title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"I would like a very basic summary of the Quantum Field theory."
] | [
false
] | Hello Reddit. I am sophomore in high school. I was in my Chemistry period and we were discussing the emission of photons from electrons when enough energy is given. My instructor mentioned the Quantum Field, but VERY briefly. The idea of the theory really intruiged me, but my instructor held off from talking about it due to the number of people in my class that could be offended (religious affiliation and whatnot). So Reddit, could you give me very simple (if possible) summary/understanding of the Quantum Field theory? Thanks! | [
"I wrote up a description a while back ",
"here",
"."
] | [
"Let me give it a go.",
"Imagine you have a guitar. Each string you can pluck makes a certain note. When struck together, you get a cord. When you're not strumming the strings, they themselves have properties. The properties that allow the note to emerge when it strums are fairly complicated to envision directly,... | [
"QFT is a pretty advanced topic, not usually taught until graduate school (masters/PhD level). It combines quantum mechanics (which tell us, for example, how electrons are arranged around an atom) with special relativity (which tells us how things behave when they're going really fast relative to each other), so to... |
[
"Please, if somebody knows about the physics of black holes, can you explain a bit regarding their mass? (Resubmitted)"
] | [
false
] | I recently watched some documentary on Youtube about black holes. In the film, Kip Thorne stated that the notion that a black hole is a super-dense sphere of condensed matter is wrong, and that any matter that falls into the black hole is destroyed, and ceases to exist. If this is the case, how is it that the more matter that enters a black hole, the more the mass of the black hole increases and in-fact, black holes come in many different masses, from the mass of a small town, to many billions of solar masses. Why aren't all black holes the same? Please keep in mind I know almost nothing about the physics of black holes, and may have stated some of the question incorrectly, or noob-like. I do however understand that matter/energy (information?) is always conserved, so I guess I am really questioning exactly what he meant. Thanks! | [
"Some qualities are expected to be conserved, such as momentum and charge"
] | [
"There's no telling, but another thing we know of where all matter is obliterated is the beginning of the universe, so some people think there might be a universe inside a black hole, and conversely, that our ",
"own universe might be inside a black hole",
"."
] | [
"Matter falling into a black hole is not destroyed, nor does it cease to exist. No one actually knows what happens to matter besides that, however, it may be that when people say matter is \"destroyed\", they really mean it is ",
". The quality that makes it massive remains, but any other qualities it had outside... |
[
"How is it that Jupiter can keep earth safe when they orbit the sun differently?"
] | [
false
] | null | [
"In addition it's worth noting: ",
"1) Jupiter can attract and \"suck\" in an inbound comet or asteroid as you mentioned. ",
"2) But more often, Jupiter simply deflects and bends the orbit of asteroids and comets so that they are flung out of the solar system entirely. ",
"3) Finally, Jupiter can also bend/fl... | [
"You can imagine the gravity of the sun being like a cone with the sun at the pointy end. All the planets are spinning along the inside of that cone at different heights.",
"Something small that would keep falling down while spinning in circles towards the sun will usually eventually get near to Jupiter and get s... | [
"I think I remember some discussion that early in the solar system Jupiter contributed to the bombardment of Earth. While clearing parts of the solar system it threw all sorts of things into the inner solar system, but since there are less objects now it deflects more away? I'll try to find a citation of what I saw... |
[
"What causes stars to switch from Hydrogen fusion to using heavier elements?"
] | [
false
] | When talking about the life cycle of stars, people often say something along the lines of “when a star runs out of hydrogen to fuse into helium, it has to start performing fusion with heavier elements to keep producing energy.” But this glides over a lot of details and also frames the star as having some sort of agency, which is obviously not the case. So my questions are: Thanks in advance! | [
"In short, gravity compresses the core as fuel is exhausted, which raises the temperature, which eventually gets it hot enough to make the ash from the previous fusion burning stage to itself start fusing.",
"During the main sequence hydrogen slowly burns to helium, so helium is accumulating in the core. The star... | [
"Fine explanation by ",
"u/VeryLittle",
". ",
"I'd just like to add that the equilibrium he mentions, is a balance thing between outward pressure and inward pressure from gravity. ",
"Outward pressure comes from the energy released by fusion of hydrogen and then increasingly heavier elements.",
"As the li... | [
"Switching maybe isn't the best expression, after hydrogen burning doesn't stop. It just moves to outer regions, where there is more hydrogen left.\nSo there only is an additional process, when the needed temperature is reached."
] |
[
"Is there a way of calculating how much energy is released when speaking?"
] | [
false
] | [deleted] | [
"Are you more interested in the energy embodied in the actual sound produced, or the energy your body uses in producing it? The first one is easier to answer."
] | [
"You can convert the dB level back to sound intensity. That, if you know how far the dB level is from your mouth, you can roughly know the original required power. Then you have to factor in losses in several assumptions you make."
] | [
"There are a couple useful equations here.",
"First is how we calculate sound intensity:",
"L (in dB) = 10 x log (I/I0), where I0 is the \"standard reference sound intensity\" of 10",
" W/m",
" . ",
"The second is what relates intensity to power:",
"I = Power/Area ",
"If we assume a spherical distribu... |
[
"Is there a reason why radio towers aren't used for wifi?"
] | [
false
] | The title says it all really. Is there a physical reason why radio towers aren't used for wifi. It seems to me that something like Google fiber, where they are trying to provide high speed Internet to people at a low cost could be mitigated by providing high power radio waves. I know about the inverse square law, but something like having the main depo the same as the exchange point (which can provide much more than 1gbps, probably closer to 1tbps in total) would be able to blast out a decent wifi signal with Google instead handing out cheap repeaters. It gets rid of the cost of wiring up to individual houses, speed boosts are all there still and the range is arguably better, since no longer do you need to be in your house to get signal. Anywhere in your town is fair game. | [
"wifi is in what is commonly referred to as the \"junk band\" - reserved for consumer use. The FCC limits how far the signals can propagate for that spectrum. and the reason for that is there is a limited amount of it. You don't want signals interfering with one another. You know how if you close neighbor is using... | [
"Radio towers (specifically, cell towers) are certainly used for ",
". It's just called GPRS or HSDPA or 3G or 4G or what have you. \"Wi-fi\" (that is, IEEE 802.11 wireless LAN) is optimized for local area usage and would not be a good choice for long-distance data transfer. Of course, as the number of users per ... | [
"To add, the radio signal is very low bandwidth when it travels. Best analogy I've heard. ",
"Stand on top of a mountain and shout down with a megaphone to a crowd below. They can hear you perfect right? Now imagine all them shouting back at you, hard to hear right?",
"It is easy to send out signals to places ... |
[
"Are all the particles of the same kind in the universe, say protons, identical? If not, what makes them unique?"
] | [
false
] | null | [
"There is no evidence to support otherwise",
"In fact, there is ",
" of evidence to support the fact that they ",
" identical."
] | [
"It's not just that we haven't noticed a difference. Quantum waveforms don't add like regular probabilities. If you get the same state two different ways, they'll interfere. If you have two different states, they won't. Two \"different\" protons will interfere with each other, so we know they must be identical."
] | [
"Yes, they are fundamentally identical."
] |
[
"What would a highly curved universe look like to an inside observer?"
] | [
false
] | This might be more of a mathematics question than a physics question. Under the FLRW model there are two possibilities for a non-flat universe: positive curvature (3-sphere) or negative curvature (hyperbolic space). Let's assume a fixed static metric for simplicity, that the universe has existed forever, and that the curvature is high enough to be noticeable. Reasoning by analogy with the two dimensional case, I'd expect far away objects in the sphere to look bigger than in flat space, eventually covering all your field of vision when the object is at the antipode. Also, I think you would see an (inverted?) image of your back in the background at all times. In contrast, objects in the hyperbolic space would look much smaller than in flat space the further they are, since parallel lightrays eventually diverge. Is this correct? Or are there other effects due to the finiteness of the speed of light? Does anything interesting happen if the observer is moving at relativistic speeds, and/or if we include a slight metric expansion? I'm basically trying to get a feel for the global aspects of the geometry from the perspective of someone inside. | [
"The program ",
"Curved Spaces",
" shows this well for both positive and negative curvature. Your second paragraph is correct."
] | [
"All of what you guessed for the 3-sphere and hyperbolic space is correct. ",
"The other questions are a bit too much for my puny brain to work out. You might be interested in googling 'angular diameter distance' and reading as much as you can about it, and see if there's any good treatment for a spatially curved... | [
"That's deceivingly simple, t must be the retarded time, that is the time at which the light from the object has to have been emitted for you to get it now. Computing this involves an integral over time including the behaviour of the scale factor at all intermediate times."
] |
[
"You hold Vitamin B12 under your tongue to absorb faster. Would the same apply to alcohol or caffeine?"
] | [
false
] | [deleted] | [
"It works for a lot os substances. What happens is the by putting something under your tongue that substance eventually gets absorbed directly in the bloodstream, while if it is ingested, it first goes to the stomach and intestines, then to the liver, and only then to the main blood supply, after suffering some tra... | [
"Works for nitroglycerine very well."
] | [
"Sublingual absorbtion definitely works well for caffeine. I don't know about alcohol, but I know holding it under your tongue wouldn't be pleasant!"
] |
[
"How are we affected by the speed of our travel through the universe?"
] | [
false
] | Let me be more specific. If we're travelling at insane speeds through the universe (due to the earth's spin, the rotation of the solar system and the speed of the solar system around the galaxy and then the galaxy's motion through the universe) then how do we accurately measure the speed of light due to the fact that the tools to measure it are also moving through space but the speed of light is constant and therefore what we perceive to be the speed of light might be faster or slower depending on our velocity through space. Also, how are we affected by the time dilation of this motion and could we therefore be experiencing our universe slower or faster than other objects in the universe? Thanks guys | [
"speed of light is constant and therefore what we perceive to be the speed of light might be faster or slower depending on our velocity through space",
"Nope. The speed of light is constant ",
". (Inertial means no rotation or acceleration) It is what is known as a Lorentz-invariant quantity.",
"Two observers... | [
"If we're travelling at insane speeds through the universe",
"Compared to what?",
"Also, how are we affected by the time dilation of this motion and could we therefore be experiencing our universe slower or faster than other objects in the universe? Thanks guys",
"Time dilation is only defined with respect to... | [
"Compared to what?",
"There was an article on IFLS where they showed how fast we are moving in total relative to our nearest galaxy which the milky way is heading towards. It's a couple of million mph.",
"As for time dilation it looks like I'll have to try understand a bit more about relativity before being abl... |
[
"What would a pipe organ sound like on planets with wildly different atmospheres than Earth's?"
] | [
false
] | I found and which both focused on the sounds of a pipe organ on Earth, Venus, Titan, and Mars. The pitch and effective propagation of the sound changed due to the atmospheric differences. I would like to find out more about this subject and predict what this same pipe organ might sound in more extreme environments such as the gas giants of our solar system or some of the exoplanets discovered by the Kepler telescope. I am a sound design student who is very interested in space and these concepts, but the physics and equations involved in the paper that I shared is not something that comes easy to me. | [
"Lighter gasses cause higher frequencies. heavier gasses cause lower frequencies. higher air pressures cause a higher speed of sound.",
"We have no working microphones near the surface of mars because all mics we send down broke or have been shut down early. But a few mars orbiters could hear good enough to hear ... | [
"The speed of sound is\n sos=sqrt(gamma*pressure/density) ",
"Gamma is cp/cv which depends which gasses you have in your medium. You can probably look up all three or just Google speed of sound Jupiter. You can calculate this and then find your change of pitch accordingly! "
] | [
"Yes I noticed the correlation and read within the linked paper what caused the pitch change. My question is what would the pipe organ sound like elsewhere; how would I calculate that? I can find atmosphere variables for other bodies but I literally don't understand the equations :/",
"Edit: there is a lot of non... |
[
"What's the highest frequency laser?"
