title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Is it possible for sperm to break through the walls of non-egg cells?"
] | [
false
] | I doubt the shape and motion of sperm is enough to puncture a regular cell wall, but what about the enzymes? If I remember correctly, sperm have an enzyme that helps it work through an egg's barrier. Could that or any other mechanism allow a super-potent and super-confused sperm enter one of the body's other cells? If possible, what would the effect be? I assume it would just spill the cell's contents. Might the hole it creates instead seal itself? How severely would the victim cell's normal function be impaired? | [
"No, it could not. Digestive enzymes from the sperm's ",
"acrosome",
" are not super-enzymes capable of digesting anything. They are only capable of digesting the very special (and very digestable) glycoprotein membrane of the egg cell, called the ",
"Zona pellucida",
"."
] | [
"In fact, the egg plays a much more active role in fertilization than is usually depicted - it kind of grabs on and reaches out for the sperm."
] | [
"You would also have to induce the ",
"acrosome reaction",
" in the first place."
] |
[
"Does the Earth's atmosphere rotate at the same speed as the planet?"
] | [
false
] | Does the atmosphere around the Earth 'turn' in sync with planet? So does The North Pole or England or anywhere else always have the same atmosphere 'above' it? | [
"The atmosphere \"slips\" relative to the surface of the Earth. There is a \"boundary layer\" where there atmosphere meets the surface of the Earths that creates all sorts of atmospheric phenomena (turbulence, uplift, jet stream, ...).",
"There are also large scale currents in the atmosphere: the Hadley cells.",
... | [
"So does the earth's crust rotate at the same speed as the underlying magma? How about the core?"
] | [
"There must be some amount of differential rotation going on, but that is on a much longer timescale. Differential rotation is needed (AFAIK) to drive the magnetic dynamo in the core."
] |
[
"On the anatomy and physiology level what does stretching actually do?"
] | [
false
] | As in, does stretching pre-flood chemical gates or lower the threshhold of said gates so that it takes less time/effort to move said muscles? And how does it actually reduce cramping later or have people just convinced themselves that it's true? | [
"Quick physio lesson time: The force producing units of muscles are called sarcomeres, and they work somewhat like a ratcheting mechanism where closely interdigitated protein filaments (actin and myosin) form chemical crossbridges that promote relative sliding of the myosin and actin chains. As a result, the amount... | [
"Yes this is all true, but the act of stretching has to do with ",
" length changes, whereas the LT curve you reference above (your husband) is active (as in, actively creating force with muscles). ",
"Passive length-tension has to with ",
"titin",
" at the sarcomere level, but mostly with extracellular tis... | [
"That same golgi tendon inactivation is why you don't static stretch before an exercise, you do a dynamic stretch, a warm up. A static stretch causes the golgi inhibition which temporarily creates that new set point for a \"stretch\", much closer to the injury threshold. So if you stretch the ankle before running, ... |
[
"I fill the bottom of a bottle cap with my blood and let it dry overnight. Then I put the dried disc in a cup of water. the color leaves the disc and seeps into the water. I'm left with a translucent, slimy material. What is it?"
] | [
false
] | [deleted] | [
"It's fibrin mesh, made from fibrinogen and the end result of the clotting cascade. It's a protein that polymerizes to form a hemostatic plug to stop bleeding and allow wound healing. "
] | [
"There seems to be a little confusion/questioning about what you're left with after the water step, fibrinogen or albumin so I looked up the blood contents",
"Conveniently there is this image at wikipedia, which is pretty fascinating:",
"https://upload.wikimedia.org/wikipedia/commons/c/cb/Blood_values_sorted_by... | [
"It's not very different from a scab, both are made of fibrin and other detritus, but a scab is dehydrated and so it's more brittle."
] |
[
"Why does a space shuttle arch as it leaves earth?"
] | [
false
] | null | [
"In order to orbit the earth, you need massive amounts of \"sideways\" velocity; just going straight up means that you'll fall straight back down when the rockets finish firing.",
"So the shuttle needs initial vertical lift just to get off the ground, and then gradually shifts to horizontal acceleration in order... | [
"Nice.",
"It's worth expanding this a bit: the only reason for the shuttle to go ",
" at all is to get above the atmosphere, to prevent drag. The reason it has to do that is because it needs ",
" lateral speed to be in orbit. Only a tiny fraction of the rocket fuel is used for going up -- essentially all... | [
"So stupendous, in fact, that if you look at the altitude data for the shuttle's climb to orbit, it actually begins falling back to earth about 2/3 of the way up to gain velocity.",
"http://www.spaceflightnow.com/shuttle/sts124/fdf/124ascentdata.html",
"At T+5:37, it begins losing altitude, having peaked at 356... |
[
"What technological advancement would make Thermoelectric Cooling a realistic substitute for conventional refrigeration systems?"
] | [
false
] | null | [
"One of the major issues facing thermoelectric cooling (via the Peltier effect) is the low efficiency and inability to handle large heat flux. The theoretical maximun rate at which heat can be carried away by a Peltier device is determined by the Peltier coefficient (property of the materials used) and the current ... | [
"Thanks for the elaborative answer. I hope researchers keep looking for that magic material.I worked on two projects in school, one where we tried to cool an enclosed space using 8 Peltier modules with huge heat sinks attached to the hot side, and it was good enough to produce the cooling effect quickly, but reache... | [
"it's a physics and materials problem, not a problem of making things tiny like computing.",
"that said, a crutch solution is faster heat transfer away from the hot side (better heatsinks) but that's only one third of the solution."
] |
[
"How do phones keep cool with small heatsinks and no fans?"
] | [
false
] | [deleted] | [
"They have a lot of surface area and they throttle their performance if they are too hot. This is a major constraint for mobile VR, phones have a lot of computing power but they can't use it at 100% for extended periods due to heat."
] | [
"Also it should be noted that most phone chips are very low wattage. The snapdragon 835 (A very powerful mobal chip) only pulls about 3.5 watts. most intel/AMD X64 chips pull 65 watts With the very high end ones pull over 200"
] | [
"It may depend on the material, but in general yes. Most cases have a rubber interior to prevent damage to the face, which would act as a thermal insulator and reduce the amount of heat the phone can transfer to the environment. A metal case may, in theory, slightly improve the heat transfer of the phone by offerin... |
[
"What is the difference between saturated, unsaturated, and trans fats, and how does it affect our health?"
] | [
false
] | I know c.10 years ago every "medical expert" and their mother was touting the cholesterol-lowering benefits of unsaturated fats, particularly the all-holy "omega-3 fatty acids," but I've since heard quite a few different testimonies saying otherwise, from 's "saturated fat is fine as long as you get it from the half-dozen eggs you eat every day" to the and lowered his LDL cholesterol 20% in 10 weeks. My only direct concern with this is whether my parents are really better off taking "fish oil" pills to help lower their LDL levels (which haven't changed much since they started taking the pills a year and a half ago), but I'd also like to know the current medical consensus on different fats' health effects as a whole. | [
"The health effects of different fatty acid classes are always under debate. IMO there is little consensus in the field, if by consensus you mean something everybody agrees about.",
"It's a personal interest of mine (I'm just a dilettante), so I can give you a very brief overview of the subject. I can provide ref... | [
"Saturated fats have only single-bonds between carbon atoms (the molecule is saturated with hydrogen atoms).",
"Unsaturated fats contain at least one double-bond between carbon atoms (the molecule is not saturated with hydrogen atoms).",
"Trans-fats are a specific type of unsaturated fats that contain only \"tr... | [
"Thus, saturated fats and trans-fats are more difficult for the body to\nbreak down into simpler molecules and to utilize the energy from the\nbonds of these fats.",
"I don't think that's true for saturated fats. Mitochondria are quite happy to burn saturated fats, and in fact high-saturated fat diets are therape... |
[
"What happened to my defined jawline?"
] | [
false
] | null | [
"Hi Double_Joseph thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the f... | [
"Human body"
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"For more information regarding this and similar issues, please see our ",
"guidelines.",
"If you disagree with this decision, please send a ",
"message to the moderators."
] |
[
"Are there materials that only emit Alpha radiation? My Geiger counter only detects beta and gamma."
] | [
false
] | null | [
"Pure alpha sources exist, but you don't need one to discriminate between alpha counts and beta/gamma counts in the detector. Given the very short range of alpha particles in matter, you'll only be able to detect alpha particles when the detector is held very close to the source.",
"So if you hold the detector cl... | [
"So you're saying that my Geiger counter claims to only detect beta and gamma rays, but it can actually detect alpha rays also? But that's because alpha rays don't travel very far, so it doesn't claim to detect the alpha radiation?"
] | [
"So you're saying that my Geiger counter claims to only detect beta and gamma rays, but it can actually detect alpha rays also?",
"No, I'm assuming you're using a model which has a thin enough window to detect alphas, or everything above is irrelevant.",
"But that's because alpha rays don't travel very far, so ... |
[
"Why in arthropod species where females are larger than males and sometimes consume potential mates, do the males not grow larger to evade this threat?"
] | [
false
] | null | [
"I think another way of looking at it is this: is it really a net positive for the species as a whole for the male to evade being consumed? Let's try to think about it from a perspective that isn't anthropocentric.",
"Consider: if the male did his job in the reproductive act, what other purpose does the male serv... | [
"Or that the evolutionary advantage is actually in favor of the male who does not evade, because it helps the female in the species more. Or even that it's more selective, in that the female will only mate with males who are small, the larger ones don't get the chance to reproduce."
] | [
"If males and females eat the same food, and it is in short supply, then the male may actually be doing his genes a favour by dying off, so that his girlfriend can eat better and raise some strong, healthy kids. In the short term, anyway -- which is the term that natural selection sees."
] |
[
"Does the Dzhanibekov Effect occur with throwing knives?"
] | [
false
] | null | [
"If it has three different principal moments of inertia, yes. But rotations around the principal axes with largest and smallest moments are stable."
] | [
"Doesn't any macroscopic object have three different principal moments of inertia?"
] | [
"No. If the object is symmetric, two or more of its principal moments may be equal in value."
] |
[
"psychologically speaking, why do we sometimes laugh when presented with sad or unfunny things?"
] | [
false
] | For example, "shock jokes" are meant to make you laugh by saying something you wouldn't expect. Also, that video of the boat spinning around the whirlpool during the Japan tsunami made me laugh, even though there shouldn't be anything funny about that. Do we laugh because we don't know what else to do, because we are trying to cope, or is it something else? EDIT: I probably should have started out by asking "why do we laugh?" I thought laughter was a purely human act in response to something funny, but it seems more complicated than that. | [
"These quotes are all very nice, but I was hoping for something a little more substantive."
] | [
"Radiolab, Laughter"
] | [
"\"It's annoying when people answer difficult questions with well known aphorisms.\" -- Me"
] |
[
"Is it actually healthier to go braless?"
] | [
false
] | null | [
"In other contexts, guys making studies on bouncing boobs would be frowned on.",
"What are you trying to insinuate here? It's one thing citing the author saying that the study might not be representative. It's another inserting your own insinuations into the study.",
"If the movement of the breasts is necessary... | [
"In other contexts, guys making studies on bouncing boobs would be frowned on.",
"What are you trying to insinuate here? It's one thing citing the author saying that the study might not be representative. It's another inserting your own insinuations into the study.",
"If the movement of the breasts is necessary... | [
"A comprehensive analysis would not necessarily lead to different results. I think the issue here is one of data collection. The benefits cited are purely cosmetic. No health claims are made, other than anecdotal self-reported evidence of less back pain.",
"So, to answer your question in the most scientific way p... |
[
"Are there stars that do not emit light on the visible spectrum?"
