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How far do slugs travel?	Based on a quick google search, a slug can travel .013 meters per second, and typically lives for 18 months. At this rate if it slept 1/3rd of it's life (based on snail numbers, didn't see anything in 5 seconds of searching around for slugs), it would travel a maximum total of 254 miles in it's lifetime. Slugs like t...	[ "These sea slugs sometimes occur in abundant numbers during breeding time, swarming with over 1,000 individuals per square metre, as has been observed on numerous occasions. These swarms are all oriented in the same direction, determined by the flow of the tide. They follow each other at the same speed, forming col...
one of the primary enemies of nazis were communists. so why did stalin ever make a pact with hitler in the first place?	The pact wasn't an alliance. It was a non-aggression pact, so that each would keep out of the other's business. It didn't work.	[ "As Stalinism came to dominate the Comintern, the united front strategy was dropped. In the period preceding Adolf Hitler's electoral victory in Germany, the Comintern argued that the social democrats were \"social fascists\" and that they, rather than the Nazis, represented the real danger. Following Hitler's vict...
how to buy stocks(from a company)?	You can buy stocks from any brokerage, some of the bigger national ones are Charles Schwab, etrade, Scottrade, Morgan Stanley, and even many of the major retail banks. I think at your current knowledge level, you should consider buying index mutual funds, instead of trying to day-trade stocks, or other more advanced ...	[ "There are other ways of buying stock besides through a broker. One way is directly from the company itself. If at least one share is owned, most companies will allow the purchase of shares directly from the company through their investor relations departments. However, the initial share of stock in the company wil...
Is this a meteorite? (Here are pictures and surface x-ray results)	The high ferrite composition and the mix of some heavier elements(though in fewer percentages) would lead one to believe it might be a meteorite. The resource places are going to do the exact same thing you did. They're gonna use probably a higher end x-ray spectrograph and get more accurate results. Your best bet is t...	[ "Caroline Smith, meteorite curator at the Natural History Museum in London, stated that the pictures and video footage of the burning crater indicated that it was not a meteorite crater: meteorites are not aflame when they strike Earth. Smith also pointed out that there were no other reported sightings of any fireb...
what is that bright halo around light that we always see?	You have two components in your eyes that actually "see". They are called "Rods" and "Cones". "Rods" are spread throughout your retina while "Cones" are almost exclusively found in your Fovea (the middle of your visible range where there is a dense cluster of cones). The perception of these different components actuall...	[ "In optics, the Arago spot, Poisson spot, or Fresnel bright spot is a bright point that appears at the center of a circular object's shadow due to Fresnel diffraction. This spot played an important role in the discovery of the wave nature of light and is a common way to demonstrate that light behaves as a wave (for...
el15: how many fps does the human eye see?	This article goes into great detail about how the human eye interprets movies and the real world. _URL_0_ For those that don't want to read, this quote pretty much sums it up. " Seeing framewise is simply not the way how the eye\brain system works. It works with a continuous flow of light\information." An example t...	[ "The human eye can detect a luminance range of 10, or one hundred trillion (100,000,000,000,000) (about 46.5 f-stops), from 10 cd/m, or one millionth (0.000001) of a candela per square meter to 10 cd/m or one hundred million (100,000,000) candelas per square meter. This range does not include looking at the midday ...
Why doesn't all the hydrogen in the sun undergo fusion simultaneously?	When two hydrogen nuclei (protons) managed to slam together hard enough to fuse, they form a "diproton" (effectively a Helium-2 nucleus). This is a hideously unstable particle, and the vast majority of them simply immediately decay back into two protons, to no net effect. The tiny fraction that instead decay into deu...	[ "Because lithium-8 and beryllium-12 form natural stopping points on the table of isotopes for hydrogen fusion, it is believed that all of the higher elements are formed in very hot stars where higher orders of fusion predominate. A star like the Sun produces energy by the fusion of simple H-1 into helium-4 through ...
why do fat/obese/overweight people generally have a lot of strength even if they do not work out?	They gotta carry their fat ass everywhere they go	[ "Obesity induced from lack of exercise also contributes to a decrease in general mental health. Overweight children and teens are more likely to suffer from poor self-esteem, negative body image, teasing, and bullying.\n", "Obesity is a physical marker of poor health, increasing the likelihood of various diseases...
if a 5 year old were to fall into a coma and wake up 20 years later, how would they act?	Probably like a two year old. You don't spend 15 years in a coma and come back without some severe mental deficits.	[ "People may emerge from a coma with a combination of physical, intellectual, and psychological difficulties that need special attention. It is common for coma patients to awaken in a profound state of confusion and suffer from dysarthria, the inability to articulate any speech. Recovery usually occurs gradually. In...
Who actually wrote the Magna Carta?	I was going to summarise [this lecture](_URL_1_) from May but fortunately _URL_2_ has it online! The person giving this paper is one of the leads on the AHRC-funded [Magna Carta Project](_URL_0_), which represents the culmination of several years of study by scholars from the University of Easy Anglia and Kings College...	[ "Magna Carta is an English charter originally issued in 1215 which influenced the development of the common law and many later constitutional documents, such as the 1689 English Bill of Rights, the 1789 United States Constitution, and the 1791 United States Bill of Rights. \n", "\"1215: The Year of Magna Carta\" ...
Magnitude or depth, which is more important to strength of an earthquake?	In terms of perceived strength at a location (i.e. the [intensity of an earthquake](_URL_1_)), both the depth and magnitude will matter, as will horizontal distance from the epicenter (this together with depth will determine how far seismic waves have had to travel to reach your location and generally waves attenuate w...	[ "In seismology, the depth of focus or focal depth refers to the depth at which an earthquake occurs. Earthquakes occurring at a depth of less than are classified as shallow-focus earthquakes, while those with a focal depth between and are commonly termed mid-focus or intermediate-depth earthquakes. In subduction zo...
Baltic and North Seas meet but don't mix because of the differing density. Is a difference in density sufficient to cause immiscibility?	They may have a boundary like that but diffusion happens between the two bodies. It is not correct to think they wall each other off. Keep in mind that this is a surface picture only.	[ "The Baltic Sea's salinity is much lower than that of ocean water (which averages 3.5%), as a result of abundant freshwater runoff from the surrounding land (rivers, streams and alike), combined with the shallowness of the sea itself; runoff contributes roughly one-fortieth its total volume per year, as the volume ...
how does pi contain every word or combination of words?	This is a common misconception. Pi is an irrational number. Irrational numbers are numbers that can't be expressed as a quotient of two whole numbers. One minor property of irrational numbers is that when you try to write them as decimal fractions, you get an infinite and non-repeating sequence of digits. There are a...	[ "Mnemonic phrases or poems can be used to encode numeric sequences by various methods, one common one is to create a new phrase in which the number of letters in each word represents the according digit of pi. For example, the first 15 digits of the mathematical constant pi (3.14159265358979) can be encoded as \"No...
