title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"how do we determine the size of the entire (not just observable) universe?"
] | [
false
] | this question was inspired by recent submission to reddit. they list the estimated size of the entire universe to be about 900 Yottameters. How did they come to this number? my best guess is that is has something to do with rate of expansion of the universe. but how can anyone be certain of such a thing? it seems that even throwing out a ballpark number is useless when dealing with such questions. any help? | [
"I think that submission is wrong. What it claims is the entire universe at 93 billion light years diameter is actually the observable universe. It claims the observable universe is 14 billion light years, however due to the expansion of space the observable universe is actually around 93 billion light years. ",
... | [
"The paper that produced the ~250 Hubble sphere lower bound can be found ",
"here",
". That paper also shows that a flat universe is more likely than a curved one to have produced the observed data."
] | [
"In an infinite universe, every finite subset is a small scale. ;)",
"But yeah, I understand that in human terms these are enormous scales."
] |
[
"Do trans people's brains actually resemble the brains of their experienced gender? Where does transexuality come from?"
] | [
false
] | null | [
"I posted ",
"this article",
" that was published late last year in a similar thread yesterday. It's a case report of a male with psychosis-induced gender dysphoria. They treated with antipsychotics and resolved the GD.",
"The full paper is fascinating. The man was given constant brain scans during treatment.... | [
"No. In this case, an individual went to a clinic to get sexual reassignment surgery. They do a full psychological workup beforehand to make sure there are no mental illnesses present that may be altering their decision to transition. They discovered that they had LSD-induced psychosis which was causing the GD, so ... | [
"The most concise answer is this: There is some compelling evidence that the brains of trans people \"resemble\" the sex that they identify with, and it's the leading theory for why transexuality exists, but absolutely more research needs to be done. I'm posting some relevant links below:",
"Science journalism:"... |
[
"If gravity acts upon objects with mass, and light is made of photons (no mass), how can gravity 'bend' light?"
] | [
false
] | In the example of a black hole, the central mass, or object, exerts so much gravity that it has an escape velocity > c. However, if a photon has no mass, how can gravity affect it? Thanks, askscience! | [
"In general relativity, gravitational mass distorts spacetime. Near to very large masses, this distortion gets large. The light is still travelling in a straight line in its local spacetime, it's just that a straight line near to a large mass looks bent from far away. It's like lines of ",
" longitude: they're al... | [
"In the future you should consult the ",
"FAQ",
" for very commonly asked questions like this one:",
"If light has no mass, how does gravity affect it?",
"Conversely, you should also do a quick search to find ",
"other past threads",
"."
] | [
"At least in special relativity, there is an ability to calculate invariants, quantities that are fixed across all reference frames. One that comes to mind that would seem to ignore the warping of spacetime is the invariant mass, or the mass of a particle at rest. As for GR invariants (which is really what somethin... |
[
"Why do tortoises live so long compared to other organisms?"
] | [
false
] | null | [
"Certain tortoises have negligible senescence...",
"http://en.wikipedia.org/wiki/Negligible_senescence"
] | [
"Many the same predators that attack water buffalo, zebra, or gazelle, had no problem with going after a human. "
] | [
"But humans also lack predators.But once a human reaches old age, he is more susceptible to diseases.Why are tortoises more immune to these diseases?"
] |
[
"Why is the skin on your lip different from the rest of your body?"
] | [
false
] | null | [
"For the following explanation please have this picture handy: ",
"http://upload.wikimedia.org/wikipedia/commons/2/27/Skin.png",
"It's not actually that different. The skin of the lips, from outside of the mouth to the inside of your mouth, has 3 parts: the pars cutanea (the edge of your lip from outside), the ... | [
"Someone also posted on one of the subreddits that the skin on the inside of your mouth is the same as a vagina. Don't quote me yet, I'll hopefully be back with an edit."
] | [
"I don't have an online source for this, but I remember seeing on the Discovery Channel (take that for what it's worth) that lips evolved at the same time that humans began walking upright and the vagina move forward on the anatomy. This had an effect of you couldn't really see a vagina just from walking behind som... |
[
"As there are colours that cannot be distinguished by the colorblind, are there things that only colorblind can see?"
] | [
false
] | I hope the question is not too dumb. I just had an idea for a b-day gift for a friend and we're always spoiling him (in a friendly way) cause he's colorblind. I wanted to know whether there are colours that colorblind can distinguish better, so that only he would see an image with those colours... Did I make myself clear? I'm sorry if the question's too dumb. Have a great day! :D | [
"It's possibly to make an image that's easier for a colorblind person to see. We had one in a lab I taught on genetics. Basically, you have a scattering of red and green dots that look the same color to someone with red-green colorblindness but very different to someone without. Then you have a slightly darker s... | [
" there is a set of colours that would appear to be ",
" to him than the average person... It would depend on exactly what kind of colorblindness he has (there's ",
"quite a few types",
"). Obligatory not-an-expert but I think it's impossible to make an image that would only appear to colorblind people."
] | [
"Yes-- well, patterns more than colors-- such as certain types of ",
"camouflage",
", which is why in the past ",
"armed forces",
" have actually recruited color-blind men."
] |
[
"Why do our bodies urge us to scratch when in virtually all cases it makes the problem worse?"
] | [
false
] | Good examples being eczema, athletes foot, sun burn, etc | [
"This guy blogged about that. ",
"http://doctorandy.blogspot.com/2006/05/why-we-scratch.html",
"There's a link in the article to a scientific paper."
] | [
"I find it contrary to the usual adaptive aspects of evolution.",
"That's the thing though; society can move ",
" faster than evolution can ever keep up with. ",
"Technological progress and the storing and generational transmitting of knowledge, far, far outclasses evolution in providing an organism some fitn... | [
"I hope I didn't come across as asserting that, I know our minds and technology far exceed the speed of evolution (I.E wisdom teeth). However, things that cause fits of scratching would seem to be omniscient throughout the history of homosapiens, making it seem that evolution would have \"made it clear\" to not scr... |
[
"Why makes Endometriosis so hard to diagnose?"
] | [
false
] | According to Wikipedia, “Women suffering from endometriosis see an average of seven physicians before receiving a correct diagnosis, with an average delay of 6.7 years between the onset of symptoms and surgically-obtained biopsies, the gold standard for diagnosing the condition. This average delay places endometriosis at the extreme end of diagnostic inefficiency.” What makes Endometriosis so hard to diagnose? Is it purely social factors (“periods are supposed to hurt a little, get over it” etc.) or are there other factors involved that complicate diagnosis? | [
"I wrote my thesis partially on this topic. I’m on my phone so don’t have source list handy but can update later if requested.",
"It’s due to a few compounding factors. Chronologically, one of the first delays is that the women themselves don’t know that their periods are particularly bad. A significant number of... | [
"As someone who is just finishing her PhD on endometriosis, I want to second everything you’ve written and also add that medical sexism has made it so that endometriosis has been misdiagnosed and mistreated for centuries.",
"Endometriosis is commonly misunderstood as a disease of the uterus, but it is actually a ... | [
"Did my honours on this and in the process of PhD. It has a huge variety of factors.",
"Firstly, the menstrual education menstruators and non-menstruators receive is often inadequate. It is typically lumped with sex education, stigmatising menstruation. Further, almost no institution-based menstrual education tea... |
[
"Humans are getting taller and taller - will this stop eventually, or will we just keep growing?"
] | [
false
] | null | [
"We're getting taller due to cultural factors, not genes. Nutrition plays a huge role in this, such that our gene's expression will result in taller individuals when we eat healthier.",
"Compare North Korea and South Korea for example. NK has shorter and malnourished citizens compared to SK.",
"A google search ... | [
"Most of the reading I've done on this indicates that the maximum potential height for humans in one Earth gravity is about 3 meters. The square cube law (",
"http://en.wikipedia.org/wiki/Square-cube_law",
") basically sates that for every doubling of height, volume (and hence mass) goes up by a factor of 8. ... | [
"That article also states that the age of menarche has also decreased, is this true? I was under the impression that the age of menarche has actually increased."
] |
[
"If vitamins A, E, and K are fat soluble, how do vegetables have such high amounts of them yet so little fat? Where/how do vegetables store these vitamins?"
] | [
false
] | null | [
"The terms \"high\" and \"low\" are relative. For example a cup of kale (130g) contains 1300% of your daily value of vitamin K, but that is only 1mg of the vitamin. That same cup contains 0.6g of fat, a relatively low amount compared to fat-rich food, but still a lot of fat to easily dissolve 1mg of vitamin K."
] | [
"Again, the devil is in the details. They synopsis of an article which is a summary of a scientific study never provides enough details to form far-reaching conclusions about a topic. In this case, the webmd article states:",
"Researchers say this study shows that the minimum amount of fat required for optimal ab... | [
"That being the case, why does eating vegetables with a fat source improve absorption of those vitamins if there's already sufficient fat in them to dissolve them? (As per the study discussed in this article ",
"http://www.webmd.com/food-recipes/20040727/fat-helps-vegetables-go-down",
" )"
] |
[
"Where does the carbon come from in 'green steel'?"
] | [
false
] | I was reading this morning about green steel production ( ), but I don't understand how fossil fuels can be completely eliminated. As I understand it, renewable sources and hydrogen can be used to heat the furnace, and hydrogen can be used instead of coal to reduce the iron oxide to iron (producing water instead of carbon dioxide). However, steel contains a few percent by mass of carbon, to provide its strength. Where does green steel get that from? | [
"The point of \"green steel\" isn't to completely eliminate fossil fuel use, it's to significantly reduce the CO2 output associated with making steel.",
"The traditional way of making iron metal from iron ore is to place it in a blast furnace along with coke (basically purified coal). The coke gives off CO gas, w... | [
"There are many ways of doing that.",
"It's been more than a decade since I learned a bit about metallurgy, so my memory might be a bit foggy on the subject. ",
"But, you can just burn a bit of biomass along side the hydrogen - that way the carbon comes from the fast carbon cycle, and the steel will technically... | [
"You can also just distill CO2 from the air or produce it via a range of different chemical reactions.",
"To add to this, collecting CO2 from an existing chemical plant will use the least energy. Capture from a concentrated point-source emitter uses a fraction of the electricity vs direct air capture with current... |
[
"Who feels the umbilical cord being cut? Mother, child or both?"
] | [
false
] | null | [
"Neither, actually.",
"The parenchyma of the umbilical cord is made up of something called ",
"Wharton's jelly",
", it's basically a very thick, mucous-ey substance that provides structural support to the important stuff inside (umbilical arteries and vein). There are no nerves in Wharton's jelly, so no one f... | [
"It's attached to the placenta, which comes out shortly after the baby. So they could have left it on and it would have shriveled up and fallen off on it's own. They could have made \"knives\" out of wood, or before that kind of tool-making they could have used sharp rocks or even chewed through it like chimpanzees... | [
"Somehow that made me wonder what the early human did with the umbilical cord. Did they cut it? I know that people in the middle ages \"cut it\" with a little string"
] |
[
"Why are we saying that the strong force is the one which maintains the nucleus while it only acts inside hadrons ? Why wouldn't it be the weak force instead ?"
