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5pagl7
|
what happens if a president is elected and they do not have a so to take the first lady/gentleman position?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5pagl7/eli5_what_happens_if_a_president_is_elected_and/
|
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"There's only one or two cases of a president not having an SO. It's a campaigning thing. People will vote for the family man over the lecherous man. Presidents are also usually quite old.",
"In Thomas Jefferson's case, for example, Dolly Madison (his SecState's wife) did First Lady stuff. A bachelor or female President would probably find a relative or close friend to do the job.",
"Well, in the case of President James Buchanan (who was a bachelor), he had his niece be the official White House hostess, therefore making her acting First Lady. ",
"Nothing has to \"happen.\" First Lady is not a position. He would just be a single President.",
"First Lady is just a female relative. James Buchanan had his niece, and I think there were a few more people who didn't have their wives act as first lady."
]
}
|
[] |
[] |
[
[],
[],
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||
13facs
|
how do google's driverless cars work?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/13facs/eli5_how_do_googles_driverless_cars_work/
|
{
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"A system including cameras, GPS, proximity sensors all work together to drive the car. Pretty much every road in north america is mapped on GPS. The GPS gives the rough information on the route the car should take and what to expect in terms of directions. That information is few to the computer on board that tracks the cars position. The cameras and proximity sensors work to control the more important functions. The cameras are used to pick up markers on the road, like lines, helping position the car in the lane. The cameras are also helpful for detecting things like stop lights and signs, using an advance for of recognition software. Proximity sensors work to track the position of the surrounding cars, they track the speed and distance of the other vehicles, helping the car avoid accidents.\n\nAll the information is processed by a computer onboard and using pre-written algorithms, the computer drives itself. "
]
}
|
[] |
[] |
[
[]
] |
||
4yjn38
|
how does up voting photos in reddit effect their visibility in google searches?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4yjn38/eli5_how_does_up_voting_photos_in_reddit_effect/
|
{
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"text": [
"I believe that every time you upvote an image a link to it is created in your users folder. For example you can see all of my upvotes here:\n_URL_0_\n\nEach upvote generates a new link. When a lot of users upvote an image it creates a lot of backlinks.\n\nGoogle uses the amount of backlinks as one of the determining factors for what is the most \"relevant\" item. It also uses the anchor text (link text) to determine which keywords it will appear for. Thus you will usually see the keyword in the title.\n\nThe real algorithm that google uses is far more complicated then that. But people have figured out that by upvoting you can create enough value to push an image to the front page. "
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/user/barbodelli/upvoted/"
]
] |
||
2xo7aq
|
What nationalities were the Shock Troops of the British Empire during World War I?
|
From what I've read of the Canadian Expeditionary Force, I know that the British military used the Canadian Corps for Shock Troops.
Were there any other Shock Troops that the British used, and if there were, what nationality were they? If none of them were actually British, why did the British military almost exclusively use colonial forces for Shock Troops?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2xo7aq/what_nationalities_were_the_shock_troops_of_the/
|
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"\"Shock Troops\" was a term liberally used in the First World War. Most notably, the Stosstruppen or Shock troops that the Germans experimented with in 1916, and finally began forming battalions and regiments by 1917, and whole divisions in 1918. What they involve were removing the best, most experienced, most enterprising soldiers from regular infantry units, and assigning them the role of infiltrating enemy positions, reducing resistance or continuing onwards, leaving pockets for the infantry to mop up. While they proved effective, they took horrible casualties in 1918, irreplaceable at the time, and left the regular forces without man experienced core.\n\nContrast this with the British, who from 1916 onwards (post-Somme) radically re-thought their infantry tactics and doctrine, and already had a rotation system that allowed for these reforms to be distilled to every division, brigade and battalion in the BEF. The difference with the ANZAC and Canadian corps was that these were actual Corps, c. 4 divisions that from 1916 onwards always served in their native corps, whereas British division regularly shifted around. This meant that they operated much more closely, and were somewhat more cohesive. \n\nThey were certainly excellent, certainly 'shock troops', but British divisions fought just as well, and just as hard. Unlike the German system, the BEF emphasized training and cohesion of all units, combined arms really, and this was a key to victory in 1918.",
"In addition to the answer given by /u/DuxBelisarius I'll give you a quote from an essay by John Terraine on the Battle of Amiens:\n\n > It was a well-established fact that when either the Australians or the Canadians appeared in a sector trouble was brewing. This was particularly true of the Canadians because of their Government’s rigid insistence that their divisions should never be separated. It was, therefore, necessary not only to hide completely the presence of this Corps, 100,000 strong, which would have to be in the front-line at zero hour, but also to hide the fact that it was no longer in the sector, far to the North, where the Germans would already have identified it. \n\nThe Canadian Corps was the largest single cohesive fighting unit in the entire BEF - what's more it was experienced *as a unit*. Most other Corps were fairly amorphous. Brigades and battalions would come and go, but the Canadian Corps was maintained intact from Vimy through to the end. This engendered a better degree of trust and cooperation between staff and fighting officers, and between the officers of the different subordinate formations, and thus ensued improved efficiency and efficacy overall.\n\nWhat's more the Canadian Corps was unusually large (at around 100,000 men, it could field more fighting troops than today's British *and* Canadian armies combined). This was because the Canadians were able to resist the cutting down of Brigades from 4 to 3 Battalions, and maintaining 4 active Divisions in the Corps instead of 3. \n\nSo yes, its no exaggeration to say they were viewed and used as 'Shock Troops' in WWI due to the Canadian Corps' superior organisation and structure.\n\n*HOWEVER* - it was not only Canadian or ANZAC outfits that were capable of great feats of arms. Arguably the most astonishing successes of the entire war was the breaching of the Hindenburg line by the St Quentin canal by the 46th (Territorial) Division - a thoroughly ordinary British infantry Division that had up to that time completely distinguished itself only by its bloody failure to take the Hohenzollern Redoubt after Loos in 1915. \n\nThis emphasizes and important point: That the success of the BEF in 1918 was not down to a few elite units, but to the overall proficiency and fighting skill of the army in its entirety. \n"
]
}
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[] |
[] |
[
[],
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4evn5p
|
How do rocket engines prevent back-flow of ignited fuel?
|
In other words, how is ignited fuel stopped from flowing up the fuel lines? And also if it did, what would happen?
(Regard bi propellant rockets.)
|
askscience
|
https://www.reddit.com/r/askscience/comments/4evn5p/how_do_rocket_engines_prevent_backflow_of_ignited/
|
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"The fuel *can't* burn in the fuel line.... there is no oxidizer in the fuel line.\n\nAs for why a fuel/oxidizer mix can't get back into one of the lines... too much pressure going the other way. Here's a description of rocket fuel injection from [wikipedia's article on liquid propellant rockets](_URL_0_):\n\n > Injectors today classically consist of a number of small holes which aim jets of fuel and oxidiser so that they collide at a point in space a short distance away from the injector plate. This helps to break the flow up into small droplets that burn more easily.",
"They typically use a turbopump. The turbopump allows for the pressure before the fuel injector to be higher than the pressure in the combustion chamber, ensuring that the mixture does not go back into the fuel injector.",
"It sounds like you are asking about liquid fueled rocket motors. The fuel and oxydizer are stored in separate tanks and injected into the combustion chamber by pumps. There is no place for a flame front to go other than the combusion chamber. "
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Liquid-propellant_rocket#Injectors"
],
[],
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|
ws3dp
|
Are hitler and Stalin diagnosed as crazy today?
|
Hey /r/askhistorians ! Here again for another question.
So as a fellow student studying Hitler's rise to power, and his relations with Stalin, I'd like to ask a simple question.
Basically,my teacher seemed to often attribute specific choices of these two leaders to the "he was crazy" excuse. Don't get me wrong, I do agree wanting to exterminate all the Jews or the purges were terrible events, I'm not trying to defend the two. Simply that I remember asking "why the jews?" and instead of giving me a viable answer like "a large portion of the German bourgeois were Jewish" my teacher would just say "he was crazy and truly believed they were evil".
So, I'm curious to see wether we have any source possibly written by hitler or Stalin, explaining the reasons for some of their actions, or if they were genuinely crazy.
For example, the purges, did Stalin have a strategic use to kill off thousands of civilians, or was he simply paranoid and wanted to kill off anyone against him?
For the jewish, do we have proof that they were indeed the majority of the rich Germans, or did hitler truly believe they were the sources of evil?
Is there any actions undertaken that have harmed the country a whole lot, with no viable explaination for the action to be taken, possibly leading to the conclusion that either of them were indeed crazy, or did they have a reason that simply required a lot to be killed off?
Hope this question doesn't come up too often/ wasn't too hard to understand!
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/ws3dp/are_hitler_and_stalin_diagnosed_as_crazy_today/
|
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"text": [
"Hey, cool question. I really like that you asked \"*Are Hitler and Stalin diagnosed as crazy* ***today***\" not \"Where they crazy?\".\n\nHitler is often diagnosed as crazy nowadays. Shit-/incest fetish, paranoia, being depressive - all those traits are often attributed to him. In my eyes that's **wrong on many, many levels**.\n\nPeople do this in an attempt to vilify him even more, which is retarded. The dude is literally Hitler. Maybe it's also done in an attempt to trivialize him and his actions. Sometimes people also try to put irony where it doesn't belong (See all \"Hitler was jewish\"-BS). He simply wasn't. His positions were shared by many and still are, today. Not even his antisemitism and racism were pathological, in the end politics (Japanese were somehow kinda Aryan, not all Semites were Semites, etc) and personal feelings (Bloch, a jewish doctor he protected) were more important.\n\nGermany made money with the Holocaust and many (even internationally) did think that the world would be a better place without jews. The political and moral climate *today* make it seem crazy, but until the late 60's most people didn't give a shit about the Holocaust. Even in anti-fascist nations, like the GDR, it was very rarely talked about. Anti-Semitism back than was rampant, in Russia, France, Romania and Poland even more than in Germany.\n\nStalin: The purges killed many innocents but also any opposition to the revolution or Stalin himself. That was the main reason he was able to keep in power the first months of the Blitzkrieg, while Russia was nearly annihilated. There was no one to succeed him. All other important revolutionists, all czarists, the political, democratic bourgeoisie and the former heads of the armed forced where imprisoned or dead. \n\nCalling those two guys crazy is lazy, simple history and disrespectful to the people who lived back than. There were very good reasons to be pro-Hitler or Stalin in 1933 and their agenda didn't come out of the blue.",
"There is a hidden agenda in trying to label Hitler as mad: it is an attempt to shift away responsibility. By labelling Hitler as mad, it takes away any responsibility Europe had in Auschwitz. It's easy to claim that Europeans were \"led astray\" by Hitler, or \"had the misfortune\" of falling under his spell.\n\nThere are many crazy people in the world, but most do not manage to engulf the world in world war, or conduct homicide in an industrial scale.\n\nHitler didn't have to be crazy for the horrors of WWII to occur. Firstly, there was a power imbalance in Europe at the time of his rise. European powers had divided up the world into empires, *but Germany arrived late to the party, unifying only in the 1870s.* There could not be a stable Europe as long as a power like Germany remained excluded from the predatory practices of other powers. This had led to WWI, and was still unresolved by the outbreak of WWII.\n\nSecondly, hatred of Jews was not exclusive to Hitler. In the 30s, Jews were not only seen as traitors who had sold out Germany to the allied powers of WWI, but they were also seen (paradoxically) as simultaneously *Bolsheviks* (Marx, Trotsky, Luxemburg had been Jewish), and also *predatory financial capitalists* (like the Rothschilds). During Germany's crisis of capitalism in the 20s, the twin problems of communism and predatory capitalism *was blamed on Jews*. There was no need for a madman to convince people of this (though Hitler was able to exploit this fear very successfully). Antisemitism in this era is a result of a phobia of communism, and a result of finance capital.\n\nCalling Hitler a madman is doing serious analysis a disservice. Whether he was or not is immaterial. What matters is that *Europeans did not need to be led by a madman to build Auschwitz*.",
" > With satanic joy in his face, the black-haired Jewish youth lurks in wait for the unsuspecting girl whom he defiles with his blood, thus stealing her from her people. With every means he tries to destroy the racial foundations of the people he has set out to subjugate. Just as he himself systematically ruins women and girls, he does not shrink back from pulling down the blood barriers for others, even on a large scale. It was and it is Jews who bring the Negroes into the Rhineland, always with the same secret thought and clear aim of ruining the hated white race by the necessarily resulting bastardization, throwing it down from its cultural and political height, and himself rising to be its master.\n\nIf we are to take Hitler at his word it would seem he did genuinely believe the jews to be evil",
"It's hard to diagnose someone as \"crazy\". There is a wide range of personality disorders, with different symptoms and behaviour. It is impossible to diagnose someone correctly without meeting him, talking to him for quite a long time and there is still a great chance of error. If you want a modern example, look at the trial of Anders Breivik, the norwegian right wing terrorist. There is a debate if he is crazy, different doctors come to different conclusions and they had the chance to examine him. You can't do this with a dead person you don't know many personal things about.\n\nThere are some people who tried this and they come to different conclusions. There is no english wikipedia article about this, but you might try Google Translate:\n_URL_0_"
]
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[],
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"http://de.wikipedia.org/wiki/Psychopathographie_Adolf_Hitlers"
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|
1qitg6
|
the religion of jehova's witness
|
I'm surprised this isn't on here already. I would love to know all the basic fundamental beliefs or just what they would tell me if they came to my door.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1qitg6/eli5_the_religion_of_jehovas_witness/
|
{
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"text": [
"Using reddit search I found:\n\nELI5: Jehovah's Witnesses\n\n_URL_0_"
]
}
|
[] |
[] |
[
[
"http://www.reddit.com/r/explainlikeimfive/comments/lee73/eli5_jehovahs_witnesses/"
]
] |
|
6298az
|
why aren't people in congress who took money from people not forced to abstain from a vote?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6298az/eli5_why_arent_people_in_congress_who_took_money/
|
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"text": [
"Because then all I'd have to do to stop something from passing is donate small amounts of money to some people who supported a bill. ",
"It is because the purpose of the legislature is to influenced by people.\n\nYour representatives are supposed to represent you. The best way to insure they do just that is to help elect the one that wants what you want. So you donate money to that person to help them get elected and to help them get re-elected. In turn they vote how you want them to. To know how you want them to vote you call them, send them mail, or have a meeting with them.\n\nTo be clear it is illegal for Congress or Senate members to receive money or gifts in exchange for voting a certain way. And that is not is what is meant when news or media say \"congress took money\". What that means is that those members have received campaign donations from someone."
]
}
|
[] |
[] |
[
[],
[]
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||
155l3i
|
when you flip your rear-view mirror down in the night time, why do the headlights behind you seem less bright?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/155l3i/eli5_when_you_flip_your_rearview_mirror_down_in/
|
{
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"text": [
"It's a second mirror that has a less reflective surface. If you take a flashlight to the mirrors at night, you can see where they each reflect to.",
"The mirror isn't flat; the glass is thicker at the top forming a wedge shape. The back of the glass is silvered to make it very reflective. When you tilt the mirror tab, the silvered portion points away from you, so you don't get a great reflection. The dim reflection you end up seeing is a reflection off the glass itself, similar to the reflection you'd see when looking out of a window at night.\n\nNewer or more high-end cars use a different method of dimming. There are sensors which determine if the level of light is too much. This then sends a signal to the glass itself to alter is light transmitting properties. This is a property known as electrochromism. "
]
}
|
[] |
[] |
[
[],
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||
sx5r4
|
compression of video, photo and audio.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/sx5r4/eli5_compression_of_video_photo_and_audio/
|
{
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"text": [
"Photo: Instead of recording the exact color of every pixel, either reduce the number of colors used (gif), or make a note that the next however number of pixels are the same color, followed by a bunch of pixels that are a different color, and so on.\n\nAudio: instead of recording every single tone of a song, only keep the loudest parts. Maybe the singer is singing while there is a loud cymbal crash. You can't really hear the singer, so cut that part out and leave the loud cymbal. If you don't know the song well, you won't usually be able to tell, unless the compression is really high.\n\nVideo: instead of keeping all of the info of every image in the video, analyze the pictures and record only how the images change from frame to frame. The background doesn't change much? Then only change the parts of the picture where someone is moving! You can see the edges of the moving stuff in badly or highly compressed movies."
]
}
|
[] |
[] |
[
[]
] |
||
9ptw3s
|
what does falconry actually involve?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9ptw3s/eli5_what_does_falconry_actually_involve/
|
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"text": [
"Im a falconer. There's kind of a difference between how we take the sport on and how they do it in the arab world. In north america we use trained raptors to hunt \"fur or feather\" meaning either small furry animals or gamebirds and water fowl. Our method is almost just like regular hunting but with birds of prey instead of firearms. In the middle east the sport is more like a fox hunt that uses high octane gyr falcons or gyr hybrids and a bustard called the houbara.\n\nIn either case the bird is conditioned using some degree of weight management and various different training methods. It involves finding a weight at which a bird is both responsive and healthy then maintaining it by weighing them and their food on a daily basis. "
]
}
|
[] |
[] |
[
[]
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||
e4dtua
|
How does a history post-grad student go about finding their thesis topic?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/e4dtua/how_does_a_history_postgrad_student_go_about/
|
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"text": [
"It's really a case of thinking about what you find interesting, and what will hold your attention for however long you have to write the piece of work. I personally think that's the most important thing. There will be ups and downs in this time, and it will be much easier to get through it if you care about the work. \n\nOtherwise, the guidance is pretty standard:\n\n- It needs to be possible. Do you have the sources? Can you access the sources? Do you have the skills to use those sources? Do you have the money and time? \n- Has this topic been done before? It is not necessary or always even possible to have a totally unique piece of work; it will do and is expected to build on the work of others. If very very little has been done on it -- is there a reason such as a lack of sources? If there has been very much done on it, what are the chances that you can find a way to approach it from a different angle? It has to have at least the potential of originality to begin with. \n- What have you done so far? Are there some gaps in literature that you would like to fill? Or do you think the things you've done so far have been boring and you have no interest in them? What are the themes that you enjoy the most? Perhaps you are keen on radical or women's history? Eighteenth century history? History of medicine? Are there new waves of historiography that you'd like to join? Do you like working with newspapers?\n- Take your time. Your first idea may not be the best one, and even if you settle on a good one it's often the case that proposals look very little like the finished pieces of work. \n- Take advice from your tutors etc. Do they see potential in certain topics? Similarly, who will be your supervisor? Did you choose them because you like them as a person or because you want to do the topic they have expertise in? It needs to be a little bit of both. Don't settle on Russian history just because your Russian history tutor at undergrad was friendly (and you don't speak Russian!). \n- Be inspired. All my theses so far have come from reading other people's works and \"stealing\" ideas, which is probably the most common approach I've noticed. Sometimes I took their sources and ran with them to write about something else. Other times I took a person's theory and applied it to the sources I want to work with. \n\n\nGood luck. I'm sure you will receive some good advice here.",
"My advice is to pick a topic strategically, the kind of thing you know markers will like. My thesis was on price discovery mechanics in the pre-war Tokyo stock exchange, which won me a prize for best thesis, not because it was extremely well-written (my friends are significantly better writers and researchers than I am), but because it ticked a lot of boxes which made it seem impressive.\n\n1. Language: Theses which use sources in a foreign language are always impressive, be sure to include extracts of the source in your Appendix to show off.\n\n2. Statistics: One of the biggest criticisms of history is that it's often wishy-washy and has no genuine grounding. This can be solved with the power of statistics, and I mean genuine statistical analysis with the appropriate tests and robustness checks and everything. Most historians don't actually understand statistical analysis, but they all really see the point of it and will be impressed by what they think is super complex but is actually relatively simple.\n\n3. New Work: The best way to make your thesis stand out is to point to a bunch of other theses and say \"to my knowledge there are no theses which do xxx\" and then have some commentary on the shortcomings of not doing that.\n\n4. Inter-disciplinary: This works very well if you have strong understanding of something very technical (e.g. engineering, finance, physics). You can then conduct very basic technical analysis, which will sound very impressive to a pure historian.\n\n5. Algebra: One of the most basic types of mathematics, but historians will rarely come across it and will be shocked. This is distinct from the statistical analysis, you want to use this to express concepts. For example, a normal thesis will talk about the various advantages of the Mongol compound bow and maybe some case studies. Imagine how your marker would react to an equation for the force generation to draw weight ratio, with genuine understanding and analysis of the implications of course.\n\n6. Data: Most historians will use case studies. Sometimes the entire thesis will just be about one case. This is fine and is an accepted way of doing things, but is extremely prone to omissions and biases. An impressive data source will be large (\"we compiled 224,000 maintenance reports for tanks used on the Western Front\"), exhaustive (\"these represent all reports submitted during the war\"), and embrace rather than skirt around biases (\"the data is likely biased due to the most damaged tanks being scrapped rather than repaired\")\n\nDo all these and you will probably have a very impressive thesis.",
"There are probably as many answers as there are students! I know people who knew what they wanted to write about even when they were undergrads, so they applied to a specific school with a specific advisor who could help them with that subject. \n\nIt may also depend on the school/program you're in. They might have rules about finding a topic and an advisor before you apply, or you might be able to figure things out along the way, like I did. For me, I had a general idea of the time period I wanted to study, but I didn't narrow down a topic until I was already in the PhD program. I took a class about medieval violence and vengeance, and my essay for that class turned into the nucleus of my thesis (and then turned back into a smaller article, which was my first publication). I've been asked about this in job interviews...how did I come to this field? Well it just sort of happened accidentally! Why do I study this? Because it's neat! Those explanations have never gotten me a job but I stick by them!\n\nSo there isn't necessarily one right way to do it, and sometimes it happens in unexpected ways.",
"The above posts are all terrific. I would also add this: be flexible. I had an idea of what I wanted to do, but then I was denied access to Egypt (I work on 19th century Egyptian history) and I had to do my research in Europe. The actual topic of the thesis was based on a discovery in the archives—an archive I hadn’t expected to be working in, and it went from there. I managed to write a thesis on 19th and early 20th century Egypt without actually doing any research there (god bless the Internet and friends at Egyptian universities!)\n\nIn my experience, most researchers change or drastically revise their topics based on what evidence they actually find—the only ones who haven’t had already done quite a bit of work and knew what they were likely to encounter—and many are quite panicked about it (“but I said I was going to do x!”). It’s all part of the process!"
]
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[] |
[] |
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[],
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54fl8c
|
How did vegetarian cultures start?
|
In India, there's a large proportion of vegetarians, and I believe this is often attached to religion. How did this start? E.g. was it more ethics towards animals, or fear of tainted meat, or religious purity, or something else?
That's the only example I know of, but if there are/were other similar cultures, I'd love to hear how they started – I'm interested in the general question, not India specifically.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/54fl8c/how_did_vegetarian_cultures_start/
|
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"In ancient India, the brahmin (\"priest\") caste engaged in vegetarianism out of religious belief. The killing of animals was associated with bad karma, so brahmins maintained their diets as a sign of karmic purity. It's also important to note that the lush Indian subcontinent was uniquely suited to sustaining a vegetarian lifestyle, due to its wide biodiversity. A vegetarian diet would not be possible in Alaska, for example.\n\nReligious vegetarianism began to wane as Buddhism spread. Contrary to popular belief, the Buddha allowed his followers to eat meat, so long as the animal was not killed specifically for the follower in question. The Buddha wanted his teachings to be available to all castes, not just brahmins. This allowed Buddhism to spread to arid Tibet and China even as it died out in its country of origin, India. Even the Dalai Lama is not a vegetarian!\n\nI am not aware of vegetarianism existing in any large scale prior to Upanishadic India, but I may be wrong.\n\nSources:\n\nThe Bloodless Revolution: Radical Vegetarians and the Discovery of India by Tristam Stuart\n\nIn This Very Life by Sayadaw U Pandita (RIP)\n\nThe Upanishads, Penguin Classics, translated by Juan Mascaro"
]
}
|
[] |
[] |
[
[]
] |
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28l5l1
|
Can I make something float?
|
I am not really good on this physics thing but I'll try to sum it up.
I think gravity has a 9.8 N strenght right? If I could feel something with, per exemple, a balloon with Helium untill it equals gravity will my balloon float on the middle of the air?
|
askscience
|
http://www.reddit.com/r/askscience/comments/28l5l1/can_i_make_something_float/
|
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"First of all, just to clarify, gravity doesn't have a uniform strength of 9.8 Newtons. The acceleration due to gravity is 9.8 m/s^2, and because F=ma (for applications near the surface of the earth), the force of gravity on earth equals mg (or 9.8m).\n\nNow to answer your question, yes, objects can float if the summation of forces on them is zero. To simplify, if a 2kg object has a gravitational, downward force of 19.6 N, you will need an upward force of 19.6 N in order to make it 'float'. Balloons usually move upwards because helium provides a buoyant force greater than the force of gravity on the balloon, causing the net force on the balloon to point up. \n\nIn your example, yes, if you filled a balloon so that it had a buoyant force EXACTLY equal to the force of gravity acting on it, it would float perfectly still in mid-air.",
"Newtons are a unit of force. An object with a mass of 1 kg will be pulled down with a force of 9.8 N, and \n\nIf downwards gravity and upwards buoyant force balance, we say the object is neutrally buoyant. Your balloon needs to have the same density as the air it displaces to do this. Submarines and balloons that are precisely neutrally buoyant tend to stay where you left them.\n\n[Hovering egg lab demonstration](_URL_0_)",
"Another easy test for this is to fill a balloon with He and keep it around the house for a week. As the He leaks out of the balloon it will slowly sink. During that time you will reach an equilibrium where the balloon will float without rising or falling. "
]
}
|
[] |
[] |
[
[],
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"https://www.youtube.com/watch?feature=player_detailpage&v=JDJ-Xy9MgZk#t=51"
],
[]
] |
|
2uvye3
|
Economic Inequality between Northern and Southern Europe
|
I tried to look through the FAQ and recent posts, but could find anything on the subject.
What has caused the economic inequality between Northern Europe (UK, France, Germany) and Southern Europe (Spain, Greece, Italy etc)?
Has this economic disparity existed for a long time?
