title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Does the diet of an animal really affect the taste of the meat?"
] | [
false
] | This question stems from something often trotted out when people talk about eating roadkill, or seagulls specifically: "They eat nothing but rubbish, they will taste terrible". But does that fact really affect the taste of the meat? I'm assuming the main diet of seagulls (in towns) is "rubbish" like discarded human food. To my un-biology trained mind, surely the processes of digestion would filter out the waste products before they make the meat taste different? P.S: I know killing and eating seagulls is illegal (at least here in the UK). I'm not interested in the legalities, but in the science. | [
"I am not seeing a lot of science here to back up these claims except that people's personal experiences are such that organic tastes better then non-organic, or grass fed better then grain fed. But these are biased opinions. The only way to truely test this idea of better tasting meat is a blind-taste test. Where ... | [
"It can. A diet high in carbs leads to more white fat in meat. This noticeably changes the flavor of the cooked product. "
] | [
"Capercaillie (big grouse-like bird) eats pine needles, flesh tastes like turpentine! Terpenes have robust, aromatic structures. Maybe it simply diffuses through gut? Digestion would not break down terpenes (toxic) only to re-form them in muscle, and yet the birds are inedible."
] |
[
"After hearing the news about the \"habitable\" planet 12 light years away, I'm curious to know how long it would take us to get there given today's technology."
] | [
false
] | I'm referring to this report: If we were to send some kind of probe or satellite or even a lander of some kind, how long would it take us to 1) get something there 2) begin receiving data on that objects findings Obviously it would take 12 years at the speed of light, and we're no where near capable of reaching those speeds (right?). | [
"1) To get something there, it would take a very very very long time. There is a theoretical upper limit on how fast you can get a rocket going from the ground. The reason being this: to get a rocket going faster, you need more fuel. More fuel means more mass. And eventually it just stops being worth it to add more... | [
"It's very hard to say anything definitive about this, but here are some points to consider, partly inspired by all the other discussions going on in Reddit about this.",
"There have been various studies on interstellar ships, see ",
"Project Orion",
" and the later developments section in that page too for m... | [
"You also need to factor in fuel to slow down, effectively halving your potential speed. ",
"To expand on this, there are a few feasible (with great expense) ways we could cross 12 light years in fewer lifetimes.",
"Project Orion being one of them, unfortunately tests were ended in the early 60ties when bans on... |
[
"Does the opposite of the placebo effect work?"
] | [
false
] | I've heard of the "nocebo effect". But for instance, say you take a drug to cure seasickness, you KNOW it is a drug that cures seasickness at 100% success rate, but is it possible that it does not work because you don't believe it will? | [
"Relatively speaking, this would still be the placebo effect. You're believing in an outcome regardless of whether or not its chemically working."
] | [
"Yes, it is possible, but it's still the placebo effect that is at play. "
] | [
"So it is possible?"
] |
[
"Do people with Parkinson's Disease experience mood changes as a result of the loss of dopamine?"
] | [
false
] | I know that senility is an eventual symptom, but I'm more curious about what happens as a direct consequence of the loss of dopamine. I've always been under the impression that dopamine was partially responsible for feelings of pleasure (thus its relation to addiction). Does that mean that people with Parkinson's Disease have reduced feelings of pleasure? | [
"(I've wondered this in the past, but the most recent episode of Curb Your Enthusiasm got me thinking about it again.)"
] | [
"It's not quite as simple as less dopamine = reduced feelings of pleasure, but yes, Parkison's disease is associated with anhedonia (inability to feel pleasure from normally pleasurable activities). Way back in the day I was actually a research assistant on a study looking at anhedonia as a marker of the disease i... | [
"according to ",
"one estimate",
", 56% and 60% of PD patients suffer from depression and apathy, respectively. most estimates of the prevalence of depression in PD fall in the 30-50% range. i'm not sure how much of that is caused by degradation of dopamine pathways vs. other quality of life stuff though.",
... |
[
"My 9yr old asked me why some substances can exist as liquid, solid, or gas - like H2O - and some can't, like wood. Explain for me?"
] | [
false
] | What determines what states a substance can exist in? Is it a simple matter of how complex the compound it? Water is H2O, a cotton shirt or wood table is more complex... I'm making stuff up - help me keep my kid asking good questions. Thanks! | [
"Is it not the case that wood is a composite material, so having \"liquid wood\" wouldn't make much sense because it's a complicated structure that only makes sense as a solid?"
] | [
"Wood does melt! If it is heated without oxygen present it undergoes pyrolysis through which gaseous, liquid and solid products are made.",
"http://en.wikipedia.org/wiki/Pyrolysis",
"A paper discussing molten cellulose, ",
"http://pubs.rsc.org/en/content/articlelanding/2011/ee/c1ee01876k"
] | [
"Well, to put it simply. \"Wood\" is made up of cellulose, which is made up of repeating polymers of glucose (sugar). The glucose is a combination of carbon, hydrogen, and oxygen, which - when heated - will ignite and form ",
" water, carbon (solid), and carbon dioxide. You can then change the forms of carbon acc... |
[
"Is it possible for eyes to change colors? If so, then how is it possible?"
] | [
false
] | Hello ! Everyone always tells me my eyes change colors, but i don't believe them. I always think, how can that be possible? So after hearing it again today i decided to take it to the experts to find out if it's possible. If it is possible, why and when does it happen? Is there a name for this condition? How common is this condition? | [
"Yes it can! Eye colour has to do with the pigmentation (type of pigment and density of pigment) in the stroma of the iris. Some glaucoma medications (prostaglandin analogues) can cause darkening. ",
"Some diseases that affect the sympathetic nervous system inputs to the eye (like Fuchs heterochromic cyclitis, or... | [
"Related question. A girl at my school had one brown eye and one blue. Over 5 years her blue eye started turning brown, starting with a fleck at the top. By the end of school, her eye was brown to the bottom of the pupil but blue under the pupil, with a straight horizontal line. What could cause that?"
] | [
"Not quite. More common with congenital but certainly can occur with acquired",
"http://www.ncbi.nlm.nih.gov/m/pubmed/17878817/"
] |
[
"My google fu has failed me, so r/askscience tell me: what is the current rate of the Suns expansion?"
] | [
false
] | As it fuses hydrogen into helium, the Sun will expand. What are the current estimations for that rate of expansion? | [
"Layman here, I would have thought that because it is in Hydrostatic equilibrium, that it would remain roughly the same size, and not expand at all until it reaches the next stage in its stellar life cycle.",
"Reddit please feel free to correct me if I'm wrong or expand on my answer if I'm correct."
] | [
"I'm not sure where to look it up online (and I'm not with my textbooks right now), so here's how I would think about it.",
"You are correct that the sun expands while still in the main sequence, just quite slowly. This is the same as saying that it moves up and to the right on the HR diagram.",
"The expansion... | [
"The sun is reasonably steady, and isn't currently expanding apart from some oscillation. Not enough H has fused to He to start the expansion yet. "
] |
[
"Is the speed of random mutation to a genome affected by environmental stress?"
] | [
false
] | Do the mechanisms that control mutation operate less effectively during sickness, starvation, etc? | [
"As far as I know the machinery itself (ie DNA polymerases, proofreading enzymes, DNA damage repair pathways, etc) is not affected by environmental stress factors, although oxidative or metabolic stress *within the cell* may influence them in the same way that all proteins will be influenced - if theyre getting oxi... | [
"The ",
"genome shock hypothesis",
" was first really put forth by McClintock and is the idea that hybridization or stress could cause disruptions in the suppression of transposable elements. Transposition is not really mutations, but the general idea is the same.",
"The selective mechanism put forth was that... | [
"Is the speed of random mutation to a genome affected by environmental stress?",
"Yes, evolutionary speaking environmental stressful conditions favor selection (in larger populations) over time as opposed to drift. ",
"Do the mechanisms that control mutation operate less effectively during sickness, starvation,... |
[
"We can see galaxies created shortly after the big bang because their light is only just reaching us now. But something has always bothered me about this."
] | [
false
] | The further away a galaxy is, the longer its light takes to reach us, and consequently the further back in time we can see. Okay, I get this. How far back in time can we see? I've been told almost back to the big bang. Wait, hold on! But WE were at the big bang too! So shortly after the big bang, that same galaxy would have been much much closer to us. In this case, wouldn't it's "young" light have already passed by us? Unless we are each heading in the opposite direction, travelling at close to half the speed of light. Then this makes sense to me. I think. No sure if my rambling is making any sense. Can someone explain this to me? | [
"This isn't actually a problem. The object is fixed in space, it is space ",
" that is expanding. Therefore, the recession speed of the galaxy is only relative to us, not to space itself, and there is no speed of light limit on the expansion of space, as JimboMonkey said."
] | [
"Does this mean, that space expands faster than the speed of light?",
"Space is expanding at a more or less constant rate almost everywhere, so a sufficiently large stretch of space does indeed expand faster than light."
] | [
"I'll just add that you have to take into account the expansion of the universe, which is not limited by the speed of light. There can in fact be galaxies that are \"receding\" from us at faster than light speed."
] |
[
"Can radiation be blocked by means of energy?"
] | [
false
] | ... rather than as typically by matter? Can one make a "lead curtain" that runs off batteries? | [
"Our ",
"Magentosphere",
" is a good example. Although I am not sure it fits your definition of energy.",
"It can stop Alpha particles, which are a type of radiation. But it isn't so good with beta and gamma radiation."
] | [
"That doesn't annihilate the photon, but only alters its probability to be found at certain points in space. The wavefunction for photons describes the same thing as it does for particles, i.e. the probability density and interference just modifies that. ",
"Theoretically, if you want to quench the probability co... | [
"As has been said already, for alpha and beta radiation, this would be possible by electric and/or magnetic fields.",
"For x-rays/gamma rays, i.e. high energy photons, one needs to consider the laws of conservation of energy and momentum. While it is possible to ",
"transfer both with electromagnetic fields",
... |
[
"What makes Swedish iron ore so special?"
] | [
false
] | In both WWI and WWII, the German factories turning out weapons were heavily dependent upon steel produced from Swedish iron ore. In WWI, the supply of this ore via merchant ships in the Baltic was protected by Germany's High Seas Fleet (which otherwise did not have much of a purpose). In WWII, the supply of Swedish iron ore was so critical to Germany's war effort that it was the primary reason Hitler invaded Norway (nothing can be shipped from Sweden to Germany via the frozen Baltic in the winter, so ore travels overland by rail to the coast of Norway and thence to Germany by ship; hence the need to invade Norway to secure the ore supply year-round) and why he had plans in place to invade Sweden if necessary. What exactly are the chemical properties of Swedish iron ore that made it so desirable for steel production? Why was Germany unable to produce sufficient steel for its war effort using only the iron ores available in the areas of Continental Europe under German control? What was "wrong" chemically with those ores as far as steel production was concerned? I'm not sure this is exactly a "science" question, more about geology/manufacturing processes etc. | [
"Swedish iron ore is very pure (specifically low sulphur content). Before the modern ",
"Linz-Donawitz-steelmaking",
" process, sulphur impurities were very costly to remove.",
"However the main reason Germany desired Swedish steel was not for its quality but its quantity. 40% of Germanys prewar iron ore supp... | [
"Party it has to do with the purity of the ore. For some reason the iron content of the ore in Sweden was higher than anywhere else in Europe. Part of its reputation comes from the fact that the king of Sweden brought in experts from around Europe to work the ore & the exchange of knowledge resulted in hire qualit... | [
"The demand for iron ore in mainland Europe started in the iron ages, and for thousands of years, all of the ore came from mainland Europe. Hence, there simply wasn't enough left to be used on such a large scale ",
".",
"Northern Sweden ",
" has never been densely populated, hence has never had much reason to... |
[
"Why are we left-handed or right-handed?"
