question stringlengths 3 301 | answer stringlengths 9 26.1k | context list |
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what is torque? | Alright so the easiest way to get the concept of torque is to look at a loooooong pole. This pole has a certain mass and nothing will necessarily change that. However if you hold it at the center you'll notice that it is incredibly easy to balance. Now try to hold that rod at the way end while also trying to keep it ba... | [
"Torque, moment, moment of force or \"turning effect\" is the rotational equivalent of linear force. The concept originated with the studies of Archimedes on the usage of levers. Just as a linear force is a push or a pull, a torque can be thought of as a twist to an object. Another definition of torque is the produ... |
Why does eating spoiled food which has been cooked still make us sick? | Food may spoil and become toxic or irritating if a certain kind of bacteria infected it and left behind toxins or concentrations of something our bodies will reject. Also, certain bacteria can survive relatively high temperatures for short times like dormant botulism spores.
Once bacteria gets moving and colonies for... | [
"Eating deteriorated food could not be considered safe due to mycotoxins or microbial wastes. Some pathogenic bacteria, such as \"Clostridium perfringens\" and \"Bacillus cereus\", are capable of causing spoilage.\n",
"Issues of food spoilage do not necessarily have to do with the quality of the food, but more so... |
Is a photo of a primary source a primary source itself? | A photo of a newspaper article or other primary source is merely documentation of that source. It is not a secondary source, as it offers no interpretation of the primary source. It is merely a means to an ends. If you were to alter the photograph, as in [Marcel Duchamp's famous *L.H.O.O.Q.*](_URL_0_), then you would h... | [
"Many sources can be considered either primary or secondary, depending on the context in which they are used. Moreover, the distinction between \"primary\" and \"secondary\" sources is subjective and contextual, so that precise definitions are difficult to make. For example, if a historical text discusses old docum... |
howcome certain car models have so many of-brand replicas (eg. ac cobra, lotus 7, porsche 356), when most classic, desirable cars have none? | It's all about intellectual property. Companies like Ford, Lotus and Porsche have made deals with smaller companies to allow them to build replicas, based on the original designs.
Ferrari would never allow someone else to dilute the brand image and exclusivity. Keep in mind more availability makes rare classics less ... | [
"The company offers standard replicas of Lotus Seven and Porsche 550. Also offered are special order replicas of cars like: Maserati 300S, Lancia D24, Ferrari 375 MM, Alfa Romeo 3000 CM, Frazer Nash Le Mans and other racing cars from the period. All of the cars have aluminium bodies.\n",
"Legends cars are a \"spe... |
why is nationalism and patriotism so prevalent when global human rights advancement should be our natural inclination? | Here's let's ask another question: "Why are globalism and human rights so prevalent when patriotic nationalism should be our natural inclination?"
Let's try again: "Why are patriotism and globalism so prevalent when national human rights advancement should be our national inclination?"
We can keep going and going. | [
"English Historian G. P. Gooch in 1920 argued that \"While patriotism is as old as human association and has gradually widened its sphere from the clan and the tribe to the city and the state, nationalism as an operative principle and an articulate creed only made its appearance among the more complicated intellect... |
Have empires in decline historically been able to rebound? What, if any, are the most notable examples of this occurring? | [Justinian the I](_URL_0_) and his general Belisarius made a solid effort in the Byzantine renovatiio imperii to reclaim the Western Roman Empire in the mid sixth century. The Byzantine resurgence under him reclaimed, at the greatest extent, large parts of North Africa, Spain, Italy, and the Balkans, although he never ... | [
"The empire eventually died out because of many factors such as substantial loss of territory and imperial authority caused by their own erstwhile feudatories, as well as the invasion by the Huna peoples (Kidarites and Alchon Huns) from Central Asia. After the collapse of the Gupta Empire in the 6th century, India ... |
Why did hunting ever become a way to gather food when simply trapping animals is much more efficient? | Hi, this question is about human behaviour that reaches deep into *prehistory* (and even pre Homo Sapiens). For that reason, it would be worth x-posting to our sister sub /r/AskAnthropology. While there are some anthropologists here, there are more there, and with greater focus on earlier time periods and human evoluti... | [
"In the 1970s optimal foraging theory was developed by anthropologists and ecologists to explain how animals hunt for food. It suggested that the eating habits of animals revolve around maximizing energy intake over a given amount of time. For every predator, certain prey are worth pursuing, while others would resu... |
Why does the flame of a cigarette lighter aid visibility in a dark room, but the flame of a blowtorch has no effect? | Burning things like matches or a lighter isn't very efficient, it produces soot (carbon) which glows when heated.
A blowtorch is much more efficient. There's more heat in a blowtorch flame so it burns away the soot and thus has less material in the flame to glow and produce light.
The glowing of material through h... | [
"The drawbacks of gas lighting were overheating of the air and extremely high oxygen consumption, making it necessary to ventilate the room or isolate the flame by separating the room where the combustion took place from the room being lit. Theatre audiences regularly suffered from headaches and the sulphur and amm... |
What type of devices / technology will memristors allow that can not be created without their use? | Memristors could potentially replace both ram and hard drive memory. It could potentially have a much greater memory density while providing similar access times as ram.
_URL_0_ | [
"It's possible to adapt structures from classical electrostatic induction generators, which also extract energy from variable capacitances, for this purpose. The resulting devices are self-biasing, and can directly charge batteries, or can produce exponentially growing voltages on storage capacitors, from which ene... |
I heard somewhere that the "natural born citizen" requirement for the U.S. presidency was added to the U.S. Constitution to prevent Alexander Hamilton from becoming president. Is there any truth to this? | Finally, a question I can answer!
First and foremost, there was nothing keeping Hamilton from running, except his political apathy (and death by gunshot wound). Nobody was a natural born citizen at that point, they were all British subjects, and Hamilton, while born in the Caribbean (Barbosa i believe) was still a Bri... | [
"BULLET::::- The United States Constitution appears on a cursory reading to stipulate that presidential candidates must be natural born citizens of the United States. However, there is a further category of persons eligible for that office, now exhausted: those who were citizens of the United States at the time of ... |
what is to have trust in something? why does it take so much time to trust something but it takes so little to lose trust? | Imagine you have a barrel that collect rain water. Rain drops will fill it slowly, but even the smallest hole can bleed the barrel drop in a short time. | [
"Trust is integral to the idea of social influence: it is easier to influence or persuade someone who is trusting. The notion of trust is increasingly adopted to predict acceptance of behaviors by others, institutions (e.g. government agencies) and objects such as machines. However, once again perception of honesty... |
How do space probes keep their batteries from dying in the freezing cold temperatures of space? | Heaters. In some cases it's purely electric; in some cases it's waste heat from a radioactive power source. As you've surmised, thermal management on spacecraft is a huge problem. A satellite facing the sun may be boiling hot on one side and freezing cold on the other - the heat must be channeled and controlled, to ... | [
"5 September 2007: Spacecraft computer froze as a result of unknown influences, most likely radiation-induced upsets. This happened while the spacecraft was in full sun and with the power drains (30 W) on to prevent battery overcharging. Without the computer to cycle the drains off, the spacecraft remained in a con... |
the black-scholes options pricing model and how it was used in hedging and why it ultimately failed after doing so well when used by the options traders. | > ELI5 advanced stochastic calculus.