I am wondering about the historical background of the recent Eurozone crisis. I understand that you cannot cover things later than 1995.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2uvye3/economic_inequality_between_northern_and_southern/
|
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"It actually has a lot to do with history.\n\nThe most important thing to understand, I think, is the way the Industrial Revolution spread through Europe. As you may have learned, England was the starting point. What made England special? Firstly, goods and people could be moved fairly cheaply compared to the continent: there were no internal tariffs, you could ship goods up and down the coast line since England was an island. Secondly, there were plenty of natural resources, both within the UK and in the colonies. Thirdly, the rise of enclosure left a lot of peasants without land: this meant that there was a force of unemployed workers that could be exploited. This is why wages were tied to the price of bread: the idea was that if a family had to work to have enough to eat each day, there would be more motivation to work. Couple that with the fact that England has had more or less the same political regime since the Industrial Revolution (a parliamentary monarchy).\n\nFrance and Germany had a harder time of it, but still had the advantage of colonies and raw materials. They also played off each other in various wars, which gave them motivations to industrialize. France had unified after the French Revolution and Germany had unified under Bismarck. \n\nHowever, the South of Europe (Portugal, Italy, Greece and Spain) were never fully industrialized. Even today, Italy, Greece, Spain and Portugal are primarily agricultural countries. They also did not long benefit from colonies: Italy managed to take Ethiopia in Africa, but did not hold it for long; Spain, on the other hand, decided to take on the US and lost its last important colonies. Portugal held on far longer, but did not exercise much control over its colonies and had lost its most important colony, Brazil, soon after the Industrial Revolution had begun in Northern Europe. The Greeks managed to succeed from the Ottoman Empire, but they were comparatively a very young nation that got involved in the Balkans wars with Croatia, Bosnia, Albania, Macedonia, Serbia, Bulgaria, Romanians, Turks, Slovenes, and Montenegrins. They were pretty much crushed. Then they were invaded by fascist Italy during WWII; even though they managed to fend off the Italians, Nazi Germany came in to bail their ally out and both the Allies and the Axis bombed Greece at some point. \n\nThe other problem is that these countries do not have very many resources for industrialization. Portugal in particular is dependent on other countries for wheat. Portugal, Spain, and Italy have all had totalitarian, fascist dictators (Salazar, Franco, and Mussolini). Italy's fascist regime ended after WWII, but Salazar's and Franco's regimes continued into the mid to late 20th century. Italy has also been plagued by corruption since WWII. \n\nAll this means that Portugal, Italy, Spain, and Greece were not really able to industrialize until much later than the UK, France and Germany. When the European Union was formed, these countries took advantage of other EU members' money to try and modernize their economy. The problem is that after several years, the recession came along and they're not returning well on their investments. This means that they default on these old loans, they take austerity measures, and austerity measures in turn make people unhappy; hence, they are less likely to consume certain products, which makes the economy even worse. \n\n"
]
}
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[] |
[] |
[
[]
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dtdou1
|
Given Elon Musk's recent comments about finally being able to reuse rockets: Why is it so difficult to recover and reuse them?
|
askscience
|
https://www.reddit.com/r/askscience/comments/dtdou1/given_elon_musks_recent_comments_about_finally/
|
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"There are lots of ways to do some kind of rocket recovery and thus many reasons not to. I can only talk about a few. \n\nRecovery is the first problem. \n\nBoosters which detach early land in the ocean which can corrode the components to such a degree that it is not worth repairing them. You also have to slow them down so that they are not destroyed on impact. This can be done with parachutes but Musk has stated that they would need to adjust the structural design of their rockets to be able to handle the force of a parachute and they didn’t want to do that. Components jettisoned at higher speeds and altitudes may not survive the heat of reentry and could burn up in the way down. Designing them to handle this condition could be difficult or again too expensive to make it worthwhile. \n\nThe second problem is refurbishment. \n\nEven with perfect recovery, rockets suffer a lot of stress and wear when they are used and if you are going to put $100,000,000 of payload on that old rocket you better be sure that it will work perfectly despite the wear it sustained last time. This basically means that you take it all apart and rebuild it. This can be more expensive than building a new engine.",
"Initial interest in rockets was mainly for military applications. You fire all your rockets towards the opponent, and the war is over. Reuse makes no sense. The Space Shuttle tried reusability but had various issues that made it more expensive than expendable rockets, that reduced interest in reusable rockets. SpaceX worked on it again, and they made it work - only for the first stage for now, but that helps already.\n\nRockets go very fast. On ascent, the nose gets nearly all the atmospheric forces, the boosters can fly without having to worry about it. To recover a booster it has to fly through the atmosphere, at a typical speed of 2 km/s. It has to survive that and slow down enough to land safely. Landing such a big fast object is difficult. Reusing an upper stage means recovering it from orbit at ~7 km/s, or at least a much faster speed (if the rocket has more than two stages), that makes it even harder.\n\nYou need to add parachutes or keep fuel for a landing burn, you need to keep fuel for steering to your landing site before. You need something to steer in the atmosphere and you might need landing legs. All these things have mass and reduce the payload of the rocket.\n\nRecovery and refurbishment must be cheaper than a new booster. That means most of your components now have to survive many launches instead of just one. Rocket engines in particular operate close to the limits of their technology. Their design lifetime is often just a bit longer than the time they are used in flight. Making an engine that can fly 3, 10, or even 100-1000 times (while still being efficient and having a lot of thrust) is very difficult. There are also some extra cost for landing pads/ships and so on.",
"The short answer, which hasn't really been touched on yet, is that the percent of a rockets total mass that you can actually put in orbit is is tiny. You're typically about 96% rocket (fuel tanks, fuel, avionics, etc), and 4% payload (what gets to stay in space). This makes adding absolutely anything to your rocket incredibly expensive. You increase the weight of your rocket just 2% by adding a landing system? boom your payload capacity to orbit just got cut in half.\n\nThe other half of the problem, which has been touched on, is that it's very, very hard. 2-7Km/s velocity to 0 is hard. Getting rid of that energy in just a few minutes, and not in a way that ends with a boom, is hard. And there's this massive downside that it's difficult if not impossible to really test your hardware without, you know, launching a rocket. And that's expensive on the order of \\~100+ million. Sweet engineering solutions aren't the product of crazy smart people sitting at a desk for a few years, designing a thing that's never been done before, and having it work right on the 1st, 2nd, or even 10th try. Testing things in the real word is a shortcut to the truth. These solutions are the product of extreme trial and error, backed and refined with analysis, and the willingness to create a mess along the way. When trial and error is ridiculously expensive, things progress slowly. And when failure isn't an option, things stop progressing at all."
]
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||
5cctg1
|
what has changed culturally/politically that people believed it when they were warned about the hole in the ozone, but not about climate change now?
|
I am too young to have really understood the turn around with the ozone, but it seems like it would be as abstract to the layman as climate science is now. But yet, the whole world seems to have gotten on board with getting rid of CFCs and reversing the trend. Why is this not happening with climate change awareness?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5cctg1/eli5_what_has_changed_culturallypolitically_that/
|
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"There's a belief that the Earth can balance itself to sustain environment. I've heard it hundreds of times, this idea is popular between climate change deniers and religious people. But it has nothing to do with reality. If you want to know if it's possible for planet to became inhospitable, take a look on the Venus.",
"The CFC lobby was not nearly as powerful as the CO2-releasing lobby and was unable to produce enough anti-science propaganda.",
"The ozone layer was a fairly visible problem (look at this giant hole that wasn't there) with short term scary consequences (skin cancer for everyone!) which required very little personal or public financial sacrifice to fix (oh... we switch hair sprays.... that's not so bad). Amd since most of that could be fixed with relatively cheap legislation, you really didn't even need to mos people to buy in to fix the problem.\n\nCompare that to climate change which has long term consequences broad consequences diffused away from most key countries (displacenent of populations, issues in 50-100 years, etc) stemming from seemingly minor, nonthreatening visuals (would 1 or 2 degrees be that bad) and which addressing means fundamental changes in just about all aspects of our day to day life and commercial system.\n\nClinate change is therefore easier to scoff at and people/countries have far greater motivation to do it it.",
"It wasn't long ago that generally people (especially common folks) looked up to science. When scientists agreed on something, people deferred to that.\n\nThen came the evangelical movement with its literal interpretation of the Bible. If the earth is only 6000 years old (about the age you get to if you count the generations Genesis), then evolution over millions of years couldn't have happened. So scientists must be against God, and what they say must rejected.\n\nCombine that with a campaign by the big industrials whose profits were threatened by climate change talks, and you have the bulk of your answer.\n\nEdit: typo",
"I flew with the Naval Research Lab over Antarctica in the mid eighties. We carried scientist studying the ozone hole. It was easily observable and quantified in real time unlike global warning that requires some speculation about the environment in the past. By the way, two of the scientist told me the ozone hole was mainly caused by an active volcano on the continent. ",
"In the United States, about half the population denies global warming is real. For virtually everyone in America, directly or indirectly benefits from the activities that contribute to global warming. So virtually everyone is faced with two -- as Al Gore would put it -- inconvenient truths. \n\n1) Fossil fuels, non-sustainable farming, and other greenhouse-gas-emitting activities benefit you immensely.\n2) Fossil fuels are destroying the planet we all live on. \n\nThese two truths are hard to reconcile, so some people reconcile them by denying that they are both true. It's actually a relatively normal psychological defense mechanism that a lot of people use, though not always on this scale. \n\nWith the ozone hole, that's got a much smaller cause. It's CFCs, or freon. Ban CFCs and get the coolant in your AC and fridge replaced and problem solved. You don't depend as heavily on the use of freon for your livelihood, so you don't need to resort to denying the existence of the ozone hole to avoid hard truths. ",
"I could be horribly wrong about this but I want to chime in to get some further insight, but I was told that the climate is cyclical and that if you look back through almanacs and other published information regarding temperature and climate, the climate we have now, could've also been the same hundreds of years ago as far as people saying \"global warming is making each summer hotter and hotter\" but you can look back and see summers that were very similar in average temperature or even hotter. "
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ak2q53
|
German Grenades
|
What was the designer logic behind the German tomahawk grenades? These would be the grandes most commonly seen in WW2 with the wooden handles. Were they supposedly easier to throw or was there some other purpose in their design? I feel like they would have been cumbersome and heavier to carry around.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/ak2q53/german_grenades/
|
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"It's worth noting both sides experimented with a variety of grenade styles and types. You can see some [German](_URL_7_) and [French](_URL_2_) examples. The German \"discus\" design and the French \"hairbrush\" design nare especially interesting.\n\nAlthough ball-type grenades like the Mills Bomb couldn't be thrown as far as a German stick grenade, they were generally heavier - more explosive and more fragmentation from their thicker metal bodies.\n\nStick grenades weren't really especially hard to carry. The *stielhandgranate* had a clip on the head that could be easily clipped a beltloop as this [staged photo of a German soldier demonstrates](_URL_0_). This method of carriage was popular with trench raiders like [these men](_URL_6_), since it didn't interfere with movement and left the grenades close to hand.\n\nTroops also carried the grenades in large bags under each arm, as you can see in [this photo](_URL_5_). This was especially popular with stormtroopers and dedicated parties of grenadiers assigned to \"bomb\" their way down a trench. \n\nGerman troops sometimes used a combation of grenade bags and grenades on the beltloop [as you can see in this illustration](_URL_4_).\n\nFor comparison, British bombing parties carried the \"cricket ball\" Mills Bombs in [chest pouches like these](_URL_9_).\n\nDuring the 2nd Sino-Japanese War, Chinese troops often wore locally-made copies of German grenades in a bandoleer around their neck. [This photo](\n_URL_3_), [this photo](_URL_1_), and [this illustration](_URL_8_) all offer good examples of how this arrangement worked."
]
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[] |
[] |
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"https://imgur.com/yXXH6FQ",
"https://imgur.com/a/W6OZdOv",
"http://www.passioncompassion1418.com/decouvertes/english_grenades_fr.html",
"https://imgur.com/a/TiuM9Bi",
"https://imgur.com/ZC09FGZ",
"https://imgur.com/a/3uAc7ks",
"https://imgur.com/a/eJyPC6z",
"http://www.passioncompassion1418.com/decouvertes/english_grenades_all.html",
"https://imgur.com/a/260s0uz",
"https://imgur.com/a/XsM0wJm"
]
] |
|
emils6
|
why do phone cameras seem more zoomed out than eyes when looking at the same thing
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/emils6/eli5_why_do_phone_cameras_seem_more_zoomed_out/
|
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"Because they are taking the whole scene and representing it on a small screen. Then you look at the screen and it looks like a small duplication of the scene. Most camera lenses also capture a smaller field of view than your eyes do as well.",
"Your eye has a lens inside them to focus the light reflected off objects onto the retina of your eye (the image). The focal length of that lens, along with the distances involved give you a viewing angle. \n\nIf you have an SLR camera, it might have a fixed focal length or a zoom (variable focal length) lens. A camera lens of about 55mm has a similar viewing angle as our two eyes combined have. Any larger focal length would be classified as a telephoto lens and makes objects appear closer (zoomed in). Smaller focal lengths are classified as wide angle and make objects appear further away (zoomed out). \n\nBecause it would be cost prohibitive to have variable focal length optics in our phones, the smart decision was to utilize wide angle lenses. The camera resolutions are high enough to allow zooming in electronically instead of optically with an acceptable level of image degradation."
]
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[] |
[] |
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[],
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||
12veh7
|
why do international sporting organizations have french names?
|
I have always wondered why the international sporting organizations for soccer (FIFA), basketball (FIBA) and the Olympics have french names or use French predominately within their respective organizations. Any thoughts?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/12veh7/eli5_why_do_international_sporting_organizations/
|
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"Historical reasons. The modern Olympics began in the late 1800's, and FIFA was founded in 1904. While England and Germany were major players at the time, France had been a dominant cultural and military force in Europe for the previous few centuries, and was the default accepted language for international culture and diplomacy, similar to how English today is the international language of business and engineering. Even in English we call the position of having an internationally common language a \"lingua franca\" which is ~~French~~ Italian for \"~~French~~ Frankish Language\" reflecting just how dominant a force French was at the time.\n\nSince international sporting leagues were created to be, well, international, everyone assumed that everyone else would be able to speak French and set up the organizations with that in mind. Of course, it didn't hurt that France was a major initial backer for a number of these projects.\n\n(Edit) Romance languages all sound the same"
]
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[] |
[] |
[
[]
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|
2gcsty
|
when people gain weight rapidly, do they grow new hairs to cover all the skin, or do they have the same amount of hairs spaced farther apart?
|
For example on legs and arms... and then if the person lost the weight, would they be harrier afterwards because they still had all of the new hairs? If your body can grow new hairs because you gained weight, why can't it grow new hairs when you bald?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2gcsty/eli5_when_people_gain_weight_rapidly_do_they_grow/
|
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"No, they get stretch marks bro. Hair follicles just spread out and you don't grow new ones.",
"Is this why really fat guys often have patchy beards?",
"I lost about 90 pounds in the last year (about 185 now).\n\nI was hairy before, but you couldn't really tell on my arms for example because the hairs were actually spread out quite a bit. Now it's a lot more noticeable since the hair is denser (as in closer together) and appears darker than before. Same goes for face, legs etc.",
"I'm sure you have the same amount of hair. \n\nSource:My overweight Black Lab and her baldish spots on her fat rolls. ",
"I like to think it works like how space expands. Like how the stars just get infinitely farther apart because the space between them is growing. \n\nSource: I watch cosmos sometimes",
"As someone that lost weight rapidly, I can verify that I didn't lose hair I had when I was fat. It's denser now, because I'm smaller, but it really seems to be the same amount covering the same areas.\n\nI'd wager gaining weight is the same in reverse, excluding long term adaptation to normalize.",
"Just wondering where stretch marks come into play on this topic. I know women can gain weight rapidly during pregnancy which results in stretch marks but I've also seen them on people who are overweight. Do some people just get them and some don't?",
"I went undiagnosed for a while with hypothyroid and got heavy. The hair remains the same, it just spreads out.",
"You do not grow new hair follicles, they just spread out. It doesn't matter how quickly you gain weight. ",
"This question would make a good metaphor for the expanding universe.",
"I've always wondered about this as it relates to Bruce Banner turning into the Hulk.",
"Lost 60lbs (240 - > 180), noticeably hairier.",
"Sad that I know this: same number of follicles, further apart.",
"Same amount of hairs. Also losing weight causes hair loss, but it grows back.",
":S Some of the bears(men) I hang out with are super hairy. The image of them losing weight and becoming hairier has actually made me discover my limit of \"too hairy\".",
"Somewhat related side note: \n\nOne effect of malnutrition (esp. in anorexic patients) is lanugo, which is the growth of excess body hair (particularly very fine, \"peach fuzz\"-type hair on the face and neck). That happens when people reach dangerously low weights as a sort of failsafe for keeping them warm, because they don't have enough body fat to do so on its own. \n\nI think that the primary purpose of body hair is to provide warmth, and since gaining weight shouldn't have a negative effect on the body's ability to keep warm, I don't think there would be any benefit to growing new body hair. I'm no expert, though."
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|
hl7n7
|
How loud would a sound have to be to be heard around the world?
|
And as a follow up, besides destroying billions of eardrums, what effects would the sound have on the world?
|
askscience
|
http://www.reddit.com/r/askscience/comments/hl7n7/how_loud_would_a_sound_have_to_be_to_be_heard/
|
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"Can you clarify this? I'm sure others will have better responses, but do you mean that the transmitter of this sound wave is entirely through the atmosphere (as opposed to the ground?) Since we can hear earthquakes from all over the world quite well through the ground.\n\nIf you mean atmosphere, calculating the propogation of sound from one side of the world to the other would be pretty difficult since the amplitude you'd require would (I'd expect) go into a highly non-linear regime. As a first guess I would imagine requiring creating a large vacuum in a region and letting it implode, causing massive vibrations throughout the atmosphere.\n\nAs a point of reference even [the largest thermonuclear bomb set off](_URL_0_) didn't propogate a sound wave around the world. Someone correct this if I'm wrong please.",
"Krakatoa's last big explosion was heard 5000 km away and is estimated to have been 180 decibels.\n\n[_URL_0_](_URL_0_)\n\n > The sound of the eruption was so loud it was said that if one was within ten miles, they would go deaf.",
"Forgive me for not being a scientist, but until a true expert comes along, I think these answers are misleading. Each medium has a maximum volume, above which sound will distort and be expressed as a pressure wave. Our atmosphere will allow 194 decibels. Given the size of the earth and the range of human hearing, an explosion localized to one spot can't be heard as such by people on the opposite side of the planet.",
"Another question kind of goes along with this: Are there physical limitations to the amplitude of a sound wave? If so, you could probably extrapolate what a sound wave at the upper limit would do.",
"Well, let's make some assumptions.\n\nAssume that when a sound wave reaches the edge of the atmosphere, it does not bounce off, like it would a solid surface, but instead dissipates. Assume the sound wave will not change direction unless it comes in contact with a solid, or liquid barrier.\n\nAssuming this, it would be impossible for a sound to travel throughout the entire atmosphere without going through solid medium. So I'd guess the sound would have to be loud enough to cause the entire Earth to reverberate.\n\nI'm guessing you mean a specific sound, so I really don't think it would be possible for everyone to experience the same sound if it was the result of the Earth vibrating, since it's non-homogeneous, and the topography would affect many properties of the sound. But for everyone to hear the same event, a large enough asteroid could probably get the job done.",
"Sound eminates outwardly from the point of origin after which it will attenuate by 50% with every doubling of distance (inverse square law) not to mention it being reflected and absorbed by objects as it travels. The sound wouldn't bend around the earth either, and it would lose intensity fairly quickly, so it is unlikely that any sound generated at one end of the earth would be heard by people on the other side. "
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[] |
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"http://en.wikipedia.org/wiki/Tsar_Bomba"
],
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"http://en.wikipedia.org/wiki/Krakatoa"
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[]
] |
|
5toebp
|
the economics of the cost of private education.
|
How can a school survive when it charges $50k tuition but says the "real price" to educate a student is ~$90k?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5toebp/eli5_the_economics_of_the_cost_of_private/
|
{
"a_id": [
"ddnvkwq"
],
"score": [
2
],
"text": [
"What school is claiming that? For $90k you could get every student their own private teacher, a computer, and all the supplies they need and still probably have $10k left over. "
]
}
|
[] |
[] |
[
[]
] |
|
apjzep
|
how come noise cancelling headphones don't increase hearing loss when there is actually more sound being produced around your ears?
|
I understand that passive noise cancelling headphones are good for your ears because they have and insulant that keeps some of the sound from outside sources from reaching your ear.
What I don't understand is the active noise cancelling technology that records the audio on the outside of the headphones and produces sound waves of the opposite amplitude on the inside.
Wouldn't these extra sound waves exhaust your ears and potentially damage your hearing?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/apjzep/eli5_how_come_noise_cancelling_headphones_dont/
|
{
"a_id": [
"eg8zvk8"
],
"score": [
7
],
"text": [
"That's the whole point of the opposite amplitude, the two waves cancel each other out and the eardrum doesn't move at all as a result. So the additional sounds actually result in less movement of the eardrums, and thus are easier on your ears. People who work in noisy environments (like a data center), even if the volume isn't enough to be classed as dangerous, often eventually lose their hearing in the band of frequencies the sound was in. That's due to the cilia in the inner ear in that zone being worn away."
]
}
|
[] |
[] |
[
[]
] |
|
dgfxp9
|
Is there a maximum possible magnetic flux density?
|
askscience
|
https://www.reddit.com/r/askscience/comments/dgfxp9/is_there_a_maximum_possible_magnetic_flux_density/
|
{
"a_id": [
"f3bdw8k"
],
"score": [
7
],
"text": [
"There is the [Schwinger limit](_URL_0_): Above 4 billion T things get strange.\n\nAnd then there is the Planck magnetic inductance, 2\\*10^53 T. That's at least the maximum where our known laws of physics have a chance to work."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Schwinger_limit"
]
] |
||
1iruk7
|
Will listening to a recording of information while sleeping every night lead to me memorizing that information? Can the brain absorb information in a noticeable way during sleep?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1iruk7/will_listening_to_a_recording_of_information/
|
{
"a_id": [
"cb7ge43"
],
"score": [
7
],
"text": [
"_URL_0_\n\n > Since the electroencephalography studies by Charles W. Simon and William H. Emmons in 1956, **learning by sleep has not been taken seriously**. The researchers concluded that learning during sleep was \"impractical and probably impossible.\" They reported that stimulus material presented during sleep was not recalled later when the subject awoke, unless alpha wave activity occurred at the same time the stimulus material was given. Since alpha activity during sleep indicates the subject is about to awake, the researchers felt that any learning occurred in a waking state"
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Sleep-learning"
]
] |
||
5knfro
|
are more celebrities dying this year than average? or is it just observe bias or something?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5knfro/eli5_are_more_celebrities_dying_this_year_than/
|
{
"a_id": [
"dbp79zt"
],
"score": [
2
],
"text": [
"Statistically more celebrities are probably not dying more than in previous years, but there may be a connection based in how popular / unique these celebrities were."
]
}
|
[] |
[] |
[
[]
] |
||
jiklb
|
where do/did words come from?
|
Having just eaten breakfast, my 5 y/o niece is wondering who the heck came up with the word "banana," how it happened, how the rest of the world found out about the word, and this is how it works for all words.
Then she repeated the word "banana" until the word lost all meaning.
Thanks reddit! haha :)
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/jiklb/eli5_where_dodid_words_come_from/
|
{
"a_id": [
"c2cffdg",
"c2cffdg"
],
"score": [
9,
9
],
"text": [
"There are a *lot* of answers to that. Here are some:\n\n* Some people believe the first words were caveman grunts or warning calls. It's easy to see how \"gaaah!\" for \"there's a tiger coming, let's run!\" could become a word *meaning* 'tiger' or 'run'.\n* It's not interesting, but the main way a language gets words is taking them from other languages. Usually they get pronounced differently and might change so much down the years that they might not look like the original word anymore ('naranja' to 'orange', for example).\n* Words can change meaning over time. The word 'deer' once meant 'animal', but with time came to mean only one *kind* of animal. And the word 'hound' once meant 'dog' but now means only one *kind* of dog. A more current example is 'LOL', which once meant 'laughing out loud' but in just a few years has lost so much of that meaning that if you want to tell someone their comment made you laugh out loud, you won't type 'LOL', because it doesn't mean that anymore.\n* We'll make compound words - sticking two words together. Like 'blackbird', which doesn't meant any old bird that happens to be black in colour but a particular *kind* of bird.\n* We also have a lot of prefixes and suffixes, which are little bits you put at the beginning and end of words to change their meaning. So you have 'locate', but then you have 'relocate' and 'relocation' as well.\n* In English one thing we do a lot it take verbs and make them nouns or take nouns and make them adjectives, etc. You can 'chair' a meeting for example.\n* There are also words like 'radar', which is the first letter of five different words (an acronym) and words like 'brunch', where the head of one word is stuck onto the body of another (portmanteau words). But it's really, really rare for someone to just 'make up' a word and have it stick. ",
"There are a *lot* of answers to that. Here are some:\n\n* Some people believe the first words were caveman grunts or warning calls. It's easy to see how \"gaaah!\" for \"there's a tiger coming, let's run!\" could become a word *meaning* 'tiger' or 'run'.\n* It's not interesting, but the main way a language gets words is taking them from other languages. Usually they get pronounced differently and might change so much down the years that they might not look like the original word anymore ('naranja' to 'orange', for example).\n* Words can change meaning over time. The word 'deer' once meant 'animal', but with time came to mean only one *kind* of animal. And the word 'hound' once meant 'dog' but now means only one *kind* of dog. A more current example is 'LOL', which once meant 'laughing out loud' but in just a few years has lost so much of that meaning that if you want to tell someone their comment made you laugh out loud, you won't type 'LOL', because it doesn't mean that anymore.\n* We'll make compound words - sticking two words together. Like 'blackbird', which doesn't meant any old bird that happens to be black in colour but a particular *kind* of bird.\n* We also have a lot of prefixes and suffixes, which are little bits you put at the beginning and end of words to change their meaning. So you have 'locate', but then you have 'relocate' and 'relocation' as well.\n* In English one thing we do a lot it take verbs and make them nouns or take nouns and make them adjectives, etc. You can 'chair' a meeting for example.\n* There are also words like 'radar', which is the first letter of five different words (an acronym) and words like 'brunch', where the head of one word is stuck onto the body of another (portmanteau words). But it's really, really rare for someone to just 'make up' a word and have it stick. "
]
}
|
[] |
[] |
[
[],
[]
] |
|
7civ6o
|
To what degree did the Allies and the USSR cooperate in WW2?
|
I've been reading about the effects of the US and other nations supplying European countries and the USSR to defeat the Axis powers. They also shared SOME information on logistics.
Question: did cooperation between the Allies and the soviets make a difference in the outcome of the war? Would it have been worse for them if they didn't cooperate at all?
_URL_0_
It seems the Allies and the soviets were going to win anyways, but would the war have lasted longer (costing even more lives) if the two fronts didn't even talk to each other?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/7civ6o/to_what_degree_did_the_allies_and_the_ussr/
|
{
"a_id": [
"dpqle6n"
],
"score": [
2
],
"text": [
"They absolutely collaborated during the war, and while it's hard to say that they would have lost or exactly how the war would have been different, it would nevertheless have made the fighting substantially more difficult. I would say it's a misnomer to think of the USSR as separate from the Allies, because Soviet troops are such a critical aspect of the manpower needed to win the war. As early as 1941, even before the United States formally enters the fighting, Roosevelt insists that Lend-Lease supplies be sent to the Soviet Union as well, despite the fears of his advisors that the country will soon collapse. \n\nIn terms of war goods and materiel, the Soviet Union is the second-largest recipient of aid from the United States under Lend-Lease (behind Great Britain). In his memoirs, Nikita Khrushchev claimed that Stalin said the war could not have been won without aid from the United States, and Khrushchev endorsed this position as well (Memoirs of Nikita Khrushchev, 1918-1945, Volume 1). Even with the truly heroic efforts in Soviet industry to set up factories in the safe hinterland of the country, it still has tremendous need for just about every war good, on top of more ordinary but still vital supplies: trucks, jeeps, planes, and even food were all critical to keeping the war effort. Remember that with the loss of the Ukraine, the USSR had lost some of its most agriculturally productive lands, and American food kept the Soviet army fed at a time when every able-bodied man who could be diverted to the fighting was being sent. Richard Overy's Why the Allies Won gives a good sense of the sheer industrial scale that gave the Allies the edge and why their victory was inevitable, but that edge depended on very close collaboration between them.\n\nIn turn, the Soviets shoulder the greatest burden of the fighting against Nazi Germany for the majority of the war. Over a million Germans die fighting on the Eastern Front, and another million plus are captured, whereas just over 100,000 are killed fighting in France and Belgium throughout the war. Soviet troops make the victory possible, in part because Britain and the U.S. also are divided in fighting Japan, but mostly because the Soviets are stuck dealing with the German war machine. This produces tensions between the Allies, to be sure, because at Tehran Stalin demands and insists that a second front be opened up as soon as possible to take pressure off of his armies, which is in part why Churchill and Roosevelt are so insistent that maximum logistical support is diverted to the Soviets; they need to keep them in the war, and they worry about the possibility of Stalin concluding a separate peace with Hitler if he felt he didn't have a better option. But it also leads to American and British commitments to open a second front. After the Tehran Conference in 1943, they agree to a May 1944 (postponed to June) invasion of France, and that Stalin would time similar assaults in the East to tie down German forces and stretch them thin.\n\nThey also collaborate closely in the planning for a postwar world. Once the U.S. joins the war on top of supplying Britain and Russia, most rational observers understood that Germany had lost; in his memoirs, Churchill made it clear that once he heard the news of Germany's declaration of war, he felt that they had lost and they simply needed to be smashed into submission. As a consequence, they immediately begin planning for what a postwar world is going to look like. Some of that simply relates to occupation of postwar territories, like the division of Germany that's discussed at Yalta, but it also goes beyond. The Soviets participate in the Bretton Woods Conference in 1944 with America and Britain, which was aimed at stabilizing currencies to guarantee trade in the postwar period, which would in turn guarantee prosperity and prevent a recurrence of the war (Roosevelt in particular believed that the collapse of global trade had gone a long way in fueling the rise of dictatorships and the eventual war).\n\nIn short, not only did cooperation save lives and shorten the war, but actors on both sides understood they needed the other for the victory they wanted. \n\nSome useful reading...\nRobert Dallek, Franklin D. Roosevelt and U.S. Foreign Policy\nPaul Kennedy, The Rise and Fall of the Great Powers\nRichard Overy, Why the Allies Won\n"
]
}
|
[] |
[
"http://www.historynet.com/did-russia-really-go-it-alone-how-lend-lease-helped-the-soviets-defeat-the-germans.htm"
] |
[
[]
] |
|
6rajcm
|
How are we so sure about the fate of different types of stars when the Universe is not yet old enough for us to witness the death of certain stars?
|
For instance, according to [this Kurzgesagt video](_URL_0_), white dwarves have a lifespan of billions of billions of years.
