title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"What evolutionary pressures led to the differences of morphology among different human races?"
] | [
false
] | Question inspired by the Olympics. I use the term 'races' out of ignorance of a better way of classifying humans, but it seems as though people of African origin generally seem better suited for track races, people of European origin seem better suited for water sports, and people of East Asian descent seem to be bette... | [
"My guess is that most of these apparent athletic advantages have far more to do with culture than they do with race. If you observe a human behavior, and you cannot think of a reason why it's adaptive, that's oftentimes a good clue that it's not adaptive after all.",
"Consider: track sports are a big cultural ph... | [
"At least one study compared body types between whites and blacks. They found that blacks tend to have a higher center of gravity, which makes it easier to run fast, but harder to swim fast. ",
"Here",
" is an article about it. In the article they reference the study."
] | [
"Even if genetics were the deciding factor, one would have to remember that the diversity among Africans dwarfs the diversity among other ethnic groups."
] |
[
"Anti-Photon"
] | [
false
] | Just something I have been wondering. Since Photons don't have charge, while they do have an antiparticle, it is completely indistinguishable from them? Right? So would this mean, that unlike other antiparticles, the two would not annihilate each other if they came into contact? Is this correct? | [
"The photon is it's own antiparticle and ",
" of this two photons can annihilate with each-other."
] | [
"Under the usual conditions; when two photons collide, they annihilate.",
"In regular particle-antiparticle annihilation a particle and its antiparticle annihilate and produce two photons. Photon-photon annihilation is the time-reversal of this process, where two photons annihilate and produce an antiparticle/par... | [
"Pair production or creation of one electron and positron would be an example of two photons annihilating."
] |
[
"Which one is closer to the fossil records, the traditional view of evolution that it happened it gradual transitions, or the newer theory which is the punctuated equilibrium?"
] | [
false
] | null | [
"Both are consistent with the fossil record. Punctuated equilibrium is a form of gradualism. The Punctuated Equilibrium theory still allows for the incremental changes of gradualism during the \"stasis\" period of a species but states that genetic drift in large populations keeps the species relatively homogeneous.... | [
"Both are gradual, ok. I guess I wrote my question poorly.",
"\nThe traditional view is, evolution occurs in constant and steady rate. in punctuated equilibrium, it's like species stay pretty much the same until a \"punctuation\" or a big jump to evolve into a new specie occurs.",
"Okay. Which is closer to th... | [
"It depends on which fossil lineages you look at. Some lineages, like many mollusks, are pretty well characterized by gradualism. Others, like vertebrates, seem to evolve in fits and starts, with species appearing very suddenly.",
"Why might this happen? Good question. Part of this is related to the old question ... |
[
"Why am I always tired throughout the day, but energetic at night while surfing reddit until 3AM? Shouldn't I just keep getting more and more tired until I fall asleep?"
] | [
false
] | null | [
"Your circadian rhythm is controlled by melatonin levels. Elevated melatonin causes drowsiness and melatonin should decrease to undetectable levels during the day.",
"Melatonin production is suppressed by shining blue light around 460 to 480 nm onto the retina. ",
"So perhaps you are not receiving enough blu... | [
"Sunlight would be the normal thing. ",
"According to some researchers the illumination intensity that excites the circadian system has to reach up to 1000 lux striking the retina for about an hour which is easily achieved by simply walking about in sunlight when you wake up.",
"Of course this doesn't help if ... | [
"What is meant by blue light intensity? Sunlight or what"
] |
[
"Is there a confirmed link between sleep deprivation and Alzheimers?"
] | [
false
] | Are there any current work, linking sleep deprivation to Alzheimers, or at least discussing it thoroughly(based on current research) (I'm new to this subreddit) | [
"It's still soon to determine that, but yes, sleep deprivation ",
" be a risk factor for Alzheimer's: there's a molecule that's produced in the brain called beta-amyloid. People with Alzheimer's have high levels of beta-amyloid in their brains, and sleep deprivation is one of the factors that influence the format... | [
"Agreed on all points. I just wanted to post another a 2013 article that talks about sleep and it's role in clearing things like amyloid through the brain using some sort of lymphatic system (termed glymphatic system). ",
"http://www.ncbi.nlm.nih.gov/pubmed/24136970",
"Again, you're right that there is no causa... | [
"Whilst you've made no claim on the contribution of ",
" to Alzheimer's disease, I feel one should note that a large portion of literature is now pointing towards ",
" as the primary cause of neurodegeneration in Alzheimer's disease. We sectioned many wild type healthy brains and found large deposits of ",
".... |
[
"If you bombard an iron-56 with neutrons, is there a limit to how many neutrons it can gobble?"
] | [
false
] | null | [
"You sure can't get past the neutron drip line, which I think is experimentally unknown but is somewhere after Iron-74. However, the process is nearly impossible because for instance, you have to pass through nuclides like Iron-72 which has a half life of 150ns, so it would be very hard to get another neutron adde... | [
"It can keep capturing neutrons until it reaches a point where neutrons no longer remain bound to it. This is called the neutron dripline."
] | [
"These are the kinds of questions quantum computers could answer, I take it."
] |
[
"How did dyslexia manifest itself before the rise of written language?"
] | [
false
] | null | [
"Well I'd hate to just link to wikipedia, but it does list ",
"many non-writing related characteristics of dyslexia",
"."
] | [
"From the source for that line (a ",
"NY Times article",
"):",
"It has long been known that dyslexics are drawn to running their own businesses, where they can get around their weaknesses in reading and writing and play on their strengths. ",
"\"It has long been known\" is often akin to hand-waving, but the... | [
"Dyslexia doesn't just affect written language. As a sufferer or it there are other symptoms that affect day to day life. Remembering names is a big one. Knowing directions and drawing dirt maps could have been challenging."
] |
[
"How robust is the paper from Steven Quay about the potential lab-based origin for Sars-CoV2, does it make a compelling argument and if so/not so, why?"
] | [
false
] | null | [
"So given that your background is virology/immunology, can you at least tell me if this guy Steven Quay is respected, considered a crank or what?"
] | [
"Crank"
] | [
"r/askscience",
" is not an appropriate place for ridiculous conspiracy theories."
] |
[
"I am sitting in a boat in a lake of superfluid helium. Can I use oars to propel myself? What about propeller? Also, am I in danger of sinking?"
] | [
false
] | null | [
"Assuming you mean liquid helium-4 at a temperature below the super fluid transition temperature, yes you are in danger of sinking. The liquid helium will creep up the side of the boat and the fill the inside. ",
"Propelling yourself would be hard as helium has essentially zero viscosity. However if you move t... | [
"The superfluid viscosity is very low, but not zero. Its possible to measure a finite viscosity in shear mode flow at all finite temperatures. There are contributions due to elementary excitations in the fluid, in the Landeau two-fluid model these excitations are referred to as 'normal' state fluid, whose bulk frac... | [
"Helium-4 is a boson (has an integer nuclear spin) because it is made up of an even number of half-integer spin protons and neutrons. This means that it follows Bose-Einstein statistics that allow for the formation of the superfluid, which is Bose-Einstein condensate-like.",
"Helium-3 is a fermion (has a half-int... |
[
"How does a bolt of lightning cause a current in an electric appliance even when the lightning does not strike the device?"
] | [
false
] | I'm also curious to know how a surge protector protects devices from the bolt. | [
"Lightning affects devices if it strikes a power line that supplies electricity to that device. That's how it usually happens. A surge protector detects an increase in current and cuts off the power to whatever is plugged in"
] | [
"If a bolt strikes a power line that is connected to that device, there will be a very large and very rapid change in potential on the line. This causes a whole lot of charge to try to move. At its most basic, a surge protector reacts to this rapid change and breaks the circuit before the majority of the charge has... | [
"Unless the $3 \"surge protector\" you got at walmart is so shittly made it shorts and fries your gear anyways [been there done that]."
] |
[
"Why do people with down syndrome look similar to each other?"
] | [
false
] | Growing up, whenever I saw someone in my middle school or high school, whenever I saw someone with down syndrome I thought that they were in the same family and that it was a hereditary disease. I've come to realize that's not the case, when I was in college. So what is it about down syndrome that makes the person who ... | [
"This is an evo-devo question + morphometrics question. I'm not great w/ evo devo, but I think I'm good enough to be able to give a coherent answer.",
"Developmentally, a whole host of genes work to define how your body grows. It turns out - when you average those genes together, based on how common they are in o... | [
"No, OP is asking in ",
"/r/askscience",
" not ",
"/r/explainlikeimfive/",
"Although the link you provided is somewhat informative, ELIF is a different forum with a different readership, and more importantly, much different posting rules. It was perfectly valid for the OP to post here expecting a scientific... | [
"I think there's another factor at play - how we distinguish faces.",
"A couple of studies have shown that babies can distinguish between different monkey faces incredibly well, but adults can not. After seeing potentially millions of humans but a tiny number of monkeys through our development stages, we hone our... |
[
"For beta decay: During positron emission a proton becomes a neutron and emits a positron (and neutrino). During electron emission a neutron becomes a proton, emitting an electron (and antineutrino). How is it possible that they can convert back and forth by continuously losing particles?"
] | [
false
] | I've had this question for a while. It doesn't make sense that they can convert into each other by losing particles each time. Can someone please explain. | [
"A proton is made of 2 up quarks and 1 down quark. A neutron is 2 down quarks and 1 up quark.",
"In beta- decay, an up quark converts to a down quark, and emits a W- boson. This boson decays to an electron and an antineutrino.",
"In beta+ decay, a down quark converts to an up quark and emits a W+ boson, which... | [
"The W boson in neutron decay is a virtual particle: it's momentum and energy don't satisfy E",
"=m0",
"+p",
", as all real particles should (some folks call that \"off the mass shell\", as if we instead make mass the free parameter, the mass we would anticipate measuring doesn't match the mass of the W-boson... | [
"In neither process do the protons or neutrons loose any particles. The electron/positron is created during the decay process and there is no sense in which it was inside the proton/neutron to begin with. Both forms of beta decay transform a parent nucleus into a product nucleus with less energy than the parent. Th... |
[
"I just made some delicious instant chocolate pudding. How does it work?"
