title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Do archaea contribute to diseases in humans? Do antibiotics work on them?"
] | [
false
] | null | [
"No they don't contribute to human diseases. No clear examples of archaeal pathogens or parasites are known, but they are mutualists or commensals. One example is the methanogens that inhabit human guts (remeber that it's a very very VERY small percentage compared to rest like Fusobacterium, Bacterioidaes, Prevotel... | [
"Because their natural habitat is in oceans and archaea were initially viewed as extremophiles living in harsh environments, such as hot springs and salt lakes, we don't cross paths often. Besides not all microorganism are infectius. We dont have the same pathogens as animals (we have an immunological system differ... | [
"Archaea don't contribute to human disease (unless you count methanogens and the flatulence they can create as a disease...)",
"Yes a number of antibiotics will kill them. Remember even all eukaryotic life (fungi to plants to humans) evolved from an archaeon and a bacterium fusing. We all share a degree of homolo... |
[
"What happens to the speed of light at absolute zero?"
] | [
false
] | I know that light is a duality and neither a wave or particle but behaves like a hybrid of the two. But if I were to have light shine through something that is at absolute zero would it slow down or continue on at the same speed like nothing happened? | [
"the light would increase the temperature of your mythical absolute zero temperature object."
] | [
"A true vacuum has no temperature. Temperature is based on the kinetic energy of particles, so without particles, there is no temperature."
] | [
"The temperature is essentially the average kinetic energy. If you put something through it that is traveling at the speed of light, the kinetic energy can't be zero. The conditions are mutually exclusive."
] |
[
"How much effect does the amount of gas (weight) i got in my car have on how much milage i get?"
] | [
false
] | So if i decide to refill really late, how much gas do i save on the lower weight of my car with an emptier tank then let's say compaired to a half full tank presuming i drive an average car? | [
"The average car in the USA weighs 4000 pounds. Lets assume the average amount of fuel between fill ups is .75 for most people and 0.25 for you. Finally lets say you have a 12 gallon tank. 12 gallons of gas weighs 72 pounds. 72(0.75-0.25)=36 pounds.",
"36/4000=0.9 you could increase fuel efficiency by about 1% at... | [
"If someone drives their car on a full tank and fill it when it is half empty the average amount of fuel in the tank is .75. If you decide to fill your tank to half and drive to empty that is .25 full on average. So the difference between you and someone who keeps their tank mostly full is half.",
"I am dividing ... | [
"I am very confused by your math. Why are you dividing the tank size in half?"
] |
[
"Can someone please watch this video starting at 0:55 (not the whole thing just the zero-point part) and explain to me why the Casimir Effect works if there is, as the man says, \"on average\" no net change in energy?"
] | [
false
] | EDIT: I rewatched and you might want to start at about 48 secs (i hate when people give you too early times) I'm pretty uneducated. I read in a youtube comment that most of the energy comes from photons, but why are these photons not annihilated by antiprotons? (I read somewhere else that photons are the PRODUCT of ma... | [
"as best I know, the simplest casimir effect works like this: Imagine two metal plates. Since photons must have approximately a wavelength no larger than twice the distance between the plates, and all the associated harmonic waves, there are probabilistically fewer photons between the plates than outside. Since pho... | [
"Or, alternatively, simply right click on the video and click \"copu URL at current time\"."
] | [
"In a way, the casimir effect is a physical model of the difference between countable and uncountable infinities. "
] |
[
"How do scientists \"control\" variables like age, marital status and gender when they analyse their data?"
] | [
false
] | It occurred to me while reading a paper that I have no idea how this is actually done in practice and how effective these measures are at helping researchers come to more useful conclusions. Any info appreciated. | [
"Wow, something I can actually help answer! Alright, I will try to describe the statistics as simply as I can. One of the simplest statistical analyses are one-way ANOVAs in which you are trying to see how much of variable B is accounted for by variable A. As an example let's say we are trying to say that higher sa... | [
"There a few ways:",
"Randomisation. If you take a big enough sample (e. g. 10000 people) and randomise them to two groups. Baseline factors such as gender and age should follow a similar distribution between the two groups. Studies that do this often provide the numbers of certain demographics in the groups of t... | [
"Sometimes you can't. If people volunteering for a trial or something are of a specific group-- men over 30, who are Caucasian-- You simply have to acknowledge your spread wasn't representative. You can design a study to be as representative as possible, but then you may end up with a very small sample size. Depend... |
[
"Why is it that you can \"feel\" bass much more than normal sound?"
] | [
false
] | null | [
"All sounds are compression waves in the air (or for that matter other materials like water and the walls of my apartment). Normally your ears detect these and your brain makes sense of them as sound. Even the smallest compression wave will cause a solid surface to move on an atomic level, and the most powerful c... | [
"The question as to why you notice loud bass and not higher pitches, I'm not totally sure. It could be that humans are more sensitive to higher pitches, so to percieve very low sounds at a similar volume actually requires a more powerful sound wave. It might also have to do with your ability to feel the movement. h... | [
"Well, I hate to do this, but I'll critique the answers so far. One of the best is geist_zero who says \"there's a lot more energy in low frequency sounds of equal amplitude.\" However, if amplitude refers to the extent of forward and backward vibration, as it surely does, this is the opposite of what is true.",
... |
[
"AskScience Theme Day: Science in the News"
] | [
false
] | Greetings everyone! It's time for the second AskScience Theme Day! For theme day, we bring out a fresh topic every week and encourage posters to come up with questions about that topic for our panelists to answer. This week's topic is . We invite posters to find their favorite news stories about scientific phenomena an... | [
"These days they often use DNA. Depends on the country. In many of the developed nations, there are \"stranding response\" teams, or networks of teams, that go check out any large animal that washes up. For instance in the US every section of coastline has a designated stranding response team that responds to any p... | [
"There was the story about the \"Sea Monster\" that washed up one shore the other day. ",
"Supposedly it was some sort of oarfish or shark?",
"How do scientists usually verify these \"mysterious creatures?\" Do you just examine the body for telltale markings or are more advanced tests, like DNA tests, used?"
] | [
"These questions are a bit \"meta\" and not about any specific news story. ",
"Where would you say the cut-of is between making an analogy even laypeople can understand and making sure the analogy holds in all circumstances? ",
"a) Where is the worst case of media misrepresenting a scientific discovery or news ... |
[
"Could prosthetic limbs increase a person's lifespan?"
] | [
false
] | prosthetic legs would mean less blood and less blood pressure needed, one could assume... | [
"While this was my immediate thought when I read the initial question, the follow-up makes it clear that what the OP actually means is, could someone live longer without limbs than with them because of the reduced workload for some organs."
] | [
"Yes because the patient can return to a somewhat normal exercise regime/daily routine. General fitness is very important. The same for late stage degenerative arthritis, it severly impacts the patients walking range, they stay at home in the chair or in bed. This would mean less exposure to sunlight = vitamine d e... | [
"I would think general fitness to be a major factor. With reduced workload you would mean the heart/lungs (oxygenation and pumping) maybe kidney in renal failure (creatine). Liver would not be a problem. If you're that far that an extra leg could kill you because of your class IV COPD, or end stage heart failure th... |
[
"Why hasn't \"Background Cosmic Radiation\" from the big bang disappeared by now?"
] | [
false
] | i was able to follow much of the reasons we've landed on the big bang theory, except for this one. The scientists involved predicted it would be there, and were very excited when they discovered it was indeed there. I don't understand why it hasn't.... fizzled out by now. why is this radiation ever present? | [
"I think the best way to answer your question is by mentioning that the big bang isn't something that happened at a particular point in space. It happened everywhere. The big bang is the event that we associate with the beginning of the expansion of space. To read more on this particular point, see the ",
"WMAP w... | [
"Because we're always receiving more of it from father and farther away. The CMB that could have been locally produced has long since flown off."
] | [
"We didn't predict to see it.",
"This is not correct. Penzias and Wilson didn't know what they were seeing, but the Princeton group (Dicke and Peebles) was planning to looking for it. P&W scooped them by accident.",
"This is described in the Wikipedia article you link."
] |
[
"Are there substances to which all humans are allergic?"
] | [
false
] | [deleted] | [
"No, because allergens are allergens because they only cause a reaction in some individuals. Otherwise, it would be a toxin."
] | [
"I suppose we'd all have an allergic reaction to histamine if we were exposed to it, but that's kinda cheating."
] | [
"Some 90% of humans are allergic to poison oak/poison ivy. My mother is one of the 10%. I ",
" I am as well, but have not tested this hypothesis rigorously. Famously, 3/3 mythbusters interns are not allergic to poison oak.",
"Most, if not all, humans are allergic to mosquito saliva. (don't know which chemical i... |
[
"If the universe is indeed expanding, does that mean the amount of matter there is, which can be converted into energy, is expanding?"
] | [
false
] | I thought about this during my thermodynamics class but didn't want to be that guy who asks this sort of question in class. The first law of thermodynamics states matter/energy cannot be created nor can it be destroyed. If the universe is expanding at some rate, does that not mean the amount of matter/energy has to at ... | [
"No, it is space itself that is expanding, and this only affects systems larger than gravity can affect. e.g. we will always be a galaxy, but we might not always have neighbors "
] | [
"I am a layman, but this is what I have gathered from my time reading AskScience.",
"The Universe is infinite, the amount of matter in it is infinite, and it is expanding, it isn't expanding into anything, because it is infinite in size. ",
"Think of it like this, an infinitely large sheet of latex with a grid ... | [
"its moving apart not growing...Matter can neither be created or destroyed, only transformed. "
] |
[
"Did ancient/medieval people have image of future as we have? If yes, what kind of?"
] | [
false
] | Like in the '70s they thought that by 2000 we will have flying cars and personal robots ant stuff. | [
"To add to the existing answers, medieval / ancient peoples often believed the ",
" was also static. To give one example, stain glass windows from the medieval period often feature figures from a 1000 years ago on a different continent in current clothing styles.",
"Until technology started changing at an rate ... | [
"Their predictions for the future were a bit limited by their minimal understanding of science. There are, of course, people like Nostradamus who made vague predictions of the future. Perhaps you could look into the history of science fiction stories. That might be of interest to you.",
"https://en.wikipedia.org/... | [
"For most of human history, things didn't change from generation to generation. Once we got to the industrial revolution, people could see how the technology changes with each generation, and use that to extrapolate to the future. "
] |
[
"Can a normal airplane fly straight up into space?"
