id stringlengths 5 6 | input stringlengths 3 301 | output list | meta null |
|---|---|---|---|
546nhb | how does a country surrender? | [
{
"answer": "Surrender is a conversation between the winner and the loser. Either side can theoretically start the conversation (\"I want to give up!\" vs. \"do you want to give up yet?\"). It comes down to the *terms* of surrender - the loser will often have to give up very valuable things to get the winner ... | null |
6d3kzi | how can doctors say someone definitively died from second-hand smoke? | [
{
"answer": "Significant factor!\n\nA doctor must complete a Death Certificate listing 1) immediate cause, 2) underlying cause(s), and 3) Significant factors contributing to death.\n\n1) Immediate cause is almost always some series of Latin words that mean \"heart stopped.\"\n\n2) Underlying cause(s) is what m... | null |
15c9xa | What was life like for the average person in Roman Britain? | [
{
"answer": "The Romans were not particularly harsh rulers (in fact within that statement there are several flawed assumptions), but life certainly did not occur as usual. Britain after the conquest in 54 CE (well, really towards the end of the century) underwent a process that has been termed \"Romanization\".... | null |
32kj9y | How did Italian-Americans fighting for the Allies in WW2 feel about the Italy's support of the Germans? | [
{
"answer": "Also on a related topic, was it common for people with Italian names to \"Americanize\" them? This seems to be fairly common in my area with German names. A common local example would be Young. It is common to see it on old headstones as Jung. ",
"provenance": null
},
{
"answer": null,... | null |
3w72bv | Why is it, that tv shows ripped from places like Japanese television networks for example, and then uploaded to youtube, seem to almost always have a horrible resolution? | [
{
"answer": "The long and short of it is that the video is likely to have been lossily transcoded many times by the time it shows up on YouTube. It's transcoded once when going from the content maker to the TV station, another time at the TV station to convert it to a format suitable for airing, possibly once m... | null |
57e0ic | how do nfc credit cards work? do they store the credit card number? how are card numbers not stolen by people with nfc readers? | [
{
"answer": "Firstly, there are no NFC cards, they are RFID. The distinction comes from power. When using NFC payment on phones, the phone transmits the signal, costing some battery life. On RFID cards, you obviously don't charge them, the card reader actually sends a tiny amount of power to them so they are ab... | null |
1k5rol | What can I realistically learn about history from reading Asterix and Obelix? | [
{
"answer": "I'm a massive fan of the series, and grew up reading the comics in both English and French.\n\nHistorically, you're not going to learn much other than 1) The Romans conquered Gaul, 2) the Celts had Druids, and 3) Caesar had a kid with Cleopatra.\n\nThe real brilliance of the series is not in accura... | null |
3swe0k | How did they replace destroyed planes on WW2 aircraft carriers? | [
{
"answer": "Although practice about replacement aircraft differed between navies, there were several methods for replacing damaged or lost aircraft. The most common method was to keep a number of replacement aircraft in storage on the larger fleet carriers. These aircraft were disassembled and required a numbe... | null |
b27fbm | is it possible to remove cancer through surgery or is it only possible to remove tumors but not cancer? | [
{
"answer": "Tumors are clumps of cancerous cells. \"Cancer\" is generally the ailment of being afflicted by cancerous cells; we can't surgically remove all \"cancer\" from a patient because manipulating individual cells is well beyond the capabilities of any surgeon. Conceptually they are physical objects whic... | null |
10155n | why do we get "sand" in the corners of our eyes when we sleep? and why do we not get it during the day when we're awake? | [
{
"answer": "The \"sand\" is actually dried tears.\n\nThat is, tears are similar to salt water -- liquid with salts in them. Overnight, when the tears at the edges of your eyes dry, the salt is left behind as \"sand\". ",
"provenance": null
},
{
"answer": "To expand on what above said, the reason it... | null |
63wjtn | If an alpha particle is essentially the same as a helium nucleus (two protons, two neutrons), why doesn't a helium atom share the same ionising properties? | [
{
"answer": "Alpha particles are ionizing because they have no electrons and they have high kinetic energies (alpha decay Q-values are around 5 MeV).\n\nBullets don't harm you when they're not shot from a gun.",
"provenance": null
},
{
"answer": "Kinetic energy. An alpha particle travels at high spe... | null |
3gjpkk | How likely is it that the atomic bombings of Hiroshima and Nagasaki prevented a Soviet invasion and occupation of Japan? | [
{
"answer": " > Did the demonstration of atomic weapons prevent a possible occupied red Tokyo?\n\nNo. While obviously strong, the Red Army stood no chance of invading Honshu. Simply put, they didn't have the sealift capabilities to pull it off. \n\nAs the Pacific War drew to a close, the Soviets did invade ... | null |