] | [
false
] | I'm talking about U.S.'s pudding, the custard-like dessert ( ). It starts as a powder. Add cold milk and it gets that gelatin consistency. What's going on? Is it a dehydrated molecule that gets rehydrated? What are the delicious chemistry specifics. | [
"Alright, on the instant version, see where it says 'Modified Food Starch'? In this case, the modification is a process known as ",
", where the starch is partially cooked using steam and then rapidly dried. This means that the starch does not need to be heated to reach the thickening point, giving you delicious ... | [
"No idea what that stuff is, but looking at the ingredients list, with cornflour / starch being the main ingredients, I assume it's to do with ",
"http://en.wikipedia.org/wiki/Starch_gelatinization",
".",
"Corn flour (corn starch in the US) is a thickening agent. Basically, to quote wikipedia: \"As the starch... | [
"Pudding is not gelatin.",
"Ingredients in instant pudding:",
" Sugar, Modified Food Starch, Contains less than 2% of Natural and Artificial Flavor, Salt, Disodium Phosphate and Tetrasodium Pyrophosphate (For Thickening), Mono- and Diglycerides (Prevent Foaming), Artificial Color, Yellow 5, Yellow 6, Bha (Prese... |
[
"What would happen if we built a giant smokestack that was tall enough to be in space, and started burning a bunch of stuff on the ground?"
] | [
false
] | Might be a silly question. Still curious just the same. What would happen to the smoke/pollution if we started burning a bunch of stuff here on earth but had all of the nastiness float up through a giant smokestack some distance off into space? Would it dissipate or just hang out there, ready to poison us at some later... | [
"Assuming you can build the stack in a way that it's stable. And then assuming that you could find a way to make sure everything goes all the way to the top and you could actually eject stuff into space...",
"Earth's gravity would just pull all that crap back into the upper atmosphere."
] | [
"The official answer is that the risk of the rocket launch failing and exploding that \"nastiness\" (which, I assume, is nuclear waste, some pretty nasty stuff) all over the countryside."
] | [
"so you'd have to build this huge hollow tube from the earth's surface out past the last layer of our atmosphere. Then you'd have to accelerate the smoke using a mechanical method past the escape velocity of the earth's gravitational pull. If you could do those things, chances are the smoke would dissipate, and b... |
[
"Why did hominidae lose their tails in the evolutionary process?"
] | [
false
] | null | [
"To grow a tail takes energy. If a species that once had a tail stopped using the tail, it would be advantageous to not grow that tail and use that energy to do something else. ",
"This is called 'Reductive evolution'.",
"Of course, it's not as simple as a monkey having a kid, which ends up not having a tail. E... | [
"Just a follow up question, would having a tail affect our bipedal efficiency?"
] | [
"Tails were mostly used fr balance by creatures which require it. Apes did not."
] |
[
"Is there a temperature where water will never freeze or evaporate?"
] | [
false
] | To expand on that, say you had a ring of water left over on a table after a cup was sitting there for a period of time. In any 'normal' condition the water will evaporate off the table, and if it were especially cold it would freeze. Is there a situation where the water will remain in liquid state indefinitely due to i... | [
"It boils at 100 degrees Celsius it evaporates at much less. Thats how we get a water cycle on earth. ",
"Edit: at sea level , it can boil at lower temperature at higher altitudes"
] | [
"It boils at 100 degrees Celsius it evaporates at much less. Thats how we get a water cycle on earth. ",
"Edit: at sea level , it can boil at lower temperature at higher altitudes"
] | [
"Take an enclosed volume at 100% relative humidity, apply higher pressure and cool the air and the puddle would conceivably never evaporate. In fact, under those conditions additional condensation would form as the water vapor is 'squeezed out of the air', so to speak. "
] |
[
"Why do seismic waves (P waves and S waves) travel at curves through the Earth?"
] | [
false
] | I know how they refract when they reach structure boundaries because of the different density of the structures e.g. crust to mantle, but don't understand why they travel at curves through those structures. | [
"It's because refraction does not have to be an instantaneous process.",
"If the density changes suddenly, the wave will indeed just change the direction of its propagation.",
"But if the density changes gradually, the wave will follow a curved path. Think of it as the same change in direction, but over a certa... | [
"Because the waves travel faster in denser mediums, and even within the layers themselves there is a density gradient. I visualise it as the 'outside' (deeper) part of the wave travels quicker and the 'inner' part of the wave travels slightly slower, resulting in a curve."
] | [
"It's because even within the different layers of the Earth, like the mantle, there are small variations in temperature, density, seismic velocity and so on. These variations add up over distances so waves will continuously refract as they pass through areas with (slightly) different seismic velocities. Eventuall... |
[
"If a space ship is going 99% speed of light time is slower for them according to the earth (I think) but if the space ship is out reference point then the Earth is going 99% the speed of light. So wouldn't time be going slower on earth in relation to the ship?"
] | [
false
] | So 1 earth hour is only .5 hours on the ship (I am fully making numbers up here) because the ship is moving 99% the speed of light relative to the earth. But if you choose the ship as a reference point then the earth is the one moving so that would mean (as I understand) that 1 hour on the ship would only be .5 hours o... | [
"It is important to take into account the difference between the very nature of the two observers.",
"If you take the observer in the spaceship, what they see is the earth and all of space moving away from them, as if their ship is standing still. This means that we must also consider spacial contraction. This ... | [
"Someone standing on the Earth will observe that time is moving more slowly on the ship, likewise someone on the ship will observe time moving more slowly on the Earth. This is just what is observed however, in reality since it is only the ship that has undergone acceleration, it is only the ship that will be movin... | [
"I think I can explain some of the downvotes. Part of your answer is wrong. It is completely untrue that \"since it is only the ship that has undergone acceleration, it is only the ship that will be moving more slowly through time\". If this WERE true, then you have established sufficient criteria for a preferre... |
[
"If nuclear testing increased the Carbon-14 ratio of the atmosphere, would a comet or asteroid impact do the same?"
] | [
false
] | null | [
"No. The production of C14 was a direct result of interaction of energetic fission products - ",
"specifically neutrons",
". Those require nuclear events.",
"A meteorite or comet collision does not do this (it is simply a high energy collision), and does not produce the neutrons necessary to form C14 in the a... | [
"Anything that can provide a neutron bombardment. Fusion or fission are basically the only two natural processes. "
] | [
"Thank you!",
"Can any phenomenon other than nuclear fission produce excess C14?"
] |
[
"Why isn't the sky violet?"
] | [
false
] | [deleted] | [
"Edit: ",
"Better answer in the thread the Rupert's search link leads to"
] | [
"Sunlight interacting with the Earth's atmosphere makes the sky blue. In outer space the astronauts see blackness because outer space has no atmosphere. \nSunlight consists of light waves of varying wavelengths, each of which is seen as a different color. The minute particles of matter and molecules of air in the a... | [
"While it is true that a large portion of the sun's emmission spectrum is in the red-yellow band, and this can be detected using a ",
"spectrometer",
", the sun ",
" white to us in outer space because the human eye didn't evolve to differentiate between true white and the color of the sun."
] |
[
"Why is it that when I look in a mirror when I'm wearing glasses my eyes appear bigger but on video/photos they're smaller when I'm wearing the same pair. I have bad eyesight, full disclosure."
] | [
false
] | null | [
"because you are looking through the lens twice when looking at a mirror, and only once when seen directly"
] | [
"This...changes everything."
] | [
"Also, ever tried looking down a telescope through the wrong end? Same phenomenon."
] |
[
"Is it possible to create a human oocyte from male genetics to be fertilized by sperm?"
] | [
false
] | Seems like an odd question... Don't judge me. I'm just curious if there is enough genetic material in biological male DNA to create an egg, fertilize it, and have a surrogate carry. | [
"Yes – in fact, this is my PhD research project!",
"The basic idea is to convert pluripotent stem cells to egg cells. XY oogonia will undergo meiosis to form oocytes. Half of those will be non-viable since they'll lack an X chromosome, but half should be viable oocytes.",
"I'd be happy to answer any questions y... | [
"theoretically you can take a sperm (that have to be an X carrying sperm) and pluck the nucleus from it and inject it into an egg that had its own genetics removed, Then fertilize it.",
"It won’t be a simple under taking however, even though the genetic material exist, it has be activated a certain way, and that ... | [
"Cool! How do you deal with epigenetics and imprinting effects? I’m thinking of things like Angelman and Prader-Willi syndromes. Does the imprinting just reset?"
] |
[
"Do we already have an enormous database of naive B cells in our body, before even meeting the specific antigen?"
] | [
false
] | I can't wrap my head around how our body will make an antibody that fits the antigen during the first encounter. The VDJ recombinant genes are firstly random, and also they do not know how the antigen looks | [
"Yes, we do have a huge inventory of naive B cells normally present in our body. ",
"Antibody (and T cell receptor) development is something that seems really alien to our human eyes - it seems so wasteful and irrationally designed, and yet the end product is so efficient and elegant. The overall approach is simp... | [
"In short yes,",
"This is because B-cells develop their B-cell receptor through VDJ recombination as pre-B cells prior to B-cell maturation. At maturation the B-cell leaves the bonemarrow to travel the body, and at this stage the B-cell is considered naive as it has not met a bindable antigen.",
"During the fir... | [
"I understand that rearrangements and shuffling of gene segments can result in a huge number and variety of B-cell receptors. I always wondered about how a finite number of genes could generate such a huge diversity of proteins and I got my answer, but where I'm not clear is how the immune system, upon infection wi... |
[
"How do we know for sure that red-shift in distant galaxies / stars is because they are moving away and not because of some other unknown effect on light traveling for insanely long times / distances?"
] | [
false
] | I know that there is probably something very basic that I am missing but this question keeps coming back into my head after years of thinking about it, and I can't find anything online that explains it (from a google search anyway). I understand how the doppler effect works, and have no doubt that stars moving away WOU... | [
"This is basically the old 'Tired Light' theory, which was an earlier challenger to the explanation of expanding space:\n",
"https://en.wikipedia.org/wiki/Tired_light",
"Suffice it to say that a century of astronomical observations highly disfavor any model like this, but there are some good explicit examples i... | [
"This completely answers my question. Thank you!"