] | [
false
] | null | [
"No. Most normal airplanes have a thrust-to-weight ratio that is below 1, which means that if you pointed an airplane straight up, it would not leave the ground -- the push of the engine is less than the pull of gravity.",
"Planes generate enough energy to fly, but do not have enough thrust to overcome their mass... | [
"No. Jet engines require air to work and will stop running at high altitudes. A plane can do a ",
", going fast then pitching up and being carried by inertia higher than it could reach in level flight. But planes don't go fast enough to coast all the way to space, the flight altitude record for a jet aircraft is ... | [
"Thank you! That makes so much more sense. As you get closer to \"space\" the air starts decreasing/thinning and the plane has nothing to push off of"
] |
[
"Why does it matter if humans are the main cause of the global warming?"
] | [
false
] | null | [
"Such questions are better suited for our newish sistersub ",
"/r/asksciencediscussion",
". Please post there instead."
] | [
"Will do thanks."
] | [
"Do you want me to delete this post?"
] |
[
"How do parrots pronounce sounds that are articulated with lips or teeth?"
] | [
false
] | I was remembering my ex’s parrot, an African grey. He could say my name (Maria, the r is an alveolar tap) perfectly. As far as I know they don’t have the anatomy for that, how do they do it? Not sure whether to flag this as biology or linguistics. | [
"Most birds already have a very complex voicebox, something called a \"syrinx\" that helps them with singing and communication, like our human larynx. Parrots specifically have a pretty complex throat, more or less a second mouth at the back of their beak, connected to a dextrous and bony tongue like a tentacular f... | [
"It's notable that their vocal organ is located at the branch of the trachea effectively giving them 2 vocal organs. It's how songbirds make the complex calls, and how my african grey can make Dolby Atmos level fart sounds."
] | [
"This is just a friendly reminder that the word to use in this context is “piqued” - pronounced the same as peaked. ",
"That is all - carry on."
] |
[
"how does speedtest.net work?"
] | [
false
] | null | [
"It pings a server in your general geographical location to find latency. It then downloads some number of small packets to estimate download speed. Finally it generates some random data and sends it to a server to estimate upload speeds. It does multiple takes and throws out some of the fastest and slowest to get ... | [
"This",
" was one of them when I just ran it."
] | [
"The speed quoted in Mbps (note the lower-case b) is mega",
" per second - you'd need to divide by 8 to get the speed in mega",
" per second (MB/s, capital B). So that explains a good chunk of the difference.",
"For the remaining factor of two... could be the source you're downloading from only has that much ... |
[
"Why is a neutron thrown out of the nucleus in a nuclear fusion with deuterium and tritium?"
] | [
false
] | I have read that in nuclear fusion between deuterium and tritium, a neutron is ejected from the nucleus created. I am interested now, why exactly this happens, why this neutron does not remain simply in the nucleus? | [
"That can happen too but the resulting nucleus, helium-5, is unbound to neutron emission. So it very quickly just decays to a neutron and helium-4."
] | [
"Protons and neutrons fill up nuclear energy levels similar to electrons filling up atomic energy levels. Similarly there are energy \"shells\" although the number of protons/neutrons to fill are not always the same as for electrons.\nThe first shell however is still the same as for electrons which is 2. So 2 proto... | [
"Yes, the energy required to remove the extra neutron is negative."
] |
[
"Einstein's Theory of Relativity is based on the principle that the speed of light is the same for all observers. How did he deduce that and how do we prove it now?"
] | [
false
] | null | [
"For one thing, in order to work Maxwell's equations require that the speed of light be constant. One of Einstein's big leaps was realizing that this wasn't just a mathematical quirk, it represented physical reality. "
] | [
"Einstein didn't ",
" the principle that the speed of light is the same for all observers. Prior to Einstein's theory, the ",
"Michelson–Morley experiment",
" was performed in 1887 by Albert Michelson and Edward Morley at what is now Case Western Reserve University in Cleveland, Ohio.",
"The Michelson–Morl... | [
"You derailed an intelligent discussion with an incorrect grammatical correction, and then you mistook the explanation of your error for a scientific statement. Please step away from the keyboard."
] |
[
"Why aren't lettuces toxic?"
] | [
false
] | [deleted] | [
"Lettuces do contain some defensive compounds to help protect against pests, but none of them are harmful to humans at the concentrations present in the plants.",
"Remember that lettuce is a heavily cultivated plant, so the lettuce we consume today is probably very different from the wild lettuce first cultivated... | [
"I just want to add to that good answer by adding that by saying \"does the lettuce want\" the OP is giving it human characteristics. Lettuce doesn't \"want\" anything, it can't guide it's own evolution even if it had it's own conscious thought. ",
"Lettuce is what it is today because of the selection pressure ... | [
"\"Want\" is a lay way of conveying the relationship to the driving factor. It is a useful stop-gap tool when the driving factor (evolution vs cultivation here) is not simple, or needs to be explained separately. ",
"I have used it to give simple answers to more complex questions, where that factor would lose my ... |
[
"Is there a consensus in the pediatric community on the risk/benefits of adding sweeteners and pleasant flavorings to medication in terms of preventing the occurence of intoxications in children through self-medication?"
] | [
false
] | I'm sort of wondering here. And just to be clear, when I refer to self medication in children, I mean so in the context of accidental unsupervised self-medication (e.g.: " " kind of thing). On the one hand, I notice that some pharmaceuticals will add a variety of edulcorants to child medicine, and even go so far as to ... | [
"So ... emergency pediatrician here ... you are right to identify the risk that children might perceive medicine = candy, or see medicine as normalized such that they might take these by themselves rather than under adult supervision. We definitely see both of these circumstances in the ED.",
"However, the more ... | [
"A very common example is the good ol' cough syrup. Liquid dextromethorphan, the anticough, is the terribly sticky, gooey, and foul tasting part of the cough syrup. I've honestly never seen any that manages to taste even remotely acceptable. Other drugs like ibuprofen can be adequately masked (as in Motrin), but de... | [
"A pharmacist could probably give a better answer, but my understanding is that a lot of the taste reflects the underlying drug taste (ever get a chance to taste cloxacillin suspension, my advice would be to decline ...). There would be a lot of money in making med liquids taste better ... so I assume that the tec... |
[
"Are some genetic traits short-term recessive, but long-term dominant?"
] | [
false
] | [deleted] | [
"It seems like you're confused about what ",
"\"dominant\" and \"recessive\"",
" mean. Let's assume there are two ",
"alleles",
" of some gene ",
" that's involved in eye color, which we'll call A and a [this is not how it works in real life]. Here are the relationships between ",
"genotype",
" and ",... | [
"OP deleted the comment I was initially going to post this in response to, but I spent a bunch of time working through the example with actual numbers (because they still seemed somewhat confused), so I'm just going to post it here:",
"Ok. Let's step through a single generation under Epistaxis's model, using his ... | [
"Would you mind sharing your code? My sense is that your model of genetic inheritance is still not quite accurate, but it'd be easier to see what you're doing if I could see the code."
] |
[
"Is there any substance that is a supercritical fluid at room temperature and normal atmospheric pressure?"
] | [
false
] | [deleted] | [
"According to [Spectra Gases](",
"www.lindegaspr.com/internet.lg.lg.pri/en/images/high_purity_helium_3811_28072.pdf",
"), He-3 has a critical pressure of less than one atm and a critical temperature of 3.3 K, which would technically make it supercritical under ambient conditions. However, the density is so low ... | [
"references?"
] | [
"3.3 K is almost absolute zero. Anything higher temp than that (for He-3) and it is still critical. Room temp is 293 K, so yes."
] |
[
"do we know how chameleons \"see\" Things with two independent eyes? Is it integrated? Side by side?"
] | [
false
] | null | [
"To understand the way they \"see\" things, you can re-frame what you think eyes \"do.\" ",
"Eyes take what is in the world and translate it into something the brain can understand. Chameleons probably perceive the world just as the world is--their brain makes a map of what is 'out there' based on the light that... | [
"This is really good. I think depth perception is another good thought experiment that illustrates this. Imagine explaining to a chameleon how we use the differences in parallax between each eye to estimate depth. We're not consciously doing trigonometry to determine how far away things are, we can ",
". It's bak... | [
"We don't know what a chameleons inner life is like, but imagine you're in a dark cave and are feeling both sides of it with your hands. They move independently but you're still able to form a pretty good idea of what the space around you is shaped like.",
"People think of binocular vision as a series of static i... |
[
"Do ecosystems(biosystems?) exist on the microscopic level and are they significant?"
] | [
false
] | I have a layman's understanding of codependency regarding plants and animals within an ecosystem. If predator X goes extinct, herbivore Y becomes overpopulated leading to the extinction of plant Z...and so on. Yet, I also know about the eradication of smallpox. The two topics never jived with me. I was taught about... | [
"Certainly. Your very own body is also an example of a microbiome where a bunch of bacteria compete to live on/in you. It is also why sometimes antibiotics can be harmful even when they don't harm human cells. Antibiotics can indirectly cause nasty bacteria like C. difficile to colonize by eliminating its competiti... | [
"Microbes are part of the food chain, so yes in terms of the food chain part. For instance, zooplankton might eat smaller zooplankton or phytoplankton. Filter feeders like muscles might eat those zooplankton, etc.. etc.... In other cases you might have fungi/insects/worms eating the bacteria. Since they kind of con... | [
"WP article on ",
"human microbiome",
" has a lot to say about the topic.",
"Predator-prey",
" cycles and ",
"resource competition",
" can be seen in microcosms experiments."
] |
[
"At what windspeed does air no longer cool something but rather heat it up?"
] | [
false
] | I realize this has almost everything to do with shape and surface area, so let's say were talking about a 180 lbs 5 11 person. Is there a way to calculate this? | [
"Whether something is heated or cooled by oncoming air is a function of the object's temperature as well as the oncoming air.",
"As you're talking about a human, let's say you take air at...oh, 60 degrees Fahrenheit and you want it to be noticeably warm when it hits you - say 100 degrees Fahrenheit. This is an e... | [
"Air is heating something that is going very fast mostly because it's going so fast that there is no time for air to get out of the way and it has to compress instead. I would say the lower limit is speed of sound in the air then.",
"Air is always compressible, and always being compressed. The standard breakpoin... | [
"Air is heating something that is going very fast mostly because it's going so fast that there is no time for air to get out of the way and it has to compress instead. I would say the lower limit is speed of sound in the air then."
