title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
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[
"If the distance between astrological objects is expanding, how come The Milky Way and Andromeda galaxies are predicted to collide?"
] | [
false
] | [deleted] | [
"(Astronomical, not astrological!!)",
"The expansion of the universe is a large scale effect. The further two objects are from each other, the more rapidly they are receding from each other due to the expansion of space between them. But on a small scale, things can approach each other and collide and do all sort... | [
"I can't believe I said astrological omg. And thanks for your answer!"
] | [
"If you bring two small magnets together, they will 'snap' together when you release them. But if you hold them a distance apart, even if it's just an arms length then nothing happens - they will just fall to the floor. The reason is that the magnetic force between them varies with the inverse of the square of the ... |
[
"How do lakes, ponds, and rivers, and even puddles retain water without it seeping away into the ground, as if I dug a hole and poured water into it?"
] | [
false
] | null | [
"All of these have water sources that refresh their losses. The ground under those things is already wet so it drains much slower.",
"When it starts to rain the ground usually eats up all of the rainfall at start, but after a while places can start flooding."
] | [
"Look up \"water table\". Rivers, lakes, and puddles sit on top of ground that is already wet.",
"If you dig a hole deep enough, you go down to the water table, and water will ooze out of the moist ground and fill the hole."
] | [
"This. If you dig a well, it fills with water because of the ground water around it, but stops when its level reaches equilibrium. Lakes are at equilibrium with the surrounding water table, like a well that has filled in."
] |
[
"Why is the color spectrum cyclical?"
] | [
false
] | The color spectrum goes from low red frequencies to high violet frequencies, but violet seems to flow evenly into red, but why is that if they're on the opposite sides of the spectrum? | [
"here's an answer to this question i gave a while back",
".",
"someone is going to come in here and claim that red color feels next to blue (with purple/violet in between) because the L cone (the \"red cone\") has some sensitivity to short-wavelength light. but there's no evidence (or logic, really) for that ex... | [
"someone is going to come in here and claim that red color feels next to blue (with purple/violet in between) because the L cone (the \"red cone\") has some sensitivity to short-wavelength light",
"I was looking at this thread precisely to see if someone is spouting this stuff again, as it always comes up, so I'm... | [
"You have to understand; the electromagnetic spectrum by itself indicates no visual color. It is our cells that produce the \"color\", by interpreting the wavelengths.",
"So the real question to ask is why the same cells respond to both low wavelength and high wavelength colors."
] |
[
"Is being a \"heavy\" or \"light\" sleeper a product of genetics or conditioning, and are these attributes able to be changed?"
] | [
false
] | I am a very heavy sleeper and would like to know if there's anyway to wake up easier. Also, I've always just wondered why some people sleep the way that they do. | [
"Sleep, like all behaviors, is affected by both genetics and environmental factors. There have been some genes discovered that associate with differences in sleep duration, e.g., ",
"a mutation of the DEC2 gene was found to be associated with a particular family of short-sleepers",
". However, it's very early d... | [
"Here's a great article",
" on sleep spindles in individuals and how it changes how light/heavy they sleep. Individuals tend to become \"lighter\" sleepers as they age and they lose some of the \"sleep spindles\" that allow heavy sleep without interruption to occur. This also ",
"appears to be genetic",
" ho... | [
"So if I understand this correctly, being a heavy sleeper means I have more spindles. If I were to introduce more noise while I slept, would I possibly become a lighter sleeper, thus being easier to wake up?"
] |
[
"Is obesity a genetic problem that can run in families, or is it more likely that children pick up the poor eating habits of parents?"
] | [
false
] | null | [
"Yes and Yes. There have been some genetic associations to obesity that are inherited (associations that are not necessarily causal), but familial factors like learning poor eating habits are seen in most, if not all, obese patients, and will compound the problem in patients who could have a genetic susceptibility ... | [
"Eating habits of the mother while the baby is in utero has also been shown to play a role"
] | [
"Second this! Anyone curious should research the Dutch famine that took place during WWII when the Germans blocked supplies into the country. In the decades following this event the cohort of children born to Dutch women who were pregnant during the famine have been studied. If I recall correctly the timing of th... |
[
"When did human beings start exercising?"
] | [
false
] | From an anthropological standpoint, when did humans start developing and using exercises to improve physical fitness? When did we discover that repetitive motion + resistance = growth? | [
"Physical activity for the sake of fitness began when we'd progressed to the point that members of society could survive without significant physical exertion - i.e., when society had reached a point where physically contributing members could support nonphysically contributing members to a degree where a primarily... | [
"Every predator that I can think of utilizes play beginning at an early age to hone skills, and improve strength and conditioning. I would argue that is the foundation of what we humans have refined into \"exercise\" and this foundation stretches further down the evolutionary tree than just humans. So when did huma... | [
"The Chinese dynasties span thousands of years. I don't think that answers ",
" very well. If TMarkos knows of references then he or she could provide them. Is this the only known instance of exercise for the sake of health during this time period? If so, why did this occur in Chinese dynasties and not other ... |
[
"How long is the actual process of supernova explosion?"
] | [
false
] | [deleted] | [
"I actually ",
"answered",
" the first part of this just recently!",
"The supernova explosion itself lasts of order ",
"100 seconds",
". However, the effects thereafter can be seen for months or years.",
"For the second part of the question, the explosion can be visible from Earth as a point source but ... | [
"You missed an ) in your link. Great answer though I always wondered if it was a split second thing or if it lasted a while just due to the size of the thing that is exploding."
] | [
"Whoops, thanks!",
"It's obviously a very complex thing but the star itself just before the explosion is very large. So it takes time for the shockwave to propagate through even the surface of the star, up to ",
"a few hours",
". So I guess it's tough to say how long \"the process\" lasts as there are a lot o... |
[
"What's up with wisdom teeth?"
] | [
false
] | Why do they grow in our mouths if they don't fit? Why do some people have to get them removed, but some don't? What did our ancestors do without the technology to remove them? | [
"\"Wisdom teeth are vestigial third molars that human ancestors used to help in grinding down plant tissue. The common postulation is that the skulls of human ancestors had larger jaws with more teeth, which were possibly used to help chew down foliage to compensate for a lack of ability to efficiently digest the c... | [
"I know several people who never even developed wisdom teeth, and this is becoming more common. Evolution in action!"
] | [
"Maybe she was referencing humans from 10,000 yrs ago."
] |
[
"Is kissing a learned behavior?"
] | [
false
] | In humans, is kissing a learned behavior or is it more instinctual? | [
"Cracked.com",
" says it was ",
"evolved to protect us from viruses."
] | [
"Cite their source:",
"http://leeds.academia.edu/ColinHendrie/Papers/1207409/Kissing_as_an_evolutionary_adaptation_to_protect_against_Human_Cytomegalovirus-like_teratogenesis",
"Also it's speculation."
] | [
"That's up for debate. There was a popular science article on the news about it recently that I believe suggested it was learned. It certainly has a long history, but there are some cultures that don't kiss. "
] |
[
"Is our peripheral vision any more sensitive to movement than our 'standard' vision?"
] | [
false
] | Today's reminded me of a question that's been on my mind for a while. I've noticed that I'm much more aware of the flickering of neon lights, LED screens, train departure information displays etc. when I see them out of the corner of my eye. Is it the case that our peripheral vision has a higher 'refresh rate' as it we... | [
"The rod cells are better at ",
"registering flicker",
" and predominate at the edges of the visual field."
] | [
"Your peripheral vision is fed by \"Rod Cells\" in the eye. These cells are packed on the outer edges of the fovea (the center of your eye) and are therefore pick up information from the environment that is not directly being looked at (peripheral visual space). Your direct vision is supplied by \"Cone Cells\" in t... | [
"The article in wikipedia confused me.\nIt says that rod cells are sluggish, and the platau of the fusion frequency for the rod cells is 15Hz, while for cone cells is 60Hz.",
"But, in the next paragraph, it says that the rod cells of the human eye have a faster response time than the cone cells.",
"Isn't it a c... |
[
"Are you still briefly conscious after being decapitated?"
] | [
false
] | From what I can tell it is all speculation, is there any solid proof? | [
"Did the nazi's perform any tests regarding this subject?",
"EDIT: Why the downvotes? This is a good and legitimate question. The nazi's both killed large numbers of people and were very scientific with all their experiments and kept meticulous records. Like it or not, we have a lot of good scientific data from t... | [
"Just a reminder that genuine questions should not be downvoted. Thanks!"
] | [
"Neuroscience Ph.D Candidate Here. I've had this question for a long time, and actually did a bit of research into it. Here's one ",
"article",
" I found useful in answering this question, at least in rats. ",
". ",
"The authors report \" It is likely that consciousness vanishes within seconds after dec... |
[
"If matter and energy are two sides of the same coin, and matter has a charge opposite of anti-matter, is there an anti-energy?"
] | [
false
] | null | [
"Not matter and energy. Mass and energy. There is anti-matter but there is not anti-mass."
] | [
"They both have positive mass. There is no reason to suspect that antimatter interacts differently with gravity than matter, but that hasn't been tested because it's difficult to observe gravity on the atomic or sub-atomic scale."
] | [
"How do matter and anti-matter interact with gravity? Do they both have positive mass?"
] |
[
"Can a star be far enough away from Earth that it's light never reaches us?"
] | [
false
] | The speed of light, when passed through a medium like water, can stop completely over a distance of a kilometer. If space is not really a vacuum, instead being made out of an extremely low-density medium, how far away does a star have to be, so it's light does not reach earth? | [
"Basically, we won't be able to see anything further from us than the distance in which space expands at a rate larger than 1 light-year per year",
"That's actually not correct. Many of the objects we can see have recessional velocity greater than c. In fact, some of them have ",
" had recessional velocities gr... | [
"Yes! However not for the reason you're describing. Space isn't an extremely low-density medium (like the ",
"aether",
") - it's a near-vacuum with very few particles, true - according to ",
"this",
" it's 10-100 atoms/cubic meter. ",
"Space is expanding. There are galaxies on the other side of our vis... | [
"Thank you for the correction - so do you know where the cutoff is?",
"I knew that we can see objects with recessional velocities >c but for some reason that never clicked for me. I guess sometimes it takes someone bludgeoning you with a fact for you to understand it. "
] |
[
"Is there any planetary body in our universe that doesn't move?"
] | [
false
] | I know that objects can be stationary relative to other objects like to ourselves, the milky way is stationary. But what I am wondering about is if there is anything out there that is truly not moving/no kinetic energy. And if it is not possible, why not? | [
"There is no way to determine if anything is standing still. There is no reference point to compare it to. The only way we judge if something is moving is compared to another object. ",
"We don't have a natural spacial grid that everything lies on that we can compare to.",
"The milky way is moving through sp... | [
"Other than the invariance of the speed of light, that's the crux of relativity right there."
] | [
"And to finish off the thread: kinetic energy also changes with your frame of reference, so saying something has \"truly no kinetic energy\" doesn't make much sense."