c35dhi | ; why do commercials say something will be aired live, but they show previews of said live event that hasn’t happened yet? | [
{
"answer": "They often show rehearsals so you have an idea what it will be like, or sometimes just an earlier performance by the same artist.",
"provenance": null
},
{
"answer": null,
"provenance": [
{
"wikipedia_id": "12749659",
"title": "Serial (radio and television)",
... | null |
9addku | what happens to valuations and stock prices in financial markets during weekends and off-hours | [
{
"answer": "In most markets trading is down in those hours, so no trades are made at a different price then the market closed. However, I think buy and sell orders can be placed during off hours, influencing the price when it opens again. ",
"provenance": null
},
{
"answer": null,
"provenance":... | null |
30lwm0 | How long would it take to hard-boil an egg on Mount Everest? | [
{
"answer": "The egg requires heat to be cooked, it doesn't actually boil. Boiling water is a lower temperature when it is at a lower pressure, so the egg would exist in lower temperature water, so it would cook slower or not at all depending on the pressure.",
"provenance": null
},
{
"answer": "The... | null |
my7zh | What would happen if we 'bled' a volcano? Would it release pressure, or would it make things worse? | [
{
"answer": "it would completely depend on the type of volcano that you're trying to 'bleed'. If you're looking at a volcano that has a magma chamber filled with andesites and rhyolites (a very quartz rich magma) (see any of the volcanoes around the Ring of Fire\") then drilling a hole to it would be pointless ... | null |
2182ba | Portuguese - Japaneese Travel routes the 1500 century | [
{
"answer": "Here are some suggestions for you to look up. (I won't answer this in full, since that would mean doing your homework for you.)\n\nPortuguese ship ca 1500-1600: I would look up Galleon or Carrack\n\nPortuguese ships sailed down the western coast of Africa and probably stopped at Luanda, Angola to ... | null |
1f50i2 | Are there medical benefits to running the same distance faster or slower? | [
{
"answer": "This is actually quite a common question. Check out some of the previous threads on this topic:\n\n_URL_0_",
"provenance": null
},
{
"answer": null,
"provenance": [
{
"wikipedia_id": "89285",
"title": "Long-distance running",
"section": "Section::::Phys... | null |
6qpf5k | What are the steps between the mouth and neurons that ingested botulinum toxin takes when it causes botulism in the human body? | [
{
"answer": "[Absorption](_URL_1_)\n\nSource: [Interaction of Botulinum Toxin with the Epithelial Barrier](_URL_3_)\n\n[Intoxication](_URL_0_)\n\nSource: [Botulinum Neurotoxins: Biology, Pharmacology, and Toxicology](_URL_2_)\n\nI can answer any specific questions you might have.",
"provenance": null
},
... | null |
18v1bf | What's the stronger protecting layer, Corning "Gorilla" glass from smartphones or sapphire crystal used in watches? Why doesn't one use the other? | [
{
"answer": "They're strong in different ways. Sapphire is super-strong, but brittle. Compared to that, Gorilla glass is flexible.\n\nFor a large display that is likely to get dropped, you want flexibility. If the glass doesn't bend, it'll shatter. It's why modern phones are so much more durable than old PDAs.\... | null |
4ol6hh | Is it true that Iranians knew very little about Persian and Achaemenid antiquity until European historians rediscovered it? | [
{
"answer": "It depends a bit on what you mean, so the Achaemenid Persians appear in Tabari's *History of the Prophets and Kings*, the problem is that to my knowledge neither he nor any successive writer in Persian or in Arabic had access to Herodotus, which remains one of the main sources about the history of ... | null |
1952wb | Why do microwaves damage circuitry? | [
{
"answer": "Microwaves, or any light for that matter, are oscillating EM fields. In the case of MW its on the same size order of most of these objects so the fields couple very well.\n\nThese fields then induce a current which then proceeds to short or melt various parts of circuits.",
"provenance": null
... | null |
dl0vxb | why are not all electromagnetic waves visible to the human eye? | [
{
"answer": "The EM receptors that evolved on Earth are able to see a part of the EM spectrum on Earth. Some creatures have more or less receptors and can see more/less than humans but this is a common theme with evolved traits. Either a mutation to see more never occurred or it did occur but wasn't useful enou... | null |
4havxk | how is digital music (such as techno, electro, etc.) made? what makes up the sounds that they use? | [
{
"answer": "A lot is from digital instruments, whether those are MIDI instruments (you play and then the data goes to a computer where the notes are reproduced with software) or programs that can recreate certain instruments digitally. There are also massive databases (gigabytes and gigabytes) of sounds, melod... | null |
3s4rnd | i suck at math, why is this comic funny? alternatively, if it's not funny, what the hell does it mean? | [