] |
[
"The Voyager pulsar map not only marks where the Earth is located, but when the Voyager probe was launched. How did we calculate this?"
] | [
false
] | Pulsars make fantastic beacons because they are incredibly reliable on their pulse timing and because they can be markers not only for where in the universe something is but also when it was there. The Voyager pulsar map shows where Earth was located when the probe was launched, but how did we calculate this? I would a... | [
"It's the distances relative to those pulsars, right. A long long time in the future, sure, things will have changed significantly. In fact, pulsars are spinning down over time, so over enough time, the spin periods listed won't even be correct.",
"Also, distances to pulsars have, in general, large errors. The ti... | [
"But are you saying that Earth's relative position to the pulsars in the map haven't changed enough to make the map inaccurate 30ish years later, today? Because that surprises me considering the speed at which everything is moving in space.",
"Once you know the movements you can wind the physics backwards in time... | [
"Yeah I remember reading that one of the hydrogen-coded timings for a pulsar was rounded incorrectly, which bothers me more than it should.",
"But are you saying that Earth's relative position to the pulsars in the map haven't changed enough to make the map inaccurate 30ish years later, today? Because that surpri... |
[
"If a larva is injured, how does that manifest in the adult insect?"
] | [
false
] | For example, if a larva survives some type of attack by a predator and has a large scar, or loses one of its legs or eyes. Is this reflected in the adult form? | [
"It would depend on the species of insect. For example, lets say a butterfly larvae is slightly injured before it begins metamorphosis. Ultimately it would not have an effect on the adult butterfly and here is why: When a butterfly larvae is in the pupae stage of life, it literally breaks down its entire body into ... | [
"Insect larvae that go through complete metamorphosis (egg>larva>pupa>adult) have special parts called imaginal discs which will make all of the adult outer structures (eyes, legs, body, etc.). So if these discs are not damaged, the adult will be normal. However, if these discs are damaged, the larva will prolong... | [
"literally breaks down its entire body into basic building blocks and then grows itself into a butterfly from that basic larvae stew",
"Is there any truth to the urban legend that you can scramble several butterfly pupae together and they will still form viable butterflies?"
] |
[
"If it takes 230 M years to orbit the galaxy, then our sun has only orbited 63 galactic years. I can't understand how such complexity and order can form in just 63 orbits. Are there explanations in galactic evolution theories to explain this?"
] | [
false
] | null | [
"For anybody to respond you would have to explain your reasoning for thinking such a thing. If it is only that it doesn't feel intuitive to you then the only answer is \"tough luck\". There is no law that says the universe has to behave in a way that is intuitive to everyone or even anyone"
] | [
"Yea I suppose it doesn't feel intuitive. I know Galaxies are special due to dark matter and the constant rotation rule for their spin, but still. The galaxies have only spun about 60 times? Wouldn't it still be very early in development? It just feels like it should be much much older."
] | [
"What exactly do you think happened too quickly though? Star formation isn't really a thing that relies on the timescale of the rotation of the galaxy"
] |
[
"How does one get rid of hiccups?"
] | [
false
] | and why isn't there a cure for hiccups? i know that they're more of a cough but i don't know how to get rid of them. all the conventional tactics (hold your breath, drink water, get scared etc) don't work for me. the only strategy that's ever worked for me is drinking a glass of water through a paper towel. and i have ... | [
"Hiccups are a spasm of your diaphragm (the muscle that makes you breathe). The diaphragm is below your lungs and pulls down to make you inhale and push up to make you exhale.",
"There are many tales of how to cure the hiccups. The one I have found effective is to take a deep breath and hold it as long as you c... | [
"thank you! what causes the diaphragm to spasm to begin with?"
] | [
"I have no idea. Sorry. Wish I did. Hopefully someone else will answer this part."
] |
[
"Approximately how long (at the least) does it take for atoms in consumed food, to become part of the human tissue?"
] | [
false
] | Jokingly, a friend said "the lunch of today is the tissue of tomorrow", and it got me thinking; Is there a minimum time, we are fairly certain of, that it will at least take, for some atom from consumed food, to become part of the human tissue? | [
"We are probably talking about proteins here. Carbohydrates and fats are mainly used for energy, and thus their atoms are mostly expelled as carbon dioxide. However proteins are needed as building blocks for bodily proteins. Then the question is, what do we count as \"part of the human body\"? Proteins come in many... | [
"That depends on what you would consider part of the tissue. If intercellular liquid, or water in general, counts, that happens extremely quickly, within minutes."
] | [
"Pardon my lack of clarity. I guess something that consists of cellular matter... muscles, skins, arteries... Does that make sense?"
] |
[
"Do animals understand the notion of rhythm?"
] | [
false
] | null | [
"Some can. It depends on their ability to \"vocal learn\". There's a guy at Duke named Erich Jarvis that does that great work on this. This ",
"article",
" focuses on birds, but has some insight into your question."
] | [
"Actually a lot of timing is based on the heart. Changing heart rates has been related to perception of time. I remember reading somewhere that song tempos were often tied to heart rates too."
] | [
"Actually a lot of timing is based on the heart. Changing heart rates has been related to perception of time. I remember reading somewhere that song tempos were often tied to heart rates too."
] |
[
"Is it possible to have an expanding, technological culture without a trade or cash system?"
] | [
false
] | Sorry if my title is a bit off. Had a hard time thinking of the way to word it. I know this isn't the typical /askscience question. I realize that it's mostly physics type questions asked here. I was hoping to get possible explanations from perhaps some social scientists: psychologists, anthropologists, (Economists,... | [
"Why not try ",
"r/economics",
"?"
] | [
"I don't think this question belongs here.",
"But you might be thinking about a post-scarcity society were technology has made true communism feasible.",
"wiki article.",
"Also, check out Ian Banks' ",
"Culture novels."
] | [
"/r/economics",
" is a haven for dogmatically held beliefs being shouted at each other. There's not the same scientific atmosphere as ",
"/r/askscience",
", and it's much harder to get an open-minded answer."
] |
[
"I recently saw in /r/videos, a simulation of two galaxies colliding. Do we have any imagery of this actually occurring now? If not, what is the closest example?"
] | [
false
] | null | [
"Yes, we have a lot of imagery of this happening.",
"Collage of galactic collisions",
"The Mice Galaxies",
"The Antennae Galaxies"
] | [
"I came to post The Mice. It's one of my favorite images."
] | [
"I know I've seen them before, but I couldn't remember the name. Astronomy pictures are ideal subjects for an image search, though."
] |
[
"Consequences of pressure in deep sea diving"
] | [
false
] | If the atmospheric pressure increases by 1 atm per 10m below the surface, then if we go down far enough (say to 3km) below the surface we could get a pressure of 300 atm (wiki says that at some depths you might even be able to get up to 1000 atm). Would this mean that if an object sank to that level, it would reach a s... | [
"Remember that the pressure comes from all sides. When you're deep, you're being ",
", not ",
". So our hypothetical diver is being pushed from the top just like from the bottom. That means it's still easy to move around.",
"As for control, the new hotnesses for science are autonomous vehicles. Set them g... | [
"Ok, let's look at your question a little more closely. What would be required for something to hover above the surface? Just like on land, it would require a differential: i.e. the force in the upward direction would have to be considerably more than the force in the downward direction.",
"But if water acted l... | [
"There's not much in the way of reading, since these vehicles are pretty much bespoke.",
"Autonomous in this sense means that you program them, and they go down and run your code. Sometimes that code requires them to go on long trips lasting weeks, sometimes that code is a simple search pattern in a couple hundr... |
[
"the most Ideal place to lauch a rocket?"
] | [
false
] | I understand launching at, or near the equator is most beneficial but is that the only place that is the best? what about launching atop the worlds tallest mountain or either one of the poles? Also is a rocket launch the best kind of launching? would launching like SpaceShipOne did be better? | [
"To get into orbit you need to be moving at about 4 miles per second / 7 km per second (or 15,000 miles per hour / 25,000 km per hour.)",
"The Earth is rotating at about 1000 mph / 1600 kph. ",
"If you launch from the equator heading east, then you get a free boost from the Earth's rotation. ",
"(If you launc... | [
"gain of 35 miles (the height of Mt. Everest)",
"TIL Mt. Everest is 35 miles high. Sure you don't meen 30k ft?"
] | [
"Not considering logistical considerations, the defaults are ",
"Chimborazo",
", ",
"Kilimanjaro",
", and New Guinea - they're all at high altitudes and near the equator. ",
"You normally don't want to launch from the poles. "
] |
[
"Do hyperthermophiles (archaea specifically) have a a higher metabolic rate because they thrive at higher temperatures?"
] | [
false
] | Given the tendency of heat to generally increase reaction rate (typically, at least), would this mean that these organisms experience a commensurate increase in metabolism? | [
"As an undergrad, one of my jobs was to culture hypothermophilic archaea (the samples originally came from sea ice in the Arctic Ocean). Their peak temperature for culture was just above the freezing point of water. At this temperature (we grew them in a fridge) the grew and divided at rates comparable to any of ... | [
"Keep in mind the reason they are thermophiles is because their proteins final folded state is favored at a higher temperature. So at that higher temperature, enzymes are more efficient (i.e. similar to the efficiency of enzymes in nonthermophilic organisms). This means, the primary structure of their amino acids... | [
"I like your response - its succinct and correct. I do have one small correction though: the organisms you were growing would actually be called \"psychrophilic\" (cold-loving). Thermophiles (heat-loving) are generally considered to be microbes that grow best above 45 to 50C, while hyperthermophiles (extreme(?)-hea... |
[
"What's keeping the cells in our bodies from aggregating into one giant cell."
] | [
false
] | I know that it is not favourable for a cell to do this since its volume will get too big for it to sustain itself. But is it not energetically favourable for such things (like bubbles) to aggregate into larger masses. What's keeping it from doing this? | [
"The ",
"glycocalyx",
" plays some part in this. Essentially, sugars and proteins in the cell membranes protrude out and carry charges with them. These can be organized in such a way to keep cells appropriately distanced from each other so that they don't fall apart or merge. ",
"There may be other factors, b... | [
"Short answer: at the microscopic level, it is energetically unfavorable for cells to merge together, and a distance between cells is generally maintained to prevent the theoretical low rate of accidental merging.",
"Longer answer: The cell membrane is composed of a lipid bilayer, where you have a negatively char... | [
"Intercellular structure. It is the ",
"\"part of the animal tissue that usually provides structural support to the animal cells in addition to performing various other important functions.\"",
" It's mostly made of polymers and fibers."