] | [
false
] | null | [
"This question",
" was asked earlier today."
] | [
"That didn't answer my question. That link was about personality types."
] | [
"Yes, yes it was. I fail at multitasking for the day. ",
" question",
" was asked earlier today. Thank you for pointing out my mistake."
] |
[
"When I add CO2 to water, why does it taste different? Am I tasting the CO2 or is it enhancing some of the flavors that are already present?"
] | [
false
] | null | [
"The carbon dioxide dissolves to form carbonic acid and bicarbonate ions, so yes you're tasting the CO2. "
] | [
"Just to elaborate a little bit- Sourness is a taste affiliated with acidity, meaning the carbonic acid is detected by the same cells responsible for tasting other acids in any foods (e.g. citric acid in oranges or tartaric acid in wine)"
] | [
"To unnecessarily add on, the addition of CO2, by lowering the pH, also affects the speciaition of tons of other species in solution, so you could be tasting compounds that existed at a very low concentration at your starting pH and become exponentially more concentrated as the pH changed. This included affecting t... |
[
"A question about Coulomb Force and its equivalence in real life ?"
] | [
false
] | So i was solving a question " Two 1 Coulomb charges are placed 1 km apart the force on them will be " Answer was 9000 Newton . Now when we life weight of ground suppose 100 kg it takes Mg newton that is 980 Newtons . My question is why we cannot see that 9000 Newtons force around us and why it doesnt affects us plus i am sure there are hell lot of charges around 1 km distance | [
"Because everything is pretty close to neutral in charge.",
"The Coulomb force causes positive and negative charges to attract each other, to form atoms etc. Two neutral atoms don't attract each other very much. Their protons push away from each other, their electrons push away from each other, but their protons ... | [
"A neat question I've read that puts this whole neutrality thing into perspective is, \"What would happen if you lost 1% of your electrons?\" That seems like a fairly small imbalance away from neutral... but the Coulomb force is so strong that even that 1% imbalance in electric charge would contain so much energy t... | [
"Generally, you can only have very weak net charges, because the Coulomb force is so strong that any strong charge will cause electrons to fly away or get drawn in, and the charge will become mostly neutralised",
"An everyday example of where you see this in action is when you get a static shock when you walk acr... |
[
"If mass matters in the solar system with relation to gravity (Jupiter vs Mercury for example), why doesn't that apply to mass of smaller objects (a feather and a bowling ball). Why do those two fall at the same rate?"
] | [
false
] | null | [
"For some people equations work best to explain something, so let's give this a try.",
"Force of Gravity (F) = G*m1 *m2/ r",
"Say m1 is the earth and m2 is the bowling ball or feather. And they are both the same r from the center of the earth.",
"Now the rate they fall is determined by the acceleration with t... | [
"Yes I think OP is asking why the feather and the bowling ball fall at the same rate if their specific gravity is the different.",
"The answer is, they aren't ",
" the same. Over a long enough distance of fall, with no air resistance, you would see an infinitessimally small difference, about the same as the pe... | [
"Point was if m2 was large enough then m1 would move towards m2 while m2 moves towards it. If your reference point was on m1 then m2's rate of \"fall\" would be higher than what the equation above shows."
] |
[
"Is there a good way to simulate a fiber optic internet connection between two computers?"
] | [
false
] | null | [
"Huh? To what end? What are you trying to determine?"
] | [
"I was wondering how much if a difference I would notice using a fiber optic internet connection, which can supposedly send a gigabit per second, as opposed to copper cables like we have in most of the USA, which usually get something more like 10 megabits per second.",
"I don't know of anywhere near me that has ... | [
"You will not see any qualitative distances at such a short distance. ",
"Twisted pair actually can support over 100 Mbps at under 100 feet (see fig 3, PDF)",
". Fiber optics sets itself apart in how little the data rate drops off over distance. This is not something you can test with two computers.",
"Furthe... |
[
"Sorry, another question regarding the speed of light. And no, it's not about FTL."
] | [
false
] | The way I understand it, we know that the speed of light is the maximum speed allowable in the universe because light will always go the maximum spacelike velocity allowable in the universe. Or, all of its 4-velocity is in the spacelike dimensions. None in timelike. We know this because when we examine light mathematically we find that it will simply travel at the maximum allowable velocity, no matter what. So we measure the speed of light and say, "OK, that's the max." Light doesn't set the limit, something else does and because of the nautre of light, light is uniquely situated to show us what that limit is. This completely blew my mind when I first got it. Hell, just the ideas involved in getting to that conecpt blew my mind. The following is based on that overly simplistic understanding. So if the above is wrong, please correct me. What is the something? Do we know? If so, what is it? If not, what are the most reasonable ideas? | [
"You are right that the speed of light, the \"universal speed limit,\" is not set by light. Moreover, I think you are really on the right track towards understanding this fundamental idea in physics, which is always really nice to see in this board. In General Relativity, gravitational radiation also propagates a... | [
"Nothing \"sets the limit.\" You're — due respect — way overthinking it.",
"How many inches in a foot? Twelve, right? So we can define a constant, call it ",
" and say that ",
" = 12 inches/foot.",
"Now, ",
" is this true? What \"sets\" the value of ",
" The answer is the ",
" sets the value of ",
"... | [
"distances and times are essentially the same thing",
"woah"
] |
[
"Why isn't combination therapy long term?"
] | [
false
] | Combination therapy (using numerous therapies/drugs to treat a disease) is used I believe when treating bacterial infections to prevent development of drug resistance. It's basically used because the chance that a colony of bacteria is resistant to a number of antibiotics simultaneously is very unlikely. And so my question is; why isn't combination therapy the answer to antibiotic resistance? (sorry if it seems like a silly question! Thanks to all responses in advance :) ) | [
"Combination therapy will increase the number of generations needed to achieve resistance, but it will not increase it to infinity. Pathogenic bacteria will still slowly evolve resistance to the antibiotics, but it gives us more time to come up with novel treatments. "
] | [
"Sequential administration of antibiotics (try A, when A stops working switch to B, and so forth) is pretty much rigging the game for bacteria (and I should note that pathogen resistance is found in almost every class of pathogenic organism: virus, bacteria, protist, fungus, etc.). Combination therapy helps, but i... | [
"Also, keep in mind expense and side-effects. Using multiple drugs at one time means paying more and exposing your patients to more drugs than possibly needed. I don't know if I've ever seen someone prescribed combination therapy for the purpose of treating one bacteria with good susceptibility to a given antibioti... |
[
"How does fat \"burn\" when we exercise? Where does it go?"
] | [
false
] | [deleted] | [
"You forgot acetone, acetoacetic acid, beta hydroxybutyric acid. Ketones, which is why fat metabolism is ketogenic.",
"Glycerol is an interesting resulting byproduct, well not interesting that it is there but what becomes of it. With amino acids pyruvate and lactate, these will form into glucose. It is a homeos... | [
"You forgot acetone, acetoacetic acid, beta hydroxybutyric acid. Ketones, which is why fat metabolism is ketogenic.",
"Glycerol is an interesting resulting byproduct, well not interesting that it is there but what becomes of it. With amino acids pyruvate and lactate, these will form into glucose. It is a homeos... | [
"Ketogenisis is not the only form of fat metabolism, or even the preferred form. In general fatty acids undergo beta oxidation to form acetyl-coa which then is processed by the krebs cycle, producing CO2. Whether the acetyl-coa is made from glucose as a consequence of glycolysis or from fatty acids the krebs c... |
[
"If energy were no object, what are some scaleable ways to pull CO2 out of the air and bind it to some solid?"
] | [
false
] | [deleted] | [
"At this point it is more a question of efficiency than low energy approaches. As per your example, let's say I have 500MW of nuclear electricity. What is a better use of that energy - to pull out 1 unit of CO2 from the air or to displace 3 units by shutting down a coal power plant if comparable production?",
"At... | [
"You can actually convert it directly to carbon if energy is no object. I did some reasearch on this when I was bored and I wanted to design some form of CO2 -> C + O2 device and I thought I would share. ",
"So the first step is getting pure CO2 since the concentration in the air is actually quite low. The method... | [
"I'm sure there are people here more knowledgeable than I am on this particular issue, but what you're looking for is called ",
"carbon sequestration",
" or ",
"carbon capture and storage",
".",
"The simplest of these are using biological systems, like trees or algae, that naturally use photosynthesis to ... |
[
"Does science believe that animals have names for each other like humans do?"
] | [
false
] | I'm sorry, I don't know a more intellectual way of wording this. | [
"Yes. Dolphins have a signature whistle, which accounts for over half of all the whistles they produce, and is unique to each individual, kind of like signing off every comment with your username. In a recent study ",
"published in Proceedings of the Royal Society",
", King et. all found that ",
" dolphins wi... | [
"This is amazing! If they have advanced communication like this how have we not managed to communicate with them in a 2 way conversation yet? "
] | [
"Really the important word there is \"",
"\". ",
"It seems like they have a complex language with structure and syntax. But we've never been able to understand it if it's there. ",
"The really cool earlier work on the dolphin names though found that the calf's names are a variation of their mother's names... |
[
"How do we know that all the physics constants are constant in the whole universe?"
] | [
false
] | [deleted] | [
"We don't know ",
". But every observation we can make in our observable universe has pointed to them being the same within our observable universe. So we have to take a piece from the philosophy of science and invoke the principle of parsimony. If we were to ",
" that they vary with location in space, then tha... | [
"This is actually a very compelling question even though it can sound silly before you start to think about it.",
"It seems like others have pretty satisfactorily answered your question so I won't clutter this up but I did want to provide a link to a wiki article relating to this about the cosmological principle.... | [
"yes, there have been hypothesized versions of that. metastable vacuum states (ie, it collapsed once, but only so far, and could collapse again) are an example. There are hypothesized cases where the collapse happened subtly differently in different regions of the universe... interesting ideas, but not scientific u... |
[
"What causes smoke from combustion?"
] | [
false
] | Admittedly, as a high school sophomore (year 10), my knowledge is rather limited, but why does smoke form from a fire when the generic formula for combustion is Hydrocarbon + oxygen -> CO2 +water ? | [
"So is ash a result of incomplete combustion?"
] | [
"Smoke can be made up of many compounds. The amount and type depends on how much oxygen is available to the fire, the temperature of the fire and what is being burned. Except in carefully controlled circumstances, anything you burn will have impurities and won't burn evenly.",
"Smoke from a well oxygenated wood f... | [
"Yes, exactly. From ",
"wikipedia on combustion:",
"Complete combustion is almost impossible to achieve. In reality, as actual combustion reactions come to equilibrium, a wide variety of major and minor species will be present such as carbon monoxide and pure carbon (soot or ash). Additionally, any combustion i... |
[
"Are we among the earliest generations of intelligent life in our galaxy?"
