Split (2)

train · 226k rows

question stringlengths 3 301	answer stringlengths 9 26.1k	context list
If every human being in the world were to sit on a bike machine and pedal, will it generate a significant amount of electricity?	On average, people have a power of about 100 Watts (~2000 Calories per day). 7 billion of them makes 700 gigwatts, about 1/20th of the world's average power consumption. However, for short periods of time people can produce more power (only elite cyclists can produce 20 times as much though).	[ "Human power is a simple source of energy that requires nothing more than humans. Despite the fact that humans cannot exceed for meaningful amounts of time, the land speed record for human-powered vehicles (unpaced) is , as of 2009 on a recumbent bicycle.\n", "World records of power performance by humans are of i...
why isn't 'being a qualified scientist' one of the requirements for a job as chairman of the committee of science and space (example: ted cruz)?	Because there aren't enough scientists/doctors/teachers in Congress to make that workable.	[ "The Chief Scientist is the most senior science position at the National Aeronautics and Space Administration (NASA). The Chief Scientist serves as the principal advisor to the NASA Administrator in science issues and as interface to the national and international science community, ensuring that NASA research prog...
When consuming alcoholic drinks, how does our body know we've had too much, and makes us vomit?	Alcohol gets metabolized into acetaldehyde in the liver and sometimes the brain also. When there is enough acetaldehyde built up in your peripheral nervous system, a purge/vomit response is initiated to deal with the toxicity.	[ "Vomiting excessive amounts of alcohol is an attempt by the body to prevent alcohol poisoning and death. Vomiting may also be caused by other drugs, such as opiates, or toxins found in some foods and plants. Food allergies and sensitivities, such as lactose intolerance, can cause vomiting.\n", "Alcohol is absorbe...
why does ibm watson have so many commercials? (who is the target?)	It is mostly about branding *getting their name out there repeatedly over and over - so when you think of the best possible soda - Coke or Pepsi pops in your head. When you think of fast food - boom you think of mcdonalds or burger king When you think of getting an alternative taxi via cell phone - you think of ube...	[ "The company built a successful business based upon significant advertising, leading to sales of over $100M per year. The product, along with its catchphrase \"Hooked on Phonics worked for me!\" (spoken by children in the product's television ads) and its telephone number \"1-800-ABCDEFG\" (now belonging to the Wil...
Why can chimerism exist, while donor organs seem to get rejected?	During fetal development a process known as "immune tolerance" takes place where B and T cells that react against the body's own tissues are eliminated. Since the chimeric part of the body is present during fetal development, the immune system will learn to treat it as self. See: _URL_0_ Transplants, which are added a...	[ "A proposed strategy to avoid cellular rejection is to induce donor non-responsiveness using hematopoietic chimerism. Donor stem cells are introduced into the bone marrow of the recipient, where they coexist with the recipient’s stem cells. The bone marrow stem cells give rise to cells of all hematopoietic lineages...
Why bones in X-ray images are white but not black?	X rays turn photographic film black. There is no inversion, what you see is what the Xrays do. It is easier to spot abnormalities with white on black. The early xrays would have affected the film in the same way, however the chemicals used , silver nitrate, would turn black on further exposure to light. To look at...	[ "X-rays (electromagnetic radiation) are projected through the body to produce an image of its internal structures. The radiation is more attenuated (absorbed) by the denser tissues of the body (i.e. bone) than the softer tissues (i.e. muscles, organs, etc) creating a picture composed of shades of grey ranging from ...
How come the Middle East and East Asia had eunuchs in the Imperial household, harems of women, and sedan chairs for getting around, but Europe generally didn't?	Christianity didn't allow polygamy, while in Islam and China it was accepted. Concubines are allowed in Islam, although men can have only 4 legitimate wives.	[ "Eunuchs are castrated men who have often been used as servants in imperial and noble households, due to the belief that they would not be distracted by or a danger to women. Eunuchs were often utilized in the imperial household as harem guards and attendants. The harems were considered necessary in order to help p...
how do nighttime rainbows function?	A moonbow (also known as a lunar rainbow or white rainbow), is a rainbow produced by moonlight rather than sunlight. Other than the difference in light source, its formation is exactly the same as for a solar rainbow: It is caused by the refraction of light in many water droplets, such as a rain shower or a waterfall, ...	[ "The rainbow effect is also commonly seen near waterfalls or fountains. In addition, the effect can be artificially created by dispersing water droplets into the air during a sunny day. Rarely, a moonbow, lunar rainbow or nighttime rainbow, can be seen on strongly moonlit nights. As human visual perception for colo...
what is the science behind cryogenically freezing someone? is there any real hope that a cryogenically frozen person will be revived?	A follow up question, who takes care of the bodies while they're frozen? I'd imagine they cannot thaw, so they need constant supervision. Edit 1: TIL, [Cryonics and cryogenics aren't the same thing!](_URL_0_) "... cryogenics, which deals with extremely low temperatures, has no connection with cryonics, the belief tha...	[ "Cryonics procedures can begin only after clinical death, and cryonics \"patients\" are legally dead. Cryonics procedures ideally begin within minutes of death, and use cryoprotectants to prevent ice formation during cryopreservation. It is however not possible for a corpse to be reanimated after undergoing vitrifi...
eili5: solipsism	I know I exist, but I'm not sure about you. "Know" used in the most literal and strict sense possible.	[ "The foundations of solipsism are in turn the foundations of the view that the individual's understanding of any and all psychological concepts (thinking, willing, perceiving, etc.) is accomplished by making an analogy with his or her own mental states; \"i.e.\", by abstraction from \"inner experience\". And this v...
How long would it have on average taken for a 1 km stretch of road to be built in the Roman Empire?	Follow up question: I'd read something about (but can't find good sources) on when wheelbarrows started being used. Did the Romans use them (as the leftmost person depicted in the picture)?	[ "Now all you needed to do was say a days journey was 24 hours x 60 minutes x 60 seconds. A century was 100 years of 365.34 days journey. The number of seconds was twice the distance in inches. The circumference of the earth was 24902.72727 miles making a degree 4382880\" or 365,240 feet. A days march by the Roman r...
Is It Possible That The Big Crunch Has Already Begun?	No. We can measure that it is still expanding (at least as recently as a few million years ago).	[ "The Big Crunch is a theoretical scenario for the ultimate fate of the universe, in which the expansion of the universe eventually reverses and the universe recollapses, ultimately causing the cosmic scale factor to reach zero, an event potentially followed by a reformation of the universe starting with another Big...
why do investors value higher margins over higher overall profits?	It's about competitive advantage. To get high margins, you have to have a competitive advantage, otherwise competitors scoop in and pricing and margins decline. The higher your margins, the stronger the competitive advantage. It could be anything (brands, skill of management, IP, barriers to entry, innovative produc...	[ "Profit margin is an indicator of a company's pricing strategies and how well it controls costs. Differences in competitive strategy and product mix cause the profit margin to vary among different companies.\n", "The profit margin is used mostly for internal comparison. It is difficult to accurately compare the n...