] |
[
"If the time dilation (w.r.t. a \"far off\" observer) approaches infinity as one approaches the event horizon of a black hole, how can anything ever fall into a black hole from an external observer's point of view?"
] | [
false
] | Let's say A is falling into a black hole, and B is a "far away" observer watching A fall into the black hole. As A gets closer to the singularity, A's clock will start to tick much slower than B's clock. As I understand it, this dilation approaches infinity as A approaches the event horizon. Doesn't this mean that the ... | [
"If the time dilation (w.r.t. a \"far off\" observer) approaches infinity as one approaches the event horizon of a black hole, how can anything ever fall into a black hole from an external observer's point of view? ",
"You're exactly right. Things crossing the event horizon seem to take forever from an outside po... | [
"I actually tried working this out a few years ago. Assuming the observer is a person who has a surface area ",
" and is a black body at some temperature ",
" (probably about 300 K) then you should be able to determine the average amount of time between photon emissions from the person. If you assume that there... | [
"I actually tried working this out a few years ago. Assuming the observer is a person who has a surface area ",
" and is a black body at some temperature ",
" (probably about 300 K) then you should be able to determine the average amount of time between photon emissions from the person. If you assume that there... |
[
"Can someone identify this infernal substance I found in my washing machine?"
] | [
false
] | null | [
"When I pushed the drum to the side",
"This was your big mistake. Normally we don't do this. LOL",
"Can someone help me identify this substance?",
"It's a substance technically known as \"grunge\".",
"IANA microbiologist, just a housewife. Washing machines tend to collect grunge in odd corners and nooks, it... | [
"The American Heritage Dictionary of the English Language says the definition of smelt is: ",
"\"smelt (smlt)\nv.\nA past tense and a past participle of smell.\" "
] | [
"The American Heritage Dictionary of the English Language says the definition of smelt is: ",
"\"smelt (smlt)\nv.\nA past tense and a past participle of smell.\" "
] |
[
"Would materials harvested from space and brought back to earth have any consequences at all from its weight accumulating on earth?"
] | [
false
] | Would there ever be any long term effects on earth after, say, harvesting tons and tons of metals, rock, etc. from space over time? Or is it just a drop in the bucket? | [
"Interesting that you use the metaphor of \"a drop in the bucket.\" How many drops would it take to equal 1 bucket? If we assume a bucket of 5 liters, and that each drop of water is 50 microliters, there are 100,000 drops in a bucket.",
"You mention tons and tons of metal, rock, etc. Let's say we one day harvest... | [
"To add to that, the mass of ",
" in the entire asteroid belt between Mars and Jupiter is ",
"estimated to be about 3*10",
" kg",
", or 3*10",
" metric tons, i.e. ~1/2000 the mass of the Earth. About half of that is in the four largest bodies (Ceres, Vesta, Pallas and Hygiea). ",
"On top of that, we p... | [
"(1/2000 = 0.0005 buckets)*100,000 drops/bucket = 50 drops. ",
"Although if you spread it out in an even layer over the Earth's surface, 3x10",
" metric tons/(4pi(6371000 m)",
" ) is 5,880 metric tons per square meter, which sure seems like a lot of rock to drop on everybody's heads. At an approximate rock ... |
[
"During a glacial period, when sea levels are dropping, would ocean salinity be significantly higher?"
] | [
false
] | Assuming my understanding of glaciation is correct. When sea water evaporates the salt is deposited. Because that water is lost to snow and ice, sea levels drop. That would seem to imply that ocean salinity should be higher given a reduced volume of water. If that's the case... | [
"The logic is sound, but we don’t yet have any solid geological evidence for this.",
"There are some narrative conjectures about fossilized microbes which potentially corroborates this; but most models for salinity levels are based on theory, not geology... as of yet! ",
"We simply need to find a medium which ... | [
"The average depth of the ocean is about 4000 metes. Where during the ice age it was 120m lower. if you assume all the salt remained in the ocean then it'd be about 3% saltier on average.",
"If all the glaciers melted 'internet says' rise would be 70 meters rise. So what maybe 1.5% less salty.",
"When sea water... | [
"Yes, salinity was apparently higher during the last ice age. It's difficult to measure salinity from long ago: it doesn't have many good \"proxies\" (persistent chemical consequences that can be measured today).",
"However, a group of scientists (Adkins, 2002) did measure the salinity of water trapped in deep o... |
[
"Are plants more efficient at collecting solar energy than our current solar panels? If so, how much, and would it be feasible to collect energy from these plants without killing them?"
] | [
false
] | I'm doing a research project for the NY College Board, and I wanted to do it on gaining energy from plants, tree's, etc. So, how much energy do plants typically take in, and could we harvest that energy without massacring the plants? | [
"http://www.fao.org/docrep/w7241e/w7241e05.htm#1.2.1",
"They have 3-6% efficiency which is rather low compared to current solar panels which have an efficiency of around 20%.",
"The normal way people harvest it is by growing biofuel plants and harvesting them and making them into ethanol.",
"http://www.gizmag... | [
"Important to remember plants are cheaper"
] | [
"Do you have a cite for that?"
] |
[
"How is it possible to change momentum of a physical object by reflecting a photon, versus absorbing it?"
] | [
false
] | As I understand it, a solar/light sail works because the sails reflect photons and glean a small bit of momentum from each one. But if the photon is reflected, it departs with the same speed (obviously) and energy (as defined by its wavelength). If there have been no energetic changes to the photon, where did the extr... | [
"But if the photon is reflected, it departs with the same speed (obviously) and energy (as defined by its wavelength).",
"This isn't quite true. As you said, it will obviously have the same speed as before, but the wavelength of the reflected photon will be somewhat longer. Consider a frame in which the object ha... | [
"The key point is that momentum has a direction as well as a magnitude. A photon with energy E carries momentum E/c. If you absorb that photon, you acquire its momentum as well. If you ",
" that photon, then the final photon has momentum -E/c, with a minus sign because it is going the other direction. To conserve... | [
"We're basically saying that because we reverse the photon's vector, we applied a \"force\" to it that first cancelled out all it's momentum, then added an equal and opposite one to it before sending it on it's way?",
"Yeah.",
"it still seems like we're cheating somehow, as we aren't actively adding energy!",
... |
[
"When you look in a mirror, are you seeing yourself at twice the distance you're standing from the mirror because the light has to go to the mirror and then back to you?"
] | [
false
] | null | [
"Yes because you are seeing a ",
"virtual image",
" which is equidistance from the mirror."
] | [
"Yes."
] | [
"Yes."
] |
[
"Why can't an electron's velocity and position be found at the same time (Heisenberg's Uncertainty Principle)?"
] | [
false
] | I get the concept of an electron cloud and probability of position based on that, and get that an electron behaves as a wave and particle, but can't seem to grasp the principle. Thanks | [
"Think of it this way, ",
"A sine wave has a very well defined wavelength (which is related to momentum), it repeats itself in an ordered reliable fashion, but you can't actually ask ",
" the sine wave is except that it's everywhere and fills the number line.",
"Contrast this to a peak, like a well localized... | [
"A sound wave can be narrowed down. Not to a point, but pretty small. If I clap, it's pretty clear what moment it happens. It's just that I can't clap at a certain pitch. Likewise, the position of an electron can be narrowed down, but then it has a huge uncertainty in momentum.",
"An electron is not a particle in... | [
"To be perfectly clear, the Heisenberg Uncertainty Principle is not a statement of our inability to measure both position and momentum. It is a fundamental property of quantum objects that their position and momentum cannot be simultaneously be certain. There is a great video explanation of this ",
"here",
". S... |
[
"How is it that compressed gas produces extremly cold condensation, and where does it get the energy to \"make\" the cold?"
] | [
false
] | [deleted] | [
"When you open the can to atmospheric pressure, the compressed gas does work (so-called ",
"Δ",
" work) on the rest of the atmosphere to move it out of the way. (Imagine an invisible boundary drawn around the gas, which expands outward until the pressures equalize. In reality, mixing occurs in conjunction, but ... | [
"You're right. This is however due to PΔV work rather than the gas laws. I failed to mention it because I did not realize how much work compressed CO2 used until I ran the numbers. As a quick estimate using the figure of 853 psi at room temperature from this site:",
"http://ask.metafilter.com/35292/Why-is-carbon-... | [
"An intuitive explanation of what \"force\" cools down the gas is entropy. While the gas is inside of the compressed chamber, its entropy is relatively low given that the area that it can be is quite small. When released, the gas becomes more entropic, as it can now move wherever. So the cooling, an endothermic pr... |
[
"Are male cows attracted to female cows with big udders?"
] | [
false
] | Along the lines of how human males are attracted to human female breasts because of several psychological factors - including that big boobs = more milk for offspring | [
"Well domestic cattle are within the genus Bos, most species in this genus, including the closest relatives of domestic cattle, have a mating system whereby one Bull mates with many cows and therefore only a lucky few Bulls get to mate at all. So it's not the Bulls doing the sexual selection, their instinctual aim ... | [
"Instead of looking for evo-psych answers, just realize that adult attraction to breasts is a social construct."
] | [
"Faulty assumption: Humans males aren't attracted to breasts because they're large; they're attracted to breasts because they're breasts.",
"From ",
"Wikipedia",
":",
"The writers of the study had initially speculated that the reason for this is due to endocrinology with larger breasts indicating higher lev... |
[
"How does sugar affect the transition from water to ice (and how does it change the structure of water ice)?"
] | [
false
] | In contrast to normal water ice (from water that you just put in the freezer), a watery substance (be that water, water with some lemon juice, coffee, milk, tea…) that has some significant amount of sugar added (for example 10% sugar, 90% water) will freeze in a different way. That ice you can easily eat with a spoon w... | [
"If you assume an ideal solution and low concentrations of solute, then the freezing point depression can be modeled using the following equation: ",
"ΔTF = Kf · b · i \n",
"where ΔTF is your temperature depression, Kf is your ",
"cryoscopic constant",
", b is the ",
"molality",
" of your solution, an... | [
"Before put in the freezer the water will be stirred (and even warmed up as necessary) until the sugar is, optically, gone. I don't expect that to mean a perfect distribution on a molecular level, but at least thee sugar isn't still floating around as big crystals. When you leave the resulting sugared water in the... | [
"If that is indeed the case, then what you are seeing is most likely a result of the speed at which you are freezing the water. Freezing it quickly will result in a significant amount of the sugar being trapped inside the normal crystal lattice as it forms, resulting in the different look, however if you froze the... |
[
"Why would space planes not be a suitable method of interplanetary travel in comparison to typical rocket designs?"