Sure!
No really, I'll try:
Black Scholes option pricing and hedging is basic and rely on informations you collect on the market such as volatility.
You can't compute instant volatility and expected volatility. You derive it from the prices you observe on the market and then appl... | [
"Closely following the derivation of Black and Scholes, John Cox, Stephen Ross and Mark Rubinstein developed the original version of the binomial options pricing model. It models the dynamics of the option's theoretical value for discrete time intervals over the option's life. The model starts with a binomial tree ... |
why is boston always depicted as a major irish town, like even more than "close" cities on the east coast? | When the bulk of irish immigrants made their way stateside (potato famine time frame) , NYC was already crowded with many nationalities. Boston was more open and still had a good port location. | [
"Boston today has the largest number of Irish-Americans of any city in the United States. During the Celtic Tiger years, when the Irish economy was booming, the city saw a buying spree of residences by native Irish as second homes or as investment property.\n",
"Since before the start of the American Revolution, ... |
Where sensors and analysis measure global temperature? | Global Surface Temperature data and a description of how it's created can be found [here](_URL_0_). This process uses data from meteorological stations around the world and more recently (around 1995), ships and buoys are used to estimate ocean air temperature from sea surface temperature. With the Argo network I imagi... | [
"Satellite temperature measurements are inferences of the temperature of the atmosphere at various altitudes as well as sea and land surface temperatures obtained from radiometric measurements by satellites. These measurements can be used to locate weather fronts, monitor the El Niño-Southern Oscillation, determine... |
why we can blow hot or cool air just by changing the shape of our mouths. | You can only blow hot air. However, when you purse your lips and blow, the narrow opening causes the air to speed up, and faster airflows are better at pulling in surrounding air. So that air that you're feeling in that case is partly air from your lungs, and partly cooler air from the surrounding environment.
Try l... | [
"Oral temperatures are influenced by drinking, chewing, smoking, and breathing with the mouth open. Mouth breathing, cold drinks or food reduce oral temperatures; hot drinks, hot food, chewing, and smoking raise oral temperatures.\n",
"The human nasal passages serve as a heat exchanger, with cool air being inhale... |
What causes a battery short to damage the battery, as opposed to being in a circuit? | The amount of current - essentially, electrons per second - that you're pulling out of the battery depends on the battery voltage and the resistance of what it's connected to. A light bulb has some non-negligible resistance, whereas a short wire would have less than 1 Ohm of resistance.
So pulling a lot of curren... | [
"The effect can be overcome by subjecting each cell of the battery to one or more deep charge/discharge cycles. This must be done to the individual cells, not a multi-cell battery; in a battery, some cells may discharge before others, resulting in those cells being subjected to a reverse charging current by the rem... |
All through school I was taught that (classical) Roman and Greek culture were extremely similar, because the Romans copied Greek culture. How reasonable do you think that claim is? |
The Romans did adopt some areas of Greek culture, many Greeks were taken as slaves and served as teachers and doctors in households, however the Romans admired the Greeks of around the 4th century BC as great heroes and legends whilst they considered the Greeks that were around in their time to be little more than a w... | [
"The culture of the ancient Greeks, together with some influences from the ancient Near East, was the basis of art, philosophy, society, and educational ideals, until the Roman imperial period. The Romans preserved, imitated and spread over Europe these ideals until they were able to competitively rival the Greek c... |
is creativity natural? if not, which are the steps to emerge creativity? | Creativity is definitely a mix of confidence and knowledge/experience. You need confidence because you need to not be afraid to fail. To make something novel, you have to risk doing things that haven't been done before, and doing such may result in failure or low returns. You also need knowledge and pretty much exp... | [
"From an evolutionary perspective, creativity may be a result of the outcome of years of generating ideas. As ideas are continuously generated, the need to evolve produces a need for new ideas and developments. As a result, people have been creating and developing new, innovative, and creative ideas to build our pr... |
What were some interesting historical rude gestures? | In 17th century England MPs farted during parliamentary speeches to show their derision. | [
"Various public figures such as the French basketball player Tony Parker, footballer Nicolas Anelka and National Front founder Jean-Marie Le Pen were pictured making the gesture. A new trend emerged, consisting of performing quenelles beside unwitting public figures identified as members of the establishment (such ... |
Who are Russia's oligarchs and how did they become rich? | Put simply, the term 'Russian Oligarch' refers to Russian businessmen who rapidly accrued large amounts of wealth through the purchasing of Soviet assets after the dissolution of the Soviet Union (1991). Effectively business magnates, they saw the opportunity of the Soviet Union's vast production assets (factories, min... | [
"Russian oligarchs are business oligarchs of the former Soviet republics who rapidly accumulated wealth during the era of Russian privatization in the aftermath of the dissolution of the Soviet Union in the 1990s. The failing Soviet state left the ownership of state assets contested, which allowed for informal deal... |
Did the Council of Ephesus effectively end Nestorianism in the West, and, if not, what measures would the Church have taken to combat the heresy afterwards? | This is a great question, thanks for asking it.
Let's start with some background. Nestorius was an Antiochene monk who had been installed as the Bishop of Constantinople in the Spring of 428. Early in his career, he preached against the title θεοτόκος (*Theotokos* or "God-bearer") for Mary, the mother of Jesus, offer... | [
"The result of the Council led to political upheaval in the church, as the Assyrian Church of the East and the Persian Sasanian Empire supported Nestorius, resulting in the Nestorian Schism, which separated the Church of the East from the Latin Byzantine Church.\n",
"The adoption of Nestorius' teaching, who had b... |
How stringent was the Ancient Spartan eugenics program? | The problem with the Spartans is that we know very little about them in reality. The vast majority of the image you probably have of Spartan society, particularly with the *agoge* and the strict communal living situation, comes from sources writing centuries after the fact in an environment of intense romanticization a... | [
"The free practice of eugenics could lead not only to the development of stronger individuals, but also of strains endowed with more endurance, intelligence, and courage. These strains should constitute an aristocracy, from which great men would probably appear. Modern society must promote, by all possible means, t... |
What were the early settlements like in New Spain in the 16th century? | It's hard to group all of New Spain into one group, as there are multiple stories that can be told from the Aztecs to the Maya. Broadly speaking, the origins of New Spain are with the destruction of the Aztec Empire in 1519 by Cortés. Prior to beginning his war, Cortés and his soldiers received aid and shelter from ene... | [
"There is little reliable information about the area for the 16th century, just after the Spanish conquest of the Aztec Empire. Some state that the first Spanish settlement was founded by Álvar Núñez Cabeza de Vaca in 1530, near Huépac. Others state that Francisco Vásquez de Coronado founded a village on the edge o... |
why do women live on avg longer than men? | For one, men tend to be at higher risk for accident. This is due partly to male culture and partly to men's historically being the more common participants in war.
