Split (2)

train · 226k rows

question stringlengths 3 301	answer stringlengths 9 26.1k	context list
Contemporary criticism of the Maginot line?	Follow up, how impenetrable was it, really? What sort of attack was it designed to repel?	[ "The psychological factor of the Maginot Line has also been discussed. Its construction created a false sense of security, which was widely believed by the French population. Kaufmann and Kaufmann comment that this was an unintended consequence of André Maginot's efforts to \"focus the public's attention on the wor...
why do sharks expose their top fins above the surface?	Sharks -- most species, anyway -- are true predators. Many of those predators hunt air-breathing species... seals, sea-lions, turtles, etc. The shark would prefer to be far below the surface, as it is a true fish. However, the air-breathers that they prey upon, quite naturally spend a lot of their time at or near th...	[ "Fin skeletons are elongated and supported with soft and unsegmented rays named ceratotrichia, filaments of elastic protein resembling the horny keratin in hair and feathers. Most sharks have eight fins. Sharks can only drift away from objects directly in front of them because their fins do not allow them to move i...
what are the benefits and drawbacks of having an overvalued or undervalued currency?	Overvalued- It's easier to buy imported stuff cos they're cheaper than your domestic stuff. Even though your currency is worth more, theirs is worth the same, so their prices will decrease from your perspective. On the downside, your domestic market suffers, and so do your country's exports, because they are costly rel...	[ "The currency exchange rate exerts a significant influence on the trade balance, and by extension, on the current account. An overvalued currency makes imports cheaper and exports less competitive, thereby widening the current account deficit (or narrowing the surplus). An undervalued currency, on the other hand, b...
Was it correct to call the decline of Aboriginals in Australia, a 'genocide'?	u/ispeaknoamericano wrote a great answer, and I'm especially happy that they addressed non-violent forms of genocide as well - a community can't survive if you take away most of its children and ban what makes it different. We focus far too much on the invasion, and far too little on the persecution that continued unti...	[ "It was originally claimed that Australia was uninhabited. The Stolen Generations are the mixed (Australian Aboriginal and white Australian) children who were forcibly removed from their homes and families. According to the Stolen Generations webpage, \"The notion that the absorption or assimilation of some Aborigi...
What does the Holy Roman Empire have to do with Ancient Rome, if anything?	"The Holy Roman Empire," quipped Voltaire, was "neither Holy, nor Roman, nor an Empire"! The name was more an invention to legitimate the emperors as emperors, like the old caesars were in the Roman Empire.	[ "The Holy Roman Empire was founded centuries after the fall of Rome but brandished the name of the Roman people and honoured the king with the title \"King of the Romans\". Despite this, the Holy Roman Empire was largely a Germanic affair with German kings, although its territory was considerably greater than prese...
How can we know the energy of the universe* is constant? (also Quantum Physics)	Okay so we have this really famous theorem from Emmy Noether: For any symmetry of physics, there must be an associated conserved quantity. So we have some neat mathematical ways of expressing physics, two of which are the "Lagrangian" or the "Hamiltonian." And suppose I take those mathematical expressions and add some...	[ "Zero-point energy (ZPE) is the lowest possible energy that a quantum mechanical system may have. Unlike in classical mechanics, quantum systems constantly fluctuate in their lowest energy state due to the Heisenberg uncertainty principle. As well as atoms and molecules, the empty space of the vacuum has these prop...
why do european countries have to accept refugees from the middle east and elsewhere?	Because they have signed (at the very least) the [UN treaty related to status of refugees] (_URL_0_) ([full text] (_URL_1_)). That is, the 1951 convention and the 1967 protocol. All members of the European Union have signed] both.	[ "Refugees coming specifically from the Middle East have been attempting to seek asylum in Europe rather than in countries surrounding their own neighboring regions. In 2015, over 80 percent of the refugees who arrived in Europe by sea, came from Syria, Iraq, and Afghanistan. Routes in which these refugees face whil...
why do mushrooms taste like meat?	They don't. Mushrooms have a very earthy flavor, which is something that some meats also share, but they in no way actually taste like meat on their own. If you do not often eat meat on pizza that similarity may be what you are picking up on and you assume it is meaty flavor.	[ "The mushroom is edible and has a sweet taste. While the species is edible, old mushrooms may be spongy and soft inside. The species is high in nutrition and can be used for cooking. The authors of \"North American mushrooms: a field guide to edible and inedible fungi\" said that the mushroom has a pleasant odor. \...
blood types. what are all the different types, what's the rarest, who can donate to who, and why can only some donate to others and others can't.	OK - I'll give it a go - it's been a few years since I looked at this - you all lemme know how I did.... The types are: A, B, O and AB. There's also an Rh Positive and Rh negative. We'll skip the Rh stuff till later. You can think of the A and B types as being kinds of "spikes" or "sticks" on the surface of a red blo...	[ "In addition to the ABO and Rh blood group systems, there are more than two hundred minor blood groups that can complicate blood transfusions. These are known as rare blood types. Whereas common blood types are expressed in a letter or two, which may be a plus or a minus, a smaller number of people express their bl...
Why wouldn't the armies of the 1700s and 1800s use something like armor to stop gunshots?	There's always more to be said; while we wait for that, u/WARitter has dealt with this subject previously. [This thread asks](_URL_2_) basically the same question from another direction, and [in this answer](_URL_1_) he expounds further on the difficulties armour had to face to be effective in a world of increasingly e...	[ "In the decades leading up to the Civil War, numerous advances had been made in small arms technology. The flintlock, which had been in use for over two hundred years, had been replaced by the caplock in the 1840s. Muzzle-loading rifles had been in use for many years but prior to the Civil War had been very rare in...
why does the periodic table allow us to predict the properties of other atoms	It first started off the other way. That is, scientists noticed that the then-known elements could be arranged in a grid that grouped common behaviors together. The table had gaps then, which were predicted to be undiscovered elements. This later turned out to be true as new elements were discovered. TLDR, ELI5: The ...	[ "The form of the periodic table is closely related to the electron configuration of the atoms of the elements. For example, all the elements of group 2 have an electron configuration of [E] \"n\"s (where [E] is an inert gas configuration), and have notable similarities in their chemical properties. In general, the ...
why are foreign language classes and language immersion programs not taught from the most basic perspective (like elementary school)?	Because the students know how to read and write in their own language. In many languages the letter are identical. If you know one alphabet system learning to read another is easier then learning to read the first one. When you learn to write your own language you are learning to write a language you already can spea...	[ "Dual Immersion classrooms encourage students but with the permission it may be enthusiastic &' native language development, making an important contribution to heritage language maintenance and allows language minority students to remain in classrooms with their native English-speaking peers, resulting in linguist...
Is there a magnetic field created by the quarks in a neutral particle, like the neutron? And if not, why?	The neutron does have a magnetic dipole moment, as explained [here](_URL_0_) in some detail. The magnetic properties of the neutron are often exploited in neutron scattering to study the structure & dynamics of various materials, perhaps most clearly in the [neutron spin echo method](_URL_1_).	[ "It was later discovered that protons and neutrons were not fundamental particles, but were made up of constituent particles called quarks. The strong attraction between nucleons was the side-effect of a more fundamental force that bound the quarks together into protons and neutrons. The theory of quantum chromodyn...
