title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"How close could I get to this cold brown dwarf without dying horribly?"
] | [
false
] | I saw and wondered about if I could, theoretically, interact with such an object. I presume gravity would be the main issue, or would it? Let's assume it's on the lower bound of mass for a brown dwarf. Could I approach it in a space suit of some kind? It is just a warm 25 C there (or 77 F for those wondering), so t... | [
"Layman here.",
"It wouldn't be very much unlike Jupiter. If you had a spaceship that could orbit around Jupiter, you could orbit around a brown dwarf that cold with no problems. You wouldn't want to get so low that atmospheric drag would slow down your orbit; you'd eventually crash into it.",
"\"Crash into\" i... | [
"Jupiter is not necessarily just huge ball of gas. Jupiter very likely (no real confirmation on this, but, very likely nonetheless) has a core that is at minimum a very hot liquid or maybe solid, we don't quite know. It is likely surrounded by molten hydrogen metal while the deeper portion contains rock an... | [
"There's always someone that picks obvious holes in what's clearly a hypothetical question..."
] |
[
"Why does the US Department of Energy have so many Supercomputers?"
] | [
false
] | null | [
"Nuclear research and planning. There are a lot of rules and restrictions regarding physical nuclear research, so most of it has to be modeled by computers. As you can imagine, modeling nuclear reactions is extremely complicated because it requires modeling the interactions of large numbers of subatomic particles... | [
"Well obviously they hold the responsibility for nuclear reactors, but what a lot of people don't realize is that they are responsible for nuclear weapons as well: ",
"http://en.wikipedia.org/wiki/United_States_Department_of_Energy#Responsibility_for_nuclear_weapons",
" ",
"The military would be responsible ... | [
"I am a physical chemist at Argonne National Lab (and the University of Chicago), which is ran by the DOE. ANL runs a number of super computers. Like others have said these computers are used for all sorts of energy related research (not only nuclear, but all types of research the DOE funds). They are also made ava... |
[
"A quick question regarding the speed of light."
] | [
false
] | Hey reddit. I had a few questions pertaining to the speed of light.. Could someone please explain to me how light works. I'm trying to understand how we're able to see light from distant planets/universes. How far can light travel (in space)? Is it infinite? Is it finite? If it is finite, does that mean we can't see ce... | [
"It travels until it is absorbed. If nothing absorbs it, it goes forever. However, if a source is distant enough, the light gets spread out to the extent that we can't see it with our eyes anymore. That's why we use telescopes and digital cameras."
] | [
"More like a shotgun blast. Imagine that at a given distance from a light source, photons are equally distributed along an imaginary sphere with a radius of that distance. When you go twice as far away, there are the same number of photons but spread over a surface four times the size, so the density of photons is ... | [
"Light can travel forever, uninterrupted, in empty space, so there is no limit to how far it can potentially go. In this respect, it is \"infinite\". ",
"However, the universe is only 13 billion years old, so there are some things in the universe that are so far away that light from them has not had enough time ... |
[
"If you took the DNA out of an ovum and put it in a sperm cell, could use use that to make a fertilized egg?"
] | [
false
] | I imagine the inverse of this work not work out nearly as well. Edit: to be more clear, lets say I took the DNA from an ovum, and put it in a sperm cell. I then took that sperm cell, and used it to fertilize a second egg. Basically artificial insemination involving no male's DNA. | [
"My understanding of the question being asked is different from some other posters', so I'll rephrase my interpretation of it:",
"Could you take the DNA from one egg and use it to fertilize another?",
"I believe this is how asexual lizards reproduce, but I don't know enough about them to be confident of that. G... | [
"This one is easy. It really is impossible for a number of reasons. One is that there are certain reactions that have to occur to the egg in order for it to activate. The big thing that makes this impossible is the fact that you have specific maternal determinants (proteins and mRNA) that are found in the ovum and ... | [
"Yes, this is the question that I was getting at."
] |
[
"How much immunity is typically conferred 6 days after a vaccine?"
] | [
false
] | null | [
"Had to sleuth for quite a while to get anything remotely related to my query; while I could not find a precise breakdown of days or weeks; this is probably the next best thing from ",
"https://www.healthline.com/health/why-two-doses-of-covid-vaccine",
" : ",
"Pzifer 1st dose",
"Researchers working on the c... | [
"Effectively none"
] | [
"Please read my answer which actually includes some data: ",
"https://www.reddit.com/r/askscience/comments/mns0nz/how_much_immunity_is_typically_conferred_6_days/gtzqdyz/?utm_source=reddit&utm_medium=web2x&context=3"
] |
[
"Antimatter Spin"
] | [
false
] | I'm hoping someone can settle a problem we're having over in ELI5, in a thread on antimatter and blackholes. Some of the sources we've found say that antimatter is the same mass as matter, with opposite charge and spin; other sources say both mass spin are the same, with only the charge being opposite. Can anyone cle... | [
"imsowitty has the closest to a correct and complete answer. When talking about spin, there are two things to take into account: the spin itself (you could think of it as magnitude) and the spin projection (classically, you would think of it as direction). Since spin is ",
" positive, it doesn't make much sense t... | [
"If an electron and anti-electron are simultaneously created, one will have spin 1/2 (in some direction) and the other will have spin -1/2. The two particles in this particular pair have opposite spin.",
"Depends on how they're created. If they come from a spin-0 particle, they'll have to have opposite spins, but... | [
"You have to be careful here: there's a difference between ",
" and ",
". Basically, \"spin\" is the ",
" of intrinsic angular momentum possessed by a particle, but \"spin state\" includes the amount ",
" the orientation. The amount is an innate characteristic of a particle, and it is the same for its antip... |
[
"What exactly moves through the nephrons in the kidneys?"
] | [
false
] | I understand the basic functions of the different parts of the nephron (glomerulus, Bowman's capsule, etc.), but I'm not too clear on what is moving through where, and my biology textbook is no help. For example, I know that the proximal tubule is responsible for active reabsorption of glucose and amino acids, but I do... | [
"Check out ",
"this section of the Wikipedia page on Bowman's capsule",
". The solution that passes into the proximal tubule is close in content to blood plasma.",
"So you can subtract whatever solute is removed through the journey to see what remains."
] | [
"To build a little off that, its close to plasma because the entire proximal tubule filters passively, so it relies entirely on solute potential. Since the distal tubule uses active transport, that is where the concentrating occurs."
] | [
"Well, as you know Red blood cells, white bloods cells cannot be filtered due to there size, through the main filter which is known as the BASEMENT MEMBRANE. Only small ions are able to pass through such as potasssium, calcium, water.",
"As you already know the functions of the Proximal convoluted tubule, what yo... |
[
"What if you dumped 1000 gallons of arsenic in the shipping canal?"
] | [
false
] | null | [
"Mathematics"
] | [
"Mathematics"
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"guidelines",
"/r/AskScience",
"If you disagree with this decision, please send a ",
"message to the moderators."
] |
[
"How do the resistors in this circuit not undo the gains of the voltage multiplier?"
] | [
false
] | Hello, I want to built . It's an air ionizer that uses a to up the voltage to 4kV. Now notice the big 9MΩ of resistors at the very end. I understand they're there for safety, in case someone touches it and closes the open circuit with their body, to limit the voltage. (Also, all the air ionizer circuits I see are for 2... | [
"This circuit will work just fine at 110V.",
"The purpose of the 9MΩ is to increase the source impedance. When the voltage is too low to arc through the air, no current flows through those resistors so there is no power loss there. When current does flow due to electrical breakdown of the air to ground, those res... | [
"(Also, all the air ionizer circuits I see are for 220V. What should I change so this circuit works on 110V?)",
"This circuit will works on 110V, but will generate half voltage, than it generated from 220V.\nIf you want to generate the same voltage, you can use step-up transformer, to step up 110V to 220V, or you... | [
"Thanks for the response! I'll likely use a transformer since I've read if you use too many diode-capacitor pairs it ",
"becomes counterproductive and starts decreasing the final voltage",
"."
] |
[
"What would happen if cold transferred like heat, and vice versa?"
] | [
false
] | null | [
"'Chemistry'"
] | [
"'Chemistry'"
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"It is hypothetical or speculative in nature. We do not allow hypothetical questions because questions that cannot be confidently answered with any available data often invite non-scientific speculation.... |
[
"If you use have a pair of headphones with wires 100 miles long, is there difference in audio quality versus typical length headphones? Why?"
] | [
false
] | [deleted] | [
"Equation used to calculate the data:",
"Ploss = 10 * Log [1 - ((2 * RL) / (2 * RL + (Vline squared / Prated))]",
"RL = (Rref / 1000) * D",
"Where:\nD = length of wire used",
"Ploss = power loss in dB\nPrated = power driven on line\nRL = wire guage resistance\nVline = voltage on line",
"At 100 feet using ... | [
"OP actually asked about ",
"! I think it would be noticeable!",
"Edit: typo (\"abot\") fixed (\"about\")."
] | [
"It would likely be a much higher loss than that. Over a distance like that the resistance of the wire would cause such a large voltage drop that random noise would be larger than the signal itself. You're looking at the 1-2 ohm per 100 feet range for the resistance, so over 100 miles, you would see something on ... |
[
"How come when I am having trouble recalling a name, I know the letter it starts with, or what it sounds like, but not the actual name?"
] | [
false
] | How come my brain can know fractions of information on something, but have trouble putting it all together? And what is happening in my brain when I suddenly remember the name? | [
"http://www.youtube.com/watch?v=CSf8i8bHIns",
" this video explains why around the end of the video."
] | [
"Your'e welcome Massiveboner911"
] | [
"That was a very interesting video. Thank you for sharing."
] |
[
"If you filled one swimming pool with golf balls and another with tennis balls would they both have an equal amount of empty space?"
] | [
false
] | Obviously not counting the space the tennis balls. Edit: Great answers and discussion but maybe i should clarify/simplify what I'm asking because there's far too many variables... Make the balls frictionless, incompressible, solid balls of two different sizes, stack them in the most efficient way possible and then take... | [
"Yes (with a negligible difference and insofar tennis balls are smooth spheres - ignoring the fuzz)",
"Close packing of equal spheres in an infinite volume reaches a occupied volume fraction of roughly 0.74.",
"On the borders of the swimming pool, you would have a bit more air, but as the swimming pool is much... | [
"I don't think close packing is really applicable. Probably something more like...\n",
"http://en.wikipedia.org/wiki/Random_close_pack"
] | [
"They would not have equal air space.",
"This question is something civil engineers deal with on a regular basis and the technical term is void volume. As the average size of aggregate decreases, the amount of void volume decreases. As the average size of aggregate increases, void volume increases.",
"A month a... |
[
"Will Jupiter's Red Spot separate into equal bits?"