In which post-1945 wars did US troops end up doing good* going into another country?	This seems like a really charged answer, and your criteria of good is very odd. The Korean War could be seen as "good" war under those criteria. The US was not defeated, it achieved its goal of preserving the South, China and the USSR were already our enemies (that whole Communism thing) and the region had no stabili...	[ "With the end of World War I in November 1918, Camp Mills then performed a mission to process the thousands of troops back into the United States as a demobilization center. Many returning units passed through it and were either demobilized or sent to other camps across the United States where the men were processe...
How is the rapid vanishing of languages across the globe affecting the field of linguistics?	Linguistics is a wide-ranging discipline. For some areas of study, losing languages isn't all that relevant; for others, it's critical. Fields like dialectology and typology (the study of what kind of languages are there, what features are common, which co-occur etc.) are obviously very concerned about it; linguistic...	[ "The preservation of cultural and linguistic diversity in today's world is a major concern to many scientists, artists, writers, politicians, leaders of linguistic communities, and defenders of linguistic human rights. More than half of the 6000 languages currently spoken in the world are estimated to be in danger ...
What are some examples of Roman/Han cultural diffusion through the Silk Road?	Well, there wasn't a lot of genuine cultural diffusion between the Roman Empire and the Han Chinese. It would take another few centuries for what we know as the Silk Road to really get cooking. But there was some, and here's [an entire Wikipedia article](_URL_1_) about it, and another article about [Chinese knowledge o...	[ "The ancient Northern Silk Road passes through Yongchang County; numerous Han envoys were sent west along this trackway, some parties exceeding 100 members, late in the first millennium BC. The Han dynasty sent one mission to Parthia, which was reciprocated around 100 BC: Roman emissaries were captured by the Chine...
why are card games and slot machines at casinos considered gambling and have an age limit, yet arcade coin machines aimed at children are not?	Usually those are technically, and by that I mean legally, "games of skill" since when/where you drop the coin effects the output. Slot machines are random and do not care if you pull the level or push the button, drop in one coin at a time or hit "Play Max", etc.	[ "There are many different kinds of gambling slot machines in places such as Las Vegas (as well as casinos modeled after those in Las Vegas, including those operated on Native American reservations). Some of the most popular are the video poker machines, in which players hope to obtain a set of symbols corresponding...
What is the problem with breathable liquid oxygen like Perfluorohexane?	I do remember the post you speak of, but I couldn't locate it. If I remember correctly, It wasn't because of the H or N removal, it was purely because that breathing a liquid still isn't manageable for humans. Presently, we don't have a compound which can provide enough oxygen while still being easy on our lungs - liqu...	[ "Because it is biologically inert and chemically stable, perfluorohexane has attracted attention in medicine. Like other fluorocarbons, perfluorohexane dissolves gases, including oxygen from the air, to a higher concentration than ordinary organic solvents. This effect is attributed to the weak intermolecular force...
how does the voyager keep leaving the solar system?	There's more than one definition of the edge of the solar system. There isn't a simple line in the sand (or in space) that separates our solar system from the rest of the universe. There's a fuzzy boundary, and it takes time to cross that boundary.	[ "In 2013, \"Voyager 1\" was escaping the Solar System at a speed of about 3.6 AU per year, while \"Voyager 2\" was only escaping at 3.3 AU per year. (Each year \"Voyager 1\" increases its lead over \"Voyager 2\")\n", "In 2013 \"Voyager 1\" was exiting the Solar System at a speed of about 3.6 AU per year, while \"...
Can you absorb nutrients through the colon?	The short answer is, yes! To some degree you can absorb substances through the rectum, which is why many medicines are made with suppository formulations. Some things such as alcohol and water can also be absorbed. Anything that is absorbed into your body and metabolized, regardless of the route of ingestion, could pro...	[ "Nutrients can be injected through all SSTI systems (fertigation). Macro and micro nutrients can be delivered to specific crops including grass, pasture, trees and vines. The nutrient is placed directly in the root zone so there is almost no wastage and no potential for run off into waterways.\n", "The colon is t...
how are bots able to get around captchas and security features on ticketmaster to buy thousands of tickets to concerts at a time?	Just to be very clear-- we have no idea how many (if any) tickets are purchased by bots on ticketmaster. In fact the article embedded in this states so, as below > Live Nation will not say how many of the 148 million tickets it sells each year are bought using bots, and in many cases it may not know But basically, i...	[ "A ticket bot is a software program that automates the process of searching for and buying tickets to events on ticket vendor platforms, such as Ticketmaster. Using bots, a broker can automate the process of searching for and buying tickets so that it happens in a flash, and conduct hundreds or even thousands of tr...
how are oranges specifically grown to be "easy peelers". or is it just simply a variety of orange.	Selective breeding. People plant the seeds of the ones that are easy to peel and don't plant the seeds of the ones that aren't. You can do this to get almost any quality if you give it enough time.	[ "The oranges then go through roller conveyors, which expose all sides of the fruit. The roller conveyors are efficiently built as they are well lighted, installed at a convenient height, and width to ensure all inspectors can reach the fruit to determine inadequacies. Some reasons why fruit may be rejected include ...
Regarding rats and clinical trials.	This has been an [ongoing issue](_URL_0_), especially when it comes to inflammatory diseases. While these rodent models work well for many things, there are differences! We study different [model organisms](_URL_2_) depending on how suited each one is to answering a particular question. Unfortunately, no model organ...	[ "Laboratory rats have also proved valuable in psychological studies of learning and other mental processes (Barnett 2002), as well as to understand group behavior and overcrowding (with the work of John B. Calhoun on behavioral sink). A 2007 study found rats to possess metacognition, a mental ability previously onl...
In the Tudor/Stuart periods, how did meals work at court.	I am glad you asked this question. I was recently reading [a collection of articles](_URL_1_) that extensively covers this for the Stuarts. The first point I'll make is that the Court changes drastically and continually as different monarchs and officials attempt reforms. Reforms to the provisioning of food for reta...	[ "Reflecting the typical custom of the 17th century, Louis XIV dined at noon, with a supper at 10pm. But in Europe, dinner began to move later in the day during the 1700s, due to developments in work practices, lighting, financial status, and cultural changes. The fashionable hour for dinner continued to be incremen...
kids medicine is dosed by weight but all adult medication is essentially take 2 pills.	That's not even remotely close to true, though. You've just happened to have been given drugs at a dosage that requires you to "take two however often". A lot of common antibiotics for example have a wide safe dosage range. Additionally, children are still developing and are more sensitive to a lot of things.	[ "The procedure is to take the child's weight in pounds, divide by 150 lb, and multiply the fractional result by the adult dose to find the equivalent child dosage. For example, if an adult dose of medication calls for 30 mg and the child weighs 30 lb, divide the weight by 150 (30/150) to obtain 1/5 and multiply 1/...