] | [
false
] | Are there stars that we cannot see with are make eye? If so, how did we find them and how are we able to tell? | [
"There are stars that are too cold to emit visible light and emit mainly infrared radiation instead. These are called brown dwarves, and are kind of on the edge of what we'd classify as stars because they don't have hydrogen fusion in their core (some have deuterium fusion though). These can be detected with infrar... | [
"Short answer, No",
"Longer answer, depends on what you call a star. Brown Dwarfs emit mostly infrared light. Depending on who you ask, they’re not really stars though because they don’t sustain fusion. For any “real” star, they would emit visible light. This is because stars emit what’s called Blackbody Radiatio... | [
"There are also stars that emit visible light but are just too faint to see with the naked eye.",
"99.999999999...% of the stars in the observable universe are in that category. We see a few thousands out of 10",
" or so. That just means they are too far away. If Proxima Centauri would be closer we would see it... |
[
"Did dinosaurs evolve into birds because flight became necessary?"
] | [
false
] | It seems to be accepted that dinosaurs evolved into modern day birds. Most birds can fly. Most dinosaurs could not. What was the mechanism by which birds were selected to fly when their predecessors could not? | [
"Nope. The evolution of flight and the evolution of birds are very much decoupled from each other; flight occurred in non-avian dinosaurs as well.",
"There are a few characters we strongly associate with flight: feathers, hollow bones, and a ",
"unidirectional airflow system in the lungs",
" that makes respir... | [
"The statement \"dinosaurs evolved into birds\" is very misleading. It's kind of like saying \"mammals evolved into whales\". ",
"It's better to think of it this way. Birds ",
" dinosaurs. They are the one group of dinosaurs that survived the KT extinction event. All the dinosaurs you know of (T-Rex etc.) ... | [
"There's no proportional difference between flying dinosaurs and birds. Birds ",
" flying dinosaurs. If you're asking why most birds fly and most extinct dinosaurs did not, it's because all birds today are descendents of a group of flying dinosaurs. Flightless birds are secondarily flightless. Flight was not the ... |
[
"What is an explanation for the rapid increase of Autism Diagnosis in the past few decades?"
] | [
false
] | Can it be attributed due to innovations of technology that allow us to accurately diagnosis cases, in which may not have been diagnosed in the past due to limitations on technology or just plain out factors that we still have yet to fully grasp - environmental, genetic defects, etc. ? | [
"There was a big increase in the recognition of autism after Rainman came out in 1988. Before then autism was hardly known outside a the circle of a few notable pioneer researchers and parent groups e.g. The national autistic society in the UK. For example, in the 1970s it was thought that autism was a rare conditi... | [
"This is very nice explanation of the most important reasons why autism diagnoses seem to be going up. It's also summed up in ",
"this article in Nature",
". ",
"In short, we can explain about half of the increase we are seeing. Apart from better recognition and awareness of autism by both clinicians and pare... | [
"That's a good article, very interesting. I met one of the people mentioned in the paper, Terry Brugha. I'm inclined to think that Terry's idea that autism a has always been the same is more likely than a partial real increase; he supported this idea with a door to door survey that found a similar incidence of auti... |
[
"Can anyone help me understand why my post is being taken down??"
] | [
false
] | null | [
"All posts are placed in a mod queue and released manually. Please read the posting guidelines."
] | [
"it was a question on replication of virus. I dont know how it violates any guidelines"
] | [
"It is likely still in the queue waiting for a mod with the relevant background to review it."
] |
[
"Is there any non graphic proof that when n appoaches infinity, |(x^n)| + |(y^n)| = r is a square?"
] | [
false
] | I've been playing with online cartesian drawing tools. When n=1, it is a rotated square at half PI. Then it will transform into a circle while rising n slowly towards 2. Then, an interesting thing began. Any increase in n will make it more square-y but will never become a complete square. Will it became a true square when n reaches infinity? What is the proof? | [
"Let's use r=1. You can ask for which x,y does |x",
"| + |y",
"| converge to 1. Let's say x,y>0, r=1 and x=cy for 0<c<1, the other cases can be treated using symmetry or they are trivial. Then |x^(n)| + |y^(n)| = y^n (1+c^(n)). For y<1 this converges to zero, for y>1 this diverges, for y=1 this converges to 1."... | [
"For any point (x',y') where |x'|<1 and |y'|<1, you can show that that point lies inside the |x",
"|+|y",
"|=1 curve for all sufficiently large n. ",
"Basically you show that for any fixed 0<k<1, k^(n)-->0 as n-->infinity, and apply that to both x' and y'. ",
"Is \"every point in the interior of the [0,1]",... | [
"The function f(x,y) = (|x^n| + |y^n|) ^ (1/n) is often called L_n, or the n-norm.",
"For n=2, L_2 is the usual Euclidean distance from the origin to point(x,y)",
"For n=1, L_1 is the Manhattan distance, that is, if you have to travel from the origin to point (x,y) but you can only walk alongside the \"grid lin... |
[
"Weight of potential energy?"
] | [
false
] | The energy put into compressing a spring, does it have measurable weight (no matter how miniscule, theoretical question)? | [
"Note that in practical situations, this weight increase is so small that you would not notice it on a scale."
] | [
"Note that in practical situations, this weight increase is so small that you would not notice it on a scale."
] | [
"So, i'm not actually sure about this. Maybe it's true for a spring - for mechanical potential energy - but is it true for gravitational potential energy? I think not, right?",
"And in the case of the spring - where precisely is that additional mass stored?",
"Does this also imply that the mechanical stresses... |
[
"Do the holes on a dice which represent the numbers affect the chances of getting different numbers?"
] | [
false
] | null | [
"Yes they do!",
"If you look at the regular dice you get from, say, a Monopoly game, you'll find many things that can change the chance of rolling a specific number.",
"First your question: The mass on the 1 side (with one hole) is higher than from the opposite, the 6 side (with six holes), so the 1 side is the... | [
"I can't speak to the physics, but I can tell you that dice used in gaming license venues adhere to pretty strict balance properties, and are constructed with this in mind. No single set of dice is ever used for too long for the same reason.",
"Cheap dice do not adhere to these rules, and are often unbalanced, so... | [
"Dice used in gambling do have their pips (the names for those holes) filled in, negating whatever small influence they might provide, but the real factor that makes them expensive is that they are machined to a certain tolerance where cheaper dice are injection (edit: or compression) molded and then polished to ta... |
[
"If one identical twin gets a cancer of the blood, and they share blood with the other twin, do they 'catch' the cancer?"
] | [
false
] | null | [
"Completely and utterly wrong.",
"'blood cancer' is actually reliant on bone marrow to produce the cells which cause the cancer. This is reliant on a number of things and simply sharing blood is not going to mean you 'catch' cancer. "
] | [
"You made a few errors, I'm afraid"
] | [
"Quite right on both counts, my mistake.",
"In my defence it's 5:45 in the UK and I have yet to go to bed.\nI meant to say metastatic instead of malignant."
] |
[
"Does every object that has mass have a Schwarzschild radius, even sub-atomic particles/fundamental particles?"
] | [
false
] | null | [
"Yes, it's just a function of mass.",
"Massless particles do not."
] | [
"The issue is that you can't Lorentz-transform to a frame where they're at rest. There is a gravitational field for a massless particle, which agrees with the limit of an extremely Lorentz-transformed Schwarzschild solution.",
"The paper on this claims \"On this plane the Riemann tensor has a δ-like singularity a... | [
"Wikipedia says that, but Wikipedia is not necessarily right. In fact, most things on Wikipedia about Planck units are wrong. That page also states that nothing can be localized to smaller than its Compton wavelength, but the radius of the electron is known to be more than 10 orders of magnitude smaller than that."... |
[
"How did chemists first calculate bond angles?"
] | [
false
] | Was it based off of the molecular structure? | [
"Bond angles were first measured by analyzing the infrared spectra of a molecule to determine at which frequency the bond vibrations resonate with the frequency absorbed by said IR light. With this information, you could assume that the bonds act like springs and the atoms as weights and determine the angles of the... | [
"/u/alexryan94",
" is correct in saying that the first bond angle measurements were based off vibrational absorptions seen in IR spectroscopy. However, this method is not particularly robust and is considerably more difficult to apply to larger structures.",
"Röntgen won the Nobel Prize in 1901 for discovering... | [
"XRD has been used to determine molecular structure with precision for quite a while now, so I'm not sure what you mean."
] |
[
"How does supersymmetry solve the hierarchy problem?"
] | [
false
] | Hoping for an explanation that doesn't require me to learn too much extra notation. I understand the basics of supersymmetry, and I understand the "fine-tuning" problem that exists without it, but it seems like the claim that it solves the hierarchy problem is passed over without much attention, or it involves crazy math. I realize that this question may involve too much math in order to be explained on this site. Thanks in advance. | [
"The solution rests on the non-renormalization properties of supersymmetry, which cause quadratic divergences in loop diagrams to cancel out. Naively, the Higgs mass (which we expect to be around the weak breaking scale, and which perhaps is around 125 GeV) would receive quantum corrections proportional to the squ... | [
"To expand on this, fermions and bosons contribute to the Higgs self energy with opposite signs. In supersymmetry, the fermions and bosons in SM have partners with opposite spin which makes δm",
" almost zero (not Λ",
" )."
] | [
"You have to look at the diagrams that contribute to the renormalization of the Higgs mass. The coupling between Higgs and two fermions can produce a H->H diagrams in which you have fermions running in the loop. The quartic coupling of 2 Higgs + 2 bosons give you another loop diagram with the bosons running inside.... |
[
"Why is the human body homeostatic at ≈36.8°C?"
] | [
false
] | I know it's bad for sperm production. Is this a good temperature for certain chemical reactions? Is it in response to climate? Why not 30°C? Or 40°C? | [
"Well, first of all your body temperature does fluctuate throughout the day and can be different depending on the person, time, where you measure, etc.",
"That said, there is a general set point that does indeed exist that probably arose out of evolution. The really famous study that you'll probably encounter is ... | [
"While I agree with what you'd said it's also extremely important for you to note what InbredScorpion had added. That is, that the protein action inside our bodies is most efficient at this temperature. They work most rapidly, without the risk (most) of denaturation at this temperature."
] | [
"I am not sure if this is an inherit reason as to why the body is homoeostatic at 36 - 37°C but... proteins work optimally at around 37°C. Increasing or decreasing the temperature too much (not in the case of spermatozoa, which sits around 33°C) will cause the proteins to denature.",
" "
] |
[
"Suppose two people with different copy number variations(CNVs) mate . . ."
] | [
false
] | Say guy has 5 copies of a gene (homologous) and girl has 7 copies (homo.) What will child have? I ask this in the context of autism, which seems to be related to CNVs in at least some cases. | [
"If we're talking about the same gene, then think about it this way:",
"It depends how many copies are on each chromosome. If the guy has 4 copies on one homolog and 1 copy on the other homolog, the child can either inherit either the chromosome that has 1 copy or the chromosome that has 4 copies. Same with the... | [
"Yep!"
