in x-ray imaging to reduce scatter? Couldn't you use it to give someone a lethal dose of radiation from very far away? | askscience | http://www.reddit.com/r/askscience/comments/o5155/is_it_possible_to_make_a_laser_that_releases/ | {
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"It doesn't work by the same principles as other lasers, but [free electron lasers](_URL_0_) can produce virtually any wavelength of coherent photons.\n\nEdit: it's also possible to use a regular laser and [backscatter the photons off a high energy electron beam](_URL_1_). It's like bouncing a tennis ball off the front of a high-speed train. I don't think the resultant photons will be coherent"
]
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"http://en.wikipedia.org/wiki/Free-electron_laser",
"http://prl.aps.org/abstract/PRL/v90/i5/e055002"
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1f8ruf | How and why did the North-American states unite into the United States? | I was reading some political discussions in comments to this article; _URL_0_
and a lot of people seemed to think that the size of the US makes it tough to come up with any social security/medicare system that would 'stick' and function properly, like they have to some extent in Denmark.
So, what's against splitting up the United States and letting the states governed themselves, as I believe was the whole purpose behind having a United States; if you don't like the government in one place, go up the road a ways and try on the other side of the next state line. Seems federal legislation has all but covered those state lines under layers of ink on paper to me, but perhaps i'm wrong.
What is the purpose of having a United States Government, why was it founded? Does it still function in that way? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1f8ruf/how_and_why_did_the_northamerican_states_unite/ | {
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"Originally that is how the United States was created. A loosely related country of sovereign states. Each state printed it's own money, had it's own laws, provided for the welfare of their citizens, had it's own army. Basically the Articles of Confederation made the Federal government weak as possible. That presented problems, a lot of problems. \n\nEach state had one vote in congress.\n\nCongress didn't have the power to tax. \n\nIt couldn't regulate trade. Foreign or domestic.\n\nThere was no national court system.\n\nLaws required 9/13 votes to be passed.\n\nUnder the articles the states didn't care for each other or the national government. They didn't even support it sometimes. Shay's rebellion proved that the national government couldn't raise in army in a time of need something needed to be done. And that is when we drafted the Constitution of the United States.\n\nTo answer you question about states being split up, it already happened once of course and it didn't end well. This time even if they weren't to secede violently causing a civil war it still couldn't be done. States rely SO MUCH on federal aid. If they leave the Union it's gone. Most states couldn't maintain themselves without MAJOR changes. Also without that aid the luxury of everyday life is diminished. Schools, highways, recreational places would soon be left untouched to clear up money. \n\nTo answer your question about why the Government was created was well to establish a functionable country really. The US under the Articles pretty much failed. The federal government wanted some kind of authority. They needed armies to defend themselves, taxes to support themselves, they needed certain laws that would be applied everywhere and a court to support them. They also wanted a fair representative government that could work together for the greater of the country. However over the years, kickstarted by FDR the federal government has grown stronger. Since it is stronger and provides things states needs it makes it really hard for states to be \"split up.\"\n "
]
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nb262 | Does earth appear bigger on the horizon than over head when astronauts see it from the moon?
| Did they see the same effect as we see the moon from earth?
| askscience | http://www.reddit.com/r/askscience/comments/nb262/does_earth_appear_bigger_on_the_horizon_than_over/ | {
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"Well, the Earth doesn't set if you're standing still on the moon because the moon is tidally locked with the Earth. But that aside, were you to walk so far that you make the Earth set, yes it would appear bigger because of [the way we perceive the sky](_URL_0_).",
"It stands to reason that the same effect would occur on the moon.\n\nHowever, the same side of the moon always faces the Earth, so nobody would ever see an Earth-rise or Earth-set unless they were travelling around the moon. ",
"Well, the Earth doesn't set if you're standing still on the moon because the moon is tidally locked with the Earth. But that aside, were you to walk so far that you make the Earth set, yes it would appear bigger because of [the way we perceive the sky](_URL_0_).",
"It stands to reason that the same effect would occur on the moon.\n\nHowever, the same side of the moon always faces the Earth, so nobody would ever see an Earth-rise or Earth-set unless they were travelling around the moon. "
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psstc | Questions about nose picking and other socially unacceptable habits | Is there a reason we do them even though they're socially unacceptable?
Are there any inherent risks or health benefits to habits like nose picking?
In a general sense, how do habits like these form, and how can they be unlearned? | askscience | http://www.reddit.com/r/askscience/comments/psstc/questions_about_nose_picking_and_other_socially/ | {
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"Risks: Small but real risk of infection, which in turn [can spread to the brain.](_URL_0_)\n\n > Nose picking (rhinotillexomania) can lead to infections in the nose, which is situated very close to the brain. They share the same blood supply. Getting an infection anywhere in the area doctors call the \"danger triangle\" presents a good cause for alarm.\nThe danger triangle can be traced from one corner of the mouth, over the bridge of the nose, and down to the opposite corner of the mouth. Any time infection in this area occurs, there is the very rare but very real risk that the infection can spread to the brain."
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lhcbs | how the nes zapper gun (like the one used in duck hunt) knew where you were pointing on the screen. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/lhcbs/eli5_how_the_nes_zapper_gun_like_the_one_used_in/ | {
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"The Zapper doesn't actually \"shoot\" out light. Instead, it's the reverse: it's a light sensor. When you pull the trigger, the screen turns black and the targets (ducks, discs, enemies, etc.) would flash a white square. If the Zapper is pointed at a white square, it registers as a hit. This is also why it's possible to cheat by pointing at a bright light source (light bulb, window, high-brightness TV, etc.)",
"[Really great video about how the Zapper works, also answers your question.](_URL_0_)",
"The Zapper doesn't actually \"shoot\" out light. Instead, it's the reverse: it's a light sensor. When you pull the trigger, the screen turns black and the targets (ducks, discs, enemies, etc.) would flash a white square. If the Zapper is pointed at a white square, it registers as a hit. This is also why it's possible to cheat by pointing at a bright light source (light bulb, window, high-brightness TV, etc.)",
"[Really great video about how the Zapper works, also answers your question.](_URL_0_)"
]
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12k486 | why does usa elect their president based on who gets the most electoral votes and not by popular vote? | It is to my knowledge that in 2000, 48.4% of every American who voted wanted Al Gore as president, yet George W. Bush who had 47.9% won. Why is that? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/12k486/eli5_why_does_usa_elect_their_president_based_on/ | {
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"Cause the people who wrote the constitution realized that Americans could not be trusted to vote.\n\nTherefore the electoral colleges were instituted to correct 'mistakes' the voters made",
"These vids explain far better than I could:\n\n* _URL_1_\n* _URL_0_\n\nEnjoy.\n\n",
"Probably the best reason for the Electoral College I've seen in modern times is Sandy.\n\nThe US is very regionally fractionalized. This means that the NE will likely all go blue and the south all red. If we went on straight popular vote then a natural disaster suppressing turnout in one part of the country but not effecting another could change the outcome of the election.\n\nWith the Electoral College the damage of widespread low voter turnout in a single region but not another is negated since that region's EC votes are based on it's total population not the percentage of the population that voted.",
"It's a system designed to balance the different states. Without the electoral college, only the heavily populated states would matter. With the electoral college, several states in flyover country matter. It's designed to help balance out the large and small states. It's not perfect, but what is?",
"At the start of the country, many of the people who wrote the constitution saw the US as a strong alliance of many \"states\" rather than a single nation. The President was meant to be a representative of the many states that made up the alliance, not a representative of the people directly. ",
"The US was founded by many rich and educated men. In a time where education was considered a luxury that only the rich had, most people were uneducated, especially the lower classes. The founders of the US knew this, and were afraid of the common people electing an incompetent man as president. The electoral college was designed to correct the people of they made mistakes.\n\nThere's also stuff in the Federalist papers about how the Framers believed that republicanism was better than democracy and that democracy was the degenerate and corrupt form of republicanism, but that requires more in depth explanation than a five year old would understand.\n"
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2bt3p4 | why is it that some people absorb information easily while others can't? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2bt3p4/eli5_why_is_it_that_some_people_absorb/ | {
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"It is training. Also - we absorb different kinds of information differently. For example I usually have no problem picking up new math/logic concepts, but I can't keep up with history, and can only understand music from a math/order standpoint.",
"If you pay attention to something you find interesting, you'll remember it. If you aren't paying attention, or don't find the material interesting, you won't remember it. By absorbing, I assume you mean remembering something long-term. It's not scientific, just based on my experience."
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3f2jm1 | With the sea levels rising, what's happening with mountain heights? | They are measured in an above sea level scale, right? Does that mean that the mountains will never be as high as they are today? Will the mountain height charts be changed? | askscience | http://www.reddit.com/r/askscience/comments/3f2jm1/with_the_sea_levels_rising_whats_happening_with/ | {
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"In a simple sense, yes, elevations are referenced to sea level, but in reality, things are much more complicated. Obviously sea level change (i.e. rising sea level) presents a problem for defining \"sea level\", but it was a problem well before that with tides, changes in heights of tides in relation to the shape of coastlines etc. The wikipedia article on [sea level](_URL_3_) has a good discussion of this and basically various countries have defined \"sea level\" as something different and thus elevations on older maps between countries could be slightly different depending on which sea level you use.\n\nIn general, these reference values for various things are referred to as datums. So as discussed in the wiki article, the vertical datum for many maps in the UK is based on mean sea level measured in a particular place over a particular time period (i.e. the sea level was not updated, even if actual sea level went up). \n\nIn detail, mean sea level is basically a proxy for the [Geoid](_URL_0_). Most more modern, worldwide datums use a calculated geoid (from measurements of the earth's gravitational field) as the vertical datum (i.e. the zero height against which to measure elevations). For example, one of the very common systems is the [World Geodetic System](_URL_4_), the most current one being WGS84. WGS84 uses a particular version of the [EGM96](_URL_2_) geoid as its vertical datum. These vertical datums are periodically updated, but in relation to more accurate and higher resolution measurements of the earth's gravitational field, not changes in sea level height. This [article](_URL_1_) has a nice discussion of this topic as well.\n\nTL;DR - While mean sea level was the go to datum for hundreds of years, it's been supplanted by measurements of the earths gravitational field to define a precise geoid (equipotential surface) as the reference point for measuring elevations. Even when mean sea level was used, it was not constantly updated, some reference value was chosen and used for an extended period."
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"http://www.esri.com/news/arcuser/0703/geoid1of3.html",
"https://en.wikipedia.org/wiki/EGM96",
"https://en.wikipedia.org/wiki/Sea_level",
"https://en.wikipedia.org/wiki/World_Geodetic_System"
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46xidt | georgia's "religious freedom" bill | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/46xidt/eli5_georgias_religious_freedom_bill/ | {
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"When it passed through the House the main 3 points were as follows\n\n-- It cleared ministers from having to perform marriages that violated their religious beliefs; (meaning a minister that refuses to perform a LBGT marriage cannot be sued for discrimination)\n\n-- Business owners could remain closed on Saturday or Sunday if working conflicted with their religious beliefs; and\n\n-- Religious institutions did not have to rent facilities for ceremonies that violated their beliefs.\n\nThe Senate added \"prohibit discriminatory action against a person who believes, speaks, or acts in accordance with a sincerely held religious belief or moral conviction that marriage is or should be recognized as the union of one man and one woman or that sexual relations are properly reserved to such marriage.\" (meaning for example someone whose religion states that LGBT is wrong cannot be discriminated against for saying this or refusing service to LGBT people.)\n\nSince the Senate modified the bill it has to go back to the House for their vote again. "
]
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[]
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||
3ol1fy | Tuesday Trivia | Adventures in the Archives | [Previous weeks' Tuesday Trivias and the complete upcoming schedule.](_URL_0_)
It’s the most wonderful time of the year! It's October of course, the most crowded of commemorative months! And Native American History Month, British Black History Month, American LGBT History Month, and of course Vegetarian Awareness Month, are all budging up on the park bench today to make room for [American Archives Month!](_URL_1_)
So please share:
* items from archives (digital or physical) that you have discovered and the stories behind them
* tales of your archival adventures (or misadventures)
* hot archival research tips
* your most pressing archival questions that you think should go in my inbox, if you wish
* **anything you want to share about archives is welcome really**
(naturally we are not limiting ourselves to only American archives though, because that would be silly)
**Next week on Tuesday Trivia:** Starting off a blitz of user-submitted themes that will take us through the end of 2015, we’ll be celebrating history’s cleverest copycats with Remakes, Reboots, and Revivals! | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/3ol1fy/tuesday_trivia_adventures_in_the_archives/ | {
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"I've got a good one, a few years back I interned at a local archive in order to beef up my CV and get some general experience, because at this point I had none. After introducing myself and doing some light filing and genealogy work, I asked the head archivist if she had anything she wanted done but couldn't do herself. Then she showed me the basement.\n\nOver the years, the archive had been donated many hundreds of items, but couldn't do anything with them because it was an archive, not a museum. So all these artifacts and objects were moved to the many empty shelves in the basement. The archive itself was a former [jailhouse](_URL_3_) and the remaining cells were in the basement, completely loaded with stuff. My first job was cleaning this first room of the basement out, moving everything to the furthest back room, so they could turn the cell area into a mini museum. This done, I was moved to the third room where all the previous items had been moved: [bottles,](_URL_0_) [musical instruments](_URL_4_), even an old WWI [Memorial.](_URL_1_)\n\nAfter a few days of cleaning and cataloging I came across with these two old school metal garbage cans, one was full of documents and papers, the other had a bunch of junk. Except for something extremely heavy at the bottom. I pulled out the object, looked at it for a second, realized what it was and immediately got my boss. \"Ms. Gandy, will you come downstairs with me, I *need* to show you something.\" So she followed me downstairs looked at it and said \"Well, what is it?\"\n\n[An Artillery Shell,](_URL_2_) Rusted, leaking black powder and extremely unstable.\n\nI put the shell in a box and brought it upstairs (nearly dropping the thing, and becoming a stain on the wall in the process) where the archivist called the Sheriff. The Sheriff took a look at it and called SLED (State Law Enforcement Division) The SLED guy showed up and called the *Army.* When the Army finally arrived, they took a look at it and said it was *so unstable they couldn't risk carting it to their base 45 minutes away* The Army took the bomb out to the local racetrack and had to blow it up there, along with various other shotgun shells and bullets I had found in the basement of this archive. ",
"Oooh! The Australian National Library, which I love with all my heart, is sort've weird in that it has a remarkable quantity of primary evidence concerning WWII era Finland. It has a document at the moment that I'm super interested to see titled ['The Mannerheim Clique Will Answer for their Crimes!'](_URL_0_) It's an English-language Soviet propaganda pamphlet dating to November 1939, shortly after the onset of the Winter War. It's not exactly of a great deal of use for me, but I'm pretty excited to see what sort of salacious rumours the Soviets were cooking up about the Finns, particularly first hand like this! ",
"I've got sort of a general archival question I could ask.\n\nI'm currently pursuing my Masters in Library and Information Science, but hope to focus on and find a future in archives and museums rather than libraries. I worked for four years during my undergrad in the university archives and loved it, so I have some experience in the field.\n\nMy question is, are there any areas in archival study that should be focused on by a student planning on entering the field soon? Like, are there are areas of the medium that are evolving or growing, such as digital preservation? Also, any advice or tips for what I can do now to make my resume look better in the future such as volunteer opportunities and such.\n\nThanks!",
"General question to all you archivists out there:\n\nTHe digital future of archives - yay or nay? The way I hear things, the move to digitize great parts of archival collections has been faced with criticism, especially pertaining to longevity. In short, we know how long paper and microfilm lasts - do we really know how long hard drives, jpgs and pdfs will last?\n\n\nAlso, a work related complaint: I have to use the German Federal Archives frequently. This archive took over many a record from the former GDR archives in Potsdam. Mainly it is stuff pertaining to the Nazi era which the GDR archives copied from other Eastern European archives. However, some of the stuff can not be seen as a user because they say that they only give out microfilms if they have the originals and with the GDR stuff, they don't know if they have the originals because there is no concordance. This annoys me greatly.",
"While working on my undergraduate thesis I was reading the microfilmed correspondence between the figure I was studying and the US president at the time. The handwriting in some of the letters was pretty atrocious; a fact that was not helped by the ink that had bled through the thin slips of paper used in this particular exchange.\n\nI was casually sitting with a friend in my living room, casually chatting about how our respective theses were doing, when I decided to ask his help deciphering this one particular section of the letter that was particularly maddening.\n\nI'm at the part where they're discussing where they met. Ten minutes in we figured it out: \"in the garden of the Bishop\". Our blood went cold for a second. THE Bishop? These were spies having a rendezvous in the garden of one of the best known figures from that period? No evidence that the Bishop knew, but it was still a 'holy crap' kind of moment for me.",
