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vgbnm
|
Is it possible that a virus could act as a vaccine for several other worse viruses?
|
I was thinking about how some people want their children to get the chicken pox, so they can't get it later in life.
Could it be possible that tribes kept a kind of tribal virus that they knew how to deal with, so that it would prevent us from getting worse diseases that were in the environment?
|
askscience
|
http://www.reddit.com/r/askscience/comments/vgbnm/is_it_possible_that_a_virus_could_act_as_a/
|
{
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"text": [
"You might be thinking of the development of the smallpox vaccine, in which scientists noted that milkmaids who were exposed to cowpox did not develop smallpox. They initially used the cowpox virus as a vaccine for smallpox since it induced an immune response against smallpox antigens. Now, they used the vaccinia virus, with a similar idea.",
"Someone who I work with is about to begin working on creating flu viruses that express antigenic proteins from other viruses on their surface to act as vaccines, or something along those lines.",
"as arumbar already pointed out, this is exactly the case with smallpox, modern small pox vaccinations actually contain the related virus *vaccinia* (smallpox is called *variola*). \"Vaccination\" actually comes from \"vaccinia\", natch.\n\nThis is less useful for virus that are more topologically varied, such as the flu virus; you might be vaccinated for one type of flu, and a very closely related variant might already be different enough that the vaccination doesn't protect you.\n\nedit: as for the \"intentional tribal reservoir\" idea you posit, I don't really know much about tribal peoples and their knowledge of disease, but I don't think any stone-age peoples were capable of such forward thought given their limited knowledge base"
]
}
|
[] |
[] |
[
[],
[],
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|
3cfenn
|
according to einstein's theory of relativity, events that occur at the same time for one observer could occur at different times for another. what does this mean? what are some eli5 examples?
|
I have trouble wrapping my head around this and similar concepts
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3cfenn/eli5_according_to_einsteins_theory_of_relativity/
|
{
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"csuz6mt"
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"text": [
"If you want to do further research on this, a good specific search phrase is the relativity of simultaneity. \n\nA common example is called the train and platform. \n\nImagine there is a box car, with open sides, and a shuttered lantern in the middle. There's a guy standing by the lantern, ready to open it.\n\nThe train is moving along the tracks, approaching a platform, where another guy is standing.\n\nAs the train car passes the guy on the platform, the guy in the train opens the shutters on the lamp. For the guy in the train car, the lamp, and the edges of the train car, are all stationary objects. Since the lamp is in the middle of the train car, it takes the light the same amount of time to reach the front wall as it takes to reach the back wall, since they are equally distant.\n\nTo the guy on the platform, the rear wall of the train is approaching where the light came from, and the front wall is receding from where the light came from, so the light will reach the rear wall before it reaches the front wall. It has a shorter distance to travel one way than the other.\n\nThis wouldn't be true if the light moving 'backwards' was slowed down by being emitted from a train moving forwards, but we can experimentally verify this is not the case, both observers would see both beams of light moving at the same speed, so the only alternative is that what is simultaneous for the guy in the train is not for the guy on the platform. "
]
}
|
[] |
[] |
[
[]
] |
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8v73wr
|
How does consuming caffeine compare to absorbing it through your skin?
|
If a person were to drink a mug of coffee while another person (who has the same sensitivity/tolerance for caffeine as the other person) rubbed his or her skin with lotion with a caffeine level equivalent to that of the mug of coffee, how would the effects differ in regards to intensity and duration?
|
askscience
|
https://www.reddit.com/r/askscience/comments/8v73wr/how_does_consuming_caffeine_compare_to_absorbing/
|
{
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"text": [
"We can change this question to \"How does swallowing Drug X compare to absorbing it through your skin?\"\n\nFirst of all, it's important to remember that our skin is pretty amazing at keeping things out. It is not a great absorber of substances, period. Most ointments and creams that you apply will find it very difficult to get to the dermis (the deep part of your skin), and extremely difficult to go deeper than that to big blood vessels.\n\nNow, most drugs have an ideal method of delivery. Some are absorbed through your gut, some by injection and some by breathing them in. Caffeine is at the end of the day, another drug, that is absorbed reasonably well through your gut.\n\nSo going back to your question, studies showed that about 2micrograms of caffein per square cm of your skin is absorbed an hour at best. Coffee's caffeine contents vary, from 100mg to 300mg in your triple venti coffee. Even if we go for 100mg, this is 50,000cm^2 of skin that we would need for the caffeine to get to the *first layer* of skin. In 1 hour! And we only have 1900cm^2 of skin in the first place! And, only a tiny amount of coffee is abosrobed in the first place.\n\nSo, if you just rub the same amount as what you'd drink, nothing would happen. Absolutely nothing except perhaps causing some irritation of the skin."
]
}
|
[] |
[] |
[
[]
] |
|
58o51w
|
who writes the stuff that goes in fortune cookies?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/58o51w/eli5_who_writes_the_stuff_that_goes_in_fortune/
|
{
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"d91xwhm"
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"score": [
2
],
"text": [
"Apparently, the [CFO of the company who manufactures the fortune cookies](_URL_0_). Maybe that's why they so often refer to wealth?"
]
}
|
[] |
[] |
[
[
"http://www.cnn.com/2016/08/02/us/fortune-cookie-writer-wonton-food-company/"
]
] |
||
2vq8jz
|
If a curveball was thrown in an obstacle-free, zero-gravity environment, would it follow a spiral pattern or return to the pitcher? If it's a spiral - does it curve inwards or outwards?
|
Alternatively, in the case that a curveball somehow requires gravity to function - if it was thrown from atop a high enough place, would it loop back to its origin point (disregarding altitude), or would it spiral?
|
askscience
|
http://www.reddit.com/r/askscience/comments/2vq8jz/if_a_curveball_was_thrown_in_an_obstaclefree/
|
{
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"cokbyv5"
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"text": [
"The curve of the ball is dependant on the resistance of the air to the spinning motion. All pitches take advantage of such resistance. A ball will even rise once it catches the air just right. A spinning ball in an space with air but without gravity would move in a curve until the air resistance stopped the spin. In a gravity free space the spin is independant of the angle of motion of the ball so spin would have no effect on trajectory. "
]
}
|
[] |
[] |
[
[]
] |
|
57gi6g
|
How were voters made aware of U.S. presidential candidates before radio and television?
|
What would influence voters to vote for a particular candidate?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/57gi6g/how_were_voters_made_aware_of_us_presidential/
|
{
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"text": [
"I've [written about this before](_URL_0_), but essentially, newspapers both shaped and were shaped by early political parties, and a national network of subsidized distribution through the postal service meant that most towns had access to multiple newspaper titles. To quote from that earlier answer: \n\n > Anyhow, in the years after Freneau and Fenno, partisans would often organize them around newspapers, and printing presses were some of the first things to arrive in new towns. The way that the system generally worked was that each party might find an enterprising local person to serve as editor of the paper, and a skilled printer to actually produce the paper (printers themselves, being ink-stained wretches who often had deformities related to the physical difficulties of printing, were not often party leaders). The editor/printer would print political news, party platforms, and write screeds against his opposing editor, and they would often be rewarded (if the party was in power) with patronage, in the form of postmasterships and printing contracts. Newspapers also printed party ballots, which was crucial in an era before standardized ballots provided by the government.",
"I asked a very similar question a month ago and got a good answer from u/lord_mayor_of_reddit\n\n_URL_0_"
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/3xozr6/in_early_us_history_how_people_made_decision_of/"
],
[
"https://www.reddit.com/r/AskHistorians/comments/4zr9pr/prior_to_radio_and_television_how_did_the/"
]
] |
|
54ryjb
|
Sex positions names in the last centuries (1200-1800)
|
I've been wondering about the evolution of sex positions names. I do not know enough books and pieces of writing of that time countaining such names, so I really have no idea.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/54ryjb/sex_positions_names_in_the_last_centuries_12001800/
|
{
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"d84vuqa"
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"text": [
"Let me offer a small window into the names of sex positions as one guide called them c. 1500.\n\nIn the summer of 1524, an artist named Giulio Romano was working on painting saints in the Vatican. In the spirit of bored workers and doodling schoolchildren everywhere, he decided to dash off 16 sketches of obscene character to amuse his friends. In the words of one contemporary, these sketches \"dealt with the various attitudes and postures in which lewd men have intercourse with lewd women.\" Had this been a century beforehand, a good number of rich and powerful nobles would have had a laugh at the sketches, passed them around to their friends, and then they would have disappeared forever. However, along with the printing press, another German technology with great and terrible potential had filtered down into Italy—engraving.\n\nInspired by the printing press, artists looking for mass reproduction had turned to carving a block of wood, filling the gaps with ink, and then pressing them on paper, resulting in what was called a 'woodblock print.' These woodblocks were capable of several thousand impressions, and were often colored in with watercolors or by hand. In fact, woodblocks were most often used to create playing cards. The downside to using wood was that the images would begin to fade and wear down after a few thousand impressions. Additionally, like with the printing press, demand very quickly outstripped supply, and an alternative method was needed. This alternative was found in copper, first by goldsmiths (who had a right to metal engraving under feudal law), and then by painters, the most famous and influential of which was Albrecht Dürer. Dürer, much like Aretino, realized that the developing middle class could not yet afford to own beautiful paintings or decorations, but they could afford copper engravings, which could be sold by the hundreds of thousands. \n\nAlthough Dürer was the first to realize the potential profits and fame, he was not the only one. One Marcantonio Raimondi (who drew our picture of Aretino above)\t, from Bologna, stole Dürer's engraving technique and used it to print a few hundred copies of Romano's dirty pictures, arguing in a letter to his friend that \"they will circulate, and [you and I] will at the same time become both rich and famous.\" And they did. However, Raimondi perhaps sold the engravings far too eagerly and recklessly, to every possible customer, which, even in Rome, led to his arrest and imprisonment by Clement VI. In a lucky break, his friend Pietro Aretino managed to secure his release. The thankful Raimondi showed Aretino the engravings that he had been imprisoned for, and Aretino declared that he was inspired by them, and wrote 16 sonnets to go along with them, dedicating them in a letter to “all hypocrites [such as Giberti], for I am all out of patience with their scurvy strictures and their villainous judgment and that dirty custom that forbids the eyes to see what most delights them. What harm is there to see a man possess a woman? Are the beasts freer than we?” The pairing of the engravings with Aretino’s dirty poems created something really unique—perhaps the first Playboy Magazine in all of history. \n\nThe combined work of these three men was a work called *I Modi* and it was explosive in its success, crossing Europe like wildfire and being translated and spewed into new editions for centuries. The origanls are largely lost, the British Library has the only recorded surviving ones from the second edition--you can see a picture here of the remainders:_URL_0_\n\nHowever in 1602, one Agostino Carracci made copies of the originals for a French translation. These editions that he captioned with the names of various Greek and Roman figures and god(desse)s are the versions that come down to us today. Their subtitles would go on to describe some sexual positions for the next century or so. For example, the position that we call wheelbarrow was termed the Bacchanal style in later pornography. Another, the Herculean described what we might call a standing position. I've compiled several of these in this imgur album [super NSFW]\n\n_URL_1_"
]
}
|
[] |
[] |
[
[
"https://upload.wikimedia.org/wikipedia/commons/e/ea/I_modi_raimondi.JPG",
"http://imgur.com/a/ehusq"
]
] |
|
6e9goo
|
why are some roofs shaped like this ? (northern france so not a snow area)
|
_URL_0_
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6e9goo/eli5_why_are_some_roofs_shaped_like_this_northern/
|
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"text": [
"Might want to check that link again. I'm not seeing any roof there. It just shows random stuff every time it loads.",
"What I'm interested in is why the gradient changes and not just stays constant like it does in other areas... ",
"The steep pitch at the top provides for better clearance of rain, debris, and in rare cases snow. The shallow pitch at the bottom prevents the eaves from going so low that they hit people in the head.",
"I believe this is called a [bonnet roof](_URL_0_), and the purpose is to give a little more eave coverage to keep water away from the foundation, and to provide shade for plants growing next to the house. The extra shade also helps to keep the house cooler. \n"
]
}
|
[] |
[
"http://imgur.com/a/NimpM"
] |
[
[],
[],
[],
[
"http://www.ehow.com/about_4672957_bonnet-roof.html"
]
] |
|
fcjx3p
|
what is a brokered convention and what would that mean for the u.s. democratic primary?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/fcjx3p/eli5_what_is_a_brokered_convention_and_what_would/
|
{
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"text": [
"In simplest terms, the nominees do not have a majority to become the \"Democratic Nominee.\"\n\nA convention occurs where negotiations go on behind the scenes to try to get other nominees to drop out while delegates continue to vote and revote until a majority occurs. For instance, perhaps one nominee will promise another nominee the VP spot or a cabinet spot.\n\nWhat does this mean? It means that whomever is picked in the end as the nominee for the Democratic Party does not have a united party behind them. If that person does not have a united party behind them, then most likely the other major party will win the election (because a lot of people will vote for someone else - like an independent).\n\nSo, if the priority is getting Trump out of the White House, the last thing the Democratic Party wants is a Brokered Convention.",
"In a nominating convention for a party's presidential nominee (i.e. the Democratic or Republican National Convention), it is required that a candidate receive a majority ( > 50%) of all the delegate's votes in order to secure the nomination.\n\nIf a candidate does not achieve this majority in the first round of voting, the convention becomes 'open' or 'brokered'.\n\nIn a brokered convention, all regular delegates who were pledged to a candidate (because of primary results in their respective states) are 'released', and can vote for whoever they like.\n\nIn the DNC this year this is important, because super-delegates (delegates assigned by the party leadership and not via primaries) cannot vote in the first round of voting. If an open convention happens, they would then get a vote."
]
}
|
[] |
[] |
[
[],
[]
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||
axavw7
|
What is rocket fuel and how do we get it?
|
I have no idea how I went 24 years of my life thinking rockets were powered on an alternate form of gasoline. From what I can gather rocket fuel is mostly hydrogen and oxygen in liquid and solid form. Seems to me these are two abundant resources. Can we run low once space travel is more common? I'm assuming we can refuel if we find ice or water on mars?
|
askscience
|
https://www.reddit.com/r/askscience/comments/axavw7/what_is_rocket_fuel_and_how_do_we_get_it/
|
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"text": [
"You’re not entirely wrong on the gasoline thing, believe it or not. IIRC, the first stage of the Saturn V was powered by a mixture of liquid oxygen (LOX) and kerosene. You’re also right about ice: you can electrolyse water into its base components, hydrogen and oxygen, and use that as fuel. Granted it’s not necessarily as simple as I describe it but that’s the gist of it. If you really feel like learning about rocket fuel, I suggest reading Ignition! An Informal History of Liquid Rocket Propellants by John Drury Clark. You can find the entire text online for free (can’t give it to you now, mobile). \n\nEDIT: [Here’s the book for you](_URL_0_) ",
"Many types.\n\nSolid fuel is usually ammonium perchlorate composite propellant (APCP) that burns aluminium. Additives include iron oxide catalyst, a binder like HTPB or PNAB that holds the fuel together and acts as secondary fuel, and epoxy curing agent. There are other solid fuels but APCP is the most efficient and widespread in space rocketry.\n\nLiquid fuels also have two distinct types.\n\n Hypergolic fuels ignite on contact and most of them are liquid at room temperatures, give or take. This means they aren't cryogenic and as such are used in deep space missions without evaporating. Examples include various hydrazine derivatives like UDMH or MMH. Oxidized by nitrogen tetroxide. Toxic. Hypergolic monopropellants exist that use a metal catalyst (iirc iridium or platinum, don't remember), these are usually used in maneuvering thrusters of space probes.\n\nCryogenic fuels refer to liquid oxygen and hydrogen components. They're not used past geostationary orbits since they evaporate in a matter of hours for hydrogen to couple days at most with extra insulation for oxygen. Other than hydrogen, kerosene is the most widespread and traditional fuel, with works on methane under way. Exotic paper designs of the past included fluorine oxidizers and pentaborane fuel - very efficient, immensely toxic, and a huge pain in the ass to store: fluorine is very corrosive. Main use for hydrolox and kerolox engines is ascent through geostationary transfer insertion. \n\nAnother type is noble gas used in electric engines, chiefly xenon. Miniscule thrust, immense efficiency. Used for attitude correction and station keeping of satellites or main propulsion for the DAWN space probe."
]
}
|
[] |
[] |
[
[
"http://www.sciencemadness.org/library/books/ignition.pdf"
],
[]
] |
|
1q7y2t
|
Is it easier to slow a car by holding the brakes, or by pressing and releasing them?
|
Just a thought I had today in the car.
You're driving 100mph, and you need to stop. If you put the brakes on, you're going from 100-0, thus creating more inertia (right?) and putting more stress on the brakes. But on the other hand, if you release and press the brakes every 20mph or so, you'd technically be slowing down from 80, to 60, to 40, and so on, instead of 100 to 0.
Am I overthinking this to much?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1q7y2t/is_it_easier_to_slow_a_car_by_holding_the_brakes/
|
{
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"text": [
"a few things.\n\nfirstly you're not 'creating more inertia'. inertia is a property of all bodies with mass which is just a consequence of Newton's Laws: a body will maintain its motion unless acted upon by a force, and the force required to achieve a certain change in velocity (i.e. acceleration = change in velocity / time) is F = mass * acceleration.\n\nIf you want to change the velocity of a car from v to zero you will have to provide a certain force for a certain time. It does not matter how you break up that time, everything is linear. So no, in that sense there is no difference between breaking all at once or breaking in bits.\n\nI think your question is inspired by the fact that if you're driving an old car without anti-lock breaks and going very fast or on slippery ground it makes sense to 'pulse' the break pedal to stop in the shortest possible time. (Anti-lock breaks automate that process.) \n\nHowever, that has its origin in an entirely different phenomenon. If you have an object lying on a surface then you need to exert some minimum force F = mu_s w to get it moving. w is just the object's weight, and mu_s is the *coefficient of static friction*. The bigger it is the harder the object is to move (so for example the coefficient of static friction of a tire on road is quite high, but of roller scates on ice is very small. It varies for each combination of materials.)\n\nOn the other hand, if an object is already moving and you just want to keep it moving at the same velocity you will have to apply a force F = mu_k w. (so for example you're shoving a box and you want to move it across the room.) w is again the weight, but now mu_k is the *coefficient of kinetic friction*. \n\nHere's the rub: the coefficient of kinetic friction is always less than the coefficient of static friction. This is why, when you're trying to move a heavy object by shoving it, getting it moving is the hardest part (you have to fight the larger coefficient of static friction). Once it moves it's less work for you to keep it moving.\n\nThis explains why you want to pulse the break. If you're going very fast and your tires roll without slipping then your tire surface does not actually move in relation to the road surface. So if you apply the breaks then the tires will exert force on the road, which in turn exerts a force back and slows down the car, up to the maximum force possible by the coefficient of static friction.\n\nHowever, if the breaking force exceeds that value then your wheels lock up and start to slip on the road. The coefficient of kinetic friction now dictates the maximum stopping force, which is smaller than before slipping and increases the time taken to come to a complete stop. So rather than breaking maximally hard, you should optimally break to the greatest extent that does not cause slippage. That's where 'pulsing the break' comes form. It avoids breaking so strongly that your tires loose grip on the road, therefore reducing the friction that stops your car. "
]
}
|
[] |
[] |
[
[]
] |
|
5b6dkl
|
Did Hispanics go to segregated schools in the southwest prior to brown v. Board?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/5b6dkl/did_hispanics_go_to_segregated_schools_in_the/
|
{
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"d9m68c8"
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"text": [
"Yes. But Brown v. Board of Education was not the ruling that ended the segregation. There are two types of segregation. One is \"de jure\" or by law segregation, meaning segregation based on laws on the books. The other is \"customary\" segregation, or segregation that was not based on laws but custom. California had de jure segregation, and was one of the earliest states to grapple with segregation, which makes sense since it had a large population of Hispanics. In Mendez v. Westminster, a 1945 case, the 9th Circuit Court of Appeals affirmed a decision that segregation of schools was unconstitutional. Brown v. Board of Education quoted Mendez and adopted much of its reasoning. In 1947, California's segregation of Hispanic schools ended. Following Mendez, a case in Texas, Delgado v. Bastrop Independent School District, led to a ruling that customary segregation was unconstitutional (Texas did not have de jure segregation). I am less familiar with the histories in the other states. I will note that the Treaty of Guadalupe required that Hispanics be classified as white in the Soutwest, which is why most segregation was customary, not de jure."
]
}
|
[] |
[] |
[
[]
] |
||
349tf0
|
Does the earth rotating have any effect on us seeing the clouds move?
|
Sorry if this is a ridiculous question.
|
askscience
|
http://www.reddit.com/r/askscience/comments/349tf0/does_the_earth_rotating_have_any_effect_on_us/
|
{
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"cqunzaw"
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"text": [
"Directly? No. It's *not* like the clouds are holding still while the surface of the Earth rotates beneath them. The entire planet and the atmosphere rotate together, conserving angular momentum. However...\n\nIndirectly? Yes. Unlike the surface, the atmosphere is free to move north and south. As the equator heats up from all the direct sunlight there, air moves towards the poles to redistribute that heat. Air that was once moving with same angular momentum as the surface at the equator has now shifted closer to the poles, and thus closer to the axis of rotation. In order to conserve angular momentum, then, it must start rotating faster, like an ice skater pulling in his arms. This helps create the prevailing westerlies, a.k.a. the jet streams, and explains why a lot of the weather at mid-latitudes (over most of the US and Europe) comes from the west and moves towards the east."