] | [
"That rather depends on which chromosomes they're on and how many on each. genes/sequences that are on the same chromosome tend to violate mendelian genetics rules of thumb because the closer two sequences are to one another, the more likely it is that they'll be inherited as a group rather than independently. If... |
[
"How are electrons shared in compounds?"
] | [
false
] | Since electrons orbit the atomic nucleus how can an electron be shared between two nucleus? Does it do a figure of eight between them and is it always the same electron that is shared? | [
"The electron ",
" is delocalized from the atom. There is still charge neutrality since there is the same number of positive and negative charges, but the electrons are no longer electromagnetically confined to a single atom. Don't think of them as individual particles orbiting, but a probability cloud that is sp... | [
"Different atomic electron shells have different shapes arising from the probability of the electron to be found in different places. When we talk about books between now than one atom we consider the electron orbital of the atoms to be overlapping, in effect the electron is now free to move about both atoms in thi... | [
"Electrons of atoms don't really follow Newtonian mechanics, they follow quantum mechanics. So when they are shared, they're shared by probabilities rather than by orbits.",
"Quantum mechanics was an unexpected solution to the problem of the electron spiraling into the nucleus, and also the so-called ",
"ultrav... |
[
"How is it that our visible light spectrum can be displayed via a ciclic representation (the color wheel) when the light spectrum is linear?"
] | [
false
] | The 'break' would be between red and blue, I assume. But it is able to seamlessly circle back through purple. I'm curious as to how that fits in with the linear representation of visible and non visible wavelengths of light. On that note, what would a color wheel look like if it integrated non visible light? | [
"The color wheel is based on what people see rather than the whole spectrum. It would be better to think of it less as a wheel and more of a triangle. And even better to think of it as ",
"this weird shape",
". There very much is a break between red and blue.",
"For each additional frequency of light you inte... | [
"Interesting addition to that weird shape.(which in itself is a cross section of a 3d shape, iirc the hidden dimension relates to brightness) that edge there that is marked with numbers from 460 to 620, those are pure wavelengths in the spectrum and their positions in the graph correspond to those colours. Colours ... | [
"The main reason why we represent the colors as a wheel or some other two-dimensional graphic is that we have three different color sensing cells in our eyes, the ",
"cone cells",
".",
"Any of the colors on the \"color wheels\" only represent the ratio of the three colors we perceive - if you look at the pict... |
[
"AskScience AMA Series: We are building the national quantum network. Ask Us Anything about the #QuantumBlueprint"
] | [
false
] | Last Thursday the to build a national quantum internet. This #QuantumBlueprint is meant to accelerate the United States to the forefront of the global quantum race and usher in a new era of communications. In February of this year, DOE National Laboratories, universities, and industry experts met to develop the blueprint strategy, laying out the essential research to be accomplished, describing the engineering and design barriers, and setting near-term goals. DOE's 17 National Laboratories, including Argonne National Laboratory and Fermilab will serve as the backbone of the coming quantum internet, which will rely on the laws of quantum mechanics to control and transmit information more securely than ever before. The quantum internet could become a secure communications network and have a profound impact on areas critical to science, industry and national security. (Fermilab Scientific Computing Division) and (Argonne National Lab's Center for Molecular Engineering) will be answering questions about Quantum Computing and the Quantum Internet Today at 2 PM CST (3 PM ET, 19 UT). AUA! Usernames: ChicagoQuantum | [
"My understanding is Quantum computing is done at very low temperatures - is this required for a quantum internet and how can this be achieved over distance?"
] | [
"A: Not necessarily. Some quantum processors may need to operate at very low temperatures. But the quantum internet is designed to transmit quantum states to different places. Scientists typically use photons as the vehicles to transmit quantum states. Photons are transmitted either in telecom fibers or in free spa... | [
"It's my understanding that creating the entangled particles is hard to do. How will you handle the extremely large amount of connections being made?"
] |
[
"Can our bodies tolerate environments without oxygen?"
] | [
false
] | What I mean is, if we have access to a normal breathing atmosphere through some sort of breathing apparatus, would our bodies otherwise tolerate being in an atmosphere (same pressure as normal) devoid of oxygen? The only answers I was able to produce while searching related to what happens to our bodies in space or on different planets, and that our skin doesn't "breathe", but still absorbs oxygen. So just as an extreme example, if we were to find another planet with the same pressure and composition as ours but lacking oxygen, or if our own somehow ran out of oxygen, would there be a limit to how long we could stay outside without a suit, aside from the oxygen required to breathe? Or in other words, what would happen to our bodies if the respiratory system was the only part of us that had access to oxygen (most of the time)? (not sure if right tag) | [
"As long as your body intakes normal air, and the atmosphere outside is the same pressure as our atmosphere, then I would think that nothing of significance would happen. Being submerged in water and having a breathing apparatus, but not a full diving suit is possible already, so long as the pressure differential i... | [
"Yup, for anyone interested, many SCUBA divers use wetsuits which trap a layer of water inside that your body heats up to keep you warm even in somewhat cold waters. Drysuits keep the water out but are less comfy and are for more extreme cold temps, usually < 50°F (you get cold faster in water so even 50° is danger... | [
"Yes, when doing gas work we have to enter low oxygen areas with a breathing apparatus of course. The low oxygen doesn't affect your body. However without the breathing apparatus and no suitable oxygen to breath then your body will not be triggered to expel carbon dioxide and you will just not be able to breath at ... |
[
"Why do the variables in cosmological equations have the values that they do?"
] | [
false
] | [deleted] | [
"Really, nobody knows why the universe has the properties it does. Gravity could be arbitrarily stronger without \"logical\" contradiction but we live in a universe where it has the strength that it does.",
"The cosmological constant, before it was measured, was derived from quantum electrodynamics. Then it was ... | [
"Because it's off by 120 orders of magnitude."
] | [
"Because it's off by 120 orders of magnitude."
] |
[
"Was Venus ever within the habitable zone of our Sun?"
] | [
false
] | It is a known fact that main sequence stars increase their luminosity over time, as helium accumulates in their cores. Even though our own sun will be around for ~5 billion more years, it will have gotten bright enough 500 million years from now to have boiled away our oceans. So what if we turn back the clock? Was there a time, say, 3 billion years ago, when the current orbit of Venus would've been within the habitable zone? Would it have been in the habitable zone at the time (considering how chaotic the early solar system was, it's likely that all of the planets moved at least a little bit, IIRC)? Is it still within the habitable zone now? EDIT: Torn between "astronomy" and "planetary science" flairs. | [
"Venus is actually in the habitable zone, however its thick atmosphere prevents temperatures for life as we know it to exist. While studying astronomy, one of the things a professor pointed out was that if Mars and Venus were to be swapped, both would likely be able support life."
] | [
"This always is asked about Mars. I have read enough responses to feel like I can answer. Solar wind has stripped away the atmosphere on mars already. That’s why it’s so thin. But it took millions of years to do it. It’s because Mars doesn’t have a liquid rock and rotating iron core like Earth does and this means M... | [
"Wouldn't Mars's extremely thin atmosphere likely have been blasted away by solar wind if its orbit was swapped with Venus's?"
] |
[
"What is the chemical signaling process for memory in the brain?"
] | [
false
] | [deleted] | [
"Memory is an emergent property of several interacting signaling processes. It is thought to be encoded in the connectivity of neural networks, including signaling strength between neuron pairs. This process is guided by several different mechanisms, but the most general description of them is hebbian learning an... | [
"How does calmodulin relate to memory, mechanistically?"
] | [
"Calmodulin is all over, in multiple sites around cells. When associated with ion channels, it can prolong spiking in cells by holding those channels open, which can facilitate LTP. Calmodulin has also been shown to participate in transport of AMPA receptors that turn silent synapses into active ones. It probabl... |
[
"Two questions regarding the limiting power of the speed of light"
] | [
false
] | I realize that these questions resemble that of "troll physics" but I was curious anyway. If I were to have a unbreakable, massless stick of 1 light-minute in length, and I used that stick to poke somebody 1 light-minute away, would it take exactly 1 minute for them to feel it? If so, could somebody explain why? If I were to take that same stick, and move it in an arc over my head at, from my perspective, 90% the speed of light, how would the end of the stick behave? | [
"If you had a massless stick, it would have to be moving at the speed of light. All massless particles move at the speed of light.",
"But lets say you had a stick of 1 light-minute in length with mass. If you push one end of the stick, the pressure wave from the push would propagate at the speed of sound, not lig... | [
"when you push on your end, the atoms in the stick need to \"talk\" to their neighbors by pushing on them. And so on down the line. The fastest they can possibly communicate (push on each other) is at the speed of light. ",
"This is slightly more challenging to answer, you mean the end of the stick on your end is... | [
"It would take as long as it takes a sound wave to propagate through the stick, which is how fast the poke would travel. The fastest speed of sound I know of is about 20 km/s, but I think neutron stars might have interior speeds of sound approaching the speed of light.",
"It would follow an arc, with the tip tra... |
[
"After doing a repetitive task for hours on end, sometimes you close your eyes and you can see it. What is going on here?"
] | [
false
] | I'm talking about after those late nights of playing games, you close your eyes and see DotA 2 behind your eyelids. Or if you spend all day picking fruit, take a shower and close your eyes only to see apples everywhere. Anyone know what gives? | [
"The Tetris effect (also known as Tetris Syndrome) occurs when people devote sufficient time and attention to an activity that it begins to overshadow their thoughts, mental images, and dreams. It is named after the video game Tetris."
] | [
"Excellent. Thanks for the reply! Any idea how it actually works? Also, it would be interesting to learn if the hallucinatory nature of this phenomenon is caused by the same thing that causes ",
"GTP",
"."
] | [
"is this akin to \"highway hypnosis\", where, after a long stretch of highway driving, your internal 'speed sensors' are out-of-whack and higher-speeds feel slower than actual?"
] |
[
"If a person with a certain communicable disease dies of it and is buried, do the said pathogens continue to live, multiply and spread in the soil?"
] | [
false
] | By extension, like how vaccination improves herd health, shouldn't incineration be a preferred mode of disposal of the dead rather than burial? | [
"This will depend on the pathogen in question. Some examples:",
"Anthrax can survive in soil after the host is dead, although the bacteria aren't actively multiplying (instead, they form spores).",
"Prions can also persist in soil (\"survive\" is the wrong word here because they're not alive)."
] | [
"Mortuary worker here, embalming/sterilizing (which you can't really guarantee to be 100% sterile) isn't required for burial at all, and even for most diseases (Hep C, AIDS, MRSA etc.) it isn't required by the funeral home or the law (at least in Colorado, USA). There are some EXTREME cases such as Ebola where the ... | [
"If something can multiply in soil and infect humans at the same time then it is everywhere anyway."
] |
[
"If an object is dropped in a vacuum and pulled down toward Earth, changing its gravitational potential energy into kinetic energy, does it lose any of this energy as heat?"