] | [
false
] | I keep hearing that the Red Spot on Jupiter is falling apart with smaller red flaked storms spilling away, but how true is it? Is this just some kind of awe tactic or is it true? And second, if it is true would it be possible that Jupiters red spot separates into a few equal sized spots or something along those lines? ... | [
"I think the idea is that the weather systems keeping it so consistent over the few hundred years we've known about it aren't stable over longer periods than that, and based on our understanding of how vortices collapse, it's expected that it will separate into smaller vortices when it loses stability eventually. I... | [
"I think it's a perfectly valid question in light of click-baiting articles available online in this day and age. I've seen YouTube and other posts claiming evidence of alien life on Jupiter, Jupiter's imminent destruction, etc., so it's perfectly reasonable to be skeptical that articles about the dissolution of th... | [
"I think it's a perfectly valid question in light of click-baiting articles available online in this day and age. I've seen YouTube and other posts claiming evidence of alien life on Jupiter, Jupiter's imminent destruction, etc., so it's perfectly reasonable to be skeptical that articles about the dissolution of th... |
[
"Why are many common OTC pain relievers also fever reducers?"
] | [
false
] | [deleted] | [
"Basically, the way aspirin and ibuprofen works is by inhibiting a family of enzymes called 'COX' enzymes. This stops the formation of prostaglandins, which are compounds that are not only involved in pain, but also in temperature control. Paracetamol (acetaminophen) works in a similar way, but is thought to have o... | [
"It wouldn't really have an effect.",
"So basically, of the the prostaglandins, prostaglandin E2 has the biggest effect on 'fever'. One stimulus for its release is during an infection, where certain 'cytokines' produced by immune cells cause it to be released (think of these as signalling molecules). It then rais... | [
"It wouldn't really have an effect.",
"So basically, of the the prostaglandins, prostaglandin E2 has the biggest effect on 'fever'. One stimulus for its release is during an infection, where certain 'cytokines' produced by immune cells cause it to be released (think of these as signalling molecules). It then rais... |
[
"Why are nuetrons necessary?"
] | [
false
] | How do they physically play into the stability of an isotope? How do they stop protons from repelling each other? | [
"They don’t stop protons from repelling each other, they just provide binding energy due to their attractive strong interactions, without contributing any Coulomb repulsion."
] | [
"They don't provide an attractive electromagnetic force - i.e. they don't stop protons repelling each other.",
"A part of the strong nuclear force (another fundamental interaction like electromagnetism) which holds the quarks comprising individual hadrons (protons and neutrons) together kind of \"leaks out\" of t... | [
"To add to this, the residual strong force is kind of analoguous to how atoms have net zero electric charge, but if you get close enough you still get a lot of interesting electromagnetic interactions between electron clouds whereas the protons are confined to the comparatively tiny nucleus. Similarly, polar molecu... |
[
"If gravity propagates at the speed of light in a vacuum, and the speed of light through other mediums is lower than c... then can the speed at which gravity propagates also be slowed?"
] | [
false
] | RE: Not sure how else to phrase my question or if I'm doing a poor job. If light travels through other mediums at a lower speed than c, then does that mean gravity could also propagate at lower speeds than c? | [
"So gravitational waves ",
" have an index of refraction much like light does in say glass or water. Therefore, a gravitational wave can be slowed in a medium much like light does as well as refract and reflect. The effect is incredibly tiny for any realistic situation though and has not been measured.",
"See: ... | [
"Gravitational waves are self propagating waves of ripples in spacetime, much like light is a self propagating wave of ripples in the EM field. Just because you blocked the wave doesn't mean you don't feel sources on the other side.",
"In other words, you'll still feel the electric field caused by a charge or a g... | [
"Gravitational waves are self propagating waves of ripples in spacetime, much like light is a self propagating wave of ripples in the EM field. Just because you blocked the wave doesn't mean you don't feel sources on the other side.",
"In other words, you'll still feel the electric field caused by a charge or a g... |
[
"Is it likely that other animals will evolve to a point where they can communicate with humans through spoken language (English, French, etc,)?"
] | [
false
] | If this is likely, would type of animal would be the most likely? Cats and dogs because they live with humans and are more likely to adapt to speaking our language, or something like a chimpanzee because it's the closest living relatives humans have? How many generations would this likely take? I don't have any biolo... | [
"Some in the ape family have been known to learn sign language. That counts.",
"You don't need to speak English in order to communicate."
] | [
"Parrots."
] | [
"Thanks for the response, but I was wondering specifically about spoken language. "
] |
[
"Why are so many energy equations of the form E=(1/2)xy^2? Kinetic, elastic, heat, capacitor and inductor energy all have this form. Even E=mc^2 is almost there."
] | [
false
] | So as I've gone further into physics I keep seeing this pattern pop up. Many equations for energy have the form E=(1/2)xy That is half times a variable times another variable squared. Is there a reason for this pattern or just coincidence? I would have thought different forms of energy would have very different equatio... | [
"This is because energy is defined as integral of force (dot) dx. ([ ; (\\int F\\cdot dx) ; ] if you have latex).",
"If we look at some forces, we can derive the energy equations ourselves. Force due to a spring is F=-kx, k is just a number put there by humans so that our numbers would line up nicely with things ... | [
"They're almost all approximations. Most forms of energy we talk about are associated to small changes around some energy minimum. E=1/2 cx",
" is the simplest function that has a stable minimum at x=0, with energy increases to either side. So for small deviations from equilibrium it is convenient to ",
" the e... | [
"Why are forces linear then?",
"They aren't exactly. This is just a very useful and very close to accurate approximation for small perturbations. For example, springs don't actually obey F = -k x. If you stretch a string too far, you can make this approximation break down quite badly. I get the feeling you were a... |
[
"I typically like to refill an empty Gatorade bottle with water over and over again, however, I've had people tell me this is not a good idea. Are they right?"
] | [
false
] | [deleted] | [
"I've heard this before too. I feel it's a bit of a dubious claim but would like to know more.",
"If there is some chemical in the plastic that can be dissolved into the water contained in the bottle, wouldn't it make sense that the highest concentration of it would be in the first filling? If you reuse the bottl... | [
"Regardless of the actual dangers of BPA, what you describe is only true if the \"leeching out\" partitioning is not kinetically controlled. By that I mean you put your water in, and chemicals leech out quickly until equilibrium is reached. However, if the leeching out process is ",
" - so slow it won't reach equ... | [
"The claim is probably based off of something the claimant has heard about ",
"Bisphenol A",
"."
] |
[
"동탄오피〕 \"opopgirl01.com\" 〔의정부오피 오피오피걸 여자친구_시간을 달려서 ~광교오피"
] | [
false
] | null | [
"간석오피〕 \"opopgirl01.com\" 〔주안오피 오피오피걸 여자친구_시간을 달려서 ~인천오피간석오피〕 \"opopgirl01.com\" 〔주안오피 오피오피걸 여자친구_시간을 달려서 ~인천오피간석오피〕 \"opopgirl01.com\" 〔주안오피 오피오피걸 여자친구_시간을 달려서 ~인천오피간석오피〕 \"opopgirl01.com\" 〔주안오피 오피오피걸 여자친구_시간을 달려서 ~인천오피간석오피〕 \"opopgirl01.com\" 〔주안오피 오피오피걸 여자친구_시간을 달려서 ~인천오피"
] | [
"부평오피〕 \"opopgirl01.com\" 〔인천오피 오피오피걸 여자친구_시간을 달려서 ~삼산동오피부평오피〕 \"opopgirl01.com\" 〔인천오피 오피오피걸 여자친구_시간을 달려서 ~삼산동오피부평오피〕 \"opopgirl01.com\" 〔인천오피 오피오피걸 여자친구_시간을 달려서 ~삼산동오피부평오피〕 \"opopgirl01.com\" 〔인천오피 오피오피걸 여자친구_시간을 달려서 ~삼산동오피부평오피〕 \"opopgirl01.com\" 〔인천오피 오피오피걸 여자친구_시간을 달려서 ~삼산동오피부평오피〕 \"opopgirl01.com\" 〔인천오피 오피오피... | [
"천안오피〕 \"opopgirl01.com\" 〔당진오피 오피오피걸 여자친구_시간을 달려서 ~서산오피천안오피〕 \"opopgirl01.com\" 〔당진오피 오피오피걸 여자친구_시간을 달려서 ~서산오피천안오피〕 \"opopgirl01.com\" 〔당진오피 오피오피걸 여자친구_시간을 달려서 ~서산오피천안오피〕 \"opopgirl01.com\" 〔당진오피 오피오피걸 여자친구_시간을 달려서 ~서산오피천안오피〕 \"opopgirl01.com\" 〔당진오피 오피오피걸 여자친구_시간을 달려서 ~서산오피천안오피〕 \"opopgirl01.com\" 〔당진오피 오피오피걸 여자친... |
[
"Does the type of alcohol drunk, influence the type of drunken behaviour seen in the individual who drank it?"
] | [
false
] | null | [
"Not chemically. Any altered reactions to different forms of alcoholic beverages are psychosomatic or allergenic.",
"edit: I should be more clear. Different types of alcoholic beverages ",
" contain highly diverse arrays of ingredients and byproducts such as sulfites, various congeners, and additives that ",
... | [
"I'm inclined to think that ethanol is ethanol, no matter what the source is. But it could be possible that other proteins, sugars, acids etc. found in a particular source of alcohol could effect your mindset and/or behavior."
] | [
"Obviously if you drink more alcohol faster then you'll have an increased reaction. That's behavioral though, not an actual result of the drink. The same amount of alcohol is the same amount of alcohol whether it is delivered in beer or whiskey."
] |
[
"What causes leg cramps?"
] | [
false
] | null | [
"Sometimes dehydration and lactic acid build-up can cause these cramps. Try drinking lots of water and staying hydrated and see if you start to feel better. "
] | [
"Don't be a dick, this is was askscience is for"
] | [
"Don't be a dick, this is was askscience is for"
] |
[
"What is the Science behind the NFL's policy of adjusting medical diagnosis by racial factors when determining insurance payouts for concussion injuries?"
] | [
false
] | null | [
"Yes, recent research has continued to confirm that race is a significant factor in determining performance on standard neuropsychological tests, including those used to determine neuropsychological disability.",
"The introduction to this 2011 article summarizes the state of research at that time",
" with refer... | [
"If your test gives a quantified value, you can calibrate the test separately for each group. It's like how \"above average height\" is different for men and women because the average is different."
] | [
"I understand what this excerpt is saying, and I’m following the stats, but how does one correct for race? Is it using different testing criteria (i.e. physiological signs instead of a speech clarity test)?",
"If one group of similarly situated people (age, sex, education, etc.) who are white have an average scor... |
[
"What do we know about the last common ancestor of mammals and birds and when did it supposably live?"