] |
[
"What's the difference between formulas, algorithms and equations?"
] | [
false
] | null | [
"An equation always has an \"equal\" sign in the middle, and declares that the two things on either side of it are equal.",
"A formula is a type of equation.",
"An algorithm is a defined series of instructions...a recipe or procedure."
] | [
"A formula is a type of equation.",
"Invert that. An equation is a type of formula. Formulas are symbolic representations of information, there's no real concrete definition so this probably misses a few bases. For instance,",
"triangle inequality",
"Algorithm also has a variety of formal and informal definit... | [
"To be more specific about the formula thing, they are equations with a defined purpose. y = x is an equation, but it isn't very meaningful in terms of practicality. A formula is an equation with variables that express known quantities that you can use to calculate unknowns. For example, knowing a given quadratic e... |
[
"How are normal ocular motor movements seemingly preserved in ALS? Are they generally unaffected in other motor neuron diseases?"
] | [
false
] | There are sites that state both oculomotor movements and bladder control remain generally unaffected: But I've also found studies dating back to 1995 that suggest there is gradual oculomotor impairment in patients with ALS: Why are oculomotor movements the last to go (if at all)? | [
"Not necessarily. Bulbar-onset ALS is a clinical entity with a generally worse prognosis. But even in those patients EOM activity is usually preserved.",
"This article",
" talks about postmortem pathological changes in EOMs and points out that EOMs are a distinct muscle allotype because they tend to behave diff... | [
"ALS is not well understood, but what we do know is that the motor neurons in the lateral part of the spinal cord sclerose (hence the name). The ocular muscles are controlled by a cranial nerve which is up in the brain, and these nerves survive much longer in the course of the disease."
] | [
"I probably should have said ",
" preserved. Decreased saccadic velocity and other abnormalities can be found, as occasionally can diplopia. But not like, say, the shrunken, twitchy tongue and masked facies of a man I saw in residency with bulbar-onset (but by then clearly upper- and lower-limb involving) ALS."
] |
[
"Do thin people have more sensation on their skin because their nerves aren't as spread out?"
] | [
false
] | null | [
"To a certain extent yes, the nerve endings can be closer together and have more response but it's largely overruled by other things I.e personal threshold for pain, the circumstances of whatever stimulus, medications... Its a factor yes, but not one of particular influence.",
"Edit: Closer together, not closer... | [
"The assertion is that a bigger person doesn't grow more nerves to cover the larger surface area as compared to a smaller person. So, a smaller person with a smaller surface area would have nerves closer together, not more nerves or smaller nerves. ",
"Now the word nerve sounds funny."
] | [
"Huh? That doesn't make sense.",
"Closer packed nerve endings send a perceived stronger signal because more nerves are firing, but single nerve for nerve the pain experienced would be the same for Tubby or Twiggy if all other factors were perfectly equal for both parties."
] |
[
"Why is ATP the molecule that supplies biological energy, instead of any of the other nucleotide triphosphates (i.e. UTP, GTP, CTP, or TTP)?"
] | [
false
] | Also, are there any instances of cells that use any of those other triphosphates as a power source instead of ATP? | [
"Well, first it is helpful to separate ATP and GTP, which are both purines, from UTP, CTP, and TTP which are pyrimidines. The size of the purine base would give it different binding properties (larger hydrophobic surface area) than the smaller pyrimidines. ",
"The next useful thing to notice is that both ATP and ... | [
"I am not sure if predominantly using ATP was random or was just thermodynamically the most favorable, but I can shed light on where other nucleotides are used in metabolism.",
"GTP is actually used as an energy resource in protein synthesis, gluconeogenesis and in signaling (specifically G Protein coupled signal... | [
"I was also going to come here and suggest GTP. It is also used in forming microfilaments in the cell's cytoskeleton. The dimer must be bound to GTP to be in the right conformation to grow the microfilament. When GTP is hydrolyzed the conformation is destabilized and the microfilament breaks part. ",
"Edit: J... |
[
"Force-carrying particles and other misc questions?"
] | [
false
] | null | [
"Your confusion comes from the idea that interacting objects are constantly shooting particles at each other, which isn't the case. If that were true, we'd see, for example, glowing light between two magnets. Really, it's an idea that perturbations in a field due to a particle can be treated like another virtual pa... | [
"Gravitons vs Space-time Curvature",
"These are actually not as different as you might think, and in fact the other forces work in a similar way. Gravity is still pictured as the curvature in space-time when talking about gravitons, it's just that traveling waves of this curvature have to exist in small chunks of... | [
"So how does this relate to Gravitons and Spacetime? Is the entirety of Space a field too?"
] |
[
"At what altitude would by phone stop getting signal (including from satellites)?"
] | [
false
] | [deleted] | [
"Cellphone towers typically have ranges from 22 to 45 miles. From what I understand, an omnidirectional antenna is impossible, so cellphone towers probably have a shorter range going up. Space is generally accepted to be around 100 km up (62 miles), so the ISS has no reception."
] | [
"Cellphone towers typically have ranges from 22 to 45 miles.",
"What's your source for this number? I don't think we can really use it here without knowing what assumptions are behind it—more likely than not, it assumes surface-to-surface communications, which are limited by:",
"From the ISS the distance to th... | [
"From what I can find, the taller cell towers are about 200 feet high, which gives them a horizon 17.3 miles away. So apparently it reaches beyond the horizon. I guess that means they should be able to reach further into the sky.",
"To get maximum signal you ideally need a radio that tunes in 1 kHz or smaller ste... |
[
"How plausible is the \"Born To Run\" ideology?"
] | [
false
] | To all with a background in biology/ anatomy- The Barefoot running campaign has caused quite a stir in the running community. Basically the idea is that Humans have one good ability as hunters: the ability to sweat well. Many then take it a level farther and say that our human ancestors used to out-endure our prey be... | [
"I'm all for it, personally. The background thesis is good (evolved with bare feet > running well is selected for > designed to run barefoot as opposed to shod), but running strictly barefoot or minimally shod is not as important as the forefront strike it encourages. ",
"Nature",
" published one of the first s... | [
"it works for me. When I run barefoot I feel like I can go twice as fast and never stop. ",
"that aside, running on your toes reduced stress to your knees (reduces the shock of hitting the ground with your heel instead of easing into it with your feet). running barefoot lets you use the muscles on your toes to pu... | [
"I think the \"terrible for your feet\" idea comes from the fact that our ancestors may have run barefoot, but they didn't run on asphalt or gravel, which could also hide things like broken glass or metal. So that's why running in a pair of Vibrams or other \"barefoot shoes\" simulates running barefoot, but still p... |
[
"How can cellulose be both hydrophilic and insoluble in water?"
] | [
false
] | [deleted] | [
"Great question. If you look at cellulose, you will notice that it commonly exist as a polymer chain, which is where this contradiction arises. It is hydrophilic and attracts water molecules due to its functional groups, but since it is in a polymer chain, water does not have the ability to \"surround\" completely ... | [
"Additionally, polymers in general are far less soluble than monomer because of entropy. Cellulose can hydrogen bond, but not as well as water, and polymers have low entropy because they are physically bonded and their configurations are constrained."
] | [
"Hydrophilic and soluble aren't necessarily the same. If something is too big, or heavily cross-linked, it will be an aggregated solid and not soluble. Cellulose is both. "
] |
[
"Why do humans make similar facial expressions in response to similar situations? Nature, or nurture?"
] | [
false
] | [deleted] | [
"This. I have a lot of Paul Ekman's books and bought his Facial Action Coding System. Lie to Me is so horrifically inaccurate it makes me cry.\nAnyway, the answer is nature. Ekman has done a lot of work on this with peoples from around the world...following in Darwin's footsteps by the way...and has talked about it... | [
"This. I have a lot of Paul Ekman's books and bought his Facial Action Coding System. Lie to Me is so horrifically inaccurate it makes me cry.\nAnyway, the answer is nature. Ekman has done a lot of work on this with peoples from around the world...following in Darwin's footsteps by the way...and has talked about it... | [
"Sorry if my opinion on Lie to Me came across as a slight against you at all...not my intention.\nI was a pro poker player for a while...hence all my Ekman books. I also had books on poker tells, human physiology, FBI profiling of body language, etc etc. \nAfter watching those vids from Ekman, you surely know that ... |
[
"What are the critical temperatures, pressures and volumes of a van der Waals gas?"
] | [
false
] | Sorry if my wording is poor; I'm only starting to learn this. After doing some research online to help further my understanding of what a critical temperature and pressure (no luck on finding any information on critical volumes) of a van der Waals gas are, I discovered that the definition of a critical pressure seems t... | [
"This wiki should answer your questions: ",
"http://en.wikipedia.org/wiki/Critical_point_(thermodynamics)",
"At the critical point, the properties of a gas and a liquid converge such that you have one phase. The critical temperature is the highest temperature that 2 phases can coexist, the critical pressure is... | [
"Yes, above the critical temperature there is only one phase, a supercritical fluid.",
"Vapor Pressure: When a pure solid or liquid is in equilibrium with its gas phase, the pressure of the gas phase is the vapor pressure.",
"Here is a video of supercritical CO2 that may help to visualize the process.",
"http... | [
"The ",
" temperature, and not the lowest? Thanks for the wiki. :) I think it might have answered some of the questions ctulhuflux raised (sorry, ctulhuflux). Also, if you can, can you elaborate on what the vapor pressure is? I'm finding it a little difficult to understand Wikipedia's definition. :)"
] |
[
"Ignoring interplanetary travel requirements, what would be needed for a self-sustaining Martian colony?"
] | [
false
] | What technologies would be required for colony structures, harvesting water and raw material, where would the ideal place to build such a colony be, and what environmental hazards would have to be accounted for in any colony design? (Plus anything else I haven't thought about.) | [
"Mars has a very weak magnetic field, and it's not enough to deflect cosmic radiation or solar wind (and it's the same with the Moon, only the Moon has the additional woe of getting swiped by Earth's magnetic tail about once a month). You would need some serious radiation shielding. Beyond that, you would need a la... | [
"Okay, a lot of this sounds like startup for a very small colony. What about a large colony? 100k+ individuals?",
"Would Valles Marineris be a good spot to build, given its low altitude meaning denser atmosphere and equatorial geography for better temperature?",
"What precautions would need to be taken for the ... | [
"It might be a good idea to dwell in the caldera of Olympus Mons, since it's quite extinct, and at a high altitude. This way, you could construct a very large cap and use the entire surface area of the inside space. A very large space-ramp could be built, or carved out and polished, on the side of the mountain itse... |
[
"What is the purpose of microcontrollers having a clock cycle?"