] | [
false
] | The way I understand it is that every time energy changes form, some of the energy is lost as heat energy. However, in this situation, what would cause the production of heat without friction from air resistance? | [
"If it is a perfect vacuum then no, there would be no drag and thus no gravitational energy converted to heat. It will lose all of its kinetic energy to heat when it smacks into the edge of the vacuum vessel though...",
"Edit: Clarity"
] | [
"The source could have been anything. cpxh just means that any object with a temperature greater than 0K emits blackbody radiation, regardless of if it is caught in a gravity well. In an ideal system such as your example, the transfer of energy from potential to kinetic will be 100% efficient, so no lost energy w... | [
"The object would still be radiating heat to the walls of the vacuum, but thats not really what you were asking about. "
] |
[
"If we take all of the world's CO2 emissions and compressed it to a diamond, how big would it be?"
] | [
false
] | null | [
"The world emitted 36 gigatons of CO2 in 2014. A CO2 has a molecular mass of 44.01 g/mol, while carbon has a molecular mass of 12 g/mol, meaning that 27% of the weight of CO2 is carbon, meaning that that CO2 emission produces 9.8 gigatons of Carbon. If this was compressed into diamond it would still weight 9.8 bill... | [
"Love ",
"/u/NeuroBill",
" 's answer, but here's another way of looking at it: if you're an average American, your personal diamond weighs 4.5 tonnes, and measures about 4 feet by 4 feet by 3 feet. And you create a new one every year."
] | [
"This is also a really nice answer, I like this personal perspective."
] |
[
"Would it be possible to build a large double slit experiment to examine the behavior of gravitational waves? If so, would that be proof that gravitons exist?"
] | [
false
] | null | [
"No, even ignoring the technical challenges of building such a contraption, it couldn't be used to prove the existence of gravitons. The reason is that the double slit experiment is most directly related to the wave-like properties of a field. For example, the general properties of light as a wave, including things... | [
"And the technical challenges are pretty intense: you need to find a material that can block disruptions in spacetime - which also would be resistant to all of relativity, including gravity. "
] | [
"There are no opaque materials for gravatational waves, so there is nothing for them to diffract off of."
] |
[
"Why can we see objects millions of light years away?"
] | [
false
] | If I have this right, photons travel in a straight line. So, if you imagine a crude drawing of the sun, with sun beams coming off of it, the further these sun beams get from the center, the more spread out they become. Even if a star is giving of Billions upon billions of photons. wouldn't their distance to each other become so spread out that it seems unlikely that we should be able to detect them, let alone get a complete picture out of them? Am I just not comprehending how MANY photons are let off, that it does still spread, but not enough, even millions of light years away? Or is something else happening that lets us see such distant objects? | [
"It's crazy, but that's exactly right.",
"Let's think about the Sun for a moment - its luminosity is on the order of 10",
" watts. Half of that power (more or less) is in the visible spectrum, and a visible photon has the order of 10",
" J of energy. That means that the Sun emits on the order of 10",
")=10"... | [
"Because they're really big and bright. "
] | [
"Not quite. A long exposure is always useful in gathering more photons, but the age of the galaxy itself is irrelevant. The light that reaches us is millions of years old (for example, the light from the Andromeda galaxy is 2.5 million years old when it reaches us, as it is 2.5 million light years away). Howoever... |
[
"Is there any such thing as gravity wave interference?"
] | [
false
] | Could gravity waves from all of the sources in the universe interfere with each other destructively/constructively? Also, I was reading about effect created by colliding kinetic waves, and I wonder if colliding gravity waves could interact in a similar way to produce a repulsive effect, and could that effect be a contributor to the expansion of the Universe? These are questions founded on bodies of knowledge I don't possess, and for that I apologize--but I'm curious nonetheless. | [
"Like any other kind of wave, gravitational waves can certainly interfere with each other.",
"I don't know about the tractor beam thing specifically, but people have put forth the idea that gravitational waves are responsible for the accelerating expansion. The answer as I recall is that you can get a small effec... | [
"Bonus questions: is space expanding in all dimensions? Are any dimensions contracting? ",
"I'm told that ",
" is expanding like the skin of a balloon, and the galaxies, nebulae and other objects within are like dots drawn on the surface--but if \"space\" is expanding, where is the \"new space\" coming from? Th... | [
"Yep, space is expanding equally in all directions, at least as far as we can tell.",
"It's a matter of some debate among philosophers whether or not space is like a \"material,\" that is, whether or not all those questions you just asked make any sense. From a physical point of view, it doesn't matter too much. ... |
[
"What's the difference between a chelating agent and a surfactant?"
] | [
false
] | null | [
"A surfactant reduces surface tension, usually between water and air or oil. These surfactants have a hydrophilic end and a hydrophobic end. The hydrophilic end sticks into the water and the other end either faces the air, or sticks into the oil. If it's being used for oil on water, the surfactant molecules will su... | [
"I'm sure someone else will come along but in general:",
"Chelation is the sequestering of metal ions by a compound so it is not available to react with anything else. ",
"Surfactants lower the surface tension of a liquid. "
] | [
"Quick difference:",
"Chelators keep metals in solution real good.",
"Surfactants help oily stuff and watery stuff stay together in solution real good (in addition to the surface tension effect everyone else mentions).",
"Yes, I know that this is very hand-wavy but I'm trying to skip a bunch of technical stuf... |
[
"What would happen if it unexpectedly rained a lot in a desert?"
] | [
false
] | [deleted] | [
"This is actually how it works in some deserts. They don't have small amounts of rain for a while but huge bursts of rain. This can lead to flash floods (southern california, arizona, other areas). ",
"Part of the problem for deserts is the lack of rain, but also sand and \"large grains\" of soil don't really ret... | [
"The plants that do adapt to it, like saguaro cacti, can suck up a huge amount of water from a single storm. I don't remember which BBC doc it was that did this, but I remember seeing a time lapse shot of a cactus swelling with water from a storm. "
] | [
"something like this",
" perhaps ... \nI am not 100% sure if that is the type of desert the OP has in mind (i guess he means more of sand dunes and similar...)"
] |
[
"How is gravity \"weak\"? What scale are we using to compare the forces?"
] | [
false
] | I've heard the example of being able to counteract the gravity of the entire earth merely by picking something up, but that is a subjective description of weak. In what way can four forces be compared that makes us wonder why gravity is weak, and why would we expect them to be similar? In other words, why do we need an explanation as to its relative weakness? I hope this question makes sense... | [
"For example, if you consider the attraction between an electron and a proton, the electrostatic attraction is about 10",
" times as strong than the gravitational attraction."
] | [
"Randal Munro (author of XKCD) recently addressed that exact scenario in his feature ",
"Proton Earth, Electron Moon",
". The calculation works out that the repulsive force created by that many charges, so densely packed, would represent energy that itself would have gravity.",
"I highly recommend checking ou... | [
"The way I heard it explained is, imagine how large the earth is. Now imagine how all of it's gravity would be acting on a small 1cmx1cmx1cm iron cube. Now imagine how a small magnet could lift up this cube. A tiny magnet could cause more force on the cube than the earth. Im sure this is oversimplified and it's mor... |
[
"What exactly is spin in quantum mechanics?"
] | [
false
] | None of the explanations get traction in my head. | [
"This is a fun question that pops up a lot from people first getting into quantum mechanics. From the point of view of electrons, electrons have intrinsic angular momentum. We know this because electrons have tiny magnetic dipole moments, which we know because you can send electrons through a magnetic field and the... | [
"It’s not spinning like a classical object, its just carrying an intrinsic angular momentum, just like it carries charge and mass."
] | [
"It just represents itself. As unintuitive as it is to our classical minds, it's just an intrinsic property of the particle, like mass or electric charge."
] |
[
"How could I solve this problem I made up that deals with time dilation and constant acceleration?"
] | [
false
] | null | [
"120 meters per second squared",
"RIP travellers. Anyway, these calculations are pretty straightforward and there's a few online calculators that do them for you.",
"http://i.imgur.com/D5whW7N.png",
"http://nathangeffen.webfactional.com/spacetravel/spacetravel.php",
"0.5588 meters per second",
"I assumed ... | [
"Thanks for that calculator; I didn't find it in my searches."
] | [
"Thanks for the help; that makes sense!"
] |
[
"In an old fashioned prop fighter plane, how do the machine guns on the nose not shear off the propeller?"
] | [
false
] | This confounds me. Is it a mechanism that only lets the firing pin engage at a certain prop angle? This seems sketchy. One mistake and kaput. | [
"There is indeed a mechanism to guarantee this. It's called the ",
"interrupter gear",
" and it makes it physically impossible to fire into your own propeller.",
"Good question!"
] | [
"The earliest planes actually had armor plating on the back of the prop, before the interrupter gear was developed. "
] | [
"there was a mechanism that would link the machine gun to the cycle of the engine so that the bullets would pass through the propellers instead of hitting them. the system was not perfect though, in a few instances pilots shot off their own propeller "
] |
[
"Why is the atmospheric pressure on Venus so high?"
] | [
false
] | Venus being about the same mass as earth, why is the surface atmospheric pressure is so high? Is there a general formula one could use to predict this? What are the parameters/variables involved in determining the basics of a planet's atmospheric values? Any insight would be appreciated! TIA! | [
"Okay the formula stuff I dont know, but the reason for the high ground pressure I do know. Basically all the water on the planet was turned to gas, clouds. CO2 built up from volcanic activity. Soot and other crap got launched into the air. The gravity of the planet kept the atmosphere from drifting off into space.... | [
"Thank you!",
"I now see how to visualize this!",
"So, if I understand you correctly, the atmosphere of Venus is more like a..... colloid, a soup, a fog, as compared with our atmosphere, yes?",
"Thank you ",
"/u/omnescient",
"! I think I get it :)",
"However, another question comes to mind:",
"Hypothe... | [
"Thank you!",
"I now see how to visualize this!",
"So, if I understand you correctly, the atmosphere of Venus is more like a..... colloid, a soup, a fog, as compared with our atmosphere, yes?",
"Thank you ",
"/u/omnescient",
"! I think I get it :)",
"However, another question comes to mind:",
"Hypothe... |
[
"Why hasn't life on Earth sparked into existence more than once?"
] | [
false
] | As far as I know life has "sparked" into being just once on Earth. I realise that theoretically life could have started multiple times and become extinct through history. But why don't we have multiple branches of life with multiple "alphabets" instead of "only" the GACT alphabet. If the conditions on Earth where so Goldilocks-like why don't we have different branches of life? Doesnt the idea that, despite the excellent prerequisites, life began only once on Earth throughout Earth`s history make the likely-hood of life being created elsewhere in the universe even more unlikely? | [
"It might have. Any new life that appeared would probably be unable to compete with existing lifeforms, and would be wiped out pretty quickly."
] | [
"Well, first off, it's probably best not to speak of life \"sparking\" into being. I presume this notion may come from the oft repeated bit about lightning striking the \"primordial soup\" and giving enough energy to create some new biomolecule or something. This new thing wouldn't suddenly have been \"alive\" thou... | [
"No, species adapt to their environment (including other species). They've evolved alongside each other to be highly competitive in their niche. Any new life would be starting out from scratch with no adaptations, which would most likely be a fatal disadvantage.",
"Edit: I'm a bit disappointed to see technotaoist... |
[
"Does anyone know of any decent studies done on the effects of tea that use subjects that actually drink tea as opposed to taking highly concentrated amounts of the things in tea?"