] | [
false
] | null | [
"It's actually surprisingly far back. Mammals come from the ",
"Synapsid",
" Class of the amniotes, and birds are dinosaurs, so they'd have come through the ",
"Sauropsida",
" Class. Wiki has the ancestral synapsid at ~324 Million years ago during the late carboniferous. The permian, and most of the triassi... | [
"to illustrate shavera's answer a bit here are some links with nice illustrations of the vertebrate phylogenic tree:",
"http://scienceblogs.com/evolgen/2006/09/phylogeny_friday_22_september.php",
"http://rst.gsfc.nasa.gov/Sect20/A12d.html",
" (you'll have to scroll through a bit on this one)"
] | [
"Dimetrodon: I've heard that the giant sail may have served to control its body temperature. I would think it was probably living in warm areas and the sail helped to radiate temperature away.",
"and just to get a bit more off topic here two pictures of an arctic and a desert fox:\n(note the big ears on the deser... |
[
"Say there were two protons in some distant section of our universe so that all other gravitational attraction negligible. How far away would they have to be and how long would it take for their gravitational collision to result in a 50% chance of nuclear fusion?"
] | [
false
] | It seems like the protons would start towards each other as they were attracted by each other's’ gravity. It also seems like they would continue accelerating until they collided. And I understand that a two really fast moving protons (like in the sun) can overcome the electromagnetic repulsion can fuse together. I’d... | [
"If you are talking about protons only, then they would fly apart, regardless. They both carry positive charge, and the electromagnetic force is many orders of magnitude bigger than the gravitational force:",
"F_grav/F_Coul = -G * 4 * pi * epsilon0 * (m/q)",
"m/q for a proton is ~ 10",
" kg/C, G * epsilon0 * ... | [
"OP's asking how much those protons need to be separated, assuming they are the only things in the universe, for them to reach the required 0.035c, collide and fuse.",
"If they start from rest, they will never do so. As stated in the top-level comment, the electrostatic force between them is always repulsive and ... | [
"No, That is correct, but in order to tunnel they stll have to be within a few fm of each other, so we are talking similar orders of magnitude. The \"touching distance\" simply gave me a good starting point to plug numbers in."
] |
[
"Does the aphelion of the Earth orbit the sun?"
] | [
false
] | I was looking at and realized that aphelion of its orbit (the point farthest from its center of orbit) traces a circle as the object completes each orbit. Does the Earth also orbit the Sun in this way? By extension, does the Moon orbit the Earth in this manner? | [
"Yes, mostly due to the influence of Jupiter. The aphelion rotates relative to the seasons over about 21000 years."
] | [
"This video is quite good: ",
"https://www.youtube.com/watch?v=82p-DYgGFjI"
] | [
"It's funny, it's often quoted that Einstein figured out the anomalous precession of Mercury, which was 43 arc seconds per century. What is not often quoted is that the non-anomalous precession due to the other planets was already understood, which was about 530 arc-seconds/century."
] |
[
"How does human body convert energy to work?"
] | [
false
] | I am familiar with how we get energy from food then how is this energy converted to muscular work and also to electricity(electrical signals by brain) | [
"Muscles:",
"Your muscles are made up of giant bundles of teeny tiny fibers, one of which is ",
" very similar to the \"micro-tubules\" (actin filaments) which cover the inside of all cells like a highway.",
"These fibers are strung like cables parallel to each other, with a \"lever arm\" in between them. At... | [
"Via cellular respiration.",
"The body takes glucose and oxygen, releasing CO2 water and energy, which is stored in ATP(Adenosine Triphosphate) molecules. ",
"Wherever energy is needed in the body, ATP breaks into ADP(Adenosine Diphosphate), releasing the stored energy."
] | [
"Your muscles are made up of giant bundles of teeny tiny fibers, one of which is the same as the \"micro-tubules\" (actin filaments) which cover the inside of all cells like a highway.",
"A small note to your otherwise very good explanation: Microtubules are a separate type of intracellular filament, which serves... |
[
"Is there a real life analog for Iocane powder, from the Princess Bride?"
] | [
false
] | That is, is there a poison that is odorless, colorless, which dissolves instantly in water and causes immediate (or near immediate, with just enough time for an ironic one-liner) death with a dosage that appeared to be roughly a teaspoon, but can have an immunity built up against it? | [
"There are plenty of poisons that can kill with way less than a teaspoon and can cause near immediate death. The hard part of your question is the second part where a natural immunity can be built up to it. "
] | [
"is it just happen stance that you posted almost an identical question to ",
"this",
" about 6 hours afterwards?"
] | [
"It's a follow-up to that thread that I figured I'd put in a new thread"
] |
[
"If I were to plant a tree in zero gravity what way would it grow?"
] | [
false
] | On Earth most trees grow up, what would happen without gravity? | [
"Plants grow towards source of photons and root away from source of light. They do the same thing in zero g (it's been tested on the ISS). The exact pattern of roots and leaves, however, is partly determined by gravity. ",
"So, in short, it depends on how you light them, but as long as your lighting is not unifor... | [
"You are wrong. Like I said, ",
"this has been tested on the ISS, and the primary determinant of root direction is light, not gravity",
". "
] | [
"You are wrong. Like I said, ",
"this has been tested on the ISS, and the primary determinant of root direction is light, not gravity",
". "
] |
[
"How do species mate when they evolve to have different amount of chromosomes?"
] | [
false
] | Say generation Y had chromosomes, and a single offspring had Y+1, how does that offspring mate with other non-mutated offspring from its generation? As far as I understand, two species with different amounts of chromosomes cannot reproduce. For example, humans have 23 pairs of chromosomes. Other primates/mammals with w... | [
"It's not strictly that the different numbers of chromosomes between species is the cause of dysfunction, it's more that what each chromosome codes for in species can MASSIVELY vary. If you get a mix of chromosomes whose activity interferes with each other (or a chromosome that codes for something but the regulatio... | [
"Female mules sometimes give just the genes from their mothers. When they produce foals, it's not really any different than horses and donkeys mating. They have one copy of each chromosome from each parent, so they have all the genes they need. But it's a dead end, and taking half of those at random won't work."
] | [
"Donkeys and horses have a different number of chromosomes but they can mate! They can produce offspring (the mule). In most cases their offspring are sterile but there have been very rare cases when mules have produced foals!"
] |
[
"Why does this reaction occur?"
] | [
false
] | In this reaction: 2Li + 2HNO3 --> H2 + 2LiNO3 the lithium replaces the hydrogen. NO3 has a higher standard reduction potential so why is the hydrogen replaced? | [
"G = H - TdS",
"G is the Gibbs free energy: the absolute energy in the system. H is the enthalpy, or energy contributed by bond cleavage and formation. T is temperature. S is entropy, the energy contributed by the 'disorder' of the system. The more negative the Gibbs free energy, the more favourable the react... | [
"Thermodynamically, it would be more stable if nitrate oxidized the lithium metal to make nitrite or nitric oxide, but protons can attack the lithium and accept its electrons much faster. The main reason is that the reduction of nitrite requires breaking a fairly strong N-O bond, while no bonds need to be broken w... | [
"First, recognize that there are electrons moving in this reaction. Lithium metal is a reducing agent, while Nitric Acid is an oxidizing agent. Lithium is oxidized (loss of e-) from neutral metal, oxidation state of 0 to +1 in Li+. Also, NOx is liberated as the oxidation state on Nitrogen changes.",
"Lithium is i... |
[
"Are there any good books or documentaries on abiogenesis?"
] | [
false
] | Preferably documentaries that would show how the first molecule-nucleotide-protein-cell-complex organism formed in detail. | [
"Abiogenesis",
" by cdk007 on Youtube. ",
"The best explanation of the leading abiogenesis hypothesis I've seen. 10 minutes long, give or take. "
] | [
"I met Jack Szostak last week!"
] | [
"Genesis by Robert Hazen",
" is excellent."
] |
[
"Is dark energy in any way related to the inflation that took place in the early universe or are they completely different processes?"
] | [
false
] | Basically the title. I want to know what part, if any, dark energy played in the inflation of the universe. | [
"Dark energy is thought to be a (positive) ",
"Cosmological constant",
", this is a constant added to the field equations of general relativity. The positive sign of the constant means that it acts like an 'anti-gravity' term that pushes everything away from everything else.",
"The physical meaning of a posit... | [
"The thing is that the expansion is accelerating. This requires some sort of energy to explain, whether it's a cosmological constant or quintessence."
] | [
"Conservation of energy only holds in systems that have ",
"time translation symmetry",
". If the laws of physics change with respect to an \"absolute time\" in the universe - which is possible - then energy does not need to be conserved for the whole universe."
] |
[
"Why does an accretion disc fall into a black hole instead of orbiting like saturn's rings?"
] | [
false
] | Is it something go do with Saturn's moons keeping the rings stable? Or maybe because the discs are made of mostly gas rather than bits of rock and ice? | [
"Imagine two rings of dust or gas, orbiting completely circulars round a black hole, and very close to each other. Because the gravity of the black hole is so strong, the rings will be orbiting at very high speeds, but the inner ring significantly faster. If any particles (solid, liquid or gas) in the two separate ... | [
"Because black hole accretion disks are hot and therefore have a great deal of plasma, there are also magnetohydrodynamic effects which can cause exchange of angular momentum within the disk and cause material to drift inward. Last year, the Shaw Prize (the biggest prize in astronomy) ",
"was awarded to Stephen B... | [
"I believe the best current understanding is that Saturn's rings aren't stable. For example, the E ring is being supplied material from Saturn's moon Enceladus. So even in that context, they are technically falling inward as well, at some rate."
] |
[
"How can you \"dye\" oil (while having it in the same container as water) and not have the bleed effect?"
] | [
false
] | I've been trying to figure out how to legally ship a bottle with two different colored liquids (of two different densities). I've failed at both. I want the top liquid to be "dyed" a different color while the bottom liquid remains clear. I found that alcohol floats on oil and when dyed, doesn't bleed. However, shipping... | [
"What dye are you using?"
] | [
"I've used a candy \"dye\" in the oil. I was told it was great for coloring oils because it uses glycerin and is not water soluble. Well, after letting the colored oil sit on top of the water in the bottle, the color bled into the water and changed it too. So, apparently it is water soluble. :/"
] | [
"http://en.wikipedia.org/wiki/Dye#Dye_types",
"Apparently some dyes that aren't soluble in water can react with alcohols to form dyes that are soluble in water.",
"You might try using a ",
"solvent dye",
", but I recommend checking that whatever dye you choose won't react with whatever solvent you use.",
... |
[
"How does a lazy eye affect vision?"
] | [
false
] | Can somebody with a severe lazy eye actually see out of that eye? Are they constantly looking in two places at once, or is it just the healthy eye that can see? If they are looking in two places, how does that affect their visual field? | [
"If you are referring to strabismus (as stuthulhu explained) combined with amblyopia, it directly impacts the perception of depth of field. Since the images from both eyes fuse thanks to the brain, and thus create \"3D\", the misalignment of one eye, and/or the fact that the brain takes only one eye into account up... | [
"A point of clarification, \"lazy eye\" often refers to Amblyopia, which is a condition where vision is impaired in an eye without/in excess of actual structural abnormalities. The brain effectively ignores input from that eye to some degree. It does not necessarily imply that eyes fail to 'track' together.",
"St... | [
"This is just a reminder that answers need to contain scientific knowledge that's backed by peer-reviewed research. Personal experiences or anecdotes are not appropriate. Thank you very much!"
] |
[
"Is there any reason to rule out the possibility of multiple universes separated by distance?"