Beyond this, males are more at risk for many diseases due to the nature of XY sex determination. While females have an XX sex determining chromosomes, men... | [
"Evidence supporting this theory comes from disease studies showing that women who reach menopause later have less heart disease and stroke, less dementia, and less osteoporosis, supporting the theory that the longer the HPG axis is in balance, the less likely one is to develop age-related diseases. Conversely, ear... |
How did cultural norm shifts define the transition from classical to modern day music? [X-Post from r/music] | This is quite a big question. As caffarelli said, it reaches into the philosophical realm. I will try to comment on some things that can be considered relevant.
> why are all of the periods so different from one another?
Because they are meant to be that way. These tags/names/periods/whatever were created to have a... | [
"Classical music is art music produced or rooted in the traditions of Western culture, including both liturgical (religious) and secular music. While a more precise term is also used to refer to the period from 1750 to 1820 (the Classical period), this article is about the broad span of time from before the 6th cen... |
why does seeing other people bite down on popsicles hurt my own teeth? | I don't have any links but this is what I remember from a range of readings.
Humans are wired to be social - hence the large brain to hold all those social interactions. Survival in humbers etc. Which influences everything from the smile to the catchy effect of the yawn.
We have "mirror neurons" which, you guessed it,... | [
"Eating hard foods (e.g., crisps) can damage the lining of the mouth. Some people cause damage inside their mouths themselves, either through an absentminded habit or as a type of deliberate self-harm (factitious ulceration). Examples include biting the cheek, tongue, or lips, or rubbing a fingernail, pen, or tooth... |
why cant you vote across party lines during a election, but not a primary? | Primaries are run by parties. Parties set their rules about who can vote. This is state by state, though. Some states have what are called "open" primaries, where you wouldn't need to declare a party to vote in the primaries. | [
"Primaries can be used in nonpartisan elections to reduce the set of candidates that go on to the general election (\"qualifying primary\"). (In the U.S., many city, county and school board elections are non-partisan.) Generally, if a candidate receives more than 50% of the vote in the primary, he or she is automat... |
why is it that when you stretch your foot and it cramps it is such horrible pain you think you are going to die? | Its basically muscles that are unable to relax due to deficiency in minerals within the foot or a low energy reserve.
This, being unable to contracts stimulates the nerves in the foot extremely and that hurts. | [
"Stretching for too long or too much can give way to an injury. For most activities, the normal range of motion is more than adequate. Any sudden movements or going too fast can cause a muscle to tighten. This leads to extreme pain and the performer should let the muscle relax by resting.\n",
"Some people get inj... |
What are some good American History primary sources to teach my 9th graders about how to analyze history? | I am very partial to the Stanford History Education Group. They have tons of lessons for World and US History that involve analyzing primary sources. And the best part is they are all free. The only downside is that they can be pretty paper-intensive though you can easily turn them into digital lessons.
Explore the si... | [
"CHNM and the Stanford History Education Group have worked on other projects together, including Historical Thinking Matters, a website focused on key topics in U.S. history that is designed to teach students how to critically read primary sources and how to critique and construct historical narratives.\n",
"The ... |
Is the current amount of Islamic jihad attacks a modern phenomena? | *Jihad* (lit: Struggle/strive) itself is an interesting topic within Islamic history. You are correct in saying that Jihad has always existed. It is explicitly mentioned within the Qur'an as both an inner struggle and an outward fight. It is from here that come the terms *Jihad Akbar* (Lit: Greater Jihad) and *Jihad... | [
"Jihad has been used by Shia Islamists in the 20th Century: Ruhollah Khomeini declared jihad on Iraq in the Iran–Iraq War, and the Shia bombers of Western embassies and peacekeeping troops in Lebanon called themselves, \"Islamic Jihad\". Nonetheless it has not had the high-profile or global significance it had amon... |
Hey askscience, can anyone explain this colorful cloud formation? | It's pretty simple actually... just ice crystals acting like tiny prisms, splitting the light from the sun into components and spreading out.
The angle from sun to cloud to you is important, but essentially all that is needed is an icy cloud and sunlight. You just happened to be at the right angle at the right time.
... | [
"A pileus (; Latin for \"cap\"), also called scarf cloud or cap cloud, is a small, horizontal, lenticular cloud appearing above a cumulus or cumulonimbus cloud. Pileus clouds are often short-lived, with the main cloud beneath them rising through convection to absorb them. They are formed by strong updraft at lower ... |
why does the military insist on saluting? | Saluting has a long history that is actually not written in stone. However one explanation is that it was originally used as a greeting between two knights to show their face and thus not be seen as an enemy. Additionally it would take away from their master hand to hold their weapon.
This has progressed through to wh... | [
"Article 30 states that, when in the flag is being marched or paraded (for example, when the national anthem is being played), everyone present must take a respectful attitude, standing in silence. Males must remove any head coverings. Military personnel must salute or present arms according to their corps' interna... |
Do emotions effect how long the brain can remember a certain event? If so, are positive or negative events easier for the brain to remember? | Definitely! There is actually quite a large literature on the topic of emotional memory. There are several mechanisms through which emotions might produce more lasting memories: greater attention during the event, more elaboration after the event, improved consolidation of the trace. Fear conditioning, although not mem... | [
"The lack of remembered detail especially affects positive memories; generally people remember positive events with more detail than negative events, but the reverse is seen in those with depression. Negative memories will seem more complex and the time of occurrence will be more easily remembered than positive and... |
Does soap/detergent "clean" or does it just lower the surface tension of water? | Detergents are a type of molecule that is amphiphilic, meaning it is partly hydrophilic (water seeking and polar) and partly hydrophobic (water repelling and non-polar). This allows polar and non-polar substances like oil and water to mix. From a practical standpoint, using detergent in water just allows that mixture t... | [
"Lime soaps build deposits on fibres, washing machines, and sinks. Synthetic surfactants are less susceptible to the effects of hard water. Most detergents contain builders that prevent the formation of lime soaps.\n",
"Some bath salts such as phosphates have a detergent action that softens calloused skin and aid... |
Is the old adage 'it's not the volts that hurt you, its the amps' true? | yes, amps are what kill you. BUT... you need a high voltage for the current to overcome the resistance of your skin.
you can touch both terminals of a car battery and not get shocked because its only 12 volts.