] | [
false
] | Please feel free to rip apart this back-of-a-napkin estimate: Given these numbers, the odds are not too bad for life in our galaxy, but not necessarily for intelligent life at this point in time. | [
"While no one has an answer to your question, you may find it interesting to review ",
"the Drake equation",
". Since we have no method for surveying other solar systems for life (yet), all we can do is consider the factors that go into it. The Drake equation summarizes those and leaves the unknowns as variable... | [
"You're not the first person to consider this possibility."
] | [
"also, keep in mind, intelligence isn't the \"goal\" of evolution. It's worked well for our species, but plenty of others have come and gone and done very well for themselves without it. It could be that the selection pressure to generate intelligent life is very low generally, or that intelligent life exists very ... |
[
"What does nuclear waste actually look like?"
] | [
false
] | Google images says it looks like a yellow barrel. I wanna know what's inside! | [
"It depends on the type of waste.",
"If you are referring to \"Nuclear Waste\" as \"Spent Fuel\", the stuff we take out of reactors, then it looks exactly like the fuel we put ",
"INTO the reactors",
", ",
"except it glows when it is under water.",
". Inside the rod, originally you start with ",
"uraniu... | [
"Piles and piles of these:",
"http://upload.wikimedia.org/wikipedia/commons/2/28/Fuel_Pellet.jpg"
] | [
"Pretty boring. Can look like metal, powder, liquid, chemicals. Nuclear waste just means that a Geiger counter scan shows counts per minute that is high enough to classify it as waste.",
"Here's some fuel rod and liquid rad waste which has been undisturbed for several decades.",
"https://en.wikipedia.org/wiki... |
[
"What is actually happening when you get dizzy from say spinning in a chair? Is there a quick way to nullify these effects?"
] | [
false
] | [deleted] | [
"Would spinning backwards stop the effect?"
] | [
"Would spinning backwards stop the effect?"
] | [
"Shake your head (like you are saying no) vigorously, to lessen sensation of dizziness. "
] |
[
"Is it possible for planets to safely orbit a black hole as if it were a star? Why dont't the stars at the centers of galaxies get pulled into the black hole?"
] | [
false
] | null | [
"Is it possible for planets to safely orbit a black hole as if it were a star?",
"Yes. Gravitational pull is determined by mass and distance. Black holes act like any other massive body with respect to gravitation (so long as you stay outside the Schwartzchild radius).",
"The idea that black holes \"suck thin... | [
"I think what you mean is that no one is teaching the layman about black holes except for Hollywood, and Hollywood black holes are giant space vacuums."
] | [
"Building on AnteChronos' answer, perhaps an example would help.",
"Say you are standing on the surface of the earth and you weigh 100 pounds. The gravity of the earth pulls on you with a force of 100 pounds.",
"Now imagine the earth were squeezed down to the size of your thumb. All that mass concentrated in a ... |
[
"What is the physical structure of a brain?"
] | [
false
] | null | [
"It is not liquid. You can go to a butcher and buy a brain. It is solid."
] | [
"I did clearly know it wasn't a liquid (I don't like my physics teacher) but they were arguing that because it's squishy/mushy it fills the shape of its container."
] | [
"Squeeze a sponge and hold it in your hand. It molds to your hand. It is not liquid."
] |
[
"How do caterpillars become butterflies?"
] | [
false
] | I've always been taught the basics, caterpillars eat a lot, weave a cocoon, stay there for some time and come out with a new body and wings. But what exactly happens in the cocoon? What is the body breaking down into - amino acids/individual cells/ different tissues - and then rebuilding / reconnecting? And what guides the rebuilding? If they've broken down into primordial goop, is there's still a brain directing the reformation? | [
"They don’t completely liquify in the cocoon, that’s an urban myth. When a caterpillar goes into the cocoon, parts of its old body start to break down, but certain essential groups of cells don’t. They’re the starting point for most of the major features, like eyes or wings. ",
"Some caterpillars actually have un... | [
"Ohhhh okay so it's a little like Caterpillar puberty then? The parts were there but didn't kick in until a certain age/ time. The parts that break down- are your parts composed of stem cells or something like that? So they have the capability to reform into wings/a new body?"
] | [
"I study insect development so maybe I can help you out. Think of the pupa as just another stage on the way from egg to larva to adult. Metamorphosis is completed in the pupa but is a much more gradual process than you might think! Things are already happening well before the pupa forms. Also FYI most of my knowled... |
[
"If you fill a torus completely with water and begin rotating the torus, does the water inside begin rotating as fast as its container, or is there always some amout of friction between the interior of the torus and the water it contains?"
] | [
false
] | I'm wondering whether a salt water filled graphene torus could be rotated to generate electricity. As a follow up: If you nest a static torus inside the rotating torus, anchoring it with magnets, would that allow for energy to be generated? | [
"The water would eventually spin as fast as the toroid because the walls of the toroid would \"pull\" on the water with friction. The water would never be able to go faster than the toroid if the toroid is accelerating or keeping it's rate of spin. This could be used for energy storage as a flywheel but would be e... | [
"No, why would the water start rotating as fast as the container? It will speed up to the speed of the torus due to friction.",
"The follow up - is it a smaller torus. Like, one inside the hole of the torus, or one within. Actually, I don't think it matters. Why on earth would this generate energy? I mean, it... | [
"True, I was reading this article at work",
", and it seems you are right, but of course, I'm trying to come up with something that utilizes the properties that graphene has recently been shown to display. So, instead of water, what if I used a Paramagnetic Ionic Liquid and nested another torus inside the larger ... |
[
"With evidence growing of autoantibodies in patients with persistent Long-COVID-19 symptoms, what is the outlook for this large population of survivors?"
] | [
false
] | null | [
"Questions based on discussion, speculation, or opinion are better suited for ",
"r/asksciencediscussion",
"."
] | [
"I'm asking about existing knowledge around autoantibodies and how they affect chronic disease - it's a large topic and not speculative"
] | [
"There’s no information about the scenario in COVID, so any answer must be speculative. If you can broaden the question to cover well documented scenarios that can be answered from published literature the question could be approved."
] |
[
"How is fructose imported into the cell?"
] | [
false
] | I recently learned that diabetics can eat fructose fruits. After I thought about it this was unsurprising considering there is no reason to think fructose is imported via the prototypical insulin pathway that imports glucose. But this made me wonder how fructose actually is imported into the cell. I looked around and found out that GLUT5 is the main transport protein in the process, but I could not find much about it in the literature. Any help would be appreciated, Thank you! | [
"GLUT5 transports fructose into the body through facilitated diffusion. For instance, in the small intestine, the epithelial cells contain GLUT5 on their apical sides (Facing into the lumen of the intestines). This transporter moves fructose via facilitated diffusion. So, the concentration is higher in the lumen of... | [
"There is no active transport of fructose whatsoever? Wouldn't this lead to fructose in the urine, and wouldn't it be terribly inefficient?"
] | [
"I'm not sure of the specifics of the nephron and the kidney, I just remember GLUT5 participates in facilitated diffusion of fructose in the gut epithelia",
"I can assume that the nephron also participates in FD to reabsorb fructose in the proximal convoluted tubule.",
"I'm not saying this is universal, I'm jus... |
[
"Are black holes disc shaped or actually spherical?"
] | [
false
] | Because black holes are usually represented as a disc on a single plane, I wondered what I would see if I were able to orbit one on its equatorial axis. Are black holes actually spherical but represented artistically as a disc? Thanks! EDIT: I'm grateful to all who answered. An additional thought: Because a black hole is spherical, objects can enter from any direction, are the rays emmitted dispersed in all directions like the Sun? I ask because again, artistically it is always represented as a jet from the center. EDIT: Are their exaples of a black hole with bodies orbiting it with different planes? I realize that most Galaxies, Solar systems, etc. tend to lie on a single plane. | [
"A non-rotating black hole will be perfectly spherical, if it rotates, it will bulge out in the middle like the planets do. "
] | [
"This is correct and should be the top answer. Furthermore, all non-primordial black holes should have angular momentum and therefore an event horizon which is an oblate spheroid (bulging at the equator). Since primordial black holes have never been observed, ",
"."
] | [
"However, even quickly rotating black holes are still only a few centimeters bulgier at the equator than pole to pole."
] |
[
"If a simple robot is designed to move towards the sun at a given rate, what path will it trace during the day?"
] | [
false
] | [deleted] | [
"Springtime on the equator: Robot goes in one direction, stops, robot goes in the other direction ends up where he started. --> Line",
"Springtime Europe: Robot starts out going east and slowly shifts his direction until he ends up going South and finally goes west. Draws a pretty good half circle.",
"Summer i... | [
"Here",
" is a screen shot of a quick LabView program I made. It uses an existing subvi that calculates the sun's location (altitude and azimuth). ",
"Here",
" is a reference website I used to make sure the sun path data was correct. The path graph starts at point (0,0) and uses the azimuth angle to calcul... | [
"Polar regions in the summer: Robot will travel in 24-hour circles, all summer long. "
] |
[
"If placed in a controlled environment, do trees that normally undergo seasonal leaf Abcission stop losing their leaves?"
] | [
false
] | [deleted] | [
"I'm not any kind of expert, but no one else has answered this; so I looked it up, and I'll try my best.",
"From what I'm reading, deciduous abscission results from a decrease in production of auxin in the leaves. This triggers a physical change in a dual layer of cells connecting the leaf to the tree, called (ap... | [
"There is also a decrease in photosynthetic efficiency in foliage as it ages, which would cause problems in the long term if the light environment were held constant. This is the reason that evergreen trees, which hold their foliage for multiple growing seasons, also shed old foliage. For instance, eastern white ... | [
"There was a photo posted here a couple years ago that had a row of trees that were in various stages of turning color, because they stood in front of a building that blocked the evening sun at different times to the trees. Basically created an artificial difference in the amount of sun each tree got as you went do... |
[
"When have coral reef been wiped out and come back?"
] | [
false
] | [deleted] | [
"Importantly (and correctly) the previous poster indicated that 'reefs', not specifying a particular organism that built the reefs, have come and gone. Large reef complexes, as structures, have existed at a variety of times during Earth history, but the organisms that built them at these different times have not al... | [
"Is the current alarm over the ecosystems (like the decline of the Great Barrier reef) warranted considering reef ecosystems seem to be cyclic?",
"Considering it would take millions of years to come back? Depends if you value biodiversity"
] | [
"Is the current alarm over the ecosystems (like the decline of the Great Barrier reef) warranted considering reef ecosystems seem to be cyclic?",
"Considering it would take millions of years to come back? Depends if you value biodiversity"
] |
[
"[Physics] I have some questions abour light. How can polarizatiom, bifrigence, and transmission be explained considering the quantum nature of light?"