] | [
false
] | I've been playing the game Stellaris which has a late-game technology you can research, gamma-ray lasers, which got me thinking about laser frequencies. The certainly makes them sound like a difficult research project, not something in production. The graphic they have seems to imply the highest-freq commercially available laser is pretty solidly ultraviolet. Are there higher-freq research laser, and if so, what are they used for? Is the trouble in producing higher frequencies finding an appropriate gain medium? If so, what research is there in finding such materials? If not, what IS the main obstacle? Further questions: if we had such a laser (gaser?) what would be some of the research, industrial, commercial, and military applications that we couldn't do with a UV laser? In particular, would this have applications in laser fusion? Also, searching this subreddit, I found , which doesn't sound that hard in the thread. Could this method, or some other method of raising a lasers frequency, other than the brute force approach of just accelerating the emitting device relative to the target, be used in production of a high-freq laser? How does this apply to the above? | [
"It depends what you mean by a laser. If it actually has to work through a lasing mechanism (involving population inversion and whatnot), the current limits are in the ultraviolet. I read a paper a few years ago claiming to get 10 nm radiation...I don't know if that's a record or what.",
"Above that there are fre... | [
"You're right that there are X-ray Free Electrons Lasers, although current only two are operational (LCLS, in Stanford CA and SACLA in Japan). They aren't quite the same as synchrotrons; the electron energy produced by those isn't high enough to produce coherent light, as it needs to propagate through the undulator... | [
"The DESY XFEL is online now too and going into user operations this year, I believe, and the FERMI soft-XFEL at Trieste has been up for a while. Also the XFEL at PSI is now working although not in user-use yet. "
] |
[
"Does the moon have a mantle?"
] | [
false
] | If it doesn't why does the earth? Do all planets have a molten core? If they don't what are the circumstances for having one? | [
"The moon does have a mantle and a small liquid outer core. ",
"All terrestrial planets have a molten core and mantle to some degree , as do the larger moons. ",
"The mantle and the core are hot due to radioactive decay as well as some residual heat from the formation of the planet. The moons of Jupiter are al... | [
"If by similar you mean made by the same element ratio, then yes more or less. Otherwise no. It is nowhere near the same relative size nor does it produce a geodynamo magnetic field. ",
"The magnetic field on the moon is very weak and is either due to the remnants of geomagnetism or from large impact events. "
] | [
"Follow-up, then: Does our Moon have a magnetic field? I assume its core is similar to ours, am I correct?"
] |
[
"Nocturnal Dinosaurs, evidence and how common?"
] | [
false
] | We have predators today that are nocturnal. We have raptors (more closely related to dinosaurs than reptiles). It seems almost certain there would have been nocturnal dinosaurs. Are there any studies or evidence of there being nocturnal dinosaurs yet or are we left to speculation and assumption? How common would it have been? What in the fossil record indicates whether a creature was nocturnal or not? | [
"Not many publications, and inference based on indirect measurement.",
"For example Michael Menaker applies principles of chronobiology to mammalian fossils in the following paper (using phylogenetic inference to determine the potential biology of extinct species relative to the overall groups they belong to, lea... | [
"No problemo. If I spot any other publications (got me interested in it frankly) I'll report here."
] | [
"Thank you."
] |
[
"Are Bill Nye and Neil deGrasse Tyson wrong on DeflateGate? Wouldn't a ball cooled from 80F to 50F be 2 psi under 13 psi?"
] | [
false
] | If a football had a (gauge) pressure of 12.5 psi inside at 80F and brought outside to cool to 50F what would its pressure be? I am asking because two science populists have publicly gotten this straightforward calculation wrong. has publicly stated a football to deflate 15% (note the accusation is 2 psi which is about 15% of the gauge pressure) it would need to cool from 125F to 50F. has said "Rubbing the football, I don't think you can change the pressure. To really change the pressure, what you really need to change the pressure is one of these – the inflation needle" . (Despite that rubbing the football can by friction warm the football, which by the ideal gas law would increase the pressure). EDIT: I should add that other people accept the physics argument from the Patriots correct. lists: Of interest, one of the professors in this article made the common mistake of forgetting to account for atmospheric pressure and calculated a ball cooling from 80F to 53 F would change from 12.5 psi to 11.9 psi (which is what you'd get if you didn't factor in atmospheric pressure. The mistaken calculation: 12.5 psi (53+459.67)/(80+459.67) ~ 11.9 psi. As for the Boston-area professors, could they be influenced by their football allegiances? They all said no. Naughton is a lifelong Buffalo Bills fan, but said, “My answers to any of these questions don’t change regardless of whether I’m a fan or not.” : Neil deGrasse Tyson and states a ball cooling from 90F to 50F would account for a 2 psi loss in pressure. | [
"I don't think you can assume constant volume here. The ball is elastic and the relationship between pressure and volume is almost certainly non-linear."
] | [
"I think the assumptions that the starting temperature of the ball was 80F and the end temperature of the ball was 50F can be challenged. ",
"Dropping from 85 F to 45 F would take a 12.5 PSIg football to 10.5 PSIg \n. That doesn't seem outside the realm of possibility. "
] | [
"This Youtube experiment",
" conducted by HeadSmart Labs shows that a football inflated to 12.5 PSI at 75 degrees loses 1.80-1.95 PSI at 50 degrees when damp, simulating conditions at Gillette Stadium last Sunday.",
"The coach of the Patriots says that a \"rubbing\" process performed on the balls shortly before... |
[
"Is there a limit to how loud a sound can be?"
] | [
false
] | For example, if I'm in a sealed room, is there a limit to how loud something could be in that room? Is there a different limit for different mediums? | [
"Sound waves are compression waves that propagate as deviations in the pressure of a medium. The amplitude of a sound wave is related to how much of a deviation in pressure there is in the sound wave relative to the \"reference\" pressure (the pressure inside the room when it is \"silent\"). Therefore, the loudness... | [
"Just a reminder for OP, db is a log scale. So the 15 db difference between a shot gun and \"ear-death\" is a whole lot ",
" than the 14db difference of the theoretical max."
] | [
"So above ear death we get to \"blow your skin off\" sound levels?"
] |
[
"What is actually going on with new COVID-19 variants and their mortality rate?"
] | [
false
] | There seems to be a new variant each week, which are being labelled as 'variants of concern'. I understand that they're usually related to the vaccination efforts and ensuring people will be protected against new variants, long enough for the vaccines to be tweaked when an inevitable, vaccine-resistant strain emerges. I'm not worried about that, because each of these new variants don't seem to fully bypass any of the vaccines yet. What I am worried about is some variants being reported as more lethal, for example the UK and California ones. I understand the news will use sensational headlines to catch people's attention, but shouldn't a virus start mutating to be dangerous? And if this isn't the case for coronavirus, will there be a peak mortality rate or will it continue to climb? | [
"The more people get infected, the more variants we will see appearing. It’s not the same having a 0,001% probability in a hundred cases than in a few millions. Generally, being less deadly and less noticeable means that one infected person will be able to spread the virus more before feeling sick and retreating fr... | [
"\"No evidence [yet] that vaccines reduce community spread\" is much different from \"evidence that vaccines don't reduce community spread\".",
"This is a difficult thing to study in a controlled way, and unethical given the ongoing pandemic, but ",
"observational data strongly suggest that vaccination with the... | [
"That's what viruses do. They tend to mutate frequently. It's random process. Some mutations make them more infectious and such viruses become more prevalent logically. Some mutations can make them more deadly (not that viruses have intentions) and some don't change much. Logically mutations that promote spreading ... |
[
"Considering that a mirror changes the direction of photons, is it actually \"deformed\" or even \"used up\" in the process?"
] | [
false
] | null | [
"Yes, it's accurate to say that a mirror will be subjected to a ",
"deformation",
" when a beam of light is applied. The reason is that photons have a finite momentum, and because the mirror changes the direction of travel (and hence the momentum) of the photons in the original beam, it itself must experience a... | [
"When photons lose energy, they reduce their frequency. So blue light might turn into red light. All photons go at the same speed in the same medium."
] | [
"That shouldn't happen. It will be very slightly dimmer and there may be imperfections, but it should look very much like the real world. Remember everything is twice as far away in the mirror. Maybe you need glasses. "
] |
[
"Can you absorb nutrients through the colon?"
] | [
false
] | So I have heard of "butt chugging" which is you putting alcohol in your anus and absorbing the alcohol through the bloodstream to get drunk. My questions are: Thanks for all of your help in my morbid curiosity! | [
"The short answer is, yes! To some degree you can absorb substances through the rectum, which is why many medicines are made with suppository formulations. Some things such as alcohol and water can also be absorbed. Anything that is absorbed into your body and metabolized, regardless of the route of ingestion, coul... | [
"I would add that the nutrients need to broken down (or digested) and need to be hydrophilic (fat would be very difficult) in order to be absorbed through the colon. A ",
"TPN",
" formula would be a good example of what state the nutrients need to be in. All fat soluble vitamins would not be absorbed (except p... | [
"I agree entirely. And yes, Bear Grylls is totally nutter butters."
] |
[
"can a butane lighter increase the temperature of aluminum to its heat of vaporisation?"
] | [
false
] | I ask because I ran into this thread I tried doing the problem my self, you know Q=(c)(m)(change in T), but I am a bit rusty in physics and some how wound up with an answer of change in T=154596198 kelvin, which is obviously not right. | [
"You're asking the wrong question. All you need to do is compare the temperature of the flame to the boiling point of aluminum.",
"From your links, the temp of Butane flame is like 3500C and the boiling point of Al is 2500. So YES, a butane lighter will certainly evaporate Aluminum! ",
"Fyi, the equation you po... | [
"I agree that temperature is the main factor, but with many issues about how realistic this is.",
"Aluminum is a pretty good conductor, so any heat you put in will rapidly spread out. So for this to work a very small piece of aluminum would help.",
"Then there is heat loss to the surrounding environment. Any co... | [
"ah I see, I should have paid more attention in physics, thank you"
] |
[
"A habitat is built on the moon: if we didn’t put down an artificial floor would air leak out through the ground under the enclosure?"
] | [
false
] | I doubt it would be fast, but would the ground act as a semi-vaccuum membrane of sorts? | [
"I'll disagree with ",
"u/chodpaba",
" with the caveat that I specifically only know about ",
" sciences. But so far as I know, the soils on mars and the moon are of a granular nature similar to the ones we have on earth, with little to no organic carbon components or water. On Earth there exists the ",
"va... | [
"Soil on the earth and regolith on the moon are porous. Air can travel through."
] | [
"Thank you for the reply. ",
"I should have clarified that this was a bit of a whimsical question influenced by ",
"this post in retro futurism",
". I just imagined atmosphere leaking out of the habitats in that picture and wondered whether vacuum can extract atmosphere slowly and indirectly. "
] |
[
"Need help translating Chinese publication. side note: chinese using HIV/AIDS in research!?"
] | [
false
] | So a hospital in China just published an article about spinal cord injury and I need to see what concentration of LiCl they used in transplantation. I tried skimming over the original document / / and could not find what I was looking for. Then I used google translator, and it completely botched the translation (columns overlapping). If someone who can read chinese could take a look over the article and let me know what concentrations of LiCl they used in vivo, I'd greatly appreciate it. SIDE NOTE: maybe it was google botching the translation, but I kept on reading things about HIV and AIDS. WTF!? | [
"It looks like they did a daily injection of 85 mg/kg intraperitoneally.",
"80 只大鼠随机分为 4 组,每组 20 只: (1) 脊髓全横断对照组(A 组, n=20): 仅行T9 平面脊髓全横断, (2) 氯化锂组(B组, n=20): 脊髓全横断+氯化锂(",
"),(3) 细胞移植组: 脊髓全横断+hUCB-SCs 移植(C组, n=20),(4) 氯化锂+细胞移植组(D组, n=20): 脊髓全横断+ hUCB-SCs移植+氯化锂.",
"80 rats were divided into 4 groups, each grou... | [
"I also saw HIV in there though. Then again Iraq was in there once or twice.",
"thanks for your help though!"