] | [
"The analogy is insufficient as our atmosphere refracts light (bending) and different colours of light are refracted through different angles due to their different wavelengths, which is why we get a rainbow. Also photons of light will be absorbed by atoms/molecules in the atmosphere which is why objects appear fai... |
[
"Would it be possible for an animal to have a mutation that would allow it to breed with humans?"
] | [
false
] | [deleted] | [
"No. Even primates have a different number of chromosomes."
] | [
"Then again, so do those with downs."
] | [
"Many individuals with Down Syndrome are either sterile or have significantly reduced fertility."
] |
[
"Can the Hubble telescope take a picture of the Webb telescope?"
] | [
false
] | Do their relative positions let them see each other? | [
"Hubble is in Low Earth Orbit, and spins around the Earth about once every hour and a half. So it quickly gets a view of almost everywhere in the sky.",
"But JWST is too small to be seen as more than a dot, even by Hubble. The sunshield is 22 metres across, but it's 1.5 million km away. This gives it an apparent ... | [
"The blur is the \"point-spread function\", which depends on the optics of Hubble rather than the shape of the object. If you cancel it out, it turns a blurring spot into a sharp point, but doesn't give you any shape information."
] | [
"Yes, although that would still be effectively a single pixel. If you want a 4 pixel wide image, which is still extremely low resolution, then it'd need to be about 60 times larger.",
"But yeah, HST has high resolution, and JWST isn't that far away on an astronomical scale, and is pretty big as far as artificial ... |
[
"[Biology] Why can't we use transgenic polyDNAviruses from parasitoid wasps to introduce beneficial metabolites straight into our own DNA?"
] | [
false
] | If we can identify the genes responsible for the production of beneficial proteins and the like why can't we take the polyDNAvirus venom from parasitic wasps and splice them in to create a vaccine that would allow our bodies to produce cures for stuff like Parkinsons that are caused by running out of them? | [
"These are viruses that originally infected one insect and adapted to infect a different insect so that would be a tricky part as far as using it for humans is concerned. The basic premise of what you are saying is \"gene therapy\" and there are people working on adapting various viruses for that. "
] | [
"We are trying - this technique is known as gene therapy, and has made great strides recently (as in within the past month or so).",
"Viruses are stripped of their DNA, and a new piece is added, to be inserted in specific tissue type. Adenoviruses are more common, as their DNA can hang out in the nucleus without... | [
"Gene delivery is a very real thing we're working on. I think what you're talking about is a retrovirus; a type of virus that basically rewrites our DNA with its own. ",
"The most popularly known kind of retrovirus is HIV, the AIDS virus. While retroviruses like HIV retool our DNA for its own nefarious purposes, ... |
[
"How do I get melted plastic off my cast iron?"
] | [
false
] | null | [
"If it's just this are of the pan, take some steel wool to it, or some mechanism to grind off the metal, like metal polish. It's probably going to be easier to remove mechanically now that you've baked it on that chemically. "
] | [
"How localized is this plastic residue? All over the inside of this skillet in a thin layer, or in a single glob?"
] | [
"Get the pan really cold. The plastic might be able to peel off then.",
"Acetone probably won't much but melt the plastic further. ",
"I would go nuts with a wire brush on it. Then reseason the pan. "
] |
[
"How many fundamental constants are there?"
] | [
false
] | I am pretty sure the speed of light is a constant (Or maybe it's just equal to 1 and not considered a constant?) But what are the fundamental constants relevant to our universe that can't be derived by an equation but simply had to be measured? | [
"One of the rare questions that can be simply answered with a link to an article: ",
"http://math.ucr.edu/home/baez/constants.html",
"tl;dr: 26"
] | [
"you can derive the number of constants from all the other constants."
] | [
"Not to be rude or whatever, but this isn't the sort of thing that requires \"proof.\" It's just definition. It's customary in some branches of physics to convert all physical quantities to units of length before doing any calculation. When you do, all physical quantities end up being expressed either as units of l... |
[
"Why are there two formulas for half-life?"
] | [
false
] | null | [
"What formulas are you referring to?"
] | [
"Remaining Sample = me",
"\nand\nRemaining Sample = m÷2",
"Where\nm = initial sample size,\ne = the natural constant of e,\nr = (ln2)/h,\nh = length of one half-life (in years),\nt = elapsed time since beginning of decay (in years)"
] | [
"These equations are equivalent."
] |
[
"Why was earth bombarded with meteorites so much throughout its history, but not now?"
] | [
false
] | [deleted] | [
"During the ",
"late heavy bombardment",
" the Earth was pummeled with meteors much more often than it is now. It's unknown exactly why the heavy bombardment happened, but it may have to do with changing orbital patterns of the gas giants. The late heavy bombardment ended about 3.8 billion years ago.",
"In ... | [
"Great answer, thanks. Kudos for the sources also :-)"
] | [
"Additionally, Jupiter does a great job of hoovering most incoming debris from the Oort Cloud."
] |
[
"Former creationist here: with so few pre-human fossils over millions of years, how do we extrapolate data of past human evolution?"
] | [
false
] | 21 years old and for the first time I'm getting a science education at my local community college. But I'm just confused at this area of human evolution. We have a small amount of our ancestor's fossils, and usually they're spread across millennia and vast geographic distances, how does science form connections between... | [
"Actually there are more than just a few fossils. Here's ",
"a list of just a few of the thousands of them",
". I remember seeing a video about forensic paleontology once, but of course I can't find a link to it. It was pretty interesting, the idea is that bones can only grow and wear in certain ways, and the w... | [
"Hi, I am actually a grad student studying paleoanthropology, and I'm happy to answer any questions that you might have about human evolution. I mutatron answer some of the basics, and I just wanted to chime in with some more details. ",
"Depending on who you ask, there are either a lot of human fossils, or not v... | [
"It also helps that many of these fossils are located in the East African Rift system, which helps us document the age of the fossils. Lots of sediment is available to bury bones before they're destroyed by the elements because of the deep valleys created by the rifting. Volcanic eruptions in the area produce ash a... |
[
"What are some dyes that stain human skin, and how do they work?"
] | [
false
] | null | [
"We don't offer advice or recommend products on this sub."
] | [
"what if I rephrase the question what dyes penetrate the cell wall or something? Where can I ask"
] | [
"You could try some bio related sub. You could try posting to ",
"/r/findasubreddit",
" to see if someone can suggest a specific sub"
] |
[
"Why is carbon so rare compared to oxygen in the inner solar system? Why don't we have tons of carbide minerals on earth?"
] | [
false
] | null | [
"Largely because of the quantities of the elements in the universe. The Milky Way, which seems to be a generally good indicator of the broader universe, has much more oxygen than carbon. 10,400 PPM are oxygen, while only 4,600 are carbon.",
"Source: Croswell, Ken (February 1996). Alchemy of the Heavens. Anchor. I... | [
"But by that logic, there should be more carbon than oxygen as you lose oxygen along with the carbon. Twice as much oxygen in the case of carbon dioxide. "
] | [
"But by that logic, there should be more carbon than oxygen as you lose oxygen along with the carbon. Twice as much oxygen in the case of carbon dioxide. "
] |
[
"Assume that there's a body in a perfect vacuum with some kinetic energy. If the entropy always increases, does the body somehow lose its kinetic energy?"
] | [
false
] | ...Assuming that its gravity vectors compensated. Or does it only lose its thermal energy by emitting progressively colder and colder light? | [
"Its motion alone does not increase the entropy, nor decrease it.",
"If it is a blackbody, it will radiate energy and increase entropy. But if you ignore blackbody effects, its motion alone does not change the entropy. Giving the body some kinetic energy will be an act that increases the entropy of the system (re... | [
"I think this is the best answer, but to clarify for the OP (since she/he seemed to be implying a radiating body), a blackbody in motion ",
" lose kinetic energy as it radiates heat. This kinetic energy loss is due to the loss in mass (the object will not lose velocity if the radiation is isotropic). For an energ... | [
"Actually, this is the answer I wanted. In fact, I had the idea that the radiated energy is converted from the mass of an object, but, in that case, I wonder how this conversion mechanism works. But then I also thought that the radiation would consume the object's thermal energy hyperbolically (so that the temperat... |
[
"How did the Earth's mantle and core become so hot?"
] | [
false
] | Were the materials already hot when the solar system was forming, or did it happen later? | [
"Scientific American said it best \"There are three main sources of heat in the deep earth: (1) heat from when the planet formed and accreted, which has not yet been lost; (2) frictional heating, caused by denser core material sinking to the center of the planet; and (3) heat from the decay of radioactive elements.... | [
"The most recent paper I've seen has radioactivity at about half the Earth's heat budget:",
"http://www.nature.com/ngeo/journal/v4/n9/abs/ngeo1205.html"
] | [
"People can only measure the temperature of the surface of the Earth. Convection moves heat to the surface. It actually cools the Earth down faster, but for a while it will feel hotter than it would without convection."
] |
[
"Does an integer n exist such that e^n is also an integer? If so, what does n equal? If not, why not?"
] | [
false
] | [deleted] | [
"Yes. e",
"=1, so n=0 is such an integer. ",
"But aside from this, there does not exist such an integer. This can be seen using the ",
"Lindemann-Weierstrass Theorem",
". A consequence of this theorem is that if r is any nonzero algebraic number (ie: a root to a polynomial with rational coefficients), then ... | [
"This is correct, but it seems sort of like overkill to invoke the Lindemann-Weierstrass Theorem, since it suffices to note that the existence of any positive n such that e",
" is an integer would imply immediately that e is algebraic, when it is known to be transcendental. Of course, you can play the same game f... | [
"If e",
" is irrational but not transcendental, then e",
" is ",
" - that is, p(e",
")=0 for some polynomial p(x) with rational coefficients. But then e would be a root of the polynomial p(x",
"), contradicting the fact that e is transcendental."
] |
[
"If gravity bends light particles, is it possible we see some stars twice ?"
