title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"[Biology] [Computer Science] Can we make animal simulations?"
] | [
false
] | null | [
"We can't simulate things with that detail. We can simulate gross behavior or learning or \"evolution\" to a certain extent, but not at the level you describe."
] | [
"Is there a reason why? Should this eventually be possible? What are the current limitations preventing it from being done?"
] | [
"We can't simulate at the atomic level because there are too many atoms. We don't know how they are organized relative to each other. We don't know what kinds of processes and structures exist at higher levels. We are discovering new proteins and celular mechanisms all the time. We can only approximate very coarsly... |
[
"Why is the sky in the evening red/orange colored but not in the morning?"
] | [
false
] | A simple question i couldnt find an answer on myself. I was thinking alot about it and was quite surprised i dont know why its reddish in the evening and quite blueish in the morning. | [
"Because evening sky contains more particles of dust, water, clouds etc. Wikipedia ",
"mentions that",
" and gives a bunch of citations.",
"Note that from what I can tell there are ",
" effects at play, very small particles and water vapor increase Rayleigh scattering which makes sunlight redder, while larg... | [
"Hm, i never thought about it being only psychological. Makes sense to be honest :) Thanks for the answer"
] | [
"Hm, i never thought about it being only psychological. Makes sense to be honest :) Thanks for the answer"
] |
[
"AskScience AMA Series: I am Tracee Gilbert, a systems engineer who started a company that provides engineering and management services to the Office of the Secretary of Defense. Ask Me Anything!"
] | [
false
] | Dr. Tracee Walker Gilbert is a passionate entrepreneur and systems engineering executive. Dr. Gilbert owns and operates System Innovation, LLC, which provides systems engineering and program management services to various clients in the Office of the Secretary of Defense (OSD). She has over 17 years of experience leadi... | [
"Can you please define Systems Engineering so that a layman can understand it?"
] | [
"Do you have any ethical limits around what you develop and how it might be used?"
] | [
"Working as an engineer, ethical discussions are typically not a part of the day to day work responsibilities of designing, developing, and delivering technical systems. ",
"I find your answer troubling. Many years ago I myself chose to end my employment with a major engineering consultancy rather than get involv... |
[
"When physicists talk about particle entanglement, how exactly are they identifying the second particle to which the first particle is entangled with?"
] | [
false
] | null | [
"First, entanglement is not some pre-existing condition for all particles. Given a particle A there is no way to identify any particle B that is entangled to it. In fact, given a single pair of particles there is no way to find out if they are entangled at all!",
"Entanglement is a property of the system. If I ha... | [
"1) Entanglement is as stable as the particle state. Anything that causes decoherence or wave function collapse will destroy the entanglement. In practice the biggest problem is heat, as random particle motions will reduce your coherence length.",
"2) Useful faster than light communication is not possible with en... | [
"Distance doesn't matter, but you cannot use entanglement to transmit information in any way. This is the ",
"no-communication theorem",
"."
] |
[
"Will two analog TV tuners tuned to the same non-broadcasting channel display the same pattern of 'snow'?"
] | [
false
] | Put two identical old CRT televisions next to each other tuned to some non-broadcasting channel.. will they display the exact same static/snow? Obviously I'm not talking about TVs that switch to a blue screen when there's no signal detected. | [
"They would not. The snow you're seeing on the screen is the television's best shot at creating a picture based on the signal it is receiving, which in this case is for all intents and purposes random noise. Even if both were being fed by the same antenna, I would expect that the cabling from the antenna to the t... | [
"I believe you are correct. In that situation, the tuner is receiving a very poor signal-to-noise ratio input, which it will then amplify. Small fluctuations in the circuit's immediate environment (and things like shot noise in the circuit itself) will provide significant amounts of the resulting signal, which wil... | [
"Colour information (chrominance) is heralded by specific signal patterns (NTSC or PAL synch bursts) that help proper colour signal detection. These signals are relatively long and very unlikely to be mimicked by random noise.",
"The receiver shuts down the whole colour detection chain if the synch bursts are not... |
[
"How can radiowaves be identified by their \"wavelength\" when the signal that is received and heard by a radio system clearly isn't periodical and doesn't seem to be connected to any specific wavelength ?"
] | [
false
] | null | [
"I'm a little confused by your question. The signal received by a radio system IS periodic, that's really the only way this all works. Radio receivers have an antenna that is tuned to a specific frequency (or wavelength, which is inversely proportional to frequency), and they're able to do that through periodic osc... | [
"The carrier signal ",
" periodic. The content you hear is modulated onto the carrier signal. ",
"AM Radio",
" is possibly the simplest to look at and understand-- the frequency of the carrier stays the same. The sound is encoded into that carrier wave by changing the amplitude of the signal in time with t... | [
"The question may be about the signal not being ",
" periodic. A radio station can transmit noise and clicks. But as you say, that is encoded by modulation of a carrier wave, and then demodulated in the receiver that is tuned to the wavelength of the carrier."
] |
[
"Why are bullets made of lead?"
] | [
false
] | Also: what are the advantages of depleted uranium bullets? How would iron, steel, golden, silver, patinum, etc, bullets behave? | [
"Lead is widely favored because it occupies a happy balance of two priorities -- density and affordability. The more dense a slug is, the more kinetic energy can be delivered for a given slug size and muzzle velocity. Also, factors like a strong crosswind will be less problematic for more dense slugs. Depleted u... | [
"You want a bullet to have several attributes. First and foremost would be mass density. You want it to be aerodynamic and heavy. Lead is nearly as heavy as gold but is much cheaper. Also, because it is a soft metal, when it impacts something, even flesh it can spread on impact maximising damage and increasing exit... | [
"What other people said, but particularly about softness, you want a bullet to deform slightly as is goes down the barrel in order to catch the rifling grooves that impart spin to the round which makes it fly in a tight spiral like a football. Softer metals also wear the barrel less over the course of its life."
] |
[
"When a leaf falls from a tree does it stop the process of photosynthesis, does the leaf just kind of give up?"
] | [
false
] | null | [
"If the leaf did not fall of because it was dead, but due to mechanical damage to the stem etc. it will continue to function normally until it loses to much hydration and dies. Flowers with leaves in a vase will continue to photosynthesize as well for a while."
] | [
"Yep, this is why you should put picked flowers/plants in water. They can pull the water up the leaves and survive a bit longer."
] | [
"Even better, some cut leaves or stems can grow roots and survive as independent plants when put in damp compost, which is how cuttings are taken to propagate some plants."
] |
[
"How are Quasar emissions different from Hawking Radiation? Is the emission created from blowback from overcrowding arround the accretion disc, or is it un-paired anti-particles generated at the event horizon like with Hawking Radiation?"
] | [
false
] | To put it another way, is the emission spectrum of a Quasar (which I'm reading is electromagnetic energy distributed pretty evenly across the spectrum) the result of too much matter trying to cram into too small a space, and the fricative excitations being spat back out as photons? (and are there other types of particl... | [
"The actual mechanism by which quasars/black holes in general emit high-energy radiation is still somewhat unknown, because it's such an extreme environment and many different types of physics come into play; extremely strong gravity, highly magnetized plasmas, and all sorts of complicated stuff that is very very h... | [
"A quasar is a distant galaxy in which the central supermassive black hole (SMBH) is active (an active galactic nucleus, or AGN), in the sense that it is accreting material, which is emitting radiation that we can see.",
"The ",
"general picture of an AGN",
" is one of a supermassive black hole surrounded by ... | [
"Exactly what I was looking for. Thank you. "
] |
[
"Is there evidence surgical masks being worn by people who are ill significantly help limit infection of others?"
] | [
false
] | I know this is common practice in Asia and, particularly in places with high population density and in tight public quarters it makes sense, but is there evidence this significantly helps reduce infection rates, or is this mostly an old wives’ tale? | [
"\"For many years, scientists weren't sure if wearing a mask was effective at preventing the spread of viruses. However, recent studies suggest that they can help.",
"First, a 2008 study published in the International Journal of Infectious Diseases concluded that when used correctly, masks are highly effective in... | [
"No. I don't blame you for that. Even at the end of the article I quoted they cite the results as being inconclusive. Even I have a hard time believing surgical masks can stop anything. Maybe if you're coughing and spitting up fluids, but they can't possibly stop airborne viruses."
] | [
"Sorry mate, just reread your post and saw that plain as day. My sincere apologies. I agree with your point on them helping against folk spitting things up etc but I imagine it's also the people more likely to wear the masks are also more likely to be more hygienic in general (washing hands etc)"
] |
[
"How does one contain anti-matter?"
] | [
false
] | [deleted] | [
"Antimatter responds to electromagnetic fields in the same way as ordinary matter - albeit in the opposite direction, so assuming the antimatter is charged then it can be levitated and trapped with such fields. If it's not charged, (such as an anti-hydrogen atom) you might contain it using an ",
"optical trap",
... | [
"CERN is doing just that. Read about their experiments with trapped antihydrogen:",
"ALPHA",
"ATRAP"
] | [
"I'd suggest reading the Wikipedia article on ",
"Penning Traps",
" in addition to the other links you've been recommended."
] |
[
"Black hole radiation as an energy source"
] | [
false
] | Something I have thought about for a while. Given that: - Every black whole evaporates in time x, where x is proportional (I guess exponentially?) to it's Schwarzschild radius - No matter/energy may "disappear", thus the entire mass of a blackhole will have evaporated by time x .. could black holes not be the ultimate... | [
"Neat idea.",
"A few things to keep in mind:",
"A black hole that weighed 10000 tons would be 0.01% the size of a proton.",
"You'd have to keep it still so you could feed/extract energy. It's very hard to keep something that heavy stable, so I think the only solution would be to have it in orbit.",
"Things ... | [
"There are purportedly primeval black holes around, which are about to evaporate. I think one would settle for a more practical evaporation rate, as 1 g/s. The radiation could be attenuated by its accretion disk.",
"http://en.wikipedia.org/wiki/Micro_black_hole"
] | [
"It's named Hawking Radiation, named after Stephen Hawkings.",
"It is based on quantum flactuation right at the Event Horizon, requiring a tiny amount of energy (and thus mass) to escape.",
"I quote Wiki:\n\"Close to the event horizon of a black hole, a local observer must accelerate to keep from falling in. An... |
[
"Why is Helium-4 called an isotope if it has 2 protons, 2 neutrons, and 2 electrons just like Helium which is not an isotope?"
] | [
false
] | null | [
"Helium has 2, protons, 2 neutrons, and 2 electrons",
"That's just helium-4, not all helium."
] | [
"Oh would you look at that, its you again! Anyways, what do you mean exactly? So that is the atom of helium-4 but not helium?"
] | [
"That statement is true of helium-4, but not of helium-3, or any other isotope of helium.",
"Helium-4 has two neutrons, helium-3 only has one neutron. In general, helium has nine isotopes which have been studied experimentally. But only helium-3 and helium-4 are stable."