]
}
|
[] |
[] |
[
[]
] |
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3tdz29
|
How were illegitimate children viewed in medieval China?
|
I'm putting together a backstory for a D & D character who comes from a region analogous to China (Tian-Shu from Pathfinder in case anyone is wondering). My current backstory is that she's the illegitimate daughter of an upper class family and I'm just looking for a bit of real world history to flesh that out.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3tdz29/how_were_illegitimate_children_viewed_in_medieval/
|
{
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"text": [
"It depends on situation to situation. However, since your character is a female, she would be suffering a fair bit.\n_________\n\nIt ancient China, bloodlines are very important, and it links directly to the status of a person (as well as the inheritance that may come with it).\n\nA son born to the legal wife of a man would be considered the proper heir 嫡子, and would have first consideration in inheriting all estates and titles when the man passes away. This status would be irregardless if the age of any of the other sons the man may have with other women. As such, the proper heir would be pampered the most in the family, and given all the best benefits possible. Only when the proper heir has brothers by the same parents, would there be a question of inheritance.\n\nA son born to a concubine of a man 庶子 would be considered part of the family, but would not stand to inherit anything. If his mother was especially pampered, he may be allowed certain privileges, but these would still be considerably less than that provided to the proper heir. However, if the man has no son with his legal wife, the concubine's son may be promoted to be the heir, often through having the legal wife adopt the son as her own.\n\nA son who was illegitimate, however, would not be treated as part of the family at all. Although the term 庶子 was also used to describe such sons, if their mother was not married to their father, they would be regarded as outcasts, and most would not be even allowed to enter the family home. Even if the birth father did show some concern for the child by bringing him into the family, the boy would often be mistreated. As such, they would have no chance of inheriting anything from the family. The only exception would be if none of the man's wives or concubines have sons, in which case the illegitimate son would be adopted, but would have to cut off all ties to his birth mother.\n\nThe most famous examples would probably be the uncle-nephew pair Wei Qing 卫青 and Huo Qubing 霍去病. Wei Qing was the illegitimate child of Wei Ao 卫媪 and Zheng Ji 郑季. Wei Ao was married to another man, and life was difficult enough for the family's existing children (Wei Ao already had one son and three daughters with her husband), so she sent Wei Qing to live with his father instead. However, Wei Qing's father made the young boy shepherd sheep, and the legitimate children in the Zheng family bullied him, ordering him around like a slave. Thus he decided to go back to his mother's family, and was employed as a stable boy by his mother's mistress (princess Pingyang 平阳公主).\n\nHuo Qubing was the son of Wei Qing's sister Wei Shao-er 卫少儿 and Huo Zhongru 霍仲孺. Huo Zhongru was fearful of acknowledging his son (most probably because Wei Shao-er was a serving lady to princess Pingyang, and he might be punished for being with her), and so Huo Qubing had to grow up being part of the servants in the princess' house. More fortunately for him, his auntie Wei Zifu 卫子夫 soon won the emperor's favour, and he was brought to court to be brought up and became a general at the age of 19.\n_____________\nThese information would only apply to sons, because sons were the ones who stood to inherit family estates. Taking your backstory into consideration, a daughter born to an upper class family would be reasonably well brought up as a lady, and would be married off at a suitable age to be a bride to a (hopefully) rich or powerful family. However, an illegitimate daughter would not be accepted into the family at all, and would have to live off whatever her mother's family could provide for her.\n\nIf her mother's family had enough money, she may still have a relatively easy life, but would not be permitted much freedom as it would be considered a family shame to let her be seen on the streets. She would also be married off as soon as possible to cut off her ties to the family.\n\nIf her mother's family did not have money to provide for her, she would probably be sold off - if fortunate, to a family that has no children and are looking to adopt; if unfortunate, to the brothel so that her mother could gain some quick cash. The family would not want to keep her, since an additional person means an additional mouth to fill.\n\nHopefully, these information helps out."
]
}
|
[] |
[] |
[
[]
] |
|
1klyog
|
how do physicists shoot beams of small particles, like electrons, protons, and neutrons?
|
On occasion, when reading about some experiment, say the dual slit experiment, I'll read that a beam of electrons are fired at the slits. How exactly does one do this? I'm assuming you can't just go out, buy some, and stick them in a gun.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1klyog/eli5_how_do_physicists_shoot_beams_of_small/
|
{
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"text": [
"Electrons are easy; they're the social butterflies of the subatomic realm. They flit about very promiscuously. And because they have electric charge, they're easy to manipulate with electric fields.\n\nThe general process by which electron beams are created involves passing an electric current (which is a flow of electrons, essentially) through some kind of conductor that, when it gets hot, sprays electrons out. This phenomenon is called *thermionic emission,* and it generally means that the *thermal* energy of the electrons exceeds the *binding* energy of the electrons, so they escape from whatever material you're using.\n\nOnce the electrons get sprayed out of the hot cathode, their trajectories are \"bent\" by the presence of electric fields. The spray is therefore shaped into a collimated beam.\n\nProton beams are a bit more complicated, because protons don't come flying off of hot things the way electrons do. Generally the way proton beams are created is by taking hydrogen gas — which is just protons with electrons clinging to them — and stripping off the electrons with a strong electric field. Electrons are very light particles compared to protons, so it's possible to yank them away and send the protons shooting off in the opposite direction. From there, it's the same story: Shape the spray of protons with electric fields to create a beam.\n\nNeutrons are even more complicated. They're electrically neutral, which means we can't touch them — literally. There's no way for you to accelerate a neutron. Instead, they have to be *made* by knocking hydrogen atoms together. Most hydrogen atoms contain just a single proton and a single electron, but some — called deuterium — have a neutron in there as well. If you smack two deuterium atoms together in the right way, they glomp together to make a helium atom, and eject the extra neutron. Do this in a very precise fashion, and you can create a beam of neutrons shooting out of a piece of metal. You can't control the beam the way you can with electrons or protons, because again, neutrons have no electric charge and can't be touched. But you get a beam nonetheless, which you can point at things to make a wide variety of interesting things happen.",
"Particles with an electric charge get accelerated when they enter an electric field, and get deflected when the enter a magnetic field. If you place the source in an electric field, all particles will get accelerated in one direction, creating a beam. \nYou can then use magnetic fields to force your particles onto certain trajectories (like a circle or a spiral). If you combine the two effects, you can build very sophisticated \"filters\" that only particles with a certain velocity can pass through, etc."
]
}
|
[] |
[] |
[
[],
[]
] |
|
ve8lx
|
Could a holographic monitor exist? Is it even possible?
|
To start, I'm not talking about the [pseudo-holographic chicanery](_URL_0_) found in the recent trend of [artist resurrection](_URL_3_).
I was staring at a [real hologram](_URL_2_) the other day, delicately picking up the pieces of my shattered psyche from the contemplation of how such an incredible illusion is achieved, when I found myself pondering the possibility of a kind of computer monitor which could not only display such an image from a digitally stored copy, but also show a succession of such images rapidly enough for animation to be achieved.
The closest I can find is [a full-colour hologram that animates as you walk by](_URL_1_).
Would this kind of monitor screen even be possible? If it were easily done I would assume it would exist already in some form. Is the only thing preventing this cost, or is there some physical rule of capturing and reconstructing these interference patterns that renders this concept impossible?
tl;dr Could hologram TVs exist?
|
askscience
|
http://www.reddit.com/r/askscience/comments/ve8lx/could_a_holographic_monitor_exist_is_it_even/
|
{
"a_id": [
"c53sls4"
],
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"text": [
"I can't remember what the technology is or called, sorry. But I remember recently reading about a system using very very small mirrors on micro electromechanical systems (MEMS) to create a real \"hologram\" (of the kind formed by the interference of light)\n\nHere we go: _URL_0_"
]
}
|
[] |
[
"http://en.wikipedia.org/wiki/Pepper's_ghost",
"http://youtu.be/MqRMktn-adM",
"http://en.wikipedia.org/wiki/Holography",
"http://youtu.be/TGbrFmPBV0Y"
] |
[
[
"http://spectrum.ieee.org/tech-talk/semiconductors/devices/spring-loaded-pixels-to-drive-holographic-displays/"
]
] |
|
3dg8r5
|
what is to be gained from this trip to pluto?
|
I haven't learned what the objective is.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3dg8r5/eli5_what_is_to_be_gained_from_this_trip_to_pluto/
|
{
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"text": [
"The objective is \"Curiosity\". If you're looking for a reason like Pluto is made up entirely of gold or vanilla ice cream, which is possible, than you're missing the point. The biggest point of all satellites is to sustain our appetite for curiosity. Humans are naturally curious, and exploring is in our genetic makeup as humans. Our pursuit of knowledge has begun since human has first existed and will continue until our last breath as a species. We are curious, what's out there in space, what do the other planets in our solar system look like, what are they made off, has there been any sign of other intelligent life form landing on the planet? The true objective is finding answers to questions we don't know, or don't understand...yet.",
"Consider from the perspective of before the mission was launched. There's a major body in the solar system, that everyone knows the name of, that we know almost nothing about besides what we can infer from its size and distance from the Sun and the general chemical composition of its surface. The best picture we have of it is [this](_URL_2_). \n\nThen you determine that for less than the price of one B-2 bomber ([New Horizons](_URL_1_)) ([B-2](_URL_0_)) you can find out what it looks like, get information about it that could potentially teach you more about how the solar system formed and evolved over time, help inspire a new generation of youths to pursue careers in science, feed everyone's curiosity, and display your country's technological prowess and economic strength (in a way that benefits society and isn't aggressive) by being the first and only to send a mission there. That seems like a no-brainer to me. Even if you don't get a tangible benefit like a new gadget or resources, it's still worth the tiny fraction of your country's yearly budget.",
"In truth is the same as what NASA wanted to find when they first went to the moon the knew there was nothing there and they didn't have anything to ask that they didn't know, the reason was to find things we don't know so a question is created and we can figure them out, "
]
}
|
[] |
[] |
[
[],
[
"https://en.wikipedia.org/wiki/Northrop_Grumman_B-2_Spirit",
"http://www.thefiscaltimes.com/2015/07/14/Here-s-What-It-Cost-Send-NASA-s-New-Horizons-Pluto",
"http://planetary-science.org/wp-content/uploads/2013/06/pluto-hubble-01.jpg"
],
[]
] |
|
1k5fz7
|
Baghdad was one of the biggest centers of learning of its time. Because of items like the Baghdad Battery recently being found, how advanced was this city before the Mongols burned it to the ground?
|
Was anything else similar to the Baghdad Battery recently found in excavations?
[Baghdad Battery](_URL_0_)
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1k5fz7/baghdad_was_one_of_the_biggest_centers_of/
|
{
"a_id": [
"cblpehj"
],
"score": [
3
],
"text": [
"I terms of macro technology, and the technology most people had access to Baghdad would have been about equal to most of the other cities around. Technology spreads quickly. It is likely that various things would have been more prevalent there because it was an extremely wealthy city as well as a trade and governmental center. But it is unlikely the city itself had many things that would not have been found elsewhere.\n\nI am not an expert in the Baghdad battery and as I understand it, the recent political upheavals have taken a serious toll on the amount of archaeology happening in the region."
]
}
|
[] |
[
"http://en.wikipedia.org/wiki/Baghdad_Battery"
] |
[
[]
] |
|
17akvw
|
What's the oldest prepared drink that could still be safely consumed? What's the oldest food?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/17akvw/whats_the_oldest_prepared_drink_that_could_still/
|
{
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"c83qmfl",
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"text": [
"The oldest food? 36,000 year old bison, if Dale Guthrie is to be believed (*Frozen Fauna of the Mammoth Steppe*, 1990). That is however an anomalous condition--fast-frozen in ice, and only a few morsels edible.\n\n[edit: and no, we have no reputable accounts of people actually eating unfrozen mammoth in recorded history.]",
"Oldest food? Honey wins out over every other known food. Edible (though crystallized) Honey has even been found in ancient tombs. \n\n_URL_0_"
]
}
|
[] |
[] |
[
[],
[
"http://ancientstandard.com/2011/05/16/the-sweet-history-of-honey/"
]
] |
||
5igdia
|
sound doesn't travel through space. it's a wavelength. light travels infinitely without degrading and it's a wavelength. what gives?
|
Sound needs a medium. I get that. Someone once explained if they spoke and increased the frequency, we'd hear sound, then microwave and radio frequency then eventually colors. Why do some frequencies propagate forever while others need a medium?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5igdia/eli5_sound_doesnt_travel_through_space_its_a/
|
{
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"text": [
" > we'd hear sound, then microwave and radio frequency then eventually colors\n\nThat was bullshit.\n\nSound is the vibration of a medium with non-zero mass.\n\nLight is transmitted by photons, massless particles.\n\nThem being waves is the only commonality between them.",
"Sound is a vibration carried by a medium.\n\nLight is carried by it's own particle, the photon.",
"Light is actually a particle that behaves, for the most part, like a wave. Photons of light are small packets of energy that are emitted from light sources. These photons travel as waves, that is to say, they have frequencies and wavelengths, which gives light different colours. Sound on the other hand is particles of air (or whatever medium the sound is passing through) creating high and low pressure areas that alternate between high and low, which creates the sound wave. When that pressure reaches your ear, your brain interprets that particular pressure as a sound. (Side note, that's why speakers move back and forth).\n\nTL;DR: Light is a particle that moves like a wave, which means that it can move through space.",
"Your mistake here is in thinking that radio waves are sound waves. They aren't. Radio waves are literally a different spectrum of light wave. It's only after a radio receives and converts them to sound via a speaker that sound is created. The speaker creates the compression through the medium (air). This is why radio waves can travel through space, and sound waves cannot.",
"So sound is the vibration of the air around you. When you slap your hand on a table, you shake the table, in turn shaking the air around the table, which in turn shakes your ear drum, and you process that as sound.\n\nLight in the other hand is a combination of electric waves permeating in the XY plane and magnetic waves permeating in the XZ plane, which tug and push on each other through the properties of electro-magnetism to traverse in the X direction. \n\nThis is radiation, not vibrations, and does not require a medium to travel through. This is because light pushes itself by the properties of what it is made of, so is self sustaining. Sound pushes OTHER THINGS and as such is not self sustaining. That is the fundamental difference between the two."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
|
118ihd
|
There's Planck Length, Planck Time, and Planck Temperature, each of which corresponds to a universal maximum of minimum(unless i am mistaken). Does this mean there can be such thing as a "Planck Number?"
|
Planck Length is the smallest length something can be. So a Planck number would be the largest (or smallest i guess) number that could ever exist. I know you can always add 1 but by that logic why can't we just subtract from Planck Length, or add to Planck Temperature? Cant there be a number so large that by adding 1 to it, it becomes something else? Or am i just being too abstract...
|
askscience
|
http://www.reddit.com/r/askscience/comments/118ihd/theres_planck_length_planck_time_and_planck/
|
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"text": [
"The Planck length/time/temperature/mass etc. are not the largest/smallest quantity you can write down, nor are they necessarily the largest/smallest quantity of that type that you can write down. What they represent is the scale at which one must pay attention to both quantum mechanics and general relativity (the Compton wavelength and Sqhwarzschild radius of a Planck mass particle are equal to each other), and thus a scale beyond which one will need a theory that harmonizes quantum mechanics and general relativity (a quantum gravity theory).\n\nNotice that these represent things with units, something about the scale of what is possible in the universe. Pure numbers are dimensionless, and so are a different kind of object to begin with. In addition, numbers are abstract quantities defined in the context of mathematics; the \"Planck quantities\" represent empirical features of the universe. We could, for example, imagine a universe in which the constants of nature had different values, thereby changing the Planck length; but changing those values won't change the number \"5\" to something else.\n\nHere's another example: There is some element that has the largest possible atomic number; let's be generous and just say that that number is under 200. That just tells us about nuclei and atoms; it doesn't tell us that numbers above 200 aren't meaningful.",
"I think this is a very good question. None of the \"Planck numbers\" are absolute. All of these measurements only represent limits of our understanding of physics.\n\nThe Planck length much smaller than anything we can currently measure. In string theory it's about the size of the vibrating strings which compose the most basic particles. In the theory of quantum gravity, anything less than a Planck length apart would appear to be in the same location (sort of a resolution limit of space).\n\nThe Planck time is just how long it takes for light to travel across the planck length. Since light is the fastest thing we know of, that's the smallest time we can imagine measuring.\n\nThe Planck temperature is a temperature so hot that gravity would play a significant role in how quantum particles behave--this is also something we don't know how to deal with yet.\n\nSo no there is no Planck number. One day discoveries could be made to expand the limit of these Planck values.\n\nIf you want to talk numbers...\n\nPlanck T = 10^32 Kelvin\n\nLifespan of a black hole the mass of the sun = [10^66 years](_URL_0_).\n\nOne can find physically relevant numbers that exceed these values.\n\nEDIT: I think the Planck temperature can be confusing to think about. Here's a [PBS article](_URL_1_) that should help.",
"No, there is no smallest or largest finite number. For any (large) finite number x, x + 1 > x . If you are talking about non-finite numbers, then first you need to refine the concept of number size.\n\nFor any small (I assume you mean \"close to but greater than zero\") number z, z / 2 < z.\n\nBy the way, /r/askmath exists.",
"**The answer you're looking for doesn't require any understanding of physics at all**, and certainly doesn't require an understanding of things like Schwarzschild radii or Compton wavelengths.\n\nAlthough the Planck units describe (what we believe to be) fundamental values, they *express* those values in *arbitrarily defined, human-invented units*. Planck temperature, for instance, can be expressed in Kelvin, degrees Fahrenheit, or any other unit of temperature you care to invent -- *and in each of those units, the number itself will be different.* You can even define a unit \"Planck temperatures\", abbreviated PT, in which the Planck temperature itself is expressed as \"exactly 1 PT\". You can see that the *number*, then, is arbitrary, and so it can't possibly have any special mathematical properties.\n\n**Nothing in physics can debar any particular number from representing a physically meaningful quantity, nor can it restrict what sort of mathematical operations can be done with that number.**"
]
}
|
[] |
[] |
[
[],
[
"http://en.wikipedia.org/wiki/Terasecond_and_longer",
"http://www.pbs.org/wgbh/nova/physics/absolute-hot.html"
],
[],
[]
] |
|
36cl0v
|
What strategic threat did Nazi Germany actually pose to the United States before December 7, 1941?
|
And what great strategic threat did a victorious Germany actually represent to United States interests that the US was willing to undertake a war across the Atlantic which it knew would be massively costly in blood and treasure?
For that matter, what reasons beyond benevolence did the United States have for aiding Britain and France with programs like Lend-Lease before its entrance into the war?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/36cl0v/what_strategic_threat_did_nazi_germany_actually/
|
{
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"crdxgpw"
],
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"text": [
"Hitler's immediate aim was dominance of the continent; however, once this had been achieved, it us unlikely that Germany would have tolerated the United States as a rival for 'weltmacht', or world power. Between the u-boat menace, the German naval plan Z, and other potential threats (ie Amerika Bomber project, German nuclear programme), even if the United States did not face an immediate threat, it was a threat that would rear it's *very* ugly head in the future. \n\nThere were also distinct fears that the Germans would attempt to influence Latin America, such as Juan Peron's Novo Estado in Argentina. There were various American war plans for intervention, in Brazil as one example, to head off Nazi attempts to carve out a sphere of influence.\n\nHence the lend lease program. By strengthening Germany's enemies, the united States could prevent the need for intervention, unlike in WWI. This proved not to be the case however, and involvement in a second, more terrible world war would be required.\n\nThat answer your question? "
]
}
|
[] |
[] |
[
[]
] |
|
6a90uz
|
Why do babies frequently wake up in the middle of the night?
|
askscience
|
https://www.reddit.com/r/askscience/comments/6a90uz/why_do_babies_frequently_wake_up_in_the_middle_of/
|
{
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"text": [
"We all wake up during the night. That is normal during certain sleep stages. Unlike infants, we have learned to go back to sleep. These waking moments are usually short and we forget about them afterwards, or we actually be awake and go to the toilet, etc. The 'half-awake' state can cause sleepwalking. You'll be fully awake, but not fully conscious. The opposite happens as well: you're fully conscious, but your body is still asleep. That is when we experience sleep paralysis.\n\nFor infants this is new. Everything new can be scary, because they lack the experience to deal with it. I once had to calm a crying child who was thirsty, but actually half asleep. I had to keep him standing up to drink, then 'walk' him back to his bed to continue his sleep.\n\nSmall humans are weird. ",
"Babies wake up frequently to eat. Their stomachs are tiny and a lot of metabolic processes occur during sleep, so they burn a lot of energy. Especially in the beginning, they'll wake up every couple hours out of hunger. ",
"Babies can't resolve errors on their own, like being too hot or too cold or hungry or thirsty. So when they wake up they need their needs to be met and they'll cry to make that happen. My daughter is 18 months old and we see her wake up frequently on her monitor. She's been sleep trained now though, and she has more capacity to meet her own needs, so she doesn't bother us. She sleeps in a flannel sleep sack with leg holes so she can adjust how much skin is exposed to get the right temperature, and she has a sippy cup of water and a book in her crib. Now, she'll typically wake up, roll around, sit up, have a little water, then lie down, roll a little and go back to sleep. This happens every hour or so. In the morning, she wakes up in a good mood most of the time.\n\nWhen she was a baby, she'd wake up and we'd have to take care of that kind of thing for her. The other factor is she can eat more at dinner than before so she doesn't wake herself in the night for food. That was a big one."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
5om0cw
|
How do we know about 1,700 planets?
|
How do we know about 1,700 planets in the Milky Way if Pluto is barely visible with a powerful telescope? How can we possibly see those planets if one in our solar system is barely visible?