] | [
"I didn't Google translate the whole thing (only a paragraph to see what you were talking about), but other Chinese grammatical characters will also give you nonsense when put through Google translate (colon, comma, period, etc)."
] |
[
"Help me restore my faith in Maxwell's equations"
] | [
false
] | I have trouble wrapping my head around this... One of Maxwell's equations says that the eletric flux through a closed surface is proportional to the amount of charge enclosed by it. But I can imagine a case where that is not true. Suppose you have a uniform, nonzero charge distribution everywhere in the universe. Since all directions are perfectly symmetric with no preferred direction, I guess the electric field would be zero everywhere. So an closed box would have no flux through it but would enclose a net charge. Please help me understand the flaw in this. Thanks to everyone that responded. I think I have a better understanding. No boundary conditions and an indistinguishable scenario from an empty universe. It makes a lot more sense. | [
"s2 is just outside",
"o.O How did you know that.... ?"
] | [
"In brief: Integration by parts ",
" require knowledge of boundary conditions.",
"Luckily, in physics we don't need to be rigorous. We just need to be in agreement with observation."
] | [
"I only just read your username. My comment is just, well, stupid now."
] |
[
"Are spiders immune to getting stuck in their own webs?"
] | [
false
] | And/or does it matter with webs from other spiders? | [
"Spiders are able to generate two kinds of silk",
"—one sticky, one not. The spokes of the web are made from the non-sticky silk, and spiders carefully traverse their own web. In addition, ",
"tiny hairs and oils",
" on their leg, as well as how they grasp and release their web with each step, prevent them fr... | [
"Crazy... I’ve lived my entire life around a lot of spiders and never known this. Thanks for the great answer and link!"
] | [
"I don’t know about other spiders, but the shaker spider (aka cellar spider) makes messy tangled 3-D webs that can definitely trap other spiders. Once they’re trapped, the shaker spiders use their long legs to wrap their victims in silk, and then it is chow time. ",
"I generally don’t like spiders, but I used to ... |
[
"What determines the angle, length and curvature of a rainbow?"
] | [
false
] | Does is change depending on where you are in relation to clouds/water molecules? | [
"A rainbow is always a circle centered on the shadow of your head, the circle always has a radius of 42",
". The rainbow will be visible whenever water droplets are present in the right place and not blocked. ",
"It's always in that spot because that's where the refraction angles are correct for your particular... | [
"the circle always has a radius of 42 degrees",
"Eh? How is a radius measured in degrees? "
] | [
"Just like the stars are charted in the sky by their angle from the horizon or other features. The center of the rainbow is a particular direction opposite the sun (a ray from your eyes to the shadow of your head basically) and the rainbow appears in any direction that makes an angle of 42",
" with that center."... |
[
"Can an isotope have a negative number of neutrons?"
] | [
false
] | proton = upQuark + upQuark + downQuark neutron = downQuark + downQuark + upQuark A nucleus can be described by its number of upQuarks and downQuarks, if their positions are a blur. On the other hand, many videos show protons and neutrons as nonoverlapping balls, which I take to mean vibrations that attract and repel at various distances. Can a neutron and proton in the same nucleus swap positions? | [
"You cannot have a negative number of neutrons.",
"Can a neutron and proton in the same nucleus swap positions?",
"There are excitations of nuclei in which protons and neutrons vibrate back and forth, out of phase with each other. These are called isovector giant resonances."
] | [
"No! \nEven a nucleus with protons only could hardly exist. For example 2 protons together as 2,2He can exists for very very short time and next beta+ decays. So even with 0 neutrons is not stable at all. Something is needed to compensate the repulsion of positive protons. And as I see only 2 stable combinations of... | [
"Neutrons are a physical, countable thing. You can't have a negative number of neutrons the same way you can't have a negative number of apples. "
] |
[
"I'm reading about mu-metals and I had this question..."
] | [
false
] | Let's pretend I'm holding two magnets close to each other and I'm just barely able to counter the attraction. If another person sticks a mu-metal sheet (of size >> than magnet size) in-between the magnets do I stop feeling any attraction? or is it just that the mu-metal won't feel anything and the rest will go unaffected? Whatever the answer may be, can you suggest good reading on those high "mu" materials (other than wikipedia) ? They've piqued my curiosity... | [
"From my understanding you'd still feel an attraction, but instead of the magnets attracting each other, you'd feel the Mu-metal interacting with the magnets individually. ",
"If you got an old hard-drive laying around, rip it open take out the silver metal piece on the drive (",
"http://www.youtube.com/watch?v... | [
"Where is the mu-metal in a hard drive?"
] | [
"Well you got me, I don't think its actually mu-metal being used in everyday hard drives, but I am sure it's some kind of shielding and all magnetic shields work the same by providing the magnetic field a really easy path to travel through instead.",
"Well I get a chance, I'll certainly poke around to find out. T... |
[
"Why does hot water freeze faster than cold?"
] | [
false
] | [deleted] | [
"Basically - it doesn't. But if you leave the same volume of hot and cold water out the hot water will freeze first because 1) lots of the hot water evaporates, 2) the hot water shrinks slightly as it cools, so basically there's less water. You end up with such a smaller volume of water in the pot that was original... | [
"Check out ",
"this article"
] | [
"It can actually, it's one of the most famous experimental findings in physics because it was so against conventional wisdom, it's called the 'Mpemba effect' after the Tanzanian school kid who first discovered it in a school lab study on ice-cream in the 1960s. ",
"http://news.discovery.com/tech/water-freezing-po... |
[
"The video game \"Subnautica\" depicts an alien planet with many exotic underwater ecosystems. One of these is a \"lava zone\" where molten lava stays in liquid form under the sea. Is this possible?"
] | [
false
] | The depth of the lava zone is roughly 1200-1500 meters, and the gravity seems similar to Earth's. Could this happen in real life, with or without those conditions? | [
"Oh shoot! As a geoscientist and a huge Subnautica fan, I'm sorry to come in late on this.",
", the lava depicted in the lava zone is completely unrealistic (but ",
" cool.) Let me comment on the pieces of the answer that people have already given:",
"As ",
"/u/Little_Mouse",
" points out, real underwat... | [
"I can't speak directly to lava coexisting next to saltwater at depth, but there's some other misinformation thrown about this thread that I wanted to clear up:",
"Lava glows because of ",
"thermal radiation",
". This is linked with the concept of blackbody radiation, where matter emits electromagnetic radiat... | [
"The other possibility is that if the rocks are certain mixtures of lead and/or mercury and other low melting point metals, the lava could be much cooler than it is on earth. Some have melting points around 30 C."
] |
[
"Does light travel forever?"
] | [
false
] | Does the light from stars travel through space indefinitely as long as it isn't blocked? Or is there a limit to how far it can go? | [
"As long as it doesn't get absorbed by something, then yes, light will continue to travel indefinitely. However, due to the expansion of the universe that light wave will get stretched out along with the space it travels through, becoming lower in frequency and energy. This is why the Cosmic Microwave Background, w... | [
"There is no \"point where the big bang occurred\". It happened everywhere at the same time. The microwave background is the light released when the big bang happened, but the points we see it from were ~13.8 billion lightyears away, so it took this long for that light to get to us."
] | [
"There are definitely places that light will never reach, assuming that the expansion of the universe holds at a certain distance the other object is moving away from us faster then the speed of light (bending spacetime is the only thing that can go faster than the speed of light), so the light will never reach tha... |
[
"[Physics] What happens when light is absorbed?"
] | [
false
] | Follow-up question on the "what happens to the photons" question. No doubt probably one I should know the answer to. What actually happens at atomic level when photons get absorbed? | [
"The photon is destroyed and its energy and momentum are given to whatever absorbed it."
] | [
"But how exactly does it cease to exist? Like a bubble popping? Does it tear up into pieces? "
] | [
"The energy of a photon is given by E=hf. An atom consists of a positively charged nucleus, with surrounding electrons. These electrons can only occupy some discrete orbitals, each with its specific energy level, where the lowest energy levels are closest to the center. If the energy of the incoming photon equals t... |
[
"Why does my pulse feel \"stronger\" on an area of my body that I recently injured?"
] | [
false
] | By "stronger," I'm trying to convey that it feels much more noticeable. For example, I broke in some new shoes, yesterday. This caused a blister on the back of my foot, which burst and exposed the raw skin underneath. Afterwards, I noticed that sensation that the movie "Elf" described (rather well, actually!): "My finger has a heartbeat." | [
"Inflammation is a response to injury; and that inflammation is due to increased blood flow to get nutrients and materials to the damaged site. More blood flow is what allows you to feel the stronger pulse."
] | [
"Inflammation leads to increased blood flow - not the other way around. "
] | [
"I apologize if I was incorrect, I'm not sure which leads to which. Although the answer in jest does explain why the asker can feel their pulse more strongly."
] |
[
"My seven-year-old would like to know if gels have a \"skin\" (meniscus) like water does?"
] | [
false
] | null | [
"A meniscus is caused by the ratio of the strength of the cohesive forces of a fluids molecules to each other and the cohesive forces of the fluids molecules to the container wall.",
"If a fluid has a higher cohesive force attracting it to a container wall than the intermolecular forces then the fluid will have a... | [
"It has to do with surface tension, which tries to maintain the smallest surface area possible. Mercury has a high surface tension, so it tries to form itself into a sphere. The material also matters, if the liquid is more attracted to the container than itself (like glass and water, both polar) the liquid tries to... | [
"I was looking at a pressure measuring instrument in the lab full of mercury and remember seeing that the meniscus was inverted (i.e. convex upwards in the tube). Is this due to it's high density?"
] |
[
"Why do we get frustrated?"
] | [
false
] | [deleted] | [
"Just because we do it, doesn't mean there is an evolutionary advantage or that it is even related to evolution.",
"We get frustrated because we are inherently selfish beings who want to succeed. Failure to succeed or proceed at a pace we like causes frustration."
] | [
"Birds can get frustrated, for a certain definition of frustration. Parrots can redirect aggression on objects or other birds when prevented from doing something they want to do, and several shorebird species will get stressed about neighbouring birds being too close and vent their frustration by destroying inanima... | [
"Yes, think of it more like a consequence of our need to succeed. It's the pain we inflict upon ourselves to as a sort of \"punishment\" for not doing things right. It can be irrational, sure, but it's the result of our need to succeed."
] |
[
"Are hive insects incestuous? If so, how do they deal with inbreeding?"
] | [
false
] | A thought just hit me and got me wondering. Bees, ants wasps, etc. have one queen who produces all of the hive's offspring. I'm not sure how it goes with ants but IIRC with bees the queen regularly mates with drones. Are these drones that hatched from the queen's own eggs? Does this lead to inbreeding? Or do drones regularly visit other hives? Edit: Thanks for all the awesome answers guys! The same question really goes for flightless insects too. I'm guessint it'd be a lot harder for a male ant to go about and find a queen he's not related to have invertebrate sex with. | [
"Are these drones that hatched from the queen's own eggs? Does this lead to inbreeding? Or do drones regularly visit other hives?",
"The queen uses sperm from drones from another colony. But these drones do not fly over and visit the colony itself. The queen mates during one mating flight early in her life. Sperm... | [
"Actually, worker bees are females and are produced from fertilized eggs. Drones are produced from unfertilized eggs. In certain situations (a queenless hive), a few workers can start laying eggs but since they're not fertile eggs, the hive will eventually be filling with drones which leads to eventual loss of the ... | [
"They live to reproduce and eat honey. ",
"Sounds like my kind of life!",
"How does an unfertilised egg create an animal that can reproduce? That's the first instance I've heard of it in nature, is there some sort of unusual biology here or did I just not pay enough attention at school? An unfertilised chicken ... |
[
"Why does an infinitely-powered, constant-thrust spaceship never reach 300km/s?"