"I've never been in an actual physical archive. Theoretically, I can visit an archive on campus (it holds a number of Theodore Geisel's manuscripts, which does go on display every so often), but I'm an undergraduate student and I don't really have an excuse to go other than \"uh, I work at access operations\". So instead, I spend a lot of time going through the digital archive of the Jonestown Institute. \n\nBasically, if you've seen a lot of my posts about Jonestown, a certain domain comes up every single time: \"_URL_0_\" This is the location of the website \"Alternate Considerations of Jonestown and Peoples Temple\", run by the Jonestown Institute at San Diego State University. Besides hosting articles and commentary from *the jonestown report* (a physical journal that ended in 2013, IIRC, and is now completely online), it contains large amounts of primary source material: tapes found in Jonestown and released by the FBI through Freedom of Information and Privacy Acts, Peoples Temple files, telegrams between various government agencies post-November 18, letters from relatives, newspaper articles, Peoples Temple publications, \"thank you Dad\" letters, the Edith Roller journals, poems from Jonestown residents, articles of corporation, etc. Most of these are online and available to the public *for free*. Some of the stuff does need to be ordered for a nominal fee (namely, a large number of tapes recovered from Jonestown have not been converted to MP3s, and thus you need to email them to order the tapes themselves), but otherwise the average reader can go through the material and read them/download them/etc to their heart's content.\n\nI guess I could tell a story about stuff I've found, but I don't have time to do that today. Too much work. ",
"So I decided, in Pretoria, to go into the old Surveyor-General's kelder and check out the \"ou-nommerleêrs\" and \"ou-plaasdiagramme,\" which turned out to be quite an adventure before the removal of the office to a more modern building. It had been there for nearly a century, and so things were just sitting on shelves, partial series, some really valuable things next to some bug-eaten dross. A few things were damaged from a fire (well, from the water) in the 1960s, but most of it was intact aside from the dust and old smoke that settled on everything. But the most amazing part had to be the rolled plan \"storage.\" I noticed a closed door behind a shelving rack, and decided to see what was inside. Sure enough, what was there was about 2.5 meters of stacked roll plans dating from all over the calendar and situated all over the province, a bunch of old mining claims, and it was precarious. The only way to get in was to climb up it and start excavating. This was possibly the most dangerous thing I've done in an archival building because it was really unstable, and I did ride the plans down when one side finally gave way.\n\n[But what good is this description without a picture? Here's the thousand words, after I'd sort of restored order because I didn't want to be known as the researcher who wrecked everything.](_URL_0_)\n\nThis was easily the best-lit area of the whole kelder, with a whole fluorescent tube for it. The rest of the basement aside from the files and books was creepily full of old furniture, not an electric outlet in sight, and a grand total of three fluoro tubes to light an area about 10m by 70m in size. Yeah, I bought a flashlight. The kicker was that in the plan-surfing event room, I found nothing of actual use. It was all on the racks around the corner shrouded in the darkness of the oubliette. Good times, good times.",
"One of the interesting experiences I've had over the years was getting a backroom tour at the Academy of Natural Sciences in Philadelphia, some years ago before it was part of Drexel University. \n\nOne of the more interesting artifacts they had was several *massive* cabinets labelled as \"Thomas Jefferson Collection\". It turns out that Thomas Jefferson had quite a fossil collection, much of it from Big Bone Lick in what is now Kentucky. The also had a couple of the original labels, hand-written by none other than William Clark in 1807. These fossils included an enormous mastodon skull that probably weighed at least 200 pounds. (I may even have some pictures of this. I'll see if I can find them.)\n\nJefferson apparently had asked Louis and Clark to keep and eye out for any living mastodons might find while crossing the great plains. Given Jefferson's well-documented predilection for massive animals (the moose AMA a few months back), and that the existing mastodon fossils were recognized as being similar to those of elephants, which occur in Africa and Asia, this request to look for live mastodons was not anywhere as ill-informed as it sounds to us today. The American continent was full of strange critters (Moose! Mule-deer! Rattlesnakes! Bison!) and it was fully acknowledged by educated people that the organisms of the New World were often more similar to their Asian relatives than to their European affiliates (Fir trees are a good example).\n\nI think they upgraded the collection storage sometime back in 2002 and no longer allow grubby-thumbed teenagers to rifle through their collections of irreplaceable artifacts. "
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c9vsg6 | why is it preferable for an airplane to have the propeller pulling at the front, instead of pushing from the back? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/c9vsg6/eli5why_is_it_preferable_for_an_airplane_to_have/ | {
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"They airflow from the propeller at the front creates more lift as it transfer across the fuselage. It also helps the vertical stabilizer.",
"Generally propeller placement actually comes down to engine placement.\n\nYou need the center of mass of a plane to be in front of the center of lift otherwise the nose of the plane will constantly be lifting up and trying to stall you out. This generally calls for the big heavy engines to be in front of the wing.\n\nThere are a bunch of designs that have made it work, from little ones like the [Saab J21 fighter](_URL_1_) to bigger ones like the [Convair B-36 Peacemaker strategic bomber with 6 engines](_URL_0_), but it adds a fair bit of complexity to the design, and complexity generally equals weight, and weight is something you're trying really hard to avoid\n\nOther downsides for it are that the prop wash actually helps generate more lift on a propeller plane as you're shoving fast air across the wings, and having the prop blow air across the engine helps keep it cool and reduces the risk of engine fires. If your prop is behind then wing then the wing goes through the air before the prop can causes turbulence which reduces the propeller efficiency by a few percent as well which requires a stronger(aka heavier) engine than if it were in front.",
"The dirty air from the propellor wash over the wings does not increase lift (actually its likely to decrease lift), and cooling is not an issue in modern aircraft engines. The main reasons are stability and access to undisturbed air at the front of the aircraft.\n\nFor stability, think of pulling vs pushing a shopping cart while running. Both are fine in a straight line, but as soon as you hit a rough surface or turn, pushing will be much harder to control, as you have to work to correct the random imbalances. Pulling, either the shopping cart or the aircraft, is much more self correcting. Its called a stable vs. unstable equilibrium. In an unstable equilibrium like pushing from behind a cart or a rear mounted propellor, small unwanted influences like bumps in the ground or pockets of differences in air density will be much harder to compensate for. \nSome planes, especially fighter jets, are designed to be in unstable equilibrium for increased maneuvering performance, but mistakes are much more unforgiving and a computer running a controls algorithm is often absolutely needed to maintain control. Civilian or less performance oriented transport aircraft don‘t need that level of maneuverability and thus stability is prioritized. \n\nAlso, at the front of the aircraft, the propellor has direct access to the freestream, undisturbed air, meaning its performance is more constant and predictable. Put it behind a wing, and go into a steep dive or climb, and suddenly only half the propellor is experiencing remotely freestream air.\n\nEdit: there‘s a reason why the examples in the other comment are pictures in black and white. Before we had computers, not as much of this was known or could be tested, so aircraft design was pretty monumentally terrible compared to anything designed with the help of a computer."
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3v1li4 | Why did Japan join the Axis during World War II | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/3v1li4/why_did_japan_join_the_axis_during_world_war_ii/ | {
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"Hi, I discuss the details of Japan's joining of the Axis alliance [here](_URL_0_)."
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3qm48s | nitrogen fixation | I've read a lot about it but my teacher did a crappy job of talking about it in class, anyone have any help? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3qm48s/eli5_nitrogen_fixation/ | {
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"Basically, nitrogen is really, **really** important for living organisms. Unfortunately, most of the nitrogen on Earth is in the atmosphere in the form of N2 and most creatures lack the tools to break it apart and make use of it. \n\nFortunately, there are bacteria that *do* have the tools to do so. They are able to convert nitrogen forms like ammonium (NH4) which can be used by other creatures.",
"Nitrogen is used in many many biological processes. However, even though there is more nitrogen in the air than oxygen, the nitrogen in the air is useless due to the triple bond holding the N2 molecules together being very very strong. Many organisms cannot use this nitrogen, but fortunately there are some plants and bacteria which can convert that nitrogen in the air into a more useful form of nitrogen, and fix it into the ground, so that other plants can get that nitrogen, then animals that eat the plants get that nitrogen, and so on."
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16hj0z | What does it mean when we say there may be more dimensions but they are too 'small' or 'curled up' for us to see? | I just can't get my mind around what these terms mean. What does 'small' or 'curled' mean for other dimensions beyond the three we're used to? How can a dimension be bigger/smaller/shaped different than others? Isn't it like saying the dimension of 'depth' is smaller than 'length'? What would having 'depth' be small (but just big enough to see) and curled up look like to a predominantly two dimensional creature? | askscience | http://www.reddit.com/r/askscience/comments/16hj0z/what_does_it_mean_when_we_say_there_may_be_more/ | {
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"Imagine an infinitely long cylinder. If we contract the radius to a very small distance, then it would appear, to a macroscopic observer, that this was a one dimensional line. But on a very small scale, one would note that the surface of this cylinder had two dimensions - one which is very large and stretches along the length of the cylinder, and one very small which wraps around the circumference.",
"Is this explanation by Steve Green makes it clearer to you: _URL_0_\nStart at 6:40 if you don't want to see the entire thing",
"Think about a cylinder, it has two dimensions. Imagine a \"fat\" cylinder like a barrel, locally it might seem like a normal, flat plane, similar to the way the surface of the Earth seems flat even though it's curved. Now imagine that the radius of the cylinder shrinks until it is incredibly tiny, smaller than an atom. Now the cylinder seems like a line, only 1-dimensional, even though it is 2-dimensional. The other dimension is \"curled up\". Or, imagine a torus (donut) that is similarly narrow, like a loop of string. Eventually it starts to look like a circle, also 1-dimensional.\n\nNow imagine the 3-dimensional analog of a cylinder. You can move left and right or back and forward like normal, and you can move up and down as well. However, you find that up and down wraps around. When you go up you eventually get back to where you where before, and the same when you go down. So, 3-dimensional but one dimension is finite and connected back on itself. Now imagine that the up/down dimension is tiny. Let's say it's only 1mm thick, for example. Well, now we still have a 3-dimensional space, but it's very constrained along one of them. But what if it's even smaller? Smaller than the size of an atom, smaller than the size of a proton even, much smaller. Now we have effectively a 2-dimensional world. It would be impossible for someone living in such a world to perceive the up/down dimension, because it would be so small. If two particles are at different positions in the squashed 3rd dimension then they would be a slightly different distance apart than if the two particles were in the same position in that 3rd dimension. However, because the squashed dimension is so small this difference is inconsequential, and affects things like the strength of forces between the two particles too little to be measured.\n\nYou can do the same thing, but in ways that are more difficult to visualize, with an arbitrary number of dimensions. So our 4-dimensions (3 of space + 1 of time) could actually be accompanied by other dimensions, but those dimensions would be so small that we wouldn't be able to perceive them. Which may be the way our universe works, but so far there is no observational evidence for it.",
"Say you're in space. Look forward. You see impossible vastness and so on. Technically, you could loop around it Magellan style, but it's so large that's inconceivable. Look up, same thing. Look left, same thing. Now look **HYPERLEFT!** You can't; not because it's incomprehensible, but because the entire universe won't fit your head in it in that direction.\n\nRemember the actual meaning of a dimension is a number you use to identify a location. You can treat the surface of the earth as two-dimensional, because you need two numbers, latitude and longitude, to say where you are. The 3rd dimension is altitude, that is, distance from the center of the earth, which you can ignore some of the time.\n\nBut if the surface of a perfectly smooth sphere were a self-contained universe, you could ignore \"altitude\" all the time, because every single particle in that universe would have the same altitude. If you floated above the surface of that universe, and watched the little circle guys run around on it, they could look 'north' by putting their lenses 'north' of their retinas, they could look 'east' by putting their lenses 'east' of their retinas, but they couldn't look at you because they couldn't put any part of themselves 'above' or 'below' another.\n\nNow imagine the sphere is a circle. We've added a dimension, in that you're now you're two dimensions ahead of that universe. It's a 1D universe, the dimension being how many degrees around the circle you are. But now zoom in really close to the universe. What you thought was a line is actually a tube; the circle is actually a torus, a donut shape. Now there are actually two dimensions in that universe. If you go 'north', you go around the cross section of the tube, and get beck where you started very quickly. If you go 'east', you go around the whole thing, and it takes forever to get back to where you started.\n\nBut the width of the tube is so small that you can't really occupy two different places on it. It's very much like the third dimension in the sphere universe. Everything is the same part of the tube, because the different parts of the tube are so close together that two protons in a nucleus can't even comfortably occupy the 'north' and 'south' ends of the tube at the same time, they have to sit side-by-side, 'east' and 'west' of each other.\n\n**Basically, the dimensions as ideas are all the same; it's that the universe is really short *in* those dimensions.**"
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3chhdg | why do some plants have red leaves instead of green? do they get less energy from sunlight? | Here are some examples.
_URL_0_ | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3chhdg/eli5_why_do_some_plants_have_red_leaves_instead/ | {
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"The colour green comes from a molecule called chlorophyll in plant cells. I believe chlorophyll can come in different types, that capture different wavelengths of sunlight. In most plants, all wavelengths except for green are absorbed, so green is reflected back. That's why they appear as green. \n\nDuring the fall, the chlorophyll can degrade and/or change, and as such, the red-orange-yellow wavelengths of light are reflected back at us, giving the leaves those colours \n\nThe flowers and plants you link to either change colours for similar reasons. Basically, the pigment they contain in the cells predominantly absorbs different wavelengths than traditional green plants, and so reflects a different colour. "
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2q9ito | what *is* the space that gets taken up when i add "data" to my hard drive, phone, memory card, ect., and how exactly does it work? | I really don't know how to properly explain, but when I add, say, music to my phone, what exactly happens that limits the phones capacity? The phone doesn't gain any weight, and nothing actually goes inside it. There is no physical "empty space" inside of a storage device, correct? What is causing the phone to just "not process" the data? And what does data even look like? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2q9ito/eli5_what_is_the_space_that_gets_taken_up_when_i/ | {
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"Data is stored by a specific arrangement of the physical components of the drive. For example, in a standard HDD, the data is stored as the directions of magnetic fields on billions of different locations on a coated metal platter. The surface of the platter is always magnetized, and depending on how the magnetic fields are arranged, it can represent any file that has as many bits as there are individual \"sections\" of the hard drive's surface that can be reliably magnetized (as well as some arrangements being used to mean \"no data\").\n\nSolid state storage (SSD) uses individual memory cells made out of transistors for each bit, instead. In that case, the capacity of the drive is determined by how many physical cells it has, and the data is stored as electric charge in the transistors.\n\n > And what does data even look like?\n\nNothing. At least, not by itself. Data isn't a \"thing\". It's an *arrangement of other things*. For example, imagine that you have a row of light switches that aren't connected to anything. They're just kind of *there* on the wall, and you can flip them up and down if you want.\n\nSo let's say that you have four of those switches, and you flip them like so:\n\nup, down, up, up\n\nYou can treat downs as the number 0, and ups as the number 1, so your light switches indicate:\n\n1011\n\nThat's the binary representation of the number eleven. So the \"data\" for the number eleven looks like light switches when you're using light switches to store the data. Likewise, in an HDD, data for the number eleven might \"look like\" magnetic fields arranged south, north, south, south.\n\nIn short, \"data\" is just \"using the state of some sort of system to represent information\".",
"Think of the storage as being lots and lots of switches.\n\nWhen your phone is empty, the position of these switches - whether they are on or off - really doesn't matter.\n\nWhen your phone is full, the switches are all being used to represent the photos, apps and and music in your phone. You can't install more apps, because there are no free switches to move into the right position to represent your new app.\n\nSome of the switches are used simply to keep track of what the other switches are being used for, as well as keeping track of which switches are free for use."
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33t899 | what causes rivers to suddenly be rapid in certain areas? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/33t899/eli5_what_causes_rivers_to_suddenly_be_rapid_in/ | {
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"The speed of a river is determined by a lot of factors - the steepness of the ground it's flowing down, how deep the water is, and how wide, mostly. If those change suddenly, the speed of the river can change suddenly too.",
"Think of a river like a garden hose. The water flows smoothly and at a certain speed if the end is open. But putting a sprayer (or your thumb) over the end gives the same amount of water less area to get through, increasing its pressure, speed, and turbulence.\n\nThat's what happens when rivers get suddenly shallower or narrower, or both. The old saying \"still waters run deep\" kind of captures this phenomenon as well."
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l7qm6 | What's the point of SATA 6 GB/sec? | Most drives can't even get 1 GB/sec read/write performance. When we can't even use all of the 3 GB/sec that has been the standard SATA connection, what's the point of having 6 GB/sec SATA connections?