But with the Universe being only a few billion years old, this would only be a split second in the life of a white dwarf. The Universe is not yet old enough for us to witness the death of any white dwarf, so how are we able to even throw out ballpark figures about their lifespans?
It'd be like a doctor predicting that a person will die at the age of 89 upon his/her birth when all similar persons are still alive.
|
askscience
|
https://www.reddit.com/r/askscience/comments/6rajcm/how_are_we_so_sure_about_the_fate_of_different/
|
{
"a_id": [
"dl48ju8",
"dl4geed",
"dl4n2l5",
"dl5hd16"
],
"score": [
13,
4,
2,
4
],
"text": [
"We're not absolutely certain, you're right. Observations would help us be more accurate, and there's a lot of detail we don't have, even hypothetically.\n\nHowever, all of our observations of white dwarves are pretty consistent: there are not continuing nuclear reactions happening there. Without anything adding energy, and by observing the current energy output, we can make some very good guesses about when they'll go dark. ",
"White dwarfs are already dead stars. The lifetime of a white dwarf is based on calculations from things like mass, temperature, rate of cooling, etc. Astronomers have documented the demise of other stars (most within other galaxies) and there are low mass stars, that based on calculations, will only \"die\" when the universe does. ",
"We haven't had time to observe much of the lifespan of any individual star, no. However, there are billions of stars observable to us in our galaxy of a wide variety of ages, masses. So while we can't watch, say, a 0.8 solar mass star progress through its life cycle on human time scales, we can observe thousands of such stars at different stages of their stellar evolution and combine that data with computer models that use theoretical physics to get a picture of the life cycle of the star.",
" > It'd be like a doctor predicting that a person will die at the age of 89 upon his/her birth when all similar persons are still alive.\n\nThe difference is that stars are much less complex than people, and are therefore far more predictable. We also have a huge sample size, so we have a massive ability to test our understanding of stars. And we find that all except a few very extreme stars really do fit our models exactly. These models only rely on a few parameters - mostly just the mass and initial metallicity (heavy element content) of the star - and predict the entire evolution of a star over its life-time based on those quantities.\n\nWe do only have a snapshot of stars \"frozen in time\", because human history is too short for much to happen in stellar evolution. But we can self-consistently explain basically all of the observed properties of all stars, and this gives us a huge confidence that our models are largely correct. There are sometimes weird things when stars are rapidly rotating or whatever, but these stars stand out as unusual objects that need more study, and only make up a small fraction of stars.\n\nThe situation here is very different to galaxies, which are more complex and dynamic, and can't be reduced down to a few parameters. But with stars, we really are very confident that our models are extremely accurate."
]
}
|
[] |
[
"https://youtu.be/qsN1LglrX9s"
] |
[
[],
[],
[],
[]
] |
|
b6cadm
|
the difference between the degrees and the warm/cold settings on a split system air-conditioner.
|
Long time lurker, first time poster to ELI5. Apologies if I haven't titled this correctly.
& #x200B;
I am working in a small office today and we have set the air-conditioner to warm and 22C. But my co-worker and I questioned what is the difference between 22C warm and 22C cold. We just thought 22C is just 22C.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/b6cadm/eli5_the_difference_between_the_degrees_and_the/
|
{
"a_id": [
"ejjf67j",
"ejjftuf"
],
"score": [
7,
2
],
"text": [
"Warm=keeping room temp above set temp\n\nCool=keeping room temp below set temp\n\nThe temp you set the thermostat to isn't necessarily going to be the room temp, it's just the temp that activates the system. ",
"22C cool tells the system that when the air temp goes above 22 the cooling system turns on to cool the air to 22C. \n \n22C warm is the reverse - it controls the heating system. \n \nSo if the system is set to 22C cool and the temp is **below** 22C, the heating system won't engage, **no matter how cold** the air gets."
]
}
|
[] |
[] |
[
[],
[]
] |
|
1cgdpq
|
Why are airships/blimps/zeppelins not used for transporting freight?
|
What sort of efficiency do they have? Do they leak (helium containment is difficult)?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1cgdpq/why_are_airshipsblimpszeppelins_not_used_for/
|
{
"a_id": [
"c9gf8id",
"c9glb1g"
],
"score": [
3,
3
],
"text": [
"Mostly for economic reasons. The leakage is not a major issue, as there are commerically operated airships right now. We used to fill these airships with hydrogen, but that went awfully wrong. Helium does not provide the same lift, is a lot more expensive, but easier to contain and does not react. There are some logistics problems too; maybe you want to fly a long distance with those airships, then you need some sort of ballast water recuperation system (otherwise you can´t sink). Also, lets face it, its not really that fast (but faster than cargo ships). \n\nThere was a german project, [CargoLifter](_URL_0_), that attempted to build a heavy lift airship that could hoist up to 160 metric tonnes. It was, however, an economical failure. \n\nThe efficiency is not to good either. Think of that massive hull, which creates a lot of drag. Drag is not good for any aerial vehicle (even going at low speeds).\n\nIn summary, the only real advantages over cargo airplanes are the size of the load it can take (virtually anything) and that it does not need a landing strip to take up the load. Anything else, I think it is not as good a solution as, say, a helicopter.",
"I remember seeing some stuff about this question about a half a decade ago in magazines like Popular Mechanics. Here is [one of those articles](_URL_0_).\n\nThe difficulties and drawbacks to blimps were well documented by game2genesis. To get around the problems of drag and ballast, new hybrid designs were being proposed that incorporated aerodynamic lift as well as the lift gases, thus just by speeding up or slowing down you could control your altitude. Stop moving forward and you \"gently\" float to the ground, no need for fancier ballast systems. I thought this idea was pretty fantastic, but I honestly have no idea what has become of it since the mid 00's."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Cargolifter_AG"
],
[
"http://www.popularmechanics.com/technology/aviation/airships/3764027?click=main_sr"
]
] |
|
1x3sps
|
What's happening in batteries when they seemingly run out of charge but hours later they have "residual charge" enough to power on again?
|
The rechargeable battery to one of my devices had died last night, couldn't power it on at all. Woke up this morning, tried to turn it on and it flickered to life briefly. What's up with that?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1x3sps/whats_happening_in_batteries_when_they_seemingly/
|
{
"a_id": [
"cf7w45b"
],
"score": [
4
],
"text": [
"The \"self-recharging\" features of batteries is most noticeable in a car battery. In some cases you can crank the engine until the battery seems totally dead, then come back an hour later and crank it again. The higher the drain on the battery (a car's starter motor is an incredibly high-drain device!), the greater the effect.\nTo understand why this happens, it is helpful to understand what's going on inside the battery. Let's take the simplest zinc/carbon battery as an example. If you take a zinc rod and a carbon rod, connect them together with a wire, and then immerse the two rods in liquid sulfuric acid, you create a battery. Electrons will flow through the wire from the zinc rod to the carbon rod. Hydrogen gas builds up on the carbon rod, and over a fairly short period of time coats the majority of the carbon rod's surface. The layer of hydrogen gas coating the rod blocks the reaction occurring in the cell and the battery begins to look \"dead\". If you let the battery rest for awhile, the hydrogen gas dissipates and the battery \"comes back to life\".\nIn any battery, be it an alkaline battery found in a flashlight or a lead acid battery in a car, the same sort of thing can happen. Reaction products build up around the two poles of the battery and slow down the reaction. By letting the battery rest, you give the reaction products a chance to dissipate. The higher the drain on the battery, the faster the products build up, so batteries under high drain appear to recover more.\nMany battery-operated appliances use two or four cells in series to create higher voltages. If one of the cells has a problem (for example, it does not dissipate reaction products as well as the other batteries), it can make all of the batteries appear to go dead. If you test the batteries individually, however, three of the four may be fine. If the batteries seem to go dead too quickly, testing all four batteries is a good idea. Throw out the bad one and re-use the other three."
]
}
|
[] |
[] |
[
[]
] |
|
3mz541
|
After splitting a magnet in half you cannot reconnect the two pieces back together at the original break point, why?
|
askscience
|
https://www.reddit.com/r/askscience/comments/3mz541/after_splitting_a_magnet_in_half_you_cannot/
|
{
"a_id": [
"cvjlway",
"cvjrn0o"
],
"score": [
9,
45
],
"text": [
"For most metals, it's because an oxidation layer forms once broken that prevents the metal from being reconstituted. There are ways around that, however, that involve stripping off that layer, applying a vacuum, and applying pressure that can rebuild the joint.",
"While the other answers aren't wrong, I'm pretty sure they are the wrong answer to your question. If i understand you correctly, you aren't asking why any old broken object doesn't fuse back together like they seem to be answering. Rather, you are asking why when a magnet breaks does it often have a repulsive force to realigning the fractured joint to how it was before. As opposed to the magnetic attraction holding the fractured joint together. Or like other fractured materials, like say a ceramic plate which many magnet break similarly too, which allows you to simply just line up the fractured joints to how they were initially. Nothing about it fusing the broken atomic bonds back together, just macroscopically lining up the fracture again. \n\n\n\nIt has to do with how a magnet works. Magnetic field lines always form close loops. They can't start nor end, you can't have a north pole without a south. For a standard bar magnet, the magnetic field lines leave the north pole, loop back through the surrounding space to the south pole, and then travel straight through the magnet to complete the loop. [As such.](_URL_0_) Any broken chuck of a magnet will have its own north and south pole, regardless of whether it came off the north or south end of the original. \n\n\nSuppose we have a bar magnet: \n\n\nNNNNSSSS\n\nNNNNSSSS\n\n & nbsp;\n\nAnd now we fracture it as so:\n\nNNNNSSSS\n\n~~~~~~~\n\nNNNNSSSS\n\n\nWe now have two bar magnets, and they still both have two poles. But, the thing to note is if you now try to attach them back together, you are trying to stick a N to a N and a S to a S. The magnets are going to want to twist 180 degrees to stick back together. Getting the original pre-fractured alignment back is going to be pretty hard, you'd have to really force it. \n\n & nbsp;\n\nNow on the other-hand, say we split the original bar magnet like so:\n\nNNNN ~~ SSSS\n\nNNNN ~~ SSSS\n\nYou'll note as i said before this is not valid, such a single pole magnet cannot exist. Really what happens is this:\n\nNNSS ~~ NNSS\n\nNNSS ~~ NNSS\n\nWe know have two bar magnets. You'll note that the fracture is even attractive. With ideal magnets of the right geometry and a perfect fracture in the right orientation, you could get the broken magnets that want to stick together exactly as before. \n\n & nbsp;\n\nIn real life, you aren't likely to get a clean fracture. You'll get some mix of both cases with jagged edges and such, they'll be some smaller more complex poles and fields going on. Even if like the second case, it's probably going to have some small repulsive or attractive force pulling it away from lining back up perfectly. As well, unless perfectly balanced it might be pulled into position where more poles can line up. Consider the second case, note how the one new N and S poles line up, but the outer N and S, which feel an attractive force, are far away from each other. Since the magnet can move in 3D, any slight imbalance or push and one is going to be pulled to on top of the other magnet into a folded version of the original. Simply put, if you break a magnet it's highly unlikely putting the fracture back together perfectly is going to be the most stable way for them to magnetically attach. \n"
]
}
|
[] |
[] |
[
[],
[
"https://upload.wikimedia.org/wikipedia/commons/thumb/0/0c/VFPt_cylindrical_magnet_thumb.svg/1024px-VFPt_cylindrical_magnet_thumb.svg.png"
]
] |
||
861cqc
|
why do pigments look like another colour when they’re a powder?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/861cqc/eli5_why_do_pigments_look_like_another_colour/
|
{
"a_id": [
"dw1r3aj"
],
"score": [
3
],
"text": [
"Well, I can't say I've noticed what you describe, but the explanation would be the following:\n\nLet's start with electromagnetic radiation: Electromagnetic radiation consists of electromagnetic waves, which are synchronized oscillations of electric and magnetic fields. It has a property called wavelength — the distance over which the wave's shape repeats.\n\nLight is actually a spectrum of wavelengths of electromagnetic radiation (as are radio waves, microwaves, x-rays and so on.. the difference between all of them is wavelength).\n\nWe can perceive a small part of that spectrum with our eyes - That part is what we consider visible light (some animals can perceive parts of that spectrum that we cannot, such as ultra-violet or infra-red). We can further break down that visible spectrum into individual colors - Each color is actually a slight variation of wavelength with red roughly at one end of our visible spectrum and violet at the other, going through every possible color in between. \n\nHere's a little graphic to better explain _URL_0_ \n\nNow the reason we actually see objects at all is because they mess with with the flow of these electromagnetic waves. The images we see are the waves bouncing off objects - partially off transparent objects and fully off opaque objects. \n\nThe reason we think objects have color is because the surface of the object can bounce the different wavelengths of visible light in slightly different ways - a particular surface might reflect a lot of the red spectrum of light, but little of the blue spectrum. Thus, that object appears to us as red because that's the part of visible light that gets to our eyes from that object. \n\nSo color is entirely determined by how a surface reflects electromagnetic radiation. It isn't red, it just reflects red light better than other kinds of light.\n\nThe explanation to your question, then, would be that those reflective properties are slightly altered when the powder is mixed with a liquid, resulting in a slightly different spectrum to be reflected back to our eyes.\n\n "
]
}
|
[] |
[] |
[
[
"https://tinyurl.com/ycbruzg5"
]
] |
||
2xovey
|
when the supreme court rules on gay marriage, what will happen to the lower court rulings, and the states, if the supreme court decides that states can constitutionally ban gay marriages?
|
I'm curious at what could happen if SCOTUS in June by some surprising 5-4 vote up hold bans on gay marriage. Would this effectively reinstate bans in every state where District and Circuit judges have ruled in favor of gay marriage? And if so, will marriages that have taken place in those jurisdictions still count? And what kind of administrative nightmare will this cause?
Edit: Title Gore! By "And the states", I mean there are states like Iowa where state courts have overturned bans on gay marriage. What would happen in those cases?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2xovey/eli5when_the_supreme_court_rules_on_gay_marriage/
|
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"In the past when a gay marriage ban has been lifted then applied again those who legally married still were married. It's possible this would happen nationally if the SCOTUS ruled that way. But further marriages would still be illegal where the state bans being considered had made them illegal.\n\nExactly how much of a hassle depends, but since in most of these places not having gay marraige was the norm forever, going back to that norm should be straightforward enough.\n\nThis wouldn't make gay marriage illegal in the states which haven't banned it though.",
"Let's assume that they say states have the right, then each state would get to decide to keep it or not. The states that have gay marriage would have to pass a law to stop it. The states without it already wouldn't really be affected unless they wanted gay marriage. \n\n"
]
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|
[] |
[] |
[
[],
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49c375
|
why is mp3's still ripped in 128kbp/s and not simply in either 320kbp/s or straight flac?
|
I have never understood this. Maybe it doesn't matter if you listen on some shit speakers like beats by dr dre or such but theres really no excuse anymore. Theres so much hd space available for cheap that the filesize really can't be an excuse anymore either.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/49c375/eli5_why_is_mp3s_still_ripped_in_128kbps_and_not/
|
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"Most people aren't audiophile nerds and 128kb/s is perfectly fine for listening with the cheap earbuds that 99% of the population uses. ",
"While hard drive space is irrelevant for desktops and laptops, it is still an issue for smaller devices like smartphones. The quality of MP3s is what people are used to, so it is still advantagous to stick to it.",
"I am not an audio expert, but where are you seeing 128kbps MP3s? Pretty much all of the digital music I've seen for purchase recently has been at least 256kbps.\n\nWhy 256kbps and not 320kpbs? Many feel that the difference between 256kbps and 320kbps cannot be distinguished by the human ear even under the best circumstances, let alone by typical listeners in typical situations.\n\nWhy not FLAC? Firstly, the reason above: the vast majority of people feel that there isn't a perceptible difference. Whether you feel the limit of what is detectable is 192 or 256 or 320, there is definitely a limit in the benefits of additional bitrate. If a FLAC file takes three times the space and no one can tell the difference in a blind test it's hard to justify the using that extra space. That said, if you feel that you can tell the difference, or just want the most \"pure\" version of the recording, there are services that will sell you a FLAC version.\n\nAnd the additional space does have some costs, even if they aren't as big of a deal as they used to be:\n\n* A lot of music is streamed: and while you may have a lot of space on your hard drive, a lot of people have much more limited bandwidth caps. Even over land lines many people still pay by the GB.\n\n* Some devices still have very limited space. The Apple Watch only has 2GB for music, and many people still run out of space on their phones, especially older ones.\n\n* There are additional encoding and storage costs for the music services as well, and when you are dealing with millions and millions of tracks the costs do add up. Perhaps not that significantly, but when you consider that 320kbps or FLAC is most likely an additional encoding, and not a replacement, it's just added expense for them.\n",
"Ripping from YouTube? Every time I tested I ended up with a 128kbps file",
"All of you are ignoring the fact that MP3 encoders have improved greatly over the years. A modern 128kbps track probably sounds just as good as a 256kbps or more track from the early 2000's. ",
"It's important to note that the sound quality difference between a lossless audio file and a 128Kb/s is so minute that less than 1% of people can really tell. To prove my point, take [this test](_URL_0_)\n\nFLAC is also not a well supported format (for instance, Windows Media Player won't add FLAC to the library without a plugin). It's also a very hyped format that people seem to think improves the quality (even when converting old MP3 files, which, obviously, it doesn't)\n\nThirdly, most MP3 files are at least 256kbps, a fair amount being 320. It's a well established format that perfectly balances quality and size. \n\nFinally, lossless formats are designed to be reprocessed, not used as the main format for storing files (plus streaming/playback will eat bandwidth and RAM), such as being remixed, remastered, enhanced, etc. Lossless formats are often saved many times during the production process which would eventually cause Quality loss in an mp3, but having the final product as an mp3 won't lose any real audio quality. Basically FLAC is a fad "
]
}
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|
6lajev
|
how does facebook (and other social media sites) compile a creepily accurate suggested friends list even when you are a new user and have given the site minimal personal information?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6lajev/eli5_how_does_facebook_and_other_social_media/
|
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"Using a mixture of IP addresses and cookies for identification purposes, throughout various websites and ads they keep track of and build a profile on you.",
"Phone contacts.\n\nOnce, i added to my phone a guy from other city (he was on vacation) and we didn't have friends in common.\n\nNext day, he appears on facebook as a friend suggestion.",
"Did you give them your phone number? Even if it isn't public, if some idiot installs the facebook app on their phone and has it in their contacts, facebook will link you. Same for email address - if someone has that in their phone's contacts or gave facebook access to their emails (e.g. has both the gmail and facebook apps installed).\n\nI recently saw someone from way far away with 0 friends in common who I have emailed a few times for something very specific and business-related as a suggested friend.\n\nFacebook actually [builds profiles on non-members based on members' data](_URL_0_) and then links the two if that person ever does join facebook.",
"A lot of ways. If you have the account signed in on your phone, it can read your contacts and find their Facebook accounts.\n\nAn obvious way: it looks at mutual friends.\n\nIf you use apps via Facebook, it could look at other people using those apps, people you've used it with and people nearby who've used it.\n\nIt could and probably does track the location of users (via IP addresses and GPS) and - if it finds you spend a lot of time with particular accounts - might consider that you were friends.\n\nIt might also buy data from Google, Yahoo or Hotmail about the people certain people email, and find accounts registered to your frequently contacted email addresses.\n\nFinally, it's unlikely but possible that if you create multiple accounts from the same computer, it will automatically associate them with each other.",
"One of the higher ups with the company I work for is always showing up in my suggested friends. He's not in my contact list at all. No phone number. No email. Nothing. We have no mutual friends. I don't have anything linked to my workplace on my profile at all. We don't even work out of the same building or the same city for that matter. I would really love to know how that works."
]
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||
khqen
|
why we use rms to express ac voltages
|
I understand DC voltages pretty easily. AFAIK "120v AC" means that circuit pushes out 120 volts just like 12v DC pushes 12 volts. But where and how does RMS factor into all of this?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/khqen/eli5_why_we_use_rms_to_express_ac_voltages/
|
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"I started to type up a complicated response to this, but then I realized this was ELI5. If you want the full answer Like You Are An Electrical Engineering Student I can actually explain the math behind it.\n\nBasically, an AC voltage is almost always less than its peak value. Think of a wave in the ocean, the peak value is like the top of the wave. A DC voltage of the same \"level\" would be flat and at the same height as the top of the AC \"wave\".\n\nIt turns out that an AC voltage with a *peak* the same as a DC one doesn't supply as much power, since the AC voltage is only at its peak. But, an AC voltage with an RMS voltage that equals a DC voltage will supply the same amount of power. So, the RMS value is kind of like a fancy average, that lets you think about AC power in a similar way to DC.",
"RMS = sqroot ( mean_value ^2 ) which is a useful average of a repeating signal.\n\nSo for AC voltages, since it is sinusoidal, the RMS = peak_voltage / sqroot(2). The reason to use RMS is because when dealing with AC stuff, usually people care about power, and average power follows the normal equations people are used to if you use RMS voltages and currents.\n\nP_instanteous(t) is still V(t) * I(t) but this depends on the phase difference, which depends on the complex load, and varies with time.\n\nP_avg = V_rms * I_rms which is easy to calculate and deal with.\n\nOne problem with AC is that because it alternates, if you look at one cycle of voltage, the average is zero. And in many ways the current is flowing out and then flowing back in, and also appears to be a net of zero, so how do you describe the real power being done (heat, light, work). \n\n115V (and/or 120V) is the rms value of the AC voltage. So if you have a 100 ohm resistor plugged into your wall, you can calculate the wattage (if you use average power and rms voltages), just like they were DC equations. ",
"AC voltage is expressible as a [sine wave](_URL_0_). The top part is positive, the bottom part is negative. If you add all the parts together over one entire period (two periods are shown in the picture) they add to zero. But we know from experience that AC can be used to do work, just like DC. \n\n[RMS](_URL_1_) gives the average over time, so this is what's used for calculations in electrical work.",
" > AFAIK \"120v AC\" means that circuit pushes out 120 volts just like 12v DC pushes 12 volts.\n\n120V RMS means that the constantly changing AC voltage ends up causing the same amount of heating to the wire (or, speaking in electrical engineering terms, \"carries the same amount of watts worth of power\") as a 120V DC signal would. But the actual DC peak of an RMS AC signal is actually 1.414 (sqrt(2)) times higher than the nominal RMS value. In the case of 120 RMS, 120 * 1.414 = 169. So if you use a DC multimeter and measure the light socket in your house, you'll see the DC voltage peaks up 170 volts( and down to -170 volts) for a tiny fraction of a second each time through the AC cycle.\n\nBTW, *don't* measure the light socket in your house with a meter, unless the meter is rated for 200V or more. Stick your el-cheapo 20V meter in there, and it'll blow up and put your eye out, or catch fire, or maybe just burn up its guts and die with a horrible nasty burned plastic smell. Don't say I didn't warn you.",
"I started to type up a complicated response to this, but then I realized this was ELI5. If you want the full answer Like You Are An Electrical Engineering Student I can actually explain the math behind it.\n\nBasically, an AC voltage is almost always less than its peak value. Think of a wave in the ocean, the peak value is like the top of the wave. A DC voltage of the same \"level\" would be flat and at the same height as the top of the AC \"wave\".\n\nIt turns out that an AC voltage with a *peak* the same as a DC one doesn't supply as much power, since the AC voltage is only at its peak. But, an AC voltage with an RMS voltage that equals a DC voltage will supply the same amount of power. So, the RMS value is kind of like a fancy average, that lets you think about AC power in a similar way to DC.",
"RMS = sqroot ( mean_value ^2 ) which is a useful average of a repeating signal.\n\nSo for AC voltages, since it is sinusoidal, the RMS = peak_voltage / sqroot(2). The reason to use RMS is because when dealing with AC stuff, usually people care about power, and average power follows the normal equations people are used to if you use RMS voltages and currents.\n\nP_instanteous(t) is still V(t) * I(t) but this depends on the phase difference, which depends on the complex load, and varies with time.\n\nP_avg = V_rms * I_rms which is easy to calculate and deal with.\n\nOne problem with AC is that because it alternates, if you look at one cycle of voltage, the average is zero. And in many ways the current is flowing out and then flowing back in, and also appears to be a net of zero, so how do you describe the real power being done (heat, light, work). \n\n115V (and/or 120V) is the rms value of the AC voltage. So if you have a 100 ohm resistor plugged into your wall, you can calculate the wattage (if you use average power and rms voltages), just like they were DC equations. ",
"AC voltage is expressible as a [sine wave](_URL_0_). The top part is positive, the bottom part is negative. If you add all the parts together over one entire period (two periods are shown in the picture) they add to zero. But we know from experience that AC can be used to do work, just like DC. \n\n[RMS](_URL_1_) gives the average over time, so this is what's used for calculations in electrical work.",
" > AFAIK \"120v AC\" means that circuit pushes out 120 volts just like 12v DC pushes 12 volts.\n\n120V RMS means that the constantly changing AC voltage ends up causing the same amount of heating to the wire (or, speaking in electrical engineering terms, \"carries the same amount of watts worth of power\") as a 120V DC signal would. But the actual DC peak of an RMS AC signal is actually 1.414 (sqrt(2)) times higher than the nominal RMS value. In the case of 120 RMS, 120 * 1.414 = 169. So if you use a DC multimeter and measure the light socket in your house, you'll see the DC voltage peaks up 170 volts( and down to -170 volts) for a tiny fraction of a second each time through the AC cycle.\n\nBTW, *don't* measure the light socket in your house with a meter, unless the meter is rated for 200V or more. Stick your el-cheapo 20V meter in there, and it'll blow up and put your eye out, or catch fire, or maybe just burn up its guts and die with a horrible nasty burned plastic smell. Don't say I didn't warn you."