] | [
false
] | For example: Is it possible that light made 360 around some mass and then travelled back and one of small stars on the sky is Sun? How can we be sure about distance and location of stars on night sky? | [
"This does happen, but only for very strong sources of gravity. It happens around black holes, but we're only just this year getting enough resolution to see that happen. It's more common to see this happen around huge galaxy clusters. These clusters are very distant, and the background object they are ",
" is ev... | [
"Gravity lensing was used to watch Supernova Refsdal happen four times. The light didn’t make a 360 around an object, but it did follow four separate paths around a galaxy to reach us four times, weeks apart.",
"https://www.scientificamerican.com/article/scientists-see-same-star-explode-4-times/",
"[Edit] I rea... | [
"As you describe it no, but as the others have pointed out a mass in between a source and us can bend the light enough to make the source bend, as two images, four or even as a ",
"ring",
", depending on the alignment between the three participants.",
"The above example is two galaxies acting as lens and sour... |
[
"If a pregnant woman eats very little, will the baby take nutrients from the mother's muscles or fat stores? Or will the baby be malnurished?"
] | [
false
] | And the other way around. If the mother eats a lot will the baby be born larger? | [
"The human body is greedy, even a mother's. Eventually the mother's body will begin taking steps to save the MOTHER vice the BABY. So the baby will not be \"saved\" per se, but rather the fat and glycogen stores will still be shared in the body."
] | [
"I would just add that if the mother has gestational diabetes the baby can be born very big, which I guess you can compare to overeating. Women can get gestational diabetes regardless of diet but still essentially has the effect of causing the baby to put on weight due to the high levels of glucose they're exposed... | [
"I would just add that if the mother has gestational diabetes the baby can be born very big, which I guess you can compare to overeating. Women can get gestational diabetes regardless of diet but still essentially has the effect of causing the baby to put on weight due to the high levels of glucose they're exposed... |
[
"Why are subatomic particles so small?"
] | [
false
] | null | [
"They are subatomic... What's the alternative?"
] | [
"Superatomic"
] | [
"I don't understand... That's the definition of the term, smaller than an atom... They are what make up the atom... They can't be larger than the atom"
] |
[
"If someone was completely submerged in mercury how long would it take for that person to die after being removed?"
] | [
false
] | null | [
"It ",
" be toxic if handled incorrectly, but the ",
"liquid form",
" doesn't absorb quickly through skin. It's the inhalation of gaseous mercury vapor that tends to cause problems."
] | [
"What would you expect them to die from? A person can ",
" mercury and usually show no negative effects. I also would raise the question whether it would be safe for a person to be submerged in ",
" liquid with the density of a heavy metal."
] | [
"Well I heard that mercury caused disease....did i science wrong?"
] |
[
"Do Planets 'die' of old age?"
] | [
false
] | I misread the 'Do Plants die of old age' question, and now really want to know if planets 'die?' I suppose 'dying' would constitute no longer being geothermically and tectonically active. Thanks in advance! | [
"Rock planets like Mercury, Venus and Earth will become insert over time. As their cores cool the magnetic fields they emit will lessen which will allow the atmosphere escape. This is one reason why Mars is considered a dead planet."
] | [
"I'm not sure if they \"die\". Mercury/Venus/Earth will die as they will be absorbed by the sun.",
"As for the other planets, they may just float around in darkness for eternityas the sun's gravity will have weakened. I wonder if Jupiter and the other gas giants will look the same without the sun's energy."
] | [
"DOH! I forgot about those magnetic fields."
] |
[
"Would a massive object, moving near the speed of light, create a \"wake\" of effects behind it?"
] | [
false
] | If an object with a great amount of mass were to zip past our solar system at nearly the speed of light, what would it's effect be? Would it's brief gravitational presence affect our solar system in a notable way? Would it's effect be made-less by the fact it is only around for a brief moment? Is gravity the only conce... | [
"General relativity is very complicated. That is no understatement. Even if you specified exactly the parameters you mean here, like the exact rest mass of the object whizzing by our solar system, it's speed, and an initial trajectory at some time t, solving einsteins equations would still probably be impossible.... | [
"Thanks for that explanation.",
"\nI find it really difficult to find 'rules of thumb' associated with GR effects. I hadn't heard before that pressure gives a repulsive component."
] | [
"This Book is awesome.",
"Nobody likes tensor calculus all that much, but in chapter 4, the author does give some examples to build intuition, and discusses some of the counter-intuitive affects that are possible. "
] |
[
"Does \"shaking off\" an injury actually do anything?"
] | [
false
] | Like when you hit your finger with a hammer, knock your hand against a wall, stub your toe, or something that results in you sporadically shaking that body part, does it lessen the pain we feel? Or is it just a human reaction to try and "remove" what caused the pain? | [
"It is a learned reflex. Obviously, pain receptors are activated when you hurt yourself. By shaking your limb, or rubbing the injured area, you activate other receptors in the skin that 'interfere' with the pain signal and essentially divert the brains attention away from the pain. Hope this helps!"
] | [
"Distraction. Distraction takes your focus off the pain. "
] | [
"Well injured things get inflamed, which is basically a swelling to promote bloodflow, and thus healing. Centrifugal force it could help jumpstart this process of increased blood flow.",
"Also when you've been cut, the damaged endothelium collagen (inside-ish of blood vessel) coming into contact with the platelet... |
[
"What would the Earth be like if it didn't have plate tectonics?"
] | [
false
] | For example, if the core were just solid room temperature iron instead of being hot, what major geographical differences would you predict as a result? I'm not 100% certain whether this would even stop plate tectonics altogether or not. | [
"Hard and dead. The geothermal energy that drives the plates also creates the magnetic fields that protect us from solar wind that would strip away our atmosphere. That would be bad."
] | [
"This isn't quite correct. The magnetic field results from currents in the outer core driven by solidification of the inner core; the ",
"plates are driven",
" largely by density differences in the lithosphere, the outermost layer of the Earth. Two separate processes. Additionally, there is a lot of debate whet... | [
"A slightly less drastic change (sorry for answering a different question!) would to be ask: what would the Earth be like if it still had a hot core, but didn't have the specific arrangement of tectonic plate motion that it currently does?",
"The main features of current earth that depend on our specific system o... |
[
"how much would i weigh if the earth was not rotating?"
] | [
false
] | or alternately, how much effect does the centrifugal force of the earth spinning have on diminishing our weight? would objects fall faster? | [
"Yes there is an effect, depending on your latitude. ",
"Here is the ",
"formula",
", with the ",
"chart",
". ",
"Sometimes you have to take this gravity variation into consideration in international trade (so your buyer near the equator won't complain that the shipment weighs 0.1% less than expected o... | [
"Why any market would use weight instead of mass as a measure is beyond me."
] | [
"So, in what we call \"inertial\" reference frames, the perspectives of observers that aren't accelerating, and the laws of physics hold good, there is no such thing as a centrifugal force. In order to have a circular motion you need a ",
" force, some force that is pushing/pulling you inward to the center of the... |
[
"What causes rivers to snake?"
] | [
false
] | While checking out Northern Canada on Google Maps, I noticed some rivers were snaking much more than what I usually see. What causes this and what influences some rivers to snake more than others? | [
"In a curve the water is \"pushed\" towards the outer side from the flow, that leads to more erosion there and makes the curve even deeper. On the inside the eroded material can be deposited again. Eventually the curves get so deep that the river makes connections between them. Over time you can get what you see in... | [
"From what I remember from high school Earth science, a young river is relatively straight, a middle aged river meanders (snake) an old river develops oxbow lakes, where the meandering has gone to such extremes, that at certain places, the river will have sections that have been cut off from the main stream creatin... | [
"Well, old very snakey streams eventually cut through and leave you with small pools/ponds of water",
"Generally I think snakey streams come from the geology. If the land curves the stream does. If a stream hits a hill it bends. If the hill is soft it and the stream is strong it may cut through. If the stream is ... |
[
"Are the orbital planes of other solar systems parallel to ours?"
] | [
false
] | I know that we can observe exoplanets when they pass in front of their star and we can get a peek at the atmosphere because photons are able to pass through it and then reach us. However, it seems like such an event is very unlikely. Why is it that all of these exoplanets seem to be going directly in between their host... | [
"You're right that it's unlikely - we can only observe a small fraction of exoplanets using the transit method. So we have to survey huge numbers of stars to find the few that are lined up right at the right time. These are ongoing surveys that continually take pictures of large amounts of sky to see when stars get... | [
"Why is it that all of these exoplanets seem to be going directly in between their host star and earth in order for us to be able to view them so consistently?",
"Because those are the only ones we can detect.",
"Any exosolar planes that aren't perfectly lined up edge-on between us and their star make planets i... | [
"Yes, the star always wobbles, and when the orbital axis aligns correctly the wobble is parallel to our line of sight and the Doppler shift can be used to deduce the presence of exoplanets. It's called the radial velocity method and is common alongside the transiting method as a means of detection.",
"To \"notic... |
[
"I understand that space is huge, but if we're able to spot and locate stars 13 billion light years away, why can't we easily locate a suspected planet in our own solar system in today's age?"
] | [
false
] | Inspired by article about a potential 9th planet. | [
"I wrote about part of the problem ",
"here",
". However, we don't see stars billions of lightyears away. We see collections of stars billions of lightyears away. The light from all of the stars will add together into something that we can pick up with our specific telescopes.",
"Additionally, we're not looki... | [
"Finding \"Planet Nine\" will be no easy feat, just as it took thousands of years after the beginnings of astronomy, until the invention of the telescope for Uranus and Neptune to be discovered. Now we have very great telescopes and even a good number of them in space! These telescopes are good at taking in lots of... | [
"In addition to what has already been said, consider this: you can easily point out a distant star with your naked eye, but can you spot pluto? ",
"The problem with discovering a planet nine is similar. Although it is much closer than a distant galaxy, it is much dimmer and thus harder to find, especially with... |
[
"Since the surface pressure of Saturn's moon Titan is comparable to Earth, couldn't an astronaut explore it with nothing other than a respirator and arctic clothing? No space suit required."
] | [
false
] | null | [
"It is far too cold...a hundred degrees colder than the coldest temperature recorded on Earth."
] | [
"Chill being the pertinent verb here "
] | [
"Forgive my ignorance, but how?"
] |
[
"Does an egg get heavier, lighter, or stay the same weight while the baby chicken is growing inside?"
] | [
false
] | the time period is from when the egg is completely formed to when it hatches. | [
"Chickens are animals, which means they need oxygen to live. The egg shell is gas permeable to allow for respiration to occur. Just like any other cell, the embryo is taking in oxygen and emitting carbon dioxide. This process combined with a slow loss of water vapor would serve to make the egg lighter as time go... | [
"Not unless there's enough energy to generate matter-antimatter pairs. I feel like this is probably not the case."