] | [
false
] | null | [
"The strong force doesn’t only act inside hadrons, but also ",
" hadrons. This is called the residual strong force, and it’s analogous to intermolecular forces between molecules. The standard electric (Coulomb) force acts inside of a molecule to bind the electrons to the nuclei, but different molecules interact e... | [
"I don't have any other analogy that is simple and sufficiently correct."
] | [
"Thanks for the answer. Now I understand :). I probably missed the residual force part when I learned about the strong force."
] |
[
"Isn't it not technically correct to say there are four fundamental forces anymore?"
] | [
false
] | It seems like there's 6 to me. As far as I know, each boson (group) mediates one force: However, it seems that there are two other groups, the Higgs Boson (the mass interaction? Not sure what to call it), and the X and Y bosons (proton decay, iirc). So are these forces just like the others? If not, why, and if so, why do we still seem to stick to those four as fundamental forces? | [
"The Higgs is not the mediator of a \"fundamental\" interaction. The \"four forces\" are gauge interactions, and are mediated by ",
" bosons (the Higgs is a scalar). Gauge theory isn't exactly a trivial subject so it's almost universally omitted in divulgation, but that's basically what is meant by fundamental in... | [
"A gauge interaction is related to a symmetry in the physics of (in this case) fields, the symmetry transformation is a gauge transformation and choosing one (set) of the equivalent field configurations is called picking a gauge. I'm not sure how comfortable you are with mathematics so there is little more I can th... | [
"In order to describe the excitations (particles) of the gauge fields you need four components (time component + 3 spatial components). This is similar to the description of the momentum in Minkowski space as a four vector (time + 3 x space). Much more importantly, the components of gauge fields transform just like... |
[
"Moderna vs Pfizer/Biontech BNT162b1 vs BNT162b2?"
] | [
false
] | There are people that says that the Moderna vaccine should work as well as Pfizer/Biontech because they uses the same spike. Do anyone know how much difference there are between Moderna and BNT162b2 compared to between BNT162b1 and BNT162b2? What was the problem with BNT162b1 that made it fail before phase 3? | [
"You don't need to appeal to the fact that the Moderna and Pfizer/BioNTech vaccines both encode the prefusion full-length spike protein to ",
" that they will have equal efficacy, you can just look at the clinical trial results.",
"The results were not meaningfully different, with the Pfizer/BioNTech vaccine ",... | [
"Why did Pfizer have a significantly stronger CD8 response then?"
] | [
"We don't know enough about the virus or the immune response to it to answer questions about why some responses differ across vaccine candidate, or even to answer questions about whether it matters at all if there are different immune reaction profiles given that we have observed in large-scale clinical trials that... |
[
"Are stars getting smaller?"
] | [
false
] | Correct me if I am wrong, but stars are born in a nebula, which are the remnants of a supernova? If multiple stars are born in nebulae like in the pillars of creation, then surely an individual star will never be as massive as its parent star? | [
"Not all nebulae have to necessarily be supernova remnants. In fact, the supernova remnants are entirely too hot and also posses too much kinetical energy to collaps into a star on its own. Also the total mass expelled in a supernova is entirely too little to form a new star. Of a given gas cloud typically only aro... | [
"No stars are born form massive cold clouds of mostly Hydrogen and Helium. There may be some initial compression from supernovaes or just strong solar winds, but if the cloud is too warm it wont collapse sufficiently to form a star.",
"These clouds tend to be in the 10000s solar mass range, so there is plenty of ... | [
"Thanks a lot! That's definitely cleared things up.",
"To follow on, does this mean then, that there is a trend towards heavier element star formation? And the hydrogen they do possess is from the interstellar gas clouds?",
"Does this mean the interstellar gas is being 'used up' in new star formation and thereb... |
[
"Why can hyperventilating cause lethal changes in pH?"
] | [
false
] | [deleted] | [
"It can’t. Hyperventilating will lower your CO2 levels, which will in turn constrict your cerebral arteries and make you pass out. Then when you’re unconscious you’ll stop being a dick and breathe normally. And your blood pH will return to normal. Nothing lethal about it. "
] | [
"I was gonna chime in as an EMT but this reply sums it up.",
"The only thing I can add is that your breathing is regulated by the Carbonic Drive so as you exhale excess CO2 the need to exhale decreases. So, if you're chilling you breath normally. If you go for a jog, your body starts metabolizing and produces exc... | [
"But as you know, as an EMT, that you would never withhold oxygen from a COPD patient in distress. "
] |
[
"Would botulism leave any diagnostic trace a year after someone suffers from it?"
] | [
false
] | North Korea claims the American student, Otto Warmbier, had a case of botulism before being sedated and falling into a coma. He is now in a vegetative state. The American doctors examining him stated that they found no evidence of botulism, But it is unclear what exactly they meant by that statement. Botulin, the toxin, would presumably have left the body after 4 or 5 months, no? So of course there would be no "active botulism". So my question is, am I interpreting their statement correctly? It either means everything (he didn't have botulism), or it means nothing (because one wouldn't even expect to observe active botulism after more than a year). Which one is it? | [
"Botulinum toxin can cause degradation of the neuromuscular junction, which can be detected on electromyography(EMG) and Nerve Conduction Studies(NCS).",
"The typical findings are as follows:",
"In extremely severe cases of botulism, the neuromuscular junction could be completely degraded leaving the above ment... | [
"Thanks for the great answer."
] | [
"The binding of botulinum toxin E is very strong with an unbinding half time of months. This is why injections of botox into facial muscles must be repeated about every 6 months. So very little botox would be found on muscle biopsy but analytical methods are sensitive and a trace might be found still bound to Acety... |
[
"Is it possible for a liquid (or solid) to be lighter than a gas?"
] | [
false
] | We know liquids can be heavier (denser) than solids (e.g. ice & water or ). What about gases? Google gives me as the heaviest gas (at room temperature) at 11-13 kg/m and as the lightest liquid at 616 kg/m So it seems unlikely, but can it be done using high pressures/low temperatures/gas mixtures? I'm thinking of a material that is 100% liquid/solid, so party baloons and porous , which are solid objects but gas don't count. I guess that for solids you could cheat by making a ball with a perfect vacuum in it, but does a sufficiently strong and light material exist to build such a ball, so that it won't collapse under air pressure? | [
"Yes. Gasses are compressible, so they can have a density that is greater than the usual density at 1 atm pressure. The following website describes how gasses in parts of Jupiters and in stars have densities greater than liquid water.",
"http://www.newton.dep.anl.gov/askasci/chem03/chem03251.htm"
] | [
"Well, it's not exactly what you're asking, but you can get an aluminum foil boat to float on top of a tank of sulfur hexaflouride, so while the aluminum is still more dense, you can get it to appear lighter due to displacement."
] | [
"Those are not the droids he's looking for."
] |
[
"Do we expect DNA to be unique to earth?"
] | [
false
] | null | [
"I would probably not expect an alien to have DNA exactly like we have it. The exception to this could be the theory of panspermia, if microbial life on earth were somehow dropped here by a comet from somewhere else with life.",
"Assuming life developed completely independently, though, I would not expect DNA as... | [
"DNA? maybe, probably not, but there would have to be some kind of hereditary molecule. The fundamental principals of evolution would be expected to hold. "
] | [
"Put it this way : say you had to pick a molecule other than DNA that could play its role in life. Then around this central choice, there are a whole set of other choices of molecules, systems, and organisation to make a different type of life.",
"It's certainly possible that there are many such choices to be mad... |
[
"Since air condenses to form water on a cold surface, can it condense on the surface of cold water?"
] | [
false
] | I am just curious as to whether a solid surface is required for condensation to happen. Also, if it does condense, would there be an increase in volume, or is the rate of evaporation still higher? | [
"Condensation is the transition of water from a gaseous to a liquid or solid state, and it doesn't require a surface. ",
"A cloud is a very common form of condensation. A cloud is essentially water droplets that freely float around because warm vapor-bearing air has entered a cold region where the temperature has... | [
"I do not believe a solid surface is required for condensation to happen. But, in order for you to observe the condensation taking place you'd need a solid present, or some other calculable amount of water to begin with. You can also think of the surface of a solid becoming wet from condensation. At that time, is t... | [
"Increase in volume. Condensation is just some vapour turning into liquid. Indeed if hot air containing vapour were cooled by a lake the vapour would condense and form a liquid. ",
"In the above scenario though you would also have to ask how much water would evaporate off the surface from the latent heat of the h... |
[
"Do other languages have a preferred way to order adjectives?"
] | [
false
] | I learned recently that in English opinion-size-physical quality-shape-age-colour-origin-material-type-purpose, and would like to learn more about it. Has it always been like this? Is it like this in other cultures? Are there theories as to why this developed? | [
"Not to be aggressive but I don't think that's the question.",
"If you say \"a big black and bold guy\" does the adjectives (big black and bold) have a precise order between one another or can they be freely replaced? A bold black and big guy. It's not about the place of the adjectives in the phrase."
] | [
"French is fun, because adjectives have both an order as well as a location (before ",
" after the noun). ",
"If a word is short or has one of the qualities beauty-age-goodness-size, it goes in front of the noun, otherwise it goes after the noun. ",
"As for multi-adjective ordering, the more \"relevant\" an a... | [
"has one of the qualities beauty-age-goodness-size",
"...but only for the basic adjectives with these meanings, such as ",
", ",
", ",
" and ",
". Others, such as ",
", ",
", ",
" and ",
" come after the noun."
] |
[
"Does turning the sound off with a handheld like a Nintendo DS use less battery life?"
] | [
false
] | And if yes, does it really make a big difference? | [
"Short Answer: Yes it will save some battery power, but no it will not make a big difference.",
"Longer Answer: A lot of handhelds have piezoelectric speakers which don't draw much power ~0.1A or 100mA at full power. The DS has a 850mAh battery, meaning you could run the speaker at full power for 8.5 hours. It's ... | [
"Got any sources on that?"
] | [
"If you have an android phone, you can go to Settings->Battery and it will tell you what parts of your phone have been drawing the most power. In this way you can determine (at least assuming you have an android phone) what's eating up the battery for your particular usage pattern. For what it's worth, the screen... |
[
"Why does the moon rotate at that perfect rate so we only see 1 side?"