{
"answer": "The first line is [Euler's identity](_URL_1_). It's a formula that involves the numbers e, pi, and the imaginary number i (the square root of 1).\n\nFrom there the artist butchers the math, replacing \"Pi\" with \"P x i\" (in math, the multiplication symbol can often be often omitted, so Pi is like... | null |
2jcwib | why couldn't the eagles have taken bilbo and the dwarves/the fellowship to the lonely mountain/mount doom? | [
{
"answer": "I've been a Tolkien geek for 27 years ... I think I can shed some light on this for you.\n\nGandalf, Saruman, and Radagast are called \"wizards\" but they are actually beings called Maiar. There are tons of them, but Gandalf, Saruman, and Radagast (and two other not mentioned) are part of the Istar... | null |
eotrmu | hot tea tastes wonderful! iced tea is yummy. why does hot tea that's gone cold taste horrific? | [
{
"answer": "Iced Tea tends to have a buttload of sugar in it, more than you would put in hot tea, which offsets the bitterness of hot-tea-gone-cold",
"provenance": null
},
{
"answer": "Because it's not cold it's room temp. Throw in some ice cubes, your favorite sweetener (or not), and some lime/lem... | null |
7kuq1s | Hopi and Aztec religions have a lot in common, minus sacrifices. Were any of the Southwestern nations in contact with Mesoamerica? | [
{
"answer": "In regards to the \"prophesied the arrival of a white man\" statement, perhaps these two previous topics from our [FAQ section on Mesoamerica](_URL_0_) are of interest.\n\n* [Did Moctezuma II really believe Cortes was 'an armor-clad God'?](_URL_2_) by /u/Ucumu and /u/400-Rabbits\n\n* [I've heard th... | null |
56aaf3 | Is there any way for low frequencies of light to constructively interfere to form a higher frequency with minimal energy lost? | [
{
"answer": "You can frequency double light inside a non-linear crystal. If you put this crystal into a cavity - so more or less two mirrors opposite to each other - then you can get conversion efficiencies of up to 90%. This process does not require external energy except for the light you double in frequency... | null |
2wkrqb | Is it bad to take medication you don't really need? | [
{
"answer": "Yes, because you will experience the adverse effects of that medication. Whether or not these adverse effects have any long-term impact on your life is another question and depends on the medication and chance. You may experience no adverse effect, or you may experience a really rare adverse effect... | null |
497y2x | how can we not feel any of our inner organs? or better why do we only feel pain and no other feeling with them? | [
{
"answer": "Because you don't really need to.\n\nActually, you can kinda feel your organs. You can have sensations of pressure or distension in your stomach and bowels. If you take a deep enough breath, you can feel some shifting of your internal organs, or viscera. \n\nBut you're right that, for the most part... | null |
42cw6w | do dogs recognize their own barks? | [
{
"answer": "Well, most of the time people aren't sure of their own voice with a recording... so the same probably applies to dogs.",
"provenance": null
},
{
"answer": "From what ive seen, no.\n\nIn a place I lived one time, I would pass a vet's office on the way to the store. across the field from ... | null |
4ie85v | why do we have the capacity to hate ourselves? | [
{
"answer": "Free thought and free will has many positives and negatives. Increased intelligence means that we also can see the uglier sides of things, and well.... ",
"provenance": null
},
{
"answer": "Humans have evolved as social creatures. In addition to caring about things from our own point of... | null |
33z0ah | how to understand and to visualize the 4th to 10th dimensions | [
{
"answer": "There is no easy way to visualize it but this video does a good job!\n_URL_0_\nEdit:\n\nJust found a way toi visualize the 4\nA point has 0 dimensions.\nA line segment is a 1 dimensional object bounded by 2 0-dimensional points.\nA square is a 2 dimensional object bounded by 4 1 dimensional lines.\... | null |
cw1w6m | what are arrays in programming? | [
{
"answer": "Arrays are like boxes : If you declare an array of integer with 5 in size, you can have have 5 integer in it. If you wish to select the first item, you have to take the 0, then the second is 1, the next is 2 etc... And the last is 4 (because you begin at 0). To put it simple, the last integer of yo... | null |
2uk17q | Why do all objects in space seem to be moving very fast? | [
{
"answer": "Let me flip it around: why does everything on Earth seem to be moving so slow? Massive particles can have any velocity between 0 and 299,792,458 m/s, but on Earth everything seems to be going only a few hundred meters per second or (usually) much less. Well, because atmospheric drag keeps most thin... | null |
27tbd7 | why do humans tend to seek for competition, success and out doing others? | [
{
"answer": "From evolutionary standpoint: To find better mate and reproduce. But the humans are capable of overcoming such base motivations.",
"provenance": null
},
{
"answer": "Natural selection favors such traits.",
