query stringlengths 20 300 | positive listlengths 1 1 | negative listlengths 1 1 |
|---|---|---|
How do we know that gas giants are made purely out of gas? | [
"We *don't* think that gas giants are made purely out of gas... The current theory for most giant planet formation is the [core accretion theory](_URL_1_). Basically, if you happen to build up a rocky planet of ~10x Earth's mass before the gas in the accretion disk dissipates, then that planet will start to accrete... | [
"They use [Doppler spectroscopy](_URL_0_) to determine the relative motions and period of the star and planet. [Orbital mechanics](_URL_2_) then gives the mass ratio of both. Edit: [Dannei's comment](_URL_1_) is a far more complete and instructive answer to this question."
] |
Why does hot water rise and cold water sinks but ice floats? | [
"Ice is less dense than water, due to a quirk of its molecular structure. When water freezes its molecules form ring structures, increasing the volume without increasing the total mass. This reduces density, and since objects less dense then the liquid they're in float, ice floats."
] | [
"Europa is very far away from the sun, past a region called the ice line. The ice line is the region beyond which water (and a few other volatiles) can survive in clumps, and won't be broken up by the sun. Where Europa was forming, there was a lot of icy material around for it to accumulate and hold on to. Where Ea... |
Does the use of microwave ovens distort chemical structures in foods resulting in toxic or otherwise unhealthy chemicals? | [
"Yes, microwave ovens distort chemical structures in foods. The heat from the microwave energy causes proteins to uncoil and change their shape, causing their texture and flavor to change. This phenomenon is known as \"cooking\", and is the same whether you microwave, boil, bake, or fry food."
] | [
"Basically, the nukes we dropped on Hiroshima and Nagasaki were very small nukes (compared to what we have at our disposal today) and, while they DID cause radioactive fallout, they caused a (relatively) small amount of it, and it is no longer dangerous to live there - but it WAS dangerous for many years after the ... |
Why is it movie theater popcorn tastes so amazing no matter where you are? | [
"Movie theater popcorn is typically made with an additive called flavicol, which amps up the buttery taste. It’s nontoxic, despite its ominous name, but is the source of that uniquely rich flavor that movie theater popcorn seems to possess."
] | [
"They all have a slightly different composition, the temperature and amount of oil also differs depending of the location of the kernel in the pan. The pan doesn’t distribute heat evenly."
] |
Why do people usually sneeze two times in a row ? | [
"Sneezing is a reaction to clear out your nasal passage when there is an irritation in the nose. Sometimes that irritation is not gone by the first sneeze, so your brain will continue to tell your body to sneeze."
] | [
"Have you ever gone to open a file on your desktop? Open up a file in your hard drive? All of those require double clicks. And now that I said that, I think you might be referring to then constantly clicking something after the first double click. My suggestion? They're just old and don't realize they already click... |
How big are human intestines and why? | [
"The small intestines is about 20 feet long while the large intestines is generally about 5 feet long. The main purpose of the intestines is absorption of nutrients and water from your diet. To do this, you must expose whatever food or drink you have ingested to the enzymes (which facilitate absorption) lining the ... | [
"Have you ever loaded a 4K UHD YouTube video on a 1080p device? Well, 3840x2160 has exactly 4x the amount of pixels as 1920x1080, so what happens is that every 4 pixels (imagine a 2x2 square) gets made into 1 pixel, the color of that pixel is the average color of all 4 pixels. Photos are more difficult as they ha... |
How influential was Reagan in ending the Cold War? | [
"Although Gaddis makes some good arguing points in Strategies of Containment, I really feel as if it wasn't so much Reagan as it was Gorbachev's recognition of their failing economy and his personality in general. While Reagan was busy building the Space Defense Initiative and doing pretty stupid things like Able A... | [
"From _URL_1_ : ''2.9 Argument from Extra-Sensory Perception The strangest part of Turing's paper is the few paragraphs on ESP. Perhaps it is intended to be tongue-in-cheek, though, if it is, this fact is poorly signposted by Turing. Perhaps, instead, Turing was influenced by the apparently scientifically respectab... |
If wikileaks is a threat to corruption/collusion in developed countries, how is it still up or not constantly attacked? | [
"A DDOS attack works by bombarding a website with so many commands that it has to shut itself down. It's effective if you have enough computers to do it, but the bigger the site, the more computers it takes to shut it down. It's also illegal to do a DDOS. It would be difficult for a government to do that without ge... | [
"Hi there -- while we've approved this question, we would like to remind potential respondents of our [current events](_URL_0_) (AKA \"20-year\") rule -- it's fine to discuss events through 1997 (inclusive) and their effects, but not events after 1997. Thanks!"
] |
Why is a mini gun called a mini gun when it obviously a fairly large gun? | [
"They're \"mini\" when compared to other guns with the same firing mechanism. [M134 Minigun](_URL_0_) vs. [M61 Vulcan](_URL_1_)"
] | [
"Simple: Their music doesn't act as a confession. Music is a performance, you wouldn't arrest an actor for being a murderer just because they play one in a movie would you? Similarly you wouldn't arrest Eric Clapton for admitting he shot the sheriff, and you can't arrest a rapper for saying they are \"ridin' dirty\... |
Why is Lake Baikal so deep? | [
"It's situated in a continental rift, an area where two tectonic plates are slowly moving apart (think of places like the mariana trench). The result of this is a very deep rift in the crust of the earth, which in this case filled with water."