Thanks | askscience | http://www.reddit.com/r/askscience/comments/l7qm6/whats_the_point_of_sata_6_gbsec/ | {
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"Prolly belongs elsewhere, but the point of having that is that it probably costs very little extra to include(or may even be cheaper, depending on if anyone even bothers making the slower stuff), and there are undoubtedly some applications that can utilize it, stuff doing some extreme data crunching or the like.",
"First, just in case you didn't know, those are bits per second, and SATA uses a 10/8 encoding which means that the 1.5 Gbit/s SATA-1 rate equals 150 MByte/s, the 3 GBit/s SATA-2 rate equals 300 MByte/s, and 6 GBit/s SATA-3 rate equals 600 MByte/s.\n\nSecondly, there are SSD drives on the market today that can read and write much higher than 300 MByte/s, which means they would be bottlenecked in a SATA-2 system. The current fastest drives can achieve 500-550 MB/s, which means they can nearly saturate the full speed of SATA-3, making it very much a necessity.",
"Prolly belongs elsewhere, but the point of having that is that it probably costs very little extra to include(or may even be cheaper, depending on if anyone even bothers making the slower stuff), and there are undoubtedly some applications that can utilize it, stuff doing some extreme data crunching or the like.",
"First, just in case you didn't know, those are bits per second, and SATA uses a 10/8 encoding which means that the 1.5 Gbit/s SATA-1 rate equals 150 MByte/s, the 3 GBit/s SATA-2 rate equals 300 MByte/s, and 6 GBit/s SATA-3 rate equals 600 MByte/s.\n\nSecondly, there are SSD drives on the market today that can read and write much higher than 300 MByte/s, which means they would be bottlenecked in a SATA-2 system. The current fastest drives can achieve 500-550 MB/s, which means they can nearly saturate the full speed of SATA-3, making it very much a necessity."
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4e47f3 | how is it profitable for wineries to sell their wine cheaply enough to an import/export company that i can get it on another continent for $5.70/bottle? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4e47f3/eli5_how_is_it_profitable_for_wineries_to_sell/ | {
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"There is a world wide surplus of basic grade grape wine juice. Australia, Chile, Argentina, US all produce commodity grade grape wine juice.. Perhaps you've heard of [Charles Shaw](_URL_0_), aka Two Buck Chuck. A few years ago it was about $2 at the retail level, wholesale perhaps a dollar or less. Obviously those wines aren't made with grapes from premium areas such as California's Napa and Sonoma valley. \n\nLow grade wines don't have to have the attention to consistent flavor profiles or duration of aging that mid grade and premium wines do. A few dozen 275 or 330 gallon IBC totes is enough to fill a stainless fermenting vat, and produce several thousand 750mL bottles that are capped with inexpensive screw tops, or synthetic corks. Load it into a shipping crate, and off it goes around the world. \n\nI bet most of that $6 is middleman markup and transportation costs.\n\n"
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aanq1o | what spurred the usage of 'xmas' in place of 'christmas'? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/aanq1o/eli5_what_spurred_the_usage_of_xmas_in_place_of/ | {
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"\"X\" is the Greek Letter Chi, which is the first letter of \"Christ\" when written in Greek. The X is just an abbreviation, and was used for many years by Christians as a secret code that only others would know to show they are Christian in times when it wasn't best to be open about it. ",
"**Please read this entire message**\n\n---\n\nYour submission has been removed for the following reason(s):\n\n* ELI5 requires that you search before posting.\n\nThere are absolutely no exceptions to this rule. Please see this [wiki entry](_URL_0_) for more details (Rule 7).\n\n\n\n---\nIf you would like this removal reviewed, please read the [detailed rules](_URL_2_) first. If you still feel the removal should be reviewed, please [message the moderators.](_URL_1_?)"
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2nxyc5 | how do vegetables get vitamins and minerals if they only "eat" water and sunlight? | Where does it all come from? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2nxyc5/eli5_how_do_vegetables_get_vitamins_and_minerals/ | {
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"They also take in nutrients from the dirt. That's how you can get things like iron etc. ",
"In order to make sugars, a plant needs certain elements in its diet. It gets Carbon from the Carbon Dioxide in the air. It gets H2O from water. When it transfers in the water, it uses a tube in its stem, called the xylem. When this absorbs water from the soil below it, it carries nutrients in the soil occasionally, giving the organism certain vitamins and minerals. Of course, some plants will adapt to this, giving them a dependency or a new feeding pattern where they can mature faster with minerals.",
"They do eat other stuff than water from the dirt. Phosphorus and stuff."
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6ql1zc | what gives fire its shape? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6ql1zc/eli5_what_gives_fire_its_shape/ | {
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"When air is heated, it tends to expand.\n\nTo explain why it expands - Heat is basically the measure of vibration and movement of the actual molecules within a substance. When something is solid, these vibrations don't have enough energy to stop the attractive forces between the molecules thus they stay mostly in place.\n\nWhen something is a liquid, the molecules have enough energy to repel a LITTLE bit from the attracting forces, but can at least move so they tend to slide over one another and create something that flows - A liquid.\n\nSomething that is a gas has enough energy for each molecule that they have completely freed themselves from one another, and will expand to fill any container that they are in because they are basically just constantly slamming into one another as they move. This is what causes pressure because the molecules are constantly bouncing off of one another and forcing each other away, and WANT to move outward.\n\nThe hotter something is, the more it wants to expand as the movement of the molecules increase. Thus the lower density it would have as it expands.\n\nThis expansion lowers the density of the air that is being heated by the flame, as such it wants to rise upward because the cold air around it is more dense and forcing the hot air upward. Hot Air balloons work on this idea. \n\nSo in essence what you are seeing is not the exact shape of the fire, but what the air that is moving upward forms it into.\n\nIn space, fire would be much more stable in its shape and be mostly rounded as there is no gravity for hot/cold air to convect against.\n\n"
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fh6hi | What could be the drawbacks of immortality? | I can't find the article. But about a year or two ago, I remember reading something on reddit about scientists "discovering" the fountain of youth... that it is possible for humans to live for hundreds or even thousands of years. When this happens, what do you think will happen to us? | askscience | http://www.reddit.com/r/askscience/comments/fh6hi/what_could_be_the_drawbacks_of_immortality/ | {
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"Read a book called \"The Boat of a Million Years\" by Poul Anderson.",
"From a population dynamics point of view, having too many of one species (which is what longevity would do) would eventually collapse due to a lack of resources to sustain that population.",
"The people you don't like being immortal.\r\n\r\nSeriously though, the only drawback to immortality I can think of is a Tragedy of the Commons. Being immortal would be great but everyone being immortal would lead to resource depletion really quick.",
"Can entropy be reversed?",
"I just want to point out that the 'fountain of youth' has *not* been discovered, and there is currently no possibility of extending life to hundreds of years. ",
"Your memory would run out after not very long. Unless you had some kind of memory upgrade you would no doubt, before too long, not be able to remember most of your life.\n\nNot something often considered by people who make up long lived or immortal characters.",
"I don't know, but I'd be willing to dedicate hundreds of years to research finding out.",
"Having to live forever.",
"In some ways, I fear the older generation that won't let things change. I mean, can you imagine arguing slavery with someone from the 1600's? Would we be fighting laws on witchcraft? Perhaps I will become a decrepit denouncer of the future, but if so, I hope I will die off to make way for new ideas."
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1d651z | how do free softwares like vlc player make any money? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1d651z/eli5_how_do_free_softwares_like_vlc_player_make/ | {
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"Broadly speaking, they don't, but that's okay because they aren't trying to. VLC is \"community-developed\" software; it's just a bunch of people who got together to write a video player because they wanted to.",
"Maybe not VLC specifically, but a lot of them are side projects. Get the producer's namde out there with a free product, and maybe the consumer will look into their paid products",
"Some have a community of developers donate their time, others sell support service for their software etc. \n\nRedHat makes a linux distribution, but also teaches training for a healthy sum. I'm sure they have other services too.",
"Imagine, if you can, for a moment a world in which people's first thought is not 'how can I make money out of this?' but is instead, 'how can I make the world a better place?'"
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85olxj | how do air brakes work? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/85olxj/eli5_how_do_air_brakes_work/ | {
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"The air is applied to a large gasket that pushes on an acutator rod. That in turn pushes a lever attached to a rod that goes into the brake drum, the rod has a double ended cam shaped like an S that forces the brake shoes into the drum",
"They are not that much different than regular brakes.\n\nReguar brakes use hydraulic fluid. You push the brake pedel, and your master cylinder forces fluid down the brake line, and that squeezes the brake pads against the rotor.\n\nAir brakes are the same thing. You have a compressed air tank, and when you press the brake, air pressure is forced down a brake line which forces the brake pads against the rotor. \n\nAir brakes can also work the exact opposite way. In a train, the air will keep the brakes open. A reduction in pressure is used to apply the brakes. This has the advantage that if a train car was disconnected or there was a loss of air pressure, the train car or train would come to a stop. It should prevent a runaway train.",
"Air brakes are essentially regular drum brakes on steroids. Disclaimer: I’m an auto insurance adjuster, not a mechanic or engineer. I know the systems; you may not get the perfect technical language but I’ll probably describe them in simpler language. The way a drum brake works is like this:\n\nImagine that you have a cup, like a regular cup for drinking. Stick your hand into that cup, but not enough that you can’t turn it. Now imagine that cup is spinning quickly and your hand is just hanging out in there not really creating any friction with the inside walls of it. Now imagine that you form a fist with your hand and the friction between your expanded fist with the inside of the spinning cup causes it to stop spinning. \n\nIn this analogy the cup is the Brake Drum. Your hand is the Brake Shoes, and the actual skin on your hand that makes contact is the Brake Lining. In a drum brake system the Shoes and Linings are two horizontally opposed plates that remain stationary attached to a backing plate, while the Brake drum they’re inside of spins with the wheel. The Shoes and Linings don’t contact the Drum because a Return Spring keeps them tight. When you press the brake pedal, brake fluid travels through the brake lines, though the Master Cylinder and Power Booster, where it becomes pressurized, and enters a Wheel Cylinder (piston) between the Shoes and Linings, that pushes them out. They make contact with the Drum, like that fist in that cup, and that friction stops the vehicle. \n\nNow, the stopping mechanisms on an Air Brake system are generally the same with a few exceptions. Instead of hydraulic brake fluid, pressurized air is used. This is achieved much in the same way that an A/C systems work: a compressor, series of lines, and receiver-dehydrator to keep it all dry. Instead of a wheel cylinder (piston) pushing the Shoes and Linings against the Drum, a push rod activates a lever attached to a cam, which pushes the Linings out. The Cam looks like that meteorologist symbol for a hurricane, it just sits in there and turns when activated, pushing out the brake Shoes and lining against the Drum, like your hand in that cup."
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2av1ki | how does 'immigration reform" aka legalizing 11 million people and allowing for more foreign workers help create more jobs? | Bills Gates is laying off thousands of American workers yet at the same time says that we need to bring in more foreign workers. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2av1ki/eli5_how_does_immigration_reform_aka_legalizing/ | {
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"As far as I know, it doesn't. The only thing it will do is further depress wages. Simple supply and demand. \n",
"Im not sure how it creates more jobs but it should create more revenue. Undocumented individuals often CANT pay taxes because they cannot get a social security number nor a Taxayer ID number. The people who they propose legalizing are not people who just came here but those who have been here a long time and are already part of the economy. When Regan legalized immigrants they had to prove that they had been residing in the U.S. since 1981 i believe. No one is proposing opening the border to new immigrants. ",
"None of these answers are ELI5 so I will try to make one. It is all about supply and demand. Company's in USA need high skill workers and currently there is a shortage of skilled workers. They hope to attract more skilled and educated foreign workers which takes less time and money than training or educating your current workforce . At the same time there is an excess of so called unskilled workers in America who are competing for the few available jobs. Therefore American company's can be very picky in hiring and employing unskilled laborers, since there is such a large supply of them, so company's lay off workers who are not performing to their standards. "
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8z90gy | How do Galaxies Accelerate? | I apologize if this is not flaired properly.
I was having a discussion with someone about the speeds that galaxies accelerate at. He was saying that in order to calculate the velocity of a galaxy, it would be as easy as using distance over time.
I fervently disagreed. I said that at the order of magnitude of a galaxy, moving from Point A to Point B is not that simple. Time will be affected by the gravitational field around the galaxy. Additionally, at this size, spacetime is moving itself. So deciding a point is not so simple.
Was what I said anywhere close to the truth? | askscience | https://www.reddit.com/r/askscience/comments/8z90gy/how_do_galaxies_accelerate/ | {
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"You don't need to worry about time dilation too much - the gravity fields and velocities are almost always weak enough and slow enough that it doesn't make much difference.\n\nYou do need to worry about the expansion of spacetime if you're working on large distances. Space is expanding everywhere at a rate of about 65 km/s per megaparsec (a megaparsec is about 3 million light years). That is, for every megaparsec of distance between two galaxies, the space in between them is expanding at about 65 km/s. So if you are separated by two megaparsecs, the space in between the galaxies is expanding at about 130 km/s.\n\nThis is not how \"normal\" speed works - \"normal\" speed is independent of distance. This isn't really a \"speed\" at all, although it uses the same units. You can even have rate of expansion be greater than the speed of light, which is not possible for \"speed\".\n\nSo you're right that you can't just take the rate of change of distance over time and think of that as a normal classical velocity - except for galaxies that are so close to us that the \"normal\" speeds dominate over the expansion of the universe. For example, when galaxies are colliding with each other, we don't need to worry about all this spacetime stuff and we can just think of velocities in the classical sense without much error."
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xisdd | what causes the static screen when you go to a nonexistent channel on your tv. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/xisdd/eli5_what_causes_the_static_screen_when_you_go_to/ | {
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"It's just noise in the electronics.\n\nIn old televisions, where you were capturing things with an antenna and adjusting with a dial, a small portion of the static at night was caused by the cosmic microwave background radiation.\n\nNumerous other more local sources contribute most of the noise."
]
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||
523jfq | how do returns work at retail stores? what does the store do with broken returns? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/523jfq/eli5_how_do_returns_work_at_retail_stores_what/ | {
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"I used to work at Best Buy. When we get a return, it goes into something called functionality check where someone checks the device for accessories or any damage/defects. If it's good, they mark it \"open box\" at a discount. If it's broken, they send it out to their service center to be repaired and then resold in the same fashion. If it's beyond economical value to repair, they send to \"PRC\" or Product Return Center which is sending back to the manufacturer for a small kickback so it's not a total loss. "
]
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||
2svgs6 | How do computers calculate limits, derivatives, and integrals? | Would it make sense to implement our human tricks (power rule, chain rule) into an algorithm, or is it always done through brute force? | askscience | http://www.reddit.com/r/askscience/comments/2svgs6/how_do_computers_calculate_limits_derivatives_and/ | {
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"tl;dr: not really. CAS's sometimes use them, but that's not really what you're asking I think.\n\nThere are two types of systems you could be dealing with here. \n\nFirst, using numerical methods on a computer to take a definite integral, derivative at a point, etc, generally use an array of numerical techniques. For example, there are a lot of different methods to approximating a definite integral - one of the most commonly used ones is [Simpson's Rule](_URL_2_), which approximates the area under a curve as several segments of parabolas. For example, in Numpy, a commonly used scientific package for Python, the numpy.quad() method for numerical integration uses a variant of this rule to calculate the value of the integral. There are several other methods for [numerical differentiation](_URL_0_) and taking limits, but none of them really use a commonly used \"trick\" such as the chain rule, integration by parts, etc., since there is no need to.\n\n[Computer algebra systems](_URL_1_), such as some functions of Mathematica, allow for symbolic manipulation of variables, such as d/dx(sin(x))=cos(x). Directly copied from the above link, a list of commonly used algorithms for symbolic manipulation is:\n\n* Symbolic integration via e.g. Risch algorithm\n* Hypergeometric summation via e.g. Gosper's algorithm\n* Limit computation via e.g. Gruntz's algorithm\n* Polynomial factorization via e.g., over finite fields, Berlekamp's algorithm or Cantor–Zassenhaus algorithm.\n* Greatest common divisor via e.g. Euclidean algorithm\n* Gaussian elimination\n* Gröbner basis via e.g. Buchberger's algorithm; generalization of Euclidean algorithm and Gaussian elimination\n* Padé approximant\n* Schwartz–Zippel lemma and testing polynomial identities\n* Chinese remainder theorem\n* Diophantine equations\n* Quantifier elimination over real numbers via e.g. Tarski's method/Cylindrical algebraic decomposition\n* Landau's algorithm\n* Derivatives of elementary and special functions. (e.g. See Incomplete Gamma function.)\n* Cylindrical algebraic decomposition\n\nThese are a fundamentally different approach to evaluating a problem. However, these cannot be applied to all functions. For example, trying to integrate e^(-x^2) won't yield a symbolic result. (Actually this isn't entirely correct, the generalized \"error function\" is defined as this integral, which is what Mathematica will give you, but its values come from numerical evaluation of this integral.)"
