Split (2)

train · 226k rows

question stringlengths 3 301	answer stringlengths 9 26.1k	context list
why are pumpkins carved for halloween?	In the rural areas where Halloween first became popular, people would carve out turnips or gourds and put candles in them as lanterns when they went from house to house pretending to be spirits of the dead. Carving faces in them made them creepier and more like a wandering spirit. Pumpkins eventually became popular bec...	[ "Pumpkins are commonly carved into decorative lanterns called jack-o'-lanterns for the Halloween season in North America. Throughout Britain and Ireland, there is a long tradition of carving lanterns from vegetables, particularly the turnip, mangelwurzel, or swede. The practice of carving pumpkins for Halloween ori...
why is conservatism/republicanism so intertwined with christianity in america?	_URL_0_ _URL_2_ _URL_1_ Basically christian denominations in the 1960's didn't like increasing secularism and the counter culture(hippies, liberalism, drugs). And while traditionally they shunned being involved in politics. They started to get involved starting in the early 1970's. And ever since, protestant christia...	[ "The emergence of the \"Christian right\" as a political force and part of the conservative coalition dates from the 1970s. According to Cambridge University historian Andrew Preston, the emergence of \"conservative ecumenism.\" bringing together Catholics, Mormons, and conservative Protestants into the religious r...
- how bets are placed during illegal fights like we see in the movies?	Someone at the event is a bookie. people yell out saying they want to put money on said action. The bookie can make odds and start taking bets, or choose not to take the action	[ "Bets were made back then as is still customary to this day. Bets were made on the results of the fight, on who'd draw the first blood, or on who would score the first knockdown. There were rules, but they were designed to accommodate gambling, the public, and those who organized the fight. The boxers themselves we...
Is eating raw food at all healthier?	Depends on a couple of things: the food itself, the way it would have been prepared and what one means with healthy. Raw egg for instance. Cooking has no negative influence on the quality or bioavailability of the protein - raw or boiled, all the same. However, raw eggs can contain bacteria in which case heating it up...	[ "One review stated that \"Many raw foods are toxic and only become safe after they have been cooked. Some raw foods contain substances that destroy vitamins, interfere with digestive enzymes or damage the walls of the intestine. Raw meat can be contaminated with bacteria which would be destroyed by cooking; raw fis...
If a regime resembling Nazi Germany arose today, how would economic warfare change the conflict?	This roughly fits into the [no current events rule](_URL_0_) that we use since it's asking about something today. Perhaps reword the question in another way.	[ "During the Hitler era (1933–45), the economy developed a hothouse prosperity, supported with high government subsidies to those sectors that tended to give Germany military power and economic autarky, that is, economic independence from the global economy. During the war itself the German economy was sustained by ...
Is the story about the Rothschilds gaining wealth through knowing Napoleon had lost true?	Short answer? Maybe. At the least, they were probably aware of the outcome of Waterloo quickly enough to make a profit from it. The Long Answer, though, is a little different. There's literally no way that he could have made a big enough profit on war bonds to account for the kind of stuff they claim - the market itsel...	[ "Historian Niall Ferguson agrees that the Rothschilds' couriers did get to London first and alerted the family to Napoleon's defeat, but argues that since the family had been banking on a protracted military campaign, the losses arising from the disruption to their business more than offset any short-term gains in ...
How did the modern German state of Saxony get its name? Wasn't Saxony originally near modern-day Denmark? How did a state in eastern Germany bordering the Czech Republic end up with the name Saxony?	In this answer I will look at the geographical movement of the political entity known as Saxony. The history of Saxony can be divided into 5 periods Old Saxony (also known as pre-ducal saxony), Duchy of Saxony, Electorate of Saxony, Kingdom of Saxony, and Free State of Saxony. During the time of Old Saxony, unlike all...	[ "The name of Saxony derives from that of the Germanic tribe of the Saxons. Before the late medieval period, there was a single Duchy of Saxony. The term \"Lower Saxony\" was used after the dissolution of the stem duchy in the late 13th century to disambiguate the parts of the former duchy ruled by the House of Welf...
If you had unlimited time and resources, would it be possible to walk on the bottom of the marinas trench?	Short answer no. The physiology of a human will never be able to simply "acclimate" to the absolutely extreme pressures. [This blog post regarding travel to Challenger Deep](_URL_0_) from a marine biologist does an excellent job of 1) describing the immense pressure at those depths and 2) the array of physiological eff...	[ "Percolation trenches are often used to treat runoff from impervious surfaces, such as sidewalks and parking lots, on sites where there is limited space available for managing stormwater. They are effective at treating stormwater only if the soil has sufficient porosity. To function properly, a trench must be desig...
why do whips make that big “wuh-psssh!” sound?	The tips of the whip actually break the speed of sound. The crack of the tip is making a sonic boom.	[ "There are two types of whips. The first has two planks of wood connected by a hinge, with a handle on each. The percussionist holds the instrument by the handles and hits the two pieces of wood together, creating a loud whip noise. The other type also has two planks of wood, one longer than the other, with one han...
Learning about Physics from scratch?	'Fundamentals of Physics' by Halliday, Resnick, and Walker is a great introductory text that covers most basic areas of physics. That would be my personal recommendation.	[ "The study and practice of physics is based on an intellectual ladder of discoveries and insights from ancient times to the present. Many mathematical and physical ideas used today found their earliest expression in ancient Greek culture, for example in the work of Euclid, Thales of Miletus, Archimedes and Aristarc...
what do we reference a unit of measure to? how do we know an inch is an inch?	Right now, the meter is based on the speed of light in a vacuum, which is absolute and relatively easily reproducible. "the length of the path travelled by light in vacuum during a time interval of 1/299,792,458 of a second."	[ "The inch (abbreviation: in or ″) is a unit of length in the (British) imperial and United States customary systems of measurement. It is equal to yard or of a foot. Derived from the Roman uncia (\"twelfth\"), the word \"inch\" is also sometimes used to translate similar units in other measurement systems, usually ...
how do games make you smarter?	Usually RTS games make you think critically and use resources efficiently. MOBAs teach you to deal with assholes.	[ "Cognitive skills can be enhanced through repetition of puzzles, memory games, spatial abilities and attention control. Most video games present opportunities to use these skills with the ability to try multiple times even after failure. Many of these skills can be translated to reality and problem solving. This al...
why do muslims believe it is empowering for women to cover their bodies?	I don't see how anyone can think it is empowering or not feel like an object when you literally have a sheet over you like some entrepreneur's big new invention.	[ "Al-Munajjid states that Muslim women are required to cover their entire body including the face (only showing eyes) and hands. This ruling is obligatory and does not vary depending where you are. Women are required to stay in their houses unless they are in the company of a mahram and are forbidden to drive cars a...