] | [
"_URL_0_ 'December 2012 marks the conclusion of a b'ak'tun—a time period in the Mesoamerican Long Count calendar which was used in Central America prior to the arrival of Europeans.' ELI5 translation: End of the mayan calander, about as much significance as reaching the end of your calender. Everything to do with i... |
Why do ears ring when your sitting around doing nothing and ring louder when concentrating on the ringing? | [
"Most people would say tinnitus. But I believe that this can also occur without tinnitus as well. Same principle as when you close your eyes and see lights and shapes. When presented with a lack of stimuli to one of your sensory organs, your brain will make it by itself. So when presented with near perfect silence,... | [
"It's called [mind-wandering](_URL_0_). It's long been thought that the [default mode network](_URL_1_) is what drives this. This network refers to a number of regions in the brain which show greater activity when people are not engaged in any active task (or are engaged in an easier relative to harder task). The i... |
Why is it easier to parallel park in reverse? | [
"Because most cars steer with the front wheels. So if you are reversing into a spot, you 'set' the rear of the car in the spot and maneuver the front end of the car to be parallel to the curb. If you are trying to park while driving forward, you can maneuver the front end of the car into the spot, but there's no wa... | [
"Simply put for the same reason drinking water when you're not thirsty isn't as refreshing as when you're REALLY thirsty. Anticipating the bodies' needs doesn't trigger the same reward responses in the brain as fulfilling a need that is already present. Your muscles don't NEED to stretch right now, so you can't ant... |
why is there never a "wind chill" (seperate from when a thunderstorm/hurricane approaches) in the summer? i.e., it regularly is 35 but "feels like" 20, but i never hear "95 today, but will feel like 80." | [
"My understanding is that these values typically act as outside measures (max and min). During the summer you would have a high of X which would be augmented by the humidex to a higher value. During the winter, we usually see a wind chill augmenting a negative value (Celsius) to a more negative number. I would imag... | [
"The SPF number refers to how much of the incoming UV light will make it to your skin when you apply the cream properly (which is, according to wikipedia, 2 mg/cm^2 ). So with SPF 15 you receive 1/15 of the UV, with SPF 30 you receive 1/30, etc. This means that the necessary exposure time to get a burn is increased... |
Beyond shape, does the texture of an airfoil's upper surface change lift? | [
"Ice causes the effect you are speaking of: _URL_0_ > The most significant effect of snow or ice on the wing surface is its influence on the smooth flow of air over the surface contour. Changes in the contour shape and roughness of the surface will cause the airflow to begin to separate from the wing at a lower ang... | [
"Pilot here...Pilot reports are really the best way to know when it will be bumpy. One plane 100 miles ahead will report turbulence at a certain altitude to ATC and then they will relay the message to other planes. Those other planes can then decide if they want to deviate course or altitude...Also just don't fly i... |
if moths ate attracted to light why don't they come out during the day? | [
"They're not attracted to light. They use the sun and the moon to navigate, trying to always keep it to one side of their vision so they know where they're going. It's when it's dark and we have bright artificial light sources, such as a porch light, that the moth tries to constantly go \"oh crap, gotta keep it on ... | [
"Do you have a fly screen over the window? If so what you are observing is a [Moiré pattern](_URL_0_) being projected onto the window. Essentially the light is passing through the screen and the light waves get split up and then interact with each other causing spots of superposition where some regions are darker a... |
Does what I believe (or know) influence how my immune system reacts to things? | [
"The belief, in and of itself, isn't really as consequential as its effect on your physiology. Any anxiety or stress induced by your belief that alters your mood can have very real psychosomatic effects via hormones, stress chemicals, or other means. For example, if you are worried enough about something to actuall... | [
"Its been shown that the placebo effect still works even when the subject is fully aware that they are only receiving a placebo drug. _URL_0_ Obviously its something that needs more study to be understood but the placebo can actually work."
] |
If the American middle class is dying then who's buying all the middle class stuff out there? | [
"Toys and luxuries don't matter. The important and biggest purchase for a middle class family to make is LAND. Home ownership is one of the best investment to make, but with skyrocketing prices in most cities, hey are unable to afford it. New home purchases now is HALF what it was 10 years ago. _URL_0_"
] | [
"Because the growth is: * In part comprised by a rising population which doesn't impact median wages. * Captured mostly by high earners rather than the median earner."
] |
How 'peaceful' was the Middle East prior to the Gulf War? | [
"Not very. Off the top of my head and this is mostly from 1945 on. 1. Arab Israeli War of 48 2. Egyptian Revolution of 52 3. Iranian Coup of 53 4. Suez Crisis of 56 5. 1st Kurd-Iraq war of 61 6. Six Day War of 67 7. Iranian Kurd revolt of of 67 8. Yum Kippur War of 73 9. 2nd Kurd-Iraq War of 74 10. Lebanese Civil W... | [
"Is [this the article](_URL_0_) you are talking about? If so, it is a pack of lies. I don't have time to go through the whole piece, but the first two \"signs\" are both wrong. Lie #1 - The world **is** warming. There hasn't been a \"halt\" in warming since 1998. March of this year marked the [337th month in a row]... |
When howling is heard, why does wolves have the need to howl back? | [
"Howling is done for communication. Imagine if you heard someone yelling \"Is there anyone out there?\" your instinct is to respond. It's why you can get wolves to howl if you howl towards them. They think you are trying to communicate."
] | [
"I think it might have some base i historical gender roles. The women in the village,cooking,weaving,yapping and watching the kids while the men are on the hunt,completely focussed on the kill/trail."
] |
Due to the (Newtonian) gravity equation, wouldn't heavier objects technically fall faster? | [
"Yes, there is a very small correction to the falling due to the fact that the smaller object is pulling the larger one towards it. It is approximately m/2M. If M is the mass of the Earth, and a person with m=100 kg is falling towards it, your naive estimate that the person's mass doesn't matter will be incorrect b... | [
"Think about things bouncing around. Imagine a box with a fan in it. Put 20 balls in ithe box. Now imagine a basket to one side just the right size for the balls. Turn on the fan. The balls jump around randomly. At some point a ball will fall into the basket. This will happen at a given rate which will depends on h... |
Why does hot tap water look cloudy, while cold tap water is clear? | [
"You probably have a combi boiler -- my husband and I moved into a new build place and we were slightly freaked out the first time our hot water came out cloudy. The only time water comes into contact with air in those types of heaters is at the tap, and apparently it's all to do with the calcium bi-carbonate in th... | [
"Your faucet has a screen on it sometimes referred to as a diffuser. If you unscrew the diffuser from the end of the faucet, that probably won't happen anymore."
] |
If a bite from a human requires a visit to a doctor because of the bacteria, why, if we were to lick our own open wound, does not the same risk apply | [
"Our *natural* bacteria in our mouth has no threat to us. And our saliva has beneficial properties on wounds. However, if someone else bit you, who the fuck knows what illness he could have. If the person who bit you was perfectly healthy I don't think it would be a problem. But would you just take his word for it... | [
"The foods one I can answer. We evolved to like high caloric foods because we needed the calories when we were struggling to survive. Thus fatty or sugary foods taste good to us because it used to be great to eat them. Well now it's too easy to overindulge and weve made processed foods that have way more fat or sug... |
Black holes lose mass due to Hawking Radiation, does this mean that all mass captured by a black hole turns into pairs of virtual particles to be radiated away? | [
"> Let's say i shoot a rocket towards a black hole and it gets sucked up, will the mass of that specific rocket be eventually radiated away? Yes, everything they capture will radiate away. But it is **REALLY** slow proces. Black hole which is as heavy as our Sun would radiate all its energy in [2×10^67 years.](_URL... | [
"Ultimately this is going to come down to how you define the mass of light. The sort of standard definition would the \"rest mass\" or \"invariant mass\". This is defined in terms of four-momentum of the system under consideration. Specifically, if the four-momentum is (E/c, **p**) where E is the energy of the syst... |
Wednesday What's New in History | September 28, 2016 | [
"It didn't happen this week, I just discovered it this week. Sekigahara is getting the Nagashino treatment. That is, there's a movement among Japanese scholars to re-examine the battle and the sources used to traditionally describe it, focusing on sources closer to the event questioning later sources. Some of it I ... | [
"Hi everyone. Since this is the kind of question that can attract non-expert responses, just a friendly reminder that all responses must comply with [sub rules](_URL_0_), and that [personal anecdotes](_URL_1_) are explicitly not permitted in /r/AskHistorians."