] | [
false
] | I want to know if it has anything to do with the theory that the moon broke off of the earth as a result of a meteor/comet, or is just random chance. | [
"It's called tidal locking and is quite common. Initially the moon was rotating faster, but as it flexed from tidal forces from the Earth, it acted as a frictional brake and slowed down the moon's spin to the point where the lunar day and lunar month are the same length. Eventually the Earth's spin will slow down... | [
"Eventually the Earth's spin will slow down enough so only one side of the Earth will face the moon.",
"Only if given enough time, but long before that the sun would have destroyed them both, unless future humans can save them in some way. The moon receding and the oceans evaporating will also hinder this process... | [
"For clarity: Earth's gravity is slightly stronger on the near side ",
" than it is on the far side. There's a bit of gravity variation throughout the earth, but that's not what we're talking about here."
] |
[
"Why are particles the size they are and not any other? Why can't there be protons the size of a peanut. What is the underlying mechanic that forces a particle to become a particular size when it is created?"
] | [
false
] | Something I've thought about a while. Are all protons exactly the same size and why? If it is somehow related to the forces they have then what prevents the forces on another proton to not become "bigger" in scale compared to other protons? Why do all the particles share the same "rules" they act on? | [
"Rather than asking, \"Why are protons (and other subatomic particles) so much smaller than us?\" we should ask, \"Why are we so much bigger than protons?\" The answer is very simple: we need to be made up of a huge number of them to have the complexity that we do. \"Big\" and \"small\" are relative terms. On th... | [
"Protons are the size of protons because of the forces that dominate in the micro world. In the macro world, gravity is the king, whereas in the microscopic world there are different \"rules\". These rules are weak nuclear forces, strong nuclear forces, and electromagnetic forces. These 3 forces and the gravity for... | [
"Because it wouldn't be a proton anymore if it did."
] |
[
"Why does your mouth get all cold when you drink water after eating a mint?"
] | [
false
] | [deleted] | [
"Because chemicals in the mint change the behaviour of the proteins in your mouth that sense cold. These proteins/ion channels (primarily one called TRPM8) normally are activated when you mouth gets down to around 12 degrees. However, methnol directly activates these channels, causing your mouth to seem cold. It al... | [
"I doubt it. Different neurons code for the different sensations. So you would end up with a combination of the two. Which I'm sure would just feel very strange."
] | [
"Yes and no. Capsaicin can be inflammatory for sure. Pepper spray down the throat can cause enough inflammation to cause difficulty breathing, and there's potential for damage to the corneas as well as mild damage to epithelial cells that heals fairly quickly. (",
"http://iovs.arvojournals.org/article.aspx?art... |
[
"if a woman uses birth control that also stops her her period, does it actually stop the body from releasing its monthly egg and if not, what happens to the egg without the period?"
] | [
false
] | [deleted] | [
"Most pills (I assume you mean the pill) contain an estrogen and a progestogen, which together suppress these things called 'gonadotropins'. There are two big gonadotropins that the pill is meant to deal with: Follicle-Stimulating Hormone (FSH) and human Lutenizing Hormone (LH). They both get downregulated by the p... | [
"You may also be interested to know that there are hundreds of eggs that never ovulate, even in women who do not take birth control!"
] | [
"You may also be interested to know that there are hundreds of eggs that never ovulate, even in women who do not take birth control!"
] |
[
"If a pipeline is developed to pump sea water into the desert, would that create a natural precipitation system and irrigate the surrounding land?"
] | [
false
] | null | [
"There was a project the British were considering back in the early 1900's called the Qattara Depression project. The idea was to create canals to allow water to flow downhill into a huge area of the Sahara that is below sea level. They would create an inland saltwater lake, and generate hydroelectricity along the ... | [
"Qattara Depression project",
"Here's",
" the Wikipedia article if anyone's interested. Cool topic!"
] | [
"Holy crap, I was reading on that and while they're still pushing for the idea, in the 1950s they wanted to use nuclear bombs to dread the canal... INSANE!",
"\"The core problem of the entire project was the water supply to the depression. Calculations showed that digging a canal or tunnel would be too expensive.... |
[
"How do power companies measure how much electricity you've used?"
] | [
false
] | [deleted] | [
"The meter on the outside of your house. They used to be analog and a meter reader would come to your house each month to record how many kwh you've used and reset it. Now they are largely digital and the company does all of that remotely. "
] | [
"The old spinny disc meters worked by diverting a small amount of the power being used (~2 Watts) into spinning said disc. Since the power diverted is proportional to the power being delivered, you can track how much energy is being consumed by counting revolutions of the disc, which is what the dials above the dis... | [
"It actually depends on where you are.",
"Some power companies use monthly estimates based on the type of accomodation you live in along with ambient conditions and time of year, and correct any offset when they send out personnel to verify these meters.",
"These days, power meters are digital and are capable o... |
[
"Is there a positive correlation between age at which mating occurs and length of life in humans?"
] | [
false
] | There was a study done on fruit flies in the 1970s that got the flies to live "significantly longer" within 12 generations. I was wondering: (1) what "significantly longer" means, especially in terms of proportionality, and (2) have we been seeing these effects in humans? Has the experiment been performed on any other animal species? | [
"The effect on female fruit flies is significant. Virgin females live about twice as long as those raised with males. Very generally, female fruit flies are on the losing side of the battle of the sexes. They devote a HUGE chunk of their energy and resources toward reproduction when they've mated.",
"I'm not awar... | [
"It has nothing to do with genes. It's simply that reproduction is really really hard on female flies. They lay eggs nearly constantly from mating until death. That's a huge amount of energy expended and wear and tear on the body. Nothing more deeply significant than that. "
] | [
"Is this expressed genetically??",
"Meaning, is the scientist, in effect, putting artificial evolutionary pressure on the group to live longer?"
] |
[
"Does this hadith below have any scientific meaning or importance?"
] | [
false
] | null | [
"Nope"
] | [
"So it's fake?"
] | [
"I don't know what you are referring to by \"it\" and what you mean by \"fake\", but nothing like that that happens during intercourse has any impact on the appearance of the child."
] |
[
"Why doesn't lightning occur in fog?"
] | [
false
] | The way I understand is that fog is basically just clouds on the ground, so why so we have lightening in the up top clouds and not the down below clouds? | [
"Thunderstorms are the result of convective activity - i.e., rapidly rising and falling air due to differences in temperature and moisture content in a parcel of air relative to the air around it. This strong vertical motion leads to a separation of charges within the cloud; lightning is the result of this charge s... | [
"Or between cloud and ground. Although the majority are inter cloud discharges."
] | [
"Interestingly enough I believe that ",
" the voltage difference needed to break the thin layer of non-conductive air and discharge would be orders of magnitude smaller than that needed for a cloud to earth discharge. In the latter case, the insulating layer of air is a few kilometers thick (and certainly much le... |
[
"What would happen if you submerged your hand in Mercury?"
] | [
false
] | Mercury is dense. Ignoring the poisonous vapors causing brain damage, could one submerge their hand into Mercury? | [
" I've put a finger in mercury before. I made sure there weren't any nicks or cuts in my skin and did it quickly. Obviously I wasn't trying to breathe any vapors in. It feels \"heavy\", it was hard to sink my finger into it. The liquid seemed like it was squeezing my finger from all directions. Really, it didn't fe... | [
"When you say \"Mercury,\" at first I thought you meant the planet. Chemical names don't need to be capitalized.",
"The vapour pressure of mercury actually isn't high. The main danger comes from contact. Yes, one can submerge their hands into mercury - in fact, back in the days, miners did gold extractions with m... | [
"Ignoring all bad effects and such, yeah, you could, but you'd have to force your hand in.",
"Mercury, at 13.5g/cm",
" is so much more dense than I, that it would only take 6154 cm",
" of it, to equal my weight (or six liter).",
"I'm absolutely horrible at eyeballing, but I'd say that my skinny arm is about... |
[
"What is the surface area and volume of a Proton, Neutron and electron?"
] | [
false
] | null | [
"Well, we know there's three so-called \"valence\" quarks, the quarks that determine the properties of protons and neutrons and all other baryons. But there's also gluons and all the interactions of the strong force that come with them. So think about a proton or neutron. They have about 940 MeV/c",
" in mass, bu... | [
"To begin we need to separate the subatomic particles into two classes, Composite Particles, and elementary particles. ",
"The electron is an elementary particle and pjfoster is correct that the electron size really cant be determined. This is because the mass of an electron is so small that the electron exhibi... | [
"Although in reality they're a blob of quarks and gluons, and when you count up all the quarks you'll find that there are two more up quarks than anti-up quarks and one more down than anti-down. Strange and anti-strange are in equal numbers."
] |
[
"Is there a mathematical definition of a chaotic system?"
] | [
false
] | I know the general definition of chaotic system is a system where very small changes in the initial conditions creates extremely large changes in the end result. (Like dropping a double pendulum). I was just wondering if there is a mathematical standard for determining whether a system is chaotic. | [
"The definition of chaos is still sort of in the works, in terms of a precise, abstract definition but there are a few things that characterize it. One of them is the Lyapunov exponent that was already mentioned, which is a measure of how fast nearby initial conditions diverge as they evolve. This is a measure of t... | [
"Thanks! Answered my question perfectly."
] | [
"Thanks! Answered my question perfectly."
] |
[
"Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology"
] | [
false
] | null | [
"Is true that the monolith discovered in Utah was not man made? If so how was it formed?"
] | [
"Do to a bot glitch, this was posted twice. This is the thread that was removed, so I am letting you know you should ask your question in the main post.",
"Sorry!",
"https://www.reddit.com/r/askscience/comments/k0tnr1/ask_anything_wednesday_biology_chemistry/"
] | [
"The field of psychology has taken some serious hits lately regarding made-up study data and false research, which has led to questions about the entire field's validity. What is the psychology field in general doing to address these problems and concerns?"
] |
[
"Do furry pet owners experience respiratory problems at a higher rate than non-pet owners, due to hair/dander in the home?"
] | [
false
] | I appreciate there would be a lot of confounding variables in any such study, but have any attempts been made to measure? | [
"Asthma, allergic rhinitis, and eczema are all statistically more prevalent in children of households with animals present than without",
". This was a hospital-based study that looked at Qatari children, so the mix of animals (cats, goats, birds) weren't exactly the same mix as you'd find in, say, the USA, but t... | [
"\"sometimes in response to the very variables you're trying to study.\"",
"We run into this a lot in economics. Economics is particularly fun because you have to predict how people may respond to your study, further adding issues."
] | [
"and that those symptoms persist at a higher rate than experienced by non-animal-owners even if the household goes animal-free.",
"Is it a causal link? Or is it because non-animal-owners are a mix of people with and without respiratory issues at approximately population-average proportion and people who'd gone an... |
[
"Has there ever been more living beings in the planet than right now or is this the period that’s seen the most life?"