] | [
false
] | Couldn't it just work continuously? | [
"Not really becuse how else would you know when a \"new state\" has began? Imagine that you want to process bits that come as an input to your microchip. If they are always 0-1-0-1... it's fine but what happens if its 1-1-0? How do you know if it was a single 1 or double or triple? Clock helps with this because it ... | [
"Even though chips are small, they operate fast enough that the speed of electricity comes into play.",
"Signals sent from one part of the chip to the other end can actually take measurably long to travel, so if you don't sync state across the entire chip, you might be doing two operations like adding 4+7 and 9+3... | [
"If you are computing a digital result, you need to give a definite answer, i.e. 0 or 1. Circuits can stay for a time in intermediate \"metastable\" states somewhere between 0 and 1. With a synchronous clock, you can arrange for all parts of the circuit to have settled before the next tick. But if you want to desig... |
[
"What reaction produces the heat in hot oil treatments for hair?"
] | [
false
] | The directions say to put it in warm water before using, but I never do and it's still heats up during use. | [
"There's some moisture in the skin on your head that would probably activate it as well. "
] | [
"My guess is that if feels like it is heating up because it is making it hard for you scalp to sweat. If you list the ingredients i can give you a more definitive answer."
] | [
"There are lots of compounds that react exothermically with moisture. Some googling says that commonly used ones for cosmetics/hair care are polyethylene glycol, magnesium sulfate, aluminosilicate or other zeolites, calcium chloride, etc. Look at the ingredients list."
] |
[
"What stops viruses such as ebola/the plague from infecting humans at an earlier point?"
] | [
false
] | [deleted] | [
"Im not sure what you mean by 'the plague'. If you mean the bubonic plague, it is not a virus but a pathogenic bacterium that causes it and it did infect humans earlier. There was the Black Death of the 1300s and earlier epidemics as well, for instance one which likely contributed to the Roman Empire's collapse. ",... | [
"Ebola actually isn't actually a very evolutionarily fit virus in humans... It's really scary because of all of the awful things that it does to those infected, but it takes effect so quickly, that when someone gets sick, they are often quarantined fairly quickly, and their bedsheets and clothes are disinfected som... | [
"The thing with horrible viruses like Ebola is that they are TOO good at killing people. If you have a virus that kills someone really fast, how does that virus get spread to other people? It'll be like hijacking a car and crashing it right away. It would have been better to hijack a car, pick up your buddy with it... |
[
"I can't find a simple definitive answer for this on google. Is matter fundamentally made up of energy?"
] | [
false
] | null | [
"Energy isn't a substance that things are made of. It's a quantity. Matter has energy."
] | [
"Yes.",
"No."
] | [
"I believe that the poster is asking this question in reference to Einstein's classic equation E=mc",
" .",
"I am also curious about this since mass can be converted into energy through nuclear reactions. How are mass and energy linked below the particle level? Are they the same thing at a low enough level?"
] |
[
"Curved trajectory of Ping-Pong balls."
] | [
false
] | Most sport balls which exhibit curved trajectories (baseballs, wiffleballs, tennis balls...) have non-spherical surfaces but not ping-pong balls. Could anyone shed some light on the source and magnetite of the curved trajectory in different sorts of balls. | [
"Adding spin to the ball will cause its trajectory to curve, due to the ",
"Magnus effect."
] | [
"A ball that's spinning is moving faster relative to the air on one side than on the other. Faster velocity is associated with lower pressure (bernoulli's principle), so this means that the difference in velocities creates a difference in pressure. And that means there's a force, which acts perpendicularly to the b... | [
"What trajectory are you talking about? If you throw a ball its trajectory is always curved due to gravity."
] |
[
"Does squeezing a soda bottle and sealing it keep it carbonated longer?"
] | [
false
] | why or why not? | [
"\"Fizz keeper\" is useless, since it only injects air.",
"While this might give a psychological effect later on (from the puff of escaping air), pumping air into the bottle has little effect on the partial pressure of CO2 in the space above the liquid. To keep soda from going flat, you ",
" pressurize it wit... | [
"\"Fizz keeper\" is useless, since it only injects air.",
"While this might give a psychological effect later on (from the puff of escaping air), pumping air into the bottle has little effect on the partial pressure of CO2 in the space above the liquid. To keep soda from going flat, you ",
" pressurize it wit... | [
"Indeed, by squeezing the air out, you will cause MORE fizz to escape the liquid, here is why:",
"Pretty soon the bottle is going to get pushed out to its original shape by the fizz leaving the liquid (I had a dumb roommate who always accused me of opening his coke bottles), and when that happens, the entire empt... |
[
"How do sea creatures stay hydrated?"
] | [
false
] | null | [
"Sea creatures stay hydrated by absorbing water from the sea, with the exception of marine mammals, which mostly get their water from the food they eat.",
"\nUnlike most land animals, most marine animals do not need large amounts of fresh water to deal with excess salt. Instead they have various mechanisms for sa... | [
"Would sea turtles be included in that exception?"
] | [
"Sea Turtles, like most marine reptiles and birds, mainly regulate salt in their body with their salt gland.\n",
"http://en.wikipedia.org/wiki/Salt_gland"
] |
[
"How do Venus Fly Traps hope to pollinate and germinate if it kills any pollinating insects (Like Bees) that come to it?"
] | [
false
] | null | [
"flytraps reproduce through rhizome formation until they are about 7 years old. Then they produce flower and seed. Its not like the plants going to snatch a bee that flys by...they only close...not chase. So landing on a trap...deadly...on the flower, once they form, totally safe. "
] | [
"Well first of all they build a very tall (",
"compared to their normal height",
") stalk on which to flower. Keeps the pollinators as far away from the business end of the leaves as possible."
] | [
"OP brings up a good point though. I wonder if any flowering carnivorous plants have mechanisms that repel pollinators from the dangerous bits."
] |
[
"How does the shape of a cat's pupil change the way it views the world? Is it even possible for us to know how they see?"
] | [
false
] | null | [
"UC Berkeley's Yang Dan did a study on visual encoding on various animals, a brief search will show some of her findings including a video of imaging through an implant on a cat's head although this doesn't answer your question. "
] | [
"I know you downvoted me because I'm not into animal torture. I just wanted you to know that I think harming other living beings for science makes science look cruel and backwards. I do perfectly fine livening cruelty-free so much so that I realize cruelty-free people are just fine without all the torture of living... | [
"I know you downvoted me because I'm not into animal torture. I just wanted you to know that I think harming other living beings for science makes science look cruel and backwards. I do perfectly fine livening cruelty-free so much so that I realize cruelty-free people are just fine without all the torture of living... |
[
"I've read that Antarctica is, in fact, an archipelago, but the concept of Pangaea seems to dispute this. How solid is science's understanding of 'Pangaea'?"
] | [
false
] | [deleted] | [
"Antarctica is a proper continent. It's just referred to as an archipelago in what you read because a sizable chunk of the actual land mass is below sea level (maybe because it's got a few miles of ice on top weighing it down). But underneath the ice is a continental plate like any other, that moves around like a... | [
"Ah, I think I understand the confusion. Antarctica is a land mass, not the ice that rest upon it. ",
"Map",
"This is a key distinction and why we have an Arctic Sea and not the Arctic continent in the north. Antarctica, the land mass, is part of the Pangea theory, not the ice.",
"As an aside, the poles are n... | [
"Ah, I think I understand the confusion. Antarctica is a land mass, not the ice that rest upon it. ",
"Map",
"This is a key distinction and why we have an Arctic Sea and not the Arctic continent in the north. Antarctica, the land mass, is part of the Pangea theory, not the ice.",
"As an aside, the poles are n... |
[
"Why do we often get the urge to jump off of high things? Has anyone ever researched this?"
] | [
false
] | Not sure how scientific you can get with a question like this, but it's worth a shot. | [
"The experience of a sudden urge to jump when in a high place has been speculated to be associated with suicidal ideation; however, scant data has informed this speculation. We termed this experience the high place phenomenon (HPP) and proposed that it stems from a misinterpreted safety signal (i.e., survival insti... | [
"L’appel du vide\nFrench – “The call of the void” is this French expression’s literal translation, but more significantly it’s used to describe the instinctive urge to jump from high places. \nFreud also called it the death instinct or death drive ",
"http://en.wikipedia.org/wiki/Death_drive"
] | [
"The first part of a question like this is to ask, do we often get an urge to jump off high things?"
] |
[
"Do Wind turbines reduce the speed of the wind, and if so, by how much?"
] | [
false
] | null | [
"Yes. Wind turbines extract energy from the moving air and convert it to electricity, so for energy to be conserved the energy (i.e. speed) of the wind must be reduced. You can see the effect in ",
"these",
" wind speed measurements from a wind farm, where wind speed was reduced by up to 50% in the wakes behind... | [
"For more information, see ",
"Mark Z. Jacobson's",
" publications. He published a lot on these and related questions at the intersection of wind turbine infrastructure and atmospheric science."
] | [
"This is a somewhat difficult question to answer. A wind turbine does reduce the energy of the wind for downwind turbines if they are the same type and the wind is blowing the right direction. However, tests show that turbines of mixed height can improve efficiency in some ways due to how the turbulence flows. Of c... |
[
"Is i < 0?"
] | [
false
] | [deleted] | [
"The concepts of less than and greater than don't really apply to complex numbers. ",
"You could have a complex number with a very large real part and very small imaginary part and a second with a very small real part and very large imaginary part. It's not obvious as to which number is larger than the other.",
... | [
"The complex numbers ",
" be totally ordered in a way compatible with their field structure.",
"Totally ordered",
"transitive relation",
"Compatible with the field structure",
"Here's the proof that the complex numbers can't be ordered in such a way: Suppose there was such an ordering. If i ≥ 0, then –1 =... | [
"The reals (and subsets of the reals- like integers) are the only numbers which can be ordered. ",
"Not true, you can also include infinite and infinitesimal numbers. The ",
"surreal numbers",
" are the biggest class of numbers you can order."
] |
[
"The end of a star."
] | [
false
] | I know that different stars "die" differently but some just turn into neutron stars, pulsars, and other types. My question Is what happens to these stars, are they still creating heavier elements or are they, or do they just last so long we dont know what happens to them? | [
"There's no more fusion. Either white dwarves or neutron stars are supported basically by the fact that the particles that make them up can't be squished together any more tightly. It's thought that after a very long time white dwarves will stop glowing and become black dwarves, but the universe isn't old enough fo... | [
"I thought that the star is constantly pushing elements together, so even if the molecules are packed together there still billions of molecules aren't they still being smashed into each other?"
] | [
"There are no molecules in a star. Molecules are made up of atoms linked together by electrons they share. White dwarves contain atoms that they are too light to fuse together, and neutron stars are, like their name suggest, basically a huge ball of neutrons compressed together by gravity.",
"So no molecules ther... |
[
"Is a non-hydrogen based star possible?"
] | [
false
] | [deleted] | [
"Stars on other phases of their lives are mostly not composed of hydrogen anymore.\nSome types of red giant stars has consumed all of it's lighter fuel, and it's burning other elements, mostly helium.",
"Look up Red clump and Stellar Evolution on wikipedia. Good read.",
"Heavy elements, up to Iron can be found ... | [
"A lot of the commenters so far have merely mentioned evolved stars, but those are not, in the main, \"primarily composed of heavier elements\" - whilst their ",
" composition can be H-poor, the surrounding envelope (which makes up most of the star, and of which the inner parts may be fusing) is still H-dominated... | [
"That's a good question. This is one of the most interesting aspects of stellar evolution, actually.",
"I'll start from the beggining.\nWhen a star is fusing hydrogen, it's in a balance between it's gravitational force (pulling mass to the center of the star) and it's nuclear fires (outward 'push' by nuclear fusi... |
[
"Where does water come from?"
