title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
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[
"AskScience AMA Series: We're Hayden Reeve, Steve Widergren, and Robert Pratt from Pacific Northwest National Laboratory, and we study the power grid. We recently found using a transactive energy system could save U.S. consumers over $50 billion annually on their electrical bills. Ask us anything!"
] | [
false
] | Hello Reddit, Hayden Reeve, Steve Widergren, and Robert Pratt here. Our team of energy experts study the U.S. power grid, looking at ways to modernize it and make it more stable and reliable. We're not fans of brownouts. Recently, we conducted the largest simulation of its kind to determine how a transactive energy app... | [
"Saving $50 billion is awesome.",
"Now, what would it cost to GET there?"
] | [
"I have 2 questions.",
"What incentives do power grid operators and suppliers have to reduce their annual revenue by participating?",
"What daily participation is expected by consumers? You mention in the abstract the fatigue from voluntary curtailment in CA."
] | [
"How do we prevent what you're proposing from resulting in 50B more profit for someone? It seems that historically when methods to track consumers are implemented they result in providers more effectively reducing their provided goods and services to the absolute lowest level while maintaining the prices the marke... |
[
"I am no astrophysicist. The consensus is that the moon was formed when the proto-Earth was struck by a body the size of Mars. The ejecta and (mostly) the Mars-sized body became the moon. Why should it have a remotely stable orbit?"
] | [
false
] | I understand why the Earth still has a stable orbit (it and the impactor were moving near the same speed and were in the same orbit), but why should the mass left over from the collision have enough kinetic energy remain in orbit and not fall back? I'm picturing the collision as something of a bounce, as inaccurate as... | [
"Many. Simulations have been done to Christmas and back. What ends up happening is that the ejecta has a centre of mass that's on the expected elliptical trajectory, but it also has angular momentum about that centre of mass. As a result, as the ejecta congeals its orbit becomes more circular."
] | [
"It is believed the earth and this hypothetic planet (Theia to some) shared an orbit, with Theia occupying the stable Lagrangian points 60",
" ahead (L4) or behind (L5) of the earth.",
"However, these points are only stable if Theia's mass is low relative to earth's. As it accumulated more matter, the orbit be... | [
"No no. Escape velocity is the velocity required for a mass to rise against gravity ",
" Mass moving at escape velocity or greater will not have an elliptical orbit at all. It'll move in a hyperbolic trajectory."
] |
[
"\"Scientists suggest spacetime has no time dimension\" - I read through this article and still don't get it. Can someone explain this to me?"
] | [
false
] | null | [
"sensationalism mostly. Look, we physicists hate to keep all our hopes in one basket. So a few of us go out and think up new answers to problems that haven't yet arisen. They aren't necessarily \"science.\" Just interesting ideas that may someday be justified by data. We aren't suppressing non-mainstream thought or... | [
"Well, I can't access the paper (from behind my university paywall, which is ",
" unusual), and it's not on the arXiv, so I can't really comment on it. In fact, the fact that I can't find a single paper (including this one) by ",
" of these three authors suggests they're not exactly the world's best-established... | [
"Okay, the article makes a lot of sense now. Thanks for putting this into perspective."
] |
[
"Why can't I apply Kirchhoff's second rule when analyzing LR circuits?"
] | [
false
] | I am in the process of watching Professor Walter Lewin's MIT lectures on Electricity and Magnetism. In , during the first fifteen minutes, Prof. Lewin criticized many textbook authors for misapplying Kirchhoff's rule when analyzing LR circuits, and clarified that Faraday's Law should be used instead. My study partner i... | [
"Kirchhoff's rule somewhat requires us to invent additional notions that aren't necessarily intuitive to the elements in the circuit. Namely the voltage rise/drop across an inductor. Surely we can define one, as it can absorb or donate energy to the electrons moving through the inductor, but it's a bit more like fo... | [
"This is correct. Kirchoff's Rule as it is used in an electrical engineering class is not the original rule at all but just a similarly worded hack. The fact that we can deal with non-conservative fields within the traditional framework that requires conservative fields (i.e. requires the fact that every point ha... | [
"Kirchhoff's rule somewhat requires us to invent additional notions that aren't necessarily intuitive to the elements in the circuit. Namely the voltage rise/drop across an inductor. Namely the voltage rise/drop across an inductor. Surely we can define one, as it can absorb or donate energy to the electrons moving ... |
[
"How complex is the chemistry within a single bacteria?"
] | [
false
] | null | [
"The chemistry of any living organism is wildly, nearly incomprehensible complex. The individual reactions are all fine, to anyone who's had some basic organic chemistry and/or biochemistry. But the intricate networks of them, the timing and placement, the ways by which all these reactions are accomplished in netwo... | [
"The individual reactions are all fine, to anyone who's had some basic organic chemistry and/or biochemistry.",
"Once they've been worked out maybe, but I still think it takes researchers of considerable genius to work out the details in the first place. I mean, the chemistry of one of the most fundamental cellul... | [
"For a lot of metabolic pathways, the chemistry is amazingly similar to what you have going on in your cells....so very complex. What bacteria have that is different is mostly concerned with how the 'nucleus' is set up...since they don't have a membrane-bound nucleus and how they communicate with other cells and t... |
[
"Why can't we create a perfectly straight beam of light with optics? What makes lasers so special?"
] | [
false
] | Just looking at the inside of camera lenses, it seems we know optics well enough to control light with a pretty high degree of precision. So, why is it that I've never seen light focused into a perfectly straight beam via glass lenses or mirrors before, and instead lasers beams have to be generated through special las... | [
"I think it's a shame that you are not getting a good answer here to such a technologically important question, especially since there is a clear and straightforward answer. I've dealt quite a bit with the characteristics of lasers and other beams, so I'll give it a shot.",
"Laser light is quite special compared ... | [
"An excellent xkcd article on etendue, if you haven’t seen it: ",
"https://what-if.xkcd.com/145/"
] | [
"Non-laser light can be kept in a straight beam about as well as a laser can, but all light will spread out over distance, even lasers.",
"Think about a sunbeam. Rays from the sun are basically parallel since the sun is so far away, so on cloudy days when most sunlight is blocked and little bits get through you c... |
[
"Is there any evidence to support exercise helping to cure an existing minor bacterial or viral infection?"
] | [
false
] | null | [
"The immune system is depressed during exercise, since the body needs resources to deal with other things (namely, the metabolic and physical stress of exercise). Light to moderate exercise, which raises your cardiac output with minimal stress, can help circulate immune cells to the infected regions, but the effect... | [
"I'm on mobile, so I can't link the PDF directly, but here's the abstract on the web and you can get the PDF of the full study from there. ",
"http://eric.ed.gov/?id=ED470693"
] | [
"I'm on mobile, so I can't link the PDF directly, but here's the abstract on the web and you can get the PDF of the full study from there. ",
"http://eric.ed.gov/?id=ED470693"
] |
[
"Do insects feel pain?"
] | [
false
] | null | [
"Comment from previous thread:",
"http://www.reddit.com/r/askscience/comments/qsemo/do_insects_feel_pain/c402zyp",
"\"5-year psychology/neuroscience student here:\nThis is a difficult question. The reason? How can you ask a bug how it feels? Pain research to my understanding is always walking to fine line betwe... | [
"I understood the answer would be something like this. I just wanted the details, so thankyou. I realize now that my wording was way too general."
] | [
"Yes! Pretty much anything with a brain can feel pain. "
] |
[
"Is it possible to achieve real time communications between the Earth and Mars?"
] | [
false
] | If not, what is the minimum time that would take to transmit a single bit of information between the planets? | [
"No. The distance between the two planets makes it prohibitive to achieve real-time communications due to the finite speed of the signal (which is actually the speed of light). This may vary between 4 minutes when the planets are at closest approach to about 20 minutes when they are farthest from each other.",
"A... | [
"Yes, the Sun is a black body, so it will absorb all radio signals. There's a communications blackout during conjunctions (i.e. when the Sun and Mars are on the same side of the sky as seen from Earth, which means the planets are at opposite sides)."
] | [
"It's exactly the same. Earth is behind the Sun from Mars' POV when Mars is behind the Sun from Earth's POV.",
"(Pedantic detail, what we call transit is different, this would mean Earth getting in the middle so that Mars sees it as a black dot covering the Sun. In this case no blackout would occur as we're on th... |
[
"Does a cold ever evolve while you have it, becoming a new cold that keeps you sick longer?"
] | [
false
] | I swear I've had 3 colds in a row, but that got me wondering, what if it was just the same cold evolving? | [
"Yes, some viral diseases do evolve inside of you. RNA viruses mutate especially fast, and many forms of cold are caused by RNA viruses such as the ",
"rhinovirus",
".",
"However, human immune systems also \"evolve\" rapidly in response to infection through a process known as ",
"somatic hypermutation",
... | [
"Get a room, you two"
] | [
"Get a room, you two"
] |
[
"If Newton's Law of Gravitation is only meant for point masses, how come we use it to calculate force of gravity on a massive body like Earth?"
] | [
false
] | null | [
"For extended bodies, the force law holds for each infinitesimal piece, and so the total force is the sum (i.e., integral) of each of these infinitesimal forces.",
"For a spherically symmetric object ",
" (this means the object is a sphere and its mass density depends only on the distance from the center), it t... | [
"In other words, spherically symmetric objects act as if they were point masses, but only on their exterior.",
"Furthermore, if you are on the interior of an spherically symmetric object, the gravity of the mass at radiai greater your own cancels out and you will only feel the gravity of the subsphere at your rad... | [
"No. The mass density of Earth is not uniform. The gravitational field actually increases for a bit as ",
" decreases, then it starts to decrease to 0. ",
"This graphic",
" shows the gravitational acceleration as a function of depth. The curve labeled \"constant density\" is the acceleration if Earth were a u... |
[
"Why do domestic mammals (dogs, cats, cows, horses) have tails?"
] | [
false
] | [deleted] | [
"Most mammals have tails, though some have lost it through evolution when it no longer fills any meaningful function. In these cases, they still have at least some functionality. Cats use their tails for balance and communicating, dogs also use their tails to communicate and cows and horses swat flies and other irr... | [
"horses swat flies and other irritating insects with their tails.",
"They will also intentionally swat you in the face while you're picking their hooves. "
] | [
"Haha, I can believe that. The stories I hear from friends and family about horses make them out to be some real clever pricks sometimes. Part of why I've opted to stay away from them for most of the time."