] | [
false
] | null | [
"Our main problem in space exploration is the cost of launching into orbit. It's in the order of several thousand US$ per kg.",
"So, first of all, consider how much fuel you need to achieve orbit. ",
"Here's a picture of a Space Shuttle on the launch pad",
". Note how the huge fuel tank is larger than the spa... | [
"All right. Spaceplanes ",
" be efficient as reusable launch vehicles. Jet engines are much more efficient than rockets because they can use outside air for most of the reaction mass. They're heavier for the same thrust, but a spaceplane flying horizontally needs much less thrust, because it can use the energy fo... | [
"The first reason I can think of is atmospheric density. Wings that would work on Mars would be too large on Earth. Wings that would work on Venus would be too small to work on Earth. Wings would not work at all on Mercury. Wings that work on Earth might work on Titan, but would probably be a bit too large. Po... |
[
"How do quark colours work?"
] | [
false
] | [deleted] | [
"Well so there's electric charge right, we have a charge, lets say +, and its anti charge -. Well there's another type of charge carried by quarks that we've called color because it comes in 3 types (and 3 more anti-types). Red Green Blue. Now for reasons I'm about to get into, they always balance to be 'neutral' s... | [
"Well so let's recall what a force \"is.\" F=dp/dt, Force is fundamentally a change in momentum. So the way color charged objects exchange momentum to stay bound together is by exchanging a gluon. So let's suppose I have a red quark and a blue quark (and a green quark but I'm forgetting about it at the moment). The... | [
"well neutron stars are something different. They're not quite dense enough for a quark gluon plasma, at least to the best of my knowledge. There are some hypothesized objects called \"quark stars\" that are just slightly more massive than neutron stars but not dense enough to be black holes. They're so massive tha... |
[
"Why don't more animals hibernate in the winter?"
] | [
false
] | I was watching a special on Yellowstone Park yesterday on Animal Planet and it was showing what these animals have to go through to survive the winter. I suppose it makes sense that only carnivores could really hibernate -- but why is it exclusive to bears (to my knowledge)? I know they are able to lower their heart ... | [
"It can be ",
"physiologically taxing to hibernate",
", it could potentially reduce opportunities to mate, and hibernating animals may be more vulnerable to predators. Therefor, it is probably advantageous to hibernate as little as possible, which for some animals is no hibernation at all.",
"Furthermore, hi... | [
"Correct, going into torpor is a costly trait. As a bear/squirrel/etc it only makes sense for you to go into torpor when the benefits of reducing your need for caloric intake is greater than the cost of pumping up your intake and living through torpor. "
] | [
"I would argue that there are many other animals that hibernate as listed ",
"here.",
" ",
"And I would argue that some bears, particularly black bears. Are not true carnivores. Black bears only consume about 5-10% of their calories as meat and the food source they use most to pump up their fat stores is the ... |
[
"Why do we differentiate between Brønsted–Lowry and Lewis acids/bases?"
] | [
false
] | Which theory is actually used when studying chemistry today? Why is one more useful than the other in different scenarios? The difference between the two theories seems so miniscule to me; why not just stick to one? | [
"They’re each useful in different situations - you use the one that is most appropriate. For example, when working with transition metal complexes, Lewis AB is particularly useful to explain bonding, but when working with hydrogen-donating acids in aqueous solution, you might want to think of things in terms of pro... | [
"Bronsted-Lowry says that basic compounds are proton/hydrogen ion acceptors, not OH- donors. That would be Arrhenius, no? "
] | [
"Bronsted-Lowry says that basic compounds are proton/hydrogen ion acceptors, not OH- donors. That would be Arrhenius, no? "
] |
[
"Once urine is in the bladder, is there any way for the body to recoup the water in it?"
] | [
false
] | [deleted] | [
"The bladder is lined by a type of skin called transitional epithelium. The function of this type of epithelium is to allow it to expand and contract without leaking. This is because that is what the bladder is intended to do. The transitional epithelial cells are connected together by tight junctions, which form a... | [
"You are, quiet literally, continuously making urine. Therefore, without a bladder, you would CONSTANTLY be leaking urine. I can see that as impractical from a hygienic aspect as well as a predator/prey aspect. The role of the kidneys is to mechanically filter the blood and reabsorb water and manage electrolyte hom... | [
"Has there ever been any speculation on the evolutionary purpose or medical benefit of a bladder versus just kind of leaking through and routing the kidneys straight out? Just to avoid the ability of predators to track?",
"You could easily see a purpose to a bladder if you could absorb clean water back, but sinc... |
[
"Simply: Does sleep (or lack of) accumulate?"
] | [
false
] | Is sleeping kind of an isolated event per nights rest, or does it all add up? Also, any tips on how to get more quality sleep? | [
"Ah, exciting area of research!",
"The first thing to say that 'sleep sessions' are not isolated events - they reflect an overall move of your body to achieve homeostasis (i.e. stability or balance). ",
"Does sleep deprivation lead to longer sleep times at the next session? Not significantly so, as far as I am ... | [
"Sleep is divided into 'stages', going from awake to stages 1, 2, 3, 4 and REM sleep (wiki article here). ",
"FYI, a number of years ago the American Academy of Sleep Medicine changed this. Sleep is now classified as 1, 2, 3 and REM (they merged 3 and 4). This is even noted in the link you sourced."
] | [
"Sleep is accumulative. Its called Sleep Debt. Try this, although its a bit long:\n",
"http://www.med.upenn.edu/uep/user_documents/dfd3.pdf"
] |
[
"A question for volcanologists: what is the difference between a Peléan and Plinian eruption?"
] | [
false
] | From my own research into the question, i understand that Peléan eruptions are characterized by the presence of pyroclastic flows, but don’t Plinian eruptions also produce pyroclastic flows as well? Does the height of the ash cloud or eruption column dictate how the eruption is classified? By this same token, what is t... | [
"Volcanic eruptions are categorized not so much by what they produce (plumes, pyroclastic flows, etc), but by what happens at the vent itself. Generally, characteristics of the magma (gas content, viscosity) affect what kind of eruption occurs, and the type of eruption is strongly but not uniquely related to the ha... | [
"The wikipedia article on ",
"types of volcanic eruptions",
" is a good place to start (and for example describes some of the differences between strombolian and vulcanian eruptions). A panelist like ",
"/u/orbitalpete",
" might be able to provide a lot more detail though."
] | [
"Thank you very much for this response, it really cleared things up, thank you"
] |
[
"When a photon is travelling towards the centre of a gravitational field will its velocity increase?"
] | [
false
] | Ok so I know, of course, the short answer is no but I don't know why. I know that nothing can exceed the speed of light so this must not happen. But I also know that gravitational fields affect light. For example light bends around the Sun and light cannot escape the gravitational pull of a black hole. But if a photon ... | [
"will its velocity increase?",
"\nDoes the photon's energy and frequency increase?",
"It depends on who is watching. Let's check out the Schwarzschild metric with only radial motion in mind, ",
"(ds)^2 = (1-R/r)(cdT)^2 - (dr)^2/(1-R/r) \nwhere R = Schwarzschild radius \n",
"We now introduce the lightlike... | [
"But you're not measuring the speed of light. You're measuring the slope of the angle it makes in a specific coordinate system. By that logic, I could travel faster than the speed of light by making the graduations on the x-axis really close together."
] | [
"I'm describing null geodesics which give me the trajectories of lightbeams. This isn't algebraic trickery, it is a coordinate system tied to a specific frame. Causality is preserved because all nonzero intervals are expressed in coordinate speeds less than the null trajectory. ",
"That same lightbeam will alway... |
[
"How soon after the Big Bang did stars begin to form?"
] | [
false
] | Additional question: were all of the carbon atoms and above in the Milky Way galaxy formed in the Milky Way galaxy? | [
"The first stars began to form about ",
"150 million years",
" after the Big Bang, during a period known as \"reionization.\" Prior to this period were the \"dark ages\" where the universe was fairly uniformly filled with neutral hydrogen; since there were basically no charged atoms during this period, photons... | [
"Because during the dark ages of the universe where it was filled uniformly with hydrogen, it was quite hot still, and there was plenty of energy available to do work.",
"Work is done through any of the four fundamental forces -- the electromagnetic, weak, strong, and gravitational interactions.",
"The strong f... | [
"were all of the carbon atoms and above in the Milky Way galaxy formed in the Milky Way galaxy?",
"No. The Milky Way has grown over time, using 2 different processes. Basically, during the primordial phase, galaxies were fed by flows of gas (\"cold flows\"). This intergalactic gas wasn't very rich in heavy elemen... |
[
"Why does driving a vehicle for an extended period of time make you feel physically tired?"
] | [
false
] | Assume that you have gotten a restful, full-night's sleep. And the driving is done during the day time when you're most alert. How come when you drive for a very long time (not necessarily far), you feel physically tired and/or get drowsy at the wheel, even though you're not doing anything really "physical." Does the r... | [
"The brain is a hugely metabollically active organ, with massive blood supplies and energetic appetites to match. When you drive, you concentrate for an extended period of time. Just like when you take a big test in school. The brain is constantly processing new information and making decisions regarding your drivi... | [
"Sounds like you've trained your brain not to use so much energy. Along with refueling, yeah, I totally believe you. "
] | [
"If you read my other post in this thread, you will see this isnt the case. I developed a long list of better driving habits, many of which are cognitive in nature."
] |
[
"Do planets orbit at a constant velocity?"
] | [
false
] | Google search is telling me 2 completely opposite things. On every video about orbits it always shows the orbiting body moving faster the closer it is to the thing it is orbiting. As well as this spacecraft often use a planets gravity to slingshot to their next destination, which again implies an increase in velocity. ... | [
"In a circular orbit the orbital velocity is constant. In an elliptic orbit it is not. The orbital velocity is highest at the periapsis and slowest at the apoapsis. In elliptical orbits the orbiting body trades some kinetic energy for potential energy and then back again. That's why its velocity changes. ",
"Eart... | [
"In a circular orbit the orbital velocity is constant.",
"The ",
" of orbital velocity, aka speed, is constant. Velocity, which is a vector quantity, obviously isn't – its direction changes constantly. Indeed as per Newton's laws, an orbiting object is affected by a non-zero net force and thus must be constantl... | [
"But if our planet is constantly accelerating and decelerating depending on its position in the orbit of the sun, wouldn't we feel it?",
"Apart from the fact that the acceleration is very small, like others described, you don't feel gravity, since it acts in the same way on all the atoms in your body. What you fe... |
[
"Did Mars have an atmosphere like Earths in the past?"