When did it become generally accepted that the speed of light is constant?	The Michelson-Morley experiment showed that it's always the same no matter how you're moving with respect to space. It also falls out of Maxwell's equations, that the speed of light is only dependent on the electric and magnetic properties of the vacuum and not a frame of reference.	[ "The speed of light was not yet precisely known in 1838; its value changed in 1849 (Fizeau) and 1862 (Foucault). It was not yet considered to be a fundamental constant of nature, and the propagation of light through the aether or space was still enigmatic.\n", "Before Ole Rømer made the first successful estimate ...
What was the most used weapons by Knights, and how expensive were the weapons?	That's a really in depth question. Knights were around for a very long time, the types of weapons used by and against them changed and varied drastically over this time. They would have started out with swords of varying sizes/styles but as plate armour improved swords became less effective so [war hammers](_URL_1_)) b...	[ "By the end of the 15th century, knights were becoming obsolete as countries started creating their own professional armies that were quicker to train, cheaper and easier to mobilize. The advancement of high-powered firearms eradicated the use of plate armour, as the time it took to train soldiers with guns was muc...
At the current rate human population is growing, how long until we can no longer live comfortably?	In my opinion, over population is the root of all our problems today.	[ "Following the present rate of birth, it is generally estimated that the world population will grow until it \"peaks\" in the middle of the present century, and then possibly begin to decline. How many people will be alive at this peak are estimated at between 8 billion and 20 billion people, depending upon what fa...
does listening to things in your sleep actually work?	Sadly, many studies have [discredited any claim](_URL_1_) that we learn facts and information while asleep. Although, we are apparently capable of [being conditioned](_URL_0_) while asleep.	[ "Sleep-learning (also known as hypnopædia, or hypnopedia) is an attempt to convey information to a sleeping person, typically by playing a sound recording to them while they sleep. Although often used in pop culture as a way to introduce new information (see 'In Fiction'), sleep is considered an important period fo...
the creation of aquarium glass. zoo's have huge pieces of glass containing the tank. how is this glass created and installed?	It isn't glass. It is plexiglass, which is stronger despite being less dense (heavy) as well as much easier to manipulate/form. Still, it can be as thick as half a meter or more (~1.5feet) in a large public aquarium. More info: > Polymethylmethacrylate (PMMA) is used. This is also known simply as acrylic or by its va...	[ "The largest aquarium is called \"Fosse Aux Requins\" which houses sharks and rays. It contains a false shipwreck in polyurethane resin (the iron would have rusted and the rust is toxic to fishes). Its glass is 23 centimetres thick to resist the water pressure.\n", "The tanks used in the aquarium are made of of a...
I'm interested in learning more about the opium wars, could you reccomend any literature on the subject? Is there any latent bias i should be aware of when looking at it considering the Anglo perspective im coming at it from?	You've just asked this question at a very opportune moment – Stephen R. Platt, author of Autumn in the Heavenly Kingdom (2012), has recently written Imperial Twilight: The Opium War and the End of China’s Last Golden Age, which will become available later this month. I've yet to read any serious academic reviews in...	[ "Lovell's book \"The Opium Wars: Drugs, Dreams and the Making of China\" was widely reviewed in both scholarly journals and the press. Matthew W. Mosca, writing in the \"Journal of Asian Studies\", wrote that the Opium War had \"once ranked among the most studied events in Chinese history,\" but interest had notabl...
How are lethal dosages calculated?	They test the substance on animals (frequently rats and mice) to determine the LD50 for those animals. Since the substances are usually administered at specific weights, they can find a ratio of weight of drug:weight of animal that, theoretically, would extrapolate to humans. However, it is an estimation and animal phy...	[ "The median lethal dose, LD (abbreviation for \"lethal dose, 50%\"), LC (lethal concentration, 50%) or LCt (lethal concentration and time) of a toxin, radiation, or pathogen is the dose required to kill half the members of a tested population after a specified test duration. LD figures are frequently used as a gene...
In Jesus Christ Superstar Judas scolds Mary Magdalene, saying that her "jar of fine ointment" could have been sold for 300 silver pieces or more. Judas later gets 30 for selling out Jesus. Do those numbers make sense in reality?	Depends on the size of the jar and the ointment inside ;) Often times, when in doubt about the price points for things, I like to refer back to this [handy dandy chart of Pliny's prices for Eastern goods](_URL_0_). Looking at those prices, you'll quickly notice that, for people who could actually afford a decent amount...	[ "Jesus goes to where they make offerings, donations of money to the Temple, and praises a widow's donation, \"...two very small copper coins, worth only a fraction of a penny.\" (42), over larger donations made by the rich. \"I tell you the truth, this poor widow has put more into the treasury than all the others. ...
Liquid Thorium Reactors Seem To Good To Be True. Is There Something Missing From What Ive Been Seeing on YouTube or Is It Solid Science?	They have downsides; - Molten fluoride salts are corrosive - Runs hot - Require expensive metal - Leaky unless you weld components - Beryllium fluoride is a carcinogen And from wiki, "when used in a breeder-like reactor, unlike uranium-based breeder reactors, thorium requires irradiation and reprocessing before the a...	[ "Advocates for liquid core and molten salt reactors such as LFTRs claim that these technologies negate thorium's disadvantages present in solid fuelled reactors. As only two liquid-core fluoride salt reactors have been built (the ORNL ARE and MSRE) and neither have used thorium, it is hard to validate the exact ben...
Science outside of your job	I always like to tell my students, particularly when I teach non physics majors, that the biggest skill you learn from physics is logical problem solving. You learn to take a complex problem, break it down into the most important factors contributing, various corrections to those leading order terms, and process comple...	[ "In schools, the science technician is the person who prepares the practical equipment and makes up the solutions used in school science labs. The role also includes instructing and assisting teachers with practical skills, including class demonstrations, for advanced techniques across all disciplines. Many are ver...
why do 30 second medication commercials spend 20+ seconds explaining worst case scenario risks and warnings?	The FDA heavily regulates Direct-to-Consumer Pharmaceutical Ads (DTCPA) that fall within three categories: 1) "Help-seeking" ads in which a condition and/or symptoms are briefly mentioned, discussed, portrayed by actors, etc..they don't state what the medication is and are intended to inform those who may identify with...	[ "In the United States, 20th Century Fox premiered a 40-second exclusive commercial during the 51st Super Bowl on February 5, 2017, which resembled a medication advertisement. An article in \"Vulture\" reviewed the television commercial, which noted: \"This spot that aired during the Super Bowl tonight may have tric...
why treadmills are bad for your knees? or if this is a myth?	Running is bad for your knees. The biomechanics of running on a treadmill are slightly different than running on the ground, but none of this is harder on your knees than running generally. In some cases, running on a treadmill is _better_ because it has a cushiony landing for you, reducing the impact to your joint. ...	[ "BULLET::::- Some treadmill runners develop bad running habits that become apparent when they return to outdoor running. In particular a short, upright, bouncy gait may result from having no wind resistance and trying to avoid kicking the motor covering with the front of the foot.\n", "A treadmill is a device gen...