] |
[
"At what point does compressed coal become non- combustible?"
] | [
false
] | [deleted] | [
"To be absolutely clear about this - coal does not form diamonds.",
"Diamond is crystalline carbon - a mineral. Coal is a rock, composed ",
" but not exclusively of carbon. Rather than being a solid carbon lattice, coal is an amalgam of many many various hydrocarbon chemicals ",
"such as this",
". ",
"D... | [
"Diamond is the structure achieved when each carbon atom forms 4 separate covalent (sigma) bonds with other carbon atoms, which forms a kind of network of linked carbon atoms. This is very strong. Coal does not have this chemical structure (although after google-ing it I still couldn't determine the bonding of coal... | [
"What material do they use to manufacture diamonds for things like drillbits?"
] |
[
"Is it possible to have genetically identical children that aren't twins?"
] | [
false
] | If half of a person's genes come from the mother and half from the father, couldn't the exact same genes be randomly selected the second time a couple conceives, resulting in a genetically identical child as the first? | [
"It's theoretically possible, but not exactly feasible.",
"The human genome is composed of 23 pairs chromosomes (each pair contains one copy of the chromosome from your mother, and one copy from your father). Each gamete (sperm or egg) gets a random selection from each pair. Thus, for one individual (and ignori... | [
"That's even before taking into account crossing over during meiosis creating new recombinants out of each pair of chromosomes before they are segregated into the gametes.",
"From a citation in ",
"this",
" paper: \"...the overall number of detectable recombinational events per meiosis [...] In females, the a... | [
"They could, but also unlikely unless something goes wrong. When crossing over happens, the chromosomes pair up at regions of homology, where the sequence on each one is identical (or close enough to identical). This crossing over could happen anywhere along the chromosome, not necessarily just within genes, and th... |
[
"Are the neurological effects that are being linked to COVID-19 likely to be unique to SARS-CoV-2, or could they be common to many types of coronavirus but have gone undetected because it hasn’t been extensively researched until now?"
] | [
false
] | It seems like the rate of reported neurological effects is pretty low, so is it possible that other coronaviruses could have had the same effects, but the correlation just hadn’t been made yet due to less attention being paid to them? Or is it too early to speculate on that yet? | [
"Neurological complications from COVID-19 are actually extremely common, especially in hospitalized patients. I've seen a range of values, but it's something on the order of 30-60%, depending on various factors. There are many viral and bacterial infections that can result in neurological complications and sequelae... | [
"Thanks for the links!"
] | [
"Most of the neurological complications have been related to sepsis (problems with blood pressure perfusing the brain), strokes (blood clots), or benign loss of smell. Sepsis is common to most infections of the body. The strokes are interesting, were seeing young healthy patients who are hyper-coagulable and have r... |
[
"Why can't mosquitoes transfer STDs?"
] | [
false
] | [deleted] | [
"I imagine you could possibly construct a theoretical scenario where a mosquito could transmit HIV but generally when looking at transmission we are interested in the statistical likelihood, which is very very unlikely (zero cases of infection ever attributed to mosquitoes, AFAIK, and it is not due to lack of mosqu... | [
"Not sure about other STDs, but mosquitoes actually digest HIV along with blood. Since it needs to stay alive to be spread, HIV can't be transferred via mosquito. "
] | [
"right now i cannot find the article about it but I think i have read an article that the scientists found out that the mechanism of mosquitoes. They found out that the mosquitoes do not inject the previous victim's blood into other's blood system. But they inject their saliva which cause people to get mosquito bor... |
[
"Can prion diseases be transmitted via a bite from a wild animal such as a squirrel?"
] | [
false
] | null | [
"There are only a handful of cases I was able to find where a prion disease was transmitted from a squirrel to a human, and they all involved eating the brains from an infected squirrel. In general, prions aren't really known to be transmitted by bite. Rabies would probably be the bigger concern, although it's very... | [
"I mean this with all sincerity and kindness, you have an anxiety problem, not a squirrel bite problem."
] | [
"So I noticed your answer didn't include prions (miss-folded proteins that cause neurological disorders), which OP was asking about. I have been doing some literature research on Chronic Wasting Disease (prion disease) and am finding out transmission via ingestion really depends on the particle load of the ingested... |
[
"How do you make this change of variables?"
] | [
false
] | null | [
"It's called a double integral. Generally, you integrate f(a,b) with respect to b (treating a as constant), and then with respect to a (treating b as constant). It depends on the problem, though, and generally this only works for definite integrals.",
"What's the problem you're doing?"
] | [
"I'm trying to understand a concept in my Statistical Mechanics course. It says that if you have a Gaussian variable x then you can get <exp[iqx]> (where <> denotes the average, q is a real unmber and i is imagiary) by integrating that times the Gaussian distribution. Now if you have another random variable R defin... | [
"This sounds like a homework question, so your post would probably be more appropriate for ",
"/r/learnmath",
", ",
"/r/cheatatmathhomework",
" or ",
"/r/homeworkhelp",
". ",
"However, the integral doesn't really make sense in this context without more information: Why is x the sum of two variables, a... |
[
"Eating fatty food all at once, as opposed to spread out over a period of time."
] | [
false
] | I maintain a pretty strict diet, but once a week I let myself go with about 30 chicken wings. I have a theory that since im eating so much calories at once, my body can't absorb it all and this is better than eating 30 wings spread out over the course of a few days. Is this right? | [
"No not particularly. Your body might not absorb it all as efficiently, but it's going to do a pretty good job. The wings are sitting in your stomach until there's enough room for them to flow into the small intestine. It's not like your body goes \"shit, we can't get to them all! Abort!\" it just shoves them i... | [
"If this works for you and you aren't gaining weight then go for it. In my years of weight/food problems I've done a bit research on the subject of diet and what I found was that nobody has solid answers to this stuff. Your best bet is finding something that works for you and just doing it. Whatever you do don't ob... | [
"If you are experiencing oily, foul-smelling, fat-laden stools known as steatorrhea, then you are indeed probably overloading your body's ability to absorb fat. If not, then it's unlikely that you're actually cheating your body out of any of those calories; it's absorbing essentially all of them.",
"Furthermore, ... |
[
"Why do video game devs tie physics to framerate?"
] | [
false
] | This recent Need for Speed game, Dark Souls and even Skyrim, a game that was developed with PC in mind do this, but why? | [
"Gamedev here -",
"There are two main strategies for simulating time in game engines. ",
"The first is to assume a fixed time step from frame to frame, and attempt to ensure that the game runs at a frame rate that matches that fixed time step. For example, you might say in a game designed to run at 30fps that e... | [
"Mostly because it's the most straight-forward thing to do. Running the physics is done in frames, just like the rendering. Given the positions and velocities of everything in the system, you calculate what the positions and velocities of everything is going to be one time-step into the future.",
"Then, given tha... | [
"Why would you ignore multithreading? It's 2015, even your toaster probably has multiple cores. Even if you don't have multiple cores, your OS can timeslice you. And the golden rule of multithreading is, if one thread can end up running at the same time as another, sooner or later it will happen, usually with mind-... |
[
"Do animals recognize themselves in mirrors? If so, why do they never seem that interested in what they look like?"
] | [
false
] | Please, no conjecture because you think your dog recognizes itself in a mirror. This isn't a "tell me your anecdote" request. I want facts. Thank you. | [
"From ",
"http://en.wikipedia.org/wiki/Mirror_test",
"Animals that have passed the mirror test include:"
] | [
"Many of them are interested in what they look like. Many of them (like dolphins) are particularly interested in seeing their penises in the mirror (as they can't physically see them)",
"Additionally, there are some other animals that respond to their mirror reflections and even use them for grooming. Koko the go... | [
"Water in the ocean is hardly ever smooth enough to form an image. It happens in lakes and ponds sometimes when the water is still and the light is right, true (hence the \"very few\", as opposed to never). Still the angle is always the same (perfectly horizontal) and the image is rather translucent, which separa... |
[
"What are the most commonly accepted theories of consciousness among scientists today?"
] | [
false
] | null | [
"There is no consensus. The two biggest philosophers of consciousness (Daniel Dennett and David Chalmers) have almost opposite views. Dennett believes that consciousness is not real, only an illusion. Chalmers believes that consciousness is everywhere, part of the fabric of the universe (panpsychism).",
"The most... | [
"The most commonly accepted idea is that we don't actually have any concrete evidence of what our consciousness actually is. Closest scientific explanation would be that the human/homo sapien brain and intelligence was the driving force behind our species' evolutionary split from our other common ancestors. Conscio... | [
"There aren't. There are many philosophical views of consciousness, mostly because it eludes data-driven science so much. They range from the idea that consciousness doesn't even exist, to everything being conscious, to consciousness being an emergent property exclusive to humans, to matrix-like theories. Then if y... |
[
"To what degree is modern technology at risk from a massive solar flare?"
] | [
false
] | Don't know much about this, but have run into some buzz around the web. Two key questions: What is the likelihood of a 'massive' solar flare happening? What would be the effect of such an event on modern technological systems? | [
"The activity we've seen recently has been significant, but nothing really out of the ordinary. It's all the kind of stuff we expect to happen over the course of a typical solar cycle.",
"What we really need to worry about is events like 1859 ",
"Carrington Flare",
". Like that article says, if something like... | [
"You mean solar flares like this one a few weeks ago?",
"\n",
"http://www.youtube.com/watch?v=UXzYpfLFFes",
" ",
"If that was aimed direct at earth that could have wrecked huge havoc on the electrical grid & telecommunications. "
] | [
"Yes, that sort of thing."
] |
[
"Would a single candle in an otherwise unlit circus Hall of Mirrors provide the same lighting effect as an equivalent number of real candles (equivalent to the number of reflections) in a normal room?"
] | [
false
] | If so, how is this possible since energy can't be created? | [
"Think of it this way. For every mirror there is an area NOT lit because light headed for that area was redirected by the mirror, at a loss because the mirror is not 100% efficient.",
"That's where the seemingly \"extra\" light comes from."
] | [
"The mirrors would not reflect 100% of the light, however, so the two situations wouldn't produce the same amount of lighting. "
] | [
"I am a theoretical physicist. When i say mirror, i always mean a infinite, 100% reflecting, perfeclty smooth mirror =). The thought that non perfect mirrors are a thing didn't cross my mind till now."
] |
[
"Why does swelling occur in humans when it is so painful and possibly dangerous."
] | [
false
] | As the title says, why does the human body respond with swelling to an injury/infection where the resulted swelling is possibly a bigger danger or more painful than the cause. I am sure everyone has had their fair share of injuries where so much fluid has built up that once the pressure was relieved than the pain and d... | [
"Inflammation is a protective response by your body, and swelling comes with the package. When immune cells like dendritic cells, macrophages, mastocytes, etc., sense either pathogens or cell damage (death, stuff on the outside that should be on the inside), they send out signalling molecules that do a lot of thin... | [
"The body is designed to respond to a certain range of physiologic stressors. Stressors that extend being that range can cause the body to react in such a way that it's counteproductive"
] | [
"Yes, some or much of the pain is from the swelling. But the signalling molecules that cause such swelling make it hurt more, because they make your neurons more sensitive to pain."