] | [
false
] | What I don't understand about polarization is how quanta of light can become elliptically polarized. My understanding is that each photon has a pair of perpendicular, transverse electro and magnetic waves [why is there the electromagnetic component? How does it interact with matter?] how does this photon become elliptically polarized? I'm reading (the wiki article on polarization)[ ] and, in the polarization state section, I'm confused about when they discuss how shifting a component of the electromagnetic wave introduces a circular polarization. Is this talking about adding photons together? I've also heard about polarizing light and then splitting it into perpendicular polarizations- how is this possible? If all the light is in one orientation and wavelength, wouldn't this split photons in two? I've done experiments where light can be polarized to a certain amount by passing through a certain length of material, and changing the length changes the orientation of polarization. How can a homogenous material 'spin' the orientation by a certain angle depending on the time light spends in it? I've also heard lay explanations of how light is coherently transmitted (as in glass) but I still don't understand. I know that light interacts with the electrons in a certain way as to slow it down- how can all of the light interact with electrons and yet all maintain coherence? Are they being absorbed and instantaneously retransmitted, or is there a different interaction? How does the electronic structure of a material exactly change how light interacts with it? Finally, I have a bonus question about snell's law, or the principle of least time. I see this explained as how light will find the shortest path between two points in materials of different refractive indices, always illustrated by thus graphic . I don't get what this graphic trys to display- light can take any path and be refracted at any angle from the starting point- this looks as if light only takes one path from the starting point, through the material. Can somebody clarify this for me? | [
"Perhaps a lot will be clearer if you get the ",
" nature of the measurement of light's polarization. Classically, light is a transverse electromagnetic wave. When one measures a photon's polarization it assumes a definite value, i.e. some orientation. To say that light is ",
" means that all electric field dir... | [
"I can't explain the polarization of single photons, but I can try to help with the electromagnetic explanations.",
"As you said, light changes velocity when it enters a material such as glass. If all the light (from a coherent source) spends the same amount of time in the lower velocity medium, all the waves wil... | [
"how does this photon become elliptically polarized?",
" ",
"Is this talking about adding photons together? I've also heard about polarizing light and then splitting it into perpendicular polarizations- how is this possible? If all the light is in one orientation and wavelength, wouldn't this split photons in t... |
[
"What's a viable energy source you know about that most people aren't aware of?"
] | [
false
] | It seems we've all heard something about solar, wind, nuclear, biofuels, algae, petroleum, geothermal, and hydrogen. Do you know any other energy-dense materials/processes (e.g. , lightning, non-negligible forms of human power) that might have promise - if not now, then perhaps in the next few decades? | [
"Thorium nuclear power, and molten salt reactors in general. The current generation of nuclear power is dead, but most people know nothing about the next generation."
] | [
"You know what I know about that most people aren't aware of? The fact that we cannot harness \"zero-point energy\" for anything, or at least, anything useful. And that all the people claiming to do so either want lots of attention or lots of your money.",
"So... beware of those guys. Seriously. "
] | [
"no, by its definition it's not useful. Think about it, how can you extract energy from something that is defined to be in its lowest energy state. I know people like to think the way you do, but there ",
" impossible things in the universe, and we've learned a lot about them over time."
] |
[
"Light is usually presented as traveling, ie the speed of light or how it is propelled out of a flashlight. What is the force that moves light?"
] | [
false
] | Basically I want to know what causes light to travel in the first place. Is it just inherently in motion, or is there an external force that causes it to move? | [
"Yes, momentum is a fundamental property of photons (like all particles). The momentum of a photon is h/λ where h is Planck's constant and λ is the wavelength of the photon. ",
"A force is actually something that ",
" momentum, so no force is needed for something to keep going with the same momentum."
] | [
"Also, keep in mind that unlike a gun, in which a bullet has mass, and thus inertia, and began at rest, the photons coming out of your flashlight have no mass, and therefore always travel at the speed of light. The \"push\" comes from the electricity that excites the filament causing the electrons to jump energy st... | [
"Thanks to both of you. After posting I got to thinking that it was something fundamental regarding photons but this clears up the fog for me "
] |
[
"Do viruses become resistant to natural human antibodies similar to antibiotics? If so, wouldn't bacteria eventually become superbugs no matter if we use antibiotics or not?"
] | [
false
] | Also if we someday manage to build micro/nano robots that can destroy bacteria using laser or something similar, could bacteria evolve and become resistant to that as well? | [
"Quick point first, you seem to be conflating bacteria and viruses. Those are ",
" different things. You have more in common with a tree than a bacteria does with a virus. Antibodies and antibiotics are also very very different, and don't really have anything in common beyond a similar name.",
"But to answer th... | [
"\" First, our antibodies are more or less randomly generated, and unique to each person (I can go into more detail here if you want).\"",
"Please do.",
"\"So if some virus was \"resistant\" to the antibodies of one person, that wouldn't necessarily help it against anyone else.\"",
"If this was the case then ... | [
"Yikes, got called on it. Better find me some textbooks :)",
"It seems I spoke too rashly before. Your question on IV immunoglobulin resistant pathogens is rather puzzling, I dont have a good answer. ",
"Antibodies are proteins that are more or less \"Y-shaped\". The stem is one of a few different types, and de... |
[
"Do cats or dogs ever kill large birds of prey?"
] | [
false
] | I know the opposite happens, but I can't find any incidents of pets killing large birds iof prey. Is this known to happen? Are there any predators that are likely to go after predatory birds? | [
"All large birds of prey are vulnerable to predators when they are on the ground, but there aren't any animals that actively hunt them. As eggs and nestlings, they are very vulnerable if a parent is not on the nest."
] | [
"The fact that birds of prey can fly away and make very fast escapes means that anomalies like the ones you're thinking about are very rare because of the way that the two don't really cross paths as often as the others do, for example if a bird of prey ever lands on the ground it isn't for very long, And dogs and ... | [
"Yes I'm aware of that, but I'm interested in these types of anomalies, and recorded instances of such. For example, jaguars have been seen killing and eating crocodiles, wildebeest killing lions, falcons mobbed and killed by gulls etc. Certain breeds of dogs were originally bred to be able to protect cattle agains... |
[
"Are there any significant instinctual behaviors in humans, aside maybe from language? Like; moles dig, birds build nests, bears den & hibernate, etc."
] | [
false
] | So many animals have instinctual behaviors that are universal to their species, but don't seem learned or passed down. Like bird species that build particular shape nests, beavers make dams, or animals that burrow or migrate, etc. And the animals obviously have no idea why they do those things. Is there an equivalent in humans? The only thing that come to mind really is language; our brains seem built for it and crave communication. But it's not like we are driven to build nests without knowing why. Maybe some parenting instincts, or fear of the unknown perhaps? Not sure if I have sufficiently stated the intent of my question, but thanks for considering it. | [
"Sucking on a nipple."
] | [
"fucking"
] | [
"Humans instinctively build themselves into social hierarchies. When you look at it, most of human interaction is based on either figuring out where you stand or in increasing your stature. ",
"We also instinctively categorize things. This is more a function of our cognitive processing, but it happens. ",
"We i... |
[
"If the earth isn't a complete sphere, are their certain points on earth where gravity is actually pulling at a slight angle and not directly down?"
] | [
false
] | null | [
"Don't we usually define \"straight down\" to be the direction in which gravity points? "
] | [
"One of the motivators of the ",
"Cavendish experiment",
" was the survey of the Mason-Dixon line. The surveyors found a small systematic error that they couldn't quite eliminate. As it turned out, their plumb-bobs weren't quite pointing perpendicular to the reference ellipsoid because of the existence of the A... | [
"By \"straight down\", I believe he means perpendicular to the surface of the Earth."
] |
[
"Why is North America and Europe largely void of native marsupials like sweet Platypuae or awesome koalas/kangaroo?"
] | [
false
] | I know there are a few marsupials native to NA and Europe, and I've heard of some kangaroos in some French forest, but why are all the sweet animals in Australia? | [
"Basically it has to do with continental drift and the isolation of Australia (and South America). South America eventually became connected to North America which resulted in placental mammals migrating and taking over niches there. Australia is still isolated and therefore the marsupials have been relatively left... | [
"I sort of asked the opposite question a while ago here: ",
"http://www.reddit.com/r/askscience/comments/jvtiz/why_were_rabbits_so_invasive_in_australia/"
] | [
"Came here to show the same link from Berkeley! Its pretty crazy how it managed to isolate one type of animal.\nAlso if you want to learn about a really cool marsupial is Australia check out the honey possum.",
"http://en.wikipedia.org/wiki/Honey_possum"
] |
[
"Is the DNA in one cell the same as the DNA in all of my other cells?"
] | [
false
] | [deleted] | [
"Central dogma is that yes. Every cell in your body (with the exception of your sex cells, as they are haploid containing a random 50% of your DNA) carries the same DNA. This is your \"germ line\". At the high school or even undergraduate level, this is probably the extent of what will be covered.",
"By and large... | [
"It has long been thought that the DNA is the same, albeit with epigenetic variations that allow for differential expression of parts of the DNA. But recent evidence is beginning to show that different cells can have different DNA.",
"This",
" study looked at a specific gene, BAK1, in relation to a specific hea... | [
"Generally it's the same DNA in each of your cells, directly copied with each cell division since you were a single cell. There's a few exceptions, where a cell may not have exactly the same DNA as the rest:"
] |
[
"Can you cool yourself quicker by breathing cold air vs drinking cold water?"
] | [
false
] | [deleted] | [
"I am reposting this as a top level comment as it seems to address your question more directly than as a simple retort to others.",
"First take the tidal lung volume as 0.5L. According to wolfram alpha the mass of a half liter of air is 0.64 grams and obviously the mass of a half liter of water is 500 grams. So t... | [
"for me, if I see 4 vs seeing 1 in a back of the envelope calculation...I'd call them both 1. Pi is approximately 1 in back of the envelope calcs if you're looking at orders of magnitude. I'm not going to be discussing order of mag calculations anymore in this thread, it's digressed off topic and really doesn't m... | [
"I don't understand what you mean by cool yourself.",
"Are we talking about your internal temperature(as in a fever) or are we talking about the fact that you feel markedly warm from exercise or the like?",
"I'm not even sure I can properly answer this for you, but I can prevent some of the false information th... |
[
"Has VY Canis Majoris become a BlackHole \"in earth time\"? Would this be the closest BlackHole to earth?"
] | [
false
] | null | [
"Has VY Canis Majoris become a BlackHole \"in earth time\"?",
"Doubtful. It's only 4000 lys away, which is still a short amount of time for stellar evolution even for massive stars. ",
"Would this be the closest BlackHole to earth?",
"No. A0620-00 is closer to Earth"
] | [
"a. Theres no evidence of it. So the best bet is 'no'. Theres little point in trying to guess the state of things that are effectively completely out of ability to determine. From our personal frame of reference it hasnt happened yet. Its still to occur in the future.",
"Not sure about the distance..."
] | [
"We can't tell and the answer is probably no.",
"However, one more point that is related: When two events occur close enough in time that light hasn't had time to get from one to the other, relativity doesn't allow you to order them.",
"So for instance, New Horizons is about 5 light hours from Earth now, and I'... |
[
"If you get electronics wet, after the water evaporates, why doesn't the electronics return to normal?"
] | [
false
] | Does water blow up electronic circuits or something? I don't seem to understand how by simply for water and electronic devices to make contact it will affect the little metal pieces that intertwine. | [
"It's not the water itself, distilled water isn't a good conductor. But tap water or rain water consists of enough salts to conduct electricty up to the level damaging it.",
"That said, getting electronics damaged happens mostly due to shortcuts in powered electronics. If there is no power source peresent, most e... | [
"Often, there are minerals in the fluid that do not evaporate. These can often cause electrical components to short or damage them in another way. Fluids are especially good at delivering their solvents into hard to reach places, and those places on, say, a circuit board, are not always happy when there are foreign... | [
"Does this mean that some problems can be remedied by rinsing with DI/distilled water?"