also be aware that even current less than one amp is enough to kill you if it pass through your heart | [
"The ampere ( or (UK), symbol: A), often shortened to \"amp\", is the base unit of electric current in the International System of Units (SI). It is named after André-Marie Ampère (1775–1836), French mathematician and physicist, considered the father of electrodynamics.\n",
"According to the Princeton Encyclopedi... |
how in the world hand dryers are more efficient than 1 or two paper towels when considering the costs of electricity, time, and frustrations. plus the mechanical cost and upkeep involved. | The big cost is maintenance. Paper towels run out. A hand dryer will last years. You can buy a hand dryer for about $100 and it cost pennies to run for electricity. Electricity you already need to buy so additional cost are hardly noticeable. A $100 of paper towels might last a week, a month maybe? Then you need to buy... | [
"Due to the reduction in litter and waste in comparison with paper towels, which cannot be recycled, hand dryers are claimed to be better for the environment. Another study shows that whereas the majority of the environmental impact of a hand dryer occurs during its use, the environmental impact of paper towels is ... |
is a strong metabolism a product of genetic makeup or lifestyle choices as a child? | It is both. Metabolism is primarily the product of genetics, but your lifestyle will affect it to varying degrees. The more active you are the faster/more efficient it will be, but if you are more sedentary it will be slower. | [
"The thrifty phenotype hypothesis proposes that a low availability of nutrients during the prenatal stage followed by an improvement in nutritional availability in early childhood causes an increase risk of metabolic disorders, including Type II diabetes, as a result of permanent changes in the metabolic processing... |
why old bread gets crunchy and old chips get chewy? | The staleness in bread is affectting the gluten (bread structure), the molecules get stiff and harder
Chips because they are fried start crunch and if left in a sealed and dry container will stay crunchy for a longtime. When exposed to air and moisture the crunch that happens from starches caramelize and browning in t... | [
"Chewy and sticky foods (such as candy, cookies, potato chips, and crackers) tend to adhere to teeth longer. However, dried fruits such as raisins and fresh fruit such as apples and bananas disappear from the mouth quickly, and do not appear to be a risk factor. Consumers are not good at guessing which foods stick ... |
what exactly is doxing? | it refers to exposing someone's real life identity, as in finding the *documentation*. | [
"\"Doxing\" is a neologism that has evolved over its brief history. It comes from a spelling alteration of the abbreviation \"docs\" (for \"documents\") and refers to \"compiling and releasing a dossier of personal information on someone\". Essentially, doxing is revealing and publicizing records of an individual, ... |
Do bugs and insects have allergies like humans and other animals? | I'm not an expert in immunology but my work touches on it. Allergies are caused by the immune system overreacting to something that's not a serious threat. The immune system can be thought of as comprising two parts, the innate and the adaptive. The [innate immune system](_URL_1_) is the more simple and older part. All... | [
"After considering the various suspected agents, Portaels \"et al.\" proposed the hypothesis that human beings, as well as domestic and wild animals, could be contaminated or infected by biting insects such as water bugs. Aquatic bugs are cosmopolite insects found throughout temperate and tropical regions especiall... |
what's up with this "score hidden" nonsense on reddit? | Guessing it's so that people up/downvote based on the content of the comment and not just due to current comment score. | [
"In the 2009 book \"Dirty rotten strategies\" by Ian I. Mitroff and Abraham Silvers described type III and type IV errors providing many examples of both developing good answers to the wrong questions (III) and deliberately selecting the wrong questions for intensive and skilled investigation (IV). Most of the exam... |
What would happen if the Earth was thrown from orbit? | We'd have to go out for [pails of air](_URL_0_). | [
"Accidents can occur on the ground during launch, preparation, or in flight, due to equipment malfunction or the naturally hostile environment of space itself. An additional risk is posed by (unmanned) low-orbiting satellites whose orbits eventually decay due to friction with the extremely thin atmosphere. If they ... |
how does a missile break through a meter of concrete? | If you mean bunker buster missiles it's mostly the weight and kinetic energy. Since they use dense explosives and heavy hardened cases when they get up to speed with rocket motor assistance they just punch through stuff.
Some where even made from artillery barrels
_URL_0_ | [
"BULLET::::- Compression barriers – This idea is to place cushioning materials, such as tires, water barrels, or sand barrels, against the concrete wall, and then cover those cushions with a smooth surface that would give when impacted, and then pop back out to its previous shape once the impact is over.\n",
"BUL... |
how are plastic 'micro' particles in our water cleaned up if they can't break down naturally? | There is newly discovered bacteria that can help to decompose plastic. No one is totally sure when this evolution started happening but it's here.
_URL_0_ | [
"The patch is one of several oceanic regions where researchers have studied the effects and impact of plastic photodegradation in the neustonic layer of water. Unlike organic debris, which biodegrades, plastic disintegrates into ever smaller pieces while remaining a polymer (without changing chemically). This proce... |
What is the most abundant element in the world? | The atmosphere is more than three quarters nitrogen, although the atmosphere makes up the thinnest of veneers around the planet and mass-wise is paltry compared to that of the solid Earth.
In terms of the [solid Earth](_URL_2_), although there is plenty of iron in the inner and outer cores, the mantle is the most vo... | [
"The abundance of the chemical elements on Earth varies from air to crust to ocean, and in various types of life. The abundance of elements in Earth's crust differs from that in the Solar system (as seen in the Sun and heavy planets like Jupiter) mainly in selective loss of the very lightest elements (hydrogen and ... |
why does everyone make ham on easter? | Well in sweden we eat herring on easter. As we do on every big Jesus thing. | [
"Ham is a traditional Australian dish that features on most tables on Christmas Day. It is cooked and served in many ways all around Australia, with many families adding their own secrets to the ham, making it a special aspect of a Christmas lunch or dinner. \n",
"In the United States, an Easter tradition involve... |
What was the role of the United Kingdom in the Nuremberg Trials post world war 2? | Well, the UK was part of the four Allied judges and prosecution for the International Military Tribunal (IMT). Geoffrey Lawrence was the main British judge at the IMT and President of the tribunal. Hartley Shawcross was the UK's prosecutor for the IMT and worked in conjunction with the other prosecutors for the IMTs.... | [
"After the end of World War II, the Nuremberg trials were conducted in 1945 and 1946 to bring Nazi war criminals to justice. The Nuremberg Charter, decreeing an International Military Tribunal (IMT), was announced on 8 August 1945 to conduct 13 trials made up of judges from the United States, Great Britain, France ... |
Did the wealthy ancient Greeks (the ancient Greeks of around Socrates's time) hunt lions for pleasure? | Possibly; but (a) they would have had to go to Thrace to do so, and (b) it's very unclear how many lions were still around at that time. Lions are frequently used in poetic imagery in Homer and other Classical-era poetry, but that doesn't imply that they were still around all over the place: it's likely that the popula... | [
"Lions were present in the Greek peninsula until classical times; the prestige of lion hunting was shown in Heracles' first labour, the killing of the Nemean lion, and lions were depicted as prominent symbols of royalty, as for example in the Lion Gate to the citadel of Mycenae.\n",
"Several discoveries of lion b... |
How do energetically excited atoms give off light? | > How does this decay process actually happen, and why does an electron decaying to a lower-energy state produce an electromagnetic wave?
The atom plus electromagnetic field is described by a quantum state vector, and the state vector evolves with time according to quantum mechanics.
Electrons have electric charge, ... | [
"Atoms emit and absorb light at characteristic energies. This produces \"emission lines\" in the spectrum of each atom. Emission can be spontaneous, as in light-emitting diodes, gas discharge lamps (such as neon lamps and neon signs, mercury-vapor lamps, etc.), and flames (light from the hot gas itself—so, for exam... |
Can something escape the particle horizon? If not, would that essentially make the observable universe a black hole of sorts? | Once a region of spacetime has entered our particle horizon, it's there to stay. It cannot go back behind it. (However, objects that enter the particle horizon later are increasingly redshifted.)