"provenance": null
},
{
"answer": null,
"provenance": [
{
... | null |
4b8ygm | Trying to remember the name/location of an ancient battle | [
{
"answer": "You're thinking of the Battle of Ilipa in the Second Punic War, in which Hasdrubal Gisco was the Carthaginian commander, while Scipio Africanus led the Romans. In the leadup to the battle, Scipio would array his heavy Roman troops in the center, with the more lightly armed Iberian allies on the wi... | null |
71cyfg | What do we know about Native American cuisine? | [
{
"answer": "I have answered a number of questions on Native American, specifically Mesoamerican, cuisine that you may find informative. Please feel free to ask any follow-up questions.\n\n_URL_1_\n\n_URL_4_\n\n_URL_5_\n\n_URL_6_\n\n_URL_3_\n\n_URL_2_\n\n_URL_0_",
"provenance": null
},
{
"answer": "... | null |
2ypdd0 | Prior to the Emancipation Proclamation, when property in Confederate territory was confiscated by the Union what became of slaves which were legally part of confiscated estates? | [
{
"answer": "Good question. Lincoln was very keen to dampen, not fan, the flames of war during the early years of the Civil War for a couple of reasons. First, border states like Kentucky were still on the fence about whether or not they were going to secede. Lincoln didn't want to give them a push one way or a... | null |
y3cta | how the us supreme court decided the 2000 presidential election, and how is the decision viewed today? | [
{
"answer": "With all states except Florida counted, neither candidate had the majority of 270 electoral votes they needed to win. The 25 electoral votes from Florida would give either candidate the Presidency.\n\nThe Florida vote was extremely close. There was a long process of a hand count which ended with ... | null |
22mbz4 | Found brittle WW2 newspapers, Need suggestions re: preservation | [
{
"answer": "So first off you actually want to maintain a dry environment (35%) humidity or less for the paper. Paper in a Humid environment may actually disintegrate faster. \n\nIt's important that you try not to touch the paper with your bare hands the oil on your fingers can actually cause further break down... | null |
1vgn7b | What capital cities have never been sacked or conquered? | [
{
"answer": "Sorry, this question has been removed for being a [throughout your era question, which the rules don't allow](_URL_0_).",
"provenance": null
},
{
"answer": null,
"provenance": [
{
"wikipedia_id": "3111390",
"title": "Ariccia",
"section": "Section::::His... | null |
a7vjq5 | what even is a permanent record? | [
{
"answer": "Student records commonly include details such as class grades, important test scores, attendance records, health and immunization information, discipline records, special awards conferred, previous schools attended, and so on. In other words, these 'permanent records' are typically just a log of va... | null |
5mufw4 | What properties of beet juice make it a useful additive for combating snowy/icey roads? | [
{
"answer": "I don't have an answer for you but here's a [link to a relevant article.](_URL_0_)",
"provenance": null
},
{
"answer": "I'm not 100% sure but: \nTrimethylglycine found in the byproduct produced in the processing of sugar beets. Trimethylglycine is a freezing point depressant, similar t... | null |
267baq | in ocean searches for lost ships / planes, who pays the private companies for their time and resources? | [
{
"answer": "[This](_URL_0_) may help you understand what happens.\n\n\"Salvage law has as a basis that a salvor should be rewarded for risking his life and property to rescue the property of another from peril. Salvage law is in some ways similar to the wartime law of prize, the capture, condemnation and sale ... | null |
8l0uab | Is it possible to be immune to certain drugs? | [
{
"answer": "In addition to what the other poster wrote, there are cases where a person is a hypermetaboliser of certain drugs, to the point that normal dosage may be ineffective. Sometimes a larger dose can be given to overcome the problem but it may still be short acting and largely ineffective, and if the me... | null |
52qf1v | How were deserters from the U.S. army punished during/shortly after the revolution? | [
{
"answer": "Deserters from the Virginia militias faced the \"general discretion of the court martial\" for the first two years of the Revolution and then a fine not more than two month's pays or imprisonment of not more than one month. In the fall of 1777, additional months of service was the most common form... | null |
sio5w | Science: How close are we to curing HIV/AIDS? | [
{
"answer": "A bone-marrow transplant from someone immune to AIDs can cure you. It's horrible painful and a tad expensive, and requires you finding someone immune, but it's possible.",
"provenance": null
},
{
"answer": "We're not close to curing it yet. Look up a paper by Pat Schlievert and Ashley H... | null |
2zc07r | how the double-heading (double engine/locomotives) railways work efficiently ? | [
{
"answer": "Multiple-unit train control - basically single control for all the engines running one train have been around in different forms from 1920's",
"provenance": null