What was a "Turk" to peoples of the 13th-16th centuries?	As an exonym, Early Modern Europeans often used the word "Turk" to describe any Levantine or Balkan Muslims, regardless of their looks or geographical origin. In the context of the time, it was more of a religious and political identity than an ethnic or linguistic identity that it is today. Essentially, "Turk" was a...	[ "The first known mention of the term \"Turk\" (Old Turkic: 𐱅𐰇𐰼𐰰 \"Türük\" or 𐱅𐰇𐰼𐰰:𐰜𐰇𐰛 \"Kök Türük\" , Old Tibetan: duruggu/durgu (meaning \"origin\"), Pinyin: Tūjué, Middle Chinese (Guangyun): ) applied to a Turkic group was in reference to the Göktürks in the 6th century. A letter by Ishbara Qaghan to E...
why is the average temperature of the earth still rising due to global warming even as holes in the antarctic ozone layer are healing?	These 2 things are unrelated. Global warming is mostly caused by an excess of greenhouse gasses. The holes in the ozone layer were caused by our use of CFCs which damage the ozone layer. Since CFCs were banned the ozone layer has been able to recover.	[ "BULLET::::- Chemistry-climate models predict that springtime Antarctic ozone levels will be increasing by 2010 because of projected decreases of halogens in the stratosphere. A return to pre-1980 total column ozone amounts in the Antarctic is expected by the middle of this century.\n", "The 2010 report found, \"...
why do websites such as pandora need to pay a licensing fee to play an artist's song, but websites like youtube don't have to?	Youtube is just hosting the videos. If an artist's "official" youtube channel posts a full song, the artist is already involved, and thus Youtube doesn't have to pay a fee. If the artist is not involved, they can send a claim to youtube, and youtube will take the song down - thereby not having to pay for use of the son...	[ "In 2014, Pandora signed an agreement with some music copyright owners for lower royalties in exchange for more frequent streaming of songs. Though not illegal, this practice raised comparisons to payola, which is illegal payment for airplay on terrestrial radio.\n", "Some games which have used licensed music, su...
where does the bank interest on a savings account actually come from?	When you deposit $1000 in a bank account earning 1%, they take most of that money and loan it out to someone else at, say, 3%. 1% goes to you, and 2% goes to the bank, to cover overhead, defaults, and to provide profit to the shareholders.	[ "A savings account is a deposit account held at a retail bank that pays interest but cannot be used directly as money in the narrow sense of a medium of exchange (for example, by writing a cheque). These accounts let customers set aside a portion of their liquid assets while earning a monetary return. \n", "A sav...
what is the "hierarchy" and difference between the different kinds of courts i hear about?	Assuming you are talking about the United States, there are two types of courts - Federal and State. Courts, broadly, are either courts of first instance (the first court that you file a lawsuit or start a trial in,) or appellate courts (courts that hear appeals from lower courts.) Some courts are courts of first ins...	[ "The hierarchy consists of a variety of courts and tribunals at both the federal and state and territory levels, with the High Court being the highest court in the Australian judicial system. A single body of Australian common law is applied in the various Australian courts, and ultimately determined by the High Co...
how is the futures trading market different from gambling or betting?	Gambling is totally random based on odds of things happening. Futures are still based on the same fundamentals that stock purchases are made. There is some additional risk because you are adding a time component, but you are still using the available information about the underlying asset and economy as a whole in orde...	[ "Betting exchanges compete with the traditional bookmaker. They are generally able to offer punters better odds because of their much lower overheads but also give opportunities for arbitrage, the practice of taking advantage of a price differential between two or more markets. However, traditionally, arbitrage has...
If a moderately well-off citizen of ancient Rome wanted to take his family on a vacation, what sort of options would be open to him?	not discouraging anyonen with specific information about vacation options in ancient Rome, but FYI there have been several questions about vacations in ye olde days. I've taken this opportunity to do a general roundup (with an eye to adding them to the "popular questions" wiki); I've indicated which ones include respon...	[ "It appears to have early become a favorite resort with the wealthy Romans as a place of retirement and pleasure; thus we find that Pompey the Great had a villa there, and Julius Caesar also, where he landed on his return from Africa, and at which all the nobles of Rome hastened to greet him. Another is mentioned a...
To what extent were African Americans involved in Marxism and what were Soviet opinions of African Americans?	Whilst this is only an incomplete answer, the career of the Trinidadian journalist [George Padmore] (_URL_2_) might be of interest. He became a communist whilst studying medicine in the USA, and his eloquence and intelligence gave him the opportunity to visit Moscow for the 1929 Communist International. After the confe...	[ "The Communist Party USA, ideologically committed to foster a socialist revolution in the United States, played a significant role in defending the civil rights of African Americans during its most influential years of the 1930s and 1940s. In that period, the African-American population was still concentrated in th...
Is the Human Brain Turing Complete?	Your question as I read it is different from your description. Turning complete basically means you can calculate what a Turing machine can calculate, which your brain can do. In your description you ask if the brain could compute in the same way as a computer. Yes and know, you can calculate the same thing, but not in...	[ "Turing did not claim that the human mind really is a digital computer. More modestly, he proposed that digital computers might one day qualify in human eyes as machines endowed with \"mind\". However, it was not long before philosophers (most notably Hilary Putnam) took what seemed to be the next logical step—argu...
why do so many different species (whales, humans, pigeons) have such similar bodily structures (2 eyes, 2 ears, digestive tract)?	In most cases, common descent - we all share an ancestor that, however long ago, had two light-sensing organs or a digestive system or whatnot. In quite a few cases, convergent evolution - two different species develop a trait independently from one another due to similar selection pressure or to "solve" a similar pro...	[ "There may be differences in pupil shape even between closely related animals. In felids, there are differences between small- and large eyed species. The domestic cat \"(Felis sylvestris domesticus)\" has vertical slit pupils, its large relative the Siberian tiger \"(Panthera tigris altaica)\" has circular pupils ...
Why does carbon monoxide bond so strongly to iron in hemoglobin?	Oh I'm very happy to answer this question. So this question delves into organometallic chemistry. If you look at the structure of CO, there's a triple bond between carbon and oxygen, and surprisingly the carbon has a lone pair and is the anionic end while the oxygen has only a single lone pair and is the cationic end. ...	[ "The binding of oxygen is affected by molecules such as carbon monoxide (for example, from tobacco smoking, exhaust gas, and incomplete combustion in furnaces). CO competes with oxygen at the heme binding site. Hemoglobin's binding affinity for CO is 250 times greater than its affinity for oxygen, meaning that smal...
why is bob my uncle?	“Bob's your uncle” is a way of saying "you're all set" or "you've got it made." It's a catch phrase dating back to 1887, when British Prime Minister Robert Cecil (a.k.a. Lord Salisbury) decided to appoint a certain Arthur Balfour to the prestigious and sensitive post of Chief Secretary for Ireland. Not lost on the Brit...	[ "Uncle (1964) is a children's novel written by J. P. Martin, the first book of six forming the \"Uncle\" series. It is named after the main character, a rich philanthropic elephant who lives in a huge fantastical castle populated by many other eccentric animals and people. It was illustrated, like the others in the...
why are the violent drug cartels not considered terrorist groups?	A "terrorist" is a person who is trying to use terror (fear) to influence politics. The drug cartels aren't in it for the politics. They're in it for the money. So that makes them not terrorists, just regular criminals.	[ "The drug cartels have fought back violently against the military and have used violence to strke fear on the civilian population. In addition, journalists have also been targets of the drug gangs when they have reported on their criminal activities.\n", "In a CBS news article, the Chief of Operations for the US ...