|
askscience
|
https://www.reddit.com/r/askscience/comments/5om0cw/how_do_we_know_about_1700_planets/
|
{
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"dckclfy"
],
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"text": [
"Except in a [handful of cases](_URL_1_), we do not have direct images of those planets.\n\nRather, we detect the planets by their effects. Planets can be detected by slight changes in the wavelength of light of the host star; as the planet orbits the star, it pulls the star first one way and then the other, and due to the Doppler effect, this leads to a slight variation in the wavelengths of light we receive from the star. A second important method is the *transit method* (it is used by\nthe [Kepler mission](_URL_2_), for example). In this, scientists observe slight dips in the brightness of a star when a planet orbits in front of the star.\n\nYou can read about various other detection methods [here](_URL_0_)."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Methods_of_detecting_exoplanets",
"https://www.reddit.com/r/askscience/comments/44s6va/how_far_away_from_the_sun_do_you_have_to_be/",
"https://www.nasa.gov/mission_pages/kepler/overview/index.html"
]
] |
|
6i3x9n
|
how do the denotations of words change so much over time? like gay meaning happy but now homosexual, or faggot meaning bundle of sticks to a derogatory term for homosexual.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6i3x9n/eli5_how_do_the_denotations_of_words_change_so/
|
{
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],
"text": [
"[**Etymology of the word 'Gay'**](_URL_0_):\n\nIn the world's earliest meanings, going back to the 12th centry, it meant joyful, carefree, uninhibited, bright and showy, etc.\n\nBy the early 1800's, the word's implication of uninhibited pleasure had become euphemistically associated with immorality and lack of sexual inhibitions. Oxford dictionary at the time changed its definition of the word to include *\"addicted to pleasures and dissipations. Often euphemistically: Of loose and immoral life”.*\n\nThe word became associated with illicit sex and prostitution. A promiscuous man might be euphemistically called a \"gay lothario\"; a prostitute might be called a \"gay woman,\" a brothel called a \"gay house.\"\n\nBy the 1920's the euphemistic use of the word had started to shift from implying sexual promiscuity in general, to specifically gay sex when the word was applied to men. The ongoing association with \"bright and showy\" clothing also became associated with frivolity and femininity in men.\n\nBut at the same time, the word also continued to be used casually to just mean carefree or joyous. To call a man \"gay\" to imply he was homosexual was a bit like saying he was \"artistic\" in the same manner, or to say a woman was \"sporty\" to imply she was lesbian. There was no non-degrading term for homosexual at the time.\n\nIn the mid-50's, gay people had started to organize and develop a sense of group identity. Within these groups, there was a desire for a new word to identify themselves with that was neither a slur (\"sodomite\" and etc), nor pathologizing (\"homosexual\" was a psychiatric diagnosis of mental illness). For decades the word \"gay\" had been used among homosexual men as a non-insulting euphemism, so in the mid-50's this word was adopted as a direct term of identity.\n\nAfter Stonewall and the start of the modern gay rights movement in 1969, the use of the word \"gay\" to directly mean \"homosexual man\" (and later both men and women) became public knowledge. Which pretty much ended the casual use of the word to mean \"carefree.\"\n"
]
}
|
[] |
[] |
[
[
"http://www.todayifoundout.com/index.php/2010/02/how-gay-came-to-mean-homosexual/"
]
] |
||
350eha
|
Why did European explorers translate the titles of the rulers of China and Japan as "emperor" but translate titles of the rulers of other East Asian countries as "King"?
|
Also, I remember reading that European explorers compared the relationship between the shogun and the emperor of Japan as analogous to the pope and the holy roman emperor, with the pop being similar to the Japanese emperor and the shogun being similar to the HRE. If that's true, then why not translate shogun as emperor?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/350eha/why_did_european_explorers_translate_the_titles/
|
{
"a_id": [
"cqzwuqb"
],
"score": [
8
],
"text": [
"hi! not discouraging other responses, but you might get something out of these earlier threads\n\n* [Why the title of the Japanese monarch is translated as \"Emperor\", and the Thai monarch is called \"King\"?](_URL_2_)\n\n* [What is the difference between a king and an emperor? Why were there empires in Rome, Japan, and China, but kingdoms in Africa and Europe?](_URL_0_)\n\n* [Who were Emperors and who were Kings?](_URL_1_)"
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/2ygnra/what_is_the_difference_between_a_king_and_an/",
"https://www.reddit.com/r/AskHistorians/comments/27pk5z/who_were_emperors_and_who_were_kings/",
"https://www.reddit.com/r/AskHistorians/comments/2xz021/why_the_title_of_the_japanese_monarch_is/"
]
] |
|
e3coih
|
how can something made of mostly empty space be “sharp”?
|
Are certain atoms better at splitting molecules and does that equate to sharpness? Atoms bond differently to form different molecules but certain elements are easier to sharpen than others, so why does it matter if every atom is made of the same basic parts and mostly empty space? Is an edge 1 atom thick the ultimate expression of a point, or as sharp as an edge can become? What is being “cut”? Molecules?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/e3coih/eli5_how_can_something_made_of_mostly_empty_space/
|
{
"a_id": [
"f92adea",
"f92hfam",
"f92p5uq",
"f92uh2o",
"f93l2up"
],
"score": [
12,
3,
2,
2,
2
],
"text": [
"Imagine you took thousands of pingpong balls and superglued them together in to the shape of a knife blade, where the cutting edge has only one row of balls then gets progressively denser as it goes back.\n\nNow imagine you took a bunch more balls and glued them together in to a big block but only using rubber cement which is not nearly as strong.\n\nYou would be able to take that big pingpong knife and basically push it through the block that you made.",
"First: You identify \"solid\" with \"in physical contact\" while \"solid\" is actually \"with a strong magnetic field that makes it impossible to pass through\". What you see as empty space is as \"hard\" as the empty space between an object and the table it's resting on. \n\nSecond: A [sharp blade](_URL_0_) is on a much larger scale than atoms. \nA \"sharp shaped\" meteorite could cut a planet in two, even with an edge more blunt than a mountain range.",
"Sharpness isn't really a property of an atom. In general, \"sharpness\" is macroscopic, i.e. on a larger scale than atoms and molecules. Sharpness really is just about the shape of the object, or the organization of the atoms. Esentially you have a very thin edge on a knife that can still be several hundred atoms across. When you push a knife through something you separate the other object along a very thin line of stress, which causes it to cut cleanly. The properties of the atoms lend to the material of the knife, which affects how well the atoms can stay arranged in that \"sharp\" configuration.",
"You're misperceiving what \"atoms are mostly made of empty space\" implies. In our big-people world, there's \"stuff\", that you can touch and pushes back against your finger and you'll feel the contact and so on, and \"empty space\" that you can just move through. And you think this \"stuff\" is equivalent to the physics concept of \"things that have mass/energy\", and so when you hear \"an atom has a nucleus and electrons that have mass, but those are tiny and it's mostly empty space\" you picture yourself flying through that empty space with no resistance.\n\n & #x200B;\n\nBut the reality is, it's not *mass* that's resisting against your finger when you touch something. It's the *electromagnetic repulsion and attraction* between the electrons on that thing and your finger. Those electromagnetic forces make it *impossible* for atoms to just go through one another (quantum tunnelling aside, dunno about that), just like it's impossible for your hand to go through a block of concrete (and indeed, for the exact same reason since your hand and the concrete are made of said atoms; it's the repulsion between the electrons on the atoms of the concrete and your hand that are keeping one from going through the other. If you hand were a cloud of neutrinos it would go through fine).\n\n & #x200B;\n\nSo while it is accurate in a certain sense to say \"atoms are made of mostly empty space\", if we're using \"empty space\" to mean \"what an atom can freely move through\" then it would be just as accurate to say \"atoms are impenetrable balls\".",
"So in a way, is the act of cutting more or less a battle of electromagnetic forces than it is a separation of matter, if that makes sense? Would that mean that hardness is related to the amount of electromagnetic repulsion, enhanced by tighter/more efficiently configured molecules? Or am I completely off on thinking of sharpness or hardness in that sort of way? Thank you for providing such helpful information in your answer, unfortunately I have always struggled with the math side of things, so I have never taken a physics class. I’m sure much of this is rudimentary and basic lol"
]
}
|
[] |
[] |
[
[],
[
"https://i.pinimg.com/736x/f5/6e/2b/f56e2b17450468f4df412cc022aab886.jpg"
],
[],
[],
[]
] |
|
1bavtt
|
Why can't we see in colour in a dark room?
|
Looking around your bedroom at night when it's almost pitch-black you can still make out shapes, but everything seems to be monochrome. Why is this?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1bavtt/why_cant_we_see_in_colour_in_a_dark_room/
|
{
"a_id": [
"c95727b"
],
"score": [
23
],
"text": [
"Your retina has two types of cells: rods and cones. Cones see in colour, but their number is much smaller and they aren't very sensitive. Rods are much more numerous and sensitive, but they don't see colour.\n\nTherefore, when you're in the dark you only see with your rods: you can make out shapes that your cones would never pick up, but you lose the capacity to distinguish colour.\n\nOn a side note, rods are also responsible for peripheral vision. \n\n\n_URL_0_\n\n_URL_2_\n\n_URL_1_"
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Human_eye",
"http://en.wikipedia.org/wiki/Cone_cell",
"http://en.wikipedia.org/wiki/Rod_cell"
]
] |
|
1qvvds
|
Who would like to discuss Foucault to me?
|
Not exactly an historical question, so I hope it doesn't fall out of the mode too much, but as I am confronted with Foucault in some of my historical research, I would love to hear a variety of perspectives on discourse theory. Anyone up for a discussion?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1qvvds/who_would_like_to_discuss_foucault_to_me/
|
{
"a_id": [
"cdh2d9x"
],
"score": [
2
],
"text": [
"Interesting!\n\nFoucault essentially suggests that we can use history and 'genealogy' to study certain institutions of contemporary/modern society and that this can give us a sense of their true purpose. One claim is that there is a distinction between truth and appearances, though this is as ancient as philosophy itself. Another claim is that 'ways of thinking' can imprison people through their very worlds of possibilities. \n\nAt the heart of his work is a claim that the ways in which people make sense of 'true' or 'false' or 'correct' or 'wrong' or 'logical or 'illogical' is formed through certain historical and philosophical processes that ultimately result from political considerations that are arbitrary but appear legitimate, natural, and rational. He is not saying that we don't have truth in our world (penicillin works!). \n\nI think discourse theory is useful in understanding contemporary and modern societies. It is not the be all end all, but as with Descartes and Locke, Foucault provides tools which are uniquely suited for his society. \n"
]
}
|
[] |
[] |
[
[]
] |
|
38ms50
|
why don't our bodies have long term storage for air like we do with food?
|
I figure holding your breath is more analogous to holding food in your mouth. Why haven't humans adapted the ability to survive without oxygen for extended periods of time?
I feel like that'd be super useful.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/38ms50/eli5_why_dont_our_bodies_have_long_term_storage/
|
{
"a_id": [
"crw70hi"
],
"score": [
5
],
"text": [
"Humans very rarely are in situations where they don't have easy access to air. Humans were until recently often in situations where they didn't have easy access to food. Hence we evolved to store fat, and not air."
]
}
|
[] |
[] |
[
[]
] |
|
1re0dp
|
what would happen if i play a negative mold of a record?
|
I saw the music piracy post on the front page, and was intrigued. If I were to make a mold, of the record, and play that without filling the mold, what would happen?
P.S. If anyone is confused please, don't hesitate to ask for clarification!
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1re0dp/eli5_what_would_happen_if_i_play_a_negative_mold/
|
{
"a_id": [
"cdmap5t"
],
"score": [
3
],
"text": [
"The needle would ride in a large flat groove between two peaks that would make the groove on a record.\n\nIf you could play it, it would play from the end to the beginning because the groove would go in the opposite direction. \n\nAny sound you hear, besides the sound of the needle scratching on that flat space, would only be the left or the right because the needle can't touch both edges of a groove at the same time. It would also be backwards."
]
}
|
[] |
[] |
[
[]
] |
|
ajwr4y
|
the difference between amortization and depreciation
|
Can’t really wrap my head around this
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/ajwr4y/eli5_the_difference_between_amortization_and/
|
{
"a_id": [
"eeze7rt",
"eezeml8",
"eezpm3a"
],
"score": [
2,
3,
2
],
"text": [
"Amortization is an accounting technique used to lower the cost value of a finite-life or intangible asset incrementally through scheduled charges to income. Amortization is the paying off of debt with a fixed repayment schedule in regular installments over time like with a mortgage or a car loan.\n\nDepreciation is a reduction in the value of an asset with the passage of time, due in particular to wear and tear.\n\nSo, amortization is in reference to paying off debt with a certain fixed payment plan. So this is like a car loan or a mortgage. You pay $200 a month for 36 months and then it’s done, etc.\n\nDepreciation is the loss of value over time. \n\nAmortization is the gradual reduction of debt over a given period.\n\n\nI don’t really see how they are related though? What else do you mean by your question?",
"If you're wondering which would be applied to something, depreciation is for things that physically wear out, like machinery, while amortization is for things that don't physically wear out, but eventually expire, like a patent.",
"Amortization is used in two ways. \n\nLoan repayments - When you make a loan payment, there are two parts to it, one is the principal reduction and the other the interest charge. The principal reduction is an amortization of the original loan debt.\n\nAmortization is also used to reduce the value of **intangible** assets. You can amortize a previously capitalized R & D cost or amortize an expensive piece of software etc. This basically means you are taking an expense against the original value of that asset to show it is worth less over time.\n\nDepreciation is a similar concept used for **tangible** assets. Again, it is a charge taken periodically to reduce the value of the asset in order to recognize that is less valuable over time. Eg. cars, equipment. In some cases, there may be \"rules\" in GAAP that specify how certain assets can be depreciated - but generally it is possible to pick what is believed to be suitable. \n\nSince both amortization and depreciation are non-cash charges (i.e. you're not really paying anyone) it has the impact of reducing net profit without impacting cash flow. This has a benefit for income tax purposes but may also make it look like a company isn't making much profit even though it is cash flow positive.\n\nMost companies (public) will publish a figure called EBITDA - earnings before interest, tax, depreciation and amortization. This gives you a better sense of the \"operational performance\" of the company. \n\n & #x200B;"
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
vvlcz
|
Why didn't the indigenous Australian's have domesticated animals? Especially dogs?
|
It's my understanding that dingoes are descendants of the domesticated dogs the pre-aborigine people brought with them when populating the continent. Why would they give up so advantageous an animal even with a hunter-gatherer lifestyle?
Bit of a side question, why would they also have not attempted to domesticate any other animal? Even regular wombats or possums could have been bred to be excellent sources of fur/meat/milk etc. could they not?
(My only knowledge of this is that picked up from Guns, Germs and Steel as well as living in Australia my entire life)
|
askscience
|
http://www.reddit.com/r/askscience/comments/vvlcz/why_didnt_the_indigenous_australians_have/
|
{
"a_id": [
"c580b1h",
"c583h51"
],
"score": [
2,
2
],
"text": [
"They did. Not dogs because dogs aren't native to Australia but we used to have similar animals called dingos, which have been bred with dogs to the extent there are no pure breed dingos left, which were domesticated by the Aboriginals.\n\nAs for the other animals, the Aboriginals were a nomadic people and I imagine that carrying or waiting for a wombat or possum to follow you was not an appealing option when the place you're going to is going to have both that you can kill and eat without waiting around for them to follow you.",
" Theres a great book that was part of the education curriculum at one point called \"Last of the Nomads\". In that book the aboriginal couple had close relationship with dingoes. It was quite sad that when the couple were saved or removed from the desert during drought the dingoes would die from lack of water. As the couple dug up ground water for the dingoes to drink.\n_URL_0_\n_URL_1_"
]
}
|
[] |
[] |
[
[],
[
"http://aso.gov.au/titles/documentaries/the-last-of-the-nomads/clip1/?nojs",
"http://www.wadingo.com/Dingoes_and_Aborigines.html"
]
] |
|
2bycgj
|
why do some porn sites not need 18+ proof, but some do?
|
Some porn sites need proof of being 18, but other sites need no proof.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2bycgj/eli5_why_do_some_porn_sites_not_need_18_proof_but/
|
{
"a_id": [
"cja3pfc"
],
"score": [
3
],
"text": [
"perhaps the one that needs no proof isn't operating in the US or a country that requires proof of age"
]
}
|
[] |
[] |
[
[]
] |
|
3n577p
|
In the Game of Thrones TV series (and book) bastards from different regions all share a common surname to identify them, Snow or Flowers for example. Does this system have any evidence in history or was it invented by the author?
|
Thank you.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3n577p/in_the_game_of_thrones_tv_series_and_book/
|
{
"a_id": [
"cvkwodh",
"cvlkk1c",
"cvlo251"
],
"score": [
91,
10,
12
],
"text": [
"Responses covering more regions/cultures of Medieval Europe are welcome; meanwhile you may be interested in these\n\n* [Bastard names](_URL_0_)\n\n* [During the Middle Ages and the Renaissance, how was the surname of illegitimate children determined?](_URL_1_)",
"There's a sports reporter called Dan LeBatard and I've always wondered if his ancestor was a Bastard. Does anyone know anything about this name?",
"In Denmark-Norway there was a tradition in the 1500s-1600s to name the illegitimate sons and daughters of the king Gyldenløve (literal translation to english would be \"Golden Lion\".\n\nChristian IV, Frederik III and Christian V of Denmark all had several children by various mistresses who all carried the surname Gyldenløve.\n\nSo at least for Danish royalty there at one time was a \"system\" of naming bastards if you will."
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/2uzngr/bastard_names/",
"https://www.reddit.com/r/AskHistorians/comments/1rt40t/during_the_middle_ages_and_the_renaissance_how/"
],
[],
[]
] |
|
23e4ur
|
When was music viewed as a popular way of protesting government actions?
|
For example, War Pigs by Black Sabbath, and Ohio by Neil Young, being written as songs protesting wars/acts of aggression by governments. Was music always viewed in this sort of way, or was there a certain time period where people decided to start using music as expression a distaste for government actions (I.E laws, wars, hostile acts, etc?) Sorry if I'm not clear enough in my wording
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/23e4ur/when_was_music_viewed_as_a_popular_way_of/
|
{
"a_id": [
"cgw3qdh"
],
"score": [
2
],
"text": [
"One of the first instances I can think of is the [Carmina Burana](_URL_1_) - no, not Carl Orff's 1936 work, but rather the 11th and 12th century text that he drew his lyrics from. The Carmina Burana contains songs by the Goliards, a sect of the clergy who we see were very critical of the Catholic Church, particularly in their abuse of simony and penchant for greed.\n\nA more mainstream example that comes to mind is probably the emergence of [opera buffa](_URL_0_) (comic opera) in the early 18th century. Because the intended audience of opera buffa was the middle classes (as opposed to opera seria, which was created largely for the aristocracy and royalty), librettists (story writers) often strongly satirized political conditions of the day. Since the scathing, lightly veiled commentary was couched in music, humor, and costumes, the underlying message was able to slip past typical censorship and into the mainstream."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Opera_buffa",
"http://en.wikipedia.org/wiki/Carmina_Burana"
]
] |
|
excbir
|
how does a bread making machine work?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/excbir/eli5_how_does_a_bread_making_machine_work/
|
{
"a_id": [
"fg7gr3v",
"fg7ia3h"
],
"score": [
3,
2
],
"text": [
"It automates the process of kneading (by mashing the ingredients with a rotating paddle, usually) then lets the dough sit (and beeps at you to remove the paddle so it doesn't get stuck), then bakes it.",
"Making bread is not that complicated. You take flour, water, salt and yeast and knead them together to make a dough. You allow the dough to rise and then you apply heat to bake the dough into bread.\n\nA bread making machine does exactly that. It's basically a bucket with some rotating paddles. You put the ingredients in and the machine will mix the ingredients, knead the dough, allow it to rise and then bake it into a bread."
]
}
|
[] |
[] |
[
[],
[]
] |
||
427mp1
|
The Roman Republic and Greek(Athenian) Democracy are traditionally dated to 509 BC and 508 BC respectively. Is this a coincidence or could they have possibly drawn inspiration from the same root cause?
|
First off, I would like to say that my knowledge of history consists of a bunch of Wikipedia binging at work so please correct me if I'm wrong in my dates. That being said, I always found it extremely coincidental that Greek Democracy and the Roman Republic were founded within a year of each other. I know each respective culture has it's own explanation for over throwing a tyrant king and subsequent formation of the new government. However, Greek trade with Italy as far as I know was occurring at this time and I'm sure they were exchanging/discussing ideas on government. Is there a possibility that the Romans influenced the Greeks or vis versa regarding the development of their respective governments?Could they both have possibly developed the idea of meritocracy from the same root cause?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/427mp1/the_roman_republic_and_greekathenian_democracy/
|
{
"a_id": [
"cz8ext8"
],
"score": [
30
],
"text": [
"It's not a coincidence at all, but not for the reason that you think. The traditional date if the expulsion of the Tarquins *must* be a later tradition attempting to imitate the Athenian one. That Rome had kings and that some of these kings were probably Etruscan is pretty certain, but the precise dating of the expulsion of the kings and the exact events as described by later sources like Dionysius of Halicarnassus and of course Livy are certainly an invention. The expulsion of the kings by two leaders, one of whom is incited by sexual assault (Collatinus for the Tarquins and Harmodius for the Pisistratids) against a female relative by a younger relative of the tyrant (Lucretia by Sextus Tarquin or Harmodius' sister by Hipparchus) is simply too obviously an imitation of the Athenian story to be accurate, and generally scholars dismiss the story as it is presented. I mean, for Christ's sake the Tarquins were expelled in exactly the same year as the Pisistratids, 510. This isn't the only time when we see obvious attempts to link the pre-Republican or earliest Republican traditions with Greek traditions of about the same period. Stories like Horatius Cocles and the sacrifice of the 300 Fabii are both quite obviously influenced by the defense of Thermopylae. These stories probably are based on something real (obviously the expulsion of the Tarquins is based on something that actually happened, as the kingship at Rome ended after all) or at least are based on older native traditions, but the Greek influence of obvious and very much there"
]
}
|
[] |
[] |
[
[]
] |
|
1ne3hs
|
Did the Mongols leave any long-term institutional or cultural legacy in the places they conquered?
|
There's a lot of talk about how Alexander hellenized the places he conquered. Did the Mongols have a similar effect?