] |
[
"If dogs are domesticated wolves, then where did house cats come from, and why are they all (generally) the same size?"
] | [
false
] | Dogs can be bred for size, certain skills, even color. But cats all seem to be very similar sizes and colors, and behave in similar fashion (whereas some dogs are hunters, trackers, runners, fighters, etc.). And dogs have wolf ancestors, which are similar in size, but where are cats descended from? Bobcats? And how did... | [
"Domestic house cats are descended from the ",
"Near Eastern Wildcat",
" in the Middle East.",
"It is believed they were domesticated around 10-12,000 years ago.",
"Cats are not as readily trainable as dogs are so there was less motive to press them into various service roles. Cats were best to have around... | [
"In addition, for the most part, cats domesticated themselves, outside of the will of humans.",
"The cuter, more docile ones were more accepted when they came onto farms and villages. So those with cats with those traits remained fed by the rodents humans attracted, and those without them had to stay in the wild... | [
"Evolutionary biologist here: although your comment is quite vague, it isn't so vague as to be meaningless. Humans likely do much better in social settings than they would have 20,000 years ago, thus humans have evolved to become better exploited by other humans, i.e. they are more domestic. ",
"Just thought I co... |
[
"Why are new harddrives not under vacuum but instead Helium filled?"
] | [
false
] | What is the benifit of using helium? I understand that there's less airgap with helium but wouldn't drawing a vacuum in the drive also achieve the same reduced airgap from the disc to the head? | [
"Having a gas inside the hard drive lets the read/write head float on a cushion of moving air created by the motion of the spinning disk instead of contacting the material. If they were vacuum-sealed, the head would rub on the disk or you'd have to have extremely tight mechanical tolerance. I also kind of expect th... | [
"I believe helium allows for even lower air resistance / friction, so less energy used. "
] | [
"From the top of my head, vacuuming would require higher strength material compared to a sealed helium atmosphere. ",
"Vacuuming allowed for least resistance to the internal atmosphere while spinning a hard drive. Because of the tight tolerances, I'd imagine high density gases in 'air' could cause turbulence and ... |
[
"Why does a GPS reciever display varying coordinates when stationary?"
] | [
false
] | I know most of you probably don't like when students post their problems asking for help, but I've read the notes, the textbook, searched google and even spoken with classmates and cannot figure this question out. If you know quite a bit about GPS systems, it would be greatly appreciated if you would help me out. The q... | [
"Easy, GPS is always inexact to some degree, and there's no reason to think that at any given moment you're exactly where it says you are. A few moments later, it gets the coordinates again, this time a little different, and so on. ",
" know you're not moving but GPS has no way of knowing that.",
"If the coor... | [
"This paper will answer all you need to know, ",
"http://gauss.gge.unb.ca/papers.pdf/gpsworld.may99.pdf",
". Also you can increase the GPS precision down to orders of ~5cm with the use of known fixed GPS points(ground control points) and differential GPS positioning algorithms. They used differential GPS positi... | [
"GPS actually has two solutions to your position",
"if the receiver is only working from 3 satellites- most modern gps receivers will pull in quite a few more, to increase precision, and reduce lag."
] |
[
"What is this unknown nugget?"
] | [
false
] | I've got a nugget here my girlfriend has had for years, I can't tell what it is. It's quite weighty for it's size. Anyone have any ideas on what it is? Album below: | [
"It looks like Pyrite to me. Here are some techniques people use to differentiate between Pyrite and Gold. Perhaps you could use them to try and confirm whether or not it is Pyrite.",
"Pyrite?",
"Note: Geology isnt my field, so this isnt a highly informed opinion."
] | [
"A bit hard to tell from the picture, since it looks more silvery than it usually would (though that's probably due to lighting), but I'd agree with the others that it's probably pyrite. "
] | [
"I think it's chalcopyrite specifically. My dad and I rock-hounded (gem+mineral collecting from quarries and such) for quite a while when I was a tot, and that was my first instinct on the matter. ",
"In my experience, the smaller, clustery formations tended to be chalcopyrite.",
"Here's a picture of some chalc... |
[
"Regardless of nurture, are some people naturally more likely to go against the norm, while others are the opposite?"
] | [
false
] | My question is mainly about, for instance, people wanting to experiment with drugs, or the people who want to do things just because they're not supposed to, as opposed to others who have never been tempted by drugs, and always followed the straight and narrow. Is this something in our brains that were born with? Or is... | [
"Impulse control plays a huge part. I think many people are curious, but some are far more impulsive. Children raised in the same home can have dramatically different levels of impulsivity, which suggests it's more nature than nurture.",
"Now, I happen to believe impulsivity is not an excuse for carelessness. ... | [
"I never really thought about it in the context of impulse, which makes a lot of sense. ",
"But what about people who fully understand risk assessment and do think about things before doing them, but still make these kinds of decisions?"
] | [
"I never really thought about it in the context of impulse, which makes a lot of sense. ",
"But what about people who fully understand risk assessment and do think about things before doing them, but still make these kinds of decisions?"
] |
[
"Effect of velocity on time dilation"
] | [
false
] | I've heard numerous times that as you approach the speed of light, time will dilate for the observer making 1 year for you, seem like 1,000 for the observer, or something similar. My question is, as you approach the speed of light, does the rate at which time dilates remain the same? As you change accelerate from 10 m/... | [
"I can see that it grows exponentially",
"Be careful with the word \"exponentially\" - technically it means \"like an exponential\" - i.e. exp(x) - which is not how this behaves."
] | [
"The relationship is 1/sqrt(1-v",
" /c",
" ), which increases as v approaches c. Play with different values and see what you find."
] | [
"Oh, well why didn't you say so! This is so much simpler than you might have been led to believe, if you're already fluent in maths.",
"The proper Lorentz group is a symmetry group, SO(1,3), over ℝ",
" in which group operations represent coordinate transforms between different inertial frames.",
"Within that ... |
[
"'ve noticed that some happy couples seem to have unmistakable similarities in physical appearance. Is there any science behind this?"
] | [
false
] | [deleted] | [
"Although not a complete answer to your question, ",
"the matching hypothesis",
" from social psychology does begin to answer your question. The idea is that individuals form relationships (in this case, romantic) with individuals who are approximately equally attractive as they are. There is also research from... | [
"yes, it is a common occurance that alot of people have some similar physical traits to their partners. and basically psychologists more or less attribute it to people being narcissistic. its also possible that it is also is a matter of survival instincts. people are more able to sympathize/feel a connection to thi... | [
"Like likes like, its part of the science of attraction, here is some good reading for you",
"http://en.wikipedia.org/wiki/The_Third_Chimpanzee"
] |
[
"Why doesn't our body heal as fast as our mouth?"
] | [
false
] | [deleted] | [
"Also where there is a lot of blood supply, healing occurs faster compared to less blood supply area. Mouth has good blood supply where some other parts of body does not have. Esp. Cartilage has very little blood supply, so heals a lot slower."
] | [
"You could actually be asking two different things here:",
"1) What are the differences between oral tissue and tissues elsewhere that make our mouths seemingly regenerate so much faster?",
"or",
"2) What is the overarching reason we don't heal faster when clearly some tissues (like our mouths) indicate that ... | [
"Note that fast regeneration time may actually be detrimental. For example, psoriasis is a disease that is based on exceedingly large inflammatory TH1 and TH17 response in reaction to lesions of the skin (and other influences), leading to the expression of several cytokines in the epidermis that stimulate hyperprol... |
[
"Is it true that the human stomach would digest itself if not for the mucus layer?"
] | [
true
] | [deleted] | [
"Yes, which is why people get ulcers."
] | [
"... an ulcer."
] | [
"The digestive fluid contains Hydrochloric Acid. I'll leave it to you to imagine what Hydrochloric acid would do to an unprotected stomach lining."
] |
[
"Is there any correlation between body fat and hair?"
] | [
false
] | I'm not proud to say I gained some weight over the winter (working on getting rid of it) but I noticed that in the areas where I've most gained weight (re: thighs) I seem to be hairier than I remember. I don't know if this is some sort of weird confirmation bias where I suddenly gained fatty thighs and realized I had h... | [
"How about a correlation between body hair and head hair?",
"I've noticed, more than once, that people who have lost the hair on their heads younger tend to also be much hairier. A friend of mine is about 26 or 27, nearly completely bald, but one of the hairiest people I've ever seen w/o a shirt on. I only the ... | [
"Considering that insulin acts as a growth hormone (hence the increase in fat-storing cells in your thighs) there's a chance that the localized increase in insulin may also cause an increase in hair growth/length rate."
] | [
"I imagine that maybe because an area of your body becomes enlarged the hair residing in that area gets more space out. Hence, there is an optical illusion of sorts because it looks like you have a larger area in which there is hair. Imagine you have a square inch of skin, the square has 100 hairs. Then, when you e... |
[
"What would happen to a cadaver left in space?"
] | [
false
] | Would a body decompose, freeze, mummify, or remain essentially "fresh"? Not sure what triggered this question, but I've never heard this question answered. | [
"pressure differential would not cause any significant deformationo of the body, the human body is surprisingly good at holding together under negative pressure. Should the body be perforated in any way however expect the corpse to depressurise, liquids would boil and escape and would leave behind only freezedried ... | [
"In theory, and under extremely precise conditions yes, if a body turned up in a solar system in the stage of forming planets. The body would be among the most gravitational objects in the protoplanetary disc and material would therefore collect around it, increasing the local gravity in that area, drawing more mat... | [
"Here's a really stupid question.. could a cadaver later be turned into a planet somehow? Don't judge me for my stupidity."
] |
[
"Is there any \"cost\" to the body to produce antibodies?"
] | [
false
] | [deleted] | [
"why doesn't the body just have these antibodies in the blood stream at all times,",
"Anti-bodies are tailor made to each disease or type of disease based on it's characteristics."
] | [
"To add onto that: the body can't make an antibody for a specific foreign body if it hasn't \"seen\" it yet."
] | [
"Sort of like the vaccine for smallpox, it is a virus that is related to smallpox. The body makes antibodies to fight this virus which also fights smallpox."
] |
[
"If New York City and Madrid are at about the same latitude why is Madrid so much warmer than New York City?"