] | [
false
] | We have a spaceship that gets its energy in some unknown way, but it's essentially constant and unending and results in the spaceship not having to carry any fuel. With this energy, it can generate a constant amount of thrust indefinitely. The amount of thrust never varies for as long as the spaceship is traveling. A series of checkpoints is setup in space with each checkpoint 1 million km apart. Each checkpoint records when the spaceship passes by and transmits this time to all of the other checkpoints. The time is synchronized. The average speed of the spaceship is calculated by 1 million km / (end time - start time). The average speed between the first and second checkpoint is calculated to be 100km/s. The speed between the second and third is calculated to be 125km/s. Between the third and fourth, it's 150km/s. At this rate, it wouldn't take long before the spaceship will be going 300km/s. Yet that will never happen. I acknowledge that it's impossible for the spaceship to ever reach that speed. But there's no forces resisting the spaceship as it travels. It has unlimited fuel so that never runs out. It outputs a constant amount of trust, which would give it constant acceleration. Since it can never reach 300km/s, though, that means that at some point, the spaceship stops accelerating, even though none of the conditions have changed. Why? What physically keeps it from accelerating? EDIT: I recognize that variants of this question have absolutely been asked before, but those are invariably answered with variations of "frame of reference" or "not possible to have that much fuel" or similar. I have not seen an answer to this particular question anywhere in AskScience. | [
"Hi ",
"/u/az_liberal_geek",
",",
"it can generate a constant amount of thrust indefinitely",
"Sure, we can allow this. Let's pretend we have a constant thrust: our fuel is massless, the engine is perfect, and so forth.",
"It outputs a constant amount of trust, which would give it constant acceleration.",... | [
"The short answer is, as the spaceship gets to relativistic speeds its mass begins to increase, so the constant thrust results in less and less acceleration. Increasing the thrust won't help because as you approach light speed, the mass approaches infinity.",
"From inside the spaceship you wouldn't notice this ma... | [
"But let's say we are one of the observers at a checkpoint and have a way of measuring the mass of the spaceship as it passes by. Would the measurement show 1,224,321 kg?",
"It depends on how quickly that observer is moving with respect to the spaceship. If the observer shares an instantaneous comoving rest frame... |
[
"Does hot food provide more energy than cold food?"
] | [
false
] | Say I have two identical dishes, but one is hot and one is cold. Does the hot one provide more energy to my body than the cold one? I know the dishes have the same amount of calories in the food itself, but if heat is for this purpose energy, wouldn't a dish that is hotter than my body temperature disperse that energy to my body? If I'm in a room with a temperature below my body temperature, would this mean I get more energy from the food since the hot food provides heat rather than my body burning calories to generate body heat? Essentially, does this mean heating your food gives you more energy? | [
"It is true that eating hot food will lessen the calories your body needs to burn to maintain body temperature. The extreme would be drinking ice water which has no calories and would chill you, requiring you to burn calories.",
"But the effect is small. To raise the temperature from 0 C to 40 C, you need 40 ca... | [
"While completely factual, you are missing the efficiency factor for food intake versus heat generation in the human body."
] | [
"The question is not as silly as some people might think. Naturally it is true that warm food contains more energy than cold food. In a sense heating up 200 grams of food from 10 C to 60 C “infuses” it with about 10 kcal extra. That is not much though, and I would bet that in total the difference in effective energ... |
[
"Is there any trait or property that Earth lacks that would have made life even more likely to develop on it?"
] | [
false
] | [deleted] | [
"We know so little about how life actually started that it'd be mostly speculation to guess at what would increase the odds. That said, here would be some guesses:",
"Because we don't know how life forms or what stages it takes to get to something resembling a modern cell, it's hard to say if any of these things ... | [
"I believe the original question was about the probability of ",
" life developing on a planet. Maybe another kind of life than what we find here on Earth is more probable to develop its respective environment. Maybe another planet lacks some of the hurdles early Earth life might have had to go through. I don't t... | [
"There have been times in Earths history where Russia was indeed closer to the equator and probably had a lot of forests during those times. There are also periods where the Earth was in a hot house like the Paleocene and the Eocene. During times like these vegetation would be able to thrive with the increase in ca... |
[
"Why do computers sometimes move slowly?"
] | [
false
] | null | [
"I don't have time to give you the whole story but a common reason is that the computer is \"blocking\", is, waiting for a resource. Say you have two programs running, and both need access to the hard disk. The disk can only change one thing on the disk at a time and it takes time to move the head from one place to... | [
"I don't mind that it's not the whole story. I appreciate your response. I've always wondered what it was - in relatively simple yet still sophisticated terms - what's actually going on inside the computer when poor old MacBook has the spinning rainbow wheel."
] | [
"The real mystery for me (I am a software engineer) is how software keeps track with hardware in keeping computers slow. My slow laptop is a supercomputer from 20 years ago, yet it still takes six seconds for the unity main menu window to display on the screen. I got better subjective performance out of a PDP 11/84... |
[
"When losing weight, how does the body choose where to pull fat from?"
] | [
false
] | null | [
"When we burn fat our fat cells start turning the fat they store into fatty acids which can then be transported by our blood causing the fat cells to shrink. The fatty acids don't come from one specific place, all our fat cells start pumping out fatty acids. How much comes from specific area is determined largly b... | [
"If I understand you correctly then no I don't think so, excess visceral fat (fat stored inbetween your organs) does tend to get burned up first though. Your body also maintains a thin layer of fat directly under your skin that you only tend to lose under severe malnutrition, it's more kept as insulation than as en... | [
"Does the surface of the fat store matter? ",
"Bit hard to explain I guess but would you lose more fat in area's that do not have surrounding fat? I mean let's say if you have a lot of belly fat, would the \"inner\" most cells of your belly fat release less fatty acids then the ones more closer to the skin / in... |
[
"We often hear that the majority of the ocean is unexplored. Are we trying to change that and if so, what are we exploring and finding?"
] | [
false
] | As the title says. I've often heard that we know more about the moon than we do our own ocean. Are we actively trying to change that and if so, what are some of the exciting projects ongoing which are giving us some new insights in the oceans. | [
"We are literally ",
"live-streaming",
" right now from the bottom of the ocean, from hydrothermal vents on the East Pacific Rise. There are often live events like this, check out ",
"Nautilus Live",
" also some time, from the Ocean Exploration Trust.",
"There is a big push to map, explore and characteriz... | [
"Then why do I hear that asserted in many reputable documentaries? ",
"Because its a good sound bite and its a vague enough claim it can be made without factual evidence either way to back it up or refute it on the part of ocean advocates."
] | [
"If you can provide examples of what you describe I would be happy to address them. It's what I do, and the firs time I went to the bottom of the ocean was in 1992.",
"I too hear reputable claims there are better images of the surfaces of the moon and mars than the bottom of the ocean. This is true, and I don't a... |
[
"AskScience, what part of Earth has the smallest average temperature range? What part has the most hospitable temperature range?"
] | [
false
] | Obviously, all parts of the globe have fluctuating temperatures, and "hospitable" is somewhat subjective. I'm curious about places that don't change much or stay in a comfortable range. | [
"I'm not going to try and answer the part about 'most hospitable' -- humans live all over the planet, and people express preferences for tropics, mid latitudes, or snowy climes. ",
"Average temperature range, though, I can do. Using the NOAA land temp ",
"data",
", I made a map of the areas of the globe with... | [
"Thank you, thank you, thank you for delivering. Have some gold!"
] | [
"Awesome! Thank you!"
] |
[
"Is it possible to measure a liquids specific gravity in space?"
] | [
false
] | Or how is the density of small objects determined without gravity? | [
"Inertial mass is the same as gravitational mass, so you can measure the mass of something in space by, say, spinning it around and measuring the resulting centrifugal force."
] | [
"If you were to fill a container (of known mass, or mass you determine using the following) with that liquid, then attach the container to a spring of known spring constant, and then set the spring into motion (ie pull the mass a bit away, then let the mass oscillate), you could determine, from the motion of the sp... | [
"In the analytical labs best equipped for specific gravity of liquids, a digital densitometer of the ultrasonic type is employed to routinely determine precise measurements of liquid density.\nDensity varies inversely with temperature for liquids over almost all ranges, so both density and specific gravity need to ... |
[
"How do radio stations know how many receivers are listening to them?"
] | [
false
] | null | [
"They don't.",
"They do a poll.",
"They look at a map and say \"there are 3.5 million people in the area where they can easily listen to this radio station, let's call 3,500 of them and ask them if they've listened to the station in the last week.\"",
"So they do it, and they find out that 173 of the 3,500 pe... | [
"Nevertheless, that's how it's done.",
"Here's the Wikipedia article on the dominant polling company for TV viewing in the US and their system:",
"https://en.wikipedia.org/wiki/Nielsen_ratings",
"Note that it's a little more complicated than just a phone call - they have people either keep diaries of viewing ... | [
"And yet I have never been polled for this and I don't know anyone who has. ",
"I got called by Nielsen about 6 months ago and they mailed me a $5 bill for answering their survey, so now you do know someone."
] |
[
"Why do electrons have a \"negative\" charge?"
] | [
false
] | I am reading an electronics textbook and it is talking about the confusion around electricity flowing from a positive charge when it is actually electrons flowing from a more negative charge. I've taken a few chemistry courses in college so I get the basics of protons, neutrons, and electrons. What I am curious about is this: why is the electron's charge negative? In my eyes, a negative charge is just the name for the opposite of a positive charge, and it is just a name. Is there something in the mathematics describing these particles that force a proton to be called positive and an electron to be called negative? | [
"No, it's just an arbitrary convention. The signs of the electric charges of the electron and proton must be opposite, but which one calls positive and which one calls negative is a matter of historical accident."
] | [
"Like how it would make arithmetic just that bit easier if we counted in base 12. Oh well."
] | [
"I can't answer your exact question, but the reason your electronics textbook says current flows from positive to negative is because (according to my high school physics teacher and Wikipedia) Benjamin Franklin, who kinda pioneered studies on electricity, believed that. Now, we know that it's actually electrons be... |
[
"How can locks (as in door locks) or anything that requires a unique part be mass produced?"
] | [
false
] | I know some cheap locks only have a few unique keys and are just randomly sorted to give the illusion that they are unique. But how can locks that are expected to be at least moderately secure be mass produced while keeping every lock's key different? | [
"It doesn't take much variation to produce many unique locks.",
"The equation is:",
"Combinations = (unique pins) ",
"So if your locks use 6 pins and you make 10 different pin sizes then you can make 10",
" = 1,000,000 unique locks.",
"If you move from 6 pin lock design to a 7 pin lock design you can make... | [
"I suspect that in olden times a key would be cut with a set of moveable dies, inserted into the barrel, then pins would be inserted in the holes and cut flush. Nowadays they probably have pre sized pins and a computer will insert the correct pins to match the key",
"Combination locks have notched disks that have... | [
"To add on, car manufacturers don't make unique keys for each car. There might only be a couple hundred or thousand different keys for a particular model (meaning that your key has several twins). That's one of the reasons so many are going to completely digital systems, so you can make each individual \"key\" uniq... |
[
"If you're travelling at 0.99c, would you still observe light moving away from you at c?"
] | [
false
] | EDIT: Thanks, I thoroughly enjoyed reading this discussion! | [
"Yes.",
"Also, remember, there is no such thing as \"travelling at .99c\" in the abstract; you might be moving at .99c relative to me, but you will experience yourself being at rest and me moving at .99c relative to you."
] | [
"Yes, you can continue that process indefinitely. And there would be no observable difference between any of the steps of the process. If you couldn't see the stars or the people you left behind, there would be no way to know how many times you had sped up. That's a very important feature of space and time, that it... | [
"Yes, but instead of a .99c boost taking you from .99c to 1.98c, it would only take you to .99995c. That's what I mean by forces being less effective: the ship would be using the same amount of force for each boost, but it doesn't result in the same speed increase (relative to earth). But it always changes the spee... |
[
"Why don't batteries get drained instantly when shorted?"