] |
Why are there suddenly "guardrail famage ahead" signs everywhere? | [
"You drive small car. You don’t need the signs. I drive big truck. I see sign. I may have to readjust my steering. Or maybe not. It just nice to have a sign in case it’s an issue"
] | [
"This is from 2008: _URL_0_ Better deal to buy nationwide advertising instead of of a regional area, and it can build hype up. I know where I grew up, they built a Sonic and it was popular at first, no it's not the south either."
] |
I found this weird skull (I think) on the beach in Northern California, can anyone identify it? | [
"That is a pelvic bone (or rather, the fused bones that form the pelvic girdle). In your third picture, see how the front looks like a vertebra? That's because it is (leaving out some biological detail). Those large holes which sort of look like eye holes are obdurator foramena, and the little holes along the back ... | [
"The first 100 issues of an important UK archaeology monograph series, East Anglian Archaeology, were recently made available [for free on their website](_URL_0_). These are site reports - publications of archaeological data - for the UK counties of Norfolk, Suffolk, and parts of Cambridgeshire. The series includes... |
If some online stores use bitcoin as a payment method, are they obliged to pay taxes, since no 'official' currency exchange has happened? | [
"I assume you are in the US. Business and individuals are responsible for income taxes on income from any source, even barter. Sales taxes are state and local government specific so I don't know if there's any technicalities in any jurisdiction that could get the business out of charging for those, but I doubt it, ... | [
"\"Youtube to MP3 sites don't commit piracy, people commit piracy.\" That is, their function isn't inherently illegal, but people do tend to use them for illegal actions."
] |
Did Native Americans cross the Atlantic in 60 B.C? | [
"Not to discourage any more information on this topic, but FYI, this question came up before: [What Pre-Columbian new world contact scenarios do you support (if any)?](_URL_0_)"
] | [
"Follow up. Would they be able to figure it out considering the travel times involved in traveling between the hemispheres back then?"
] |
Why does mac-n-cheese not taste cheesy after you reheat it? | [
"So macaroni and cheese changes when it gets cold in a few different ways. The oils in the cheese sauce get cold and harden up and separate, while the macaroni continue to absorb more water. Some water is also lost if it isnt in an air tight container. This turns what is left into a starchy and oily mess. You can r... | [
"they have different density (amount of mash potatoes per volume is higher than beans?) and different heat capacities (how much energy is needed to raise the temperature by a given amount). The most important factor is most likely water content, microwave ovens work by heating up water within the food, the more wa... |
What mechanism prevents hernias from healing on their own and necessitating surgery? | [
"Hernias are like when you have a hole in your shirt and you keep playing with it. It only makes the hole bigger. The body doesn't have a mechanism for pushing the bits that are sticking out back in and sealing the hole up automatically."
] | [
"It's the same as any other business really. People stop going and businesses pull out because it's no longer profitable. And it causes a feedback reaction becauses as businesses pull out, fewer and fewer people will have reasons to go."
] |
Why is a week made up of seven days? | [
"The seven day week is chosen because of the 28-day lunar cycle. Every 28 days, there is a new moon, which is really visible - when you first see a moon at sunset. This makes dividing time into lunar months obvious (By the way - moon/month. Yes, that's where the word comes from.) Dividing that lunar cycle into 4 ju... | [
"This CGP Grey video does a really good job of explaining it all. _URL_3_"
] |
Some events (quantum scale) are known to be truly random, not deterministic. How do we infer that they are really random? | [
"By some quantum events I assume you are referring to measurement outcomes on quantum systems. These are not known to be truly random. Whether or not you call them random depends on your interpretation of quantum mechanics. From an operationalist point of view (i.e., I only care about experiments and not what is g... | [
"Well one way is by selected specific people for your study. The studied that showed evidence that vaccines caused autism actually dropped people from the study who had children not become autistic, found children who had family history of autism to include in the study, and kept the numbers small. Another way coul... |
- How does freezing food work? | [
"The process of decay is mostly microbial. So yes in cold temperatures it is functionally “paused” for a while (not forever though, just really slow)."
] | [
"\"magic\". This question is repeatedly asked. You need to ask more specific questions as there are a lot of things to answer."
] |
Why international means outside of your country. Shouldnt it mean within your country? | [
"Intra- is a prefix used to form words that mean on the inside, within. Contrast this with inter- and you immediately see the difference. While inter- deals with open systems among groups, intra- deals with closed systems between a single group."
] | [
"National radio stations' content has to be rebroadcast by local stations. Local stations sell advertising and just broadcast that during commercial breaks the national broadcast contains. It's similar to how you can watch Jeopardy (a national broadcast program) and still see an ad for a local restaurant."
] |
Why is it that you cant see stars in space on vids from ISS station for an example | [
"Stars are very dim, the only reason you can see them at night is a relative absence of other light sources. The Earth, on the other hand, is quite bright, and so are parts of the ISS exposed to direct sunlight. So, they generally have the exposure time and sensitivity on those photos and videos set so that objects... | [
"The ionosphere has a different composition at night then during the day due to the sun's rays not hitting it at night. Finland is very far North, and being the winter time the ionosphere is hit by very limited sun rays. The Ionosphere reflects certain radio waves, thus allowing you to hear stations from much farth... |
How do heatseeking missiles work? More specifically, how do they lock onto their target and track it? | [
"They have an infrared sensor that can detect heat. They also have some computing power and the ability steer themselves. So they scan for a source of heat that fits certain parameters and then make decisions to steer themselves into it. _URL_0_"
] | [
"If you lived a few thousand years ago, you could make a good map of the constellations of the zodiac piece-by-piece at night. Then, at sunrise or sunset, you could measure the angle between the sun and celestial objects that are visible even in daylight: the Moon, Venus, and Jupiter are the best choices. You then ... |
Why is eggnog, and other Christmas associated foods...Christmas only foods? | [
"Eggnog is a wintery drink as it warms you up. Candy canes were originally given to kids so they quiet down during the mass. Advent calendar came from the Christian time of [Advent](_URL_0_) to build up anticipation for Christmas. Ingredients used to make fruitcakes were once expensive and families could only af... | [
"You have to go back to where and how these sports were founded. American football and basketball were first popularized as collegiate sports, so they played during the school year. When professional leagues founded, the seasons generally followed the established times. In football, this was also because many early... |
ELIM5: How will facebook/google/amazon handle their collection of photos/videos/data 10/15 years down the road? | [
"Storage is getting cheaper just as fast as we're finding new ways to use it up. They'll just keep buying more, and more dense, hard drives. Many big companies (like Google) use a ton of off-the-shelf drives, so as those get cheaper and have greater capacity, these companies can take advantage by either replacing f... | [
"Bad website design. This is something that people making websites should know about, and that is relatively easy to make not happen. But many website designers choose not to care about it when they're making websites, so they don't stop it from happening. Often it's because they store \"what the website content is... |
Why gasoline smells so damn good? | [
"People like the smell? I can't stand it"
] | [
"We honestly don't know, but it is culturally universal. Clearly humans feel some connection to it that animals and other biological organisms do not in the same way. Perhaps some could claim it's a form of mate attraction, similar to birds singing or whatever, as it does tend to have that effect, as does many hu... |
Why is "Google Video" still so shitty? | [
"Because Youtube. There's no point in keeping two separate hosting services. For the same reason they abolished youtube login details, so now you log in with your normal Gmail username and password."