Assuming this is not staged somehow, can someone explain the physics of how this is possible	It's not staged. The key factor is that the table sways somewhat from each metronome. This swaying allows each metronome to interact and interfere with the others and this tends to push them into synch. It takes some pretty complex differential equations to prove this, but when you work it out, the result is that th...	[ "BULLET::::- Forum Theatre - The actors either create a planned improvisation or create a piece spontaneously, as it is performed the audience can either stop the action to suggest changes or take over from the actors on stage to change the direction of the performance. Quite often this is used as an exploration to...
how do competitive eaters fit all the food they eat in their stomach?	You eat massive amounts in training and it stretches out your stomach. The stomachs of competitive eaters are much more elastic than normal people.	[ "The Great American Eat Off - a show that pits two average eaters against each other to see who can eat the fastest, while raising awareness for charity and then brings in a professional competitive eater to beat the winning time, raises the stakes for competitive eaters by incorporating various challenges and obst...
can the president be arrested?	Probably not. It's not settle law because normally the President isn't a criminal. _URL_0_ President Grant was once given a speeding ticket though.	[ "General Order № 2 – The President directed the Minister of National Defense to arrest or cause the arrest and take into his custody the individuals named in the attached list and to hold them until otherwise so ordered by the President or by his duly designated representative, as well as to arrest or cause the arr...
Why did so many bombs not explode when they were dropped on Vietnam/Laos?	There is always a base failure rate with any technology. Bombs are no different in this respect (and many of them are more complicated than you might realize, and complication often adds new failure modes). So let's imagine you have a bomb that works 99.9% of the time — that is way higher than the success rate of many ...	[ "During the Vietnam War, Laos was the target of the heaviest US bombing campaign, making Laos the most bombed country in history: from 1964 until 1973 more than two million tonnes of bombs were dropped, including 260 million cluster munitions. An estimated 30% of the bombs dropped failed to detonate as intended. Un...
how come the percentage of left handed people is so much higher in the mlb than in real life?	Left-handed hitters are a couple of steps closer to first base. Left-handed first-basemen have their glove hand in a better position to catch pickoff throws. Left-handed pitchers have a better view of the runner on first.	[ "For reasons that continue to spur debate, it is historically the case that most right-handed pitchers succeed at higher rates against right-handed hitters than against left-handers, and that most left-handed pitchers succeed at higher rates against left-handed hitters than right-handers.\n", "BULLET::::- In base...
When does one use Hilbert Space instead of Euclidean Space?	> * A Hilbert Space has infinite dimensions > * An Euclidean Space has finite dimensions This is incorrect. A Hilbert Space is any vector space that 1.) Has an Inner Product and 2.) Is "complete", which means limits work nicely. In particular, the vector space R^(n) with the standard dot product is a finite dimen...	[ "The mathematical concept of a Hilbert space, named after David Hilbert, generalizes the notion of Euclidean space. It extends the methods of vector algebra and calculus from the two-dimensional Euclidean plane and three-dimensional space to spaces with any finite or infinite number of dimensions. A Hilbert space i...
how do computers recognize different styles of code?	They don't. Computer actually have only one style of native code. everything else needs to be translated into that. Usually this is done with a compiler a program that turns human readable code into machine code. Sometimes for code in programming languages that are used for scripting, instead of compiling the code o...	[ "Software classification is the process of identifying similarities between different software binaries (for example, two different versions of the same binary) used to detect code relations between software samples. This task was traditionally done manually for several reasons (such as patch analysis for vulnerabi...
why do different engines need different fuels? what is the difference between these fuels?	So, you put fuel into an engine and the engine then also takes in air, and then either the spark plug sparks it, causing the fuel to combust OR with diesel fuel, compressing the fuel causes it to ignite on its own. The difference in octane rating (89, 91, 93 etc) is that the higher the rating, the less it "knocks," or,...	[ "Fuel variety plays a significant role in the dynamics and characteristics of engine performance, the operating cost of an aircraft and ultimately the safety and reliability of an engine. Conventional fuels consist of jet fuel and AVGAS (aviation gasoline), which differ from automotive engine fuels. These are fuels...
why do we go from 11am to 12pm then 1pm and 11pm to 12am then 1am. shouldn't it be 11pm, 12pm, 1am?	AM stands for ante-meridian. PM stands for post-meridian. Meridian in both these contexts talking about noon	[ "Noon (also midday or noon time) is 12 o'clock in the daytime, as opposed to midnight. The term 12 p.m. (for post meridiem, and also written as 12 pm or similar variations thereof) is sometimes used for noon.\n", "In the United States and Canada, digital clocks and computers commonly display 12 a.m at midnight. T...
How fast is our galaxy traveling through the universe?	> [Speed relative to CMB rest frame: 552 km/s.](_URL_0_) Just a note, there is no center of the Universe. Our speed relative to the [cosmic microwave background radiation](_URL_1_) is the closest we have to the idea of our "speed through the Universe." The rest frame of the CMB is the frame of motion in which the ...	[ "The Andromeda Galaxy is approaching the Milky Way at about as indicated by blueshift. However, the lateral speed (measured as proper motion) is very difficult to measure with a precision to draw reasonable conclusions: a lateral speed of only 7.7 km/s would mean that the Andromeda Galaxy is moving toward a point 1...
amiibos	They sell out so fast mostly because they are highly collectible (like limited edition action figures and other related toys). There are people who like to collect large numbers of them even though they don't actually use most of them for their intended purpose. Amiibos are basically figurines of Nintendo video game c...	[ "Amikumu ( ; ) is a cross-platform app for smartphones (Android and iOS) which can be used to find people nearby who speak or learn the same languages as the user. The app was launched for Esperanto speakers on 22 April 2017 and for speakers of all languages during LangFest in Montreal on 25 August 2017. On 9 Augus...
how do electric vehicles cut down on carbon emissions? i know they don't use gas but don't we still have to burn coal etc to power them up?	Power from power plants is often times much more efficient. It’s like how BNSF advertised that, by scale, a train gets roughly 340mpg compared to other shipping methods like trucks. Also, power comes from multiple sources including clean sources like hydro, wind, solar, nuclear, etc. Tesla’s Gigafactory is also power...	[ "By converting the lost heat into electricity, ATEGs decrease fuel consumption by reducing the electric generator load on the engine. ATEGs allow the automobile to generate electricity from the engine's thermal energy rather than using mechanical energy to power an electric generator. Since the electricity is gener...
