title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"European colonists brought infectious diseases that killed a huge number of Native Americans because they did not have immunity. Did Native Americans also infect colonialists with new diseases? If not, why not?"
] | [
false
] | null | [
"Yes syphilis is thought to have come back together with a colombus expedition and it killed millions of Europeans, but of course people in other parts of the world as well. It is possible that it came to europe in another way but this seems to be the most probable theory. ",
"It never killed the majority of euro... | [
"Syphilis is the canonical answer, but it's also worth pointing out that the Native Americans did not have the range of diseases Europeans had, because their population density was too low. It's a bit like nuclear fission --- there's a threshold density (which depends on the disease) below which infections will fiz... | [
"TLDR:",
"While I enjoy CGP greys work his America pox videos is deeply flawed. For example smallpox and TB predate domestication and evidence of TB has been found in the americas dating as far back as 17,000 years ago. ",
"To quote from ",
"r/askhistory",
" ",
"The video in question is essentially parrot... |
[
"Why is Beryllium-8 Unstable?"
] | [
false
] | Helium-4 (an alpha) is super-stable. So is Carbon-12, which can be viewed as merely 3 alphas. So are Oxygen-16, Neon-20, Magnesium-24, as 4, 5, and 6 alphas, respectively. Each of these elements can be viewed as merely a pile of alphas, and all but Be are all stable, and given my limited, understanding of nuclear phy... | [
"This is an example of why you can't really rely on intuition in nuclear physics. It's true that the alpha particle is one of the most energetically favorable nuclides you can come up with, and it's true that nuclides which are \"multiples\" of alpha particles can often be modeled as interacting alpha clusters.",
... | [
"And high binding energy is, to at least some extent, a proxy for stability, no?",
"Not necessarily. Nuclear stability depends on many factors, not just the total binding energy of the system.",
"Is there a reason Be8 is an outlier? After reading your answer I did a little more research and it seems like this i... | [
"The vast majority of nuclides are unstable. A better question would be \"Why ",
" it be?\"."
] |
[
"When you drink water, how is it distributed around the body?"
] | [
false
] | null | [
"Once water is absorbed through the GI tract, it enters the bloodstream as plasma volume and is carried throughout the body. There is no specific distribution (eg the body does not route water specifically to an organ), but the flow is just determined by the circulatory dynamics. From there, water follows a gener... | [
"This guy/girl knows his/her stuff. This is the only answer that needs to be given. The only modification is that, for the most part, outside of cirrhosis, albumin has never been proven to do anything better than saline. "
] | [
"There is no water 'designated to flush out waste products'. Water that you excrete comes gets into the renal system primarily by hydrostatic and osmotic pressures across the glomerular membrane. These pressures are modulated to some extent by feedback pathways involving the renin-aldosterone-angiotensin system. ... |
[
"Why does vision use the wavelengths it does?"
] | [
false
] | Is there some specific reason 400-700nm is easier to detect or better to use for vision? Or is it just what happened to evolve? | [
"Because the sun accurately approximates a black body, it emits light as a function of its temperature producing ",
"this curve here",
".",
"As you can see, the most intense light happens to be what we call the visible region. Most likely photosensitive cells in primitive eyes that detected the most intense w... | [
"Equally important is that 400–700 nm light is largely permitted (as opposed to absorbed or reflected) by Earth’s atmosphere. This is called the ",
"optical window",
".",
"Eyes based on light from the radio window would have to work on different principles than normal eyes, and even then would give poor resol... | [
"Green happens to be a color that our sun puts out little of relative to the other wavelengths",
"No, not only did you not answer the question asked, but your answer as to why plants are green isn't true. The black body spectrum of the sun ",
" at about 500-520nm, in the ",
" part of the visible spectrum. S... |
[
"Why do food and dishes seem to get \"wet\" in the microwave?"