Edit: What I mean is peoples becoming more like the mongols not unintended consequences of their rule.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1ne3hs/did_the_mongols_leave_any_longterm_institutional/
|
{
"a_id": [
"cchsdb3",
"cchu7x3",
"cchyznp"
],
"score": [
7,
7,
2
],
"text": [
"one point of reference: in his book \"Russia and the Golden Horde\", Halperin concludes that while the Mongols had a traumatic effect on the Russians, they left surprisingly few traces of their culture or language, considering that they were the overlords of Russia for centuries. the Russians had to pay their taxes and toe certain lines, but their main interaction with the Mongols was paying taxes or tributes or being raided as punishment for disobedience. at least that's how Halperin tells it. he did note details on legacies when they came up, maybe aspects of court etiquette, but i can't remember.. i'll look it up if no one else knows.\n\nand I don't have a particular source on it, but I've read many times the claim that the Mongols had similarly little effect on China - their interaction with the populace was focused on extraction and security, aspects in which they were completely replaced when they were driven out of the country.",
"Jack Weatherford in his work : \" Genghis Khan and the Making of the Modern World\" outlines that the Khan and his Horde spread policies of religious tolerance to every region they conquered. While this would not be a long standing practice after the fall of the Mongol Empire, it was a piece of Mongol Culture carried to the realms it touched during their period of imperial influence.",
"In Rene Grousset's Empire of the Steppes, Rene points to the mongolian conquest of Russia being the first step in the nationalization of Russia away from principalities. Moscow benefited greatly from this because they got special treatment from the Mongols for one reason or another. Kiev, the historically greatest city of Rus. When the Mongols sacked Kiev, something like 2,000 people survived from a population of 60,000. This happened across Rus and Moscow capitalized with trade and became a rich city. So when the Mongol military might weakened, Ivan IV (the terrible) capitalized by defeating the remnants and taking over basically the modern day borders of Russia as we know it. This likely would not have happened without centuries of Mongol rule as Muscovite's are ethnically nothing like people across the Urals, so it was the Mongolians that first brought a sense of nationality to Russians."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
6i2ajp
|
in mmos, what stops a game from having large scale battles?
|
The large scale battles in real life never consisted of a mere few thousand people but often hundreds of thousands to millions of people.
ATTOTP (at the time of this post) there are 439,688 actively playing ff14. A game like this has enough players to have a large scale battle as seen in history. What in technology stops this from being possible?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6i2ajp/eli5_in_mmos_what_stops_a_game_from_having_large/
|
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"Technology.\n\n\nLarge battles require lots of network battle and actions from the game engines. Animating that much on a large scale is difficult as well even with 3d technology.\n\n",
"For starters everyone's pc would have to be capable of rendering that many characters in one spot, as well as register all the actions made by those characters. But I would imagine there would be a lot of stress on the servers having everyone in spot.",
"Rendering and communication of actions. [This is a good example of a massive number of players doing battle](_URL_0_). A thing to note of this is that in real time it took 21 hours, in actual play time it was about 2 hours. TiDi is explained at the bottom of that link. \n\nThe tldr, is that with the number of players connected in one spot, you over load what the servers can render, keeping track of everyones actions and effectively communicating that to every player takes a lot of power. What it comes down to is that no one actually runs that much hardware, and even more importantly, no one has the software to handle that much information in that way. "
]
}
|
[] |
[] |
[
[],
[],
[
"https://community.eveonline.com/news/dev-blogs/the-bloodbath-of-b-r5rb/"
]
] |
|
hem8k
|
What percentage of the human genome defines our body and what percentage defines our brain?
|
I'm thinking of human DNA as a software program, how many lines of code are there for each part? What's the most complex part of humanity genetically speaking?
I understand some of the data may be "compressed", but still...
**edit:** Thanks for the answers everyone. I'll try to summarize the answers, but there's a lot of stuff here that needs to be read very specifically. Reading all the comments is highly recommended.
* DNA doesn't work that way. E.g. a possible answer is 90% body, 90% brain.
* Sets of genes are influenced by the surrounding sets of genes being turned on and off. And it is not just a binary "on/off" scenario, there are gradients, combinatorial effects, and probably other modes of contol.
* DNA is more like a recipe for baking cake than a blueprint for building a house.
|
askscience
|
http://www.reddit.com/r/askscience/comments/hem8k/what_percentage_of_the_human_genome_defines_our/
|
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"text": [
"that is not how it works. many of the areas of the genome which code for \"body\" also code for brain structure.",
"To give a rough idea of the actual proprtion of brain-important DNA/ non brain-important DNA (important meaning not essential for forming the brain, but required for correct functioning), consider that almost any cytogenetically visible deletion of DNA (which may be ~1% of the genome - could be more, could be less, will also have other effects) will produce a phenotype with some degree of mental retardation, usually towards the severe end of the scale, as a result of the loss of genes with some kind of 'brain defining' function. Deletions of particular regions will cause specific syndromes with distinct phenotypic abnormalites, but mental retardation is practically a constant. \n\n",
"This is not a good way to think of DNA - generally speaking, there is an embryonic development phase, a growth phase, and a maintenance phase in humans. You cannot really separate one from the other, and even in each particular phase there is often no such clear distinction in roles - there is no \"brain\" gene. I mean, there are some genes that clearly function in the CNS only, but a better bi-phase separation of all our genes, instead of \"brain\" and \"body\", would probably be \"CNS\" and \"not CNS\".\n\nIt's like asking what percentage of a car is involved in going, and what percentage of a car is involved in stopping. Some things, like the accelerator and brakes, are clearly involved only in one aspect. Then what about the wheels? They're clearly involved in both, in a way. What about the body? Without the car body, the whole question is meaningless. And what about something extraneous, like the radio antenna? This is why I'm saying that you're better off categorizing car parts as \"involved in moving\" and \"not involved in moving\" - and even then it's still kind of a weird way to think of a car's parts.\n\nWhat actually happens is that from a single diploid cell, through many regulatory steps, forms a tube structure. From that, we get our head, limbs, and trunk structures. Somewhere in that process the central nervous system (which includes the spinal cord) develops alongside all these steps - the process is called [neurulation](_URL_1_).\n\nA family of proteins containing the [homeobox](_URL_0_) domain are important in this step, as well as the Wnt/[Sonic hedgehog](_URL_2_) protein network. I think these are along the lines of what you're looking for, but to answer your question, if you're going to think of DNA as a software program, you have to rethink how you're categorizing the parts of the end product (the human). If you do brain/body then the premise won't make much sense, much like asking what percentage of code for a game encodes for the top half of the screen, and what percentage of code encodes for the bottom half of the screen."
]
}
|
[] |
[] |
[
[],
[],
[
"http://en.wikipedia.org/wiki/Hox_genes",
"http://en.wikipedia.org/wiki/Neurulation",
"http://en.wikipedia.org/wiki/Sonic_Hedgehog#Patterning_of_the_central_nervous_system"
]
] |
|
9l2xeu
|
How are space probes like Cassini protected from colliding with asteroids and space scrap?
|
askscience
|
https://www.reddit.com/r/askscience/comments/9l2xeu/how_are_space_probes_like_cassini_protected_from/
|
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"There really isn't much in space, it's not like the movies. For example when we say \"asteroid field\", we mean that there is a 1km or larger asteroid every 2million miles or so, which is further than the distance from the earth to the moon. [Source is stackexchange](_URL_0_) but it's simple math.\n\nThe odds of a satellite hitting anything in space is so astronomically low that it's not worth doing anything about it. You really need to try if you want to hit anything.",
"They aren't, at least on a macroscopic level. The asteroid belt is so sparse that it's not even a consideration when sending progress to Jupiter and beyond. At microscopic scales it really depends on where the probe is going. The proves that have made close encounters with comets have used \"Wipple Shields\" when passing close to the comets. These are layered piles of Kevlar and other materials that basically act like a ballistic vest in the direction of travel.\n\nCassini is an interesting case. During the initial dive of the proximal orbits that eventually lead to is destruction, it was oriented so that the main antenna was in the direction of travel. (This was during its first dives between the rings and the planet). This would cause the main antenna to serve as a shield of sorts to protect the body of the probe. When it was discovered that part of space was much emptier then was originally thought, they ran later missions in other orientations so they could do radio Science on the rings.\n\nThe biggest issue, though is radiation and the damage it causes. Juno, currently in orbit around Jupiter, had its electronics inside a titanium vault that helps to shield them from the intense radiation caused by Jupiter's magnetic field.",
"Everything in space travels in elliptical orbits (following [Kepler's laws](_URL_1_)) and NASA maintains a rigorous database of where most stuff is. (There is a software called [STK](_URL_0_) that you can use to load and view the data set, although I cannot find the data set at this moment and STK takes some pretty rigorous computational power) So between these two things, there isn't a lot of randomness in terms of where stuff is (over the course of the billions of years of our solar system, almost everything has been pulled together gravitationally so stuff moves in clusters; think planets and moons or the Kuiper belt).\n\nSpace probes are then also moving in elliptical orbits (I think Voyager I is traveling in an escape orbit from the sun, which is different mathematically in terms of time predictions but is still a type of ellipsis), which are similarly predictable. So they aren't protected from collisions so much as able to avoid them in the first place.\n\n & #x200B;\n\nAs more and more satellites go up around earth, this has become increasingly concerning because everything needs to go through the LEO layer (where most stuff gets ditched) and collisions can be devastating there because things tend to have a lot of momentum."
]
}
|
[] |
[] |
[
[
"https://physics.stackexchange.com/questions/26712/what-is-the-average-distance-between-objects-in-our-asteroid-belt"
],
[],
[
"https://www.agi.com/products/engineering-tools",
"http://hyperphysics.phy-astr.gsu.edu/hbase/kepler.html"
]
] |
||
1c75lz
|
How does the body maintain itself without correct nutrients? (example inside)
|
askscience
|
http://www.reddit.com/r/askscience/comments/1c75lz/how_does_the_body_maintain_itself_without_correct/
|
{
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"c9doi6c"
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"text": [
"She doesn't, and that causes all kinds of problems. Quoting the article you linked\n\n\"Readman could not be reached for comment but according to her doctors, she is malnourished and has the health of an 80 year old. \n\n\"That sounds like an accurate assessment,\" says Lisa Kaufman, a pediatrician at Village Pediatrics who has not treated Readman. \"A diet of instant noodles has likely wreaked incredible amounts of havoc on her organs. The body—especially one that's still developing—needs protein, minerals, and nutrients to grow; that's just basic common sense. Without it, this girl has probably suffered stunted growth and IQ, osteoporosis, heart and kidney damage, and high blood pressure. Her lifespan has likely been shortened as well.\" \n"
]
}
|
[] |
[] |
[
[]
] |
||
3747g1
|
What's the best source to obtain scientific papers regarding a particular subject?
|
askscience
|
http://www.reddit.com/r/askscience/comments/3747g1/whats_the_best_source_to_obtain_scientific_papers/
|
{
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],
"score": [
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"text": [
"In physics, math and astronomy, the [arXiv](_URL_0_) is a free pre-print server you can use. When scientists in these fields write papers that become accepted for publication, they often post their papers on this archive. All papers are free access, so you don't need to worry about being trapped behind a paywall."
]
}
|
[] |
[] |
[
[
"http://arxiv.org/"
]
] |
||
6v7x16
|
what is nat and what does it do / what is static nat?
|
What is NAT - what exactly does it do? And what is a static NAT and what does that do? Tried looking it up but the definitions weren't very eli5-friendly.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6v7x16/eli5what_is_nat_and_what_does_it_do_what_is/
|
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"text": [
"You have a single Internet connection, and you only get a single address from your Internet Service Provider, but you have multiple devices that you want to connect to the Internet- your laptop, your phone, your game console, and so on.\n\n One way to connect multiple devices through a single connection is Network Address Translation, or NAT. You have a single device (your router) connected to the public Internet, and the rest of the devices are connected to a private network. When each of your devices wants to communicate across the Internet, they send messages to your router and your router relays the information to the destination, making all the traffic look like it comes from that one public facing Internet connection. Your router keeps track of which device was communicating with which server so when the responses come back, it knows which device to send it to. \n\nThis works fine for sending traffic, but with only one IP address connected to your router, none of your devices other than that router are publicly accessible from the outside Internet. So if you want to run a server (whether it's a website or a game server) on one of your devices, there's no direct way for people outside your network to send requests to your computer. Static NAT is a way of setting up your network so that your router forwards the requests it receives to a specific computer within your network. That way, your computer inside the private network can receive requests from the greater Internet.",
"NAT basically translates a device ip adress to another address. This is usually so that the device can talk to the internet. Inside your home there are multiple ip addresses (your phone, your computer, your fridge maybe) but these can only talk within your home. When you need to talk to the internet your router will translate those devices to an ip address that can actually talk to other internet ip addresses.\n\nThere's more applications than just that but that would be the general, eli5 gist.",
"NAT - Network Address Translation.\n\nYou live in a private home. Your devices connect to a private address called a LAN, a Local Area Network. Even if you have routers, switches and other devices, without a device to connect you to a WAN, Wide Area Network, you will only ever see your devices and never out to the internet.\n\nYou live in a city, in a state, in a larger world. Every home has its own \"private network\". So to help reduce strain on the ISPs that connect the world together, a NAT solution was devised.\n\nNAT, takes your private network, and assigns an address to your private address' gateway called a Public IP.\n\nThink of it like your home. You have a Living room, a Bedroom, a Bathroom, and a Kitchen. That's 4 addresses. Everyone else in the world also has these as well. So sending information to each one with it's own address would be tedious, time consuming, and redundant.\n\nSo, your LAN is made up of all the rooms in your home and your Private network is established. Your public network, is the Post office box outside your home. This is the access point that links the WAN to your personal LAN.\n\nSo in computer terms:\n\n* Your computer is assigned a network address of 192.168.0.20.\n* Your mother's computer is also assigned a network address of 192.168.0.20.\n* Both of your computers talk to a Gateway who's address is 192.168.0.1.\n* Your Gateways are assigned their own \"public\" IP addresses. Yours is 24.24.25.25 and your mothers is 7.7.9.8.\n* With this setup, your Gateways will search and find the other's Public IP address and trade information when you email Eachother, but the local Private addresses stay the same.\n\n"
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
4xlv9x
|
why are distance runners so skinny?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4xlv9x/eli5_why_are_distance_runners_so_skinny/
|
{
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"d6gim32"
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"text": [
"The more you weigh, the more work you have to do to move yourself over a long distance. Sprinters need to be muscular since short distance events are more about accelerating to your top speed quickly and maintaining that speed for a few seconds while distance events are about maintaining a moderate (but still very fast) pace for anywhere from 14-15 minutes for a 5k to just over 2 hours for a marathon."
]
}
|
[] |
[] |
[
[]
] |
||
65jgod
|
why did canada get rid of the penny?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/65jgod/eli5_why_did_canada_get_rid_of_the_penny/
|
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"text": [
"Because it's not necessary, and stopping the manufacture and distribution saved the Crown a lot of money. We just round prices up or down after tax, and it balances out in the end.",
"Canada got rid of the penny because the penny costs more to make than it's worth. \n\nA good video: [Canada gets rid of the penny](_URL_0_)\n\nEdit: put in the right link",
"The same reason we've gotten rid of the half-penny, it's become an essentially worthless amount of currency in day-to-day transactions and additionally costs more to create than it's worth.",
"The cost of production is a bit of a red herring. A coin can be used thousands of times and each time it gets used it is still worth a penny, so divide the cost of production by how many times the penny is used to get a more realistic figure. \nThe biggest reason is that the penny had so little buying power that it was not worth carrying them around and using them to pay for things. It had become basically a *one way coin* in that it was given as change to purchasers and then either discarded or tossed in a jar somewhere and forgotten about. \n So basically the penny was no longer used as a means of payment by just about everyone except that person in front of me at the express checkout. \n\n"
]
}
|
[] |
[] |
[
[],
[
"https://youtu.be/nU4E6SSy5Yg"
],
[],
[]
] |
||
1605bz
|
i hope everyone here knows about the simple english wikipedia (url in text)
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1605bz/i_hope_everyone_here_knows_about_the_simple/
|
{
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"c7rfueo"
],
"score": [
2
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"text": [
"This is amazing! My brother will love this!"
]
}
|
[] |
[] |
[
[]
] |
||
3k0sp3
|
Isn't it an evolutionary advantage for a living disease not to be fatal to us?
|
Say you have bacterium x that causes a disease. Here are two scenarios;
1. Disease x is non-fatal. The carrier lives longer, comes into contact with more people, the disease travels to more New hosts. As it is non-fatal, there is no significant attempt to cure it.
2. Disease x is fatal. People die soon after contracting it. In that time, they meet fewer people. Fewer people contract disease x, so it's worse at spreading. As it's fatal, there is a mass effort to cure it. Disease x is eventually cured and the bacteria are no longer successful in humans.
Surely scenario 1, I which a disease is non-fatal, is better, and surely there should be an evolutionary push towards it? Isn't being fatal to its host a massive evolutionary disadvantage, particularly when the hosts have invented medical science and are liable to find a cure?
|
askscience
|
https://www.reddit.com/r/askscience/comments/3k0sp3/isnt_it_an_evolutionary_advantage_for_a_living/
|
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"text": [
"Not necessarily, though logically you would think so since it makes all kinds of sense. While some viruses or other diseases do evolve toward lower lethality, it appears to be more of a special occurrence, rather than the rule. Take the [rabies virus](_URL_3_), for instance. It causes a disease which is almost invariably fatal. Until the [Milwaukee protocol](_URL_5_) was introduced in 2004, no one had been recorded to survive rabies exposure without receiving the vaccine in time, however attempts to replicate the Milwaukee protocol have since failed, but extended the patients' lifetimes by around 30 days as /u/AGreatWind mentioned below. In essence, it was about 100% fatal in humans (not in all animals, however), and yet [is believed to have been around for about 1500 years](_URL_6_), giving it plenty of time to develop reduced virulence if it was going to.\n\nIn the 1950s, a poxvirus known as [myxoma virus](_URL_1_), normally spread by mosquitoes or fleas, was released as a biological control measure against an exploding European rabbit (*Oryctolagus cuniculus*) population, which had been introduced in Australia in the 1800s. Myxoma virus's native host is the South American rabbit *Sylvilagus brasiliensis*, in which it causes only mild virulence. In European rabbits however, it causes a disease known as [myxomatosis](_URL_2_), and is highly lethal. The original strain released into the European rabbit population in Australia was known as Standard Laboratory Strain, or SLS (super original, I know), and was phenomenally lethal - approximately 99.8% of rabbits infected with it died, usually within 14 days. A population of over 600 million rabbits was reduced by 85% to around 100 million, before the rabbit population began to rebound. \n\n[Here is an excellent discussion piece on the evolution of viral virulence](_URL_0_). To summarize however, the rabbits experienced a strong selective pressure for alleles conferring protection to the disease, as the mortality of immunologically naive European rabbits in Australia exposed to SLS decreased from > 90% to < 50% in only a few generations, and eventually dropped even lower. At the same time however, the virus itself diverged into a number of different circulating strains (all of which have been shown to have diverged from SLS) with reduced mortality. Eventually though, below a certain limit (approximately 50% mortality), the virus was no longer able to spread efficiently, presumably because the viral titer in the skin (where mosquitoes or fleas would bite) was not high enough to survive the transfer to the next host. As such, the virus evolved toward *moderate* lethality, rather than a state of *a*virulence. \n\nSo while it would seem to make sense that a disease would want to develop some sort of non-fatal infection, it is usually not the case. Instead, viruses tend evolve toward enhanced *transmission*, which can come about through decreased or even increased mortality. [I highly recommend reading the aforementioned link](_URL_0_) for a more thorough explanation on disease evolution, as this applies to more than just viruses. Additionally, the same blog has [another excellent post on how the rabbits themselves evolved toward enhanced resistance to myxoma virus](_URL_4_), if you are interested in learning more about it.",
"Also, pathogens that are fatal to people typically thrive in another host. So, they evolved quite well to co-exist with another host, and the fact that they are lethal to people is just a coincidence — a coincidence that we tend to interpret as significant when we forget we, as a species, aren't really a big deal.",
"As with all things in evolutionary biology, you have to weigh the trade-offs to determine an evolutionarily stable strategy - and there may be multiple optima. For example, cholera is a highly virulent disease. While it kills its host relatively quickly, it is also transmitted very easily - through contaminated water/fluids. So in the short time between infection and death, the host has already spread a lot of the bacteria around in feces, etc. such that the bacteria have already \"reproduced\" in the evolutionary sense. Because of this facile route of transmission, the optimum for cholera seems to be closer to highly transmissible/highly fatal than non-fatal. \n\nBerkeley does a good job explaining it for the lay reader if you're interested. \n\n_URL_0_",
"A large portion of the diseases fatal to humans are transmitted through contact with animals. The disease usually isn't fatal to the animal host, but is to humans.\n\nEbola comes from fruit bats. \nBubonic plague from fleas. \nAvian flu from birds. \netc... \n\nThe increase of the human population increases chances of contact with wild animals and increases the potential to spread lethal diseases."