] | [
false
] | Is it even possible to answer this question? | [
"Count bacteria, ignore animals, plants and similar large living beings because their number is negligible anyway. But I would be surprised if we know the number of bacteria today or in the past well enough to make any useful estimate."
] | [
"I took a course in geology, where the teacher showed a slide of the populations of living beings over time. Aside from several population extinctions, life has always come back stronger over time. At this point, however, we are in the beginning of another extinction. ",
"https://en.m.wikipedia.org/wiki/Holocene_... | [
"Correct me if I'm wrong, but the data you saw was probably number of species, not number of individuals. Total population of all individuals of all species would be really hard to estimate and also not very meaningful--e.g., an individual whale has much more ecological importance than an individual krill."
] |
[
"In batteries, does the metal matter?"
] | [
false
] | I'm looking at the galvanic cell, here: And as near as I can tell, the electron flow is from the anode metal to the cathode's . It's just a redox reaction directed through a wire. So the zinc sulfate should be interchangeable with other electrolytes, and the copper metal should be interchangeable with other metals, without altering the overall voltage. Is there any reason this shouldn't be the case? Edit: I replaced the two and am getting 2.26V of current, but the light bulb isn't lighting up. What gives? | [
"I replaced the two and am getting 2.26V of current, but the light bulb isn't lighting up. What gives?",
"The choice of metals and electrolyte determines your voltage, but the current is largely determined by the surface area of the metals in contact with the electrolyte. If you are using small beakers it is unli... | [
"Replacing the zinc sulfate with another electrolyte will shift the equilibrium of the oxidation of zinc toward its ion (Le Chatelier's principle). Changing the copper metal is a bit different. The reduction of the Cu",
" ion is energetically favorable, whereas the reduction of another metal such as Na",
" is... | [
"So replacing the zinc sulfate should speed it up then, yes? Because I'm looking at it here- I replaced the zinc sulfate with sodium sulfate- and absolutely nothing is happening. Voltmeter says no current is flowing.",
"In the left beaker I have zinc metal in sodium sulfate (1M), in the right beaker I have copper... |
[
"If I am riding in a bus traveling 60 mph, and I throw a ball 30 mph from the front the bus to the back of the bus, what exactly is happening? Is the ball moving, or is the bus accelerating away from the ball at 30 mph?"
] | [
false
] | null | [
"The people in the bus will see the ball travelling at 30 mph backwards. That is, until it hits the floor or the back of the bus.",
"Someone standing on the side of the road, looking into the bus as the ball is being thrown will see the ball travelling 30 mph forward, in the direction that the bus is going, but a... | [
"To add to the current top responses, I want to refer to the \"or is the bus accelerating away?\" part. In the frame of reference of the ball, the bus is ",
" away from the ball at 30mph, but not ",
". That is a common source of confusion that I wanted to highlight: things are moving, in this frame of reference... | [
"Everything is based on the reference frame of the observer. In this case the speeds can be added linearly, based on the observer. An observer outside will see the ball will see the ball moving forward at 30 mph (and the bus at 60 mph)",
"An observer on the bus will observe the ball to be moving backwards at 30 m... |
[
"When talking about the electromagnetic field and the different frequencies, what exactly is the medium that is vibrating?"
] | [
false
] | As I understand it, the different in visible light and radio waves is the difference in frequencies or vibrational speeds. What is vibrating? Since these things can travel through a vacuum, I assume that it isn't matter, right? | [
"This was the question that drove people to assume the existence of 'luminiferous ether' (literally, light bearing background substance) in the 19th century. Wikipedia actually has a ",
"pretty decent discussion",
" of the history of the idea and how it was abandoned.",
"What you're doing is assuming that bec... | [
"There is no medium vibrating. In a plane wave at a particular fixed point in space, for instance, the electric field will have the form ",
"(t) = ",
" cos(2πf t). So the frequency f describes (via f = 1/T) the period of the electric field oscillation from ",
" to -",
" and back to ",
"."
] | [
"I really don't understand what you are trying to ask. The wave is an oscillation of the electric and magnetic fields. I explained this in the top-level response."
] |
[
"Do humans have any adaptations specifically for combat?"
] | [
false
] | null | [
"While humans are not as strong or fast as other large animals, there is one physical adaptation that humans have developed better than any other animal: long distance running. No other animal has the long distance capacity that humans have, and it's widely theorized that a big part of human development and success... | [
"Our brains let us develop weapons and build defenses. We are also great long distance runners who can work as a team to track and literally run after prey until they die of exhaustion"
] | [
"Biological anthropology minor here (majoring in Paleo, so it's kind of legit, I suppose.) Not only are we adapted for running/long-distance walking, but the way our shoulders are canted allows us to throw things, which is quite useful in a fight. The acetabulum (sort of ball-and-socket joint) of the shoulder blade... |
[
"\"Solar wind induced magnetic field around the unmagnetized Earth\" - Why would this not work on mars? Or would it work if the atmosphere would be more dense?"
] | [
false
] | null | [
"I really wish people would stop trotting this factoid out.",
"IT'S NOT TRUE.",
"Titan is far smaller and less massive than Mars, yet has an atmosphere thicker than our own. That alone disproves the idea that Mars is too small to hold an atmosphere. ",
"There is no simple answer to why Mars has a thin atmosph... | [
"Correct - the solar wind ionizes the upper layers of the atmosphere, which protects lower layers from large amounts of radiation. This only works if your atmosphere is dense enough to begin with that the ions are likely to form a consistent barrier to radiation."
] | [
"Yeah, I see this around a lot so it's not surprising it gets repeated. There's a nice plot that gives an insight here ",
"http://abyss.uoregon.edu/~js/ast121/lectures/lec14.html",
". You can see that in terms of Temp vs. Gaseous escape velocity, Mars isn't far away from Venus. It can easily retain a CO2 atmosp... |
[
"Why do people with tourettes disease never yell nice things?"
] | [
false
] | null | [
"Hello, I have Tourette's with coprolalia. (Incidentally, the majority of words or phrases that I do say aren't yelled.)",
"Two of my less offensive articulate tics have been \"I love you\" and \"I miss you.\" Still, not the most comfortable things to say to the stranger next to you on public transit. ",
"Ti... | [
"As a general rule, don't confuse the way a movie portrays a disorder with the actual disorder."
] | [
"Don't get tourette's confused with coprolalia (yelling out swear words/inappropriate shit). The latter is independant of but can be a symptom of the former."
] |
[
"Is there any physical limit to the Periodic Table? Or could we theoretically just keep fusing elements together to make heavier ones?"
] | [
false
] | My basic understanding is that heavier elements are typically made when 2+ lighter elements are fused together (e.g. inside of stars, or synthetically in a lab). If there were no technological restrictions, is there any limit to how high the periodic table could go? I found an article on that might contain some sort of answer, but I didn't really follow it. Thanks! | [
"\"My basic understanding is that heavier elements are typically made when 2+ lighter elements are fused together\"",
"Absolutely right.",
"\"could we theoretically just keep fusing elements together to make heavier ones?\"",
"No, not indefinitely.",
"What causes a nucleus to continue existing is its stabil... | [
"The physical limit would be at the proton drip line, when it is just impossible to bind another proton."
] | [
"It's 3:00am here and I have no idea why I'm still up, but here is something that might help answer your question. I'm too tired to try to explain it though... ",
"http://en.wikipedia.org/wiki/Periodic_table#Future_and_end_of_the_periodic_table"
] |
[
"What does it mean for a unit of light to have a certain wavelength?"
] | [
false
] | [deleted] | [
"A good rule of thumb is that ",
". This means that any interaction with matter - absorption and emission - must occur in discrete chunks of energy which we call photons.",
"When we say light is an electromagnetic wave - we mean that it is a change in the electric and magnetic fields that move through space to... | [
"Light is an electromagnetic wave, and if you were to watch the electric field as it passes by you'd expect to see the field oscillate at the frequency of the light wave. For example if you put an antenna there, the light may cause an AC current in the wire at that frequency. The wavelength is how far the light tra... | [
"i`m no scientist, but all photonic radiation (radio, light, uv, etc) is self propagating Electro-Magnetic radiation. i capitalize to emphasize that it is actually both fluctuations in the electric field and the magnetic field at right angles to each other. since an electric field will induce an magnetic field (at... |
[
"What is the evolutionary 'purpose' of flies, fleas and cockroaches?"
] | [
false
] | null | [
"You misunderstand evolution. It doesn't create things it needs. Things are created randomly, and if they survive and prosper, they survive and prosper.",
"They have no purpose, they have features which randomly allowed them to prosper."
] | [
"OK, I understand this better than the first comment from Osymandius - I do understand evolution, I suppose it sounds like my question is coming from an 'intelligent design' standpoint, which is NOT my intent! ",
"Basically, while being annoyed by these creatures I often ask myself 'what the hell do they do but a... | [
"OK - how about the question I maybe should have asked: if these creatures (flies, mosquitos, cockroaches, fleas) didn't exist, would there be any detriment to ecosystems anywhere? "
] |
[
"In the context of the Earth's climate changing drastically on its own over time, why is the current climate change bad?"
] | [
false
] | [deleted] | [
"Change is disruptive. Was the ice age bad? Not from our historical perspective, but for the species and societies wiped out, it was. Even those who managed to adapt found it a challenge. When you've built up a massive amount of infrastructure, it's potentially much worse. Sure, we have more mobility now, but deali... | [
"First, it’s good to see someone asking sharp questions about climate change without getting all conspiracy-ish.",
"a climate that's good for people to live in",
"Yes, but ",
". In the short term, people might like it if it were sunny and room temperature everywhere. In the long term, a climate that’s good fo... | [
"Then couldn't you justify stopping the Earth's natural climate change if it happened to be heating up independent of human activity?"
] |
[
"How recently did we discover/understand evaporation?"
] | [
false
] | Were people 10,000 years ago like, "Yo, Where did my water go?" What theories did we have about evaporation before we knew what was actually happening? | [
"There's evidence of large organised Salt production facilities dating back 5000 years or more. The easiest method for salt generation in Ancient cultures would have been to flood salt flats with water, dam them and wait for the water to evaporate.",
"Evaporation needs to be well understood (i.e. what environment... | [
"I feel it would have been for a long time. Easily 100,000 years. Considering there would have been a clear observational understanding that water that was dripped on hot surfaces first makes them wet, then steam/water vapour would come off and eventually wet spot would dry. I also feel that people for a long time ... | [
"I'm not so sure about that. It's not just the brain and nutrition. We grow up with the expectation that everything has a scientific explanation today.",
"See the history of ",
"spontaneous generation",
" of life for example. Mice forming from wheat. An absurd idea today, but it was taken seriously for a long... |
[
"Would this matter to energy converter work in principle?"