]
}
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[] |
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|
1qvipm
|
This may be a dumb question, but if losing weight requires simply eating less calories than your body burns, what are the biggest differences from eating healthy or poorly?
|
If I understand correctly, if your body burned, say, 2500 calories a day, and you ate 2000 calories of fast food, you'd lose weight. If you ate 3000 calories of extremely healthy food, you'd gain weight. Obviously eating healthier food is better, but why exactly?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1qvipm/this_may_be_a_dumb_question_but_if_losing_weight/
|
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"This is complicated because your question isn't entirely clear. If by \"health\", you mean weight gain/loss, it is very hard to overeat truly healthy food. have you ever tried eating 3000 calories of meat and vegetation? your stomach and satiety hormones simply won't let you. healthier food also tends to impact insulin levels and sensitivity, controlling blood sugar and thus, hunger.\n\nIf \"health\" for you goes beyond just weight control, there are many vitamins and minerals that we must eat to maintain proper health, and junk food tends to be extremely low in these, as well as plant-based compounds that are very good for you (think fruit phytochemicals and leafy greens). \n\nwhile it is true that the sheer number of calories matters for weight loss, it is clearly easier and healthier to eat higher-quality foods for these calories than lower-quality ones.",
"It's definitely not a dumb question. \n\nSome things to consider/bear in mind:\n\n- Eating \"healthily\" is a poorly defined concept, and the many items can be both healthy in one regard and unhealthy in another (for example, the association of certain types of fats, omega-3's, with both improved metabolic health and a small increased risk of prostate cancer)\n\n- \"Healthy\" eating is invariably dependent on how much of a particular nutrient you consume; compounds in red wine improve cardiovascular (heart and circulation) health, but drinking 2 bottles a night won't make you healthy. \n\n- Certain classes of compounds worsen metabolic measures. For example, a type of fat compound very similar to the omega-3 fats (which are highly beneficial), the omega-6 fats, are linked to increased inflammation, which drives many disease states including obesity, diabetes and cardiovascular disease. Trans-fat consumption is even more strongly linked to these disease risks.\n\nIt's also worth saying that calorie content is not accurate for many foods, due to the method of estimation used. This often fails to accurately account for inefficiencies in digestion, which can, for example, be altered by the bacteria in the intestines (the microbiome). The [wiki article](_URL_0_) discusses some issues.\n",
"being healthy is not maximized by minimizing weight, thats the first point it guess, also every kind of \"unhealthy\" is only a matter of dosage. For example protein is considered healthy. But too much protein is unhealthy. Sugar is considered unhealthy but without it(or it being split out of more complex carbs) you have no short term energy. The only thing thats is kind of out of that principle is water since it can't be essentially unhealthy when consumed in mass but its unhealthy to consume too little. Also too little diversity in food can lead to not having enough substances to process certain types of food. I can't really describe this any better since english is not my main language."
]
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[] |
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[
[],
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"http://en.wikipedia.org/wiki/Atwater_system#Theoretical_and_practical_considerations_relating_to_the_calculation_of_energy_values"
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] |
|
7fjm2c
|
why does the us federal reserve want to raise intrest rates if unemployment falls below 4%?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/7fjm2c/eli5_why_does_the_us_federal_reserve_want_to/
|
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"The Fed has a dual-mandate: keep unemployment low and keep inflation low. Generally economists think that the US is at full employment if the unemployment rate is around 4%. This is because you figure that at any point in time you have about that many people \"frictionally\" unemployed. Meaning they are moving from one part of the country to another, want to change careers, just caught a bad break, etc. They are no unemployed because of it being systematically hard to find a job.\n\nOnce the economy hits full-employment, the Fed gets very worried about inflation taking hold in wages. If the economy continues to grow, employers will start bidding up wages even though there are no more people to hire. In essence, wages would increase without an increase in productivity, and thus inflation would be transmitted through out the rest of the economy. (This is essentially what happened in the 1970's and was a huge problem.) So they start raising rates to slow growth and prevent wage inflation. ",
"Moderate inflation is good for the economy as it results in more money to employees = > increased consumer spending = > increased production = > increase in GDP."
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5f6xej
|
how are not-for-profits/nonprofits allowed to pay their workers? isn't salary profit?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5f6xej/eli5_how_are_notforprofitsnonprofits_allowed_to/
|
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"Profit is made after all of your overheads and expenses have been paid, so wages/bills/insurance etc have to be taken cared for first. Anything else that is left is profit :)",
"No, profit is everything after expenses that normally goes into the pockets of the people who own the corporation and makes them wealthier. Non-profits are allowed to turn a profit, but they have to take that profit and re-invest it into the corporation to further its goals instead of handing that money out to the shareholders. ",
"Well, no, from an organization's perspective, salaries are an expense.\n\nBut the real reason it's not like that is that not-for-profit has a more specific meaning than you're thinking. The details aren't really ELI5 stuff (and besides, vary from country to country), but the basic idea is that a non-profit has a mission other than making money, and, if it does end up with more money than it started with, it doesn't distribute the gain back out to its owners.",
"Non-profit means that what's left at the end of the year (subtracting expenses from revenue) isn't given to owners as profits. Revenues are not profits, nor are donations in the case of a non-profit. And salaries are an expense for an organization, not a profit.\n\nTo illustrate, you have a business that makes $1 million revenue, and you have a non-profit that takes in $1 million in donations. Both spent $500k on salaries, rent, marketing, etc. At the end of the year, the business owner would pocket the remaining $500k as profit. The charity would use that $500k remaining to fund cancer research, or buy food for the poor."
]
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[],
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2kcts8
|
why do american's take halloween and costumes so serious? why is it such an important event in the year?
|
UK here. Can someone explain why Halloween holds such significance with Americans? Why they try so hard with costumes?
I fully understand why you would dress up in cool costumes as a kid trick or treating, but even adults go to great lengths to have the best costume at (for a non-American) a completely forgettable date on the calendar.
Thanks
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2kcts8/eli5_why_do_americans_take_halloween_and_costumes/
|
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"The simple answer is that it's fun. A lot of people like to get artistic with their costumes and have fun dressing up with family and friends.",
"It is not exactly important. It is a fun holiday where children get to dress up and go get candy and adults get to dress up and go to parties. A major part of dressing up is to have high quality costumes that you put effort into. It makes it more fun, particularly if you are crafting your own costume. ",
"Costume parties are lots of fun. It's pretty much a day where everyone is throwing a giant costume party. Im surprised it hasn't caught on in more places.",
"It isn't that serious. Most stores/banks/etc. are still open on Halloween. Really it is just a great time with the kids and has become tied to growing up in the US.",
"American here. I have no frickin' idea and it frankly skeeves me out. I am the Grinch of Halloween.\n\nTrick-or-treating -- OK, harmless fun, I get that, I did that. A costume party -- that certainly can be fun. But for me it crosses over into *no fun at all* when your bank teller becomes a witch and the kid bagging your groceries is Frankenstein, or when six houses on your block have mock cemeteries on the front lawn or corpses impaled on the fence.",
"It's a time that you are supposed to party, and enjoy life through the motions of death. it's acceptable to get drunk, have fun, and look as crazy as you want. There aren't very many rules, and anything that would be \"strange\" to wear into society is perfectly acceptable.\n\nSource: mid-twenties american male.\n\nEdit: you could say that I'm ignoring the more traditional roles, but i'm explaining it the way that most everybody that I know sees the holiday.",
"It's not important, it's FUN. \n\nWhy do people complain about fun thing in the world? \"But WHY are there trampolines?\"",
"The answer with a lot of these questions relating to American culture is usually = does it make some people a lot of money? If so, that's why.",
"Englishman here and I feel the pain. In many ways it'd be cool to have the same halloween culture over here but it never takes off other than for kids' parties and trick or treating.\n\nWhat I genuinely find annoying is how batshit mental Reddit goes for it, every other post is about a costume AND THEY'RE NOT EVEN SCARY. Not a single white sheet ghost or anything.",
"We don't have an entire house of our Congress dedicated to silly dress, so we have to take a more egalitarian and hands-on method to scratching that itch.\n\nThat said, there are many approaches to Halloween in the US. The people who consider it the high point of their year are rare, but they make for good TV and post to reddit a lot.",
"marketing. the underlying principle of everything American. ",
"Part of it has to do with shifting cultural norms in US society. As distinctly religious holidays like Christmas and Easter receive less attention due to a less homogeneous religious culture, the secular holiday (secular in how it's observed, not its roots) gets more attention because everyone can join in without feeling like an outsider.\n\nThis effect is amplified by both the mainstream media (which avoids the\"controversy\" of religious holidays like the plague) and sites like Reddit (where there's a strong and vocal atheist/non-religious segment) and the secular Halloween gets talked about far more than things like Christmas (or Hanukkah or Yom Kippur).\n\nPlus, other holidays don't have cool costumes you can show off."
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1uata8
|
what is happening when i can tell someone is looking at me from across a busy room?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1uata8/eli5_what_is_happening_when_i_can_tell_someone_is/
|
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"text": [
"was just speaking to a friend about this, also how is it that the reaction to this causes my eyes know how and where to look precisely into the other persons eyes once you know there looking at you in a reflex type manner.",
"Well, I'm certainly no expert on psychology, but what's probably happening has been around a lot longer than you or I, even our great great grandparents. Back when we were still primates living out in the plains, we would have to keep our senses tightened up and ready to go, because almost every situation was a life or death situation. That's why when something bad happens, people tend to overreact because we're switching back to our primal instincts. \n\nNow, imagine you're an early homo sapien, wandering around the plains, when all of a sudden you feel a fierce gaze burning into your senses. Without looking, you know you've made a mistake and wandered into another animal's territory. You make a mad dash into the trees and escape before you can get caught. That early sense of danger potentially saved your life. Now, imagine you didn't notice anything and continued to wander around, right into the angry animal. Now you're dead meat.\n\nOf course, nowadays we humans don't have to worry about lions pouncing out of the brush and eating us, but our brains are still hardwired to subliminally sense people's gazes without us even realizing we're doing so. Our brains simply aren't used to the fact we're not in immediate danger, and so it's always alerting us when we're perceived to be in danger.",
"You have this feeling, of not knowing what is behind you, many times. Most of the time, you take a quick glance, see nothing, forget all about it, and go on. Sometimes you see something, like someone looking at you, and you remember. As all you remember is the few times you glanced and saw something, then you think that you 'know when someone is looking at you'.\n\nThere is another thing that is going on - and it is related to the 'stopped clock illusion'. You can't see anything when your eyes are moving from one place to another, so your brain replaces that with what it sees when your eyes stop moving. So you look around, your brain drops the useless, motion blurred imagery, and you see what was there when your eyes stop moving. Someone else sees you turning around or looking up, and looks at you. Bingo - you see someone who appears to have been 'looking at you' - but in fact, was only reacting to what you just did."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
b1212j
|
Given that uranium 235 has a half life of 703.8 million years, now long would all nuclear weapons have to be left alone before they would be considered inert?
|
askscience
|
https://www.reddit.com/r/askscience/comments/b1212j/given_that_uranium_235_has_a_half_life_of_7038/
|
{
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"eikz7ns"
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"text": [
"The circuitry, chemical explosives, and probably even the structural integrity of the weapons would likely fail before the U-235 decayed to the point where it was no longer a viable weapon. It should be noted there are other long-term effects, esp. with plutonium, which \"self-irradiates\" and can affect its own composition over long periods of time. (Also, it should be noted that U-235 is not the only material used in weapons.)\n\nBut roughly. The uranium in a weapon is enriched to over 90% U-235. If that number falls below a certain threshhold, the weapon won't work as designed, and might not work at all. Let's say, somewhat arbitrarily, that if it became 75% U-235 it wouldn't likely work (it depends on the design; the Hiroshima bomb used 80% enriched material, and dropping that to 75% probably would result in a lower yield but still something since it was designed to create a situation with several effective critical masses in it; an implosion bomb that was basically creating one critical mass would probably not work at that low a value if it was made to work with +90% enriched material). That's 22% of the U-235 decaying, so 700 million years * 22% = ~150 million years. But this is a silly way to think about it in practical terms."
]
}
|
[] |
[] |
[
[]
] |
||
446mww
|
why do gas stoves start at the highest heat setting instead of the lowest?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/446mww/eli5_why_do_gas_stoves_start_at_the_highest_heat/
|
{
"a_id": [
"cznu4er"
],
"score": [
12
],
"text": [
"For lighting. The gas comes out at maximum so it will reach the pilot flame and ignite right away.\n\n"
]
}
|
[] |
[] |
[
[]
] |
||
1ojad6
|
how does land/property pass from public too private ownership?
|
I'm curious about how land originally passes from being owned by the state too being owned by individuals, In what circumstances is it allowed? Does it cost as much as buying from the market? Why doesn't the government sell more/people buy more? How are settlements formed when no-one private entity owns the land?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1ojad6/eli5how_does_landproperty_pass_from_public_too/
|
{
"a_id": [
"ccsh2j9"
],
"score": [
2
],
"text": [
"Unless the public body is prohibited from selling its land, it can sell it whenever it wants to. Generally governments try to stick to the market rate, unless there's an ulterior motive (like land redistribution in Africa, in which case it might be sold below market value). Government doesn't sell more because it generally tries not to hold too much excess land, because it generates costs without income or usage.\n\nWhen no-one owns the land, usage is possession, at least in 18th and 19th century political philosophy. In almost every modern state however, 100% of land is owned, and anything that is registered to a private entity is automatically the government's."
]
}
|
[] |
[] |
[
[]
] |
|
2req40
|
if we can do our own taxes online, why can't we register a new car, transfer a tag to a new vehicle online? or any other dmv task for that matter?? (besides issuing licenses...)
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2req40/eli5_if_we_can_do_our_own_taxes_online_why_cant/
|
{
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5,
3,
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"text": [
"Because the DMV didn't build a web portal and the IRS did. If you want to know WHY the DMV didn't build one....well that's a different question altogether.",
"In some states you can do many things online. It's up to your state's secretary of state to establish the procedures and set up a website that can do those things. This whole internet thing is still pretty new in terms of changing the way the government does things.",
"In Virginia I know you can do a few things online, I can update my registration and they'll mail me new stickers"
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
21xuwd
|
why it's legal for fox news to make stuff up and sell it as news?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/21xuwd/eli5_why_its_legal_for_fox_news_to_make_stuff_up/
|
{
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"text": [
"The step after regulating \"integrity\" is regulating free speech -- so it's a slippery slope.\n\nAnd in a sense, there is regulation. Rather was canned for what he did and the damage it caused to his company. If people decide they want the same out of Fox, they'll vote with their wallets.\n\nAlso, your question is entirely speculative, and based on the idea that you (or someone somewhere in charge) have more ability to determine truth over someone else. Also a slippery slope.",
"CBS took action against Dan Rather, not the government (now, George Bush could have taken action against CBS as a citizen for slander, but that's different from how I'm understanding your context of 'legality'). Fox News can call itself news and say what it wants as long as it's not infringing on others' rights or endangering the public safety.\n\nWhat I think you're talking about is intellectual honesty. CBS sided on the side of intellectual honesty (but firing Dan was more of a PR move).",
"The same reason CNN MSNBC and ABC news can make stuff up",
"Also, to differentiate the examples, there's usually a harsher line drawn for lying about facts than for manipulating facts. When you manipulate facts, like, say, making a [misleading chart](_URL_0_) or reporting your own talking points as \"news,\" that can certainly cause issues. But we usually think of the best way to handle those issues as more speech, not more court action. This is in part to avoid slippery slopes, and in part because it can be hard to tell the difference between \"manipulation\" and effective argument before the idea gets out into the wild. \n\nBy contrast, straight up lying about facts, like Rather did, is easy to identify as wrong before the fact, and really is best dealt with by just stopping the speech before it happens. It's still very dangerous to let government decide what can or can't go forward, but it makes sense for there to be a harsh response. "
]
}
|
[] |
[] |
[
[],
[],
[],
[
"http://mediamatters.org/blog/2014/03/31/dishonest-fox-charts-obamacare-enrollment-editi/198679"
]
] |
||
c4ihfp
|
what is the sun's spectrum and how does it work?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/c4ihfp/eli5_what_is_the_suns_spectrum_and_how_does_it/
|
{
"a_id": [
"erwt54k"
],
"score": [
2
],
"text": [
"Heated matter emits radiation. Most commonly as infrared radiation which we can't see but can feel on our skin. When the heat exceeds a certain value, it starts glowing red. Keep heating up and it becomes yellow, then white, which means that all visible wavelengths are emitted - like a very hot piece of iron. Knowing this, we can attribute the heat to the colour of the light: 5500 degrees Kelvin is daylight \"colored\" (this light colour temperature is printed on light bulb boxes). \n\nA perfectly black body would emit all wavelengths that come from this temperature. But atoms and molecules absorb very specific wavelengths. So while we know that a star of a certain temperature would emit a certain spectrum of so called blackbody radiation (which wouldn't absorb any specific wavelength), we can observe that certain wavelengths are missing from the expected spectrum.\n\nFrom the missing lines in the observed spectrum, we can deduce the presence of certain elements in a stars surface, which tells us a lot about that star."
]
}
|
[] |
[] |
[
[]
] |
||
53hj8n
|
Anthem Protests and Francis Scott Key's Third Verse. Is it actually racist?
|
Recently, Colin Kaepernick has come under fire for protesting the playing of "The Star Spangled Banner" at football games. One recent talking point in the controversy has claimed that the original third verse of Key's anthem refers to free blacks and slaves who fought for the British Army in America. The verse, in full, is below:
And where is that band who so vauntingly swore,
That the havoc of war & the battle’s confusion/
A home & a Country should leave us no more ?
Their blood has wash’d out their foul footsteps’ pollution./
No refuge could save the hireling & slave
From the terror of flight or the gloom of the grave,/
And the star-spangled banner in triumph doth wave
O’er the land of the free & the home of the brave.
The relevant lines are "No refuge could save the hireling & slave
From the terror of flight or the gloom of the grave."
However, to me, these lines refer to the Hessian mercenaries hired by the British in the American Revolution and the conscript armies fielded in the Napoleonic Wars/War of 1812. Hireling can refer to a free black hired for labor (it can refer to any hired, low-wage laborer or immigrant) but in this case it seems like a diminutive term used to disparage the British Army. Slave almost certainly refers to conscripts, as the British Army fielded thousands of them in America during the War of 1812.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/53hj8n/anthem_protests_and_francis_scott_keys_third/
|
{
"a_id": [
"d7t54gc"
],
"score": [
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"text": [
" > Slave almost certainly refers to conscripts, as the British Army fielded thousands of them in America during the War of 1812.\n\nThey also fielded thousands of freed slaves, who the Americans demanded be returned to their \"owners\" after the war. So it doesn't \"almost certainly\" refer to conscripts. It possibly refers to conscripts. Or can be read literally as being slaves, as freed slaves fought for the British."
]
}
|
[] |
[] |
[
[]
] |
|
2ch2f8
|
why is katsaridaphobia (fear of cockroaches) so common?
|
First of all-yes, I did a search and the [last post](_URL_0_) was not helpful.
I understand the common fear of snakes, spiders, tigers-all are dangerous and it's instinct to fear them. I also understand that there are really uncommon fears like rabbits or birds that don't need an explanation, those people are the exception to the rule.
However, *many* people fear the damn roach-myself included. I don't mind other bugs-just the roach! I know others who feel the same as me.
Why do we fear these harmless, stupid bugs?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2ch2f8/eli5_why_is_katsaridaphobia_fear_of_cockroaches/
|
{
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"text": [
"Cockroaches are generally considered a sign of uncleanliness, even squalor. That's not strictly true, but it's a connotation that has remained. They also carry diseases. Many things like this aren't even an instinctual fear. Babies reach for hot stoves. We *learn* over time that cockroaches are indicative of a poor situation. They're also really hard to kill, and nobody likes that. Darn things would survive a nuclear apocalypse. That's freaky.",
"Because they are miniature lovecraftian hellbeasts! I almost broke my ankle \"teleporting\" over the couch to get away from a palmetto bug (cockroaches bigger, uglier, even harder to kill cousin in the south) once. They are made of malice and hatred of people and will fly in your face for no damn reason. I tried to kill one once, \"kill it with Raid\" my husband said, \"It will die instantly\" he said reassuringly (from a safe distance over the phone)...it flew into my EYE covered in raid and then escaped. I was blind for like and hour and it got away scott free. Why are we afraid of roaches...because they are scary and have evil murderous hearts that won't quit beating until they have filled you with the maximum amount of rage-panic!! Ok, rant over.",
"If you've ever had to deal with roaches (and almost anyone who loves in a hot/humid place long enough has had to deal with them at least once in their life time) you know that they are built to be a nuisance to anything they cross paths with. And thats their only job, to be a nuisance. \n\nThey are fast, they are resistant to almost anything (I've seen man survive taking a boot to the head), they like to hide it the most annoying places, and they like to come out in the dark. Its not uncommon for a person to be uneasy in the dark because of the things they might be able to see but you know thats when roaches like to some out. So now you have to think about this things crawling all over the place in the dark. Turning the lights on isn't too much better because then you get to see them all scatter and how close they were to you, this understandable freaks a lot of people out. You might feel something brush across your leg and you don't know if its just your imagine or a roach, probably a roach."
]
}
|
[] |
[
"http://www.reddit.com/r/explainlikeimfive/comments/21y7qa/eli5_why_am_i_deathly_afraid_of_cockroaches_while/"
] |
[
[],
[],
[]
] |
|
9e5ybd
|
what's preventing me from randomly guessing someone else's software product key, especially for physical copies of stuff?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9e5ybd/eli5_whats_preventing_me_from_randomly_guessing/
|
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"text": [
"You seem to understand the concept of brute force. I think the reason it's not more common is just the amount of work that entails for relatively little gain. It would be more lucrative to use that program and computational power to guess windows keys or something more valuable than the new CoD DLC or whatever. But it does happen there are a number of \"cracked\" games where you use a keygen program as part of the install process. ",
"Actually, the numberspace is significantly smaller because with a 15 char key, the 15th is usually a check digit. So you just need to generate the 14 char combos and ensure you calculate the correct check digit for the last one.\n\nOther than that, it’s all up to the large numberspace to prevent collisions (just like with hashes).",
" > but first of all I could bring that number down by avoiding using obvious or simple compinations (e.g. QWERTY)\n\nLet us assume there is some sort of filter on the keys to prevent curse words from showing up. Or maybe any word at all, in any language which uses those characters. A couple million combinations ruled out then.\n\nHow many combinations can you get for a 15 character key that allows letters and numbers which are case-sensitive? That means each character can be one of 62 different possibilities and you are choosing 15 of them in a specific order.\n\nThe result is that there are about 7.689 times 10 to the 26th power different options. That is 768900000000000000000000000 different options. Your couple million filter doesn't make it much easier. Let us assume you make a copy of the game for every living person on Earth? Still absurdly tiny in comparison to the different possible options.",
"TL;DR: Nothing really, because the chances of you guetting a valid key is slimmer than winning the lottery. The number of invalid keys simply make any potential guess worthless, even in great numbers. It's the same with passwords. \n\nFor one the validation server might notice you trying thousands upon thousands of keys and deny you access, so that's one possibility. \n\nHowever, I don't think you actually understand how monumentally huge the number 35^15 is. It's a number that has 24 digits (not to mention most keycodes use both upper and lowercase, so it's more likely to be 62^15 or whatnot).\n\nLet me put it this way: let's assume that you have a computer that can make 100 million guesses every second. It will take that computer roughly 45 million years to manage to guess every single key. If we assume that there are a billion (10^9) different valid keys then your chances of guessing a valid key is for all practical purposes 0. \n\nIf you take 100 thousand guesses the odd of you getting NO valid keys, out of a billion, are 99.9999999%, essentially guaranteed failiure. \n\n\nIn order to get a 50% chance of finding ONE of the billion keys floating around you'd have to print 10^14 different codes. ten thousand billion guesses to have a 50% chance. \n\n\nIt's simply not practical in any sense of the word, even if there are more valid keys. This is also the philosophy behind \"your website password must be X characters long\". after a certain point, assuming you don't use an obvious password, it simply isn't practical with all the computing power in the world to randomly guess the correct answer. \n\n\n",
"You're grossly underestimating the difficulty of guessing a key. Let's go with your 37^15 probably, since that's a fair approximation. Now let's assume that we can knock out all the \"most common\" keys that are \"too easy\". That gets rid of 10,000 or so possibilities. Yay. But that still leaves HUNDREDS of TRILLIONS of possible keys. Assuming you can make 10,000 guesses per SECOND, on average it will take you approximately 10,000 YEARS to get a single hit. \n \nThat's what keeps you from randomly guessing a key, it's why Bitcoin wallets (and other forms of encryption for that matter) are so secure, etc. Statistically you have a significantly larger chance of guessing every number in the Powerball drawing ONE time over the course of your ENTIRE LIFE than you do of randomly guessing one out of 100,000 15-digit product keys.",
"Since its ELI5, there is nothing but raw chance that makes it so you can't do it.\n\nMore advanced:\nsay a computer takes 3 seconds to attempt a passcode, relay the information to the company, and get either a pass or fail response back:\n\nThe chances of you getting it correct are 1 in 3.3344626795e+23, or for simplicity sake, 330000000000000000000000 with a 15 character. Each time you do it AND FAIL, you don't say \"Now I have 2 out of x chances\" instead you have just the same amount of chance of getting it right. The law of large numbers says as we do more trials, the number of successes / number of attempts will slowly reach what is the true chance.\n\nEven assuming that somehow, we're guaranteed to get a hit at least be the bigNumber'th time, that's still on average bigNumber * 3 seconds.\n\nLets see how long one person takes to do it:\n330000000000000000000000 * 3 / 60 / 60 / 24 / 365 = 3.1392694e+16\nor 31,000,000,000,000,000 years (again, this is assuming we have the power to get average odds on demand)\n\nYou bring up that a single game has 100,000 copies sent out, so now we have many more times the chance to hit! \n\nNow we're down to 31,000,000,000 years of churning. \nThere are 15,624 games on steam (as of 2017, so data is a little old) and lets make it an even 15000 (some games are free!) \n31,000,000,000 / 15000 = 2,066,666 years of churning (assuming we just want one license)\n\nYou can have more computers working, so say we have 500 computers going all at the same time (avg cost of a computer is $700 so thats $350000) \n\n2,066,666 / 500 = 4133 years of constant work to get one game.\n\nAt that rate, its cheaper to buy a game."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[]
] |
||
2iqzlf
|
Is it in the nature of gravity to cluster things even in the largest scale?
|
recently I read that not only stars are clustered in galaxies, but also galaxies are clustered in galaxy-clusters. This made me think - is it in the 'nature' of gravity to make things arranged in clusters? Thus, just like there are cluster of galaxies, the galaxy-clusters themselves are arranged in clusters of galaxy-clusters, and so on.
|
askscience
|
http://www.reddit.com/r/askscience/comments/2iqzlf/is_it_in_the_nature_of_gravity_to_cluster_things/
|
{
"a_id": [
"cl4r9er"
],
"score": [
4
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"text": [
" > Is it in the nature of gravity to cluster things even in the largest scale? \n\nThe word *even* is inappropriate here, because the force of gravity almost only shapes the universe on large scales. It is to weak to have an relevant effect on small scales, like the nuclear forces have. So yeah, the gravity is responsible for things to clump together, because it's always attractive. Nuclear forces don't have the required range to do that. \n\nTogether with the electromagnetic force, which is responsible for things to shine and dark energy, something we have yet to reveal what exactly it is, gravity is responsible for the appearance of the mid-ranged and large scales of the universe. The gravity acts as an attracting force, the dark energy as receding force and the electromagnetic makes it al visible for us."
]
}
|
[] |
[] |
[
[]
] |
|
f6m1yo
|
how did someone as insane as nero become emperor?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/f6m1yo/eli5_how_did_someone_as_insane_as_nero_become/
|
{
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"fi5mssn"
],
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5
],
"text": [
"Nero was raised in a Roman imperial governance tutoring system after being adopted by Claudius. \n\nKeep in mind that when looking at the historic past, behaviour considered loathsome now was more common place then. Additionally, the tenets of human emancipation weren’t yet a thing so life was cheap and crimes were rarely held to account."