Is there any truth to the stories of food tasters who tested food for poison?	You mean if they existed? I'm fairly sure they did, which is why being a [cupbearer](_URL_0_) for a monarch was such a prestigious position.	[ "BULLET::::- The safety of the food may be determined by observing whether or not the food taster subsequently becomes ill. However, food tasting is not effective against slow-acting poisons that take a long time to produce visible symptoms.\n", "BULLET::::- \"A Treatise on Adulterations of Food and Culinary Pois...
why does gum take so much longer to digest than other foods and where is it during that time?	While it's true that your body can't digest gum, the idea that it stays in your body a super long time (7 years, or whatever) is a myth. Same as if you swallowed a quarter, barring any complications, you'll pass it out of your system in a day or so, by the usual method. As to why you can't digest it, the simple answ...	[ "Chewing gum is rather shelf stable because of its non-reactive nature and low moisture content. The water activity of chewing gum ranges from 0.40 to 0.65. The moisture content of chewing gum ranges from three to six percent. In fact, chewing gum retains its quality for so long that, in most countries, it is not r...
why does it hurt to foam roll muscles?	You’re literally pulling on the muscle fibers in a concentrated area. The tighter the muscle, the more resistance. The more resistance the more it hurts as it gives.	[ "A foam roller is a lightweight, cylindrical tube of compressed foam. It may be used for many reasons, including increasing flexibility, reducing soreness, and eliminating muscle knots. Foam rolling is a method of self-myofascial release. Studies show that the best results occur when the foam roller is used for 30 ...
If a new particle is detected by how it decays, how can things like mass or spin be determined?	Primarily by knowing the inputs and the laws that they are subject to. For example, regarding mass and spin, there are two conservation laws which are related to these properites -- conservation of energy (related to mass) and conservation of angular momentum (related to spin). Due to these laws we know that the sums...	[ "Particle decay is a Poisson process, and hence the probability that a particle survives for time \"t\" before decaying is given by an exponential distribution whose time constant depends on the particle's velocity:\n", "So when physicists measure the spin of a particle along the -axis as, for example, , the part...
why anyone would be opposed to the iran nuclear deal?	It gives Iran back their money and opens revenue opportunities for them to sell oil and make even more money. Money they will likely use to expand all their weapons programs, thus threatening their neighbors. Threatened neighbors feel they have no choice but to use a first-strike strategy, leading to a war in the Mid...	[ "Benjamin Netanyahu, who called the Iran nuclear deal a \"historic mistake\", told President Barack Obama that Israel was under increased threat because of the deal and said in a statement, “In the coming decade, the deal will reward Iran, the terrorist regime in Tehran, with hundreds of billions of dollars. This c...
Why did Confession come to be such an important part of Christian (Catholic) faith in the 11th-13th centuries?	There has been an enormous amount written on this topic. Certainly people like Pierre Payer, R.I. Moore and others have offered some interesting observations. Moore famously argued that Fourth Lateran marked the beginning what he termed a "persecuting society" in which religious heterodoxy, confessional others, behavio...	[ "In the 16th and 17th centuries the term confession was only used for the documents of belief (cf. Confessio Augustana) while the religious communities of Roman Catholics, Lutherans, and Calvinists were referred to as “religious parties”, different “religions” or “churches” - not as confessions. In the late 18th ce...
Was Ancient Egypt's climate more lush and fertile than it is today?	You might find [this post I wrote in another thread](_URL_0_) interesting. It's about the desertification of Egypt and I linked a couple of figures showing how it proceeded.	[ "In Predynastic and Early Dynastic times, the Egyptian climate was much less arid than it is today. Large regions of Egypt were covered in treed savanna and traversed by herds of grazing ungulates. Foliage and fauna were far more prolific in all environs and the Nile region supported large populations of waterfowl....
why do congressional districts not follow county lines?	Congressional districts are created according to population size while county lines are created for various reasons (geography, politics, etc.) which have nothing to do with population and do not change according to population. Each congressional district must have about the same amount of population so they have to ...	[ "Senate district lines are drawn with an eye toward adhering to the boundaries of the state's 14 counties, and the districts are named after the county or counties in which the bulk of the district is located. However, due to equal representation requirements of the federal and state constitutions, most districts d...
how do cars not overheat when they cook outside in california/miami/texas heat for hours?	Running temp for an engine is usually around 195 degrees. Even the hottest of summer days does not approach that.	[ "During the early days of passenger railroading, cars were heated by a wood or coal fired stove—if any heat was provided at all. It was difficult to evenly heat the long, drafty cars. Passengers near the stove often found it uncomfortably hot, while those further away faced a cold ride. The stoves were also a safet...
Books on the Crusader States	You’re in luck! There’s been a bit of a resurgence in studies of the crusader states lately. And there are still lots of good old books too. For the crusader states in general: \- Andrew Jotischky, Crusading and the Crusader States (Routledge, 2013) \- Malcolm Barber, The Crusader States (Yale University Press, ...	[ "\"The Crusader\" was started by George Wells Parker, a black businessman from Omaha, Nebraska, as the official organ of the Hamitic League of the World, a pan-African nationalist group. Parker published articles in the journal proclaiming that Africa was the cradle of civilization and arguing the superiority of th...
China's coal consumption approaching that of the rest of the world combined... is this a major factor in global warming over the past 10 years?	This is a deceptively complicated question. Yes, the rise of CO2 emissions from China and, to a lesser extent, India are important, but the response also isn't instantaneous or linear. It's very difficult to be specific about causality when dealing with climate change, because there are a large number of forcings invol...	[ "As of 2015, China accounted for 50.0 percent of world coal consumption. Chinese coal consumption fell in 2014 and 2015. The last previous decline in Chinese coal consumption had been in 1997 and 1998. While consumption in China and the United States declined in 2015, that of India continued to rise and, in 2015, I...
Was there ever an earlier form of textspeak? Perhaps in the days of expensive telegraphs?	Textspeak from 1880: > The wire being unusually busy, this was all the conversation Nattie and "C" had during the day, but Just before six o'clock came the call, > "B m—B m—B m—X n." > "B m," immediately responded Nattie. > "I merely want to ask for my character before saying g. n. (good night). Haven't I been ...	[ "David Edward Hughes invented the printing telegraph in 1855; it used a keyboard of 26 keys for the alphabet and a spinning type wheel that determined the letter being transmitted by the length of time that had elapsed since the previous transmission. The system allowed for automatic recording on the receiving end....
what would happen to the internet/world if google suddenly went bankrupt and shut down?	We would start using Bing or whatever other services filled the void. There will be plenty of companies offering identical services to google. It probably won't be as good to start, and it won't be as integrated as google was, but it will develop pretty fast. There is an absurd amount of money to make from the services...	[ "Writers for \"Forbes\" have speculated on various situations which could end Google. In 2011 a writer described how Siri would end Google. In 2012 a writer described that nationalization of digital products could end Google. Another writer in 2012 argued that Google opposed the Stop Online Piracy Act by participat...