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1lui69 | Did the Soviets create any movies about the horrifying prospect of nuclear war between themselves and the USA? | i.e. is there a Soviet 'equivalent' of Dr. Stangelove, Failsafe, etc. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1lui69/did_the_soviets_create_any_movies_about_the/ | {
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"[\"Dead Man's Letters,\"](_URL_0_), from 1986, seems to fit the bill. "
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|
ngrka | Can honey be used as an antibiotic? I've read a few articles claiming that it has the ability to help psoriasis, various skin conditions, cuts, insect bites, etc. I'm looking for some hard evidence, as the articles I'm finding on the net seem to be biased. | askscience | http://www.reddit.com/r/askscience/comments/ngrka/can_honey_be_used_as_an_antibiotic_ive_read_a_few/ | {
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"While honey has some compounds in it with antibiotic properties, they aren't at a high enough concentration to really do anything for you at the level you would need if you were trying to treat an infection. Part of why we look for novel antimicrobials in unusual places isn't so we can then use that source as our source for the antimicrobial, but so that we can hopefully figure out how to make that compound in a lab, and if it's medically effective, produce it in quantities that would be needed so it could be medically useful.",
"While honey has some compounds in it with antibiotic properties, they aren't at a high enough concentration to really do anything for you at the level you would need if you were trying to treat an infection. Part of why we look for novel antimicrobials in unusual places isn't so we can then use that source as our source for the antimicrobial, but so that we can hopefully figure out how to make that compound in a lab, and if it's medically effective, produce it in quantities that would be needed so it could be medically useful."
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dn3swo | how do podcasts make any money on advertising when their ads are just commercials for other podcasts? | I listen to a few podcasts from the iHeartRadio network and HowStuffWorks network. During ad breaks, most of the time it's just an ad for another podcast. Does the parent company just find these podcasts to bring up the amount of listeners and then eventually put ads for products and services? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/dn3swo/eli5_how_do_podcasts_make_any_money_on/ | {
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"They also advertise other things that cost money, like Audible books, mattresses, website hosting/design, etc.",
"Casper, Hello Fresh, Blue Apron, _URL_0_, Audible... just to name a few things I've heard ads for on podcasts. It's probably just the specific podcasts you decided to listen to.",
"Less popular podcasts advertise on podcasts. These podcasts know that you listen to podcasts. Much like advertising movies in the lobby of movie theaters.",
"So these are networks so they make the most money when all their podcasts are making money. So for iHeartRadio you have a super sized podcast like SYSK and while they can make a ton of money just doing ads on that if they can get you listening to three or four of their podcasts instead of just one now reach week they are tripling their money off of you. \n\nGetting one long time listener to a new podcast (a fairly easy feat in comparison to someone buying a new mattress) is way more value per impression than the core of people who buy mattresses."
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ecjj6i | with the release of last christmas in 4k, how are old music videos that are so low in resolution remastered in 4k? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ecjj6i/eli5_with_the_release_of_last_christmas_in_4k_how/ | {
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"The original was shot in very high quality to physical film (35mm probably) and then was compressed for the media standards and capabilities of the day.\n\nThey just get the original footage and compress to 4k instead of whatever the first release was. They may haved digitally altered the colours to make it more saturated etc"
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6g1ufa | the difference between architects and engineers in the design of a project, and how they work together | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6g1ufa/eli5_the_difference_between_architects_and/ | {
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"In as simple terms as possible, the architect comes up with the design of the building/area/whatever itself, and engineers figure out how to make the design work as closely to what the architect wants. They go back and forth about what is and isn't possible, costs, etc to come up with the final plan.\n\nIn short:\n\nArchitect \"I designed this, can we build it?\"\n\nEngineer, \"Yes, but it would triple the budget. We could change this slightly to make the cost better\"\n\nA, \"Hmm, that takes away from the original design i was hoping, what about this?\"\n\nE, \"Yeah we can work with that\"\n\nEtc, more back and forth.",
"Architects work on the overall design of the building. What surface each room need to be able to fulfil the need of the client, how these room need to be located in the building, etc. They also design the exterior and are responsible to respect the code (aka exit, size, number of toilet, that kind of things). They are also responsible for the building envelop, meaning what protect the building interior for the outside (insulation, walls, windows, etc) and finally they are responsible for the interior (doors, paint, etc), they may or may not work with an interior designer for that last one.\n\nEngineer work on structural integrity. Basically, they look at the design of the architect and make it work. They get information on the composition of strength of the soil and find solution to make the building that the architect stay up. They will calculate how much weight and stress will apply to the building and design the strength of material needed to make it work.\n\nHow they work together will depend on the type of building. For the vast majority of building, they don't have that much interaction. The architect work with the client to find what he need and create a coordination drawings. The engineer will look at the drawings and design a structure and emit coordination drawings. If there is something that doesn't work with the design of the architect he discuss with him to find a solution (change the design or change the structure). Usually by e-mail, in person if there is too many problems. For bigger project there will be regular meetings during the conception.\n\nBut from time to time, the architect will want to make a non standard building. For example a stadium, a skyscraper, a large building in wood, etc. In that situation, the engineer will work with the architect from the start because a lot of design decision will be made depending on what is possible or not with the structure.\n\nSource : I'm an engineer. But keep in mind that this is how we do things in Canada, and this may differ in other country.",
"Here's a rough oversimplification: An architect is an artist. An engineer is a technician. However, architects have to understand math and physics, and engineers need to understand human interaction with their design.",
"This is a very simplistic description. Architects know a little bit about everything (structure, electrical, mechanical, civil), but specifically design. Design being defined as creative problem solving. Engineers know a lot about one thing. Architects coordinate between all the different engineering consultants after coming up with the initial concept design. "
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er94rz | Was Child Rape/Pedophilia Legal During the time of American slavery? | While I do know that rape of african/black slaves was common during those times I’m having an extremely hard time grasping how the rape of children could have been something people acknowledged and accepted as a part of American life?
I know there are cases of young girls and women being raped as children by slave masters but is there any evidence or writings to suggest that such a thing was frowned upon or looked down or even illegal? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/er94rz/was_child_rapepedophilia_legal_during_the_time_of/ | {
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"I don't focus on sexual abuse of children in [this older answer](_URL_0_) but do touch on the issue in the follow-ups. *Obvious* content warning if you click through, or read further, as this is all about sexual assault and violence.\n\nTo reiterate, it was one of the few places where there were any appreciable legal protections, but even they they were quite weak and toothless. One of the few cases of a rape prosecution of a white man against a black person was James Keyton. A Tennessee enslaver, he was brought to court for the crime, *but* he was nevertheless found not guilty. The fact that he was charged at all speaks to just how heinous his offense was viewed by the community; likely a combination of the victim's young age as well as the violence he is said to have inflicted in the act, which flew in the face of the self-image of slavery being *paternalistic* that may enslavers held in the period to try and self-justify their ownership of people. The fact that he was acquitted in turn speaks to the *limits* of censure a white community was willing to bring against a fellow white man for their mistreatment of a black person, no matter how heinous. The indictment from the grand jury was perhaps seen as warning and humiliation enough.\n\nAnother relevant case that we know of wasn't of an enslaver, but rather of an old enslaved man, known only as Ned. He was charged with the rape of two girls, one aged six, the other aged nine. When the crime was discovered Ned was quickly arrested, tried, sentenced, and hanged within the span of two months. The reason though is two fold. The first of course is that he was a black man. The second is that only one of his victims as an enslaved black girl, the other was a young white girl. Had he only committed his crime against the former... it is possible he would have still been pursued by the courts, but certainly without such vigorous prosecution. \n\nCompare that case in Virginia with one in Mississippi around the same period, where an enslaved man named George was charged with raping a young black girl, and much of the focus of the trial was on whether, as the defense contended, the \"crime of rape does not exist in this State between African slaves\". The jury didn't agree, and convicted George, so clearly some Mississippians disagreed, but on appeal, the court concurred with the defense. In response a law was passed explicitly criminalizing the rape of enslaved women, and even allowing for death (or whipping) if they were under 12. Georgia passed a similar law, but of course it still remains telling how they differed by race. If a white man raped a white woman, he could face prison for up to twenty years, while conviction of raping an enslaved woman would likely mean only a fine, presumably paid to her enslaver in any case. Imprisonment was possible, but unlikely to be given by a white jury.\n\nAll from *Rape and Race in the Nineteenth-Century South* by Diane Miller Sommerville"
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4y6iik | How do nerves interpret the movement of molecules as heat? | I understand how objective measurements of temperature work (thermometers, for example), but when it comes to subjectively feeling "hot" or "cold", knowing that the feeling is caused only by molecular speed blows my mind. | askscience | https://www.reddit.com/r/askscience/comments/4y6iik/how_do_nerves_interpret_the_movement_of_molecules/ | {
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"Your cells have ion channels whose permeability to certain ions is influenced by temperature. By changing the permeability of the channels you change the electrochemical gradient of the cell which can easily be translated into an action potential. Really they aren't directly measuring the speed of molecules, they're measuring the change in electrochemical gradients. In fact the reason that capsaicin feels hot is because it interacts with the channels and makes them more permeability so your cells think they are burning. Similarly menthol feels cold because it decreases the permeability of the channels so your cells think they are getting colder.\n\nDisclaimer: Animal Physiology was kind of a long time but if there's one thing that that professor convinced me of it is that your entire perception of the university boils to changes in ion channels."
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5uovu0 | why did competing video stores not have any issues getting all new films, yet competing online services seem to have to fight over content? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5uovu0/eli5_why_did_competing_video_stores_not_have_any/ | {
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"[First sale doctrine](_URL_0_), which was court ruling that stated that once you purchased something you could do with it as you pleased. If a video was available for sale, any video store was free to purchase it and rent it out. Studios could (and often did) release VHS tapes for like $100 at first (\"priced for rental\") to maximize revenue from video stores, and then later on drop the price to consumer-friendly levels. Or they might provide discounted pricing to preferred rental chain, ie. Blockbuster's \"guaranteed in stock\" titles.\n\nStreaming, however, works differently where the platform (Netflix, Hulu, etc.) have to buy the rights to stream for a specific period of time for a negotiated price...",
"Exclusivity costs more. The online services *want* to be the only place you can get something, because that will drive people to subscribe to them. So they enter a bidding war to get content with exclusive rights.\n\nIf they were all fine with all having the same library, it wouldn't be an issue, but then Netflix, Hulu, Amazon, etc. wouldn't have any real reason for you to choose one over any of the others."
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4fg9rz | if food contains so much energy in the kilocalorie scale, why can't we use that energy to power our homes? | We can see the nutritional value of foods sold always provide lots of energy often in the kilocalorie scale (food calorie) and if you convert that to energy values like: joules and watts, it's quite a lot!
The energy one person should eat in a day according to the officials is quite a lot. 2,000 kilocalories as said in Thailand and we know that people are getting obese because they are packing on more calories that that.
2,000 kilocalories is 8.368 megajoules or about 2.324 kilowatthours.
If food packs in so much energy and McDonalds is easy to find and packs in a lot of energy. Why can't we convert the energy in food into real energy like our bodies do it? Why can't we convert this and heat our homes and power our light bulbs? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4fg9rz/eli5_if_food_contains_so_much_energy_in_the/ | {
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"We do, its called diesel fuel. They have similar energy densities, and this is why petroleum is the most common form of transportation fuel. For stationary power plans coal is more common, but it is pretty much the same thing, a complex hydrocarbon.\n\nEdit: also Ethanol, we straight up turn corn into car fuel sometimes, but its generally cheaper to dig up crude in Saudi Arabia...",
"To release the enregy in food we would have to burn it. And there are cheaper things to burn for energy. Wood for example. But while many people still heat their homes with wood, there are a lot more efficient ways to produce energy. That is why we have power plants ;-) Additionally they are equipped with filters to reduce pollution.",
"Food contains energy in the form of stored carbon, just like coal or oil. Pretty much the only technology we've devised to extract that energy involves burning the carbon, using the heat to make steam, and using the steam to drive turbines. This is exactly what happens inside of coal-fuelled and oil-fuelled power stations.\n\nSo to turn your Big Mac into energy we'd basically need to set it on fire and use that energy to boil water. But given all the time and money that's gone into growing grass to feed the cattle to make the burger, we'd be better off simply growing biomass to burn directly.\n\nTLDR -- we *could* turn our food into electricity, but it's far simpler and cheaper to make electricity from other sources."
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wbmk8 | Before the modern era where did people go to report crimes? Who were their 'police' basically? | It's not a specific question because I want answers for every culture and society!
Like, in fantasy novels, there's always a city-watch that functions like a modern police force - did those exist?
Let's say I wanted to report a theft (with no suspect in mind) - did I go to the city guard/watch, or to a local magistrate?
If I wanted to accuse someone of a crime where did I head?
Whose burden was it collect evidence, the person being accused, or the person accusing, or both? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/wbmk8/before_the_modern_era_where_did_people_go_to/ | {
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"Let's say you are living in Tang-dynasty China. Someone steals something from you. The person you go to is the local magistrate - who becomes an investigator and a judge rolled into one. He would often hire people to help him with tasks such as apprehending suspects etc.\n\nThen comes the burden of evidence. By Tang-dynasty laws, a criminal could only be convicted if (s)he confessed. Thus the evidence could be overwhelming - you would still need a confession. If the evidence was strong enough, but the suspect was still not confessing, some light torture was in order until a confession was forthcoming. Now - if this was a petty theft, and the suspect died during torture, the magistrate would probably get in trouble. However, if it was a serious crime, and the evidence was seen as overwhelming, a suspect dying during torture was accepted, as the eventual punishment would be death anyways.",
"Before the 17th century **Japan**, as in most feudal societies, justice was obtained by whatever means a particular lord had in place, and often included some type of magistrate or city watch (in big cities), as well as direct involvement by his samurai (especially in smaller settings like villages). \n\nDuring the Edo Period samurai began to be even more involved in law enforcement, as this period was one of Shogun enforced peace and there were no wars to be fought, so many samurai found themselves without masters or duty.\n\n*Taiho-Jutsu: Law and Order in the Age of the Samurai* by Cunningham is a well written book concerning this subject. [link to a quick review of this book](_URL_0_)\n\nEdit: Clarified the scope to Japan",
"It is very difficult to tell for most premodern societies. Luckily, Iceland left an extensive body of literature that focuses almost exclusively on the issue.\n\nThe Icelandic Althing is generally said to be the oldest Parliament in the world, but that doesn't really capture the nuances of the government. Iceland had a law making body, after a fashion, and a judiciary, after a fashion, but the government had no executive arm. This means that the government could not enforce the laws it made. The Medieval Icelandic government was more or less exclusively a body of its members, with no authority beyond that.\n\nSo what does this mean practically? If, say, Thorstein Halfredsson kills your brother, you summon him to the upcoming court, which you need to do in person (no subpoena officers). In the trial, most of the proceedings are actually taken up by proving you filed the charges correctly. If he is found guilty, he is either fined or sentenced to greater or lesser outlawry. A lesser outlaw is forced to leave Iceland (or just the district) for three years, or face greater outlawry. A greater outlaw is precisely that--someone outside the protection of the law.\n\nSo you get Thorstein sentenced to greater outlawry, but he still needs to be punished. So you round up a group of your family and friends and go find and kill him. He, of course, might not agree to this and will probably flee. In many cases, merely getting the sentence of greater outlawry passed is enough, and no pursuit is carried out.\n\nBut let's say you didn't want to go to trial. Instead, you immediately went to Thorstein and buried an axe in his chest. In that case, the heads of yours and Thorstein's families will get together and hash out an agreement. Very likely, each death will be seen to cancel the other. Alternatively, you can skip the killing part and Thorstein's family will pay some sort of compensation, or Thorstein will perhaps voluntarily accept lesser outlawry.\n\nBasically, Iceland regulated and systematized vigilante justice.\n\nEDIT: My source is Medieval Icelandic literature and Jesse Byock's *Viking Age Iceland.*",
"In Ancient Greece, city states had publicly owned slaves who acted as a police force. They kept order and controlled prisoners, but they didn't investigate crimes. Most crimes were considered a private matter so the citizens dealt with them themselves.\n\nThe city of Rome never had a real police force, though it had a force of men set up for the protection of each ward. These men were responsible more for public order and physical protection and had no role in criminal justice.\n\nOne thing to keep in mind about criminal justice as a whole is that, for most of history, crimes were considered private matters between individuals. Eventually a new idea took hold in England; violating the King's Peace (through murder, theft, etc.) was not just a crime against an individual, but a crime against the whole country. This brought about the prosecution of criminals even when no private citizen brought a case against them.",
"The post-Roman Visigoths in Spain created their own [legal code](_URL_0_) that sets down rules for legal issues like murder, theft, etc. It's an interesting window into the past, if you have few minutes to read through it. ",
"If I recall from a crime and punishment museum I went to in Rothenburg, Germany, at least in that part of the world, they had officials who were in charge of trade laws and other fiscal related crimes. The town guard was in charge of general law and order. As for collecting evidence, I don't remember too much, but I do remember that if at least two reputable men reported the crime, that meant that the suspect was to be brought into city hall or where ever the jail was for \"interrogation\"(torture). "
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1ouu48 | the bank crisis 1837 | Can someone explain to me the causes and lasting effects of it? I kinda understand that inflation went way up, but all the websites I look at use complicated terms that I'm unfamiliar with. Thanks | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1ouu48/eli5_the_bank_crisis_1837/ | {
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"Cause:\n\nLocal banks receive federal bank money and loan too much paper money (not gold or silver) out.\n\nDetails:\n\nJackson hated the national bank and decided not to recharter its bill in 1832. This was the start of the BANK WAR. Jackson believed that a national bank had high interest rates and exploited smaller, western banks. The director, Nicholas Biddle, responded by calling in some of its loans early, creating a mild crisis. Jackson reacted by saying that any loan money the national bank collected would be taken away and put into local banks. These local banks received the deposits in the form of gold and silver and, as banks do, loaned it out to people who needed money. Unfortunately, these local banks loaned the money in the form of redeemable paper notes and loaned out more money than they could back with gold and silver. This caused the PANIC OF 1837.\n\nEffects:\n\nInflation, unemployment, and bank closings skyrocket. The next president, Martin Van Buren, received a bulk of the criticism even though he had nothing to do with the crisis. The panic allowed the rival party, the Whigs, win the office in the next election, which helped serve as a catalyst to the two party system we see today."