},
{
"answer": null,
"provenance": [
{
"wikipedia_id": "1057230",
"title": "Railway roundhouse",
... | null |
1ihdav | What are some examples of beneficial microorganisms? | [
{
"answer": "Microbiologist here. Microorganisms are unbelievably important for human and environmental health, and without them, life as we know it wouldn't exist. Some examples to answer your question:\n\n*E. coli* is used to produce synthetic insulin (_URL_2_)\n\n*S. cerevisiae* is the yeast (a type of fungu... | null |
5vb49k | What is the correct way for loading a Napoleonic muzzle-loading flintlock musket or rifle? | [
{
"answer": "First of all, I'd like to state that while I Have read many of Cornwell's Sharpe books, I do not have any copies at hand, so I can't directly reference the details of loading, per Cornwell's descriptions and how accurate they are, so I'll speak generally to the process, and the possible source of t... | null |
726mqy | How come there are no famous or well-known Civil War songs from the North? | [
{
"answer": "So... this is one of those questions where I'm hard pressed to answer exactly as asked, as the premise is somewhat leading. When a question is \"Why don't I know about [X]?\", \"Why wasn't I taught about [Y]?\", and so on, the answer is often less about an overarching narrative than it is about you... | null |
2evki3 | Can someone explain DNA sequences? | [
{
"answer": "Each side connects to a different carbon on the backbone, either 5' or 3'. Generally the convention is to express sequences from 5' to 3', so it'd be like 5' ATCGATCGATTACA 3'. The opposite strand would go 3' to 5'.",
"provenance": null
},
{
"answer": null,
"provenance": [
{
... | null |
1jfvnp | why is a nation citizen id card in the us a bad idea? | [
{
"answer": "there are millions of legal residents here that aren't citizens. they all can get a state ID or a driver license. \n\n",
"provenance": null
},
{
"answer": "It's not. The problem is paranoid types would begin talking about privacy and creeping fascism and crazy religious nuts would cal... | null |
f8alsy | Why did Carthage rely on mercenaries so heavily, while other Mediterranean powers of the same time seemed to be drawing more from their citizenry? | [
{
"answer": "More input is always welcome; for the meantime, this answer by u/Jollydevil6 [on the Carthaginian army](_URL_0_) may be of interest to you.",
"provenance": null
},
{
"answer": null,
"provenance": [
{
"wikipedia_id": "20663625",
"title": "Ancient Carthage",
... | null |
7wdnxs | Is USB charging more battery friendly than charging with AC charger? | [
{
"answer": "There is a lot of different things going on. Devices which charge from USB get up to 500mA as a basic source. The device can negotiate for more current by asking for it. From an electronic design standpoint, it is more effort to put that into a design that normally doesn't communicate with a comput... | null |
q0977 | why would seeing yourself when time traveling mess up everything? | [
{
"answer": "If you saw yourself then that may alter the \"timeline\" that you've been on. Remember in the film Jurassic Park where the \"butterfly effect\" is explained? The idea is that a small alteration in the past (like seeing yourself) may have dire consequences on the future. \nIf you change this timeli... | null |
5jqc4h | if the moon's near side is locked onto always facing the earth, how does it rotate every month without us seeing the far side? | [
{
"answer": "Because its rotation is sync'd up with its revolution around the Earth as you can see [here](_URL_0_). While the moon spins, it is also revolving around the Earth so that the same side is always facing us.",
"provenance": null
},
{
"answer": "The moon does not seem to be spinning but ap... | null |
30s067 | why, when using the same tv and console, do i need the volume on, say 20 to watch netflix comfortably, but then on 40 or 50 to hear hbo go the same way? | [
{
"answer": "I don't know, but I'm curious to read responses. \nI'm assuming you mean from the same input source and not swapping like a digital box to a computer I put\n\nBut my HBO GO is much louder than my Netflix and I have to turn down to watch it. I use Apple TV",
"provenance": null
},
{
"answ... | null |
omn9o | So i tried applying super glue with a Qtip, moments later got a cloud of awful smelling smoke and the glue was almost instantly dried. Wtf? | [
{
"answer": "What were you applying the glue to?",
"provenance": null
},
{
"answer": "Cyanoacrylate (crazy glue) [reacts](_URL_0_) strongly with cotton.",
"provenance": null
},
{
"answer": null,
"provenance": [
{
"wikipedia_id": "19360092",
"title": "Jenkem",
... | null |
5gxedo | Why has Texas become so much more prosperous than its Great Plains counterparts? | [
{
"answer": "Central Texas is largely covered with cedar trees and oak groves (in the Hill Country), with large Cypress along the rivers. It can look Savannah-like when landowners clear all of the cedar in these places. Central Texas contains an abundant number pecan trees and other hardwoods, with large bald c... | null |
17om6e | Can Animals Identify Their Younger Selves? | [
{