What is the connection between energy and information in a system?	Energy and entropy are independent thermodynamic variables. For a general system it is almost always possible to prepare a state with sensible given values of E and S.	[ "Systems theory at times seems to refer to information in this sense, assuming information does not necessarily involve any conscious mind, and patterns circulating (due to feedback) in the system can be called information. In other words, it can be said that information in this sense is something potentially perce...
why are bananas the classic slipping cliché in most cartoons?	Because... they're slippery.	[ "Banana peel is also part of the classic physical comedy slapstick visual gag, the \"slipping on a banana peel\". This gag was already seen as classic in 1920s America. It can be traced to the late 19th century, when banana peel waste was considered a public hazard in a number of American towns. Although banana pee...
how and why do almonds have a split directly down the middle?	Almonds are seeds, almond seeds are dicots, meaning they have 2 cotyledons. When you split the seed in half you are exposing each cotyledon Therefore both sides of the almond are not completely joined	[ "Almond butter is a food paste made from grinding almonds into a nut butter. Almond butter may be \"crunchy\" or \"smooth\", and is generally \"stir\" (susceptible to oil separation) or \"no-stir\" (emulsified). Almond butter may be either raw or roasted, but this describes the almonds themselves, prior to grinding...
In medieval Europe, did Arab musicians ever perform at court? Would European monarchs have been exposed to non-European music?	A [big chunk of the Iberian peninsula](_URL_3_) was ruled by Muslims (Arabs and Berbers) from the 8th century and until 1492. They were not just casually visiting, they built their own [palaces](_URL_5_) and [mosques](_URL_0_). Sicily was also conquered (they stayed for a while). They brought their music with them. T...	[ "The Moors of Al-Andalus were usually relatively tolerant of Christianity and Judaism, especially during the first three centuries of their long presence in the Iberian peninsula, during which Christian and Jewish music continued to flourish. Music notation was developed in Spain as early as the 8th century (the so...
Are there any misconceptions the public have about the Holocaust, that might be hard to explain without coming across as a Holocaust denier/revisionist?	Edit: It seems I misread OP's question a bit. My point remains the same though: It is very much possible to correct misconceptions on the Holocaust without coming across a denier depending on how you do it and what arguments you employ. If I am understanding the question the right way, the answer is no. With the wealt...	[ "Media reporting the 2017 controversy drew attention to a 2009 column in the \"Sunday Independent\" and \"Belfast Telegraph\" opposing laws against Holocaust denial. Despite accepting that \"the Nazis planned the extermination of the Jewish people\" and that \"millions of Jews were murdered\", Myers wrote \"I'm a h...
. why is the mustard pack at most fast food restaurants see through in the back when the mayo and the ketchup packets are not see through.	The main driver in packaging these days is price. Foil packaging provides the best moisture and oxygen barrier of the various types of sachets/packets out there but is by far the most expensive. If you find something in a foil packet, it is because when tested in a less expensive plastic variant it failed testing one w...	[ "In fast food outlets, ketchup is often dispensed in small sachets or tubs. Diners tear the side or top and squeeze the ketchup out of the ketchup packets, or peel the foil lid off the tub for dipping. In 2011, Heinz began offering a new measured-portion package, called the \"Dip and Squeeze\" packet, which can be ...
If nitrogen is so plentiful in the atmosphere, why do plants need to be fertilized with it?	It's not that anything's 'keeping' them from doing it, it's just that plants lack the ability to [fix nitrogen](_URL_0_), which means taking N2 gas from the atmosphere (which is chemically pretty inert) and turning it to ammonia, nitrate and other 'bioavailable' forms of nitrogen that they can use. There are bacteria ...	[ "Although nitrogen is plentiful in the Earth's atmosphere, very few plants can use this directly. Most plants, therefore, require nitrogen compounds to be present in the soil in which they grow. This is made possible by the fact that largely inert atmospheric nitrogen is changed in a nitrogen fixation process to bi...
why are baby animals cool with humans/other species, but adult animals are not?	Most animals have the instinct to rely on larger creatures (usually their parents) to survive. Partially because they are not ready to defend themselves yet. Baby birds can't fly away, baby cats don't have the strength to attack, etc. If you raise the animal from birth, it will think of you as a family member, but an...	[ "Adults and their young may be preyed upon by mammals such as the feral cat and red fox, reptiles such as goannas, rodents, and native predatory birds, such as the Australian magpie, butcherbird species, blue-winged kookaburra, crows and ravens, and shrike-thrushes.\n", "Development at birth varies considerably a...
why don't we ask primates to teach us their language(s)?	Do you have a source for this gesture language? I've heard if them knowing sign language that we've taught them but have never heard of them having their own	[ "Arbib puts forth a hypothesis that mirror neurons in the primate brain were a precursor to language abilities in humans. Without these neurons in Broca's area in humans (which is analogous to F5 in monkeys), Arbib claims, we could not have evolved a specialization for language—which is used to explain why non-huma...
what happens when you turn your automatic car off when it is still in drive? is it bad for the engine?	Not bad for it at all. If your car makes a sound it might be your car alone, try to record it and post it here, or /r/MechanicAdvice. If your on a hill and turn your car off without putting in Park, it will start to roll. The Park position on an automatic engages a small lock in the transmission to keep the car from ...	[ "Some vehicles will disarm if the ignition is turned on; often when the vehicle is equipped with a key-based immobilizer and an alarm, the combination of the valid key code and the ignition disarms the system.\n", "The stop-start feature will automatically switch off the engine when the car is idling at a complet...
How did Bronze Age pastorialists and/or early PIE speakers get their vitamin C and other micronutrients?	They almost certainly ate herbs in salads and stews, and herbs like cilantro and thyme and parsley have a lot of vitamin C. So do many fruits like strawberries and blueberries. Perhaps most important, though, are brassicas. Broccoli, cabbage, kohlrabi, and turnips all are rich in C (as well as a lot of other nutrients....	[ "PIE is estimated to have been spoken as a single language from 4500 BC to 2500 BC during the Late Neolithic to Early Bronze Age, though estimates vary by more than a thousand years. According to the prevailing Kurgan hypothesis, the original homeland of the Proto-Indo-Europeans may have been in the Pontic–Caspian ...
how come when phone screens break, they are still completely functional and readable, but when computer monitors or tvs break, they can no longer display the correct colors?	To explain it simply...when you break a monitor, you're breaking the screen directly. When you're breaking a phone screen for the most part, it's like breaking a glass panel placed over the monitor rather than the monitor itself. The glass is there for structural rigidity and to protect the LCD as LCDs are very, *very...	[ "This phone has a known LCD screen defect that causes the screen to cease functioning. T-Mobile was aware of this and only temporarily halted sales before putting the phone back on the market, regardless of the problem never being fixed. Upon further investigation, it appears as though the connector to the LCD beco...