how can someone with a peanut allergy develop a semi-immunity to peanuts?	Immunotherapy has been applied to many allergies, yes. There's two general competing mechanisms that drive allergy. The first is what you could call the "pro atopic" side. This is the allergic response, and in these types of allergies it is mediated by a class of antibody called IgE. To simplify it a lot, more IgE ...	[ "Peanut allergy is a type of food allergy to peanuts. It is different from tree nut allergies. Physical symptoms of allergic reaction can include itchiness, hives, swelling, eczema, sneezing, asthma, abdominal pain, drop in blood pressure, diarrhea, and cardiac arrest. Anaphylaxis may occur.\n", "The clinical tri...
why after staring for too long into a light source (i.e. the traffic light), that pattern gets burned onto our sight?	Im no expert but I think this is because the cones/rods which sense light in our eyes "adapt" when exposed to light and become less activated so when you look away it takes some time to adapt again and you see a negative of that image for a while afterwards	[ "Some witnesses describe the light as appearing to approach them several times before retreating. Others report that the lights were able to keep pace with them when they were in a moving motor vehicle.\n", "A 1972 article in the \"Wilmington Star-News\" argued that \"most investigators\" had believed the light w...
Recycling of International Space Station?	To move anything from Earth orbit to Lunar orbit, you need about three times its mass as propellant. To do that for the entire space station, that would mean about 1,350,000 kg of propellant. To get all that to low Earth orbit, would mean about 11 Saturn V launches, or double that for Falcon Heavy. As to why small pie...	[ "The crew continued the task of building and enhancing the International Space Station by delivering the U.S. Destiny Laboratory Module. It was the first NASA lab to be permanently used ever since the days of Skylab nearly three decades earlier. It was manufactured by Boeing at the Michoud Assembly Facility and the...
how are the red blood cells separated from your blood during platelet donation?	If you want to separate something like blood that's made of water and different types of cells, you put it in a centrifuge, which is a machine that simply spins a hollow drum with test tubes in it *really, really* fast. As you spin the drum, the red stuff is forced to the bottom of the tube since it's heaviest, t...	[ "Donated blood is usually subjected to processing after it is collected, to make it suitable for use in specific patient populations. Collected blood is then separated into blood components by centrifugation: red blood cells, plasma, platelets, albumin protein, clotting factor concentrates, cryoprecipitate, fibrino...
why are things cheaper in the countryside?	MUCH cheaper land. Other things may be less expensive (like fruit and meat if you're in a farming area), and some things may be more expensive (like electricity, internet access, and utilities). However, anything you're buying locally has to have a store, and for most stores, rent and property taxes is one of their l...	[ "Smaller communities have fewer choices in food retailers. Resident small grocers struggle to be profitable partly due to low sales numbers, which make it difficult to meet wholesale food suppliers' minimum purchasing requirements. The lack of competition and sales volume can result in higher food costs. For exampl...
Accessible Viking Primary Sources	So the problem with the "from the Viking's perspective" part is that they were pre-literate during much if what we call the "Viking Age" (c.800-c. 1050). All of the sources from this time period are thus written by Anglo-Saxons, Franks, Arabs, etc. The sagas and later stuff are all pretty far removed from the period ...	[ "Modern scholars consider \"Cogad Gáedel re Gallaib\" to be a piece of \"brilliant propaganda\" written in a \"bombastic style and full of patriotic hyperbole.\" Although the chronicle remains a valuable source of information about the Viking Age in Ireland, its accuracy is uncertain.\n", "Information about the V...
can the shape of earbuds damage your ears/hearing.	It could if you decide to jam something that does not fit into your ear. Imagine a ten centimeter diameter hole in piece of paper, now imagine trying to fit a 20cm diameter rod through that same hole, it's going to rip the hole if forced through. TLDR: one size does not fit all and its up to the user to realise this...	[ "Dysfunction of the three small bones of the middle ear – malleus, incus, and stapes – may cause conductive hearing loss. The mobility of the ossicles may be impaired for different reasons including a boney disorder of the ossicles called otosclerosis and disruption of the ossicular chain due to trauma, infection o...
Why do our mouths fill with saliva right before we vomit?	To protect your teeth from stomach acid, which essentially turns your enamel into gum. This is also why you shouldn't brush your teeth directly after, and not at all if you don't have fluoride mouthwash to use prior to brushing.	[ "Saliva contains digestive enzymes called amylase, and lingual lipase, secreted by the salivary glands and serous glands on the tongue. The enzymes start to break down the food in the mouth. Chewing, in which the food is mixed with saliva, begins the mechanical process of digestion. This produces a bolus which can ...
why do i still need the disk for ps3 games after it's 'installed'?	Because it's not the entire game being installed. Some games have a pre-install to store information on your PS3 so loading times in-game will be kept to a minimum. If they were installing the entire game to your PS3's hard drive then you would run out of space after the first game.	[ "The Linux Kit turns the PlayStation 2 into a full-fledged computer system, but it does not allow for use of the DVD-ROM drive except to read PS1 and PS2 discs due to piracy concerns by Sony. Although the HDD included with the Linux Kit is not compatible with PlayStation 2 games, reformatting the HDD with the utili...
if a "double-yolk" egg was fertilized, would it, hypothetically, hatch 2 chiclets? what about a triple-yolk?	It depends on if there was a bird embryo on each yolk. The babby chicken is the little white (or red) goopy wisp thing you see on the yolk. The yolk is just the chick's food supply.	[ "In normal monozygotic twin development, one egg is fertilized by a single sperm. The egg will then completely split into two, normally at the two-cell stage. If the egg splits in the early blastocyst stage, two inner cell masses will be present, eventually leading to the twins sharing the same chorion and placenta...
can dogs understand other dogs when they bark?	Dogs don't bark in a language like how you speak English. Languages are an invention which must be taught to our children and requires constant care and revision to be mutually intelligible. Dog barks are extremely simple vocalizations. Though it is probable that dogs have a better idea of why another dog is barking t...	[ "Stanley Coren identifies 56 signals which untrained dogs make and people can understand, including 10 barks, 5 growls, 8 other vocalizations, 11 tail signals, 5 ear and eye positions, 5 mouth signals and 12 body positions. Faragó et al. describe research that humans can accurately categorize barks from unseen dogs...
what was the purpose of the holocaust? why did hitler want to kill millions of people, and how did he select the ethnic/minority groups?	He saw the "Aryan" race as superior, which was essentially Caucasian and strictly not Jewish. He wanted to wipe out all "undesirables". This didn't entail Jews alone. He sought to wipe out Roma and Sinti people, homosexuals, political enemies such as communists, and only wanted chosen individuals within the Aryan race ...	[ "The military campaign to remove certain classes of persons (above all, Jews) from Germany and other German-held territories during World War II, often with extreme brutality, is known as the Holocaust. It was carried out primarily by German forces and collaborators, German and non-German. Early in the war, million...