] | [
false
] | They're both at about 40 North. Does it have to do with amount of sunlight or humidity? What accounts for the difference in temperatures? | [
"The Gulf Stream brings warmth to Europe, dragging the heat of the equator north to Western Europe. ",
"Edit:",
"Should add that New York has greater extremes in temp.. the cold is colder and the hot can be hotter. This is a product of the continental landmass to the west. The prevailing winds run from west to ... | [
"The Gulf Stream brings warmth to Europe, dragging the heat of the equator north to Western Europe.",
"This is overly simplistic and wrong in the details. First, the Gulf Stream does not extend to Europe - halfway across the basin it loses much of its strength and bifurcates into the North Atlantic Current and A... | [
"If the stream just stopped and attenuated away why would every current map produced since the age of sailing ships indicate the bulk of the water pushing to the European continent. Later maps determined that the current dives deep and runs along the ocean floor wrapping round and splitting to join other major curr... |
[
"Question regarding gravity, relativity and string theory"
] | [
false
] | I've been watching hours of lectures on the internet regarding relativity, quantum mechanics, string theory etc and (despite my feeble attempts to understand it) a question occurred to me. String theory (m-theory) attempts or can attempt to describe the weakness of gravity when compared to the other forces -- that grav... | [
"If M-theory is wrong, it's entirely possible that gravity being weak is just a fundamental fact of nature. There are lots of things like this. Why does a proton have the mass it does? Is there an underlying reason as M-theory would say, or is it just a fundamental measurement in our universe.",
"I don't think it... | [
"Well, if the sister brane's gravity affects our matter, then our gravity should affect its matter. In essence, the \"galaxies\" of the sister brane should occur and clump \"near\" (whatever that means) the galaxies of our brane. So we would predict to only see dark matter interactions near galaxies, not all over t... | [
"Sure, it would be more concentrated near our galaxies, but there's no reason the sister brane would be 1:1 with all of our galaxies. Presumably the quantum fluctuations that occurred during their period of inflation would be different than ours, and so they would have galaxies in regions where we would only have e... |
[
"Why is space-time distortion due to gravity always shown as planar?"
] | [
false
] | It seems like a bad way to represent gravity because it works in three dimensions, not just two. Is this simply because it would be impossible to visualize otherwise? | [
"They wouldn't necessarily have to be 4 spacial dimensions, you could do a 3 dimensional heat graph kind of representation with color representing the relative distortion of space-time due to massive bodies... but it would be difficult to ALSO visualize the source of the distortion effectively.",
"The reality is,... | [
"They wouldn't necessarily have to be 4 spacial dimensions, you could do a 3 dimensional heat graph kind of representation with color representing the relative distortion of space-time due to massive bodies... but it would be difficult to ALSO visualize the source of the distortion effectively.",
"The reality is,... | [
"Its actually a very loose 3D representation, but kind of effective. Its just a bunch of 2d projections overlayed onto each other."
] |
[
"If alcohol makes you dehydrated, why is urine clear in colour (while drinking a lot), which indicates that you're hydrated?"
] | [
false
] | During a big night out, most of us guys will know that our urine gets clearer in colour the more we drink. I got taught that clear urine means that you're hydrated. So, how come we get dehydrated from alcohol? Are we just urinating all the water that's in the alcohol, leaving all the sugars etc. which makes us dehydrat... | [
"Perfect, clear explanation. Thanks for the info! "
] | [
"Perfect, clear explanation. Thanks for the info! "
] | [
"Also slightly helpful, vasopressin is commonly known as anti-",
" hormone (ADH). "
] |
[
"How/when would we know that there were no more elements in the universe?"
] | [
false
] | Also is it even possible to know if there are no more elements left or is there just an infinite amount of elements? | [
"By this I assume you mean that you are referring to some of the new additions on the Periodic Table that are artificially created? If not, here is a basic explanation.\nThere are 92 naturally occurring elements found on Earth, from hydrogen to uranium and each is defined by its number of protons. So why, you may a... | [
"Likely not, because even if the outer electron shell was filled, you would still have a very large and unstable nucleus. This nucleus would be unstable due to its size and the inability of the nuclear forces to hold the nucleus together. ",
"There is a theoretical range of elements that exists called the \"islan... | [
"Is it possible that a future lab-created heavy element (such as one with a full outer electron shell) could be reasonably stable (not in the millisecond timescale)?"
] |
[
"I've heard a lot about the value of mindfulness meditation recently and have started to practice myself. However, I've been struggling to find how much and how often is required to see a real benefit."
] | [
false
] | null | [
"I've suspected for a long time that some people are good at meditating and some aren't, and that those that are predisposed will be the only ones that see any benefit (because the others won't be able to do it, or maybe it will cause more frustration).",
"In short, does meditation benefit everybody, or just the ... | [
"I'm not an expert, but this is the ",
"first paper ",
" returned by Google Scholar. It has around ",
"1000 citations",
" listed: that's huge! Of course they could all be calling them out, but plenty to get a reasonable literature review happening anyway.",
"The study I have linked reports changes in brai... | [
"I've been struggling to find how much and how often is required to see a real benefit. ",
"The default for people starting meditation, living ordinary lives, is 1/2 hour per day, every day that you can. ",
"Over the first month you can expect to see some effects that you consider to be benefits, and other thi... |
[
"I'm not a crater hunter but what you think of the images of map I attached ? I wonder if it is a elongated crater."
] | [
false
] | null | [
"Yes, I'm aware of what oblique impact craters look like, the point is that on Earth, there are a variety of processes that can produce topography of similar shapes so knowing something about the bedrock geology of the area in question is essential to rule out more likely reasons for the topographic expression. I s... | [
"Yes, I'm aware of what oblique impact craters look like, the point is that on Earth, there are a variety of processes that can produce topography of similar shapes so knowing something about the bedrock geology of the area in question is essential to rule out more likely reasons for the topographic expression. I s... | [
"There needs to be more context for the possibility of an answer, ie where is this? It doesn’t look like a crater. It looks like topography reflecting deformed stratigraphy, for example a fold-thrust belt."
] |
[
"At what rate are we experiencing time, relative to CMBR?"
] | [
false
] | This was really tricky to put succinctly in the title. I did a search but didn't quite find what I was looking for. Okay, so from what I've read we're hurtling through the universe at 370 kilometers per second relative to CMBR and from what I understand time moves slower the closer you get to the speed of light. So, gi... | [
"t'=t/sqrt(1-(v",
" /c",
" )). So for a v of 370,000 m/s, that gives a rate of 1.000000760556423223785 seconds in our frame for every second in the \"stationary\" frame. So, time in our frame is passing at 99.9999239% the rate of the CMB stationary frame.",
"Note: that is with respect to an observer in the CM... | [
"And in terms of our gravitational field relative to freefall, it adds another two parts per billion time dilation."
] | [
"You phrased your question in two subtly different ways. The correct way, at the end of your post, \"how slowly are we experiencing time, relative to an observer who is stationary to [the] CMB?\". That's a valid question and has been answered already.",
"But in the title of your post you asked how slowly we're ex... |
[
"Nuclear reactors on shorelines"
] | [
false
] | I'm not sure if this is just confirmation bias, but it seems that every time I have seen a nuclear reactor outside of a landlocked country, I've seen it on the shore of a large body of water. Is there a reason for this? The best I could think of was that it was for emergency coolant reasons. Of course, I don't even kno... | [
"Not even emergency coolant, just regular coolant. Non-nuclear thermal generating plants are also often built on shorelines to use the water as coolant. (Water for steam has to be purified even from a municipal source so it's probably not taken from a river.) It's not contaminated as it's kept separate from everyth... | [
"The reactor coolant is pure, fresh water. But that's a closed loop. Reactor-turbines-condensor and back. Depending on the reactor type, the turbines may on a second loop with a heat exchanger to the first loop. For this you use pure, fresh water of course. The low-pressure steam that's coming out of the the turbin... | [
"Nuclear reactors do use a lot of water (both coolant and steam turbines, I assume). Seems like salt water would be suboptimal, but maybe it's fine."
] |
[
"Is a gene dominant over a recessive gene because it is better for survival?"
] | [
false
] | The reason I'm asking is because if it is true that genes that are the most easily expressed are the genes that allow you to survive better, then it would make sense to want to have a child with someone with a genetic background completely different to that of your own. As to give you child the broadest range of genes ... | [
"The dominance of different alleles of a gene is largely determined by the nature of the protein that it encodes. For example, defects in structural proteins generally manifest as dominant traits because being heterozygous results in defective protein synthesis, which disrupts the native healthy protein. On the oth... | [
"Gene expression and thus traits being dominant or recessive, is based on protein and gene interactions. There is no inherent link between this and genetic fitness."
] | [
"Thanks, this makes sense. But then is this dominant defective protein structure just a fluke? ",
"Would it make sense to say that the majority of dominant traits that end up being expressed are actually good for survival?"
] |
[
"When quantifying gene expression why analyze RNA vs DNA?"
] | [
false
] | null | [
"DNA tells you almost nothing about gene expression. One gene could be 'switched off' and not be transcribed at all (0 RNA) while another could be highly expressed (millions of copies of the complementary RNA). Looking at the DNA will only tell you that there is one of each gene. By looking at the RNA you can see i... | [
"RNA is the intermediary between the DNA blueprint and protein synthesis. Not every gene in a strand of DNA is transcribed into RNA, so analyzing RNA allows is to see what genes are active, and therefore what proteins are actually being made. Every single cell (with a few exceptions) has a ",
" copy of ",
" you... | [
"A good place to begin is the idea of the central dogma. The ultimate goal of DNA is to produce proteins. The genes contained in you DNA are transcribed into RNA which can be later translated into proteins: DNA -> RNA -> Protein.",
"You can't really quantify gene expression directly through DNA. The number of gen... |
[
"How do RNA, enzymes, etc. know where to go and what is their method of movement."
] | [
false
] | Throughout my study of high school and college biology, it seemed that proteins, nucleic acids, RNA, etc. had an intrinsic guidance system that told them where to go. How exactly do molecules inside a cell know where to go and how do free floating molecules move? Do they just float aimlessly until they perhaps reach th... | [
"They do not \"know\" where to go.",
"They move around randomly by diffusion (a look at \"SnapShot: Key Numbers in Biology\" ",
"(ref)",
" says an average protein takes ≈10ms to traverse an E. coli cell and ≈10s to traverse a HeLa cell, a small metabolite moves ≈100 times faster).",
"As they move they inter... | [
"Yup, many molecules \"just float aimlessly\"--but they float aimlessly ",
" fast. ",
"Some are also actively transported along the cytoskeleton by motor proteins. "
] | [
"\"Within each motor protein class, movement speeds vary widely, from about 0.2 to 60 μm/sec for myosins, and from about 0.02 to 2 μm/sec for kinesins.\"",
".",
"For reference an animal (HeLa) cell is about 20 um in diameter. So some sprint along, others slowly shuffle. \"Walk\" is more meant to describe how th... |
[
"From an environmental standpoint, is it better to use (recycled) plasticware/disposable utensils, cups and plates, or wash dishes by hand?"