Historians, how do you respond when people say that history is just "memorizing names and dates"?	There are two types of history to be discussed here. One, the type that is taught and state funded. This is the history that any given society is collectively supposed to know. Think about the question that asks [why the US education system goes back on itself](_URL_0_) after elementary school to clarify the inaccura...	[ "Historians consider knowledge of dates and events the primary content of history, or \"first-order knowledge\". They class historical significance as an aspect of the study of primary content, deeming it secondary or \"second-order knowledge\". However, the way dates and events are chosen and described is often us...
on wwii propeller planes, how did the nose guns shoot without damaging the blades?	With a [interrupter gear](_URL_0_). The technology was developed in WW1. It's a simple mechanism that blocks the gun from firing when the propeller blade is directly in front of gun.	[ "The aircraft did not have a nose engine, unlike many contemporary Italian designs. The SM.89 was a two-engine aircraft so that the nose could be used to house weapons. The nose section was rounded, short, and inclined sharply to provide good visibility for attacks on surface targets. The weaponry was mainly based ...
what is a police state?	A police state is where the government exerts harsh, rigid, totalitarian-like control over both social life and the economy. While it's impossible to define just when a nation becomes a "police state", there are a few traits we can note: * Possible apartheid tendencies, where social divisions are forced upon society ...	[ "Authority over a state police force is held by the state's home department, led by a chief or principal secretary (generally an Indian Administrative Service officer). Each state and union territory has a state police force (headed by a director general of police, an Indian Police Service officer), which is respon...
maybe i'm just young, but why was pulp fiction considered such a great movie?	So, first I should say that the actors in the movie weren't particular big time when they were in it. Most were either up and coming, worked with Tarantino previously, or washups. Second, you have to ask yourself what makes a good/great movie. I like to think that there are two major aspects to a great film the narra...	[ "the violent intensity of \"Pulp Fiction\" calls to mind other violent watershed films that were considered classics in their time and still are. Hitchcock's \"Psycho\" [1960], Arthur Penn's \"Bonnie and Clyde\" [1967], and Stanley Kubrick's \"A Clockwork Orange\" [1971]. Each film shook up a tired, bloated movie i...
Why did Belgium and the Netherlands split in 1830, and when they did, why did Flanders go with Belgium?	In a phrase, Great-Power maneuvering. What is now Belgium had, before the Revolutionary and Napoleonic wars, been the "Austrian Netherlands", part of the Habsburg imperial domains. The French annexed it in 1795 in the Peace of Basel. Naturally the Vienna peace conference, at which the Powers were pretty strongly motiva...	[ "In 1815, Belgium and the Netherlands were united in the United Kingdom of the Netherlands, and the province of North Brabant was established and so named to distinguish it from South Brabant in present-day Belgium, which seceded from the Kingdom in 1830. This boundary between the Netherlands and Belgium is special...
When did surnames begin being passed from parents to children for non-nobles in Europe?	It depended on the culture. In Iceland ~~today~~ as of 20 years ago, inherited surnames ("last names") are not done except for some grandfathering (no pun intended). In England, my source (Reaney and Wilson, citing Fransson) suggests that hereditary surnames were in the nobility in the 12th century, in the general po...	[ "By 1400, most English and some Scottish people used surnames, but many Scottish and Welsh people did not adopt surnames until the 17th century, or later. Henry VIII (ruled 1509–1547) ordered that marital births be recorded under the surname of the father. In England and cultures derived from there, there has long ...
what does david cameron's resignation as prime minister mean for britian and the rest of the world?	Basically, nothing. David Cameron steps down as prime minister someone from the Tory party will be voted to be their leader/representative and become the new prime minister. That's it really.	[ "Following the vote by the British electorate in favour to leave the European Union on 23 June, Cameron announced that he intended to step down as Prime Minister following the Conservative Party conference in the autumn of that year during a televised speech on the morning of 24 June 2016. Cameron, who had campaign...
Why is pubic hair rarely depicted in ancient and medieval art?	not discouraging anyone from contributing more info, but you may be interested in this related post from a few months ago: [How come in Renaissance style paintings (and even further back with Greco-Roman art) all the women who are nude are hairless? Was it an attempt to just show purity, or did higher class women shav...	[ "In works of art, the underarm hair is usually removed; showing it is a mark of modernism. This contrasts to the depiction of pubic hair in art, which is rarely portrayed in works created in the Middle Ages, increasingly common in Renaissance art, and quite frequent in modern times.\n", "In ancient Egyptian art, ...
Have we discovered a planet or moon that has geosynchronous orbit around a star or planet?	> Is the moon in geosynchronous ordbit around the Earth? Seeing as the Moon orbits once every 28 days, but the Earth rotates once per day, no. I think you could state that Earth is in synchronous orbit around the moon, though (both objects orbit each other, and the Moon's day is equal to the orbital period). A synch...	[ "During the photometric observation in July 2009, a minor-planet moon, designated , was discovered orbiting \"Climenhaga\" with an orbital period of 18.954 hours. The discovery was not announced until 2013. The satellite's orbit has an estimated semi-major axis of 19 kilometers.\n", "The discovery of a minor-plan...
can anyone eli5 the moment generating function?	It's hard to ELI5 since no five year old will know anything about basic probability theory or function transforms. Perhaps I'll first just explain the name. The nth moment of a random variable is the value E[X^n]. Each moment tells us a little more about that variable's distribution. The mean E[X] tells us the mean...	[ "As its name implies, the moment generating function can be used to compute a distribution’s moments: the \"n\"th moment about 0 is the \"n\"th derivative of the moment-generating function, evaluated at 0.\n", "Excitation function is a term used in nuclear physics to describe a graphical plot of the yield of a ra...
are are zoo animal births less successful than in their natural habitats? if so... why?	Zoo animals births are 1000x more successful than in the wild. Zoos aren't just a place for entertainment. It a rehabilitation center focusing on saving species. If an animal is born in a zoo there's a WHOLE medical staff ready to jump in if there's any signs of distress or issues. The baby then gets checked their ...	[ "Thanks to its remarkable birth rate, the zoo is able to adhere to many programmes of safeguard of species in the process of extinction. In 2006 for example, the zoo took part in 36 European breeding programs, thus, a quarter of the 130 species which it shelters is the subject of an international program of breedin...
how is the speed of an airplane calculated when it is in the air?	A pitot tube located on the outside of the aircraft in the airflow, measures the airflow and indicates the velocity in the airspeed indicator inside the cockpit or a GPS which uses satellites.	[ "This gives us the velocity of the aircraft right after it takes off. Because we know all forces acting on it from this point on, we can calculate net acceleration using Newton's second law. Given the velocity that the aircraft takes off with and the acceleration at any point, the velocity can also be calculated at...
why do they say pinching yourself will wake you from a dream? how can someone control the substance of their "lucid dream"?	Studied and practiced lucid dreaming for a couple years. To answer your first question, pinching yourself in your dream can cause a pain response. When you dream, the logic center of your brain goes into a resting state, that's why in dreams everything is "seeing is believing". When you pinch yourself in a dream and in...	[ "Oftentimes people experience external stimuli, such as an alarm clock or music, being distorted and incorporated into their dreams. Freud explained that this is because \"the mind is withdrawn from the external world during sleep, and it is unable to give it a correct interpretation ...\" He further explained that...