Why can a rocket fly straight up without wings and doesn't tip over?	Large commercial rockets are actively steered. Either the engines are 'gimbaled' (the angle is adjusted) constantly, or small sideways-pointed rockets are fired as needed, to push the rocket where the computer is programmed to send it. Smaller rockets without adjustable engines or controls normally cause the rocket to...	[ "Another problem in this maneuver is that higher lift from the faster moving outside wing will roll the airplane to the left (or to the right). Most pilots find holding forward right (or left) stick necessary throughout the pivot.\n", "If the engine kept pushing the nose straight up even as the rest of the rocket...
Were the German bunkers on Omaha beach much further from the shire than popularly dramatised in thr film Saving Private Ryan?	One of the historical 'inaccuracies' about Saving Private Ryan is that the film does shorten the beach considerably. Omaha Beach has a very shallow slope and the distance between the low tide and high tide marks can be as much as 400-500m. The landings were timed to start at low tide in order that the various beach obs...	[ "Midway between the old harbour and the camping ground an old German bunker, constructed around the time of World War I, appears on the beach. During World War I, it formed part of \"Sicherungsstellung Nord\", a German line of 900 bunkers spanning the region of Sønderjylland, constructed to halt an eventual English...
how does an automated check-out tell the difference between the different notes (eg: £5, £10, £20) and different coins? how does it tell these from regular paper (notes) or items of a similar shape/weight (coins)?	_URL_0_ Notes are scanned and matched up to images stored in the software, which also checks for some security features. If you produce a sufficiently good fake, it will be accepted, but it would be easier to pass it to a human. Coins fall into slots which are the correct sizes. The slots have valves which only open ...	[ "Electronic counting systems, with no moving parts, exist that count both notes and coins on the same machine and sum the value of all denominations counted. They are normally used to count individual deposits or the content of cash drawers and do not sort or check for counterfeit or damaged notes.The machine uses ...
Has any other ancient civilization/Empire other than from India come up with the Philosophy of Nonviolence?	Gandhi's own belief in non-violence was strongly influenced by Leo Tolstoy's, expressed in his book The Kingdom of God is Within You, whose pacifism is credited to his religious views as a Christian. Tolstoy wrote in A Confession, The Gospels in Brief, and What I Believe: > The passage which served me as key to th...	[ "The political philosophy most closely associated with modern India is the one of ahimsa (non-violence) and Satyagraha, popularised by Mahatma Gandhi during the Indian struggle for independence. In turn it influenced the later movements for independence and civil rights, especially those led by Martin Luther King, ...
Why is the ethnic majority of China referred to as "Han Chinese"?	You're right in thinking that the Han was a dynasty of China. It lasted from 206BCE to 220CE, and was an incredibly important dynasty in Chinese history in terms of scientific, cultural and political developments. Think of it as the Classical Chinese period. The reason that we talk about 'Han Chinese' is because of th...	[ "11 - 92% of the Chinese believe that they are of one race, the Han Chinese, unlike the other most populous nations such as India, the United States, Brazil, Indonesia and Turkey which recognize themselves to be highly multi-racial and multi-cultural\n", "Han Chinese people, the largest ethnic group in China, are...
Hi Reddit! How fast can the effects of gravity be felt? I don't really know how to word this, check out the text for further description.	Gravitational waves would travel at the speed of light, so we'd move normally for about eight minutes.	[ "Critical response for Professor Heinz Wolff's Gravity has generally been lukewarm, receiving an overall score of 63 on Metacritic. The website IGN awarded it 59 out of 100, citing it had potential to be a sleeper hit, but was too light on content for the price tag.\n", "The effects for negative g-force can be mo...
Does covering your mouth when you sneeze/cough actually help prevent the spread of disease?	Yes it does; [while not the best scientific source, a good visual representation](_URL_0_)	[ "Prevention is by not smoking and avoiding other lung irritants. Frequent hand washing and flu vaccination may also be protective. Treatment of acute bronchitis typically involves rest, paracetamol (acetaminophen), and NSAIDs to help with the fever. Cough medicine has little support for its use and is not recommend...
Why did we have to send a probe to Pluto to get a photo of it?	The photo of the black hole is not a "photo" in the sense you are thinking. It is a visualization of very high-frequency radio waves. While these are still electromagnetic waves just like visible light, they are way outside of our visible range. This is necessary to "penetrate" through all of the super-heated matter th...	[ "In July 2015 NASA published photographs taken as the New Horizons space probe passed within 7000 miles of Pluto. A photo of Pluto's largest moon, Charon, shows a large dark area near its north pole. The dark area has been unofficially called Mordor Macula.\n", "On February 12, 2015, NASA released new images of P...
how do programs like ccleaner clean the windows registry?	Registry cleaners are pretty much useless these days, as Windows is pretty good about keeping the registry clean itself. Regardless, cleaning the registry doesn't really result in much of a performance impact. One of the big things that registry cleaning does is remove entries that refer to files/folders that no longe...	[ "Most Windows applications still store their user settings in individual .ini (initialization) files spread across the disk. They additionally use the Windows Registry to store information which might be of interest for other software. For such programs the Windows Registry acts rather as a bulletin board, than as ...
I've just read a very short article about Old French Sign Language. What we do know of deaf life, culture and community in 18th century Paris? How was deafness depicted in general in France in this period?	Do you have a link to the article?	[ "In France, the first sign languages developed in the 18th century. Old French Sign Language was used in Paris' deaf community, before l'Abbé Charles Michel de l'Épée started his deaf school in 1760 in Paris. L'Épée's lessons were based upon his observations of deaf people signing with hands in the streets of Paris...
Someone told me it was "too cold to snow". How?	The amount of moisture in the air is dependent upon its temperature, below a certain point there is too little moisture for precipitation. There are various large stretches of the Antarctic that qualify as deserts because they have so little precipitation due to this principle. But -2 is certainly warm enough to snow....	[ "After a successful trial with Norwegian club Bodø/Glimt he joined them on initially on loan in 2012. Having moved from Senegal to the Arctic Circle, Ndiaye admitted it was a culture shock.—\"When I got up on the first day and opened the front door I was terrified. I had never seen snow before, or at least only on ...
what keeps movies unreleased? what stops any movie studio employee from just downloading a movie that hasn’t come out and leaking it to the internet?	Because theft and distribution are crimes. People aren't keen on having their lives ruined to show off some movie.	[ "\"There are websites that provide legal downloads. This is not one of them. This website has been permanently shut down by court order because it facilitates the illegal downloading of copyrighted motion pictures. The illegal downloading of motion pictures robs thousands of honest, hard-working people of their liv...
how is it that the mars curiosity rover is able to go years without fuel/recharging and how are we able to send such a strong signal?	Curiosity, the MSL rover that was successfully landed in Gale Crater on August 6, 2012, uses one MMRTG to supply heat and electricity for its components and science instruments. Reliable power from the MMRTG will allow it to operate for several years. In February 20, 2015, a NASA official reported that there is enough ...	[ "When fully illuminated, the rover triplejunction solar arrays generate about 140 watts for up to four hours per Martian day (sol). The rover needs about 100 watts to drive. Its power system includes two rechargeable lithium ion batteries weighing each, that provide energy when the sun is not shining, especially at...