] |
[
"How have coyotes managed to thrive alongside humans while wolves have been driven to near extinction?"
] | [
false
] | null | [
"It seems that coyotes have been able to thrive alongside humans ",
" the wolves have been driven out. ",
"Prior to around 1700 the range of the coyote was limited to the S.W. US and the plains. When humans began to eliminate the wolves, bears and cougars, the coyotes were able to move into territories where... | [
"But why haven't they been hunted out in a similar fashion?"
] | [
"Wolves were hunted into extirpation because humans viewed them as a threat (some still do). They are seen as cunning, vicious, predatory and they are seen as at best competing with humans.",
"\nI just as an exercise quickly googled the phrase \"why kill wolves\" and the first result lists 6 reasons to kill wolve... |
[
"Give the potential use of graphene as a supercapitor, are rail guns more plausible in real world applications?"
] | [
false
] | [deleted] | [
"One problem with rail guns with electrolytic capacitors was the large currents (and therefore magnetic fields) within the capacitor itself caused forces which damaged the capacitor during firing.",
"This would suggest the electrolytic capacitor is power-density limited. It seems unlikely that graphene supercap... | [
"I have a friend that works on the navy rail gun projects. They are not having issues with the power, they know how to get the insane currents they need in the Mega amp range. The big issues are lifetime of the rails and multiple shot capability. Primarily material science issues."
] | [
"Graphene will not help most of the challenges with rail guns, although it might be used as an improvement upon existing designs, most of what Graphene offers they have already passed as a technological barrier. There are other issues right now; still rail guns are not too far off, a fully functioning, repeat fire... |
[
"Vision correction?"
] | [
false
] | Are there any scientifically backed methods of vision correction other than laser surgery or eyeglasses/contacts? If not, are there things that have been indicated as culprits of poor vision (such as staring at a monitor for extended periods)? | [
"Long sightedness and short sightedness are symptoms caused by the cornea hardening and no longer being able to adjust to the right shape so that the image focused onto your retina is sharp",
"The cornea never bends!",
"When light enters your eye, it refracts at the cornea, aqueous humor, lens, and vitreous hum... | [
"Near/far sightedness in most people is caused by the eye just being the wrong shape",
"Just to add that (I believe) that such 'wrong' shapes can in turn be caused behaviour. Particularly by lots of time spent focusing at things close up (excessive straining being a cue that the eyes natural refractive power is i... | [
"Upboat to because I don't mind the word 'alas'.",
"It's though that behavior has some effect on acuity, but the extent is unclear and thought to be minimal (second hand info from an ophthalmology researcher). However, my vision has improved by half a diopter since I started grad school, so go figure!",
"My gue... |
[
"What am I missing on Newton's third law?"
] | [
false
] | [deleted] | [
"You couldn't calculate the mass of the earth in this scenario unless you could (very accurately and precisely) measure the Earth's acceleration away from you, which is effectively negligible.",
"Also you are convoluting a couple different things here - a 200lb person jumping isn't the same as a 200lb weight drop... | [
"Force is mass x acceleration, isn't it? Well the earth doesn't accelerate toward me when I jump, does it? ",
"The forces affecting you and the Earth are indeed equal. Also, the force affecting you equals your mass * your acceleration, while the force affecting the Earth equals Earth's mass * Earth's acceleration... | [
"After reading most your posts I think this is the key thing you are missing - ",
". ",
"Imagine yourself sitting in a chair. You feel the force of gravity pulling you down. Because of it, you exert a force on the chair (equal to our weight). Now if that were it, you would break the chair and continue to fall, ... |
[
"Can scientists observe chemical reactions at the molecular level?"
] | [
false
] | I'm just having a thought while studying some chemical mechanisms. Is there a way to see proton/atom transfers between molecules Or are mechanisms purely theoretical? | [
"You don't even need xrays to see chemical reactions. Zewail's Nobel Prize was for watching chemical rxns with visible light lasers."
] | [
"You don't even need xrays to see chemical reactions. Zewail's Nobel Prize was for watching chemical rxns with visible light lasers."
] | [
"1999 Nobel Prize in femtochemistry:",
"http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1999/press.html",
"http://en.wikipedia.org/wiki/Femtochemistry",
"Femotchemistry essentially allows us to understand reaction mechanism by probing reactions on the femtosecond timescale. This provides direct evi... |
[
"What are some of the negative effects of a diet heavy in soy products/soy protein?"
] | [
false
] | I came across a outlining several serious, negative effects of consuming soy products and soy protein. I'd previously heard about the study that linked soy consumption to decreased fertility in men but the other effects (decreased ability to lose weight, decreased ability to absorb protein, mineral deficiencies, higher... | [
"I'm going to take a wider view of this question. ilovelegos413 brought up a good point with the estrogen mimic issue. ",
"I have a question for you though, why consume a diet heavy in soy-protein in the first place? There are many cheaper, less processed protein sources that have a lesser chance of affecting ... | [
"Thanks. The 'Health Risks' section of the wiki page was indeed helpful."
] | [
"Thanks for the reply. I posted this because I was curious more than anything. I don't have a soy protein heavy diet but I had never heard of some of the effects described in the blog post. I was (lazily) trying to find out if the post was a mostly sensationalist junk or if it was actually grounded in facts. It app... |
[
"Around 9% of Coronavirus tests came positive on July 9th. Is it reasonable to assume that much more than ~1% of the US general population have had the virus?"
] | [
false
] | And oft-cited figure in the media these days is that around 1% of the general population in the U.S.A. have or have had the virus. But the percentage of tests that come out positive is much greater than 1%. So what gives? | [
"There was a study done in New York around 3,000 participants that were composed of people who entered markets in stores. I think this was like a few months ago. They did a blood sample of all these people and determined that between 9 and 15% had antibodies. And because they also tested the rural areas outlini... | [
"Current estimates put the overall percentage of Americans that have been exposed at around 6-7% from the CDC. ",
"The problem is that we really aren't testing people unless they're showing symptoms, or are on someone's contact trace. Hell, I have someone in my house showing symptoms and currently awaiting test... | [
"At the time of that study the antibody tests had a very high false positive rate. Not sure if they have developed better tests since."
] |
[
"Why does being wet sometimes decrease friction, like when slipping on a wet floor, but at other times increase it, like when trying to remove a damp wetsuit?"
] | [
true
] | [deleted] | [
"The decrease of friction is due to simple lubrication. The water between two surfaces can flow (shear) with less viscous resistance than the friction would be of the two dry surfaces sliding against eachother.",
"The cases where water seems to increase friction is actually the water increasing ",
", a force pu... | [
"Ah, that has everything to do with the thickness of the water layer, the shape of the interface between the solids, and how much water is around. The thicker it is, the stronger the lubrication. The thinner, the stronger the adhesion. As for the shape of the interface and quantity of water, together these factors ... | [
"You've described the two phenomena the OP asked about, but haven't said why sometimes the one predominates and sometimes the other..."
] |
[
"How do antibodies from breast milk end up in a baby's immune system, travaling trough the mouth, saliva and gastric acid?"
] | [
false
] | null | [
"Firstly, you are right to infer that antibodies should be denatured by the low pH in the human stomach. Feeding an adult human antibodies would do nothing as they would be denatured and rendered useless in the highly acidic stomach. Neonates have a much higher stomach pH than adults - during feeding the pH is arou... | [
"Yup that is also true! The mother has circulating IgG antibodies that she has produced in response to vaccination against a specific antigen. Some of these are transferred in breast milk. I just found a ",
"quora post",
" that explains maternal antibodies much better than I can"
] | [
"Hmm...",
"My understandig is that vaccinations in the mother also protect the baby durring breastfeeding but not after.",
"I cannot wrap my head around it to be honest."
] |
[
"What would happen if a neutron star merged with a super massive black hole?"
] | [
false
] | Two of the heaviest objects in the universe. What would happen if they orbited each other, Collided, & merged? I feel like obviously gravitational waves will be detected, but would a new element be detected? | [
"Neutron stars are dense, but they aren't actually all that heavy compared to some other stars. Neutron stars are less than 3 times the mass of our sun, and we know of stars that more than one hundred times heavier than the sun."
] | [
"It will just fall in and disappear, emitting some gravitational waves before."
] | [
"No new element. And as big as a neutron star might be they are smaller than a black hole. In fact there are regular stars more massive than neutron stars. So it would be a smaller interaction than two black holes merging. "
] |
[
"Can double planets form in a star's habitable zone and have an earth-like atmospheres?"
] | [
false
] | I know that double planets are rare, but we have spotted a rouge double planet where one body has a mass of roughly 7 Jupiters and the other has a mass of roughly 14 Jupiters. In addition, we have a solar double planet in out own solar system (Pluto and Charon, though I realize its status as a double planet is open to... | [
"Yeah, there's nothing that prohibits it from occurring, although it would be fairly difficult to achieve such a system. Generally during the primordial formation of a protoplanetary disk, there's very little chance that two planets of ~earth mass would form in the same orbit and become a double planet system. Rath... | [
"Perfect! Unlikely is fine, as long as it's possible.",
"Could they form when a larger planet is forming and something acts to tear the proto-planet in two? Or would something with that much force just knock matter out of that orbit?"
] | [
"Well, it's pretty difficult to tear a protoplanet in two. Earth was probably hit by a roughly Mars-sized body early in its history, and the ejecta from that collision collected in orbit and formed the Moon. But the Moon is much less massive than the Earth (about 1% of the Earth's mass). If you had enough impact en... |
[
"Does getting in shape before having a kid change the child’s genetics/shape?"
] | [
false
] | Let’s say I wanted to have kids with somebody in 6 months. If I hit the gym hard, built my stamina and lean muscle mass a lot during the 6 months, would my child be more likely to be in shape than if I hadn’t done that? What about other factors like tanning, would their skin be more tan if I were tan? If the answer is ... | [
"While the vast majority of the baby's characteristics will be determined genetically, there is growing evidence that some characteristics can be altered epigenetically in the womb.",
"Basically, your DNA is the instruction manual for your cells to make stuff, but it can be chemically modified based on your envir... | [
"You are wrong. The influence of parental fitness on fetal epigenetics is an extremely active field of research. For example, I've got a friend who looks at behavior and morphological alterations in offspring of obese vs low body fat monkeys. Not only do the offspring of obese monkeys themselves have increased bod... | [
"I agree that improved physical fitness plays a role in forming healthier offspring during embryonic development. ",
"However my answer was based on what the OP is asking; the child's overall 'phenotype' would not be altered if the parent were extremely fit (i.e. high muscle mass) in relation to the parent being... |
[
"What are the arguments for and against viruses being considered living things?"