] | [
false
] | I heard it came to earth from comets. Is that right? That seems like a LOT of comets. How come the moon didn't get any? (and for that matter, why didn't it get an atmosphere and life?) And how was it formed into comets? Do bubbles of hydrogen and oxygen bump together to form ice in space? My questions even seem ... | [
"The only silly questions are the ones you never ask! ",
"The water in the solar system mostly came from the molecular cloud that the solar system formed from. A large proportion of the water in the solar system is older than the sun! ",
"The water on Earth did mostly come from impacts of both comets and as... | [
"Thank you very much. One final question. What was so different about the moon from the earth, that we got the atmosphere and to keep the water, and it didn't? "
] | [
"So the moon kind of looks big in the sky because it's really close. But it's actually only around 1/4 the diameter of the Earth. ",
"The force that the gravity of one body will exert on another is a function of its mass; and, assuming equal density the mass is a function of its volume. But the Earth is also mo... |
[
"Do magnets lose strength over time?"
] | [
false
] | Will a magnet lose some of it's magnetic pull over time? | [
"Magnets lose an unsubstantial, negligible amount of \"pull\" over time. A typical permanent magnet will lose fractions of a percent of strength over many years. Other things that can ",
" cause a magnet to lose strength:",
" We call it the Curie temperature, but that's not the best way of looking at it. As the... | [
"Yes. The magnetic field exists because the dipoles in the magnet are all aligned in the same direction. Over time, blunt impacts may dis-align some of the dipoles; heat will cause them to vibrate out of alignment, or the presence of a different magnetic field may cause them to dis-align. ",
"Over time, the ordin... | [
"Demagnetisation due to temperature will be pretty rapid, though it will depend on your material. If you're using another magnetic field, the time scale will depend on the strength of the applied field, but basically instantaneous. I have no idea about shocks.",
"I can't speculate on the time scale of room-temper... |
[
"If sound is generated by vibrations in the air, would things sound different if we were surrounded by a different gas?"
] | [
false
] | [deleted] | [
"Yes. If you have a lighter gas then the speed of sound changes, so at the same frequency wavelength becomes longer. This in turn makes a difference in resonant frequencies, which happen when the size of a resonant cavity is an integer multiple of wavelength.",
"If your resonant cavity is the human body, then the... | [
"But assuming we're surrounded by a different gas, then that would change the sound generation, therefore changing the sound itself, right?"
] | [
"This changes sound ",
" - the mechanics of it, like what size your bass enclosure ought to be - but doesn't change sound itself."
] |
[
"What is the the irradiance (W/m^2) range of human vision?"
] | [
false
] | I’ve been putting something together that should graphically represent what an expanded human vision would look like, and while I have one axis (visible spectrum of 380nm to 700nm in wavelength) I’m not sure where the other axis falls, let alone how to directly convert lux to (W/m The closest I can find is two with the... | [
"Going off this",
", nine photons in 100 ms at 510 nm is sufficient for people to see, which is 90 photons per second, or 3.5e-17 W. Pupil is about 8 mm across, so that's 5e-5 square metres, so on the order of e-12 W/square metre at the lower end. ",
"Keep in mind our sensitivity to different wavelengths is dif... | [
"Researchers a few years ago discovered that humans can see single photons. ",
"Here we report that humans can detect a single-photon incident on the cornea with a probability significantly above chance. This was achieved by implementing a combination of a psychophysics procedure with a quantum light source that ... | [
"Oh cool! Last I read is that our eyes could detect a single photon, but our brain would filter it out, good to know there's been progress in this! Being a single-photon detector is a cool flex."
] |
[
"Every now and then, I hear a tingling noise (like a TV turning on) near the bottom back of my skull. What causes that?"
] | [
false
] | null | [
"Likewise, this has been happening to me for about as long as I can remember (early childhood), I'm almost 30 now, though it hasn't happened in a while. Also, it only ever lasts about 10 to 20 seconds, then slowly fades into silence. Don't take any drugs, or drink alcohol. In very good health according to my doc... | [
"Likewise, this has been happening to me for about as long as I can remember (early childhood), I'm almost 30 now, though it hasn't happened in a while. Also, it only ever lasts about 10 to 20 seconds, then slowly fades into silence. Don't take any drugs, or drink alcohol. In very good health according to my doc... | [
"Is this not normal? Haha I've experienced it my entire life. I've never even put thought into because I thought it was just one of those things that happens, but most people on here seem concerned for you. "
] |
[
"Is the sum total of biomass on Earth increasing?"
] | [
false
] | null | [
"This is a misconception; energy is used in this way to decrease entropy; chemical reactions do never change the mass of the reagents.",
"That said, i believe it is safe to say that yes, depending on how you count biomass (dead wood anyone) biomass increases as plants process minerals, and decreases as dead mater... | [
"This is a misconception; energy is used in this way to decrease entropy; chemical reactions do never change the mass of the reagents.",
"That said, i believe it is safe to say that yes, depending on how you count biomass (dead wood anyone) biomass increases as plants process minerals, and decreases as dead mater... | [
"This is a misconception; energy is used in this way to decrease entropy; chemical reactions do never change the mass of the reagents.",
"That said, i believe it is safe to say that yes, depending on how you count biomass (dead wood anyone) biomass increases as plants process minerals, and decreases as dead mater... |
[
"Is There A \"Critically Damped\" Equivalent for the Universe?"
] | [
false
] | OK, my understanding of the damped oscillator is there are three possible configurations: In an overdamped system the oscillator doesn't oscillate. It just decays to the minimum energy point. In an underdamped system the oscillator bounces back and forth around the minimum energy point, while the amplitude of the osc... | [
"This is called the critical density (and is calculated as ~10",
" kg/m",
" and the end result is still a heat death. Basically (ignoring dark energy), the Universe is currently expanding, but gravity is slowing the expansion down. If there is a large density of mass, it is enough to completely stop and then re... | [
"Big Rip needs an increasing dark energy density speeding up the expansion. It is none of the scenarios discussed above, and it is a very unlikely future."
] | [
"This is one of the fundamental questions at the heart of determining the \"",
"shape of the universe",
"\".",
"General relativity (GR) models the universe as curved spacetime, and this theory models our astronomical observations so precisely that it is reasonable to believe that curvature of the universe doe... |
[
"Is it possible to design a lens that has no spherical aberration?"
] | [
false
] | A parabolic mirror can reflect all incoming rays parallel to the optical axis to a single focus. Is there an analogous geometry for a lens that can do the same, at least for a single wavelength of light, so that spherical aberration is not a concern? | [
"Yes. In fact you can make a lens with spherical surfaces (which are easy to fabricate), which nearly eliminates the \"third order\" sperical aberration. Its called a \"best form lens\". There will still be higher order spherical aberration, but typically those are small to begin with. In general, aspheric lenses c... | [
"Yes, there are aspheric lenses that get completely rid of spherical aberrations. However even with those you can not focus down to a single point. This is due to the fact that ray optics are only an approximation, that falls flat close at the focus. \nWith aspheric lenses and monochromatic light you can in fact co... | [
"One way to look at ray optics is to understand them as an approximation of Gaussian optics far from the 'waist' aka focus of the beam. ",
"In Gaussian optics the width of a beam is predicted to be proportional to sqrt(1+(z/z0)",
" where z is the distance from the waist and z0 is called the Rayleigh range and d... |
[
"Why did it take so long to discover the first pulsar?"
] | [
false
] | I recently read that the first pulsar wasn't discovered until 1967 by astronomers. Since we have been staring at the sky for millennia, and as far as I understand, we can see a pulsar's blinking light with the naked eye (with a telescope), are there any good explanations out there for why we took so long to find one? | [
"Optically, pulsars look like normal stars. ",
"First, their rotation causes pulses in the radio-wave spectrum, not in the visible light one.",
"Second - Persistence of vision. They often rotate hundreds of times a second, which would be often much for a naked eye to see anyway. Remember video at is a 24 i... | [
"First, their rotation causes pulses in the radio-wave spectrum, not in the visible light one.",
"This is false, the Crab Pulsar pulses in visible light. So, do all pulsars - all the way from radio to x-ray. That's what makes it a pulsar.",
"Second - Persistence of vision. They often rotate hundreds of times a ... | [
"Pulsars are Neutron stars, which have no intrinsic brightness. Instead they generate electromagnetic waves in interactions of protons and electrons in the strong magnetic fields at each poles. This process creates light at all wavelengths. However, while the radio wave pulses are stronger than most other radio sou... |
[
"What direction will a photon travel in?"
] | [
false
] | Massless particles in a vacuum must travel, C, the speed of causality (and light). Ok. However, what gets me is the direction the photon is traveling in. In order to travel at C it must have to choose a direction. We typically think of photons and light having momentum in a certain direction (for example the sun's phot... | [
"The momentum p of a photon (and also every other quantum particle) is related to its wavelength lambda by the formula p=h/lambda, where h is Planck's constant. So if the momentum goes to zero, then the wavelength goes to infinity. ",
"Now what does this physically mean? Light is just an oscillation of the electr... | [
"However, imagine a newly created photon with no momentum (in terms of direction). ",
"a photon can't have zero momentum. ",
"if you assume it can (which the whole rest of your post does) you are bound to get \"violations of physical principles\". "
] | [
"Here's a system with no momentum, that's about to produce some photons: positronium: an electron and a positron (anti-electron) in orbit around each other. ",
"Soon they will annihilate, and become pure electromagnetic energy. When they do, though, they create ",
" photons, traveling in opposite directions.",
... |
[
"Driving over broken glass; better to go fast or slow?"
] | [
false
] | On one of the roads that lead to my work's parking lot there is often broken glass on it. Usually just broken beer bottles. Unfortunately, there is sometimes no way to drive around or take another road. There's a debate in my office whether it is better to driver fast or slow over the glass. Those that drive fast sa... | [
"Going faster will kick up the glass and you'll be more likely to get it caught in your CV boots and cut those up, so I'd drive slower.",
"Car tyres are pretty thick, I've run over beer bottles that someone put behind my wheels with no issue."
] | [
"As far as actual damage to the tires goes, it shouldn't really matter which speed you drove over the glass. The same amount of your tire will touch the road regardless of the speed that you drive over it.",
"What would matter is the size of the glass pieces and their orientation. If the piece was long enough tha... | [
"If people are regularly throwing beer bottle onto your road in the same place, you should consider contacting your local police department. Perhaps they would send out officers to witness and charge these people. At the least throwing bottles into a road is rude, if not illegal."
] |
[
"If I ate a malignant cancerous tumor, does that increase my risk of getting cancer or is the genetic material destroyed by digestion?"