] | [
false
] | From what I have found, a lot of the health claims around tea (for better or worse) seem to be unsubstantiated or backed up with studies done either with large amounts of tea extract or concentrated components found in tea (caffeine, polyphenols, l-theanine), or reference research done on animals. Are there any conclusive studies done just on people drinking tea itself, or is this still kind of a fuzzy area? | [
"Studies have indeed been conducted on the prevelence of disease in tea drinkers compared to none tea drinkers. Once these showed that there may be health benefits, the mechanism behind them (what you seem to have found) is now being investigated.",
"This journal article seems to sum it all up pretty well and re... | [
"Thanks!"
] | [
"You presumably enjoy it, and it's fairly clear that it's not bad for you (unless perhaps you add lots of sugar), so does it really matter? How would it change your behavior if you knew you could take a pill to get the same effect?"
] |
[
"Equations for AskScience"
] | [
false
] | Would it be possible to get embedded LaTeX or something for AskScience so we can make our equations easier to read? Edit: I guess I'm looking for server-side solutions so everyone doesn't have to install the same plugins. | [
"http://latex.codecogs.com/gif.latex?(latex",
" code goes here, then copypaste the whole thing into address bar)"
] | [
"Using TeX:",
"Firefox/Opera",
"Chrome",
"Instructions"
] | [
"So you have to link a new page? I was hoping more for something that could be embedded in the comments.",
"Edit: ",
"test",
"\nAlso, that is a neat site; I will have to play around with it."
] |
[
"How is it that human brains work so much more differently than any of the others in the animal kingdom?"
] | [
false
] | I was taking a look at this video today of .. and it got me wondering - this is actually some very elementary problem solving skills for even a human teenager - yet how is it that elephants, with their large brain sizes, aren't able to "implement" something as simple as maybe use a branch to get the calf to hold onto and pull to dry land, or maybe entwine their trunks to get a good hold and pull, or maybe the ones with the longest trunks loop their trunk around the leg/knee of the calf and pull to the shore. I know that maybe the calf was waaaay too stressed to think cogently or listen to its mama's "explanations" - I'm sure they must have been "speaking" in elephant speak, but still... Is it that human brains have "evolved" so much that we are, these days, natural born problem solvers, and that other animals in the animal kingdom haven't had the need to get to humans' levels? What is preventing any other animal species from putting a man on the moon, or winning the Olympics or any other equal field where humans today have the sole hold over? The movie story of Rise of the Planet of the Apes comes to mind - have humans, in any way, prevented any other species from becoming an apex predators of the our planet? Or are humans ready for one? | [
"I'm not able to answer all your questions, particularly around our ability to limit other animals becoming apex predators (or indeed, more intelligent), but I can address some of your questions regarding our brains.",
"I should state, that we have not got a definitive answer as to why humans are so much more int... | [
"This is a lot of questions here. I think the best way to answer this is to say that humans, unlike most animals, are specialized tool users. Every solution you mentioned involves a tool of some kind, the cognitive understanding in how to use it, etc. This is not the core competency of an elephant.",
"Also, I do... | [
"Also, our problem solving and intelligence would look comparitively less advanced compared to other 'animals' if other ",
" species were still extant."
] |
[
"Why is it sometimes that something that interests me at first, will later leave me completely cold?"
] | [
false
] | null | [
"Science cannot answer your question directly, sorry. We can speak to how groups of people act at different time scales, but not you specifically. "
] | [
"I only took myself as an example. I'm assuming I'm not the only person who has this. I was just wondering why people do this in a more general sense"
] | [
"feel free to phrase a repost in a general way that can be answered scientifically"
] |
[
"How much of one's body weight is being lifted during a push up?"
] | [
false
] | null | [
"I think what you mean is \"how hard do I have to press down with my arms to raise my body when doing a pushup.\"",
"This is a problem of leverage. Your feet are the fulcrum. Your shoulders are the point where the force is applied, and you can think of all your body weight as sitting at your center of mass, wh... | [
"Good point, see reply to ",
"u/rooka8",
" ; I suspect it's a little bit arm weight, a little bit stability (for free weights), but it would be interesting to hear from expert physiologists or similar what they think."
] | [
"Doesn't that include the weight of your arms? Or rather, how much you put on a bar to bench disregards the weight of the arms?"
] |
[
"Could our universe be contained by a much larger system that obeys different laws of physics? And if so, could they interact?"
] | [
false
] | So, the analogy would be the relationship between the quantum realm and classical realm. This probably has been asked and answered before but I wasn't able to find it. Thanks! | [
"Theoretical physics deals with that kind of stuff all the time and is the very definition of not immediately verifiable (or falsifiable)."
] | [
"There are quite a few possibilities here, I'll summarize some of the more well-known ones. Note that all of this amounts to speculation, and none of it is proven, but it's not my speculation, but rather that of physicists working in these areas:",
"First, just from a mathematical perspective, if our universe is... | [
"No. It doesn't. Experiments are the essence of science. Models and theories are developed to explain available observations and must be able to make ",
" predictions. Without that, you're left with a very mathy way of blaming stuff on gremlins. ",
"Things involving strings or the embedding of our univ... |
[
"What happens to gravity at the very centre of a planet?"
] | [
false
] | My friend and I were talking about gravity and we couldn't figure out what happens to gravity at the centre of a spherical mass. Does it disappear at the centre? Does it get weaker going towards the centre as there is less mass underneath you pulling things downwards? Say you're 'standing' at a point in the earth around the boundary of the inner and outer core, would there be less gravity there than on the surface of the planet? Does the mass above your head pushing down count as gravity even though it's pushing and not pulling? | [
"There is a very relevant fact proved by Newton called the \"",
"shell theorem",
"\". It implies that inside any spherically symmetric shell, the total gravitational force is 0 wherever you are - even if you go much closer to one part of the shell than to the rest. ",
"Then you can use this to work out the gr... | [
"If there could somehow be a hollow sphere at the center of the earth, and if you were in the sphere, you would be essentially weightless because the mass of the planet would be pulling equally from all directions, sort of like a weird Lagrange point. ",
"Imagine two perfectly equal sized planetary bodies orbitin... | [
"That is really fascinating thank you!"
] |
[
"What sorts of problems does asymptotically safe gravity face as a potential quantum gravity solution?"
] | [
false
] | I've recently by Ethan Siegel over at Forbes (he also blogs at Starts with a Bang) on asymptotically safe gravity as a possible alternative to string theory. I read the author's blog from time to time, and he's described the potential benefits of asymptotically safe gravity, as well as the apparent prediction of a 126 GeV Higgs Boson years ago. My question is, what sorts of challenges does this idea face when it comes to quantum gravity? I feel like the buzz generated by an extremely accurate Higgs prediction, coupled with the ability to avoid adding entities like extra dimensions and supersymmetric particles, would be a huge positive in favor of asymptotically safe gravity. That being said, I do see much written on the subject and I wonder if that might be related to inherent problems or skepticism in relation to the framework. | [
"First of all, asymptotically safe gravity did not predict the Higgs' mass, since it has nothing to do with that. Also, string theory absolutely does not require low energy supersymmetry and large extra dimensions. They are very cool things that were easily accomodated into strings, and it would have been cute if t... | [
"Point two would be that this is a scale invariant theory and so predicts a volume-intensive entropy. As far as we know, all semiclassical development (i.e. black hole thermodynamics) until now requires area-intensive entropy. This whole program seems strongly at clash with everything we already know about quantum ... | [
"Arguably, unless you have a very developed imagination, it is not possible to make up a scheme through which information is conserved through collapse to black hole -> Hawking radiation which only involves local evolution.",
"Essentially, at the Planck scale we expect spacetime to be \"foamy\" and the causal str... |
[
"What would happen if there were no locks on the Panama Canal?"
] | [
false
] | [deleted] | [
"Yes, that's how a river works. However, what would actually happen is that both sides would drain towards each ocean. As you can see ",
"here",
" , What the locks actually do is get from level sea, up over the continent, and back down to the other side. The Pacific wouldn't flow to the Atlantic, or vice versa,... | [
"The reason for the locks is primarily that the canal level is higher in-between as it goes over land. If you removed the locks, water from the Gatun lake in the middle would run out both ends, and you'd ultimately be left with perhaps some small streams."
] | [
"Actually, without locks there would be saltwater flow since the atlantic is about 20cm lower than the pacific there."
] |
[
"Question on preferred methods for suicide for each gender"
] | [
false
] | Looking up some statistics on suicide, I've found that the most common forms of suicide in men are firearms and suffocation, and in females it is poison (drugs, ect). My question is what is the reason why men tend to use guns, and women tend to use drugs? Some related facts. Men successfully commit suicide 4 times as much as women, but women attempt suicide 2 to 3 times as often as men. I assume they attempt it more because they are more likely to not succeed with drugs, which is why i think this might be relevant to why they use drugs. | [
"That answer does sound pretty good, but I would like a source."
] | [
"Source(s)?"
] | [
"There's debate in the field. Some claim that women use suicide attempts as a cry for attention, without an intent to succeed, much more often than men, and therefore choose less lethal and more discoverable methods. Other claim that men simply have an affinity towards 'macho' methods such as guns and driving car... |
[
"Do gamma rays have radiation pressure too? If so, how?"
] | [
false
] | I can understand alpha and gamma rays exerting pressure because they have mass but, IIRC gamma rays are photons which are massless, so they can't exert a pressure. | [
"You're right, they are photons, but photons can exert ",
"radiation pressure",
" because they have a momentum, p = E/c, where the energy E = hf for a photon of frequency f, even though they have no mass. c is the speed of light and h is Planck's constant. Because they have a momentum, you can figure out the mo... | [
"The first comment is spot on, but I'd just add that the equation for momentum that OP is probably thinking of is the non relativistic one which of course doesn't predict that photons should have momentum. ",
"The proper equation for momentum includes a term that doesn't",
" "
] | [
"It's worth noting that the momentum is only imparted to an object if the photon interacts with that object by scattering or being absorbed. The simplest case (as in the figure in your wikipedia link) is reflection, where the momentum imparted is up to twice the photon's momentum (the direction changes while the ma... |
[
"When a nuclear bomb goes off, is the area immediately irradiated?"
] | [
false
] | I realize that it's almost instantaneously burned, but I'm wondering if the radiation comes from the initial blast or entirely from the fallout, which I thought was just ash. | [
"I realize that it's almost instantaneously burned, but I'm wondering if the radiation comes from the initial blast or entirely from the fallout, which I thought was just ash.",
"Short answer: yes.",
"The initial radiation takes the form of gamma and neutron radiation - this radiation dissipates relatively quic... | [
"Irwin Redlener on surviving a nuclear attack. Actual instructions being at 17:30",
"\n",
"http://www.ted.com/talks/irwin_redlener_warns_of_nuclear_terrorism.html"
] | [
"Irwin Redlener on surviving a nuclear attack. Actual instructions being at 17:30",
"\n",
"http://www.ted.com/talks/irwin_redlener_warns_of_nuclear_terrorism.html"
] |
[
"Why can't we test for mental illness like we can for other diseases?"