Could you actually fall into a black hole ?	If you jump into a black hole, you will pass the event horizon and reach the singularity within a finite amount of time. For most stellar sized black holes, this takes a small fraction of a second from your point of view though as you're shredded by tidal forces so you won't be alive for it. For super-massive black hol...	[ "Observers falling into a Schwarzschild black hole (\"i.e.\", non-rotating and not charged) cannot avoid being carried into the singularity, once they cross the event horizon. They can prolong the experience by accelerating away to slow their descent, but only up to a limit. When they reach the singularity, they ar...
how do all planets become to be near perfect spheres?	As Carl Sagan once explained in Cosmos: (paraphrasing) Take a ball of clay (not spherical, just a rough shape) of clay, then put your hand on top and push down, then turn it over and do it to that side, then keep turning it over in different angles and pushing down on top. Eventually, you will end up with a spherical ...	[ "In the fully developed Aristotelian system, the spherical Earth is at the center of the universe, and all other heavenly bodies are attached to 47–55 transparent, rotating spheres surrounding the Earth, all concentric with it. (The number is so high because several spheres are needed for each planet.) These sphere...
why don't gas giants solidify?	At the temperature they're at, they're gasses. There's not a lot of ways to loose heat, besides radiating in space. If you're orbiting a sun there's an influx of heat. These usually balance each other. So temperature should remain constant.	[ "Gas giants consist mostly of hydrogen and helium. The Solar System's gas giants, Jupiter and Saturn, have heavier elements making up between 3 and 13 percent of their mass. Gas giants are thought to consist of an outer layer of molecular hydrogen, surrounding a layer of liquid metallic hydrogen, with a probable mo...
Are invasive species (such as lion fish in the Gulf of Mexico) just natural selection, accelerated by humans introducing species into new environments?	That's doubtful. Lion Fish are a small and very slow moving fish that survive in warm waters down to 300 ft. It's very unlikely that one could survive a trip across the Atlantic Ocean from the Indian Ocean through the Suez canal (their closest natural habitat to the east coast of the US) There's nothing for them to ea...	[ "Two of the twelve species of \"Pterois\", the red lionfish (\"P. volitans\") and the common lionfish (\"P. miles\"), have established themselves as significant invasive species off the East Coast of the United States and in the Caribbean. About 93% of the invasive population in the Western Atlantic is \"P. volitan...
why are we investing billions in fighter jets? shouldn't they be replaced by drones?	> near future do exactly what fighter jets do now? magical word: near future. they can't do that now. and probably for quite some time they will not be as good as humans. and second thing, drones can be jammed, with planes it's much, much harder.	[ "Drones are unoccupied aircraft vehicles that are remotely controlled by a person. While often associated with military use, the decreasing cost of the technology has allowed for civil use of drones to grow. Drones are being increasingly used in the fields of resource management and conservation because of their li...
before modern day lawn mowers existed, how were golf courses like st. andrews able to cut & maintain that much land dating back to the late 1700's?	Modern mowers were invented in the 1830s. Before that, they'd either have peasants go out there and scythe the grass down, or they'd have flocks of sheep graze it down.	[ "After World War II gravel was extracted from the site and subsequently used for landfill until the late 1960s. The golf course was established in 1977. The course was designed by Fraser Middleton and opened in 1979. Operation of the course was leased to \"Parpost Ltd\" in 2005 and \"John Laing Integrated Services\...
why does rigor mortis make bodies stiff?	It has to do with the way your muscles work. The muscles have fibers that extend and contract using the energy of ATP molecules. Those fibers are mainly made up of actin and myosin. They slide along each other to make the movement. But the way it actually works is that ATP breaks the connections between those fibers to...	[ "Rigor mortis (Latin: \"rigor\" \"stiffness\", \"mortis\" \"of death\"), or postmortem rigidity, is the third stage of death. It is one of the recognizable signs of death, characterized by stiffening of the limbs of the corpse caused by chemical changes in the muscles postmortem. In humans, rigor mortis can occur a...
Scholars of Reddit, I'm a junior in college taking BS Biology. I want to get into stem cell research but I need to know how to get into the right track.	Going to graduate school is pretty much a prerequisite to having a career in biology/medical research. But there are a lot of other things you can do now or before then: Are you at a research university? If so, there probably will be a lab researching stem cells of some kind. You should definitely look into it, and if...	[ "The Science Research Department is a four-year elective program situated in the school's Biotechnology Laboratory. It allows students with a declared interest in science to conduct original research alongside of researchers at college, university, hospital, and medical school laboratories. The courses include Intr...
why would an asteroid collision wipe out life on earth?	> but would it stay there for so long that we would all freeze to death? Your bigger worry is starving because all the plants have died out due to lack of sunlight. But yes it would stay up there for months AT LEAST. Assuming you weren't caught in the blast or any of the earthquakes or megatsunamis such an impact wo...	[ "Asteroids that impact the Earth have led to several major extinction events, including one which created the Chicxulub crater 64.9 million years ago and which is associated with the demise of the dinosaurs. Scientists estimate that the likelihood of death for a living human from a global impact event is comparable...
how come when one really needs to go pee, they're completely okay when in any other room, but as soon as they reach the bathroom to relieve themselves, they almost pee their pants?	Classical Conditioning. If you ring a bell and then give a dog treat, and continously repeat this process until its engrained in the dog’s brain, then the next time you ring the bell, the dog will automatically salivate. Same with us and bathrooms. We see a bathroom, and then our brains automatically prepare for us to ...	[ "Generally, patients who are able to are encouraged to walk to the toilet or use a bedside commode as opposed to a urinal. The prolonged use of a urinal has been shown to lead to constipation or trouble urinating.\n", "Functional incontinence is a form of urinary incontinence in which a person is usually aware of...
What happened to the alleged cold fusion that Italian Andrea Rossi was working on?	Rossi was, I believe, convicted of fraud. [Take this claim with an entire mine of salt.](_URL_0_) [edit] the conviction was later reversed. It's still almost certainly a scam.	[ "In 1989 following the apparent discovery of cold fusion by Department of Chemistry chair Stanley Pons and British colleague Martin Fleischmann, the University of Utah immediately began plans to construct the National Cold Fusion Institute in Research Park and appointed College of Science dean Hugo Rossi as directo...