] | [
false
] | You guys said not to apologize for asking a stupid question, so I won't apologize, but I'm legitimately curious. Given the recycled plasticware on the market, and some of the biodegradable stuff, what is more environmentally friendly-- to use these products, or to wash dishes by hand or in the dishwasher? I just feel l... | [
"I find it really hard to believe that disposable utensils could be produced, distributed to stores, delivered to my home and then taken away to a recycling facility for less energy than it takes to pump and heat a sink full of water."
] | [
"It takes ",
"about 24 gallons of water",
" to make a pound of plastic. So it really depends on how much you are using to wash versus the amount of waste you produce.",
"Edit; If water waste is all you care about."
] | [
"It's not really water that's being wasted, it's the energy used to treat that water and then pump it to your home. Why shouldn't you include heating the water in this cost? Or the power used by the dishwasher if you have one?"
] |
[
"What psychological phenomenon is happening when we can \"hear\" specific types of soundless optical illusions?"
] | [
false
] | Let's consider the . This looping video has no sound but there's a very distinct that I can hear and somewhat "feel" around an ambiguous portion of my left eye. Others (namely from where the source of this was posted) unanimously agree that they can also "hear" it so it's not likely that I'm imagining. EDIT: The link d... | [
"Short answer: you're expecting to hear a thump, so you hear a thump.",
"Long answer: You're constantly making predictions about your sensory input. This is why the lack of sensory input results in hallucinations--you start predicting on the basis of pure noise. Take a dip inside a sensory deprivation tank, and y... | [
"Well, firstly you ",
" imagining the sound and feeling. The fact that others do simply means that they are imagining it as well. Personally I don't hear anything (nor for the skipping pylon ",
"https://www.youtube.com/watch?v=b--kczcf4AI",
").",
"The explanation is an example of \"top-down processing\". T... | [
"Thank you. And for reference, ",
"here's the video",
" that was supposed to post properly the first time around. Not sure what happened there."
] |
[
"Why is proving or disproving the Reimann hypothesis important?"
] | [
false
] | So after years of being a lawyer after being awesome at math in high school, I've been dusting off my old skills by watching a lot of youtube videos recently. After years of hearing vaguely about the Reimann Zeta function, I feel like I have a good handle on what the problem is. But I seem to be butting up against my i... | [
"The Millennium Prize Problems, of which the Riemann Hypothesis is one of seven, are problems in math that were chosen at the turn of the Millennium whose solution expected to bring their respective fields to the next level. Each of them was conjectured after a long line of mathematicians thinking about a topic, an... | [
"It means that we can reconstruct the function from its zeros, and that the information in the function is expressed in the zeros. A much more mundane example of this can be seen through polynomials. If you know the zeros of a polynomial p(x), then you can find the slope at x=0 though simple combinations of the zer... | [
"Thanks for an awesome answer. A few followup questions:",
"The absolute furthest that they can get is the edges of the critical strip, at Re(s)=1 and Re(s)=0, a zero here would be the worst case.",
"Maybe I don't understand you here, but wouldn't a zero here be the ",
" case? If the deviation from the 1/2 li... |
[
"Why isn't the mosquito an intermediate host for HIV/AIDS? Can it be?"
] | [
false
] | I am reading by R.D. Lawrence and I just learned mosquitos are an intermediate host for (common dog heartworm) as well as malaria and encephalitis. How does the mosquito transfer the disease? Is it through blood contact? If so, is it theoretically possible to contract HIV/AIDS from a mosquito bite if he is carrying the... | [
"HIV is an extremely fragile virus and it cannot use intermediate hosts -- it doesn't infect anything other than humans.",
"Some viruses, for instance influenza, can survive outside a host for extended periods of time (hours, days, or even weeks in the case of influenza, if the conditions are favorable). Some vi... | [
"The conformation of the virus proteins exists at around human body temp. For viruses to survive outside, it needs to evolve proteins that are resistant to denaturing or misfolding from leaving their ideal temperature range. There's a loooot of other things that affect it too, but this is one of the big ones."
] | [
"But what is it specifically about the host body that supports the virus's existence? Temperature? Blood composition? "
] |
[
"I have three lasers, red, green, and blue. I was playing with a spectrometer and I found that the blue and green lasers are outputting two, not one, wavelengths of light. Why is that?"
] | [
false
] | [deleted] | [
"It would help if you tell us what kind of lasers. (Like, diode lasers, gas lasers, fiber lasers, ... A datasheet or spec sheet for each laser would be even more helpful)",
"The blue curve is easy to explain if that laser is actually an 800-ish nm laser with a frequency doubler to achieve ~400 nm. This is a prett... | [
"So, as ",
"u/thephoton",
" has explained, the two peaks for the blue spectrum is easily explained by the fact that it is easy to make diode lasers around the 800 nm mark and then ",
"frequency doubling",
" the light with a small second-harmonic generation crystal (either ",
"BBO",
" or ",
"KTP",
",... | [
"Are you sure you're not looking at one of the other diffracted orders?"
] |
[
"Can a commercial airliner successfully complete a loop-de-loop? And with what factors? (e.g. No passengers)"
] | [
false
] | [deleted] | [
"I think the A380 video was achieved by turning the camera upside-down"
] | [
"I am an aircraft systems engineer, I worked on military avionics. Many of my coworkers work in the commercial field, they are generally told to engineer out pilot shenanigans as much as possible. Airbus does not have manual reversion on all control surfaces so it is not possible to do a loop, in order obtain the n... | [
"I am an aircraft systems engineer, I worked on military avionics. Many of my coworkers work in the commercial field, they are generally told to engineer out pilot shenanigans as much as possible. Airbus does not have manual reversion on all control surfaces so it is not possible to do a loop, in order obtain the n... |
[
"Why does an acid or base cause pain to the body?"
] | [
false
] | I understand the structure of acids and bases and how they react in various mechanisms. However, one thing I've always wondered is , say, HCl hurts when it gets on your skin. Same goes for any acid or base. Are there varying mechanisms depending on the structure of the acid? Is it that the acid/base is directly causing... | [
"Here's what I understand. An acid donates protons. These protons want electrons, so they \"steal\" them from your tissues. Try searching to be sure."
] | [
"Bases donate electrons, and acids accept them. That's a more universal definition of acid and base.",
"Edit: I understand the chemistry (I'm a chemistry major), I was just curious as to ",
" that can cause pain."
] | [
"The Lewis acid theory says that acids and bases receive/donate electrons. The Arrhenius theory says that acids and bases donate/recieve protons. ",
"Did I answer the part about pain well enough? If something is destroying your tissue you new to know about this, so pain signals are sent to the brain."
] |
[
"Why is Ebola not as contagious as, say, influenza if it is present in saliva, therefore coughs and sneezes ?"
] | [
false
] | Reading this in discover magazine "The virus does not aerosolize like measles or influenza, and thus, you cannot get it simply from being in the same room, subway car, or aircraft cabin as an infected person who coughs or sneezes." Why is this and could the outbreak give rise to a variant which is more transmissible ? | [
"All viruses differ in the protein/lipid coat (capsid) that surrounds them and gives them protection - you can see here for a review of the essential parts of a virus - ",
"http://www.breakingbio.org/ebola-influenza-and-aids-oh-my-viral-pathogens-101/",
"\nThis capsid gives the virus protection and allows them ... | [
"It really does't have to do with the capsid. Ebola can be aerosolized in the lab. If monkeys breathe in this aerosol, they will get Ebola and die. So, the capsid can protect the virus just fine, at least for a time. Yes, other viruses are more hardy in the environment than Ebola, other are less. But Ebola can... | [
"The upper respiratory tract is not an efficient site of replication for Ebola. Ebola is not shed in high quantities into the mucosa of the nose and mouth.",
"This is the primary reason and should be on top. The capsid for ebola isn't especially relevant for this. Technically it CAN be transmitted as an aerosol, ... |
[
"Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! ... | [
"[Biology] How do macrophages know when a cell is too 'old' or damaged, and is ready to be 'eaten'?"
] | [
"Cells put some proteins and enzymes on their membranes for display. When they get old, their enzymes and proteins also look \"old\" (not as well made). Specialized immune cells (I think T cells) constantly scan these displayed proteins, and when they notice something unusual, foreign or wrong, they mark the cell f... | [
"The only thing that comes to mind is that there is some eye-strain-induced headaches that you can get from staring at a computer screen / TV for a long period of time. This strain occurs because you focus at a fixed distance for a long time, often without blinking."
] |
[
"Creating Earth like gravity in a spaceship"
] | [
false
] | Ignoring magical devices and a constant thrust from an engine how could you create earth like gravity in a space ship. My only thought would be a spinning wheel. If this is the case, what size would be best suited, and what speed would it need to rotate? Would it be possible to even build it due to the forces involved? | [
"This question seems to have been studied in some depth. See ",
"http://en.wikipedia.org/wiki/Artificial_gravity#Rotation",
" and the rest of the article.",
"Referring to Columbo1's concern, the initial spinning-up of the wheel would cause the rest of the structure to spin in the opposite direction. Also, hav... | [
"A spinning \"can\" (hollow cylinder) can produce the artificial gravity. The diameter would need to be large enough that area for human interaction would be a small enough fraction to keep the 'gravity' constant, as moving towards the center would result in a decrease in 'gravity.' I remember solving this question... | [
"Wouldn't the force of the wheel spinning cause the ship to spin?"
] |
[
"Why not let the Fukushima reactors simply melt down?"
] | [
false
] | From Reddit and other sources I heard that the "worst case" for this type of reactor would be a meltdown. In that situation, the core would partially or completely melt and sink into the concrete containment structure below it. It would be a nasty cleanup but not much radiation would escape. Instead, the Japanese worke... | [
"The cleanup after a meltdown would cost a fortune. If it can be prevented while releasing only trivial amounts of radiation, that's probably a good trade."
] | [
"No, but A) the people who run the power plant don't have to pay that cost and B) the whole region was already in chaos due to the tsunami."
] | [
"A worst case scenario at a nuclear plant always always always involves the breach of containment. All of those reactors are housed in a containment chamber which ",
" be able to withstand the heat/pressure of a melt down. I believe they are unable to failure test these things, due to the nature of the failure re... |
[
"Can we set stars from other galaxies with the naked eye?"
] | [
false
] | null | [
"You cannot see individual stars (including in ",
"satellite galaxies",
" to the Milky Way). You can see the collection of stars together looking like a blob of light, which means that you can see things like the Andromeda Galaxy with your naked eye, for the reasons listed in the link."
] | [
"Thanks for the explanation mate. "
] | [
"We cant see main sequence stars, however under one circumstance it is possible to see stars outside our galaxy.",
"In 1987 a supernova (SN1987A) occurred in the tarantula nebula in the Large Magellanic Cloud. This is a dwarf galaxy which orbits our milky way. ",
"The Supernova was visible to the naked eye in t... |
[
"Can anyone explain to me the impact this asteroid has on the astronomy community? (or if it has much significance)?"