] | [
false
] | Hi, I am starting to learn some electrical science and there is one thing that is confusing me. Each battery is rated for a limited amount of current hours (more geerally watt hours but the voltage stays constant so it doesn't really matter). The resistance of a short length of wire is incredibly small. This then means that the current will also be extremely high, since current is voltage over resistance. What I don't understand is why the battery doesn't instantly die when shorted. At first, I thought it was internal resistance, so I meassured the current through the contacts of a nine volt and got a value around 1 microamp. In my mind this would mean that the internal resistance is massive and the battery should be dead, but I put an LED on it and it lights. Am I measuring the current wrong? What prevents batteries from instantly draining when shorted? | [
"EE Here.",
"You're correct its internal resistance. Think of the real life battery as an idealized battery but with an internal resistor added. The resistor limits the current and prevents the ideal battery from draining immediately. Not sure I follow the experiment you tested that resulted in a microamp - thats... | [
"Your mental model is that a battery is essentially a box of voltage: there's a whole pile of electrons available on one terminal and a paucity of them on the other. They're just waiting for a connection in order to rush over and equalize the potential.",
"This is what a ",
" is like, but not batteries. Batteri... | [
"You check the change in the voltage drop as you linearly increase the current. The internal resistance will cause increasing levels of voltage drop as the current increases."
] |
[
"How fast is the earth moving in relation to the center of the galaxy? Does that speed vary?"
] | [
false
] | null | [
"If the earth is 30 000 light years from the galactic centre and a ",
"revolution",
" takes between 225 and 250 million years it would make it's speed somewhere between 225 km/s and 250 km/s (kilometers per second). ",
"http://hypertextbook.com/facts/2002/StacyLeong.shtml",
"http://www.wolframalpha.com/inpu... | [
"Current estimates",
" are that the solar system has an orbital velocity of 251±15 km/s around the center of the Milky Way, and the Earth orbits the sun at about ",
"30 km/s",
". This means that depending on where the Earth is in its orbit, it can be moving either 30 km/s faster or slower relative to the cen... | [
"That can be calculated:",
"T=To*γ where γ is the lorentz correction, γ = 1/sqrt (1-v",
"that would be 1/sqrt(1 - 552",
" = 1/sqrt(1-304704/90000000000) = 1/sqrt(1-0.0000033856) = 1/0.99999830719 = 1.00000169281",
"So that movement basically adds 53.4 seconds every year, or one full day every 1618 years.",
... |
[
"How exactly does histamine improve tourettes?"
] | [
false
] | There was a study on mice recently that confirmed an earlier idea of histamine playing a role in tic behaviors. They've injected histamine directly into "striatum" to observe the effect. Stupid question - could you emulate the effect simply by consuming "histamine-rich" foods? Or would the mechanism be entirely unrelated? Thanks. | [
"Med student here. Lots of neurotransmitters come into play with every aspect of our psyche and mental status. Histamine definitely plays a role in this, as evidenced by the sedative effect of anti-histaminergic drugs (Diphenhydramine). I can't speak to this new study that you mentioned, but I can answer your secon... | [
"A report about tourettes study was published by a group of specialists from the Yale School of Medicine leded by Matthew State in The New England Journal of Medicine.",
"During the investigation, the scientists studied the hereditary information of family members in which Tourette's syndrome suffered a father an... | [
"Well, maybe neuroscientists will find a way to inhibit the reuptake of Histamine, in a similar way SSRIs do to Serotonin. Or increase the production on neurons. \nOr maybe associate a lipophilic histamine that is able to cross the blood-brain barrier with an anti-histaminic that can't. "
] |
[
"Is E=MC² just a logical extension of F=MA with a different definition of terms based on discoveries unknown to Newton? ..."
] | [
false
] | or is it an equation which though seemingly similar describes a fundamentally different physical event? I know this may just be a pedantic question but it interests me nonetheless. | [
"E=mc",
" is a simplification of the full equation which contains a momentum term. That momentum term would better relate to MA, since an applied force over a given time would give you an impulse, or change in momentum. The mc",
" term describes the equivalent energy in a given mass at rest, which doesn't hav... | [
"No need to retract the question, it was a good one. I'm an engineering student and every day I find myself seeing similarities in equations and trying to find out if they're related. Thats how a lot of the equations we have now were created, someone saw two separate equations and made some connections."
] | [
"You remember newton's expression for the kinetic energy?",
"E = 1/2 m v",
" = 1/(2m) p",
"Well, this quantity is not really conserved in the relativistic limit. For very big velocities, the actual energy of the system must be written as:",
"E",
" = (mc",
" + (pc)",
"And in the slow velocity limit, it... |
[
"Does the asthenosphere actually exist?"
] | [
false
] | I have been recently told (by high-school teachers, for what it's worth) that apparently geologists don't think the asthenosphere is a thing anymore. Having been through uni over 10 years ago, I could very well be out of date, but honestly, it came as a shock to me. | [
"I have no idea what they’re talking about. I teach tectonics at the university level and have not heard of this being a thing. There’s not exactly a source for demonstrating that the asthenosphere is still considered to be real, but there are hosts of papers published within the last few weeks that are still discu... | [
"There are certainly lots of outstanding questions related to the asthenosphere, e.g., how best to consider the lithosphere-asthenosphere boundary, percent melt in the asthenosphere, amount of hydration of the asthenosphere, details of its rheology, etc, but that's different than rejecting the concept of the asthen... | [
"I know! I can't find anything either (at least in English, I found a Spanish paper called something like 'Goodbye to the asthenosphere' but it didn't say anything of use, basically that the asthenosphere is bad science). But they're so vehement about it! It made me feel like I know nothing at all."
] |
[
"Why do we like to destroy things?"
] | [
false
] | null | [
"to be honest you'd probably get better and/or more responses in ",
"r/psychology",
"."
] | [
"Maybe even ",
"r/askphilosophy",
"?",
"As a layman, I fully believe the \"destruction as a form of creation\" thing. People like to be creators of something, make things change, and destruction is an easy way of accomplishing this."
] | [
"That's just saying 'we like to destroy things' using different words. ",
"He asked why."
] |
[
"Do you have any stories about interesting/promising experiments that worked in the lab but not in the real world?"
] | [
false
] | null | [
"If you have some agar, you can show that many bacterial species cannot grow well on agar plates impregnated with various spices like garlic and cinnamon. Some things in those spices are antiseptic. However, like your example, it's all in vitro - these spices do not have curative properties, because they are dige... | [
"My favorite is the ",
"Viagra",
" story.",
"It was initially made as a treatment for high blood pressure, and made it all the way to clinical trials. During the trials, it turned out to be completely ineffective at controlling blood pressure. However, the patients in the study noted that they were all gettin... | [
"I guess a couple of people mentioned it then everyone would have been like 'shit me as well'"
] |
[
"Could you theoretically use the DNA from two sperms or two eggs to clone/create a human being?"
] | [
false
] | null | [
"You can do it with two eggs. Two sperm is a bit harder, since you'd need to grab an X chromosome from somewhere (YY would not be viable)."
] | [
"I mean, half of the sperms are X chromosome while the other half are Y, are they not? ",
"Couldn't you just grab one or two sperms that are X chromosome to complete the process?"
] | [
"Yeah sorry, I sort of thought myself into a corner there. You should be able to do it, although the sperm would be a little more difficult, since you'd need some 'normal' sized cell to put the genetic information into. Sperm are reduced cells, with reduced/missing organelles, so you'd have to basically remove the ... |
[
"Do plants have stem cells and do they recombine their genes?"
] | [
false
] | These are two questions: Firstly do plants (if this is too general: trees) have stem cells, and if yes where are they located? Secondly does genetic recombination happen with plants, too? E.g. if two plum blossoms are pollinated by one same bee carrying the polls of only one other plum tree, are the developing plums genetically identical? Putting all hopes on you guys, as my biology teacher couldnl not answer them. | [
"Yes, in plants growth and the start of new plant organs takes place at cells called ",
"apical meristems",
". Generally there is a shoot apical meristem for shoot growth and a root apical meristem for root growth. Lateral branches often start with their own shoot apical meristems.",
"But that is just for g... | [
"For your second question, yes, genetic recombination does happen in plants. They have a slightly different life cycle to animals but they undergo meiosis in the same way to produce haploid spores. So the pollen and egg in flowering plants have come from meiosis and would make the new plants genetically different."... | [
"Thanks for the detailed answer, any knowledge on recombination concerning plants? "
] |
[
"A black hole that forms from a star collapse stores more information on its event horizon than was contained in the original star. Where did the extra information come from?"
] | [
false
] | In class we learned that event horizons basically store and grow with information. We also approximated the information stored in a black hole in relation to its mass/size. We were told that the amount of information stored in a black hole's event horizon is actually greater than the total information of the star that it originated from. Is this true, and if so, where did the extra information come from? | [
"You're discussing the ",
"Bekenstein bound.",
" Essentially, consider a box with entropy/information S. If you try to reduce the volume of that box below a certain point (Schwarzschild radius), it collapses into a black hole. From that point on, you cannot compress the box further for any action you do to it a... | [
"Information, like energy, cannot be created or destroyed.",
"This requires a settlement of the black hole information paradox aka how pure states can become mixed as well as a settlement on the nature of what wavefunction collapse really is."
] | [
"Is this true, and if so, where did the extra information come from?",
"The current mainstream theory is that the \"surface area\" of the black hole is proportional to the amount of information \"inside\" the black hole. ( ",
"https://en.wikipedia.org/wiki/Holographic_principle",
" ) In other words, the \"am... |
[
"Can you (roughly) determine the dosage of a drug taken based off of the blood concentration?"
] | [
false
] | I do know there's no exact science for this because so many factors. Bioavailability, liver/kidney issues, weight, etc.. But say if an autopsy shows 0.33mcg/ml of blood for a certain substance.. Is there a way to reverse calculate what amount of the substance was taken? My best guess would be to get the persons weight and figure out how many L of blood they have and just multiply backwards. Again, I know there is no possible way to "accurately" determine how much was taken, but is there a rough way to guesstimate? Thank you EDIT - I want to thank everyone for their responses and overwhelming support. I really appreciate all of you. As I figured, it isnt as straightforward as I thought and there are so many factors in play here. | [
"In a criminal justice context, an expert toxicologist's opinion is often in the form of whether the concentration in the blood is \"consistent with a therapeutic range.\" ",
"So, for a given medication, there will be studies that say something like (just some random numbers here) \"this medication is usually di... | [
"Very good explanation. Thank you."
] | [
"A single sample? No. Multiple samples? It depends. When dosed, the concentration in blood rises for a period and then declines as it is metabolized and cleared from the body. Each drug has a sort characteristic curve for the drug and it’s metabolites that you could compare to a series of samples taken over time wh... |
[
"How can a single speaker make multiple notes at the same time that aren't on the same fundamental? (like a diminished chord, or a symphony"
] | [
false
] | null | [
"You're having trouble because you're confusing two different representations of sound. A speaker produces an arbitrary (within limits) pattern of air pressure versus time. A \"note\" is a particular pattern of air pressure versus time. We like to talk about \"pitch\" and \"timbre\" of a sound, and those qualiti... | [
"consumers who just listen to music typically want speakers that color the signal to boost certain frequencies",
"In other words, (bad) speakers. :-)",
"Edit: I think you made a good point, sorry if my glib response helped trigger some downvotes."
] | [
"But a (good) speaker is specifically designed to not resonate at all -- an ideal speaker selects no tones at all, so if you feed it an electrical signal carrying white noise (like the white noise you feed to a flute), you'll get out a sound that represents exactly that white noise.",
"That depends on who the end... |
[
"Why does a liquid having zero viscosity allow it to climb up and out of containers?"