] | [
false
] | null | [
"Yup. Some people have thought of it too (though there's variations). It's really sci-fi-ish, but there's nothing wrong with it theoretically and is in fact maximally efficient."
] | [
"Give it a charge and hold it in an electric field? It would be safest to do it out in space and if anything goes wrong it could be towed away from Earth."
] | [
"How do you keep the BH in place?"
] |
[
"Hypothetically, an electron can travel infinitely far from its nucleus, right? If so, what is the furthest we've ever measured?"
] | [
false
] | Of course it would be rare for the electron to fall outside its cloud but it happens, right? | [
"An atom with an electron orbiting really far from the nucleus is called a ",
".",
"It can be as far as a millimeter: ",
"http://prl.aps.org/abstract/PRL/v100/i24/e243004"
] | [
"Let's look at the ground state of the hydrogen atom. When we solve Schrodinger's equation, we discover that the probability density for the electron goes like a decaying exponential, in the characteristic size of the atom, that is\nP(r) ~ e",
"r/a0",
" \nwhere a0 turns out to be about 1/2 an Angstrom,",
"We... | [
"Electrons can be liberated from their atom and go completely free, then their distance from the atom is of no particular interest since they aren't orbiting it.",
"If you're asking what the largest observed orbit of an electron is, you'd have to wait for a bit for an answer.."
] |
[
"How do gravitational slingshots work?"
] | [
false
] | In order for the Voyager 1 space probe to escape the suns gravity it had to slingshot around Jupiter and Saturn. What happens when the probe slingshots around a planet? Where does the added velocity and energy come from? | [
"The added energy is coming from the motion of the planet. As the planet is in motion, it is easy to show that the time spent approaching the planet can be greater than the time spent leaving. Net result is a greater velocity to the spaceship. The planet slows down by a relative amount based on mass."
] | [
"Let's say you're behind the wheel of a truck stopped at a red light, and a kid tosses a (perfectly elastic) rubber bouncy-ball at you at 30 mph. What do you see? Well you'll see a bouncy-ball coming at you at 30 mph, then bouncing off and flying away at 30 mph. Good. Easy. ",
"Now say you're chugging along ... | [
"The added velocity comes from the planet. You have to come from the \"backside\" of the planet, that is, the side opposite the direction of its velocity vector. As you approach the planet, it's pulling you toward it, increasing your velocity in that direction. If you get your timing and distance right, you'll be f... |
[
"If visible light is photons, then is all electromagnetic radiation photons? If so, why does its wavelength give the photons certain properties (e.x. harmful to humans, visible, can pass through matter)?"
] | [
false
] | null | [
"I'm not sure I'd say that gamma is the highest - that would seem to imply that there is a highest energy, which doesn't make sense. ",
"A better way to say it is that we usually use the name \"gamma rays\" to describe photons with frequency equal or greater than 10 exahertz, and that we don't have any higher cla... | [
"Yeah that mostly covers my question. Thanks for taking the time to write that out!"
] | [
"Yeah that mostly covers my question. Thanks for taking the time to write that out!"
] |
[
"Why is calcium a metal? Why does it seem to have so few obviously metallic properties?"
] | [
false
] | null | [
"Calcium the element is a metal and has all the properties of one this is what it looks like ",
"http://f.tqn.com/y/chemistry/1/L/w/3/1/Calcium_1.jpg",
"\nThe calcium you're probably talking about are compounds like calcium carbonate or whatever large compounds it makes in our bodies."
] | [
"https://en.wikipedia.org/wiki/Calcium#/media/File:Calcium_unter_Argon_Schutzgasatmosph%C3%A4re.jpg",
"Even a better representation of what metallic calcium looks like."
] | [
"Metal is just a classification based on chemical and physical properties. The reason that calcium (and magnesium and beryllium and other alkaline earth metals as well as alkali metals like cesium) are different is because in pure form, they are very reactive due to only having 1 or 2 electrons in their valence she... |
[
"Why is \"hydrogen carbonate\" also called \"bicarbonate\"?"
] | [
false
] | I don't know if it's a stupid question, and I haven't been able to really find this since the keywords bring up so many other things about the bicarbonate ion and whatnot, but what is "bi-" about bicarbonate? -- meaning, since as far as I know, "bi-" means/implies both, or two, so I'm getting lost where that name would come from and/or how it's tied to "hydrogen carbonate" (though I understand how it is hydrogen carbonate since it's HCO3) | [
"Bicarbonate is a historical name, and the official name is now hydrogen carbonate. Historical names are hard habits to break though, and continue to be used in many cases. The Bi doesn't mean two in this sense, in chemistry, two is represented with Di, as in dihydrogen. The bi refers more to the fact that's it's a... | [
"That makes sense. and also something like oil of vitriol as a historic name for sulfuric acid. But, yeah, I was confused since I knew that \"di\" is two, so why would \"bi\" be used, but this helps!"
] | [
"Historical names can be a pain to deal with, like acetylene for instance, which is a common chemical. The Ene ending indicates a double bond now days, but acetylene has a triple bond, and it doesn't have an acetyl group and it's official name is ethyne now. So in some cases it can even be deliberately misleading w... |
[
"Is the lift force generated by a wing greater than the resulting drag force?"
] | [
false
] | [deleted] | [
"No, I would not describe it as a mechanical advantage. A wing is not multiplying your force input.",
"You have an engine which is pushing the airplane forward, powered by fuel. You have gravity pulling the airplane towards the ground. As the airplanes moves forward, the reactionary forces on the wing will be poi... | [
"No, I would not describe it as a mechanical advantage. A wing is not multiplying your force input.",
"You have an engine which is pushing the airplane forward, powered by fuel. You have gravity pulling the airplane towards the ground. As the airplanes moves forward, the reactionary forces on the wing will be poi... | [
"Yeah, typical lift to drag ratio of an airplane is something like 15-20. You can imagine for the wing itself it is even larger since the fuselage, landing gear, etc isn't built to generate lift."
] |
[
"Why was the 2009 H1N1 pandemic less deadly than the H1N1 pandemic in 1918? Was it a less dangerous disease, or did we just have better medicine?"
] | [
false
] | null | [
"In addition to what others already wrote, it's also worth pointing out that the 1918 H1N1 virus was a very different one than the 2009 H1N1 virus. ",
"The HxNx classification system is fairly coarse and is based on two surface proteins of the viruses, but doesn't take other differences into account."
] | [
"I'm reading a scientific review about it that says \"Many data from that era [1918] suggest that almost all deaths resulted from secondary bacterial bronchopneumonia\" and also \"[1918] featured an enormous and ",
" mortality in healthy young adults.\" ",
"They don't mention anything about malnourishment or WW... | [
"Probably a combination of factors. In 1918 at the end of WW1 there was widespread malnutrition, soldiers with gas damage to their lungs, and generally less sanitary living conditions that may have affected people's immune function and made the pandemic more deadly. They didn't have specific medical resources like ... |
[
"Can wormholes be used for long distance communication?"
] | [
false
] | null | [
"Such hypothetical / speculative / open-ended questions are better suited for our sister-sub ",
"/r/asksciencediscussion",
". Please post there instead."
] | [
"Already removed"
] | [
"Sounds good, I reposed this over there. ",
"https://www.reddit.com/r/AskScienceDiscussion/comments/b4zrp6/can_wormholes_be_used_for_long_distance/",
"",
"Shall I delete this thread?",
""
] |
[
"Why is symmetry attractive?"
] | [
false
] | AFAIK, one of the features that best predict if someone is thought of as attractive regardless of things like cultural background is symmetry of the face. I think this holds true not only for humans but also for animals. A typical handwavy explanation for this is that this is an indicator of 'good genes'. But what does that mean exactly? And why are good genes making symmetric faces? Or Is there another explanation? | [
"Symmetry is a signal for fitness, as you suggest",
". This link should provide a great starting point.",
"Fluctuating asymmetries (FAs) are nondirectional (random) deviations from perfect symmetry in bilaterally paired traits. In nonhuman animals, FA in body traits reflects developmental instability (inability... | [
"Those are some interesting resources, especially the first one. Especially when they point out that several 'disadvantages' like psychosis are correlated with asymmetric faces, so there seems to be some truth to this signaling some favorable genes. The mechanisms would be interesting of course"
] | [
"Because our DNA basically maps both sides as the same thing, but reflected (excluding some internal structures), if it's not matching or almost matching, there's a possibility of genetic or other health problems. Which an organism looking to continue their species would like to avoid (on an instinctual level)"
] |
[
"What are examples of physical processes that involve wave function collapse?"
] | [
false
] | I learned in an intro quantum mechanics course that taking measurements on quantum particles results in a collapse of their wave functions to a narrow spike, and that the measured quantity assumes a definite value after the measurement. Can anyone give me some examples of these types of measurements? The professor and text were exceedingly vague on this. | [
"The professor and text were exceedingly vague on this.",
"They're vague, and frustratingly so as I recall, because they don't know. They may have an opinion, like ",
"/u/RetraRoyale",
", who doesn't think it's a physical process, but there's no broad consensus in the field anyone can point to you to. It's ... | [
"It's not an opinion. It's a fact.",
"Absolutely not. Decoherence is a physical process. Objective collapse theories have their share of proponents. You should not insist something as fact when there is widespread disagreement with your \"fact\".",
"It doesn't matter. Science is not done by majority vote or de... | [
"Imagine that you've got a model universe with a car driving down a highway. You predict what it is going to do: keep going straight. Now someone comes along and tells you that your model is wrong: the world is not that simple. In actuality, there's a big block of concrete in the middle of the road. So you rehash y... |
[
"At what evolutionary distance can two animals no longer reproduce?"
] | [
false
] | You can mate within the same species like breeding dogs. However, we cannot mate with monkeys despite sharing a common ancestor. My question is as follows: Say animal A is geographically separated and some because animal B and the others become animal C. At what point are B and C too different to reproduce with each other? From my understanding it is when they are of a different genus. What change in them (genetically or otherwise) marks that point or becomes formidable enough for the DNA not to mix? I'm not a science major and I've tried to word this as well as I can. I hope I've at least gotten the main question across properly. | [
"Essentially a single major change (say a chromosome splitting) could be enough the separate a group of individuals in a small number of generations; on the the other hand thousands of (functional) single nucleotide polymorphisms might not be enough -- it all depends on what the genes actually do, how it affects th... | [
"There's a lot to consider here. First is that we can't really look at \"evolutionary distance\" in terms of any meaningful units. This is because the \"distance\" in question isn't just gene frequencies. ",
"Also keep in mind that \"species\" is not a well-defined word. Sometimes we designate species based on mo... | [
"no, a common genus has absolutely nothing to do with this. This ability doesn't really have anything to do with anything as far as classification goes. The process of turning a fertilized egg into an animal that can live is extremely complicated and involves the use of millions of genes. If these particular gene... |
[
"What occupies most of the space of an atom?"