Aliens through history	It's modern. Before aliens there were demons, witches and so on. Although not a historical work, Carl Sagans Demon haunted world deals very much with alien abductions, how they came about and what was in their place before anyone thought about aliens.	[ "BULLET::::- Enigma (1986, ) : Set 150 years after the events of the first book, the 'aliens' turned out to be human and considered themselves to have been colonized from Earth in the distant past. The Unified Space Survey has been established to make contact with other remnants of the first colonization and to det...
deficit goes down but debt ceiling goes up. why?	If you spend $1000 in a year, and you earn $500 in that same year, your deficit is $1000 - $500 = $500. You have to borrow $500 to make it up. Now imagine next year you spend $900 and make $600. Your deficit is $300, which is lower than the previous years'. But you still have to borrow $300 which, when added to the ex...	[ "In a press conference held on January 14, 2013, President Obama stated that not raising the debt ceiling would cause delays in payments including benefits and government employees' salaries and lead to default on government debt. President Obama urged Congress to raise the debt ceiling without conditions to avoid ...
when you shake a bowl of nuts, why do the larger ones come to the top?	Because the gaps between items are small and the small items find it easier to fall through those small holes.	[ "BULLET::::- When a container of mixed nuts is opened after it has been shaken, the larger nuts tend to be on top. This phenomenon is known as the \"Brazil nut effect\" in the study of granular materials.\n", "BULLET::::- The center of mass of the whole system (containing the mixed nuts) in an arbitrary state is ...
Is there a theoretical limit to how many immunities you can acquire? Does acquiring new immunities reduce the immune response of previously acquired immunities?	No, there is no theoretical limit, however not all immunity is lifelong and immunity will fade if you are not re-exposed to the pathogen. When you become immune to a pathogen, a really complex process is taking place involving pre-existing immune cells, genetic recombination, innate responses, and a host of other thin...	[ "Adoptive immunotherapy seeks to expand a population of the body's T-cells that will recognize a specific tumor antigen. T-cells can be harvested and then expanded and genetically manipulated to recognize certain tumor markers. In one case, a patient with advanced epithelioid sarcoma who had failed multiple therapi...
why can dvd movies only so videos at a low resolution but games on a dvd can hold hd textures?	A movie needs to store every frame, while a game actually generates new frames as you play it. The only things that need to be on the disk are the raw resources from which the frames are generated, and those can be heavily re-used. If a texture is used in ten hours of gameplay, it's still the same single texture that o...	[ "DVD-10 discs fell out of favor because, unlike dual-layer discs, they require users to manually flip them to access the complete content (a relatively egregious scenario for DVD movies) while offering only a negligible benefit in capacity. Additionally, without a non-data side, they proved harder to handle and sto...
Did the Nazis ever specifically aim to bomb British landmarks? Or vice versa?	The [Hermannsdenkmal](_URL_0_) (in memory of Arminius' victory at the Teutoburg Forest) was riddled with [bullet holes](_URL_1_) (click on the picture to enlarge) by passing Allied planes. I suspect that was more a case of "celebratory gunfire" than the result of any planning though. The letter quoted on this page ...	[ "Public opinion in Britain throughout the 1930s was frightened by the prospect of German terror bombing of British cities, as they had started to do in the First World War. The media emphasized the dangers, and the general consensus was that defense was impossible and, as Prime Minister Stanley Baldwin had said in ...
why are we not in full control of our brains although we are the host?	Imagine if you could alter how the engine in your car performs at any moment. Chances are, you'd tweak settings that might ruin the engine permanently. Same thing with your operating system -- there are settings you can't change (or have very restricted access to) because messing around with those settings can cause a ...	[ "For example, philosopher Daniel Dennett has proposed that humans are genetically predisposed to have a theory of mind because there has been evolutionary selection for the human ability to adopt the intentional stance. The \"intentional stance\" is a useful behavioral strategy by which humans assume that others ha...
what is the deal with equifax breach to a non-american	Equifax is a credit reporting agency, meaning that they track the financial activity of Americans and provide information on their credit worthiness to banks and other institutions. If you want a loan, open a credit card, even get a new job in some cases, they will pull a report of your credit from one of the three cre...	[ "In September 2017, Equifax announced a cyber-security breach, which it claims to have occurred between mid-May and July 2017, where cybercriminals accessed approximately 145.5 million U.S. Equifax consumers' personal data, including their full names, Social Security numbers, birth dates, addresses, and driver lice...
why can i get my right leg almost over my head while my left leg i can barely get within a foot of it?	The simple answer is just that your right hip joint is more flexible than your left. Could be a combination of hyper-mobility (increased range of motion) in your right joint and/or ankylosis (decreased range of motion) in your left joint. Being more flexible in one joint but not the opposite it pretty common actually.	[ "When the pelvis descends on the unsupported side, the lower limb becomes, in effect, too long and does not clear the ground when the foot is brought forward in the swing phase of walking. To compensate, the individual leans away from the unsupported side, raising the pelvis to allow adequate room for the foot to c...
Is there a universal coordinate system for .. the universe?	There is no special frame of reference. There is a distinction between inertial and non-inertial frames.	[ "In astronomy, a celestial coordinate system (or celestial reference system) is a system for specifying positions of celestial objects: satellites, planets, stars, galaxies, and so on. Coordinate systems can specify an object's position in three-dimensional space or plot merely its direction on a celestial sphere, ...
if a gallon of gasoline weighs only 6 lbs, how does it produce 20 lbs of co2?	The gasoline supplies only the carbon (C), the oxygen (O2) comes from the atmosphere. Carbon weighs 12 grams per mole, oxygen weighs 16 grams per mole, so for every kilogram of carbon you need 2.67 kilograms of oxygen. The carbon content of gasoline depends on which molecules are in it; if we assume pure octane (C8H18)...	[ "In 1994, the US National Institute of Standards and Technology (NIST) defined \"gasoline gallon equivalent (GGE) means 5.660 pounds of natural gas.\" Compressed natural gas (CNG), for example, is a gas rather than a liquid. It can be measured by its volume in standard cubic feet (ft³) (volume at atmospheric condit...
Is a drug-resistant TB epidemic possible?	[Searched](_URL_7_) Relevant [discussion](_URL_3_) Original question by [TubeZ](_URL_4_) > With recent articles about Totally drug-resistant TB, is there reason to be concerned about it? Relevant comment courtesy [Teedy](_URL_0_) > TB spreads as airborne spore, and has well and truly been very nearly eradicated ...	[ "Primary resistance occurs when a person becomes infected with a resistant strain of TB. A person with fully susceptible MTB may develop secondary (acquired) resistance during therapy because of inadequate treatment, not taking the prescribed regimen appropriately (lack of compliance), or using low-quality medicati...