] | [
false
] | null | [
"Very unlikely. Setting aside what would ever possess you to do such a thing, If any malignant cells were to reach your bloodstream, they wouldn't last long. ",
"Your immune system recognizes cells from another individual as foreign, and destroys them. This is what happens in ",
"graft rejections",
". ",
"T... | [
"They have actually injected malignant cancer tumours from one person into another person, and the cancer does not take hold in the second person. From back in the day before they had things like \"informed consent\" and research ethics hadnt been well established."
] | [
"People have gotten cancer from transplanted organs from someone who unknowingly had cancer. So you can transfer it from person to person, however, it's only possible in this instance because we take immuno-suppressing drugs for transplants to suppress the immune-system, which then can't destroy it. ",
"So if yo... |
[
"Why does electricity usually spread itself in a zig zag pattern when there's no concrete path to follow?"
] | [
false
] | null | [
"I assume you're talking about things like lightning. Ordinarily, air is extremely resistive to electrical current flow. But, when the electric field is strong enough, a narrow channel will ionize and conduct current. This allows charge to advance a short distance, where the electric field builds up again, causi... | [
"lack uniform conductivitry",
"Incorrect. Lightning does not follow a pre-existing pattern of weakness. Instead it's an example of ",
"dendritic growth",
" a natural fractal, similar to watersheds (macro) and percolation structures (micro.)",
"I've noticed that older textbooks still claim that lightning... | [
"lack uniform conductivitry",
"Incorrect. Lightning does not follow a pre-existing pattern of weakness. Instead it's an example of ",
"dendritic growth",
" a natural fractal, similar to watersheds (macro) and percolation structures (micro.)",
"I've noticed that older textbooks still claim that lightning... |
[
"How do these new robotic prothetic arms work?"
] | [
false
] | More specifically: I always understood that the size of the brain was relative to the size of the creature's body--that is, the more mass you had to control, the more brain mass you needed to control it. So how do the new prosthetic arms work? On the Colbert Report a while back a guest was on who wore a third arm on ... | [
"I don't study this specifically, but I have followed Nicolelis' work in the past, who focuses on neuroprothesis- or brain-computer interfaces. One thing to understand is that for every movement- let's say lateral movement of the arm- isn't coded by only one neuron. There are populations of cells that can engage a ... | [
"http://www.colbertnation.com/the-colbert-report-videos/269864/april-05-2010/dean-kamen",
"Maybe this isn't the best example, but I thought there was technology out there--a neuroscientist was on the Daily Show last night to talk about it--where monkeys can control video games or robotic arms with only their mind... | [
"It's different, if those nerve endings are still active it's possible to connect a chip between the nerve endings and the prosthetic. This can trigger air muscles/mechanical devices in the prosthetic to react to the electrical signalling induced by the user. So the arm isn't connected to the brain but the nervous ... |
[
"would a container with a vacuum in it float?"
] | [
false
] | [deleted] | [
"Yes. If you could create a light container with a vacuum inside it that won't collapse under atmospheric pressure, it will experience more buoyancy than helium or hydrogen filled things do. It would be very hard to create that type of container though."
] | [
"I would have loved to see it come up off the rails just before the implosion."
] | [
"I would have loved to see it come up off the rails just before the implosion."
] |
[
"To what extent is the Standard Model \"all math\", with any physicality being just an analogy with macroscopic phenomena?"
] | [
false
] | null | [
"Can you explain what you mean by that?"
] | [
"I can try. My question is: What is the extent to which the fundamental units of study at the smallest scale of physics are best regarded not as physical entities (and related dispositions to act) which behave in accordance with certain mathematics, but instead are best regarded as purely mathematical constructs,... | [
"The Standard Model of particle physics is a mathematical theory, but it’s meant to describe real physical things. So it’s not “just math”. I’m not sure what you mean about a “universal substrate”."
] |
[
"What is preventing tidal energy generation from being a ubiquitous source of energy for cities near the ocean?"
] | [
false
] | I live in a beach town in California and I was just wondering why we don't get some energy from the ocean. I know there are mechanisms to extract energy from the tides so what's holding it back from becoming widespread? | [
"They are working on it.",
"In NYC's East River, a third generation turbine is under development.",
"The first was destroyed by the current.",
"Pretty sure there is a project in Maine too.",
"I'm sure there are more, but it is in its infancy."
] | [
"Harvesting energy from the tides takes energy from the Moon's oribit around the earth. This is not a renewable resource. When we deplete the moon's oribital energy, it will crash in to the earth.",
"First, the Moon drifts away at ~4cm/year due to tides. That energy is coming from Earth's rotation.",
"Second, i... | [
"Harvesting energy from the tides takes energy from the Moon's oribit around the earth. This is not a renewable resource. When we deplete the moon's oribital energy, it will crash in to the earth.",
"First, the Moon drifts away at ~4cm/year due to tides. That energy is coming from Earth's rotation.",
"Second, i... |
[
"What is Dissociative Identity Disorder and what are some other ways the brain copes with trauma?"
] | [
false
] | There are many books and internet sources about these things but I decided it would be much shorter in description (not an essay) if I simply did an askscience. What I do know about DID is that it is on the road to Multiple Personality Disorder. That is pretty much all I know though. | [
"As a panel we've discussed this and feel it's perfectly appropriate as these diseases and branches of science have definable, objectively measurable results and information. I think it's for the best if we let one of the panelists on this subject determine and answer for this one. "
] | [
"Dissociated Identity Disorder (DID) ",
" Multiple Personality Disorder. The name changed almost 20 years ago.",
"OK, so the concept of DID is that there are 2+ distinct personalities going on inside the person. When one of the personalities is dominant, the other personality will later have no memory of what w... | [
"DID is defined as \"the presence of 2 or more distinct identity or personality states\". It's also what MPS is now called. Source: Diagnostic and Statistical Manual of mental disorders, fourth edition (DSM-IV)"
] |
[
"A question about quantum entanglement"
] | [
false
] | So in quantum entanglement we have two particles where by measuring one, the state of the second particle is instantly determined, implying that information about being measured travels faster than light. But how do we know that it cannot be that entangled particles always enter any state A or B that are exclusive to o... | [
"Bell's Theorem",
"Hidden Local Variable Theory",
"This has been asked many times before, please use the search function in the future."
] | [
"You are very right that we cannot send information faster than light. People who claim otherwise are mus-representing science. But, the reason doesn't come from your original point. ",
"We know that the particles do not have a \"true state\" until they are measured due to Bell's Theorem (Well, we know that unles... | [
"Quantum information would only really travel faster than light if we could successfully manipulate one particle to always enter one of two states which would be mirrored by its twin, making FTL morse code possible.",
"Exactly. Which we can't. This is the reason you can't just quantum entanglement to transmit inf... |
[
"Why doesn't light emitted radially from inside the event horizon of a black hole escape?"
] | [
false
] | Here's what I think I know (Please tell me if I'm wrong): Photons are not affected by gravity directly. Their direction changes due to the bending of space-time caused by mass and energy. So, it doesn't make sense to think of a photon emitted radially from a star as a bullet from a gun since photons don't slow down and... | [
"Inside of the event horizon of a black hole, there is no direction that one can travel that leads to outside of the event horizon. Space-time is warped in such a way that every single direction you can point in leads to the singularity at the center of the black hole."
] | [
"Photons are affected by gravity as \"directly\" as anything else. They follow shortest-distance paths in curved spacetime, like any other particle. That's exactly what gravity is!",
"You're right that the ",
" around a (non-rotating) black hole is uniform - radially symmetric, to be exact, which is to say that... | [
"RobotRollCall, is that you?!"
] |
[
"At what size do we switch from making predictions through quantum physics to Newtonian laws?"
] | [
false
] | I was reading a book which discussed the buckyballs double slit experiment. It used a brick wall and soccer balls as a metaphor. It mentioned that at some point a switch has to be made as the outcome with actual soccer balls differs from interference pattern witnessed with buckyballs but it did not specify. Have we det... | [
"Molecules of all sizes obey quantum mechanics, but as the system gets larger quantum mechanics limit to classical mechanics. Since systems in daily life (such as soccer balls) are made up of a number of atoms on the order of avogadro's number (~10",
" ) there's essentially no difference between the classical an... | [
"Would it be accurate to imagine that the face that a macro entity is comprised of so many quantum-level interactions that they average out into a final observable outcome, whereas a single quantum-scale entity still exhibits randomness?"
] | [
"That is a very accurate way to think about it."
] |
[
"The true length of an inch, weight of a pound, (and other measurements)?"
] | [
false
] | I watched a short video explaining how the gram was derived. It explained that there is a silver (or metal) cylinder locked in the vault of a European agency, and is the only object in the world that truly weighs 1 gram (most things weigh 1.000001 grams, for example). It's apparently a critical object for continuity ... | [
"Many constants are actually taken from nature. For example 1 meter is defined as the distance light travels in 1/299,792,458 of a second. A second on the other hand is defined by the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state... | [
"It is similar with other constants, like force.",
"Except that the SI unit of force is the newton, which is a derived unit equal to 1 kg m / s",
" .",
"So the units of force depend on the kg, which is defined by the actual \"international standard kilogram\" in a vault in Paris.",
"(And, OP, the standard o... | [
"It should be noted they aren't \"taken\" from nature, they are created arbitrarily from humans, and then hundreds of years later they were reworked into using the speed of light or periods of radiation.",
"For instance, if the original \"meter\" stick was slightly longer, then it would actually be defined as 1 /... |
[
"EMF Neutralizer? Help me scientifically debunk this."
] | [
false
] | My fiance brought home this product: It says that it neutralizes the EMF from a cell phone, but it's just a little sticker. If the product really worked, wouldn't it need to cover the whole cell phone? I don't know a lot about physics, but maybe one of you can help? | [
"It's total nonsense. Absolute, shameless, nonsensy nonsense. For so many reasons.",
"First, as you say, it's just a little sticker. Even if it did block EM radiation in one direction from one place (which it almost certainly doesn't really), there's plenty more going in all the other directions.",
"Before even... | [
"Not only is the whole premise of the sticker blocking radiation wrong, as mmypig pointed out, the whole idea the emf from cellphones will have any significant effect on you is bogus. Cellphones do not emit enough energy to physically heat your brain, and with regards to ionizing chemicals and cells and stuff, I di... | [
"Dutch tv had a part on a similar scam; they were LED lights in a box filled with sand they sold for some 1000 euros. I asked my power electronics professor about the risks and harm of large electromagnetic fields (also because I remembered him saying he oncestood near an Ampérage soo high that it actually heated h... |
[
"Why can't you enter a hyperbolic trajectory around a black hole, within the event horizon?"