What was the War of 1812 like for a regular British soldier?	I would suggest looking at resources pertaining to the Napoleonic Wars such as "The Letters of Private Wheeler 1809-1828", edited by B.H.Liddell Hart, or "25 years in the Rifle Brigade" by William Surtees. The latter author started his career in 1799. If you wish information on just the War of 1812 you may have to dig...	[ "Edward Baynes (1768–1829), was an officer in the British Army. He served, mainly in staff roles, during the French Revolutionary Wars and Napoleonic Wars. However, he is best known for serving as one of the principal staff officers in British North America during the War of 1812 between Britain and the United Stat...
We all know that medieval and renaissance blacksmiths were flipping good. But what tools did they use? I'm especially interested in how could they have vices without screws and how the hell could they manufacture files	I hope the mods will allow this, I am not a historian, but I am a blacksmith who specifically trained in a renaissance style shop. The only concessions we made to modern practices were the use of coal / coke instead of charcoal and we bought files because they are difficult to make well. First, they are probably not ...	[ "The ancient traditional tool of the smith is a forge or \"smithy\", which is a furnace designed to allow compressed air (through a bellows) to superheat the inside, allowing for efficient melting, soldering and annealing of metals. Today, this tool is still widely used by blacksmiths as it was traditionally.\n", ...
with an infinite spectrum of frequencies to choose from, why does everything use 2.4ghz?	We use lots of frequencies for all sorts of things! Here's a map for how frequency is used in the US: _URL_0_ If you zoom right in near the end of the 300MHz - 3GHz spectrum you'll see "amateur" at around 2400: _URL_1_ That's a region of frequency reserved for anyone to use without a license. It happens to have rea...	[ "As more digital appliances based 2.4GHz frequency band, it could be easy to interfere with the communication of 2.4G wireless conference system. Consequently, 5.8 GHz frequency band is applied in some wireless conference systems. In some cases, there are dual-band conference system that could change the communicat...
how much would it really matter if tomorrow, the moon was gone?	* There would be no more tides, possibly causing problems for many high tide ports around the world, but they would adapt. * Animals that use the moon for navigation or night vision would be confused. * Animals that use the tides as part of their life cycle (for example, giving birth in tide pools) would probably be de...	[ "The Doctor and Sam must piece together a centuries-old puzzle. How can Janus Prime’s moon weigh billions of tons more than it should? Why is the planet riddled with deadly radiation? As the violence escalates around them, will the time travellers survive to discover the answers?\n", "Currently, the Moon is movin...
Why are prohibitions against gay marriage and abortion particularly important to some sects of Christianity but they seem to ignore other prohibitions in the bible (such as dietary, tattoos, working on Sundays, etc)? And have these issues always been a political priority of religious conservatives?	I see questions about modern fundamentalism (which I assume are a part of the 'some sects' your refering to) come up here from time to time - some of them get almost no (good) responses, some generate some good discussions (even if some are conflicting). I hope this generates some good responses as I'd love to hear t...	[ "The Prohibitionists comprise strict followers of the Bible. They believe that \"homosexuality is an aberration, homosexual acts are an abomination,\" homosexuality is an illness that requires a cure, and that homosexual acts should be punished. Sullivan argues that there is inconsistency with Prohibitionists who u...
What did Socrates mean when he said "military training is not publicly recognised by the state" when regarding the topic of fitness?	Ancient Greece (particularly the polis) are fascinating to study. The short answer would be that in these polis (ie. Athens, Corinth, etc) there was no standing army and, as Socrates states, wasn't any military training programs administered by the 'state' (in this passage that word is likely very loosely translate...	[ "Socrates and his companions Adeimantus and Glaucon conclude their discussion concerning education. Socrates breaks the educational system into two. They suggest that guardians should be educated in these four virtues: wisdom, courage, justice and temperance. They also suggest that the second part of the guardians'...
What were some common Roman curses and insults?	[Pedicabo ego vos et irrumabo](_URL_0_)	[ "In English, swear words and curse words tend to have Germanic, rather than Latin etymology \"Shit\" has a Germanic root, as, likely, does \"fuck\". The more technical alternatives are often Latin in origin, such as \"defecate\" or \"excrete\" and \"fornicate\" or \"copulate\" respectively. Because of this, profani...
Any diseases/disorders/pathologies known to history but never witnessed by modern doctors?	It's a disease rather than a psychological disorder, but the 'Sweating Sickness' that afflicted Britain and parts of mainland Europe during the late 15th and early 16th centuries. It spread very fast and apparently had a high mortality rate, killing off several high profile victims including Arthur, the Prince of Wales...	[ "Throughout history people have written about diseases, how human beings might contract them and what could be done to remedy it. Medicine ranged from folklore, witchcraft to the current evidence-based medicine. Among the most notable descriptions are texts from Egypt (Imhotep, \"Edwin Smith Papyrus\", \"Ebers Papy...
We often use decades to refer to the distinct cultural and political eras of past century. Is this a recent understanding, or did historians of previous centuries also use "decadeology"?	There's a pretty good answer [here](_URL_0_) from a few months ago, based mostly on popular culture.	[ "BULLET::::- Particularly in the 20th century, a nominal decade is often used to refer not just to a set of ten years but rather to a period of about ten years - for example, the phrase \"the sixties\" often refers to events that took place between around 1964 and 1972, and to memories of the counterculture, flower...
How would it sound to hear a pitch being lowered out of the human range of hearing?	There is not a cliff that pitch perception of sound falls off. A pure tone (a sine wave) will be audible as a tone down until about 25Hz, when (assuming it is being reproduced loudly enough) it starts to become perceived as a feeling in the body rather than a tone in the ears. At below 15Hz it is a shuddering sensation...	[ "A special type of pitch often occurs in free nature when sound reaches the ear of an observer directly from the source, and also after reflecting off a sound-reflecting surface. This phenomenon is called \"repetition pitch\", because the addition of a true repetition of the original sound to itself is the basic pr...
the concept of work in physics? details inside.	The key to this concept is that there is a difference between force and work. Force describes a potential, which means that if you apply force to something, but fail to move it, it only has the potential to move (if, for example, obstacles are cleared). When you are grunting and pushing and shoving on something immov...	[ "Work is the energy transfer associated with an ordered, macroscopic action on the system. If this action acts very slowly, then the adiabatic theorem of quantum mechanics implies that this will not cause jumps between energy levels of the system. In this case, the internal energy of the system only changes due to ...
what is the difference between permutations and combinations.	When discussing permutations, the order of the items selected is counted: two sets of items with the same members, but chosen in a different order, are respected as a distinct permutation. Ie the sets [1 2 3] and [2 1 3] out of a set of the positive integers from 1 to 100 would be distinct permutations, but one combi...	[ "In mathematics, a combination is a selection of items from a collection, such that (unlike permutations) the order of selection does not matter. For example, given three fruits, say an apple, an orange and a pear, there are three combinations of two that can be drawn from this set: an apple and a pear; an apple an...
what does it mean when drinks are only 20% juice? what is the other 80%?	Most likely added water and added sugar. Take a glass. Fill it 1/5 full of orange juice. Fill the rest of the cup with Crush orange soda. You now have a 20% juice orange drink.	[ "Depending on trends and regulations, beverages listed as \"100% juice\" may actually contain unlisted additives. For example, most orange juice contains added ethyl butyrate (to enhance flavor), vitamin C (as ascorbic acid), and water (if from concentrate). When fruit juice is too sour, acidic, or rich to consume,...