How is it possible that negative heat capacities exist, and what do they mean physically?	That sounds like a mistake or typo in your book. NIST, the main organization that keeps track of reference data values, [shows Pyrite](_URL_1_) as having a positive heat capacity for all reasonable temperatures. [Negative Temperature](_URL_0_) does exist, but it's mostly a weird quirk of our mathematical description o...	[ "Most physical systems exhibit a positive heat capacity. However, even though it can seem paradoxical at first, there are some systems for which the heat capacity is \"negative\". These are inhomogeneous systems that do not meet the strict definition of thermodynamic equilibrium. They include gravitating objects su...
is a sneezes volume/style hereditary, learned behavior, some other influences or are there no influences whatsoever?	Style is definitely learned. We attache some syllables to the act of sneezing that vary by geographic location. _URL_0_	[ "There is much debate about the true cause and mechanism of the sneezing fits brought about by the photic sneeze reflex. Sneezing occurs in response to irritation in the nasal cavity, which results in an afferent nerve fiber signal propagating through the ophthalmic and maxillary branches of the trigeminal nerve to...
Why did some Czechs had to leave Sudetenland and some could stay after Munich agreement?	Without knowing your family history or anything it could have just been your Austrian last name. It wasn't an exact science; so when the Bureaucrats went through the lists it could have been as simple as "Novák.. has to go. Müller... can stay" When actually Novak might have spoken primarily German, and Muller spoke C...	[ "The Czechoslovaks were dismayed with the Munich settlement. They were not invited to the conference, and felt they had been betrayed by the United Kingdom and France. Czechs and Slovaks call the Munich Agreement the Munich Diktat (; ). The phrase \"Munich Betrayal\" (; ) is also used because the military alliance ...
how did the internet grow to be the way it is today?	WARNING: What follows is a layman's understanding and may be totally wrong. I was only half paying attention during my IT lecture. The distinction between the WWW and the Internet is often missed, but is an important distinction to make. The World Wide Web is the thing we use day to day, but it is enabled by the int...	[ "In 1993, the release of the Mosaic web browser made access to the World Wide Web possible (prior Internet services like Usenet, Gopher, FTP, etc existed but HTTP was the new invention which triggered this growth). Internet use increased as a result of the reduction of the \"digital divide\" and advances in connect...
why does turning canned air upside down spray cold liquid?	At high pressure, gas can turn into a liquid, regardless of its temperature. Since liquid gas is a lot denser than normal gas, you can put more into the container. As a bonus, liquid gas tries to turn into normal gas if it's exposed to lower pressures (like normal air), so you can just put liquid gas in a can with a va...	[ "Canned air can be used for cleaning dust off surfaces such as keyboards, as well as sensitive electronics in which moisture is not desired. When using canned air, it is recommended to not hold the can upside down, as this can result in spraying liquid on to the surface. The liquid, when released from the can, boil...
Why have we not seemingly seen advances in audio technology to the extent we have seen advances in visual technology?	Precisely because sound is the air being vibrated. There's been advances in how the electronics and processing works, there's been advances int eh design of the cones, and how the drivers operate. But ultimately speakers are able to reproduce sound to a degree where it is nearly indistinguishable for the original r...	[ "Acceptance of innovative technologies can be improved by providing non-emotional and concise information about these new technological processes methods. The HighTech project also suggests that written information has a higher impact on consumers than audio-visual information.\n", "After the use of training film...
the rna world hypothesis	Currently: DNA- > RNA- > protein=functional enzymes DNA codes for proteins that are enzymes that do things in your body such as copying DNA. As it so happens, RNA can perform both functions: holding information and acting as an enzymes. The RNA world hypothesis is that RNA was the first biopolymer and performed both...	[ "The RNA world hypothesis is still under consideration, with chemist Steven A. Benner and physicist Paul Davies supporting it in a chapter of the book \"Frontiers of Astrobiology\" published in 2012 by the Cambridge University Press, in the chapter \"Towards a Theory of Life\"\n", "The RNA world hypothesis descri...
What is the earliest written record in Europe?	[The Minoan Culture had writing around 3000 BC.](_URL_0_)	[ "The tablets are the earliest written documents found in Britain, dating from 50 to 80 AD in the early Roman period. Notably, these tablets predate the Vindolanda tablets, which were previously the earliest writing examples found in Britain, dating to 100 AD or later.\n", "The oldest known document is the poem \"...
how would synthetic meat be better than normal meat environmentally?	[Yes](_URL_3_). [Immensely](_URL_1_). How, exactly? Well, let's take a cow. There's a lot of parts of a cow that aren't used for meat. The cow has to live for a few years, eat, grow, walk around, expel waste, all that jazz. That just eats up time and energy. In a lab, that time gets [cut down](_URL_0_) (5 oz in \~ 2 ...	[ "\"Artificial meat stops cruelty to animals, is better for the environment, could be safer and more efficient, and even healthier. We have a moral obligation to support this kind of research. It gets the ethical two thumbs up.\"\n", "In addition to the prevention and lack of diseases, and lack of the use of antib...
if coca-cola's recipe is a trade secret, what would happen if someone reverse-engineered it?	Exactly what happened when someone did - nothing. Coca-Cola is not about the flavor. It would not be difficult to replicate Coca-Cola - although one known ingredient, the coca leaf extract, flavors from the plant that cocaine comes from, isn't available to anyone else because of drug laws. Coca-Cola is about the brand...	[ "Sanders' Original Recipe of \"11 herbs and spices\" is one of the most famous trade secrets in the catering industry. The recipe is not patented, because patent law requires public disclosure of an invention and provides protection only for a strictly limited term, whereas trade secrets can remain the intellectual...
why don't some people react to pepper spray?	They have special eyes.	[ "Pepper spray is one non-lethal weapon alleged to have been misused by American police. In two incidents in California in 1997, police swabbed pepper spray directly into the eyes of protesters. Amnesty International condemned these actions, and claimed that they were likely a violation of the 1984 United Nations Co...
draining the swamp	a term used by Donald Trump during his campaign (not sure if he actually started it or his supporters did) as a catchphrase for his statement that he would get the big business influence out of washington. On that note, he's not wrong, there are a lot of people in the government who either are from or have ties t...	[ "With regard to tactics, the terms \"drain the water\" or \"drain the swamp\" involves the forced relocation of the population (\"water\") to expose the rebels or insurgents (\"fish\"). In other words, relocation deprives the aforementioned of the support, cover, and resources of the local population.\n", "While ...
why are movies still released in theaters?	Because going to the theater is an experience. You go with a group of people, you are watching a screen much larger than you could ever own with a sound system far superior to what you could ever own. Yes you can watch the movie online in your home, or buy it on Blueray or via your cable but you cannot replicate the mo...	[ "Theatrical [release] is over for about 90 per cent of any film made anywhere in the world. You just have to look at what's released in cinemas now to understand that, but we are still compelled and forced to release every Australian film that gets made to give it a theatrical release, because of the way things are...