]
}
|
[] |
[] |
[
[
"http://www.iayork.com/MysteryRays/2007/08/26/rabbits-1-virus-1-evolution-of-viral-virulence/",
"https://en.wikipedia.org/wiki/Myxoma_virus",
"https://en.wikipedia.org/wiki/Myxomatosis",
"https://en.wikipedia.org/wiki/Rabies_virus",
"http://www.iayork.com/MysteryRays/2008/03/02/hostvirus-co-evolution/",
"https://en.wikipedia.org/wiki/Milwaukee_protocol",
"http://www.sciencedirect.com/science/article/pii/B9780123870407000111"
],
[],
[
"http://evolution.berkeley.edu/evolibrary/news/071201_adenovirus"
],
[]
] |
|
ephz2a
|
why does it feel good to talk badly about someone who’s wronged us?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/ephz2a/eli5_why_does_it_feel_good_to_talk_badly_about/
|
{
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"score": [
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],
"text": [
"When we talk badly about someone who’s wronged us, we are contrasting their behavior to ours; making us feel entirely separated from ‘wrong’ behavior. When we can view ourselves (and help others to view us) as separate from wrong behavior, we feel better. This is similar to watching TV shows such as ‘Hoarders’ and ‘My 600 lb Life’ in my opinion. Often, the viewers that derive pleasure from these shows are those that feel good about being able to say that at least their house is not “that bad” or at least they aren’t “that large”.",
"True ELI5: \nWe like to punish people who do bad things, so they do less of the bad things. If we tell others about someone doing bad, we get more people to punish the bad person. We think this is a good thing, that's why this makes us feel good."
]
}
|
[] |
[] |
[
[],
[]
] |
||
5tcfmd
|
can churches in the united states of america offer sanctuary?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5tcfmd/eli5_can_churches_in_the_united_states_of_america/
|
{
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],
"score": [
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],
"text": [
"No, churches in the US do not have the legal authority to prevent the police from entering to make an arrest.",
"They don't have any special protections from search warrants. They are somewhat reluctant to storm a church given the optics, but when push comes to shove they'll do it anyway, ala Waco, TX."
]
}
|
[] |
[] |
[
[],
[]
] |
||
3kwu1y
|
How does the evidence support the fact that photons are particles?
|
It is claimed that the photoelectric effect demonstrates that a photon is a particle that carries a quantum of energy hv. Can't the photoelectric effect also be explained with the wave theory of light? If you can ionize an atom by subjecting it to a strong electric field, can't the electron also be ejected by resonating with the locally varying field as the photon moves through?
Thanks
|
askscience
|
https://www.reddit.com/r/askscience/comments/3kwu1y/how_does_the_evidence_support_the_fact_that/
|
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"text": [
"No, because the ionization happens depending the frequency, not the total energy of incident radiation (intensity, proportional to amplitude^2 × frequency). If the thing was purely wave-like, any wavelength of light should be able to ionize the atom, given an amplitude high enough. This does not happen, experimentally.",
"The photoelectric effect can be explained via a semi-classical approach where the atoms are described using quantum mechanics and the light is described as a classical electromagnetic wave.\n\nThere is a pretty famous paper about it by Lamb and Scully titled \"The photoelectric effect without photons.\" Note that they are most definitely not arguing that light isn't quantized, just that its not explicitly necessary to explain the photoelectric effect. The paper is a little bit controversial (as in people argue on internet forums) mostly by way of its somewhat dramatic title. ",
"A continuous wave would \"fill up the electron\" with the energy needed until the electron. IE a wave would insert x energy per second and if the electron needed 5x energy, it would take 5 energy per second.\n\nWhat we experimentally see is that this never happens. If the electron needs x energy to be released, we can shine .99x energy light waves at it for all eternity and no electrons will be emitted. As soon as it hits 1.00x, electrons come flying out. That means it's all or nothing. \n\nThe word \"particle\" is a bit misconstrued here as nobody thinks of photons as little balls of light. \"particle\" is used to differentiate this all or nothing behavior from a continuous wave behavior. Wave-like things that interact discretely is a more accurate label than \"particle.\""
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
5qcevk
|
assuming weight loss is purely about "calories in vs. calories out," how is it possible for the body to go into "starvation mode" and temporarily prevent weight loss from occurring
|
Hi all. I'm currently on my own weight loss journey, and I've noticed that even though I've been strictly counting calories, I will go through periods where my weight refuses to budge. The calories I'm consuming vs. calories burned should be low enough to cause weight loss but my body is somehow able to stave it off for days (or longer) at a time. If weight loss is really just about "calories in vs. calories out" (as I've seen even Neil DeGrasse Tyson argue), how is the body able to keep itself from shedding the weight? And, for the sake of argument, assume that I'm not making a mistake in my accounting.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5qcevk/eli5assuming_weight_loss_is_purely_about_calories/
|
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"Short answer... It doesn't.\n\nLong answer, it stores a bunch of water.\n\nSo, your body has fat cells. Those cells store fat. When they're full of fat, that's it. They're 100% full fat cells. However, as you start losing weight and using those fat stores, those cells start getting smaller. So at say 50% full of fat, it's like a half deflated balloon. So as you lose weight you get hundreds of millions of half deflated fat cells.\n\nBecause our body is super efficient, it doesn't want to get rid of the cells yet because \"we might need them again\". But also half full cells are a waste as well. So the body starts replacing the Fat with water. Once the fat cells are completely full of water for a while, the body, being as efficient as it is, decides that maintaining these cells isn't worth the effort, we were holding on just in case, but it seems we're just wasting energy to do that. That's when your body starts getting rid of the water and the cells themselves.\n\nEdit: TL:DR - Body replaces the fat in fat cells with water for a while before getting rid of the fat cells. (This is part of the reason it's important to drink a lot of water when attempting to lose weight)",
"My girlfriend told me a story earlier this week about an obese woman who was a regular at her restaurant job. She stopped coming in for one year, but then showed up at a healthy weight, mostly unrecognizable. She explained that she saw almost no weight loss for close to a year before ultimately dropping her weight \"all at once\" and says she was quite shocked. \n\nThese great answers really clarify why that might happen but it's pretty sad to think about the amount of obese people who must be giving up after a few months of seeing very dismal results.",
"Weight loss != fat loss. Water retention is a large confounding factor, especially when your diet is protein deficient.",
"What people think is starvation mode is a myth. Starvation mode exists ONLY when you are so malnourished and underweight that your organs are going to start shutting down and you will die. So as a last clutch attempt your body tries to prevent any more weight loss to prevent death. Starvation mode is not something that happens to obese, overweight, or normal weighted people.",
"Calories in vs calories out is 100% correct in that it loses fat/uses fat cells and stored energy (including muscle) as a result of the lack of energy being ingested via food sources. \n\nWith this in mind, your body will tend to reserve water when a decrease in weight is present. Now, let's get one thing clear. You don't lose fat cells, you lose the contents of those fat cells.\n\ni.e. Your fat cells remain the same throughout life, but the size, shape and storage of them increases/decreases throughout the course of your life. It would be inefficient for the body to recreate and destroy these over the course of a lifetime.\n\nFurther reading: Be careful eating a severe caloric deficits as this may impact your ability to resume a normal eating lifestyle thereafter. \n\nYou can actually reverse diet your way to losing weight by slowly increasing your food intake (without weight gain) and then having a deficit from this will result in weight loss. "
]
}
|
[] |
[] |
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[],
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|
14tyk0
|
When/How did the idea of citizenship first develop in (I believe, correct me if I'm wrong) Athens?
|
Were people gradually given de facto positions which then became obvious citizenships once the idea fully came about and was codified, or was there a bit of a process in the beginning to decide who would be a citizen and who wouldn't be?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/14tyk0/whenhow_did_the_idea_of_citizenship_first_develop/
|
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"Unfortunately, Athenian/Attic identity develops during a period of time when our sources are scant. However, most scholarship today tend to emphasize the role of the Peisistratids of forging the disparate regions of Attica into a single entity. Archaeological evidence shows that period as one of religious consolidation, as large pan-Attic monuments appear on the Acropolis, and the Panathenaic games forged a common identity.",
"The evolution of citizenship was not particularly linear. You are right that ancient Greece and Rome had \"citizens\" as a social class, but those groups were still very different than what we would today call citizens. For one they were limited in various ways, wealth, place of birth, gender, etc. In Athens, only about 20% of the total population qualified as citizens. Roman citizenship was particularly complicated especially after the rise of the empire. There were not only rules as to who could become a citizen but several different levels of citizenship for individuals living in different parts of the empire.\n\nThen there is the problem of continuity. After the fall of Rome, Roman citizenship did not retain much meaning in most of Europe. Nevertheless, some places kept at least the idea of citizenship alive. For example, in Visigothic and medieval Spain (the Christian parts anyways), cities retained a notion of citizenship within the concept of vecinidad. Individuals who qualified for vecino status were considered citizens of that city. Depending on how the city was governed, that could include voting rights for the cabildo (city council). But even in this example, there was no concept of citizenship to the kingdom. Thus, one might be a vecino of Toledo, but they were still a subject of the king of Castilla. \n\nIn most parts of medieval and early modern Europe, most of the populations were considered subjects of the king not citizens of the nation. It really isn't until after the rise of liberalism in the late 18th and early 19th c. that political thought began to conceive of national citizenship to be the core of political life. Again the evolution is not even. For example, the English Civil War of the 17th c. drastically changed the relationship between the monarchy and its subjects (particularly wealthy powerful subjects). The monarchy became more dependent on support from certain sectors of the population and lost power vis-a-vis the Parliament. On the other hand the 17th c saw the rise of French Absolutism. Even as the rest of Western Europe began to adopt ideas of citizenship in the early 19th c., Spain was a holdout. The liberal Constitution of 1812 included discussions of citizenship, but was only in force for several short periods. \n\nTL;DR Although Greece and Rome had citizens our notions come more from 18th c. political philosophy than ancient traditions. "
]
}
|
[] |
[] |
[
[],
[]
] |
|
1ozdme
|
When did doctors and psychologists begin to see sex as part of a healthy lifestyle and even necessary? Was there open debate about it?
|
Today, most doctors and psychologists will tell you that sex is healthy and even necessary for reasons wholly aside from procreation. Surely most Victorian era doctors would not have said that. Right? So how did that idea emerge?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1ozdme/when_did_doctors_and_psychologists_begin_to_see/
|
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"The one time there's a question I can tanswer, and I do not have my sources on hand, curses. With that said, there are actually a few names like Kinsey, Masters & Johnson, and a few others that come up, with Kinsey and Johnsons making the claim the claim that sex was not just for procreation. Kinsey, if I'm not mistaken, was the first to suggest treatment for transgendered individuals. Unfortunately, I do not have my text with me, but if you like I can elaborate more, later tonight? \n\n[this wiki article provides some basic info] (_URL_0_) but the text I am using for my course on human sexuality has way more information, and it's truely fascinating how sexuality is treated and how we see a change in attitude through the late 19th and 20th centuries.But again, the wiki, of course, does not have all the information\n\nedit: If promises of explanations are not acceptable, I apologize and will just elaborate later tonight ",
"In the US, the major issue regarding sex was Anthony Comstock. The view of sex as healthy did not emerge until the \"Chastity\" Laws pushed through by Comstock began to erode. Comstock began his anti-obscenity crusade in the 1860's in New York City. Appalled by what he saw in the city, he began ratting on sex trade operators to the police. This was small-time. In 1873, he convinced the US Congress to pass what became known as the Comstock Act. The law made it a federal crime to ship contraceptives through the mail or across state lines. Everyone wasn't onboard with Comstock. Margaret Sanger opposed Comstock's crusade. In 1936 U.S. Circuit Court of Appeals heard the case of United States v. One Package. The court ruled that physicians could distribute contraceptives across state lines. The Kinsey Reports were published in 1948 and 1953. Kinsey's work was soon followed by Masters & Johnson. The watershed event was probably the FDA approving \"The Pill\" in 1960. Horney Baby-Boomers were coming of age and with the pill to prevent pregnancy and penicillin to cure then known STD's it was Katy Bar the Door. \n_URL_0_",
"Well, in a lot of religions, for example Judaism and Islam, sex is seen as part of healthy lifestyle *for married couples* (which is supposed to be the \"normal state of things\" in those faiths). I'm not a medical historian, but I'd be shocked if Jewish and Islamic doctors haven't been said sex is part of a healthy lifestyle, since the beginning of those faiths. As for psychologists, perhaps the closest thing we have are the mystics, and they were really into sex (generally!! obviously there are exceptions)."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Sexology"
],
[
"http://www.pbs.org/wgbh/amex/pill/peopleevents/e_comstock.html"
],
[]
] |
|
6gmlcb
|
how does the atm count and verify cash inserted in envelopes?
|
Money is placed in an envelope and then inserted into the ATM. You also type in how much money you are depositing but presumably the machine also verifies and counts the cash that is going in.
How do machines count cash in envelopes?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6gmlcb/eli5_how_does_the_atm_count_and_verify_cash/
|
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" > How do machines count cash in envelopes?\n\nThey don't. They record the transaction and when the drop box is transferred to a bank later on the bank employees manually count and verify the amount of money was correct.",
"If it's all in an envelope, the machine doesn't verify it. It just trusts you. However, when the deposit is audited & verified later and there's only a $20 bill in there versus $2000, you're going to be in deep shit for fraud.\n\nMost cash-accepting ATMs these days don't do envelope deposits anymore. Cash is fed into the machine where it can electronically count it and deposit it accordingly. \n\nChecks are scanned and handled electronically, but the the ATM may still ask you to input or verify the amount of the check. This is another case of \"if you like to the ATM, you're on the hook for fraud\". Sure, if you accidentally enter $470 instead of $450, I doubt the bank will go after you (they'll just eventually debit the extra $20). But if you deposit a $20 check and say it's $2000, expect a knock on your door from the local police department.\n"
]
}
|
[] |
[] |
[
[],
[]
] |
|
1ayx9l
|
How devastating would a kinetic weapon (projectile dropped from orbit) actually be?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1ayx9l/how_devastating_would_a_kinetic_weapon_projectile/
|
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"By increasing distance from earth and mass, you could scale them up to the size of the impact that created the moon. The question is why you would do that. Much easier to pack explosives into a vehicle that doesn't have to travel that far.",
"Popular science has a short article: [Rods from God](_URL_0_).",
"A telephone pole is about 12 meters tall with a radius of about 23 cm. Conveniently this is a volume of almost exactly 2 cubic meters. Tungsten has a density of 19250 kg / cubic meter. So the mass of a tungsten telephone pole is about 38500 kg.\n\nTerminal velocity of a dropped bullet is about 90 m/s. Using that velocity with the above mass gives a kinetic energy of about 156 MJ.\n\nThe Hiroshima atomic bomb had a detonation energy of around 60 TJ, which is about 385x more energy."
]
}
|
[] |
[] |
[
[],
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"http://www.popsci.com/scitech/article/2004-06/rods-god"
],
[]
] |
||
3ho6t7
|
META: Can we talk about the clear increase in "throughout history" or trivia-seeking questions?
|
_URL_0_
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3ho6t7/meta_can_we_talk_about_the_clear_increase_in/
|
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"You're becoming more popular. The more casual people that join the group, the more superficial questions it receives. ",
"nsdwight has the gist of it. As the sub grows, we attract a larger audience, an audience that, unfortunately, contains more people who don't know the rules and don't bother to read them. We do our best to filter vague and low-effort questions, but can't catch all of them. If you see them, report them! Everyone can contribute.\n\nUnless you're talking about submissions that are not being removed- if that's the case, care to provide examples?",
"I just hit report when I see these types of questions on this subreddit. It usually gets taken down within 15 minutes after that. If it's been up for a while, I send a moderation message to make sure the report gets seen (partially because \"ignore reports\" is a thing and partially because it's pretty difficult to accidentally miss an orange-red message indicator).\n\nAlso, yes, it's likely just growing pains. People often don't read the rules thoroughly before posting. That's why moderators are here."
]
}
|
[] |
[
"https://www.reddit.com/r/AskHistorians/wiki/rules"
] |
[
[],
[],
[]
] |
|
8jk8ta
|
What is the minimum amount of gravity of a planet needed to sustain a breathing atmosphere?
|
You may express the value in terms of Earth's gravity, such as 0.5g, 0.8g etc. So, for example, would Mars ever be able to sustain breathing atmosphere with its paltry 0.38 Earth's gravity even if a plausible terraforming project that introduces oxygen-rich atmosphere to the planet is undertaken?
|
askscience
|
https://www.reddit.com/r/askscience/comments/8jk8ta/what_is_the_minimum_amount_of_gravity_of_a_planet/
|
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"Don’t know the math for this, but Saturn’s moon, Titan has a very thick atmosphere but only has about 2% the mass of Earth. Other factors play into a planet having an atmosphere, though. A good magnetic field prevents solar wind and deadly cosmic rays from stripping one away.",
"This is a complex question. Mars may have had an atmosphere with conditions similar to that of earth, such that liquid water could exist out in the open. However, Mars' atmosphere slowly eroded over time, due to solar wind.\n\nSo the question is, could a planet not only sustain an atmosphere of a given composition, but could it hold onto that atmosphere long term? \n\nThis will depend not just on the gravity of the planet, but also on what you presume it's atmosphere's composition is, and on the average temperature given.",
"As a general rule: A gas escapes over geological timescales if the escape velocity is less than ~8 times the typical speed of this gas in the atmosphere ([Jeans escape](_URL_0_)). If the escape velocity is higher, it can still lose its atmosphere via other processes, e.g. induced by sunlight.\n\nThe typical speed is proportional to the absolute temperature divided by the particle mass. The escape velocity is proportional to the square root of (the planet's mass divided by the radius). Planets with the same surface gravitational attraction can have different escape velocities.\n\nSome caveats: The relevant temperature is not the surface temperature, but the temperature in the upper atmosphere. For Earth this is 1400 K, for example. The escape is usually dominated by the lightest gas - for oxygen this is not O2, but H2O or even individual oxygen atoms.\n\nMars can hold an atmosphere for millions of years - very long on human timescales, but very short compared to the age of it.\n\nTitan can hold it even longer as it is colder."
]
}
|
[] |
[] |
[
[],
[],
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"https://en.wikipedia.org/wiki/Atmospheric_escape#Thermal_escape_mechanisms"
]
] |
|
1gj1m7
|
Can you feed a bird so that it gets too fat to fly? Or would it die from health complications before it ever reached that point?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1gj1m7/can_you_feed_a_bird_so_that_it_gets_too_fat_to/
|
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"There you go. This [kookaburra](_URL_0_) ate way too much bbq and could no longer fly.",
"Not birds, but there was an interesting study where they increased the mass of bats by injecting saline into their peritoneal cavities and studied their flight characteristics under varied loading.\n\n1. J Iriarte-Diaz, DK Riskin, KS Breuer, SM Swartz (2012) \"Kinematic Plasticity during Flight in Fruit Bats: Individual Variability in Response to Loading\" PloS One 7 (5), e36665\n2. Leigh C. MacAyeal, Daniel K. Riskin, Sharon M. Swartz and Kenneth S. Breuer (2011) \"Climbing flight performance and load carrying in lesser dog-faced fruit bats (Cynopterus brachyotis).\"Journal of Experimental Biology214 786-794",
"I remember hearing at a lecture about birds given by a guy who runs a conservation that some types of vultures will eat until they can't fly because they don't find meals that often, and will just walk on the ground until a predator appears, in which case they will vomit in its face to distract/blind it, thus lowering their weight and letting them fly again.",
"It's common to see wedge tailed eagles in the Australian outback who have gorged on dead kangaroo or other roadkill to the point where they can't fly away anymore. They usually die from not being able to get out of the way of other oncoming vehicles.",
"The answer is yes. In both domesticated birds and captive wild birds they can gain weight to the point of being unable to fly. Flying is exercise, and weight is a burden, and all the pneumatized bone in the world won't undue an extra body weights' worth of fat. \nSource: I'm an avian vet. ",
"City pigeons rely too much on food from tourists and such that they get so fat they can't fly. Seriously, go to your nearest city attraction and look at all the fat flightless pigeons.",
"As a pigeoner and a person with friends that are falconers I can tell you the answer is yes. A falvons weight must be maintained properly for them yo hunt and return to the falconer. I have personally had pigeons that could barely get off the ground because the food i was feeding was to high in protien and fat. Overall weight is really important when it comes to birds. If they are too fat they will not fly well. Even fatter and and they cant get off the ground.",
"Not really an answer to your question, but I believe many species of vultures will gorge themselves to a point where they cannot fly since they've gotta make the most of their meals... If something spooks them, they'll regurgitate their meal so they're light enough to fly again.\n\n\nedit: someone already posted this fact..."
]
}
|
[] |
[] |
[
[
"http://www.news.com.au/weird-true-freaky/sausage-addicted-kookaburra-too-fat-to-fly/story-e6frflri-1225872729208"
],
[],
[],
[],
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[],
[],
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||
1hq93f
|
Can an ant find its way home?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1hq93f/can_an_ant_find_its_way_home/
|
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"Depends... the Argentine ants have a mega-colony in CA that stretches over 560miles.\n\nThe long and short of it is that ants are blind without chemical scent trails. So unless his home colony has ants that have made it a mile away into your yard, the ant will not find its way back.\n\nIt would in all likelihood get attacked by your yards colony. There are rare exceptions of colonies that take \"prisoners\", but probably not in your yard. "
]
}
|
[] |
[] |
[
[]
] |
||
10t6ge
|
Istanbul to Ankara: What factors were involved in the switch?
|
I would be very interested in some information that could help me understand what factors ultimately led to the Turkish government in moving their capital city status to Ankara. I think the Middle East is sometimes overlooked in an ever increasingly Eurocentric/Sinocentric world that I see, so I think it would be helpful for me to learn some of the fundamentals before digging deeper. Thank you for your time.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/10t6ge/istanbul_to_ankara_what_factors_were_involved_in/
|
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"Ankara became the capital because it was used by Atatürk as his headquarters while Constantinople/Istanbul was occupied by the Allies. The Grand National Assembly was established there. That's the main reason.",
"In addition Istanbul (or Konstantiniyye) had for long been the symbol of the multi-cultural ottoman empire (and ofc. the greek, byzantine empire), containing significant amounts of non-turkish elements (specifically Greek) which Atatürk despised. \n\nWhen Atatürk wanted to create his new turkish national state Istanbul simply had too much history behind itself to be used as the symbol of a revolutionary nationalistic and modern moment. Ankara were thus preferred.\n\nIn addition the aforementioned \"occupation\" of Istanbul by the allied powers greatly influenced the decision as you cant really lead the struggle against the greeks from occupied territory. \n\n",
"It seems very similar to the switch from Petrograd to Moscow ",
"I've also heard it said that Ankara was preferable because it was in land; making it less susceptible to attack. ",
"I suggest reading Reset: Iran, Turkey and America's Future, by Stephen Kinzer. It goes into great detail surrounding Istanbul to Ankara and how Turkey became the first secular muslim state.\n\nIf you're interested in the middle east and how it is over looked throughout much of history, I suggest reading Destiny Disrupted: A History of the World through Islamic Eyes by Tanim Ansary. It is one of my favorite books.\n\nThey are both really easy reads and seriously have changed my outlook on the middle east, how the west interprets middle eastern history etc. I highly suggest them!",
"It’s interesting, reading these responses, to see that Istanbul/Constantinople lost its status as a capital for many of the same reasons Constantine made it a capital to begin with: the “new” capital was in a more central location, the “old” capital was geographically isolated and vulnerable, and the new regime wanted to make a cultural break with the past."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[]
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|
805noh
|
Questions regarding nicknames
|
Why were the north Vietnamese called Charlie in the Vietnam war
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/805noh/questions_regarding_nicknames/
|
{
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"text": [
"The Viet Cong were referred to using the military phonetic alphabet (V-C = Victor Charlie) shortened to Charlie."