] | [
false
] | If it did what happened to it? If not is it just because we lucked out in that department? | [
"There are a few factors going on there. The atmosphere is held on the planet by gravity. Particles moving too fast escape into space. That happens on a regular basis, but on Earth, we have plate tectonics, which causes volcanic eruptions that replenish the atmosphere. But the larger the mass, the better able t... | [
"In a very general sense, Mars has about the same composition as Earth (very general sense). The entire Solar System condensed from a disc of material, and different zones in the disc had slightly different compositions. Over 99% of the mass of the solar system is in the Sun, and the rest of the Solar System has ... | [
"Nice answer, can I ask why the tectonic plates are unique to the earth. Is mars, as a planet, made out of different stuff when compared to our planet? "
] |
[
"If a Thermos flask maintains heat by blocking conduction/convection by means of a vacuum gap in its walls, does that mean sound is also unable to travel through the walls?"
] | [
false
] | I don't have a small enough speaker to do an 'experiment', but would a source of sound be inaudible to an outsider if placed in a closed Thermos flask? I suppose it depends on whether the vibrating atoms can bridge the gap, which in turn depends on the amplitude of the source -- but if the gap was big enough, then sure... | [
"It ",
" mean that sound cannot pass ",
" the walls; but I stress \"through\" here, because if you put a soundsource inside & a detector outside, you will still get much sound arriving at the detector, as the sound will be transmitted quite effectively ",
" the walls & ",
" to the other side. Heat is not co... | [
"If the vacuum were perfect, and went all the way around then it would block all sound. It doesn't depend so much on the amplitude of the source, no air means no sound.",
"",
"It's probably not a perfect vacuum. I don't know how much gas remains in a vacuum insulated thermos, but thinner gas will make the so... | [
"Buy cheap thermos flasks by the bulk on eBay.",
"Put a speaker inside and slap on a branding like \"soundlight\"",
"Make a Kickstarter video saying how this will revolutionize your music experience and set a ridiculous funding goal",
"Gullible idiots fund your project",
"Profit",
"Notes: ",
"-if you wa... |
[
"Why have developed countries been hit so much harder so far (in terms of infection/death toll figures)?"
] | [
false
] | Is it a data/testing issue? Or is it a real phenomenon, maybe to do with the flows of people and resources being more dynamic in these countries? I just don't understand, from a geographical perspective, how we've gotten to this point and Thailand, not a small population either, registered just 4 deaths today. I'm stil... | [
"In addition to other factors listed, people in developed countries are more likely to travel, both to other countries and amongst communities.",
"Note that the first US wave came in at West Coast cities with more business travel with China/Japan/South Korea: Seattle, San Francisco, and LA. Then came cities that ... | [
"This links into my hypothesis around flows no? Good call on the West/East, hadn't noted that."
] | [
"This is a complex topic.",
"Generally speaking, it's a combination of :",
"On this note, spikes in the number of deaths due to COVID-19 may not be noticed in countries with a relatively high mortality rate.",
"Broadly speaking, communities living in isolated clusters (which tend to have contacts only within ... |
[
"Why is Trisomy 21 such a common disorder?"
] | [
false
] | I've heard from a few places that Down's Syndrome (3 copies of the 21st chromosome aka trisomy 21) is one of the most common chromosomal disorders in the world. Is there a particular reason for this? Is chromosome 21 just particularly bad a separating correctly during meiosis? If this is the case, why is this so? Is it... | [
"It can occur with all chromosomes, but it typically means the baby (or the cell clump) dies quickly. Trisomy 21 is one of the rare cases with a reasonable probability to survive. XXX, XXY and XYY (an additional X or Y chromosome) are cases that often survive as well, often even without a diagnosis."
] | [
"I don't know numbers. ",
"Looks like 16 is the most common",
", but unless it is limited to some cells, it doesn't lead to a live human."
] | [
"So DS is no more common than other chromosomal mis-pairings, but it’s only “common” because it has a high prenatal survivability?"
] |
[
"What does a whitening toothpaste contain that is responsible for whitening teeth?"
] | [
false
] | null | [
"Hi dentist here. Usually some sort of abrasive particle. Different material depending on the toothpaste. But its not going to do a great deal for your teeth. It will only remove surface stains from coffee, wine etc. and could actually harm your teeth long term. To actually whiten teeth you would need actual bleach... | [
"Lower concentrations (around 6%) are available over the counter (whitening trays/strips). Higher concentrations (like 35%) can damage your gums if applied incorrectly or for too long a duration (or your stomach if swallowed), so allowing any old Joe to buy and use that would expose a company to too much liability.... | [
"Curious, why is something like that only available from a professional?"
] |
[
"Is there any way to increase the number of dreams I have?"
] | [
false
] | I find it really annoying when a bunch of my friends can talk about the awesome dreams they've had, and most of the time I didn't dream at all, or it was so boring there was no point in retelling it- and even those are kinda rare. Would it be possible to increase the amount of dreams I have, and how? | [
"Start taking more naps."
] | [
"Keep a dream diary. I can only speak for myself but it worked wonders for my dream recall."
] | [
"It's extremely unlikely that you just don't dream(biologically, that's like someone telling you that they don't need to eat). Chances are you're just not remembering the dreams.",
"One thing you could try is a device or program like that wakes you up during a REM phase in your sleep cycle, since this tends to he... |
[
"Why do whales die when they're beached too long? What is it that kills them?"
] | [
false
] | I have always wondered this. Thank you for your responses, everyone! | [
"It's not dehydration or starvation, which would take a long time, but suffocation. Whales are normally supported on all sides by water, which means that they don't have to support their own weight against gravity. When they are beached, the weight of the parts of their bodies that are above their lungs is pushing ... | [
"Nope the Romans would get bored of waiting and come break your limbs so you can't pull yourself up to breath."
] | [
"So if you're completely ripped you can survive crucifixion longer?"
] |
[
"Laser + Colored Water?"
] | [
false
] | What would happen if I pointed a high powered laser through a clear container of colored liquid? | [
"It depends on the wavelength of the laser light and the absorption spectrum of the liquid. Laser light is usually a very narrow range of wavelengths. If the liquid absorbs that wavelength, no light will pass through. Otherwise all the light should pass through.",
"In practice I imagine there would be effects fro... | [
"The light will be absorbed in accordance to Beer's Law. The exact amount of light that gets through depends on the concentration of dye, the absorption cross-section of the dye at the laser wavelength, and the path length through the liquid."
] | [
"I actually did a science fair project on this last year. While our results weren't completely clear, they did suggest that the amount of diffraction (compared to the control, a container of clear water) was inversely proportional to the wavelength of light. In other words, redder colors diffracted the laser light ... |
[
"Where on earth have humans been living the longest continually?"
] | [
false
] | Listening to a podcast about ancient Assyria got me thinking: What is the place on earth where humans have been settled the longest continuously? You always hear about the Fertile Crescent being the location of the earliest civilizations, and people still live there, but what about South America or Africa? Are any of t... | [
"Given that we evolved there, probably Africa. ",
"Your question would benefit from defining what you mean by \"humans\" and \"settled\". I would tend to include all members of our genus (homo). If you mean humans that built permanent, surviving settlements, that would probably restrict the answer to modern human... | [
"Anatomically modern humans have been around for 200,000 years, the majority of this was spent in africa. We didn't leave Africa til 100k years ago at the earliest. And until about 10k years ago, agriculture and \"civilization\" didn't exist. Before that humans were small bands of hunter gatherers in very sparse po... | [
"It's gonna depend on how small of a \"where\" you're looking for. If you're happy with a continent, Africa has had people as long as there's been people, if you're looking for a space the size of a building, perhaps a hospital or casino somewhere has had people in it continuously for a few decades"
] |
[
"Has distributed computing projects such as folding@home and BOINC's rosetta actually produced real results?"
] | [
false
] | I thought would be the perfect place for this discussion as a part of "doing science" is investigating conclusions and building research models. One of the most successful, as we're told, has been the distributed computing effort. I'd like to know what has distributed computing actually achieved not just for the two pr... | [
"Research papers from Folding@home",
"."
] | [
"Sort of distributed computing: ",
"http://games.yahoo.com/blogs/plugged-in/online-gamers-crack-aids-enzyme-puzzle-161920724.html",
"Online gamers have achieved a feat beyond the realm of Second Life or Dungeons and Dragons: they have deciphered the structure of an enzyme of an AIDS-like virus that had thwarted... | [
"AIDS-like virus",
"Ouch."
] |
[
"Is it possible to make a laser that produces white light?"
] | [
false
] | [deleted] | [
"A single laser does not produce white light. If the peak power of that laser is high enough, it can be focused through a medium (sapphire is generally used) and the nonlinear effects of that medium will cause an extreme line broadening known as ",
"Supercontinuum generation",
". This effect is commonly used ... | [
"Lasers work by isolating a single wave length of light, white light is only observed with a combination of wavelengths. So you can never have a white laser but you can create white laser light by combining multiple lasers."
] | [
"What about pink?"
] |
[
"When deep sea fish die, what happens to them?"
] | [
false
] | Two questions really: A) Do they float like other fish do and B) If so, what happens to them on the way up when the pressure is much lower than the pressure of their natural depths? | [
"Once they hit the sea floor, they become miniature habitats for microorganisms and plankton. Look up \"whale fall\" to see what happens when a whale dies and sinks to the sea floor."
] | [
"On the topic of whale falls, ",
"here",
" is a charming and enchanting depiction thereof."
] | [
"Here's a ",
"video",
" I did a quick search regarding whale fall :)"
] |
[
"what is the minimum number of output pins you need for an n key keypad?"
] | [
false
] | [deleted] | [
"Assuming no active keyboard controller to turn it into serial data, and each line carries only binary information, and you don't mind coming up with fairly complex wiring...",
"You can get away with ceil(log2(keys)) wires."
] | [
"ceil(log2(keys+1)), if you want to be able to say you're not pressing any key."
] | [
"Ah, good call! Thank you for the correction. :)"
] |
[
"How did Einstein insert a cosmological constant into his general theory of relativity?"