] |
[
"Solving world hunger with enzymes? Why not?"
] | [
false
] | We have pills which give us enzymes, such as lactase, which allow us to digest certain sugars, such as lactose in dairy. Why then is it that we cannot make a pill for cellulase, enabling people to digest the cellulose in plants and possible solving world hunger? Does it have anything to do with the fact that it is never found naturally in the human body? | [
"Because world hunger is not a food problem. ",
"It's a problem of delivery. Most of starving people and people who don't get enough nutrients, live in unreachable areas. Those areas can be unreachable due to natural caused (common in SE Asia, due to rainy season, etc.) or due to man-made problems (wars, other co... | [
"Animals that digest cellulose aren't relying on just one enzyme.",
"They have very complex bacterial cultures, often distributed over a much longer intestinal tract, to pull off this feat.",
"Even so, many of them do a mediocre job: cows, for example, produce mass amounts of methane (which means untapped energ... | [
"The point he is trying to make:",
"Because world hunger is not a food problem.\nIt's a problem of delivery.",
"What you just said:",
"world hunger would be solved. We would not need any mass transportation of food.",
"So you both agree the problem is delivery. Where is he wrong?"
] |
[
"What causes the noise from speakers when you touch a speaker cable?"
] | [
false
] | Just using the end of an aux cable here | [
"Mainly how sweaty your skin is, and how tightly you grip (to a point). "
] | [
"Do you mean that you have an Aux cable plugged into the amp, and when you touch the free end you get noise? ",
"Your body has various properties that are electrical (but have nothing to do with the electrical nerve impulses). You are a conductor of electricity, but a very poor one. Your body has capacitance (t... | [
"Oh ok, I get it, thanks :) What sort of factors affect our conductance? Because having another person touch the cord provided a deeper sound. "
] |
[
"Why do rubber bands deteriorate the way they do?"
] | [
false
] | I'm sure you've encountered decades-old rubber bands that have become crusty and friable. I came across one that was almost completely "caked" onto an old set of engineering plans. So, what's behind this transformation? | [
"Strain crystallization",
" would be be primary guess. Rubber remains, well, rubbery because the polymer chains are unable to align. By applying stress, the polymer chains are able to crystallize over time making the rubber brittle.",
"Rubber bands are made from natural rubber which is primarily poly-isoprene. ... | [
"My guess (not an organic chemist) is oxidative damage. Rubber is just a polymer of organic compounds in such a structure to make it stretchy, but many organic molecules will degrade from oxidation as bonds are broken and structure falls apart."
] | [
"It doesn't necessary have to have a 'springy structure' at the molecular scale to have the elasticity. If it consists of little strings at the molecular scale, thermal motions push at the sides, making the strings wanted to be curled up to a degree. These pushes at the side effectively try to pull inward when the ... |
[
"Mood effects from binaural sound?"
] | [
false
] | I've been hearing for a number of years about this "phenomenon". Sites and products such as I-Doser insist that these effects are real, and have no problem charging you insane amounts for the "doses" (up to 200 bucks for a SUPER SECRET ONE! ) My question to you, is ANY of this close to legitimate or scientifically proven or is it just teenagers listening to static that's really a big fat placebo? | [
"I will try the mp3 (if I still have it) on my current girlfriend tonight and report back. FOR SCIENCE.",
"EDIT: Mission failure. Girlfriend hereafter known as #2 lasted about 3 minutes before giggling uncontrollably while ripping off the headphones and asking me what in the world was I making her listen to.",
... | [
"It's been discussed before, ",
" though I don't believe there is a good scientific consensus. We know that some frequencies impact EEG recordings, but we don't yet understand whether or not it has any implication on mood (other than anecdotes of course). "
] | [
"This would be a lot easier to judge if any of their research were published. Since it's all for-profit, I doubt we'll see any of the research any time soon (if ever). "
] |
[
"Is Gibbs energy of activation same as Activation Energy?"
] | [
false
] | I am solving a problem involving calculation of the activation energy of the and I've read that to calculate that, I need to add the of the reaction and the activation energy. In the problem, the Gibbs energy of activation was given instead of the activation energy. | [
"Activation energy usually refers to the change in internal energy required to overcome a barrier where as the free energy of activation is the activation energy plus the entropy term.",
"Seems like a poorly worded problem."
] | [
"In this case it's the same thing.",
"",
"We normally refer to the Gibbs Free Energy of a system (maximum work a system can do at constant pressure and temperature) to differentiate it from the Helmholtz Free Energy (maximum work the system can do at a constant volume and temperature). Most chemistry work is d... | [
"i thought of it because when transforming the arrhenius equation, an activation energy explicit form will give you Ea = -RTln(K/A) which looks like the change of gibbs energy interpretation."
] |
[
"What stops the gravity-wave-measuring laser beam from being influenced by the gravity wave?"
] | [
false
] | Therefore, if a gravitational wave passed through a detector such as LIGO, presumably it would affect the structure and the light equally. The LIGO structures might contract, but the laser beam would also be bent, resulting in no effective change to the behaviour of the laser beam. To put it another way, if spacetime is represented by a sheet of grid paper, with the gravitational wave detection laser travelling 10 grid spaces and back again, then it doesn't matter whether you curve, bend or scrunch the paper up into a ball - the "laser" still has 10 grid spaces to travel so it wouldn't detect the changing of the paper's structure. Is this reasoning correct? I don't understand how you would be able to use a laser to detect gravitational waves if the waves would influence the laser beam in such a way as to cancel out any change it may otherwise have measured. Note that I am assuming gravitational waves distort spacetime, leaving the distance between atoms unchanged, rather than placing actual pressure on objects and making the atoms temporarily move closer together. If gravitational waves caused atoms to move closer together then presumably you could detect them the same way you detect any other pressure wave (e.g. increase in heat due to friction, piezoelectric effect, etc.) But of course if gravitational waves don't cause atoms to move closer together then the distance between atoms will be the same, so of course the distance the laser light must travel would also remain the same, leading to no detection of the wave. What am I missing? | [
"the \"laser\" still has 10 grid spaces to travel so it wouldn't detect the changing of the paper's structure.\nNote that I am assuming gravitational waves distort spacetime, leaving the distance between atoms unchanged, rather than placing actual pressure on objects and making the atoms temporarily move closer tog... | [
"So in other words what you're saying is, the paper is temporarily having more grid spaces inserted (crammed, if you will) into it so that two points that were 10 grid spaces apart are now 11 grid spaces apart (then shortly afterwards only 9 grid spaces apart, and so on), and you can measure the distance (since 11 ... | [
"I did my MS research for LIGO and I think the easiest way to address what you're talking about is to discuss how a gravitational wave interacts with the test masses (mirrors) of the LIGO interferometers.",
"Remember, an interferometer doesn't tell you how far light has traveled, it tells you about the ",
" bet... |
[
"How does a wax candle burn"
] | [
false
] | I know that the flame causes the wax to melt, and capillary action causes the now liquid wax to move up the wick, protecting it from the flame, and the wax is then vaporized and used as fuel, but what actually happens to the gaseous wax? Why does it produce the light and heat associated with a flame? | [
"This is an odd question. I hope my chemical background is enough to give you the answer you want.",
"Candle wax is usually just a mixture of hydrocarbons in the C20-C40 carbon range. They're really simple molecules. They're waxy because of the length of the molecules. If they were shorter, they'd be liquid (C8 i... | [
"Technically, the wax combusts in gas phase, it is liquefied, drawn into the wick, vaporized, and combusts as a vapor. The smoke will contain CO2, CO, H2O, and various unburned hydrocarbons. "
] | [
"Yup. Most of the light actually comes from incandescent soot, too. Because waxes are largeish molecules, they tend to burn incompletely - the hydrogen gets stripped off easily, and then the carbon backbones tends to agglomerate to form soot - these particles are then heated by the flame and emit light due to bla... |
[
"Why can't I use lenses to make something hotter than the source itself?"
] | [
false
] | I was reading What If? from xkcd when I stumbled on It says it is impossible to burn something using moonlight because the source (Moon) is not hot enough to start a fire. Why? | [
"When the single point is hotter than the source, it starts radiating light back at the source. A lens is a passive device, remember - it takes no energy to operate, so the light must flow equally in both directions. If you heat something with a magnifying glass under the sun until it's as hot as the sun, it starts... | [
"Some users, like ",
"u/Jake0024",
", make the correct argument from thermodynamics that heat travels from hot to cold. What is unsatisfying about this argument is that it goes against our intuition about how lenses work. After all, can't we just focus an image of the moon down to an arbitrarily small size? And... | [
"This thread has a large number of responses simply restating passages from the link in the original post, low-effort assertions of fact, speculating on causes, or giving anecdotes, which have been removed. Please keep top-level comments to detailed, expert explanations of ",
" this phenomenon does or does not oc... |
[
"Can mosquitos spread COVID-19?"
] | [
false
] | null | [
"Very unlikely. This is a respiratory virus, and the levels of viremia are much too low for any arthropod vector (mosquitoes, biting flies, gnats, etc) to ingest enough to carry an infection mechanically or biologically. More to the point, none of the coronaviruses that I'm familiar with have insects as biologic ve... | [
"Extremelly, extremelly unlikely. For the same reason mosquitoes do not spread HIV. The vast majority of mosquito borne diseases are not transmitted by the mosquito injecting infected blood from one person to another, the viruses actually have to infect the mosquitoes. That's why dengue, zika, chikungunya tests in ... | [
"This is a majority of the answer. Typically mosquito borne diseases are spread through blood(obviously). So you’re not going to catch anything with respiratory or digestive from them. ",
"On top of that, for a mosquito to vector a disease it has to be able to survive in the mosquitos own digestive tract. Not jus... |
[
"What are goat's pupils horizontal? What purpose do they serve?"
] | [
false
] | null | [
"Their predators are almost never attacking from above or beneath them. Natural selection has made detection of movement on the the same plane high priority. The same goes for deer and many prey animals. The shape of the pupil gives them a sort of panoramic view of their surroundings so they can see what is importa... | [
"Follow up question. Why are octopus pupils horizontal?"
] | [
"I did some sleuthing and found ",
"this",
". It says:",
"The narrower the pupil in relation to the horizon, the greater the accuracy of depth perception is in the peripheral vision of the animal. The perception of depth must be considered with these animals who spend their time evading predators in a rugged... |
[
"Why does soap lather better in hot water? What kind of chemical reaction is going on?"
] | [
false
] | [deleted] | [
"Solubility is dependent on temperature, so at a higher temperature more soap can dissolve. A quick ",
"google",
" can give you a lot of information.",
"No chemical reactions take place when dissolving soap in water, it is a physical process."
] | [
"Also for more info check this page: en.Wikipedia.org/wiki/hard_water"
] | [
"When we create huge amounts of CO2 It goes to the atmosphere and dissolves with rain and creates a week acid called H2CO3. When the acidic rain come to the earth, It reacts with Calcium carbonate (Limestone) and when they reacts they create Ca(HCO3)2 that is the reason for making water hard. In the hard water the ... |
[
"I'm familiar with acoustic and inertial positioning in subsea environments. How does positioning work in space ?"