]
}
|
[] |
[] |
[
[]
] |
|
3bxlcw
|
how is it legal to have tinted license plate covers?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3bxlcw/eli5_how_is_it_legal_to_have_tinted_license_plate/
|
{
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"The ones I've seen leave the license plates readable, the idea is if a speed trap camera takes a picture it'll make the plate unreadable in the photo. Fortunately they don't actually work, so no one really cares.\n\nIf your plate is obscured to the point where you can't read it with the naked eye, it is extremely illegal.",
"The law is not protecting you. They broke the law by hiding their plate. The law only effects law breakers. If they are caught breaking the law, they will be punished. If someone chooses not to follow the law, well we are all screwed."
]
}
|
[] |
[] |
[
[],
[]
] |
||
2nn05r
|
vampires might not be real, but how exactly does the internal anatomy work of creatures that live strictly off of blood?
|
I have researched mosquitoes, fleas, bats, and leeches. But I still do not properly understand how blood can be the only life sustaining nutrition they need.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2nn05r/eli5_vampires_might_not_be_real_but_how_exactly/
|
{
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"text": [
"Their anatomy isn't that different from other similar animals. They drink blood which goes into their stomach and is digested to get nutrition. There is a lot of energy to be gained from eating blood just like eating other parts of an animal."
]
}
|
[] |
[] |
[
[]
] |
|
1sntkh
|
why are tv cooking shows allowed to kill live animals but other tv/movies can't harm animals?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1sntkh/eli5_why_are_tv_cooking_shows_allowed_to_kill/
|
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"Any TV/movie can kill animals they just choose not to. In Pink Flamingo they kill a chicken for example. ",
"Besides lobsters I don't think I've seen any live animals being killed on cooking shows in the US. ",
"I'm not sure if they're not allowed, or if networks are just unwilling to suffer the backlash that they'd receive from animal right's activists. IIRC survivor had a huge flap a couple years ago because they killed a hog.\n\nIn terms of justification, cooking shows that feature meat necessarily require the killing of animals, and showing that really can't be criticized. Animal rights advocates would probably like more shown because it would force people to see where their meat comes from, step by step. TV shows that are primarily entertainment would have a harder time justifying the killing of animals for mere entertainment's sake. If Game of Thrones went around killing horses on purpose just for realism, they'd be crucified in the court of public opinion. ",
"Nothing under US law prohibits the airing of content that shows violence against or the killing of live animals. \n\nContent providers largely self impose not airing animal abuse as it would upset program advertisers by associating them with less than reputable content, audiences have a cultural predisposition to be against unnecessarily harming animals, and building an image of someone who provides that kind of content reflects poorly on a businesses brand. "
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
5k35nw
|
What was the mindset for veterans who lived through both WW1 and WW2
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/5k35nw/what_was_the_mindset_for_veterans_who_lived/
|
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],
"text": [
"What was the \"mindset\" for them? And are you looking for generalities, because there were a LOT of veterans with a lot of different thoughts about a lot of different things. What does your question actually mean? I don't think you can possibly get a substantive answer to this question, as vaguely worded as it is.\n\nThis subreddit needs an FAQ on how to write a question about history that can actually be answered in the way the subreddit itself demands answers."
]
}
|
[] |
[] |
[
[]
] |
||
3ccn25
|
what is the theoretical limit to wireless communication transmission speed? what is the limiting factor?
|
This question ocurred to me when I read that the communication delay from Pluto to Earth is 5 hours (one-way). Could this delay be decreased by installing wireless or laser transmitters every half-billion miles?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3ccn25/eli5_what_is_the_theoretical_limit_to_wireless/
|
{
"a_id": [
"csuacq6"
],
"score": [
3
],
"text": [
"There's two factors:\n\nThere's the speed of light, which limits the *latency* — the delay between sending and receiving.\n\nThe second is *bandwidth*, which is how much data can be sent in a certain amount of time with a certain amount of power.\n\nThe Pluto probe currently has a bandwidth of about *1 kilobyte per second*. This upper limit exists because the *modulation* of the signal — shifting it up and down in frequency — has to be slower, the pulses have to be longer, to prevent them from being drowned out by background noise.\n\nIf the probe could transmit with more energy, the pulses could be more easily distinguished from background noise, and so could be shorter, and the bandwidth increased. \n\nThere's nothing that can be done about the *latency*. That's a hard limit on the physics of the universe.\n\nIf there were amplifiers / repeaters every so often along a path between the probe and Earth, the *bandwidth* **could** be increased, because the power of the transmission would be stronger, the closer it physically is to the receiver. \n\nThere are, of course, significant logistics challenges behind deploying, powering, and managing those hypothetical amplifiers and repeaters."
]
}
|
[] |
[] |
[
[]
] |
|
45lpvg
|
is there any solid reason why we view/record videos and pictures in a rectangular way. and why not just a square?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/45lpvg/eli5is_there_any_solid_reason_why_we_viewrecord/
|
{
"a_id": [
"czynj3e",
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"score": [
108,
63,
12,
6,
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],
"text": [
"This has been asked in various ways before though I'm pressed to think up good search terms. \n\nA simple answer is that our field of vision of wider than tall so it makes sense for video to be the same.",
"If you close one eye, you'll see a round field of view. However, humans have two eyes separated by some distance. With both eyes open, we get a elliptical field of view that is wider than it is tall.\n\nThis is turned into a rectangular field of view because it is easier to make rectangular camera film and camera sensors than elliptical ones.",
"A landscape format rectangle mimics how our eyes normally see. Furthermore, our eyes normally scan images horizontally. Most writing is done side-to-side, only a few languages use top-to-bottom writing (and even those languages sometime use side-to-side formatting).\n\nAs to the relative dimensions of the rectangle, called the aspect ratio, various formats have been used over the years, and continue to be used. The earliest movies were just shot in a simple square format (ie aspect ratio of 1:1). But as filmmaking became more sophisticated, people started experimenting with other aspect ratios.\n\nIn general, people just prefer watching movies in non-square aspect ratios, whether it's a common 4:3 ratio or the 2.35:1 ultra-wide format of Cinemascope, which was used for a lot of sweeping epic films in the 50s and 60s.\n\nThere has never (to my knowledge) been a popular format for films that is taller than it is wide, which is why when people record videos with their phones held vertically, it just looks *wrong* to us.\n\n\n",
"The history of aspect ratios is quite complicated. The academy ratio was established to allow sound to be stored in 2 edges of approximately square frames, so that the video portion had an aspect ratio of about 1.37, which TV mimicked with 1.33. Cinemas decided to be as different from TV thereafter as possible, thinking ultra widescreen would give people a motivation to continue attending film screenings. This is why 2.35 became so common. The golden ratio (about 1.62) has never been used as an aspect ratio staple.\n\nHDTV was designed to be 1.78 so that it would compromise between ultra-widescreen films and old TV shows, and each would take up about the same majority of the screen if uncropped. (The trick was to use a geometric mean of two common aspect ratios, as too much cropping looks bad.) Nowadays film-makers have become happier about working with roughly this aspect ratio. The hope now is that Blu-ray releases will be similar enough to a full cinema experience to sell well.\n\nAs history has run its course, a number of aspect ratio stereotypes have become established. For example, 1.78 is typical of documentaries, while 1.33 is typical of very old films and pre-2000s television. Some TV and film productions have been made in aspect ratios chosen to ape such stereotypes for works that want to ape a certain genre. For example, some comedy films that seek a fake documentary feel go with 1.78, while *The Artist* made sure to use the same aspect ratio as silent films.",
"Because it's efficient. Most of what we are interested in seeing is happening on the surface of the earth, which is way wider than it is high. Those vertical videos recorded on smartphones are so annoying because they show a lot of uninteresting sky at the top and ground at the bottom, and what is interesting is crammed into a little space in the middle, and you may be missing some maybe-relevant stuff off to the sides.",
"Glove and Boots do a good job of explaining thoughts on a very concerning condition that helps answer you question.\n\nVertical Video Syndrome \n\n_URL_0_\n"
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[
"http://youtu.be/Bt9zSfinwFA"
]
] |
||
46q0gi
|
Are all the particles in the universe quantum entangled or does that only happen under specific conditions?
|
askscience
|
https://www.reddit.com/r/askscience/comments/46q0gi/are_all_the_particles_in_the_universe_quantum/
|
{
"a_id": [
"d07q0bx"
],
"score": [
3
],
"text": [
"I would argue yes as entanglement as well as superposition are intrinsic aspects of a quantum world, but saying that 'everything is entangled' is not a particularly useful or helpful notion. The reason for this is that entanglement happens too much and too easily killing all the delicate quantum effects we so carefully try to cultivate in the laboratory. This process is called decoherence and is a major reason why the weird quantum world generates \"classical\" physics as we move to larger systems. Here's an excellent enthusiast level look at it: \n\n* Zurek. Decoherence and the transition from quantum to classical -- REVISITED. PHYSICS TODAY, 44:36-44 (1991/2003) _URL_0_\n\nWhat people call EPR entanglement is more correctly described as isolated entanglement. Systems which are allowed to coalesce with each other, but not with the outside world. This only happens under specific conditions."
]
}
|
[] |
[] |
[
[
"http://arxiv.org/abs/quant-ph/0306072"
]
] |
||
blr6rs
|
how does the weather change so drastically for just a few days and then go back?
|
The last couple of days it has been beautiful and warm. Today and tomorrow it is supposed to be cold and snowing, and then it is forecasted to go back to sunny and warm. Why does it just sometimes get cold and snow in the middle of an otherwise lovely week?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/blr6rs/eli5_how_does_the_weather_change_so_drastically/
|
{
"a_id": [
"emqrsfr"
],
"score": [
2
],
"text": [
"If you have ever listened to the weather man you've probably heard the term \"Cold front\" or \"Warm front\" as they tell you the weather. These fronts are masses of air with various attributes, they could be cold & moist, warm & dry, warm & moist, etc. The leading edges of these fronts are pretty strong and they can push away or go under the current mass of air in an area, when this happens the weather changes.\n\nSometimes these changes are just drops or increases in temperature, sometimes these changes result in lots of steady rain, and sometimes they result in violent thunderstorms. **But the ELI5 is that there are masses of air types floating around and they push and interact with each other and help create our weather.**\n\nSo right now a cold front has entered your area and probably has gone under the warm air you've been having and once that cold air has left your warm air will will return (although it really never left, in some cases it was just above the cold front!)"
]
}
|
[] |
[] |
[
[]
] |
|
3v3cbl
|
why is being transgender not considered sexist?
|
I fully support transgenders, but I cant help but get the feeling that when a transgender person says they feel like they were born in the wrong body because they like to do this or that, a little bit sexist.
To help you get a better understanding, lets say, a male thinks he is born in the wrong body and feels like a girl because he likes playing with dolls and wearing makeup.. well to me that is kinda sexist because who is to say a boy can't wear makeup or play with dolls. Toys, makeup, clothes, certain activities (cooking, shopping), and colors do not have a gender. If you are a straight cis male and like the color pink or love makeup, thats awesome, these things should not be limited to one gender. Liking these stuff should not mean that you are a transgender.
However i do understand how that a person might feel like they were born with the wrong genitals and this is what causes them to be transgendered, because thats not where the sexism comes in to play. The sexism comes in to play in my opinion when a person feels like they are the opposite sex because they want to be able to do what that gender does. I really want help understand this. Thanks.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3v3cbl/eli5_why_is_being_transgender_not_considered/
|
{
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"text": [
"imagine you were in the other gender's body, but had all the exact same thoughts and interests as you do now. that is a bit different than just a boy who likes dolls.",
"It isn't about the things you like to do, it's about who you feel you are. These things are quite different. Like you said, if a boy wants to play with barbies or a girl wants a toy gun, whatever! It doesn't have anything to do with being transgender. I think the confusion for you might be coming from the fact that if children exhibit these traits and then grow up to be transgender it's not because those things are inherently \"girl things\" or \"boy things\" but because culture often dictates that they are. So if a little boy feels like a girl (but doesn't know how to express it) he will do things that in his mind feel right, and those things will often be things that his culture has deemed \"girl things\".",
"Liking feminine or masculine things doesn't make someone a man or a woman, but in transgender people it just seems to be symptom of the condition. \n\nOne of the surprising things about being transgender is that transgender children tend to play with toys that are opposite of their natal sex, they tend to predominately play with kids opposite of their natal sex (kids usually play with other kids of their own gender), and prefer clothing opposite of their natal sex. \n\nPsychologists even use these activities to diagnose the children:\n\n > To be diagnosed with gender dysphoria, a person has to have symptoms that last for at least six months.\n\n > In children, these symptoms may include:\n\n > Consistently saying they are really a girl even though they have the physical traits of a boy or really a boy if they have the physical traits of a girl\n\n > Strongly preferring friends of the sex with which they identify\n\n > Rejecting the clothes, toys, and games typical for boys or girls\n \n > Refusing to urinate in the way -- standing or sitting -- that other boys or girls typically do\n \n > Saying they want to get rid of their genitals and have the genitals of their true sex\n \n > Believing that even though they have the physical traits of a girl they will grow up to be a man; or believing if they have the physical traits of a boy they will still be a woman when they grow up\n \n > Having extreme distress about the body changes that happen during puberty\n\n_URL_0_\n\nNote that a child must have body dysphoria symptoms and insist they are or want to be the opposite sex to get a diagnosis, so gender non-conforming kids wouldn't make it.\n\nThat's just the way science understands the condition. Just as another piece of evidence, have you ever seen a trans woman who chooses to dress in masculine clothes everyday? Or a trans man who wants to dress in feminine clothes everyday? I haven't. This behavior really needs explaining. My interpretation is gender identity causes the individual to generally (not 100% of the time) imitate other people of their gender identity.\n\nHowever I would agree that someone saying they knew they were a woman because they like feminine things is a tad sexist. There are a significant amount of people who are gender non-conforming. A better statement would be that liking things of the opposite gender is a sign that some is transgender (though it's not a perfect sign).",
"I feel like you're not going to get a rational explanation on this topic. Let me just point out that there are plenty of men who act very feminine, and vice versa, who feel absolutely no need to get surgery, so for those who do, the motivation has to go beyond just the desire to participate in activities considered appropriate for the opposite gender, since as you pointed out, there's nothing wrong with a person feeling comfortable with themselves while behaving in a way customarily associated with the opposite gender. "
]
}
|
[] |
[] |
[
[],
[],
[
"http://www.webmd.com/mental-health/gender-dysphoria?page=2"
],
[]
] |
|
sk543
|
If forced to spin, whether for a game or as a contest, what is the most effective way to avoid sever dizziness?
|
askscience
|
http://www.reddit.com/r/askscience/comments/sk543/if_forced_to_spin_whether_for_a_game_or_as_a/
|
{
"a_id": [
"c4enhwd"
],
"score": [
2
],
"text": [
"Do what ballerinas do. Keep your head in one position and turn it fast and stop, fast and stop, fast and stop. This is precisely why they do this - to not get dizzy."
]
}
|
[] |
[] |
[
[]
] |
||
zxa7f
|
Wondering about the origins of current Japanese cultural norms
|
Today, I hear consistently about how strict Japanese cultural norms are and that very little emotion is shown, even in a typical familial relationship. To my naive, untrained self, this seems somewhat similar to Victorian culture. I'm curious as to the origins of this culture, and how long it has been the case. Unless I'm completely misinformed, in which case, please let me know!
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/zxa7f/wondering_about_the_origins_of_current_japanese/
|
{
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"c68iu3m",
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"score": [
6,
2,
3,
2
],
"text": [
"Japanese people show emotion... they're just more subdued about it, and you need to look for non-verbal clues a bit more than you're probably used to.\n\nIt was considered a loss of face to show strong emotions in public, if you're asking about the origin of this.",
"This is conjecture, but I wouldn't be surprised if the severe homogeneity of their culture and population makes it a great deal easier to pick up on nuanced social cues and empathise with one another without overt displays of emotion like a more mixed population tends to produce. Probably talking bollocks, but it gave me pause for thought.",
"As ShakaUVM suggested, there's simply a lot of non-verbal or non-explicit expression. Some of it will also play out more explicitly in word choice, as word choice is a bit less ambiguous in Japanese than in English with explicit degrees of politeness by conjugation and word choice. That said, there's a lot of value placed on being essentially 'psychic' and picking up contextual clues well enough to not be told something explicitly.\n\nMy hypothesis as to the origin of this is that a resource poor nation aspiring to Imperial China seeks minimalism/nuance as day to day expression rather than grandiosity (comparatively) and it begins to infect other parts of culture and language.",
"Misinformed - totally. There's a very healthy and life-affirming display of emotion in Japan, in and out of families. Lived there for 20 years, so have some experience.\n\nEnglish speaking individuals tend to communicate emotions verbally. They get a bit buggered when they come across people who don't just use verbal, and even more buggered when they don't speak the other language reasonably fluently too.\n\nEnglish speakers convey a vast range of subtle emotions with their language - imagine speaking another language to that level of fluency. That needs to be done before emotional communication can be asessed - and that's without the nonverbals."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
|
35gcv2
|
Looking to learn more about Canadian History
|
This is my first question on this forum, so I apologize if I have worded this incorrectly or in the wrong forum. As a Canadian, I did of course learn about my own history throughout public and high school, however all we really had were textbooks that didn't go into the full details of history (essentially a summary), so that in the next grade you could learn more about it.
Is there any specific books, documentaries, or websites where I can find more information? Ranging from pre-colonial times to Modern times if possible, of any topic (warfare, architecture, daily life, ect.)
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/35gcv2/looking_to_learn_more_about_canadian_history/
|
{
"a_id": [
"cr45lor"
],
"score": [
5
],
"text": [
"From my perspective — and it's biased toward the Yukon/Alaska — I'd recommend working your way through Pierre Berton's bibliography. While he wrote some duds here and there, most of his 50 titles are pretty good.\n\nI'd recommend *The Klondike Fever*, *The Promised Land: Settling the West* and *Marching As To War* as three to get you started. Those three condense a lot of his bibliography. Once you've gotten through those, grab his two volumes on the War of 1812 (one covers 1812-1813, the other 1814-1815) his two volumes on the Canadian Pacific Railway, *The Arctic Grail*, *Vimy*, *Niagra* and *The Great Depression.*"
]
}
|
[] |
[] |
[
[]
] |
|
1hrt0o
|
why as seen on tv products are sold in "3 payments of $19.95" or something like that.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1hrt0o/eli5_why_as_seen_on_tv_products_are_sold_in_3/
|
{
"a_id": [
"cax8qx0",
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"score": [
15,
2
],
"text": [
"Primarily for two reasons: \n\n1) Splitting up the cost of a product over multiple payments gives the potential buyer the impression that the product is actually cheaper than it is. Ex. One payment of $60 vs three payments of $19.99. The fact that the sellers do not round up is also by intention. Even though we see $19.99 or $19.95 we don't equate that with $20, our immediate association puts it with $19 which seems cheaper to us. \n\n2) There is some flexibility with these payments as by being able to pay in installments reduces a small portion of the financial burden on the buyer - making him/her more likely to buy it. It's like saying \"Well, okay, I can pay $19 bucks this month and get the product, and worry about the two other payments later!\" Out of sight - out of mind. Hope this helps!",
"Your brain doesn't process things intelligently that's why.\n\nYou see 19 and your brain thinks it's cheaper. \"Only *three* payments of 19? What a steal!\"\n\nInstead of just looking at it and going \"Yeah, Sixty bucks got it.\"\n\nEdit: Just to clarify, I wasn't saying you're dumb, I was saying we're all dumb."
]
}
|
[] |
[] |
[
[],
[]
] |
||
calzmf
|
Were wolves domesticated only once, with all dogs descended from that single progenitor population, or did the process of domesticating wolves occur independently in different societies?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/calzmf/were_wolves_domesticated_only_once_with_all_dogs/
|
{
"a_id": [
"et9t25y"
],
"score": [
12
],
"text": [
"While we have a fair bit of overlap, given that this predates written history, you may want to consider X-posting this to /r/AskAnthropology as well as this falls within their purview. And for that matter, I would note that /r/AskScience would also be an appropriate venue given the biological science aspects of the question."