] | [
"The key word there is ",
". As atoms/molecules/etc in the yolk are converted into chicken parts, like muscles/nerves/etc, the total amount of matter present doesn't change. Of course, the entrance and exit of oxygen and water vapor, and other things that can pass through the shell, can change the total amount of... |
[
"If I sat in a computer chair with a freely rotating seat on the north or south pole, after 12 hours would I be looking the exact oppsite direction as I started?"
] | [
false
] | [deleted] | [
"At the moment you put the chair there, you are already rotating (because you stand steadfastly on the rotating earth) and thus the chair in your hands is already rotating. Similarly, when you sit down your body is already rotating and the chair's seat plane is already rotating. So even if the is no further frictio... | [
"Can you please explain why a Foucault pendulum works then? "
] | [
"I've got to admit I've never seen that before... nice toy! ;)",
"I think such a pendulum is subject to the ",
"Coriolis effect",
", because it moves (at least in part) in longitudinal direction (i.e. along the north/south axis). Objects that are closer to the equator need to be faster to keep up with the ear... |
[
"Looking for D2 (molecular deuterium) phase diagram"
] | [
false
] | I need a diagram of the equation of state for molecular deuterium with temperature and pressure ranges from 0-300K and 0-1 MPa, or something near those ranges for an experiment I'm doing at work, and Google has only been able to provide me with diagrams in the GPa range or temperatures >1000K, which is not possible wit... | [
"I don't know one offhand.. looking at scholar/scifinder it seems most studies are aimed at high pressure/temperature scenarios, as you say. ",
"Here's one",
" that might be useful, though.",
"Excuse the presumption, but are you sure you ",
" one? The intermolecular forces which govern the phases/equation o... | [
"Just on a whim I'd image the extra mass begins to contribute quite a bit as you approach O degK or as KT starts to approach the energy of your lowest modes. Aside from that, I'd tend to agree."
] | [
"Well, the ZPE is part of the enthalpy. But as you go to 0 K, the \"non-classical\" contributions to what's going on aren't negligble anymore, and you really have to start thinking about stuff acting quantum-mechanically, and weird quantum-mechanical phases and stuff. And the mass certainly would matter there, sinc... |
[
"Why isn't the sky completely white at night?"
] | [
false
] | Shouldnt it - from earths perspective - be filled with stars, which are far from each other, but "lines up" from our view? Does the light reflections from these not reach earth? | [
"You've hit upon a very old question called ",
"\"Olbers' Paradox\"",
".",
"The solution relies on the fact that the universe is not infinitely old, so only finitely many stars and galaxies are observable and they collectively subtend an angle on the sky much smaller than the full sky."
] | [
"The solution relies on the fact that the universe is not infinitely old",
"To others, also keep in mind that even if the universe was infinitely old, we would not see any stars in the night sky besides our own galaxy's, since if the Universe was remotely that close of age, we would have been isolated from the re... | [
"First off you need to take into account the fact that these stars are extremely far away and that their intensity (power per unit solid angle) drops off at a 1/d2 relation where d is the distance away from the source. So when the light gets to earth it is extremely dim. ",
"This is actually at the heart of Olber... |
[
"What does /askscience think about the legitimacy of Near Death Experiences?"
] | [
false
] | That is, that they're legitimate evidence of anything asides from the fact that someone thinks they remember something strange happening. I've read stories of people who come back from having been dead for a few minutes and recounting stories of where they went and am curious if the scientific community thinks this is... | [
"I've yet to find an ethics board who will approve my proposed experiments on the subject..."
] | [
"Here",
" is a short article on what happens near death. ",
"It's likely just the brain having hallucinations as it goes hypoxic and people are thinking that means something, because some people desperately want to believe that this isn't all there is to it. "
] | [
"If by legitimate you mean \"do they happen\", the answer is yes! If you mean \"does this make it evidence of an afterlife/soul/etc\", the answer is no.",
"I think it's a fascinating topic to look into, especially when we don't know yet exactly ",
" they occur, but suspect DMT is involved."
] |
[
"What is this strange circle around the sun?"
] | [
false
] | Hi, is from few minutes ago. What's this perfect circle around the sun? | [
"It's called a 'halo,' and it's caused by sunlight passing through finely spread ice particles in a high altitude cloud layer.",
"A Huffington Post article about halos",
"The Wikipedia page on halos",
"(edited to fix the wikipedia link)"
] | [
"Here's a painting",
" of the same phenomenon observed over Stockholm on April 20, 1535."
] | [
"Thank you"
] |
[
"When we look into the night sky what exactly are the bright lights?"
] | [
false
] | [deleted] | [
"The Hubble Deep Field is a tiny area chose specifically for the lack of nearby stars that are easily visible. The area is roughly the size of a 10th of the full moon. ",
"The vast majority of what you see with your naked eye are stars which are local to our galaxy. There are about 10,000 naked eye visible stars.... | [
"Our galaxy is 100,000 lightyears across. On a clear summer day you can see 7000-10000 points of light. 99.99% of those are from a sphere around Earth with a radius of about 4000 light years, no more."
] | [
"All of the above.\nGalaxies, stars, planets, we can see them 'all' with our naked eye. However, most of the stars we can see from Earth un-assisted by telescopes, will be in our local galaxy, and the galaxies we can see are still in our local cluster. The local cluster is like your town. Your yard is the galaxy. Y... |
[
"[META] Monday Lab Meeting!"
] | [
false
] | [deleted] | [
"I've begun writing that pesky little dissertation thing"
] | [
"This week I'm on my own as everyone else has flown off to the states to visit our other site. Someone has to man the fort I guess...",
"Alllll byyy myyysellffff "
] | [
"Busy.",
"Got my experimental equipment finally set up after 3 months of prep ( 3.5m long flume tank to run simulated pyroclastic flows into), so have been carrying out the first tests in it. Mostly a case of finding the leaks, fixing them up, and getting a feel for how it all behaves. Been getting through prodig... |
[
"During a workout, how long does it take for the human body to use fat directly?"
] | [
false
] | [deleted] | [
"It's not so much time related as it is intensity related. Intensity here is defined as percent of max heart rate, so high intensity would be close to max heart rate.",
"In order to contract, your muscles need a high energy molecule called ATP. ATP basically gives energy to things to allow them to work. In order ... | [
"Do you mean 5/30/65? Why would adding more carbs and cutting fat cause you to burn fat?"
] | [
"If I understand you correctly, you confirm what I've read in a few sources I found credible. What I read is that you start burning fat. As your activity level increases, fat burning increases, but its max rate is limited. To expend more energy than the max fat burn rate supports, you start burning glucose. This do... |
[
"What happens to the cells in our body when we die?"
] | [
false
] | Do all cells cease function and die simultaneously when Brain activity ceases, or is it more gradual as oxygen and respiratory substrates being to run out after Brain function stops? | [
"It's more gradual. The medical definition of death is fairly arbitrary, especially since we can, to an extent, artificially extend metabolism beyond the endpoint of a lot of things you might call \"death\" (e.g. cessation of brain activity, cessation of natural heartbeat). Individual cells will die as they starve ... | [
"It actually occurs pretty rapidly once oxygen is no longer brought in. "
] | [
"Apoptosis (programmed cell death) occurs after our bodies die as no more oxygen is brought in. The biochemical reaction inside the mitochondria of the cell (cellular organelle basically the power plant) which creates energy cannot happen. ",
"Without ATP ( the energy that drives the cell), factors such as tumor ... |
[
"An esteemed director of our institute has recently retired, I am looking for an interesting/unusual scientific gift for him, suggestions?"
] | [
false
] | null | [
"Maybe you could get him an early edition of Principles of Geology or some other significant work."
] | [
"I used a rubics cube, glued it to fix and labled the sides accordingly to make an epsilon tensor. Did it for a birthday gift to a physics nerd, he was amused.",
"Dunno if your prof would like it aswell or if he even recognizes it. :)",
"Budget ~10$"
] | [
"Maybe it's the Waterboy fan in me.. but I always thought a sample of dirt/water/etc from all over the world would be neat."
] |
[
"Is it true that there are certain frequencies that cause fear in humans?"
] | [
false
] | null | [
"Would be nice with some sources."
] | [
"Yes. Certain frequencies of infrasound can produce that effect. These are below our range of hearing but can still be perceived, usually the result is something along the lines of feeling your skin crawl or feeling like you're being watched (increases in anxiety, unease, and fear).",
"Infrasound due to issues wi... | [
"At high intensity, various low frequency sounds will resonate with your internal organs. You can be made to lose control of your bowels and bladder. Systems like this have been used for crowd control, but the last time I heard of them they were used for repelling pirates off the coast of Africa. Those ship-moun... |
[
"Why doesn't the brain fry up in an EMP blast?"
] | [
false
] | If the neurons communicate using electrical and chemical impulse wouldn't the brain fry up if it is caught within a blast radius of an EMP. I haven't heard this happening , so what stops the mechanism that happens within an electric circuit that doesn't happen in Brain. | [
"Ions of sodium, potassium, calcium, and chloride react within the neuron to generate an electrical signal."
] | [
"I think he was being rhetorical. ",
"Transcranial Magnetic Stimulation (TMS)",
" is real."
] | [
"Our brains are not made of metal wire and gating semi-conductors. As such, changing magnetic fields passing through us do not generate electrical fields the way they do in metals and such."
] |
[
"Will a makeshift Faraday cage protect you from a Taser?"
] | [
false
] | If you were to weave copper wire into a shirt in a tight enough pattern, would it successfully redistribute a Taser charge? | [
"The OP doesn't actually need a faraday cage. He just needs something which will bypass the human component of the circuit between two taser darts."
] | [
"For a taser the current will flow from one dart (terminal) to the other. Conductive clothing provides a path of lesser resistance for the current, outside the body. The current is dissipated inside the taser, possibly damaging it because it is not pushing against such a large resistance."
] | [
"Anything conductive will do it. Chainmail will do nicely."
] |
[
"Does the Christmas tree I cut down still photosynthesize in my living room?"