What would a day in the life of Marie Antoinette look like?	Marie Antoinette's days began with her own semi-public rising ceremony that paralleled the king's lever. Upon waking up around eight, she would be handed a dressing gown, and then take breakfast (little but coffee or hot chocolate) either in bed or at a small table nearby. Some mornings, a tub would be rolled into t...	[ "Marie Antoinette: The Journey is a sympathetic 2001 biography of archduchess Marie Antoinette, the Queen of France (1774–1792) by Antonia Fraser. It is the basis for the 2006 Sofia Coppola film \"Marie Antoinette\".\n", "In her historical biography, \"Marie Antoinette : The Journey\" Antonia Fraser claims Marie ...
what causes abnormally high jackpots? is is just chance and replication? or are there other mechanisms involved?	As the jackpot rises and it becomes more publicized, more people play, which adds more money to the jackpot. If this continues through several cycles with no winner, they can grow rather dramatically, as we've seen recently with the $400 Million bump.	[ "Probability of the jackpot changed depending on the jog selector. When the jackpot was obtained, from the beginning, players could listen to \"Crazy 4 U,\" \"Cutie Honey\" or \"Ningyo-Hime.\" A second consecutive win opened \"Wind,\" a third opened \"Butterfly\" and a fourth opened \"Selfish.\" On the sixth consec...
why is breakfast the only meal where it's socially acceptable to only eat a dessert? (doughnuts, pancakes, cinnamon rolls, muffins, etc.)	Those aren't breakfast foods, those are foods that accompany coffee/tea. As our lifestyle has evolved to where we no longer eat a full breakfast, but rather we caffeinate and maybe eat something to go with it, pastries have evolved into de facto "breakfast" foods.	[ "Tapioca flatbreads or pancakes are also commonly served for breakfast in some states, with a filling of either coconut, cheese or condensed milk, butter, and certain meats. They can also be filled with dessert toppings as well.\n", "Bread (' or ') is traditionally sourdough baked from rye and wheat, and is flavo...
why is the "k" silent? as seen in: knack or knock	In the 1600s, the K was pronounced. Pilgrims in America said "kuh-nife" and "kuh-nee" for knife and knee. It died out around then, but spelling had become set, So we kept that.	[ "The letter ⟨k⟩ is normally silent (i.e. it does not reflect any sound) when it precedes an ⟨n⟩ at the beginning of a word, as in “knife”, and sometimes by extension in other positions, such as “tight knit”. Exceptions include the town of Knoebels Grove ( ) located in Pennsylvania in the United States, the Germanic...
Is it hard to be a history professor or a historians?	This is a question that gets asked with a fair amount of frequency, both here and at /r/askacademia. [this is a recent thread](_URL_2_) where /u/restricteddata and /u/dire88 explore some of the aspects of the academic job market for history. [this thread](_URL_1_) also discusses grad school, academic employment, and...	[ "The Harvard University Department of History is home to some of the world's leading and most renowned scholars in history. The department focuses on multiple areas within history \"including social life, the economy, culture, thought, and politics. Students of history study individuals, groups, communities, and na...
How does this work?	By definition, melted rock beneath the surface is called magma. Once it erupts, it is called lava. The distinction is largely semantic and done for convenience (i.e. by describing it correctly as either magma or lava, you are conveying extra information in terms of its location), though there are some true differences....	[ "It works by injecting the material stream to be sorted into a chamber which contains a column of rising air. Inside the separation chamber, air drag on the objects supplies an upward force which counteracts the force of gravity and lifts the material to be sorted up into the air. Due to the dependence of air drag ...
This might be startlingly ignorant, but: why are sunny days in the winter still cold?	The reason that the tilt makes it more cold in winter is not distance. Yes, the sun is less bright the further out you travel from it, due to the spreading of the light. The reason that the winter is colder is because when you have the surface at an angle to the incident light, you're taking a lot less of the angle of ...	[ "Temperatures are hot in summer reaching up to , and in winter are cool, either because of the fog (about twenty days from November to January ) or a cold and dry wind blowing from the northwest, the \"Cierzo\" (related to other northerly winds such as the \"Mistral\" in the SE of France) on clear days. Frost is co...
A question about US colonization	You might want to check out David Hackett Fischer's Albions Seed which addresses how the different British Isles groups who settled in British North America determined how the different American regions developed. It is an easily readable book even for those with only a casual interest in history.	[ "The history of colonization is complex, varied according to the time and place. France and Britain were the main colonial powers involved, though the United States also began to extend its territory at the expense of indigenous people as well.\n", "In order to understand what constitutes successful colonization,...
When did tourism become a large part of countries incomes?	That depends a lot on the country. And where there. For example - Austria (where i live) had areas with a vibrant touristic economy starting in the 19th century. Especially areas like semmering (the closest mountains to Vienna) became available for day trips with the construction of the train line there. Same is true...	[ "The 19th century also saw the rise of tourism as an important industry (linked with the improvement in passenger ships) which reached its climax in the period from the end of the Second World War to the 1980s.\n", "The tourism industry first truly flourished during the late 19th to early 20th century due to the ...
Would it be possible to make a radio which uses a different type of electromagnetic radiation?	You can certainly transmit data using visible light - that's what an optical fibre does, after all. However, radio has the advantage that it generally passes through most objects (e.g. walls), and so you don't need line-of-sight to the transmitter. With visible light, you would need to be able to see the sender, which ...	[ "To prevent interference between different users, the artificial generation and use of radio waves is strictly regulated by law, coordinated by an international body called the International Telecommunications Union (ITU), which defines radio waves as \"electromagnetic waves of frequencies arbitrarily lower than 3 ...
In regards to "nitrogen narcosis", how does the gas we inhale while diving suddenly become narcotic to us at great depths?	You need to understand a little about how SCUBA works. You can snorkel at the surface, right? What if you had a 12 foot snorkel, would it work? No, but why? Because the weight of 12 feet of water is squeezing you body. You don't feel it because hey we are made out of water. However, it's more weight than your lung mus...	[ "Nitrogen narcosis is also called “L’ivresse des grandes profondeurs” or \"rapture of the deep\". Nitrogen comprises 79% of the air, but at surface pressures it has no sedating effect. At greater depths, however, nitrogen affects the brain in the same way as nitrous oxide (also known as laughing gas) and other anae...
if the speed limit isn't actually a hard upper bound, why don't we just post a target speed instead?	I've been pulled over for 26 in a 25. It's up to the cops discretion, and some cops are dicks. The speed limit is a hard upper boundary, but it is up to the individual officer whether to enforce that strictly or not.	[ "BULLET::::1. When speed limits are arbitrary, such as when set through political rather than empirical processes, the speed limit's relationship to the maximum safe speed is weakened or intentionally eliminated. Therefore, a crash can be counted as speed-related even if it occurs at a safe speed, simply because th...
What were the role and effectiveness of archers and crossbowmen during the hundred year war?	That blog post was written by someone who views themselves as very educated on a topic they don't seem to have read much about. He starts off relatively alright- myth of longbow archers as super soldiers, pointing out the relatively similar composition of French and English armies- then becomes so determined to tear do...	[ "The traditional role of archery on the medieval battlefield was to begin the action, advancing in front of the main body of the army, as occurred at the Battle of Hastings. This continued to be a standard tactic, particularly in the absence of enemy cavalry. The Swiss crossbowmen and handgunners of the 15th centur...
what would happen if a queen was carrying a king's son, but the king died.	It would depend on the time and country. Different countries all had different rules of royal succession, and those rules changed over the course of history. There is no actual single answer to this question. It would be like asking, "What color is everything?"	[ "A king's queen died when his son was born. He remarried, and his new wife also had a son. The stepmother tried to poison the first son so her son would inherit, but her son warned his brother. The first son decided to flee before she succeed, and his brother went with him. They tried the drinks she had given the o...
why do contestants on "jeopardy" pick the lowest amount of money questions first?	Daily doubles are often hidden in the larger amounts, they are not useful when you only have $500 to bet on. Also some categories want answers that aren't quite straight forward (like "before and after"), so contestants want to get the hang of it before forfeiting larger amount questions.	[ "The next question was worth $5,000, and a contestant had to answer correctly to advance. If correct, the contestant would have a maximum of eight questions to answer, being forced to bet at least half of what they had at that particular point in the game. The catch was that each question came from one of ten diffe...