We all hear about species being extinct. But how often does a new species "evolve" into a new one?	[This article](_URL_0_) (PDF) seems to put it at about 3 new species per year but it is very debatable. Speciation may occur in burst and there are many other factors. Hopefully someone else can dig up more information.	[ "If a population cannot move or change sufficiently to preserve its long-term viability, then obviously, it will become extinct, at least in that locale. The species may or may not survive in other locales. Species extinction occurs when the death rate over the entire species exceeds the birth rate for a long enoug...
why do i get sleepy when i get nervous?	You might have some kind of chemical imbalance, disease, or infection. You should get that checked out. There isn't really an ELI5 answer to this.	[ "Seriously anxious people find it difficult to control their worry and typically experience symptoms like Restlessness, Fatigue, Difficulty in concentrating, Irritability, Muscle tension and Sleep disturbance.\n", "According to the American Academy of Sleep Medicine there is a wide range of potential causes, incl...
how come chinese words in english are spelled funky?	Zhou is not pronounced like Joe. Chinese words are generally spelled according to their pinyin (phonetic system) which has correlates English letters to pronunciation.	[ "Foreign words, mainly proper nouns, continue to enter the Chinese language by transcription according to their pronunciations. This is done by employing Chinese characters with similar pronunciations. For example, \"Israel\" becomes \"Yǐsèliè\", \"Paris\" becomes \"Bālí\". A rather small number of direct translite...
During the California gold rush why didn't the American government at the time leave it for other immigrants	The gold of the California gold fields - as it was understood in 1849 and the early 1850s - was an extensive resource, meaning that it was broadly distributed in small amounts. It took tens of thousands of people to process hundreds of thousands of tons of dirt to find the gold they were seeking, and at that, $4 - roug...	[ "In January 1848, two weeks after California was ceded to the United States, gold was discovered in California, resulting in a flood of fortune seekers gravitating to the state in the following months and years. Due to the ambiguity of existing laws regarding squatting on federal land, individual mining camps devel...
Were there any European explorers prior to 1700 who attempted to cross the pacific ocean from Asia?	If you are asking if Europeans had been crossing the Pacific before 1741, the answer is a *clear yes*. Magellan's expedition in 1519-1522 was the first to cross the Pacific in from east to west direction, going from Magellan's straits to Phillipines. And it was followed up by many more till 1741 If you are askin...	[ "In 1519, an expedition sent by the Spanish Crown to find a way to Asia was led by the experienced Portuguese navigator Ferdinand Magellan. The fleet explored the rivers and bays as it charted the South American coast until it found a way to the Pacific Ocean through the Strait of Magellan.\n", "In the second hal...
How important was the Act of Union (1707) to the growth of the already existing English empire? Would England itself have had a comparable empire in size to the British Empire had it not formed the Kingdom of Great Britain with Scotland?	This question would be better suited to /r/HistoricalWhatIf	[ "In 1707, the Acts of Union received their Royal assent, thereby abolishing the Kingdom of England and the Kingdom of Scotland and their respective parliaments to create a unified Kingdom of Great Britain with a single Parliament of Great Britain. Anne formally became the first occupant of the unified British thron...
what can someone do if they have your ip address? can they see all your internet activity and places you've posted? can they identify who you are?	If they only had your actual IP address, they could DDOS you and potentially locate you within a rough geographic area. But that's about it. If they had your IP but also purchased or collected date from cookies and such, they could learn a lot more.	[ "In 2010 the Federal Supreme Court of Switzerland found that IP addresses are personal information and that under Swiss privacy laws they may not be used to track Internet usage without the knowledge of the individuals involved.\n", "Finding \"relevant\" and \"reachable\" IP addresses is the objective of the reco...
why does 'latin' mean hispanic?	Likewise, Hispanic means you're from Hispania, or Spain. It doesn't really make sense to call someone from say, Venezula an Hispanic, even if they speak Spanish. That's like saying someone from Minnesota is English. Regardless, Hispanic is still used that way.	[ "Though often used interchangeably in American English, \"Hispanic\" and \"Latino\" are not identical terms, and in certain contexts the choice between them can be significant. \"Hispanic\", from the Latin word for \"Spain,\" has the broader reference, potentially encompassing all Spanish-speaking peoples in both h...
Why does my skin look different under different lighting conditions?	Different kinds of lights are composed of different wavelengths of light. That is some lights have more red others more blue etc. When these reflect off your skin which reflects different colors differently you get different colors. It has nothing to do with x-rays.	[ "Skin-lightening products are still prevalent in many parts of the world. This may be due to aesthetic or social-standing reasons, in areas where a lighter skin tone is considered to be a sign of wealth or beauty.\n", "Often restaurants, bars and other social gathering places will dim lighting to maximise amber s...
if the polar ice caps were developed during the last ice age, why is it so bad that they are melting now? isn’t that more of a return to where we were rather than an anomaly?	The earth doesn't give a shit what's happening to it. You do along with all the things that live on it because they've adapted to the conditions that existed after the last ice age and they don't want to adapt again to rapidly changing conditions because that means a lot of them and their offspring are going to die.	[ "Earth's polar caps have changed dramatically over the last 12,000 years. Seasonal variations of the ice caps takes place due to varied solar energy absorption as the planet or moon revolves around the Sun. Additionally, in geologic time scales, the ice caps may grow or shrink due to climate variation. If the polar...
With the massive influx of gold miners immigrating to California during its gold rush, was there enough food and water grown locally for them? Was food sent in? The miners obviously weren’t growing their own food.	Water was usually not a problem - the California Gold Country has plenty of streams and rivers. During the drier times, miners had to wait for enough flow to "wash dirt" - the method used to expose gold, but there was always enough to drink. Miners spent a lot of time hunting. I co-edited the [letters of the Grosh Bro...	[ "During the California Gold Rush there were many new immigrants who were familiar with fishing. There was a large demand for fresh food including fresh fish and shellfish among the rapidly increasing California population. Providing fresh food products were one of the most wanted and lucrative trades that developed...