] | [
false
] | [deleted] | [
"Arguments can be made that they are \"alive\" because they reproduce by replicating their genetic information (either DNA or RNA depending on the virus). They are completely dependent upon a host cell in order to replicate their genetic information but so are many species of parasites that are considered to be ali... | [
"Most of what I've learned designated viruses as not being alive, so I know that side better. To my understanding, part of the debate comes from how we did not understand exactly what viruses were for a long time.",
"Cell theory does not support viruses being alive. It's more like a protein coat surrounding DNA o... | [
"One problem with this definition is that unicellular obligate parasites also cannot replicate without a host cell, but are considered living based on cell theory."
] |
[
"Does watching ourselves in the mirror activate mirror neurons? Would doing an activity in front of the mirror influence learning in that case?"
] | [
false
] | null | [
"Yes, and you can conclude that the answer is \"yes\" without having to run any expperiments:",
"Because if you are able to recognize that something you've done with your hand and the thing that you see in the mirror are the same sort of thing, then by logical necessity, you MUST have been activating some neuron,... | [
"I would like to get at least a master's in psychology one day, do you have any tips for me like where to study, how to not manipulate indirectly my circle of friends?"
] | [
"Almost everywhere has a psychology program. For really good ones in undergrad, the various publications put out every few years for college rankings of departments are usually accurate enough for ballpark (if you haven't already done undergrad).",
"When it comes to grad school rankings being meaningful depends o... |
[
"Why are spinal discs so prone to hernias?"
] | [
false
] | [deleted] | [
"To add to other comments:",
"L5/S1 is particularly prone to injury because the disc is situated along a steep slope just above the pelvis, and so it carries the weight of the torso not squarely on its face like all the other discs, but at a fairly steep grade. Additionally (and this is true throughout the spine)... | [
"Hmm I've must have struck a nerve.",
"Because chiropractic has no place in ",
"/r/askscience",
" as a source. The theory underlying it is anything but scientific, and the studies that are published are riddled with methodological flaws like failing to control properly for bias, leading to false positives. Th... | [
"Hmm I've must have struck a nerve.",
"Because chiropractic has no place in ",
"/r/askscience",
" as a source. The theory underlying it is anything but scientific, and the studies that are published are riddled with methodological flaws like failing to control properly for bias, leading to false positives. Th... |
[
"If deadly diseases were completely successful and killed everything, would they die out? And in that case what is the point of them being deadly, why is it worth risking to run out of the source of their lives?"
] | [
false
] | null | [
"That's the point though - evolution is not a conscious process. It's not as if an organism decided \"I want to be resistant to this drug\" and made the changes to do so."
] | [
"This is like asking \"why does a fire burn itself out - what's the point of using up all the fuel if it can't sustain itself?\"."
] | [
"Viruses and bacteria don't have a goal, they aren't sentient. Diseases that are successful in multiplying and spreading will do so without regard to whether or not they're depleting their 'food supply'. They don't try to kill their host, they just multiply and killing the host is just a side effect of that. "
] |
[
"What are the major unanswered questions of biology?"
] | [
false
] | null | [
"This is definitely a biased list, especially since it's a Wikipedia page that's subject to anonymous editing. Multiple reason exist to why the pages are so disparate, but I'll save that argument since it leads nowhere.",
"I would argue that biology has TOO many big questions, especially since so many of them are... | [
"I notice abiogenesis isn't there.",
"Maybe biologists just aren't as whiny?"
] | [
"A few on Wikipedia",
"."
] |
[
"How do they capture and separate gases? Which are more valuable due to processing?"
] | [
false
] | ...like bottling oxygen, argon, nitrogen, helium, etc. I was curious which processes are involved in drawing these from the atmosphere and storing. I was wondering specifically about Nitrogen -if it makes a big enough difference. Thanks | [
"Nitrogen, oxygen, and argon are made in bulk using cryogenic distillation of air. Basically, they cool down and compress air (like the kind we breath) until it liquifies then run it through a distillation column, nitrogen off the top, oxygen almost the bottom, argon the bottom.",
"Helium is found predominately ... | [
"You are correct, PSA and membranes work for small scale. I did state bulk (large scale) in my first comment. LNG is cooled to -162C, coincidentally around the same temperature as N2 which is why I figured they liquify the natural gas to capture the helium. ",
"If you are ordering a bottle or dewar of N2, O2, ... | [
"Most gasses are separated through cryogenic distillation, a type of fractional distillation.\nThe gasses are filtered of particulates and hydrocarbons then super cooled to a liquid state. The temperature is raised and the pressure lowered to cause the gasses to vaporize at different stages allowing for separate co... |
[
"When animals leave their parents to establish their own lives, if they encounter the parents again in the wild, do they recognise each other and does this influence their behaviour?"
] | [
false
] | I'm thinking of, for example, eagles that have been nurtured by their parents for many months before finally leave the nest to establish their own territory. Surely a bond has been created there, that could influence future interactions between these animals? | [
"In domestic felines, it’s documented that daughters may share or overlap territories with the mother. Some even share a nest. This to me shows they do recognize one another, as outsiders are generally not tolerated. How much they tolerate one another varies, but they do tend to tolerate familiar cats more. It’s n... | [
"Elephants are known to have strong recognition skills. They can remember other members of the group that aren't relatives.",
"Heck, they even remember the graves of other Elephants that they never even met. They have great memories and a strong sense of family/extended family groups.",
"Ethologist Cynthia Moss... | [
"In dogs the generally accepted explanation is that they have a \"scent memory\" and when a scent is matched they will feel safer and more comfortable with that other dog. This means that dogs will remember their parents and siblings but not in the same way as humans. Dogs just have a list of dog smells they like a... |
[
"Quantum entanglement and black holes question."
] | [
false
] | After reading a few discussions on here and an recent news article on quantum entanglement, I'm left with a puzzling question that I'd like a little help with. Suppose you devise a craft that could enter the event horizon of a black hole and stay in a relatively stable orbit once inside. This craft could have whatever ... | [
"There are three unresolvable problems with your thought experiment.",
"The first is that useful information cannot be conveyed through singlets, which point has been made already by others.",
"The second is that stable orbits inside black holes are impossible. Even \"relatively stable orbits\" inside black hol... | [
"That ",
" article has gotten a ",
" of flack. It's pretty terrible, really.",
"There can be no causal relationship between events with spacelike separation. That's the complicated-sounding underlying truth that explains why it's not possible to transmit useful information faster than the speed of light by an... | [
"In the reference frame of the stationary observer, there's a time-dilation divergent singularity at the event horizon. Time stops. In the reference frame of the infalling observer, infinite time in the rest of the universe passes before the event horizon is reached."
] |
[
"What would happen if you took way too much LSD? I'm talking hundreds of times more than your optimal dose."
] | [
false
] | What would be going on in your brain at this moment? Would you ever recover? | [
"Funny story, this actually happened once. Some people were trying to do cocaine and ended up snorting LSD. As LSD is much active than cocaine, they ended up taking a couple hundred fold dose over what they should have.",
"From \"Klock JC, Boerner U, Becker CE. \n“Coma, Hyperthermia, and Bleeding Associated with ... | [
"So... you will probably die or suffer other severe consequences if you do not get immediate medical attention."
] | [
"Yes, but if you took close to three thousand times the regular dose of almost any other drug, including aspirin and other over the counter drugs, you'd be a goner for sure. You definitely wouldn't be good within twelve hours. "
] |
[
"What are some potentially life-changing technologies that are currently being researched and should be viable in the next 20 years?"
] | [
false
] | What I'm looking for are research projects that have the potential to change the way humans live -- for the better. Full-sized cities that use only renewable energies, transatlantic or transpacific high-speed trains, and new world-wide networks that offer significant benefits towards advancing the human race (i.e., not... | [
"Non-invasive brain stimulators(like TMS and tDCS machines) have been improving in price and safety steadily over the last decade or so, and will probably ",
"start to enter the consumer market",
" as \"cosmetic neuroscience\" devices(devices which are used on healthy people in order to enhance or modify some a... | [
"we might finally understand the microscopic origin of ",
"http://en.wikipedia.org/wiki/High-temperature_superconductivity",
" and then use the knowledge to manufacture superconductors at room temperature! This would lead to to lossless energy transmission, maglev trains, flying cars, etc."
] | [
"If Artificial Intelligence ever takes off in that it successfully starts programming and building itself -- and exponentially greater speed -- it might have very well life-changing effects... see ",
"Technological Singularity",
". (Whether that's for the better or not is a different question, and I guess we ma... |
[
"Is our peripheral vision slower than our \"main focus\"?"
] | [
false
] | I've noticed many times if I'm looking at something like 2 TVs on the same channel I feel like the one in my peripheral is delayed enough to be noticed. Is this real and if so what causes it? | [
"I'm not sure if the peripheral section of your eyes receives any information slower than the main part, but the peripheral section is better at searching for movement and the difference in contrast (light to dark). Our peripheral vision serves as a safety feature if you will, to warn us of small changes in colour ... | [
"The signals arrive in the early visual brain areas at the same time and takes around 60ms (which would be too fast to notice any small differences anyway). \nThe slowed perception you describe could be attributed to differences in processing along the visual pathway. The information you receive in your fovea has m... | [
"No, all vision (peripheral and central) travels at the same speed, as sight is conducted along the optic nerve. However, your focal point- the direction you're facing- will be more detailed and specific so to speak. This is in contrast with peripheral vision, which is mostly attuned to detecting movement and whatn... |
[
"Does the standard model predict 12 different gauge bosons?"
] | [
false
] | Does the standard model predict 12 different gauge bosons? | [
"Depends how you count them, but yeah: 8 gluons, W",
", W",
", Z",
" and photon"
] | [
"Yes. The mathematical reason is that SU(n) has n",
" - 1 independent generators (one less because of the traceless condition), and U(1) has one generator, so the Standard Model gauge group SU(3) x SU(2) x U(1) has (3",
" - 1) + (2",
" - 1) + 1 = 12, which means there are 12 gauge bosons.",
"EDIT: for compl... | [
"Yes."
] |
[
"Does it matter if cooking denatures proteins in food if our bodies were going to break them down anyway?"