] | [
"It takes a while to implement the changes. How would you like it if the law changed overnight and you had to pay fees/go to jail next day without having a chance to adapt yet."
] |
If we were able to eliminate all microbes in specific setting, say a fridge, would food ever spoil? | [
"Removing all the organic activity (ie: bacteria) would not cause food to spoil in the classic sense, however even if you keep something biologically sterile, like canned food. It still goes \"bad\" over time. Chemical activity continues to occur, albeit slowly, which causes the taste to become, some cases, pretty ... | [
"Think of it like a hose... and a room made of sponge. The light bulb is a hose, spraying water (light) everywhere. The room is a sponge, absorbing the water (light) all the time. The moment you turn the light off, it's like closing the faucet to which the hose is attached. It stops spraying water (light) everywhe... |
Why are there F1-F12 keys on the QWERTY keyboard? What are the original uses of these keys, and why are there 12 of them? | [
"To access additional functions - before mice existed (or at least before they were common), it was an easyish way to get your program to do things. Software often came with a bit of card that you could stick on top of your keyboard so that you knew just what each F-key did. _URL_0_"
] | [
"Human twins aren't always identical twins. There's basically two different kinds of twins: Identical which happens when the fertilized egg splits into two, which then turns into two babies instead instead. Then there's Fraternal twins, which just means there were two lucky sperms instead of one, so there's two fer... |
Is there ever any variation between the individual Gs, As, Ts, and Cs of a single DNA strain? | [
"Sometimes cytosine is methylated (has an extra carbon attached), and the methylated genes are \"turned off\" and not expressed. This is one of the mechanisms of epigenetics. _URL_0_ There may be effects of deuteration of the bases (I don't know)...but this is unlikely to occur naturally."
] | [
"Think of cannabis like apples. There are red apples and green apples and even yellow apples. Each Apple tastes a little different, some are sweet some are more sour, but they are all still apples. Cannabis is the same way."
] |
Why arching your back feels more comfortable than having it straight, even though it's damaging? | [
"Sit with your back arched, and press on your stomach and back. You'll see they're quite relaxed. Now, sit with it straight. You'll feel your core is much more engaged (and therefore working hard) to keep you in that form. Essentially it's more comfortably (temporarily) because it is much easier on your body."
] | [
"In short, Neuroplasticity. Pain and pleasure are both literally \"just in your mind\". By that, I mean that what our minds interpret as pain or pleasure is dictated by the firing of certain neurons in our brains. The pain and pleasure areas lie fairly closely together in the brain. Neurons from one \"area\" can gr... |
What is a Cartel? How does it work? | [
"A cartel is an arrangement between companies or organizations that would otherwise compete with each other so that they can manipulate the market. Oil is the most famous example, but it's very political. Think of something a little more small-scale. Let's say you live in a hot place and everyone *needs* ice-cream.... | [
"I could try to explain it to you, but this video is all you really need: _URL_9_"
] |
How did David Bowie keep his cancer out of the media and so secretive? | [
"He didn't say anything about it, and neither did his family or anyone he told. Plain and simple."
] | [
"My guess? When you're dealing with a lot of makeup, prosthesis, special effects its easier to hide flaws. You can see acne under makeup in high def, you couldn't really see that back in the day. Just a guess."
] |
Why caller ID allowed spoofing when it was first created? | [
"It was for law enforcement. It is pretty easy to figure out which numbers are coming from a law enforcement agency, so caller ID would make it harder for them certain things, like undercover work. Law enforcement pressured telecoms to allow spoofing because think of the children, so it became a thing. Since there ... | [
"In many cases the recording company just wants to resell you the same album again. Depending on the fidelity and condition of the original recordings you sometimes can get better versions that what was originally available in the 70s, but you're not going to pull a crystal-clear version of an old Led Zepplin album... |
What actually makes gravity pull objects together? | [
"> is how somehow they just begin moving toward each other. We don't know, we just know they do. Ideas like gravitons have been floated, but no conclusive proof yet. > Furthermore, according to Einstein objects curve space depending on there mass, but what if objects are non planar to each other Well two things: ... | [
"We're not completely sure what the Great Attractor itself is, but we now know that it is not as massive as we first thought, and it is in fact a galaxy cluster *behind* it that the Milky Way is drawn to, and not the Not-So-Great Attractor itself."
] |
why do college football teams have a staggered punt formation but no one in the NFL does this? | [
"So in college you can send Gunners after the punt returner immediately after the snap, in fact ANY kicking team player may cross the line at the snap in college. While it is limited until after the kick in the NFL. So when you send your guys more and sooner you need that small shield of guys back to protect the pu... | [
"[Flechettes](_URL_1_), to use the technical term, were used extensively and somewhat successfully as an anti-infantry device, and also less successfully as an anti-zeppelin device. The idea was that just by dropping them en mass (boxes contained up to 250 darts, and [multiple boxes](_URL_0_) could be carried on a ... |
Why must businesses constantly grow? Why can't they just self-sustain? | [
"A lot of businesses DO just self sustain. We're talking small-medium businesses here, the ones that supply business to business. They supply the big companies you've heard of with everything they need they keep running. They make a tidy profit and the owner, rather than investing it back into the business, pockets... | [
"Inflation. Let's put it this way, in America it used to be that you could buy a steak dinner for let's say $5. Then today that same steak dinner would cost $50. How much we pay for things, and how much we get paid has increased slowly over time. In other countries, it has increased way faster, so something that us... |
Why has the US Govt been buying up ammunition en masse? | [
"The U.S. Government has always bought, and will always have to buy, ammunition. We can't have our brothers and sisters in the Armed Forces, Border Patrol Agents, US Marshals, FBI, DEA, Secret Service, etc. going around using nothing but knives and slingshots. Those agencies require the ammunition to train and take... | [
"Greetings everyone. In the few minutes this sub has been up, it's attracting sub-standard responses. Just a reminder of a few of the rules: * no responses covering events/conditions post-1994, per this sub's \"20-year rule\" prohibiting discussion of current events * no anecdotes * no speculation OP: your question... |
how did Guinness become the company to award world records? | [
"I think it is the same company that makes beer and from what I've heard, it was started to end arguments in the pub."