Liquid nitrogen excessive boiling before critical temperature?	This is related to the transition between different modes of two-phase heat transfer. Initially, the temperature difference between the copper surface and the surrounding liquid is ~300 K, so a film of evaporated nitrogen gas envelops most of the block and insulates it thermally, making the rate of cooling slow. This...	[ "Liquid nitrogen is a cryogenic fluid that can cause rapid freezing on contact with living tissue. When appropriately insulated from ambient heat, liquid nitrogen can be stored and transported, for example in vacuum flasks. The temperature is held constant at 77 K by slow boiling of the liquid, resulting in the evo...
Why do some materials, like water, do a really good job of blocking nuclear radiation, but allow light to pass through practically unhindered?	So, first, there are several types of radiation you might get from a nuclear reaction. Alpha, beta and gamma radiation are helium nuclei, electrons, and high energy photons respectively. It is easier for heavier (larger, slower) radiation to interact with any solid or liquid matter you put in their path, so Alpha and ...	[ "Radiation can have harmful effects on solid materials as it can degrade their properties so that they are no longer mechanically sound. This is of special concern as it can greatly affect their ability to perform in nuclear reactors and is the emphasis of radiation material science, which seeks to mitigate this da...
where does energy 'go' when it is used by a living thing?	When you eat, you absorb the carbs, proteins etc. When you run, these are broken down in order to give you energy to run. That energy was spent in moving your body from one place to another - it gets transformed into kinetic energy and potential energy and also produces body heat. In a nutshell as you have learnt energ...	[ "In physics, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object. Energy is a conserved quantity; the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The SI unit of energy is the joule,...
the byzantine generals problem.	The Byzantine Generals Problem is a model for communication. It uses some number of players ("Generals") who have to come to a consensus. However, they are limited in how they are allowed to communicate--they have to send messages by courier, but the couriers may get captured (i.e. they never deliver their message). ...	[ "The same authors helped to popularize the interactive consistency problem in their 1982 paper, \"The Byzantine Generals Problem\", which presents it in the form of a colorful allegory proposed by Lamport. In the allegory, the computers are replaced by Byzantine generals who needed to coordinate the timing of an at...
What would happen if the poles switched?	If by every couple of years you mean every couple of tens of thousands to millions of years, then yes, the [polarity of the earth's magnetic field definitely flips occasionally](_URL_0_). The image on that page shows the geomagnetic timescale with black bars indicating 'normal' polarity (the orientation of the field no...	[ "Owing to motion of fluid in the Earth's outer core, the actual magnetic poles are constantly moving. However, over thousands of years their direction averages to the Earth's rotation axis. On the order of once every half a million years, the poles reverse (north switches place with south).\n", "The precise locat...
Did the Knights Templar really commit heresy in their initiation rites?	There are three broad theories about the confessions of certain Templars obtained by ~~Louis~~ Philip IV: 1. The confessions were extracted by putting words into the mouths of the leaders of the tortured, or confessions were otherwise falsely recorded. 2. The basis of some confessions were found in actual acts but ma...	[ "The original Knights Templar, founded around 1119, had been a crusading military order, that, at some time, had established financial networks across the whole of Christendom. In 1307, King Philip IV of France mounted a \"slanderous campaign\" to strip the Order of its economic and political influence. The Templar...
In the sixteenth century, how did understanding of the Protestant Reformation evolve among Catholic leaders? Did they go from seeing it as a temporary split, over time, to a more permanent schism?	Oh man, you’re gonna love [this](_URL_0_) post by u/sunagainstgold. He talks about what made Martin Luther so special an what exactly people at the time were expecting to happen.	[ "The Reformation swept through Europe during the 16th century. The excommunication of Protestants by leaders of the Roman Catholic Church ended centuries of unity among Western Christendom. The religion of an heir to the throne became an intensely important political issue. The refusal of Pope Clement VI to grant a...
How accurate is this representation of Viking combat?	Could you post the video?	[ "The battle is included in the 's expansion 'Viking Conquest'. The battle might take place before its historical date though, depending on player's choices. During the battle, the player character will clash against the Dane invaders aided by the West Seaxe army, and take revenge on Sven Bull Neck, a fictional Viki...
How much does Eric William's Capitalism and Slavery (1944) hold up?	(1/2) The short, and profoundly unhelpful answer, is that it depends entirely on who you ask and what you mean by "hold up", and for what reasons you're interested in Williams' ideas. The ideas presented in Capitalism and Slavery are today referred to simply as 'the Williams thesis' by scholars of transatlantic slav...	[ "In the same body of evidence, he notes that the fatality rate for his slaves was one in twelve, and that \"The average allowance of width to a slave is fourteen and two-thirds inches.\" Penny also argued that abolition of the trade would destroy the economy of Liverpool; \"it would not only greatly affect the comm...
How can scientists accurately measure the populations of insects?	Look up malaise flight traps and pitfall traps. These are two common methods for collecting insects and the data gathered by them can be used to explore the incidence and abundance of the species. I use pitfall traps to estimate the abundance of native ant species in communities that are undergoing invasion by the in...	[ "Researching the collections of insects provides important information that develops knowledge about ecology, human health and crops. Well-kept records aid the researcher in identifying whether there are differences in an observed specimen because of damages, treatments or deterioration. Research of the insect coll...
How is graphite formed?	Anthracite coal is mainly amorphous (glassy) carbon, but the properties of graphite aren't due to its purity as much as its molecular structure. Amorphous carbon is full of carbon atoms making 4 bonds any which way they can, but graphite has the atoms arranged into sheets made up of a hexagonal arrangement of carbon a...	[ "Graphite (), archaically referred to as plumbago, is a crystalline form of the element carbon with its atoms arranged in a hexagonal structure. It occurs naturally in this form and is the most stable form of carbon under standard conditions. Under high pressures and temperatures it converts to diamond. Graphite is...
what happens to the proceeds of crime?	The police get to keep it. It's called "civil asset forfeiture", and it gets rolled into the police budget. It's been a big sticking point lately because it has been used to seize money that almost certainly was not acquired or intended to be used illegally.	[ "The Proceeds of Crime Act 2002 (c.29) (POCA) is an Act of the Parliament of the United Kingdom which provides for the confiscation or civil recovery of the proceeds from crime and contains the principal money laundering legislation in the UK.\n", "BULLET::::- Killing out of greed means that the perpetrator kills...