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dvrxuz | how does turning down the temperature while away from home actually save energy? | It seems to me that maintaining an internal temperature would require less energy than letting the house cool and then having to crank the furnace on high for an hour or more to raise the temperature back up to a comfortable level, assuming the external temperature is much colder than the internal temperature.
Follow up question: When the external temperature is much colder than the internal temperature, are there any energy savings in keeping the internal temperature lower, say around 17 Celsius vs 21 Celsius? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/dvrxuz/eli5_how_does_turning_down_the_temperature_while/ | {
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"Heating the house back up is something of a fallacy. What you are doing is replacing heat lost to the outside. Think of it as a \"black box\". The only input is your power supply. The only output is heat escaping that needs to be replaced by the supplies you are paying for. The energy loss is a function of the difference between inside and outside temperature summed up over the day so you want to keep that as low as possible.",
" > It seems to me that maintaining an internal temperature would require less energy than letting the house cool and then having to crank the furnace on high for an hour or more to raise the temperature back up to a comfortable level, assuming the external temperature is much colder than the internal temperature. \n\nEverything I've learned about heat transfer says this isn't true. \n\nIn short, heat transfers faster when the temperature difference is greater. \n\nHeaters and A/C output a constant temperature when they're on, no matter what your thermostat is set to. \n\nThink of it this way, if it's 40 F outside and your thermostat us set to 70 F, you're trying to keep the house at a constant temperature. As soon as it hits 70 F, your heat shuts off, because 70 F to 40 F is a big difference, it loses heat very quickly. As the difference in temperature falls, the rate of heat loss also lowers. In comparison if you have your thermostat set to 60 or 65 while you're away, there is still a big difference from 60-65 down to 40 but that difference is less than from 70 down to 40, which means your house loses heat more slowly because your thermostat is lower. This means the heat doesn't run as often as if you try to keep it 70 the whole time. \n\nSo yes, it may seem maintaining a higher temperature would be better, but the actual energy required to raise the house (in winter) from a maintained 65 F to 70 F when you return, is less than the energy required to maintain 70 F the entire time. This is because the greater the temperature difference between inside and outside your house, the more often your units have to turn on, the more often they turn on, the more energy they use. While on, they use the same energy whether they are heating the house 1 degree or 10 degrees, the only difference is how long they run, and heating the house 10 degrees takes less time than heating the house 1 degree 10 times (due to how heat transfer works).",
"I turn my heat / AC completely off if I'm going to be away for more than a day. It doesn't take long or cost much to warm/cool the place when I get back.",
"How much energy your house loses at any given moment is proportional to the difference between the temperature inside minus the temperature outside. Where I am the mid-winter differential is about 40C (+20-(-20)). If I reduce the inside temperature to 15C the temperature difference drops to 35C. For the time period I keep the temperature low, I save 5/40 or 12.5%. \n\nSo if I spend $600 a year on heating, temperature setback would save me $25 a year. (1/3rd of time saving 12.5%)\n \nNow it is not quite that straight forward as the outside temperature is not constant, efficiency of your heating system might affect reheating, your system has to have sufficient capacity to bring the temperature back up, etc. And in a well insulated home, that spends less on heating overall, those saving shrink more (not as a %, but as an absolute $ amount). But the proportion of hours setback can be increased (night, daytime when no one is home, etc).",
"The energy to heat up a house a degree is constant, that is as long as the house is warmer than the freezing temperature of water.\n\nThe rate that heat leaves the house trough thermal conductivity trough the wall depends on the temperature difference. The energy loss is a constant that depends on the isolation multiplied by the temperature difference.\n\nSo the lower temperature difference the lower the heat flow from the house is and the temperature drops lower.\n\nLet's say that it is required 720 000J= 200Wh to raise the temperature 1 degree and the heat loss is 10W/(degree difference). The number is completely made up of simple calculations. So not correct for a real house but they show the principle. \n\nIf the outdoor temperature is 0 and the indoor temperature is 20 the heat loss is 10\\*20= 200W so 200Wh per hour. That is the energy required to keep the house at that temperature per hour. For 3 hours you need 3\\*200=600Wh\n\nIf you turn off the heater and simplify the calculation so the temperature only change at the end of the hour to avoid differential equation. A correct solution will show an even larger difference.\n\nThe first hour you loos 200Wh. That would result in a drop in the internal temperature of 200/200=1 degree to 19 degrees.\n\nIn the second hour, the temperature difference is only 19 degrees so the energy loss is 10\\*19=190Wh . The temperature will drop by 190/200=0.95 degrees to 18.05 degrees.\n\nThe third hour the energy loos is 10\\*18.05=180.5Wh and temperature drop is 180.5/200=0.9025 and the temperature is 17.1475 degrees\n\nTo heat up the house to 20 degrees you need to heat it 20-17.1475=2.8525 degrees and you need 2.8525\\*200=570.5Wh of energy to do that. That is lower then the 600Wh you need to keep it a lover temperature\n\n & #x200B;\n\nSo that simplified calculation shows that the energy needs to keep a constant temperature is higher than to let it drop and to heat it up again.\n\nFor the same reason, you save energy by lowering the temperature because the heat flow is lower. \nEstimation of energy-saving is (17-outdoor temp)/(21--outdoor temp) so at \n\n* 0C is 17/21= 0.81 so a reduction of 19%\n* \\-20 C ( 17+20)/(21+20)= 0.90 so 10 % less\n\nThe most extreme case is if it is 17 degrees outdoors when you need no heating if indoor is at 17 degrees but you need heating to get to 21 so the difference is infinite.\n\nReality is more complex than this, for example, the ground does not have the same temperature as the air, you have ventilation and heat is lost that way."
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5un4u1 | why don't we treat addictions by putting the addicted people into medically induced coma for a long time? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5un4u1/eli5_why_dont_we_treat_addictions_by_putting_the/ | {
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"This wouldn't address the behavioral factors that brought people to their addictions.",
"I like to think half of it is a change of lifestyle.\n\nYou can get rid of the physical addiction, but it'd probably still be on your mind because it's part of your normal day routine.",
"Because addiction isn't just a physical/biological addiction. There is a significant behavioral component. If you don't change the habits, you don't deal with the addiction....pretty much at all.",
"For the same reason that we don't imprison people for simple traffic violations: It would be overkill.\n\nThe costs alone would be more than other treatments that have been proven to be effective. So why use a nuke when a smaller/different tool works just fine?",
"* medically induced comas are expensive and cost more than the harm addiction causes\n* long term comas have very serious side effects\n* they don't treat psychological addiction\n* they don't treat the mental illnesses that lead to addiction\n* they don't treat the environment and economic conditions that lead to addiction"
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6mrg3q | shouldn't many more of us have bed bugs? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6mrg3q/eli5shouldnt_many_more_of_us_have_bed_bugs/ | {
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"Oh they are a real problem. \n\nBut they don't get around too well by riding on people. \n\nThey aren't like fleas, who are highly mobile. Bed bugs are slow and don't jump. So if you sit on a couch with bed bugs, you might pick some up, but they won't be leaping leaping onto passing strangers. \n\nHowever, when you put your clothes in the laundry basket (or on the floor) they will make their steady way into the rest of your stuff.\n\nThe best way to transfer bed bugs is by moving bedding (especially mattresses, obviously) or upholstered furniture between buildings. ",
"Those stories are very true. I just got done dealing with an infestation. Its become an epidemic: _URL_0_\nBut no, you're not just lucky. Currently, you have a better chance of having no bed bugs at all. Only around 15% of apartments currently do.\n\nAlso keep in mind that you may have bed bugs and not know it. For some people, the bites leave no marks, no itching, and no sign anything happened at all. "
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"http://www.slate.com/content/dam/slate/articles/health_and_science/Science/2011/10/111005_SCI_bedBugChart.jpg"
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1yhvk5 | Why are Norway and Sweden not united today? | I know vaguely that Norway and Sweden were united once, though I don't know when they were and when/why this ended. What caused Norway and Sweden to split and when, and why have they remained split?
As far as the other countries of Scandinavia, has there ever been any movement for a sort of "Scandinavian Union"? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1yhvk5/why_are_norway_and_sweden_not_united_today/ | {
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"The economic (and hence geopolitical) interests of the two countries were, and are, quite different; they are separated by a mountain range that makes it difficult to get much overland trade going. Sweden looks east across the Baltic (and south to Germany); Norway looks west, to the North Sea and the Atlantic (and to the UK). The union was relatively loose, consisting mainly of Norwegian foreign and trade policy being decided in Sweden; unfortunately the trade policy was precisely the place where many wealthy and influential men felt they could do a lot better, for the reason outlined above. \n\nThe split occurred in 1905. The immediate dispute was over what was called the \"consulate question\": The Swedish foreign ministry decided where to send ministers and what countries to prioritise, and was not answerable to the Norwegian Storting (parliament). Norway's merchant fleet was (and remains) quite large, and the ship-owners felt that their interests were not being looked after; there was lots of Norwegian trade outside Europe, but few consulates. So, the Norwegian government demanded the right to appoint its own ministers. The Swedes refused, though offering a compromise that in effect left them most of the power - basically they offered to give the Norwegians a formally \"separate\" foreign ministry, it would in effect have been subordinate to the Swedish one. This was referred to in Norway as the \"vassal-state compromise\" (loosely translated; more literally, the \"satrapy points\") and was rejected, leading to the breakup of the union. It may be worth noting that the consulate question had been a thing, on and off, for ten years, and that 1905 was, by some odd coincidence, a high point in Norwegian military power due to a llong-running armament program. \n\nSo, there are underlying economic interests, a direct expression of those underlying frictions in the dispute over what embassies and consulates should be prioritised, and then you have the more ideological point that the nineteenth century, and perhaps especially the turn of the century, was a period of very strong nationalism. The Norwegians felt (and feel) themselves a very separate people from the Swedes, although the difference is perhaps not so visible from the outside. :) \n\n > Has there ever been any movement for a sort of \"Scandinavian Union\"?\n\nSure. It's a perennially popular project among intellectuals; Ibsen was all in favour of it, for example. (And then there's the Kalmar Union, of course.) There's even one on reddit [right now](_URL_0_) that's trying to make a Scandinavian alt-coin, called the eKrona, as the first step to forming a closer economic union. \n\nSource: I learned this in school. ",
" > As far as the other countries of Scandinavia, has there ever been any movement for a sort of \"Scandinavian Union\"?\n\nThe [Helsinki treaty](_URL_0_) was signed in 1962 to \n > ... promote and strengthen the close ties existing between the Nordic peoples in matters of culture, and of legal and social philosophy, and to extend the scale of co-operation between the Nordic countries\n\nSo in a way, there has been \"a sort of Scandinavian Union\" for a while now."
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3n7ys8 | How are metal welds so strong? | I have a hard time fathoming why things don't break at the welds more often. When I think of welding I think of super glue holding things together. And for glue, the glued portion is the weak point. | askscience | https://www.reddit.com/r/askscience/comments/3n7ys8/how_are_metal_welds_so_strong/ | {
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"Because the weld isn't an adhesive. You can think of it like taking two pieces of paper and then instead of making them stick together, you melt the atoms in each paper down and then press them together, then when it cools down its one piece of paper. Overall the welding is weaker than the rest of the metal, but its still much stronger than if you had just glued them together. ",
"Welding is not gluing. When you weld two pieces of metal together, they truly become a single piece of metal. Although the grain structure and exact chemistry of the metal can vary a lot across the weld, it is nevertheless held together by the same kind of bonds that hold each piece of metal together independently. Also, to nit pick, it's not always the case that glue is weaker than what it joins. In many cases the glue joint is stronger than what it's holding together."
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500zby | what is the difference between decibel and sone? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/500zby/eli5what_is_the_difference_between_decibel_and/ | {
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"The decibel (dB) is a unit used to express the ratio of two values of a physical quantity, often power or intensity. One of these values is often a standard reference value, in which case the decibel is used to express the level of the other value relative to this. \n\nThe sone is a unit of how loud a sound is perceived. Often times engineers and scientist refuse to use sone because many consider it to be a subjective measurement and not accurate. "
]
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||
1a1ah2 | what is the big deal about "unlocked" smartphones? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1a1ah2/eli5_what_is_the_big_deal_about_unlocked/ | {
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"an unlocked smart phone would allow you to use it on any carrier, and in the case of Europe put in any SIM card that is prepaid (or pay as you go). It means that you can have a phone that can work on any carrier and not be forced to select from the phones that they have available.\nIts quite useful for international traveling, just get a prepaid SIM and put it in, all your contacts will still be there and everything.",
"Smart phones are quite expensive and so present an entry barrier to cell phone companies who are trying to provide a service. To solve this they sell phones which might cost $800 at only $200 if you agree to a 2-year contract, planning to recoup the cost over the course of the agreement.\n\nHowever, if you can unlock your phone you could switch to a different carrier after taking advantage of the discounted price. They could lease the phones instead, but that puts them in a position of risk where people would break phones they don't own and rightly expect maintenance in the agreement. Rather than switch around their business model and hope it flies, carriers would prefer to just pass laws to enshrine their monopolies on the hardware."
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889wka | mechanical advantage | Could anyone explain me how does it become 4 times lighter in this system of pulleys?
_URL_0_ | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/889wka/eli5mechanical_advantage/ | {
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"Pulleys provide a mechanical advantage depending on how many wheels they have. \n\nThis can be explained using a few simple concepts. \n\nIf you were to tie a rope to an object (let’s say it’s a brick) and you threw the other end over a tree branch, when you pull that end, you pull the brick up even though your pulling the rope down. This doesn’t provide any mechanical advantage, but it is a single pulley system. So the mechanical advantage would be 1/1. \n\nIf you were to tie one end of a rope to a branch, then you swing the other end over that same branch, the. Attack a hook with your brick on the slack between, you have just created a two pulley system. When you pull on the remaining end, the force required to lift your brick has now been halved, and the distance needed to be traveled has doubled. By counting the pulleys you can see that you now have a mechanical advantage of 2/1. \n\nWith odd numbers of pulleys it becomes tricky, as the end of the rope must be attached to the load (like the first example), and then you need to hang the rope from the branch, through a hook on the load/object, and back over the branch. Since there is three pulleys in this system (branch, hook, branch), you have a mechanical advantage of 3/1. \n\nYou can easily expand this to a forth by tying one end of the rope to the tree, then though a hook on the brick, over the tree, through the hook again, and finally back over the tree, you now have 4 pulleys. Just like marks, you will now have a mechanical advantage of 4/1. \n\nIn this example, every time the rope went over the tree or through a hook, it was a pulley. You could actually try this pretty easily at home. \n\nI haven’t yet really explained it, so here is how it had it’s mechanical advantage. The reason you must pull the rope 4 times as far, is because excluding the length of rope your pulling, there are four strands in the system. So every inch you pull must be evenly distributed along all the other ropes. However, this also allows the force of your pull to be distributed across four ropes, essentially multiplying the force you put in by 4 this is your mechanical advantage. "
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1m4igy | English common law and U.S. common law... what, if anything, was kept in the new republic? | With the system of Common Law, cases set precedent for the rule of law, and sometimes, set the laws themselves. Once the U.S. formed its own government, were the former case laws nullified, dropped, or otherwise forgotten? Or, does the U.S. still have old English laws in place despite establishing a new government? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1m4igy/english_common_law_and_us_common_law_what_if/ | {
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"(I'm going to take this on, since it has come up in my research. How it relates to my flair is a long story. The short version is \"church property disputes.\" So while I am a historian, I am not a lawyer, and some of what I think I have figured out may need to be corrected.)\n\nThe American common law tradition did not start over from scratch with just the method. Much was kept and much has gone away, because of the different constitutional situations. \n\nSome of what is different in American common law is different because the US has a written Constitution. In the context of English and Welch law, we do run across talk of a constitution, but there you cannot go to a public display or search on the Internet and find a copy and say, this is it: the English Constitution. There it is more a tradition. So a big difference is that American common law has evolved in new directions because it is interpreting a text rather than a tradition. \n\nMuch else is different because the process of interpreting what the American text provides has pushed American law in new directions. So the right to privacy was deduced in Griswold v. Connecticut from three different provisions of the text of the Constitution. It's a common law principle that didn't exist in England.\n\nWhen I read appellate court cases, especially in the 19th century, I see many references to English precedent. So English precedent used to count for a good bit. In his book *The Common Law* (1881), Oliver Wendell Holmes treated the English tradition as very much alive as a source of precedent for American decisions, while at the same time discussing differences the American context requires. (That would be a good book to have a look at, as long as you bear in mind that it's not a critical history, but a series of lectures making a case for Holmes's view of how things should be.) That has pretty nearly stopped, at least in the cases I read, though I have seen a Supreme Court decision from 1979 that still referred to an early 19th century English case for context. There may be others like that.\n\nOne principle based in the English common law that comes to mind as still in force most places in the US is the rule against perpetuities. It is an English common law principle dating from the late 17th century (with a statutory basis that goes back to Henry VIII's reign) that basically says a trust can't run forever. Every trust has to terminate no later than 21 years after the death of the last person who can be shown to have been conceived at the time the trust was created. (That was the original term; much shorter terms are used in American practice today.) A few American states (Alaska and Kentucky for example; there are others, but I don't remember which offhand) have overturned the rule against perpetuities by statute, but in most states it still applies.\n\nAlso, It is worth mentioning that the common law tradition has always been at least a bit controversial in the US. So the law of Louisiana, for example, is based on the French civil law rather than the English common law. And there is to this day a good bit of bellyaching in some quarters about the fact that in America judges can make law, and not just apply it as a bureaucratic function, so the question really remains open in that sense.\n\nEdit: correcting spelling"
]
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77eeqp | Can people with a cochlear implant hear the direction a sound is coming from? | I guess I'm asking about those who would be classified completely deaf without their implant, are they able to detect where in their environment a sound is coming from like normally functioning ears can? | askscience | https://www.reddit.com/r/askscience/comments/77eeqp/can_people_with_a_cochlear_implant_hear_the/ | {
"a_id": [
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"text": [
"Directional hearing is largely a result of having two ears. Since sound must strike each one at different times depending on the distance and the brain can calculate a heading from that. There's no reason implants can't do the same."