]
}
|
[] |
[] |
[
[]
] |
||
47q8uf
|
Are fields real or just a mathematical tool?
|
For example, does a charged particle physically interact with some electric field or is the electric field just a convenient way of describing that particle?
|
askscience
|
https://www.reddit.com/r/askscience/comments/47q8uf/are_fields_real_or_just_a_mathematical_tool/
|
{
"a_id": [
"d0fztuo",
"d0gezxe"
],
"score": [
11,
5
],
"text": [
"The strongest statement physics can ever make is \"this model makes accurate predictions.\" It cannot tell you whether the model is what's \"really\" going on or not, because there is no other way to test the model.\n\nWhether something is \"real\" or not is a matter of philosophy. You could argue that any model which makes perfect physical predictions is reality because all correct descriptions of reality are equivalent, sort of like they're just different languages expressing the same concept. I dunno, it certainly isn't science at that point.",
"This is a really interesting question and draws not only on physics but also philosophy and ontology (what really exists). \n\nI wrote out several answers to this question but none of them felt adequate to me (continuously backspacing and re-typing). \n\nFields are an excellent model for a large number of phenomena, and provide excellent predictive power. However, models don't equate to reality. There is in fact no test for what is \"real\", because what appears to be real on our length scales is modelled to be completely different on a different length scale (for example the fact that atoms are 99% space, but we seed objects as \"solid\"). \n\nAnyway, philosophy really deals with the ontology of scientific models and statements. It's an interesting subject. But from a physics standpoint, the ontology of fields isn't really \"provable\". \n\nBut... to try and answer your question, we use fields in (e.g. Electromagnetism) to generalise what we predict to be virtual particle interactions, and this video describes this phenomena well: \n\n_URL_0_\n\nHope this helps"
]
}
|
[] |
[] |
[
[],
[
"https://youtu.be/WUnDsNL_5nk?t=38s"
]
] |
|
4bp8ad
|
why is it more common for employers to provide health insurance plans as opposed to individuals getting their own insurance? why doesn't this group approach differ from other types of insurance, like home, life and auto, where customers often get insurance directly with an insurance company?
|
I'm speaking from the standpoint of the United States. I realize this varies greatly in other parts of the world.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4bp8ad/eli5_why_is_it_more_common_for_employers_to/
|
{
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"d1b7yjz",
"d1b81um",
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"d1bvpjz"
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2,
2,
2,
2
],
"text": [
"This is an accidental remnant of wage controls during the world war. Certain industries could only offer so much salary, ao they started offering healthcare as an artificial raise. Then that became expected. Then it started to become law. Businesses could negotiate good rates, and paying 5k for someone's healthcare saved you the taxes that having to pay that in salary would cost. Eventually you were told that the goal of adulthood was to find a job that offered a good salary and healthcare.\n\nIt really isnt a system anyone would set up intentionally, but it accidently started and has slowly become too \"normal\" for most people to consider changing it.",
"It began during World War II, when the government restricted employers from raising employees' wages, so they had to attract good people by offering benefits including health insurance. At some point, we decided to make it tax-deductible for employers, and then every employer jumped on the bandwagon.",
"Historically speaking, health insurance was a fringe benefit offered to attract workers at a time when wages were frozen (due to the WWII war effort). Offering insurance was a way to circumvent the restriction, and greatly benefited companies to attract labor due to the shortage of workers. \n\nOf course, it does predate WWII. Health insurance was formed for more labor intensive work (i.e, mining) to safe guard the workers from the hazard of the job. After WWII, the trend with businesses stuck and health insurance companies grew into businesses themselves that benefited off it. ",
"There's a concept in insurance called anti-selection. People who know their house is in a place subject to fires or hurricanes will tend to seek insurance. People who know their health isn't perfect will tend to seek life insurance. All of this leads to a tendency for insurers to see more claims per policy than would be the case if they were insuring a random sample. Group insurance helps with this to some extent. When an insurer sells a policy to a big employer it gets closer to a random sample. Some of the employees will turn out to be sick, some will be healthy but it is less likely that the average group member will be sicker than what would be expected from a random sample. \n\nThis isn't perfect of course. People with health issues will try to find jobs with an employer who offers health insurance. People who develop health issues after becoming employed will tend to stay in their jobs to keep their insurance. \n\nThis is one reason why national health care can be more efficient than the system we have in the USA. Everyone pays into the system via taxes. Everyone sick and healthy is covered."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
|
ucekg
|
How do fields form, especially those right next to densely wooded areas?
|
Why are there naturally occurring large expanses of mostly flat, grassy land? Why do trees or other larger plants generally not grow on this land, and if they do, why are they so isolated from other ones?
|
askscience
|
http://www.reddit.com/r/askscience/comments/ucekg/how_do_fields_form_especially_those_right_next_to/
|
{
"a_id": [
"c4u67cd"
],
"score": [
2
],
"text": [
"Can you give an example of this?\n"
]
}
|
[] |
[] |
[
[]
] |
|
6uy3oz
|
why does it sound odd shortening "you are" to "you're" in the sentence "i'm ready when you are"?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6uy3oz/eli5_why_does_it_sound_odd_shortening_you_are_to/
|
{
"a_id": [
"dlw8u1c"
],
"score": [
8
],
"text": [
"Because in this form the word *you* is emphasized, spoken more loudly. So also emphasizing the *are* leaves the listener wondering: *are* what?"
]
}
|
[] |
[] |
[
[]
] |
||
lkors
|
Do arteries unclog eventually? Or is plaque build up permanent?
|
Is there anything in the body that breaks down the plaque?
|
askscience
|
http://www.reddit.com/r/askscience/comments/lkors/do_arteries_unclog_eventually_or_is_plaque_build/
|
{
"a_id": [
"c2tgkpy",
"c2tgp16",
"c2thyz9",
"c2ti7vi",
"c2tgkpy",
"c2tgp16",
"c2thyz9",
"c2ti7vi"
],
"score": [
15,
13,
2,
3,
15,
13,
2,
3
],
"text": [
"HDL participates in a process called [reverse cholesterol transport](_URL_0_) that can remove ~~plaque~~ cholesterol from peripheral tissue. As qxrt points out, this might not remove the plaque itself.",
"HDL carries lipids back to the liver and can reduce the rate of the plaque-forming process through reduction of inflammation and sequestering of cholesterol, but once the actual plaque forms, it becomes calcified, and it's relatively permanent. I only say relatively since it's likely that there are some processes going on that reduce the plaque (since most biological systems are in a constant state of flux, with opposing forces balancing out to create homeostasis).\n\nI'm personally not familiar with whether there's research to take advantage of any existing mechanisms of plaque breakdown, but current treatments involve either installing a bypass artery or busting open the artery, plaque and all, with a stent. There's no current treatment that removes the plaque itself. ",
"It really depends on how much plaque you have. Arteries can actually be partially clogged up to around 70% and you would still be fine (assuming you don't exert yourself too much) as certain arteries will enlarge or shrink in diameter to move blood throughout body properly. At that point, you may or may not want the plaque (usually calcified cholesterol and fat) to breakdown. If large pieces of plaque don't get dissolved, but stay in large chunks you might end up getting a stroke or a heart attack depending on where the plaque breakdown occurs. So in the case of stroke or a heart attack, blood is something in the human body that can breakdown plaque. \n\nNon-calcified fat may be reversible. Also it's important to realize plaques do not form everywhere in the arterial system. They generally occur in spaces with retrograde or stagnant blood flow. One reason why aerobic exercise is important is that it mechanically induces the epithelial cells in your blood vessels to produce more nitric oxide which prevents or inhibits fat from attaching to the arterial surface.",
"There are also ways to mechanically \"unclog\" arteries although their long term effectiveness rates are moderately low and patients often require repeat interventions to ensure that their arteries remain patent.\n\nPictures may be NSFL.\n\nOccluded arteries in the periphery (carotid, femoral, iliac, popliteal, etc) are treated through a variety of means. There are large \"open\" procedures to treat [occluded femoral arteries that often involve using vein or graft to establish flow](_URL_2_) or - [surgical dissection of the carotid artery](_URL_0_). \n\nOther-times, practitioners can approach an occluded vessel [percutaneously through an access catheter](_URL_1_) (of varying diameter, from 4french through 28french for some aortic stent grafts)",
"HDL participates in a process called [reverse cholesterol transport](_URL_0_) that can remove ~~plaque~~ cholesterol from peripheral tissue. As qxrt points out, this might not remove the plaque itself.",
"HDL carries lipids back to the liver and can reduce the rate of the plaque-forming process through reduction of inflammation and sequestering of cholesterol, but once the actual plaque forms, it becomes calcified, and it's relatively permanent. I only say relatively since it's likely that there are some processes going on that reduce the plaque (since most biological systems are in a constant state of flux, with opposing forces balancing out to create homeostasis).\n\nI'm personally not familiar with whether there's research to take advantage of any existing mechanisms of plaque breakdown, but current treatments involve either installing a bypass artery or busting open the artery, plaque and all, with a stent. There's no current treatment that removes the plaque itself. ",
"It really depends on how much plaque you have. Arteries can actually be partially clogged up to around 70% and you would still be fine (assuming you don't exert yourself too much) as certain arteries will enlarge or shrink in diameter to move blood throughout body properly. At that point, you may or may not want the plaque (usually calcified cholesterol and fat) to breakdown. If large pieces of plaque don't get dissolved, but stay in large chunks you might end up getting a stroke or a heart attack depending on where the plaque breakdown occurs. So in the case of stroke or a heart attack, blood is something in the human body that can breakdown plaque. \n\nNon-calcified fat may be reversible. Also it's important to realize plaques do not form everywhere in the arterial system. They generally occur in spaces with retrograde or stagnant blood flow. One reason why aerobic exercise is important is that it mechanically induces the epithelial cells in your blood vessels to produce more nitric oxide which prevents or inhibits fat from attaching to the arterial surface.",
"There are also ways to mechanically \"unclog\" arteries although their long term effectiveness rates are moderately low and patients often require repeat interventions to ensure that their arteries remain patent.\n\nPictures may be NSFL.\n\nOccluded arteries in the periphery (carotid, femoral, iliac, popliteal, etc) are treated through a variety of means. There are large \"open\" procedures to treat [occluded femoral arteries that often involve using vein or graft to establish flow](_URL_2_) or - [surgical dissection of the carotid artery](_URL_0_). \n\nOther-times, practitioners can approach an occluded vessel [percutaneously through an access catheter](_URL_1_) (of varying diameter, from 4french through 28french for some aortic stent grafts)"
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Reverse_cholesterol_transport"
],
[],
[],
[
"http://www0.hku.hk/surgery/vdc/CEA.jpg",
"http://interventions.onlinejacc.org/content/vol1/issue2/images/large/0800068X.gr2.jpeg",
"http://www.aafp.org/afp/2007/0101/afp20070101p85-f4.jpg"
],
[
"http://en.wikipedia.org/wiki/Reverse_cholesterol_transport"
],
[],
[],
[
"http://www0.hku.hk/surgery/vdc/CEA.jpg",
"http://interventions.onlinejacc.org/content/vol1/issue2/images/large/0800068X.gr2.jpeg",
"http://www.aafp.org/afp/2007/0101/afp20070101p85-f4.jpg"
]
] |
|
47bw1b
|
Can anyone please explain the difference between LUMENS and candela per square meter (CD/sqm) (In human language) as a measure of light brightness?
|
I am sourcing a product, a bicycle light. Have 2 options. One option has higher lumens (cheaper) but the other has higher CD/sqm (more expensive).
I am now having difficulty understanding the difference between lumens and candella per sqm. Which one is a better indicator of light quality/intensity?
|
askscience
|
https://www.reddit.com/r/askscience/comments/47bw1b/can_anyone_please_explain_the_difference_between/
|
{
"a_id": [
"d0byjng"
],
"score": [
3
],
"text": [
"A lumen gives the *total* amount of human-visible light given out. How bright the light actually is will depend on how wide the beam is. A very wide beam with a lot of lumens is as bright as a very narrow beam with a few lumens.\n\nA candela is maybe a more useful unit here. A candela tells you how intense the human-visible light is in every direction. It's independent of the size of the beam - it's basically the brightness \"per beam size\", if that makes sense. A 1 candela beam with a very small beam width looks just as bright as a 1 candela beam with a very large beam width. The both illuminate with the same brightness, it's just that one covers a bigger area than the other. So it's maybe a better unit for a headlight. Though it might not matter if all lights have similar beam-widths.\n\nHowever, \"candelas per square metre\" is a bit odd. As a unit, it makes sense, and it's something that we use in astronomy. It means something like \"the brightness in a specific direction per square metre of source\". That is, it's useless unless you actually know the size of the light source. I don't think that's the intent - it's probably mislabelled, and it really means just candelas.\n\nGiven that, it's quite likely that they're using the units incorrectly. So I wouldn't completely trust when they say \"lumens\" that they don't actually mean \"lumens\". Which isn't super helpful, I know."
]
}
|
[] |
[] |
[
[]
] |
|
7uy952
|
What were the predominant armor types worn in ancient southwest Asia?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/7uy952/what_were_the_predominant_armor_types_worn_in/
|
{
"a_id": [
"dto7vz7"
],
"score": [
4
],
"text": [
"The most common armour was scale body armour with a helmet of approximately conical or hemispherical shape. Surviving scales are commonly bronze, but bronze has an advantage in survival over rawhide and iron, which were also used. Descriptions of metal armour often describe it \"gold\" or \"silver\", which might refer to bronze and iron, respectively. Scale body armour could be either short, to the waist or hips, or long, covering to about knee level. Most armours appear to have been sleeveless or with short sleeves.\n\nNext most common would be lamellar, either short or long, and sleeveless or short-sleeved, like scale armours. Again, surviving lamellae are often bronze, but rawhide and iron were used too.\n\nMail probably appears in the region in late antiquity, and was in use by the early 3rd century AD. The first major users of mail in the area appear to be the Sassanids.\n\nThere are some armours with long sleeves for the arms, notably cataphract armours. Scale sleeves were used, and art suggest lamellar sleeves. Sassanid armoured cavalry would typically have long mail sleeves. Horse armour was also in use. I don't recall seeing mail horse armour, but both scale and lamellar horse armour were used.\n\nThere was some use of plate armour, from the mid/late first millenium BC. Body armour included round plates used to protect the torso, and more complete plate cuirasses, but these seem to be much less common than scale/lamellar/mail which appear much more often in art. Plate greaves were used; this was quite likely Greek/Hellenistic influence.\n\nH. Russell Robinson, \"Oriental Armour\" covers antiquity in the first chapter."
]
}
|
[] |
[] |
[
[]
] |
||
3gdrv0
|
why does raw seafood smell so much stronger than other animal proteins?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3gdrv0/eli5_why_does_raw_seafood_smell_so_much_stronger/
|
{
"a_id": [
"ctx82xd",
"ctx8rs8"
],
"score": [
3,
11
],
"text": [
" I'm definitely not an expert - but as there are no comments o will add my two cents.\n\nI think humans evolved to notice bad smells like raw meat, feaces, sour milk etc... as a defence mechanism.\n\nAlso some fish in markets and shops still have sea slime on them (normal thing for fish) this stuff stinks but is a good sign when buying fresh fish :)\n\nHopefully someone comes in with a better answer though \n\nSource: used to be a chef",
"Chemicals in fish digestive systems that break down food (ie: other fish) turn on the fish's own body when it dies, speeding up decomposition. This is why you're supposed to gut a fish asap.\n\nThe chemicals that cause the odor itself come from the decomposition and are called amines.\n\n_URL_0_"
]
}
|
[] |
[] |
[
[],
[
"http://humantouchofchemistry.com/why-do-fish-smell-when-you-buy-them.htm"
]
] |
||
2d1h2q
|
How did knights poop?
|
So say we have a fully suited up knight, all ready to go to battle, when he is hit by the sudden urge to take a dump.
Would his armor have flaps? Could the bottom be easily removed? Or did he just poop his armor?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2d1h2q/how_did_knights_poop/
|
{
"a_id": [
"cjlafp4"
],
"score": [
980
],
"text": [
"I'd like to make it clear before I post that I'm not an academic historian, however I've done a fair bit of reading on medieval arms and armour as I'm a practitioner of HEMA and re-enactment - I've also worn, sparred and occasionally even pooped in various types and combinations of chain and plate.\n\nBased on research by [Jones](_URL_3_) (2011), the term 'knight' has been used to describe a large and very diverse range of people. Medieval writers even referred to Julius Caesar and Alexander the Great as knights. I'm going to assume for the purposes of this answer that you're referring to knights in the sense of the martial elite of the middle ages/medieval period. The types of armour worn by knights between the 11th and 16th century varied quite dramatically - technological developments meant that armour changed significantly and quickly in that period. The precise types of armour that were commonly worn until the mid 14th century are hard to ascertain as pictorial sources are very open to interpretation - hardened leather and metal are difficult to differentiate from illustrations and this is compounded by the fact that fabric surcoats were commonly worn over armour, meaning that the armour underneath was seldom shown. Archaeological evidence also suggests that many knights used armour that was out of date - knights and men-at-arms, especially those who weren't very wealthy, commonly wore armour that was around 50-60 years old. \n\n\nEvidence on metallurgy technology suggests that metal plate armour wasn't in common use until the late 14th century. The chain/ringmail, padded clothing and leather armour preceding that wouldn't have been hard to remove if you needed to urinate/defecate. Operating under the assumption that when you refer to knights being 'suited up' you mean suits of plate armour worn by European knights and men-at-arms I'll focus on that. By 1400 or so metal plate armour began to be worn in the form of breastplates and faulds (articulated plate skirts) covering the torso, rebraces, vambraces and pauldrons covering the arms & shoulders, sabatons, greaves, cuisses and poleyns protected the legs and feet - all of these would have been attached to padded clothing worn underneath. The groin was still protected by a mail skirt - meaning that it could be easily lifted and padded undergarments pulled down in order to defecate.\n\nPlate armour of the type you're most likely thinking of was developed in the 15th century, when it diversified into Gothic and Milanese styles. Gothic armour emphasised mobility and flexibility with a more articulated design and used a mail skirt or underpants (braies) to cover the groin. Gothic gauntlets typically featured individually articulated plates for each section of the finger, meaning that the wearer would still have sufficient dexterity to lift up a skirt and/or pull down the padded cloth or chain underwear covering the arse. Milanese plate was typically heavier and less articulated, but still had a short, articulated skirt at the back meaning that the undergarment could be pulled down. Milanese 'mitten' gauntlets didn't have individually articulated fingers but wearers still retained dexterity as the finger and thumb plates were attached by a single leather strap just below the knuckle with a leather glove underneath (see [here](_URL_1_) for an example).\n\nIn the 16th century 'Maximillian' plate was developed - it was lighter, more highly articulated and sometimes [gorgeously decorated](_URL_5_). Gauntlets remained largely the same and plate skirts and codpieces became more common (chain was still used at the rear in some cases), although the arse was still accessible due to plated skirts being either flared or shortened at the back, meaning dropping trou and pinching one out could still be done relatively easily. By the mid/late 17th century plate armour was mostly obsolete due to firearms becoming more and more common.\n\nThe reasoning behind the derrière being so accessible in plate armour designs wasn't just to make taking a dump easier - in order for your legs to have proper freedom of movement you can't just strap a plate to it. Similarly, if you want to ride a horse (as was common for knights) then having metal plates between you and the saddle makes riding much more difficult and incredible uncumfortable. It would also make sitting down a rather problematic experience. Sources are Jones (as linked above), [Lawrence](_URL_4_), and [Clayton et al.](_URL_0_). If you're interested in medieval knights and their arms & armour then Jones is definitely worth a read. [This Channel 4 Documentary](_URL_6_) is also very informative and is really enjoyable; I highly recommend checking it out. \n\nWhen you're in a stressful situation (such as being in or gearing up for battle) then the body's adrenal response as a 'fight or flight' mechanism [stimulates your colon and rectum to contract](_URL_2_), meaning you're unlikely to need to drop a deuce when you don't have the time to pull up your skirt and drop trou. Accidents probably happened if the individual was experiencing 'digestive discomfort', but that's purely conjecture.\n\nThat's the limit of my experience and reading on the issue, I hope it helps!\n\n"
]
}
|
[] |
[] |
[
[
"https://www.wpi.edu/Pubs/E-project/Available/E-project-042008-164934/unrestricted/aa_final_document.pdf",
"http://i136.photobucket.com/albums/q162/davehyena/ArmourDraw/armordia.jpg",
"http://acccn.net/bio/book/bio50/lecnotes/lecnot26.html",
"http://brego-weard.com/lib/newosp/Osprey%20-%20General%20Military%20-%20Knight%20-%20The%20Warrior%20and%20World%20of%20Chivalry.pdf",
"http://www.abebooks.com/servlet/BookDetailsPL?bi=11455762171&searchurl=curl%3D%26%23x2F%3Bisbn%26%23x2F%3B0312307373%26%23x2F%3B",
"http://upload.wikimedia.org/wikipedia/commons/7/78/Medieval_armour_Vienna_museum.jpg",
"http://youtu.be/pqoh0okQ6Ho"
]
] |
|
1ve10k
|
When we mix two colors, do we create a new pigment, or are the colors still separate, just impossible to distinguish?
|
As in, if we mixed yellow and blue paint and looked at it under a microscope, would we see green paint? Or would we see tiny spots of yellow and blue, and no green?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1ve10k/when_we_mix_two_colors_do_we_create_a_new_pigment/
|
{
"a_id": [
"cerdsll",
"cerucbl"
],
"score": [
4,
2
],
"text": [
"Tiny spots of yellow and green. Paint mixtures aren't chemical reactions, there is no bonding. I mean, I can't speak to all paints, but oil, watercolour, and acrylic at least are all distinct pigments suspended in various solutions.",
"When the visible light hits a molecule, depending on what molecule it is, it will absorb a specific set of wavelengths of the light. The light that does not get absorbed will be reflected back, which is what we see. So the color of our subject is correlated with what wavelenghts that does not get absorbed.\n\nIn a mixture of 2 colors, some of the molecules will absorb some wavelengths, while the other molecules will absorb some different wavelengths. This leads to the change in color."