] | [
false
] | null | [
"IRGA = infrared gas analyzer if anyone else couldn't quite get it from the context. "
] | [
"If cut and put in water relatively quickly (within a day), with the bottom part cut off so that it can pull up water, it probably is photosynthesizing. As long as it's 'drinking' (the stomata are open and it's pulling up water) and the cells are alive, I can't think of much reason to think it's not. I'll bring t... | [
"Thank you :) Doesn't everyone know obscure lab equipment abbreviations?"
] |
[
"How is a cold virus able to target specific areas of the body, ie the throat?"
] | [
false
] | null | [
"There are many, very different types of cold viruses, and each of them bind to different receptors found on cells in various locations (including the throat).",
"For example rhinoviruses bind ICAM1, adenoviruses bind CAR, coronaviruses bind ACE2, infuenza viruses bind sialic acid, etc.",
"Different cells will ... | [
"You've made this curious, stoned redittor very happy"
] | [
"To add to the previous post, this is the very reason why specific viruses vary in their pathogenicity. Retrograde viruses like HTLV or HIV are only able to bind with the receptors on specific leukocytes, thus making it statistically improbable to contract it from airborne or droplet particles since those leukocyte... |
[
"Why are breasts so attractive? After all, they're just fat and mammary tissue. Is it a psychological thing to do with breastfeeding as infants?"
] | [
false
] | null | [
"The two main running theories are ",
"a) Breasts are made of fat, and so good sized ones show a woman has had plenty to eat (implies good health and good skill at staying alive) and will be able to produce plenty of milk to feed her offspring. ",
"b) Humans are pretty neotenic (we look in some ways like juv... | [
"First off, I'd like to point out that as a primarily psychological topic that it is difficult, if not impossible, to differentiate whether or not breasts are attractive based on evolutionary biological impulses or cultural, sociological constructs. At this point no one in the primary literature (that I know of) ag... | [
"Does it have anything to do with \"These are forbidden, so I want them more\"?",
"Are breasts a lesser deal in societies that are less modest about nudity?"
] |
[
"How are multiple signals passed over wires (phone lines, fiber optics, etc...) without interference?"
] | [
false
] | I was thinking about the old days especially when most communication was over the phone lines which I know to be multiple individual strands of wire spanning thousands of miles with various interconnections. But, if my neighbor and I are making a phone call at the same time, how do the lines keep those 2 signals entire... | [
"There are three basic ways. Either you send the signals at different times and then reassemble at the receiver (time division multiplexing), or you send different frequencies or colors (frequency division multiplexing) and separate at the receiver, or you encode the different signals digitally such that they all a... | [
"If you're talking about internet signals then it kind of works like the post office. Your computer takes the message you want to send and wraps it in a digital \"envelope\" which has the source and destination address in it. The computer talks to the modem, which talks to the ISP modem. Then the ISP routing comput... | [
"Maybe I misunderstood your question. Are you asking how the receiver knows which multiplexing scheme is encoding the data? If that’s your question then the answer is it doesn’t have too. Every communication system has to be designed around one scheme or another as all the hardware and software would be different. ... |
[
"What explains the optical distortions in Jacques-Henri Lartigue's famous 1913 \"Car Trip\" photo?"
] | [
false
] | The photo in question shows This predates Photoshop obviously. The crowd is skewed to the left and the rear tire appears ovoid. | [
"There is a nice explanation with animations here:",
"http://www.largeformatphotography.info/forum/showthread.php?31903-Jacques-Henri-Lartigue-and-his-camera",
"The effect can still occurs in modern cameras. Most digital SLRs have mechanical shutters and many video cameras use rolling-shutter image sensors whi... | [
"I took a photo while dropping my cell phone, and the result looked somewhat similar:",
"http://imgur.com/fwumC4x"
] | [
"Here is a nice video of a propeller. There you can see what trippy forms the rolling shutter effect can produce: ",
"https://www.youtube.com/watch?v=LVwmtwZLG88",
" Basically it's the same effect as on the car, only in a video and with a much faster object."
] |
[
"Why does hyperventilation not produce alkalosis in the dog?"
] | [
false
] | Good morning askscience guys, I have a question that I've been thinking about for years. To the point, physiologically the human being has mechanisms to regulate acid-base control, and among them is pulmonary ventilation, in case the blood turns to a more acidic pH, the body generates hyperventilation to regulate the ... | [
"DVM here.",
"\nDogs do have the same acid/base compensation mechanisms as humans do, and you're right that a dog breathing too much will cause alkalosis. This is actually something we look for when trying to interpret bloodwork.",
"There are two reasons why dogs aren't getting clinically significant alkalosis... | [
"I’m case a vet doesn’t jump in with a more detailed highly sourced answer, vet tech here jumping in to say you are making a flawed assumption that normal panting counts as “hyperventilation” for healthy dogs. Dogs CAN get respiratory-related acid/base imbalances, especially if they are on a ventilator with incorre... | [
"Hyperventilating only causes alkalosis if you have increased ",
". You can, however, have a high respiratory rate without increasing alveolar ventilation by taking small breaths.",
"Example: let’s say we have a human with a normal breath of about 400 mL. 150 mL of that never reaches the alveoli. Only 250 mL do... |
[
"Which country will leave it’s continent first?"
] | [
false
] | Obvs this will take millions of years but which country will be the first to leave its continent? India is pushing into Asia which is continuing to raise the Himalayas, it stands to reason somewhere else is doing the opposite and will one day cease to be in its original continent. I wonder where is moving fastest and i... | [
"Probably the countries on the east side of the ",
"East African Rift",
", so portions of Ethiopia, Kenya, Tanzania, and Mozambique and all of Somalia (presumably Djibouti would sink into the ocean if spreading of the EARS continues and progresses to complete continental rupture and ocean basin formation). Thes... | [
"What an absolutely brilliant answer, exactly what I was looking for. Amazing"
] | [
"That's the nature of plate motion projections, i.e., they are inherently uncertain. Whether lithospheric rupture will occur in the EARS and when it will if it does is a relatively small uncertainty in these types of projections compared to deciding whether we'll see extroversion (i.e., the pacific ocean basin clos... |
[
"Can an electromagnetic chain/coil gun be used to launch spacecraft to orbit?"
] | [
false
] | null | [
"Aren’t all Reddit questions answerable on google "
] | [
"This question has already been asked a lot on ",
"/r/askscience",
" :",
"https://www.reddit.com/r/askscience/comments/58baxy/why_are_electromagnetic_railguns_not_used_to/",
"https://www.reddit.com/r/askscience/comments/76chjw/could_we_catapult_eg_satellites_with_a_large_and/"
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"To check for previous similar posts, please use the subreddit search on the right, or Google site:reddit.com",
"/r/askscience",
" ",
"Also consider looking at ",
"our FAQ",
... |
[
"IS it possible to break down atoms into their separate parts and re-arrange them how you like?"
] | [
false
] | [deleted] | [
"Nope, we can't do that.",
"It is possible to transmute certain smaller elements into certain bigger ones, but that just means smacking the atoms together at very high speed. For instance, to experimentally create element 118 (",
"ununoctium",
"), scientists put some Californium atoms at the end of a particle... | [
"Breaking stuff is ",
" easy. Rearranging subatomic particles isn't really a meaningful concept because ",
"Quite apart from the ",
"uncertainty principle",
", you face the extreme difficulty that the sort of forces available to you for the purpose of manipulating your sub-atomic particles are going to be t... | [
"Are you asking - can we break down the atoms into their individual electrons, protons, neutrons and bring them back together as a different element?",
"Like a matter compiler (from SciFi)?"
] |
[
"Why doesn't Cerenkov Radiation violate causality?"
] | [
false
] | When charged particles travel faster than the speed of light in a certain medium (usually water), they emit blue light in an analogous situation to an sonic boom. That's a really cool effect, but I'm stumped as to why something has to travel faster than the speed of light in a vacuum to violate relativity/physics in ge... | [
"When scientists refer to the speed of light related to causality ( c ), what they are actually talking about is the speed of a massless particle (usually the photon). When you hear about the speed of light in a medium slowing down, what you are hearing about is the macro level appearance of moving light. The rea... | [
"The light photons are moving at the speed of light, but the density of the fluids slow down the ",
" since the light bounces back and forth.",
"So some particles move faster ",
" than light, since light are more likely to collide with the fluids."
] | [
"Thanks for the helpful responses, HalfCent and Natanael_L! Anyway, I realized that of course the photons themselves must still move at c -- otherwise they would never outrun their fields, and there would be no radiation at all."
] |
[
"Sometimes after I sweat a lot I can brush any part of my body and salt will fall off. Why?"
] | [
false
] | And I mean like a lot of salt. I know it's salt because I've tasted it and it's extremely salty. | [
"A little off topic but have you ever had that checked out? It makes me think about you potentially having cystic fibrosis. One form is due to mutations in salt transporters that cause people to lose a lot of it. One of the old ways doctors would test children for it was to lick their hand and if it was super salty... | [
"Sweat is a way of cooling down. When you sport or when it's hot outside your body temperature rises, this increased temperature is not good for your body (our body/proteïns are optimized to work best around 37.5°C). So we need to cool down by sweating. Sweat is actually just water with ammonia/urea and salts (Na, ... | [
"That's not off topic. And I dunno. Would this kill me? Because I've been doing this for years. "
] |
[
"Why do many animals have a \"rare\" type that is either solid white or black? Also why are they not any other color."
] | [
false
] | [deleted] | [
"Its a lack of pigmentation expressed in animals, caused by genetic mutation. Since all animals have genes related to pigmentation, all animals can have mutations in those genes. There are a few basic types: ",
" animals do not produce melanin. ",
" animals lack yellow pigmentation.",
" animals lack red pigme... | [
"I don't know the answer to your first question other than it's to do with genetics, but animals are usually not other more exotic colours because those colours are usually not effective for their purpose. A crimson red lion wouldn't be a better hunter than a beige one in an African savanna."
] | [
"I don't really know the answer to your broader question, bu tin the case of the squirrel pic, I'm pretty sure the white one is an ",
"albino",
". Black and grey and sorta brown squirrels are common in my experience, but I've never seen an all-white one."