] | [
false
] | Specifically, what causes condensation on dishes and the general "sogginess" of food when heated in a microwave? | [
"Water from within the food gets vaporized because of the heat and accumulates in the airspace of the microwave oven. When the microwave goes off and you forget to open the door (or you open the door soon too) part of the vapor condenses back and settles on wherever it can, hence the moisture. ",
"Since microwave... | [
"Technically, microwaves can excite any polar molecule, but of all the \"typical\" chemicals out there water works the best. But a microwave would, for example, heat pure ethanol."
] | [
"Everclear (190 proof alcohol) wouldn't explode in a microwave?"
] |
[
"If I stand on my lawn holding a mirror facing the sun, will any of the sun’s reflected light reach the surface of the sun?"
] | [
false
] | null | [
"a persons eye will not intercept enough of them to make out the original beam.",
"Assuming:",
"Your flashlight has a beam divergence of 30 degrees.",
"The beam size is focused to 1cm at 10cm away.",
"The flashlight has a 1W yellow light output at exactly 580 nm.",
"The diameter of the flashlight beam at ... | [
"Yes. Once light starts moving in that direction, it will keep going unless, obviously, it's blocked by a satellite, Venus, Mercury or whatever. You could also point a flashlight at the sun, though I don't think anyone standing there would notice it."
] | [
"Yeah, to add to this, I think its important to note that individual photons can make it to the sun, but as soon as the beam exits the flashlight, the large amount of photons start to disperse. So by the time the \"beam\" reaches the sun the photons will be so spread out that a persons eye will not intercept enough... |
[
"How good is the magnification and resolution of the very best satellites in orbit, which are aimed at the planet?"
] | [
false
] | null | [
"I'd heard stories in the 80s of being able to tell what kind of wrist watch you had on, but that's speculation, lets look at what we do know for sure.",
"Hubble's 2.4 meter mirror achieves a resolution of about 0.04 arcseconds. That's equivalent to 58 mm at a distance of 300 km. The spy satellites are roughly th... | [
"it is isnt really a fair comparison because the hubble looking at earth has to look through our atmosphere that scatters and distorts the image. they have correction techniques but it isn't perfect."
] | [
"I'm not sure what fair comparison I made. Hubble has a res of ",
"58mm@330kms",
"... The spy satellites are roughly the same size as Hubble, but they're looking down through a turbulent atmosphere\". The KH-11 has a resolution of 15cm (which is not 5.8cm)."
] |
[
"If a person left Earth and were to travel in a straight line, would the chance of them hitting a star closer to 0% or 100%?"
] | [
false
] | In other words, is the number of stars so large that it's almost a given that it's bound to happen or is the universe that imense that it's improbable? | [
"Assuming you travel fast enough to make gravitational effects irrelevant: You have a ~0.0005% chance to hit the Sun. If you don't hit that your chance to hit a star at any point in the future is well below 0.000000001%, most of that coming from the first ~1000 light years. If you don't hit anything in that region ... | [
"Here's another way to see this. In about 4 billion years, the Milky Way and Andromeda will collide and form a new galaxy. They predict no stars will collide with each other during the event"
] | [
"Since no one has mentioned it, this is almost the same as ",
"Olber’s Paradox",
":",
"in an infinite long-lived universe,\nany direction you look you should eventually see a star,\nand yet most of the night sky is dark.\n",
"There’s a long history behind this question going at least a millennium, but Olber... |
[
"Questions from a creationist"
] | [
false
] | Hello everyone! I am in the midst of a creationism vs. evolution debate with a friend on Facebook, but I cannot answer all of his questions in an appropriate manner, as I am not scientifically minded. So, who better to ask than AskScience! Here is his list of questions, they span many subjects and many fields; from ast... | [
"How did the big bang theory defy the preservation law of angular momentum?",
"Not sure what he is trying to say here. Get your friend to explain this point more.",
"How did the hydrogen from the big bang manage to evolve atomically into all of the elements we find today (considering we can't fuse past lead)?",... | [
"How did the big bang theory defy the preservation law of angular momentum?",
"It didn't. The spin of the universe ",
"appears to be zero",
".",
"How did the hydrogen from the big bang manage to evolve atomically into all of the elements we find today (considering we can't fuse past lead)?",
"Fusion. This... | [
"Turn about is fair play:",
"What elementary particle carries the force of God's will? Ask him to design a experiment that shows God exists. ",
"\"We can't understand the mystery of God\" is the typical dodge there. If it interacts with the universe, we should be able to detect it, if it doesn't, then it can't... |
[
"[Genetics] Does DNA serve more purposes than just being a \"protein cookbook for cells\"?"