] | [
false
] | Similarly to how we have multiple galaxies separated by distance. Obviously, it's impossible to actually verify, but is there any reason to believe that there do not exist other universes some unknown distance away from the edge of our observable universe? I suppose, for the sake of discussion, I'm defining "universe" ... | [
"It is my belief that the hardest thing about proving or disproving this is that we have no concept to define what is not in our universe, therefore, we cannot say there is or is not \"space\" in between our universe and a parallel one."
] | [
"Think of all of spacetime as one ball. This is what we call a connected manifold. Now imagine two disjoint manifolds. That is an example of a disconnected manifold. Roughly, there are pairs of points that cannot be connected by any path. For example a point in one ball cannot be joined to a point in the other ball... | [
"There are such galaxies outside of each other's cosmic event horizon. They are both still part of the same universe. "
] |
[
"Is it scientifically feasible to implant life on a nearby planet or moon?"
] | [
false
] | Could we breed a species of microorganism, or otherwise genetically modify it, so that it may survive in the conditions of an extraterrestrial environment, and then implant it in said environment? Has there been much talk of this in the scientific community? Would there be any benefits from doing this other than provin... | [
"But wouldn't terraforming be the opposite of what I described? "
] | [
"I think so, terraforming is to modify an environment so that organisms can live there. You're asking about modifying the organism to survive in a currently hostile environment?"
] | [
"I think the scientific case would be to ",
" a hypothesis that the organisms could terraform the planet. ",
"Yes, some candidate organisms have already been picked out for mars and Venus",
". If there ",
" life on Mars, it might be destroyed by alien life forms from Earth. ",
"The ",
" case would pr... |
[
"Do giraffes vomit?"
] | [
false
] | null | [
"Someone's been reading showerthoughts this morning ;)",
"Yes, they do. There are even videos of them doing it on Youtube if you're so inclined.",
"They also regurgitate their cuds to chew them like cows do, but that's a bit different from what we humans think of when we think \"vomit.\""
] | [
"Giraffes are ",
"foregut fermenters",
" and ruminants, therefore regurgitation is a necessary part of digestion. Horses, rabbits, and some rodents, however can not vomit, or at least it's very difficult for them to. A sphincter muscle that separates the esophagus from the stomach is responsible for the ability... | [
"Inversely, most ant poisons are designed around the ability of ants to regurgitate in their nests."
] |
[
"What would the state of water be at the bottom of a 160km deep ocean?"
] | [
false
] | I've read that Europa possibly has oceans up to 160km deep under it's surface, so obviously there will be a bit of pressure build up as you descend. However, Europa only has ~one hundredth of Earth's mass, so, perhaps naively, I reckon that this would be equivalent to the pressure 1.6 km of depth in terrestrial water.... | [
"This is not correct. That calculation assumes Earth surface gravity. Pressure depends on the strength of the gravitational field. ",
"The surface gravity at Europa's equator is only 0.134g. ",
"You would need to reduce the calculation by the difference between the gravitational accelerations.",
"To make thin... | [
"Phase Diagram of water",
"160km of water is about 1.5 GPa",
" of pressure, ignoring the atmospheric pressure at the surface of the water and the temperature. ",
"I am bad at reading logarithmic scales but I am going to try and say at 1.5GPa water will freeze at 330 K which is ",
"+56 degrees celcius",
".... | [
"I assumed I was missing something thanks. But OP can figure out whatever pressure s/he wants and can use that phase diagram. "
] |
[
"In the densest parts of galaxies, how close can stars get to one another?"
] | [
false
] | null | [
"Although a pretty rare event, they can ",
"collide",
", or in other words, they can get arbitrarily close. ",
"The densest regions are the galactic nuclei as well as the cores of globular clusters, in which you can have thousands of stars per cubic parsec. The core of M 32, a satellite galaxy of the Andromed... | [
"So compared to that are we in a dense spot or not? ",
"No, not even close. In one cubic parsec of space with the sun at the center, we would have exactly 1 star occupying that space - the sun itself. The next closest star is about 4,24 lightyears away, which equals 1.3 parsecs or 40113 billion kilometers."
] | [
"So compared to that are we in a dense spot or not?"
] |
[
"Why Does The Sun's Path In The Sky Change Through The Year?"
] | [
false
] | I've noticed now that my walk to and from the train station at work is directly East and West that during the year, the sun rises and sets at slightly different locations in the sky. During May and August (or thereabouts), the Sun would be directly east and west (and in my eyes) in the morning and evening. What's the r... | [
"Axial tilt!",
"So the Earth spins around, but it doesn't just spin straight up and down, it spins at an axial tilt, ",
"shown here in this photo",
" of about 23 degrees. But in addition to that it rotates around the sun. As it rotates sometimes the northern hemisphere (the top half of the globe with USA, Ger... | [
"A great answer, thank you!",
"Do we know if this pattern has been fairly regular throughout Earth's history?"
] | [
"The spin of the Earth is tilted in relation to it's orbital plane around the sun. As it orbits the sun over the course of a year, different parts of the Earth are facing directly at the sun. This means that as the Earth rotates, the sun will appear to rise and set in different spots. This is also what causes the c... |
[
"Why doesn't the strong nuclear force diminish by the inverse square law?"
] | [
false
] | I read the wikipedia article, but it was way over my head... | [
"This is a very important subject known as \"quark confinement\" or more generally \"confinement in gauge field theories.\" ",
"Electrodynamics and chromodynamics (strong nuclear force) are both Yang-Mills gauge theories. \"Gauge\" means locally invariant under symmetry transformations from a compact Lie grou... | [
"because its influence spreads in 3 dimensional space?"
] | [
"To this already awesome explanation just wanna add this question I asked a while ago about gauage theory to give people more information ",
"http://www.reddit.com/r/askscience/comments/sn909/eli_a_moderately_intelligent_adult_gauge_theory/"
] |
[
"What makes \"the birthday paradox\" a paradox?"
] | [
false
] | Just because it has a result you don't expect doesn't make it a paradox, right? Am I missing something? | [
"This is purely an issue of semantics. Indeed, it is not paradoxical in the technical sense, that is, it is not a logical contradiction. However, people often colloquially use the word \"paradox\" to mean \"something that is counterintuitive\" or \"something that appears to be a contradiction at first glance.\" The... | [
"FYI: Birthday paradox is that you only need 23 to have a 50% chance to have 2 people with the same birthday. (and 70 people gives you 99.9% probability). That's counter intuitive. 23 people with 365 possibilities giving 50%"
] | [
"FYI: Birthday paradox is that you only need 23 to have a 50% chance to have 2 people with the same birthday. (and 70 people gives you 99.9% probability). That's counter intuitive. 23 people with 365 possibilities giving 50%"
] |
[
"Why do metals spontaneously fuse together at a very low pressure? What mechanism of physics enables \"cold welding\"?"
] | [
false
] | I ran across and was fascinated that metals could be coaxed into bonding together by nothing other than low pressure and a bit of force. This seems very strange given our everyday reality of metals not fusing when brought into contact. What mechanism enables "cold welding" (or "vacuum fusion")? | [
"It's not so much that the vacuum causes it; rather it's that the oxygen in the air prevents it. It forms a thin oxide layer that prevents metals from bonding. In other words, they bond with the oxygen instead of each other. When you take away the air, and therefore the oxygen, the metals are able to bond with e... | [
"If you have two sheets of the same metal, in atmosphere, oxygen will bond with the metal forming a very thin oxide layer. This oxide layer is pretty stable, so it won't spontaneously bond to the oxide layer on the other sheet.",
"Now, if you remove the atmosphere and remove the oxide layers, you will just have t... | [
"What would happen if you removed the oxide layer in a pure nitrogen environment? Is the low pressure just as important as the lack of oxygen?"
] |
[
"Audio engineers...do cables really matter?"
] | [
false
] | I've heard countless arguments on cables and whether or not they affect the end (digital) product. Does it matter, or can I really use coat hangers? | [
"When you're wiring your home surround system, no, pretty much not at all. But over long distances like on a concert where some cables run several tenths of meters, sometimes even a hundred meters, the resistance and interference has to be reduced, or else you're going to end up with artifacts and noise. "
] | [
"Actually, it increases the inductance (coil == inductor != resistor), which increases the ",
" at higher frequencies, turning the cable into a low pass filter (or, strictly speaking, it lowers the cutoff frequency, since all wires have some self inductance)."
] | [
"Also check that the lamp and plug are detached from the cable before use."
] |
[
"How does flash memory store data even when no voltage is applied?"
] | [
false
] | null | [
"FLASH memory is basically just a lot of transistors which are toggled on or off. If a transistor is toggled on, that might be considered a logic '1' and if it is off it would then be considered a logic '0' (there is also the possibility of encoding more data by putting the transistors in states between on or off, ... | [
"I think this answer can be more specific.",
"Ok, so in an ideal mosfet, they in fact could all work like flash because the gate forms a capacitor. However, this capacitor is non-ideal. If you apply a voltage signal to a real mosfet and then stop, in fact the gate will stay on until the leftover charge leaks out ... | [
"If I recall correctly, it is not actually an acronym. Instead, it comes from the early history of the technology, when the memory was cleared blockwise like it was hit by a flash of lightning."
] |
[
"How intelligent are parrots?"
] | [
false
] | Can they answer yes/no questions? Can they form opinions or make statements based on their environment? Or do they just react with words to what we say and not actually think any thoughts. | [
"It's somewhat controversial, but there's ",
"evidence that African Grey Parrots can exhibit fairly advanced cognitive functions, on par with some primates.",
"Another ",
"example here",
".",
"The extent of their intellectual ability hasn't been fully explored yet, but the evidence seems to suggest that t... | [
"I've seen a lot of these comments recently. They don't make much sense.",
"When questions like these come along, I would expect the experts in the field to explain that as part of the question. If a layman asks, you can't expect them to know about traits between several types of parrots, otherwise they would pro... | [
"I've seen a lot of these comments recently. They don't make much sense.",
"When questions like these come along, I would expect the experts in the field to explain that as part of the question. If a layman asks, you can't expect them to know about traits between several types of parrots, otherwise they would pro... |
[
"Are Lorentz transformations equivalent to linear scaling an object rotated 45º? [images included]"
] | [
false
] | One of the best videos that helped me understand relativity (before askscience existed) was this one: . What I had intuitively understood was that if we imagine we could by simply But if we switched it for two spaceships flying at 0.5c in opposite directions communicating with radio waves the transformations would be d... | [
"No, they're not.",
"The Lorentz transformations are the set of all transformations that leave the ",
" invariant. The Minkowski interval of a vector is the inner product of that four-vector with its dual, and the dual of a four-vector is the inner product of that four-vector with the Minkowski metric.",
"Whe... | [
"A property of a proper rotation in 3D is that it keeps the distance between two points constant: infinitesimally, you can say that ",
"² + ",
"² + ",
"² is constant.",
"A Lorentz boost keeps ",
"² + ",
"² + ",
"² – (",
" ",
")² constant. The difference between time and space is illustrated in the... | [
"You may be interested in ",
"Minkowski diagrams.",
" For a lot of qualitative work in special relativity, these are great go-to things to work with. They're just hard to do here, on this forum."