] | [
"My question on this that probably goes along with the OP is how is it these companies can claim \"ownership\" and why cant we at a consumer level, just claim our own domain name?"
] |
why and when clothes went from being used for warmth and protection, to it being socially unnaceptable not to wear them in public? | [
"Well for starters that's not the case in all human cultures. For those where it is, the answer almost certainly predates written history, but if i can speculate a little; when humans expanded into cooler regions , wearing clothes became the rule rather then the exception. Not wearing clothes, would carry increased... | [
"Hi OP, this is a cultural question, so it would greatly assist anyone considering answering if you could specify which culture you're asking about. For example, the name of a cultural group / country / geographic region, plus a rough time period. Otherwise, this question is simply too broad, as it encompasses almo... |
How was chemistry developed? | [
"One person you should do some research on is Dmitri Mendeleev. He is the one who invented the periodic table. (He is also well known for his research in vodka (yes he is Russian)). In a nutshell, he predicted the placement of the elements by their properties and weight. He was able to even predict undiscovered ele... | [
"Back then people still needed jobs, now they dont and can practice harder for longer. And science helps by showing then methods on improving motions. You cam find cool videos on youtube"
] |
What effect would the collapse of a dollarized country (such as Ecuador or Pananma) have on the USD? | [
"Not much. Any goods they provide to the US would be affected, but the value of the currency itself is based on things that are inside the USA. They just use the currency, they don't contribute much to it's value or backing."
] | [
"Hi, I've approved the post, but just a note to you and potential respondents: this subreddit has a 20-year rule against discussing current events, so any answers will have to cut off at 1997. If you're looking for answers that can include 1998-2012, do consider x-posting elsewhere, eg. a foreign affairs sub like /... |
Why does hot oil make a sizzling sound when something is put in it? | [
"It's not the oil, it's the water from whatever you put into it heating rapidly and boiling off."
] | [
"A stereo plug has three electrical contacts (tip, ring, and sleeve), assigned to left, right, and ground, respectively. The jack also has three contacts, aligned with those of a fully-inserted jack. When the plug is inserted into the jack, the contacts brush past each other, temporarily connecting improperly, then... |
How do I determine, as an American, if I have legitimate claim to the coat of arms and family crest used by my ancestors in the UK? | [
"The first step would be establishing a genealogical connection to the family. Have you actually traced your family tree? You have to establish a family connection (and often only in the legitimate male line) beyond just a name. Once you have done that (which can be long, tricky, but also rewarding in itself) and i... | [
"Go to a new area of Australia (or wherever). Comb one acre very carefully, cataloging every species. Figure out how many new species there are. Do this in a few different places, figure out about how many new species there are in general, and extrapolate."
] |
Why can't fake blood in movies look more real? | [
"It actually can, but it doesn't look as good. People have become used to seeing what they expect blood to look like in movies, and a more realistic version actually looks less real than than the real thing."
] | [
"It takes a great deal of human-hours as well as computer-hours as well as very expensive license fees for the software to make good quality CGI."
] |
Why are low sodium diets suggested for high blood pressure when low sodium levels result in higher renin production and therefore higher blood pressure? | [
"The latter. The purpose of the renin-angiotensin-aldosterone system is essentially to control blood pressure, blood volume, and sodium balance. Like you mentioned, reductions in sodium stimulates renin release. However, that is just one of multiple renin-release stimuli. The more correct way to see it is: (1) decr... | [
"Something I know about! Actually, mice are more common, but rodents in general are used for a few reasons. They're cheap, small, easy to handle, easy to house and feed (mmm autoclaved pelet food), can be placed with members of their own species, can't really hurt you, and reproduce quickly. Now, non human primat... |
How come teeth are so resilient that dental records are used to identify dead bodies and even severely burnt victims, but they are so fragile in living people that bacteria can rote them away? | [
"Dental records aren't used because teeth are resilient (although they are; at least more resilient than soft tissue and some bones), they're used because they're unique to each individual person. When fingerprints and DNA are long gone, a person's teeth can identify them. Bacteria don't rot teeth, at least, not di... | [
"Basically they introduce a very powerful taste so that the memory of the bite coming next isn't conflated with what you just ate. Otherwise it would be difficult to pick up the subtleties between, say, certain dishes of sushi. Fun fact, that ginger that comes with your sushi (called gari) serves this purpose. A lo... |
How do we have pictures of the Milky Way if the farthest satellite to travel from Earth just recently left our solar system? | [
"We don't have photos of the Milky Way from a distant point of view because we are in it and we can't leave it. But we can see the Milky way from our inside point of view, you can see it in the sky with your naked eyes (not as a spiral shaped galaxy like your image) as a broad ribbon brighter than the rest of the s... | [
"> I see pictures like this: _URL_0_ and long to see this sight for myself. I think those types of pictures are taken using decent cameras with high ISO settings and a long exposure time (maybe 25 seconds or more). They don't reflect what you'd see with the naked eye, unfortunately. Here's one photographer's rendit... |
what keeps the protons in the nucleus to not repel each other if same charges repel? | [
"This is the role neutrons play in the nucleus. The protons and neutrons are held together by strong nuclear force, which is stronger than electromagnetic force, but most nuclei would still fly apart if they were only composed of protons. The neutrons serve as 'glue' to add additional strong nuclear force, while se... | [
"When you suck on a straw, it isn't the suction pulling the milk shake up. It's the weight of the column of air above the milkshake, extending into space pushing down on top of the milk shake as air pressure. All you did by sucking was remove the weight of air on top of the milkshake straw that was holding it down.... |
How far away are asteroids from each other? | [
"It depends entirely on what kind of sizes you want to talk about, as there are far more light asteroids than heavy asteroids, but in general the answer is \"really really far away\". Note that the total mass of the asteroid belt is only 4% of the mass of the Moon ([1](_URL_1_)), while being spread out over an insa... | [
"The best images they will take will be able to resolve features ~100m across according to the mission website: _URL_1_ Here is an image of Callisto (moon of Jupiter) taken at 100m resolution: _URL_0_"
] |
Why do all the ELI5 posts start with ELI5 when that is the subreddit we are in? | [
"It's to differentiate between ELI5 posts and say, askscience posts on your front page. It also helps the answerer figure out how to word their post, as they will word it differently for an ELI12 or ELI18."