] | [
false
] | A relative of mine has gotten into the Raw Food trend. The main premise is that cooking and processing denatures proteins and reduces the nutritional quality of the food. But if our bodies break proteins down anyway, to what extent should it matter? | [
"It's my understanding that the word denaturize means to take from its primary state. The amino acids are still preserved. Also many proteins can be renaturized. Actually, the cooking process can sometimes make it easier to capture nutrition through denaturization. See: bioavailability. "
] | [
"You're not wrong about the proteins, but the problem with the premise is that a food's nutritional quality is not only determined by proteins. For example, vitamin B9, vitamin C, and vitamin B1 are all unstable at high temperatures and can be denatured during cooking. Theoretically, the loss of these components ... | [
"And of course stuff like beta-carotene is more easily absorbed after cooking."
] |
[
"Is it currently technologically possible to clone homo neanderthalensis?"
] | [
false
] | We all know why we would clone them, they are the closest related species of primate to our own, we would clone them to study them in order to get a better understanding of the hominid family of apes. Blah blah blah morality something something or rather... Im not interested in philosophy, only science, so please dont ... | [
"Side question - how many decades away is the technology? Constructing an artificial genome and then packaging it properly and all that jazz seems awfully complicated, too complicated.",
"I imagine it'd be easier (or maybe both options are equal in terms of sci-fi-ness?) to just mutate an existing human genome a... | [
"Sorry, but what is your source on this? It would appear that this was achieved in 2007.",
"This article",
" from the BBC states that primate cloning has been performed successfully, and that human cloning is feasible:",
"A team in the US created dozens of cloned embryos from a 10-year-old male macaque, the ... | [
"as mentioned in the top comment, just mutating a human cell won't do. The way the nucleotide sequence expresses itself is as critical as the particular sequence. But since the expression patters (epigenetics) of neanderthals are not known, you won't be able to produce a \"real\" clone."
] |
[
"How can fish tell up from down underwater?"
] | [
false
] | [deleted] | [
"I'm not sure this is a legit answer. Many fish have no swim bladders, such as fish that rapidly surface Tuna is an excellent example. I believe that the otoliths found in the fish's skull are under the influence of gravity and help fish orient themselves."
] | [
"Fish orient themselves by use of otoliths found in their skull. They are basically small bones that float inside of a structure in their inner ear called the saccule. Inside of the saccule there are sensory cells that are stimulated when they touch the otolith. So if a fish is upside down it knows it is upside dow... | [
"Fish have organs called swim bladders which keep them floating upright depending on the pull of gravity. Think of it like a balloon attached to a weight, the weight is always going to be on the bottom and the balloon on top under water. Fish can swim upside down, but only for short bursts, otherwise their swim bla... |
[
"Why do we instinctively tilt our heads back (nose up) when we're in total blackness?"
] | [
false
] | null | [
"I dont know this at all but ill give it a shot, probable because we look for the absolute light in the sky which is the sun? Dont take my answer seriuosly"
] | [
"There was no chance of that. =)"
] | [
"Well no you instinctivly look for the sun or ceiling light "
] |
[
"Antimatter"
] | [
false
] | [deleted] | [
"Well to be a bit more specific, the universe created matter and antimatter ",
" equally. For reasons we're not quite sure of yet, it favored matter production by some tiny amount. And thus the universe is a lot of empty space filled with photons, and a few clumps of \"matter\" here and there.",
"But the matter... | [
"Its an interesting idea. But the problem is that the annihilation and creation you are talking about aren't 'events' that happen seperately from one another, they would happen continuously, all the time. ",
"Because of that, your idea of using the probabilistic nature of quantum theory to explain the current asy... | [
"No, it's called asymmetry. Antisymmetric objects are actually a lot like symmetric ones, it's just that instead of getting an identical configuration under your symmetry transformation, you get a configuration that is the opposite in some sense. (Often a sign flip.)"
] |
[
"Can I get an explanation for a case that a friend claims exemplifies a link between vaccines and autism?"
] | [
false
] | [deleted] | [
"He later got his vaccinations, which she claims coincided with a sharp fever, requiring hospitalization, after which he was diagnosed with low-functioning autism",
"One of the reasons the suspicion that vaccination is linked to autism persists, is that the age at which autism symptoms begin to emerge coincides w... | [
"Most concisely: anecdotes are not evidence. Coincidences happen, and statistical analysis is the backbone of science.",
"Pretty much every infant has a high fever at some point.",
"Going to a hospital is a good way to get diagnosed. He might very well have been diagnosed the same if he had gone in for an ear... | [
"Yeah, this is a hard one. When vaccinating so many people over a limited time window you will get perfect correlations like this. The only way to determine causality is through large randomized trials, which have been done showing there isn’t a causal link. ",
"But it sucks. We really want explanations for devas... |
[
"Is there any possible evolutionary advantage for a man to raise a child that is not his own?"
] | [
false
] | I'm talking specifically about a man taking over the father role in the life of a child who has a single mother. Couples who adopt are excluded from this question. It happens often enough but I don't see how this situation would be evolutionarily advantageous to the man, unless it has something to do with securing a fe... | [
"There are many examples of traits which have developed which are detremental to the individual, but beneficial to the species. There are insects which will commit suicide in order to protect the hive.",
"Remember that evolution when it comes down to it is all down to chance. A creature with beneficial traits is ... | [
"There are many examples of traits which have developed which are detremental to the individual, but beneficial to the species. There are insects which will commit suicide in order to protect the hive.",
"Hives are genetically similar. Therefore the insect when dying is protecting its genes. "
] | [
"The altruistic nature of humans had to come from somewhere, and certainly evolved, through memetic or genetic evolution (almost certainly both). It cannot be an explanation for behavior, it itself must be explained in a more scientific, more a-priori manner. You cannot plug in 'altruism' into a model for the game ... |
[
"What would happen if you fell into Jupiter?"
] | [
false
] | [deleted] | [
"You'd be blown about a lot by winds/currents, fall until you reached a cloud layer at your approximate density, and then stop sinking and get blown around some more."
] | [
"Jupiter creates a fair bit of energy due to the nuclear reactions at its core",
"Most of Jupiter's heat is from contraction after its formation. The role of radioactivity from its core is relatively insignificant. It has been calculated that 1 m of contraction could generate all of Jupiter heat. Additionally, J... | [
"Indeed, I'd forgotten about that. A probe with the ability to survive deep enough to gather useful new data, and then either have a transmitter powerful enough to beam its discoveries back out through the atmosphere or a way to re-ascend. Unfortunately that's rather a pipe dream the way our space program is going.... |
[
"When you rub something to create static electricity, how do the electrons decide which side to stick onto?"
] | [
false
] | null | [
"I'm assuming by \"side\" you mean which object will be positively charged (lost electrons) and which will be negatively charged (gained electrons). ",
"Regardless, what causes objects to gain a charge when rubbed is known as the ",
"triboelectric effect",
". I can try to explain some of the stuff in the arti... | [
"When you bring two objects into contact, the surface charges are free to move around and distribute themselves however they want depending on a number of factors including how many are present on each surface and each material's electron affinity. Once these charges distribute themselves, when you separate the obj... | [
"Please go on about the cause behind the triboeletric effect. According to Wikipedia, all it says is that electrons move to balance \"eletrochemical potential\"."
] |
[
"What \"part\" of the Milky Way are we seeing when we look to the sky on a perfectly clear night?"
] | [
false
] | Is there a map of the Milky Way that points out which part of our own galaxy we are seeing in the sky? Thanks! | [
"It depends on where you are looking! For example, if ",
"this is your view",
", you're looking towards the center of the Galaxy, towards the bulge (bright thing in middle of the image) and the inner disk (flat bits). At a different time of the year, you'll only be able to see different parts of the disk of the... | [
"As stated by ",
"/u/tvw",
", during the Northern Summer, we can see the Galactic center at night. During Winter, we look away from the center out towards the edge of the galaxy (anti-center) at night (the center is blocked by the Sun's brightness at this time.)"
] | [
"http://cdn.c.photoshelter.com/img-get2/I0000emC9PgICU_8/fit=1000x750/Winter-Sky-from-Home-15mm-5DII.jpg",
"It's more or less the same but fainter with less dark, dusty structure.",
"Edit: Also, bluer."
] |
[
"What in our brains causes feelings of hopelessness associated with suicide?"
] | [
false
] | What about depression causes people to have the "hopeless" feeling that pushes so many people to suicide? Why don't we feel this while we're happy and why would our own brains be so easily led to killing itself despite the common belief while happy that suicide doesn't make sense? | [
"Depression likely has something to do with serotonin. The most common treatments are SSRIs, which increase levels of serotonin in the brain. ",
"That said, mechanisms behind depression aren't fully understood. There are likely significant psychological factors as well. "
] | [
"Interestingly, many people who have died by suicide were found to have low levels of serotonin detected through CSF sampling. I'm not suggesting that serotonin is the only thing implicated in depression, but it may play an important role in knowing what pushes people to suicide. "
] | [
"You should use the term \"depression\" as the thing the brain chemistry might be driving, rather than suicide. Depression is a long term irrational mental disorder, suicide is a behavior. You could commit suicide due to depression, but you could also commit suicide for rational reasons (let's not get too much into... |
[
"There are no known incidents of the endangered African wild dog (Lycaon pictus) attacking humans in the wild. Why would this be, given their reputation as ferocious hunters?"
] | [
false
] | null | [
"In the case of wild dogs, the ferocious reputation doesnt have to do with them attacking anything and everything, its due to the way they kill their prey being fairly gory (usually disembowelment). In general most predators don't attack humans that often, because of the fairly small amount of food on us, and the f... | [
"What evidence are you after? Im sure they have attacked humans in the past, it just wasn't necessarily recorded. "
] | [
"That's about as close to an answer as you'll get. You may also have incomplete sources. What we can probably say is that since exhaustive records have been kept on animal attacks on humans in Africa in a format that that might be digitized or otherwise make their way online, there have not been any attacks. If an ... |
[
"Would the antibodies from the pfizer covid-19 vaccine produce a positive on a covid-19 antibody test?"