] | [
false
] | null | [
"Great question! Even regular fluids can creep up the edges of a container a little thanks to capillary action. As you can see in ",
"this cartoon",
", if the surface attracts the liquid then gravity will be offset by these attractive forces a bit and the level of the liquid rises. If the surface repels the liq... | [
"Gravity pushes all fluids to the bottom of their containers. This puts pressure on the fluid which is relieved whenever a route is available. In zero viscosity fluids, that fluid pressure can be relieved because the attraction from the capillary effect can be stronger than gravity on an individual particle. Additi... | [
"It must overcome the force of gravity in order to climb up the wall. Where does that energy come from? If you let a superfluid climb up an arbitrarily high wall would you see its temperature decrease? "
] |
[
"Can photons be counted?"
] | [
false
] | Would it be possible to send out exactly 100 photons with different energies, and then measure exactly those 100 photons with the same energies at the receiving end? Or are photons just a unit/discretization of the EM field? | [
"Yes, we can detect single photons. The kinds of detectors we can use include things like ",
"single-photon avalanche diodes",
" or ",
"superconducting nanowire single-photon detectors",
". Such tools are not even that exotic and are routinely used in optics when you need to do photon-resolved measurements.... | [
"It's worth pointing out that ",
"the rods in our eyes can actually detect single photons",
". Though, our eyes are set to only signal our brain if we get about 9 or so of them."
] | [
"Though, our eyes are set to only signal our brain if we get about 9 or so of them.",
"Which is still low enough to get you random \"noise\" when it's dark, illustrating why firing for every single photon would be useless."
] |
[
"Do people in wheelchairs suffer from deep vein thrombosis more often than other people?"
] | [
false
] | null | [
"I'm at work and can't link any references right now. But, in short, yes. They are at a much higher risk of developing a clot in their lower extremities due to venous stasis. The blood in your veins isn't propelled by the pumping action of your heart - it is pulled towards the heart everytime you inhale or, in your... | [
"Why do compression stockings lower the risk? "
] | [
"It pushes the blood back up toward the heart. Essentially compression stockings are \"contracting\" because the muscles are not."
] |
[
"Is there an optimal ratio between iPod volume and car stereo volume in terms of sound quality when listening to an iPod in the car?"
] | [
false
] | I have noticed that different volume level ratios sound different to me in my car. I tend to turn up my iPod volume all the way up or close to max, and then just control the volume with my car volume knob. What is the science behind this? What would be the best strategy to take in order to improve sound quality? | [
"For the best quality, turn up your iPod until it starts to cause distortion. Then, go a little below that. This will give the stereo's input the highest dynamic range and a better SNR to work with. If you have some bizarre effects or non-additive noise, there could be problems, but generally, it is best to amplif... | [
"Assuming that you are using an AUX cable or a tape adapter (as opposed to a Bluetooth connection), put the iPod at quarter-to-mid-range, and control with car volume knob from there.",
"What's going on is that with the iPod volume set at max, you are losing some fidelity on the high end of the loudness (aka, your... | [
"No single component should be above 80%, generally speaking, that is when it starts flattening frequencies when increasing volume.",
"Disagreement usually starts coming in when there are people who know more about specific pieces of equipment. In this case, assuming that the iPod and Car Stereo are both fairly a... |
[
"Is there any difference between -1G, and being upside down?"
] | [
false
] | null | [
"It's not difficult to answer at all. I'm pretty sure lw421 is aware of the difference between zero net acceleration and -1G acceleration.",
"The answer is: No, there is no difference. An acceleration of -1G in the 'up' direction (i.e. the direction from your feet to your head) would feel the same as 1G in the 'd... | [
"You may be getting at one of the concepts of the ",
"Equivalence principle",
". Namely that the gravitational \"force\" as experienced locally while standing on a massive body (such as the Earth) is actually the same as the pseudo-force experienced by an observer in a non-inertial (accelerated) frame of refere... | [
"This question is difficult to answer, because it is not very well defined. If you have a ",
" acceleration of -1g applied to you, you would fall \"up\", away from the Earth. If you found that you had something to stand on, say, a floor, the external forces on you would lead you to think that everything was norm... |
[
"If the Apollo program had continuousely failed, how much longer would it have taken the Russians to get a man to the moon?"
] | [
false
] | Let's assume the space race wouldn't have ended and NASA would have kept failing. Sorry I post this a 2nd time, but it didn't appear in the new queue for a few hours the last time and I don't think a lot of people saw it. I would be really interested in an answer and didn't find anything. | [
"About 20 hours before we landed on the moon the russians had launched and landed an unmanned space vehicle on the moon. Don't think it was able to return to earth... they just wanted the title of landing something safely on the moon before we did.",
"I would guess that if there were still that race to do it and ... | [
"Don't think it was able to return to earth... they just wanted the title of landing something safely on the moon before we did.",
"That wasn't the first successful landing on the moon though. The first successful soft landing is ",
"Luna 9",
" in 1966, three years before. The US then later launched ",
"Sur... | [
"http://www.fas.org/spp/eprint/lindroos_moon1.htm",
"TLDR: They were not that far behind, but Korolyov died prematurely and they had a series of failures due to political dumbassery.",
"You could have just googled \"soviet moon landing\"."
] |
[
"What would I see with the naked eye if I was half-way to Andromeda?"
] | [
false
] | So I know that today's astronomy photos aren't like regular photographs: they have long exposure times and the colors aren't exposed the same way the eye would see them. So I'm wondering if the human eye would ever be able to see anything like what the hubble telescope saw when it took the photo. If I was in a completely dark spaceship half way between the Milky Way and Andromeda, would I be far enough away from interfering light sources to look out the window and see an array of galaxies with my own eyes? What would I see? | [
"It would look twice as big and four times as bright. So what does that mean? Believe it or not, the angular width of the Andromeda Galaxy (from here) is about 2 degrees. That's four times the apparent size of the Sun or Moon. The reason why we can barely see it is because it's so dim. It's got an apparent mag... | [
"Well first - the colors in the photo depend on the frequencies taken and any post processing done. Lots of the photos are indeed in the visual range and generally minimally processed - so they do represent the real colors. Obviously IR, UV, Xray, etc... are false colored (as are specific filtered photos, such as... | [
"The problem with dust is that even if you are in a fairly dust free area - the closer you get to the galaxies the duster it gets (therefore, you are looking through dust at the galaxies).",
"You might see galaxies besides the two big ones - depending on their locations etc - You won't see the deep field because ... |
[
"Is the size of DNA proportional to the complexity of the organism?"
] | [
false
] | null | [
"Generally, no",
".",
"This observation was originally referred to as the \"C value paradox\", as people thought it didn't make sense that there was no relationship between DNA content and perceived organismal complexity. The resolution comes chiefly from the fact that most DNA in most genomes (and especially t... | [
"It's also not easy to rank organisms by complexity. Which is more complicated, you or a crayfish? You're physically bigger and you have a big brain and all, but your life cycle is really basic and you only have four limbs.",
"You can try ranking number of coding genes but a few chunks of the noncoding regions ha... | [
"It's also not easy to rank organisms by complexity",
"Exactly, thus my careful choice of the word \"perceived\" complexity."
] |
[
"How long will the astronaut's footprints on the moon really last?"
] | [
false
] | We've all heard the footprints on the moon will last many millions of years, until they're eroded by micrometeorite collisions, or moonquakes, or the like. But I once read a suggestion that the constant monthly cycling of the lunar regiolith from daylight to darkness, from hot to cold might make them disappear far faster, due to the expansion and contraction of the particles in the dust. Has anyone else heard of this? How long will man's footprints on the lunar dust really last? | [
"This question is probably worth a what-if.xkcd.com, but I'll give it a Fermi estimate shot (Ignoring anyhting about regolith moving, because I have no idea about it and it feels \"wrong\" to assume the effect is large...): I'd say the biggest chance of disturbing a footprint is via shaking due to a nearby asteroid... | [
"Let's postulate using snow as an example. Not accounting for melt, let's assume the temperature remains constantly cool. ",
"Footprints generally expand in snow first and for quite a while as the geological motions and rays of light apply very small amounts of energy. This is similar to the slow geological motio... | [
"Yeah, I was likening the forces of the moon acting neutral to the footprints, as I made the bit tortured correlation between footprints on earth versus footprints on the moon. I suspect it would be far less amplified (sun rays reflecting equally across the surface of snow is somewhat different to electrostatic lev... |
[
"How do viruses cause illness?"
] | [
false
] | [deleted] | [
"Viruses exist in a weird biotic space between living and non-living. That is, they do a lot of the things that living things can do, but there are a couple things they cannot do. Most notably, a virus cannot create other viruses. Instead they rely on the machinery of a host cell to make viruses using their viral g... | [
"Right, so it is sorta how it popped up in my head, it's possible to be pandemic due to the lack of resistance, like diseases in our own past, but also possible to be ineffective, due to it's own evolution following a path that is two dissimilar to even allow infection. "
] | [
"Yes, similar to introducing a species into a novel environment. It might not survive, or it might survive too well and take over everything else.",
"I'm inclined to say that it's less likely to take over given the huge adaptive disadvantage, but I'm sure there's someone out there who knows way more than me and w... |
[
"How \"mobile\" are bacteria and viruses on dry skin?"
] | [
false
] | It's flu and cold season so I'm curious about a few related things. Assuming dry hands and dry door knob or similar surface: How easy is it to transfer bacteria/viruses from the surface to your palm/front of your fingers? If you touched the surface with the back of your hand, can the germs easily make it around to your palm and front of your fingers (where they are more likely to get into your mouth/nose)? My rationale for the second question is really wondering whether opening a public door with some other part of the hand/arm can help prevent illness. Thanks! | [
"Someone correct me if I'm wrong, but I think that bacteria/viruses spread easier when there is some \"wetness\" involved. It's why if you drop some dry food on the ground, the 5-second rule is o.k., but if the food or ground it lands on is wet, you shouldn't eat it at all.",
"You won't feel the flu symptoms imme... | [
"The 5 second rule isn't science, its just an excuse people give so they are not wasting food. The vast majority of dirt, bacteria etc will transfer to the dropped object instantly. That being said you are very unlikely to get sick just from eating dropped food unless you dropped it on a rotting carcass or somethin... | [
"Skin-object contact transfers potential pathogens pretty easily, in both directions, even if your skin feels dry. However, there's negligible \"traveling\" across the skin, so yes, using your elbow or similar to open a door instead of your hand is generally a pretty good practice re: preventing exposing yourself ... |
[
"How come when you have been wearing a hat/sleeping/etc. your hair gets stuck in a postion making \"bed-head\" or \"hat-hair\", and stays like that until it is made wet. Why does water fix it, what effect does water have on hair? Why can't you put the hair back into place without water?"
] | [
false
] | null | [
"It is to do with Hydrogen bonding / the heat generated by close currents of heat between the hat and your head. Your hair is made of keratin and that keratin protein contains amino acids (mainly cysteine for disulphide bonds creating ''hard'' keratin strength), hydrogen bonds and side chain linkages. Proteins unde... | [
"Thats actually really cool!!! Thanks!"
] | [
"No problem. Me and my friend were curious the other day so I had decided to discover the properties of Keratin so this is clearly close to my heart."
] |
[
"How can someone become more intelligent?"
] | [
true
] | [deleted] | [
"You need to be very specific about what you mean. Intelligence can be broken up into a lot of different faculties."
] | [
"You need to be very specific about what you mean. Intelligence can be broken up into a lot of different faculties."
] | [
"This is an extremely topical question. Briefly, we believe there is a neurobiological substrate for fluid intelligence. If that is definitively true, there may be methods which may improve fluid intelligence by targeting that neurobiological substrate - either by training, or by other intervention.",
"For exam... |
[
"Are solar panels as effective on mars, further from the sun, and with less atmosphere?"
] | [
false
] | null | [
"If the question is, would the same panel produce less power on mars than on the earth on a clear day (assuming for a minute that both measurements are made at on the equinox at nooon and on the equator), then the answer is yes. While its true that on earth we lose some solar irradiance to absorption in the atmosph... | [
"On the other hand, Mars has a completely different climate with far fewer snowstorms, so while under optimal conditions solar panels on or near Earth will be more effective, under average conditions, panels on the surface of Mars may be comparable or even more effective."