] | [
"You can change to \"simple English\" on the left side of the page, in the list of languages. And it will show you a more basic explanation of the topic written in language everyone should be able to understand."
] |
Why are websites containing illegal content or assisting illegal activities able to continue running? | [
"1. Unless the sites are knowingly or actively engaging in illegal business, and make a good show of effort to remove abusive/harmful material, they don't get punished. If that was true, you could upload an episode of Family Guy to YouTube and get them easily fined. 2. Not all criminal acts are equivalent. I think ... | [
"Imagine a bully at school. It's the same one each day, taking the lunch money of the same handful of kids. You take note that kids seem bullied, and it's very easy to identify who the bully is, after all you only have to talk to a handful of kids to get something of note, plus everyone is pointing the same direct... |
What are the benefits of kissing? | [
"One of the obvious effects is the emotional reaction and connection. Kissing, and touching in general, releases oxytocin, a hormone that can make one feel \"connected\". I do know that kissing does have cultural and relationship context that will alter its prevalence and effects. As to type of kiss, the effects wi... | [
"It doesn't. Scientific studies on neuro-linguistic programming have shown it to have no effect. _URL_0_"
] |
Why does it seem like the antivaccine argument outrage has blown up in the last week. What did I miss? | [
"You missed an outbreak of Measles, which hasn't really existed in the United States for about 30 years."
] | [
"There's not a more reputable source than the [CDC MMWR](_URL_0_), but a simpler way to keep track (and my personal favorite) is the [Jenny McCarthy Body Count](_URL_1_). The body count actually comes from CDC data. As for your question on vaccine risk to children, the first two minutes of [this Penn and Teller Bul... |
How come Australia's accent resembles the U.K. but the Canadian/ American Accent is so different? considering colonization from the Brits. | [
"For a long time while the Australia accent was forming, the island was inhabited almost exclusively by Brits (excluding the Aboriginals). It stayed this way until less than 100 years ago, when an influx of immegration from countries in Asia etc began. Canada/America on the other hand experienced much higher levels... | [
"So when the Congo was handed over from Leopold's personal control to the Belgian government what exactly changed in the colony? What improved, what didn't improve, etc? Also how did the Belgians justify the takeover of the colony to their people? It seems like having your government step in because your monarch i... |
Can anyone recommend a good documentary about the norse mythology? | [
"Not a documentary but a 3-part lecture series by [Professor Neil Price of Uppsala University](_URL_1_), given at Cornell University in 2012, entitled *The Viking Mind*: _URL_0_"
] | [
"I really liked Ron Chernow's \"Washington: A Life\". _URL_0_ ***** McCullough's Truman bio is awesome, BTW. I don't buy many books, preferring to read them for free from the library, but when I finished reading it, I went right out and bought a copy, just so I could have it on my shelf."
] |
How do cinemas use 'night vision technology' to detect if people are recording the movie? | [
"Most phones emit Infrared light to help it focus. (IR FOCUS) Or Lazer focus. Take your TV remote, point it at your phone camera, and press some buttons. You should see the light on the front of the remote light up on your screen, but you can't see it with the naked eye. The night vision aspect is where I get a li... | [
"That's not something that's been researched to the point of having an answer. For almost all deep sea organisms, we don't even know their general operating behavior patterns, let alone their sleep cycles. Since they exist in an environment that we cannot access, we can only observe them by doing one of two things:... |
when we first started measuring temperature how did we decide how large a degree would be? Was it merely and arbitrary figure that worked, or was there a specific reason behind it? | [
"It's based on water. They froze some water and decided that would be 0, they boiled some and decided that would be 100. So it's arbitrary in the sense that 100 is an arbitrary number but that's what it's based on. The temperature of boiling water will always be the same whether they decided to say it would be call... | [
"Congrats! You've asked what may be the single most-asked question on /r/AskHistorians. That's good news, because it means we have [a big FAQ file devoted to your question](_URL_1_). Check it out, and I hope it helps! *Edit: And [here](_URL_0_) is a great answer from /u/talondearg, who answers it quite a bit.*"
] |
Can a smart watch charge from everyday movement? | [
"For \"dumb\" watches we have had automatic movements which wind themselves with a free spinning pendulum inside the watch. The problem with converting that into smart watch tech is efficiency. There are a few companies trying to solve this right now. Sequent is one of them. Check out their kickstarter. _URL_0_"
] | [
"Yes it will, because you have changed your orientation. Here are two links that fill you in more on this matter. [This link](_URL_1_) explains what is going on. [This one](_URL_0_) has a number of images that show the effect."
] |
How less than $1 a day can "save a child's life". | [
"Cup of milk, cup of oatmeal, cup of water approx .75 cents total. Caloric and nutrient intake needed to stave off hunger"
] | [
"Have there been more than normal? I don't know if there's anything out of the ordinary. The media will often take any discovery in cell and molecular biology and apply it to the treatment of cancer, and researchers funding often comes from the treatment of disease. Sites share what sounds interesting, and I might ... |
How many comets burn up in Earth's atmosphere every year? | [
"The majority of visible meteors are caused by particles ranging in size from about that of a small pebble down to a grain of sand, and generally weigh less than 1-2 grams. From: _URL_0_ The average comet nucleus is less than 10 kilometers (6 miles) across. A small comet is about the size of a house. From googling ... | [
"Not directly answering your question, but several discovered extrasolar planets are termed [Hot Jupiters](_URL_0_) since they have similar mass and compositional characteristics to Jupiter, yet orbit *very* closely to their parent star. For instance, [51 Pegasi b](_URL_1_) orbits many times closer to its parent st... |
What all this talk of warp drives means? | [
"Just a warning, you're going to get a lot of opinions in here and they're going to be light on peer-reviewed evidence."
] | [
"_URL_0_ The wikipedia article is excellent and better than any of the answers in here so far. If you have specific parts you don't understand, ask away and I can help explain them to you."
] |
100 years ago today, WWI was well on it's way. It is certainly not an overnight thing, so on this day (perhaps a week or two forward and back), what are European countries doing in anticipation to the growing hostilities? | [
"I don't have the time to answer this in depth, but *1913: The Year Before the Great War* by *Charles Emerson* seems to be exactly what you're looking for. Be careful not to adopt a teleological view of history - even though it's obvious to us that WWI 'will happen', people at the time weren't quite so convinced. T... | [
"[This answer](_URL_0_) from /u/ETFox explains the limited involvement of the continent."