]
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|
f69j35 | why do some cuts heal quicker than others | Ever since i started working as an electrician i frequently get small cuts on my hands. Nothing serious but i noticed these cuts tend to heal a lot slower then when i cut my self while shaving for example. Can somebody please enlighten me? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/f69j35/eli5_why_do_some_cuts_heal_quicker_than_others/ | {
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"Some parts of your body, like the inside of your mouth, are \"primed\" to heal and will heal much faster than other parts. Cuts on your hands, or anywhere where the skin is constantly being stretched and bent will take longer than places where the skin is basically left alone to get on with repairing itself.",
"If you're working as an electrician, odds are that you're working a lot with copper (wires, etc.). Copper is toxic for the human body (although trace amounts of it are necessary for your body to function properly). My guess would be that your hands still have a residue of copper on them when you cut yourself or that you cut yourself on the copper itself. The cut heals a lot slower because of the toxic copper residue that got into the wound. Although copper prevents your cells regenerating it also kills a lot of bacteria that could infect the wound so the cut will heal slowly but there's generally not a huge risk of infection if you keep it clean and maybe put on a band aid.",
"While shaving, you cut yourself with something that is quite literally \"razor sharp\". This produces a clean cut which doesn't do as much damage to the tissue than a cut with something dull. Think about using a dull vs sharp knife in the kitchen: a dull knife will squash and tear the tomato or whatever it is you're cutting. The less tissue damage there is, the easier it is to heal.\n\nYou can't easily see this difference with the naked eye, but it's still a large enough difference to matter for regeneration rates. That's why surgical scalpels have an almost legendary level of sharpness, in order to ensure the minimal amount of tissue damage possible."
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51xirr | advertising with use of a competitor's name | Apologies for that bad title but I'll explain more here..
I've recently seen an advertisement for the Microsoft Surface tablet where, within the advert, the proposed user of the tablet claims they "couldn't do that with my mac".
Does Microsoft have to gain permission from Apple to do this? Do they have to pay Apple to be able to do this? I assume there's something put in place to monitor this kind of advertisement? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/51xirr/eli5_advertising_with_use_of_a_competitors_name/ | {
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"d7fmrt5"
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"score": [
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"text": [
"A Mac is a real thing that exists. You don't need permission to call something by its name. It's honestly that simple. "
]
} | [] | [] | [
[]
] |
|
7xus8y | How did the Vietnamese react upon discovering the Killing Fields, extermination camps, etc during the Cambodian War? | [deleted] | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/7xus8y/how_did_the_vietnamese_react_upon_discovering_the/ | {
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"Follow up question: how well known was extent of the Cambodian genocide by Vietnamese leadership, and what role did it play in the breakdown of relations and decision to invade?",
"Another follow-up question: why did the Vietnamese install former Khmer Rouge battalion commander Hun Sen as the head of Cambodia’s new government? Why not choose someone less tainted with Khmer Rouge association?"
]
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1jzcx8 | how come bottled water is such a hot commodity while other animals can still drink water from unfiltered lakes and rivers? | I understand that pure water = good for you, however why do we place such a high priority for it when any other mammal can drink lake water without any repercussions? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1jzcx8/eli5_how_come_bottled_water_is_such_a_hot/ | {
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"Wild animals have lots of parasites and DO face serious repercussions. There's a reason the animals in zoos live longer and grow bigger than in the wild, and it's not just that they have no predators. Try adopting a stray dog right when it arrives in the shelter; they're full of parasites and need a LOT of medicine to get healthy.\n\nAlso, you've lived your whole life on clean food and water. Your gut is full of friendly, weak bacteria, unadapted to killing off parasites. If you drank contaminated water, you'd build up some degree of resistance as your bacterial flora adapt. But even that won't save you from tapeworms and the like.",
"Animals aren't as susceptible to marketing",
"Marketing. No really, tap water is perfectly fine. Although don't try the lake thing if you are unsure. ",
"Bottled water was mostly a push by the soda companies (Pepsi & Coca Cola) to deal with soda sales that had stopped growing. It's a brilliant scheme, as it is even cheaper to produce than soda, just bottle up tap, and market to the consumer as if there's a difference to sell at rates more expensive than gasoline.",
"Some tap water got contaminated in Europe in the 1970s. Ever since then, the Europeans have primarily drank bottled water.\n\nIn the throes of the revolution that swept across New York City high society in the 1980s, restaurants began serving bottled water. Wall Street financiers were flush from the roaring bull market, and could afford to pay for bottled water that evoked European sophistication (even though NYC tap water is the most delicious shit evah). This caché, I assume, trickled down into the American mainstream. ",
"[this](_URL_0_) if you've ever had it you'll do everything you can to prevent it. Drinking untreated lake water is a good way to catch it. "
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347r0z | How did the leaders of the time, both American and English, react to the Boston Tea Party? | Due to the recent events in Baltimore and seeing several social media posts talk about how the riots in Baltimore are justified in part because events in American History like the Boston Tea Party and Boston Massacre.
So far I've found that George Washington derided the the tea party because he felt as though private property rights where the most valuable. Ben Franklin thought we should pay back the British East India Company. And Sam Adams promoted them. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/347r0z/how_did_the_leaders_of_the_time_both_american_and/ | {
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"I can't speak to the English aspect of things, but the Boston Tea Party made American leaders really uncomfortable. There's a really good book specifically answering your question called *The Shoemaker and The Tea Party* by Alfred Young. In a nutshell, American leaders were not happy with the idea that the lower classes could do that sort of thing. You have to remember that most of the American leaders were wealthy, while many of the rebels were not. In making the nation one of the things that they really wanted to avoid was giving the lower classes to much power and the Boston Tea Party was a very visible reminder that the lower classes, mostly sailors and dockworkers in this case, could overthrow the leaders if they got angry enough. \n\nThe Boston Tea Party was actually largely forgotten (or intentionally erased) after the American Revolution and was not remembered until the early 1800s, not so coincidentally when most of the Revolutionary generation were dead and right at the start of Jacksonianism, which celebrated the average man."
]
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4i56yk | Why were so many early presidents fluent in greek and latin? Did they speak/write in it often? | _URL_0_
Just found this really interesting chart on the multi-language abilities of US presidents. Interesting first of all in how few languages modern presidents speak. But also I was surprised at how popular Latin and Greek were among early presidents. Why was this? Was this just something you did to show off your educated status? Or was this something actually useful to presidents of the time? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/4i56yk/why_were_so_many_early_presidents_fluent_in_greek/ | {
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"Knowledge of Greek and Latin was a fundamental of a classical education. It's not to \"show off\" their educated status, per se, but just a part of being educated. It allowed them to read classical works of literature in their original language, which would also be part of their education. In fact, admission to universities like Harvard required passing a test which included Greek and Latin."
]
} | [] | [
"https://en.wikipedia.org/wiki/List_of_multilingual_presidents_of_the_United_States"
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15vkmt | Are agricultural societies more violent than hunter gatherer ones? | Does anyone know if agricultural, urban societies are more violent (in terms of intra-personal as well as warfare) than hunter gatherer ones? Have any studies been done on this? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/15vkmt/are_agricultural_societies_more_violent_than/ | {
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"That is conventional thinking, that agricultural societies are violent while hunter-gatherers are peaceful, but it's wrong and misleading and draws heavily from the idea of the [Noble Savage](_URL_0_). It's more a matter of the type of violence. Hunter-gatherers, at least mobile ones (there were some sedentary hunter-gatherers) generally don't have the concept of ownership. Different groups may have sort of land-use rights over a certain terrain, but there's no real sense that they own the land. And if conflicts do arise, it's easy to move with your feet and just go somewhere else. So there isn't really war over land or territory. Instead there are skirmishes between groups and interpersonal violence (like murder) that you get anywhere. So it's violence, but it's not war.\n\nAgriculture favours permanent settlement in one place and the accumulation of material wealth in the hands of relatively few people, and this breeds the concept of property ownership, and then subsequently war over land. Early or incipient agriculture doesn't necessarily change a lot, but agriculture lays the foundation for social complexity. It is really with social complexity that you start to see major defensive structures (walls/palisades, fortresses, etc.), permanent military & police forces, and institutionalized violence (i.e. true warfare, not just small-scale skirmishes and raids, though these don't go away).\n\nSo, I'd say that hunter-gatherers and agriculturalists are both just as violent, but the nature and intensity of the violence changes. Hunter-gatherers have skirmishes and interpersonal violence but not so much in the way of warfare or attempts to conquer other people or take over land. Agriculture lays the foundations for the development of social complexity, and social complexity breeds true warfare. Both violent, but different. There are exceptions to these general trends, and particular societies may be more or less violent than others, but in general everyone likes to kill.\n\nNow, all that said, this isn't really history and the anthropology of violence is not my specialty and is only tangential to my research, so I'd suggest that you ask this in /r/Anthropology to get more answers. You should get some people who are more familiar with hunter-gatherer violence in the ethnographic record, as we really don't know a lot about hunter-gatherer violence purely from archaeological data (small-scale events don't leave much of a trace), so what we know is mostly drawn from analogy with ethnographically-known societies. And people who focus on violence will know more about that.",
"Plenty of studies. This is a huge area of debate right now in anthropology and archaeology. I touched on some of it in an [answer I wrote recently](_URL_0_) to a question about Steven Pinker's book (*The Better Angels of Our Nature*), which claimed that hunter-gatherer societies were indeed more violent than urban ones.\n\nI mostly agree with Pachacamac's summary, except to say that the idea of peaceful hunter-gatherers was based on a bit more than the old noble savage trope. There was plenty of ethnographic evidence for little-to-no violence in hunter-gatherer societies (more specifically what are called \"immediate return hunter-gatherers\" in the jargon – basically people who live purely hand-to-mouth) and a convincing explanation of why that should be the case: hunter-gatherers having few material reasons to fight and an easy strategy for diffusing disputes in just moving away. There wasn't anything to contradict this in the archaeological record and it fit with the expectations of classical social evolution theory which sees agriculture as the greater enabler of social inequality and hierarchy. So it seemed reasonable to extrapolate and say that prehistoric hunter-gatherers were peaceful too.\n\nPersonally I think there's still a lot of truth in that position. The evidence for it hasn't gone away, we've just realised:\n\n* that if you're going to treat modern hunter-gatherer societies as representative of *all* hunter-gatherer societies you have to tackle some severe biases in your sample\n* that there is a great deal of variation amongst modern hunter-gatherers\n* that there are crucial differences between different violence on different scales: interpersonal crimes of passion and large-scale warfare are wholly different phenomena\n\nAnd that's led to a lot less certainty about the issue. For contrasting views, you could check out Lawrence Keeley's *War Before Civilization* and Douglas Price's *Beyond War: The Human Potential for Peace*."
]
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|
5u5xxe | why does it always feel like there's somebody behind you in the dark? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5u5xxe/eli5_why_does_it_always_feel_like_theres_somebody/ | {
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"Most human instincts are based on a time and place when it was super dangerous to be out and about in the dark. There were no street lights or flashlights to guide the way. There was little to no protection from dangerous animals. So our subconscious evolved to pay extra attention to sensory input when it's dark out. In our modern lives it's easy to see how this can lead to lots of false positives. ",
"It doesn't feel like that to me. I love the bliss of the night.\n\nGenerally, evolution gave us a better safe than sorry mentality. Checking if someone isn't sneaking up on you is easily done at little cost to you. Facing the consequences if someone does happen to be sneaking up on you is very costly. Any impetus to make you check—especially at a more dangerous time when it's hard to see and help is less likely to be nearby—will generally be advantageous, even if the vast majority of the time nothing is there."
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9rwmgg | why doesnt earthing a connection discharge all the electricity in the circuit? | And if there need to be a completion of a circuit for current to flow, how can the earth ever complete a circuit? Even lighting isnt a complete circuit, is it? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9rwmgg/eli5_why_doesnt_earthing_a_connection_discharge/ | {
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"In normal circuit operation, you need a closed loop to keep the current flowing. But that is only true in \"steady state\"; you can have short term current flow without a closed loop. \n \nAll you really need to get current to flow is a voltage differential and sufficient mobile charge carriers. If you don't have a closed loop (and an energy source), the charge flows and eliminates the voltage difference, then no more current is going to flow. There's no reason that it would. ",
"It would, if the earth ground was connected to every single component in the circuit. \n\nBut this would defeat the purpose of those components since electricity would flow from the source of voltage and out through the earth connection, rather than flowing through the components themselves.\n\nIn general, an earth connection is used to prevent metal structural parts of an appliance such as the outside casing, from becoming electrically \"hot\" if a power wire accidentally contacts them. In this case the excess current will simply be shunted to the ground, keeping the voltage on the casing to basically zero.\n\nIn electrical engineering, this is known as a \"Ground fault\" \"Residual Current\" or \"Leakage current.\" Specifically, a current that travels out through the high voltage \"hot\" prong or terminal, but doesn't return the same current through the low voltage terminal.\n\n\n An example might be the all time stupid idea of using a hair dryer in the shower. Current could potentially flow from the heating coil in the dryer, out through your body, through the bathwater, and into metal plumbing pipes. But having a direct ground connection to the chassis reduces the likelihood of this.\n\nIn any case this is dangerous since even 30-50 miliamps of leakage could cause lethal heart failure. This small of current would not trip a breaker and is much less than the appliance draws in normal use. Many outlets and breakers also have a residual current detecting circuit, designed to detect small differences in output and return current, and quickly shut off the circuit in that event."
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ic95d | How much memory do different animals posses? | Mostly, how much of their environment do different animals remember? How do they know how to return to their nest?
How do they know where the food /water is?
Do insects remember their surroundings? Bees obviously have to remember where their hive is, but what about different insects that simply move around all day without a fixed nest?
Are there any animals that have a better memory than man? | askscience | http://www.reddit.com/r/askscience/comments/ic95d/how_much_memory_do_different_animals_posses/ | {
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"Different animals might have different kinds of memory that are useful in their environment. For example, Clark's nutcrackers have really good spatial memory. Studies have shown that they can remember where they stored food for the winter better than graduate students, but they may not necessarily \"remember\" a particular graduate student.\n\nAnts aren't exactly able to \"remember\" where their nest is, but through path integration, which means they have to \"remember\" all the turns they made from one place to another, and make calculations in order to get back.\n\nTHat is what I know.",
"It depends on the animal and the situation.\n\nThe food/water location is a different question because that involves largely things like smell - this requires that the animal has a very developed olfactory system in the brain. While this is a form of memory, it is not the \"typical\" kind of memory.\n\nDrosophila (fruit flies) actually have very good memory. They can be trained (classically conditioned) in certain ways, and researchers can even erase their memory with the same drug that erases memory in rodents. Furthermore, their memory can be enhanced by having more of the protein that this drug inhibits - see [this article here](_URL_0_).\n\nI study [Aplysia californica](_URL_1_), a giant sea slug. They have no brain to speak of, just clumps of nerve cells called ganglia that are connected in specific ways with specific functions. They in fact only have around 20,000 extremely large neurons. \n\nMy supervisor once described them as \"barely alive\", but they can still demonstrate associative memory: this involves pairing a tactile stimulation with a shock so the slug remembers that the touch signals a shock. \n\n > Are there any animals that have a better memory than man?\n\nFirst, please use inclusive language: *humans. And this also depends - what kind of memory? Our olfactory memory sucks in comparison to rats, for example, but our associative memory is probably superior but there is no real concrete evidence to this effect. I imagine if we subjected humans to those water maze/radial arm maze tests that rats do all the time we would probably out perform them.",
"The most impressive bug memory I know of are the moths who remember being tortured with electrical shocks as caterpillars, despite their brain liquifying during their chrysalis phase.\n\n_URL_2_\n\nBees are indeed also have impressive memories that not only help them find their hive, but also let you train them to detect explosives:\n\n_URL_1_\n\nAnd they can remember numbers (and count) up to 4\n\n_URL_0_\n"
]
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"http://en.wikipedia.org/wiki/California_sea_hare"
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"http://www.homelandsecuritynewswire.com/los-alamos-perfects-bee-explosives-detection-teams",
"http://www.sciencedaily.com/releases/2008/03/080304200858.htm"
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|
1hw7om | When did streets stopped being narrow and crooked and started being wider with wide sidewalks and straight? | Also, were the streets in ancient Rome (or any other roman city) straight? When did the "grid" layout started becoming more common? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1hw7om/when_did_streets_stopped_being_narrow_and_crooked/ | {
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"The Romans actually made some of the straightest roads in the world since it was the empires life blood. \n\nBut in modern times its probably when we started to pave all the roads that it became easier to do in a straight line than a curved one."