Has the speed of the increase in computer processing speed slowed way down?	It's true that clock speeds aren't increasing like they used to, but there's more to processor speed than clock rate. So the question is a little complicated. First, what is clock speed? A processor is made up of a lot of transistors, which in digital circuits (like a CPU), work like tiny switches. These switches...	[ "CPU speed improvements slowed significantly partly due to major physical barriers and partly because current CPU designs have already hit the memory wall in some sense. Intel summarized these causes in a 2005 document.\n", "Overall productivity growth was relatively slow from the 1970s through the early 1990s. A...
how is that alcohol is not good for flesh wounds?	First, alcohol is a blood thinner and can lead to excessive bleeding from wounds. Second, it is a disinfectant but it's rarely ever drank by itself and the sugars feed bacteria that can get into the open wound. It also works by drying out bacteria and your cells essentially killing them making wound repair with long t...	[ "BULLET::::- Alcohol – Alcohol consumption impairs wound healing and also increases the chances of infection. Alcohol affects the proliferative phase of healing. A single unit of alcohol causes a negative effect on re-epithelialization, wound closure, collagen production and angiogenesis.\n", "Alcohols, in variou...
if all 7.4 billion humans were to drop dead right now, how many fossilized skeletons would we leave in 65 million years, and what evidence of our civilization would there be?	I can't answer the first part, but there are a few Shows you can watch they did this topic. [Aftermath: Population Zero](_URL_1_) was on the National Geographic channel. They did an overall View of the planet. Their final statement: > (25,000 years A.H) Earth enters a new Ice Age, and glaciers expand south coveri...	[ "Should the human race become extinct, then the various features assembled by humanity will begin to decay. The largest structures have an estimated decay half-life of about 1,000 years. The last surviving structures would most likely be open pit mines, large landfills, major highways, wide canal cuts, and earth-fi...
how are engineers able to build subway tunnels under already built infrastructure?	There are multiple ways that they can do it. Here in Boston where I live they finished the [Big Dig](_URL_1_) a few years ago. Over the course of roughly ten years they consolidated all the utilities through a corridor of the city and then sank an entire elevated highway underground. It had to go above and below var...	[ "Other challenges included existing subway tunnels crossing the path of the underground highway. To build slurry walls past these tunnels, it was necessary to dig beneath the tunnels and to build an underground concrete bridge to support the tunnels' weight, without interrupting rail service.\n", "Underground tun...
why are graves 6ft deep?	That was found to be the depth necessary to prevent animals from picking up the scent and digging for food.	[ "The depth of the graves varied, although most were around 0.36 metres deep below the 1950s soil level. The deepest was below, while the shallowest were below the modern surface, indicating that the Anglo-Saxon ground level was undoubtedly higher. The sizes of the graves also varied, with the smallest being , and t...
Pretend I'm a fish and get swallowed whole by a shark... How long do I live inside the shark/what ultimately kills me?	> Most sharks swallow their food whole or bite it into relatively large pieces. Sharks have U-shaped stomachs that use very strong acids and enzymes to dissolve most of what is eaten. Doesn't sound like a very long time. Source: _URL_0_	[ "Digestion can take a long time. The food moves from the mouth to a J-shaped stomach, where it is stored and initial digestion occurs. Unwanted items may never get past the stomach, and instead the shark either vomits or turns its stomachs inside out and ejects unwanted items from its mouth.\n", "The shark chases...
Does an equation exist which is used to calculate the melting temperature of compounds?	IIRC You can calculate the boiling point of a compound via the Clausius-Clapeyron relation, so long as you know the latent heat of vaporization. (_URL_0_) From my humble opinion (~6 years of physics) I would say classical thermodynamics is a very empirical field (trying to match experiments, find working relations, mi...	[ "The previous paragraph shows how melting temperature and thermodynamic parameters (Δ\"G\"° or Δ\"H\"° & Δ\"S\"°) are related to each other. From the observation of melting temperatures one can experimentally determine the thermodynamic parameters. Vice versa, and important for applications, when the thermodynamic ...
Is there a reason that truck trailers transporting liquids have a cone shape at the back of the container?	You'll probably need to clarify to get the answer you're looking for. Can you provide a picture of what you're talking about? Most [tanker trucks](_URL_0_) are round or elliptical in cross-section, and they usually have a flat or domed rear closeout. The shape is dictated by the pressure of the fluid inside, but gen...	[ "BULLET::::- Container trailers are standard intermodal \"boxes\" that can be fitted with a dolly (wheel truck) and front stand; they can then be used in a standard tractor-trailer combination. The containers are also stacked on ships and used as railroad boxcars.\n", "The second aggregate container on the traile...
why do cops put white towels on the shoulders of saved victims in crimes scenes on the movies?	I don't know about white towels, but ambulances have foil heat blankets that are used to treat hypothermia and are also used for shock. One of the symptoms of shock is cold, clammy skin, so presumably these blankets, which can trap body heat, help with that.	[ "Since the Terrible Towel's debut, teams have used similar gimmicks, mainly using white towels (or towels with the team's colors) and giving them out to fans. The main time teams give rally towels is during league postseasons. Towels have gained much popularity as distractions to visiting players. Teams that use ra...
how do big development teams such as bethesda work on huge games like elder scrolls and fallout for multiple years without a single leak from within the huge dev team?	The threat of being sued into oblivion (no pun intended) for violating a non disclosure agreement, losing your job, and being known as untrustworthy in the industry is enough for most people. Game development is often pretty compartmentalized so it wouldn't be too hard to track down people behind the leaks since only c...	[ "Since its foundation, Bethesda Game Studios has principally been involved in the development of role-playing video games with their \"The Elder Scrolls\" and \"Fallout\" series for consoles and personal computers, almost all of which have been commercially and financially successful.\n", "The Elder Scrolls Renew...
has all the nuclear radiation emitted since 1945 affected human genetics at all?	We're exposed to far more natural radiation than to radiation from nuclear weapons, at least on average. The reason is that there are radioactive substances in the ground, and that there is radiation coming from space. [Here](_URL_0_) is a useful infrographic that shows pretty well how much radiation we receive from w...	[ "The genetic effects of radiation, including the effects on cancer risk, were recognized much later. In 1927 Hermann Joseph Muller published research showing genetic effects, and in 1946 was awarded the Nobel prize for his findings. Radiation was soon linked to bone cancer in the radium dial painters, but this was ...
Why do you get an immediate jolt to your heart rate when you think you're in danger? What purpose does this serve?	The Sympathetic Nervous System (SNS) is responsible for the "fight or flight" response you describe. SNS innervation to the heart increases heart rate and the amount of blood pumped to the body. It also increases your alertness, releases chemicals like adrenaline, diverts blood to vital organs and muscles, and genera...	[ "The symptoms of a panic attack may cause the person to feel that their body is failing. The symptoms can be understood as follows. First, there is frequently the sudden onset of fear with little provoking stimulus. This leads to a release of adrenaline (epinephrine) which brings about the fight-or-flight response ...
how do you "create" internet?	Well, you seem to be talking about two different components of "internet." The actual content you access is nothing more than data on a computer somewhere. Let's say I create a text file on my computer and call it "Information.txt." Then, you use some software on your computer to access that information, maybe by typi...	[ "A web project is the process of developing and creating a Web site, activities in a network which are aimed at a pre-defined goal. The network can be both accessible for everyone, as in the Internet, or only for certain people, as an intranet. The goal of Web projects is the transfer of static and dynamic content ...
why do sone christians consider any kind of electronic implant the "mark of the beast" and what exactly is the mark of beast from a literal standpoint?	I think that the question: * What exactly is "xxx" in a prophecy, from a literal stand point is the wrong question. The nature of prophecy is non-literal. It is like reading an IKEA manual and looking for prophetic symbolism.	[ "In the 2008 book \"Vintage Jesus: Timeless Answers to Timely Questions\", authors Mark Driscoll and Gerry Breshears write: \"According to Scientology, Jesus is an 'implant' forced upon a thetan about a million years ago\". In \"A Piece of Blue Sky\", Jon Atack writes \"In confidential issues, Hubbard dismissed Chr...