] |
[
"How far away are we from ocular implants? (tiny cameras in our eye-sockets?)"
] | [
false
] | My vision is slowly going. Good thing my glasses still work alright. And instead of LASIK someday, I'd rather wear ocular implants that can also zoom in and out, record video, see infrared (and other visual frequencies) and do much more than original 20/20 eyes can. So how is the development of ocular implants coming a... | [
"We might be closer to the opposite approach, decoding the images from an organic eye into a digital output.",
"https://www.washingtonpost.com/archive/politics/1995/07/10/horseshoe-crabs-eyes-offer-insight-into-human-vision/488f06dc-585c-4709-8d67-4355eeff5aa3/?utm_term=.0a08be85032e"
] | [
"My eyes suck so I'd definitely sign on for like 4k camera eyes or something. Hell could we pay extra and stick night vision or x ray on em? Like yes it sounds scifi but we already have smallish cameras so theoretically don't we need some way of powering the camera and transcribing what the cameras see and turning ... | [
"Interesting read thanks."
] |
[
"What does a Newton (force) mean?"
] | [
false
] | Specifically I am talking about the units (Kg x m)/s I am having trouble conceptualizing it. I can conceptualize m/s because its how many meters you go in one second. m/s also makes sense because its how many meters per second you change every second (acceleration). I cannot conceptualize what a Kg x m is much less a K... | [
"It's the force required to uniformly accelerate a one kilogram object to one meter per second over the course of one second."
] | [
"You can't just look at the dimensions that compose it. It won't make sense that way. A watt is a rate of change in energy of one joule per second."
] | [
"These sorts of things are easiest if you \"chunk\" them up, into different units that make sense. So, a Newton is a kg*m/s",
" which we can break up into (kg)*(m/s",
" ) which is (mass)*(acceleration). We can recognize a mass times an acceleration as a force. Does it make sense?",
"Let's think of it like thi... |
[
"Why do we forget our dreams so quickly?"
] | [
false
] | I woke up this morning with one of the strangest, weirdest dreams that I think involved government conspiracy, murder, and minigolf courses. I know there were details that somehow put those together, but only moments after I woke up, everything started to fade. I don't really remember much of it any more. How does this... | [
"The neurochemical content of your brain is different. During slow wave sleep, you have low levels of acetylcholine and noradrenaline. During REM acetylcholine levels are higher but noradrenaline levels are floored. Your brain is not capable of plasticity in the same way as it is when you are awake (note: the brai... | [
"And if you don't write down anything, there is no way for the brain to access that information. There is no logical path in the real world that would link the conspiracy with the murder on a golf course, so the memory is stuck on some island that you can't get to.",
"I sometimes feel similar when coming up with ... | [
"If you quickly write down as much as you can after waking up, it's easier to remember your dreams in surprising details later on.",
"I've been doing this for a while. I can read notes that are years old, and remember them as if it's something I've experienced in real life. Doing this exercise for a while makes... |
[
"How can a star emit enough photons for its light to be seen in all directions billions of light years away?"
] | [
false
] | Assuming light from a star can be seen billions of light years away in all directions, you can envision a sphere with a diameter of a few billion light years. Photons would have to basically cover the entire surface area of the sphere right? Seems like an impossibly large amount of photons. How does this work? | [
" Because photons carry an abyssmally small amount of energy, so there are a shit ton of them. ",
" Consider the sun. ",
"The sun's puts out 384.6 YW. Those units are \"yottaWatts,\" or 10",
" Watts. This is a very funny unit that for some reason reminds me of ",
"Watto,",
" the flying junkyard neckbeard ... | [
"Isn't this also the reason for long exposure times? If a surface is receiving 10,000 photons per second, you can increase the detail and clarity of a picture by having exposures measured in minutes or hours or even days if you have a stable enough camera (like the Hubble)."
] | [
"That's a bingo."
] |
[
"Why does sperm light up under blacklight?"
] | [
false
] | null | [
"Many bodily fluids, including semen, have compounds in them called phosphors. When exposed to the high energy photons of UV light, the phosphors in the fluid light up. \nThe process by which this happens is the energy from the light excites the electrons in the phosphors to a higher energy level. When the electron... | [
"I can answer \"Why do ",
" light up under blacklight?\" Someone else will have to answer why sperm is one of those things.",
"When you shine light of a particular frequency on an object, usually it will emit the same frequency back at you -- green light shone on a typical wall will appear green because it refl... | [
"Phosphate groups are essential to life. They are part of the ATP molecule, the energy source of most cellular functions. ATP has three phosphate groups, by breaking the bond between the second and third, the cell gets energy. Phosphate groups are used for energy, the glow in the dark function is just a coincidence... |
[
"Is the human body actually better suited for two four hour periods of sleep than one eight our period? (cross post from r/answers)"
] | [
false
] | I've seen/heard this many times before, but could not find any study or research that affirms this. ( ) | [
"Hey look, an anthropology question! Hooray!",
"One of the few people to do studies on the anthropology of sleep is Carol Worthman. Her research shows wide changes in sleep patterns across cultures, which suggest that biphasic sleep is not biologically \"set\". In other words - not everyone sleeps like we slee... | [
"So in reference to the OP's question, we are not sure?"
] | [
"I don't know what to make of that paper.",
"From neuroscience/behavioral studies and animal models we know that an 8 hour sleep period (actually, a single sleep period of at least 6 or so) hours are better than bi- or poly-phasic sleep.",
"Part of the reason is because of the alternating slow-wave (body awake/... |
[
"When ignited what temperature does gunpowder reach?"
] | [
false
] | The various sources I've found provide conflicting information, and I'd genuinely like to know the truth of the matter. Also, on a slightly related note, what would be the 'blast radius' of a barrel of gunpowder being detonated? How about the blast radius of 10 square feet worth of it? | [
"It depends on the conditions. Gunpowder works by turning a solid into gas and releasing energy in the process. Since the temperature is high, these gasses may be modeled by the familiar Ideal Gas Law, which is given by ",
"PV = nRT ",
"Where P is pressure, V is the volume the gas takes up, n is the number of ... | [
"I see! And this would determine the detonation size as well, then?"
] | [
"Gun powder (classic type) generally does not detonate. You don't want it to. Detonation would damage the metal chamber and barrel. It ",
"deflagrates",
", a sub-sonic combustion. ",
"Detonation",
" is supersonic combustion. Even modern smokeless powders are not made to detonate.",
"I all cases the peak p... |
[
"How many of the stars visible to the naked eye are actually stars? In everyphoto of space, through a telescope, I see thousands of galaxies."
] | [
false
] | [deleted] | [
"All of them. You can only easily see four galaxies with the naked eye (Milky Way, Andromeda, Magellanic Clouds), and none of them look like stars; all are fuzzy patches of different size."
] | [
"Keep in mind that such questions usually come from interested beginners. He may have asked for galaxies, but there are also planets which almost look like stars and therefore can't be differentiated as easily for someone who just have started in astronomy. So a better answer would be, that almost all stars are ac... | [
"Keep in mind that most of the photos that have that many galaxies in one image are Hubble images, usually deep field images. To see them at all required an exposure time of over a week.",
"The stars you see in then night sky are actually stars (or planets, in a few cases), and all of them are in our galaxy. Gala... |
[
"How long do immunoglobin molecules last in the blood and are they being continuously created?"
] | [
false
] | I was discussing this with a friend - it's been a few years since our immunology class and I couldn't find the answer in a book. I know that after a person gets a hepatitis B vaccine, they develop immunity as anti-Hbs immunoglobulins. I'm guessing B cells which bind to antigens in the vaccine become plasma cells and me... | [
"Ig are temporary, memory cells last semi-permanently but have lower basal activity unless stimulated by their associated antigen. so 10 years post vaccine those Ig are long gone. ",
"Exposure to antigen rapidly activates memory cells (no recombination or class switching this was already done) causing rapid inc... | [
"Immunoglobulin molecules have short half-lives: ",
"Up to about 20 days in serum for IgG",
".",
"Since antibody-based immunity lasts much longer than that, it means that new immunoglobulin is being constantly produced to (nearly) replace the fraction that's lost.",
"Antibody levels do fade over time, as me... | [
"New-borns have substantial passive immunity from immunoglobulins that they got from their mothers in utero for weeks to months, even when exclusively formula-fed. ",
"\"IgG is the main antibody in serum. The IgG class is the most stable and has a serum half-life of 20 days, whereas IgM and IgA persist for only 5... |
[
"Will we ever get rapid at home flu and cold antigen tests?"
] | [
false
] | null | [
"Part of the problem is what are you testing for? Colds can be caused by many different species of Coronavirus, Rhinovirus, RSV, and Parainfluenza, as detailed ",
"here",
". Most of the time when people say they have \"the flu\", it's actually what we would normally call a cold, not the actual Influenza virus. ... | [
"Pretty sure that’s not a home kit, or at least isn’t approved for home use. It’s a rapid diagnostic test aimed for use by medical professionals in their office, not by home users. Note the line “This product is only allowed to a Medical Professional” in the info. Such tests have been available for years, but that’... | [
"And also, ",
"you ",
" buy influenza home tests",
", just like you can get covid or strep tests."
] |
[
"Why are large physics detectors like LHC and Super K buried underground? Is it because they are dangerous?"
] | [
false
] | null | [
"I can only answer this question for the LHC, but the main reason is simply that the device is too big to economically build above ground.",
"The LHC reuses the tunnel previously used for the LEP (Large Electron-Positron collider). It has a diameter of 27 km and building such a large structure above ground would ... | [
"https://cms-safety.web.cern.ch/images/SAF/plan_general_11_2010.jpg",
"The areas shaded yellow and orange are owned by CERN. The tunnels on the Swiss side just needed federal approval. On the French side would have needed approval from each individual landowner, but a law was passed so that \"only\" each commune ... | [
"So they tunneled under land that CERN doesn't own? I had no idea. I imagined that they dug a trench and then filled it back in. I also had no idea it was as deep as 100m! "
] |
[
"How will the alpha-centauri nanoprobes handle the enormous amounts of acceleration to get to 20% the speed of light in a matter of minutes?"
] | [
false
] | According to the nanoprobes that Hawking just announced that are to be sent to Alpha Centauri will be accelerated to .2c in just a matter of minutes. Back of the envelope calculations show that this will require something on the order of 1000g or more sustained acceleration for those minutes. How can those probes be ma... | [
"I know absolutely nothing about nanoprobes so someone else should speak to their structural integrity, but I have done some work on larger objects with really massive accelerations. My hypersonics professor worked on the ",
"Nike missile projects",
" where the 7700 pound Sprint missile accelerated at 100g - Ma... | [
"Yes it is. In structural engineering N/m",
" or Pa is used to express tension in and on structures."
] | [
"Yes it is. In structural engineering N/m",
" or Pa is used to express tension in and on structures."