] | [
false
] | video shows asteroid 2005 YU55 that will be closer to the earth then the moon ever gets. I'm curious if it will upset the balance of the moon & earth to some sort of occurrence where the moon smashes into earth. :) Thanks. | [
"\"Oh cool, an asteroid\" pretty much sums it up. Its not a collision risk or otherwise interesting. "
] | [
"The asteroid is only 400 meters in diameter. It doesn't have enough mass to make any significant impact on the orbits of either the earth or the moon.",
"Assuming it were a solid iron sphere (likely it's a much less dense collection of rock), it'd have a mass of roughly 2.56*10",
" kg. the moon has a mass of 7... | [
"Well, something got much closer in 2004. I don't know how often it happens though.",
"A lot, apparently",
", but I think most of those are smaller than Mr. YU55."
] |
[
"Are infrared light and heat energy the same thing? Or do things that give off infrared light just happen to be warm?"
] | [
false
] | [deleted] | [
"All matter gives off electromagnetic radiation; all electromagnetic radiation incident on other matter causes the atoms composing that matter to move more. Heat is the movement of atoms.",
"Infrared is special because most of the stuff on Earth radiates primarily in the infrared spectrum and because IR is very g... | [
"The second one, but reworded differently. Radiation is emitted from some sort of vibrations/energy transitions occurring in the atoms/molecules that make up whatever stuff. Radiation emitted due to thermally excited molecular vibrations happen to fall in the IR range, at 'moderate' temperatures. The hotter it i... | [
"The second one."
] |
[
"Force mediators and C"
] | [
false
] | We know the speed of light, yay. Gravity also propagates at the same rate. What about the strong force and the weak force? What speed to they propagate at? If I was told to guess, I would guess it would also be C. So would it be more accurate to call the "speed of light" the speed of boson propagation? | [
"The strong force (mediated by gluons) propagates at the speed of light. The weak force (mediated by the W",
" and Z",
" bosons) propagates at significantly less, because the bosons have mass, and because of this, the weak force is a short range force.",
"The strong force is a short range force for another r... | [
"The strong and weak forces were not formalized by first taking a classical wave model and then quantizing it, so we can't directly look at the speed of transmission that way.",
"Looking directly at the quantum field theory model, gluons (strong interaction) don't have mass, and can be expected to be transmitted ... | [
"So I would imagine there is a distance limit on the Strong Force then?"
] |
[
"Do pupils dilate and constrict in unison?"
] | [
false
] | null | [
"Okay everything in this thread is a lie. Assuming you don't have nerve damage to your optic or occulomotor nerve, both your eyes dilate/constrict at the same time. It does not matter if both eyes or only a single eye receive light input; both SHOULD dilate/constrict equally. This is known as the pupillary light re... | [
"The eyepatch myth works, but it's not because of the pupils being unequally dilated. It's because the cone cells in the covered eye aren't bleached by the bright light. "
] | [
"The eyepatch myth works, but it's not because of the pupils being unequally dilated. It's because the cone cells in the covered eye aren't bleached by the bright light. "
] |
[
"What affects the lifespan of memory T and B cells?"
] | [
false
] | I got curious and have been trying to find the information but I just couldn't find it. I know that memory lymphocytes formed after infections. But I didn't know why some live long while some are not and what makes them like that. This shows different efficacy of vaccination so I just wondering why efficiency become le... | [
"This is a very complex issue with no clear answer. The half-life effect is still the case but this just says that memory cell pool against any specific pathogen will slowly (it varies) decrease over time but it doesn't say how. Some times this decrease still means protection over decades which practically means li... | [
"Have experts been saying that recently?",
"That was the best guess a few months ago: ",
"But it's turning out that the mRNA vaccines are providing robust immunity to the variants (as you said) - most experts I follow on Twitter etc. are excited that we definitely do *not* have an immediate pressing need for va... | [
"Do you know why experts estimate that we will need booster shots every 2-3 years against covid19? All the studies I have seen so far shows that even though antibodies decrease, thanks to memory cells immunity is still strong in most of the individuals after 6-8 months of infections. I also do not hear these reinfe... |
[
"Can I kill dust mites with my mass?"
] | [
false
] | Can I crush microscopic dust mites by walking/lying on them for example by walking on carpet or getting into bed? If so how many, and if not, why not? | [
"In a bed or on carpet the dust mite would simply be pushed into that material as is deformed around them. Tiny creatures with exoskeletons are incredibly difficult to crush because you need to be very precise. If a dust mite were to be sitting on a slab of marble with no imperfections on the surface, it could be c... | [
"Relevant law:",
"Square cube law",
" (wiki)",
"Decent layman explanation"
] | [
"Don't get me wrong, but i don't think there are many peer reviewed works talking about how to crush fleas with your hands."
] |
[
"What happens to gravitational potential energy of objects that are destroyed by a star?"
] | [
false
] | Apologies that my question sounds a bit science fiction, but I am genuinely curious as to the outcome. To elaborate on the situation, if a planet, barren except for a one kilogram weight at ground level were to be left until incinerated by the star it orbits, all energy is consumed by the star as chemical potential en... | [
"Anything that falls toward something, whether a rock falling to the Earth or a planet falling out of orbit toward a star converts its potential energy to kinetic (motion) energy. When the planet reaches the star, it no longer has any potential energy; it has been completely converted into kinetic, which is quickly... | [
"When the planet reaches the star, it no longer has any potential energy",
"Since potential energy is defined as the potential difference between two arbitrary points, this statement of yours ",
" is misleading.",
"Potential energy is not an absolute value. I can assign an object on the surface of a planet a ... | [
"When considering gravitational potential energy, it is common practice to set the zero of the potential at the surface of the planet, or in this case, the surface of the star."
] |
[
"Can someone explain what enthalpy really is in chemistry, is it like heat or what??"
] | [
false
] | null | [
"The change in enthalpy during some process is the heat absorbed during that process, assuming the process takes place at constant pressure (as is often the case in a chemistry lab)."
] | [
"What if it's not in constant pressure??"
] | [
"Then the heat absorbed is not equal to the change in enthalpy. The change in enthalpy is",
"dH = T dS + V dP.",
"T dS is the heat absorbed during the process.",
"So dH = Q + V dP. At constant pressure, dH = Q, but if the pressure is not constant, you still have the V dP term as well."
] |
[
"How can I distinguish between different instruments in an song? Or distinguish different voices in a crowd?"
] | [
false
] | The way I understand it, our ears can only hear one sound at a time, at least in an abstract sense. Our ears pick up a combination of fundamentals and harmonics, some providing constructive or destructive interference, and the unique combination of this interference is why a saxophone sounds like a saxophone and a trum... | [
"This problem is called the cocktail party effect. It works because you have two sensors, your ears, which capture sources at different levels. In a statistical sense, the noises are independent of one another. You brain solves an unmixing of these these components using an unknown algorithm.",
"Computationally, ... | [
"Yup - it's the driving mechanism behind CDMA radio modulation. I I wanted to clarify about 'as many sensors as there are components to unmix' - in this case, even when you listening to a room full of people, your brain separates the sounds into 'who I'm listening to' and 'everything else', a sort of one-versus-man... | [
"You may already know much of what's below, but it's important to be sure you have the basics right. ",
"You are partly correct about the ear. In the ear the waveform that entered is converted into a series of frequencies and sent to the brain. In the Cochlea there's a huge array of 'sensors' for a huge number of... |
[
"Is it possible that only 4 moose imported to Newfoundland in 1904 could produce a viable modern population of 110,000 today?"
] | [
false
] | null | [
"Certainly it’s possible, though not inevitable. Small inbred populations can persist in spite of small founder populations - the classic examples are ",
"island foxes",
", and island populations are the best studied. ",
"Populations can survive inbreeding better if they have a longish history of smallish (bu... | [
"Keep in mind moose routinely cross water. It isn't totally impossible they can get to Newfoundland from the mainland on their own. The shortest distance between Newfoundland and the mainland is 17.5 km which is not exceptional for the distance moose can swim."
] | [
"And two of them, with a length of seaweed between them, could absolutely bring along a coconut."
] |
[
"What are the affects of bringing resources to Earth from other planets/asteroids?"
] | [
false
] | Is there a point to where this can be a negative affect? If we mined metal and brought it back to Earth over thousands of years, could this extra weight change our orbit/rotation? What would be the affect of adding water to Earth's environment? should there be a limit? This question stems from Planetary Resources plans... | [
"effects"
] | [
"...over thousands of years.",
"In 'thousands of years' scientific advancements would surely have come far enough to compensate for any gravitational effects of additional matter brought back to Earth. ",
"Even more so, society would have spread throughout the solar system and/or galaxy at this point, which inv... | [
"Let's not forget about the mass you lose when you burn fuel to get where you need to go. The fuel you'd need to get a light year away would be absolutely massive. I don't know if all mass is conserved, but the earth has to lose mass so you can burn fuel and eat and continue to produce waste, etc.; none of these ... |
[
"With a lack of friction, could I roll a ball infinitely or would it fail to move?"
] | [
false
] | null | [
"Oh, I see what you are saying here. You're talking about the friction between the cue tip and the ball.",
"If two perfectly round spheres were to collide in orbit with zero initial rotation, the contact between them would be a single point. Let's say ball 1 is at the origin and ball 2 is coming down a line par... | [
"To answer my own question. The normal force to the lower half a ruler does not go through the center of mass.",
"A collision of two balls on a single contact point with no friction creates a normal force through the center of the balls, dictating the direction of travel based on the impact parameter."
] | [
"I believe that the premise here is that the object exerting the force on the ball has friction, but not the surface on which the ball is sitting.",
"In the situation you described (where the \"cue\" has no friction either), you are correct - the ball wouldn't rotate. It would simply slide in the direction of a ... |
[
"Do Anti-inflamatory medications slow the healing process?"
] | [
false
] | A common refrain when small injuries (like a tweak to a back muscle) occur is to take ibuprofen, which in theory reduces inflammation. But from my understanding, inflammation is your body's natural reaction to an injury and is meant to heal you. So while they may have short term pain relief effects, are these drugs slo... | [
"Yes, ibuprofen has been shown to negatively effect wound healing. Furthermore a recent study suggests that by interfering with the natural healing cascade ibuprofen also contributes to the development of chronic pain.",
"https://www.science.org/doi/10.1126/scitranslmed.abj9954",
"Tylenol does not inhibit infla... | [
"I'm going to take the liberty of answering your question as well as the unasked corollary- \"should I avoid taking NSAIDs in order to maximize my body's healing potential?\" Please indulge me in this.",
"The short answer is: yes, anti-inflammatories probably impair the healing process somewhat. Inflammation is t... | [
"\"acetaminophen also reduces empathy for other people’s suffering\" Win-win /s",
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6455058/#abstract-1title"
] |
[
"Since batteries are essentially reduction-oxidation reactions, why do most batteries say not to charge them since this is just reversing the reaction? What is preventing you from charging them anyway?"