] | [
false
] | Been thinking about this. If you have velocity going in, why can't you swing through the event horizon and back out to an escape trajectory? | [
"You're still looking at a black hole in the classical sense, as only a source of some sort of force. It's not entirely accurate, and it's the very reason for your confusion here. Gravity isn't just some force applied by massive objects - it is a curvature of spacetime. In black holes, it bends spacetime in such a ... | [
"At the event horizon, the gravitational pull is so strong that even photons emitted radially outward from the black hole will still fall in, and they travel at the speed of light. No amount of velocity, even the speed of light, is sufficient to overcome the gravity of a black hole at the event horizon. It is not t... | [
"For objects orbiting a massive point-like body in Newtonian gravity the effective (repulsive) centrifugal force, that goes like r",
" , always overcomes the gravitational force, that goes like r",
" , when the object is close enough (unless the object's angular momentum with respect to the body is zero), so th... |
[
"How do flu/cold viruses survive lockdown?"
] | [
false
] | I live in New Zealand where the coronavirus is nearly eliminated because of the lockdown. However we are being advised to get flu shots. How is it that the lockdown eliminated covid but not all the other cold/flu viruses (which have a lower R naught value)? Where are the viruses being introduced from if no one is enter... | [
"Animal transmission and long-term surface transmission do occur, also some people manage to not beat an illness in the average time and stay a carrier longer than average, but the easiest example is also the simplest. Even under lockdown some portion of the population is still required to do work and move around ... | [
"Dont forget that Covid-19 cases will be tracked and quarantined, cases of cold and many flu cases won't be. So I'd assume that the rates of cold and flu go down as well, but they are not the targeted diseases and will thus survive. I currently do have a mild cold, live in Germany and noone would even remotely cons... | [
"Just got my flu shots a couple of weeks ago. Talking to the doctor about whats been happening over isolation. She said it should be peak flu season at the moment, in Australia, and they are almost seeing no cases. So it does seem to be slowing infection. As an aside there has been a push in Australia, in the last ... |
[
"In explosive shockwaves, like the Beirut explosion, how thick is the propagating shockwave itself?"
] | [
false
] | null | [
"How thick is the ",
" I had to mull this question over because we generally model shockwaves, to low precision, as instantaneous or discontinuities in the air pressure because the shock is moving supersonically. The ramp-up from ambient pressure outside the of the shock to the overpressure/shocked air inside is ... | [
"Yeah, I left my post a bit vague because I'm not a fluid dynamicist so I don't have codes like that handy. I was hoping to bait someone into actually running something like you just described.",
"What metric related to pressure would you intuitively use to characterize the shockwave size?",
"Literally exactly ... | [
"The question could mean a few possible things. To start, a shock wave has four regions to consider: ambient air in front of the shock wave, a short transition between ambient and shocked air, an above-ambient pressure zone following the shock, and a below-ambient pressure zone that arrives last.",
"The easiest w... |
[
"Do matter and antimatter collisions break the rule of law of conservation of mass?"
] | [
false
] | My understanding is that when matter and antimatter collide, they annihilate each other. Does this mean that the matter is completely removed from existence or is it transformed like how it's defined in the law of conservation? | [
"Conservation of mass holds in nonrelativistic physics, but not in general. Processes that violate conservation of mass (like annihilation, or just the existence of antiparticles) are therefore exclusively relativistic phenomena. Indeed, annihilation produces photons, which are definitely particles in the relativis... | [
"Relativistic mass = very bad. Very very bad. Use invariant mass.",
"In the nonrelativistic limit (i.e. expanding in v/c) the relativistic energy E = m γ c",
" becomes the Newtonian kinetic energy mv",
" / 2 plus a very large constant energy E0 = mc",
" , rest energy. This term is constant in Newtonian mech... | [
"The way I explain this to my High-school Physics students is that it's not as simple as conservation of mass, it's more accurate to talk about conservation of energy, and think of mass as energy using e=mc",
" Is that too much of an oversimplification?"
] |
[
"Is there such a think as an Immunoglobulin (Gamma) inhibitor, or someother type of drug that can help your body reset its over-reaction to common allergies?"
] | [
false
] | null | [
"There is exactly this, ",
"rituximab",
", and it does cause massive, devestating global effects. It is used in B-cell lymphomas and occasionally in autoimmune diseases like neuromyelitis optica.",
"Keep in mind that allergies are IgE mediated, not IgG."
] | [
"Understanding that if there is, this drug would most likely inhibit all IgG and thereby having massive, devastating global effects. "
] | [
"Yes, but it's just like a blood transfusion."
] |
[
"[Biology] Vampires and the sort are depicted as deathly photophobic. Are there examples of equally photophobic organisms in the real world? If so, what advantages do they get from this seeming handicap?"
] | [
false
] | null | [
"An immediate example I can think of are earthworms. I’m sure there are others too. Earthworms spend the majority of their lives underground, and as such do not have a need for the extent of protection from UV as above ground organisms need. When earthworms are exposed to the sun, they try very hard to get out of i... | [
"Queen bees of ",
" inside a hive avoid the light because it means they are no longer in a safe place. Except when mating or flying with a swarm the queen should never be in a place with light, the inside of the hive should be dark. As beekeepers when we pick up frames a look for queens its not unusual to see the... | [
"I thought the death blow for worms came from drying out rather than UV damage. Although technically, the sun still causes the death. So, thinking out loud, this means one general mechanism for death is for the heat to removes/destroys a protective coating.",
"Another mechanism I could imagine is that the sun ca... |
[
"Even if a virus doesn’t provoke a (noticeable) immune response in asymptomatic people, why don’t the deaths/lysis of the hijacked cells cause severe health effects in and of themselves?"
] | [
false
] | null | [
"Viruses don‘t necessarily cause cells to die, or go into lysis. Bacteriophages do that, but as the name suggests, they affect bacterial cells, not Eukaryotes. ",
"Ebola is a virus that causes cells to die and burst, which makes it so lethal. ",
"On the whole, though, a virus has no interest in killing its ho... | [
"Asymptomatic infections ",
" create damage and it's a very real problem.",
"For example, it's a concern that there are observed, enduring differences/abnormalities in the lungs of even asymptomatic COVID-19 convalescents that could greatly complicate future treatments, e.g. here in radiation therapy for certai... | [
"Great info, thanks! I thought (incorrectly) that infected cells were almost always killed, either by the virus or by the immune system itself —like how our bodies attempt to kill cells that are becoming cancerous.",
"I’ll have to read more about how infected cells can be told by the immune system to stop printin... |
[
"What in rubber's structure allows it to stretch?"
] | [
false
] | What is natural rubber composed of on a molecular level that allows it to stretch? | [
"There are a few things that give rubber some \"stretchiness\". Long molecular chains comprise the majority of elastic materials. However, long linear chains alone don't make something \"stretchy\". More often, they just make it viscous, like a bowl of spaghetti. However, adding a crosslinker, which connects long m... | [
"That's about right, but you got two things wrong.",
"Plastic deformation specifically refers to irreversible deformation, reversible deformation is simply called elastic deformation.",
"Elastomers have quite strong chemical bonds. They also have weak pseudo-bonds (usually hydrogen bonds) which cause them to fo... | [
"The other comments are correct - e.g. think tangled spaghetti, but a more interesting question is why does it want to retract again after straightening the chains? It turns out for many rubbers the chains are quite happy (heat energy wise) being stretched out , but still retract. There are two ways of thinking abo... |
[
"Do giraffes get struck by lightning more often than other animals?"
] | [
false
] | null | [
"So this is not my area of expertise and I hope other more qualified people chime in but I have found some informations (some of it even peer reviewed!). ",
"This article [1]",
" talks about how four legged animals are more vulnerable to lightning strikes because ground current has high chances to go through vi... | [
"Thanks for all of the info, guys. I posted this after waking up from a dream in which giraffes were being struck by lightning, of all things."
] | [
"It's also important to remember many of these (with the african elephant anyways, not sure about indian) are Savannah animals where there are rarely trees which come close to their height. I would imagine they would be like giant lightning rods"
] |
[
"Why does my glass cooking dish say \"preheated oven only\"?"
] | [
false
] | I would expect the gradual heating of the dish (i.e., from a cool oven) to be less stressful than going straight from 65F (or 35F if coming out of the fridge) to 350F+. So why does the dish recommend otherwise? | [
"Because your oven doesn't make the entire interior a certain degree evenly over time. There are these big things pumping massive amounts of heat into your oven and that is going to be much higher than what the over's set temperature is going to be, unless you have it set to the max of your oven, or it's self clean... | [
"So if I interpret that correctly, it's because the oven will be inconsistently heated, which can lead to local gradients in temperature that can cause nonuniform heating and expansion, cracking of the glass?"
] | [
"Most new pyrex dishes are in fact not pyrex. About 10 years ago in the U.S. borosilicate glass was suddenly allowed to be sold under the name pyrex.",
"Borosilicate glass is much less resistant to thermal shocks than real pyrex (but is a little more resistant to mechanical ones and breaks into safer peices).",
... |
[
"What industrial processes does current science suggest might be made possible or more efficient in a microgravity environment? How would space manufacturing change our material sciences and other areas of economic importance?"
] | [
false
] | I recently read a . I have heard that space manufacturing might be revolutionary for many industries - it's the for example - and I wonder how much of this supposed potential is backed up by actual science. In your area of expertise, what processes could you foresee being made possible or easier by the microgravity env... | [
"Manufacturing in space is still quite a long way away, simply because of the tremendous cost of bringing raw materials into orbit and finished products back down to earth. It's currently just not doable for economically significant amounts of materials.\nNevertheless, there are several experiments being currently ... | [
"Yes, space manufacturing is not anywhere near to being economically viable and I see no reason to assume that human beings will succeed in making it so. However, in the hypothetical that space manufacturing was taking place at scale, how valuable would the crystals without gravity defects be?"
] | [
"Unfortunately, I can't answer that question reliably. I am not involved in the experiments themselves and my knowledge of materials science is limited at best.",
"From what I have heard from a colleague who has worked on solidification, it entirely depends on your application: Sometimes, these defects are import... |
[
"Quantum Gaps in Big Bang Theory: a Problem with the Theory of Inflation?"
] | [
false
] | I read in Scientific American magazine today that basically the Big Bang theory must be replaced or fixed. The article said that the significance of the inflation problem is taken considerably lightly by most cosmologists. Why is this, if the gap in the theory is really as big as the magazine claims? | [
"Link to article please."
] | [
"They don't seem to post full articles on the website. Here's a link to what's available:\n",
"http://www.scientificamerican.com/article.cfm?id=the-inflation-summer",
"I read this article in the print edition. Here's a summary of how I understand it.",
"The flaw it's talking about is that, in standard inflati... | [
"I submitted the similar article twice. I need to run in a few minutes, but there's a pdf copy I saved and submitted to scribd in one of my submissions."
] |
[
"How is water pressure maintained to the top floors of buildings taller than municipal water towers?"