] |
[
"What is the difference between the Particle Horizon (which, according to Wikipedia, is the \"boundary between the Observable and Unobservable Universe) and the Cosmological Event Horizon (16 billion light years away)?"
] | [
false
] | [deleted] | [
"The particle horizon is at the distance beyond which light emitted at the big bang has not yet reached us. The cosmological event horizon is at the distance beyond which light emitted ",
" will never reach us.",
"For more you can see ",
"this thread",
" where I explain everything in all their gory details.... | [
"The Hubble sphere and the cosmic event horizon are not generally the same. (They coincide only if the Hubble parameter is constant in time.) The Hubble sphere is defined as the distance at which the recessional velocity is equal to ",
". This should not be interpreted as or described as \"the distance at which s... | [
"Thanks for the reply. That makes alot more sense.",
"So to summarize my understanding of space's limits and horizons, I drew ",
"this",
" diagram and the only thing I think I'm missing is the Hubble Sphere. I think I understand what this Sphere is. It's a radius that is growing larger because of the expansio... |
[
"Why are nose bleeds relatively painless, when other similar wounds on the skin are painful?"
] | [
false
] | null | [
"OP, nose bleeds are caused by injuries from an internal source of your body. When you get a cut on your arm, leg, etc., there are nerves built to transmit pain to your brain - and these nerves are triggered. We evolved to have pain-sensing nerves around our entire body, because feeling pain is advantageous for obv... | [
"Bleeding doesn't always correlate with the size of an injury, and blood vessels are not innervated with the same nerves that are present in the skin. The nose, like the face and scalp, is highly vasculated so very small injuries can produce a lot of bleeding compared to an injury on the trunk or extremities. Nine... | [
"Then why do spots in your nose really hurt even though they are relatively small?"
] |
[
"Is the empty space near the Sun (say, closer than Mercury) hot or cold?"
] | [
false
] | I know that once you leave the atmosphere things get mad cold out there, and heat needs some kind of medium to propagate through(?). But I also know that the Sun is really, extremely hot, and the heat on earth I presume has to get here somehow. If you were floating in space near the sun, would you burn to a crisp or fr... | [
"The sun radiates 4e26 W, and Mercury is 5.8e10 m away, so the average power an object would receive at Mercury orbit is about 9 kW/m",
" . ",
"The amount of power (P) radiated by a black body is P=σT",
" , where σ is the ",
"Stefan-Boltzmann constant",
". So in order to radiate away all the incoming ener... | [
"Note that this equilibrium temperature depends on the shape of the body, or more specifically, the ratio between its cross-sectional area and its surface area.",
"For example, a black sphere (where the surface area is four times the cross-sectional area) at Mercury's distance to the sun would be heated to about ... | [
"Empty space doesn't have a temperature. It doesn't really make sense to say a bit of nothing has temperature. When someone says \"space is cold\" they're likely talking about the temperature of the cosmic microwave background radiation, which is just a really weak glow in the microwave wavelength of light.",
"... |
[
"Can the same virus variant arise spontaneously in more than one place?"
] | [
false
] | null | [
"Theoretically yes, but it's unlikely. Mutations are random events, both in location and in what they change. There are lots of different kinds of mutations (single nucleotide changes, insertion of new nucleotides, deletion of old nucleotides, etc) that can happen anywhere in the 29,811 nucleotide long genome of th... | [
"This is true, but needs qualification. COVID variants are defined by many individual variations along the genome, some of which (in variants of concern, VoC) may have functional significance but many of which are neutral. That means that even though the same ",
" may arise in multiple locations, it’s far less l... | [
"This is true, but needs qualification. COVID variants are defined by many individual variations along the genome, some of which (in variants of concern, VoC) may have functional significance but many of which are neutral. That means that even though the same ",
" may arise in multiple locations, it’s far less l... |
[
"I've been hearing some talk lately of scientists trying to grow meat in a lab, but what about meat like fungus?"
] | [
false
] | I was wondering to myself a few hours ago how much more or even less difficult it would be to develop a fungus which holds many, if not all the properties we need from meat which we can't find in the plant world. Things like iron and a great number of different acids and other nutrients can't be found in plant life, an... | [
"The only thing stopping us is that it wouldn't taste like meat. :P"
] | [
"I personally wouldn't care if it tasted like meat, I'm currently acquiring a taste for mushroom of different types and I think this would be hugely popular amongst types who would like to be independent and/or vegetarians. Or it doesn't get popular, and I and my family will end up the only ones who want and grow i... | [
"Portobello is already a popular meat substitute. For example, many fine restaurants in the USA serve portobello burgers for vegetarians. "
] |
[
"How do computer components keep track of timings between all of the systems of components?"
] | [
false
] | Example. If I send a single to the processor how do all the transistors capacitors, hard drives, memory sticks, etc all send in back in the same timing for everything to work together? It seems like a lot is going on in my computer and I'm just wondering how it all gets handled to work seemingly flawlessly. | [
"The system as a whole is not synchronized. But components have different ways of agreeing on how to communicate. ",
"In parallel communications, individual bits of data ( 1's and 0's) are transferred simultaneously across multiple conductors called a bus. In this case there are signaling lines that go by name... | [
"Generally speaking they don't. There are drifts between components. What is important is that when they access a common bus they latch the clock of the common source [e.g. your PCIe clock]. ",
"There are collisions all the time on most buses, that's why they build in mechanisms to detect them and work around.... | [
"\"Time of flight\" refers to how long it takes a signal to propagate a distance on the chip. It doesn't happen instantly, or even near the speed of light, due to the resistance and capacitance of the small metal lines it must travel through. Since there are varying distances (and varying resistances and capacitan... |
[
"If Radio Waves bounce off the ionosphere for communications, how can SETI hear anything through the ionosphere?"
] | [
false
] | Wouldn't they need something in space? | [
"Radio waves refract rather than simply reflect. The refraction is a function of the frequency which means higher frequencies pass through relatively straight while lower frequencies can refract enough to come back to Earth.",
"I'm a Ham Radio operator and that refraction is what allows me to talk around the wor... | [
"It's been a hot minute since I took EMag physics, but I'm pretty confident this is a misunderstanding of the underlying phenomenon (refraction, vice absorption and re-emission)"
] | [
"TY for the cool fact!",
"The reason I asked is that I recently got a 3d printer and have decided a fun summer project would be to 3d print some joints and use some radio-reflective surfaces to make a radiotelescope dish. I wasn't clear if it would work or how refraction works, but you've given me a lot of things... |
[
"Are insects able to heal?"
] | [
false
] | If a spider gets cut will it ever heal? Wondering this yesterday when my dog was playing with a moth. Are bugs able to feel pain? | [
"This is one thing that really bugs [edit: no, not \"hemipteras\"] me about many scientists and lawyers.",
"They love to ",
"Bug, when used informally like BrainSturgeon did, means \"any insect, arachnid, or other terrestrial arthropod that is a pest\", or even less formally \"any insect or insectlike invertebr... | [
"Having done cell mechanics studies on fly, I can say yes. Without a doubt, insects are capable of healing. They possess the necessary genes/proteins to do so. Flies even use the same mechanism in their striated muscle (yep, fruit flies have muscle -- and a heart!) to close cuts and wounds as humans do. A ring of p... | [
"It's difficult to generalise too much as there are many hundreds of thousand of insect species, but most are at least able to detect sound vibrations.",
"Others use sound for mating or defence, think of crickets and cicadas, but they might have their ears in a different place.",
"The cricket for instance has i... |
[
"Are there any \"living clades\" (2 or more species whose last common ancestor is not extinct)?"
] | [
false
] | I can't think of any... it could happen, right? Oh and "living clade" is apparently a meaninglyes term that I've just made up, which is probably why I can't google it! And maybe I'm using it wrong anyway, unless I'm also going to insist that ALL the descendents of the last common ancestor are still with us. I would set... | [
"This can get a little tricky with definitions: what you want is two separate populations, which are different species, both of whom have a common ancestor which was a member of a third species, which is still extant, right?",
"The problem may be in how much you variation you'll accept in that ancestral species, ... | [
"This sort of depends on whether you mean the last ",
" common ancestor of a clade, or the most recent common ancestor ",
", but in either case the answer is pretty much no. In the former case, it's pretty obvious that the last individual organism to be the ancestor of two or more species will have died many g... | [
"Thanks for the quality replies!",
"Very glad you got my meaning - I am totally guilty of being vague with terms. I should have stuck to extinct/extant (not alive/dead) and used \"ancestor species\".",
" ",
"Guilty again! I was picturing a typical cladogram in my head and asking questions about extant species... |
[
"Has there been an increase in the amount and severity of storms in the last 10 years?"
] | [
false
] | Hurricane Sandy, big snow storms, tornadoes leveling out cities...are we seeing more of these because of global warming or because of other factors like population increase, news coverage, or the way we measure/record? | [
"I am not a meteorologist, but ",
"this",
" is a paper that specifically discusses tornadoes. It's from 2008, but is a non-paywalled paper that addresses the question \"Does Global Warming Influence Tornado Activity?\". (If anyone has access to more recent papers or information, definitely share.)",
"Check ou... | [
"The most comprehensive survey of the literature on this subject would be the ",
"IPCC Special Report for Extreme Events",
", so that may be worth a read if you're interested in the subject. Meanwhile, this is what I recall off my head:",
" The trends associated with tropical cyclones vary substantially from ... | [
"Officially, it ",
"has been stated",
" that:",
" - ",
"Here's a graph",
" from that page. The chart is obviously going up over time, but it's almost certainly from increased detection rate. The following possible reasons are given by the article:",
"Here's another good article",
". One quote from ... |
[
"Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! ... | [
"How do human crowds flow? I take the subway every morning and I'm amazed that people don't bump into each other more often, even when there are two crowds of people heading directly at each other because of trains arriving. There seems to be an element of following the person front of you, but if two people are h... | [
"While they have the same number of atoms and both are monosaccharides, they are in different formations. Glucose is arranged in a ",
"pyran and fructose in a furan",
" due to fructose having a ketone functional group. This causes several differences in the way each is acted upon in the body. Fructose has a dif... | [
"If there were two consciousnesses inside one brain, would they necessarily know about each other?"
] |
[
"[Medicine] What is the difference between an ulcer and an abscess?"
] | [
false
] | Title says it all. Thank you! | [
"I see...is an aneurysm a form of ulcer, then? ",
"Thank you for your reply!"
] | [
"I see...is an aneurysm a form of ulcer, then? ",
"Thank you for your reply!"
] | [
"Thanks again!"
] |
[
"Question about Higgs Boson's role in creation of the universe."
] | [
false
] | [deleted] | [
"sorry, was on mobile at the time. ",
"about 10",
" seconds or so"
] | [
"Well, the Higgs boson starts to give particles mass when the electroweak symetry is broken. This happened fairly early in the universe's history. Particle-antiparticle annihilation happens throughout the process, but only when the symmetry is broken and the particles acquire mass does their creation require energy... | [
"Could you expand on what \"fairly\" means in this context. From my experience when dealing with the birth of the universe \"fairly\" could mean anything from a billion years to the first few Planck times after the big bang. "
] |
[
"When does the brain actually develop enough to do math?"