] | [
false
] | If we know depression for example is cause by a chemical imbalance in the brain, why can't be test the chemicals in the brain like we test for various things in the blood? By say looking for related animo acids, looking for trademark electrical signals of a reaction, or looking at metabolites. It seems very crude that we diagnosis such complex diseases using questions, not biologically. | [
"If we know depression for example is cause by a chemical imbalance in the brain",
"It really isn't. That's an oversimplified explanation used by pharmaceutical salespeople and ",
" doctors. ",
"The real situation is much more complicated and not very well understood. We know that inhibiting reuptake of serot... | [
"Part of the problem lies in our diagnostic system, which is built on observed combinations of symptoms and prioritizes reliability over validity. In other words, if you go to three different doctors, they should all come to the same diagnosis. However, the typical example of how this is imperfect is that a diagnos... | [
"The real thing missing though is the word \"yet.\" There is a huge field pushing advances in areas just such as this. ",
"The brain (well the body as a whole) is just a difficult place to study. There are countless entwined systems all affecting each other and each has to be taken into account. While some dis... |
[
"My dad doesn't believe that the light we see from stars originated thousands-millions-billions of years ago. Or that some of the star light we see comes from stars that died. How can I prove it?"
] | [
false
] | I've explained to him through a few ways such as if I fired a gun but then put the gun away, the bullet is still traveling in the same trajectory it was fired regardless of what happened to the gun afterwards and if I wrapped a fiber optic cable around the earth a trillion times, and shined a light in one end and saw it come out the other, there would be a delay. Also that the speed of light is some number in terms of meters per second which literally means it can only travel a certain number of meters per second. What can I show him? | [
"You will need a microwave and a large bar of chocolate and a ruler. (Your dad must first understand that microwaves and visible light are all part of the electromagnetic spectrum.) Take the rotating plate out of your microwave. Unwrap your chocolate bar and place it into the microwave. Turn the microwave on for be... | [
"Try explaining that the sun's light is 8 minutes away. If he can accept that, then he can accept that pluto's light is however far. From there, a simple map that shows scale should be sufficient. I'd say the 8-minute sun is the first example.",
"You can also say that we've PROVED the sun's light is 8 minutes aw... | [
"Most of the comments here are assuming that your father's problem lies in a refusal to accept science. But after looking into actual stars and finding that most of the notable ones are within 100 lightyears, I think he's making the much more reasonable argument that we can't actually see stars that are that far aw... |
[
"Which creature increases in body size most since birth?"
] | [
false
] | I'm wondering if you took the ratio from the mature adult form of an animal, and divided it by it's birth form what would have the highest ratio? Is it something huge like the blue whale, or is it some form of insect that (relatively) grows massively? Is it approximately the same for all animals? Thanks Ask Science. | [
"From what I know, in terms of length the largest growth % is likely the Lion's Mane Jellyfish, which starts off as a tiny clump of cells around one millimetre in length and eventually grows to be up to 37 metres long. This is a growth of around 3,700,000%, an change in order of magnitude of 10",
" .",
"In ter... | [
"While some jellyfish certainly are, the Lion's Mane is not."
] | [
"A colony organism is an organism that is actually made up of several seperate entities. A good example of this is coral, which is actually made up of thousands of separate polyps.",
"The Lion's Mane Jelly is not a colony organism."
] |
[
"What is happening chemically when cooking oil is heated past its smoking point and it begins to smoke?"
] | [
false
] | Wikipedia's explains how the fat is broken down into glycerol and free fatty acids, but I'd like to see an example chemical equation. Also, what are the health risks involved in consuming oil that has gone beyond its smoke point? | [
"It's pretty straightforward reaction. ",
"Here's a triglyceride with fatty acids and glycerol labeled.",
"Upon heating, oxidation occurs at the ester bonds, releasing glycerol and free fatty acids.",
"It's also possible that high heat can increase the presence of free radicals, which are highly reactive. A... | [
"That reaction may very well occur, but it isn't the cause of the smoke. The smoke is caused by pyrolysis of the resulting fats and alcohols, leading to decomposition of the molecules by scission of C-H (and probably C-C) bonds, which re-form as small (usually toxic and bad-tasting) organic molecules by reaction wi... | [
"So, what is the result of repeated heating and cooling cycles on such a material? Assuming it is kept below the smoke point or thermal decomposition point."
] |
[
"There has been a lot of anti-ADHD rhetoric going around lately. Do we have proof that ADHD (especially in adults) is actually a disorder? Or are people like me truly just lazy, awful people?"
] | [
false
] | null | [
"ADHD is listed on the ",
"DSM",
", which means that it is considered a real clinical disease at the moment. However, that does not mean it will always be so (homosexuality was listed on the DSM in the past). But given what we know about ADHD, it is likely a 'real disease'. For example, there is a significan... | [
"It is probably a \"real disease\" but the problem is that it gets over-diagnosed for children and adults that don't actually have anything wrong with them:",
"http://www.sciencedaily.com/releases/2012/03/120330081735.htm",
"The study showed that child and adolescent psychotherapists and psychiatrists tend to g... | [
"For example, there is a significant genetic component, with greater concordance between monozygotic vs dizygotic twins.",
"The same could be said for ",
"homosexuality",
", so I'm not sure your evidence for \"real disease\" for ADHD logically follows."
] |
[
"Is there a \"minimum\" viscosity for the shatter effect to take place?"
] | [
false
] | Extremely high viscosity liquids shatter when struck with enough speed and pressure. Would low viscosity liquids appear to shatter in a similiar way if viewed on an incredibly ultra high speed camera is stuck withenough speed or force? Or is there a "minimum" viscosity for the shatter effect to take place? | [
"I can't directly answer your question. First instead of the shatter effect I'm going to use the term brittle fracture. The phenomenon you're referring to is known as shear thickening which occurs in some non newtonian fluids. During shear thickening, the viscosity of a fluid increases with increased strain rat... | [
"First off we're likely talking about polymers where the traditional crystal lattice and slip do not exist. Second we're clearly talking about viscoelastic non newtonian fluids. The definition of shattering does apply. When you pull silly putty quickly it shatters, fractures what ever you want to call it. We all... | [
"Please explain to me how shattering could mean anything other than brittle fracture. I think if the person asking the question knew the exact nomenclature to use they'd also know the answer to the question. Viscoelastic behavior is a pretty materials concept. "
] |
[
"Does a method exist for organisms to prevent mutations from occurring?"
] | [
false
] | Are there safeguards to prevent mutations from occurring, either by killing off cells with an faulty gene or repairing damaged DNA? Are there organisms that are more capable at this than others? | [
"Yes, actually most (if not all) living being with dna possess quite effective process that repair dna, ie cancel mutations by returning the dna into its pre-mutation form.",
"This page from the nature website, explain the most well-known of them : ",
"http://www.nature.com/scitable/topicpage/dna-damage-repair-... | [
"Yes, and the best example is actually the naked mole rat. It sounds made up, but its basically immune to cancer. Some other animals are very prone to cancers. ",
"Even within the same species, the sexes can have different kinds of cancer protection. Men have a much higher chance of brain tumors because we do not... | [
"This, nearly all organisms have various proteins involved in replication that \"spellcheck\" DNA looking for things like physical bumps or kinks caused by mismatching base pairs. Humans have multiple proteins that work on DNA during replication and protein production that have the ability to cut out or \"excise\" ... |
[
"Can film exist in a format that isn't a series of still frames? Whether analog or digital?"
] | [
false
] | Instead of many still images creating the illusion of motion, are there other ways of depicting film without a film reel with separate negatives (analog) or a video file (digital) without frames? | [
"If you're asking about the storage of video, there's no need to keep each frame stored separately. Normal video codecs today only store some frames called keyframes. For all other frames, only the difference between the precious frame is stored, as this can be compressed more efficiently.",
"You could theoretica... | [
"Regarding the last paragraph, there would exist a Fourier series whose partial sums would approximate the brightness of the pixel at each time as close as you wanted.",
"In fact, instead of Fourier series, one could use wavelets. Further, one might use \"different\" wavelet bases (? not sure if this is the corre... | [
"If you ignore the fact you're viewing it on a computer screen (which has a refresh rate and therefore 'frames'), vector animations can sort of do this.",
"Something like a flash animation - you don't store each frame normally, you store each object's start point and end point.",
"So if I had a square at T-0 Se... |
[
"Are there examples in nature or experiments where animals with less desirable traits but more resources attract more mates?"
] | [
false
] | The title sums it up, less desirable traits being things like older age or weaker physical attributes, and more resources I guess meaning food stock piles or superior "housing" setup. Of course, in nature if a weaker or older creature has resources, the more fit one will usually just take them so that's why I wonder about this experiment. Trying this again as first was marked spam for some reason. | [
"I forgot the name of the bird but it collects anything that is blue to put in its nest to attract females ( saw it on planet earth)"
] | [
"Sunfish have a weird little ternary arrangement where colorfull super alpha males make and guard nests and drab beta males mimic females and fertilize eggs just as the real female produces them by sneaking into the nest at the strategic moment. ",
"Not sure if it counts by your standards."
] | [
"Most animals don't have 'resources' the way humans do. Many species, including chimps, will trade food for sex directly. Many birds create elaborate nests to attract mates, which I guess could be considered a 'resource', but is more of a costly display in line with a peacock's tail.",
"Beyond that, I'm not sure... |
[
"What does it feel like to be given high doses of radiation?"
] | [
false
] | null | [
"\"Radiation\" isn't one single thing. Some are massive particles, while others are massless. Some are a ionizing, some aren't.... You get the idea.",
"What kind of radiation?"
] | [
"I suppose gamma radiation. Or something along the lines of chernobyl."
] | [
"Chernobyl is an unwieldy case to use, since the death toll varies wildly by source. Unless your question is really nuclear power-based, it looks like what you're asking about is ",
"Acute Radiation Syndrome",
", or radiation poisoning. It's a quite complex array of symptoms, depending on how much exposure to w... |
[
"Is a singularity reactor possible?"
] | [
false
] | I have been thinking, and it seems something like this would be theoretically possible. It all comes down to Hawking radiation and the evaporation of black holes. Large black holes evaporate incredibly slowly, but small black holes (like the kind the LHC might create) evaporate incredibly quickly. What if this effect could be harnessed? Imagine using an array of very powerful lasers to create a micro-singularity. Almost immediately, it starts evaporating. But you don't let it collapse. You keep feeding matter onto it, such that the mass flow cancels out the mass loss due to hawking radiation. It would seem to me that with such a setup, you've just made the perfect energy source. You have a system that converts mass to energy with 100% efficiency, much better than fission or fusion. You could use a reactor like this to produce abundant energy ANYWHERE. You don't need fossil fuels, sunlight, uranium, or deuterium; any mass will do. You could probably power a relativistic spaceship with it, gathering mass from the interstellar medium as you go. Any thoughts on this? | [
"The problem is, you'd have efficiency losses both maintaining the singularity and capturing the energy from the Hawking radiation. Furthermore, we don't even have the technology to create a sustained fusion reaction, and what you're talking about would be several orders of magnitude more difficult.",
"So is it... | [
"You could use a reactor like this to produce abundant energy ANYWHERE. You don't need fossil fuels, sunlight, uranium, or deuterium; any mass will do. You could probably power a relativistic spaceship with it, gathering mass from the interstellar medium as you go.",
"Did you not see what happened in ",
"?"
] | [
"I love that movie. I am fully aware that it is silly. I don't care."
] |
[
"Why do i sneeze when i go outside and its really bright out?"