] |
[
"Ask Anything Wednesday - Engineering, Mathematics, Computer Science"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! ... | [
"sending information virtually instantaneously over long distances",
"It's not how this works. There can be no superluminal information transfer and quantum entanglement doesn't affect it at all. It's true, at least for now, that it seems there is no delay in setting the particles state, but it has little to do w... | [
"There's been much publicity lately about using quantum entanglement as a means of sending information virtually instantaneously over long distances. ",
"But one thing I don't understand: How do you keep the quantum systems (the ones which contain the entangled particles) from decohering prematurely — before your... | [
"The theorem does hold. It has been proven."
] |
[
"Why can we effectively fight off bacteria but it seems like modern medicine can't help at all against viruses. Why are we still helpless against viruses?"
] | [
false
] | null | [
"Viruses and bacteria are inherently different things. Bacteria are simple prokaryotic organisms and with that come with a variety of ways you can destroy them (based on their cell wall type, etc.). Viruses are a little bit more tricky because they aren't \"alive\" in the traditional sense. They are a bundle of DNA... | [
"Antiviral drugs do exist. Just that they don't have virucidal activity (i.e. they don't directly kill the virus). You see, viruses are simply protein and genetic material, and coming up with a drug that selectively destroys these structures in the virus while maintaining all other proteic structures in our body in... | [
"A bit simplified: Viruses are mostly internalized using membrane receptor interactions. Should those receptors be missing, they are suddenly without a way to enter our cells. ",
"HIV-1 utilizes CCR5 (=CD195) and CXCR, originally chemokine receptors on Th lymfocytes. And HIV-1 resistant people (at least the type ... |
[
"Regarding the current news of the FDA revoking the approval of Avastin, why is VEGF a target for cancer treatment?"
] | [
false
] | So, today, the FDA revoked the approval of Avastin for use in the treatment of breast cancer. Apparently, Avastin (bevacizumab) targets vascular endothelial growth factor-A. From my limited knowledge, it seems like VEGF is utilized in the human body for the growth of vasculature as a normal function of the human body a... | [
"Any cancer treatment will almost certainly affect your normal tissue as well - remember that cancer is ",
" gone haywire.",
"VEGF is an attractive target for cancer therapy because it is often overexpressed in cancer cells. This allows the tumor to recruit a massive blood supply, allowing it to grow and sprea... | [
"To elaborate: the new blood vessels which grow info a tumor are often far from perfect and leaky. This causes elevated oncotic pressure within the tumor, which in turn diminishes uptake of chemotherapeutic agents in the tumor. VEGF receptor blockers thus make other therapy more effective. Moreover, the tumor itsel... | [
"Typically VEGF is most active in tissue remodeling, most often from wound healing or cancer. I suppose for growing kids, there would be systemic tissue remodeling throughout the body, or possibly body builders who are building muscle.",
"Anyways, if the tissue is not in the process of remodeling (either muscle b... |
[
"How can acids with a different pH level have the same concentration?"
] | [
false
] | null | [
"Some acids are more likely to donate a proton than others. So an acid, that donates protons easily, will have a lower pH level than another acid, which hardly gives away its protons, although they both have the same concentration. "
] | [
"And since ",
"pH is a measure of the dissociated proton, H",
" , concentration",
", not the total dissolved material concentration, it is only the same for two acids if both acids dissociate in solution to exactly the same extent.",
"So for instance, if a 0.1 molar solution of a strong acid like HCl is mad... | [
"Concentration is not a measure of potency.",
"It's purely a measure of how many acid ions are dissolved into a solvent, as a ratio.",
"It's a pure ratio of solvent to solute.",
"Strength is a measure of how many dissociated ions are formed when the acid is dissolved into an aqueous solution.",
"A string ac... |
[
"If Mars once had complex multicellular life, would there be any evidence leftover on the surface today?"
] | [
false
] | [deleted] | [
"The earth is about 4.5 billion years old. Up until 600 million years ago there was no multi-cellular life. So 3.9 billion years of no life or single cell life.",
"More complex forms of life took longer to evolve, with the first multicellular animals not appearing until about 600 million years ago. ",
"https... | [
"It's highly doubtful that Mars ever had complex multicellular life; even Earth with it's fairly ideal conditions only developed complex mulicellular life somewhat recently, within the past billion years, when Mars had already become inhospitable to surface life. However, simple unicellular life can leave traces t... | [
"Yes unlikely unless Eukaryotes cells managed to hitch a ride from Earth to Mars via some like a recent (i.e. 600 million year old or less) meteor strike, but even then if it landed on Mars it would find an environment that would be extremely hostile to life...so no there is/was no multi-cellular life on Mars.",
... |
[
"If Mars is a candidate for terraformation, could the same process be done for Venus?"
] | [
false
] | I understand very small basics of the process of terraforming but my curiosity essentially stems from the similarities in size of Venus to Earth. I know that Venus is much hotter and has atmospheric pressures that would crush us but are there viable techniques that could significantly alter the planet in order for the... | [
"Venus is very close to the sun, making it very hot and the radiation levels very high. \nIt would be a lot harder to live there than Mars."
] | [
"Venus has a size roughly like Earth's and a nice and thick atmosphere to work with in terraforming imaginary ideas. The main problem of Venus though is that its day last to long, about 243 earthly days, and that makes it a difficult planet to terraform even for a longterm project. We would have to engineer life (p... | [
"So Venus would essentially require its 'spin' to increase before Earth-like plants could be grown there? That's one thing I hadn't considered actually despite knowing it was longer than its year, one of the factlets I took in as a kid. While there are active volcanoes on Venus would this be a likely problem too?... |
[
"When building like the Empire State Building (or taller) get too old and need to be brought down, how will they do it safely?"
] | [
false
] | null | [
"A Japanese construction company demolishes buildings a floor at a time. ",
"Link with video and explanation",
". Seems like it would be useful to tear down a building like the ESB when it has reached end of life. "
] | [
"From the article: ",
"Basically, construction workers build a hermetic structure covering the top floors of a tower that is supported by powerful jacks. Inside the structure are the heavy machines and demolition crews, who take apart the walls and cut the floors into concrete slabs that they lower to the ground ... | [
"How long can we expect a building like ESB to last?"
] |
[
"Lightning storm while white water rafting; which is safer?"
] | [
false
] | So we just had a cubicle debate when a coworker informed us that he went white water rafting this weekend. If you're out on the river, and a lightning storm rolls in, are you any safer in the water in a rubber raft or on the ground? Consensus here was that as long as you're in the rubber raft, being insulated from grou... | [
"I think google is encouraging you to do this... for science.",
"Seriously though, during any thunderstorm, your first priority is to get off the water. Water is a pretty good conductor of electricity, so even if a strike occurs at a fair distance away, you could still be electrocuted. Also, chances are that y... | [
"The rubber raft does not make you safer. Air is highly resistive. It's more resistive than rubber. The bolt has already travelled through a couple miles of air. A few mils of rubber will make no difference. Same goes for your car tires. Its the skin ofthe car (hopefully a metal) which will save you. Not the tires.... | [
"I reckon because you're in a river which is presumably surrounded by higher banks, even cliffs, and trees, then you're less likely to be struck by lightning, as it'd tend to hit something higher. In terms of in the river or on land, I'm not sure."
] |
[
"Can you die from a magnet? How strong does it have to be?"
] | [
false
] | Is it possible to kill a human with a strong enough magnetic field? If so how strong does this magnetic field have to be? And is is even possible to generate such a strong field? | [
"A 16 tesla field is enough to levitate a frog. As I recall, the magnetic field of a magnetar is enough to shred a human, but it's in the gigateslas. "
] | [
"Actually, as I understand it, extreme magnetism will break molecular bonds. Extreme magnetic fields distort the behavior of electrons. Given enough distortion, it is possible to turn normally reactive elements into chemically inert substances. Just splitting enough internal water into pure hydrogen and oxygen w... | [
"What will actually kill a person in those circumstances? "
] |
[
"If whale pods tend to stick together through generations, how do they prevent inbreeding?"
] | [
false
] | Pods I've heard are gigantic families of whales. Mothers, fathers, children, grandparents, uncles, etc. With this I've heard they tend to stick together and the kids tend to hang around their mothers even in adulthood. If this is the case, how do these younger generations get mates to bring calves into the world that a... | [
"According to ",
"this paper",
", killer whale pods will temporarily associate with each other and mating will occur between whales of different pods. This helps reduce inbreeding even though the whales don't disperse from their natal pods.",
"In other species, like the ",
"sperm whale",
", one sex will d... | [
"One of the main theories I've heard is that orcas will only mate with those that have a different regional 'dialect' than they do. Since all their relatives have the same dialect as they do, this functions to prevent inbreeding. ",
"Here's a basic summary of orca 'culture' and mating behaviors."
] | [
"They also follow annual migration routes -- colder waters for better hunting and warmer waters for breeding and rearing calves. They will frequently wind up in the same mating grounds at the same time of the year. Humpback whales will even actively compete for mates, not unlike dolphins. It's kinda' cool.",
"... |
[
"Electrons and elemental properties"
] | [
false
] | null | [
"Different elements by definition have a different number of protons in their nucleus, and different nuclear charges, which in turn determines how many electrons they're likely to attract. All chemical and material properties depend on what the electrons are doing. (And in terms of the total electronic energy, it's... | [
"You're right about the electrons, it's a large part of chemistry. Each atom has a different ",
"electron configuration",
". Some electron configurations are strongly correlated with certain chemical properties. For example, noble gas configurations correspond to very high stability and inertness."
] | [
"You're adding protons ",
" electrons. Again, opposite charges attract. It takes energy to separate them, so you don't have many things in nature that just sit there with a net positive or electric charge on the larger scale. So you do not just have 79 protons but 79 electrons as well in a gold atom. ",
"I can ... |
[
"Is the speed of light defined by special relativity or assumed by it?"
] | [
false
] | null | [
"my question is whether all observers agreeing on the speed of light is an assumption of SR",
"Yes, that is a postulate (an assumption).",
"I guess what I'm asking is, did Einstein figure out that the difficulties people were having with electromagnetic field theory could be resolved by assuming that the speed ... | [
"Thanks 👍"
] | [
"It's a postulate of SR that there exists a finite upper limit to the speed at which physical signals can propagate. It's a ",
" of electromagnetic theory that light propagates at this speed."
] |
[
"Can human blood boil?"