How many vehicles are there on Earth right now that are capable of spaceflight?	If you don't care about them being human rated, the answer is probably a lot. Russia (and people that contract them for launches) frequently use old ICBMs (e.g. _URL_0_) to launch satellites.	[ "The Lunar Roving Vehicle could be folded into a space 5 ft by 20 in (1.5 m by 0.5 m). Unloaded, it weighed 460 lb (209 kg) and when carrying two astronauts and their equipment, 1500 lb (700 kg). Each wheel was independently driven by a ¼ horsepower (200 W) electric motor. Although it could be driven by either astr...
Can UV light kill fleas?	UV light can kill pretty much anything, if you leave it under the UV long enough. It's used pretty commonly as a disinfectant in labs and hospitals already, though sterilisation cycles are generally minutes to hours long depending on what you're trying to kill (bacteria, fungus virus, bacterial spores). This thing in...	[ "Ultraviolet traps called bug zappers are used to eliminate various small flying insects. They are attracted to the UV and are killed using an electric shock, or trapped once they come into contact with the device. Different designs of ultraviolet radiation traps are also used by entomologists for collecting noctur...
A finding of life based on what at first appeared to be metabolic activity?	Here's a good article from Wikipedia: _URL_0_ The experiment that caused all the controversy was the "Labeled Release" one. This incubated Martian soil with a dilute solution of nutrients, each of which had carbon-14 incorporated into it. The headspace gases were analyzed to see if any of the 14C had ended up being c...	[ "It was the discovery of enzymes at the beginning of the 20th century by Eduard Buchner that separated the study of the chemical reactions of metabolism from the biological study of cells, and marked the beginnings of biochemistry. The mass of biochemical knowledge grew rapidly throughout the early 20th century. On...
Are there any sources for the trial and execution of Socrates that were not written by his students?	No, but there is one other primary source on Socrates which focuses on his early life: the playwright Aristophanes. It is generally accepted that the three mostly intact sources for the life of Socrates are found by the following authors: Xenophon, Plato, and Aristophanes, the latter of whom was less than flattering b...	[ "The extant, primary sources about the history of the trial and execution of Socrates are: the \"Apology of Socrates to the Jury\", by Xenophon of Athens, a historian; and the tetralogy of Socratic dialogues — \"Euthyphro\", the \"Socratic Apology\", \"Crito\", and \"Phaedo\", by Plato, a philosopher who had been a...
How effective was the boomerang as a weapon?	400-500g is a not unusual weight for a boomerang (straight-flying hunting boomerang, rather than a returning boomerang). An experienced thrower can throw such a boomerang at speeds in excess of 20m/s, for kinetic energy of over 100J (translational kinetic energy, not counting the rotational kinetic energy). This is ap...	[ "Boomerang's most dangerous asset is, naturally, his arsenal of specialized boomerangs designed by Justin Hammer. He has modified and improved on them over the years, but the most common ones are exploding \"shatterangs\" (with enough explosive power to destroy an automobile), \"gasarangs\" that release large doses...
i know why animals/humans store fat, but how and why do plants that grow fatty fruits collect and store fat (avocado, coconut, olives, etc)?	I believe sometimes a fruits/seeds will contain nutrients for making new plants/trees. The growing plant will find it easier to find sustenance I also believe that sometimes it is to trick animals into eating the seeds and pooping them out far from the original tree. But I am not a scientist	[ "Although fruits provide a source of carbohydrates, they have very little protein, and because protein cannot be stored in the body as fat and carbohydrates can, fruitarians need to be careful that they consume enough protein each day. When the body does not take in enough protein, it misses out on amino acids, whi...
if we were able to remove the brains ability to release dopamine and serotonin, would we be able to feel happiness?	Nope, because we'd be dead. While those neurotransmitters do affect mood, they also have other very important functions. For instance, Parkinson's Disease is caused by a loss of dopamine. And serotonin deficiencies often cause babies to just suddenly die.	[ "Chronic secretion of stress hormones, glucocorticoids (GCs) and catecholamines (CAs), as a result of disease, may reduce the effect of neurotransmitters, including serotonin, norepinephrine and dopamine, or other receptors in the brain, thereby leading to the dysregulation of neurohormones. Under stimulation, nore...
why are some features of humans, like hands and skulls, so innately hard to draw?	Aside from their intrinsically complex shapes etc that others already mentioned, we are also more adept at detecting aberrations from the norm regarding human anatomy. If someone draws a weirdly warped car or chair for example it might not look as strange as a bizarrely drawn face or appendage, because our brains are f...	[ "The abilities which involve the use of hands develop over time, starting with primitive gestures such as grabbing at objects to more precise activities that involve precise eye–hand coordination. Fine motor skills are skills that involve a refined use of the small muscles controlling the hand, fingers, and thumb. ...
why are logos and layouts getting simpler?	It's just the current popular style. Flat simple forms are the current "in " look, so that's what companies are adopting to seem more relevant. In 5-10 years, odds are good some other basic design trait will be the new fad.	[ "In today's digital interface adaptive world, a logo will be formatted and re-formatted from large monitors to small handheld devices. With the constant size change and re-formatting, logo designers are shifting to a more bold and simple approach, with heavy lines and shapes, and solid colors. This reduces the conf...
How does a flamethrower prevent the back flow of combustion as it shoots a stream of ignited fuel?	This device has no barrel - it's a torch with a two handed grip, plain and simple. Fuel and air mix outside of the fuel hose, which allows combustion. Inside the fuel hose, there is nothing but fuel, so combustion cannot occur.	[ "There are three methods of combustion: Dry forward, reverse and wet combustion. Dry forward uses an igniter to set fire to the oil. As the fire progresses the oil is pushed away from the fire toward the producing well. In reverse the air injection and the ignition occur from opposite directions. In wet combustion ...
Are there any bugs (like moths) who have evolved an 'immunity' to being confused by or drawn to light sources like porch lights? How about predators that started living near lights because of the abundance of food?	[Mediterranean Geckos](_URL_0_) , which now live almost exclusively on buildings, have been incredibly successful in spreading around the world. Man made structures offer vertical surfaces and hiding places. But they also often have lights and windows that attract insects. Although I have never seen a scientific study ...	[ "One of the best known modern examples of the role that evolution has played in insect defenses is the link between melanism and the peppered moth (\"Biston betularia\"). Peppered moth evolution over the past two centuries in England has taken place, with darker morphs becoming more prevalent over lighter morphs so...
If you were somewhere in space where the nearest star was thousands (or millions) of light years away would it be practically pitch black? Could you see your hand in front of your face?	Yes, there are places where it's that dark. In fact, most of the universe is that dark. If you were to suddenly appear somewhere else at a random place in the universe the odds are you would be in a place so dark you could not see any stars or galaxies. You could see galaxies if you had a telescope but with the naked e...	[ "BULLET::::- In the region of the constellation \"Perseus\", a star not visible to the naked eye, and 1,533 light years distant from Earth, explodes in a nova. The light from the star, now called GK Persei, will first be seen on Earth on February 21, 1901\n", "Distance to the star, 92 light years, is enough that ...