]
}
|
[] |
[] |
[
[]
] |
||
3yup9h
|
Why Were Chess Players in the 60s-70s Treated like Celebrities and Not in Todays Society?
|
It seems every movie i've seen regarding Bobby Fischer always showed him as a celebrity with Night Show appearances and News broadcasts, but today we hear nothing of the leading chess players. Why?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3yup9h/why_were_chess_players_in_the_60s70s_treated_like/
|
{
"a_id": [
"cygx7h8"
],
"score": [
21
],
"text": [
"Magnus Carlson is treated like a celebrity, even in the United States he make appearances on talk shows and news programs. In other countries he is even more well known. He makes well over a million dollars a year and has sponsors. \n\nBut the reason Bobby Fischer was so much more popular than Chess players in the United States today has to do with the cold war. Americans at that time did not beat the Soviets often in Chess. Bobby Fischer was the first naturalized citizen of the United States to be world champion. His world Championship matches were against the #1 ranked chess player at the time who happened to be a Soviet. \n\nThe fame of Bobby Fischer is the same reason many people know the name Mike Eruzione. For those who don't know him he was the captain of USA ice hockey team from the 1980 olympic games that beat the Soviets. \n\nMy source is a book titled \"Bobby Fischer: The Wandering King\". It investigates Fischer's FBI files and talks in depth about the importance of Fischer beating the Soviets to the USA. \n\nI also recommend the movie \"Pawn Sacrifice\" "
]
}
|
[] |
[] |
[
[]
] |
|
2xngf6
|
if scientists can tell that their best atomic clock loses 1s every 16 million year, why not use what ever they're using to measure the clock's accuracy as a clock itself?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2xngf6/eli5_if_scientists_can_tell_that_their_best/
|
{
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"text": [
"They're not measuring the atomic clock, they're using the science behind it to judge it's statistical likelihood of accuracy. They're measuring it's \"margin or error.\"",
"Also what can happen is that they actually make several clocks working by the same principle and see how much their time diverges. The idea is to correct for random inaccuracies, so one clock will go a bit faster while the other is a bit slower. If you compare the deviation you can measure the inaccuracy of the clock. \n\nExample: Take a few old spring-based clocks they will diverge a couple of minutes over a few days. If you take quartz-based clocks they might bring that down to seconds or less over a few days and if you take atomic clocks it will be very much less still... virtually nothing over a day but you can then extrapolate to a divergence of 1 sec in X years.",
"Apparently this needs to be a FAQ. [How did people know which clocks were the most accurate?](_URL_0_)\n\nTo re-explain, you don't need a Platonic True Clock to measure accuracy, because what accuracy means for timepieces is stability and consistency.\n\nIf you take 10 wristwatches, synchronize them, let them run for about a year, and synchronously stop them, they won't even agree on how many seconds have elapsed. If you take 10 atomic clocks, synchronize them, let them run for about a year, and synchronously stop them, they will agree on how many nanoseconds have elapsed, and their sub-nanosecond differences will be consistent with \"loses 1s every 16 million years\" (or whatever).\n\nIf you're initially developing atomic clocks, and they agree that precisely, but all 10 clocks say that the year is 5 seconds too long (exageration), that just means you need to recalibrate the atomic clocks (change how many oscillations counts as one second) based on your best existing non-atomic time sources. But now the calibration is long-since done and the second is defined in terms of a certain type of atomic clock."
]
}
|
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]
] |
||
blhqcn
|
Why does pressure relax tensed muscle?
|
askscience
|
https://www.reddit.com/r/askscience/comments/blhqcn/why_does_pressure_relax_tensed_muscle/
|
{
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],
"text": [
"Hello! I just wanted to let you know that I don’t have an answer, but that I did just read several reviews to see if there was an answer, and that surprisingly it’s still unknown how (and if) massages work on tensed muscles. This British Medical Journal review (_URL_0_) summarizes several studies on the matter, showing that there is a psychological benefit to massages but not really a physiological benefit - massages do make you feel better and less anxious, but don’t necessarily actually improve your health. Anyway, good question, and I’m surprised that I couldn’t find an answer for it!"
]
}
|
[] |
[] |
[
[
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1117024/"
]
] |
||
2rhw56
|
What primary sources do we have for the history of England prior to the Norman invasion?
|
I'm newly fascinated by the tumultuous period between the Anglo-Saxon invasion/settlement and the Battle of Hastings. What remains by way of primary sources from that time?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2rhw56/what_primary_sources_do_we_have_for_the_history/
|
{
"a_id": [
"cng2ysn",
"cngqhwk"
],
"score": [
3,
2
],
"text": [
"You'd probably like the [Anglo-Saxon chronicle](_URL_1_), which contains entries from the 9th-11th Century.\n\nThere's some other British annals as well - there's a [short list](_URL_0_) on Wikipedia (mods, I hope this is okay as a source?).",
"Life of King Alfred by Thomas Asser. Asser was a welsh monk in Alfred's court who was commissioned to write this biography. "
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Annals#Medieval",
"http://www.gutenberg.org/ebooks/657"
],
[]
] |
|
4ybtrq
|
Is oxygen distributed uniformly in a closed system?
|
I'm struggling to think of a real-world scenario apart from a stricken submarine with a finite supply of breathable air, but would the levels of oxygen in the atmosphere fall uniformly in all compartments (if all internal hatches were open) or would there be pockets of *more breathable* air in areas that were unoccupied?
As a fan of sci-fi I've always wondered about the "life support is offline, oxygen levels falling" trope, especially in a large starship or space station. Would the hero be better off roaming the ship rather than slowly passing out in the captain's chair?
|
askscience
|
https://www.reddit.com/r/askscience/comments/4ybtrq/is_oxygen_distributed_uniformly_in_a_closed_system/
|
{
"a_id": [
"d6nhuda",
"d6njhxf"
],
"score": [
4,
2
],
"text": [
"It would ultimately diffuse uniformly, but if you have people respirating the whole time, then it would depend on the volume of air, the total rate of oxygen consumption, how the people are distributed, and whether diffusion is being aided by things like fans and people moving around.\n\nThis is actually a problem in human spacecraft - active circulation is needed to avoid CO2 bubbles accumulating around people's heads when they're not moving around.",
"If the air is being disturbed, it'll be as close to uniform as matters.\n\nIf the system is under gravity and the air is perfectly still, it will eventually settle out with the more massive gases being more concentrated the lower you go, and vice versa. They of course don't separate out perfectly like the oil and vinegar in your salad dressing, but the concentrations do change."
]
}
|
[] |
[] |
[
[],
[]
] |
|
8v3u1w
|
The usual test for a witch was to drown them, if they floated they were a witch if not they were dead. What was the origin of this test and were there ever any cases in which the “witch” actually floated?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/8v3u1w/the_usual_test_for_a_witch_was_to_drown_them_if/
|
{
"a_id": [
"e1kj7eq"
],
"score": [
4
],
"text": [
"There is always more to write, but in the meantime you might want to check out this answer I wrote about Trials By Ordeal that discusses the \"trial by water\".\n\n_URL_0_"
]
}
|
[] |
[] |
[
[
"https://reddit.app.link/KiQ70SNcbO"
]
] |
||
6i0vjx
|
What was life like for a university student in the 1650s?
|
Not only in terms of education, but how they spent their free time compared to univerity and college students today.
Edit: In Western Europe, preferably as is the customary focus of world history.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/6i0vjx/what_was_life_like_for_a_university_student_in/
|
{
"a_id": [
"dj34157"
],
"score": [
17
],
"text": [
"I don't have an answer but a clarifying question... What country or region are you asking about?"
]
}
|
[] |
[] |
[
[]
] |
|
jrap5
|
why food cools off faster in my 98.6 degree mouth than at room temperature.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/jrap5/eli5_why_food_cools_off_faster_in_my_986_degree/
|
{
"a_id": [
"c2ehl3x",
"c2ej78r",
"c2ehl3x",
"c2ej78r"
],
"score": [
5,
2,
5,
2
],
"text": [
"because air does not conduct heat as fast as water (or your saliva) does. ",
"Both the air and your saliva are made of tiny parts called molecules. Heat is actually the back-and-forth motion of those little parts. The molecules that make up your saliva are closer together than the ones in air, so a lot more of them touch the molecules in the food when it's in your mouth instead of surrounded by air. The food molecules cool faster then because they have more molecules to bump into to slow them down.",
"because air does not conduct heat as fast as water (or your saliva) does. ",
"Both the air and your saliva are made of tiny parts called molecules. Heat is actually the back-and-forth motion of those little parts. The molecules that make up your saliva are closer together than the ones in air, so a lot more of them touch the molecules in the food when it's in your mouth instead of surrounded by air. The food molecules cool faster then because they have more molecules to bump into to slow them down."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
lxik2
|
what digital technology is and how it differs from whatever we used (analog?) before it
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/lxik2/eli5_what_digital_technology_is_and_how_it/
|
{
"a_id": [
"c2wdq1r",
"c2why8h",
"c2wdq1r",
"c2why8h"
],
"score": [
3,
3,
3,
3
],
"text": [
"Both technologies use electronic circuits, but digital ones have 'digital' data running through it. \n\nA signal running through a wire can be high or low. When it's high, we say that it represents the number 1 and when it is low we say that it represents the number 0. This is digital (digit-al) data since a combination of these values can represent whatever we want, eg time, symbols, letters. Say for example, we decide that 3 high signals represent the letter 'A', or when all signals are low then it represents midnight.\n\nWe then use these little components called Transistors. These are good at manipulating digital signals. Using these, we could make a component that takes incoming signals and adds them together to make a simple calculator. And then by making more elaborate components and circuits, we develop computers which can manipulate digital signals in all sorts of ways like calculate the motion of a bullet in a video game.\n\nPrior to this, electronic technology had no real concept of digital data. You would have electrical signals running through them, but they would function on the basis of more rudimentary processes.\n",
"Source: College Digital Systems Design Course\n\nWhat is digital?\n\n* A mode of transferring data by electrical voltage by the use of two states (0 and 1)\n\nWhat is analog?\n\n* A mode of transferring data by electrical voltage with a continuous signal\n\nWhy use analog?\n\n* You can model complex functions with few transistors\n\n* Low power consumption\n\nWhy not use analog?\n\n* Circuit complexity is limited by noise\n\n* Analog designs require more skilled designers\n\n* Limited amount of reuse or design automation\n\n* Does not scale down well (to nanometer size, for example)\n\n* Hard to test\n\nWhy not use digital?\n\n* Requires thousands of transistors to do simple functions\n\n* Requires more power\n\nWhy use digital?\n\n* Highly immune to noise and component variation\n\n* Same result every time\n\n* Reliable circuits with millions of transistors\n\n* Reusable designs\n\n* Designers require less knowledge\n\n* Scales down to nanometer size\n\n* Easy to test\n\nIf you'd like me to elaborate on any of these points, feel free to ask.\n\nFor example, I mentioned noise in analog and digital circuits. If there is any interest, I'll go into more detail on why this is a big deal.",
"Both technologies use electronic circuits, but digital ones have 'digital' data running through it. \n\nA signal running through a wire can be high or low. When it's high, we say that it represents the number 1 and when it is low we say that it represents the number 0. This is digital (digit-al) data since a combination of these values can represent whatever we want, eg time, symbols, letters. Say for example, we decide that 3 high signals represent the letter 'A', or when all signals are low then it represents midnight.\n\nWe then use these little components called Transistors. These are good at manipulating digital signals. Using these, we could make a component that takes incoming signals and adds them together to make a simple calculator. And then by making more elaborate components and circuits, we develop computers which can manipulate digital signals in all sorts of ways like calculate the motion of a bullet in a video game.\n\nPrior to this, electronic technology had no real concept of digital data. You would have electrical signals running through them, but they would function on the basis of more rudimentary processes.\n",
"Source: College Digital Systems Design Course\n\nWhat is digital?\n\n* A mode of transferring data by electrical voltage by the use of two states (0 and 1)\n\nWhat is analog?\n\n* A mode of transferring data by electrical voltage with a continuous signal\n\nWhy use analog?\n\n* You can model complex functions with few transistors\n\n* Low power consumption\n\nWhy not use analog?\n\n* Circuit complexity is limited by noise\n\n* Analog designs require more skilled designers\n\n* Limited amount of reuse or design automation\n\n* Does not scale down well (to nanometer size, for example)\n\n* Hard to test\n\nWhy not use digital?\n\n* Requires thousands of transistors to do simple functions\n\n* Requires more power\n\nWhy use digital?\n\n* Highly immune to noise and component variation\n\n* Same result every time\n\n* Reliable circuits with millions of transistors\n\n* Reusable designs\n\n* Designers require less knowledge\n\n* Scales down to nanometer size\n\n* Easy to test\n\nIf you'd like me to elaborate on any of these points, feel free to ask.\n\nFor example, I mentioned noise in analog and digital circuits. If there is any interest, I'll go into more detail on why this is a big deal."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
7oc5lx
|
Why do some vaccines use live viruses over dead (inactive) ones?
|
askscience
|
https://www.reddit.com/r/askscience/comments/7oc5lx/why_do_some_vaccines_use_live_viruses_over_dead/
|
{
"a_id": [
"ds8fifc",
"ds8ie1g",
"ds92yb2"
],
"score": [
2,
8,
2
],
"text": [
"This might not be the proper answer, but from what I understand is that if it has a live virus, that virus is generally in a weakened state. With a weakened virus, the virus is still able to do stuff, but it also allows your immune system to learn how to fight the virus better",
"Live vaccines generally create a stronger and longer lasting immunity. Because they contain a living but weakened form of the pathogen, they need to be refrigerated and handled with great care. Because a live pathogen is present in the vaccine, there is a greater risk of adverse reactions in some individuals compared to inactive vaccines.\n\nInactive vaccines generally, but not always, provide less immunity and can also require several booster shots over the course of a lifetime. The advantage of inactive vaccines is they're generally much easier to store/transport and can have less side effects for some individuals compared to live vaccines.",
"It depends on specifics. There are some antigens which the immune system reacts so strongly to that it doesn't matter whether or not dead or live viruses are used in vaccines. For others it takes a lot more work to coax the immune system to mount a response and develop the various cells which will provide ongoing active immunity, and that requires the presence of a live virus."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
26ohjm
|
why doesn't society like loners?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/26ohjm/eli5_why_doesnt_society_like_loners/
|
{
"a_id": [
"chsyp9n",
"chsys53",
"chsyvzp",
"chszb7g"
],
"score": [
2,
2,
3,
2
],
"text": [
"This is because the people that talk in public are extroverts. An introvert isn't as likely to take a public stance on any of this, so we have less of a defense.",
"I'd say it has to do with the fact that humans are pack animals, we live in flocks and are sociable creatures. Those who don't fit into that structure of being a part of the flock are left out.",
"Why don't loners like society?",
"This has been deleted because it is asking for opinions, it is not a subject that can be objectively simplified into layman's terms. Because of this, it belongs in /r/askreddit rather than here. Thanks."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
9zgs5e
|
why can’t people sue internet and financial companies for data breaches and why aren’t people behind bars?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9zgs5e/eli5_why_cant_people_sue_internet_and_financial/
|
{
"a_id": [
"ea90u74"
],
"score": [
16
],
"text": [
"Your premise is false. People can, and do, sue companies for data breaches. In fact many companies buy special insurance just for this issue."
]
}
|
[] |
[] |
[
[]
] |
||
3k4o9i
|
How did the Holocaust affect the field of psychology and philosophy?
|
I'm thinking primarily of Western thinking, but as it was such a global tragedy, maybe it also affected non-Western thinking as well?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3k4o9i/how_did_the_holocaust_affect_the_field_of/
|
{
"a_id": [
"cuvfu21",
"cuydcpt"
],
"score": [
10,
3
],
"text": [
"The persecution of Jews in Germany and the Holocaust had several distinct effects upon psychology: a major geographical shift in the epicenter of the scientific psychology world, an influx of Jewish psychologists into American universities, and a major change in focus from behavior to social issues. Prior to that time, behaviorism dominated American psychology in both clinical and experimental subfields, and the influx of Jewish refugees into America had a pronounced effect upon research and practice.\n\nPrior to 1933, Germany was arguably the center of the psychological world. The first scientific laboratory and academic department of psychology was founded in 1879 by Wilhelm Wundt at the University of Leipzig, and knowledge of German was considered essential for scientific literacy in the field, even in America. In advance of WWII, numerous psychologists fled Nazi Germany, with most settling in America. When Hitler rose to power in 1933, Jewish scientists were removed from academic posts. The most prestigious psychology post in Germany was held by Wolfgang Köhler, who was associated with the Gestalt school. Although not Jewish, he was a vocal opponent of Nazi ideology and wrote an article in 1933 that is considered to be the last published criticism allowed by the Nazi regime in Germany. After refusing to begin lectures with the Nazi salute, Nazi officials began harassing his students, leading him to resign. Köhler was also editor of the influential journal Psychologische Forschung (Psychological Research), which Hitler suspended. Köhler resumed editing it from Swarthmore College after emigrating to the U.S. in 1935.\n\nKurt Lewin was a Jewish psychologist associated with the Gestalt school in Germany. He was forced to leave the country in 1933 and turned his attention from perceptual phenomenon to studying the behavior of individuals in groups. He is widely considered to be the founder of the modern subfield of social psychology. According to Elliot Aronson, one of the main themes in post-war social psychology was to combat the idea that “crazy things are caused by crazy people.” The public largely believed that a flaw in the German character was responsible for the Holocaust, and it could not occur anywhere else. The 1950s and 1960s became one of the most productive periods in experimental psychology, as numerous researchers published studies that cast doubt upon the theory of the “Nazi mind.”\n\n* Muzafer Sherif was a Turkish psychologist who was jailed for speaking out against the Nazi regime. The U.S. state department arranged for his release to America in 1944, where he conducted a series of experiments known as the Robber’s Cave studies that demonstrated that arbitrarily dividing people (in this case, children at a boy’s camp) into groups creates ingroup favoritism and outgroup derogation sufficient to lead to aggression. \n\n* Soloman Asch was a Polish psychologist of Jewish descent who had immigrated to the U.S. in 1920. In the 1950s he published numerous influential studies of group conformity and propaganda.\n\n* Stanley Milgram, a student of Asch, was an American born Jewish psychologist who was inspired by the trial of Adolf Eichmann to conduct a series of experiments on obedience to authority in the 1960s. His first published study demonstrated that the majority of people can be induced to administer lethal shocks to a complete stranger. This publication came out right as the war crimes trials shifted from the leaders to the low ranking individuals who carried out the actual killings, and had a significant impact upon the public interpretation of what had occurred. \n\n* Leon Festinger, a student of Lewin, was an American born Jewish psychologist developed one of the most important theories of psychology, cognitive dissonance theory. The theory proposed that people experience physiological discomfort when they behave in ways that are inconsistent with their attitudes. In situations where they do not have complete control over their own behavior, they will avoid information that calls attention to this conflict and in some circumstances will revise their attitudes so that they are consistent with behavior. \n\n* Stanley Schachter was an American born Jewish psychologist who developed a theory that emotions are comprised of two factors: nonspecific physiological arousal and a cognitive interpretation derived from environmental cues. Because the cognitive explanation for arousal is malleable, strong emotions can spill over very easily to each other: an experience of terror can directly lead to fanatical devotion, the exuberance of a rally can lead to aggressive hatred, etc.\n\nThe field of clinical psychology was also strongly shaped by refugees and Holocaust experiences. Psychoanalysis was almost entirely in the domain of Jewish central European psychiatrists (Carl Jung, a non-Jew, was the only notable exception). Refugees fleeing Germany gave psychoanalysis a much wider audience than it had received up until that point. Simultaneously, the U.S. military and Veterans’ Administration began to initiate psychologists in the practice of psychotherapy due to a shortage of psychiatrists, and many of these new entrants choose to practice using a psychoanalytic approach. Several new therapy approaches were also directly informed by Holocaust experiences. Viktor Frankl, an Austrian psychiatrist who survived imprisonment at Auschwitz and Dachau, noticed that a prime determinant of who survived and who died was the person’s sense of their life having meaning. He developed a new therapy approach, logotherapy, from these experiences. \n\nI would highly recommend Richard Overy’s (2014) “Ordinary Men, Extraordinary Circumstances: Historians, Social Psychology, and the Holocaust” (Journal of Social Issues, 70, 515-530) and Robert Prince’s (2009) “Psychoanalysis Traumatized: The Legacy of the Holocaust” (The American Journal of Psychoanalysis, 69, 179-194) for further reading.\n",
"I can answer the philosophy side! Sorry if it's too late! I am a political philosopher so hopefully I can provide something up to standard. I will focus on western philosophy and more particularly France and Germany (I am less knowledgeable on the UK and the US but they also do a very different type of philosophy).\nOh Boy. Holocaust and philosophy. I should start by saying that nothing could be done on the subject I think without 3 volume of 1000 pages each! \nIt is astounding how philosophy was affected by the Holocaust and I will tell you why: Philosophy was going on with the assumption that NOTHING as bad as the Holocaust and more broadly World War II would ever occur. It is not that philosophers did not believe it would occur or not but instead that the intensity of the horror was never seen before and challenged many things that were discussed in philosophy up to this point. Everything that the Holocaust represents was a big middle finger to philosophy; particularly in three fields: philosophy of history, ethics, and political philosophy. It is a daunting task to really have an in-depth discussion on the topic through this medium but I will do my best and you can ask questions if you want more.\n\nPhilosophy of History: In the field of philosophy of history, a lot of what has been discussed so far has been teleogical. Coming first through Christianity and then through figures such as Kant, Hegel and Marx, history was seen as linear; as progressing. In the Christian sense, it would range from the birth of Christianity (return of Christ) to the Apocalypse and the Kingdom of God. In a Christian sense, it means that there are an Alpha and an Omega; a beginning and an end. Now, philosophers do not talk of the linearity of history in necessarily the same sense as an historian. Philosophers are interested in the perception of progress. Historians have to avoid discussing the linearity of history and make sure it does not taint their research but philosophically, the philosopher is not in a position in which he can ignore the appearance of progress. That things seem to somewhat become “better” to the uneducated man (as in anyone observing the world outside of his research mentality) needs to be addressed. So for Hegel, something such as war and peace, are two facets of society that in their seemingly conflictual relationship allow humans to achieve a greater understanding and attain Truth. Although I schematize Hegel dramatically here and oversimplify it, the idea is basically that history progresses through dialectical concepts allowing humanity to uncover its true rational nature. Most thinkers of the Enlightenment certainly had similar thoughts regarding the world and many argued that those philosophers simply “secularised” Christianity’s conception of history. \n\nMarx is just as bad; although Hegel is an idealist, Marx is a materialist and will instead propose that the progression of history is material (who owns the means of production etc.) but once again, Marx is still in this conception of linear history. It is quite obvious in both Marx and Hegel in the way they address different time periods and how Marx thinks that were are slowly moving toward the final stage: communism. \n\nThen comes WWII. How can you discuss a linearity of history; the world getting better when there is the Holocaust? It suddenly made no sense whatsoever. Even if humans discover their own selves as time goes by through their intellectual experiences, how can something such as the Holocaust be part of any linear conception of history? Although Marxism was still strong after WWII, it became glaringly obvious that there were issues with Hegelian philosophies. Although philosophers had pointed issues before, those issues were essentially philosophical in nature. The Holocaust was truly the horrible moment of human history that led to radical changes in how we perceived history from a philosophical point of view. This leads me to the second point: ethics and challenging the Enlightenment.\nFor many philosophers, the Holocaust could only be explained by issues stemming from the Enlightenment. More specifically, religion and science.\n\nIn the case of religion, the argument is not that because there was no religion, people became Nazis and killed jews. More so that it allowed for a conception of the world in which the State is central to take place and to elevate the “body” to the level of religious. Nazi ideology put a strong emphasis on the body, appearance, being physically fit: in other words, making the object of worship something wordly; of this world. The violent rejection of religion while liberalism was weak (a lot of literature on the links between religion and liberalism but I don’t want to make this longer than it is already) allowed for a counterbalance in which the supremacy of the body took place; something we do not see in Christianity, Enlightenment ideals or Liberalism. This goes hand in hand with the will to permeate society with science. Nazi ideology of course placed a strong bond on making their ideas “scientific”. Careful here: many will point out Nazi rejected many sound science and the like but that is missing the point being made: that Nazis wanted a systemised construct of knowledge to found their principles. It is why they based so much of their ideas on bloodlines, artificial selection and the like. This led to philosophers such as Levinas to put forth ideas regarding a healthy relationship with the body. Liberalism, Christianity and the like focused too much on the mind at the expense of the body; the Nazis did it the other way around. For Levinas, the physical had to be reconciled with the mind and proposes an ethics based around the acceptation of the Other’s alterity when presented with the Other’s physical presence. Levinas was not just anyone: he was a Jewish philosopher who lost his family in the camps and was himself stuck in one for most of WWII. And many philosophers following WWII had to revisit philosophy as a field to account for the Holocaust. The intellectual roots of the Holocaust had to be studied and altered deeply the philosophical landscape. \n\nAlthough Levinas is more in the field of metaethics, ethics as a field was of course affected. As discussed by my colleague who is a psychologist, many of the experiments and events during the Holocaust changed our perception of how much should we expect from society. Clearly, society did not revolt or defend people and experiments such as Milgram show that we must revisit the moral burden philosophical theories put upon people. Philosophers such as Kant would put a heavy burden on the moral agent and the Holocaust led ethicists to revisit the burden placed upon moral agents. On the utilitarian side, there was of course the obvious idea that clearly, the worst we fear from utilitarianism is not impossibility anymore. Humans could truly kill a staggering amount of people for the greater good. Although John Stuart Mill’s utilitarianism was more centered about what rules produce the greater good, the Holocaust showed that things could be fiddled with toward certain conception of the greater good and that clearly, ethics had to become a more practical field. And so, it did, gradually in philosophy departments, become a much more important part of ethicists.\nLast but not least: political philosophy. Political philosophy saw of course the rise of liberalism as something to be obvious. The horrific acts of the Holocaust and WWII more broadly moved fascism out of the way; anarchism was now also a lot less significant following defeats in Spain and Russia. Liberalism became opposed to Communism and so, the cold war begins. In that regard, the Holocaust made liberalism a pressing issue because for many, it demonstrated the necessity of many precepts put forth by liberal thinkers as to avoid a treatment of the minorities similar to the Holocaust. We did not exactly fear that the same thing would happen in the UK or Canada but more so that philosophically, it became obvious that a philosophical system like liberalism would avoid many pitfalls of fascism. WWII allowed also liberalism to take a solid hold following the defeat of Germany in intellectual communities with its only grand opponent being Marxism. \nI will stop for now but if you have any questions, I can certainly elaborate! It is a very complex topic and I am on a mobile. Also, English is not my first language! So I will review what I wrote a bit later since it is difficult to see if what I wrote is coherent while on a phone. Do not hesitate if you have any questions!"
]
}
|
[] |
[] |
[
[],
[]
] |
|
2se078
|
Did the British really pretend that carrots derived night vision were the source of their radar-derived intelligence?
|
If so, was the ruse effective? Did the Axis powers have any similar myths about their technologies?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2se078/did_the_british_really_pretend_that_carrots/
|
{
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"text": [
"Yes and no; it wasn't exactly a planned deception, but carrots were mentioned in publicity around John \"Cat's Eyes\" Cunningham, a night fighter pilot, in early 1941. \n\nThe Luftwaffe's switch to night bombing in September 1940 had caused serious problems for the RAF, night defence having a low priority during the prior daylight campaign, negligible successes against night raids precipitated the replacement of Air Chief Marshal Dowding (who had been responsible for much of Fighter Command's success in the Battle of Britain), and fed public perception that German bombers could fly with impunity at night. The ground-based Chain Home radar system faced out from the coast so was unable to track aircraft over land, this being done by the Observer Corps in daylight; Ground Controlled Intercept (GCI) radar capable of operating over land was still in development, a limited number of sets coming into operation in early 1941. Early Airborne Interception (AI) radar was in active service (see e.g. [this photo] (_URL_0_) from the Imperial War Museum of radar equipped Blenheim night fighters from July 1940), but limitations of early sets and the poor performance of the Blenheim (a converted bomber) resulted in few successes.\n\nThe introduction of the Bristol Beaufighter, faster and more heavily armed than the Blenheim, equipped with improved Mk IV AI radar was a significant boost to the RAF's night fighting capability, and Flight Lieutenant John Cunningham of 604 Squadron scored the first kill with one in November 1940. Coupled with the introduction of GCI radar, RAF fighters finally started to become a serious threat to Luftwaffe bombers at night, though gradually; Cunningham received a DFC in January 1941 for destroying two enemy bombers in the course of 25 sorties. To reassure the public, newspapers were allowed to write about Cunningham, and rather than mentioning AI radar he was granted uncanny night vision, hence the \"Cat's Eyes\" nickname that he really didn't like, boosted by eating plenty of carrots.\n\nThe World Carrot Museum (no, [really] (_URL_1_)) has a page on [Carrots in World War Two] (_URL_1_history4.html), including the night vision story (and a recipe for carrot fudge); correspondence from the RAF Museum suggests there was no official attempt by the Air Ministry or RAF to use carrots as a cover for AI radar, but they were happy to play along with the Ministries of Information and Food who built on the Cunningham story to promote the consumption of healthy, unrationed vegetables such as carrots."