] | [
false
] | null | [
"Some people have a ",
"photic sneeze reflex"
] | [
"Sneezing as a result of looking into a bright light is known as the \"photic sneeze reflex,\" and is a genetic trait that about one third of all humans have.",
"The last I checked, however, there was no definitive explanation as to why it happens. If anyone has some good documentation on the subject please post... | [
"In medical school physiology one instructor said it was probably because of the proximity between two nerves - the nerves which constrict the pupil may \"crosstalk\" to stimulate the nerve that senses touch inside the nose.",
"Looking for sources just now, I also found ",
"this",
" describing a similar sneez... |
[
"If the photo \"pale blue dot\" (a photo of the earth) was taken from 3.7 Billion miles away, how does it not contain the rest of our milky way galaxy in the photo?"
] | [
false
] | null | [
"The image only covers a small angle - much like how zooming in on your camera means you don't see as much background."
] | [
"I see. So is the image magnified that much that the next closest planet is out of the field of view? "
] | [
"Very much so! It really is quite zoomed in on Earth.",
"Perhaps more interesting is the \"updated\" image that was taken by the Cassini mission, ",
"here",
". The Sun is behind Saturn, which is what you're viewing the back and rings of, with Earth being the dot between the bright inner rings and middle faint... |
[
"Are there nerves in the umbilical cord?"
] | [
false
] | I'm talking about the human umbilical cord, specifically, and I'm curious whether newborns feel anything when it's cut. | [
"No. The only structures in the umbilical cord are two arteries and a vein, unsurprisingly called the umbilical arteries and the umbilical vein. The cord's not even made of muscle or skin. It's composed, apart from those blood vessels, of a substance called Wharton's jelly, which is the same kind of stuff that fill... | [
"Umbilical cord contains 2 arteries, 1 vein and a substance called Whartons Jelly that gives the cord its shape and protects the arteries/veins from being occluded.",
"The next part is me thinking to myself, and not a scientific answer... the cord is not meant to contain any nerves, yet for breech births and cord... | [
"The umbilical cord and placenta are tissue produced by the fetus. That should answer your hypothetical."
] |
[
"How does a master key work?"
] | [
false
] | null | [
"The master key itself is nothing special, the trick is in the locks set up to accept the master key. Most locks have a set of metal bars called pins, that prevent the lock from turning. A regular key pushes these pins to a precise height, moving them out of the way and allowing the lock to turn. Locks set up for a... | [
"Bingo. You have two possible correct heights to pick each pin to, instead of just one."
] | [
"Does that mean that a lock with a master key is easier to pick, because there are more correct combinations of pins?"
] |
[
"Can humans breed with any other species?"
] | [
false
] | [deleted] | [
"Some relevant reading"
] | [
"Non-coding DNA is quite a bunch of stuff: flow control, dead code, comments, noops, and stuff which you didn't even know could parse and sure as hell are not going to touch."
] | [
"HIV was almost certainly contracted from ",
"bushmeat",
", since chimps and apes are both occasionally hunted for food in certain parts of Africa. The rates of transmission for HIV through sexual intercourse ",
"actually aren't terribly high",
", which is why behavioral patterns which increase risk through... |
[
"Is there a difference between long-term memory that gets used daily and memory that doesn't, and is it possible to have brain damage which causes loss of memory that doesn't?"
] | [
false
] | Is is possible to have severe head trauma that causes nearly complete loss of long-term memory after three to six months, and are there any other symptoms (possibly ASD-like) that would result from this kind of injury? I've just heard of short-term and long-term memory loss, but never this medium-term kind of thing, and looking over Wikipedia implies that the brain doesn't work this way and it shouldn't happen. So we're curious, that's all. | [
"In a way yes, I just saw an article about how the brain has mechanisms for long term memory and for memory loss. Heres the article, it also has other cool info too. ",
"http://brainblogger.com/2015/11/08/best-and-worst-of-neuroscience-and-neurology-october-2015/"
] | [
"As far as I am aware there's only retrograde and anterograde amnesia, but nothing in between in regard to TBI. Generally, I believe that newly formed memories are more fragile than older ones, but I think it can also depend on the strength of the connections. Memories you don't use as often would be more fragile ... | [
"No the article described had nothing to do with amnesia but only the natural mechanisms of filtering out memories so that the brain can save energy and become more efficient."
] |
[
"What is physically different between the brains of people with \"good memories\" versus those with \"bad memories\"?"
] | [
false
] | Some people naturally have stronger memories than others, is there a difference in the physical structure of two peoples' brains with varying strengths of memory recollection? Some people are very good at remembering conversations, obligations, directions and events. However some people can be the complete opposite. Is there a difference in the anatomy or function of their two brains that cause this? | [
"The ",
"hippocampus",
" is a part of the brain that plays a very important role formation of new memories. If a person has structural damage to the hippocampus, that causes issues with forming new memories. Alzheimer’s disease, for instance, is associated with ",
"hippocampal damage",
"--and memory loss is... | [
"Thanks for answering!"
] | [
"Great question!",
"This is a new direction of research from my ",
"former post-doc advisors lab",
". ",
"Daniela Palombo",
" developed a survey called the Survey of Autobiographical Memory that allows people to rate themselves on their memory for personal experiences - episodic memory, facts - semantic m... |
[
"How likely is the Fukushima nuclear crisis able to cause a worldwide environmental catastrophe?"
] | [
false
] | [deleted] | [
"I think you missed some of the question. If any of the reactor buildings were to collapse and cause loss of shielding over the spent nuclear fuel, you may not be able to get humans in the area anymore. Abandonment of the site could release radioactive particulate several orders of magnitude beyond Chernobyl. That ... | [
"Reason being, Fukushima already avoided a meltdown",
"Full nuclear meltdown in Fukushima admitted by Japan"
] | [
"I guess if you can't dazzle them with brilliance, baffle them with bullshit. How does any of this justify giving dangerous medical advice or intellectual dishonesty?"
] |
[
"What is an example of two very similar chemical formulas behaving very differently?"
] | [
false
] | I remember someone illustrating this for me with a very good example but I forget what it was. I have someone arguing that baking soda is like lye because the formulas are similar... EDIT: He's saying that baking soda dissociates to lye in water. | [
"There are many examples of this. The chemical formula itself is often not a good indication of its properties, rather, a compound's structure is often important. Take for example the formula C4H8O2. Two ways that we can arrange those atoms is as ",
"ethyl acetate",
" or ",
"butyric acid",
". Those two comp... | [
"I think thalidomide is one of the most famous examples. It was used as a morning sickness drug in the fifties or sixties. It is a chiral compound, meaning the same molecule has two configurations which are non super-imposable mirror images of each other. (Think your left and right hand.) One configuration was s... | [
"Cisplatin, the anticancer drug, versus transplatin, which is almost chemically identical, but extremely ineffective as an anticancer drug."
] |
[
"Physicists, what are your opinions about the Feynman Lectures? Are they still worth reading?"
] | [
false
] | I have all of them and I am interested in self-learning physics, as I am doing with differential equations and linear algebra. Are these good books, or should I find something else? | [
"Great books. Totally worth working through."
] | [
"Hey, a QFT specialist! I have a question for you specifically. If you somehow had the money to support your living expenses (say you inherited a large sum from your distant Nigerian relative), would you be able to study QFT or any other form of mathematical physics by yourself, provided that you could get almost a... | [
"Do you need an advanced degree? Gerard 't Hooft has posted a ",
"list of resources",
" that might get you to the point of learning what you need to learn. I don't think you need an advanced degree ",
", but I don't think I could have learned to be a theoretical physicst without having been in a university e... |
[
"How much would celebrities net worth weigh in $100 bills?"
] | [
false
] | null | [
"Here's a photo of a billion dollars.",
"http://3.bp.blogspot.com/_jhf-7wU76qc/TGmkUNmohuI/AAAAAAAABXY/rJnOh2MYi9Y/s640/billion_dollars_cash_3.jpg",
"Bill gates is worth about 80 of these. Or roughing it up a bit, about 1000 of those individual pallets of $100 bills."
] | [
"This is pretty easy, since a ",
"bill weighs about 1 g",
". So, according to ",
"this page",
":",
"George Lucas = $ 5.1 billion = 51 metric tons (of 100 dollar bills)",
"Steven Spielberg = $ 3.5 billion = 35 metric tons",
"Oprah Winfrey = $ 3.2 billion = 32 metric tons",
"Wolfram-Alpha tells me the... | [
"A dollar bill (any denomination) is about 1 gram, Which gives you about 454 bills per pound. Using $100 bills, that's $45,400 to the pound or $90,800,000 to the ton.",
"Bill Gates' net worth is $79.2 billion. $79,200,000,000 divided by $90,800,000/ton gives you 872 tons.",
"$1 million (in $100s) is about 22 po... |
[
"Does gravity have a range or speed?"
] | [
false
] | So, light is a photon, and it gets emitted by something (like a star) and it travels at ~300,000 km/sec in a vacuum. I can understand this. Gravity on the other hand, as I understand it, isn't something that's emitted like some kind of tractor beam, it's a deformation in the fabric of the universe caused by a massive object. So, what I'm wondering is, is there a limit to the range at which this deformation has an effect. Does a big thing like a black hole not only have stronger gravity in general but also have the effects of it's gravity be felt further out than a small thing like my cat? Or does every massive object in the universe have some gravitational influence on every other object, if very neglegable, even if it's a great distance away? And if so, does that gravity move at some kind of speed, and how would it change if say two black holes merged into a bigger one? Additional mass isn't being created in such an event, but is "new gravity" being generated somehow that would then spread out from the merged object? I realize that it's entirely possible that my concept of gravity is way off so please correct me if that's the case. This is something that's always interested me but I could never wrap my head around. Edit: I did not expect this question to blow up like this, this is amazing. I've already learned more from reading some of these comments than I did in my senior year physics class. I'd like to reply with a thank you to everyone's comments but that would take a lot of time, so let me just say "thank you" to all for sharing your knowledge here. I'll probably be reading this thread for days. Also special "thank you" to the individuals who sent silver and gold my way, I've never had that happen on Reddit before. | [
"Yes, gravity has infinite range and changes in gravity propagate at the speed of light. It's a very analagous with electromagnetism, ie electric/magnetic fields and electromagnetic waves.",
"Every piece of matter in the universe is attracted to every other piece of matter in the universe. And when wild things ha... | [
"If you’re wondering why would gravity waves just so happen to have the same speed as light, even though they would not seem to have a direct relationship, it’s because the speed of light is not actually specifically about light; it’s about ",
" Calculations show that if any kind of information-bearing phenomeno... | [
"This is because there are no negative mass particles. Electrical shielding works because dipoles in the material can arrange themselves to cancel out an external field. Without negative mass particles, you can't have a gravitational dipole."
] |
[
"Have we ever observed an object (such as an asteroid or comet) from another solar system come into our solar system?"
] | [
false
] | null | [
"We did for the first time last year",
"https://en.wikipedia.org/wiki/%CA%BBOumuamua"
] | [
"Basically,",
"is only travelling at 17 km/s",
"plane of the ecliptic",
"approached the solar system at a completely different angle"
] | [
"How do we know it wasn't a perturbed object from our own system that was sent on a hyperbolic trajectory before we discovered it (e.g. A comet or asteroid that had an accidental 'gravity assist' from a giant planet)"
] |
[
"Assuming that the universe is expanding, what would happen with a light beam, which is emitted from a star, who is located at the horizon of the expanding universe, in the direction of the horizon?"