] |
Why does reducing the resolution of a video consequently affect the sound quality? | [
"No, that isn't the case at all. Sure, if you shrink a video by running it through some program on its default settings, without understanding what it's doing, then that might be what you get out. It doesn't have to be that way. If you learn how to use a command line processor such as [FFmpeg] (_URL_0_), you can ge... | [
"Think of your vocal cords as if they were rubber bands. Brand new rubber bands (like when you are young) are tight and bounce right back after being stretched. Now think of an older rubber band (like when you are old), having being stretched over and over. It doesn't have the same elasticity it once had."
] |
Do Godel's Incompleteness theorems currently have use whatsoever in Physics? If not, might they some day? | [
"Generally they do not. Theoretical physics isn't at the point where it can be axiomatized the way pure mathematics can be. There was a [paper last year](_URL_0_) about how a certain problem in quantum mechanics is undecidable, which you may find interesting. I should add though that some of the deeper mathematical... | [
"One consequence of the halting problem is that it is impossible to design an algorithm that can always answer right to : \"Will this instruction (or line of code) be executed during the program's execution ?\". This has application in my field (malware analysis). One of them is the impossibility of having a perfec... |
How do some fireworks makes shapes and whatnot when they explode? | [
"Imagine you draw a bunch of dots pretty close to each other on the surface of a deflated balloon. Then blow it up. The dots are much bigger and farther apart."
] | [
"Two methods: 1) Scale models in slow motion. Blow up a 1:64th scale white house with a can of gasoline and replay the film in slow motion. It looks very much like the actual building blowing up in real time. 2) Computers. Airplane crashes and large cityscape scenes are usually done with CGI backgrounds. The actors... |
When someone is close to falling asleep, why do certain noises (typically softer like a pen click or floor creak), briefly draw attention, momentarily "resetting" your drift off to sleep? | [
"When you're trying to go to sleep, you are letting yourself be extremely vulnerable to attack/dangers. So small noises like a predator animal walking/stalking you would wake you alot easier."
] | [
"Because bugs crawl on us, and some can be dangerous. Think about two phenotypes: A human with a shudder response to bugs, and a human without. In the wild, the human who shudders and reacts strongly to a bug on its skin gets the bug off of its skin as quickly as possible. If you've just walked through a spiderweb ... |
In music, why are time signatures in fractions that can be reduced not done so? Like, why is 6/8 time not 3/4 time? | [
"6/8 is **one** two three **four** five six (or, **one** and a **two** and a) 3/4 is **one** and **two** and **three** and"
] | [
"However much you use of the one part ingredient, you use three times that amount for the three parts one. Example, one part sugar, three parts flour is one cup sugar and three cups of flour. Or two and six, etc"
] |
If the Wacraft Movie cost 160M and its boxoffice is 430M, why is it still considered a loss? | [
"Wasn't the movie a loss in the US, but a success in China?"
] | [
"Often, it's really hard to tell a movie isn't working until you have written it, hired all the actors, shot the movie and get into the editing process. Movie making is so hard, even the greatest movies ever made can feel terrible during production. Look at star wars. You basically make 3 movies every time you mak... |
Why is there white stuff around your mouth in the morning? | [
"That white stuff is a mix of dead skin cells from your mouth, bacterial colonies, and digestive amino acids from your saliva, all dried up from evaporation."
] | [
"An object in motion tends to stay in motion while an object at rest tends to stay at rest. Simply put, when going to sleep your mind is still active since it has been active all day while when you wake up your mind and body have been comatose for an extended period of time which makes it harder to get moving again... |
Why is my reflection right-side up in the bottom of a spoon but upside-down in the top of a spoon? | [
"Basically, the inside of a spoon is a concave mirror and focuses the light inward such that the beams cross and the image appears inverted. A convex mirror (outside of spoon) reflects the beams outward. I draw picture: _URL_0_"
] | [
"Because the original explorers were Western Europeans, and we've just used modified revisions of their maps since everyone has been used to them. Defining North as the \"top\" of anything is a human attribution, and we could easily make the South the \"top\" of the world. [Here](_URL_1_) is a video from the tv sho... |
Is there evidence for former mountain ranges? | [
"Yes, the Petermann Ranges in Australia, was a mountain range considered to have possibly been higher than Everest, certainly comparable to it, about 550 million years ago at least. Now all that is left is a small ridge and Uluru and the Olgas, which is just dirt and rock runoff, from it eroding.. [Petermann rang... | [
"You can measure continental drift using VLBI, it's radio astronomy. You look at compact distant radio sources simultaneously with antennas on different continents. You can measure the distance between the antennas to a fraction of a wavelength using interfereometry. Over time, they noted a drift of the positions o... |
If a Thermos flask maintains heat by blocking conduction/convection by means of a vacuum gap in its walls, does that mean sound is also unable to travel through the walls? | [
"It _absolutely does_ mean that sound cannot pass __through__ the walls; but I stress \"through\" here, because if you put a soundsource inside & a detector outside, you will still get much sound arriving at the detector, as the sound will be transmitted quite effectively _along_ the walls & _around_ to the other s... | [
"Think of the cup and water as two different objects. You are providing forces for the cup(object 1) to move, buy you are not directly involved in the moving of the water(object 2). The water is moved by a coefficient of friction from the cup. As cups are usually quick smooth, the effect of friction is very low res... |
When you play a game like chess against a computer on "easy," does it simply look at less possible moves/scenarios or does it actually try to lose? | [
"The easiest way to make a computer chess program have an \"easy\" level, is, indeed, to decrease the number of positions they look at per move. However, some more sophisticated programs, actually insert moves they know are mistakes periodically. This second strategy makes for a more believable kind of game (that's... | [
"Imagine you are a travelling salesman, and you spend most of your time driving from place to place across the country. Today you need to get from Denver to Dallas. You could use High Level Navigation. You know how to get from Denver to Wichita, Wichita to Oklahoma City, and Oklahoma City to Dallas. String those to... |
Why are pictures of TSA Keys the only way to obtain copies of them? | [
"As /u/SVFeingold said it is easier to make a copy of a key from a picture than it is to copy the lock. The bigger issue here, from what I got in the link you attached, is that picture was of all of the master keys for the TSA. When you travel you are supposed to use a TSA approved lock on your baggage which the T... | [
"This is my field of research. My group in graduate school loaded ultra-short SWNTs (US-tubes) with [**Gadolinium ions** for MRI contrast enhancement](_URL_0_), with [**AtCl** for alpha therapy of cancer](_URL_3_), with [**molecular iodine** for CT enhancement](_URL_2_), and with [**cisplatin** for anti-cancer drug... |
How can we model the real world using mathematics if things like the Banach-Tarski Paradox are allowed? | [
"There's no reason to expect every aspect of math to apply to be applicable to every situation in physics. Just use the right math for the right situation, and move on. You can think of scientific theories as a guide that tells you which math to apply in a particular scenario. Though it's considered ugly, it is po... | [
"This has actually already been done, [here is a video](_URL_0_). The problem is that the image coming from the eye is full of gaps and errors which our brain has evolved to cover up. We think we see a perfectly clear image but in reality it's distorted and constantly waving back and forth."