This is not like a black hole because the particle horizon is different for each point of space. There are objects that wil... | [
"An observer crossing the event horizon of a non-rotating and uncharged (or Schwarzschild) black hole cannot avoid the central singularity, which lies in the future world line of everything within the horizon. Thus one cannot avoid spaghettification by the tidal forces of the central singularity.\n",
"The black h... |
Is it possible that the Bohr Model of the atom is just a convenient way to visualize the phenomenon we observe and real atoms are nothing like what we think? | Well, it's well known that the Bohr model isn't an accurate representation of how atoms work—it's just an approximation to our current quantum mechanical models. As for whether our actual current models describe what's "really" going on, that's more a matter for philosophy (in fact, our models don't even claim to tell ... | [
"The Bohr model explains the atomic spectrum of hydrogen (see hydrogen spectral series) as well as various other atoms and ions. It is not perfectly accurate, but is a remarkably good approximation in many cases, and historically played an important role in the development of quantum mechanics. The Bohr model posit... |
i have heard that beer changed the world. but i would like to know how and why. | Beer provided an easy way to make safe drinks (that provide calories as a bonus), in a world where most water was teeming with microorganisms that could be lethal or sickening. By fermenting, alcohol kills off most of the bacteria. | [
"How Beer Saved the World is an hour-long documentary that was broadcast on the Discovery Channel on January 30, 2011. Produced by Australian production company Beyond Productions, the documentary takes a look at the origins of beer and how it has had an influence on major events in human history such as the buildi... |
how the first living microorganisms came to be. | Stephen Hawking did a BRILLIANT documentary to explain simply and with pictures/animation and metaphores the whole lot.
I THINK it was 'Into the Universe with Stephen Hawking' but am not 100%
It explains how the primordial soup contained the ingredients to begin speciic types of life and then what happened once life w... | [
"Microorganisms are the earliest form of life on earth, first evolving more than three billion years ago. Our ancestors discovered how to harness the power of microorganisms to make new foods, even if they did not know the science behind what they were doing.\n",
"Single-celled microorganisms were the first forms... |
Why do seagulls 'dance' when looking for grub? | As Zaggynl suggests, the acoustic effect of the paddling is what's causing the worms to come to the surface - and it's not just gulls who do it. People do it as well, drumming the soil to collect worms for bait (called 'grunting'!).
However, the reason the worms come up isn't quite clear. Again as zaggynl points out o... | [
"Lemmings measure around in length and weigh around . Lemmings are quite rounded in shape, with brown and black, long, soft fur. They have a very short tail, a stubby, hairy snout, short legs, and small ears. They have a flattened claw on the first digit of their front feet, which helps them to dig in the snow. The... |
here we have 'millionaires,' what are other countries' (non-us) division markers for wealth? | "ELI5 is for requests for easy-to-follow explanations of complex concepts and subjects. That means no questions that are just looking for straightforward answers, that are subjective, a request for a guide/walkthrough, or that are objective but not asking for an explanation of an answer. ELI5 is absolutely not a reposi... | [
"BULLET::::- As of May 2005, the 125 richest people in the world have assets that exceed the annual combined GDP of all the least developed countries (calculation based on data from list of countries by GDP (PPP) and list of billionaires).\n",
"A total of 1,011 people made the 2010 list. The United States account... |
Why do we know so much more about Celtic and Norse mythology than Baltic or Slavic mythology? | /u/LoveSomeLove provides an important caveat, that many of the details of Norse mythology are foggy. This is even more true of Celtic mythology, because we don't actually know very much about it. We have legendary and heroic stories, particularly of Ireland and to a lesser extent Wales and Scotland, but doing something... | [
"Norse mythology has been the subject of scholarly discourse since the 17th century, when key texts were brought to the attention of the intellectual circles of Europe. By way of comparative mythology and historical linguistics, scholars have identified elements of Germanic mythology reaching as far back as Proto-I... |
What is observation? | [Searched](_URL_3_)
Relevant [discussion](_URL_1_)
Original comment by [Burdybot](_URL_2_)
> My friend and I are currently arguing over this concept. He says that an observer requires consciousness to determine the state of a system according to quantum superposition. I say that an observer does not have to be a li... | [
"Observation is the active acquisition of information from a primary source. In living beings, observation employs the senses. In science, observation can also involve the perception and recording of data via the use of scientific instruments. The term may also refer to any data collected during the scientific acti... |
When global mean sea level rises by one inch, how are various local high tide levels affected? | Local sea level is changing differently than the global average - depending on where you are. (For example see this map [here](_URL_0_)) This variation is due to local temperature/salinity changes, shifting currents and rising or sinking land (due to subsidence, earthquakes etc.).
Tides are essentially shifted up or d... | [
"The Intergovernmental Panel on Climate Change (IPCC) estimate global mean sea-level rise from 1990 to 2100 to be between nine and eighty eight centimetres. It is also predicted that with climate change there will be an increase in the intensity and frequency of storm events such as hurricanes. This suggests that c... |
How do you determine the epicenter of an earthquake... | By using a network of seismographs around the world, scientists are able to employ a triangulation method which pinpoints the source of the slippage event (earthquake) by measuring the s and p waves that are generated by it.
Basically, it would be very difficult, if not impossible to determine the origin of an earthqu... | [
"The location of an earthquake (its epicenter and depth) needs to be known rapidly for estimating losses. It is calculated from the times at which the waves it generates arrive at seismographs surrounding the source. A computer moves the epicenter estimate close to those stations which record the waves first and fa... |
if i were to broadcast on a frequency used to broadcast a radio station, would people tuning into that station hear static due to the interference between the two? | It depends on whose signal is stronger.
If you put a radio right next to your broadcasting antenna, it'd probably pick up only your broadcast because it'd be a lot stronger.
If you put a radio far away from your antenna, such that your broadcast was comparatively weak, then they'd pick up the "main" radio station at ... | [
"BULLET::::- Some digitally-tuned FM radios are unable to tune using 50 kHz or even 100 kHz increments. Therefore, when traveling abroad, stations that broadcast on certain frequencies using such increments may not be heard clearly. This problem will not affect reception on an analog-tuned radio.\n",
"In analog r... |
how does my charger know to stop charging my phone when it's at 100%? | The usual way the state of charge for any battery is measured is by voltage. It's most accurate when the battery is full or nearly full or empty.
My guess would be that there's a target voltage and when it's reached the cellphone disconnects the charger electronically.
Proper battery monitors actually use a more comp... | [
"If a battery has been completely discharged (e.g. the car lights were left on overnight) and next is given a fast charge for only a few minutes, then during the short charging time it develops only a charge near the interface. The battery voltage may rise to be close to the charger voltage so that the charging cur... |
how does healing bleeding work inside the mouth (wet environment) compared to the bleeding of the skin? | It acts the same way. Your Blood vessel lining contains special enzymes which, when in contact with your blood starts what we call primary hemostasis, which activates the platelets to connect and block the biggest amount of blood from escaping before the nearby Proteins and enzymes nearby are activated to form a fibrin... | [
"Wound cleansing forms an integral part of wound management and generally suggests the application of a fluid to aid the removal of surface contaminants, bacteria and debris from the wound surface and surrounding skin. Water as a cleansing agent, especially in chronic wounds has been proposed and is widely used esp... |
How did someone go about buying a house in medieval times? | Well as the other answers and deleted answers have already implied, it’s a bit difficult to say because the question is extremely broad. The answer would change depending on where and when you are (as it would today as well - buying a house can be vastly different even within one country).