] | [
"thank you"
] |
[
"If you live an incredibly healthy lifestyle but smoke cigarettes, are they as bad for you as they would be for an un-healthy person smoking?"
] | [
false
] | null | [
"Many studies have controlled for other lifestyle choices. Smoking is very bad for your health, and most of the really bad stuff happens between age 60 and age 70. Obesity is not a risk factor for lung cancer, for example. But for coronary heart disease, both smoking and obesity are risk factors, and perhaps smoki... | [
"It's a little like buying a lottery ticket. Any given lottery ticket might just be the one that wins the jackpot, but the chance of a single lottery ticket winning is extremely tiny. However, you could theoretically buy a single lottery ticket, a single time, and win. You could also buy 1,000 tickets a day and nev... | [
"Today on \"Hey Kids, Try Some Cigarettes:\" If you're under 35 years of age, quit before you're 35 and you'll have negligible long-term effects. 35 to 45 is almost as good, after 45 it gets a bit dicey.",
"Source? THE NEW ENGLAND JOURNAL OF MEDICINE\n",
"http://www.nejm.org/doi/full/10.1056/NEJMsa1211128"
] |
[
"Are these lights safe to use?"
] | [
false
] | I'm interested in induction lighting because of the wattage/great benefits for my green house during the winter months. I showed my garden buddy/neighbour and preached about them. The next day he said that they create a bunch of radiation, and the electro magnetic field they give off is bad for you? I could grow all year with these and get a mega head start for spring. I also don't want to expose myself to radiation at high levels or electro magnetic wubb-wubbs. How bad are these? I'm think in five years I could have as many as six? Thanks! | [
"It's safe. The most you have to worry about is interference for your radios, which shouldn't happen with newer lamps. ",
"The radiation they emit is radio waves. It's perfectly safe. "
] | [
"http://imgur.com/dNqrjlS",
"electromagnetic radiation is just a fancy word for light.",
"the kind of radiation that gives you cancer is the high energy sort. short wavelength, high frequency, high enough energy to knock off parts of your DNA and other dangerous stuff.",
"microwaves are lower energy than vis... | [
"Awesome! Thank you!"
] |
[
"Why do individual particles have different concentration gradients?"
] | [
false
] | I'm learning about diffusion in HS biology, and my teacher said that due to the random kinetic energy of particles they will go down their concentration gradient to areas of lower concentration. This makes sense to me. He then went on to say that concentration gradients are individual to different particles, and Co2 and O2 will go down their individual concentration gradients rather than higher concentration of solutes in general would flow towards an area(s) of lower total solute concentration. Why is this? Thanks! | [
"Diffusion of molecular fluids is caused by Brownian motion, i.e. the nearly random motion that results from multiple collisions between particles at atomic scales. It is a process 'powered' by entropy. Diffusion does not happen because the different molecules strongly repel each other. As such, the density individ... | [
"So my understanding of what you said is that because molecules don't \"push off of each-other\" as my teacher put it (which led me to believe that more molecules to push off of led to diffusion away from that area), the only reason they diffuse is their random motion, which I see would randomly distribute particle... | [
"Yes this is true. The particles do collide and scatter at atomic scales and several collisions result into a motion for each particle that appears random. Given that the molecules will not react with each other, they do not feel their density over large scales. The large-scale distribution in space and its dynamic... |
[
"What would be the best method for us to use if we wanted to send and receive information across vast interstellar distances?"
] | [
false
] | Is it possible to create, say, a radio wave laser? How far could such a laser reach though space? I've heard that even lasers do spread out a bit. Would a radio wave laser be our best option for interstellar communication, or would it be better to transmit with something like the I heard from that it would be possible for the Arecibo Observatory to communicate with another similar-sized dish located half the distance to our galactic center. That's pretty far. Is that really true? (Of course, it would take a very long time.) How focused of a beam can this thing make? Would a laser reach farther? | [
"Remember what subreddit you are in! That is science fiction. Besides, if I wanted a solution from science fiction, I'd have gone with the ",
"ansible."
] | [
"Remember what subreddit you are in! That is science fiction. Besides, if I wanted a solution from science fiction, I'd have gone with the ",
"ansible."
] | [
"I don't know about the 'maser' wonderfuldog mentioned, so it's worth looking into that. I also don't know about this talk on Cosmos about the Arecibo Observatory. Last time I checked, there really wasn't any feasible way to transmit data over interstellar distances - the power required to overcome the inverse-squa... |
[
"Are there more \"demons\" in physics than Maxwell's and Laplace's?"
] | [
false
] | null | [
"I'm not aware of any other \"demons\" in physics, so in the following I'll sway away from your question a bit to at least try to get a list started of things in the same ballpark. There is ",
"Descartes' Demon",
", ",
"Morton's Demon",
", the ",
"Utility Monster",
", ",
"Newcomb's Predictor",
", ",... | [
"In this respect, merely knowing about the Basilisk — e.g., reading this article — opens you up to hypothetical punishment from the hypothetical superintelligence.",
"Geez thanks."
] | [
"It's a thought experiment to see if the second law of thermodynamics could actually be violated. It's purpose wasn't to find a mechanism that changes the temperature of two chambers."
] |
[
"If we had bred domesticated cats the way we did dogs would we have large house cats (size of great danes) and mini cats (size of chihuahua)"
] | [
false
] | From what I understand cats were never selectively bred in the same way dogs were. | [
"Yes, dog breeding is not that ancient and the changes we see today have been achieved in a shot time span.They do it with cows and other animals we use, it would work with cats too."
] | [
"there is a large house cat you can get called a shavana cat i think it costs £12,000 its a normal cat crossed with a african wild cat bout the size f a medium dog an plays fetch."
] | [
"We would definitely have a wider range of cats if we focused more on selective breeding. ",
"However, I remember hearing somewhere (believe it was a Ngeog in the womb show) that dogs have a particular gene(or just disposition) to huge rapid changes in their physiology making them the perfect candidate for accele... |
[
"Was the \"seasonal flu\" a phenomenon before the 1918 Flu Pandemic?"
] | [
false
] | I was reading that casually dropped this paragraph: If we are lucky, year over year, SARS-CoV-2 will evolve to cause milder disease than it has these past two years. That would be consistent with the virus that spread in 1918, which became the seasonal flu. It never again produced the same level of mortality as it did during its first two years, but the virus continues to evolve and kill hundreds of thousands of people every year. Most of us have come to accept this as inevitable. Were seasonal flus not a thing prior to 1918? Did urban dwellers and other people in 1910, 1850, 1600 not head into winter half-expecting to catch the flu? | [
"The 1918 flu was the origin of one strain of seasonal flu, but others are older. The word \"influenza\" itself comes from an Italian phrase \"influenza di freddo\" which bascially means \"influence of cold\" which goes back to the 1300's. As the name indicates, it was associated with cold weather even then. It ... | [
"You're misreading that section as saying that seasonal flu didn't exist before 1918. What it's actually saying is that the 1918 flu became the seasonal flu, by ",
" the seasonal influenza virus(es) that were circulating at the time. All the seasonal influenzas we are now (2021) infected with are direct descendan... | [
"Flu was a thing before 1918, but in 1918 there was a new strain of H1N1 which most people had no immunity to (was zoonotic and had just crossed from birds to humans). If I remember correctly some old people did as they was a similar virus like 30 years earlier. Hence part of the reason the death rate was lower in ... |
[
"Is there any validity to the claim that humans are capable of absorbing adrenaline from animal meat?"
] | [
false
] | null | [
"Firstly animals are undoubtedly stressed when they are slaughtered or during the build up and as such will release hormones such as adrenaline into their bloodstream. Secondly the idea that it would disrupt our own adrenaline balance is because adrenaline does not have a negative feedback mechanism and so the addi... | [
"Correct, adrenaline is the molecule ",
" 9 ",
" 13 ",
" 3 . It has a few different molecular configurations, but all are treated by the body identically, and the molecule is the same in all animals that possess it."
] | [
"Dumb question, ",
"Adrenaline is adrenaline right? I mean it's just a molecule, there isn't a difference between human and animal adrenaline?"
] |
[
"Why is having an extra chromosome bad?"
] | [
false
] | Why does having an extra chromosome lead to Down's syndrome and not provide additional genetic instructions that are beneficial or at least benign? | [
"There actually are some benefits to having an extra chromosome. For example, individuals with Down's Syndrome have a much lower risk of many types of cancer:",
"http://www.nature.com/nature/journal/v459/n7250/abs/nature08062.html",
"Obviously the benefits are vastly outweighed by the other problems suffered b... | [
"I think the exact mechanism of this is largely still a mystery but a group of researchers have found that an extra chromosome has an impact on the localisation of DNA within the cell which leads to changes in the normal gene expression profile and messes up the equilibrium.",
"Here's",
" the reference to the s... | [
"As you know, Down's Syndrome is caused by an extra copy of chromosome 21 in humans (three copies, rather than the usual two).",
"Down's Syndrome phenotypes (characteristics) have long been thought to be caused by gene overdosage - i.e. the 50% increase in expression at the RNA level of trisomic genes [",
"Niko... |
[
"Why is time a physical aspect of the universe, instead of only space?"
] | [
false
] | null | [
"It has to do with the fact that the gravitational field has to be \"divergence free\" in empty space. What this means is that in the spaces between matter, the field has to \"spread out\" in such a way that there are no sources or sinks of gravity. The number of dimensions there are in space determine exactly how ... | [
"There isn't really a why. It's just something we observe about the universe. Asking that is similar to asking why we can move in 3 directions spatially instead of 2, 4 or any other number."
] | [
"If there existed a 4th dimension, what would it look like?"
] |
[
"If the human body's response to infection is a fever because heat kills the pathogens, Aren't we delaying the healing process with fever reducing drugs?"
] | [
false
] | null | [
"As a general rule in health care, we don't give fever reducing medications unless a fever is above 101.5 just for that reason. The heat does indeed kill the pathogens, but on the flip side, we must closely monitor to make sure the fever does not become high enough to cause damage to the body in the process. ",
... | [
"Fevers do indeed kill the pathogens (somewhat) but fevers also serve the purpose of speeding up the chemical/metabolic processes in your body that are killing the pathogen and helping you heal. ",
"We run into trouble when the fever starts getting so high that these processes are actually negatively affected, ... | [
"This is for the most part true, but I would like to expand upon your statement.",
"In actuality, fevers are likely mismanaged in most hospital settings. Though I am sure that there are exceptions, fevers will not cause bodily harm until a temp of 107.6 Fahrenheit is reached (at which point brain damage may resul... |
[
"In places on the earth where the sun never rises at some times of the year, do plants that live there die as they cannot perform photosynthesis?"
] | [
false
] | null | [
"All plants dont always need photosynthesis to live. All plants can consume oxygen the same way humans and animals do. The same way plants dont die during the night :)",
"But to answer your question -> no plants dont die, we do have less plant life in general and fewer divers species of plants because of this"
] | [
"Also, the places you mention have no sun in the winter, and there are a lot of places where plants go dormant in the winter, so the lack of sunshine isn't as critical as you might think."
] | [
"I live where that are many maples and conifers.\nMost plants here just go into hibernation when the sun does not shine for a few weeks and temp is like -40C\nBut as soon as spring hits! They are growing WIIILD",
"Plant hibernation works a lot like animal hibernation. They consume water and oxygen stored in the r... |
[
"Is there any actual evidence that genetically modified crops are harmful to people or the environment?"
] | [
false
] | I occasionally peruse , and the vast majority of people make some pretty serious allegations about the affects of GM crops on human and environmental health. Are there any actual concerns about the current state of affairs or is it another case of the general public fearing something it doesn't understand? | [
"GM crops in general are totally and completely harmless. It's pretty much impossible for plant DNA to be harmful to humans in any way - you eat DNA in every single item of food ever made, and it doesn't have any significant effects on you.",
"It is possible to create a GM organism that is harmful. For obvious re... | [
"That's a consumer rights issue, not a GMO issue, though."