To what extent did the Arabs influence the Spanish language, art, and literature?	I can only comment on architecture, but I studied in Toledo, Spain for 4 months and took a class on the art and architecture of the city. It's known as the "City of the Three Cultures" due to the Christian, Arab, and Jewish influence on life/art/culture. Muslims were not all expelled when the city was reconquered, and ...	[ "During the Middle Ages, Literary Arabic was a major vehicle of culture in Europe, especially in science, mathematics and philosophy. As a result, many European languages have also borrowed many words from it. Arabic influence, mainly in vocabulary, is seen in European languages, mainly Spanish and to a lesser exte...
aleph numbers....whaaat?	In short, there are different values of infinity, and some are larger than others. Very crazy, but there it is. Here are examples of infinities: (A) the number of whole numbers, (B), the number of even whole numbers, (C) the number of fractions, and (D) the number of all possible numbers (including numbers like sqrt(...	[ "In mathematics, and in particular set theory, the aleph numbers are a sequence of numbers used to represent the cardinality (or size) of infinite sets that can be well-ordered. They are named after the symbol used to denote them, the Hebrew letter aleph (formula_1) (though in older mathematics books the letter ale...
zen buddhism	Because you're reading a Rinzai Zen scholar (DT Suzuki) and a Soto Zen monk (Dogen). Two sects, two schools. Zen is a sect of Buddhism that is Mind to Mind transmission outside the Scriptures. This doesn't mean it doesn't use scriptures. It only means it's not founded on them. When Buddha twirled a flower and Mahak...	[ "The term Zen is derived from the Japanese pronunciation of the Middle Chinese word 禪 (\"Chán\"), which traces its roots to the Indian practice of \"dhyāna\" (\"meditation\"). Zen emphasizes rigorous self-control, meditation-practice, insight into the nature of things (Ch. \"jianxing,\" Jp. \"kensho,\" \"perceiving...
When someone suffers from depression, why are memories from that time hard to recollect?	Our mind has a coping mechanism that erases memories which are too painful for us to bear. It's a very simple answer and I'm sure there is more to it than that, but it's certainly one of the reasons it is hard to recall memories from that time.	[ "Some memory issues are due to stress, anxiety, or depression. A traumatic life event, such as the death of a spouse, can lead to changes in lifestyle and can leave an elderly person feeling unsure of themselves, sad, and lonely. Dealing with such drastic life changes can therefore leave some people confused or for...
Why did China recover from the collapse of the Han Dynasty so much better than the Mediterranean recovered from the collapse of the Roman Empire?	Well, you are whitewashing tons of complexity over a massive period of time (200 CE - 1800 CE), but in general the basics are there in your subtext. Rice cultivation was a major part of the story, as it was key to the success of the southern states after the fall of the Han. The Cao family's wei dynasty could not ful...	[ "The Han defeated and drove the Xiongnus west, securing the city-states along the silk route that continued into the Parthian Empire. After the decline of central imperial authority, the Han Dynasty collapsed into an era of civil war and continuous warfare during the Three Kingdoms period in the 3rd century AD.\n",...
why do pictures of the stars from telescopes along with photos of most light sources appear to have horizontal and vertical lines through them resembling crosshairs?	The lines are called "diffraction spikes", and they are caused by light waves being interfered with by the structure or shape of the camera or telescope. The most common one in star photographs is four spikes. Many star photos are taken with a reflector telescope, which has a mirror mounted inside it - usually on fou...	[ "Star trail photographs are possible because of the rotation of Earth about its axis. The apparent motion of the stars is recorded as mostly curved streaks on the film or detector. For observers in the Northern Hemisphere, aiming the camera northward creates an image with concentric circular arcs centered on the no...
if the water cycle is a closed system, why does it matter that a pound of beef takes 1800 gallons of water to produce?	It's a matter of clean/potable water. The water used to produce beef must be potable, and ends up non-potable, so that puts an enormous strain on the availability of clean water in an area. Yes, it does go back into the water cycle, but it takes a long while for it to make its way back to a drinkable state.	[ "Livestock and meat production have one of the largest water footprints of the agricultural industry. Taking nearly 1,800 gallons of water to produce one pound of beef and 576 gallons for pork. For reference, it only takes about 108 gallons of water to harvest one pound of corn. Livestock production is also one of ...
why do you have to turn most jeans and some other clothing inside-out when washing them...?	You're supposed to turn clothes inside out?? I always thought it was the opposite, since it's the outside getting dirty (except for maybe underwear).	[ "t is often a requirement of \"home made\" garments (adhesive based transfers) that they be washed inside out, only in cold water, sometimes by hand, and not be tumble dried. The heat from washing or drying conventionally, or from ironing over the transfer area, can damage the transfer or cause it to separate. Thes...
Mitochondria living outside of cells?	> are there still independent mitochondria somewhere on Earth Not literally, because mitochondrial DNA is vestigial compared with their original ancestors. Mitochondria have only a few dozen genes, and have lost all the ones necessary for independent functioning. So then, in the same spirit, are there independent d...	[ "Mitochondria are the \"power house\" of biological cells. It is thought that they were originally separate organisms, and a symbiotic relationship between them and early cellular life has evolved into their present position as cell organelles with no independent existence (see endosymbiotic theory).\n", "Mitocho...
Could dangerous radiation from depleted nuclear reactor cores be harvested?	For the broader question, we do: they're called [Radioisotope Thermoelectric Generators](_URL_0_). Basically, your intuition is correct: the heat produced by radioactive decay, when run through a thermocouple, generates electricity, making a sort of nuclear battery. Here's the thing: the strength of RTGs is that they...	[ "Since the radiation levels are still very high at the inside of the reactor core, it is not likely anyone can go inside to assess the damage. The Fukushima Daiichi Tracker (FDT) is proposed to see the extent of the damage from a safe distance. A few months of measurements with muon tomography, will show the distri...
could someone please explain to me "bell's non-locality theorem"?	There is no way a five year old can understand the Bell Theorem; sorry. I can still try to explain it, but not necessarily on ELI5 level. In quantum mechanics, things are a bit different than in the macroscopic world. For one, QM processes are not deterministic, but probabilistic. That means, that it is not possi...	[ "In mathematics, circle-valued Morse theory studies the topology of a smooth manifold by analyzing the critical points of smooth maps from the manifold to the circle, in the framework of Morse homology. It is an important special case of Sergei Novikov's Morse theory of closed one-forms.\n", "The problem that Mor...

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