] |
In the ancient Spartan society, is there evidence of the kings training in the agoge with other boys their age, or did they have separate training? | [
"From what I remember, we believe that the kings were exempt from the training. This seems surprising because one of the kings was expected to lead and fight in military expeditions. If one of the kings failed the training as so many Spartans did, it would lead to ridicule. The Spartans ridiculed those who failed i... | [
"Yes, you can do sparse pairwise comparisons and still get decent ratings. This has been done for decades in chess, for example, with the Elo system. Glicko and Glicko-2 are highly regarded generalizations of Elo. Most online games today involve some sort of server-side rating system, although these tend to be more... |
Is there no beginning of time with science? | [
"The present understanding is a bit muddled. The main camp I'd say believes that time itself is created at the big bang, and that's the beginning of time. The other large camp believes that time exists in a way through the big bang to some \"thing\" earlier, but the big bang is a wall that is impenetrable to measur... | [
"Computers have quartz crystals that vibrate a known number of times per second when they are wired up. We tell the computer to count the oscillations and make time measurements based on the counting."
] |
Why is Japanese porn censored? | [
"A law forbid to show penis and vulva (actually,forbid to show *obscene* materials and sexes have been considered obscene); hence censorship on porn."
] | [
"What do you mean here, can you provide specific examples? Most of South America is still extremely catholic and conservative, including when it comes to sex and sexuality."
] |
What is happening when I'm so sleepy that my eyelids feel heavy? | [
"Your eyelids are raised by a muscle that is partially controlled by the part of your nervous system (the \"sympathetic\" nervous system) that is responsible for activating and energising your body (you may have heard of it in relation to the \"fight or flight\" response). When you get very tired that part of your ... | [
"The lens in your eye takes light that is coming in from all directions and focuses it into one spot on the back of your eye. The reason your eyesight is poor is because the lens isn't focusing the light correctly. When you squint, you're limiting the angles that light can come into your eye. With only a tiny slit ... |
How did wrestling become staged? | [
"How was the general public generally OK with the gradual revelation that this spectacle presented as a sporting event was completely staged, as compared to other sports-fixing scandals or the game show fixing scandal of the 50s? Especially considering that until fairly recently, pro wrestling had to do its busine... | [
"My guess? When you're dealing with a lot of makeup, prosthesis, special effects its easier to hide flaws. You can see acne under makeup in high def, you couldn't really see that back in the day. Just a guess."
] |
Biology: Why is it that many frogs that are poisonous are also vividly colorful? If their poison is to discourage predators from eating them, why didn't they evolve to be visually less attractive? | [
"Those bright colors are actually there to discourage their predators from eating them. It's like saying \"fuck with me and you're gonna get poisoned\". This is also why some animals that aren't poisonous have evolved to mimic bright colors, fooling predators to think they should stay away from them."
] | [
"> Why is the \"Sexy Son Hypothesis\" presented by Prof. Richard Dawkins scientifically substantiated? This sort of sounds like a loaded question as it assumes the hypothesis is \"scientifically substantiated\", whatever that means. The general idea is that the most important aspect by which a female would choose h... |
Does the sun really produce enough energy in one minute to power the planet for an entire year? | [
"See here: _URL_0_ 5.0x10^20 J is the total world energy consumption in 2010 1.5×10^22 J is the total energy from the Sun that *strikes the face of the Earth* each day. So 300 times more energy reaches the earth each *day* than we use in a year. The *total* energy output of the sun each day is of course many order... | [
"Car engines are extremely heavy. The starter motor for an ordinary car may briefly put out more than 4 horsepower. (Notice the huge battery it uses.) It's not realistic do do that with a kickstarter. What you *can* do is get a human-powered charger and use that to refill a battery that will provide that surge of p... |
Why do so many languages around the world have similar words for "mum" (and "dad" to a lesser extent)? | [
"They are based on phonemes, basic sound parts of language. These are some of the first sounds a baby can mimic. Calling to one's parents is vital at early ages."
] | [
"Read up on [Paul Ekman](_URL_1_) and his development of the [Facial Action Coding System](_URL_0_). A good introduction/explanation of his research is found in the book [Blink](_URL_2_) by Malcolm Gladwell. The short answer to your question is, 'no'. From the wikipedia article on Paul Ekman linked to above: > Ek... |
How do astronomers account for the mass from dark matter when calculating the mass of a star/planet? | [
"The mass of dark matter on such a small scale is negligible. The density of dark matter in our part of the galaxy is 10^-2 solar masses per cubic parsec (10^-12 kg per cubic km), so all of the dark matter in the entire volume of the solar system within the orbit of Neptune only has the mass of a small asteroid. On... | [
"The current recommended training regime of astronauts on ISS will keep most of their muscle mass and bone density or even increase them in places. There is still some refinements needed to make it perfect as there is some issues with bone density in the pelvic region as the astronauts do not balance enough when th... |
Why does Sound move slower than light if they both have 0 mass? | [
"Light is (in a basic sense) a massless particle. This allows it to move at C, the famous \"speed limit\" of the universe. While sound is technically massless, it is misleading to say so. It is a compression wave. Waves do not themselves move because they are not made of matter. Instead, they are defined by the mov... | [
"The Planck length is not an exact measure. It is just an estimation of the *order of magnitude* of the length scale in which quantum gravity effects are expected to be important. Its value even changes depending of the normalization (using 4πG=1 instead of G=1 leads to a different value of the Planck units). Physi... |
Can anybody help identify the following Second World War bomber? | [
"The plane in the air could be a B-26 Marauder, which is a twin engine bomber. The curve of the trailing edge in the still/movie appears to match that of the Marauder. I say could because the nacelle of the engine for the Marauder extends past the trailing edge. In the still/movie, the nacelle appears not to do tha... | [
"There was a quite good documentary ([Kanalinseln im Krieg](_URL_4_)) on german television a few weeks ago (I just found, it's at least a year old), and I don't know if those ever get translated into english. But it might be a starting point, and maybe you can find a subbed version on the net the [BBC](_URL_5_) has... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.