]
}
|
[] |
[] |
[
[
"http://www.iwm.org.uk/collections/item/object/205229851",
"http://www.carrotmuseum.co.uk/",
"http://www.carrotmuseum.co.uk/history4.html"
]
] |
|
4gs513
|
why does boiling point of noble gases change as you go down the group?
|
askscience
|
https://www.reddit.com/r/askscience/comments/4gs513/why_does_boiling_point_of_noble_gases_change_as/
|
{
"a_id": [
"d2kg0bs"
],
"score": [
7
],
"text": [
"All atoms, even noble gases like Neon, Argon, etc., experience a type of attractive interaction amongst themselves called \"dispersion forces.\" As a useful oversimplification, the magnitude of this attractive force depends on the number of electrons that the atoms have. Going down a group in the periodic table, you find atoms that have bigger atomic numbers, and therefore more electrons. Hence, larger dispersion forces.\n\nInteratomic forces are the primary determining factor of boiling point, since in order to move an atom from a liquid of itself to a gaseous state, you have to separate it from it's neighbors. In noble gases, dispersion forces are the only real interatomic forces of note. So, the further down the group of noble gases you go, the higher the interatomic attraction due to dispersion forces, and the more energy (i.e. temperature) you need to boil the substance."
]
}
|
[] |
[] |
[
[]
] |
||
2a0sl5
|
why is calling obama a socialist considered an insult? what's so wrong about that type of government anyways?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2a0sl5/eli5_why_is_calling_obama_a_socialist_considered/
|
{
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"text": [
"Because \"socialist\" is a loaded term in American politics, as illustrated by /u/quasiplumber 's response. It inevitably leads to a false equivalence between \"socialist\" policies like progressive tax rates, social spending, and government assistance and \"socialism/communism,\" absence of private property, no free market, government controlled everything, IE Soviet Russia and Communist China.",
"During the Cold War, the \"enemy\" of the United States (as well as most of the wealthy world) were all self-proclaimed socialist nations (The USSR and China being the largest). The word \"socialism\" has come to represent all the things US Americans prefer about their way of life to that of those countries: freedom, democracy and capitalism. So to call someone a socialist is often to associate them with the brutish Communist societies of the Cold War.\n\nObjectively, Obama is not a socialist. Socialism is any social system where the means of production (ie, all the things presently owned by employers like machines and tools as well as land) are \"socially\" rather than privately owned and controlled. Obama is more accurately described as a Social Democrat, someone whose ideal society is quite capitalist but with a government who often intervenes to improve efficiency and fairness.",
"It's only an insult to certain people who think being a socialist is a bad thing. Also, it's just simply not true. Obama is a moderate centrist, and fifty years ago he would have been considered more conservative than Eisenhower.",
"In my experience socialism/communism is kind of mushed into one 'ol put of 'thats bad' by some people in the states. ",
"Obama is not a socialist, so that is a lie. When you tell a lie about someone in order to make them look bad, that is an insult.\n\nThere isn't really anything inherently wrong with socialism, but the USA spent a very long time living in fear of socialist countries during the Cold War, and so many older Americans hear \"socialist\" and think back to the days of seeing \"Russian bread lines\" and \"Joe McCarthy\" and \"the commies are going to nuke us\".\n\nIt scares people and paints him as an Other to be distrusted and feared.",
"Obama in Britain would be right of the centre",
"The election was a bit of a facepalm for actual Socialists because Obama shared virtually nothing ideologically with them. It was basically a purely emotive statement to make and the only real \"proof\" that was ever brought to bear was some half-articulated argument about him engaging in class warfare (with no actual idea what that term meant) and believing in wealth redistribution (spoiler: they believe in it too!) so that automatically means Socialist. \n\nThe equation basically went:\n\nMalformed idea of class war + vague and mis-stated ideas about wealth redistribution + we don't want him to win = Socialist.",
"For some 150 years, there has been an ongoing smear campaign in America against socialism, and now many Americans just automatically associate it it with evil.\n\nBack in the 19th century, socialism became quite popular among people fighting for social justice and decent working conditions and pay. Socialism *almost* caught on as a major political force, there were several socialist political candidates that did well.\n\nBut the robber barons of the time mounted an enormous smear campaign against it, equating it with anarchy, bomb-throwing lunatics, etc.\n\nWhen Stalin shot whoever was standing in front of him and seized control of Russia, that made things a whole lot easier for the smear campaign, because now it was easy to confuse people by conflating Stalinism with socialism (made easier by Russia loudly proclaiming it was socialist. It really wasn't *very* socialist).\n\nAlso in the early 20th century, the government finally got off its ass and started passing health and safety laws, and unions gained significant power in dealing with workplace atrocities, so socialism began to fall out of favor among the general public.\n\nBy the time of the Cold War, the decades of propaganda finally paid off, and socialism acquired the permanent taint of dictatorship and evil some still associate with it today. Indeed, the conservatives managed to shoot down the nascent universal healthcare movement by branding it as \"socialized medicine.\" A B-movie actor named Ronald Reagan even recorded a speech detailing the HORRORS of socialized medicine, and it was released on a record album that got played at a lot of country club luncheons. Decades later, long after the collapse of the Soviet system, when the ACA was being debated, conservatives even trotted out the old term like it was some dusty, moldy, old cardboard Frankenstein statue at a carny funhouse. And people *still* swallowed it.\n\n",
"As to \"what's wrong with Socialism?\"\n\nConsider the following question:\n\nDo individuals serve society or does society serve individuals?\n\nThe United States is built upon the idea that society serves individuals. We believe that life works best when the individuals focus on improving their lives and that society improves as a byproduct. We have relatively low taxes on the rich because we believe the rich will do better things with that money than society (or the government) will. \n\nSocialist countries are built upon the idea that individuals serve society. They (and, in the extreme, Communist countries) believe that life works best when individuals subordinate their needs to the needs of society as a whole. For example, socialist countries have relatively high taxes on the rich because they believe that society (or the government) will do better things with that money than the rich people will.\n\nTo answer your question as to \"what's wrong with Socialism?\" many Americans feel that it answers the above question the wrong way when it says that \"individuals serve society.\""
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[],
[],
[],
[]
] |
||
a01chp
|
How did stories of elves, mates, dwarves, etc. come about throughout the world? Is there any proof that they may have existed at one time?
|
I’m mainly curious of how the tales of the medieval time came about in different parts of the world. From what I have seen, many countries have their own versions of elves, mages, dwarves, dragons, magic and I’m wondering how it spread. I’m curious if there is any evidence that they might have existed in the past or if they were bed time stories told to children (and even then where did they originate from?).
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/a01chp/how_did_stories_of_elves_mates_dwarves_etc_come/
|
{
"a_id": [
"eadtyys"
],
"score": [
13
],
"text": [
"Belief in the supernatural is international. Your question touches on several topics, each of which have generated many books, but it is possible to take this apart carefully and attempt to present a few concise answers.\n\nAlthough many folk stories were/are told to children, and many more were told as fiction (usually called folktales by folklorists) for adults, this doesn't preclude many of the topics of these stories from also being matters of belief and the focus of stories usually told to be believed (typically referred to as legends). Again, internationally, stories told as fiction and those told to be believed both include supernatural entities - as well as normal men, women, and children.\n\nThere is no reason to assume that any supernatural entity - whether humanoid or animal in form - is based on anything that existed in the past. Many have constructed theories along these lines, and while they are often seductive, these scenarios cannot be proven, are often easy to demonstrate as false, and/or are simply not needed to understand folk belief. For example, one often sees the idea put forward that dinosaur skeletons are the basis of beliefs in dragons: while fossils may have helped put wind in the sail of belief, there is no reason to conclude that this was the origin of the tradition. The result is a rather unsatisfying answer to your question about the origin of belief in the supernatural: it is something we simply cannot really know. Again, beliefs are international and historical cultures burst onto the scene with written records exhibiting beliefs and tradition in full blossom, so it is clear that these sorts of beliefs - and related stories - are part of a prehistoric legacy that may go back tens of thousands if not hundreds of thousands of years to a time we can only dimly imagine.\n\nGiven that last point, it would be easy to imagine that many supernatural beings are linked by some common, ancestral belief system. It may be possible that this might be the case, but again it would be difficult to prove, and more often it seems less likely to be the case. Supernatural beings that seem similar - ghosts, dragons, elves - seem as though they have international counterparts, but upon closer inspections, dramatic differences suggest that a common ancestor is less likely. The ground-crawling, Northern European worm/dragon (which later took to the sky with wings) was a nemesis that is very different from the often beneficial Asian supernatural entity, which only as a matter of linguistic limits is described with the same English term. Belief in people surviving death are international, but a walking corpse is different from an ethereal spiritual manifestation. And while European elves steal babies and replace them with changelings and the Northern Paiute paúngaa’a does much of the same, the European stories tell of the return of the baby by a community of elves that merely wanted the human as an addition to their society, while the paúngaa’a has eaten the baby and seeks the opportunity to chew into the mother's breast, only to slither back into the water from which it came. These are all so different, it is less likely that they descend from a common ancestor."
]
}
|
[] |
[] |
[
[]
] |
|
1xj0z1
|
what is the onion magazine?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1xj0z1/eli5_what_is_the_onion_magazine/
|
{
"a_id": [
"cfbr5r2"
],
"score": [
3
],
"text": [
"The Onion is a humor and parody newspaper that makes fun of political, social and economic events in the world through parody and exaggeration. "
]
}
|
[] |
[] |
[
[]
] |
||
6jc1qa
|
so i bought 'new' listerine with no alcohol. what's left in it that kills germs? do i need the alcohol?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6jc1qa/eli5_so_i_bought_new_listerine_with_no_alcohol/
|
{
"a_id": [
"djd4maq"
],
"score": [
6
],
"text": [
"Alcohol isn't actually the ingredient used to kill mouth germs, its primary purpose is to keep the actual active ingredients in solution. Alcohol free Listerine, according to their site, uses essential oils with antibacterial and anti-fungal properties. I'm unsure what ingredient in the Zero Alcohol formula keeps the oils in solution"
]
}
|
[] |
[] |
[
[]
] |
||
dmyn5t
|
How good is the sense of smell in insects such as flies?
|
askscience
|
https://www.reddit.com/r/askscience/comments/dmyn5t/how_good_is_the_sense_of_smell_in_insects_such_as/
|
{
"a_id": [
"f58lfb7"
],
"score": [
6
],
"text": [
"Well, they don't have noses or olfactory organs, just chemoreceptors on their antennae. How well they detect airborn compounds depends on the type of insect, and the specificity with which they detect certain molecules but potentially not others. Certain insects will be very good at detecting organic compounds released from the specific food source they typically seek, but may not be able to 'smell' other things at all."
]
}
|
[] |
[] |
[
[]
] |
||
13qo6b
|
grover norquist is just some guy. why do politicians behave as if a pledge to him is sacred?
|
One would think that their allegiance would be to their country, not some random guy.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/13qo6b/grover_norquist_is_just_some_guy_why_do/
|
{
"a_id": [
"c769t0d"
],
"score": [
2
],
"text": [
"Norquist is an incredibly influential \"just some guy,\" and his tax pledge is technically a pledge to the *voters* not to raise total taxes, not to Grover."
]
}
|
[] |
[] |
[
[]
] |
|
6xgixf
|
why was cavalry so effective against infantry without spears?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6xgixf/eli5_why_was_cavalry_so_effective_against/
|
{
"a_id": [
"dmfqk2l",
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2
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"text": [
"I think this is pretty self a explanatory, but I'll do my best. As far as I know, earlier armies were focused around phalanxes or turtle formations, think Greeks or romans, pretty much meaning they'd make walls out of living bodies and see which side broke first. Early cavalry was more mobile, but didn't have stirrups, which didn't allow them the advantages of heavy cavalry in the middle ages. Now imagine mobility with a more powerful punch. Your army can out-maneuver your enemy, and when you meet on the field of battle, you have more control of location, which is a serious tactical advantage. I'm sure seeing a herd of horses with bad guys on top of them charging down at you didn't help with morale, either.",
"Well first of all, the depiction of cavalry charge in movie is usually incorrect. Most of the way they show it in movie wouldn't work. An infantry man have the advantage over a cavalry man in a static fight.\n\nCavalry was pretty much never the main part of an army. It usually was just a small portion of it, in a specialised role.\n\nI'll simplify it a lot, but you get mainly two type of cavalry with different role and capability. Light cavalry is the oldest. It wasn't that powerful, but was really good at several things. The main advantage was their speed. So they used that to focus manpower in weak point, reach enemy archers, flank the infantry and root the fleeing enemy. They also serve as scout. They were rarely used as battle cavalry and when they did it was usually as harassing force, like launching javelin or using spear as they pass the flank of the enemy. \n\nHeavy Cavalry war not really around until later in history. Cataphract was an early version of Heavy Cavalry and like you can see, they are more armoured than the charging calvalry we usually see in movie. The name Cataphract mean completely enclosed.\n_URL_0_\n\nTheir strong horse, made heavy cavalry able to have more armour, which protect them very well against attack from infantry and the weight of all that make them are to drop drag out of their horse. That said, they are still vulnerable against infantry in a static combat. That's why in a cavalry charge, they usually focus on the side of an enemy formation so that they can continue the charge away from the enemy and not end up in the middle of infantry man in a static fight.\n\nThe advantage is the shock of a charge. With the weight of the horse and the armour, a Heavy cavalry man hitting an infantryman, even if they don't cut or impale them, will most likely kill or severely injury them. This also cause chaos in the enemy formation, while make them vulnerable to other type of attack. For example, the Persian used horse archer against the Roman infantry to force them into a tortoise formation. But that formation is vulnerable to an heavy cavalry charge because they don't move. A charge will break the formation, leaving them vulnerable to an infantry or archer attack, while the cavalry get out of the way and prepare for another charge."
]
}
|
[] |
[] |
[
[],
[
"https://upload.wikimedia.org/wikipedia/commons/4/4a/Ancient_Sasanid_Cataphract_Uther_Oxford_2003_06_2%281%29.jpg"
]
] |
||
6f3wvd
|
what does it mean for an actor to be executive producer on a tv show?
|
What kind of direction do they give? How does this affect the production?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6f3wvd/eli5_what_does_it_mean_for_an_actor_to_be/
|
{
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"dif8fiz",
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16,
48,
19
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"text": [
"I work in the film industry and am an 'executive producer' on smaller productions. Simply that means I work with the client stakeholder to hire any and all staff (either directly or indirectly) for a production. I also handle budgeting and empower a director to execute the project vision, etc.\n\nIn professional productions, there is a consistent standard which you can read about here. \n\n_URL_0_\n\nWhen things are altered beyond this 'standard set of roles' someone can handle multiple roles such as acting and putting forth the financials to make the production and may gain multiple credits in IMDB or as the credits role... \n\nSummary: there are many ways to skin a cat ;)",
"Sometimes nothing. For a popular show, when the lead actor(s) renegotiate their contracts, they may ask for an Executive Producer credit as a sign of their status, or because it gives them a small portion of the profits. \n\nSometimes they may actually have a larger role in determining the direction of the show and the writing, or may even choose to direct an episode - see Bryan Cranston in Breaking Bad.\n\nSometimes they may have lent their name and status to helping a show get made, but have little to do with it afterwards. See Martin Scorsese and Boardwalk Empire - he directed the pilot and was involved in developing the show, but didn't have much of a hands on role after that.",
"Executive producers make much more money on the back end. For a TV show, giving an actor an exec producer credit boosts their earnings considerably—especially in the residuals. In Seinfeld, for example, Jason Alexander admitted that the reason he didn't continue with the series is because there was no upside for him. Whereas, as an Executive Producer, Jerry Seinfeld stood to make billions in syndication.\n\nBryan Cranston's Executive Producer credit in Breaking Bad probably increases his earnings in syndication by a factor of 10 (if not 100)."
]
}
|
[] |
[] |
[
[
"https://en.m.wikipedia.org/wiki/Film_crew"
],
[],
[]
] |
|
22a9sb
|
In feudal times did the nobility of europe have a distinct ethnicity that seperated them from the rest of the population?
|
Because the nobility of europe would mix with the nobility of all over europe did they have ethnic features that were generraly different from the rest of the country's population?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/22a9sb/in_feudal_times_did_the_nobility_of_europe_have_a/
|
{
"a_id": [
"cgl1k0k"
],
"score": [
9
],
"text": [
"In some instances there could be. For instance; after the Normans invaded England, the nobility was Nordic (Norman) whereas most of the rest of the population was not. "
]
}
|
[] |
[] |
[
[]
] |
|
11q5f8
|
Is there a "genetic peak"of attractiveness in humans?
|
askscience
|
http://www.reddit.com/r/askscience/comments/11q5f8/is_there_a_genetic_peakof_attractiveness_in_humans/
|
{
"a_id": [
"c6oojp0",
"c6oqts4"
],
"score": [
2,
2
],
"text": [
"There is no molecular definition of attractiveness, so I'm not sure what kind of answer you're looking for here.",
"I don't think you'll find a real scientific answer to this. I might be able to give you something that might be of interest to you. I read about a researcher studying serial killers (which tend to be generally ugly fellows) who decided to overlay a bunch of their mug shots hoping that their combined pictures would produce a \"face of evil.\" Instead what they got was an exceedingly attractive male portrait. \n\nIt turns out that this happens when you overlay any set of people no matter how ugly. If you combine pictures of multiple people into one portrait all the facial abnormalities and uniqueness-es melt away and the shared characteristics get emphasized creating something generally accepted as beautiful [like so](_URL_0_). You might be tempted to say that the human consensus for what is attractive is an \"average\" person."
]
}
|
[] |
[] |
[
[],
[
"http://i.imgur.com/ZzGrU.jpg"
]
] |
||
9gwxcj
|
why are we certain there wasn't a technological civilization before humans here on earth?
|
It took only some 10000 years from being cavemen to going to space. It is a tiny interval in evоlutiоnal and geological scale. How can we be certain that say 30000 or 50000 years ago there wasn't another technological civilization here on earth?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9gwxcj/eli5_why_are_we_certain_there_wasnt_a/
|
{
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"text": [
"We can't. Just like we can't be certain the universe wasn't created by an invisible purple teapot orbiting Jupiter. \n\nWe *can* be certain they didn't use large amounts of plastics, as those show up clearly in fossil records. They also didn't use any carbon or soot producing technology on an industrial scale, didn't launch any geostationary satellites, leaded gasoline, rare earth metals, gold, lithium, or any of the elements we use for advanced technology. \n\nAt that point, the question is how you define technological civilizations. Personally I tend to think *widespread technology* is a requirement and we know no one had that before us. ",
"It's not that scientists are not certain about this.\n\nIt's just that there is no known existing data or phenomena that point to this being likely, and there is no evidence pointing, with any certainty, that there was such a civilization.\n\nAs to your point about cavemen to space, Moore's law is an interesting read on this, but basically, science builds upon science. 10,000 years ago, short life spans, struggle just to eat and not get killed.\n\nThings that multiply the ability to develop science gradually entered in, such as increasing global travel, ideas being recorded and taught to others, more and more leisure and longer lives resulting in more and more ability to pursue advances.\n\nStarting in the 90's, we got the internet, enabling us to share data, instantly, world-wide. \"Google it\" is now a verb phrase we wouldn't have dreamed of in 1975. Or I should say, thank goodness for the few brilliant people who probably DID dream of it then.\n\nSo the more technology we have \"in the bank\", the more we can use it to build upon and advance farther and farther.\n\nWhat will the world be like in 100 years?\n\nBut what we don't know if what it looked like 30,000 to 50,000 years ago, in terms of any civilization. Just no evidence for it.",
"On the scale of *thousands* of years you'd have vast archeological/radiological/ice core/atmospheric evidence, of which there is none.\n\nWe can't truly be certain for vast timescales of hundreds of millions of years since that fossil record is so sparse, but the complete absence of any evidence makes it highly unlikely. For a species to so thoroughly dominate the planet like we have and then vanish without leaving a single fossilized car tire or bottlecap is a real long shot.",
"We aren't certain. However, consider the massive global changes humans have made in those '10,000 years.' We have significantly altered the atmosphere, the crust. We have erased major mineral deposits and created new entirely unnatural deposits, signs of both of which will persist for millions, if not billions, of years. \n\nIt is quite possible that if we went extinct tomorrow, we'd be detectable for the entire foreseeable future of the Earth in *some* form, and not necessarily subtly either. \n\nThere's no strong reason to believe an equally capable species in the past would not likewise be so observable. "
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
|
64786i
|
What do historians think of Benedict Anderson's Imagined Communities?
|
I am a geography major specialising in Southeast Asia, and was quite drawn to Anderson's "last wave" theorisation for the development of Southeast Asian nation states. Within my university which specialises in Southeast Asia, Imagined Communities is the point from which any understanding of nationalism or political geography is orientated towards.
What do historians think about that book - from other similar threads I get the feeling that any academics not specialising in history (of the top of my head:Jared Diamond, Chomsky, David Harvey) often leave giant holes in their theories. So I am curious: What do historians think of Benedict Anderson's Imagined Communities?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/64786i/what_do_historians_think_of_benedict_andersons/
|
{
"a_id": [
"dfzwey1"
],
"score": [
2
],
"text": [
"Hi there -- this is a question that's come up here a few times before. Not discouraging any further discussion on it, but these older threads may be of interest to you: \n\n_URL_0_\n\n_URL_1_\n\n_URL_2_\n\n_URL_3_"
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/5noyoq/how_can_i_explain_the_constructed_nature_of/",
"https://www.reddit.com/r/AskHistorians/comments/4nw1xa/what_do_people_mean_when_they_say_that/",
"https://www.reddit.com/r/AskHistorians/comments/1kohp2/why_is_nationalism_considered_a_modern_concept/",
"https://www.reddit.com/r/AskHistorians/comments/15xw3h/when_did_nationalism_begin_and_where_did_it_come/"
]
] |
|
5b289m
|
gradient descent algorithm
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5b289m/eli5_gradient_descent_algorithm/
|
{
"a_id": [
"d9l7fgm",
"d9l8s5t"
],
"score": [
7,
2
],
"text": [
"Imagine you're stranded in a mountainous area, and you're blindfolded. \nYou'll be rescued if you reach the lowest point in a valley. \nYour only knowledge of your immediate surroundings comes from placing your foot one step away from yourself, and estimating which direction takes you the furthest downward. \nThat's it basically, and it's quite accurate for a simple GD problem in 3 dimensions. It can be further complicated if there are multiple valleys, and real problems will usually have more dimensions (so just replace \"checking the direction that goes downward the most\" with \"taking a derivative and choosing the direction that minimizes it\". \nI'm a bit rusty on this topic but I think that's accurate enough to get the idea. ",
"start at point a calculate the gradient of your function del F(a) , calculate point b by: \n \nb=a - y del F(a) \n \nwhere y is a small increment \n \niterate and track the value of the function F until you reach a mimimum"
]
}
|
[] |
[] |
[
[],
[]
] |
||
6dfh7c
|
Who lived in Britain before the Britons?
|
[deleted]
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/6dfh7c/who_lived_in_britain_before_the_britons/
|
{
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"Well, Britain has seen activity from Palaeolithic times and you can see an example of the continuity at work here in Norman Davies' *The Isles*, which speaks of continuity in DNA from a Stone Age body to a living member of the town where the body was found.\n\nIn among this continuity however there is also considerable migration, a two-way stream. Hunter-gatherers in the Mesolithic would have come up from what was a refugia in Southwest France and Northern Iberia; farmers appear to have come from Brittany and the Low Countries via the Middle East, the Beaker people originated on the Continent and made there way here, and now DNA hints at a large-scale population replacement in the Bronze Age. Finally, Celtic expansion into the Isles from their homeland in modern Austria preceded the Romans.\n\nSo the Britons (and the Irish) are a melange of different peoples, with different origins. I'd suggest reading *The Isles* along with *Britain Begins* by Barry Cunliffe.",
"As a follow up question, do the Irish descend from the Scythians or is it more folklore than fact?\n \nI believed the early inhabitants of Ireland were Celtic people that came from the north of the Iberian peninsula and, before that, from the area currently belonging to Austria, where the core of the Celtic culture began. However after reading [a bit from this article](_URL_0_) it seems that the Irish are related to the Scythians, who lived more or less where Ukraine is now.\nCould a historian clarify this matter?",
"I’d like to correct some misconceptions in the question, and then expand a bit on what u/tbickle76 wrote. \n\nCaledonians were indigenous peoples living in what is now Scotland. They were not of Roman origin. Tacitus records them fighting against, and being slaughtered by, the Roman general Agricola in 83 CE, after which they seem to have been absorbed by the Picts. The Scots, however, originated from neither Caledonians nor Picts, but rather from the Scotti, immigrants / invaders from Ireland. \n\nGermania, from the Roman perspective, was the region of Europe east of the Rhine, which was *outside* the Roman Empire. During the time when Roman power was in decline, diverse groups of germanic speaking people migrated / invaded throughout the Empire, but during earlier times of Roman expansion, the character, culture, and influence of the Roman west was not Germanic. The Germanic origin of the English language is a result of post-Roman Anglo-Saxon migrations. \n\nAs tbickie76 pointed out, the British genome is and has been the result of both continuity and migration going back long before anything that can be called history, but I’m not sure genetics and ethnicity are the most useful criteria for identifying “who” an ancient people are at a given time and place, specifically here the British on the eve of Roman conquest. At the time of Roman expansion into northern and western Europe, the people living in this region can generally be called Celtic, a term which refers to a broad group of languages as well as a continuum of cultures and religious practices across a region that included modern France and Britain. The names of many British rivers are of celtic origin (Avon, Mersey, Severn, Thames), as is that of the Isle of Wight and the city of Leeds. \n[This very detailed map](_URL_1_) (edit: also [here](_URL_0_)) shows the extent of Celtic and Germanic speaking tribes throughout Europe in 52 BC.\n\nThe Romans recognized the ties between those mainlanders they called Gauls and the tribal people living on the mysterious island they called Britannia. Gauls living in northwestern Europe and Britons living in the south of the island traded with each other across the channel and lived in societies with similar cultural patterns and religious practices. They lived in small settlements that the Romans called “Oppida”, were dominated by warrior elites alongside a priestly class of Druids, and constructed hilltop fortresses for defense. Julius Caesar made two rather quixotic stabs at an invasion of Britain in 55 and 54 BC, Rome’s first military contact with the island, ostensibly as retribution against British tribes who had aided the mainlanders in a recent revolt against Roman rule.\n\nSources:\n\nAsa Briggs \"A social History of England\"\n\nAdrian Goldsworthy \"Caesar: Life of a Collossus\"\n\nSimon Schama \"A History of Britain\"",
"I think there's a fundamental misunderstanding in this question about how ethnicity and genetics works. While your question perhaps portrays ethnic groups like a simple video game mechanic where one solid group comes to replace another, the reality is far more complex. Labels like 'Roman' 'Caledonian' 'Celt' etc.. don't so much describe unified 'races' of competing people but rather complex and overlapping cultural identities.\n\n It's not as if one group was living in Britian only to be wiped out and replaced by another, but rather people who's genetic history in Britian going back before recorded history, mixed with immigrants (to this day) who gradually adopted different cultural ideas either through trade or conquest. \n\nIt's perfectly possible that a linear family going though the generations would at one time consider themselves to be a certain Celtic tribe, then after the Roman conquest mix that identity with a broader Roman one, then centuries later start to identify with a Germanic Anglo Saxon identity as it became dominant. "
]
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"https://en.wikipedia.org/wiki/Scythians#Descent_claims"
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"http://www.historyfiles.co.uk/FeaturesEurope/Barbarian_Map52BC_max.htm",
"http://www.historyfiles.co.uk/images/Europe/Barbarians/Map52BC_Gaul01_max.jpg"
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2epd0f
|
If photons are massless, could an infinite amount of them fit into an infinitely small space?