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|
3i91uf | why are some people able to survive huge falls while some die instantly from much smaller ones? | Vesna Vulovic survived a fall from 33,333 feet. There are people that fall from apartments windows, much lower down yet they often die. Is it just down to how they land? Or something more complex? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3i91uf/eli5_why_are_some_people_able_to_survive_huge/ | {
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"A mixture of extreme luck and what you land on. If its concrete your dead, if its grass or dirt you have a very small chance of bouncing a few times breaking lots of bones but still potentially surviving. Human terminal velocity is 120 mph (your top speed in a free fall) so just think about the different types of materials that you could hit in a 120 mph collision and survive.",
"Certain parts of your body are much more important if you want to stay alive than other parts. For example if you fall 5 feet and land on your head, the force of that fall might cause a small fracture in your neck or other part of your spine. Because the spine carries nerves, even a small fracture can damage the nerves you need to breathe or move at all. This can easily kill you.\n\nOn the other hand landing on your feet from 5 feet up is unlikely to hurt you at all, and if it does a fractured ankle won't kill you.\n\nAnother factor here is that the neck is actually easier to injure than the legs or feet-- this is pretty much because the legs are meant to be the ones on the ground and the neck is not supposed to be there. Injuries of this kind are not common enough for humans to develop tough necks when they usually don't need them.\n\nHead injuries are also very nasty. Breaking the femur, which is large bone in your leg, can also kill you because of the internal bleeding that huge injury causes. But most other bones in the limbs are not life-threatening if you get medical care. So it's partially about what part of your body gets hurt. "
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7o4q5u | why does perception of color change after taking off ski goggles? | I was out shoveling in the snow storm that hit NYC wearing red-pink ski goggles. When I came back into the house and took them off, everything had a greenish hue. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7o4q5u/eli5_why_does_perception_of_color_change_after/ | {
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"The brain automatically tries to balance our perception to a reasonable white balance which means a tinted lens or lighting will be compensated for given time. But once they are removed it also takes a while to adjust back.\n\nUltimately this tendency probably goes back to some very basic functions of nerves which reduce response to repetitive sensations.",
"Your brain handles \"white balance\" the same way a camera does, in that it recognizes an artificial tint and \"normalizes it\" so that a white object viewed through an orange lens still registers as white to your brain. When you take the lens off suddenly, it takes the brain a little while to re-calibrate for the difference in colors.\n\nYou can notice the same thing when it comes to different light sources. If you are indoors around dusk, you can look around your house with the lights on and see things as \"normally\" colored, but if you look out the window, everything outside looks very blue. The outside isn't actually lit by blue light, it's that the light in your house is very orange, and your brain has corrected for that color cast. ",
"Your eyes have special cells called Cone Cells that give you the ability to see color. You have three types of cone cells - S (short wave), M (medium wave), and L (long wave), but for the sake of simplicity, we'll respectively call them blue, green, and red. (Fun fact: The absence of any or all of these cone types are what result in the different types of color blindness).\n\n\nNow when you wear your snow goggles, the rose colored lenses are effectively blocking all of the visible light and only allowing the red color wavelength to pass through and reach your eyes. AS a result of this, your red cones are detecting the red light while the other two cone types are essentially in the dark. After awhile, your eyes will become adjusted to the condition while wearing the rose goggles. Once you go back inside and take off your goggles, your green and blue cones will suddenly be bombarded with light, as if somebody quickly opened the curtains in a pitch black room. From the blue and green cones' perspective, everything will appear much brighter while your red cones don't notice any difference at all. As a result, your mind will see the blue-green color wavelengths much more clearly and overshadow the red color wavelenth and make everything appear a greenish blue hue. This will continue until your green and blue cones become acclimated to the light and balance everything out."
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1nhfdr | Does electrolysis work to separate hydrogen and oxygen from salt water? or does it have to be purified first? | askscience | http://www.reddit.com/r/askscience/comments/1nhfdr/does_electrolysis_work_to_separate_hydrogen_and/ | {
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"[This page](_URL_0_) has a good explanation of the processes involved in the electrolysis of brine (a saturated NaCl solution). You do create hydrogen gas via this reaction, but instead of O2 you will form Cl2 (chlorine gas) at the other electrode. ",
"Yes, electrolysis will still split water into H2 and O2. However, as this is an oxidation process, small amounts of chloride ions will be oxidized and combined to form Cl2, which renders the process slightly hazardous. "
]
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1fk7rp | African-American Islam and the civil rights movement? | There were many influential Black Muslims in the Civil rights movement; and this was when the "Militant African American" stereotype was common. And when a new wave of Afrocentrism (Black Power, Black Panther Movement, etc.) was sweeping the US.
To what degree is this movement in African-American Identity connected to Islam?
How is the marginalization of Islam then, similar to the the passive "patriotic xenophobia" that is part of the post-9/11 United States?
The more I look I find it clear that there isn't yet a concise answer to this yet,
But if anyone has any thoughts I'm curious. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1fk7rp/africanamerican_islam_and_the_civil_rights/ | {
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"One thing I think you should make note of, and be careful not to mix, is the definition of African American members of Islam and African American members of the Nation of Islam (NOI). While superficially the two look similar, the differences are vast and important. The NOI is more responsible for the Black Power and Black Panther movements than Islam itself. Many of the former members of the NOI ended up converting from the NOI to more mainstream version of Islam (such as Malcom X and Muhammad Ali to Sunnism).\n\n\nI think, then, it is best to talk about the NOI to see how it helped spark the movements mentioned above and why members of the NOI were often marginilized by society and other leaders of the Civil Rights movement.\n\n\nWhile the NOI is in agreement with Islam on many things such as drugs, alcohol, and Allah, it was not formed until 1930 and most of its vocalized opinions are vastly different from Islam proper. The most notorious belief of the NOI was that the \"Black\" race is the original race and that all other races came from them. In addition, they believe that \"White\" people were created by a scientist named Yakub on a Greek island who established dominance over Blacks and put in place a system to control them, even though Black people are the dominant race. Additionally, the NOI believed in a thing called \"Mother Plane\", a UFO that is a small human built planet, carrying bombs, that appeared in Biblical times to the prophet Ezekial. (**OPINION WARNING**) Really, it might be more accurate to compare what the NOI was to something like Scientology than traditional Islam.\n\n\nSo during the Civil Rights movement, there was a large (intentional) divide between Dr. King's movement and the Black Power movement. While Dr. King Jr. and the SCLC advocated a society of equality between Blacks and Whites through nonviolent protest and boycotts, the NOI sought to assert dominance over Whites by military action and thus did not draw the same societal support that the former organization did. \n\n\nThe more \"balanced\" organization between the two would be the Student Nonviolent Coordinating Committee (SNCC; \"Snick\"). It was a younger movement than the SCLC and advocated more extreme measures like the Sit Ins and Freedom Rides during its earlier days (something King did not actively promote) and evolved into a Black Power movement in the late '60s to protest the Vietnam War.\n\n\nSo a final answer? Islam proper in the Civil Rights movement didn't have as much of a connection and presence as the NOI did, and due to the extremist views of the NOI (and many Americans mistaking the NOI for being close to traditional Islam), Islam got bad press well outside its effective influence. Malcom X, after traveling to Mecca, renounced the militant views of the NOI and its segregationalist policy (as opposed to the integration policy of the SCLC) and started to lead the Black Power movement toward more traditional Islam and while still advocating Black empowerement, disavowed the racism of the NOI.\n\n\n*Edited a bit for spelling... If I find any more, I'll try to fix*"
]
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5gngc3 | why can't you pay for gift cards with a credit card? | I get the redundancy of it. You're basically transferring money from one card to another. But why is it not allowed as opposed to not being recommended? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5gngc3/eli5_why_cant_you_pay_for_gift_cards_with_a/ | {
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"At some stores, the 2-3% bank charge on a credit card transaction isn't worth it. Let's say you buy a $100 gift card with your credit card, the store only gets $97.50. That's losing $2.50 up front, and usually the reason you can't get cash for unused gift card balances.\n\nThat said, I bought several as gifts this weekend with my credit card, at merchants that figured they'd lose that money when they take a credit card for merchandise. So you can pay for gift cards with credit cards in some stores.",
"I'm not sure what you mean. I've bought plenty of gift cards using a credit card, and recently too, since it is the holiday season.",
"Gift cards are a common avenue of fraud. \n\nWhat happens if you steal a purse and want to steal money from the person? You take the cash from the wallet but these days it probably isn't much. So now you try to use their credit cards before they are cancelled.\n\nSo what do you buy? You don't want to race out to Macy's and buy a bunch of clothes because what you really want is cash for rent, alcohol, and drugs. Instead you buy a gift card with your stolen credit card, and sell that gift card below face value somewhere such as online. By the time they figure out the transaction was fraudulent and revoke the gift card the thief is long gone with their cash. \n\nIf the store has been burned a few times that way they can just refuse to sell gift cards on credit.\n\n\n\n\n\n\n\n\n",
"Gift cards, especially to major businesses (such as grocery stores) have a second-hand market very close to purchase price, and can be resold relatively easy without much worry about being caught. Many other goods are difficult to quickly resell for any appreciable value. In places where card fraud is prevalent, many businesses restrict the purchase of gift cards. \n\nIf I were a criminal with a new batch of CC stripes, I could easily go around buying $50 gift cards, turn around and sell them off for maybe $40, do this a few times on that one card and then ditch the number, and pocket the cash.\n\n"
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1yr5nn | To what extent was Congress's declaration of war on Germany in 1917 a reflection of American public opinion at the time? | I know during WW2 America's declaration of war on Imperial Japan and Nazi Germany was (for the most part) supported heavily by the general public. I was simply wondering if this was the same way during WW1. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1yr5nn/to_what_extent_was_congresss_declaration_of_war/ | {
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"This is a huge question; American public opinion changed quite often over the period 1914-1917 in reaction to such things as the Atlantic U-Boat campaign, the Zimmerman Telegraph, the Dublin Uprisings, and other events. The American public at this time - like at any time - was hardly a single mass, either, and that definitely had an important effect. \n\nBut broadly speaking - yes, the declaration of war on Germany reflected a pro-British outlook from \"the man on the street\". \n\nInitially, polling during 1915 indicated the American public was strongly in favour of remaining neutral. Unsurprisingly, this was especially true in places like the mid-west (where lots of German-speaking immigrants had settled), and areas heavily Irish-American. Woman's movements and the clergy were also fairly pleased at the declaration of neutrality, although it would be overstating the case to claim there weren't fractures within these communities as well.\n\nIf America was neutral, however, the effect was decidedly pro-British. The economy remained on a civilian footing, which should theoretically have served both sides equally well; however the close proximity of Canada, and the blockade of Germany by the Royal Navy, made it far less risky to provide loans and credit to British manufacturers. Companies saw a chance to extend their influence; JP Morgan, for instance, raised cash for the French war effort despite it being specifically banned by the American government. The fact the America primarily spoke English has also been pointed to as a reason American opinion slowly swung towards supporting the British; English-language sources (newspapers, books, movies) coming from Britain could be quickly and easily distributed, with a penetration German-language sources couldn't match. \n\nThe Germans didn't particularly help themselves in this regard either. With their surface fleet bottled up in Kiel, the interdiction of enemy shipping had fallen to primitive U-Boats. The attack on the Lusitania became a symbol of the outrage this type of attack generated; while definitely not \"the straw that broke the camel's back\" in regard to American entry into the war it is sometimes claimed as, the Lusitania was definitely widely reported and strongly condemned. \n\nThe final act in the drama was the Zimmerman Telegraph. It is an extraordinay document; the Germans calculated that they had to resume unrestricted U-boat warfare to cut grain shipments from Canada. They also knew this would probably militarily bring the US into the war regardless of how it was framed. They therefore cabled their Ambassador in Mexico to propose a trade - if Mexico joined the Central Powers, and America entered on the side of the Entente, then Mexico should invade the south of the United States. At the end of the war, Mexico could keep New Mexico, Texas, and Arizona. The British intercepted this and gleefully handed it over at the most opportune moment. I don't have to tell you, but the average Joe American was *not happy when they found out*. \n\nBut in summary, it was the culmination of lots of different events which tipped public opinion into supporting war; by 1917 Americans were definitely keen for a scrap as a result. "
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3mu6im | Alvin C. York | Hello all. Long-time reddit/askhistorians reader, first time posting. So, I'm a senior History major and after visiting the Sgt. Alvin York home in east TN last month I've decided to write my Senior seminar paper on that subject. Here are my two questions, would love to hear you guys' thoughts on either or both: (1) First, it seems like every major question about York has already been answered. He was a pretty simple man so there wasn't a lot of mystery. Can you think of any questions that maybe the history community so far has relatively neglected to explore about York and his life; questions that I could explore to hopefully add something original to the conversation? (2) Obviously, a senior seminar paper requires scholarly sources including secondary. Problem with York is, almost everything that was written about him was primary/eyewitness, and almost everything that has been written is popular history, not really academic. Any ideas on places I could look? Thanks, y'all! | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/3mu6im/alvin_c_york/ | {
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"The Tennessee State Museum in Nashville used to have a display on York- including the old Sharps and Hankins rifle he hunted with as a boy. There's also some York stuff at the [TN State Archives](_URL_0_) \n\nMyself, I'd prefer a trip to Jamestown over Nashville, but that looks like a better place to start."
]
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"http://sos.tn.gov/search/node/Alvin%20York"
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cki7ls | what is a motif in music? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/cki7ls/eli5_what_is_a_motif_in_music/ | {
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"Your motif is part of music that's repeated to invoke a specific emotion or feeling in a musical piece.\n\nI'm some styles of music a motif will come back always the same to create familiarity, In other pieces a motif can change a little bit every time it comes back so the motif develops like a character in a story."
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||
3uu5lh | why do astronauts wear white? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3uu5lh/eli5_why_do_astronauts_wear_white/ | {
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"Astronauts wear white to reflect sunlight. Otherwise the spacesuit would get too hot and the person inside could be in serious danger, or even die, from being too hot. One layer of the space suit is called the [Liquid Cooling and Ventilation Garment](_URL_0_) which also helps the astronaut from getting too hot.",
"To reflect heat.\n\nAlthough we hear about space being very cold, in fact it is difficult to lose heat in space due to the lack of any substance to transmit the heat to. The only way to get rid of heat is through infra-red radiation, which takes a long time.\n\nThe problem is that astronauts generate body heat faster than they can get rid of it, so much that they have to have cooling fluid pumped around their spacesuit. \n\nSo the last thing you want is the spacesuit and occupant also warming up due to exposure to the sun, hence the suit is white."
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2tlhls | whatever happend to kony2012 and why isnt there something similar for boko haram who's actions have been much worse? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2tlhls/eli5_whatever_happend_to_kony2012_and_why_isnt/ | {
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"Probably because Kony2012 didn't do anything. ",
"If I recall correctly, there were two main reasons why the Kony 2012 hype quickly died down:\n\n1) People who were actually familiar with the situation spoke up and basically said the Kony issue was no longer relevant / significant anymore and they had no idea why this guy was trying to start the campaign\n\n2) The director of the campaign was caught publicly masturbating shortly after Kony 2012 started to become a thing and this news (which made a lot of headlines) mostly discredited the campaign",
"Remember #saveourgirls ? That was about Boko Haram. We sent advisors to help find them, but things didn't work out because the Nigerian army was found to be too corrupt and incompetent to work with. It's no longer a hopeful or good-news story.\n\nThere are anti Boko - Haram activities going on all the time in Africa. That group has lost some battles and many soldiers.\n\nBut what else would you expect to hear about it? It's not big news in America. You have to search for it & find the details in international news. \n"
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1q2rod | How did the Vatican respond to the Fascist Italian Government? | I Googled the topic and most sources seem to suggest the Vatican was very pro-fascism and benefited financially from Mussolini's rule; Mussolini also "sucked up" to the Roman Catholic Church a lot.