] | [
false
] | [deleted] | [
"Generally, optically or by radio."
] | [
"Why would there be no inertia outside of a gravitational field???? ",
"Oh wait, we can't really escape from gravitational fields…"
] | [
"If I understand correctly, inertial navigation systems rely on a large gravitational field."
] |
[
"Is there anything specific that pushes a person over the line from \"eccentric\" to \"mentally ill?\""
] | [
false
] | -- About 15 people have replied "Amount of money" so if that's your only (non-scientific) response, please don't bother. | [
"its very vague and subjective, but the best rule of thumb that you can apply to deciding if anything is a disease is ;",
"\" Does it impact negatively on somebodies life?\"",
"Its not foolproof but its a pretty good guide. If it doesn't effect their \"wellbeing\" then leave them alone, they're not sick."
] | [
"As a psychiatrist, this is absolutely the most accurate answer to this question."
] | [
"The short answer is: almost nothing whatsoever. Currently, psychiatric disorders are diagnosed using the ",
"Diagnostic and Statistical Manual of Mental Disorders, 4th edition",
" (DSM-IV), which is supposed to provide empirical, standardized methods for diagnosing various mental illnesses. However, the DSM st... |
[
"What is inside the core of each of the Gas Giants?"
] | [
false
] | null | [
"We're not sure.",
"Heavy elements should sink to the bottom, and given how we think planets form there was likely a large (~45 Earth mass) rocky planet that began collecting a lot of gas and became Jupiter. Compression should also have made it rather hot and kept it insulated; conventional wisdom says it is abou... | [
"That was the metallic hydrogen I mentioned. If you look at the periodic table hydrogen is at the top of the group 1 metals (lithium, sodium etc) but we never see the metallic phase on Earth.",
"This might be liquid or solid - we're not sure because the pressures are unreachable even in the lab.",
"Denser eleme... | [
"The following is the relevant bits of this.",
"Following probe parachute deployment, six science instruments on the probe collected data throughout 97 miles (156 km) of the descent. During that time, the probe endured severe winds, periods of intense cold and heat and strong turbulence. The extreme temperatures ... |
[
"If you jumped onto an electric fence and grabbed on without touching the ground, would you get shocked? And would you be able to keep climbing or would you be continually shocked?"
] | [
false
] | Just curious, not trying into break into anything. | [
"The few electric fences I have encountered were pulsed DC powered. A high voltage charge is accumulated in the power supply and discharged at intervals into the wires. You would likely feel an attenuated shock every time the fence is powered because your body acts like a capacitor and it takes a little current to ... | [
"I've seen these DC fences for horses, and they usually alternate hot and ground wires.",
"Touching the ground wires was safe. Getting my little brother to touch the hot wires was fun."
] | [
"No, In an electric fence you have three resistances to take into account, the wire, the animal and the ground. You always want the animal to have the highest resistance, since this will lead to the highest voltage drop across the animal. The voltage drop is what you feel as \"",
"\", which is usually what you wa... |
[
"Do people with a higher occurrence of AT pairs in their genes have a higher risk for mutation than those with GC pairs?"
] | [
false
] | [deleted] | [
"This is an interesting question, and it's one that's the subject of research right now.",
"The short answer is that all kinds of mutations can happen, and the frequency of a mutation type depends on a number of factors. Interestingly, different types of cancer seem to have different \"mutational signatures\" -- ... | [
"I absolutely think that each nucleotide has a different probability of being modified (which will then lead to replication errors and then mutation). Hydrogen bonds have little to do with the modification aspect. It's more about chemical structure.",
"\nRegarding mutation, sooo much of our genome is referred to ... | [
"Would you be able to confirm or deny that each cancer has a different type of \"mutational signature\" because of the genes that are turned on in that area of the body?"
] |
[
"If you know the frequency or volume of sound produced by moving air, can you determine how fast the air is moving?"
] | [
false
] | null | [
"Under normal conditions, a given frequency and intensity will vibrate the air such that the chain of collisions between air molecules will be 340 m/s. This is the speed of sound.",
"Analogously, light may arrive in different colors (frequencies), but the speed is the same."
] | [
"To add to this, the speed of sound also varies with temperature and humidity. At 0 degrees celsius the speed of sound in air is 331m/s. The higher the temperature the faster the speed. ",
" sound = 331m/s + 0.6T"
] | [
"Interesting question. There is not any physical law that will give a dorect answer to that, but I'm sure there must be several scholarly articles on modelling that relation, although they are most likely geometry or material-specific.\nThe pitch that comes out of, for example, a flute is heavily influenced by the ... |
[
"What is the name of the effect where rays of light become visible when reflected off particles?"
] | [
false
] | null | [
"Mie was German."
] | [
"Scattering"
] | [
"Well, yes, that, but there's a technical term for it, it's named after a person."
] |
[
"Why does the pupil dilate when in heavier thought?"
] | [
false
] | null | [
"Dilatation can happen when seeing certain images, either interesting images (Hess & Polt 1960), big list of number,...",
"It can also happen when you try to analyse a complicated sentence, or focusing attention (Beatty 1982, Beatty & lucero-Wagoner 2000). It's called \"task-evoked pupillary response\".",
"Kahn... | [
"I found ",
"this",
" review claiming that the LC has direct, inhibitory projections to the Edinger-Westphal nucleus (EWN), which is well-understood to constrict the pupil. So, higher activity in LC reduces activity in EWN, which then dilates the pupil and would explain the close correlation. From the article:"... | [
"I thought of the question after reading Kahneman's ",
", where he mentions the pupils response to certain emotionally or mentally charged stimuli.",
"Essentially, though, it doesn't have anything to do with any benefits that added light would confer when presented with said stimuli? It's just a response of the... |
[
"What is happening when something becomes \"second nature\" or habit to us, such as tying our shoes? Does it move to a different part of our brain?"
] | [
false
] | I'm referring to when people seem to do things automatically after many years of learning them. EXAMPLE: When we first learn to drive, we concentrate all our brainpower on doing everything correctly. A few years later we barely have to think about pressing the gas, brake, steering, etc. Does this information move to the "back" of our brain? Does it get filtered out differently as we get used to these things? | [
"I think you're describing the formation of corticocortical connections. When you're first learning something consciously, you rely heavily on a part of your brain called the hippocampus to coordinate activity between the neurons required for the task. If you call upon the brain to do this frequently enough, thos... | [
"I believe this is exactly what I was looking for. Thank you!!"
] | [
"This learning process is performed in the ",
"cerebellum",
", which underlies the predictive motor movements, postures, and reflexes that we perform every day (and yes, it's actually in the back of your brain). I don't have time right now to explain it, but the learning process in the cerebellum and the circu... |
[
"Genetic determinism vs. Free will"
] | [
false
] | [deleted] | [
"Twin studies offer one type of evidence for the inheritability of certain personality traits. ",
"If you are interested in this subject I would suggest reading a book called The Agile Gene. It is about how nature (genetic predispositions/traits) is turned on by nurture (environment). It really delves into the... | [
"There's lots of literature surrounding criminal behaviour in people with Jacob's Syndrome (XYY) Many studies performed in in prisons. I would be interested if anyone found hard evidence to suggest that this was linked to criminal behaviour."
] | [
"I certainly agree with this statement, but what I think the author was really getting at was not the degree of genetic difference between one person and another, rather, that our environment influences how our genes are expressed. Genes, although implacably determinist in nature (always coding for the same enzyme... |
[
"If we found the link or solution of the distribution of prime numbers, what could we do with that information?"
] | [
false
] | Would it lead to other mathematical breakthroughs or technological increases? | [
"It would almost assuredly lead to more advanced and more powerful mathematics. The ",
"Riemann Hypothesis",
" is a question about understanding the distribution of primes. If it is proven, some other theorems that depend on it will also be proved, but this isn't the main impact. Everything tells us that our cu... | [
"While there have been cases, the more fundamental concept is that proving something has a lot more power and value than simply knowing it is true.",
"The math developed to prove this would be useful for many other problems, even if it doesn't tell us anything we don't already know about primes. ",
"Its about t... | [
"Many have, yes - ",
"see link",
". 10 trillion non-trivial zeros have been checked, and each and every one satisfies Riemann's hypothesis. Most mathematicians expect the Riemann hypothesis to be true. Sadly, many also do not expect to see it proven while they live."
] |
[
"AskScience AMA Series: I'm Brian Greene, theoretical physicist, mathematician, and string theorist, and co-founder of the World Science Festival. AMA!"
] | [
false
] | I'm Brian Greene, professor of physics and mathematics at Columbia University and the Director of the university's Center of Theoretical Physics. I am also the co-founder of the , an organization that creates novel, multimedia experience to bring science to general audiences. My scientific research focuses on the search for Einstein's dream of a unified theory, which for decades has inspired me to work on string theory. For much of that time I have helped develop the possibility that the universe may have more than three dimensions of space. I'm also an author, having written four books for adults, , , , and just recently, . and were both adapted into NOVA PBS mini-series, which I hosted, and a short story I wrote, , was adapted into a live performance with an original score by Philip Glass. Last May, my work for the stage , which explores Einstein's discovery of the General Theory, was broadcast nationally on PBS. These days, in addition to physics research, I'm working on a television adaptation of Until the End of Time as well as various science programs that the World Science Festival is producing. I'm originally from New York and went to Stuyvesant High School, then studied physics at Harvard, graduating in 1984. After earning my doctorate at Magdalen College at the University of Oxford in 1987, I moved to Harvard as a postdoc, and then to Cornell as a junior faculty member. I have been professor mathematics and physics at Columbia University since 1996. I'll be here at 11 a.m. ET (15 UT), AMA! Username: novapbs | [
"Professor Greene,",
"I read your book ",
" when I was younger and very much enjoyed it. Unfortunately, I haven't reading as much on the topic of string theory since I left university.",
"So are there any new developments or big changes on the field of string theory in the last 15 or so years?"
] | [
"Well, I am all for healthy debate. And, look, I too am a string theory skeptic. It may sound strange to hear that coming from me. But the fact is, my view of what's right and wrong is ultimately governed by experiment/observation. So, everyone SHOULD be skeptical of ANY theory until such data is available."
] | [
"A great many advances in past 20 years---understanding the disorder or entropy in black holes, finding exact formulations of the theory, gaining hints regarding the basic structure of spacetime. What we lack is experimental/observational evidence."
] |
[
"What is the truth about GMO'S?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"This topic has been widely discussed. Have a read through these other discussions and if you've got a more specific question after, we'd love to add it!",
"http://www.reddit.com/r/askscience/comments/... | [
"Thank you for the links. I didn't want to beat a dead horse I just wanted to learn."
] | [
"Sure, it's no problem. We just try to avoid too many repeat questions because it can frustrate our panelists and users. If you think of another question after reading through the other posts, we'd love to hear it."
] |
[
"If you streamed a video of a white screen and a video of a vibrant tropical landscape, both in 1080p, would they render at equal speeds or would the white screen render faster?"