|
askscience
|
http://www.reddit.com/r/askscience/comments/2epd0f/if_photons_are_massless_could_an_infinite_amount/
|
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"Someone correct me if I'm wrong. But doesn't that Pauli Exclusion Principle say that, in fact, you could fit as many photons into as small of a space as you want and keep adding them up until their collective energy starts becoming a GR-type problem?",
"You're going to have a hard time really calling them photons when you cram them into that small space. Let's look at limiting behavior.\n\nIn a small box, you can put an extremely large number of photons with wavelengths that fit inside that box. At some point, your energy density rises to the point where talking about the photons and the box is no longer meaningful because gravity has stepped in and you've made a black hole. But ignoring that, as others have said, Bose-Einstein statistics allow any number of photons to occupy the same state (that state, in this case, being \"ground state resonance in our box\" [that is, the longest wavelength and thus lowest frequency/energy that will fit a half-integer number of waves inside the space, to obey the boundary conditions that the photons stop at the edge of the box and aren't outside it. The box is our universe]).\n\nIf we shrink the box length down though, keeping the photons localized to the increasingly small volume is... problematic. Not really from an engineering perspective (though absolutely that as well) but also because we're increasing the energy of each photon as we shrink the wavelength, and these energetic photons are hard to spatially confine thanks to the uncertainty principle. \n\nYou can't really say \"I have ten thousand photons with precisely this energy sitting at this point\". In fact, once you get \"precisely this energy\" the only way to physically realize that is with universe-spanning waves, such that the uncertainty in the position and momentum (and thus energy) of the particle remains greater than a certain number (h? hbar over two? It's been a while, and the exact value is secondary to the main point).\n\nWe never really make photons with such perfect energies though (since, y'know, universe-spanning); our equipment also falls under the control of uncertainty, and so a red laser which produces light with a wavelength of 650 nm ACTUALLY makes a small spread around that value, which lets us localize the photons/laser beam.\n\ntl;dr Uncertainty limits how small a space you can cram them into if you want to be clear about what kinds of photons you have, gravity breaks up the party past a certain energy density and cordons off a section of spacetime larger than what you want and just keeps the light in there.",
"There are three very practical problems that would prevent you from doing this (nevermind singularities, general relativity, etc):\n\n1. Electromagnetic radiation has a wavelength, and cannot occupy a container (in steady-state) that is smaller than one wavelength. The relationship between a photons wavelength and the size of the container is discussed in [this](_URL_0_) Wikipedia article about a practical instrument that uses this relationship.\n\n2. The container will absorb the photons. This is also discussed in the [same article](_URL_0_) when they discuss the \"finesse\" of a cavity. Of course you could get around this constraint by using a superconducting container (which is a trick they use in particle accelerators), or by constantly adding photons back in.\n\n3. Photons exert [radiation pressure](_URL_2_), so an infinite number of photons would exert an infinite amount of pressure on the container, thereby destroying it. This is a concern for particle accelerators using superconducting containers, as the radiation pressure will cause them to be deformed (see [this](_URL_1_), for example, section 2.2)\n\nHope that helps!",
"To kind of correct from some of the very poor explanations below:\n\n1) photons are massless, but this has nothing to do with how you can pack them. \n\n2) Photons are Bosons, and hence not subject to Fermi-Dirac Statistics, and thus, not subject to the Pauli-Exclusion principle\n\n2b) Corrollary: in fact, part of the interesting thing about Bose statistics is that bosons *prefer* to be clumped together, almost acting as \"one\" particle. These are called \"Bose-Einstein Condensates.\" We made a Bose-Einstein Condensate (BEC) of photons in 2010, in fact.:_URL_0_ This is as close to your original question as an answer is likely to get.\n\n3) \"infinitely small space\" is a problem. Due to the Heisenberg uncertainty principle, the more tightly confined in space particles are, the less precisely known is their momentum. So if photons were in a very very small box, they'd have such a wide range in momenta that they'd never condense into a BEC. However, a BEC of photons may exist within a very small, but not infinitesimally small, space.\n\n4) also, I feel it's worth pointing out: any system of photons in which the photons are not precisely moving in the same direction has a mass, even though all the photons are themselves massless. I actually don't know what it means for a BEC of photons, because since they're all in the same quantum state, they probably all have the same momentum vector, and thus would remain massless still, but I'm not sufficiently strong in the area to say for sure.",
"Not to be a pedant: but massless is not the same as having no volume.\n\nAlthough I believe no fundamental particles actually have volume, some just repel each other because of various forces like electromagnetism or the strong nuclear force. Particle physicists please correct me if I'm wrong. ",
"The fundamental limit you cannot pass is uncertainty.\n_URL_0_\nOnly with infinite momentum spread would you have a singular position of the photon. This means a photon of infinite bandwidth and therefore energy.\n\nCan that exist? We don't know if there is an upper limit to photon energy so we are unsure.\n\nAssuming you get around the problem of this photon with infinite energy the there is another issue.\n\nIs space nonlinear? If it is then multiple photons in the same space of that power will interact with each other indirectly by changing the impedance of the free space they occupy. Such effects generally work to separate photons. Again this is a question that has not been answered."
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"http://tesla.desy.de/new_pages/TDR_CD/PartII/chapter02/references/Bousson.pdf",
"https://en.wikipedia.org/wiki/Radiation_pressure"
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"http://www.nature.com/nature/journal/v468/n7323/full/nature09567.html"
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2h87ob
|
why did the us government have no trouble prosecuting microsoft under antitrust law but doesn't consider the comcast/twc merger to be a similar antitrust violation?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2h87ob/eli5_why_did_the_us_government_have_no_trouble/
|
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"The DOJ has not yet ruled on whether or not the merger will be a violation of antitrust rules.\n\nNow, once they have, and if they say it isn't, then you have a really good question. But at this point, it's premature.",
"Comcast and Time Warner don't compete with each other in many ways, their cable systems are all franchised, so each is its own little monopoly. With a few exceptions, it's not illegal to get bigger (even when that means adding more local monopolies to a group of other local monopolies). \n\nMicrosoft was prosecuted for trying to use its ownership of Windows to make it impossible for Netscape to become the dominant browser. That's against the law. ",
"The US Government *did* have trouble prosecuting Microsoft. They investigated repeatedly throughout the 90's, but they only got a slap on the wrist by the European Union and nothing more than a finger waving by the US DoJ... if anti-trust laws still had any teeth they would have been split into a couple companies (OS, Office, etc).\n\nThe issue with Comcast/TWC is that they're effectively operating as a cartel (by not competing with each other now), and it's a discussion about how much future competition the merger actually prevents.\n\nWe should be discussing nationalizing broadband infrastructure, but I digress.",
"People seem to think antitrust means anti-monopoly. It doesn't.\n\nIt means that a business (or group of businesses) can't 'conspire' to make an unfair market for the consumers.\n\nComcast isn't actively conspiring with anyone (business wise). They have fallen into a position of having a natural monopoly. No other competitors. (This is more the government's fault than other telecoms) You can't hold a company at fault if they don't have any competitors in the areas they are active. The same with TWC.\n\nBut let's use the old Ma Bell example. Ma Bell set it up to where no one else could compete in the market (not allowed) as compared to no one else chose to compete in the market (didn't want to). That's why the government stepped and broke them up.\n\nBut let's shift gears a little. Take Coke & Pepsi. If a couple executives from each company got together and decided that a 12oz can needed to cost $2.00. That's a conspiracy to create an unfair market. That's what anti-trust is about. But they don't do that, they let the market determine how much a can costs. Sure they set MSRP, and they have the same MSRP, but they do it independently.\n\nThe same goes with these cable companies. \n\nNow when it comes to mergers. The SEC does review these big organizations and look for conflicts of interest. They try to head these things off at the pass. But when it really boils down to it, you have to prove the company is working outside normal market forces (there is an actual violation).",
"Microsoft didn't give as much money to politicians as Comcast did.",
"You could ask why they haven't broken up AT & T into baby bells again. The truth is that Corporations keep lobbying the definition of a Monopoly. They increase market share by corrupting our politicians and laws. They will keep going until 99% isn't considered a Monopoly.",
"Because the US Government anti-trust law isn't about fair competition. It's about getting companies with a lot of money and influence to play ball with what ever government policy is and not to go against the government. \n\n_URL_0_",
"Antitrust lawyer here.\n\nFor one, we're talking about different antitrust issues. Broadly speaking, the antitrust laws prohibit (1) concerted action that harms competition, like price fixing cartels; (2) unilateral action by a monopolist that harms competition; and (3) mergers and acquisitions that significantly diminish competition.\n\nMicrosoft was alleged to have used its position as a monopolist to undermine competition. That's (2) above. Typically, monopolization entails an element of foulplay. Achieving or maintaining a monopoly through normal, reasonable business practices is not illegal.\n\nComcast and TWC are proposing to merge. That's (3) above. When evaluating a merger, the DOJ looks at whether the companies directly compete in any markets, and whether the merger is likely to reduce competition in those markets.\n\nComcast and TWC claim that they do not directly compete. That's true, but there's more to the story. Comcast and TWC will point out that cable systems are \"natural monopolies\" -- it costs a lot to lay cable, and where one company has already laid cable in a given area, it enjoys a huge cost advantage over other would-be competitors, who would have to lay their own cable to compete.\n\nBut on the other hand, Comcast and its rivals have also done some dubious stuff in the past that has led to the current competitive landscape. For example, Comcast, TWC, and others have engaged in a number of anticompetitive deals, such as geographic market allocation and customer swapping, to create large regional monopolies. These deals themselves arguably violate the antitrust laws -- see (1) above -- and indeed are the subject of ongoing litigation. But unfortunately, the DOJ most likely would not take this background into account when evaluating the likely effect of the merger on competition.\n\nSo when Comcast and TWC say that the merger will not reduce competition because they do not currently compete, that is in part due to the fact that they have already *agreed not to compete*. It's like two members of a price fixing cartel saying that merging would not reduce competition because, hey, they aren't competing anyway.\n\nWe don't know yet whether the DOJ will challenge the merger. The Obama DOJ has been decent in this area; they challenged the AT & T/T-Mobile merger and US Air/American Airlines merger. But neither of those cases played out -- the FCC killed AT & T/T-Mobile, and the DOJ caved once politicians began pressuring the agency to let US Air/American Airlines go through.\n\nGiven that Comcast is so well connected in Washington, and in light of the potential difficulties in establishing that the merger will actually reduce competition, I expect that the DOJ will approve the Comcast/TWC merger, subject to certain concessions.\n\nPolitics is a core issue when it comes to antitrust enforcement. In fact, I don't think the Obama DOJ would sue Microsoft today. Clinton's DOJ was a bit more aggressive in this area.\n\nHope this helps.",
"Two reasons: tech companies didn't bother much with lobbyists until recently and thus lacked political influence, and also the fact that regulatory agencies are hopelessly corrupt tools of partisan politics. \n\ntl;dr: follow the money. ",
"Because $$$, that's why. \n\nDon't bite the hand that feeds your fat corrupt pockets.",
"Because Comcast knows how to spend money in Washington, while Microsoft thought they could be the new king on the hill without playing ball. ",
"I'd also like to know why Microsoft got into loads of trouble for bundling IE with Windows, eventually (at least in the EU) being forced to present you with a choice of browser to download on a new install of Windows but Apple are allowed to bundle Safari with OSX without even a slap on the wrist.",
"My dad was one of the anti-trust attorneys who represented the government in the Microsoft case, and is now representing the US government in the Comcast/TWC merger so I have some intimate knowledge of both cases. In the case of Time Warner/TWC, they can argue that since they don't compete with each other in a lot of markets, they aren't consolidating their market shares. It's a flimsy argument, but they have near-infinite legal resources and the government doesn't, so the reality is, if the government tries to stop the merger from happening, they will fail. Same as Microsoft, the outcome was very favorable for Microsoft because they had the DoJ enormously out-lawyered. What they're trying to do instead, is negotiate terms of the merger that will be most favorable to the consumer. It's exactly the same thing as the American Airlines/US Airways merger. They will have to agree to not raise their prices more than X% per year for Y years in markets where they would effectively have a monopoly, and other consumer-friendly regulations. ",
"Personally having worked in both industries, it has more to do with political winds and people in the Government picking winners and losers than the facts.",
"To prosecute under antitrust, there needs to be evidence of abuse (let's say inflated pricing or inferior product offering based on the power the entity has in a market or region). Since twc or comcast tend to deliver 'about' the same products and pricing as most other service providers in other areas, there is no easily provable abuse going on. \n\nBad customer support isn't really abuse, though it can open them up to civil lawsuits. ",
"Comcast spends a fortune on lobbying. Microsoft didn't. (They spend a lot more now. They learned.)",
"For many years MSFT never spread the wealth with campaign donations like good corporate citizens should:\n\nIn 1991-1992, $61K was given.\nIn 2011-2012, $2.3M was given.\n\n[Source](_URL_0_)",
"microsoft bribed the wrong people/bribed in insufficient amounts",
"The antitrust suit was mostly about Microsoft giving a free copy of a web browser with the OS - after the antitrust suit Microsoft still gave a free copy of the web browser with the OS. The only major change for Microsoft was their participation in political spending. Once they started showering politicians and their favored charities with money the feds backed off.\n\nComcast has always showered the political class with money which is why the feds mostly leave them alone.",
"While /u/Ah_Q's answer is very good, the bottom line is this: corruption.\n\nThe spirit of antitrust law is to protect consumer choice, and improve consumer quality of life through that choice (quality of life meaning better goods & services at lower prices - really, what the foundation of capitalism and our entire economic paradigm is built on).\n\nA merger between Comcast/TWC does not benefit consumers, at all. There is no case to be made that it does, because it doesn't. Thus there is only one way in which the merger will be approved, and that's through corrupted political channels*, including outright bribery as defined by the average, every day normal people that our government is supposed to serve.\n\nLawyers and politicians can fuzz the language and legal technicality all they want, but the end result is the same: citizens get fucked.\n\n*Or perhaps our government is beyond corruption at this stage. Corruption implies a government body favoring special interests in exchange for favors. But perhaps our government is favoring special interests, period. No favors involved, they simply don't even care about their purpose as lawmakers anymore. They aren't standing on \"our\" side of the fence and taking bribes through the links, they are standing squarely on the other side of the fence now with their backs turned to us...\n\nBribing a congressman now is more akin to just preaching to the choir, making water wet, or attempting to kill that which has no life...",
"For perspective on the Comcast/Time Warner merger, the FTC opposed the merger of Whole Foods Market and Wild Oats on anti-competitive grounds, because, ya know, you can't buy groceries anywhere but Whole Foods or something.\n\n_URL_0_\n\nSo, it will be interesting to see if the same agency that thinks Whole Foods owns a food monopoly, doesn't see any issues with this merger.",
"I read the Microsoft plea deal - It said in essence: \"We admit no wrongdoing, and anyway, we promise we'll ever do it again.\"\n\n",
"Because Microsoft wasn't spending millions on lobbying. Now they are. Tech companies got the message. Butter the bread or get fucked. ",
"Because Microsoft didn't OWN the board at FCC. Prior to working at the FCC, Wheeler worked as a venture capitalist and lobbyist for the cable and wireless industry. Another one of them is a former Verizon lawyer. ",
"Here is the real skinny-\n\nComcast owns NBC-Universal which owns MSNBC and has a ton of lobbyist working on their behalf. MSNBC has been totting the administrations water for a long time. This gives Comcast tremendous leverage. Though everyone with half a brain knows that this is a bad deal for the consumer and will lessen competition, it is proceeding because Comcast has paid off the administration with it support and MSNBC's bias coverage.\n\nAs for them dividing up the country geographically that is illegal (collusion) in itself. This deal will make any law suits concerning that that go away and head off any future law suits.\n\nAs for Microsoft, Bill Gates was minding his own business with zero lobbyist and not really interested in politics. Bill Clinton brought the action antitrust to wake Gates up and get some of that dotcom bubble money in the Democratic coffers. Gates hired the necessary Democrat flacks for lobbyist and gave a big donation to the DNC and the whole thing went away.\n\nI believe Gates did limit competition and should have been broken up. The operating system and the application system should have been made into two different companies. There were a bunch of great companies. Lotus and WordPerfect were far better than the MS products (Word is still the WP from hell). When MS and intel moved to 32 bits, Word and Excel immediately had 32 bit software. Lotus and WordPefect were frozen out for nine months or a year. Microsoft leveraged Windows95 into making their software the office standard. MS office is around $600. Word Perfect Office is $69.00.",
"Cable company's buying each other out is not going to affect competition because most cities have only one cable company anyway. Time Warner and Comcast use the same software platform so people really will not see a difference. Both have shitty call centers though but that's with any large corporation.",
"\"Antitrust law\" isn't just a penalty/prevention against companies that are too big. Being too big of a company isn't a crime.\n\nMicrosoft got in trouble for using their dominance in one area (operating system) to give themselves an unfair advantage in another area (web browser). It was anticompetitive; other companies couldn't possibly do well even if they were the best choice.",
"Lobbying. Its important to remember that although America claims to be democratic and capitalist, its Congress is for sale, and the Government provides socialist like services to the super rich billionaire class. I say services as they through lobbyists pay congresspeople to act on their behalf in that manner. Democracy has become a punishment.",
"The Comcast/TWC monopoly costs consumers money. The Microsoft monopoly was costing enterprises money. It's that simple. If Level 3 and Cogent were proposing a merger, the government would be singing a different tune.",
"The US Government did have trouble prosecuting Microsoft under antitrust law\n\nlol, that case is literally the WORST poster child for antitrust provisions.\n\ntl;dr nothing happened, after it stopped being popular in the media Microsoft and the US Government did nothing. 6 years later Microsoft and the industry were simply using different OSs and Internet Explorer remains a problem to this day",
"At the time, Microsoft simply did not lobby Washington. NBC-Comcast and TWC, on the other hand, has funneled oodles and oodles of money towards Obama's election and reelection (through PAC'S). Now the result of that is an FCC Chairman that is a former telecom industry lobbyist - Tom Wheeler. That is how things work (and have worked for decades and decades) in Washington DC. ",
"They had a lot of trouble prosecuting Microsoft. From what I recall, according to the letter and spirit of the law, Microsoft should have been broken up into one or two companies (Windows=MS1, Office=MS2 was mooted). That ended up not happening. Why exactly I don't know. The last time a real major breakup happened? AFAIK that was in the telco industry, when they broke up [Ma Bell](_URL_0_). Possibly the relevant US authorities have since become toothless and spineless.",
"Top comment says is best. \nTechnically, Microsoft was a monopoly in the field of computing, although I understood it to be that they simply had a much better product and had a right to market their own product how they wished.\nAs for Comcast/TWC, they are taking non-competing lines (like two different branches from the same tree) and labeling them as one of the same company. In this sense, however, they would have a greater majority of branches (lines) of the tree (internet). We suppose they are going to undermine competition much the same as Microsoft EXCEPT I think this has GREATER harm.\nFor homeowners, needing a computer in the '90s was a luxury. It really wasn't needed unless you had a very good job....in which case you could easily afford any such products. In today's modern society, it is essential to have internet if you are not a senior citizen/not retired. In fact, it is being debated as being treated like a utility. For this reason, we are much more weary to monopolization. I do question then why some of my other utilities are essentially monopolized (electric!). In my area at least, there are a 2-3 cable providers whereas I am only familiar with DTE for electrical. \n\nIn summary, it is more of a concern of Comcast growing their customer base and dominance over the cable industry. This doesn't change the fact that they already have monopoly over what seems like most of the country. The pie is just getting a little bit bigger. ",
"Most of the explanations on this post target actual 5 year olds. Only 5 year old kids would believe this is not about the amount of money Microsoft used to spend lobbying before the lawsuit (about $0) and after (tens of millions). The judge on the Microsoft case could not be more convinced of Microsoft's guilt, and outside of Judge Judy I have not a judge that upset since. The man was fuming, the decision was replaced by the consent decree, and Microsoft was not broken up.\n\nTWC already spends tens of millions already, and that is the part they have to declare. The whole argument that this does not reduce competition is a gigantic piece of bullshit when you think that Bell did not compete with anyone when it was broken up. It was just too big, period.",
"Now that's an expert response. You know the reason most people are against that merger is because Comcast is one of the worst companies in America apparently. I've never heard anyone complain about one company more. So obviously, they don't want to see a company like that get any bigger. My advice to all those Comcast customers. Disconnect it.\n\nYou will be surprised how easy it is to live without cable. When it hit $40 a month in Oklahoma, about 10 yrs ago, I said to hell with that. I'm not paying $40 a mth to watch tv.",
"There is a logical fallacy in your question. The merger is proposed but has not happened yet. The government (FCC) may not approve it for exactly that reason: That it is anti-competative. \n\nMicrosoft was sued because they grew (mostly organically) to dominate both the PC operating system market and the browser market. They were requiring PC manufacturers to preinstall their browser and not any of their competitors. Very different scenario from Comcast who is trying to buy a competitor.",
"The US Government doesn't care to actually govern us anymore and they all just use their positions as \"leaders\" of this country to double and triple their millions by taking bribes (lobbying) and using their insider knowledge gained by various committees that they are on to unethically sell information that would have an average citizen locked up for insider trading. Our celebrity elite government is above the law and the epitome of the class problem in this country. Both parties are equally guilty of this.",
"We like to tell ourselves that people who say the government is corrupt are exaggerating or \"conspiracy theorists,\" but the honest truth today is that the current FCC Chairman was placed there by Comcast as their personal puppet via millions in illegal bribes, but nobody wants to prosecute the matter, as there are too many guilty parties, and rubbing the wrong person the wrong way will get your fired.",
"There are some major differences. Microsoft's antitrust case was designed to set an example while the internet was still new. Microsoft had competitors that could lobby against it. It was a more flexible time.\n\nFast forward to today. Comcast and TWC have enough clout with government officials that any potential threat to their monopoly is easily dispatched. Telecom is an infrastructure based service, which gives Comcast and TWC a huge amount of leverage with any government agency or official.\n\nNobody in the government or big telecom gives a fuck about the internet as long as they can go home, watch buffering BSG reruns, and jack off to 480p porn. I pity the souls who cannot dream of playing Counter-Strike at 256 tick with no ping. The same creatures who cannot fathom the vast implications of the Oculus Rift.",
"In the end Mircosoft used its position in the market to prevent other companies from either entering the market or making money in the market. Specifically they shipped IE for free with every copy of windows esentially blocking customers from Netscape (which at the time was not free). Comcast has not used it's power to prevent anyone from entering the market or to block their business (see Google Fiber). I'm No fan of Comcast, and this deal should be examined closely for what it will do to the market, but it's not based on abuse of monopoly power. The other wrinkle is that we basically give this companies a monopoly over sets of territory in exchange for fronting the money to build the infrastructure.",
"because you shits arent burning the white house yet :s\n"
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[],
[
"http://www.newsmax.com/Newsfront/Google-conservatives-donating-GOP/2014/01/23/id/548771/"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"http://influenceexplorer.com/organization/microsoft-corp/f1244474fad44ad9a3a57859b4a709b1"
],
[],
[],
[],
[
"http://www.reuters.com/article/2009/03/06/us-wholefoods-ftc-idUSTRE5253AL20090306"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"http://en.wikipedia.org/wiki/Ma_Bell"
],
[],
[],
[],
[],
[],
[],
[],
[],
[]
] |
||
66kr94
|
- recently scientists observed negative mass. what is the significance of this? is this anti-matter?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/66kr94/eli5_recently_scientists_observed_negative_mass/
|
{
"a_id": [
"dgj81yk",
"dgj83sl"
],
"score": [
7,
3
],
"text": [
"No, it's regular old matter, with regular old positive mass. What they did, was through difficult techniques, induce the bulk of the material to behave *as though it has* negative mass. It does not, however. Additionally, anti-matter has positive mass. ",
"The mass isn't negative, the inertial mass is. If you put it on a scale or something you'd still get a normal reading. However, if you gave it a push, it'd move in the opposite direction instead.\n\nThis is why scientific journalism sucks."
]
}
|
[] |
[] |
[
[],
[]
] |
||
5zgszh
|
after a snow storm, why does the sky emanate a pink/gray hue throughout the entire night?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5zgszh/eli5_after_a_snow_storm_why_does_the_sky_emanate/
|
{
"a_id": [
"dey2pbj"
],
"score": [
2
],
"text": [
"In dry conditions, the light from sodium vapor street lamps is mostly absorbed by the dark pavement or soil/grass.\n\nWhen the ground is snow-covered, much of that light is reflected upward, where it illuminates the cloud cover or even the water vapor in the atmosphere.\n\nEdit: Made longer to satisfy the auto-moderator."
]
}
|
[] |
[] |
[
[]
] |
||
2rn1ec
|
What percentage, roughly, of settlers in what is now the US prior to the War of Independence were indentured servants?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2rn1ec/what_percentage_roughly_of_settlers_in_what_is/
|
{
"a_id": [
"cnhflr3"
],
"score": [
3
],
"text": [
"Across the total area of the future United States, indentured servants probably made up roughly 40 - 45% of all European migration before independence. In the early period of colonisation, this figure would have been much higher; as many as two-thirds of all free European migrants may have been indentured servants in the early seventeenth century, but very few would have been by the time of independence.\n\nThe proportion of indentured servants in the wider population would have been much lower by the time of independence. Not only were fewer and fewer servants coming to the continent as time went on, but the nature of indenture as a temporary condition means that every servant arriving in the US eventually became a free subject (if they lived long enough).\n\nMost of this decrease in servant numbers would have already taken place by the dawn of the eighteenth century, as the institution of slavery developed and began to assert itself. By the time of independence, indentured servants would have constituted only a very small portion of the workforce; probably less than one-twentieth in most cases."
]
}
|
[] |
[] |
[
[]
] |
||
87ixvq
|
what's happening when my back "pops" and is it bad?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/87ixvq/eli5_whats_happening_when_my_back_pops_and_is_it/
|
{
"a_id": [
"dwd5e9g",
"dwdjudn"
],
"score": [
5,
3
],
"text": [
"Usually, when bones 'pop', you're basically popping very small air bubbles between your bones (or at least that's the best theory we've come up with). Your back popping is not a big deal if it happens rarely, but if it happens regularly it could be a sign of back problems, especially if it hurts.\n\nDon't be scared about this though (ik how scary looking up health conditions on the internet can be), but if it's just the popping, it's usually nothing too bad. It's probably just a sign of straining your back a lot of maybe unhealthy sitting or sleeping positions. Try to fix these things and the popping should decrease.",
"Directly, it's not 'bad'. As above, it's just air bubbles in joints. Completely normal. However, when you 'pop' your own back - which is essentially known as a 'manipulation' - you are often only manipulating the vertebral joints that have the greatest range of movement by comparison to the other ones in your spine. This means the joints that have a more restricted range of movement are not being manipulated, as you essentially 'miss' them. So over time you end up with some joints that are hypermobile by comparison to the ones that you missed. This isn't necessarily a bad thing, but as a result, the muscles of your back often have tighter, more restricted resting and active states (because your body naturally makes compensations for imbalances or restrictions in movement to help it work as effectively as possible). \n\nTherefore: you are more likely to suffer from postural or mobility issues later down the line - not because cracking your joints has lead to arthritis or other degenerative musculoskeletal disorders (you've probably been told you'll get arthritis by popping joints, which is mostly false), but because your body is suffering from muscular imbalances and overcompensations as a result of some joints that haven't been popped being very very restricted.\n"
]
}
|
[] |
[] |
[
[],
[]
] |
||
bvig0h
|
why can my laptop pick up my wifi very well, but my phone, on the same desk, hardly connect at all?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/bvig0h/eli5_why_can_my_laptop_pick_up_my_wifi_very_well/
|
{
"a_id": [
"epperz6",
"eppmbul"
],
"score": [
11,
7
],
"text": [
"I would only assume better hardware in the laptop given its increased form factor.\n\nSame reason you won't get a core i9 and 32gb ram in a smartphone.\n\nEdit - forgot to add phones are more power conscious so reduce performance of areas to prolong life.",
"Laptops are larger so they can fit a bigger and better wifi antenna, usually the wifi antenna is built into the edge of the laptop's monitor."