] | [
false
] | My knowledge of genetics is from high school and a couple of decades old, so all I know is how DNA via RNA tell the ribosomes how to assemble amino acids into proteins, and the fact that certain genes somehow become activated and deactived. I know this is a huge question, but I would really like to get an idea of where... | [
"There have been strong trends in trying to understand more about both ",
"epigenetics",
" and ",
"non-coding DNA",
". In particular, the latter was until recently referred to as \"junk\" DNA, but now we know that this notion isn't quite true, and that a large portion of non-coding DNA does serve a purpose.... | [
"Oligonucleotides are an interesting research frontier -- they are single stranded DNA or RNA similar in function to peptides but are not composed of amino acids. They can be composed of artificial nucleobases other than GACT (in which case they are termed XNA) which can be engineered to imbue them with useful prop... | [
"There is also another interesting artificial use of DNA as a nanoscale building material. For example, the technique of ",
"DNA Origami",
" can be used to create certain 3D structures consisting of DNA, which might have some useful applications.",
"But in the end, to my knowledge, DNA is \"nothing more\" tha... |
[
"I just calculated that there's 208000 pounds of water in my swimming pool. Why don't I feel immense pressure on the bottom of the pool?"
] | [
false
] | Dumb question, but I was never good at fluid physics, better at mechanics. | [
"Because only the water directly above you is doing any pressure, as weight is a vertical force. Same for air, atmospheric pressure is what the air directly above you does on you, not what the entire atmosphere's mass would do.",
"That said, if your pool was deep enough (ie, if you had enough water directly above... | [
"Just wanted to provide the derivation of what you said, since the OP seems interested in physics stuff:",
"Let's say you have a cube with area 6A (such that each side had area A) meters",
" . If you are at depth X, then the volume of water above you is X*A meters",
" . This volume can be converted to mass ... | [
"It doesn't matter how much total water there is in the pool, just how much is above you. That 'water column' increases in pressure by about 1 atmosphere every 10 meters iirc, so you'd need a really deep pool to actually feel any difference.",
"To extend the example to an extreme, the oceans of the Earth have so... |
[
"Adding salt to water to create a brine solution will lower the freezing temperature of water (the solution). But is there anything you can add to water that will RAISE the freezing temperature?"
] | [
false
] | Other than changing the air pressure? | [
"just to clarify: the long way of saying \"no\"."
] | [
"The ",
"colligative property",
" is known as freezing point ",
". The long and short of it is that any solute will lower the freezing point of the solvent, raise the boiling point, and so on. "
] | [
"From ",
"here."
] |
[
"How is the Bekenstein bound reconciled with the apparent real number nature of the universe?"
] | [
false
] | My understanding was that experiments such as the Lorentz invariance results achieved by Fermilab in 2009 put the minimum "pixel size" for the universe (if the universe is discrete at all) to well below the Planck length. Doesn't this imply that the information needed to store even the position/velocity of a single pho... | [
"Doesn't this imply that the information needed to store even the position/velocity of a single photon would be higher than the Bekenstein bound for a volume enclosing it?",
"I don't follow this line of thought. Why would the position and velocity of a photon have an entropy associated with it? If I were asked ab... | [
"Well, maybe what the bound is suggesting is that the Universe is not discrete at all (what reason would there be for it?) and that ",
" it admits a holographic duality with a 3D theory on the boundary - the holographic principle.",
"This is a very exciting prediction of holography; ",
" the bulk theory (the ... | [
"I think I see where you're going as far as being unable to measure the position of a particle with precision greater than Planck. It seems like you can measure the angle of motion of a particle with arbitrary precision though - just by having a distant boundary and seeing where it hits. Is the implication then tha... |
[
"How do governments increase corporate tax rates without the corporation(s) passing the cost of the rate hikes directly to the consumer?"