] | [
false
] | A kid I babysit can solve 10+4 but not 4+10. I know kids memorize things really well, so it made me wonder if she's actually just memorized all of the sums she knows. Lo and behold, she can't solve the reverse order of any math problems her teacher taught her. When can the brain really start to solve basic math problem... | [
"Piaget goes into this if you read up on his theory, which does have some problems now that we know more about development. Specifically I think it was called inversions or something, where at a certain point the brain develops enough to know that A = B is the same as B = A, which would help a child solve the same ... | [
"Learning stages critical phases have largely fallen out of favour in most neuroscience / cognitive psych research there isnt a lot of evidence for them except in very specific cases like visual selectivity (need early exposure for neural learning in the visual cortex) ",
"The big thing is just exposure currently... | [
"So I just spent 4 months writing a paper on math difficulties interventions and how we learn math. ",
"You've made a few incorrect assumptions in your understanding of the issue. ",
"Learning math requires exposure to numeracy and association of symbolic number and quantity. The IPS is a brain area associated... |
[
"A couple of questions about solar eclipses and the moon's distance from earth."
] | [
false
] | Wasn't sure how to shorten this into a one sentence question. I have a couple of questions that I couldn't find the answer to in regards to solar eclipses, and how they change over time. During a total solar eclipse, 'totality' is when the moon completely covers the sun's photosphere. How much 'room to spare' is ther... | [
"The moon's size in the sky is 29.3 to 34.1 arcminutes (60ths of a degree). The sun's is 31.6 to 32.7. So Depending on how close the moon is, it can be bigger or smaller than the sun.",
"Every thousand years, it would appear one ten-millionth smaller.",
"No, pretty much the same.",
"About 600 million years."
... | [
"I think it's pretty much stable over long periods."
] | [
"Well, the moon is receding at 3.8 cm/year. In 600 million years it will have moved by 23500 km. That would make its angular diameter at perigee smaller than that of the sun. Also keep in mind that the sun will slowly get bigger as well. "
] |
[
"How does ultraviolet light and X-rays escape a black hole?"
] | [
false
] | I understand that astrophysicists detect black holes by finding the ultraviolet light and X-rays escaping from the material descending into the black hole. My question is, does the gravity of a black hole not capture UV light and X-rays, or is the material releasing the radiation before it descends past the event horiz... | [
"My question is, does the gravity of a black hole not capture UV light and X-rays, or is the material releasing the radiation before it descends past the event horizon?",
"The latter. Matter orbiting a black hole can be tremendously energetic due to the massive forces in its small orbit, which leads to plenty of ... | [
"It's not escaping from the black hole, it's from the swirling cloud of gas surrounding the black hole."
] | [
"Again, that's from the schmutz surrounding the black hole."
] |
[
"How fast can a mile be run? Even though it seems there must be a threshold that cannot be surpassed (ex, a 30-second mile is impossible), it also seems that any record could be broken at any time. Is there a way to determine what the best time ever possible could be?"
] | [
false
] | null | [
"This came up in a post on ",
"r/science",
" just a few days ago. I have so far only skimmed the reference d ",
"paper",
", but the idea is to assume that the history of performance in an Olympic event approaches an (unknown) limit exponentially, and use that history to estimate the limit.",
"Unfortunate... | [
"similarly, think about the same idea but as it relates to holding one's breath. ",
"obviously, a person cannot hold their breath forever. however, the world record for breath-holding can always be broken. ",
"you can think about this as it relates to many different things. interesting."
] | [
"I read an article on the theoretical top speed of a ",
"baseball pitcher",
" - I wonder if someone has applied the same science to a runner? There's an enormous number of extra parameters to consider here, however."
] |
[
"What happens to a virus if the host that it lives in dies? Does it decompose with the body?"
] | [
false
] | null | [
"Most viruses don't last long after the death of the host - minutes to hours scale. They require living cells to sustain themselves and with the death of the host and decomposition it's similar to their survival time on any other inanimate object.",
"A few animal viruses can persist for a very long time in render... | [
"Just had the realization that the vast majority of viruses just decompose without ever finding a suitable living cell. Like pollen, trillions of particles get produced and almost none of them actually land on a flower to fertilize and produce a seed."
] | [
"since they’re technically never alive in the first place",
"That depends on who you ask. There is still debate. Viruses have genetic material and evolve via natural selection, and almost certainly share a common ancestor with us.",
"Our definition of life is cellular, which is completely arbitrary and shortsig... |
[
"Do tendons get thicker aswell with strength training?"
] | [
false
] | null | [
"Same with rockclimbing/climbing gyms, Stay of the hangboard unless you climbed regularly 2-3 times a week for 12-18 months",
"",
"*edit for non climbers* hangboard = board with various sizes of small grips, used to train your fingers to support your body weight"
] | [
"Same with rockclimbing/climbing gyms, Stay of the hangboard unless you climbed regularly 2-3 times a week for 12-18 months",
"",
"*edit for non climbers* hangboard = board with various sizes of small grips, used to train your fingers to support your body weight"
] | [
"Absolutely! But it's important to remember that muscles have a very simple action, no matter where they are. They simply shorten themselves. Tendons, ligaments, and joints are the ones that make the shortening muscles into body movement. However, the big muscle groups are easier to control with simple easy mov... |
[
"Induction charging seems like a great idea. Why hasn't it grown much in popularity?"
] | [
false
] | There are a few phones that support wireless induction charging with either a clunky case or a special attachment, but as far as I know nothing really supports it right out of the box yet. I recently got a couple Energizer battery packs for my Wii remotes that came with an induction charging pad, and it's fantastic. Yo... | [
"i think there are a few practical problems with it, primarily, it isn't very efficient. secondly, with a charging pad, if it is placed in any way so that the coil in the device is farther away from the coil in the pad (half on the pad, coil is at the top of the device) then the device may not receive the voltage n... | [
"Wikipedia",
" says it's inefficient, slow, and heats up too fast.",
"There's also the issue that it's expensive for companies to produce, or at least to build the machines they need to produce it. No matter how cheap in the end, a paradigm change is expensive."
] | [
"I personally would avoid inductive charging for my cell phones. I can't count the number of times I've overused my cell phone and needed to plug it in so I could continue using it. The thing is, a plug can easily be moved around, I can hold the phone to my ear, I can lay in bed with it. None of these options would... |
[
"What's the difference between a mutagen and a carcinogen?"
] | [
false
] | I work with ethidium bromide in the lab, and was told that it was a mutagen by my professor. He said he's not sure why it's not considered a carcinogen, as cancers are caused my mutations, and the mutagen causes mutations. Can anyone clarify? | [
"To adapt some biological terminology, a mutagen is classified based on its genotypic effects (does it cause mutations), while a carcinogen is classified based on its phenotypic effects (does it cause cancer). While many mutagens are indeed carcinogens, not all of them are. Without evidence clearly connecting expos... | [
"Just to be clear on this, have they tested it in multiple things and only found that it induces mutations in ",
", or have they only tested it in ",
"? Also, did they test it to see if it's carcinogenic and not found the results to be statistically significant, or have they not tested it?"
] | [
"A mutagen is any factor that has the potential to cause mutations. ",
"A carcinogen is a mutagen that has the potential to cause mutations in oncogenes, anti-oncogenes, apoptosis regulating genes, DNA reparation regulating genes and cellular senescence regulating genes. Basically, any gene involved with growth, ... |
[
"If humans were to evolve again, what is the most likely change that would be observed?"
] | [
false
] | null | [
"We are constantly and continuously evolving"
] | [
"If so, what are the changes that could largely distinguish us from humans (20000?) years ago?"
] | [
"I recommend making a new post with just that question"
] |
[
"Is there a size limit to phagocytosis?"
] | [
false
] | My understanding is that antigen presenting cells phagocytosis a pathogen and are leftover with antigens. What if it's a big parasite or cancer cell thats too big how do they get the antigens to present to start a adaptive response. | [
"Eosinophils are typically responsible for larger intruders such as parasites. A bunch of them will gather around the parasite and collectively secrete potent toxins that will kill it, since they cannot phagocytize it"
] | [
"What happens to the bodies of parasites that die in the human body? At what rate do they decompose and how does the body deal with that?"
] | [
"When confronted with bacterial or yeast structures (e.g. filaments, aggregates, biofilms) that are too large to engulf, macrophages and neutrophils often become “frustrated” and will release their lysosomal components into the environment in an effort to kill the pathogen extracellularly. Unfortunately, those eff... |
[
"A woman with a long history with major chemical corporations told me yesterday that CO2, Diamonds and Pencil Lead were Organic, is she right?"
] | [
false
] | Now to Clarify I work with this woman, L (chemist with history at major chemical producers) I'm in the IT Department, we had dinner last night with another colleague (PhD environmental biology). Now during the meal they were chatting chemistry and L's work history and such, I wasn't paying full attention because I don'... | [
"The term \"organic\", in chemistry, is defined somewhat arbitrarily. Some define it as compounds that were at some point part of a living organism. A more common definition is a compound with a carbon in it, but excluding a few groups of compounds such as carbonates, carbides and simple carbon-oxides (such as CO2)... | [
"Diamond, graphite, CO2 are absolutely organic compounds."
] | [
"Dictionary agrees",
"3 (Physiology) relating to a bodily organ or organs.",
"My understanding is that sense 1 came first, and then they realised that some organic chemical compounds could be synthesised, and that related compounds could be synthesised only. So it was easier to simplify the definition to includ... |
[
"Why is the double Oxygen-Oxygen bond energy more than double the energy of the single O-O bond?"
] | [
false
] | The single oxygen bond energy is 146 kJ/mol and the double bond one is 495 kJ/mol. My understanding was that the second bond that are formed are Pi bonds, which are supposed to be weaker than the primary Sigma bonds, so the energy of the double bond is supposed to be lower than twice the value of the single bond energy... | [
"Resonance with what?"
] | [
"My understanding is that the standard bonding model is not quite correct. Molecular orbital theory explains the orbital mixing that occurs when atoms bond. In the case of the \"double bond\" oxygen-oxygen molecule, ",
"this diagram",
" shows the orbitals mixing from each respective oxygen atom. As you go ... | [
"Yea, but why in the specific case of oxygen does the bond strength demonstrate such a significant gap? "
] |
[
"Can somebody please outline the differences between the \"strengths\" of a sphere and a triangular pyramid as three-dimensional shapes in terms of resisting force?"
] | [
false
] | My roommate and I got in an argument as to which of these shapes is the "strongest". I understand that this term is incredibly ambiguous but he's an idiot. His stand is that a triangular pyramid is the most stable shape under any gravitational circumstances, under any force, placed on any part(s) of the pyramid. Mine i... | [
"Woohoo! A question I can actually claim to be an expert in!",
"I'm a structural engineer, so I sure as hell hope I can answer this.",
"Each shape is optimal for different loading conditions. ",
"The pyramid is useful only for vertical load imposed at its peak. If you place a horizontal load at the top of the... | [
"You are prettymuch correct in your analysis of a sphere being superior in its circumstance, but it is important to clarify that it really depends on the situation that each shape is in.",
"Triangles and pyramids are frequently used because they split the force applied on them into tension/compression forces appl... | [
"What's the maximum height we can build with current building material?"