Why is there no mention of Alexander the Great in the bible?	As far as I know we simply will not have any particular reason to give to that. Now, [hillsonghoods](_URL_0_) mentions two good points in his post when an answer was removed: (a) there's not one canon (b) the process by which we end up with certain texts needs to be discussed. And he helpfully points out a passage in ...	[ "Alexander the Great (356BC-323BC) was a Greek king of Macedon and the creator of one of the largest empires in ancient history. He was tutored by the philosopher Aristotle and, as ruler, broke the power of Persia, overthrew the Persian king Darius III and conquered the Persian Empire. His Macedonian Empire stretch...
Why did the Visigothic and Ostrogothic cultures disappear? Why are there no more ethnic Goths in Europe?	Some of the Visigoths ended up ruling northern spain and parts pf southern france in the Visigothic Kingdom from the fifth through the eighth centuries (AD). They were able to secure this land partly via conquest and partly at the behest of the Romans. Their dominance was ended by the invasion of Spain by Islamic fo...	[ "The Goths and Vandals were linguistically assimilated to their Latin (Romance) substrate populations. Evidence exists that for 2nd- and 3rd-century Goths as well as for 4th- and 5th-century Lombards that significant population displacement throughout Roman-occupied Europe occurred. This quite likely contributed to...
why do devices such as phones take such little time to get to around 80%, and then take ages for the last 20%?	The charge stored in a battery when supplied by a constant voltage is exponential, depending on the type. ELI5: you’re at a public pool on a 105° degree day that only lets people in 1 at a time. They are gonna fill that pool up until they’re shoulder to shoulder, but each person goes to a random open spot in the poo...	[ "A cell phone's shelf life is only about 24 months for the average user. This means that newer cell phone models are constantly put up on the market to replace older ones. This is as a result of the rapid progression of technology in the mobile industry. According to Matt Ployhar of Intel, the industry is rapidly e...
How popular was classical music versus other songs in their mutual contemporary period? Was it based on class?	TL;DR: Classical music is music from the past, but it should not be assumed to be THE music of the past. It was mostly the music of the rich and powerful, and it was composed in specific styles and for specific contexts. Most people never wore fancy expensive formal clothes with elaborate jewelry, ate expensive exotic...	[ "Classical music became immensely popular in the nineteenth and twentieth centuries and was known across even the most rural sections of the country. It was defined by the tension between classical composer Martin Gjoka along with Fan Noli and Mikel Koliqi, who embraced national identity and added religious and fol...
why does adrenaline in certain circumstances give people super human strength? (being able to lift extremely heavy things off of people, etc.)	First its important to note that so called feats of "hysterical strength" are not scientifically recognized, although they are well documented. They clearly happen, but science has a hard time testing them, because its obviously very hard to reproduce in a lab. However, they have given small tests, like testing gr...	[ "Extreme sports trigger the release of the hormone adrenaline. This is a very powerful hormone as it can cause human beings to perform tremendous stunts of many sorts. However, with a bad mix of other hormones it can lead people to execute terrible actions. It is believed that the implementation of extreme sports o...
high gravity beer	Did you look at the wikipedia article? _URL_0_ It sums it up pretty consicely. Anyway, gravity refers to the specific gravity (density relative to water). Beers are considered high gravity when the density of the wort (beer before fermentation) is high. The density is of the wort is higher when there are more ...	[ "Measurement of the specific gravity of the beer has been used to estimate the strength of beer by measuring its density. Several different scales have been used for the measurement of gravity, including the Plato, Baumé, Balling, and Brix scales, with the Plato scale being the most common modern measure.\n", "Th...
Does the creation of the electricity used to fuel Tesla cars create just as much pollution as if they were gas powered?	You've asked about the electricity generation so I'll address that first. Then we can talk batteries and other aspects of EVs if you're interested. In the US power generation breaks down like this; - Coal 37% - Natural Gas 30% - Nuclear 19% - Hydropower 7% -- Other Renewable 5% -- Biomass 1.42% -- Geothermal 0.41% --...	[ "Electric cars have several benefits over conventional internal combustion engine automobiles, including a significant reduction of local air pollution, as they do not directly emit pollutants such as particulates (soot), volatile organic compounds, hydrocarbons, carbon monoxide, ozone, lead, and various oxides of ...
why did all the mice die in the mouse utopia experiment, as opposed to reaching a stable population	_URL_0_ Ignore my previous comment if anyone read it, I was very incorrect. Basically the tl;Dr for OP's question is that overpopulation conditions in animals (such as rats and mice) with social order of some kind results in disorientation in individuals there in, and causes pathological behavior changes ranging from...	[ "Mice with reduced expression of the mitochondrial antioxidant, [[SOD2]], accumulated oxidative damage and developed [[cancer]], but did not live longer than normal life. Overexpression of antioxidants reduced cellular stress, but did not increase mouse life span. The [[naked mole-rat]], which lives 10-times longer...
what happens when home owner dies and there is a mortgage left?	When a person dies, their property makes up the estate. Creditors can make a claim against the estate, and what is left after the debts are paid is distributed according the last will of the decedent. If the estate does not have enough assets to pay all of the debts, the creditors are out of luck regarding the rema...	[ "In a mortgage by demise, the mortgagee (the lender) becomes the owner of the mortgaged property until the loan is repaid or other mortgage obligation fulfilled in full, a process known as \"redemption\". This kind of mortgage takes the form of a conveyance of the property to the creditor, with a condition that the...
eli17: what's so great about "the great gatsby"?	The reason its great is because of Jay Gatsby. All the people around him are shallow and materialistic. Jay is the last American dreamer. Fitzgerald sees the 20's as a time when morals were decaying. The people who attend Jay's parties are social climbers. They have an insatiable desire for wealth and pleasure; they're...	[ "Gatsby has recently been read as a personification and representation of human-caused climate change, as \"Gatsby’s life depends on many human-centered, selfish endeavors\" which are \"in some part responsible for Earth’s current ecological crisis.\"\n", "Postmodern criticism of Gatsby seeks to place the novel a...
What were stationary/notebooks/writing materials like in colonial America?	You might find looking at the [digitized Jefferson papers](_URL_0_) useful. [The Farm Book](_URL_1_) should give you a good idea of what a casual "journal" type volume would have looked like. Not much like the Moleskine brand! Writing implement would have been a quill pen, which you can still buy very easily, and iron...	[ "A writing table (French \"bureau plat\") has a series of drawers directly under the surface of the table, to contain writing implements, so that it may serve as a desk. Antique versions have the usual divisions for the inkwell, the blotter and the sand or powder tray in one of the drawers, and a surface covered wi...
how does pintrest make money?	Investors is a channel where they get to keep the company running. With platforms like these, the norm is to create a solid user(fan) base and improve their services to a point where subscribers have invested enough content and won't mind seeing relevant ads.	[ "Her lucky pin continues to prove itself useful when she manages to pick a very profitable stock at one of the city's reputable investment corporations: Hendrick Courtney, Sr. and Sons. The firms manager, Hendrick 'Hank' Courtney Jr. is baffled by her performance, and lets her go on picking several more stocks to s...