] | [
false
] | Let's assume a government wants to increase the tax rates on the insurance industry. Is there a method governments have to increase taxes on corporate earnings, while ensuring insurance rates do not increase as a direct result? | [
"To ensure it? No. Taxes are just costs. The people running a company subject to increased costs can raise prices, cut production costs (cheaper materials, lower wages, etc.), or accept reduced profits.",
"It's up to them how they do it, and I'm unaware of any clear method a government could use to force the i... | [
"Taxing sales, the cost is shared between the producer and consumer. It is not strictly passed on. The amount paid by each party is related to elasticity of demand. ",
"Taxing profits, no cost is passed onto the consumer. However, this does is disincentive for investing, so this could lead to fewer investments in... | [
"Dude, this basically economics 101. Regardless of whether tax is levied on consumers or producers, the burden is distributed upon BOTH consumers and producers. HOW MUCH each side pays depends on the elasticity of demand (basically, the slope of the demand curve):",
"http://en.wikipedia.org/wiki/Price_elasticity_... |
[
"If the speed of light is not relative to its source, what is it relative to?"
] | [
false
] | Is the speed of light absolute? Can the "true" speed of the earth be calculated by observing how fast it moves relative to how fast light moves in the vacuum surrounding it? If so, what point of reference determines "absolute"? what is "still" ? | [
"Is the speed of light absolute? ",
"The speed of light is absolute in the sense that it is the same ",
".",
"Can the \"true\" speed of the earth be calculated by observing how fast it moves relative to how fast light moves in the vacuum surrounding it? If so, what point of reference determines \"absolute\"? ... | [
"In that case, how fast is Earth moving through space relative to the edges of the observable universe?",
"I don't have an answer for you, but I believe using the CMB (cosmic microwave background) as a reference for relative motion is done in modern astrophysics."
] | [
"Correct; see ",
"luminiferous aether",
", which was the belief before Einstein's special theory of relativity."
] |
[
"If my car were about to run out of gas, would I get further by keeping my car at the speed limit or by traveling at the fastest speed possible?"
] | [
false
] | [deleted] | [
"Most cars get there best gas mileage between 35 and 60 miles per hour. ",
"Two factors are primarily responsible.",
"While road resistance varies by road surface, the wind resistance increases with speed increases is disproportionaly larger.",
"See for more technical explanation:\n",
"http://auto.howstuff... | [
"It's complicated.",
"People who strive to maximize fuel efficiency in typical cars will employ a 'pulse and glide' technique. ",
"http://en.wikipedia.org/wiki/Energy-efficient_driving#Pulse_and_Glide",
"If you want to make simplifying assumptions, you'll have to be specific about what they are. In general,... | [
"By \"come to a complete stop\" I assume you mean run out of gas and roll until you stop. You would need to find a balance between how far you can go with gas and without it. As ",
"/u/lamblane",
" said most cars get best gas mileage between 35 and 60, I have seen it said to be around 50, so our numbers match u... |
[
"How close are we to \"solving\" chess with computers?"
] | [
false
] | null | [
"I was under the impression that a \"solved\" game (checkers, tic tac toe, etc) was one where the outcome of the game can be predicted and a computer would never lose if played perfectly. "
] | [
"I was under the impression that a \"solved\" game (checkers, tic tac toe, etc) was one where the outcome of the game can be predicted and a computer would never lose if played perfectly. "
] | [
"Is there a rough estimation of the computing power needed?"
] |
[
"What determines whether a (solid) object is transparent or not?"