] |
[
"Does white noise sound different for everyone??"
] | [
false
] | If white noise is a combination of all frequencies of sound that humans can hear, and people hear certain frequencies more than others, does that mean white noise sounds different for other people? Do old people hear white noise as a lower "note" than young people? | [
"White noise technically every frequency playing back at equal levels. The general frequency range of human hearing is 20hz-20khz. Everyone might experience it ever so slightly different depending on their range when they’re born but typically you start to experience hearing loss as you grow older. You might hear f... | [
"Yes! Also the perceived loudness is different since everyone hearing ability is a bit different. Furthermore the tonal perception is also dependent of the playback level since everyone perceives the relative loudness of tones not independent of the level of the tones.",
"Interesting side fact: there are also man... | [
"It would be a hard question to answer empirically (how do you compare the pitch of white noise across individuals?) but I think your intuitions are probably right: someone with better sensitivity to higher frequencies would hear white noise as having a higher, or more fine-grained, pitch.",
"White noise has powe... |
[
"Does white paper reflect UV light?"
] | [
false
] | If a person is reading a sheet of white paper outside, does the paper reflect UV into his/her eyes? Is the amount reflected enough to be a possible cause of damage? | [
"Correct me if I'm wrong, but I don't see the direct implication there. Paper definitely does shine under blacklight, but that only tells us that paper absorbs some of the UV spectrum and re-emits it at lower frequency. Mirrors apparently don't really reflect much of the UV that hits its surfaces. I would like to s... | [
"Yes. Yes.",
"White paper gets real bright under a black light. Which is part of the UV spectrum. Unbleached untreated paper doesn't glow as much.",
"Looks like printer paper glows because of how it's treated. ",
"https://www.thoughtco.com/what-glows-under-a-black-light-607615",
" ",
"Eyes can get sunburn... | [
"You're talking about quantity and quality of reflection now. Initially you were asking, \"yes or no?\" That I can't answer really answer, depends on the paper.",
"Fact is some UV does get reflected, some gets absorbed.",
"If you are throwing more UV from the sun at the paper more or less will get reflected, or... |
[
"What is our best hope for sustainable energy?"
] | [
false
] | And I mean completely sustainable. From the materials within a solar cell, to the base of a wind tower. I guess there needs to be two answers, 1 for electricity generation, 2 for powering vehicles (unless they were also electric, but then what about batteries?) | [
"\"Sustainable\" is a marketing word. We can't sustain anything indefinitely, every element has a peak, and ",
"we will consume as much energy as we save with more efficient technology.",
" Do you mean what is the energy technology we can exploit the longest, given today's understanding? ",
"That would be t... | [
"There is a finite amount of them on the planet. In a great many cases we can recover them, but all recycling takes energy. The only way to harness solar renewably is with plants, but that depends upon sustainable agriculture if you're actually going to count it as renewable. We don't currently have our ag syste... | [
"This is one of those questions where if you ask 100 different people you will get 100 different answers.",
"I can't speak objectively because I am not aware of all the latest innovations in every field of power generation. But from a purely physics point of view, all the energy on Earth comes from our sun. Win... |
[
"How do fetuses get nutrients from the umbilical cord?"
] | [
false
] | null | [
"Blood carries nutrients. ",
"Fetal and maternal blood flow very close together at the placenta and, sort of like air in the lungs or food in the digestive system, nutrients (and oxygen) cross from the mother's blood into the fetus's and then that flows into the baby."
] | [
"Oooooh so, the mother's and baby's blood doesn't mix while she's still pregnant? Damn never knew that "
] | [
"Afaik it mixes during birth which is why Rh incompatibilities show up after the first pregnancy ( neg mother, positive baby is ok the first time )"
] |
[
"Humidity below water's freezing point?"
] | [
false
] | It is currently -9 °C with 34% humidity. How has the water vapor not condensed out of the air? | [
"There is always going to be some equilibrium through out a system. The humidity present within the air is from the water molecules that are still present within the air.",
"At an atomic level, the frozen water indicates that the molecules have slowed down enough to form a crystal structure with other molecules o... | [
"Awesome. That is simple enough. Often I find the answers to a lot of my chemistry questions are the obvious ones. I have a pretty solid working knowledge of chemistry, 5 college semesters, but certain things were never expounded upon in school.",
"So as a sorta follow up: Does an isolated atom (I guess hypotheti... | [
"Certainly not \"any and all\" physical characteristics. An individual atom has mass, velocity, charge, the capacity to absorb and emit photons of certain wavelengths from its electron shell, the capacity to interact with other atoms and molecules chemically, etc., etc. Which were the characteristics that you had i... |
[
"If you listen to music loudly (via earphones) in a very windy situation, where you can barely hear the music (for example in a convertible going fast), is the music still doing damage to your ears?"
] | [
false
] | null | [
"Yep. Same thing with being at a bar or loud concert and yelling into your friends' ears so that you can hear each other. No different then if someone was yelling into your ear in a quiet room. "
] | [
"Okay thanks man.",
"One more question. Say the wind is say 120 decibels and your music is 110 decibels loud, does this mean you're listening to a combined 230 decibels or 120 decibels of loudness?"
] | [
"One of the leading causes of hearing loss for motorcycle riders is \"wind noise.\" So playing music that is even louder than that most definitely has damaging potential. "
] |
[
"If a satellite is orbiting a body, will its orbit decay if there is no drag?"
] | [
false
] | I have been pondering about this since i've been studying physics recently and after some lengthy google searches i have found that the answer is no, but why? If it has velocity and the only force being applied to it is gravity, then the net force is a vector pointing towards the body it is orbiting since velocity is n... | [
"With a spherically symmetric primary, a satellite, and nothing else, and ignoring the existence of gravitational waves, the satellite would stay in a Keplerian orbit forever.",
"Since gravitational waves do exist, the satellite's orbit will decay via their emission. This will take a gazillion years though.",
"... | [
"You are in a misconception indeed. The misconception is in this part:",
"And since the net force applied to the body is not 0 then its velocity cannot be constant",
"The velocity of the satellite is not constant, the ",
" of velocity is (i.e. it’s speed). Since the satellite is not moving in a straight line ... | [
"satellites ",
" constantly accelerating due to gravitational forces; but in a circular orbit, since that acceleration is always \"sideways\" to their direction of travel, their speed (but not velocity) stays the same.",
"in an eliptical orbit (where one side is lower/closer to the planet), they do go faster at... |
[
"Does having only one testicle affect testosterone, muscle growth, etc?"
] | [
false
] | [deleted] | [
"Urologist here. Most of the time, men remain eugonadal. However, some men who have orchiectomy for cancer do become hypogonadal. Many (but not all) of these men, however, have adjuvant treatment with chemotherapy or radiation which contributes to low T. However, up to 15-20% of patients who have orchiectomy on... | [
"our remaining testicle compensates for the one that you lost. Your remaining testicle has the capacity to produce fuckloads more testosterone than you need. How much they produce is determined by how much you need.",
"Slightly simplified explanation:",
"Testosterone is produced by Leydig cells in your testicle... | [
"There is no evidence that masturbation causes low testosterone"
] |
[
"What are the advantages and disadvantages between nationwide 110 volt and 220 volt standardization?"
] | [
false
] | null | [
"Higher voltage allows the same energy to be transmitted with less current and thus less loss through resistance and heat. ",
"Lower voltage is safer.",
"http://en.wikipedia.org/wiki/Electric_power_transmission",
"Basic properties of resistors: ",
"http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/first11/pa... | [
"We just returned to the US after living in Germany and traveling extensively throughout Europe and UK. I also have some technical expertise in this area. As mentioned in many other posts, volts X amps= watts. The power used by a device is measured in watts. Most of the household wiring in the US is 110v with ... | [
"Safer in two aspects: For a given resistance (like a human body) the wattage that flows through will be lower with a lower voltage; and for electrical systems, higher voltage can be disruptive even for low wattage (like a stun gun, for example).",
"In practice, we compromize - keeping the voltage very high for... |
[
"Do Kepler's laws still hold in general relativity?"
] | [
false
] | Newton's inverse square law was shown to be not quite accurate in describing planetary motion. Do some or all of Kepler's three laws of planetary motion hold up against general relativity? | [
"In General Relativity, Kepler's Laws are demoted to being very accurate approximations. We still use them and use them, but we know that they're not the whole story.",
"However, even in Newtonian mechanics, Kepler's Laws are still technically an approximation. Kepler's Laws assume that all of the mass of the sys... | [
"We still use them and use them, but we know that they're not the whole story.",
"Kepler's Laws are some of my favorite examples for \"a theory doesn't need to be completely accurate to be useful in some circumstances.\""
] | [
"One of the most famous tests of general relativity is its deviation from Kepler's first law.",
"Mercury doesn't orbit in a perfect ellipse (none of the planets do, but the effect is most pronounced in Mercury). Instead, it's roughly an ellipse that changes the direction it points over time. This changing of the ... |
[
"Is it possible to perceive a surface of some size as having one and only one color?"
] | [
false
] | I understand that electro-magnetic radiation can not be strictly monochrome, so in physics there is no object that has only one color. But than I also understand that our perception of color is quite different from physics. When I look around in my office, I can look at which ever surface and will find that they all co... | [
"You can certainly have effectively monochromatic radiation, a laser for example."
] | [
"Yes. In fact, its possible to have surfaces with different spectral reflectance distributions that are perceptually indistinguishable. These are called metamers. "
] | [
"Do you mean, why do they appear the same to us?",
"It's a common misconception that we have \"red,\" \"green,\" and \"blue\" cones. Actually, cones respond to a range of wavelengths, with peak responses occurring for different wavelengths. A single cone's response depends on two things -- the amount of light (am... |
[
"For people who have a tracheostomy, are there cases where the body heals itself to a point where the tracheostomy tube is no longer needed?"
] | [
false
] | Does this differ in adults of varying ages and children? Does it differ if the cause of the initial tracheotomy was because of smoking vs. paralysis of the vocal cords? | [
"I'm an otolaryngologist-head and neck surgeon.",
"The most common reason I'm asked to do a tracheostomy is to either relieve an acute or chronic airway obstruction or to take the stress off of the larynx (voice-box) of a patient who may need respiratory support in an intensive care unit for a prolonged period.",... | [
"In the NICU we use non-cuffed tubes, which do not cause pressure on the trachea like cuffed tubes do. Cuffed tubes are used in adults, and literally have a plastic inflatable sleeve that is inflated to a certain pressure to keep the airway sealed around the tube. NICUs use tubes without that sleeve, and allow a... | [
"Can I ask why NICU babies can be on ventilators for months and they dont have the same damage?"
] |
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