if i was to travel away from the earth at sub-light speed then travel faster than light for a time, stop and look back at the earth, could i see myself leaving?	If you had a ship the size of a big city you probably could yes. If it was something the size of our current spacecrafts then no. For the same reason not even all the telescopes in the world put together could ever see something like the lunar rover we left on the moon.	[ "Since one might not travel faster than light, one might conclude that a human can never travel further from the Earth than 40 light-years if the traveler is active between the age of 20 and 60. A traveler would then never be able to reach more than the very few star systems which exist within the limit of 20–40 li...
how do online rewards sites know you’ve downloaded the app they are offering.	I am not sure about that exact use case (user level tracking), but in general there are a few ways that advertisers use to check which marketing campaign generates more app installs. One of the approaches is that the apps have a Tracking SDKs (like google analytics tags, but for apps) that can post back (send the url ...	[ "In most cases, incentive sites grant rewards for completing requirements. This usually requires viewing advertisements, signing up for a site, entering a PIN code (through a mobile device), purchasing trial products or full products or completing surveys. This in turn rewards the specified user in cash, points, ch...
can phones read your mind? on more than one occasion an ad or something on my phone has aligned with a previous thoughts i’ve had. explain?	It's called [Confirmation Bias](_URL_0_). You don't even think about the thousands and thousands of times that you've seen stuff on your phone that had nothing to do with anything you've been thinking about. But when there's a random match-up, you're amazed. Plus there are targeted ads. Stuff that you've been ...	[ "This shows, however, the same absent-minded muddle that would be revealed by someone who wondered whether telephones did not speak and think (for, tinny voice aside, they are apt to give very thoughtful replies), or who reasoned that books think (since they contain and communicate thoughts). The user is not in com...
How did Israel justify it's six-day war?	Following things build up before the attack: * Jordan and Egypt started a defense treaty, in late May * Egypt blocked the Straits of Tiran for Israel ships (Israel politicians stated before several times that this was a Casus Belli) * Egypt also forced the UNEF to retreat and * draw roughly 1000 tanks and 100.000 men...	[ "The 1967 war between Israel and the Arab states (the \"Six-Day War\") marked a major turning point in the history of both Israel and of Zionism. Israeli forces captured the eastern half of Jerusalem, including the holiest of Jewish religious sites, the Western Wall of the ancient Temple. They also took over the re...
Was Neil Armstrong not the first man on the moon?	Any successful mission to the Moon by the Soviets--even without an EVA--would have been enormous news that Moscow would have trumpeted around the globe. The idea that such a mission could have been kept secret is preposterous: missile launch detection satellites had been in orbit since the mid-1960s in the form of the ...	[ "In 1964, Neil Armstrong presented at the camp, and gave a lecture to the delegates describing NASA's plans to put a man on the moon. Five years later, just days before he was due to launch on Apollo 11, he sent a telegram to the camp expressing his commendation.\n", "On August 16, 1950, Aviation Midshipman Neil ...
how do binary explosives work, and how do they not explode if they are dropped?	They are explosives that come in two parts. Only combined do they become explosive. On their own they are inert.	[ "A binary explosive or two-component explosive is an explosive consisting of two components, neither of which is explosive by itself, which have to be mixed in order to become explosive. Examples of common binary explosives include Oxyliquit (liquid oxygen/combustible powder), ANFO (ammonium nitrate/fuel oil), Kine...
What is the Arminian Genocide?	Hi there! Part of your question is, essentially, ‘why didn’t I learn about this’. We’re happy to let the question stand, but there are a variety of reasons why you may find it hard to get a good answer to this question on /r/AskHistorians. Firstly, school curricula and how they are taught vary strongly between differe...	[ "The Herero and Nama genocide was a campaign of collective punishment that the German Empire waged against the Ovaherero, the Nama, and the San in German South West Africa (now Namibia). It is considered the first genocide of the 20th century. It occurred between 1904 and 1908.\n", "BULLET::::- The Herero and Nam...
Why can 2D objects rotate in just 1 axis but 3D objects can rotate in 3?	The number of rotation generators in D dimensions is D(D-1)/2. So D=2 gives 1, D=3 gives 3, D=4 gives 6 and so on. The rationale is as such: rotations in general shouldn't be though as happening around* an axis, but in a 2D plane. That with axes is a picture which is only meaningful in 3D, where a plane is also id...	[ "In 3D, equivalently it is the combination of a rotation and an inversion in a point on the axis. Therefore it is also called a rotoinversion or rotary inversion. A three-dimensional symmetry that has only one fixed point is necessarily an improper rotation.\n", "Rotations in 3D space are made mathematically much...
From the 1970s on, many cults are associated with religiously-motivated mass suicide. Why did this develop during the 70s--or was it in fact continuing an older tradition?	> From the 1970s on, many cults are associated with religiously-motivated mass suicide. Why did this develop during the 70s--or was it in fact continuing an older tradition? Your question is really two different, but related, questions. The first one is "how did cults become associated with mass suicide?" The second...	[ "In early 2000, followers of the religious movement perished in a devastating fire and a series of poisonings and killings that was initially considered a group suicide. It was later determined to be an orchestrated mass murder by group leaders after their predictions of the apocalypse failed to come about. In thei...
How common was it in Medieval times for people to name their swords?	I recently read "La Chanson de Roland" and "Le Couronnement de Louis/Charroi de Nîmes" in my medieval french lit. class. In both of those chansons de geste, both dating from the ~10th and ~11th century there are many named swords that are featured in the works. For instance, there are a number of passages about Rolan...	[ "In the Middle Ages, the sword was often used as a symbol of the word of God. The names given to many swords in mythology, literature, and history reflected the high prestige of the weapon and the wealth of the owner.\n", "From the testimony of Germanic mythology and the Icelandic sagas, swords could also be give...
How much power, if any, did the Senate still possess in the Byzantine Empire?	It's hard to say "during the Empire," because of how long the Empire was around. Generally, it just constantly lost power, sort of eventually forming more of a body of dignitaries and advisors than an actual legislative body. At least during the post-Justinian Byzantine times, it's rule was one of slowly losing power,...	[ "The senate continued to exist in Constantinople however, although it evolved into an institution that differed in some fundamental forms from its predecessor. Designated in Greek as \"synkletos\", or assembly, the Senate of Constantinople was made up of all current or former holders of senior ranks and official po...
how does it come that helicopters are so widely used in military even though they seem so vulnerable?	By the time you can see or hear an aircraft, it's already close enough to fire its weapons. It's more important to catch them with radar systems long before they get into firing range. That's where a helicopter has an advantage: It can fly very low to the ground, so low that objects on the ground and the earth's curvat...	[ "A military helicopter is a helicopter that is either specifically built or converted for use by military forces. A military helicopter's mission is a function of its design or conversion. The most common use of military helicopters is transport of troops, but transport helicopters can be modified or converted to p...
if dying of old age is not an actual cause of death then could one live indefinitely(not immortal) provided they have enough money and a constant supply of vital body parts to replace with?	No, you couldn't, and the reason is your DNA. Your DNA has bits of blank information on the end of it that are called telomeres. They act as a buffer to prevent damage to your DNA, because every time your cells reproduce, there is a risk of losing a very small amount of data from the resulting DNA. Think of them like a...	[ "The process of preserving and maintaining one's health throughout life is a matter of grave concern. At some point in every person's life, his or her health is going to decline regardless of all measures taken to prevent such a collapse. Coping with this inevitable decline can prove quite problematic for some peop...
crime explosion 1958 to present.	I have a degree in Criminal Justice, and criminology is a very vast field with many reasons within that could explain this answer. What type of crime rose specifically? Did some crime rise and some crime fall? Typically, around the holiday seasons, robbery will increase because citizens are looking to provide gifts ...	[ "Since the night of the explosion in 1951, five separate criminal investigations have been initiated and completed. The first investigation was headed by the FBI beginning on the night of the explosion and concluding in 1955. The second investigation was a joint investigation by the Brevard County Sheriff's Office ...