] | [
false
] | Follow up question: Does "transparency" exist for other waves apart from light, e.g. Sound? | [
"When light (a photon) encounters an atom, it's energy can either be absorbed, be reflected or pass through the atom. In order to be absorbed or reflected, the energy contained in the photon has to be enough to elevate an atom's electron to a higher energy state, but when this doesn't happen due to the material's e... | [
"the energy contained in the photon has to be enough to elevate an atom's electron to a higher energy state",
"Well the covalent bonds in glass aren't going to interact strongly with (edit:) visible light either, so light can pass through.",
"In both your cases, your explanations cannot explain why ",
"quartz... | [
"Would this also explain why IR light is able to pass through a trash bag but visible light isn't? "
] |
[
"Google didn't come up with anything useful, so here goes - how does a person with a mechanical heart die, assuming that the heart never malfunctions?"
] | [
false
] | Basically what I asked in the title - if a person is fitted with a permanent electronic heart, and the heart never fails, how does the person die? Edit: thanks guys! | [
"Kidney failure, liver failure, brain aneurysm, bullet to the head, lung cancer, blood loss. Your heart is not the only thing that can kill you. The heart could keep beating inside a dead body, wouldn't make a damn bit of difference. Sure they would be \"alive\" in the sense that their heart continues to beat, but... | [
"Diseases of the heart are only ",
"one way to die",
"."
] | [
"I think it's due to infection and dehydration due to fluid loss."
] |
[
"Why does air temperature increase with altitude through the stratosphere?"
] | [
false
] | What I'm really wondering is what the cause for the changes in heating and cooling at different altitudes that occur in the standard atmosphere model. See graph below What is the driving force behind this? I'm also very curious about what casues the tropopause, stratopause and mesopause | [
"The heating in the stratosphere is due to the formation of ozone. O2 is photolyzed by light with a wavelength between .24 and .31 microns, UV light. This produces two oxygen atoms. An oxygen atom then reacts with O2 to form ozone. This last reaction is exothermic, meaning that it releases heat. There is a com... | [
"At sea level the atmosphere is dense and the atmospheric effect (aka [1] the greenhouse effect) is strong. At higher elevations, the atmosphere is much less dense, thus significantly weakening the atmospheric effect and dropping the temperature.",
"That doesn't really explain why you get a similar tropospheric t... | [
"Totally solid explanation here, but a minor terminology quibble...",
"The decrease in temperature with height in the tropopause is due to the fact that the tropopause is heated from the bottom.",
"I think you might have meant \"troposphere\" here, since the tropopause is a single location where troposphere and... |
[
"Do the large genome sizes of organisms like Marbled lungfish, P. Dubium, and P. Japonica provide any sort of evolutionary advantage in and of themselves?"
] | [
false
] | null | [
"I don't think this applies. The rate of mutation is not per genome, but per nucleotide. So the overall mutation rate of the genome is simply 10X bigger if there are 10X nucleotides to mutate.",
"In general, organisms with shorter life cycle (and thus most opportunity for evolution) have smaller genomes. So yea, ... | [
"seed size (in plants)",
"This one is totally bizarre. One of the refs in the paper you cited said that genome size is highly correlated with both seed and leaf (!) size in soybeans. The leaf thing is just weird.",
"http://link.springer.com/article/10.1007%2Fs001220050840#page-2"
] | [
"seed size (in plants)",
"This one is totally bizarre. One of the refs in the paper you cited said that genome size is highly correlated with both seed and leaf (!) size in soybeans. The leaf thing is just weird.",
"http://link.springer.com/article/10.1007%2Fs001220050840#page-2"
] |
[
"How and why do animals have retractable claws?"
] | [
false
] | That's probably a vaguer question than I intend but I can't think of a better way to put it. I guess what I'm asking for is like a basic overview of the function of claws, on an evolutionary basis or whatever's easiest to explain. Like, why does my cat not just have claws, but claws that can be controlled in the way th... | [
"How: They just flip the toe tip upward, folding the claw to the top of the toe and into a fold in the skin of the paw. Good image here: ",
"http://www.pictures-of-kittens-and-cats.com/feline-anatomy-bones-and-joints#",
" ",
"Why: If claws are sticking out all the time, they are constantly rubbing again... | [
"I took my undergrad in ecology and evolutionary biology, and basically did a bunch of ecology related biology courses--everything I could get that looked interesting. Then I got a masters in marine biology at the Three Seas Program, and am currently working on a PhD studying sexual selection and the behavior of s... | [
"A claw is made of hard protein called keratin. Claws are used to catch and hold prey in carnivorous mammals such as cats and dogs, but may also be used for such purposes as digging, climbing trees, self-defense etc., in those and other species.",
"Here's a diagram of the internal anatomy of a cat's paw, showing ... |
[
"Is there any psychological explanation about \"the seven-year itch\"?"