]
}
|
[] |
[] |
[
[],
[]
] |
|
34s6m7
|
Would you feel yourself spinning in absolutely empty space? If not, how is this possible?
|
I'm reading *The Fabric of the Cosmos* by Brian Greene and he's beginning to discuss absolute space. He mentioned how Mach said that if you were spinning in completely empty space with no reference points at all (ie. no stars or galaxies, no nothing), you would not feel yourself spinning even if you actually were. How is this possible? Wouldn't you feel the fluids in your body being pushed against wherever you are spinning toward, even if it's a very slight feeling?
|
askscience
|
http://www.reddit.com/r/askscience/comments/34s6m7/would_you_feel_yourself_spinning_in_absolutely/
|
{
"a_id": [
"cqxl7uy",
"cqxr567",
"cqxrpuy"
],
"score": [
10,
2,
7
],
"text": [
"Since spinning is a constant acceleration (constant change in velocity vector) the fluids in your ears should be displaced, and thus you should still be able to feel that you are spinning and get nauseous. If the spin is slow enough, I'd imagine that with zero reference points and a nearly non-existant fluid displacement, you wouldn't know you are spinning. ",
"There is an easy test you can do to check if you're spinning: get your arms and feet close to your body, then point them away from you. \nIf you're spinning this will change the rate at which you spin, caused by the conservation of angular momentum: Just like a pirouette in figure skating: _URL_0_",
"The problem with Mach's principle was more of a philosophical kind with regards to space itself. If we consider an empty unviserse, would it be possible to measure a rotation or not? It breaks down to \"is there an absolute space or not?\", because relative to an absolute space, one could measure a rotation/fictitious forces. \nAs others already pointed out, you would feel fluids in your body being displaced. In terms of \"how does this work out when there is no absolute space\": A rotating object in an empty universe would define a _global_ [metric](_URL_0_) different to the one of a non rotating object. It therefore should always be possible to find out if an object is rotating, which was pretty substantial to [Einsteins general relativity](_URL_1_):\n > Einstein realized that the overall distribution of matter would determine the metric tensor, which tells you which frame is rotationally stationary. Frame dragging and conservation of gravitational angular momentum makes this into a true statement in the general theory in certain solutions. "
]
}
|
[] |
[] |
[
[],
[
"https://youtu.be/VmeM0BNnGR0"
],
[
"http://en.wikipedia.org/wiki/Metric_tensor_%28general_relativity%29",
"http://en.wikipedia.org/wiki/Mach%27s_principle"
]
] |
|
10re9m
|
How long does light last for?
|
Does it degrade in any way, does its existence end or change when it hits a surface? What is light, what is dark?
I don't have any reason for asking this question, just wondering.
|
askscience
|
http://www.reddit.com/r/askscience/comments/10re9m/how_long_does_light_last_for/
|
{
"a_id": [
"c6fz6tn",
"c6g39xd"
],
"score": [
7,
2
],
"text": [
" > What is light,\n\nLight is what you perceive when a photon of light hits a photo-receptor protein in one of the cells in your eye. The protein gets energy from the light that prompts a conformaitonal change (it wiggles), and this wiggle causes a change in the rate-of-fire of the neurons in your eye. This signals (\"tells\") the brain that you have seen light.\n\nLight is made of little tiny particles called photons. All photons travel at the \"speed of light\", c, around 300,000,000 m/s. They travel at the speed of light from every frame of reference. So if you are moving towards the light, you still measure it moving at c. If you are moving away from the light, it is still moving at c, from your perspective.\n\nThere are an infinite number of different photons that can be created, because each photon has a specific \"energy\". There are high-energy photons and low-energy photons, and everything in between. High-energy photons are dangerous, and can cause cancer (gamma rays, X rays). Low energy photons are pretty much harmless (radio waves, visible light).\n\nAll the different energies of light lie on a \"spectrum\". Humans can only detect a narrow range of light energies, from red to purple. Red photons have less energy, green have an in-between amount, and purple has the most. Above purple is ultraviolet (higher energy). Below red is infrared (low energy).\n\n{Humans glow. We emit photons. But these photons are low-energy infrared photons, which humans can't detect. So we can't see ourselves glow. But snakes can detect infrared photons. So snakes can see us glow!}\n\n > what is dark?\n\nDark is a human/animal perception. It occurs when no light hits the sensory apparatus (the eye).\n\n > Does it degrade in any way\n\nYes and no. When it is travelling through empty space, light does not have an expiration date. We can look in the sky and see photons from 1 billion years ago. It is only when light hits and interacts with an object that it changes. Light can be absorbed and converted to heat. Or converted to energy (as in solar cells or plants doing photosynthesis).",
"Light doesn't degrade in any way - powerful telescopes can be used to see objects at the detectible edge of the universe, approximately 13 billion light years away (and thus the light took 13 billion years to reach earth)."
]
}
|
[] |
[] |
[
[],
[]
] |
|
2ahoyc
|
Is it possible to have multiple earth like planets in a planetary system?
|
Can a planetary sytem have like 4 earth type planets each planets having his own ecosystem and able to sutain life?
|
askscience
|
http://www.reddit.com/r/askscience/comments/2ahoyc/is_it_possible_to_have_multiple_earth_like/
|
{
"a_id": [
"civk5xp"
],
"score": [
6
],
"text": [
"It really depends on the planets. Venus and Mars are both within the \"Goldilocks zone\" for Sol. Depending on who's math they are right on the edge though. Venus ended up with a runaway greenhouse effect and now has an acid atmosphere, Mars lost its magnetic field and was stripped of its atmosphere. At one point, both of those planets were quite similar to earth so it can be done.\n\nThe safe zone isn't a single orbit, it is a rather wide area so you could easily sneak a couple planetary orbits in there. There are billions of stars out there, anything that can exist almost certainly does exist, we just haven't found it yet."
]
}
|
[] |
[] |
[
[]
] |
|
cczczz
|
how come seedless cherries aren’t a thing like seedless grapes and oranges?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/cczczz/eli5_how_come_seedless_cherries_arent_a_thing/
|
{
"a_id": [
"etqelan",
"etqt063"
],
"score": [
6,
4
],
"text": [
"The \"seed\" in a cherry is called a pit, and if I'm not mistaken, it's where the juicy part of the cherry came from. Similar to dates and plums. In contrast, the seeds of grapes and oranges are intended to produce more grapevines/orange trees",
"Because no one has been able to figure out how to create one.\n\nThe same applies to all other stone fruits, like apricots, plums, peaches, etc."
]
}
|
[] |
[] |
[
[],
[]
] |
||
1uvbja
|
The maya treated the lower classes extremely poorly for over 2000 years, why was there no successful rebellion?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1uvbja/the_maya_treated_the_lower_classes_extremely/
|
{
"a_id": [
"cem23py"
],
"score": [
3
],
"text": [
"Can you elaborate? In what way do you think the Maya lower class was mistreated (and consistently for so long at that)? Is there some particular piece of evidence that led you to that conclusion?"
]
}
|
[] |
[] |
[
[]
] |
||
37eyzz
|
Is temperature vary based on the point of reference?
|
I saw an article on bbc today about things falling into black holes and burning up to an external observer amongst hawking radiation. However, it made me wonder if that means that temperature, which is a measurement of energy density is only high because of spatial compression as the object approaches the speed of light, and that in the object's frame of reference, it appears much larger and cooler? It would seem that everything near the event horizon would naturally be close in temperature to that at their entry into their terminal flight within it's frame of reference, and as such, there probably isn't a lot of energy transfer between the seemingly equally hot objects heading towards their destination.
|
askscience
|
http://www.reddit.com/r/askscience/comments/37eyzz/is_temperature_vary_based_on_the_point_of/
|
{
"a_id": [
"crmbyf4"
],
"score": [
3
],
"text": [
"Good question, and yes. We understand the asymptotic Hawking temperature, it becomes a constant for sufficiently distant observers at rest. In simplified units it takes on the form, \n\n T = k/2pi \n k = surface gravity at event horizon \n\nLet's look at Schwarzschild coordinates, \n\n ds^2 = -(1-R/r)(cdt)^2 + (dr)^2/(1-R/r) + angle terms \n R = Schwarzschild radius \n\nThis corresponds to a frame which \"hovers\" above the black hole at a fixed radius, as you can see the temperature is modified by the curvature, \n\n T = a/2pi = (k/2pi)/√(1-R/r) \n\n* Unruh. [\"Notes on black hole evaporation\"](_URL_1_) Phys.Rev. D14 (1976) \n\nHere we see, the hovering temperature relies on the inverse of the square root of the curvature. There are two important features:\n\n1. As you recede to flat space r-- > big, you recover the famous Hawking temperature. \n\n2. As you approach the Event Horizon of the black hole, the temperature blows up to infinity. We can attribute this to the acceleration an observer must maintain to not fall into the black hole.\n\nWhat about free falling into the black hole? Like if I decided to jump in? Unfortunately, I could not find an exact mathematical treatment--except to say that there is an exact solution for 6-dimensional spacetime. \n\n* Brynjolfsson, Thorlacius. \"Taking the Temperature of a Black Hole\" JHEP 2008. _URL_3_ \n\n* Kim, Choi, Park. \"Local free-fall Temperature of GMGHS Black Holes\" Phys. Rev. D 89. 2013. _URL_2_ \n\n* _URL_0_ \n\nAll these suggest that the free falling observer will see a finite radiation bath (which isn't precisely thermal) on the order of the Hawking temperature even as they cross the horizon--so they won't burn up!"
]
}
|
[] |
[] |
[
[
"http://physics.stackexchange.com/a/22952",
"http://www2.lns.mit.edu/fisherp/Unruh.pdf",
"http://arxiv.org/abs/1311.0592",
"http://arxiv.org/abs/0805.1876"
]
] |
|
14atnx
|
Why can't we run 64 bit applications in a 32 bit operating system, even if the CPU supports 64 bit?
|
askscience
|
http://www.reddit.com/r/askscience/comments/14atnx/why_cant_we_run_64_bit_applications_in_a_32_bit/
|
{
"a_id": [
"c7bh2ae",
"c7bh9r5"
],
"score": [
10,
6
],
"text": [
"A 32 bit operating system running on an x64 processor causes the processor to run in a 32-bit mode. For example, it uses 32-bit addressing in its virtual memory system.\nSee for example: _URL_0_",
"The application (64-bit) has to go through the software layer (32-bit) before it communicates with the hardware (64-bit)."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/X86-64#Operating_modes"
],
[]
] |
||
1p6vm1
|
Why do rivers meander?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1p6vm1/why_do_rivers_meander/
|
{
"a_id": [
"cczj24z"
],
"score": [
6
],
"text": [
"I'm not an expert but...\n\nWater takes the path of least resistance. So if the ground is lower in one spot vs another, that is the direction the river will take. Or if the ground is softer or more prone to erosion, that will help to guide the path of the river.\n\n\nOnce the river is bent, the erosion will be strongest on the outside of the curve, which will cause the curves to become more and more pronounced over time. "
]
}
|
[] |
[] |
[
[]
] |
||
9rzw9h
|
why is a vehicle released in (for example) 2018 called a 2019?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9rzw9h/eli5_why_is_a_vehicle_released_in_for_example/
|
{
"a_id": [
"e8kzsbo",
"e8kzzdc",
"e8l1isz",
"e8ll8kd"
],
"score": [
12,
5,
24,
2
],
"text": [
"Because retail products need to appear new. Since the 2019 model will be the \"new\" model for some portion of the 2019 year, you don't want people asking, \"this is last year's model, where is this year's?\" If it's marked 2018 as it may disincentivize them from buying.",
"It's because people are less likely to buy cars with the previous year in the model name, so they name cars after the next year. It's not just cars. For example, Magic the Gathering's Core Set 2019 was released on July 13, 2018. Major retailers like Walmart are less willing to stock items with the previous year in the item's name.",
"There isn’t really a singular reason rather a few different things that led to it. \n\nFord started releasing the next year’s model in the fall for those in agriculture. That was when they had the most money so they released the model at a time that people could buy next year’s model instead of buying the almost year old current year model. \n\nOther companies followed suit and started releasing in the fall, after WWII they settled on Oct 1 for an industry standard. \n\nJumping to the 60s this also coincided with the rising television industry’s start of the fall season which always sees a spike in viewership which meant more people seeing ads",
"It's a marketing scheme.\n\nIf you want to produce as many cars as possible in 2019, you'll have to let out a teaser on the market in 2018 already. Else, you'd have a pretty dull January in the factory while everyone runs to the dealer, decides and signs up for one to be delivered sometime in February/March.\n\nGenerally speaking, the manufacturers *could* just release their new model \"sometime around summer\" and say \"this is the New Car With Large Hatchback that supersedes the older Car With Hatchback we sold last year*, but many people tend to think of new in terms of \"is it related this year? No. Then it ain't new\" and you have to adapt to that a bit to survive on the market."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
5k4y3c
|
who controls the internet?
|
Is there anyone that monitors the Internet to make sure there are no illegal things going on, such as sales of weapons, skimming devices, etc? A friend told me that the US government controls the internet because they created it. Is that true?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5k4y3c/eli5_who_controls_the_internet/
|
{
"a_id": [
"dblbc9w",
"dblbowh",
"dblfelt",
"dblk345"
],
"score": [
10,
94,
7,
12
],
"text": [
"Officially, no, no one controls the internet. With no primary head server & formal control of the internet now ceded to ICANN (a non-for-profit private company) instead of the US government, the US government is relatively lacking in direct methods to police the whole thing.\n\nHowever, plenty of technology is still *physically* within US and therefore under jurisdiction, and they can and do attempt to monitor traffic. US companies have to comply with US law, and they have been made to hand over information from their servers. Additionally, the US has data collection and montoring methods. How successful they are varies due to tools like encryption being used, but the government certainly tries.",
"Short answer is \"no\" on both accounts. \n\nLonger answer is that yes, there is monitoring on many levels of the internet that is maintained by agencies and law enforcement as well as by NGOs and lobby organizations. \n\nA government agency is unlikely to care that you're torrenting, but will care if you're making terrorist plots. Law enforcement will likely not care about your torrents either, but will care if you run a pedophile ring, and NGOs such as the MPAA will very much care about your torrenting, but they ahve very limited access to the internet. \n\nThe US government does not control the internet. It isn't unlikely that they exert greater control than they let on through surveillance , as indicated by the last few years' leaks, and them asking corporations to install backdoors in software. \n\nThe US did not create the internet either, really. They _did_ create ARPAnet, which is a predecessor and have had a great hand in shaping and developing the internet, or at least universities have, but the greater question is \"what is the internet\", which makes things more complicated. \n\nThe internet is many things. The internet is infrastructure - It is radio towers to distribute wifi and cables to run ethernet through, some of them transcontinental and transoceanic. \n\nThe internet is hardware - It is routers and switches and modems and servers\n\nThe internet is also software, with applications, sites, server software, DNS, storage, databases. \n\nMany of these layers and segments are distributed, and none of them are government controlled - Most are controlled by working groups and organizations that work with maintaining and developing standards, and more hands-on with private companies who manufacture and support the hardware and software which runs these things. \n\nTo reconnect to your first question: Yes, there is monitoring by agencies and law enforcement to hinder illegal activities such as trade with drugs, weapons and people, wire fraud, financing or plotting terrorism etc, but it's not one single entity that monitors the entire internet for it, rather government agencies and law enforcement that all work according to the laws and interests of teir nation (or the EU, or NATO, or whatever), with collaboration where possible and necessary. \n\nThis also involves a lot of real-world work as well, monitoring people, suspects, their activities, working to establish links between online personae and real-world people etc. ",
"The internet is a semi-organized collection of computers that are all interconnected with each other in various random ways. Decisions about how those connections should work are made unofficially by popular consensus. Decisions about how each computer should work are made by the owner of each computer.\n\nNobody directly controls the entire Internet, in the same way that nobody controls all the roads and highways and cars and boats and trains and airplanes in the world, but you can still travel anywhere you want.",
"No one person owns the entire Internet. However, the entity that \"owns\" the largest chunk of the web is Google. One time when *all* Google products (Google Search, Gmail, YouTube, Drive, Docs, et cetera) stopped working for **five minutes**, global internet traffic dropped by a staggering **40%**. Since so much internet traffic is with Google products, it's safe to say they \"own\" more of the Internet than anyone else.\n\nHope that was a satisfactory answer :D\n\n^(*All Google products shall perish from under the sky*)\n\n^(*Reddit alone shall live*)\n\n^(*Reddit alone shall live*)\n\n^(*Never to die*)"
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
|
4rs97q
|
What elements/compounds give Jupiter its colors?
|
The atmosphere is mostly hydrogren and helium, with some trace elements. What gives color to those swirling bands?
|
askscience
|
https://www.reddit.com/r/askscience/comments/4rs97q/what_elementscompounds_give_jupiter_its_colors/
|
{
"a_id": [
"d53yrrv"
],
"score": [
21
],
"text": [
"**The short answer**: Hydrocarbon hazes, Rayleigh scattering, and some unknown compound.\n\n**The long answer**: For the primary whites and browns that cover most of the planet, you need to realize that almost everything you see when you look at Jupiter is ammonia clouds, which on their own are bright white. Some latitudes are regions of upwelling (zones), and have high ammonia cloud-tops, while other latitudes are regions of downwelling (belts), and have low ammonia cloud-tops. In between these high and low heights sits a thick brown hydrocarbon haze, very chemically similar to smog. The cloud-tops in the zones are sticking up above most of the haze and thus appear fairly white. The cloud-tops in the belts, though, lie below the haze layer, and thus appear colored brown by the overlying haze.\n\nFor the occasional bluish regions seen just to the north and south of the equator, these are some of the rare cloud clearings that occur in very strong downwelling regions. We're actually peering through the ammonia top cloud layer, and perhaps even down through the ammonium hydrosulfide middle cloud layer and the bottom water cloud layer. So, in those regions we're looking at just clear air, which has the exact same color as it does one Earth, blue. This is entirely due to Rayleigh scattering, the same reason that Earth's sky is blue.\n\nThen there's the reds, notably in Jupiter's Great Red Spot, although also occasionally seen in another big vortex here and there. As of right now, we don't actually know what makes the Great Red Spot red - this is generally known as the Jovian chromophore problem. Since this color is only seen in very large vortices, it's believed to be caused by some mixture of compounds already present on the planet getting pushed very high in the atmosphere by these vortices. In three dimensions, the Great Red Spot is essentially shaped like a wedding cake, so the cloud-tops at the center of the spot are at very high altitudes where there's a lot more ultraviolet light. You can end up producing all kinds of odd substances through UV photochemistry of trace substances in the atmosphere, and the working hypothesis at this point is that it's some kind of imine."
]
}
|
[] |
[] |
[
[]
] |
|
2pulaz
|
how did spacex develop rocket technology so quickly?
|
I flaggerbasted at the speed with which SpaceX is developing rocket technology, because it's taken many countries(including USA, Japan, France), several decades to perfect rocket technology.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2pulaz/eli5_how_did_spacex_develop_rocket_technology_so/
|
{
"a_id": [
"cn05qjo",
"cn05s88"
],
"score": [
4,
3
],
"text": [
"It's not like they're starting with the same technology as nasa when it was founded.",
"SpaceX was working directly with space agencies, building on top of the technology and knowledge-base that had already been developed over many decades. Rather than re-inventing the wheel, they stood on the shoulders of giants (so to speak)."
]
}
|
[] |
[] |
[
[],
[]
] |
|
95yjal
|
Why were the Turkish states able to assimilate Anatolia so quickly? Why didn't Persia or the Balkans assimilate?
|
I understand that the process was not quick and it consisted of suppression of minorities, Turks had greater economic and political opportunity. However, why did this only happen in Anatolia (particularly the Eastern part)? Why didn't this happen in Persia where the Seljuk Turks ruled for over a century or in the Balkans/Mesopotamia under the Ottoman Turks?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/95yjal/why_were_the_turkish_states_able_to_assimilate/
|
{
"a_id": [
"e3wobgt"
],
"score": [
12
],
"text": [
"I'll start off my answer by pointing out that significant parts of Iran and Afghanistan were in fact Turkified; Azerbaijan, parts of Fars, northeastern Iran, and northern and central Afghanistan. The main reason this happened, I would argue, is that the climate and habitat of these regions were (similarly to Anatolia) suitable to Turkish nomads. [I'm not too knowledgeable on Ottoman rule in the Balkans, so I'll leave that to someone else.[Though I would hazard a guess that Ottoman government was considerably more sedentary than their earlier Turkic colleagues and so were less concerned with the settlement of migrating Turkic tribes.]]\n\nThe reason for this suitability lies in the mix of mountainous and flat terrain. The Turkic nomads who invaded Iran from Central Asia, and eventually moved further into Anatolia, practiced vertical transhumance. This involved the seasonal migration of the nomads' animal herds: down into the valleys/plains during the winter, and up into the lower reaches of the mountains during summer. \nThe reason for the noticeably smaller degree of Turkification in Iran and Afghanistan compared to Anatolia is due to the presence in Iran/Afghanistan of competing groups. Kurds, Lurs, Pashtuns and many other Iranian groups already engaged in forms of nomadic pastoralism and so would have provided competition for space with the incoming Turks. \nAnatolia on the other hand, was populated mostly by urbanised, sedentary Greeks, Armenians, and Syriacs. There likely were some native nomadic groups, but certainly not to the same degree as Iran and Afghanistan. Consequently, the migrating Turks faced relatively little competition during their settlement of Anatolia.\n\nThere were obviously other factors involved, such as the power vacuum in Anatolia after the Battle of Manzikert as the regional nobility fled to Constantinople to take part in the Byzantine intrigues (pun definitely intended) to select a new emperor, or in the remarkable ability of these Turkic tribes to assimilate Islamic and Christian ideas into their pre-existing pagan-influenced governing ideology. However, to reiterate it is the suitability of the terrain that I find to be the most important factor in the Turkification of these regions."
]
}
|
[] |
[] |
[
[]
] |
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