] | [
false
] | Since the pfizer vaccine doesn’t use any virus cells but altered RNA to mimic the virus’ spike protein, would the antibodies produced from the vaccine show up on a covid-19 antibody test? | [
"Generally, we would think yes, and this is what happens for most vaccines. Antibody tests aren’t looking for the virus or vaccine, but instead for your body’s response to it (IgM or IgG antibodies, which your body produces to fight infection). Phase I/II of the Pfizer trial tested for IgG concentration; you can re... | [
"Thank you for the response. It has been very helpful. I participated in the trial and they obviously cannot tell me if I got the real vaccine or just the placebo, but I was curious. I did the rapid antibody test that kroger just started offering and was negative for antibodies."
] | [
"The vaccine only includes the spike protein (and only a segment of it). Viral infection will drive antibodies against many other proteins, such as NP, and there are antibody assays that test for NP as well as spike protein (",
"Review of Current Advances in Serologic Testing for COVID-19",
"). Those antibody a... |
[
"How do split depth gifs work?"
] | [
false
] | The subreddit showcasing the phenomenon under discussion: discussionhttp:// It's clear that the lines covering some parts of the gif and not others is responsible for the effect. I'm curious what about our visual system makes this effect so powerful. | [
"Your brain sees the picture with lines on top. The lines form a frontal barrier to the picture. When the line is moved to the back ( imagine layers) your brain translates the object in the picture moving toward you."
] | [
"Pictures contain several types of ",
"depth cues",
". Occlusion is one of them.",
"If object A occludes object B it only makes sense that A is in front of B.",
"When an object in a .gif file is suddenly not blocked by one of those stripes any more our brain interprets that as \"it has moved in front of tha... | [
"what would happen if you put a bunch of smaller white lines such that is doesn't interrupt the picture as badly?",
"Is there a way to double the effect into two layers? Maybe with different colored lines or something? Creating more lines and only covering some, and then the things to be closest cover all of the ... |
[
"how do dogs know that we're play fighting, and thus know not to use force/their teeth to hurt us?"
] | [
false
] | null | [
"Dogs do this with each other and if you're not hurting them they don't have a reason to hurt you."
] | [
"Yes, animals play specifically because it resembles fighting or other natural survival functions. It's a way of training for such occasions on your off time. It's why dogs enjoy playing fetch and cats like pouncing on toys. That's also why play is emotionally rewarding; if you enjoy doing things that prepare you f... | [
"Maybe he just hates the coat."
] |
[
"If we knew the complete history of one's actions, could we predict what they would do when presented a situation?"
] | [
false
] | [deleted] | [
"The way that I understand your question, no.",
"I believe that you are asking if humans are essentially deterministic programs that could be modeled accurately, if we had access to all of the necessary data.",
"The first problem is the data that you have to work with. Everything this person sees, hears, feels... | [
"and I know that we aren't supposed to speculate, but there's really no other way to respond to this."
] | [
"EDIT: I may have misunderstood the question. If the question is whether this would be possible JUST by watching what someone does, I agree with the above that this is probably impossible.",
"While I of course agree with you in terms of the practical conceivability of human technology in the foreseeable future, ... |
[
"Given enough time can we actually change the trajectory of potential dangerous asteroids etc. ?"
] | [
false
] | Are we completely helpless against large asteroid and other potentially dangerous bodies or can we blast them off course given enough time? Surely a small change in trajectory over the years can make all the difference. Also, what's the biggest body we can potentially save ourselves from? | [
"There's a nice long ",
"wikipedia article about the topic",
".",
"I'm not exactly an expert on the topic, but my feeling is that we could do it, but it would be more expensive the less time we had. In an emergency situation, one could imagine that it might spark something akin to the Manhattan Project.",
... | [
"Given enough time yes we can. In fact there are even plans if these things happen. We have landed on asteroids before as a proof of concept. The idea is we would land on an astroid and shoot little parts off of it constant. \"For every action there is an opposite and equal reaction\" Shooting these little rocks of... | [
"Why doesn't NASA try to actually divert an asteroid?",
"Find some asteroid that's not on any sort of NEO trajectory. Send up a probe there with a decent size nuke on it. Then set it off. Analyze the change in the asteroid's path.",
"There's a lot of speculation on whether nukes are effective or not. Why not ju... |
[
"What form of numeric differentiation is this?"
] | [
false
] | I needed to code up a quick check of a routine that returned the derivative of some function so I found myself doing (f(x+e)-f(x))/e as e got tiny. So far so good. Then a coworker said that in his experience (f(x+e)-f(x-e))/2e was more accurate for e > 0 because it was symmetric. I checked that in the limit e-->0 the... | [
"There are three simple ways to approximate a derivative, with different amounts of error from the \"true\" derivative.",
"d(x) = (f(x+e) - f(x))/e is called a \"forward finite difference\". Its error is proportional to e.",
"d(x) = (f(x) - f(x-e))/e is called a \"backward finite difference\". Its error is al... | [
"One other thing to keep in mind is that by choosing e too small, you will eventually run into numerical problems (due to cancellation of the floating point numbers).",
"In this case, choosing schemes which use multiple points may improve results because it suffers less from this problem."
] | [
"Oh, one more thing. It doesn't necessarily give the same (or correct for that matter) answer for every simple function. For example |x| is non-differentiable at zero, but a symmetric derivative will give you a result of 0.",
"Practically all methods of numerical integration will give results even in non-differen... |
[
"How did we discover that a vacuum is not really \"empty?\""
] | [
false
] | I don't understand it, and from what I've read, no one really does. But we know that a vacuum in space is not the same thing as "nothingness" and that there is a Higg's field everywhere. I could be way off, but my understanding is that particles and their anti-particles snap into existence and then instantaneously can... | [
"One of the direct ways of observing the vacuum is via the so-called ",
"'Casimir Effect'",
". When two metal plates are placed close together they prevent long-wavelength (low-energy) virtual particles from being created in the space between them, so there are more virtual particles outside the plates and thi... | [
"If you are familiar with the uncertainty principle, this will be easier to understand. So, I'll make the assumption that you are - if not, ask me and I'll tell.",
"The commonly known form of the uncertainty principle has to do with momentum and position. If you try to fix a particles position too accurately, the... | [
"To my understanding, this is not the case. The uncertainty in momentum doesn't stem from the method of measurement. It takes place even if not measured.",
"A good way to think about this is to realize that particles can behave as both waves and particles (I get that they don't behave like two different things an... |
[
"How can one side of Mylar film be reflective, while the other side is transparent?"
] | [
false
] | [deleted] | [
"Transparent? Maybe you're thinking that one side is reflective and the other side absorbs light. ",
"Two way mirrors work by transmitting 50% of incident light and reflecting the other 50%. They only function as a 2 way mirror when the secret viewing side is in a dark room."
] | [
"The mylar film reflects light equally in both directions, but there isn't an equal amount of light coming ",
" both directions.",
"Let's say we have some mylar that reflects 90% of the light that strikes it, and one side is in daylight and the other is indoors. Indoor lighting is roughly 100 times less bright... | [
"Both sides are as transparent as each other. One side may absorb more light than the other, or reflect it more diffusively, in which case it may appear to be more transparent as the brightest coherent light is the light that comes through from the other side.",
"\"Two-way\" (even the name is weird, shouldn't it ... |
[
"Can neutron stars spontaneously turn into black holes?"
] | [
false
] | I know that if a star over a certain weight threshold explodes, it turns ino blackhole immediately, but what if it's just barely underweight? What if it hits a bigger planet, or another star? | [
"Yes, a neutron star ",
"can collapse into a black hole if it gathers additional mass from a companion star",
". Also, a rotating neutron star can be slightly over the critical mass without collapsing, and when its rotation slows down enough it can then collapse. ",
"It has been suggested that this is the cau... | [
"Could passing gravitational waves cause a collapse with no extra mass being added?"
] | [
"OP also included a question about what happens if it hits a planet or star."
] |
[
"What are some recommendations for good layperson-friendly books about space, theoretical physics, and other mind-benders?"
] | [
false
] | Firstly, I apologize if there's a better subreddit for this. I've been interested in this sort of stuff my whole life, from being 7 and getting my mind blown by reading kid astronomy books to (now) getting my mind blown by reading space and science subreddits, and so forth. I want to keep digging, but I took a liberal ... | [
"While I'm not a fan of string theory personally, I do like Greene's Fabric of the Cosmos as a really coherent explanation of the structure of space-time and the ideas that form our current understanding of the big bang."
] | [
"Read The Discoverers by Daniel Boorstin."
] | [
"It's old, but \"A Brief History of Time\" blew my mind years back. "
] |
[
"If you fired a minigun into the air and had a strobe light next to it, timed to the rate of fire of the gun, would you be able to \"see\" a bullet \"suspended\" in mid-air?"
] | [
false
] | I'm wondering if you could perform an experiment like "time fountain" except instead of drops of water, use bullets from a cannon like Warthog gun. Put a very fast strobe light next to it. Could you see the round coming out of the gun? | [
"Timed properly you absolutely should. \"Timing lights\" are used in tuning cars. Set properly the light strobes at a rate that will illuminate the same spot on an engine belt each time it passes (I've just put a piece of masking tape on the belt). The GAU-8 fires from a given barrel while it is in the 9 o'clock... | [
"I like turtles."
] | [
"Expanding from that, with a muzzle velocity of 3500 ft/s and max ROF of 4200/min that means those 70 rnds/s are leaving the muzzle 50 feet from each-other."
] |
[
"When a neutrino oscillates in-flight into another neutrino, how are its energy and momentum conserved? (It seems that no matter how the speed changes, both can't be conserved at the same time if the neutrino it turns into has a different mass?)"
] | [
false
] | null | [
"The neutrinos are produced in flavor eigenstates which are superpositions of the mass eigenstates. They are not produced in energy/momentum eigenstates. You can describe the propagation as three independent mass eigenstates doing their own thing with different speeds, but if you want to look at further interaction... | [
"You can see them that way for the propagation, yes."
] | [
"With some caveats: Yes.",
"https://arxiv.org/abs/0810.4132"
] |
[
"Lasso the moon thought experiment"
] | [
false
] | null | [
"The moon's orbit is slightly elliptical, varying by about 4300km from apogee to perigee.",
"So if the length of your tube represents the moon's average distance, the end will alternately be 2150km above or below the earth's surface. That is a third of the way to the center of the earth.",
"What's more, the mo... | [
"The Earth rotates 360",
" per day, while the moon rotates the Earth in the same direction at about 13.2",
" per day. This means the moon is in approximately the same spot in the sky every 24.8 hours.",
"The circumference of the Earth is actually a little bigger at 40000km, so the tube would move across the E... | [
"I didn't even consider that, actually. Derp. Thanks for pointing it out."