] | [
false
] | [deleted] | [
"It usually depends entirely on the compression algorithm used on the video. If a key-frame & delta algorithm is used, then the white video would download much faster.",
"Key-frame & delta compression works as such (ignoring individual frame compression):",
"Video has an initial key-frame, which is stored as th... | [
"In addition, if individual frames are compressed too then the white keyframe could also have a very small size (since the only information needed to specify the whole frame is '1920x1080 pixels of white', rather than needing to describe 2 million individual pixels). "
] | [
"On PCs the decoding is often done by an ASIC on the graphics card. There will be no difference in the decode time on the ASIC.",
"For software decoding:"
] |
[
"Is there a solution to the twin paradox not related to acceleration?"
] | [
false
] | Most of the answers I have read from previous posts point to acceleration being the reason for the twins aging at different rates; however, it appears that acceleration is a common explanation because it is simple to understand but is a misconception. I am unable to wrap my mind around how the two frames are different if acceleration is not the driver for the difference. | [
"The trick is that there are actually three frames. A frame of reference moves at a constant speed in a fixed direction. Imagine it like a bunch of trains on parallel tracks, some moving forwards, some moving backwards, all at different fixed speeds. The passengers can't slow down or speed up the trains, but they "... | [
"A closed universe breaks the symmetry in a different way, it has a natural preferred reference frame. This frame is the one in which the universe is smaller than any other frame (yes, smaller! Any moving observer will be Lorentz contracted, as will as their rulers, hence they would measure the universe to be bigge... | [
"Okay, so you're saying you have two twins initially separated by some distance, and they both accelerate towards towards each other at the same rate, until they meet?",
"Here it is still symmetric, and both will see the other as time dilated. This doesn't cause a contradiction, because their times weren't synchr... |
[
"Does the confirmation of the Higgs Boson have any implications for String Theory? Does it strengthen it, weaken it, or have no effect?"
] | [
false
] | [deleted] | [
"Little effect, there are some theories with large extra dimensions that would require no Higgs (they have their own mechanism producing the same end effect without adding a boson), so those theories are probably feeling it a bit, but otherwise it sheds little light on the landscape. "
] | [
"Good point, yes the Minimal SUSY extension to the Standard Model (MSSM) has been under pressure for a while due to it usually predicting a lower Higgs mass, but this has been true since earlier accelerators put a lower bound on the Higgs mass that was higher than the desired mass for MSSM. However, this is more a ... | [
"I believe most string theories were already under the assumption that there was a higgs boson. The particular mass it was found at puts in more constraints on possible string theories. It does not have a strong effect on string theories in general."
] |
[
"Are ultrasounds dangerous?"
] | [
false
] | I've had three on three different parts of my body over the past month, and now I'm worried that I've had too many and will do some kind of long-term damage. Is this likely? Edit: Thank you very much everyone. I'm learning a lot and am finding the conversation more interesting than I imagined I would! | [
"While they are generally safe, using only high frequency sound-waves as an imaging method with no obvious risk (like ionising radiation with x-rays/CT for example), sound waves are still a form of energy and have the potential to cause tissue damage through heating. The risk however is very small and a very long e... | [
"You should be fine. I mainly wanted to make the point that there is a potential risk (though it would require a very high exposure) as many people assume that just being sound-waves means there is no possible risk."
] | [
"To be pedantic, I think doing to a concert might be harmful to your hearing in some small but possibly significant way."
] |
[
"In the lastest xkcd what-if?, it was question of how to prevent the slowing of the earth's rotation, by acting directly on the earth. What if we bombarded the moon instead, bringing it closer to the earth, and tidally locking it on a 24 hour period?"
] | [
false
] | null | [
"How intense the bombardment would need to be?",
"This is a drastic change in the orbital energy of the moon, so the scale of things is hitting the moon with a similar mass as itself at a similar speed to itself in the opposite direction.",
"How bad the effect of the tidal force would be?",
"The tidal force i... | [
"I had a couple thoughts when reading the above. First, would putting the Moon in a geosynchronous orbit of the Earth put it within the Roche limit and cause the Moon to break up? Turns out that no, it wouldn't. It's new orbit would still be about a factor of 2 times the Roche limit. ",
"http://en.wikipedia.org/w... | [
"The moon is 0.0123 earths massive, so the barycentre is at 1.23% of the way between the centre of the earth and the centre of the moon? Is that as simple as that?",
"It's almost as simple as that. ",
"Here's the equation",
". It will be 0.0123/(1+0.0123) of the way from the earth center to the moon center ... |
[
"When I'm carsick dad always says to open the window and breathe fresh air. Does this actually help? How?"
] | [
false
] | as far as i'm aware carsickness is due to the conflict between the inner ear and eyes, so i'm not quite sure how the air would make a difference. i've googled this to no avail. edit: many thanks for your help, guys! | [
"I find that cold air on my face reduces nausea... this can be in a car (by opening a window) or in a plane (by turning the air jet above the seat onto my face)."
] | [
"I'll bet that you looked out the window when you were breathing the fresh air... thus averting the conflict between the motion cues sensed by your inner ear, and what you saw.",
"Also, it probably got your mind off the carsickness."
] | [
"I guess feeling the wind helps your body to believe the fact that you're moving and reduces the conflict between the inner ear and the eyes."
] |
[
"What is the main reason we cannot keep Great White Sharks in captivity?"
] | [
false
] | I've read briefly on the topic on Wikipedia but was curious as to whether there was some scientific backing as to why it is so difficult to keep this particular shark in captivity. My assumption is that their eating habits don't allow it but I'm hopeful there's a more solid reason. | [
"This is not my area expertise, but I'm a bit of a shark enthusiast and I just happen to love a vet so I can try to answer this for you. I don't think there is a well defined reason, though.",
"First, some aquariums have managed to keep Great Whites in captivity for extended periods of time. From my reading, I be... | [
"One possible reason for the stress is that in the wild, Great Whites are known to travel huge distances. Great Whites tagged near South Africa have been recovered near Australia less than a year later. It is thought that they may migrate there for feeding or mating."
] | [
"I think they would eat way too much. Also they need a lot of space. Better let them swim free. "
] |
[
"Why does the dengue vaccine work best on people who've been infected with at least one strain of dengue fever before?"
] | [
false
] | null | [
"Dengue is an interesting infection in that the second time you get it, you generally have ",
" symptoms (sometimes life threatening) than the first time are infected. Because getting a vaccine mimics getting an infection, giving the vaccine to someone who has never had Dengue actually ",
" their risk for sever... | [
"Thank you for your detailed answer! I had dengue about a month ago and after I recovered, the doctor told me that now I've had the infection once (it was my first dengue infection), the vaccine is now safe for me to take and I've wondered why the dengue vaccine can't just protect you from all the strains before yo... | [
"Hi, did you end up getting the vaccine? I live in Puerto Rico and currently have Dengue. I’m freaked out about getting dengue again because I’ve read it can be significantly more life threatening if you get it a second tome. Any thoughts? Thanks!"
] |
[
"If neutrino oscillations imply that neutrinos have mass, then why doesn't the frequency or phase of photons imply that they have mass?"
] | [
false
] | As far as I'm aware, neutrino oscillations imply that neutrinos have mass because if neutrinos have a time dependent state then time is passing in their frame, meaning that they're not going at the speed of light, meaning they have mass. Why can't this be extended to the phase of a photon which changes over time? | [
"Neutrino oscillations imply that neutrinos have mass because in order to detectably change into a different flavour, at least one of each possible pair of flavours must have nonzero mass (otherwise they would have equal mass). Photons don't change into fundamentally different particles as they whizz along so they ... | [
"What arble said. To put it in slightly different words, it is because neutrino flavor oscillations are ",
" that we know at least 2 neutrinos must be massive (and all 3 neutrinos cannot have the same mass; it is still possible for the lightest neutrino to be strictly massless). If neutrino oscillation did not ... | [
"Thanks, what you and hikaruzero have said has cleared that up for me."
] |
[
"Can prions affect non-nervous tissue?"
] | [
false
] | If prions are simply misfolded proteins, can these misfolded proteins appear in non-nervous tissue? Is it possible that there are prions that mainly affect non-nervous tissue such as muscle tissue? | [
"Yes, the main determining factor is whether the prion protein is expressed by a certain cell type. So the prion that causes mad cow disease is found in muscle cells--hence why it is dangerous to eat beef that is potentially infected with the protein. The neurodegenerative process is what is lethal, though."
] | [
"There is evidence that there are infectious prions in the skeletal muscle as well."
] | [
"I was under the impression that CJDv was generally from the meat becoming tainted with brain matter during slaughter."
] |
[
"What is the difference between an alloy and a composite?"
] | [
false
] | null | [
"I've been rereading a book from one of my materials-science classes, and it has a good explanation.",
"An ",
", by definition, is a metallic solid or liquid formed from an intimate combination of two or more elements. By \"intimate combination,\" we mean either a liquid or solid solution.",
"Then, in contras... | [
"An alloy is a combination of two or more metals that have been melted and evenly blended together. A composite is a material made up of two or more separate materials (not just metal) that have been woven, glued, or adhered together in some other way."
] | [
"I think it's also valuable to define the difference between an in-situ and ex-situ composite. In-situ are formed similar to steel; you use phase separations, thermodynamics, or some sort of reaction to wind up with two (or more) distinct phases. Ex-situ would be where your second phase is added in its final form a... |
[
"Why do our noses get runny when we cry?"
] | [
false
] | [deleted] | [
"Your tear ducts drain into your sinuses, which as you can imagine, get runny.",
"Spicy food can cause your eyes to water, but also spices are irritants to your nose, and causes it to produce mucus to try to get rid of the irritants(Also why you sneeze)."
] | [
"As was already said, you have what is called a Nasolacrimal duct that goes directly to the back of the nose, any time there is an excess of tears produced by the lacrimal ducts, the nasolacrimal ducts take the rest and cause the runny nose."
] | [
"Very interesting, thank you!"
] |
[
"Why aren't turbine engines used to power cars instead of standard internal combustion engines?"
] | [
false
] | As i understand it, turbines are much much more efficient Discarding the variable of cost aside, why aren't they? | [
"Not only more efficient, but quieter, and they could use multiple types of fuel.",
"The main excuses were throttle lag (pressing the accelerator, and it takes a few seconds for the turbine to wind up and increase power), and differences in function, like stalling if you floored the pedal too soon.",
"But it wa... | [
"Throttle lag is not a major concern. I worked quite a bit on the turbine engine used in the M1 Abrams. There is very little throttle lag in that setup. In fact, an Abrams will accelerate faster than a Hummer.",
"I would point out the main issue is maintenance. A turbine engine is simple in concept, but diffi... | [
"They scale up well, but not so well down. This is assuming simple designs. Efficiency can be adjusted by varying the angle of attack of the blades but that adds a lot of complexity for an automotive application."
] |
[
"Is it possible that the human race will keep getting taller in the future?"
] | [
false
] | [deleted] | [
"There is a limit to how tall humans can get: \nMass increases with the cube of the size, but bone strength increases with the cross section of the bone and thus with the square of the size.",
"At some point we would be so heavy we could not move without snapping our legs."
] | [
"No, it isn't. The cardiovascular and skeletal systems of the average human would have to do some impressive evolution to support people that tall, and short of some pretty severe mass die-offs (somehow hitting only people under the 1-5% height percentile), 200 years is far too small a timeframe for this to happen.... | [
"If we continue to have enough food that it doesn't limit reproduction in tall people then we may. If there is no natural selection either way, sexual selection for tall people will gradually increase our height. Of course, culture can always change and short people may be favored if we are in a famine or low on ... |
[
"Could Curiosity (or some other Mars lander) 'populate' Mars with life?"