I'm wondering if there's more to the story and would love any extra information on the subject. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1q2rod/how_did_the_vatican_respond_to_the_fascist/ | {
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"The two were in direct conflict almost immediately until they agreed to the Lateran Treaty. They were basically fighting over the power to indoctrinate Italy's youth. The Church also believed that Fascism contradicted their stance on free will, and believed Capitalism (Liberty) was preferable to Fascist Corporatism.\n\nIn Italy, the Church had youth groups (e.g. Catholic Boy Scouts) that they used to teach Catholicism to kids. Mussolini, who believed Italy's youth belonged to the State, wanted to outlaw these youth groups and make it mandatory for them to attend Fascist public schools. These Fascist schools actually contradicted the Church's teachings in many ways and they also tried to turn kids into Fascist militants. As a result, the Catholics and Fascists actually engaged in street battles, and the Fascists killed priests.\n\nThe Lateran Treaty gave the Fascist state control of Italy's youth while the Church was given sovereignty (something they've wanted for decades) which also exempted them from taxes but they were also paid back for all the property Italy seized from the Church.\n\nFrom what I can tell, Italy made Catholicism the State religion but by making the Church a sovereign state it no longer had control over Italy's laws, giving the Fascists more power."
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|
14lqfh | Why does the passage of time change when space is curve? Or, why/how is time so inextricably linked to space? | **curved
I understand how space can be curved with gravity, but I don't understand why this changes the passage of the time in that space. I hear about the space-time web, but why is time linked to space in so much that if the space just changes shape (curves), so does the time? | askscience | http://www.reddit.com/r/askscience/comments/14lqfh/why_does_the_passage_of_time_change_when_space_is/ | {
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"The answer is ultimately because that's how the universe works. This is really all science can say.\n\nWe've rigorously shown via the scientific method that this model of reality is extremely accurate and precise at predicting the behaviour of the universe, but that's all science actually does. The question 'why' is a philosophical one.",
"So let's start with space-like dimensions, since they're more intuitive. What are they? Well they're measurements one can make with a ruler, right? I can point in a direction and say the tv is 3 meters over there, and point in another direction and say the light is 2 meters up there, and so forth. It turns out that all of this pointing and measuring can be *simplified* to 3 measurements, a measurement up/down, a measurement left/right, and a measurement front/back. 3 rulers, mutually perpendicular will tell me the location of every object in the universe. \n\n*But*, they only tell us the location relative to our starting position, where the zeros of the rulers are, our \"origin\" of the coordinate system. And they depend on our choice of what is up and down and left and right and forward and backward in that region. So what happens when we change our coordinate system, by say, rotating it?\n\nWell we start with noting that the distance from the origin is d=sqrt(x^2 +y^2 +z^2 ). Now I rotate my axes in some way, and I get new measures of x and y and z. The rotation takes some of the measurement in x and turns it into some distance in y and z, and y into x and z, and z into x and y. But of course if I calculate d again I will get the *exact same answer*. Because my rotation didn't change the distance from the origin. \n\nSo now let's consider time. Time has some special properties, in that it has a(n apparent?) unidirectional 'flow'. The exact nature of this is the matter of much philosophical debate over the ages, but let's talk physics not philosophy. *Physically* we notice one important fact about our universe. All observers measure light to travel at c regardless of their relative velocity. And more specifically as observers move relative to each other the way in which they measure distances and times *change*, they disagree on length along direction of travel, and they disagree with the rates their clocks tick, and they disagree about what events are simultaneous or not. But for this discussion what is most important is that they disagree in a very *specific* way. \n\nLet's combine measurements on a clock and measurements on a ruler and discuss \"events\", things that happen at one place at one time. I can denote the location of an event by saying it's at (ct, x, y, z). You can, in all reality, think of c as just a \"conversion factor\" to get space and time in the same units. Many physicists just work in the convention that c=1 and choose how they measure distance and time appropriately; eg, one could measure time in years, and distances in light-years. \n\nNow let's look at what happens when we measure events between relative observers. Alice is stationary and Bob flies by at some fraction of the speed of light, usually called beta (beta=v/c), but I'll just use b (since I don't feel like looking up how to type a beta right now). We find that there's an important factor called the Lorentz gamma factor and it's defined to be (1-b^2 )^-1/2 and I'll just call it g for now. Let's further fix Alice's coordinate system such that Bob flies by in the +x direction. Well if we represent an event Alice measures as (ct, x, y, z) we will find Bob measures the event to be (g\\*ct-g\\*b\\*x, g\\*x-g\\*b\\*ct, y, z). This is called the[ Lorentz transformation](_URL_2_). Essentially, you can look at it as a little bit of space acting like some time, and some time acting like some space. You see, the Lorentz transformation is much *like* a rotation, by taking some space measurement and turning it into a time measurement and time into space, *just like* a regular rotation turns some position in x into some position in y and z. \n\nBut if the Lorentz transformation is a rotation, what distance does it preserve? This is the really true beauty of relativity: s=sqrt(-(ct)^2 +x^2 +y^2 +z^2 ). You can choose your sign convention to be the other way if you'd like, but what's important to see is the difference in sign between space and time. You can represent all the physics of special relativity by the above convention and saying that total space-time length is preserved between different observers. \n\nSo, what's a time-like dimension? It's the thing with the opposite sign from the space-like dimensions when you calculate length in space-time. [We live in a universe with 3 space-like dimensions and 1 time-like dimension](_URL_3_). To be more specific we call these \"extended dimensions\" as in they extend to very long distances. There are some ideas of \"compact\" dimensions within our extended ones such that the total distance you can move along any one of those dimensions is some very very tiny amount (10^-34 m or so).\n\n[From here](_URL_1_) or [here](_URL_0_)"
]
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"http://en.wikipedia.org/wiki/Lorentz_transformation",
"http://en.wikipedia.org/wiki/Spacetime#Privileged_character_of_3.2B1_spacetime"
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32la0w | If the Universe were shrunk to something akin to the size of Earth, what would the scale for stars, planets, etc. be? | I mean the observable universe to the edge of our cosmic horizon and scale like matchstick heads, golf balls, BBs, single atoms etc. I know space is empty, but just how empty? | askscience | http://www.reddit.com/r/askscience/comments/32la0w/if_the_universe_were_shrunk_to_something_akin_to/ | {
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"The radius of the Observable Universe is about [4.3e26 m](_URL_4_). The radius of the Earth is [6.37e6 m](_URL_7_). So, your scale factor is about [1.5e-20](_URL_10_). Everything in the Universe shrinks by that amount and now fits into the size of the Earth.\n\nSome fun numbers:\n\n* Earth itself is now [0.1 picometers](_URL_2_) in size, or about 100 times the radius of a proton.\n* The Sun is now [10.5 picometers](_URL_3_) in radius, or about half the radius of a hydrogen atom. The Moon is around half that distance away from the Earth.\n* The semi-major axis of Pluto going around the Sun is [90 nanometers](_URL_5_), of order the size of a virus.\n* The nearest star system, Alpha Centauri, is about [half a millimeter](_URL_8_) away, or about ~~half the thickness of a red blood cell~~ the size of an amoeba.\n* The Galaxy is now about [7 m](_URL_6_) in radius, so about four people tall.\n* The distance to Andromeda, the nearest large galaxy, is about [350 m](_URL_0_), almost a quarter of a mile away.\n* The distance to the Virgo Cluster of galaxies, the nearest big cluster, is about [7.4 km/4.6 mi](_URL_9_) away.\n\ntl;dr: space is big.\n\nEDIT: I goofed on Alpha Centauri, thank you /u/W6hwy5Zf ! Fixed.\n\nEDIT 2: Thanks /u/lludson!\n\nEDIT 3: Speed of light calculation by /u/TimS194 for those asking: [link](_URL_1_).",
"One of the strangest things about this degree of scale – something that strikes me as inexplicably *weird* – is how incredibly slow the speed of light is over galactic distances. \n\nEven in our tiny little neighborhood, it takes 8 minutes for light to travel from the Sun to the Earth. Imagine standing by a small lake; out in the middle is a 1\" floating ball that represents the Sun, and at your feet – right on the shoreline – is a speck representing the Earth at scale.\n\nImagine throwing a stone that splashed right beside our “Sun.” Now picture a ripple that takes a full 8 minutes to reach the shore. Bizarre, isn't it? The notion that our universal speed limit is so… lethargic… is so strange that it's creepy. It gives me the willies.\n\nIt gives me the feeling that if we knew why this was the case, it would literally be like taking the red pill, as some people speculate that this is evidence in favor of the argument that we're living in a simulation. ",
"Here's something pretty cool. The largest observed star, VY Canis Majoris, would be [47.01 nanometers in diameter](_URL_1_).\n\nBy comparison, the sun would be [00.02013 nanometers](_URL_0_).",
"I hope this can help you! _URL_0_",
"_URL_0_\n\nThat video explains it pretty nicely. ",
"Not the answer to your question, but I was reading The Elegant Universe by Brian Green, and I found this comparison incredible:\n\nIf you increased the size of an atom to the size of the observable universe, a Planck would be about the size of an average tree.\n\nOr something to that effect. At the quantum level, size and position and speed are not simultaneously knowable quantities it would seem.",
"I've always found the phrase 'Space is big' very telling of our species egocentrism. It's not that space is so big, it's that we are so small. \n\nIt's also quite telling that oftentimes when we imagine advanced alien technology it's of a vast scale beyond anything humans have ever built. Like the Death Star, Independence Day, the Borg, Stargate, etc. \n\nFunny how most of us aren't as equally compelled by the idea that there may be aliens visiting us all the time at the near sub-atomic scale. I've never seen a UFO pic where the craft was the size of a dust grain. Nope, somehow advanced aliens have to be our size but with \"bigger\" technology. \n\nFor all we know there may be living organisms in this Universe where a single individual is the size of our planet or larger. If our species egocentrism is anything to go by; I'm not even sure creatures of this scale would even consider us to be alive.",
"Not the same scale you are specifically asking about, but there is a fantastic scale model of the solar system in Melbourne Australia that helped me tremendously in visualizing the scale of the solar system and almost unimaginably empty space is. It starts at one end of St. Kilda beach with the sun. Here's a picture of me sitting on the model of the sun: _URL_0_\n\nAt that scale, the earth is a short stroll away, maybe a 3 minute walk. It's about the size of a marble. The planets continue down the beach to Uranus, but it will take an hour to walk there.\n\nThey also have almost right next to the sun, another model star, about a third the size. The plaque helpfully explains that it is Proxima Centuri, and that it is shown the correct scale for distance to the sun.... after having gone around the earth once. That's how far away the next nearest star is other than the sun.",
"the observable universe has a diameter of about 8.7\\*10^(26) m, while the Earth has one of about 1.3\\*10^(7) m. That's a factor difference of 6.7\\*10^(19). So you need to scale everything down by that much.\n\nHow much is that? Well, an atom only has a diameter of about 10^(-10) meters, so if you do this shrinkage, anything about 10^9 meters across would shrink to the size of an atom. The Earth would shrink to around 100 times smaller, so the size of the nucleus, IIRC. The Sun though, would be just about the size of an atom. By comparison, a golf ball is ENORMOUS; about 3 \\* 10^8 times as big as an atom. So, what's that much bigger than the Sun? Well, looking at the numbers on wiki, it seems that the diameter of a golf ball just about corresponds to the distance the sun is from the center of our galaxy, which is also about a golfball length from the edge of the galaxy.\n\nSo to sum up, if I did my numbers right, You shrink the observable Universe to the size of Earth. Now put 4 golf balls in a row, touching. That's our galaxy, and the Sun is a single atom at the point the first and second golf ball touch.",
"\"On a diagram of our solar system to scale, with Earth reduced to about the diameter of a pea, Jupiter would be over a thousand feet away and Pluto would be a mile and a half distant (and about the size of a bacterium, so you wouldn’t be able to see it anyway). On the same scale, Proxima Centauri, our nearest star, would be almost ten thousand miles away. Even if you shrank down everything so that Jupiter was as small as the period at the end of this sentence, and Pluto was no bigger than a molecule, Pluto would still be over thirty-five feet away.\" \n\nSo, uh..yeah, there is a lot of space out there.",
"I think everyone is missing the point of the question. The universe is infinitely expanding and so the correct answer is that everyrhing else would be infinitely small. But assuming we took the size of the universe at an instance I think stars would be too small to even put a number to. Like, smaller than the smallest thing",
"Well... the viewable universe is around 14 billion light-years in every direction. The Earth has a radius of about 6,400,000 meters, and our galaxy is roughly 100,000 light-years across...\n\n1 lightyear would be about 1/2 a millimeter. Our galaxy would be roughly 50 meters across. The distance to Andromeda would be just over a kilometer, and it would be 100 meters across.\n\nSirius would be about 3mm away from the sun, and the sun would be about 1/50th the size of a hydrogen atom.\n\nUnless I've gotten off by a couple factors of 10 somewhere the above should be pretty accurate."
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fblc3y | why does vasoconstriction lead to better blood flow? | I keep reading, as a science student, that when blood flow or pressure goes down, arterioles constrict in order to raise blood pressure. But vasoconstriction actually increases resistance, thereby depriving the tissue further of blood flow.
So what is it that I'm not understanding? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fblc3y/eli5_why_does_vasoconstriction_lead_to_better/ | {
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"Vasoconstriction does not increase blood *flow*. It increases blood *pressure*. If all things were equal, that would normally increase blood flow. But as you note, making the blood vessels smaller increases the resistance to flow. \n \nIf you grab a hose or piece of tubing with liquid flowing through it and squeeze, the upstream pressure rises due to the resistance you've added. But the rate of flow goes down."
]
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79fbf6 | why are "girl" pushups so much easier than regular ones? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/79fbf6/eli5_why_are_girl_pushups_so_much_easier_than/ | {
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"There was an r/askscience post that blew up a couple days ago about what percentage of you body weight do you lift up while doing push ups. \nIIRC: Knee push ups had a smaller percentage, meaning you were pushing up less weight. \n\nEdit: Provided by u/crnaruka\n\n“Your question made me curious and a quick search yielded the study linked below, which looked at exactly this question. The researchers found that the answer depends both on the variant of the exercise as well as the stage of the exercise. For example, in a traditional push-up the number is about 69% in the up position (at the top of the movement) and 75% in the down position (bottom of the movement).\n\nIt's also worth mentioning that the study also looked at a \"modified push-up.\" This modification [as shown here](_URL_0_) is essentially just an lazier easier version of the exercise where the knees stay on the floor. Surprisingly (to me at least), even in this simpler version you still lift quite a bit of your body mass (54% in the up position and 62% in the down position).\n\n[Link](_URL_1_)”\n\nFormatting is shitttt, I’m on mobile ):\n",
"Think about a spanner. It is much easier to turn a nut if you pull on the spanner at the far end, rather than near the nut. Forces which cause rotational motion are called moments (also called torques), and the distance from the point of rotation matters.\n\nNow when you do a push up the man way (from the feet), your centre of mass is further away from the pivot (your feet) than it is for girl push ups (from the knees). This means gravity induces a stronger moment on your body when doing a man-pushup, hence it is harder to fight against it and \"do\" the pushup.\n\nWhen going from the knees, you have shortened the distance between your centre of mass and the pivot, which weakens gravities' moment on your body, which means you have less resistance to pushup against."
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||
1zajee | If the gravitational force is transmited at the speed of light, does the earth orbit a 8-minutes-before sun? | 'Seen' from the center of the galaxy or any other outter reference frame. | askscience | http://www.reddit.com/r/askscience/comments/1zajee/if_the_gravitational_force_is_transmited_at_the/ | {
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"There's a subtlety: the gravitational field of the sun is retarded by 8 minutes, but it also encodes information about the sun's velocity, so the Earth is actually orbiting where the sun is \"now.\"\n\n_URL_0_",
"Questions like this are why it doesn't make sense to speak of simultaneity over relativistic distances. For all intents and purposes, where we see the sun right now is where it is, right now. Information about anything it might be doing differently (location, velocity, brightness, etc) won't reach us for 8 minutes, no matter what.\n\nThis is what relativity is all about. Every reference frame is valid and accurate and correct. Even when they contradict. _Especially_ when they contradict. There is no absolute vantage point, there is no privileged frame of reference, there is no referee to declare that events A and B (who are outside of each other's light cones) happened in _this_ order, because there's always someone who can claim differently and prove it."
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37xygt | In Gibbon's The Decline and Fall of the Romans Empire he calculates the population of the Romans world at the time of Claudius to be 120 million people. How accurate is this estimate? | In chapter two, Gibbon mentions that Claudius exercised a census of Roman citizens and extrapolates from there. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/37xygt/in_gibbons_the_decline_and_fall_of_the_romans/ | {
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"I do not know if he is correct but we must remember that a census of Roman citizens would only include a fraction of the population since a large portion of population were not actually considered citizens."
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[]
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