First of all, the idea that ... | [
"The , a 13th-century house, keeps a medieval aspect despite the restorations of the 19th century. It probably, belonged originally to a rich clothier. The ground floor was devoted to artisanal production and trade, while the floors sheltered the housing of the craftsman.\n",
"In Medieval days a destination for s... |
Do undersea creatures experience any sort of weather? | Yes. Visibility under water changes constantly (comparable to "under water storms"), different algae bloom at different times a year - changing the eco system, water currents change temperature and oxygen levels. You can find "dead water" below water, which could be compared to - lets say deserts? The marine life is ju... | [
"Alien creatures which are rarely seen rise out of the deep ocean waters to visit the warmer waters of the reef. Weather systems also play a part with cyclones posing a great danger to animals and the reef alike.\n",
"The oceans depths and temperatures contains some of the most extreme conditions for any species ... |
In what ways did the post-WWII “baby boom” affect the “crime wave “of the 1960s and 1970s - especially in the context of so many young, (disproportionately) black men coming of age in impoverished, segregated urban centers that had experienced massive white flight? | It seems like you are asking for the connection between the baby boom and crime in black neighborhoods in the 60's and 70's, but I think your question is assuming the answer. History is not so easy to draw a line through, but there are some important factors that contributed to crime in black communities in the 60's an... | [
"The urban crisis of the 1960s continued to escalate in the 1970s, with major episodes of riots in many cities every summer. The postwar suburbanization boom had left America's inner cities neglected, as middle-class whites gradually moved out. Rundown housing was increasingly filled by an underclass, with high une... |
some bees have developed a way to kill hornets. they cook them. how can such a complicated behavior evolve? | It's not that hard to figure out really. They want to attack the wasp, but they can't because the stinger isn't thick enough. They don't know this, so they attack all the same. Bees naturally swarm predators, so tons of bees attack one wasp at the same time. Had they been able to sting it to death, they would stop,... | [
"The best place for hornets to find a combination of animal proteins (bees or larvae) and carbohydrates (honey) are bee hives. Oriental hornets have been known to cause serious damage to bee colonies. They are the primary pest that attacks honey bee colonies in many countries. In defense, Japanese honey bees have b... |
Religious history question, specifically Jewish history | You seem to have thought this question out pretty well, without reading a book about Judaism or anything...
_URL_2_
_URL_1_
_URL_0_
Going to the library and picking up an English translation of the Talmud will teach you more about this than I ever could by writing a comment. Seriously, it looks esoteric, but it's e... | [
"Jewish history is the history of the Jews, and their religion and culture, as it developed and interacted with other peoples, religions and cultures. Although Judaism as a religion first appears in Greek records during the Hellenistic period (323 BCE – 31 BCE) and the earliest mention of Israel is inscribed on the... |
Does aphantasia affect people's ability to dream? | From the [Wikipedia article](_URL_0_) on Aphantasia, describing a study published in 2015 by Professor Adam Zeman:
“In the same paper, it was identified that aphantasia characterizes only voluntary visualizations; the aphantasiacs were still able to have involuntary visualizations (i.e. dreams)”
So it seems there is ... | [
"Some supplemental melatonin users report an increase in vivid dreaming. Extremely high doses of melatonin increased REM sleep time and dream activity in people both with and without narcolepsy. Some evidence supports an antidepressant effect.\n",
"The alleviation of dysphoria theory suggests that people with sev... |
when i get driving directions from google maps, the estimated time is usually fairly accurate. however, i tend to drive much faster than the speed limit. does google maps just assume that everyone speeds? how do they make their time estimates? | Driving faster does not really result in a large time savings. You would be surprised how little time you actually save by going 80 instead of 65, especially for shorter trips. Slow the fuck down. | [
"For any tiny interval of time in the car, you could calculate how far the car has traveled in that interval by multiplying the current speed of the car times the length of that tiny interval of time. (This is because \"distance\" = \"speed\" formula_8 \"time\".)\n",
"GPS time is expressed with a resolution of 1.... |
Did team sports originate in the Americas? | No. The Greeks and the Romans played Episkuros or Harpastum (which seems to be the ancestor of Rugby and Association Football.) The Chinese played Cuju, or Tsu Chu a game much like Association Football. The Iranians, Indians and Afghans all played a game like Polo.
_URL_0_
Harris, H.A. Sport in Greece and Rome. Lon... | [
"Professional sports leagues as known today evolved during the decades between the Civil War and World War II, when the railroad was the main means of intercity transportation. As a result, virtually all major league teams were concentrated in the northeastern quarter of the United States, within roughly the radius... |
what is the science behind muscle fasciculations or “muscle spasms”? | Nerve tells muscle to contract. Muscle needs a supply of free-floating energy (called ATP) for it to relax again.
Your body’s metabolism is a system of checks and balances where the big players are oxygen, carbon dioxide, ATP, sodium, and potassium. If this is disrupted (for any number of reasons) and the muscle does... | [
"Work at the Institute for Cell Biology, University of Bonn, showed that a certain type of autophagy, i.e. chaperone-assisted selective autophagy (CASA), is induced in contracting muscles and is required for maintaining the muscle sarcomere under mechanical tension. The CASA chaperone complex recognizes mechanicall... |
is anti-gravity possible? | Isaac Asimov wrote a short story about a scientist who made a theorem on reducing mass (i.e the operative factor in how gravity affects objects), and an inventor's attempts at turning it into a reality.
I won't spoil the ending for you, but the problem is that the only particles in the universe that have no mass are t... | [
"\"Anti-gravity\" is often used to refer to devices that look as if they reverse gravity even though they operate through other means, such as lifters, which fly in the air by moving air with electromagnetic fields.\n",
"There have been a number of attempts to build anti-gravity devices, and a small number of rep... |
Why is my urine so deep yellow after I wake up in the morning? | Your body secretes anti-diuretics while you sleep, so very concentrated urine first thing in the morning is normal. | [
"In case the urine looks in pink, red, or lighter brown is generally caused by beets, blackberries, certain food colorings, hemolytic anemia, renal impairment, urinary tract infection, medication, porphyria, intra-abdominal bleeding, vaginal bleeding, neoplasm located in either bladder or kidneys pathways.\n",
"M... |
what (possible) consequences can occur if a baby is born later then it should? in terms of development of the body, the mind, etc. | The main concern is that the placenta, the sack surrounding the baby, will no longer be able to supply the baby with food, blood, and oxygen. Complications aren't generally expected though and if necessary the baby can always be delivered when a doctor sees fit.