Hello, Historians! My history class is doing a writing assignment about pre-Depression era (1928) America and we need a little help.	The Library of Congress has a collection entitled ["Prosperity and Thrift: The Coolidge Era and the Consumer Economy, 1921-1929"](_URL_0_), which contains (among other things) several advertisements of products for sale in the '20s. That will certainly help you for the "Consumerism" part, but it is a useful resource i...	[ "The Forgotten Man: A New History of the Great Depression is a book by Amity Shlaes and published by HarperCollins in 2007. The book is a re-analysis of the events of the Great Depression, generally from a free market perspective. The book criticizes Herbert Hoover and the Smoot-Hawley Tariff for their role in exac...
how is malpractice handled in countries with universal healthcare?	It's actually pretty similar to how it's handle in the US. I'm from Canada so I'll talk about our system. Medical professional have a professional order which regulate their practice. They are the one that choose which professional can or can't do, they also are the one investigating any case of malpractice or things ...	[ "Outside of government intervention through subsidies, non profit organizations can also move a society towards the socially optimal outcome by providing free immunizations to developing regions. Without the ability to afford the immunizations to begin with, developing societies will not be able to reach a quantity...
what kind of things does mi6 and the secret service actually do?	The Secret Service is in charge of investigating counterfeiters, and provide protection services for the President, Vice President, Senators, Congressmen, and various other Dignitaries and their families in the US. MI6 is the British Foreign intelligence Service. They spy on other countries, and attempt to counter sp...	[ "MI6 is noted to use human intelligence to operate in different countries or Britain itself to protect the country from global affairs. However, this is usually mixed up with their brother agency MI5 which focuses on the security of Britain.\n", "The Secret Intelligence Service (SIS), commonly known as MI6, is th...
when dogs have so much better ears than us, why isnt their barking hurt them? isnt it extremly loudly for them?	Dogs have better ears means they can pick up sounds too quiet for us to hear or frequencies, it doesn't mean that all sounds they hear are amplified. A dog will hear sounds just as loud as us, but they will also pick up sounds we can't hear, that's what them having better hearing means.	[ "Chronic, excessive vocalization may be due to improper socialization or training, stress, boredom, fear, or frustration. Up to 35% of dog owners report problems with barking, which can cause disputes and legal problems. The behavior is more common among some breeds of dog, such as the Shetland Sheepdog, which are ...
Transition from prehistory to history: emergence of large-scale well organised societies before the invention of writing?	I have a more specific reply to your question below, but first I'd like to talk about the question itself a little bit. Musings You have brought up several big issues here, many of which are extremely contested. The first big one is this; does 'history' truly require written records? As archaeology has grown more...	[ "Writing systems were preceded by proto-writing, which used pictograms, ideograms and other mnemonic symbols. Proto-writing lacked the ability to capture and express a full range of thoughts and ideas. The invention of writing systems, which dates back to the beginning of the Bronze Age in the late Neolithic Era of...
Was the Reconquista considered more secular or religious at the time?	I am surprised no one has tackled this yet. This is not my exact area of expertise but I will give it a crack. First we have to ask when was it considered more secular or religious? > "There is a corresponding change in the notion of reconquest. At the start the ideal is to restore a united Spain under the kings of...	[ "\"Reconquista\" resulted in expulsion of the Moors from the Algarve, in the institutionalization of Christianity and the building of churches. During the Middle Ages, the parish was officially referred to as \"Nossa Senhora da Luz\".\n", "The \"Reconquista\" was a war with long periods of respite between the adv...
why do the southern states have the highest rates of obesity in america?	There are several reasons. 1. Poverty. As others mentioned, states like Mississippi and Alabama have very high poverty rates. Obesity and poverty are correlated strongly in the U.S. 2. Cuisine. Southern food isn't known for being terribly healthy. While Southerners don't eat fried chicken for every meal, the sort of ...	[ "Nine Southern states have obesity rates exceeding thirty percent of the population, the highest in the country: Mississippi, Louisiana, West Virginia, Alabama, Oklahoma, Arkansas, South Carolina, Kentucky, and Texas. Rates for hypertension and diabetes for these states are also the highest in the nation. A study r...
what classifies something as a plastic and how can the same type of plastic (e.g polyester) be used from slick, waterproof shirts to fluffy blankets?	Plastics are synthetic or partly synthetic polymeric materials. (Basically materials made from enormously big molecules, compared to other materials.) As to why is there a wide range of plastics. Simply because we spent the last century with trying to make new kinds of plastics that could be applied in different situ...	[ "Plastic products are printed with numbers 1–7 depending on the type of resin. Type 1 (polyethylene terephthalate) is commonly found in soft drink and water bottles. Type 2 (high-density polyethylene) is found in most hard plastics such as milk jugs, laundry detergent bottles, and some dishware. Type 3 (polyvinyl c...
Has an invasive or agriculturally-destructive species ever been intentionally introduced to a rival country, with the intention of causing harm?	This does not quite fit the bill of "rival country" but in 1989, a self described "ecoterrorist group" known only as "The Breeders" took credit for the recent infestation of California by medflies, which began destroying crops. Opinion is divided today as to whether it was a real attack, an out of control prank, or if ...	[ "In cases of massive and severe infection of invasive pests, techniques of pest control are often used in combination. An example is the emerald ash borer, \"Agrilus planipennis\", an invasive beetle from China, which has destroyed tens of millions of ash trees in its introduced range in North America. As part of t...
is the "fiscal cliff" actually bad for our economic recovery?	Probably really bad for the economy. It does a lot of things all at once. 1- End Bush Era Cuts, 2- Cuts in Defense Spending, 3- End of the payroll tax holiday, 4- Cut in Unemployment Benefits, 5- Cut in Medicare payments to doctors. A lot of people will lose their jobs because of point 2. (Military contractors and ...	[ "The \"fiscal cliff\" refers to December 31, 2012, the date of the expected implementation of government spending reductions and expiration of a large number of tax cuts, many of which were the tax cuts enacted under George W. Bush and extended by President Obama. In a report released in May 2012, the Congressional...
what makes a coach watch or something designer worth so much money?	They do tend to be very high quality. That is how they make a name for themselves and then on top of that they have become status symbols and the fact that they are expensive makes them more valuable to some people "I want people to know/think I'm rich so I buy things people know are expensive"	[ "Millennium Luxury Coaches is a Central Florida based manufacturer of custom luxury motor coaches, built at their 100,000 square foot facility in Sanford. All coaches are built using the Prevost commercial bus chassis. Millennium has designed custom coaches for business owners, celebrities and pro athletes which ha...