] |
[
"Would it be possible to artificially myelinate axons?"
] | [
false
] | I'm pretty new to neuroscience, but is this possible? Has it been done? Is it possible outside of the body? What about actually in the body? | [
"From what I've heard this is not yet possible. Generally once the Schwann cells (PNS) or the oligodendrocytes (CNS) that form the myelin sheaths are damaged, there is no repairing them.",
"This is the mechanism of Multiple Sclerosis which is the body recognizing and attacking these sheaths. Treatment for MS is m... | [
"Not even in vitro? "
] | [
"Not that I am aware of, I was doing research in this area two years ago and there were a few projects that were promising for restoring nerves damaged in spinal cord injuries but I am not familiar with any projects that have been successful in remylinating axons."
] |
[
"[Biology]Why did the majority of animals evolve with two holes for excrement, one located on genitalia?"
] | [
false
] | I was thinking about this, it doesn't seem to make sense that genitalia have a secondary function as waste pipe, considering that from an evolutionary standpoint they already have one of the most important roles in the body. | [
"1) Lots of things in biology don't 'make sense' - evolution doesn't work that way, it simply selects for traits that facilitate successful reproduction; there is no design component.",
"2) Keep in mind that urinary 'waste' and gastrointestinal 'waste' are two fairly distinct entities.",
"Stool is mostly just t... | [
"Number 4 is bang on. ",
"The problem with \"why did this evolve\" questions is that there is a really large chance that the answer is just \"because that's what happened\" and there is no logical just so story.",
"One of my favourites of these is something that came out of the work done by the Russian who bred... | [
"I have a reference for you - National Geographic March 2011",
"http://ngm.nationalgeographic.com/2011/03/taming-wild-animals/ratliff-text"
] |
[
"Does i^i have a fixed, real value?"
] | [
false
] | Given that you can use the identity e = cos(x) + isin(x) to prove that i is real (by letting x=pi/2 and raising both sides to the power of i) that would suggest that i = e however since there are multiple values of x which could work just as well (5pi/2, for instance) and these would give different values, does i have... | [
"What you're seeing is called a ",
"multi-valued function",
", and they come up a lot in complex functions. What we typically do is pick the interval we want to work in a stick with it. Since we usually work in [-pi, pi], i",
" is usually a little bit more than a fifth. In different regions, it can have di... | [
"You're off to a good start.",
"Because pi/2 added to any multiple of 2pi (pi/2, 5pi/2, 9pi/2) will work, we can write it as pi/2 + 2pi*n, with n = 0, 1, 2, 3, etc.",
"So for n=0:",
"e",
" = cos(pi/2) + isin(pi/2)",
"e",
" = i",
"e",
" = i",
" (put both sides to the power of i)",
"e",
" = ... | [
"In some contexts, square root refers to the single-valued function on the non-negative real numbers. The post above, however, is specifically discussing multi-valued functions of the complex numbers. Since the square root of the complex numbers is the standard first example of such a function, it is reasonable for... |
[
"Why are there many different types of fuel (87, 93, diesel) and why can certain machines take only one type?"
] | [
false
] | null | [
"First, between different fuel types, premium gas, regular gas (87,93)",
"Basically, the cylinders in each engine compresses the fuel/air mixture to a certain amount, the more compressed the mixture, the hotter it gets and more likely it is to explode.",
"however, sometimes, if the fuel explodes before the corr... | [
"For those interested, rape oil, or rapeseed oil, is commonly referred to as canola oil."
] | [
"In most modern applications they are not interchangeable, but old military multifuel engines would basically run on anything flammable (though in practice, they were rarely run on anything besides their optimal fuel)."
] |
[
"If a neutron star is as dense or more then an atomic nucleus can it be considered one giant atom?"
] | [
false
] | I was just reading the article and it was discussing the density as greater then that of an atomic nucleus. Considering that the star is made of uniform nucleons would it be a nucleus? Edit: Thanks guys :P | [
"No. Atoms are specific things with specific properties, that behave in specific ways. Neutron stars (or as is more fashionable, \"neutron-degenerate stellar remnants\") have none of the properties of atoms, nor do they behave anything like atoms."
] | [
"Neutron stars (or as is more fashionable, \"neutron-degenerate stellar remnants\")",
"Yeah, no one calls them neutron stars anymore. That would be so square."
] | [
"Actually, theres some question about whether regions near the core are made of nucleons or whether the individual nucleons \"melt\" away into quark matter. We just don't know for sure what the phase diagram of QCD looks like.",
"More ",
"here"
] |
[
"What is the standard Hilbert space for a spinless particle moving in 1D?"
] | [
false
] | I am trying to learn QM as rigourously as possible. When trying to learn what the Hilbert space (H) associated with one spacial degree of freedom is, I found two answers: 1) It is the completion of the subspace of continuous everywhere differentiable functions on R that are square integrable. 2) It is L2 (R) (taking th... | [
"(1) and (2) are the same space (assuming, of course, that in (1) we mean the completion under the L",
" metric). The Dirac delta function is not an element of L",
", but rather an element of the dual space of smooth, compactly supported functions."
] | [
"Could you expand on why the delta functions are in the dual of functions that have necessarily compact support? (why not just the smooth, square integrable functions)",
"Also, if I understand correctly, one can consider a vector space as \"embedded?\" in its dual. In that sense, is the dual of the space of conti... | [
"Ballentine's Quantum Mechanics book does a decent job of covering this for physicists. That is, without going too deep in measure theory and functional analysis. "
] |
[
"How does CRISPR actually work?"
] | [
false
] | null | [
"Not clear what your question is. No one says CRISPR corrects all your cells."
] | [
"That's exactly me question. How does it work if doesn't correct all of your cells? If you only correct some what is the advantage?"
] | [
"Suggest you rephrase to make your question clear and repost"
] |
[
"What is \"Imaginary Time\" exactly?"
] | [
false
] | I was reading up on science fiction lately, and I came across Steven Hawking stating that he would like to read a science fiction novel or short story about imaginary time. Hawking said that no one has written one about it because they don't get it. What is it in simple terms? | [
"Borrowing from my ",
"answer in another thread",
": ",
"There are two contexts in which imaginary time is used, although it is hard to picture why things work the way they do in either context without the mathematical technicalities.",
"Hawking introduced imaginary time into cosmology as a way to remove th... | [
"If you're suggesting that it is just ad hoc and poorly motivated, then I might have to disagree. ",
"The mathematical entity that underlie the evolution of quantum states in time (the \"time evolution operator\") is mathematically well defined for real time and for negative imaginary time. If one then checks ... | [
"Sounds like it could be a good sci-fi hook to justify time travel, perhaps.",
"Is imaginary time an orthogonal dimension to regular time the way a complex number has an imaginary component (like a moment defined as t1 + t2i), or does it replace the existing arrow of time with an extended concept?"
] |
[
"Why does biting into foil hurt like hell if you have filings?"
] | [
false
] | null | [
"While I know why this happens, I don't know enough about physics/chemistry terminology to know that I'm calling things what they are correctly.",
"That said, the metal in foil and metallic fillings have different electric potentials, so electrons can move between them. Metallic fillings can get these extra elect... | [
"Yea this is correct. The \"new\" white fillings don't have this electrical problem. "
] | [
"Essentially, the metal in the dental fillings when combined with the metal in the tin foil creates a voltaic battery, with your saliva as a salt bridge. That is to say, exactly what has already been iterated by MynameisB, so I won't repeat his comment. Depending on the particular amalgam used in the fillings thems... |
[
"On the back of my cooking salt, \"Sodium FerroCyanide\" is listed as an ingredient. I've heard Ferrocyanides are safe except in the presence of acids when they give off Hydrogen Cyanide gas. If I cook with this salt and acidic foods or sauces, am I slowly poisoning myself?"
] | [
false
] | null | [
"There are two factors at play here.",
"One is that the cyanide-iron bond in ferrocyanide salts is very strong, and it takes extended treatment with strong acid to liberate cyanide ion in any appreciable quantity. Even straight lemon juice or vinegar are probably not acidic enough to generate cyanide ion from fer... | [
"No, not at all. You basically need to heat it with a strong acid (like hydrochloric acid or sulphuric acid) to free any cyanide from the complex, and even if you did that there wouldn't be enough in there to poison yourself. Also, as far as I know hydrogen cyanide does not accumulate in any way, so you wouldn't be... | [
"Indeed, as cyanides (or cyanogenic glycosides) are present in small amounts in a lot of seeds and roots that we consume (like almonds, cassava, sorghum, etc...), our bodies have evolved to be quite effective at eliminating cyanide.",
"It has a half life of 10 to 30 minutes in the organism, and its secondary meta... |
[
"What is the modern consensus in Psychiatry regarding the efficacy of anti-depressants vs placebo?"
] | [
false
] | I didn't even know until recently that for at least a decade there has been something of a controversy over whether the effects of anti-depressant medications on depression can be chalked up entirely to placebo or not, sparked mainly by work by Irving Kirsch who seems to be on a bit of a crusade against anti-depressant... | [
"My understanding is that a fairly recent literature review (Jay something, major journal) showed that antidepressants are slightly superior to placebo in cases of severe depression but no better than placebo for mild to moderate depression. \nA prominent psychiatrist colleague of mine has come to terms with this b... | [
"I believe the study you are referring to is ",
" by Jay, C., et al. published in The Journal of the American Medical Association (",
"source",
"). The conclusion as summarized in the abstract are exactly what you said:",
"Conclusions: The magnitude of benefit of antidepressant medication compared with plac... | [
"Something else to consider is that the efficacy of an anti-depressant or a placebo is based on the average across individuals. So you could have no statistical difference between groups, but that does not necessarily mean that anti-depressants are not more effective for some people ",
" the groups. For instance,... |
[
"I hope this isn't inappropriate but I've been wondering this for a while... Why does semen make my mouth turn numb?"
] | [
true
] | [deleted] | [
"Let's keep this fact based and scientific folks. Anecdotes are nice, but that's not what people come here for. "
] | [
"note: I am not a health expert.",
"AFAIK, this reaction is simply a mild allergy or sensitivity. While a full-blown reaction to semen is rare (<2% of women), a sensitivity would be more common, as with any allergy. There is a growing body of research on semen allergies, also called human seminal plasma hypersens... | [
"Please do note that ",
"r/askscience",
" is not a replacement for your medical practitioner's advice. If you think this is indeed what you might have, please seek medical attention. ",
"I'm not trying to degrade from your statement navaboo, simply re-stating what it says on the sidebar for emphasis."