] | [
false
] | If I had two cups of healthy human blood and placed it over a heat source, would it boil? At what temperature? Would all the water evaporate and leave a thick layer of dried blood? | [
"Yes, this very process is how the pigment ",
"Prussian blue",
" was historically synthesized - by boiling down blood in order to extract the iron.",
"Just like any other aqueous solution, you can boil it at approximately 100 degrees Celsius or above. The vapour profile of the solution depends on the vapour p... | [
"That's a common misconception though. Your body is very well capable of keeping the internal pressure in your blood vessels to not have blood boil."
] | [
"Interestingly enough, one of the reasons Felix Baumgartner needed to wear an airtight pressurized protective suit for his space-jump was that the low pressure at that altitude would've caused his blood to start boiling."
] |
[
"Could graphyne potentially serve as a carrier of electrical current over extreme distances?"
] | [
false
] | [deleted] | [
"'As if they were massless' here is a very misleading if you don't know what it's referring to, which is ",
"effective mass",
". Which is something quite different from 'mass' in a proper sense. It's the 'mass' that they'd have defined by how they respond to an electrical field, if you pretend they act classica... | [
"Its actually pretty easy to make large sheet of graphene.",
"You can easily make a few cm",
" sheet with a CVD furnace and theroll to roll methods that Samsung uses can make huge areas of the stuff"
] | [
"I haven't seen many. But science journalists are often wrong anyway. Graphene is not a superconductor. It can support a ",
" over short distances if you place it between two actual superconductors, due to the ",
"Josephson effect",
". Some people are just confused I suppose. "
] |
[
"How exactly does a large array of radio dishes spread across a field like ALMA in Chile create a 10 mile wide \"telescope?\""
] | [
false
] | I don't understand how you could get images from 66 radio dishes spread around a field. . | [
"Aha! This is my field, and I may be able to help you with this. Beware: we are going to go deep, deep down the rabbit hole into the land of aperture synthesis interferometry. Even those who've been doing it for years may still find it confusing at times, so if it seems totally incomprehensible, that's normal. ",
... | [
"I really don't understand this but I got a jist. I guess the main technique is measuring waves at different locations and noticing the time delay and somehow overlapping them to make an image or.. un-overlapping them to make an image? Oh boy. I guess a good question to start is. What is a baseline? That would clea... | [
"A baseline is what you get when you combine the signals from two telescopes. Think of it as two telescopes tied together into a pair to form a double-slit experiment.",
"A single dish telescope will give you an image, albeit an extremely blurred image (because a single dish has poor resolution). "
] |
[
"Is it possible for nerves in the body to become intertwined or misconstrued? Would it be possible for a hair being pulled to be felt on another hair as if it happened to that one?"
] | [
false
] | null | [
"I'm not sure if this isn't something completely different, but isn't it quite common for pain to be \"moving around\" and be felt at locations different from the pain source?"
] | [
"I have never heard of nerves getting mixed up or anything like that. As a general rule of thumb, all sensory nerve fibers refer back to a single spinal nerve called a dermatome (linked below is a dermatome map). Each spinal nerve supplies a certain area of the skin with sensory input. I have never heard of dermato... | [
"So whenever a patient walks into the doctor and says my knee hurts, there are many different things that could be wrong. In addition, how the patient communicates pain to the doctor and how the patient perceives pain is different for each person. This is why the doctor manipulates the patient and asks many differe... |
[
"Is our galaxy moving from momentum from the big bang or just from gravity-dark energy?"
] | [
false
] | So when I was younger my understanding of the big bang was that all matter blasted away from a center point and that the galaxies where all hurdling away due to this. I then learned how the big bang wasn't an explosion of matter but the creation/expansion of space time. So I just realized that we might actually be sitt... | [
"So I just realized that we might actually be sitting still in the universe other than the momentum gained from gravity and dark energy",
"The universe has no frame of reference. A bullet train might be sitting still and the rest of the universe flying past it. Any frame of reference is correct.",
"Velocity, po... | [
"If you're in a box, and it's moving (or sitting still) you cannot tell how fast it is moving.",
"However, if a force is exerted on it (such as in an elevator), then you ",
" feel the force, as it moves relatively to ",
" which means ",
" move relative to ",
" While you could never determine its velocity,... | [
"Galaxies are moving away from each other because of gravitation, not the initial momentum.",
"If you have an infinitely large space, and matter distributed in that space in a homogeneous manner, General Relativity predicts that the result would be a situation where 'space expands'. This is called the FLRW soluti... |
[
"If light travels in a straight line, why aren't there gaps between rays of light if the source is far away?"
] | [
false
] | [deleted] | [
"Light isn't really rays, that's a simplified way to picture it that captures a lot of its behavior but fails in other ways. Light is a wavefront that spreads out as it travels, and the rays are defined to point perpendicular to the wavefront - in the direction the wave is moving at that point. So there are infinit... | [
"There are, but you have to get really really far away. When looking at distant x-ray or gamma ray sources (like from other galaxies), the photons typically arrive one at a time instead of in a continuum."
] | [
"Sort of tangentially, it's my understanding that the photon view comes into play as the amount of energy that can be exchanged between the wavefront and your eye/camera is quantized into discrete units (the photons), but this has more to do with the interaction of the light and the detector and, though people (mys... |
[
"Question about the expanding universe and space ships."
] | [
false
] | This is something that has boggled my mind for a while, the universe is expanding, galaxies are flying the the universe at incredible speeds from what i read. Now how is it that when a space ship leaves our atmosphere the planet doesn't just fly away and leave the space ship in it's dust. | [
"Because metric expansion doesn't work ",
" like that. Whatever you've been reading, you should put it down.",
"The effects of metric expansion — which do ",
" involve \"galaxies flying [across] the universe at incredible speeds\" — are only really detectable on scales in excess of about a hundred million lig... | [
"\"space is expanding\" doesn't mean that space is expanding outward from a central location like an explosion. ",
"it means that the space between space is expanding much like if you consider baking a loaf of raisin bread. The raisins represents galaxies and the bread rising is an example of the universe expandi... | [
"Ahh...now that makes more sense, thank you!"
] |
[
"What is the most interesting protein you know of?"
] | [
false
] | I once heard how influenza has a sort of knife--grappling hook protrusion made out of alpha helices that swings out and sticks into the cell wall when the pH changes. I don't know if that one is accurate. What else do you know about? | [
"My top three:",
"ATP Synthase",
"-This is literal rotary motor in your cells that turns a H",
" gradient into chemical energy by pushing bonds close to eachother. (And changing the binding environment)",
"Heat shock proteins",
"- These are little molecular barrels which collect mis-folded proteins and gi... | [
"PKM zeta",
"I guess I'm biased because I work on this one :)"
] | [
"Myosin motors (and similar proteins) use ATP energy to literally ",
" down these cytoskeleton elements",
"I've shown the ",
"Inner Life of a Cell",
" video (a must-watch, if you haven't seen it already) to people from elementary school up to middle age, both scientists and the lay public, and when it gets ... |
[
"Besides potentially causing hypothermia, what makes cool water enjoyable to drink, but horrible for swimming?"
] | [
false
] | null | [
"From an evolutionary standpoint, you drank water at whatever temperature the water source was. Once you start looking past the point where humans started inventing things, it's sometimes not possible to chalk up something humans do to strict evolution. We drink ice-cold colas because we like ice-cold colas, not be... | [
"According to this source (",
"http://www.sportsscientists.com/2008/01/exercise-in-cold-part-ii.html",
"),\nthe most dangerous factor isn't hypothermia but the so called Cold-shock response:",
"\"One of the first things you experience when submerging yourself in cold water is something called the \"cold-shock... | [
"Your questions assumes that humans prefer drinking cool or cold water. That may not be a universal preference among humans, just a cultural preference in the US and perhaps certain other countries. I grew up in Europe and never put ice in water or even other drinks...it just wasn't commonly done. I still drink ... |
[
"Are gallbladders and lymph nodes actually green as they are always shown in diagrams?"
] | [
false
] | Neither bile nor lymph is actually green, so are gallbladders and lymph nodes always depicted as green just by convention or because they are actually green? | [
"For a gallbladder, yes but when it’s full. Bile tends to be a dark greenish color which makes the gallbladder appear green. However, the lymphatic system isn’t. Lymphatic vessels are more of a white color while lymph nodes are a pale brown. I believe the lymphatic system is usually drawn green in illustrations to ... | [
"Gallbladders color can range from tan, to pink-purple, to gray-green. The bile inside is usually consistent with the color of the overall gallbladder. Dark green bile tends to stain the mucosa, and if the gallbladder wall is thin enough, will change the color. ",
"Lymph nodes are almost always tan or tan-brown. ... | [
"Well, the actually gallbladder when you're looking at it is not green. It's like any other viscera. But if you accidentally poke it or spring a leak in the cystic duct as you're taking it out, you'll see green coming out. Looks really gross on the laparoscopic camera."
] |
[
"How much has solar luminosity increased in the past billion years? Three hundred million years? It it significant?"
] | [
false
] | I am having difficulty finding a good answer to this question. Thank you. | [
"I found this in the footnotes of ",
"a 1972 paper by Carl Sagan and George Mullen",
" about the ",
"Faint young Sun paradox",
":",
"Estimated values of the increase in solar luminosity, AL, over geologic time are: 60 percent [M. Schwarzschild, R. Howard, R. Harm, Astrophys. J. 125, 233 (1957); (7)J; 30 p... | [
"According to ",
"this paper",
", the solar luminosity a billion year ago was about 90% of what it is today. If you can not access the article, there is the arXiv preprint version that is basically the same."
] | [
"It's saying it's up 40% from what it was originally, or in other words it used to be 70% of what it is now."
] |
[
"Why don't apes have facial hair but we do?"
] | [
false
] | What is the we came to have facial hair but our cousins don't? especially the region above the upper lips. | [
"They do!",
"Chimpanzees are the closest relations to us, and they most certainly have facial hair.",
"Example 1",
"Example 2",
"Many many more examples"
] | [
"Layman here. They do have facial hair, but not in the same exact shapes/patterns we do. Facial hair is considered a secondary sexual characteristic, and as such, it's highly susceptible to selection. Basically, it's about what the females prefer."
] | [
"Notice none of them have mustaches."
] |
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