] | [
false
] | Edit: Holy sh*t my first post to hit I saw myself there! | [
"One of the necessary conditions for a battery to be rechargeable is that the underlying chemical changes that occur during an electrical discharge from the cell must be efficiently reversed when an opposite electrical potential is applied across the cell. In nickel-cadmium (NiCad) batteries, for example, the Cd(OH... | [
"One of the other problems with charging ‘non rechargeable’ batteries is that the materials may not deposit uniformly onto the anode or cathode when charging. So what happens then is you can create a short circuit inside the battery, which if your charger is not intelligent enough to detect, can cause a lot of curr... | [
"Interesting. ",
"I remember recharging non-rechargeable batteries as a kid ( I didn't know they were not rechargeable) several times and it worked really well until my father said I shouldn't do it because it could explode.",
"Does the risk of fire increase for each charge on non rechargeable batteries?"
] |
[
"Can someone explain to me the Schrodinger Equation?"
] | [
false
] | I'd really like if someone can explain to me what the Schrodinger equation tells us, what each of the variables and constants are for, and when the equation is used? | [
"Well, insofar you can know the properties of a system (in QM you can't predict the outcome of a ",
" measurement, but you can predict the probabilities of the various outcomes and related statistical properties like the average result), the Schrödinger equation tells you ",
" about a physical system. ",
"It'... | [
"Hmm, that's a bit of a tall order. I mean, I ",
", but there are so very many good popular-scientific books explaining all that - not least from a historic-development perspective (which is also how most textbooks approach it). ",
"But to do it as shortly as possible: The specific problem they were trying to s... | [
"Hmm, that's a bit of a tall order. I mean, I ",
", but there are so very many good popular-scientific books explaining all that - not least from a historic-development perspective (which is also how most textbooks approach it). ",
"But to do it as shortly as possible: The specific problem they were trying to s... |
[
"If the deepest we have drilled into earth is 7.5 miles, not exceeding earths crust, how do we have detailed descriptions/illustrations of what the other of the thousands of miles look like? For example earths core, the mantle and inner core."
] | [
false
] | null | [
"Seismic waves. Earthquakes.",
"When there is an earthquake different waves will move through the earth, through the different parts of the earth, at different speeds and in different ways. We can measure this at different points and begin to paint a picture. What you are seeing on your seisometre took x time lon... | [
"Others have touched on the seismology side - reflection and refraction of seismic waves, detected by hundreds of seismic sensors around the globe give us something similar to an ultrasound you get during a pregnancy, but with much lower frequencies (and therefore a resolution of tens of kilometers for most of the ... | [
"When the medium a wave travels through changes density, the wave refracts. This is why when you look through a glass of water - even a rectangular glass - the light is bent. The water and air are different densities.",
"So if there's a loud sound wave propagating through the earth, and we have sensitive micropho... |
[
"Why is the Oort cloud spherical?"
] | [
false
] | ...and not an accretion disk? | [
"The Sun formed from a collapsing molecular gas cloud, which itself had some net angular momentum. As the rotational velocity of this collapsing gas cloud increased due to conservation of angular momentum, it flattened out into the circumsolar disk.",
"It was in 1950 that ",
"Jan Oort first suggested",
" that... | [
"First, Oort cloud is a bit hypothetical, those objects are far enough away that they are not catalogued. At those distances, Sun looks like just a bright star, how do you observe a object so dimly lit?",
"That said, assuming they are there, they wouldn't really have had time to form a accretion disk. The objects... | [
"The explanation is bested only by your /u/. ",
"Excellent work, neighbour."
] |
[
"Does dietary cholesterol raise serum serum cholesterol levels?"
] | [
false
] | An undergraduate in a health related field here I’ve come across some really confusing stuff regarding this topic. I’ve always been kind of health conscious from a young age and interested in this kind of stuff. I was under the impression that saturated fat and cholesterol both contribute to raising serum cholesterol ... | [
"Here is what an NIH paper concluded:",
"\"The current literature does not support the notion that dietary cholesterol increases the risk of heart disease in a healthy individuals. However, there is an ample evidence that saturated fatty acids and trans-fats increase cardiovascular disease risk. The fact that die... | [
"First: Englisch is not my native language, but i try to Answer as good as i can. As far as i know there are some \"hyper-responder\", where the cholesterol from food can influence the bloodcholesterol. But there are also some \"none-responder\" where the food cholesterol has no influence. And because You don't kno... | [
"Same with me I tend to avoid high saturated fat and cholesterol dense foods as well, the data in terms of longevity tends to suggest moving towards a predominantly plant based whole foods diet is best ."
] |
[
"Is there any science behind why different types of beers should be drank out of different mugs/glasses/etc, or is it just a gimmick perpetuated by beer snobs?"
] | [
false
] | [deleted] | [
"http://en.wikipedia.org/wiki/Beer_glassware",
"This article explains the reasoning behind many of the glasses."
] | [
"And sometimes questions get answered with one simple link."
] | [
"I know some glasses have a straight neck, so that when you drink, the part that is on the bottom, rushes throught it with a higher velocity and ends up mixing with the rest of the stuff. "
] |
[
"Just teaching my kids how to ride bikes this week. Can anyone explain the relationship between speed and balance?"
] | [
false
] | [deleted] | [
"Oh wow, this is a very hard question to answer. ",
"Gyroscopic forces",
" are definitely there keeping the bike stable, but at higher speeds, they aren't even necessary. The physics behind it are debated even today, but a ",
"study",
" has shown that speed seems to allow bikes to counterbalance tilting r... | [
"when i first started learning, and after a bit of experience, what my brother did was screw on the training wheels in a way that they weren't touching during normal riding, but if you are about to fall or turn a corner, they rouch the ground and stop you. so most of the time you are just riding a bike like normal,... | [
"when i first started learning, and after a bit of experience, what my brother did was screw on the training wheels in a way that they weren't touching during normal riding, but if you are about to fall or turn a corner, they rouch the ground and stop you. so most of the time you are just riding a bike like normal,... |
[
"If solids are better conductors of sound than gas, how do earphones block sound? What about soundproof walls?"
] | [
false
] | null | [
"Sound propagates better though solids and liquids than through air, as it depends on the density, but it doesn't pass well through discrete boundaries in substances. For example if you are hearing someone in the next room shouting, then it sounds more quiet as it has to pass through the wall-air boundary twice. If... | [
"And also, some materials, despite being solid, are sound insulators/isolators. As boom_doggle said, one thing is the loss of energy when changing mediums. A lot of headphones aren't made of a uniform heterogeneous solid material, but rather a porous design with a lot of air pockets. This allows for the 'sound i... | [
"Oh, so soundproof walls would have empty spaces between two walls?"
] |
[
"Why does lens flare happen?"
] | [
false
] | Why do we see this? I'm only in my first year at Uni so I know a little geometric optics and a bit of wave optics (up to deriving the Rayleigh limit for a single slit). I just can't figure out why this happens | [
"Glass (even coated glass) reflects a small amount of the light hitting it rather than just transmitting it or absorbing it. All camera lenses in common use since at least 1920 are multiple lenses to reduce chromatic abberation, which provides for internal surfaces for the light to reflect off of. Normally, the... | [
"Just to add:",
"A lens flare almost always takes the shape of the lens's aperture. On cheap camera will see 3 or 4 sided flare while on very expensive lenses the flares are almost circular.",
"The reason for this is that it is often one (or more) of the glass elements behind the aperture reflecting light forwa... | [
"most digital sensors can only see 2-3 \"stops\" of light from what reads as black to white",
"http://www.dxomark.com/index.php/Cameras/Camera-Sensor-Ratings/(type)/usecase_landscape",
"Was that a typo or do you mean something else than what I think you mean?"
] |
[
"What do we know about the cores of gas giants?"
] | [
false
] | How much do we know about the cores of our gas giants? How possible/plausible is it that they actually have large super earth sized rocky cores? I mean Jupiter must have gobbled up tons of asteroids through out its formation.. wouldn't the gas giant have formed around a rocky planet first?? I've read some about the "m... | [
"This",
" paper describes some of the most up to date observational data we have of Jupiter and Saturn. There is no solid core just a progressively dense mush.",
" ",
"It is unclear if this is due to erosion of an old core or formation. Some more modern modifications to accretion have considered mushy planite... | [
"There will be settling of heavy elements towards the center. You could say it becomes solid but there would be no defining line. So Then differentiating between solid and fluid becomes a problem of where do you define the transition."
] | [
"So if you happened to magically stand on the 'surface', you would just sink into it until the density is enough to hold you up or crush you? That sounds terrifying."
] |
[
"To travel long distances around the Earth, would it be faster to launch into orbit and then re-enter at your destination rather than flying in an airplane?"
] | [
false
] | According to Wikipedia the fastest circumnavigation in an airplane is around 57 hours, but orbit seems to take only around 100 minutes. So it would seem faster (of course disregarding costs and the viability of a sustainable aircraft capable of multiple re-entries). | [
"Yes, the term for this is suborbital flight. There are several proposals of commercializing it to transport passengers.",
"Just a small detail, this is slightly slower than launching into orbit, that's why it comes back without completing a whole circle and why it's called \"suborbital\"."
] | [
"Yes, it would be faster. Although you've chosen to disregard the costs, they explain why this isn't regularly done."
] | [
"To give you a more intuitive glance at your question, space essentially starts at 100km (atmosphere is effectively non-existent). The ISS orbits at 330km.",
"To orbit the earth at 100km is only 1.5% longer than travelling across the surface. However, once you are out of the atmosphere you can get away with trave... |
[
"how does a magnetic field works fundamentally?"
] | [
false
] | null | [
"And i understand than a magnetic field is just a fake field which indicates the magnetic force",
"Magnetic fields aren't any more or less \"fake\" than electric fields.",
"At a fundamental level, according to QED, electromagnetic interactions are interactions between charged particles and/or electromagnetic fi... | [
"Electric and magnetic fields alone ",
" both a thing. Neither one is \"more fundamental\" than the other."
] | [
"But then he said i need to use a transistor to improve the current, which makes no sense to me since the current draw would be determined by the load it demands?",
"What book are you using, and what is the exact quote, with the context?",
"Anyway i looked at \"QED\" on wikipedia and it says charged particles a... |
[
"Is the universe beyond what we can see unobservable because we don't have the technology to see that far, or because the light has not reached us yet?"
] | [
false
] | null | [
"The latter. Specifically, the \"observable universe\" refers to the portion of the universe from which light could have reached us in the amount of time that has passed since the Big Bang. Anything outside of that region is unobservable because no signal could have reached us so far."