why are horses put down when they get injured racing. why not have them recover and live their lives out.	Because you'd have to keep a horse off it's feet to allow the injury to heal Horses sleep, eat and do everything else standing . Other than occasionally lying down when rem (rapid eye movement) sleep is needed. That should show you how not worth the work that process of trying to heal it would be. Some racehorses ar...	[ "The level of treatment given to injured Thoroughbreds is often more intensive than for horses of lesser financial value but also controversial, due in part to the significant challenges in treating broken bones and other major leg injuries. Leg injuries that are not immediately fatal still may be life-threatening ...
why are humans more intrigued by negativity and malice than positivity and good?	Because "good" is supposed to be normal. People generally aren't intrigued by normal. Think of it this way: "All planes land safely" is not newsworthy. And it shouldn't be--that is what is supposed to happen. A plane crash is an outlier, and thus intriguing.	[ "The negativity bias is noticeable in a plethora of situations related to the formation of risk-averse behaviour. Notably, any stimuli that evokes the expression of fear encourages risk -aversion. The human brain has adapted to easily parse out these stimuli from a sea of benign stimuli. In the laboratory, particip...
How is it possible to have two suns? (NASA's pic of the day)	Roughly half of the stars in the galaxy are part of a binary system. If the two stars are about the same mass, then they'll orbit around a common point in space between them. If one star is a lot more massive than the other, then the smaller star will orbit around the larger star just like a planet does. [Sirius, one o...	[ "This star is considered a solar analog—meaning that it is photometrically analogous to the Sun. Like the Sun, it has a magnetic activity cycle. It shares a common proper motion through space with the spectroscopic binary star system HD 122742, and in the past the three may have formed a triple star system. In the ...
Do cancer cells keep multiplying after the patient's death? If yes, how long?	Unless the cancer cells are purposefully kept alive by researchers, as in Ed's post, after the patient's death they will die in very short order. Cancer cells are in general at least as vulnerable to loss of blood flow as a normal cell, as demonstrated by many cancers' propensity to develop areas of necrosis (dead tis...	[ "A disregulation of the cell cycle components may lead to tumor formation. As mentioned above, when some genes like the cell cycle inhibitors, RB, p53 etc. mutate, they may cause the cell to multiply uncontrollably, forming a tumor. Although the duration of cell cycle in tumor cells is equal to or longer than that ...
how did single cell organisms evolve into having things like eyes which seems like one of the senses that would evolve out of nowhere?	Organisms didn't go straight from single-cells to having eyes. There are lots and lots and lots of steps in between. If you're interested, though, [this diagram](_URL_0_) shows the basic steps of how we think the eye evolved. Basically, the organism starts with just a patch of vaguely light-sensitive skin cells. T...	[ "Whether the eye evolved once or many times depends on the definition of an eye. All eyed animals share much of the genetic machinery for eye development. This suggests that the ancestor of eyed animals had some form of light-sensitive machinery – even if it was not a dedicated optical organ. However, even photorec...
what is the process of remastering old films/movies? also, as a followup, how long does this typically take?	Strangely, (at least it seems strange to some people) regular old film is extremely detailed, somewhere around 25 megapixels per image. In order to distribute a movie, it gets converted to an easier-to-use format, but this process loses some of the detail. This isn't a problem because if they convert it to DVD, for exa...	[ "Remastering is the process of making a new master for an album, film, or any other creation. It tends to refer to the process of porting a recording from an analogue medium to a digital one, but this is not always the case.\n", "Of course, having an intermediate digital stage, followed by forming a new film mast...
What were the typical sleeping times before the invention of electricity? Or even better, what is the oldest historic reference to the sleeping patterns of a culture?	Side question: is there a recent cultural (medical?) history of sleep? That would be awesome book. I'd love to know how medical ideas of sleep changed in the past two or three centuries. Is there a biopolitical dimension to sleep? Did the development of clinical medicine change understandings of sleep? Edit: There's *...	[ "A 16th-century physician wrote that many laborers dozed off exhausted at the start of each night; sexual intercourse with their wives typically occurring in the \"watching period\", after a recuperative first sleep. Anthropologists find that isolated societies without electric light sleep in a variety of patterns;...
hardware encryption	The only difference is that the encryption is done with specialized hardware, not with software. Because it is done on special hardware, it is generally faster and can be more difficult to crack. If an encryption scheme is done correctly, it will be impossibly difficult to crack in a reasonable amount of time. Even ...	[ "Hardware-based encryption is the use of computer hardware to assist software, or sometimes replace software, in the process of data encryption. Typically, this is implemented as part of the processor's instruction set. For example, the AES encryption algorithm (a modern cipher) can be implemented using the AES ins...
do bird feathers decompose?	yes. its literally hair and a soft form of keratin(the stuff your finger nails are made of), so it would take about as long as a finger nail would take to decompose. like around a full year to decompose completely.	[ "Displaced feathers can cause birds considerable trouble; such feathers might become damaged, could interrupt the smooth flow of air over a flying bird, or might allow the bird's body heat to escape. Preening allows a bird to reposition such displaced feathers. There is evidence that filoplumes, specialized feather...
last month, yitang "tom" zhang proved the twin prime conjecture, one of math's oldest problems. what is the conjecture and how did he do it?	He did not prove the twin prime conjecture, but he did prove something that is directly related to the twin prime conjecture. The twin prime conjecture is very simple: There are infinitely many pairs of primes that differ by 2. For example, 3 and 5 are twin primes, because their difference is two. 11 and 13 are t...	[ "The link was initially dismissed as unlikely or highly speculative, but was taken more seriously when number theorist André Weil found evidence supporting it, though not proving it; as a result the conjecture was often known as the Taniyama–Shimura–Weil conjecture. It became a part of the Langlands programme, a li...
how do countries get their names?	Really, they're named for all sorts of different things. - Some of them are named for the ethnic groups that resided there before modern countries emerged — Britain, probably, for a celtic-speaking tribe that the Greeks wrote about in the 4th century BC. - Some are named for individuals — America, for Amerigo Vespucc...	[ "In Ido, country names must conform to the language's orthography but otherwise many are left unchanged: \"\", \"\", \"\". Many other countries have their names translated, as \"\" for Germany, \"\" for Chile, \"\" for the United States or \"\" for China.\n", "onlyincludeMost countries of the world have different...
When a geographically isolated population becomes reproductively isolated from previously interbreeding populations, what exactly changes to make them incapable of interbreeding?	Reproductive isolation is the state where 2 populations of organisms do not breed with one another. Reproductive isolation can be achieved a great number of ways in the wild. Two populations which are geographically so far apart they never encounter one another are said to be reproductively isolated due to their ge...	[ "However, if the separating factor is removed before this happens (e.g. a road is cut through the forest), and the individuals are allowed to move about freely, the individual populations will still be able to interbreed. As the species's populations interbreed over time, they become more genetically uniform, funct...

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