How have the eyes of animals that need clear vision in and out of water evolved to cope with the varying refractive indices?	Anableps fish just have eyes that are half-and-half divided, with the top half working well out of water and the bottom working well in. It's _weird_. Seal pupils contract in the bright light of the surface, and their eyes focus better in air. In dim light (like they experience underwater) the pupils expand and th...	[ "Aquatic animals must rely entirely on their lens for both focusing and to provide almost the entire refractive power of the eye as the water-cornea interface does not have a large enough difference in indices of refraction to provide significant refractive power. As such, lenses in aquatic eyes tend to be much rou...
why, when most people orgasm, they instinctively want to vocalize their excitement/expressions?	No scientific answer here, but I can only assume it is like any other "unexpected" rush of emotions or feeling. When you step on a nail, you shriek. When you burn your hand, you shriek. Just like anonoman925 said, it is probably an involuntary reaction to too much stimulus. TL;DR: Too much stimulus = Involuntary react...	[ "Normally, a human being is able to feel pleasure from an orgasm. Upon reaching a climax, chemicals are released in the brain and motor signals are activated that will cause quick cycles of muscle contraction in the corresponding areas of both males and females. Sometimes, these signals can cause other involuntary ...
What would happen if a MAGLEV train lost power?	They have wheels.	[ "The train started moving at 09:53. 57seconds later emergency braking was recorded. Approximately half a second and 25metres later the maglev train hit the maintenance vehicle at a speed of 162km/h. The aerodynamic design of the transrapid caused it to dive under the heavy (60 tonne) maintenance vehicle, ripping of...
how would the space agencies respond if they detect an incoming asteroid large enough to cause damages?	The space agencies would report it to the public. They are in no position to keep anything like that a secret and in no position to do anything about it. The only thing they can do is warn people the best they can in the hopes that people might get to safety. The only thing anyone might be able to do about it is to lau...	[ "Sub-150m impacting asteroids would not cause global damage but are still locally catastrophic. They can, by contrast to larger ones, only be detected when they come very close to the Earth, which in most cases only happens during their final approach. Those impacts therefore will always need a constant watch and t...
how are news outlets and online articles able to be so misleading and sometimes downright wrong with their stories?	Back up a bit and imagine a government body who's job is to decide what is and isn't true, and to censor or fine news agencies that it believes are wrong. A) It would be incredibly unconstitutional, as freedom of the press is a critical right that we all have. B) Consider the possibility of abuse. Is it staffed by ...	[ "Because news organizations and websites hotly compete for viewers, there is a need for great efficiency in releasing stories to the public. News media companies broadcast stories 24 hours a day, and break the latest news in hopes of taking audience share from their competitors. News is also produced at a pace that...
why do injuries tend to hurt more in winter than in summer?	Generally speaking, we feel more pain in the cold because there is a relationship between blood circulation and nerve pain. When its cold outside and you aren’t dressed up for it, it’s very difficult for your body to heat itself because your heart rate slows in the cold as a way to survive. Our nerves are a network tha...	[ "During the summer rains are common in the late afternoon. Temperatures at this time are always very high. In the winter the arrival of polar air masses that drop and cause frost. In this time of year the relative humidity is too low, and causes discomfort to the population.\n", "Rising temperatures have two oppo...
How can moons get "captured" by planetary bodies without having done a "retrograde burn"?	Triton is Neptune's captured moon. To go into orbit, Triton still had to lose momentum somehow, just as you do a burn to get captured by Duna (or, perhaps get your orbit adjusted by Ike). In KSP, the moons and planets are all on rails, but in real space, you would transfer some of your momentum to Ike to get captured b...	[ "The mission to Meta is postponed when the crew seemingly contract a virus, later dying on (although the cause of death is subsequently revealed to be \"magnetic radiation\" emanating from nuclear waste disposal areas on the Moon's far side). With the arrival of a back-up crew, preparations for launch resume, but b...
How did the Merchant Republics in Italy arise in isolation while the rest of Europe seems steeped in Feudalism?	I'm not sure the question as it's posed will yield a satisfactory answer. Feudalism and a republic aren't mutually exclusive, as the former isn't a type of government. Besides, the republics present in Italy weren't the kinds of republics we think of today. They were essentially city-states dominated by elites and r...	[ "During the Early Middle Ages, Italy endured sociopolitical collapse and barbarian invasions, but by the 11th century, numerous rival city-states and maritime republics, mainly in the northern and central regions of Italy, rose to great prosperity through trade, commerce and banking, laying the groundwork for moder...
what causes that characteristic "grandma scent?"	technically it's described as: * floral * aldehydic (a sub category of floral, think soapy and citrusy) * musky * powdery To ELI5, it's typically Chanel No 5 with a slight baby powder note.	[ "Phantosmia (olfactory hallucinations), smelling an odor that is not actually there, and parosmia (olfactory illusions), inhaling a real odor but perceiving it as different scent than remembered, are distortions to the sense of smell (olfactory system) that, in most cases, are not caused by anything serious and usu...
what would happen if you took laxatives for an entire week?	Former laxative abuser here. Assuming you are talking about stimulant laxatives, while continuing a normal diet, the only weight loss would come from holding less waste in your body and dehydration, as your body still digests the food normally. You may experience severe muscle cramps, intestinal bloating from inflammat...	[ "Methods of prevention include gradually decreasing the dose among those who wish to stop, though it is possible for symptoms to occur with tapering. Treatment may include restarting the medication and slowly decreasing the dose. People may also be switched to the long acting antidepressant fluoxetine which can the...
if we can't see atoms how did ibm make a movie with them?	Those are Carbon Monoxide molecules. For that note, electron microscopes can operate pretty much on an atomic scale.	[ "Scientists at IBM used a scanning tunneling microscope to single out and move individual atoms which were used to make characters in \"A Boy and His Atom\". This was the tiniest scale stop-motion video made at that time.\n", "In 1980, he produced \"The Atomic Alphabet\" – a giant, poster-sized hand-colored litho...
were little old people always little or do they shrink as they age?	Most people do shrink as they get older and their bodies degenerate. The very little old people you're thinking of were short to begin with and shrivel up more.	[ "Depending on sex, genetic and environmental factors, shrinkage of stature may begin in middle age in some individuals but tends to be universal in the extremely aged. This decrease in height is due to such factors as decreased height of inter-vertebral discs because of desiccation, atrophy of soft tissues and post...
Why do some places show a long-term decline in sea level and others a rise?	Measuring sea level is actually tricky business and we're not really that good at it currently. Additionally, there's global sea level and local sea level. Global sea level is mostly affected (at least on human time scales) by the volume and temperature of the ocean (which is mostly affected by melting of surface ic...	[ "Superimposed on the global rise in sea level, is strong regional and decadal variability which may cause sea level along a particular coastline to decline with time (for example along the Canadian eastern seaboard), or to rise faster than the global average. Regions that have shown a rapid rise in sea level during...
How do we measure gas levels of an exoplanet's atmosphere?	Molecules have characteristic absorption lines in the electromagnetic spectrum. The width of these absorption lines depends on the optical thickness of the gas. Meaning, with more gas in our line of sight we will have a stronger (wider) absorption band. In order to measure the atmosphere of a planet, the planet needs...	[ "The first exoplanet whose atmospheric composition was determined is HD 209458b, a gas giant with a close orbit around a star in the constellation Pegasus. Its atmosphere is heated to temperatures over 1,000 K, and is steadily escaping into space. Hydrogen, oxygen, carbon and sulfur have been detected in the planet...