] | [
false
] | null | [
"The answer is kind of boring. The buildings have pumps. An old solution was to build a water tower on top of the building to supply at least the upper floors and New York City famously has hundreds or thousands of buildings with wooden water tanks on the roof.",
"More modern buildings, and especially taller buil... | [
"There certainly isn't a tank and a pump every floor. Exact code requirements vary from place to place but a typical range for supply pressure requirements is between 45 and 80 PSI. That difference of 35 PSI is a bit over two atmospheres or a little over 80 feet / 24 m of water head. So if you didn't have any press... | [
"That’s what’s so interesting though. You can’t draw the water more than 34 feet because of simple physics so you’d have to push the water upwards. Is there a water pump on every floor and a periodic buffer tank as well? The pressures and differences must be immense ",
"And like you say, there has to be restr... |
[
"Are African Americans with slave ancestry a different ethnicity than their contemporary western Africans?"
] | [
false
] | I understand that that this could be a sensitive topic, and I don't want to seem/be crass. Black people in the United States that have roots to slavery generally have a diverse and fused ancestry that goes back hundreds and hundreds of years and this isn't seen in Africans that are still in Africa. Is there a big enoug... | [
"I hear people say that \" Ethnicity is a social construct \", but I really don't think it is entirely true. My understanding is that Caucasian and Asian people have some Neanderthal DNA while Black people (people of pure African descent) do not. Isn't that a real difference?"
] | [
"While this is a good outlook that you should never change, there is some genetic proofs (different enzyme sequencing, minor muscular composition differences) that defines a difference in some ethnicities compared to others. "
] | [
"Race is based in DNA and physical appearance. Ethnicity is based in social and cultural similarities. By definition ethnicity is based on social /cultural groups not biology. "
] |
[
"Does earth's magnetic field affect electronics?"
] | [
false
] | I know that if you put a magnet near a flash drive it can erase memory, also near CRT moniters it can distort the picture but how does earth's magnetic field affect things? | [
"Static magnetic fields don't affect flash drives, which store data as charge on floating gates. They can affect hard disk drives however, as these store data in the magnetic orientation of bits. The magnetic fields in question are much stronger than Earth's, so it wouldn't have any appreciable effect.",
"In gene... | [
"Color CRTs can be affected by the Earth's magnetic field. The beams have to land on the correct phosphor dots, or the colors will be off. A degaussing coil is built in to color TVs and monitors to help erase any magnetism which the tube has picked up. ",
"http://repairfaq.cis.upenn.edu/sam/crtfaq.htm#crtnsh"
] | [
"Coronal mass ejections cause it to oscillate and this \"geomagnetic storm\" can affect radio reception, particularly AM and shortwave. A severe storm can damage power transmission equipment, radios, anything connected to a longish conductor. Long conductors become generators as the Earth's field oscillates across ... |
[
"Do we still think the universe is flat?"
] | [
false
] | I watched an older documentary last night, and they said using the WMAP satellite and high powered lazers they seen that the universe is flat. But some believe that its actually curved but its so big we can't tell that it is. Do we have any new evidence? | [
"Yes we do.",
"WMAP data showed to a great degree of accuracy (about 0.1%) that the universe was flat. From about 2009-2012 we had a similar, more advanced, satellite in operation called Planck. Like WMAP and COBE, it's predescesors, Planck made hyper accurate measurements of the cosmic microwave background. ",
... | [
"It isn't anything to do with planes, don't confuse flatness with 2-dimensional. ",
"An object in any number of dimensions can be flat or curved but because we live in a 3-d universe we tend to confuse what curved really means.",
"For example, a piece of paper is 2-dimensional but it is also flat, that much is ... | [
"There is a difference between flat geometry and 2-dimensional it has nothing to do with galaxies or stars being orientated in a certain preferred plane. What you are talking about is a 2-dimensional slice through the universe rather than the curvature of the universe which is a fundamental property. The universe s... |
[
"How can Helium be a liquid at absolute zero?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"This question is based on fundamentally flawed premises. Please conduct some background research and revise your question if you wish to resubmit.",
"The answer can be found with a Google/Wiki search.... | [
"That doesn't make any sense... ",
"You have a question on the main page right now: \"If mass is converted to energy in nuclear reactions, has the mass of the universe been decreasing since the beginning?\" where the answer is easily \"no\" if they did some \"background research\" and understand E=MC",
"Helium ... | [
"You have a question on the main page right now: \"If mass is converted to energy in nuclear reactions, has the mass of the universe been decreasing since the beginning?\" where the answer is easily \"no\" if they did some \"background research\" and understand E=MC2",
"Actually, the answer to that question is no... |
[
"Genetically speaking, why is inbreeding bad? What happens with the genes, why do mutations occur?"
] | [
false
] | null | [
"Mutation isn't the problem. The mutation rate is not any higher for inbreeding. You can look at inbred strains of mice (used in lab research). They have gone through 20 generations of first-degree relative mating, and yet they are perfectly healthy (for the most part).",
"The problem is that inbreeding increases... | [
"Each human being has their own sets of genes, good or bad. It is by luck if the bad gene or good gene gets expressed. In inbreeding if you have a recessive gene of lets say heart arrhythmia and your sister has the same recessive gene if you had a child together, the child would have both recessive genes for heart ... | [
"But humans get heavy deseases after one-two generations of first-degree incest. How come? Do we have more recessive genes?"
] |
[
"Aurora borealis/Aurora Australis are frequent on earth and noticeable from space. Has there been any instances of observing this on any other planets?"
] | [
false
] | null | [
"'Aside from Mars, all of the other planets which also experience an Aurora (both northern and southern lights) are those with active magnetic fields. And, because they have magnetic fields, their Auroras, like Earth, are majorly active on their poles.",
"The planets that we know experience Auroras in our solar s... | [
"An intrinsic magnetic field is not necessary for an object to experience auroras. But it helps concentrate them and make them more apparent. In addition to a weak magnetosphere induced by the solar wind, parts of the Martian crust are still magnetized from the dynamo Mars had billions of years ago. These magnetize... | [
"Auroras in general don't require the planet to have it's own intrinsic magnetosphere, but rather are the result of solar particles, accelerated by the solar magnetosphere, interacting with an atmosphere (and potentially another magnetic field). Fast moving charged particles from the Sun, and/or those that get trap... |
[
"What would happen if a human experienced zero magnetism?"
] | [
false
] | Would we just fall over? Could we even function or does Earth's magnetic field/magnetic forces even tie into a human's operation? | [
"If you mean the absolute lack of any electromagnetic fields, then it would get pretty weird. There would no longer be solid objects, for instance. All that stops you falling through the ground is electrostatic repulsion. And you can't have zero magnetic fields unless all the electrical fields go away too."
] | [
"You are, unfortunately, wrong. The electromagnetic interactions in solids are primarily attractive. the repulsive force that gives matter its stability- both in terms of avoiding self-collapse and also in terms of being impermeable to other solids- is electron degeneracy. If you need a source, here are a couple v... | [
"Serves me right for trusting my instinct without properly checking you claim. I learned something today!",
"Does the same argument apply to fluids, or is pressure there mediated electrostatically?"
] |
[
"Are dogs slowly evolving to the concept of language?"
] | [
false
] | Most owners talk to dogs, well and they have names. It seems that they can catch onto some of our language so doesn't that make our language somewhat useful to them in their lives in a way that would evolve to adapt it? | [
"If the ones selected for breeding are those that are smart and obedient enough to listen well to language, then language is an (artificial) evolutionary advantage. I imagine this isn't too common except for in certain \"designer\" elite breeds."
] | [
"If you mean human language, it's not very likely at all. We had large set of random physical adaptations that eventually lead to our vocal chords and a neural control system and muscles that could manipulate those vocal chords. Humans really lucked out in that regard. Then on top of that, there would have to be... | [
"Evolution requires a selective pressure:",
"People don't kill their dogs for being stupid and breed them for being smart (at least, most people don't).",
"There's no pressure for dogs to learn language, and creating one artificially probably wouldn't work."
] |
[
"Rust must be a major concern on seagoing ships. What technologies and techniques are used to prevent damage?"
] | [
false
] | I'd assume that regular painting would make sense, but are there specific kinds of paint for boats? Are ships primarily made out of rust-resistant materials? | [
"One strategy is to use a galvanic or sacrificial anode. Simply put, this is a chunk of metal more electronegative than the hull of the ship. When properly affixed, oxidation reactions will prefer the anode to the hull, reducing rust on the ship at cost of a non-structural and easy to replace chunk of metal. "
] | [
"The short answer, as you assumed, is paint.",
"Rust resistant materials would be very uncommon for for the hull and structure of large commercial ships such as freighters and tankers. Many smaller \"seagoing ships\", like fishing boats and mega-yachts have aluminum or fiberglass (FRP - Fiber Reinforced Plastic)... | [
"Many chunks of metal! ship's hull and interior beams are normally littered with these."
] |
[
"Is it possible for an ocean to be so deep that the pressure at the bottom turns it to ice?"
] | [
false
] | null | [
"Looking at the phase diagram for ",
"water",
", at 0 deg. C water has to be compressed to 632 MPa for it to change phase from liquid water to solid Ice VI. This won't be exactly the same for salt water, but it's a good point of reference.",
"Assuming water to be incompressible while liquid (not strictly tru... | [
"Yes! But I don't think it will happen on Earth.",
"Here is one physicist's take on the topic.",
"Here is a phase diagram of water showing how enough pressure will turn it into ice at arbitrarily high temperatures.",
"Here is a tool to convert between pressure and water depth.",
"It's also probably worth po... | [
"No, I don't think it would make any significant difference in this case. Deep ocean currents are around ",
"10 cm/s",
", so I don't think that would be a mechanism to prevent forming of Ice VI by compression."
] |
[
"How do water-based mammals hold their breath for long periods of time?"
] | [
false
] | I've heard whales can hold their breath for as much as 90 minutes. My question is simple. How do they do it? Is it larger lung capacity, do they use Oxygen more slowly, or do they intake a greater percentage of the Oxygen in their lungs on any given breath? On a secondary question, how do practiced humans hold their br... | [
"The only process in our bodies that requires oxygen is the breakdown of sugar to ATP. That said, the body can generate small amounts of energy anaerobically also. So, in large mammals, it is a mixture of a few things that make holding a breath for long periods of time possible. ",
"In humans, it is possible to i... | [
"Another factor is myoglobin, a protein of muscle that can also bind oxygen. Marine mammals have more myoglobin, which can store more oxygen and then release it when needed. Here is a description of the study:",
"http://news.nationalgeographic.com/news/2013/06/130614-diving-mammal-myoglobin-oxygen-ocean-science/"... | [
"the body can generate small amounts of energy anaerobically.",
"Considering a typical Sprint race, I wouldn't call that a \"small amount.\"",
"The main limitation to this is the body's tolerance for lactic acid buildup. Too much acid limits the ability of your blood to absorb oxygen in the lungs."
] |
[
"Is there a word for what the ocean is \"in\"?"