"answer": "Most animals can't even identify themselves in front of a mirror. This includes dogs\\cats\\horses etc. \n\n_URL_0_\n\nFrom the wiki:\n\n > Animals that have been observed to pass the mirror test include:\n\n > \n\n All great apes:\n Humans – Humans tend to fail the mirror test until they... | null |
rvx4k | What are some examples of 1920's swing-dancing clothing? | [
{
"answer": "Skirts, trousers, shirts...what exactly are you looking for, here? [this](_URL_0_)?",
"provenance": null
},
{
"answer": null,
"provenance": [
{
"wikipedia_id": "162255",
"title": "Swing (dance)",
"section": "",
"start_paragraph_id": 1,
"... | null |
281xed | Do other animals get stretch marks? if not, why? | [
{
"answer": "Yes. Rolls Royce only use bull hides in the leather on their cars because female cows can get stretch marks more easily, just like human women. To my understanding, stretch marks are scars from skin being stretched until it breaks. You can get them from gaining weight quickly and this happens more ... | null |
3aj2bh | What are the most interesting human artifacts with uses that are unknown or disputed? | [
{
"answer": "Stone Henge. Scientists have used computer models to see what the sky looked like when stone henge was built. The stars were in different positions thousands of years ago so scientist have to rethink what it was pointing to and what made those stellar objects so important.",
"provenance": nul... | null |
h2b6c | Expansion of space ≈ contraction of Planck length? | [
{
"answer": "Well the short answer is no. The Planck length is just a length you get by combining three of the constants of our universe, G, h and c (gravitational constant, Planck's constant (quantum of action), and the speed of light). We could rearrange them a bit and come up with a mass of a few micrograms,... | null |
1442nx | why is it that when an object falls from orbit, it goes faster than terminal velocity? | [
{
"answer": "Do you mean faster than TV at that particular point or faster than TV would be nearer the ground? TV will vary depending on how high you are as the atmosphere is thinner as you go up and so TV will be higher.\n\nAn object entering the atmosphere going really fast might be going too quickly for the ... | null |
7cqzxv | Can someone explain the galaxy rotation graph? | [
{
"answer": " > v = sqrt(GM)/sqrt(r)\n\nThis would be the correct orbital equation if all the galaxy's mass were concentrated in a point at the center. Now, there is a black hole at the center, but [its mass](_URL_0_) is no more than a few millionths of the of the [total mass of the galaxy](_URL_1_): most of ... | null |
d4pvxm | why are there different levels of spf in products? why is the highest not always the best? | [
{
"answer": "Higher SPF sunscreens will prevent tanning, and a lot of people want to tan a little when they are out in the sun. Maximum SPF value is good for young kids, people with sensitive skin, people with a predisposition to skin cancer, and people working for long periods in the sun. For people who just w... | null |
1o0bf7 | Via a similar process to electrolysis, could we extract a viable amount of oxygen out of CO2? | [
{
"answer": "No matter how you try to do this, there's a problem: what you're talking about is the reverse of the combustion that formed the CO2 in the first place. That burning gave off a significant amount of energy, so that's what would have to be put back in to run things in reverse. You'd go back to oxygen... | null |
769tom | during traffic stop how police communicate with drivers who don't speak english? | [
{
"answer": "Police departments actively hire officers who speak the languages common in the area, and offer a salary bump to ones who learn them. One of them would be called in as a translator if necessary.\n\nAnd even the officers who don't understand the language will have a cheat sheet and quickly learn th... | null |
ak84cs | how did humans train horses to willingly charge into danger or death? | [
{
"answer": "Horses, like all animals, don't have a concept of their mortality.\n\nThey have instincts which tell them to avoid trouble that helps keep them alive.\n\nHowever once you get a horse used to the sounds of warfare, they'll charge right in to wherever you point them.\n\nHorses that were too scared si... | null |
abj2mm | Considering the enormous number of memories we retain into old age, what was all of that brain matter being used for before these memories were stored? | [
{
"answer": "Memory is a huge and complex topic which is not well understood. There are different kinds of memory, but you seem to be asking about [long-term explicit memory](_URL_2_).\n\nSpeaking mostly from the realm of artificial neural networks, which are only loosely modeled on brain physiology, I think t... | null |
bs7xy1 | Nazi literature, poetry, films or other artistic works? | [
{
"answer": "Though it doesn’t get into what ultimately became of Nazi books, films, and artwork after the war, you should definitely take a look at u/commiespaceinvader’s in-depth response to [Were there any truly talented Nazi artists, musicians, or writers who would be renowned if not for their political vie... | null |
q8szb | What are the other names for "The Great War"? | [