Education in post war Germany?	> How valued were their qualifications? In West Germany the folks behind the racial science of the nazi regime [kept teaching their subjects](_URL_0_) using their skills to, for example, measure the skulls of the Canary Islanders. The continuity of West German elites would be a major issue both to East Germany and in...	[ "After the defeat in World War II, the Allied occupation government set education reform as one of its primary goals, to eradicate militarist teachings and convert Japan into a pacifist democracy. Nine years of education was made mandatory, with six years in elementary education and three in junior high as an emula...
Can house flies, fruit flies, or other insects see the microscopic organisms or bacteria on stuff that we can't see?	I don't believe they can. Their eyes, [compound eyes](_URL_1_), are not intended to see high detail images because their largest threats are larger than they are (ie, a cow's tail or your hand trying to swat them). Instead, they are intended to see fast movements over a large angular resolution, they can see movements ...	[ "BULLET::::- Insect stages - \"Some larvae, nymphs and adult insects that live in freshwater.\" \"A UK-based web site with microscopic photos of various insects and other microorganisms as well as biological information.\"\n", "Micro-animals are animals so small that they can be visually observed only under a mic...
why do some people enjoy massages but it causes pain for others?	There is a huge difference between massages just for the feeling of someone rubbing your back with some more force in it and massages for relaxing muscles. I have a rather high pain tolerance, but if my muscles are really tense, having them massaged hurts a lot. I can't give you a good explanation for that (any physi...	[ "People state that they use massage because they believe that it relieves pain from musculoskeletal injuries and other causes of pain, reduces stress and enhances relaxation, rehabilitates sports injuries, decreases feelings of anxiety and depression, and increases general well being.\n", "All types of massage, i...
When was the highest % of the global population enslaved and did ancient societies with more slaves have an economic advantage over their rivals?	Follow-up: Did areas with high percentages of slaves have poor freemen angry over economic woes? It seems like there would be a shortage of paying jobs when the wealthy could simply buy slaves to fill almost every role from farmhands to pedagogues.	[ "According to the \"Encyclopedia of African History\", \"It is estimated that by the 1890s the largest slave population of the world, about 2 million people, was concentrated in the territories of the Sokoto Caliphate. The use of slave labor was extensive, especially in agriculture.\" The Anti-Slavery Society estim...
why is it easy to pick up a child that weighs 40 to 50 kilograms but very difficult to pick up a 40 to 50 kilogram weight?	The weight of the child is spread out over a large area compared to the relatively small area of the weight, making the child appear easier because it uses more muscles.	[ "For instance, the factor \"153,552,935\" (5 turns around a capstan with a coefficient of friction of 0.6) means, in theory, that a newborn baby would be capable of holding (not moving) the weight of two supercarriers (97,000 tons each, but for the baby it would be only a little more than 1 kg). The large number of...
If an Amnesia victim has lost their memories for a significant amount of time and recovers their memories, will they regain their original personality or keep the amnesia personality?	What we observe as personality is the product of variance in regions of the brain- this study, for example, shows the correlation between neuroticism and amygdala variance- _URL_0_ . An individual's personality is quite stable over the long run- see here _URL_1_ and here _URL_2_ . Amnesia, specifically in your case r...	[ "The form of amnesia that is linked with recovered memories is dissociative amnesia (formerly known as psychogenic amnesia). This results from a psychological cause, not by direct damage to the brain, and is a loss of memory of significant personal information, usually about traumatic or extremely stressful events....
can alcohol turn you into a different person?	In my experience, alcohol just loosens inhibitions. So people who "get mean" when they drink are just mean people who usually keep it together. Just like I get really sentimental when I drink; I'm a sentimental guy, it's just normally under the surface.	[ "To produce a spiritual conversion necessary for sobriety and sanity, alcoholics needed to realize that they couldn't conquer alcoholism by themselves—that surrendering to a higher power and working with another alcoholic were required. Sober alcoholics could show drinking alcoholics that it was possible to enjoy l...
Like Google Maps...but for History	The website [GeoCron](_URL_1_) is a good place to start. You can skip to any year and it will show you roughly what the world looked like. It is not entirely accurate at some points, like sometimes the author just places a circle and the name of the civilization where he may not have much information. However, it is a ...	[ "BULLET::::4. Google Maps beginning as a \"thought bubble\" and a series of random scribbles on a white board in 2004 by Noel Gordon, one of the four men who founded the Sydney-based software company Where 2 Technologies. Google Earth developed separately in the US around the same time while Google Street View foll...
modulo	Mod is basically the remainder of a division problem. 50mod7 is 1 because 50/7 = 7 with a remainder of 1. 7*7 = 49. 49 + 1 = 50. 50mod7 = 1. 39mod5 = 4 100mod12 = 4 92mod3 = 2	[ "\"Modulo\" is mathematical jargon that was introduced into mathematics in the book \"Disquisitiones Arithmeticae\" by Carl Friedrich Gauss in 1801. Given the integers \"a\", \"b\" and \"n\", the expression \"a\" ≡ \"b\" (mod \"n\") (pronounced \"\"a\" is congruent to \"b\" modulo \"n\"\") means that \"a\" − \"b\" ...
Why have no new phyla developed since the Cambrian Explosion?	This is because of the way that phyla (and other taxonomic groups) are defined. Phyla are essentially arbitrarily-defined groups, and there is no particular amount of structural or genetic divergence that causes us to classify a particular group as a phylum. However, like other taxonomic groups, scientists do strive to...	[ "In the 1970s there was already a debate about whether the emergence of the modern phyla was \"explosive\" or gradual but hidden by the shortage of Precambrian animal fossils. A re-analysis of fossils from the Burgess Shale lagerstätte increased interest in the issue when it revealed animals, such as \"Opabinia\", ...
Before French and Latin, has there been any other lingua franca?	Greek! The Romans themselves were Grekophiles, and most well-educated Romans would be expected to know Greek. Greek was the lingua franca of the eastern Mediterranean (and was also widely spoken in many western mediteranean settlements like Massalia and Emporion) and continued to be the primary language of communicatio...	[ "The term \"lingua franca\" derives from Mediterranean Lingua Franca, the pidgin language that people around the Levant and the eastern Mediterranean Sea used as the main language of commerce and diplomacy from late medieval times, especially during the Renaissance era, to the 18th century. At that time, Italian-sp...