Source; EMT in Paramedic school. | [
"Stress and trauma experienced as a baby in the womb will turn into a normal expectation when born. As Freud has identified, infant development is affected severely by negative limbic imprints on the brain because at this stage the \"Ego\" is vulnerable and susceptible adverse effects. This is in part due to an inf... |
Can tattooed skin be used for a skin graft? | Most skin grafts though are between one site on a person's body and another site, not between two different people. Because if you graft between two people, you have to worry about rejection and have a matching donor. | [
"Skin grafting is patching of a defect with skin that is removed from another site in the body. The skin graft is sutured to the edges of the defect, and a bolster dressing is placed atop the graft for seven to ten days, to immobilize the graft as it heals in place. There are two forms of skin grafting: split thick... |
is there actually any significant difference in the chemical composition of household cleaners which claim to be for the "kitchen" or "bathroom", or are they all basically the same thing? | Not in their chemical composition but in their physical composition. Bathroom usually means ceramic tile and porcelain and kitchen usually means linoleum, stainless steel, and veneer cabinetry.
Ceramics are hard. In fact they are some of the hardest materials found in most homes short of glass, silica, or diamond. So... | [
"The cleaning industry is quite big as different types of cleaning are required for different objects and different properties. For example, cleaning an office space requires the services of a commercial cleaner whereas cleaning a house requires domestic cleaning services. Depending on the task, even these categori... |
how can "no gender roles" and "transgender" exist at the same time? | Bluntly speaking, one does not have to have gender roles to feel uncomfortable in a particular body. | [
"Transgender people experience a mismatch between their gender identity and their assigned sex. \"Transgender\" is also an umbrella term because, in addition to including trans men and trans women whose binary gender identity is the opposite of their assigned sex (and who are sometimes specifically termed \"transse... |
Why are American government officials secretaries but European government officials are ministers? | Actually, the term "secretary" is used for offices in the United Kingdom as well: Secretary of State, Home Secretary, Chief Secretary, and so on.
The word comes from the Latin *secretarius*, literally meaning a person entrusted with a secret, or a confidential officer. The term was first used as a title for ministers ... | [
"In the Australian government, Secretaries are the responsible officers for departments, meaning that they are answerable to the Australian Parliament for ensuring that the department performs the functions assigned to it and spends money appropriately, as granted by the Parliament. Secretaries are frequently calle... |
Why does yellow exist on the light spectrum but not pink? | To understand, look at [the color response curve of the 3 types of cones we have in our eyes](_URL_0_). The x-axis is the wavelength of light going into the eye, and the y-axis is how strongly the cone "fires" based on that wavelength. Their peak response roughly correlates to blue, green and red, which is why we call ... | [
"Yellow is the color of light with wavelengths predominately in the range of roughly 570–580 nm. In the HSV color space, it has a hue of around 60°. It is considered one of the subtractive primary colors.\n",
"Yellow is the color between orange and green on the spectrum of visible light. It is evoked by light wit... |
siamese twins criminal | The proper term is "Conjoined Twin" and the answer is no one knows. It has never happened and until does happen there is no need to figure out how to rule on it.
In all likelihood they would be let go, in the US at least. The 14th Amendment prohibits the punishment of innocent people, while the 5th amendment guarantee... | [
"Chang and Eng Bunker (1811–1874), Thai brothers born in Siam, now Thailand, traveled widely for many years and were labeled as the Siamese twins. Chang and Eng were joined at the torso by a band of flesh, cartilage, and their fused livers. In modern times, they could have been easily separated. Due to the brothers... |
If light is not absorbed by space, why are stars which are far away are less bright than the ones which are close to earth? (assuming they emit similar intensity of light per second) | As the light travels from the star, it gets spread out of a greater and greater area, and thus the farther away the star is, the less of its light hits the Earth. | [
"The light from stars (other than the Sun) arrives at Earth precisely collimated, because stars are so far away they present no detectable angular size. However, due to refraction and turbulence in the Earth's atmosphere, starlight arrives slightly uncollimated at the ground with an apparent angular diameter of abo... |
How does leather tanning work? Can you apply similar methods to something like, banana skins? | No, tanning happens due to the formation of complexes which cross-link the collagen fibers, both strengthening them and making them more difficult to break down(for example, by microbes). Fruit skins are made primarily out of cellulose; the process that will "polymerize" collagen fibers won't do the same to them.
You... | [
"Tanning is the process that converts the protein of the raw hide or skin into a stable material which will not putrefy and is suitable for a wide variety of end applications. The principal difference between raw hides and tanned hides is that raw hides dry out to form a hard inflexible material that can putrefy wh... |
What was the average age of a British person attending college in the 17th century? | Attending Oxford or Cambridge at 13 was not unusual - there was no minimum age at which you could enrol, although younger than 13 would have been uncommon. And of course, you had to be male - women could not take degrees in Britain until the mid-19th century.
The diarist and civil servant Samuel Pepys didn't enrol at ... | [
"In 2000 there were 14,216 students, with the youngest in their early teens and the oldest in their late 80s. There is often a span of 60 years between the oldest and youngest students, and students as young as 11 years old have taken courses alongside those old enough to be their parents or grandparents. Of the st... |
why does natural peanut butter (no sugar or oil) still taste sweeter than raw peanuts | Although the starch molecule is a chain of hundreds of glucose molecules, it doesn't activate your sweetness taste receptors like individual glucose can.
The beginning of your digestive tract is not the stomach, but the mouth. Like your stomach, your saliva contains enzymes (amylase) which break down complex carbohyd... | [
"Peanut butter's flavor combines well with other flavors, such as oatmeal, cheese, cured meats, savory sauces, and various types of breads and crackers. The creamy or crunchy, fatty, salty taste pairs very well with complementary soft and sweet ingredients like fruit preserves, bananas, apples, and honey. The taste... |
if jury nullification is a legal instrument to the american legal system, why judges penalize anyone who attempts to present a nullification argument to jurors? | Jury nullification isn't an intentional part of the legal system; it's an unavoidable consequence of crucial parts. If you can't punish the jury for its decision (which is crucial) and the decision is by the jury (also, for us, crucial), jury nullification just sort of appears and can't be gotten rid of. We didn't writ... | [
"In the 1895 case of \"Sparf v. United States\" written by Justice John Marshall Harlan, the United States Supreme Court held 5 to 4 that a trial judge has no responsibility to inform the jury of the right to nullify laws. This decision, often cited, has led to a common practice by United States judges to penalize ... |
how do consulting/advisory firms work? | The big four firms have the ability to bring in insight from other banks that her firm may not be privy to. She and her colleagues spend their time running a bank, not thinking about what comes next and how to implement it. This is particularly true given that the big 4 often perform the actual implementation of techno... | [
"An independent advisory firm (sometimes less accurately called an advisory boutique) is an investment bank that provides strategic and financial advice to clients primarily including corporations, financial sponsors, and governments. Revenues are typically generated by providing deal-specific advice related to mer... |
how can rain forests have infertile soil yet such huge growth? | Because the trees pull up the nutrients as rapidly as they're deposited, there is no buildup of nutrients in the soil. The nutrient layer is very much in the surface, there's very little underneath. The trees are living on recycled nutrients of all the trees around them. The same matter goes around and around the cycle... | [
"Scientists originally thought that the heavy vegetation of tropical rain forests would provide rich nutrients, but as rainfall passes through the litter on the forest floor the rain is acidified and leaches minerals from the above soil layers. This forces plants to get their nutrition from decaying litter as Oxiso... |
”why do goggles allow us to see underwater even though when the water itself is clear?” | Water makes light bend differently than the air around you. This property is called the "refractive index," and it affects how light bends. You know how, when you look at a straw in a glass of water, it appears to "break" at the surface? That's because of the difference in refractive index between air and water.