] | [
false
] | [deleted] | [
"Einstein's equations were a long time in the making, but once he got to the right place, he knew the basic ingredients: he needed an equation which related a rank-2 curvature tensor (i.e., a 4x4 matrix describing the curvature of spacetime) to the stress-energy tensor, another rank-2 tensor describing the distribu... | [
"Einstein's equation, with the constant",
"The last term on the left hand side is the cosmological constant term. If you set lambda=0, you get the regular Einstein equation."
] | [
"...did you just report my answer to the mods?"
] |
[
"Will the length of tubing have a significant effect on how much oxygen a patient receives?"
] | [
false
] | One of the things I frequently hear is that a patient on 2 liters per minute (lpm) home oxygen with a fifty foot extension tube is likely only receiving half a liter by the end. I understand that fluid pressures are effected by the resistance of the hose/tube they travel through but my knee jerk reaction is that oxygen... | [
"Depends on the supply system:",
"The throughput of a viscous liquid through a tube depends on the pressure difference at both ends, the length of the tube, the radius of the tube and the viscosoty.",
"http://en.wikipedia.org/wiki/Hagen%E2%80%93Poiseuille_equation#Poiseuille.27s_equation_for_compressible_fluids... | [
"Thank you."
] | [
"the resistance of any material flowing through a pipe (gas solid or liquid) is compounded by the decrease in diameter or an increase in the length of the pipe "
] |
[
"Do they replace warheads in nukes after a certain time?"
] | [
false
] | Do nuclear core warheads expire? If there's a nuke war, will our nukes all fail due to age? Theres tons of silos on earth. How do they all keep maintained? | [
"The DOE publishes an annual Stockpile Stewardship Management Plan. For a boring government report it’s actually pretty interesting.",
"https://www.energy.gov/nnsa/articles/stockpile-stewardship-and-management-plan-ssmp"
] | [
"Also, for the overview from the same source: ",
"https://www.energy.gov/nnsa/maintaining-stockpile",
"To OP's question: nuclear weapons are ",
" maintained with swaps and replacements happening all the time. Eventually, when even strict maintenance can no longer sustain the design performance of a weapon, as... | [
"The main thing that needs to be replaced is tritium, which has a half life 12.355 years. This means tritium needs to be replaced every 7 to 8 years or so, otherwise the weapons will \"fizzle\". Tritium is expensive to produce, the US operated a number of heavy water reactors specifically built for the purpose duri... |
[
"How big is the average rock in Saturns rings? And how far apart are they from each other?"
] | [
false
] | Couldn't find the answer in google so might as well try here. | [
"Most of the rings is just dust. But there are bigger rocks as well. Some can be as big as a house and very few even larger ones. Even a moon can be found inside the rings, causing waves in his surroundings. ",
"picture",
".",
"\nAnother interesting fact is the thickness of the rings. The rings are only a few... | [
"That moon image really brings it into perspective just how enormous Saturn is."
] | [
"Totally. Also, look at that gap between the rings and how straight it seems. Yet, you know that's just once small part of a huge circle."
] |
[
"Could I use the delay with which forces propagate through matter to 'create' volume?"
] | [
false
] | So, say you had a tube in space that was exactly the diameter of a tennis ball. It is, say, 500,000,000 tennis ball lengths, exactly, and has 500,000,000 tennis balls in it. I push five tennis balls in one end. Now, since this tube is just so long, there's a delay before 5 tennis balls come out the other end. Let's say... | [
"Assume the tennis balls don't squish",
"This is where the problem arises. ",
"Tennis balls do squish",
"In fact, if they were incompressible, there would be no time delay between when you push the first one and the last one comes out the tube."
] | [
"Yes, and that's why it's not physical to speak of incompressible objects."
] | [
"It would be infinitely fast. Materials for which the speed of sound is the speed of light are still compressible (except don`t exist)."
] |
[
"Why do we use optical telescopes for space exploration?"
] | [
false
] | I know we have radio telescopes observing the universe on various wavelengths, but why do we also have optical telescopes? It seems to me that a radio telescope (in my understanding a giant array of satellite dishes) would be much easier to manufacture than the lenses/mirrors involved in an optical telescope. So why ha... | [
"You see different things in different parts of the electromagnetic spectrum (see ",
"Multiwavelength Milky Way",
"). Different sources will emit differently because of different physics, thus we need telescopes across the spectrum to study these phenomena.",
"Also, you cannot calibrate a radio telescope to s... | [
"OK, maybe I phrased my question poorly. Here's another try: Why can't a radio telescope function on visible light wavelengths? Is there a physical limitation? Or an engineering limitation?",
"It seems to me, as a lay person in regards to physics (software engineer), that we're talking about electromagnetic waves... | [
"Glass is just there to protect the mirror. The actual mirror is usually made out of polished metal. After all, it's much easier to polish a 5 m",
" piece of metal than it is to make a high quality 5 m",
" mesh of nanowires."
] |
[
"Is there anything wrong with heating food up in the microwave?"
] | [
false
] | My friend's family constantly gives me crap for heating food up in the microwave. They tell me the radiation will give me cancer because it messes with the atoms of the food. I highly doubt this and would like a real answer from someone who knows a bit more about the subject. I already know most frozen food isn't initi... | [
"They tell me the radiation will give me cancer because it messes with the atoms of the food.",
"Nope. Microwave radiation isn't nearly powerful enough to disturb the nucleus of an atom.",
"Microwaves work by basically slapping around water molecules, and heating them up.",
"People often confuse radiation (a... | [
"As for advice in actually convincing them of this, you really can't take the approach of \"I know everything and you're all wrong\". What you need to do is learn everything you can about microwaves, and then ask ",
" questions about how they work. How does the magnetron make ionizing radiation? What is ionizing ... | [
"Thats the plan! A few of these post will help a lot in my case."
] |
[
"Will radon gas ever stop being generated and leaking to the surface at some point in the future?"
] | [
false
] | So radon gas leaks from the soil beneath us, but will it ever stop being generated or at least decrease enough to that it's not a threat to public health at all? If so, how long would that take? | [
"In short, no. The more common isotopes of radon are produced as part of decay chains associated with ",
"U",
", ",
"U",
", and ",
"Th",
" with the most stable isotope of radon (",
"Rn) being part of the ",
"U chain. The half lives of the parent isotopes are long (",
"U - 4.47 billion years, ",
... | [
"I would say \"no\" is still the correct answer denpendig on the time scale you look at. The half lives of the parent isotopes are in the order of the live time of the sun. Since op asks about ",
"threat to public health",
"this is the time scale you have to look at."
] | [
"The answer is yes if your time scale goes past the death of the Sun. So, it's no."
] |
[
"Why do women react to temperatures differently than men?"
] | [
false
] | [deleted] | [
"There is real evidence behind this! Female mammals often display a temperature preference a few degrees higher than their male counterparts. We talked about it in one of the classes I took a year ago. I found the slides, which have some neat data on them regarding mice temperature preferences. I uploaded them ... | [
"My wife always complains about being cold, be she is like a blast furnace in bed. It may be a evolutionary adaptation, trading body heat to help keep offspring warm."
] | [
"Why is there an incredible amount of down voting on this post?"
] |
[
"Would you experience gravity inside a hollow planet?"
] | [
false
] | So let's say you have a planet with a solid core, and in the center you create a chamber (like a big empty ball). If you would be in the chamber is it just like pressure (like being deep in the ocean)? And also if you change what the planet is made of to something with 10 times the mass. And at the same time you make t... | [
"No, the net gravitational force on a body within a hollow sphere is zero. This is the ",
"shell theorem",
", and it's the theoretical justification for using point masses instead of planets to simplify, say, orbital mechanics calculations.",
"For the pressure question, if you fill the chamber with a gas, say... | [
"Yup. What is physics if not simplifications? :P"
] | [
"Yeah, it would be as if all the mass were in the center."
] |
[
"Why can hot water do so many things that cold water can't?"
] | [
false
] | null | [
"Basically all of those things involve dissolving something in water.",
"As the temperature of the water increases, solubility of the thing you are trying to dissolve (solute) also increases."
] | [
"Not many people seem to realise this, but an additional reason is that the dielectric constant of water goes down rapidly with increasing temperature, which means that boiling water is about 40% less polar than room-temperature water. Since most fats, oils, and greases are also non-polar, this increases their solu... | [
"I would beg to argue this. Part of the function of soap is to form micelles around hydrophobic entities to contain and make them soluble in water. Temperature has at least some effect on the ability of those micelles to form, and definitely on their solubility in water. I know it takes me much more cold water to r... |
[
"How far out into space have we sent something physical and had it return?"
] | [
false
] | For example if our solar system was USA and earth was DC have we passed the beltway, Manassas, Chicago or are we still one foot in the door of the white house? | [
"Things you learn from Kerbal Space Program: Traveling in Space is 90% about lifting fuel into Orbit."
] | [
"Here is one data point: The Japanese Hayabusa mission was 290 million km from Earth when it landed on asteroid Itokawa, from which it later returned. See ",
"http://news.bbc.co.uk/2/hi/science/nature/4463254.stm",
" and ",
"http://www.bbc.co.uk/news/10285973"
] | [
"We haven't really improved on our speed since the 1960s. Space travel isn't like what it is in the movies. Generally you wait for proper alignment and do an engine burn to transfer orbits. There are more vs. less energy favorable orbital transfers. ",
"It comes down to how much money do you want to spend launchi... |
[
"What do we know about our sun's predecessor star? That is to say, the star whose nova debris our solar system accreted from?"
] | [
false
] | Or is it not that simple somehow? Was there more than one such nova? | [
"It is not that simple. The solar system formed out of a molecular cloud containing contributions from many predecessor stars (supernovae, giant stars, planetary nebula, etc.). All we can say with certainty is that a ",
"supernova contributed material to the cloud just after (1 million years) it collapsed to form... | [
"...and what blows me away is that not only are the molecules that compose my body the same ones that have been part of ",
" of human (and other) bodies, but if life is common in the universe, then these molecules that make up yours and my bodies may also have been molecules in the bodies of ",
" organisms in o... | [
"We are probably the mixture of hundreds, if not thousands, of ",
"Population III and Population II stars",
"."
] |
[
"Is wearing headsets bad for health?"
] | [
false
] | null | [
"As long as the headphones are not making sounds loud enough to damage your hearing, no. "
] | [
"What about the pressure from the headphone band at the top of my head?"