] |
[
"Are there any animal species where the male acts more \"motherly\" to its young / the female tends to act more \"paternal\" to its young?"
] | [
false
] | null | [
"Catfish dads, on the other hand, carry approximately 48 eggs in their mouth to protect them. The catfish daddy starves himself for two months during this period, to ensure he doesn't swallow any of his precious baby catfiddies. "
] | [
"Catfish dads, on the other hand, carry approximately 48 eggs in their mouth to protect them. The catfish daddy starves himself for two months during this period, to ensure he doesn't swallow any of his precious baby catfiddies. "
] | [
"Catfish dads, on the other hand, carry approximately 48 eggs in their mouth to protect them. The catfish daddy starves himself for two months during this period, to ensure he doesn't swallow any of his precious baby catfiddies. "
] |
[
"Does my gravity have an effect on objects at the edge of the universe?"
] | [
false
] | I understand that gravity propagates at the speed of light and that by using the theory of gravitation the force between myself and some object at the edge of the universe would be insanely small. But would it be small? Or would it be literally 0? | [
"Not if the the universe is still expanding faster than the speed of light. Then the observable universe will be shrinking."
] | [
"Due to cosmic inflation, there are likely objects beyond the observable universe where light will never reach. Since the speed of gravity is bounded by the speed of light, all matter beyond the observable universe will not be affected."
] | [
"The distance between two points can indeed increase faster than the speed of light.",
"If you look at the units of the phenomena involved, you will find, that the speed of light has the units m*s",
" while the metric expansion is measured in km * s",
" * Mpc",
" (kilometers per second per megaparsec) ",
... |
[
"What happens to make birth controls ineffective when you take antibiotics?"
] | [
false
] | [deleted] | [
"This is actually not the case, and is only true with a few antimicrobial agents.",
"Pharmacokinetic evidence demonstrates that ",
", including ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline. However, reduced steroid levels have be... | [
"The major antibiotic that people worry about is ",
"Rifampicin/Rifampin",
". This compound, and likely some other antibiotics, upregulates a family of liver enzymes called ",
"p450",
" which are involved in metabolizing a number of organic molecules (",
"ref",
"). Because of increased p450, the metab... | [
"another theory has to do with elimination of the gut flora, without which there is less hydrolysis of estrogen conjugates to ethinyl estradiol that would normally be reabsorbed in the small intestine. ",
"for the most part abx reducing oc efficacy is a theoretical interaction, but you can never be too safe when ... |
[
"What basis is there for the second being a universally accepted unit of time?"
] | [
false
] | Is this an arbitrary quantity, agreed upon so we can address time, or is there some physical or mathematical basis? | [
"It's not physical the same way the electron charge is fundamentally physical but there is a physical and mathematical basis when you consider the fact that the second was devised by humans.",
"One day is a natural unit of time for any living thing on Earth. Our sleep cycle and thus our life is dictated by it. It... | [
"If you're looking for a standard basis for as second, Wikipedia says a second is this: ",
"The duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.",
"But all SI units have just kinda been picked. None of t... | [
"I don't have an answer (it looks like it's been covered fairly well) but just the bit of trivia that \"seconds\" is just a shortening of the term \"second minutes\", as in the ",
" division of an hour by 60. It seems so obvious now, but it had never occurred to me."
] |
[
"Since children are growing and constantly have dividing cells, why do they have lower cancer rates than adults (who are not growing)?"
] | [
false
] | null | [
"Cancer develops when cells malfunction, and when the malfunction is not handled by the immune system.",
"Cells can malfunction for three reasons: cell was faulty to start with (genetics), cell was exposed to something that causes malfunction (a carcinogen), or cell randomly malfunctions. ",
"Of those three rea... | [
"Cancer is the result of many mutations in the cell. Our cells normally have many checkpoints and safe guards to control their growth and proliferation. A single mutation ALONE is not enough to turn a normal cell into a cancerous cell because of all those redundant safety mechanisms. However it may begin with a sin... | [
"There are 2 ways to answer this:",
"1.) Cancer occurs because cells accumulate a large number of mutations over time. Cells have many, many ways to prevent cancer, so mutations need to happen over a long period of time to disable these protective measures.",
"Pediatric cancers are not at all like adult cancer... |
[
"Did yeasts evolve from multicellular fungi, or did multicellular fungi evolve from unicellular fungi?"
] | [
false
] | Or was it lost/regained more than once? Also, were the first fungi unicellular or multicellular? If they were unicellular, what set them apart from other single-celled eukaryotes? | [
"Technically, all we can say with confidence is that the different unicellular fungi share a common ancestor with the different multicellular fungi. Whether that common ancestor was unicellular or not is a bit more tricky.",
"This appears to be a good review on the subject.",
" Yeast and related groups are mayb... | [
"In short, no. It doesn't follow parsimoniously that fungi were the progenitors of all life on Earth. For example, Fungi are eukaryotes and thus have introns and organelles. It wouldn't make sense for plants and animals to maintain these and have bacteria and archaea (mostly) lose them."
] | [
"Yes, thanks to molecular evidence we know fungi are related to all forms of life here on Earth and share a common ancestor with animals, and if you go even further back in time, a common ancestor with plants and etc.",
"We haven't found any being here on Earth that doesn't fall in line with common ancestry."
] |
[
"Do atoms vibrate faster when they are warmer because they are absorbing thermal energy and converting it to kinetic?"
] | [
false
] | null | [
"The kinetic energy of the particles IS the thermal energy...they are the same thing\n",
"http://en.wikipedia.org/wiki/Thermal_energy"
] | [
"So why exactly do the atoms/molecules vibrate faster when they are heated? (Sorry if this sounds stupid)"
] | [
"Totally not stupid, don't apologize.",
"You are adding energy to them, so they are bouncing around faster. One way to do this is to hit an atom with some kind of EM radiation (like shining a heat lamp or something), another way is to put the atoms in an environment with hotter (and thus more energetic) atoms. ... |
[
"How small particles can be produced by erosion?"
] | [
false
] | When a rock or a piece of glass erodes in the nature. What is the last particle size that can be left? Is it individual molecules or even atoms or is it much larger particles? | [
"Since no one has taken a shot at this one I'll have a go. I don't know the answer, but maybe I can provide a reference point. In materials science there are often cases where you want small particle sizes. One way to get that is by what's called ball milling. You put your material in a cylinder with a bunch of bal... | [
"This depends somewhat on the mode of erosion. Abrasive physical processes can break down clasts to anything from massive 100's m diameter boulders, to individual particulate grains down to a few microns across. Chemical erosion can break down the cement between sedimentary grains which will release the grainsize t... | [
"I think most materials smell and those could be in amounts of single molecyles.",
"It might be more interesting to ask which erosion processes cause which sized particles. For example rain might be sensitive to what amounts to a droplet that can drop. Wind might have one effect of carrying small rocks to smash o... |
[
"Can a submarine go into space/does a spaceship need to survive ocean dephs to be spaceworthy?"
] | [
false
] | [deleted] | [
"In terms of ",
", submarines have to be much tougher than spaceships. A submarines can experience many many atmospheres of pressure, but the pressure difference across a spaceship hull is going to be about one atmosphere at most. So a spaceship may be crushed in deep water.",
"The pressure difference is also i... | [
"Just adding to this, but submarines are designed for a fairly narrow range of temperatures. Ocean water would range from 32 Celsius to at the lowest just as cold as freezing sea water (-2 Celsius). Space ships are designed to operate at a wide range of temps to survive take-off and re-entry as well as the cold vac... | [
"Cooling would likely be a bigger issue in space than heating, especially for a nuclear submarine. You can only cool radiatively."
] |
[
"What does it mean that time doesn't exist in a black hole?"
] | [
false
] | My complete elementary understanding of time is that it's a human construct meant to measure relative periods between events. If time actually doesn't exist (because we've made it up simply to measure the relative distance between events) what does it mean that time doesn't exist? Do all events happen simultaneously? | [
"What does it mean that time doesn't exist in a black hole?",
"I really don't think it means much. In fact, I don't really understand \"time doesn't exist\", and I don't really understand \"in a black hole\" either.",
"If you mean \"inside the Schwarzschild radius\", then it's wrong. If you were to get close en... | [
"Time exists, it's just absolute time that doesn't exist."
] | [
"But that's the same everywhere else, right? "
] |
[
"What happens if an earth-like planet crashes into a star? Or at least fall out of orbit and start approaching it?"
] | [
false
] | Inspired by this post: | [
"An Earth-like planet crashing into its star is less like a crash than it is like a gnat flying into a campfire. The planet would vaporize as it falls into the deeper layers of star."
] | [
"Would the star flare up?"
] | [
"No, a star isn't burning so there would be no combustion-related flare like fuel on a fire"
] |
[
"How does plasma behave different from each other and also from normal fluid flow?"
] | [
false
] | null | [
"Plasma is different than a normal fluid in that it is electrically conductive, and responds to electric and magnetic fields."
] | [
"If you subject a plasma to an external electrostatic field, the free charges in the plasma will just rearrange themselves to cancel the electric field inside the plasma. There’s a phenomenon called Debye screening, where if you place a charge Q inside a plasma, rather than producing a kQ/r Coulomb potential, it pr... | [
"How does electric and magnetic fields influence flow properties? Do they have viscosity?"
] |
[
"What is a Computing Core?"
] | [
false
] | I wanna know what a core is and how it works. (Like Quad and Dual core) | [
"A core is a processor. At least in the common 'intel' usage.",
"When we say dual core of quad core processor, what we really mean is a single integrated chip (CPU) with 2 (dual) or 4 (quad) processors on it. In the old days processors were single core so this confusion didn't arise as a single core processor was... | [
"i3, i5, and i7 are all brand names. I don't think it's every been implied that they are 7-core. "
] | [
"i3, i5, and i7 are all brand names. I don't think it's every been implied that they are 7-core. "
] |
[
"Why is Deinococcus radiodurans so radiation resistant?"
] | [
false
] | [deleted] | [
"Partially because it can actually repair radiation damage. Also, the most accepted theory I ever heard had something to do with resistance to dessication, of all things."