] | [
"One of my biggest objections to GM monoculture is that some seed companies are using GM to create sterile seedlings so a farmer is not only legally banned but technically banned from saving aside seeds and replanting them the following years. That just seems \"wrong\" to me that we're setting our world's food sec... |
[
"Roughly how long will it be before a manned ship could catch up with, and retrieve, Voyager 1?"
] | [
false
] | That little guy is 11 billion miles from Earth at the moment. Astronomers like to think of distances in terms of 'light-years.' Well, we're not anything like a 'light-year,' but we're now a substantial fraction of a 'light-day' from the Earth," says Gurnett. "And I just find that extremely impressive. So, with the current (or predicted) rate of technological advancement, when is it feasible we could catch up with it? I'd like to think that we would so that it could be housed in a museum..but I guess we wouldn't head in that direction unless it were part of a longer trip. | [
"Voyager 1's current velocity is only ~3.5AU/yr. The JHUAPL has been working closely with NASA on the ",
"Innovative Interstellar Explorer",
" project, which is a Voyager-style mission with a target velocity of ~13AU/yr. They're looking at several different propulsion schemes, but seem to be focusing on ion pro... | [
"Show me the blueprints for your designed ship that can carry enough fuel to constantly accelerate at 1 g for 1 year solid. And then explain how you are going to get it into orbit. And then explain how you are going to fuel it up."
] | [
"Yes, unfortunately.",
"People like to dream of faster than light travel, or even near light travel. but in reality no real physics can even theorize how it could be achieved, at least on the scale of craft that could carry humans and the timescale of a human life.",
"Who knows what we may discover to alter th... |
[
"Do insects sleep? If so, how?"
] | [
false
] | null | [
"The answer first requires that we define \"sleep\".",
"In mammals, we tend to define sleep based on the following criteria:",
"A state of reduced activity and often changed posture",
"A state of reduced responsiveness to environmental stimuli, with the ability to rapidly return to wake if a strong enough sti... | [
"Wow thank you! Very informative!"
] | [
"Is it possible that sleep/inactivity is the normal state of being and only certain organisms developed/evolved an activity period depending on different stimulus(mostly light) , a period we call being awake ; since what would be called normal was inactivity/rest , the organism must return to that state from time t... |
[
"Is a barrel of compressed air more buoyant on water than a normal barrel of air?"
] | [
false
] | [deleted] | [
"And thus, the less buoyant."
] | [
"The amount of air in a contained volume will matter since density is reliant on the mass per volume. The more compressed air is, the more molecular weight it has, the more dense it is in a contained volume. I hope this helped."
] | [
"No it is less buoyant. Buoyancy is all about difference in density. The less difference the less buoyancy per unit of volume."
] |
[
"What is denser: A black hole or a neutrons star?"
] | [
false
] | Thank you. | [
" It depends what you mean by the 'density of the black hole.'",
" Neutron stars are generally taken to be the densest form of matter, since black holes are more of a feature of spacetime than a kind of matter with any typical thermodynamic descriptors (pressure, density, etc).",
"The cores of neutron stars rea... | [
"Quick, concise, and easy to understand. Thank you for your knowledge. :) Opened this thread assuming it was without question a black hole, not realizing there was that much nuance."
] | [
"Thank you very much for your explanation."
] |
[
"Is the reason you can't see stars in the moon pictures because the sun is shining or the camera quality (or both)?"
] | [
false
] | [deleted] | [
"Camera quality may be part of it, but the main reason you can't see stars in moon pictures is because the moon pictures were pretty much all taken during daytime on the moon, so the lunar surface (and the astronauts and flags and golf clubs and whatnot) were all extremely brightly illuminated. Think noon at the eq... | [
"When you take a picture on default settings your exposure time is quite small. Exposure time is how long the camera is taking light for. Stars are very faint and need a long exposure time to be taken in a photo. For the moon you do not need a long exposure because it is bright, but to get some features of the moon... | [
"Ah okay that's what I was wondering :)",
"Had been staring at a framed time magazine on my wall from the moon landings and was thinking about if the atmosphere made that much of a difference in star visibility or if it was simply the sun+reflected light.",
"So I'm guessing the darkside of the moon would have q... |
[
"Name of a bird Help"
] | [
false
] | null | [
"I think the folks over at ",
"r/ornithology",
" will be able to help a lot more. Thanks for your interest in AskScience!"
] | [
"Thanks for the help. Sorry for asking in the wrong channel."
] | [
"no problem whatsoever. Please feel free to ask any other scientific questions you may have in this forum. "
] |
[
"Could enough mosquitos kill you?"
] | [
false
] | null | [
"One, could be less than 2 weeks if it was carrying ",
" or yellow fever virus.",
"From the blood loss alone... more difficult. Estimating 3 uL per mosquito and 4.7 L of blood it would take 1.57 million mosquitoes to drain your blood. Average human BSA is 20,000 cm",
" estimating 1 cm",
" per mosquito gives... | [
"To pick up on a technicality, blood loss can be fatal after losing upwards of 40% of total volume. Using your calculations, this will translate as 1.88 L of blood loss from approximately 627,000 mosquitoes."
] | [
"Also the time is probably an underestimate as skin perfusion would decline as they went into shock and they would probably be lying down, reducing available surface area. "
] |
[
"How can someone get a new theory evaluated?"
] | [
false
] | null | [
"This might be more suited for ",
"/r/academia",
", but anyway:",
"The main thing to do to get a theory out there is to publish a paper in a scientific journal. There's a wide spectrum of journals and especially in broad fields. Journals range from very broad (Science, Nature) to extremely specific to a certa... | [
"Publishing in peer-reviewed physics journals would be a good start."
] | [
"Others have mentioned publishing the theory in a peer-reviewed journal, but this is basically an insurmountable obstacle for someone outside the field (unless the journal is of particularly poor quality, in which case publishing there won't accomplish anything anyway).",
"I'm going to work under the assumption t... |
[
"How can vegetables be grown at accelerated rates in indoor farms?"
] | [
false
] | How can they make it grown two times faster, and why are this farms not widely used? I know the precise wavelength of light is involved, but do nutrients and light schedules are taken into consideration or is it something special behind this accelerated growth. | [
"Basically you can 'optimize' conditions for plant growth i.e. provide the exact amount of water, the correct balance of nutrients, soil or hydroponic conditions and length/ intensity of (sun)light. ",
"Under natural conditions these are going to be over or under provided thus reducing plant growth efficiency. If... | [
"Is there a table where I can check all of this for different vegetables? ",
"I can dig around in some journals and let you know. Off the top of my head no. There are loads of books out there that give great advice. You can pick them up for about £20/22-24$. I will PM you some names.",
"When it comes to tempera... | [
"Thank you! is there a table where I can check all of this for different vegetables? when it comes to temperature is it more important the soil temperature or the air temperature?"
] |
[
"What happened to the Global Cooling scare of the 1980's?"
] | [
false
] | Not that I don't believe in global warming or anything, but im just generally curious | [
"There wasn't a Global Cooling scare in the 1980s. The people who claim there was are lying in order to sell their bigger lie that there's doubt about global warming.",
"Where does the myth come from? Naturally enough, there is a kernel of truth behind it all. Firstly, there was a trend of cooling from the 40’s t... | [
"Here is ",
"a graph showing the frequency of \"global warming\" and \"global cooling\"",
" in books from 1970 to 2008, based on data from the ",
"Google Ngram service",
". It shows that \"global warming\" was mentioned 3 to 50 times more often than \"global cooling\" in the 1980s. In the 70s they were pret... | [
"I distinctly recall hearing about a possible coming ice age when I was in elementary school in the mid 70's. Could have been on \"In Search of...\" I grew up going to the La Brea Tar Pits and was fascinated by the remains of pleistocene animals, so talk of another ice age stood out."
] |
[
"How small can a star be?"
] | [
false
] | Eventually: how small is the smallest known star? | [
"Stars start to fuse hydrogen at about 80 times the mass of Jupiter. Below this, they are brown dwarves. Above about 12 times the mass of Jupiter they also fuse deuterium, and this is a grey area as to whether you want to call these stars or not."
] | [
"If by \"small\" you mean radius, neutron stars can be as small as 12km in radius, approximately the size of a large city. However, these stars are still very massive and therefore incredibly dense. A common way of expressing this is that one teaspoon of a neutron star would weigh a few billion tons."
] | [
"The smallest hydrogen burning stars are red dwarfs with about 80 Jupiter masses, with a diameter only slightly larger than Jupiter (they are much more dense). Dead stars, like white dwarfs and neutron stars, are much smaller, but much more massive than a red dwarf."
] |
[
"Why is it that sometimes if you get a cut it won't hurt until you notice the wound?"
] | [
false
] | Example: today I was spraying something with a hose and I guess the metal cut my hand. I didn't feel it at all until I noticed the blood trickle onto the hose and my hand was covered in blood. It was a pretty decent sized cut too. Only when I looked at it is when it started to sting. Isn't pain supposed to let you know when you've hurt yourself? Why didn't it hurt when it happened and only after I looked at it? Edit: , neuroscience, . Edit 3: Thank you all for answering my question! To those who were wondering, no the wound wasn't that deep and it's healing fine. Also, I was not asking for medical advice, just wondering about the experience of delayed pain. | [
"If you were applying pressure to the area of the wound (holding the hose?) then ",
"lateral inhibition",
" is likely your culprit here. Your nerves were detecting pressure to the wound and that was minimizing the pain feeling."
] | [
"I would say from a psychology standpoint, you were probably putting a lot of your attention into whatever you were doing and your brain decided it really wasn't that important to be brought to your conscious attention so you were unconsciously dealing with it. Then as you became consciously aware of it by seeing i... | [
"I can't speak to tactile sensation, but attentional effects would explain this type of effect for other sensory modalities. It's a phenomenon known as ",
"selective attention",
" and it can cause you not to notice a lot of different things. "
] |
[
"Is there any evidence of two seperate planets orbiting an object in the same path but not colliding?"
] | [
false
] | null | [
"The simplest way for this to happen is for a smaller object to be a Trojan at a Lagrange point of a larger object. ",
"The Trojan asteroids around Jupiter",
" are an example. Saturn also has Trojan moons: Callysto and Telesto are co-orbital with the larger moon Tethys."
] | [
"Epimetheus & Janus - moons of Saturn",
"https://en.wikipedia.org/wiki/Epimetheus_(moon)",
"https://en.wikipedia.org/wiki/Janus_(moon)",
"Explanation with animation - ",
"http://www.ac-ilsestante.it/en/ASTRONOMIA/i_grandi_astronomi/Newton/animazioni_newton/janusepime/janusepime_newton/janusepime_newton_01_b... | [
"Although strictly speaking the smaller one would be a moon. And it does have to be significantly smaller. If you tried it with a double planet, it would be unstable. Like when ",
"Theia",
" got too big and collided with Earth. Or the rest of Earth, given that Theia makes up a significant portion of what we now... |
[
"Why is the speed of light the universal speed limit?"
] | [
false
] | Title says it all | [
"A postulate is something that you just start off with. You say \"Let's suppose that ",
" is true. Then what?\" And it turned out that supposing light travels at the speed of light (relative to ",
" observer), meant that everything just ",
", and he managed to develop a testable theory (that of Special Relati... | [
"I could give you a lot of different answers or explanations, but it would all be circular. The reason is this- it's taken as a postulate, or assumption, in the theory of relativity. It's a very good assumption that agrees with every measurement ever made, but it's an axiom of the theory, which we take to be true f... | [
"This question really cannot be answered with anything but \"because that''s the way the universe seems to work.\" ",
"I know this seems unsatisfying, but at some point, we have to accept that this is just a fact we experimentally discovered and built a theory on. ",
"If you are interested in the math, check o... |
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