Why does it spread germs/illnesses to leave a bathroom with hands unwashed, yet oral-genital contact is not regarded as a surefire way to get the same illnesses?	Washing your hands after using the bathroom is not just about the germs gathered during the time using the bathroom. Ingraining that habit into people while they are at a sink with water gets them to clean away other germs they may have picked up without having to make a special trip to wash. Human fecal matter is th...	[ "General sanitary hygiene is the most important method of preventing sapovirus. This can be done by thoroughly washing hands after using the restroom and before eating/preparing food. Contaminated surfaces should be cleaned with disinfectant and or solutions containing bleach. Other preventative measures include av...
how can i invest and grow my money without knowing how to invest?	The market overall is down right now, so it makes sense that you lost some money. The three main things you need to know: Investment gains are slow; it wouldn't be a surprise for it to take a year or so before you make $10 on $500. The safest way to invest is to diversity; buying shares of an index fund or an ETF will ...	[ "By investing \"directly\" in an institution, rather than purchasing stock, an investor is able to create a greater social impact: money spent purchasing stock in the secondary market accrues to the stock's previous owner and may not generate social good, while money invested in a community institution is put to wo...
sound. yes i get that is a wave but how is a wave able to encode so much variety (voice, instruments, sound effects)?	If it were a single wave, it would not convey so much. But sounds like you describe are a series of waves, spread out over time and interpreted by an excellent computer -- your brain.	[ "Wave Sequences were first introduced on Korg's Wavestation synthesizer, released in 1990. Wave Sequences allow a single note to play through a list of samples, one after the other, with or without crossfades, with other associated parameters changing for each sample, as listed below. This can create smooth, evolvi...
Is this any intuitive way to think about normal distribution function ?	The gaussian distribution is e^-x^2. It is the heart to the shape that is called the normal distribution. The pis, the sigmas, the various other values are just adjustments. The constant term in front of the exponential is just a multiplier to make the area under the curve equivalent to 1 (so that the sum of the prob...	[ "In mathematics, a distribution function is a real function in measure theory. From every measure on the algebra of Borel sets of real numbers, a distribution function can be constructed, which reflects some of the properties of this measure. Distribution functions (in the sense of measure theory) are a generalizat...
This Week's Theme: The 14th Century, AD	Current: 14th Century AD On Deck: Resistance and Conformity In the Hole: Propaganda	[ "The 15th century is part of the High Middle Ages, the period from the coronation of Charlemagne in 800 to the close of the 15th century, which saw the fall of Constantinople (1453), the end of the Hundred Years War (1453), the discovery of the New World (1492), and thereafter the Protestant Reformation (1515). It ...
Do the descendants of the major Japanese clans (Tokugawa, Oda, etc) still have influence or command respect? Are their any clans that still 'exist', so to speak?	After the Meiji restoration, the clans were [converted into noble families](_URL_1_), along the lines of European nobility. Their domains were [converted into prefectures](_URL_0_), with a centralized authority, though they were allowed to keep 10% of the province's revenue. If you're interested in this time period, th...	[ "The was a powerful \"daimyō\" family of Japan. They nominally descended from Emperor Seiwa (850–880) and were a branch of the Minamoto clan (Seiwa Genji) by the Nitta clan. The early history of this clan remains a mystery. Members of the clan ruled Japan as \"shōguns\" from 1603 to 1867.\n", "The was a prominent...
Ionized water	Could you be more specific? In general, anyone claiming to make "ionized" water is running a scam, but depending on what device they're selling, it may produce any of a number of things.	[ "Although the exact ion formation mechanism is not clear, water can be ionized directly by Penning ionization. Another proposal is that water is ionized by the same mechanism that has been proposed for atmospheric pressure chemical ionization\n", "A water ionizer (also known as an alkaline ionizer) is a home appl...
why do i get these rashes on my throat after i've shaved?	A few years back I switched to a brush+lather shave and never looked back. Canned shave gel is total garbage. This made all the difference in the world to me. That and picking up a safety razor.	[ "After a hair has been shaved, it begins to grow back. Curly hair tends to curl into the skin instead of straight out the follicle, leading to an inflammation reaction. PFB can make the skin look itchy and red, and in some cases, it can even look like pimples. These inflamed papules or pustules can form especially ...
what is tickling? why do we have places like on our sides and armpits that makes us laugh out of panic when there is no real danger?	This is just a short explanation based on the video at the end of my comment: Small tickling (like from a feather) is called knismesis. It makes you scratch/touch places. This is to make us get rigd of insects, spiders and other stuff we don't want to have on our skin. Many animals are ticklish too so it shows us our ...	[ "A third, hybrid hypothesis, has suggested that tickling encourages the development of combat skills. Most tickling is done by parents, siblings and friends and is often a type of rough-and-tumble play, during which time children often develop defensive and combat moves. Although people generally make movements to ...
Why does some music just sound... Old? Is it recording quality, or were instruments constructed differently?	Can you shoot some examples of what recorded music you're thinking of?	[ "Vintage musical equipment is older music gear, including instruments, amplifiers and speakers, sound recording equipment and effects pedals, sought after, maintained and used by record producers, audio engineers and musicians who are interested in historical music genres. While any piece of equipment of sufficient...
why is nuclear fusion considered the "holy grail" of nuclear power compared to fission?	> but I fail to understand why fusion is safer Because it requires extremely specific circumstances to occur. The second those conditions are lost, the reaction can't physically happen. If you don't have enough heat in the system, the fuel won't have enough energy in it to fuse. > cleaner It doesn't use radioactiv...	[ "As a source of power, nuclear fusion is expected to have several theoretical advantages over fission. These include reduced radioactivity in operation and little high-level nuclear waste, ample fuel supplies, and increased safety. However, achieving the necessary temperature/pressure/duration combination has prove...
why are white americans not called european americans? similar to asian americans and african americans.	We should not use any of these segregating terms. We should simply use the term Americans instead.	[ "The term is used by some to emphasize the European cultural and geographical ancestral origins of Americans, in the same way as is done for African Americans and Asian Americans. A European American awareness is still notable because 90% of the respondents classified as white in the U.S. Census knew their European...
why were trains invented so much earlier than cars? it seems like trains would be harder to manufacture and create.	Imagine a car running a steam engine, burning coal in a furnace, using the heat to heat up water, pump that water, and turn the wheels. Also storage for coal to be able to go hundreds of miles. This is easier to go in a 200 tonne stab of metal than a tiny box with people inside. Also no need for steering, just tur...	[ "In the early 20th century, when automobiles were still new technology, their production levels were low enough that they could be shipped in sufficient quantities in boxcars. Two to four automobiles would usually fit into one boxcar. But as the automobile industry grew in size, railroads found that they needed to ...
what's the difference between cs (computer science), cis (computer information science, and it (information technology?	Computer Science : It’s the science (mathematics) of how computers inherently work. It would have an answer to this question: If I had a bunch of random numbers, what would be the fastest way to sort them, is it the fastest way? And why is it the fastest way. It often requires writing code but only to verify and qu...	[ "Information and computer science (ICS) or computer and information science (CIS) (plural forms, i.e., \"sciences\", may also be used) is a field that emphasizes \"both\" computing and informatics, upholding the strong association between the fields of information sciences and computer sciences and treating compute...