] | [
"Are you wearing your hair off? If not, don't worry about it. People have worn hats forever without ill effect. "
] |
[
"Is it likely that any of the Mass Extinction Events in Earth's history were caused by nearby Supernovae or Gamma Ray Bursts?"
] | [
false
] | null | [
"It is thought that a gamma-ray burst may have contributed to the ",
"Ordovician-Silurian extinction event",
" 440 million years ago but I think this is just based on circumstantial evidence. "
] | [
"Yup."
] | [
"Just to clarify, the Wikipedia article you linked to states that T. Pyx is of no danger. Did you have a different reference which contradicts this?"
] |
[
"What would happen if you \"carbonated\" soda with helium instead of carbon dioxide?"
] | [
false
] | Yes, I'm daydreaming about Willy Wonka and the Chocolate Factory. I need to know. | [
"At 5C, about refrigerator temperature, CO2 has a solubility in water of around 3g/L of gas, giving around 1.5L of gas per liter of carbonated water at room temperature.",
"By comparison, at 5C, helium only has a solubility of 0.00165g/L, but since helium is so much lighter than carbon dioxide, you'll still get c... | [
"I was thinking more along the lines of gastric rupture - the human stomach tops out at 4L or so if I remember right."
] | [
"Super long, super loud, high-pitched belching?"
] |
[
"How far could Felix Baumgartner have let the balloon rise before gravity would not have pulled him back down?"
] | [
false
] | null | [
"You have to remember that there's gravity everywhere in space. Mr. Baumgartner would have to be moving at very high speeds (escape velocity, I think) in order not be influenced by Earth's gravity. Even the International Space Station is free-falling towards Earth; it's just moving forward fast enough that it's \... | [
"Gravity would have pulled him back regardless of the height he got to. And I don't mean to say that a balloon cannot rise high enough but that there is no such height at which he would not have fallen back. "
] | [
"Not sure why you're being down voted. You're mostly correct. I believe they said 125k feet was their expected ceiling. He rapidly ascended to 128k+ feet."
] |
[
"Why are we told to cover our mouth with a wet cloth when there's a lot of smoke?"
] | [
false
] | [deleted] | [
"The cloth will keep ash out of your lungs while you breathe. ",
"The wet cloth will also slightly cool the incoming air, but I don't know if that effect will be biologically significant.",
"I have been unable to find any evidence on google scholar, possibly due to poor google-fu, specifically related to wet f... | [
"The wetness of the cloth also helps to filter out ash, take the example of if you had a pile of ash on a table. if you touched it with you finger while dry not a lot of ash would stick to it. Now if you wet your finger and touch the ash a lot more will be stuck onto your finger.",
"Apply this to the clothe while... | [
"Even if there's a biologically significant difference, it may be completely counteracted by the time spent wetting a cloth. A raging fire grows worse with time in most cases, so you may be in a worse situation by waiting."
] |
[
"Could you manually melt the ice caps?"
] | [
false
] | null | [
"Hi Packmanjones thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the fo... | [
"Earth sciences"
] | [
"Flair has to be manually assigned after you submit your post by yourself"
] |
[
"What’s the difference between men’s and women’s multivitamins?"
] | [
false
] | null | [
"Their effectiveness is debatable but they purport to target the specific needs of each gender i.e. iron and calcium for women (anaemia and osteoporosis); zinc and selenium for men (testosterone production and sperm production) etc etc. "
] | [
"\"Effectiveness is debatable\" usually means no credible research has found anything, but obviously-biased sources have."
] | [
"Their effectiveness is debatable",
"I would think the efficacy of multivitamins would be so well researched by now. Scientifically, how is there not a generally accepted view of their effectiveness? "
] |
[
"Why do different engines of the same size have different power outputs?"
] | [
false
] | null | [
"There are a lot of things that specify the output of an engine. The displacement is one of them (maybe the most important) but there are really a ton more. One very important thing that can really change the whole behavior of the engine is the setup of the camshaft(s). Moreover if the engine has a turbocharger or ... | [
"There are many many reasons, but the biggest is that fuel (fully) burned per unit time determines output power. Displacement is how much air/fuel the cylinder can hold (time is not a factor). And fuel burned is limited by oxygen in the cylinder (and thus air). Air however is compressible, in a naturally aspirated ... | [
"A big overall consideration, out of all of this, is that there is only so much energy you can extract from a heat engine - 50% efficiency. While many engines are near the 25 or 30% efficiency, there is only so much you can do with a gallon of gas. You can either move a whole lot of weight [trucks], or you can go... |
[
"Recently, a group of astronomers discovered the universe's first molecule in a dying star, the helium hydrate ion (HeH+). How could they tell it was the universe's first molecule?"
] | [
false
] | [deleted] | [
"What makes HeH+ more likely than H2?"
] | [
"The elements that resulted from the Big Bang were Hydrogen, about 25% Helium and less than 0.01% Lithium and Beryllium. Given those ratios its pretty safe to assume that HeH+ is going to be one of the first molecules because there aren't many other choices."
] | [
"Helium has a higher ionization energy then H. Therefore, at t some ttime efore recombination (~380,000 years after BB), as the universe cooled, neutral He formed in the presence of ionized H (H",
" These combined to form HeH+. A molecular orbital diagram indicates this to be stable molecule with a bond order ... |
[
"If I'm incredibly drunk and a mosquito bites me, will my high BAC effect the insect in any way? Can insects get \"drunk?\""
] | [
false
] | null | [
"When nectar ferments on the flower, it turns into alcohol. Bees that visit said flower will absorbe some of the alcohol thorough their bodies. This will cause them to get drunk. The interesting part is that when they make it back to the hive, the other bees know that they are drunk and will block the drunk bee fro... | [
"Not that I don't believe you but source?"
] | [
"The mosquitos probably won't be getting drunk from drinking your blood, it just doesn't have enough alcohol in it (0.3% alcohol by volume in your blood will leave you ",
"unconscious or dying",
", actual beer would have 3% or more, which 10x more). But ",
"bees can totally get drunk",
". "
] |
[
"Mathematical fate; Possible?"
] | [
false
] | Let's say you had a bouncy ball and a cardboard box. Once you threw the ball into the box, is the trajectory of the ball not predetermined? Assuming a finite number of particles in the universe after the big bang, after gravity and strong nuclear force split from this mass as laws, would the trajectory of each particle... | [
"In terms of Newtonian physics you're pretty much right yes, if you have enough information about a system you can predict where it will end up, though for a complex system you would need a vast amount of information. Quantum physics buggers that up though, by throwing various uncertainties and random variables and... | [
"Chaotic systems are still deterministic, it's just that very small variations in system inputs can result in wildly different behaviours, which make predicting long-term behaviour hard ",
". If you had complete information and enough computational power, the long-term behaviour could be predicted for any input."... | [
"You are thinking of ",
"determinism",
".",
"It is probably better suited to a philosophy subreddit, since the required principles (complete information on a system with zero error and obscene computing power) do not exist in science.",
"That said, I'll try to answer your question in brief. ",
"Within cla... |
[
"Can someone explain why Quantum Entanglement is \"bizarre?\" (What makes it different from macroscopic conserved systems?)"
] | [
false
] | I am completely confused about why it should come as a surprise so I must misunderstand something about it. From what I understand, Quantum Entanglement is two particles that in some way originated such that the total conserved value of a property in a system is known but what is not know is the constituent contributi... | [
"Because entanglement is just ",
". It's commonly explained this way for some weird reason, but it's completely wrong and misses the point.",
"For example, one often mentions the entangled state",
"|0>|1> + |1>|0>",
"This is the superposition of a state with particle A with spin down and particle B with s... | [
"I genuinely hate when people bring spin conservation into the discussion of entanglement. This is done by phycisists who should know better. It's not that I'm disagreeing with spin conservation. It's that it's a complete red herring. "
] | [
"I think it happens a lot when considering the reality of performing an experiment. It is pretty typical to have a spin 0 particle decay into two particles with spin. In this case, you actually know the spin wavefunction. It is generally difficult to create an arbitrary wavefunction, so this example is used a lo... |
[
"All My Professors says X-Ray Crystallography takes a lifetime devotion...why?"
] | [
false
] | From Junior year of high school all the way through to now, every sciences teacher that had mentioned X-ray crystallography has said that in order to be able to perform and interpret them you must dedicate your life to that subject. I understand how the DNA, proteins, or other biomolecules refract the x-rays, but how d... | [
"The difficult aspect of protein (and other macromolecular) crystallography is getting a crystal. If you have a certain protein, there is no guarantee that it will crystallize. Usually, you have to screen the protein against a lot of conditions (different pHs, solvents, etc.) to find one with crystals. When any giv... | [
"but how do they get a 3D structure from one square picture?",
"Let's take a step back for a moment and consider the double slit experiment. When light passes through a slit, it is ",
"racted (not ",
"fract - that's something else entirely). The pattern on the screen after the light passes through the slit ... | [
"So the difficulty rises from interpreting the diffraction and their intensity to determine this 3D structure. So by determing where the slits are you can put them into an equation and that equation will give you a skeleton"
] |
[
"How does the brain work to not 'cascade' through every connection when one is triggered?"
] | [
false
] | null | [
"Most of the connections in your brain are actually inhibitory, not excitatory. "
] | [
"Understood, but I guess the broader question is why? How or why did our brains develop in this manner?"
] | [
"Even the most elementary organisms have inhibitory circuits. It's nothing special about it being a human brain. It allows for much more complicated patterns of activity and prevents things like all of your cells being active all the time."
] |
[
"What specifically allows ants to lift such huge masses compared to their own mass as compared to humans and other large animals."
] | [
false
] | Obviously the exoskeleton has something to do with it but that can't be the whole story! | [
"The answer is more physics-based than anatomy-based.",
"Basically, their great relative strength is because of their small size.",
"Strength of a muscle is based on its surface area, which, being a two-dimensional measurement, decreases by a factor of 2 (x",
"Size of an muscle is based on its volume, which, ... | [
"Both: their small size affects how much weight they can lift as well as how much they can hold without \"breaking\" relative to their mass. ",
"It makes sense that a muscle with greater surface area could withstand greater force, as well as exert it on another object.",
"(Please correct me if I'm wrong. I'm ba... | [
"What I heard is that the power of a muscle depends on their section's area. Surface area is a bit of a confusing term I think.",
"Think about the strength of a metal cable. Its tensile strength depends on the thickness of the cable."
] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.