] | [
false
] | null | [
"or do my questions or assumptions not make sense at all?",
"It's a common misconception that the universe is expanding \"outwards\" like a balloon. The universe is expanding at all directions and there is no single point of origin for the expansion. The only horizon we observe is from the ",
"observable univer... | [
"thanks for the answer but i am aware that the universe is not expanding outwards. but i didnt want to use the term \"observable universe\" either, because observable universe only means that we can observe it. I am talking about a Star at the \"end\" of the universe (assuming that the universe is finite)"
] | [
"There is no \"edge\" of the universe per se as covered: - ",
"http://www.reddit.com/r/askscience/comments/mbw2x/what_would_happen_when_you_reach_the_end_of_the/",
" ",
"http://www.reddit.com/r/askscience/comments/kn075/does_the_universe_have_an_end_what_would_it_look/",
"\n",
"http://www.reddit.com/r/as... |
[
"Should the Observable Universe be Described as Three Dimensional or Four Dimensional?"
] | [
false
] | I ask because I have always thought it would be considered 4D (length, width, depth, and time as the forth). But I often find myself seeing things that refer to only 3, then the extra-dimensions in regard to string theory, and time is dumped in at the end. Since time is observable should it be counted in with length width and depth? is the most recent example of an article that list things in the manner I'm questioning. | [
"Personally, as a physicist, I prefer to ",
" our universe is 3-dimensional to the layman. This is because the temporal dimension is related to the spatial dimensions in a different",
" way than the spatial dimensions are related to themselves. I'm very hesitant to call the universe 4D because of this, because ... | [
"If you do tell laymen that the Universe is 3D, especially a group of laymen as interested as the ones on askscience, I'd suggest at least mentioning the caveat about diffeomorphism invariance, i.e., that there's no unambiguous way to slice the Universe up into 3D constant time slices. I think most interested layme... | [
"Three extended spatial dimensions, one time dimension, and possibly six or seven compactified spatial dimensions (if string theory is correct), so it just depends on what you mean when you say \"dimension.\""
] |
[
"What is the current \"standing\" of cosmic inflation, specifically re: BICEP 2's findings?"
] | [
false
] | I've been digging about on Google, but I was hoping that some folks here might have better resources and info. | [
"It's not any different than before BICEP2 first announced their results. Most working cosmologists still think it's (by far) the best theory of the very early Universe we have to date, because it does predict a lot of the very specific features we've observed in the CMB's temperature fluctuations.",
"But as for ... | [
"Basically, and someone more familiar with the experiments can explain further, it's this:",
"BICEP2 released their results, on arXiv.",
"Critics point out that if the dust foreground was much much bigger than what they assumed it would invalidate their findings.",
"BICEP2 pointed out that they did take dust ... | [
"Critics point out that if the dust foreground was much much bigger than what they assumed it would invalidate their findings.",
"BICEP2 pointed out that they did take dust into account using data from the Planck mission, and it's insignificant compared to their observed signal.",
"BICEP2 paper is published in ... |
[
"Why do bee stingers come off?"
] | [
false
] | null | [
"Human skin is very thick and they get stuck. When they sting other things, they do not get stuck."
] | [
"https://en.m.wikipedia.org/wiki/Bee_sting",
"See the honey bee section"
] | [
"Oh really?\nCan you show a example?"
] |
[
"How do optical illusions appear to be moving?"
] | [
false
] | like these | [
"I'm an artist who creates optical illusions. The big reason this particular type of illusion works is because the value of the lines lead the eye. Other moving illusions can force the perspective with the thickness of the lines. It is the same principle shown in ",
"this famous illusion",
" but much simplifie... | [
"If I stare at an optical illusion long enough, will I get used to it, and see it as a regular, picture which doesn't move?"
] | [
"No, though if you allow your eyes to unfocus and see the picture as a gestalt it will stop moving."
] |
[
"Is the habitable zone of a 2-star system further out than a single-star system like ours?"
] | [
false
] | null | [
"Depends, but often not really.",
"Binary star systems can have any of a huge variety of separations, from so-called ",
"contact binaries",
" to a decent fraction of a light-year (Proxima Centauri is ~0.21 ly from Alpha Centauri A&B). Or maybe more (Fomalhaut gets silly).",
"If the stars are similar in mass... | [
"Fomalhaut B is 0.28 pc (0.91 ly) from Fomalhaut A. Fomalhaut C is 0.987 pc (3.22 ly) from Fomalhaut A.",
" Figuring out that Fomalhaut was a multiple star system was slightly difficult because the components are separated by ",
"."
] | [
"Fomalhaut gets silly",
"What are you referring to?"
] |
[
"A question about human population movements"
] | [
false
] | While I was listening to NPR's science Friday, they were talking about the evolution of human languages. One of the languages they featured was Hawaiian and I thought of the following question for you guys... How did human beings manage to populate all of the remote Southern Pacific islands? When all of this happened they had no way of knowing that if they sailed out into the ocean in a small boat that there was anything there. Was it just trial and error? It seems like it would take a lot of voyages of multiple people to succeed if people just randomly launched ships. | [
"Wikipedia Link to Polynesian Navigation",
"Since you mentioned Hawaii, Polynesians were a pretty extensive sea faring civilization, so it wasn't a matter of launching a boat and risking it never coming back.",
"Rather than looking at it as a haphazard jump in a boat and see what happens situation, think about ... | [
"The people you are talking about are Polynesians, they lived on small islands around the pacific and had developed ways to navigate to other islands. For example clouds tend to cluster around islands, navigation by stars, direction of swells.",
"Then again you need results for any rules so I suppose originally i... | [
"TIL Polynesians were the equivalent of ancient astronauts."
] |
[
"If our sun were a white dwarf, would it still be the brightest in our night sky? If not, where would it rank?"
] | [
false
] | null | [
"If it were a white dwarf, it wouldn't appear in our night sky. Night time is when you're facing away from the sun.",
"Source: any dictionary ever written."
] | [
"A typical white dwarf has absolute magnitude between 10 and 15 (where a higher number, counterintuitively, means a lower brightness), so the apparent magnitude of a white dwarf at the distance from the Earth to the Sun ranges from about -16 to -21. The Sun has an apparent magnitude of about -26, so a white dwarf w... | [
"Of course - I was just comparing it to something you know, since that seemed helpful for visualizing a white dwarf in our Sun's place."
] |
[
"What is polarized light?"
] | [
false
] | I came out of Jurasic Park 3D the other day, and noticed that the 3d glasses were polarized when I saw them black out the screen on my phone. What differentiates polarized light from regular light? | [
"So as a photon travels along the x-direction, it has a magnetic field which oscillation in the y-axis up and down and an electric field which oscillation in the z-axis ",
"see here for visualization",
"So the photons are still travelling along the x-axis ",
" you, but can be angled differently. ",
"Taking ... | [
"Your second link really clears it up nicely. The light wave is in 2d, but it is rotated around the Z axis. So does this mean that unpolarized light (like sunlight) consists of a multitude of photons coming at you at random angles?"
] | [
"Related question, when a polarizing filter allows a light to pass through is it the electric field which is aligned with the filter or the magnetic field?"
] |
[
"Because of the commonness of depression in humans, is it probable that it has some adaptive quality that has been selected for?"
] | [
false
] | null | [
"Not depression, per se, but the kinds of kinds of personal traits needed during difficult times -- existential worry, stress over resources, deep concern over abstract problems -- are far less adaptive when there is no current emergency. Living, as most people do, with the relative certainty of long life and rela... | [
"Mental illness, at least, as we experience it, basically doesn’t exist in hunter-gatherer societies. We are not built for the world we have created any more than cheap food suits our diets, cheap housing suits our needs, and work suits our bodies.",
"The sooner we acknowledge that and begin actually building a w... | [
"Off the cuff, I doubt it. Modern life, at least in wealthier countries, has effectively eliminated selection pressure in humans in terms of fitness. I suspect the prevalence of depression has more to do with work, diet, and other stressors that we weren’t really “built” for.",
"Or maybe there’s a very successful... |
[
"Why is it that some tasks are much more easily performed while not thinking about what you're doing?"
] | [
false
] | null | [
"The short answer is that your consciousness is rather limited in processing power compared to your subconsciousness. If you practice a task enough while using your consciousness, a lot of the specifics in the task will be transferred to the subconsciousness. Until the task is practiced enough, you won't be able to... | [
"http://en.wikipedia.org/wiki/Procedural_memory#Expertise-induced_amnesia",
"A reported 16.6 million Canadians watched Sidney's goal, and it's safe to assume that most of them would have been able to easily recollect the details, but not Crosby; he was immersed in an automatic state that at least temporarily bloc... | [
"upvote for hockey reference."
] |
[
"I have a booklight with a fluorescent light bulb that, when turned on, will not light up if the room is darkened. It lights immediately if the room is itself illuminated. What exactly is going on here?"
] | [
false
] | null | [
"My specialty is lighting and optics. I have never heard of this happening without a photosensor being involved.",
"Is the book light plugged into the wall or battery operated? Are you absolutely sure the start up time of the lamp is faster when exposed to other light than when in the dark? Is there a small photo... | [
"as a test, i would suggest you actually time this, with a cold bulb (i.e. one that was not on previously, for perhaps 12-24 hours prior)",
"1) first condition - time how long it takes for the bulb to come on, from cold, in the dark.\n2) second condition - time how long it takes for the bulb to come on, from cold... | [
"I can answer most of these. Number 1, the answer varies. Sometimes it takes 5 seconds, sometimes it takes as long as 30 seconds. It actually kind of depends on how run-down the booklight's batteries are. I should have mentioned this before, but this effect only starts happening when the batteries (4 AAs) are run... |
[
"Do Iodine tablets prevent radiation sickness?"
] | [
false
] | Saw Iodine being administered in two separate TV shows. Does it really help? How does it work? | [
"Not exactly, a large amount of the radiation dose from a nuclear explosion comes in the form of a radioactive isotope of iodine. You take large doses of safe iodine and that means your thyroid won't absorb the radioactive one, and you'll just piss it out instead of ending up with a radioactive thyroid."
] | [
"Iodine supplements only protect against one particular way in which fallout can hurt you. It does no good against acute radiation sickness or other radionuclides other than 131I. But it's cheap and easy, and protecting against one thing is better than protecting against zero things. ",
"Think of it like wearing ... | [
"This is actually not that uncommon of a treatment type. For example, if you drink antifreeze accidentally, one treatment is for you to drink a bunch of normal alcohol, because it keeps your ",
" liver busy while the antifreeze passes (antifreeze isn't toxic in and of itself, but what your liver creates after pro... |
[
"Would a lander be able to land on Io, Jupiter's volcanic moon?"
] | [
false
] | null | [
"Yes, but the thin atmosphere requires retrorockets to slow a lander for soft landing, and strong radiation shielding.",
"Here",
" is a mission profile."
] | [
"Would something like Curiosity's Sky Crane be suitable for such a landing?"
] | [
"Possibly, but before the sky crane deployed Curiosity, aerobraking was done with a parachute. Mars has between 2 million and 20 million times the atmosphere of Io, so there's still a significant challenge in shedding velocity."
] |
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