] | [
false
] | My kid asked me this question and after thinking a bit and a couple searches I couldn't figure out a definitive answer. Is there a word for what the ocean is in or contained by? Edit: holy cow, thanks for the responses!! I have a lot to go through and we'll go over the answers together tomorrow! I appreciate the time y... | [
"Probably the closest would just be describing it as being within a basin. Geologists commonly use the term \"ocean basin\" or \"ocean basins\" to refer to the low elevation area that contains the water within the ocean, especially in reference to processes that change the size or shape of these ocean basins (and t... | [
"This is correct: basin (geography) a great depression in the surface of the lithosphere occupied by an ocean"
] | [
"In common usage in the geosciences at least, the term \"basin\" without a modifier is much more generic and simply described a depression and by itself does not always imply that it is filled with an ocean (or even water). This is why we typically add a modifier, e.g., ocean basin, lake basin, sedimentary basin, r... |
[
"What is the science behind stale water?"
] | [
false
] | Why is it when I leave a a cup of water out for a couple days it tastes stale? I initially thought it was foreign objects such as dust and microscopic debris getting into it, so I covered it. But, I still taste the staleness. So, what's the deal? | [
"I'm assuming that you're talking about tap or spring water, not distilled water. So even if there are no foreign particles that enter the water after it is poured, there will still be some amount of bacteria in the water. So the taste comes from bacteria which multiply in the water over time. "
] | [
"If there is only water and other trace particles in the water, how are the bacteria surviving? "
] | [
"can also be from plasticisers leaching from bottles or cups etc, maybe reduction of dissolved oxygen in the water too due to the bacterial metabolism and also the metabolic waste may add to it."
] |
[
"Why is static electricity worse in the winter?"
] | [
false
] | Why do I seem to be plagued by static electricity in my clothing all winter, every winter? What factors make it worse? Why do wool sweaters always shock me? | [
"Dryer air. There is less humidity in the winter. I always have to ground myself before I put my earbuds in. Nothing like a static shock to the ear canal."
] | [
"A lot of the answers here talk about drier air, which is true. But there's a little more to that explanation. ",
"The air indoors is drier because cold air holds less moisture than warm air. When this cold air is then sucked into homes and heated, it has far less moisture than summertime air at that temperature,... | [
"In the winter the air becomes more dry (or less humid). Colder air has less ability to carry moisture around.",
"Water in the air helps to conduct electricity so when a charge builds up on something it can leak into the surrounding air and go somewhere there is less charge.",
"In the winter the drier air make... |
[
"Am I \"addicted\" to taking a shower, since I need one to feel awake in the morning?"
] | [
false
] | null | [
"Addiction is a state ",
"characterized by compulsive engagement in rewarding stimuli, despite adverse consequences",
". For the typical person, the daily shower has no adverse consequences and thus fails to meet the definition of an addiction. Furthermore, it is a stretch to call daily showering \"compulsive\"... | [
"That sample is skewed towards males. 24.6% of female responders showered at least once per day. 54.1% of male responders showered at last once per day. If you had sampled the population accurately (around 50% split of male and female), the norm would be less than once per day. Even the males alone are barely above... | [
"You're trying to define a term that doesn't exist in psychology/psychiatry."
] |
[
"How do we know black holes are 3 dimensional?"
] | [
false
] | Since our only method of viewing black holes is by using a telescope to view them from a stable point on earth, wouldn't we only be able to view black holes as two dimensional? We know planets and other celestial bodies are three dimensional because we can view light and other forces affecting them, but there isn't any... | [
"We can't see a black hole at all. It's black. We know they're three dimensional because they're the available solution from general relativity."
] | [
"Yes, all of its entropy is on the surface of the horizon. Since all of the information about the bh is on the horizon there is no interior. "
] | [
"And they come from collapsing stars, which are three dimensional."
] |
[
"Do animals have thoughts?"
] | [
false
] | Is there measurable evidence that we have what we describe as thoughts? Has this been found in any other animals? | [
"Depends what you mean by \"thoughts\" exactly.",
"Certainly animals can think. There are abundant examples of animals doing problem solving (some of it kind of remarkable). "
] | [
"Babies don't understand language or think in words until they develop an understanding of what words represent. And babies obviously have thoughts. They fake cry when they want attention, then check to see if they have garnered anyone's attention, and if not, they turn it up a notch. ",
"Any animal with a bra... | [
"Normal humans usually think in language and in words. Humans who have been raised without language typically never learn language and think in atypical ways. While we can never truly know what's going on in the mind of an animal, we might speculate that since animals don't have language they don't think in words a... |
[
"Cocaine use and dopamine down-regulation?"
] | [
false
] | What is the mechanism by which post-synaptic neurons experience down-regulation after chronic cocaine use? | [
"Sustained activation of the cAMP dependent pathway by the Gs protein results in the natural negative feedback mechanism, mediated by arrestins, to try to regulate the signalling.",
"In the presence of external agonists or higher then normal concentrations of the endegenous ligand, a neuron will continue downregu... | [
"Put in a different way:",
"The presynaptic neuron normally releases dopamine into the synapse, this activates receptors on the post-synaptic neuron. The dopamine is then taken back up into the presynaptic neuron, ending this signal. When cocaine is presence, the transporter that brings dopamine back up into th... | [
"Thanks for the response! ",
"Can you explain in simpler terms? I don't have a strong science background, and don't really understand very much of what you've so kindly written. ",
"What exactly is down-regulating? Does that refer to a decrease in the number of receptors?",
"Thanks again!"
] |
[
"Have beer and wine historically been as strong as they are today and if so, why have humans not developed a tolerance to alcohol?"
] | [
false
] | null | [
"Because that's not how evolution works. Since alcohol doesn't kill us, both people who are tolerant and people who aren't survive taking it and pass on their genes. Because of that, both exist to this day.",
"If, though, we spun 2 kinds of offspring, one which dies from alcohol and one which doesn't. The one tha... | [
"Technically this has already happened. In western civilisations the use of fermentation as a method to sterilise drinking water has been around for a very long time and is the reason western peoples (europeans, americans etc.) have a higher alcohol tolerance in general than asian people. This is because asian cult... | [
"I don't have a good source (maybe someone else does), but I've heard that this is ",
" of why native Americans (First Nations, etc., whatever the politically correct terms are these days) are so susceptible to alcoholism. "
] |
[
"Why do a lot of viruses/diseases seem to originate in the tropics?"
] | [
false
] | I have no factual evidence to support this, but it seems like a number of viruses/diseases originate in the tropics - specifically Africa. What causes this - beneficial climate, lower healthcare standards, different ecosystems? | [
"You must have misunderstood. I didn't say the illnesses were mosquito borne, I said they were spread by mosquitoes. And no, mosquitoes don't thrive in cyclic climates which are frozen for 9-10 months of the year the same way they do in the tropics. If the OP wants to go to wiki and read about the proliferation of ... | [
"Blood borne viruses that can be transmitted by mosquitoes tend to do well in hot humid climates, because bacteria and viruses as well as mosquitoes do well in those climates. They breed near warm shallow pools of stagnant water and marshy tropical forests are full of those. The more mosquitoes biting people , the ... | [
"I'm not exactly sure what your point is. Maybe I wasnt clear about the proliferation of bacteria and viruses in humid climates. Do you know what proliferation means? Do you have any info to provide the OP or just empty criticism for someone trying to answer a question?"
] |
[
"is there a relation between the wavelength of an electromagnetic wave and how easily can be assorbed?"
] | [
false
] | I was thinking that radio waves can't be assorbed by interstellar dust, something that visible light can't do, and gamma rays need a thick wall of lead, and that 5G is a shorter wavelength so it can be assorbed more easily, is there a correlation between wavelength and how easily can it be assorbed? | [
"There are a number of different process that could lead to photon absorption: photoionization, excitation to a bound state, vibrational or rotational excitation, nuclear absorption etc.. Absorption is thus highly dependent on what processes dominate and what kind of material is being considered (is it a metal? wha... | [
"Very much yes. Materials will tend to absorb some wavelengths of the EM spectrum more than others. These properties are highly material dependent, so wavelengths which are strongly absorbed by water may pass through glass. ",
"You can pick some common materials and google “absorption spectrum” to see exam... | [
"In the right ballpark. 100 MHz FM waves are actually 3 m or about 10 ft.",
"c/f = (3x10",
" m/s) / (100x10",
" or 10",
" Hz) = 3 m"
] |
[
"Origin point for thunder?"
] | [
false
] | [deleted] | [
"The sound originates from the lightning channel. Once the channel is formed, a high current runs through it. This current is what generates the light you see and while the channel is rather conductive, the current is high enough that a large amount of heat is also generated.",
"This heat causes a rapid expansion... | [
"Fun Fact:",
"\n1 Mile = 5280ft",
"\nSpeed of Sound = ~1125 ft / s",
"\nTime for Thunder to travel 1 mile = 5280 / 1125 = 4.7 = ~5 seconds. ",
":: When you ",
" the lightning, begin counting until you hear the thunder.",
"\n:: Every 5 seconds you count, the lightning is about 1 mile away!",
"\n:: Dis... | [
"Ionization of ions, each at its own relative speed, would produce its own effect, which includes not only the above mentioned but light itself, thus the proper order from fastest to slowest will be light, electricity, shock, sound, heat, smell. ",
"They should all come from the same source. ",
"Whether it is ... |
[
"What is the Color of the Sun: White or Yellow?"
] | [
false
] | I remembering hearing during a science interview that our sun's color is white instead of yellow. It only appears yellow because our atmosphere filters out the other colors. The reasoning they used was that if the Sun were yellow, then snow would appear as yellow instead of white. That reasoning does not have me con... | [
"Color is a bizarre, only quasi-defined notion -- it only loosely maps to the spectrum. Hence, there are several good answers:",
" both by contrast to the blue sky and because of scattering in the atmosphere. If you look at the Sun with neutral-density filters that don't affect the spectrum passing through them... | [
"Excellent answer. It boils down to the fact that white is not a thing, but a convention. There are many ways to call something \"white\".",
"Whenever I hear people asking questions like this about colors, I point them at the CIE diagram:",
"http://en.wikipedia.org/wiki/CIE_1931",
"To the OP: Look at that hor... | [
"The aperture (the \"entrance\") of the telescope remains unfiltered. The entire energy of the solar radiation enters the scope, and is made more dense (is \"focused\") on a tiny shard of glass or plastic screwed into the eyepiece (the filter). It doesn't take a PhD in rocket science to predict the outcome: the fil... |
[
"If everyone on Earth started running in the same direction, would it affect the Earth's rotation?"
] | [
false
] | (effect?) | [
"The total mass of all the humans in the world is ",
"4.2x10",
" kg",
". The mass of the Earth is ",
"6x10",
" kg",
". So humans weigh less than the Earth by a factor of roughly 10",
" . That's 10 trillion. This is the same ratio as the masses of a ",
"grain of sand",
" (10",
" kg) and a small c... | [
"Strictly speaking, just one person running has an effect on the earth's rotation - just an immeasurably small one. Same with the entire population. Our combined mass is too insignificant compared to that of our planet."
] | [
"Everyone jogging at the equator: ~10",
" Js",
"Earth's angular momentum: ~10",
" Js.",
"So no."
] |
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