] | [
false
] | I am not sure if bacteria (or other micro-organisms) could survive the flight through space and subsequent re-entry, but if so, considering they have found signs of water, could we essentially begin life on Mars by our actions? (This is of course assuming that life does not already exist and just has not been found). If I have the wrong flair for this question, let me know and I'll change it. I found at least 3 possible categories this could go under. | [
"There is almost certainly life on Mars. Life that we sent there.",
"We know for a fact that some organisms are capable of surviving the rigors of space (hard vacuum, radiation) because they've been found on spacecraft that have returned from the Moon.",
"The issue is that they can only survive that way in a ",... | [
"Yep, and this is a serious issue with concepts of missions to Europa and other icy moons. On Mars, there is definitely surviving microbes from Earth, but they likely can't reproduce; they're in a state between living and dead. However, on a Europa mission, if any Earth-microorganism makes contact with the water, s... | [
"I just find it interesting that we find microbial life in the most inhospitable places on Planet Earth. It makes me wonder if Curiosity just had a shovel if there isn't an ecosystem teeming beneath Mars.",
"My reason for asking this question was the hypothetical situation where we discover water just under Mars ... |
[
"Is there any application of the intergral of displacement in regards to time, ie the meter-second?"
] | [
false
] | [deleted] | [
"The integral of displacement with respect to time has got a name, called ",
" although it does have limited use in physics. It's mainly used for computing costs and such given rates dependent upon time and displacement. But, I can't do it justice in this comment so here's a much better website than my rambly exp... | [
"One practical use is in PID control systems. I won't try to explain it in detail, but the integral you're asking about, along with the velocity and instantaneous displacement, is used basically to move a system (such as a robot's joint) to a desired state. Here's the wikipedia article: ",
"http://en.wikipedia.or... | [
"Great link, thanks for that. I find the author's example to be a bit of a stretch, though. Wouldn't something like \"man-hours\" or... I don't know, power usage, make for a better example?",
"I think that I get it, but the example isn't really making the concept easier to understand."
] |
[
"Is carbon smaller when it is reduced or oxidized?"
] | [
false
] | Thank you in advance for your reply! | [
"The bond length in methane is ",
"109 pm",
" and the bond length is CO2 is ",
"116 pm",
". Does that answer your question?"
] | [
"One of those links is to Wikipedia. The other is to two drunk puppies. That creates other questions..."
] | [
"Oops. Thank you. Apparently I am bad at copying and pasting..."
] |
[
"What would a laser \"gun\" sound like? What about other \"future\" weapons like plasma guns, photon cannons, energy blasts etc.?"
] | [
false
] | null | [
"A simple 'photon cannon' exists in your home right now (I'm guessing), and is usually called a torch. What noise does it make when you switch it on?"
] | [
"Laser guns would likely not make a sound. Maybe a electrical hum of sorts depending on how the device was powered. Photon cannons are just science fiction. As for plasma.... I'm not quite sure."
] | [
"the click of the trigger, followed by whatever you want it to sound like.",
"best example? electric cars. like gas powered cars and gas powered rifles make a big boom, electric cars and electric weapons essentially... make no noise."
] |
[
"Physics time difference between two points in the galaxy."
] | [
false
] | Given: Instant travel and communication between planets. Astronaut travels to planet X on edge of Milky Way Galaxy and tries to make contact with Earth. Is it even possible or will time be moving at different rates? I don't know which reference to use planet x and Earth have the same angular velocity, but their tangential velocity is different. Wish I could be poetic but you'll have to settle for prose, having a hard enough time getting this question out coherently, hopefully this isn't gibberish. | [
"Typical stellar orbital speeds range from 210-240kps. There would be almost no effect caused by time dilation. "
] | [
"There will be an additional effect from the fact that earth will be deeper in the potential of the Galaxy by a bit, and therefore time on earth will seem to run slightly slower from the perspective of planet X. But again, the effect is very, very small. Time on, say, GPS satellites runs a little faster than it doe... | [
"I don't think you understand time dilatation well. It all has to do with relativity. ",
"this",
" will explain it."
] |
[
"If water was suddenly exposed to the vacuum of space, how rapidly would it freeze?"
] | [
false
] | For our hypothetical scenario let's say a liter of water at room temp for the ISS was taken outside (not sprayed, but released in a way that wouldn't cause dispersion) and exposed to vacuum, how long would it take to freeze? Movies like the dramatic "instant freeze" effect because space is supposed to be cold. But if vacuum is actually an excellent insulator wouldn't it slow heat loss? Bonus question my dad had during our discussion: Would water disperse more readily in a vacuum and microgravity environment than it would in a microgravity environment with atmosphere? I said it wouldn't be significantly different because water's surface tension is a result of it's cohesive properties which should operate regardless of atmosphere. EDIT: Thanks for all the great responses people! Learned quite a bit more on the matter than expected! | [
"Water would definitely not \"instant freeze\" in space. In fact it would instantly boil!",
"The complete lack of pressure immediately lowers the boiling point of the water, turning it into vapor. This takes care of your dad's surface tension question as well: it's actually impossible for water to exist as a liqu... | [
"The first part is a tough question. You'll have to defer to someone else's expertise as I do not have a definitive answer to that question. \nIt is not within my scope.",
"However to your Dad's bonus question, the microgravity with vacuum vs microgravity in atmosphere there is a definitive answer.\nThe micrograv... | [
"Well, sublimation is the process of a solid transforming directly into gas, so you're not asking quite the correct question. But if a small quantity of water was suddenly exposed to space, I suppose that the answer to your question would depend on how much radiant heat (the sun) it was exposed to. In total shadow,... |
[
"Anybody know anything about PBC?"
] | [
false
] | null | [
"If you want advice on how to help an ill person, that's medical advice too - please ask a doctor, not strangers on the internet. Have you tried calling her doctor?"
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"medical advice",
"/r/AskScience",
"Please see our ",
"guidelines."
] | [
"Where can I post this?"
] |
[
"What does it mean to break the Sound Barrier?"
] | [
false
] | null | [
"It means that the object is travelling faster than sound propagates through that medium.",
"It doesn't mean you hear ",
", but if something emitted sounds behind you, they'd never reach you.",
"You can still travel ",
" the compression waves (sounds) coming toward you. "
] | [
"That kinda makes sense...",
"When you travel into the compression waves... is that how theres this white poof coming out when he fell? Almost like that superman flying scene?"
] | [
"I assume you're referring to the redbull jump as of late? ",
"Honestly, I haven't seen it. "
] |
[
"How has the homeless population of the world not been decimated by the Corona Virus?"
] | [
false
] | null | [
"This is a scientific based question how does that make any sense when there is an absolute definite scientific answer? There is a reason the homeless are doing better and most likely it's because of their immune systems having to cope with them eating out of dumpsters for years on end and living in filth. This que... | [
"This is a scientific based question how does that make any sense when there is an absolute definite scientific answer? There is a reason the homeless are doing better and most likely it's because of their immune systems having to cope with them eating out of dumpsters for years on end and living in filth. This que... | [
"Questions based on discussion, speculation, or opinion are better suited for ",
"r/asksciencediscussion"
] |
[
"Why are some axes rotationally stable but not others"
] | [
false
] | A few of us in the lab have been thinking about this recently. Take something heavy and rectangular, like a box, and flip it in the air. Depending on the axis of rotation the box will either remain spinning in the same orientation, or move chaotically as it tries to realign itself. It seems that the axes that are stable are those with the largest and smallest moments of inertia. If we think about conserving angular momentum, it makes sense that as the box slows down due to energy losses (say from air resistance, although looking on wikipedia this also appears to be true for satellites in space) then rotation will move to the orientation with the largest moment of inertia as L = I *omega, but I don't understand why the axis with smallest moment is also stable. | [
"Asking why is always a funny question, because it is the hardest to answer since you can always ask \"why?\" again. I can describe the mathematics behind this phenomenon and if you believe the math, then you can put faith in the reason it happens.",
"First, the moment of inertia of a rigid object around an orig... | [
"No. It is not due to just symmetry. This will happen with ANY rigid object as long as the 3 principle moments of inertia have sizably different values. "
] | [
"Ok, that's interesting thanks. I do believe the maths!",
"I had figured it was something along those lines. I always like an intuitive reason though. I always find physics so much easier to grasp if you can understand it without resorting to mathematics, good though your explanation is. I guess we can boil it do... |
[
"How do rainbow shots work?"
] | [
false
] | null | [
"When the drink was mixed in the pitcher it wasn't one color, it was layered using liquids of varying densities such that the rainbow was vertical. As he pours slowly from the pitcher you get the top layer first, then the next and so on with some of them mixing slightly as you hit the barrier.",
"I believe that ... | [
"Yeah, I saw that, but why would liquids with different densities mix, then?",
"\nI mean, it's not like water and oil, is it?"
] | [
"They will mix if you give them a little help, but the density and composition difference is enough so that they won't mix immediately. It requires very careful pouring so that they don't mix right away in the original container."
] |
[
"How 'fast' is the Alcubierre drive?"
] | [
false
] | null | [
"There is no limit, in principle, to the speed achievable with an Alcubierre drive. However:",
"It requires negative energy matter, which has not been observed, and the possibility of which is controversial.",
"In a flat spacetime, it also requires the existence of tachyons, which also have not been seen, and ... | [
"Ah, so negative energy generator and blahfuturescience time travel turns out not to be possible. Got it"
] | [
"It just depends how much \"accepted\" physics you are willing to violate."
] |
[
"How exactly does antimatter differ from traditional matter?"
] | [
false
] | null | [
"Taken directly from the wiki on ",
"antimater",
": antimatter is the extension of the concept of the antiparticle to matter, where antimatter is composed of antiparticles in the same way that normal matter is composed of particles. For example, a positron (the antiparticle of the electron or e",
" ) and an a... | [
"There are many different particles. Some, like electrons, protons, and neutrons, form into atoms and molecules. We call these types of things (and the smaller particles they're made up of) 'matter.'",
"Now, particles interact. They merge together, break apart into other parts, etc. One specific interaction i... | [
"What do you mean when you say they will annihilate each other? Truly annihilate or just figuratively? If so, wouldn't that violate the law of conservation of mass?"
] |
[
"Do rockets going to outer space cause any kind of depletion in the Ozone layer?"
] | [
false
] | Does it put a temporary hole that leaks any significant amount of ozone? | [
"No. A few things you need to realize:",
"The atmosphere is held to the Earth by gravity. It is not held there by some giant wall that can be punctured and leak. To get a significant amount of gas in the atmosphere to float off into space, you would have to turn off gravity.",
"The atmosphere is made of gas, wh... | [
"The hole in the ozone has mostly recovered since its worst state in the 1980's.",
"That's not true. This year the ozone hole measured 24.1 million km",
" whereas the largest hole for any year in the 1980's was 22.4 million km",
". The ozone hole really started to form in the 1980's and it is no where near c... | [
"You're absolutely right that some of the gasses would be propelled by the rocket out of their natural position. However it's very unlikely that any of these reach escape velocity. Earth's gravity continues to influence things outside of the atmosphere, too (Quick quip: The reason people on board space stations fee... |
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