When ... | [
"Water has a higher refractive index than air – similar to that of the cornea of the eye. Light entering the cornea from water is hardly refracted at all, leaving only the eye's crystalline lens to focus light. This leads to very severe hypermetropia. People with severe myopia, therefore, can see better underwater ... |
why is the heat in horseradish different from the heat in a chilly pepper? | The heat is caused by different chemicals. In horseradish, it gets hot when the root is ground up and releases oils called isothiocyanates, depending on the desired heat, vinegar is added immediately to stabilize the reaction for milder horseradish, or later for spicier. Horseradish causes its "spicy" sensation by irri... | [
"While poblanos tend to have a mild flavor, occasionally and unpredictably they can have significant heat. Different peppers from the same plant have been reported to vary substantially in heat intensity. The ripened red poblano is significantly hotter and more flavorful than the less ripe, green poblano.\n",
"Co... |
Can accelerating spacetime expansion eventually rip apart a black hole? | Let me stop you right here: there is an *exact* solution to the Einstein field equations describing a black hole in exponentially expanding spacetime (just like our near future) and it is the [de Sitter-Schwarzschild metric](_URL_0_), and nothing happens to the black hole. It's perfectly fine.
Also the force due to da... | [
"As predicted by general relativity, the presence of a mass deforms spacetime in such a way that the paths taken by particles bend towards the mass. At the event horizon of a black hole, this deformation becomes so strong that there are no paths that lead away from the black hole.\n",
"Initially, the explanation ... |
how does the rotten tomato rating system work? | % of critics on the website that like the movie.
Audience score is the same, but with movie goers over Pro Critics.
Don't use the Tomato rating as a "how good" the movie is, it's meant to be more of the % chance you'll like the movie. Theres some low 40% movies I really enjoy, and some upper 90% ones I don't. Its a s... | [
"\"Rotten Tomatoes\" is an American review-aggregation website for film and television. The name \"Rotten Tomatoes\" derives from the practice of audiences throwing rotten tomatoes when disapproving of a poor stage performance. \"Rotten Tomatoes\" took the tomato metaphor further by rating films as \"Certified Fres... |
why are old iphones so much slower? | Newer versions of iOS require more processing and more ram to maintain the same usability.
New versions of iOS are designed to make the latest generation look flashy, last gen look aging and older phones unusable to encourage people to buy the latest phone.
Otherwise apple would go out of business. | [
"In December 2017, there were reports that Apple has been using a policy of slowing down the speed of its older iPhones when issuing operating system upgrades. It has spurred allegations that the firm has been using this as a tactic to prompt users of older iPhones to buy newer models.\n",
"Apple said in December... |
why would an electric company such as nrg buy the naming rights to a stadium? what's the benefit for them? | The name of the stadium is mentioned in ads for events. Better for a product like Minute Maid - IMO . Reminds consumers that they are a big deal. Ultimately, their board probably gets a lux suite to entertain in. | [
"Occasionally, the purchaser of a stadium's naming rights may choose to donate those rights to an outside organization, typically one to which it is closely related. Probably the most notable example of this is Friends Arena, a major stadium in Stockholm. The facility was originally known as Swedbank Arena, but in ... |
Why can nature generally be modeled well with whole number exponents? | It is difficult to answer this question in the most general sense.
Things that follow an inverse-square law, like gravity and electromagnetism usually do so due to space being 3-dimensional and the surface area of a sphere being O( r^2 ). | [
"Edward Nelson criticized the classical conception of natural numbers because of the circularity of its definition. In classical mathematics the natural numbers are defined as 0 and numbers obtained by the iterative applications of the successor function to 0. But the concept of natural number is already assumed fo... |
Do accelerators other than the LHC actively do particle physics research? | Yes, quite a few. Just off the top of my head: TRIUMPH, RHIC, GlueX, Belle2. | [
"The experience from the operation of LEP and LHC and the opportunity to test novel technologies in the High Luminosity LHC provide a basis for assessing the feasibility of a post-LHC particle accelerator. The study delivered a Conceptual Design Report (CDR) by the end of 2018, in time for the next European Strateg... |
What happened to the Middle East? | For start, many Middle Eastern nations were more secular and westernized, but it isn't like those views were found universally amongst the residents of those nations. There were definitely conservatives, they just generally weren't in any positions of power and often weren't even in the main cities. Terrorist groups as... | [
"Following a meeting of Arab League foreign ministers in Cairo on 16 July, Secretary-General Amr Moussa declared that \"The Middle East process is dead\" and that \"The only way to revive the peace process is to take it back to the\n",
"This timeline tries to compile dates of important historical events that happ... |
what are those "puddles of sunlight" you see when driving, and how do they work? | If you are referring to this illusion that the road is somewhat wet in the distance, it is a phenomenon you know as a 'mirage'. The layer of air that is close to the ground is hotter than the air above because the road warms it. And hot air is harder for light to go through; therefore light rays are not straight when t... | [
"Puddles commonly form during rain, and can cause problems for transport. Due to the angle of the road, puddles tend to be forced by gravity to gather on the edges of the road. This can cause splashing as cars drive through the puddles, which causes water to be sprayed onto pedestrians on the pavement. Irresponsibl... |
you have three doors, and behind one is a prize. you pick one door which you think the prize is behind the presenter of the tv show knows which door the prize is behind. he opens one, and the prize is not behind it he now gives you the chance to change doors if you do you get better odds. how? | When you pick the first one there is a 33% chance you picked the right one.
When he eliminates one, it means the unchosen door now has a higher chance of being correct, which is more likely than the first door when you picked it.
It makes sense because no matter which door you pick, a wrong door will be eliminated, s... | [
"As Keith Devlin says (Devlin 2003), \"By opening his door, Monty is saying to the contestant 'There are two doors you did not choose, and the probability that the prize is behind one of them is . I'll help you by using my knowledge of where the prize is to open one of those two doors to show you that it does not h... |
what does the snake on the medicine emblem mean? | [The Caduceus](_URL_2_) is actually a symbol of Hermes, often misused as a medical symbol or mistaken for the [Rod of Asclepius](_URL_1_). The Caduceus was not meant as a symbol of medicine, and as such there isn't meaning behind the snakes as a medical symbol. It was simply misused enough times (documented mistakes by... | [
"The caduceus is the traditional symbol of Hermes and features two snakes winding around an often winged staff. It is often mistakenly used as a symbol of medicine instead of the Rod of Asclepius, especially in the United States. The two-snake caduceus design has ancient and consistent associations with trade, eloq... |
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