{
"answer": "from Wikipedia: The Second Fatherland War was the term given by contemporary Russians to both the Eastern Front of World War I and the Eastern Front of World War II. Both terms attempted to link the current war with the French invasion of Russia in 1812, which had been termed the \"Fatherland War\"... | null |
nnnmt | how to progressively learn math. | [
{
"answer": "Go to any university website and then look up the books from the lowest mathematics course, which is probably \"introduction to trigonometry\", to whatever is offered in the Ph.D courses. When learning from these books, do the exact opposite of what you would do in university. Study them to learn a... | null |
3llsjb | why is there an apparent war between pc gamers and developers? | [
{
"answer": "Developers just want money but don't give a shit about the gamers. They are like *\"We have your 60€, not our problem if the servers are down every 10 minutes.\"*",
"provenance": null
},
{
"answer": "Piracy and the dominance of tablet/browser mini-games is why developers are money-grubb... | null |
6jsloh | What is the highest frequency of light that the human eye can detect/process? What is the lowest? | [
{
"answer": "We can only see visible light, roughly 390 to 700nm in wavelength. 3x10^8 / 390x10^-9 gives the highest frequency. 3x10^8 / 700*10^-9 will give the lowest frequency. This [wikipedia picture](_URL_1_) does a good job showing the three cone cells and their contribution to our perception of [visible l... | null |
1k5hao | elliptical curve cryptography - how does it work? | [
{
"answer": "OK, first off it's \"elliptic curve\", not \"elliptical curve\". An elliptic curve is the collection of points (x, y) in the plane that satisfy\n y^2 = x^3 + ax + b\ntogether with a special point (∞, ∞). Different choices of a and b give different curves. I'll talk about the elliptic curve ve... | null |
1d7kdr | How/Why can matter go from a solid state to a gaseous state? Completely skipping over liquid, and vice versa...? | [
{
"answer": "Molecules will occupy a state of aggregation to minimise their free energy. For particular conditions of T and P, this is a trade off of energy and entropy. For some molecules, the additional reduction in entropy by going directly to a solid is more than offset by the reduction in enthalpy so th... | null |
1rx58w | why does yahoo answers rate higher than reddit? | [
{
"answer": "probably because yahoo is huge and has more users in comparison to reddit and therefore is considered the more relevant search result",
"provenance": null
},
{
"answer": "You know, this raises some more questions for me. I tried looking up the listings of the most visited sites or most ... | null |
20aj1e | In movies, there's frequently a standoff with two people pointing a gun at each other. Is human reaction time quick enough for the second person to get their shot off before dying if the first fires and hits them in the head? | [
{
"answer": "Really depends on the guns and distance involved.\n\nFrom one source, we see bullet speeds ranging from ~180 m/s (.38 special) to ~1200 m/s (.22 swift) (Petzal, 1992).\n\nEckner, Kutcher, and Richardson (2010) found that people respond to visual stimuli at ~270ms, but earlier studies found reaction... | null |
1kj056 | Did the ancient Romans probe far beyond the borders of their empire? | [
{
"answer": "Yes, the Romans were quite nosy. I've made a couple of comments on this subject ([1](_URL_0_), [2](_URL_1_)). To reiterate myself (sorry for this comment being a bit of a mishmash):\n\nThe Romans actually invaded Arabia during Augustus' reign, under a commander named Gallus, and even besieged the... | null |
wm788 | what exactly is a continent? just a part of the earth that rises above water? how was the first continent made? | [
{
"answer": "I cant answer the question about the formation of modern Earth or Pangaea, but I can say that the word continent is poorly defined.\n\nHere is a [video] (_URL_0_) talking about it. \n",
"provenance": null
},
{
"answer": "Pangaea was far from the first super-continent. There were many be... | null |
1odb6e | why does de-fragmenting a solid-state drive reduce it's lifetime? | [
{
"answer": "Life span of a solid state drive is determined by how many times each unit of storage can be read and written to.\n\n\n\nAll de-fragmentation takes parts of files that that have been stored all over and re-arranges them so they are all together.\n\n\n\n\n\nThis requires a lot of reading and writing... | null |
5fmrqd | What did the Romans think of Stonehenge? | [
{
"answer": "[A similar question was asked a couple of years ago.](_URL_0_) I second u/QVCatullus in that I don't believe there are any Ancient Roman mentions that we know of currently. Not saying that there aren't any, but we presently don't know what they thought of it.",
"provenance": null
},
{
"... | null |
5o1bp6 | Are there any statements or interviews by the pilot/plane crew who dropped the atomic bombs on Hiroshima and Nagasaki | [
{
"answer": "Brigadier-General Paul Tibbets, the pilot of the *Enola Gay*, gave interviews to the *Columbus Dispatch* and some of them are quoted in [his obituary](_URL_1_).\n\nHere's [another interview](_URL_0_) from a documentary he did.",