] | [
"We know how fast the universe is expanding, and it is accelerating. Unfortunately that means that as time goes on, more and more of the distant galaxies will slip beyond the horizon. ",
"http://en.wikipedia.org/wiki/Metric_expansion_of_space"
] | [
"We know how fast the universe is expanding, and it is accelerating. Unfortunately that means that as time goes on, more and more of the distant galaxies will slip beyond the horizon. ",
"http://en.wikipedia.org/wiki/Metric_expansion_of_space"
] |
[
"Can a pathogen be non biological?"
] | [
false
] | Ok so my immunology professor said "pathogens are only micro organism and hypoxia or any non biological can't be a pathogen" But the other day my pathology prof said "anything that can cause harm to a cell is a pathogen" he also argued that the name itself validate what he said So i went and checked my text book and ... | [
"That actually what i thought at first, Thank you!"
] | [
"That actually what i thought at first, Thank you!"
] | [
"In all uses of \"pathogen\" I've come across, it's for something that can replicate itself. Bacteria, viruses, even prions can be pathogens. But a toxic substance like cyanide isn't.",
"If you know any counterexamples, I'm interested to hear.",
"Extending that sense, something non-biological origin that can re... |
[
"Are semiaquatic animals (such as amphibians, crocodilians, hippos, etc) able to see clearly both in and out of the water? If so, how?"
] | [
false
] | Wouldn’t it require changing the focal point inside the eye to compensate for the difference in refractive index of the two mediums or something something physics? | [
"I belive amphibians at least developed another eyelid for out of water that helps see out of water. Frogs for example, are far sighted out of water and near sighted in water. ",
"https://biology.stackexchange.com/questions/58056/can-frogs-see-clearly-under-and-above-water",
"I'm not too sure about alligators a... | [
"In seals, the pupil dilates underwater and contracts on land, because sunlight on land is much brighter than the dim light underwater. This also effects the focus of the eye: in dim light with pupils dilated, underwater images are in focus. In bright light with the pupil contracted, the pinhole effect helps coun... | [
"Great response! Thanks for the info and links!"
] |
[
"Perpetual decline while also producing energy?"
] | [
false
] | Hi ! So I'm not talking about perpetual motion here, but more of 'something that needs a push to get started, then lasts a significant amount of time on it's own'. Ideally it also produces energy. While not producing energy out of thin air, the system uses 'almost frictionless' movement to continue moving for a while. ... | [
"The act of capturing the energy slows down whatever it is you've set moving. It doesn't matter if you can somehow achieve 100% efficiency, removing energy from the system ",
". At best, anything based on this scheme is a glorified flywheel."
] | [
"If it was able to produce more energy than it took to get started, it would be able to start itself over again, and hence could be made into a perpetual motion machine. So while you say ",
"I'm not talking about perpetual motion here",
"Your question is actually addressed by exactly the same reasons perpetual... | [
"Not so much 'stored energy' as it is timed/repetitive bursts to keep the system going. Like the example with the hurricane balls... an initial blow gets them spinning quite fast and for a long time. Don't the spinning balls produce energy from their motion? So yes it took an initial burst (blowing air) to get them... |
[
"Could staring at fire harm my eyesight?"
] | [
false
] | For example, if I look directly at a candlelight for a long time, would it damage by eyesight? | [
"Almost certainly no. Visible light is not capable of damaging the human eye in any circumstances you are likely to encounter. Candles and campfires do not put out significant UV (or higher energy) radiation, and it's really almost always the UV that causes eye damage.",
"Take an experiment that I performed years... | [
"I think that depends on how close you are to the flame"
] | [
"If you're too close you'll get burn damages!"
] |
[
"Has anyone tried to figure out where our solar system came from, and which other nearby solar systems originated from the same supernova?"
] | [
false
] | So, in the scale of billions of years, is it even possible yet to figure out which larger star or stars our system came from, and who are our brothers and sisters on the cosmic scale? | [
"Astronomers have been trying to answer this question for quite some time. They’ve surveyed millions of stars, looking for any that are the same age and have roughly the same composition as our sun, and they have found a few likely candidates. But there is a major issue, and it lies in trying to trace these stars b... | [
"Stars move with typical relative velocities of the order of 20 km/s. Over 5 billion light years this would correspond to more than the diameter of galaxy. In other words: This relative velocity makes the stars spread out all over the galaxy within 5 billion years. That makes finding \"siblings\" very hard."
] | [
"When astronomers do find a star that fits the bill, they have to run simulations backward on its orbit around the Milky Way, and hope that it’s in roughly the same place as our sun 4.65 billion years ago.",
"Wow... That sounds crazy to me. Can someone explain further? ",
"Over those distances and time scales, ... |
[
"Is this a meteorite? (Here are pictures and surface x-ray results)"
] | [
false
] | Hello everyone, A few years ago, I came in to the possession of this rock. I was told it was found in a farmer's field somewhere in Idaho. Recently, I was lucky enough to be able to use an x-ray gun to get a surface x-ray readout. The rock is slightly smaller than a basketball. I believe it weighs 225 ounces. It is ver... | [
"Treat the results of the hand held XRF (X-ray fluorescence analyser)with some caution. They are normally configured to analyse metal alloys and will not detect light elements such as silicon. They can be configured to detect light elements, and you would need to verify if this was the case for these measurements... | [
"Thank you very much for you detailed answer!",
"My biggest concern is the weight too. If it is indeed porous, then I fear it isn't from space. I believe at impact, a porous object of this size would explode. If it's not from space, given it's composition, I think it would have to be man made. A friend of mine th... | [
"Thank you very much for you detailed answer!",
"My biggest concern is the weight too. If it is indeed porous, then I fear it isn't from space. I believe at impact, a porous object of this size would explode. If it's not from space, given it's composition, I think it would have to be man made. A friend of mine th... |
[
"Can a dormant herpes virus become active if someone is in contact with cold sores?"
] | [
false
] | null | [
"Antibodies to HSV-1 in a person who is latently infected will prevent another primary infection by HSV-1.",
"However, other herpesviruses (such as EBV) can cause superinfections (a second primary infection) by evading the host immune response. See: ",
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC155020/",
"... | [
"I have type 2 and know a little...if you already have type 1 ( cold sores) but never show symptoms you should be immune to catching it(type 1) from someone and/or showing symptoms because of that contact...you should know that type 1 can be transferred to genitals if showing symptoms and type 2 CAN be transferred ... | [
"I was saying it is unlikely to transfer type 1(oral) herpes to the genitals or to transfer type 2(genital)herpes to the mouth. The types (1 and 2) typically stay in their \"preferred\" location. type 1 is oral and type 2 is genital. it's unlikely to transfer...But it can happen"
] |
[
"Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! ... | [
"Yes, it is! It is a larger scale effect of the Bergeron Process (",
"http://glossary.ametsoc.org/wiki/Bergeron-findeisen_process",
"). Essentially what is happening is that a few small ice crystals in the area have accumulated more ice via vapor deposition (cloud droplets deposit directly onto the ice surface)... | [
"maybe a ",
"Fallstreak Hole",
"?"
] | [
"The Hubble Deep Field observation covers an area of 2.3 x 2 arc minutes. This is a very small area (",
"See this image for scale",
")",
"The total exposure time was almost 141 hours or 5.8 days combined over several filters. To observe the whole sky with similar exposure times would require ~400,000 years of... |
[
"Are we born with bacteria in the gut? If so, at what point of time in mother's womb do we get that?"
] | [
false
] | null | [
"Where do gut bacteria come from?",
"These bacteria are placed in our guts mostly during and just after birth, coming from the mother, the immediate environment and the child's initial feed. Soon after this period, however, their make-up starts changing a little.",
"For instance, the mode of birth can make a di... | [
"Research into human microbiota is relatively new and just starting to get the traction it deserves. It was previously thought that newborns acquire their microbiomes at birth going through the mother's vaginal canal as the accepted notion was that the uterus was sterile, much like how urine was thought to be steri... | [
"Actually a lot earlier than we think. A lot of the colonization happens during birth and passage through the vaginal canal, but earlier than that, the fetus can swallow amniotic fluid which can begin to colonize the gut, though its not as influential as the changes that happen at or soon after birth.",
"And of c... |
[
"Regarding post in TIL about the sun being in its 18-20th orbit around the milky way, but only having completed 1/1250th of this orbit since the dawn of mankind. Could section/s of the orbit change conditions in our solar system in a drastic way?"
] | [
false
] | null | [
"In addition to the orbit around the galaxy, it also oscillates vertically within the disk. ",
"Some have theorized",
" that there are more cosmic rays around the \"front\" face of the galaxy, potentially affecting Earth.",
"This theory has yet to find general acceptance."
] | [
"The galactic arms are regions of higher star density in the galaxy. This \"density wave\" rotates around the center of the galaxy with a speed which can be somewhat different from the speed with which stars actually rotate around the same point. ",
"There's a region called co-rotation radius, where the rotation ... | [
"No, at least not by sections in the disk component. This is because the orbit speed is constant throughout the rotating disk due to the presence of dark matter. However, there are stars in the galactic halo that move on elliptical orbits and occasionally pass through the disk of our galaxy. It would be possible fo... |
[
"Does the drinking of acid fluids (such as coke) affect how much energy I can absorb from food?"
] | [
false
] | In other words, can acids break things into pieces that our body can't make use of anymore? For example, if I ate a burger while drinking coke, do I get less energy out of the burger compared to when I don't have a coke with it? | [
"No, it just adds more calories to your meal. The cola isn't actually acidic enough to have much of an effect. Your stomach is much more acidic due to hydrochloric acid, and contrary to popular belief, it doesn't break protein down into amino acids. It denatures them, meaning it makes them lose their shape so they ... | [
"Well, since the environment of the stomach is way more acidic than the soda, no. Edit to clarify: the acidity of the soda, which is what OP asked about, should have no appreciable effect on gut flora. The composition of our diets is influenced by what we ingest, and that influences how we absorb nutrients, but sci... | [
"But could it affect (over time at least) the gut biome which in turn affect bioavailability of nutrients?"
] |
[
"The fastest spinning neutron star spins at 716 times a second. How much of the immense gravity would be counteracted by the centrifugal force? How many times earths gravity would an object on the surface experience?"
] | [
false
] | [deleted] | [
"Just doing an order of magnitude calculation here: if a neutron star 1.4 times the mass of the sun is 10 km in radius and spinning 716 times per second, the gravitational field is 1.8 trillion m/s/s whereas the centrifugal force is about 10% that, at 200 billion m/s/s. This is an approximation of course."
] | [
"You know those videos where kids go superfast on a playground carousel and get thrown off?",
" Same principle, except instead of a carousel it's a neutron star. And instead of people holding on getting flung off, it's neutron star matter. And instead of the people being held on by their arms, it's gravity. "
] | [
"This is about right. NSs have considerable equatorial bulges from rotation. With a first order approximation of setting the surface gravity of a spherical mass equal to the centripetal acceleration you can find the Keplerian breakup frequency quite easily - for a 12km 1.4 solar mass NS it's about 4100 Hz, ",
"or... |
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