Scientists plan on taking the first picture of a black hole. But how?	You're correct that black holes emit nothing visible to our cameras. All they mean is that they will take a picture of where the black hole is, not that they will image photons emitted from it. > So how does one take a picture of something that by definition is impossible to see? At this point we can start nitpicki...	[ "studies into black holes with the goal to construct a black hole camera using the Event Horizon Telescope. This would allow testing of general theory of relativity by creating an image of the black hole shadow.\n", "The first image of a black hole, at the center of galaxy Messier 87, was published by the EHT Col...
how a ufc fighter can drop 26lbs in 6 days to make weight, then manage to fight the next day?	Dropping that much weight in such a short time takes an enormous physical toll. An average person would be physically spent, however, these fighters are in phenomenal physical shape to begin with. Think of the most fit person you know and multiply it by ten. Yes, it affects his strength and physical abilities, but si...	[ "Tara LaRosa (127.6 lbs) and Lacey Schuckman (106.2 lbs) failed to make weight at the weigh in. Schuckman was able to get within 1 pound of her 105 weight class limit within the next two hours and was fined 10% of her purse. LaRosa was not able to get within one pound of 125 pounds within two hours and was fined 25...
how does a musical score in a film help elicit such specific emotional response in viewers?	It's partially something you learn, partially innate, but it's also the result of a long experience in eliciting emotions through music. Wrt. learning, let's look at Western movies. We were not born with the association of a certain rhythm with riding a horse. But composers have been using it for a long time, and by n...	[ "In regards to issues with connectivity, it is important to consider the musical score of composite films. Much like visual repetition or thematic similarities, the score offers another medium through which stories can be linked. Rather than leaving viewers with content to process, decode, intellectualize and then ...
How do we know ice core samples get older as we go deeper?	The most obvious answer is the older stuff had to freeze to allow the newer stuff to freeze on top of it. We can further show this by: Oxygen for example normally exists with 8 protons and neutrons giving O16. It can however exist in an isotope with 8 protons and 10 neutrons giving O18. In the same why Hydrogen can e...	[ "In 2016, cores were retrieved from the Allan Hills in Antarctica in an area where old ice lay near the surface. The cores were dated by potassium-argon dating; traditional ice core dating is not possible as not all layers were present. The oldest core was found to include ice from 2.7 million years ago—by far the ...
Physics: How are special relativity, general relativity, and e=mc^2 related to one another?	E=mc^(2) is a result found from special relativity that tells us that mass is a form of energy. Special relativity: The consequence of light having the same speed relative to any observer. Explains how to translate what one non-accelerating observer measures to what another non-accelerating observer measures. General...	[ "Formally, special relativity combines the electric and magnetic fields into a rank-2 tensor, called the \"electromagnetic tensor\". Changing reference frames \"mixes\" these components. This is analogous to the way that special relativity \"mixes\" space and time into spacetime, and mass, momentum, and energy into...
Synapses are the gaps between the axon terminal of one neuron and the dendrites of another neuron, correct? So, effectively, synapses are gaps between neurons? In that case, what conducts the travel of neurotransmitters through the synapses, and how is the nervous system held together?	There are broadly two types of synapses. The type you are thinking about are strictly called "chemical synapses". Yes, at the simplest level they are very small gaps between two very specialized parts of two neurons. Not just any gap will do, there are specialized structures on both cells both in the synapse and s...	[ "An axon can divide into many branches called telodendria (Greek–end of tree). At the end of each telodendron is an axon terminal (also called a synaptic bouton, or terminal bouton). Axon terminals contain synaptic vesicles that store the neurotransmitter for release at the synapse. This makes multiple synaptic con...
how hiv is transmitted from a woman to a man	Blood. Micro cuts in her vagina and micro cuts on your penis.	[ "The most common form of transmissions of HIV is through blood, semen, pre-ejaculation, rectal mucus, vaginal fluids and breast milk. Therefore, women need to be extremely cautious when engaging in sexual activity as well as if and when falling pregnant. Often, behaviours that lead to women contracting the HIV viru...
From where did Roman legionnaires get their equipment?	The Romans, at least in the late Republic and Empire, had very sophisticated logistics. They had to, they were supporting a large army spread out throughout Europe and North Africa and into Asia. Jonathan Roth's The Logistics of the Roman Army at War covers this in detail. Roman military campaigns generally pre-pl...	[ "Roman legionaries were recruited from Roman citizens under the age of 45. This meant that while Roman legionaries were first predominantly made up of recruits from Roman Italy, more legionaries were recruited from the provinces as time went on. As legionaries moved into newly conquered provinces, they served to he...
How much more powerful were the battleships Yamato and Musashi in comparison to other WW2 era battleships?	Going off of numbers alone, Yamato and her sister Musashi are very impressive ships. Their nine [46 cm (18 inch) guns](_URL_3_) were the largest guns to ever be fitted to any class of battleship. In comparison, the Iowa-class battleships, commissioned after Yamato and Musashi, stuck with [16 inch guns.](_URL_1_...	[ ", named after the former Japanese province, was one of three s built for the Imperial Japanese Navy (IJN), beginning in the late 1930s. The \"Yamato\"-class ships were the heaviest and most powerfully armed battleships ever constructed, displacing almost fully loaded and armed with nine main guns. Their secondary ...
what's the advantage of a really long lease (1000s of years) as opposed to actually buying a property?	It's not there as a benefit to the seller but to the owner of the property. If they sell it, they lose it forever & have no control over it. If they lease it, they can impose conditions on it. Like, let's say you want somebody to make beer in your town. You give them a great piece of land. After 5 years, they de...	[ "Tenancies above a couple of years are normally called leases and tend to be long; if more than 7 years a new leasehold estate must be registered. These are governed by few of the above rules and are in longer examples deliberately more akin to full ownership than tenancies, in general. They seldom require a sizeab...
France has detonated over 210 nuclear devices to Britain's 45. Why did France pursue a much more aggressive nuclear testing regime than Britain?	A number of reasons really. They didn't sign on to the [Partial Test Ban Treaty](_URL_0_) in 1963, so they weren't under any international treaty regulation. France has 75% nuclear energy, so they had fissile material in abundance. Being so heavily invested in nuclear energy is (or was) a huge source of pride for Franc...	[ "France tested its first nuclear weapon in 1960 (\"Gerboise Bleue\"), based mostly on its own research. It was motivated by the Suez Crisis diplomatic tension \"vis-à-vis\" both the Soviet Union and its allies, the United States and United Kingdom. It was also relevant to retain great power status, alongside the Un...
How does gene therapy/crispr affect every single cell in the body?	They don't. Getting CRISPR to the right tissue is a completely separate problem, and it's not solved right now. Until it is, CRISPR has research value but not therapeutic value. Delivering CRISPR to a single cell changes that cell and cells created from that cell by cell division. This means that delivering CRISPR to...	[ "In 2016, the United States Food and Drug Administration (FDA) approved a clinical trial in which CRISPR would be used to alter T cells extracted from people with different kinds of cancer and then administer those engineered T cells back to the same people.\n", "The first clinical trial involving CRISPR started ...

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