] | [
"This page seems to have a list of the most current research:\n",
"http://www.usuhs.mil/pat/deinococcus/index_20.htm",
"From a quick read, it looks as though D. radiodurans has a two step DNA repair process where it quickly fixes strand breaks via single strand annealing then simply uses that as a template to r... | [
"This page seems to have a list of the most current research:\n",
"http://www.usuhs.mil/pat/deinococcus/index_20.htm",
"From a quick read, it looks as though D. radiodurans has a two step DNA repair process where it quickly fixes strand breaks via single strand annealing then simply uses that as a template to r... |
[
"how are there fish in a completely isolated body of water?"
] | [
false
] | Was watching one of the survival reality shows, and the dude was in the mountains, went down below the frost line, found a lake, and caught a fish.... Was it because this land was once under/near an ocean... or did some species evolve in this area to survive under water? Sorry if this is not the most well thought out q... | [
"A few possible reasons.",
"The body of water may have been connected to another at some point. ",
"Weather sometimes picks up fish, frogs, and the like and deposits them in other places. The fish who gets sucked up in a waterspout and manages to land in another body of water is very lucky, but it does happen.... | [
"I assume you mean *birds drop their catch"
] | [
"This comment should be near the top. When I spoke to many Michigan DNR officials about just this question they stated that other than human interaction this is the top reason species of fish will appear in ponds despite not being connected to any other body of water."
] |
[
"Why do humans need to brush their teeth everyday, but dogs are fine not brushing at all?"
] | [
false
] | I've always wondered | [
"Wild dogs eat a variety of tough foods that need to be bitten/sheared/chewed into pieces. This constant mechanical action keeps their teeth and gums healthy. Pet dogs that get fed commercial foods or food scraps tend to get dental disease alarmingly frequently.",
"It's the same with us. Indigenous people eating ... | [
"Because dogs live so much shorter lives then us. Our teeth evolved hundreds of thousands of years ago when the oldest any human could hope to live would be their late thirties or early forties. \nNow that we have extended our lives by better sanitation and medical care we live much longer then our teeth ever evolv... | [
"good answer, thanks"
] |
[
"How does gravity (gravitons) seemingly affect bodies at great distances instantaneously, yet still adhere to the “nothing travels faster than the speed of light” theory?"
] | [
false
] | null | [
"I'm not sure what makes you say that it seems instantaneous, but it's not. Changes in the gravitational field propagate at c."
] | [
"Well first, virtual particles don't literally exist (see our quantum field theory FAQ for more on that).",
"But let's assume you're a gravitationally-radiating body, like a spinning object with a mass quadrupole moment (spin around, and this will really be true). You are now a very weak emitter of gravitational ... | [
"Well first, virtual particles don't literally exist (see our quantum field theory FAQ for more on that).",
"But let's assume you're a gravitationally-radiating body, like a spinning object with a mass quadrupole moment (spin around, and this will really be true). You are now a very weak emitter of gravitational ... |
[
"What would happen to our planet if a single atom, traveling at lightspeed, made impact with Earth?"
] | [
false
] | null | [
"As others have said, an atom cannot travel at lightspeed. But they can get very close. ",
"In fact, we have detected them hitting earth as fast as 99.99999999999999999999951% the speed of light.",
" Even at this ludicrous speed, atoms are so small that the total energy was not high enough to have a noticeable ... | [
"Depends with what you mean with \"at lightspeed\"\nSince atoms have mass and nothing with mass may ever reach light speed.\nTo do so would require an infinite amount of power.",
"So, if by what ever space magic that was to happen:\nThe end of the Universe as everything collapses into an infinitely heavy black ho... | [
"Well 1) anything with mass cannot travel at the speed of light, and 2) we already accelerate atoms to 99.99999% the speed of light and collide them into each other in super colliders like the LHC. You'll make all kinds of short lived subatomic particles, or break apart a heavier atom. In short, not much will hap... |
[
"Why is it considered healthy to increase your heart rate through exercise, but unhealthy to increase your heart rate other ways? E.g. drugs, stress, energy drinks."
] | [
false
] | null | [
"Human body"
] | [
"Human body"
] | [
"Thanks!"
] |
[
"How many things are going on in a cell at one given time?"
] | [
false
] | null | [
"Lots. Like, crazy lots. ",
"These",
" videos give a pretty good feel for the ",
" of things that are happening in a typical cell, and then multiply that by a couple thousand to get an idea of how complex a single ",
" cell really is (that's a very crude approximation, but for example a typical cell can h... | [
"Keep in mind that scientists by nature are reductionists, we take large problems and try to break them down into very simple, and easier to answer, questions. So, when you see an illustration or animation, you're being shown only the most basic of elements. Some people walk away from them thinking that the cell is... | [
"I was taught this, and thought I understood it but it was only when I visualized some of the visualizations in WEHI that I finally grasped how mind blowingly complex the cell chemistry is",
"http://www.wehi.edu.au/education/wehitv/",
"The one on apoptosis is incredible. "
] |
[
"What is a backdoor in an encyrption algorithm?"
] | [
false
] | [deleted] | [
"It's possible for someone to publish an open source encryption algorithm and/or specification and/or library and for them to claim that it is secure and difficult to break, when really it's not.",
"It may also be possible to engineer this algorithm such that very few people in the world would be able to tell tha... | [
"Usually we're talking about a buried mathematical weakness, where some part of the algorithm hides an exploit that only a few people know about. ",
"A good example is that for a while, people were suspicious of the S-Block stage in the DES cipher. The S-boxes were a set of fixed tables that mapped sequences of ... | [
"Say I create an encryption algorithm that looks like this:",
"P = C + log(exp((K * 1)^1) / 1)\n",
"Where ",
"P",
" is the plaintext number, ",
"C",
" is the encrypted number and ",
"K",
" is the key number.",
"I now tell you that this is the fastest way to decrypt ",
"C",
" using ",
"K",
... |
[
"Were domesticated species chosen because of their innate desirable traits or were they bred to develop those desirable traits?"
] | [
false
] | [deleted] | [
"The initial animals weren't actually chosen for their current purposes. Instead humans would follow herds of these animals. ",
"Over time, humans became more proactive and the animals became dependent on the humans. This was a natural process, pretty much evolution in action.",
"A long time after that, humans ... | [
"Species are breed to enhance interesting traits. ",
"Wildcats",
" (not ",
"feral cats",
") will never be attached to you the way domestic cats can be : you can come to a peace and tolerance treaty, but they'll stay wild. Human selection made domestic cats more friendly and social to humans. ",
"Another f... | [
"Here are the characteristics of ",
"domesticated animals"
] |
[
"What animal is this skeleton part from?"
] | [
false
] | (AskReddit proposed I asked this question here instead) Hey AskScience, My six year old son found this skeleton part that looks like the head of a dragon at the beach in northern Jutland, Denmark. It's roughly 12 centimeters long (4.7 inches). We've been trying to identify what it is, but we can't find anything that lo... | [
"I believe it is the synsacrum and ilium of a bird, though I'm not sure what kind. Basically this is the top of the birds' hip. Most of your pictures are looking down on the synscrum from above. The smoother looking end without any holes would articulate with the rest of the back vertibra, and the side with holes i... | [
"I don't think this is correct. It looks an awful lot like an synsacrum, though I am neither an ornithologist nor an ichthyologist. Why do you think it is the skull of a catfish?"
] | [
"I don't think this is correct. It looks an awful lot like an synsacrum, though I am neither an ornithologist nor an ichthyologist. Why do you think it is the skull of a catfish?"
] |
[
"If an alien civilization sent a probe to fly by earth the same way New Horizon flew by Pluto, could we detect it?"
] | [
false
] | If so, how soon could we detect it? Do we have the technological know how to intercept it? | [
"We could probably detect it. That is of course depending in how big it is. As far as intercepting it, that depends on its speed. If the probe us just doing a fly and not under its own power then its probably going very very fast. Too fast for us to catch up with. In order for our probes to make it out as far as th... | [
"If they were at our same level of technology (ignoring for the moment the whole star travel issue) AND if it happen to fly through an area we were looking at then yes. ",
"On the other hand if they had a functional star drive system and could get here from their home star then they would be way above us in tech... | [
"Cool answer, thank you!\nHow about shooting it (not saying it would be wise, but just to know)?\nAnd how long before could we detect it?"
] |
[
"Do animals generally mate with others near their same age the way humans do?"
] | [
false
] | null | [
"Biologist here! Your question is so broad it's difficult to answer - considering the depth and breadth of the animal kingdom, a simple answer would be yes, no, maybe and I don't know all in one. ",
" mayfly adults, for example, erupt ",
" from bodies of water together, their entire reproductive lifespans lasti... | [
"I wish my biology teachers had been this entertaining. Thanks for the detailed answer!"
] | [
"What an excellent and well-researched answer. You have my respect."
] |
[
"Why do spaceships get cold in space? What absorbs the heat energy?"
] | [
false
] | I have a very limited understanding of the law of conservation of energy from my intro to physics class in a social science degree. My understanding is that for one thing to get cold, heat energy from that thing has to transfer to other matter. Or something like that. So in space, where there is no matter, where does ... | [
"There are three main ways for heat to transfer out of a substance to it's surroundings:",
"Conduction - transfer from particle to particle, which happens mainly in solids, (and best in metals).",
"Convection - which happens by the movement of particles, where a local group particles becomes more energetic, dec... | [
"Why do spaceships get cold in space?",
"They don't. On the contrary, they need complex stuff to avoid overheating. They use stuff like ",
"sun-shields",
" for example. Getting too hot is much more of an issue than getting cold.",
"So in space, where there is no matter, where does the heat go from the space... | [
"Heat can transfer in three ways: convection, conduction, and radiation.",
"Thermos bottles (Dewar Flasks) fight the transfer of heat, either in or out, by addressing each method of heat transfer. First, a lid keeps warm air and steam from rising, slowing the transfer of heat by convection (less-dense, rising vap... |
[
"Every new piece of news regarding the Deepwater Horizon oil spill seems to get worse. My question is this: what's going to happen to the Gulf Coast, and the ocean in general if the spill simply cannot be fixed?"
] | [
false
] | How much ocean life will die? How much coastal life will die? How far would the oil's effects reach? Inquiring minds want to know... and it doesn't seem like I can get a straight answer anywhere, so I've come to reddit for more confusion and insight. | [
"tl;dr: We're fucked."
] | [
"As a resident of America's Wang, I'm worried about the economic impact to Florida if its beaches are ruined."
] | [
"Broad questions get broad answers.",
"A lot of stuff will die."
] |
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