] | [
false
] | [deleted] | [
"The electrons orbit the atom at various radii. This conglomerate of the electrons orbiting the nucleus is commonly know as the \"electron cloud\" and that is the majority of the space an atom occupies."
] | [
"They can be treated as such - that's what a wavefunction is."
] | [
"The wavefunction can tell you the probability density of finding an electron over a defined space - and your electron orbital is usually defined as \"the volume in which there is 95% chance of finding the electron.\" Until a measurement is made (i.e. an interaction occurs, thus the ",
"wavefunction collapses",
... |
[
"Why is the Ohio River considered a tributary to the Mississippi River and not the other way around?"
] | [
false
] | If a tributary is a river that flows into a larger one shouldn't the Ohio river be considered the main river/source? | [
"Generally, the definition of which stream is a ",
"main stem or trunk",
" stream vs which is a ",
"tributary",
" is not always consistent, or rather, there are a few different properties of a river network that are used to distinguish trunks and tributaries. If you're starting from scratch, the definition ... | [
"Many researchers have mapped the geomorphology of the Mississippi & Ohio River Basins. Roger T Saucier is considered to have the most accurate model(1974, 1982 multiple pubs), but these are largely based on the work of Fisk from 1944. Because I’m away from my books right now, this will largely recount these from... | [
"Thanks! I have the plates digitized and on my computer for GIS purposes, but my article is at the office."
] |
[
"Big Bang question."
] | [
false
] | [deleted] | [
"Is the big bang proven science?",
"There is no such thing as \"proven science\". Scientific theories are all subject to disproof with new evidence, and there are no \"proven theories\" in science. If a theory were ever to be declared \"proven\", in that moment it would leave the domain of science, and enter phil... | [
"No, we don't know anything about what was before the Big Bang and the Big Bang theory makes no attempts to explain this; it only explains the conditions of the early universe. In fact, it is actually impossible to see further back than ~400,000 years because the universe was opaque to EM radiation up to then, as p... | [
"The evidence that there was a big bang at the beginning of the universe is extremely compelling.",
"We see the afterglow of the big bang in the cosmic microwave background. This is probably the best direct evidence.",
"We measure that the universe is expanding directly. This is pretty direct evidence.",
"T... |
[
"Can motion of planets produce sound ?"
] | [
false
] | null | [
"This is a deceptively difficult question to answer because it hinges on how you define sound and gets into a philosophical debate about cause in a complex system. I'm going to define sound as sound waves that exist on a human or \"larger than human\" scale. Sound that theoretically could exist at an immeasurable s... | [
"Replace planet with any arbitrary object and you get an equally deceptively question. I don't think this question make sense at all."
] | [
"Usually when people ask it about a planet they mean is there is a distinctive \"planet motion\" sound.",
"The question makes sense to ask with the context of moving things frequently producing sound on earth."
] |
[
"Is mass directly proportional to inertia?"
] | [
false
] | null | [
"\"Inertia\" by itself doesn't have a mathematical expression, so it wouldn't be precise to say yes, but Newton's second law states that F = ma, where F is force, m is inertial mass, and a is acceleration...so if you're talking about inertia as a resistance to acceleration, then yes, it's proportional. (So doubling... | [
"Of course, this isn't so straightforward when discussing rotation, where moment of inertia is more relevant than actual mass.",
"But it still remains essentially true, since you can deconstruct the rotational inertia of an object and explain it solely in terms of 'regular' linear inertia of the components of the... | [
"Adding onto this, I find it useful to view inertia as a resistance to a change of state of an object. ",
"In mechanics, an object with no external forces will maintain some constant velocity and direction. Now when a force is applied to change the velocity or direction, mass (inertia) is the resistance to that c... |
[
"Why does stress lead to us sleeping badly? It would seem evolutionary advantageous to be able to recharge peacefully during times of stress"
] | [
false
] | null | [
"Stress hormones are released by the body when it perceives that it is in danger or has to mobilize extra resources in order to succeed. When you see it like this, you can realize why being more sleepy is disadvantageous. Stressful situations call on us to mobilize everything and be in fighting condition to address... | [
"Yes, but why are they being released when we are in no immediate danger and try to relax? Is it just a loop in the brain that keeps running for a while after the original \"stress impulse\"? "
] | [
"Because your body doesn't think it isn't \"in danger\". Your body operates primitively and isn't designed to handle modern day stresses that can't necessarily be faced directly. "
] |
[
"Is the gravity of Ceres strong enough to allow for walking or running?"
] | [
false
] | Given Ceres' extremely low mass, would it feel more like Zero-G, or would the gravity "keep you grounded", so to speak? | [
"Ceres has just under 3% of Earth's gravity, at about 0.27m/s².",
"This means if you weigh 200 pounds on Earth, you would weigh 6 lbs. on Ceres.\nWalking would be very difficult, nearly impossible unless you moved at about a snail's pace. Running could have an equivalent if you leaned forwards until you were near... | [
"Not really, according to ",
"wikipedia",
", the escape velocity of Ceres is 500m/s. However you could jump about 35 times higher than on earth."
] | [
"You'd actually take off and land with the similar velocity as you would on earth. It just takes gravity longer to slow you down and then speed you back up.",
": misunderstood your question, sorry. No, I don't think terminal velocity is a meaningful term on Ceres. You'd keep accelerating until impact."
] |
[
"Where do photons, gluons, w and z bosons come from?"
] | [
false
] | null | [
"What do you mean \"come from\"? They're fundamental field excitations. Imagine the skin of a drum. Now you strike the skin, and it begins vibrating. Particles are like that vibration, ",
"they're \"excited states\" of fields that permeate and make up the entire universe",
"."
] | [
"the quark is itself an excitation of the quark field, and has properties of \"color charge\" in addition to electric charge. And like the electric charge excites the electromagnetic (photon) field, the \"color charge\" excites the strong (gluon) field(s)."
] | [
"well the photon is absorbed (destroyed) when the electron gains energy, and created when an electron loses it (among other processes). It's the other processes you need to think about really when you talk about gluons. All of these particles carry momentum away from some fundamental fermion(s) and give it to some ... |
[
"How can both black holes and gravitons exist?"
] | [
false
] | If gravity is carried by particles that move at the speed of light, how is it possible for a black hole to transmit gravitational effects to outside its own event horizon? | [
"Actually it's not necessary to think about gravitons (quanta of the gravitational field) in order to have this question-- the same applies to the classical gravitational field and gravitational waves, the latter of which are how changes in the former propagate, and do so at the speed of light. As a star collapses,... | [
"It's a bit of a misnomer to say that forces are \"carried\" by particles. It's not as if the electric force works by two charges shooting photons at each other, for example.",
"A black hole forms from a collapsing star. That star had a gravitational field, and that gravitational field won't disappear simply beca... | [
"That's not true. The Casimir effect and virtual particles are very seperate from gravity."
] |
[
"Whats the difference between moving your arm, and thinking about moving your arm? How does your body differentiate the two?"
] | [
false
] | I was lying in bed and this is all I can think about. Tagged as neuro because I think it is? I honestly have no clue if its neuro or bio. | [
"There is a fair amount of evidence from fMRI, PET and EEG studies that show involvement of the primary motor cortex in motor imagery tasks. I've performed a bunch of experiments with EEG motor potentials during ballistic movements (they evoke sharp, strong and easy to detect signals in the EEG), and I've even been... | [
"I'd suggest that you ",
" reacting to a changing environment or stimulus. It's just that the changes/stimulus come from your internal landscape and not from the exterior one. "
] | [
"I'd suggest that you ",
" reacting to a changing environment or stimulus. It's just that the changes/stimulus come from your internal landscape and not from the exterior one. "
] |
[
"If sentient marine life were to evolve, say, on another planet, would they be able to advance as far technologically as humans?"
] | [
false
] | This question occurred to me when I was reading a post awhile ago about how dolphins are now considered more intelligent than chimpanzees. It doesn't seem inconceivable that on another planet that marine life could evolve to have human level intelligence, but would their aquatic environment stifle technological innovation? Shelter wouldn't be necessary, nor would the wheel, and fire, along with the advances that implement it such as metalwork would be impossible, so would the species be able to advance beyond the the tribal stage of our stone age ancestors? It's an interesting topic to me. Tl;dr How far could sentient marine life advance technologically? | [
"Availability of high-density energy sources would be key. Is this an aquatic planet, or are there land masses, covered with plants?",
"If it's a pure ocean planet, it would be damn difficult. You'd be limited to hydrogen reduction of metals, and cold welding. No smelting (I don't think you could build protective... | [
"I've thought about this concept as well. I'm not sure how much of our technology they might be able to create but there might very well be some technology that we haven't even conceived of that only an aquatic species would invent, or at least that would come naturally to an aquatic species that wouldn't to us. ... | [
"Actually, there are ",
"several correct plurals of 'octopus'",
", including that one. At least if you go by the Merriam-Webster definition. "
] |
[
"In this video of a car on two wheels, why do the wheels in the air stop spinning. At least one should be powered by the engine, right?"
] | [
false
] | null | [
"This is not accurate at all.",
"All cars have differentials. Most have open differentials, which allow the outside wheel to travel faster than the inside wheel. Open differentials have the disadvantage of sending power to the wheel with LESS grip (which is a side effect of allowing the outside wheel to spin fast... | [
"This is not accurate at all.",
"All cars have differentials. Most have open differentials, which allow the outside wheel to travel faster than the inside wheel. Open differentials have the disadvantage of sending power to the wheel with LESS grip (which is a side effect of allowing the outside wheel to spin fast... | [
"This is due to the axle setup on the FJ Cruiser, which uses an open differential with ATRAC to provide traction to tires on the ground.",
"On an open differential, the car will transfer the most torque to the wheel that experiences the least resistance. This is disadvantageous for a car like an FJ Cruiser that i... |
[
"Why aren't we using hydrogen instead of fossil fuels?"
] | [
false
] | It's my understanding that hydrogen can be produced by electrolysis using sea water. Why aren't we using solar panels, wind, whatever green energy is available to start mass producing hydrogen? It just seems to me that hydrogen is the best energy storage system out there. Clean and green. I understand there are some hurdles, such as transportation requires putting it under pressure, but we do that with natural gas anyway... doesn't seem like a deal-breaker. I want to thank everyone here for their input. I've read every reply, and believe it or not you've all given me of material to ponder and think about. I've already started watching TED talks about energy and batteries, lol! Special shoutout to and for your engaging, thought-provoking replies. Thank you all :) | [
"You touched on a few of the main problems. ",
"It's not an energy source, it's an energy storage medium and competes with batteries more than with fossil fuels ",
"It has a very low energy density and must be compressed to extreme pressures to get a decent amount into a reasonable volume. This takes a lot of e... | [
"Regards point 2 - to add to the fun, hydrogen is a slipperly little bugger and won't stay in the tank long - the small size of the molecule mean that it can make it's way through seals, or, iirc, tank walls, more easily than just about anything else."