]
}
|
[] |
[] |
[
[],
[]
] |
||
1xatm8
|
why lack of genuine industrialization in Argentina?
|
The way I see it, Argentina has never gotten properly industrialized (even compared to similar settler countries like Australia or Canada) for a couple of groups of reasons - 1) not the right social and institutional factors (e.g. large rural landowners being more predominant in Argentine affairs than the urban middle classes or rural family farms; civil society being weaker than the armed forces - in both cases, the other way around in the Anglo countries) and 2) the almost total reliance on agriculture for exports (vs. minerals on top of agriculture for Australia, say) and the lack of backward linkages to agricultural exports as compared to mineral exports.
Of those groups of reasons, is it the first which is the more important reason? In other words, was it the way Argentine society was structured, more than the almost total reliance on agricultural products for export and corresponding lack of backward linkages, that contributed to the lack of authentic industrialization in that country?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1xatm8/why_lack_of_genuine_industrialization_in_argentina/
|
{
"a_id": [
"cf9thdv"
],
"score": [
14
],
"text": [
"This is a very good question, but it is challenging (perhaps impossible) to answer. Before delving into a response, I would like to point out some pragmatic challenges that make answering it especially difficult. First, historians and economists have been debating your question for almost a century and so far have been unable to come up with a consensus. As you know, the process of industrialization takes a very long time to occur. It goes through vicissitudes of expansion, contraction, and depression. It is subject to intervention by governments and outside forces. And it often butts up against traditional culture. To further complicate the issue, “industrialization” looks different depending on where in the world you are. German industrialization is different than Canadian industrialization, which is in turn different than Chinese industrialization. So saying there is a “proper” or “genuine” way to industrialize really isn’t fair because it is subjective. This assumes that Argentina has failed. Though many people feel this way, it is not necessarily the case. One could argue that in spite of overwhelming challenges, Argentina has managed to soldier on and maintained a high standard of living in the process.\n\nAlso, keep in mind that as historians, it is easier to explain why something happened than to explain why something didn’t happen. Proving why something didn’t happen brings all sorts of hypotheticals into the equation, which isn’t really what historians like to deal with. Finally, how far back should we go to answer this question? I have seen discussions on AskHistorians about industrialization in Europe and its roots in the Middle Ages. Historians often debate the role that the wars for independence and civil wars had on initial industrialization in Argentina. One could also discuss the 19th century positivism which emphasized comparative advantage, order, and progress (the motto that is enshrined on Brazil’s flag). Comparative advantage encouraged developing countries to focus only on what they did well, thereby neglecting the diversification of their economy. Identifying when “industrialization” actually failed is really hard because its roots stretch from the present to the discovery of the New World! \n\nThat being said, it seems that you are more interested in understanding why Argentina did not develop following their rise around the turn of the 20th century. I’ll build my answer around that idea. You’ve identified two key reasons why industrialization has been so challenging in Argentina. First, Argentina’s economy during the 19th century was driven by agriculture. Michael Johns, in his article “Industrial Capital and Economic Development,” sees this as the key problem of Argentina’s economy. He argues that despite the wealth acquired during this period, the export economy prevented the development of social and financial institutions that could help aid the process of industrialization. I’m a little skeptical of your assertion that the emphasis on agriculture came at the expense of mining. Argentina has very scant mineral reserves. Unlike Chile, Argentina became an agricultural economy because it could not be a mineral driven economy. Thus, by the end of the Argentine “golden age” wealth was centralized on the Pampas and in Buenos Aires at the expense of the periphery. Di Tella and Platt’s book The Political Economy of Argentina, 1880-1946 examined the early twentieth century, especially agriculture. It showed that the “golden age” of Argentina was much more complicated than one might expect. Economic development was uneven, and many Argentines were deeply pessimistic about their country’s economic future. Yet, there still was a thriving middle class, who struggled through the Great Depression and exist today. The Great Depression and World War II altered the world economy. Argentina’s economy was so heavily invested in the old model that it never fully recovered. The world economy was suddenly predicated on a completely different set of concerns to which Argentina then had to adapt.\n\nThis brings us to your other point about social and institutional factors. This is, of course, hotly debated in the historiography. Juan Perón took power, who in turn was expelled by the military, who eventually was replaced by democratic leaders culminating with Carlos Menem, the “Washington Consensus,” and neoliberalism, which in turn brings us up against the twenty year rule. These periods all bleed together, and their social and institutional moves depended on those inherited from its predecessors. With each successive change, new institutions were established that focused on distinct social groups, which created a “stop and go” environment for industrialization. The social structure then played a key role in dividing Argentine society, which in turn led to the rapid change in economic policies.\n\nYet, I also want to complicate your points. First, industrialization in the middle and late twentieth century is intimately tied to governmental policies. Though the agricultural businesses struggled with the Great Depression, Argentina’s industries actually benefited greatly from both the Great Depression and World War II. They created vacuums of industrial goods which had previously been imported from the United Kingdom and the United States. The hole in industrial imports was thus filled by Argentine industries. How fortunate that in its moment of weakness, Argentina’s economy was buoyed by new opportunities! Perón and later leaders essentially created an artificial vacuum by implementing subsidies for Argentine companies while keeping tariffs high. Thus, Argentine products found a market despite being inferior in quality. On the open market, their industries had no chance, but with this move, Perón insulated Argentina against foreign competition. Argentina’s economy turned inward. Unfortunately, as Carlos Waisman’s book Reversal of Development in Argentina pointed out, Peronism thus became the scapegoat for economic failure. Waisman especially identified the frequent changes in economic policy, import substitution, and removal of government support for agricultural development as key to this disaster.\n\nUnfortunately, once Perón was removed from power, this led to all sorts of macroeconomic problems. The economy became volatile as the military reversed these changes. Thus, the market was suddenly flooded with industrial goods that were cheaper and superior to those being produced by Argentine industries. They failed to protect the gains that Argentine industries had made in the post war years. The economy was racked by hyperinflation, unsustainable wages, and price fixing. Furthermore, reduced assistance to agricultural sectors led to a depreciation of their competitive abilities. This in turn fanned the social flames. Finally, the left itself struggled to create a unifying platform and eventually spawned moderates and radicals alike. Even when Perón returned, he could do little to reverse the chaos or gain control, eventually leading to the chaos of the final military dictatorship. Yet, the military also failed. They never went full “neoliberalism.” In fact, one could argue their management of the economy was even worse than Perón’s, leading to perhaps the biggest economic bubble in Argentine history. So another reason that industrialization struggled was poor economic management by each successive government. \n\nTheir actions then created an “alternative reality” of what industrialization looked like. In my opinion, this must be understood in the Argentine context. Comparing industrialization to the United States, Australia, or Canada ignores the contexts that each of these nations dealt with. It paints these nations in a positive light (and Argentina in a negative light), even though they too had many internal challenges. Argentina lacks the natural resources of the United States and lacked the Commonwealth of Nations’ oversight that Canada and Australia benefited from in the middle of the twentieth century. Argentina instead had to go its own way. Though it struggled, it was far from a complete failure. Perhaps a better question would be: Could industrialization ever have looked the same as it did in other “settler” countries? I don’t think so. It ignores the political, social, and cultural setting in which Argentine industrialization occurred.\n\nFinally, I want to point out that recent historiography on the topic has been reexamining industrialization, especially in light of the perceived failure of neoliberal reforms. They have been reinterpreting industrialization itself. For example, James Brennan’s recent article “Prolegomenon to Neoliberalism: The Political Economy of Populist Argentina” argues that the question of industrialization is too closely tied to partisanship in Argentine history. Other works have looked at terms of trade, finance, and concentration as they relate to industrialization and demonstrate the complexity that industrialization took at the local and international levels. All of these are hot topics in Latin American historical circles at the moment. You might want to check out The Oxford Handbook of Latin American History, which has a chapter on the historiography of economic and industrial history. It might provide you with some valuable works to add to your understanding of industrialization in Argentina and see how recent studies are fleshing out other problems and successes of Argentine industries. "
]
}
|
[] |
[] |
[
[]
] |
|
25w87m
|
What was the significance, politically, of Israel instigating the '67 War with a preemptive strike on Egypt?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/25w87m/what_was_the_significance_politically_of_israel/
|
{
"a_id": [
"chldi4x"
],
"score": [
2
],
"text": [
"I'd love to answer, but I want to make sure I know what you're asking for before I get into it. Are you referring to the significance in terms of how other nations perceived it, how it affected Israel's relations with other nations, or how it was perceived in Israel? Or is it some combination of the three? If none, please let me know :).\n\nAs soon as I know which you're asking about, I'll get into it, just don't want to overload you with information ;)."
]
}
|
[] |
[] |
[
[]
] |
||
agakop
|
Why do we need bigger 'colliders' to smash particles together harder?
|
Why do colliders need to be be bigger and bigger to smash particles together harder - why can't they be accelerated faster around a smaller ring?
Also, I thought they were already accelerated to basically light speed ( 0.999999991 *c* ) in the Large Hadron Collider (LHC) - why is a bigger ring needed to go faster/harder given they're already at light speed - going only 0.000000009x light speed extra/faster seems only a tiny improvement for a 10x the size ring? what's the point?
Inspired by news scientists want to build a collider 10x the size of the LHC [_URL_0_](_URL_0_)
|
askscience
|
https://www.reddit.com/r/askscience/comments/agakop/why_do_we_need_bigger_colliders_to_smash/
|
{
"a_id": [
"ee4vyfp",
"ee4zrn8",
"ee52z45"
],
"score": [
9,
10,
3
],
"text": [
" > why can't they be accelerated faster around a smaller ring?\n\nWe are technologically limited. The faster the beam particles are moving, the stronger bending magnets are needed to curve the beam at a given radius. This is what limits ion beams, the strength of the magnets. For electron beams, they are easier to bend at a given radius than ions with the same velocity, because the electron mass is so small. However a circulating charge emits synchrotron radiation with an intensity proportional to (E/m)^(4)/R^(2), where E is the energy, m is the mass, and R is the radius of curvature. So electrons radiate extremely strongly at collider energies, and increasing the radius helps to mitigate that.\n\nAs for your question about velocities, the increases in speed are incremental because of the way that velocities near c add, however the increases in energy can be quite large. For example, increasing proton collider energies from ~ 10 TeV to ~ 100 TeV would offer a lot of potential new physics.",
"\\ > Also, I thought they were already accelerated to basically light speed ( 0.999999991 c ) in the Large Hadron Collider (LHC) - why is a bigger ring needed to go faster/harder given they're already at light speed - going only 0.000000009x light speed extra/faster seems only a tiny improvement for a 10x the size ring? what's the point?\n\nThe technological reason for larger colliders has been addressed. Let me answer this part in more detail.\n\nThe energy gained from increasing velocity goes up asymptotically as you approach light speed. In our normal intuition, what matters is how much speed you already have. Adding a fraction of a percent to your speed will only add a fraction of a percent to your energy. But in relativistic physics, when you're approaching light speed, that intuition is wrong. What matters is really *the difference* between your speed and light speed. If you go from 0.999999991c to 0.9999999991c (one extra nine there), the difference goes from 0.000000009c to 0.0000000009c. The *difference* is then *ten times smaller.* This approximately triples the resulting energy. If you divide the difference by 10 again - advancing an even smaller fraction closer - you'll triple the energy again, and so on.",
"yup, @RobusEtCeleritas stated this already but I think the point can be made clearer:\n\n & #x200B;\n\nWhat limits the energy in colliders is the synchroton radiation. Charged particles emit radiation as they are accelerated. Bending charged particles (they need to be charged if we want to influence them with our magnets) is like accelerating them, thus charged particles on curves emit radiation. A sharper curve emits more radiation than a less sharp curve. So a charged particle in a curve loses energy!\n\nNow you say, whats the matter, the particles are already *nearly* the speed of light, who cares about the extra promille? But particles dont radiate according to their *velocity* but according to their *energy.* And the energy of the particles could go up to infinity! Or rather its gamma factor to speak in relativistic terms.\n\nSo you if you want to excess physics at 100TeV, you need two beams at 50TeV (energy). If you try to achieve that in a small circular accelerator you wont get the particles to 50TeV, they will just radiate everything away in the first place. Make the ring larger and its \"easier\". Or build a linear accelerator in the first place.\n\nCheck [this](_URL_0_) e.g. for formulas."
]
}
|
[] |
[
"https://www.bbc.co.uk/news/science-environment-46862486"
] |
[
[],
[],
[
"https://www.lhc-closer.es/taking_a_closer_look_at_lhc/0.synchrotron_radiation"
]
] |
|
3tb3yr
|
what policies and systems are (or aren't) in place to help veterans? who is responsible for the aid and implementation? why do so many vets seem to end up homeless or worse? how can people help them?
|
This is regarding US vets. Sorry rest of the world. Though feel free to add what systems are in place in your country as well. I was just wondering because so many people are bitching about why we should help veterans before refugees and it had me wondering about these questions and how I can help. As that little girl says, "Why not both?" I'd like to help both refugees and veterans.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3tb3yr/eli5_what_policies_and_systems_are_or_arent_in/
|
{
"a_id": [
"cx4yf5e"
],
"score": [
2
],
"text": [
"We have programs and tools in place to help veterans. The GI Bill pays for school, there are housing vouchers, and many companies are actively seeking to hire veterans. Reducing veteran homelessness and unemployment is something that requires a little (not even much) effort on the part of the veteran.\n\nSource: I'm a veteran and currently using my GI Bill."
]
}
|
[] |
[] |
[
[]
] |
|
zzwin
|
- how does my body know how to do things that i can't control?
|
How does my heart know how to beat, my blood knows to respond to a wound. Is it possible to take control of these things?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/zzwin/eli5_how_does_my_body_know_how_to_do_things_that/
|
{
"a_id": [
"c69bwvt"
],
"score": [
2
],
"text": [
"There is a part of the brain dedicated to \"automated\" functions of your body. Like a separate computer processor, it keeps track of things like the heart beating, intestines constricting to digest and move food, etc. Some things you can control to a certain extent; controlling your breathing can raise/lower your heart rate, for example.\n\nOther things you cannot control, like your blood reacting to a wound. Such actions are chemical. When you get cut or injured, the barrier that keeps your blood in place is removed. The blood \"spills\" into the open areas and reacts based on what are called \"intrinsic factors\" or the \"intrinsic pathway\". \n\nWhen blood touches air, the factors are set off in a chain of sequence that allows your blood to clot and start the healing process. Sometimes, a person is missing an intrinsic factor, and the chain is broken causing problems such as Hemophilia or Von Willebrand disease."
]
}
|
[] |
[] |
[
[]
] |
|
35uoc5
|
in what order should you brush, floss and mouth wash?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/35uoc5/eli5in_what_order_should_you_brush_floss_and/
|
{
"a_id": [
"cr7z8k1",
"cr7zfp8",
"cr7zut8",
"cr7zwzl",
"cr80of2",
"cr83ymq",
"cr84sma"
],
"score": [
56,
9,
6,
3,
7,
2,
2
],
"text": [
"Just doing them in any order is better than not at all, but according to my dentist:\n\nFloss\n\nBrush (spit, don't rinse)\n\nSkip mouthwash, especially if it has alcohol. Use it in the middle of the day to \"freshen up\" in need be.",
"[According to the ADA:](_URL_0_)\n\n > Should I brush or floss first?\n > \n > Either way is acceptable as long as you do a thorough job. Some people brush their teeth and unfortunately skip flossing because they think their mouth feels clean or they may be short on time or tired and flossing is postponed. That’s not a good idea.",
"Flossing is the key. Before or after brushing, just do it!\n\nI prefer to do it before to get any chunks out. Doing it after makes sense because it should get more of the remaining toothpaste between your teeth. However the sodium whatever the fuck can irritate your gums if left on.\n\n",
"The order you listed in your title, personally; brush to remove most of the plaque and food, floss to get the rest, and mouthwash to disinfect any small cuts or irritated spots from the flossing.",
"All of you guys are missing one thing.\nThe order goes, \nFloss, Brush front and back of teeth, brush tongue, mouthwash",
"I brush, then floss (with the toothpaste still in my mouth). I have (and have always had) sensitive teeth, so I use a desensitizing toothpaste. Flossing with said toothpaste still in the mouth pushes the chemicals from the toothpaste well between my teeth (which, incidentally are extremely tight, making flossing quite difficult). Followed by a fluoride alcohol free mouthwash.",
"I was looking into alcohol-free mouthwash and I found out that [one of the main antiseptics can become deactivated by common toothpaste additives](_URL_0_), so if you're using one of those it's recommended that you put 30 minutes between brushing and rinsing regardless of the order."
]
}
|
[] |
[] |
[
[],
[
"http://www.ada.org/en/science-research/ada-seal-of-acceptance/product-category-information/floss-and-other-interdental-cleaners"
],
[],
[],
[],
[],
[
"http://en.wikipedia.org/wiki/Chlorhexidine"
]
] |
||
qd2dt
|
Can anybody help me identify a type of helmet?
|
I'm decoding a frontispiece of Vondel's 'Lucifer' (1656). I've found quite a few references, but my knowledge of military history is insufficient to identify [this helmet](_URL_1_).
Can someone link these types of helmets to a certain army or people? Or is this just a generic depiction of a helmet?
I would think it's a Spanish helmet? But I haven't found any exact copies.
Your input would, once again, be much appreciated!
For those interested, [here](_URL_0_) you can find the full frontispiece.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/qd2dt/can_anybody_help_me_identify_a_type_of_helmet/
|
{
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"text": [
"_URL_1_\n\nIt does indeed look a bit like a Morion, albeit a stylized one. It also looks a bit like the top of a [pikeman's helmet](_URL_0_), which were common for footsoldiers.\n\nI think there is an early modern warfare tag somewhere in here, but I do not believe you can link these to a specific army. It looks pretty typical for that time period, but I'm more familiar with late medieval than early modern warfare. But I feel I see conquistador helmets depicted more or less everywhere.",
"Ok, well, we have to take a full further back look at the art of the era, as well as the views of the Archangel Michael as seen during that era.\n\nWhy Michael? Michael has often been described as the angel who cast out Lucifer from heaven and was lead of God's armies during the battle for heaven.\n\n[This is a statue of Michael in Roman Garb](_URL_2_). Note the similar helmet. Roman, but without the side peices. [Here is a similar period peice](_URL_9_), where he wears a similar helmet and Roman guard. \n\nFrom these illustrations, we can determine that art of the period depicted angels, especially warrior angels in a Romanesque fashion as was common for soldiers seen in [Baroque art](_URL_5_).\n\n\nWhy is it important to look at Michael? Lucifer and Michael in popular tradition are of the same caste of angels, Archangels. Now, if you are familiar with the styles and themes of 1600's art, Michael is often shown in Roman/Greek style armor.\n\nNow, if you look at the top of the helmet for Lucifer, you will see his star, being the \"Morning Star\". This being his crest. Now, looking at helmets of the Roman period it appears to be more stylized than practical...but then we are looking at religious art.\n\nSo, it appears to be an embellished version of other the classic Greco-Roman style helmet with the ear pieces missing. Or a stylized, medieval/Renaissance helmet; [The Burgonet](_URL_6_), [Capeline](_URL_1_), [Morion](_URL_7_). [This](_URL_3_) is probably the closest helmet I could find that looked like it. [This one is similar as well](_URL_0_). Oh, [here is a great one](_URL_8_) done my Da Vinci. [A good statue from Venice](_URL_4_)\n\nThe reason I call this a Burgonet, is because the Morion style did not really show up until the mid 1600's, while Burgonet's had been around for about 100-200 years, making them more common, since metal armor was expensive, and would be used until it practically couldn't be used anymore, giving them very long and traveled lives. \n\nSo I would say that the helmet is a stylized Burgonet Renaissance style helmet, with influences from Baroque preferences for Greco-Roman armor in depicting St. Michael/Lucifer, with his moniker of \"Morning Star\" for his crest."
]
}
|
[] |
[
"http://i.imgur.com/Z4fmL.jpg",
"http://i.imgur.com/1kw7b.png"
] |
[
[
"http://en.wikipedia.org/wiki/File:Burgonet_at_the_Met.png",
"http://en.wikipedia.org/wiki/File:Spanish_Conqueror_Helmet.jpg"
],
[
"http://www.wikipaintings.org/en/parmigianino/helmet-crossed-with-curved-strips-and-rosettes",
"http://en.wikipedia.org/wiki/Capeline",
"http://en.wikipedia.org/wiki/File:Michael4.jpg",
"http://ornamentedembellished.tumblr.com/post/12151935394/lostsplendor-parade-helmet-c-1543-click-for",
"http://www.paradoxplace.com/Insights/Equestrian/Equestrians.htm#Colleoni",
"http://commons.wikimedia.org/wiki/Category:Baroque_paintings_of_Saint_Michael",
"http://en.wikipedia.org/wiki/Burgonet",
"http://en.wikipedia.org/wiki/Morion_%28helmet%29",
"http://commons.wikimedia.org/wiki/File:Un_Condottiero_-_Leonardo_da_Vinci.png",
"http://en.wikipedia.org/wiki/File:GIORDANO,_Luca_fallen_angels.jpg"
]
] |
|
23l5do
|
When did women begin painting their nails?
|
My friends and I are having this discussion and we have (we think) learned that in the US women began using nail polish in the 30's after the creation of auto paints.
But that can't be the start...so when did it begin?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/23l5do/when_did_women_begin_painting_their_nails/
|
{
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"cgy3w9f",
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"text": [
"If you're interested in nail *polish*, you're on the right track with the automotive paint thing. Clear nail polish was invented in the 20s, and colored nail polish developed in 1930. From [\"COSMETICS AND SKIN CARE PRODUCTS : A Historical Perspective\"](_URL_0_):\n\n > Nail enamel or polish is useful for nail adornment, covering nail discolorations, and providing strength to weak nails. Nail polish was introduced in the 1920s when lacquer technology was developed. During World War I, excellent sources of nitrocellulose were developed as a military explosive. The nitrocellulose was created by reacting cellulose fiber, from cotton linters or wood pulp, with nitric acid. It was discovered that boiled nitrocellulose could be dissolved in organic solvents. After evaporation of the solvents, a hard, glossy film of nitrocellulose was produced, known as a lacquer. Extensive research on nitrocellulose lacquer was undertaken by the automobile industry, which found the product preferable to slow-drying, oil-based paints previously used to paint cars. This technology was adapted directly to the cosmetics industry.\n\n\n > Before 1920, nails were manicured, then polished with abrasive powder to achieve a shine. Color was then added through the use of stains. The first lacquer marketed was clear and labeled a nail polish because it imparted a high shine to the nail plate. In 1930, Revson developed the idea of adding pigments to the clear lacquer to form an opaque, colored nail polish. Based on the success of this poor-quality nail polish, Revson formed Revlon in 1932. He hired a formulation expert to develop a better product, which became known as nail enamel.\n\nHowever, as they note, women were coloring their nails long before the invention of nail polish. If you're interested in when any humans anywhere began to paint their nails, the answer is going to be in prehistory. But if you're interested in its rise in Western European countries or something along those lines, that's findable, I'm sure.",
"The act of painting fingernails was a common practice in Egypt by 3000 B.C. but it is believed that fingernail paint originated even earlier in China where the color of your nails showed what your social rank was. \n\nBy the third millennium B.C. the Chinese used ingredients such as gum arabic, egg white, gelatin, and beeswax to make varnishes, enamels, and lacquers. The color nails that determined you were royalty, according to a fifteenth-century Ming manuscript were black and red. Although in the Chou Dynasty of 600 B.C. gold and silver were seen as the royal colors. \n\nThis was also true with Egyptians where the color of your nails signaled what your social standing was. In Egypt red signaled great importance, Queen Nefertiti painted her fingernails and toenails a ruby red, Cleopatra favored a deep rust red. Women who were of lower social class were only allowed pale hues, no woman would risk having the colors that a queen had. \n\nPainting nails was also common for warriors of great importance. Egyptian, Babylonian and early Roman commanders would spend great amounts of time having their nails painted the same shape as their lips.\n\nThe great amount of attention ancients showed to fingernails and toenails suggests to most cosmetics historians that manicuring was already an established art. This is supported by excavations of royal tombs at Ur where manicure sets were found. \"Well-manicured nails became a symbol of culture and civilization, a means of distinguishing the laboring commoner from the idle aristocrat\". \n\nPanati, Charles . \"Atop the Vanity.\" In Panati's Extraordinary Origins of Everyday Things. New York: Harper & Row, 1987.",
"The Chinese were painting their nails as far back as 3000 BC, although specific class-based color identification (gold colored nails reserved for royalty, for example) was first recorded during the Zhou Dynasty (1046-256 BC). By the time of the Qin dynasty (221-206 BC) red (or black) seems to have replaced gold as the color intended for use by royalty/ nobility (Sherrow, 2001). It's interesting that social class restriction to nail colors were not just limited to ancient China, but also to places like Egypt, which suggests some universality of the concept of social ranking by nail color.\n\nOf course, the idea of class identification by fashion styles isn't just limited to nail color, almost every item associated with fashion at one time or another was also associated with social status (for example ermine cloaks for royalty) or caste delineation (for example the \"sacred thread\" of Hindu Brahmins). Some folks have gone as far as to suggest that the true symbolic purpose of fashion is to register and de-register individuals with respect to distinctions of class and social status (Davis, 1992).\n\n\nSherrow, Victoria (2001). For appearance' sake: The historical encyclopedia of good looks, beauty, and grooming. Phoenix: Oryx Press.\n\nDavis, Fred (1992). Fashion, Culture, and Identity. Chicago: The University of Chicago Press.\n\nEdit: I wonder if folks were painting their nails for functional reasons rather than cosmetic -- for example, musicians to strengthen their nails for strumming string instruments. A quick search didn't reveal any meaningful hits, maybe someone on this sub knows if nail-painting is purely a cosmetic activity or if there other historical + functional uses for painting nails."
]
}
|
[] |
[] |
[
[
"http://www.sciencedirect.com/science/article/pii/S0733863505702060"
],
[],
[]
] |
|
his8s
|
Thermodynamics, adiabatic expansion. (Joule-Thomson effect)
|
Wikipedia sais this on the topic of adiabatic expansion:
"In thermodynamics, the Joule–Thomson effect or Joule–Kelvin effect or Kelvin–Joule effect describes the temperature change of a gas or liquid when it is forced through a valve or porous plug while kept insulated so that no heat is exchanged with the environment."
And:
"In a free expansion, on the other hand, the gas does no work and absorbs no heat, so the internal energy is conserved. Expanded in this manner, the temperature of an ideal gas would remain constant, but the temperature of a real gas may either increase or decrease, depending on the initial temperature and pressure."
I have a container consisting of two identical chambers separated by a wall. One chamber contains methane at a certain temperature and pressure. The wall bursts and methane is distributed evenly throughout the container, there is no heat flow allowed out of the system.
This seems to be an adiabatic expansion, doesn't it?
When solving the energy balance:
dU = Q + W - PdV + sum of mass flow
yields
dU = -PdV
(i take my volume to be the initial chamber filled with methane, and i'm letting this expand)
The internal energy is not a constant as you can see here. Did i do anything wrong? Is this not an adiabatic expansion? If so, what kind of expansion is it?
|
askscience
|
http://www.reddit.com/r/askscience/comments/his8s/thermodynamics_adiabatic_expansion_joulethomson/
|
{
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"text": [
"In an expansion such as you described, it is indeed adiabatic as Q=0 (no heat flow).\nAlso as you described, the change in internal energy would be zero because the gas is expanding against a vacuum and if ideal by definition requires no work to accomplish.\n\nThink of it this way, the gas is not expanding by a broken seal, but a piston which applies a pressure of zero and has no weight.\n\ndU does equal -PdV, but P should really be labeled as Pe as this equation only applies to the external pressure which in this case is a vacuum where the external pressure is zero.\n\nSo dU = -PdV where P=0 thus dU=0.",
"The first law of thermodynamics only works for a closed system. If you start mixing fluids, you have entropy that is generated and can mostly only rely on PV = nRT.\n\nIf you consider the entire box as one system, you have dV = 0 therefore dU = 0.",
"A Joule-Thomson expansion is not at constant internal energy, it is at constant enthalpy. A free expansion is at constant internal energy as AsAChemicalEngineer pointed out. Both cases are adiabatic."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
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