"provenance": null
},
{
"answer": "There have been many, m... | null |
5dx4bq | Why did Pangea break apart and the continents move away in such a manner as if they were "floating", without regard for what lies underneath the ocean? | [
{
"answer": "Alright, strap in, we have a lot of ground to cover before we can answer your question fully. First, there are two broad kinds of crust, continental and oceanic, which differ in their composition, densities, and other physical properties. [Continental crust](_URL_4_), which forms the bulk of areas ... | null |
tawjk | Is it possible to be allergic to electricity? | [
{
"answer": "It is not possible to be allergic to electricity as electric currents do not interact chemically or physically in a way that would provoke an allergic response. You might provoke some sort of response with a high current through an electrical burn or overstimulation of neural pathways but this woul... | null |
49zxbp | why are there time zones within the continental us with a one hour spacing? | [
{
"answer": "The choice is really a bit arbitrary--but the fewer time zones, the simpler everything is to manage. There are a few places with 30-minute or even 15-minute offsets, but on the whole one-hour time zones have become the global norm. It strikes a good balance between convenience of administration and... | null |
1j04oy | How were monarchies first established after the fall of the Roman Empire? | [
{
"answer": "The early feudal-type system ('feudalism' as an all-encompassing description of medieval society is a disputed subject these days) that the later monarchies rose out of largely came out of the late Roman Empire's villa system (which involved a landowner and hired 'peasants' working said land). In a... | null |
2g28q4 | how can the us have so much foreign debt yet still be the most economically powerful nation in the world? given the current trajectory, how much longer will this last? | [
{
"answer": "The US actually has a lower debt than Germany, Canada, Egypt, Spain, France, The UK, Singapore, Greece, Japan, and a host of other countries. When we look at public debt we do not compare total debt between countries, we compare debt to GDP (Gross Domestic Product). In that metric the US is actuall... | null |
7ntxqy | what causes rhotacism? (the inability to pronounce the letter “r”) | [
{
"answer": "It is dependent on how you hear sounds and the way you were raised. If your family mostly uses trilled R’s then you would have a slightly higher chance of developing it. This is abundant in Asian countries.\n\nA better explanation would be from this video:\n\n_URL_0_",
"provenance": null
},
... | null |
1uhbvs | the difference between 3/4 and 6/8 timing in music. | [
{
"answer": "The count on 3/4 is three beats, while 6/8 is two triplets. It's a subtle difference, but enough to change how the music flows.\n\n3/4 - one TWO three, one TWO three, etc\n\n6/8 - tri-pl-et, tri-pl-et, etc. as a one TWO, one TWO count.",
"provenance": null
},
{
"answer": "What TimeTrav... | null |
a0fg91 | How important was the Eichmann Trial in public awareness of the Holocaust? | [
{
"answer": "I know this is over a week old, but I didn't want to leave this question unanswered. \n\nFrom the end of the war until the Eichmann trial, the world obviously knew of the Holocaust and the general horrors that had occurred. Perhaps they knew someone that had been a victim of the Holocaust and so th... | null |
2ajko0 | the primary purpose of the supercomputer sequoia is nuclear weapons simulation. what does it mean? | [
{
"answer": "They're simulating weapons to make sure they work so they don't have to physically test them. Those simulations are hard to do, and not always accurate if you don't have enough computing power. Nuclear physics is really complicated.",
"provenance": null
},
{
"answer": null,
"prove... | null |
2v30h1 | what part of a jet engine actually generates the thrust? | [
{
"answer": "The gas being forced out of the back creates the thrust. In the combustion chamber the fuel turns into a large amount of very hot gas, which can only go out the back due to the air being pushed in.\n\nAfterburner is where they spray fuel into the exhaust, where it combusts again, turning the liquid... | null |
3aoewi | Was there any damage to the Vatican City during WWII? | [
{
"answer": "The Vatican was hit by bombs twice during the war, once in November of 1943 and again in March of 1944. The second bombing was done by an Italian plane, it killed one person and damaged the Pontifical Urban University and the Palace of the Holy Office with small bombs. \n\nThe 1943 bombing damage... | null |
7hqbgv | Does a USB-C - USB-C charger extension cord slow down the charge? | [
{
"answer": "First off, the battery charger is actually built into the phone. The wall wart is a constant voltage power supply. Some USB-C power supplies have the ability to output one of 2 or 3 different voltages, but they are voltage regulated. \n\n All charging cables have resistance. Resistance causes volta... | null |
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