] | [
"The third issue is that Hydrogen causes a lot of metals to become brittle (Hydrogen Embrittlement). Not what you really want in a pressure vessel."
] |
[
"Is there a way to accurately tell how much pain someone is in?"
] | [
false
] | I know that in hospitals, the 1-10 scale is used for pain, but knowing that there are pain receptors, is it possible for there to be a definite number or percentage of pain someone is in? | [
"Ooh! I actually worked on this many years ago! ",
"At least based on the massive pile of patient records I analyzed, there were no statistically significant correlations between vitals and either patient or nurse-estimated pain levels. ",
"Someone may have done a more thorough study since then, but we never ev... | [
"This. I love objective measurements as much as the next person, but when someone tells you they're suffering, all you can do is choose whether you believe them. Also why pain must always be evaluated relative to individual baselines."
] | [
"If I remember correctly, while there are pain receptors and we can measure the significance of brain activity, the concept of pain itself is relative to the person experiencing it.",
"In other words, it scales differently for everyone. What could be painful for one person, could be considered a mild discomfort t... |
[
"Where does science stand on Time?"
] | [
false
] | null | [
"Yikes. Need to add flair! I’m very Joanna at the moment!",
"My flair..."
] | [
"Yikes. Need to add flair! I’m very Joanna at the moment!",
"My flair..."
] | [
"Yikes. Need to add flair! I’m very Joanna at the moment!",
"My flair..."
] |
[
"Prisms split white light into it's component colours, based on wavelength. Why?"
] | [
false
] | null | [
"The property of prisms that allow them to spectrally resolve light is that the glass they are composed of is dispersive. Specifically, the real component of the refractive index of glass decreases slowly as you pass through the visible spectrum towards longer wavelengths as shown ",
"here",
". Snell's law, sta... | [
"Light waves are slowed in glass because they interact with the electrons in the material. In glass the electrons have particular 'natural vibration modes', and so like moving at some frequencies more than others. So the effect that the electrons have on light changes depending on the frequency of that light, which... | [
"Light waves are slowed in glass because they interact with the electrons in the material. In glass the electrons have particular 'natural vibration modes', and so like moving at some frequencies more than others. So the effect that the electrons have on light changes depending on the frequency of that light, which... |
[
"What makes the spark mechanism in a safety lighter work?"
] | [
false
] | Have you ever taken apart one of those long safety lighters, inside there is a button with wires running to it, which generates a spark when the button's pressed down. How does this work? I've searched for this before, but I've never found out how it actually works. I couldn't find a picture of what I'm talking about... am I the only one that's taken one of these apart? | [
"The spark mechanism contains a piezo-electric crystal. This is a material that builds up an electric charge when pressure is applied. You pressing the button provides the pressure, and the wires direct the spark to the fuel source.",
"Further reading;",
"piezo-ignition",
"video explanation"
] | [
"It's not effectively a battery, so you're phrasing the question incorrectly. The crystal doesn't really \"wear out\" , but it could break (shatter or something) or the mechanical parts could fail which would result in the lighter or ignition failing."
] | [
"It's not effectively a battery, so you're phrasing the question incorrectly. The crystal doesn't really \"wear out\" , but it could break (shatter or something) or the mechanical parts could fail which would result in the lighter or ignition failing."
] |
[
"How exactly does fluticasone nasal spray work?"
] | [
false
] | The stuff immediately makes my allergy symptoms go away. I know it’s a corticosteroid but I can’t find an actual breakdown of what it’s doing once inhaled. | [
"From the package insert:",
"Fluticasone propionate is a synthetic trifluorinated corticosteroid with anti-inflammatory activity. Fluticasone propionate has been shown in vitro to exhibit a binding affinity for the human glucocorticoid receptor that is 18 times that of dexamethasone, almost twice that of beclomet... | [
"Well its a great starting off point. It's probably not the most cutting edge or in depth info you can get, but its well tested. "
] | [
"Thanks friend; guess I should have held onto that, huh? Haha "
] |
[
"Is it true that an albatross is able to fly for 5 years without landing?"
] | [
false
] | [deleted] | [
"That is truly amazing. I can't even fly while I'm awake.",
"Piggybacking on the original question, can birds go for an extremely long time without eating/drinking? ",
"Edit: typo thanks IamaLlamaAma"
] | [
"I guess that's a typo but a funny one. Sleeping while awake would be quite exceptional."
] | [
"According to this ",
"article",
", Albatross is able to sleep while it flies by locking the shoulders."
] |
[
"What does the claim that our Universe is a hologram mean?"
] | [
false
] | I was watching a "Through The Wormhole with Morgan Freeman" episode in which they talk about how our reality is a holographic projection from the edges of the Universe. There's also a book I have yet to finish, called "The Holographic Universe" by Michael Talbot; the book mentions Karl Pribram and David Bohm, and their ideas are touched upon . What does this mean, and why is this important? | [
"It is a very rough description of something called the holographic principle, you shouldn't take it too seriously.",
"Basically, the holographic principle states that sometimes physics in some space can be described by a theory that lives in the boundary of that space. For example, the entropy of a black hole ... | [
"Ok, basically the way it works is that we have two different theories that yield the same physics. So any question you might have about the one theory could in principle be answered by a calculation in the other theory.",
"In this particular case the two theories are string theory or supergravity defined on \"an... | [
"I didn't mean to put you on the defensive - I'm just saying that using acronyms makes it somewhat harder to research the terms."
] |
[
"I'm looking out my window at a half-orange, half-green tree at the moment. Why isn't the entire tree orange?"
] | [
false
] | The tree's leaves are split down the middle in color. South side is orange while the north side is green. Why does this happen? Is it sunlight? Winds? Temperature on one side? | [
"Pictures might help here.",
"edit: Not trying to be facetious, I'm serious. Take a picture and post it up. Do you mean the leaves themselves are split in color, or the entire tree itself is split in half by color?"
] | [
"The tree's leaves are split down the middle in color."
] | [
"My apologies, man. ",
"Here's an example.",
"Half the tree has the red-orange thing happening with its leaves and the other half is still green foliage from summer. "
] |
[
"Can't the Japanese just drop some concrete on the reactor like it was done on Chernobyl?"
] | [
false
] | The macho (and probably dumb solution): "Let's just drop a ****load of concrete on this baby and call it a day?" | [
"Well you know, concrete will melt too, and if they haven't sufficiently cooled the core down, it will just melt. Secondly, the core is still inside the primary containment. The Soviet RBMK reactors like in Chernobyl are built completely different. The limited containment that was at Chernobyl was destroyed during ... | [
"No, they've been pumping seawater into them which writes them off completely apparently. The main reason is probably to do with getting it under control first - they might seal them off in this way eventually."
] | [
"Not to be too much of a debbie downer, but the whole concrete phase of Chernobyl happened ",
" the entire reactor had exploded in a violent fashion.",
"By the time the fire fighters were on scene at chernobyl, there was no reaction left, nothing really melting down. Just fires and smoldering wreckage. ",
"Th... |
[
"Does the size of boobs increase the probability of breast cancer?"
] | [
false
] | The last year around December, my Mom went to do some exams about breast cancer (everything went ok), she told me that she had to put her boobs in a machine, then the machine squeezed her boobs a little and a big needle pierce her and left inside a titanium chip or something like that. When I imagined this I thought: "ok, with medium and big boobs they can do this, but what if the woman has small boobs or practically no boobs at all?". Then I remembered that any picture of a woman that got affected by breast cancer and survived always has medium/big boobs and I never heard/saw of a woman with small boobs survive cancer. This may sound stupid, but I'm truly curious about this | [
"If they used the titanium clip then It’s likely she had a biopsy. This means they basically removed a small amount of her breast tissue (if this was the case you probably had to wait for lab results?). As a side note the titanium clip is almost certainly used as a marker. If the sample turned out to require surgic... | [
"Most breast cancer are carcinomas, which means they start in epithelial cells. Fat cells are called adopocytes.",
"Breast cancer is not \"the mutation of fat cells\"."
] | [
"Most breast cancer are carcinomas, which means they start in epithelial cells. Fat cells are called adopocytes.",
"Breast cancer is not \"the mutation of fat cells\"."
] |
[
"How do mirrors reflect light from a quantum perspective?"
] | [
false
] | In particular, if a photon hits a flat mirror, it is reflected at the same angle, correct? If photons are absorbed then re emitted by the mirror, how is the angle preserved? Also, is it reflected by the surface only or also by atoms deeper inside? | [
"Here is a nice explanation",
" from ",
"r/askscience",
".",
"tl;dr:\nFrom a particle perspective, we add up all of the possible paths the photon can take, and they almost all cancel out, leaving only the angle that obeys the law of reflection.",
"From a wave perspective, the surface acts like a ",
"dif... | [
"Everything is ultimately quantum in Nature, so it's quite accurate as far as we know. There's no macroscopic scale in which quantum physics stops applying.",
"In fact, good ol' macroscopic classical physics is founded on a stationary action principle (Lagrangian/Hamiltonian mechanics), which is taken as sort of ... | [
"That explanation makes it sound like all of reality is one giant interferometer. How accurate is that statement?"
] |
[
"If someone licked the inside of a dirty toilet how sick would you get? Asking for a friend."
] | [
false
] | null | [
"We can't comment on personal anecdotes / isolated incidents without resorting to speculation which we try to avoid."
] | [
"Let’s speculate. I’m fine with that. I know this isn’t webmd "
] | [
"We don't allow such posts on this sub. Try another. You can use ",
"/r/findareddit",
" for help in finding an appropriate sub."
] |
[
"Is there a scientific reason for hiccups?"
] | [
false
] | I just had the hiccups for about 15 minutes and I cannot think of one reason as to why this would be vital for human survival. | [
"The process that causes hiccups is the same that allows tad poles and lung fish to be able to breathe both in air and water. So there is a chance it is a vestigial character left over from evolution"
] | [
"Do you know of any studies looking into this characteristic of hiccups?"
] | [
"Going on right now? Not that I know of, bu there was an article is Science Magazine or Scientific American that was talking about it. I'll try and dig through the ones and work and try to find it. Might be available online somewhere",
"EDIT: Here is a post from Scientific American, though it isn't a study. ",
... |
[
"Is Muscle Atrophy in Zero-G caused by the lack of gravity, or the lack of activity while in gravity?"