Historical Fencing in the US of A	Matthew J. O'Rourke, a captain of volunteers on the Union side during the Civil War, published a treatise on the use of the saber in 1872, which was adopted as the Army's standard. You can get a free ebook of the manual here: _URL_0_ The first half of the the book is "the Manual," regulations for how to draw a sword on...	[ "Many people self-identify as classical fencers, but do not share the concept of classical fencing described in this article, preferring the early to mid-20th-century style of competitive fencing (which, in the United States, was formalized and governed by the American Fencing League, or AFL) to the more classical ...
In high and late medieval Europe, German & Yiddish-speaking Jews had very high rates of literacy. However, was this isolated to Hebrew literature or could most Jewish people also read the Latin alphabet?	Gotz Aly (Why the Germans, why the Jews) explained that having extremely limited opportunities, European Jews invested heavily in and prioritized education. Whether their own religious education or secular education. As a result, they often had a mastery or at least understanding of multiple languages. Being persecute...	[ "By the Middle Ages, large numbers of Jews lived in the Holy Roman Empire and had assimilated into German culture, including many Jews who had previously assimilated into French culture and had spoken a mixed Judeo-French language. Upon assimilating into German culture, the Jewish German peoples incorporated major ...
what does the death of kim jong-il mean for north korea/the rest of the world?	It's very hard to say at this point. There is very little information out about Kim Jong-un and we have no clue whether the regime will be better or worse under him. One of the many problems that analysts have outlined is that it isn't just the outside world that is unfamiliar with Kim Jong-un. Most North Koreans, outs...	[ "Kim Jong-il's funeral took place on 28 December in Pyongyang, with a mourning period lasting until the following day. South Korea's military was immediately put on alert after the announcement and its National Security Council convened for an emergency meeting, out of concern that political jockeying in North Kore...
what the suds in dish soap do and how they work.	Dish soap is made out of special molecules are both polar (slight charge) and non-polar. This property allows them to form a microscopic "bubble" called a [micelle](_URL_0_) around non-polar molecules (such as fat and oils) which can then be dissolved in water. The reason it is so hard to get things like oil off of you...	[ "A soap dish is a shallow, open container or platform where a bar of soap may be placed to dry after use. Soap dishes are usually located in or near a sink, shower, or bathtub. Most soap dishes are made from waterproof materials such as plastic, ceramic, metal, or glass, though some are made from bamboo. A china sa...
Atlatls VS bows in the Americas	[This post](_URL_0_) has it that bows and arrows emerged between 3-4 thousand years ago, probably independently, in a number of locations in North America. To my knowledge, atlatls were widely spread throughout North America both before and after bows were in use.	[ "The spear-thrower was used by early Americans as well. It may have been introduced to America during the immigration across the Bering Land Bridge, and despite the later introduction of the bow and arrow, atlatl use was widespread at the time of first European contact. Atlatls are represented in the art of multipl...
What is the limiting factor in human eyesight?	At some point, the eye will be diffraction limited (see Rayleigh Criterion and Angular Resolution [here](_URL_0_)). Even if your eye was physically perfect/ideal in every way, your vision is still limited by the size of the circular aperture of the eye. I actually did a presentation on this for a lower division phy...	[ "In anatomy, an eyestalk (sometimes spelled as eye stalk or known as an ommatophore) is a protrusion that extends the eye away from the body, giving the eye a better field of vision. It is a common feature in nature and frequently appears in fiction.\n", "The external limiting membrane (or outer limiting membrane...
is it true that the 1960's-1970's middle east was super civilized and progressive, and if so, what the hell happened?	Pakistani here! In the 60s, we were very progressive. Free market economy, thriving banking sector, largely secularist (Alcohol, clubbing and everything was part of society). Then the cold war happened. In the mid 70s Prime Minister Bhutto, a socialist, was forced to outlaw alcohol by pressure from the Islamic clergy...	[ "The modern Middle East was shaped by three things: departure of European powers, the founding of Israel, and the growing importance of the oil industry. These developments led increased U.S. involvement in Middle East. The United States was the ultimate guarantor of the region's stability as well as the dominant f...
What are some good books about US Armored Forces in WWII	More generally Band of Brothers and Citizen Soldier are two great books if you want more of a narrative than a by-the-numbers historical account. Do realize that with books by Steven Ambrose you would do well to research what may or may not have been plagiarized. The core message is still solid even if Ambrose had stic...	[ "At the end of World War II, two 6th Armored Division G3 officers, Majors Paul L. Bogen and Clyde J. Burke along with Aide-de-Camp Captain Cyrus R. Shockey, compiled a \"Combat Record of the Sixth Armored Division in the European Theatre of Operations 18 July 1944-8 May 1945\". The official history by George F. Hof...
I'm interested in the history of the addition of Hawaii to the United States. What was the reasoning behind it? Did the people accept it with open arms?	Hawaii was a major importer of sugar to the United States in the mid and late 19th century. However, after the McKinley Tariff (1890), which raised taxes on imports significantly, the sugar growers realized that they could bypass the costly tariff by becoming annexed into the US. They staged a rebellion against the loc...	[ "Upon the inauguration of William McKinley as the 25th President of the United States on March 4, 1897, the Republic of Hawaii resumed negotiations for annexation, which continued into the summer of 1898. In April 1898, the United States went to war with Spain, and Republic of Hawaii declared its neutrality. In pra...
why do (most) countries have a tomb of the unknown soldier?	It's mainly just a respect thing. War leaves a lot of dead bodies that no one can identify. I think the British or the French started the tradition around WW1.	[ "Many countries have buried an unidentified soldier (or other member of the military) in a prominent location as a form of respect for all unidentified war dead. The United Kingdom's Tomb of the Unknown Warrior is in Westminster Abbey, France's is buried underneath the Arc de Triomphe, Italy's is buried in the Monu...
the perceived animosity of the nypd towards bill de blasio.	The mayor has repeatedly come across as being in support of those who are angry with the police, even in instances where that anger is not justified. The mayor isn't seen as being on the side of his police force.	[ "Under Mayor Bloomberg, Kelly's NYPD also incurred criticism for its handling of the protests surrounding the 2004 Republican National Convention, which resulted in the City of New York having to pay out millions in settlement of lawsuits for false arrest and civil rights violations, as well as for its rough treatm...
Where does the energy go when particle-antiparticle pairs spontaneously appear and annihilate?	The energy doesn't go anywhere, because there was zero energy to begin with and zero energy after. The particle-antiparticle pairs you're referring to are called virtual particles. They aren't real particles, and they don't actually exist. They're mathematical tools that are used in calculations, but they fail to ha...	[ "If a particle and antiparticle are in the appropriate quantum states, then they can annihilate each other and produce other particles. Reactions such as + → + (the two-photon annihilation of an electron-positron pair) are an example. The single-photon annihilation of an electron-positron pair, + → , cannot ...

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