] | [
false
] | null | [
"It's from the lack of gravity mainly, but they two ideas almost go hand in hand: the presence of gravity requires more force from a muscle to move a limb, and thus, in zero gravity, when a muscle does not have to work as hard to move a limb, it atrophies."
] | [
"Yes. Also, in null gravity your slow-twitch oxidative muscle fibers convert to fast-twitch glycolytic. One speculation as to why this happens is that weight bearing muscles are virtually all slow-twitch (high fatigue threshold). This is important because we don't want to get tired just stand or sitting up. Now whe... | [
"To rephrase my question; does the pull of gravity alone fight muscle atrophy, or does one need to move for gravity to be effective?"
] |
[
"How fast do plants make oxygen?"
] | [
false
] | Sig Factors are probably surface area, environmental conditions effecting respiratory rate but how many moles of oxygen does a typical plant cell produce in a day? what about a bkade of grass? A 4 ft plant? | [
"This is a very (very) common misconception. I mean i've seen several lecturers make this slip. The O2 doesn't come from CO2 with the carbon ripped off. The oxygen actually comes from water - the plant uses light to split a molecule of H2O (called hydrolysis) to release hydrogen ions and oxygen - the oxygen diffuse... | [
"This is a copypaste of what I have written to somebody else. I hope it might help you:",
"Let me calculate this for you:",
"Some papers say a beech tree absorbs about 6kg of CO2 per day.",
"The mass of our substance divided by its molar mass gives us the amount of particles:",
"6000g/(44.01g/mol)=n=136.330... | [
"Just going to point out that converting into volumes is an unnecessary step. From the equation you can see that there is a 1:1 ratio of carbon dioxide taken and oxygen produced. So there are 136.33 mol of oxygen produced which you can multiply that by the molar mass to get your 4.36 kg of oxygen."
] |
[
"If you lay or sit in a position that causes a limb to \"go to sleep,\" would you then be able to amputate that limb painlessly?"
] | [
false
] | null | [
"Extremely unlikely. Parasthesia is usually caused by reduced circulation; reducing circulation enough to inhibit nerve responses would cause both tissue damage and significant pain of its own accord. "
] | [
"To add to this question, when a limb wakes up (like an arm or hand), what is actually happening when I feel the electric pins and needle sensation that can come on very strongly as the limb wakes up?"
] | [
"If you're looking to amputate your own limbs please do consider seeking a medical professional, if not I would suggest any cryogenic fluid, such as liquid nitrogen."
] |
[
"Do wasps have a positive net effect on polination?"
] | [
false
] | [deleted] | [
"Tl:dr: Yes, of course they do.",
"Wasps perform numerous important ecological functions and reducing their numbers is an awful idea. \"Honeybees\" are technically a domesticated animal, and in the US, are actually considered to be a ",
"problem",
" when they become feral. There are thousands of plant species... | [
"In the U.S. except in rare occasions wasps are not a significant killer of honey bee. Those rare occasions are typically late fall when everything has stopped blooming and certain wasps, yellow jackets in the southern U.S., attempt to rob hives. They can in that circumstance kill a lot of bees even destroy a hive... | [
"My garden is almost exclusively pollinated by wasps. I value them more than bees. ",
"The bee keeper is mad becsue HE loses money when a wasp comes and kills the invasive (honey bee imports) bees. It has nothing to do with protecting bees, that's his lively hood. He wants to kill wasps who are a major player in... |
[
"What are some evolutionary explanations for homosexuality?"
] | [
false
] | [deleted] | [
"Well, if I may take a stab at clarifying your question, I think what you're really trying to ask is \"why hasn't natural selection removed a trait that seems to make animals not want to reproduce?\"",
"In order for a trait to be subject to natural selection in the first place, there need to be different versions... | [
"Great answer, very well put.\nMy "
] | [
"This needs to be FAQd cause its asked every week"
] |
[
"If I stopped wearing my glasses, would my eyesight revert back to normal? If I had never gotten glasses as a kid, would my eyesight be fine as an adult?"
] | [
false
] | null | [
"No. Although your eyeball shape does continue to change as you age, so it's possible that a mild myopia or hyperopia will correct itself... but it's not ",
" you didn't wear glasses."
] | [
"So then is there any way your vision could be made worse by glasses?"
] | [
"I'm not aware of any evidence supporting this. Although if you wear the incorrect prescription, it can give you headaches. "
] |
[
"Why doesn't mold start growing on food immediately?"
] | [
false
] | Why does it take 1-2 weeks sometimes for bread to start to mold? Or several days for food to start molding in my fridge? What is the mold "waiting" for? | [
"It does. The mould you see is typically the fruiting body and spores. They are darker to protect them from damage due to UV light The mould has been growing for quite some time before you start to see the effects visually. Prior to that it's simply not visible to your eye the same way bacteria is not visible on yo... | [
"It really isn't a bad thing though, just a common misconception that really ought to be corrected. ",
"We tend to like to pretend that our world is clean and sterile when it most certainly is not. The fault is not with the world for being what it is but with us for pretending it is something else. A little mold ... | [
"It really isn't a bad thing though, just a common misconception that really ought to be corrected. ",
"We tend to like to pretend that our world is clean and sterile when it most certainly is not. The fault is not with the world for being what it is but with us for pretending it is something else. A little mold ... |
[
"How do electrical signals instigate contraction in muscles?"
] | [
false
] | What is the mechanism behind the contraction of voluntary muscles due to electrical signals being sent from the brain? Does the same mechanism apply to involuntary (smooth, cardiac) muscles? | [
"A signal travels down the membrane of a muscle cell until it reaches membrane-bound calcium channels, which are stimulated by the electrical signal to transport calcium into the cell. The calcium further stimulates ryanodine receptors on the sacroplasmic reticulum to causes release of even more calcium ions into t... | [
"It's all about ATP binding. ",
"Here",
" is a link that explains the role of ATP and calcium ions in muscle contraction and explains how the nervous system is responsible for ATP actuation."
] | [
"the motor neuron descends directly from your brain in the case of your fingers",
"Are you saying there are only Upper Motor Neurons supplying the radial, median and ulnar nerves? I've never heard of that, could you explain please?"
] |
[
"Why don't they launch space bound rockets out of tube like bullets from a barrel of a gun?"
] | [
false
] | null | [
"A gun barrel serves as a means to influence control over direction of a bullet's travel ( though it also keeps the explosive forces concentrated behind the projectile)",
"Because the rocket is capable of being steered and carries it's own gunpowder, firing it through a tube is simply not required."
] | [
"Because it would not have any benefit.",
"The difference is that a bullet is pushed by an explosion next to it and pushed out by the expansion. A rocket is pushing itself away by pushing out the exhaust of the burned fuel.",
"So you don't need to direct the push, since it is inside the rocket anyways."
] | [
"If you actually could impart enough energy into the space bound rocket to reach orbit, depending on the length of the tube you would have to impart such strong g forces on it that you would kill anyone inside and likely also destroy any sensitive equipment.",
"So it needs to be a slow and steady push, with a gra... |
[
"Does the hydrophobicity of an objects surface affect the bouyancy of the object?"
] | [
false
] | Will one of two objects break the surface tension of water quicker if the only difference between them is their surface texture? Will one of the two sink faster afterwards? | [
"No. hydrophobicity doesn't have any effect at the macro (i.e. large) scale. Years ago there was a youtube video that showed people running on water because they wore waterproof shoes. It was a total hoax, but for months afterwards people were asking \"what if's\" about hydrophobic materials. ",
"At insect size s... | [
"What if a speed boat had rainex? Could gliding easier provide more lift with increased speed and aerodynamics? "
] | [
"The boat still has to physically push the water out of the way to move forward. It’s the water’s inertia more than surface friction that slows the boat down."
] |
[
"Does modern firefighting equipment have preventive measures for extreme cold conditions?"
] | [
false
] | I was reading an article about the in NYC which was left to burn since the firefighters equipment froze during the blaze. I realize hydrant lines are pressurized, but would they still be likely to freeze under extreme conditions? | [
"In a word, yes. ",
"We have a more scientific understanding of how to prevent things from freezing today than we did in 1912. For example, on a cold day we never shut the hose off entirely once it's been charged - we'll keep the water moving. Moving water is harder to freeze. A fire on a day when the tempera... | [
"In areas where freezing is likely there are dry hydrants which don't hold water in them. The water supply is under ground and is accessed by opening a valve on the hydrant. A dry hydrant looks like what you're familiar with as a fire hydrant."
] | [
"Thats a dry barrel hydrant, a dry hydrant is actually something slightly different. The dry barrel has the valve at the main located below the frost line. Turn the nut at the top, it spins a long shaft, and opens the valve below. This shaft can and does snap from time to time. When the valve is closed, it opens d... |
[
"Does the sport you play while going through puberty affect your body type for the rest of your life?"
] | [
false
] | My brothers and I pretty much grew up the same height and weight at our respective ages through our childhood. We all played soccer pretty much everyday for years but I was the only one who ended up quitting soccer in order to wrestle around the time of puberty. Years later my brothers are both still pretty skinny and lean where as I am a bit more thick with muscle. I am wondering whether wrestling during puberty changed the way my body developed as oppose to the way it would have if i played soccer | [
"The book, \"The Sports Gene\" touches on this quite a bit. Your genetics play a the part in how these differentials occur. You may have received the gene for larger muscle growth and due to the type of training you may have received in wrestling your body may have had the ability to express that gene, more so then... | [
"While this may not apply to you and your brother, I want to point out a common fallacy that I think is relevant here. With competitive athletics, there is often the notion that the sport produces the body type that you have. Runners have small frames because they're runners, swimmers have wide shoulders because th... | [
"Unfortunately its not so simple. We currently dont have an extremely good understanding of what genes cause what results because often it is an accumulation of different genes that cause a certain result. Scientists are constantly working to understand certain genes and work out how they express themselves but thi... |
[
"What is the current scientific consensus on Genetically Modified Organism (GMOs) in our food?"
] | [
false
] | I'm currently doing a research paper on GMOs and I'm having trouble gathering a clear scientific consensus. | [
"The safety of currently used GM crops is clear.",
"US National Academies of Sciences stated: \"To date, no adverse health effects attributed to genetic engineering have been documented in the human population.\"",
"\"A 2008 review published by the Royal Society of Medicine noted that GM foods have been eaten b... | [
"Absence of evidence (in your comment) is not evidence of absence in the real world. Here are some I found with just a few minutes in Google Scholar, etc.:",
"Only one of those addresses safety, and that article is written by an author known for using misleading statistics",
"Multiple independent investigations... | [
"\"GMOs are totally safe\" ",
"Never said that.",
"I have said, that current evidence clearly supports safety.",
"But, as some of the peer reviewed links that I offer show, there is clear evidence that GMO crops are not safe based on a reasonable definition of \"safety\".",
"You haven't shown any such links... |
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