] | [
false
] | Most of you might have had the experience, in my surroundings there were two couples in the last week, that broke up because of the seven-year itch. I don't know if it is statistically proven that a lot of patnerships break up after about 7 years or shortly before, but from my personal experience I can say it definetly... | [
"This all sounds like laymen anecdotal information and layman speculation to me."
] | [
"The evolutionary psychology explanation is that this is the standard length of time required to mate and raise offspring to a point that they don't require constant attention. The presumption is that males that left their mates earlier had a disproportionate number of their offspring dying due to lack of parental ... | [
"50% of marriages fail",
"This statistic, which has been passed around to the point where it is generally considered \"common knowledge,\" is not, and never has been true."
] |
[
"If the earth rotated fast enough, could centrifugal force overcome gravity?"
] | [
false
] | Similarly, are we less affected by gravity right now, because there is SOME centrifugal force opposing gravity? | [
"Yes, it is possible, a day would have to be about an hour and half (which is the time it takes an object in orbit to go around once) for gravity to equal centrifugal force at the equator. "
] | [
": while the Earth likely never was at a point where the centrifugal force overcame gravity, this ",
" happen on asteroids. Unlike the Earth, asteroids can be spun up by radiative effects (e.g. ",
"YORP",
" ).",
"There's evidence that asteroids actually shed mass due to this process. The ",
"distributio... | [
"That isn't really true. In a rotating reference frame, there are terms that clearly correspond to both the centrifugal force and the coriolis force. You could argue that these forces are fictitious, as they only appear in a non-inertial frame of reference, but then you'd need to include gravity as well. Indeed, th... |
[
"How does stickyness work?"
] | [
false
] | null | [
"It depends on the kind of sticky since there are several phenomenons that can cause stickiness.",
"The two biggest reasons something is sticky is either because it tends to make intermolecular bonds (such as hydrogen bonding) or because it consists of long molecules that tangle up like velcro."
] | [
"Yes. Glues like Epoxy and cyanoacrylate polymerize as they cure forming long polymer chains (generally a one way reaction). Sugar just forms H bonds. That's why you can pull apart things stuck with sugar and they'll re-stick (as long as it is still moist and not dirty) but you can't do that with glue"
] | [
"Is that what the difference between an industrial epoxy glue, and, say, a sugary drink spilled on the floor is?"
] |
[
"How thick would a steel sphere around an Atomic Bomb (non-hydrogen WWII) be in order to sustain the blast?"
] | [
false
] | null | [
"This does not quite answer your question, but it is related: ",
"wikipedia",
" states that in order for an underground nuclear explosion to be contained, the depth of the burial in meters must be greater than approximately one hundred times the cube root of the yield in kilotons. If we make the wild leap of ... | [
"As an order of magnitude estimate..",
"The bulk modulus of steel is about 100 GPa (142 GPa according to ",
"alpha",
"). This tells us the fractional change in the volume of steel when subjected to a certain pressure.",
"We can also use it to estimate how much energy it would take to completely vaporize a ... | [
"I can set an approximate lower limit:",
"WWII bomb is ~15 kilotons of TNT, which is about 6x10",
" J.",
"The latent heat of fusion of steel can be ~270 kJ/kg, and heat capacity is ~0.5 kJ/kgK and melting point around 1400 C, so the total energy need to melt steel from room temperature is right around 1x10",
... |
[
"How does knowing the earths diameter help us?"
] | [
false
] | null | [
"Thank you very much for the direction!"
] | [
"Greetings ",
"/u/Sharplynormal",
"Your question, while interesting, falls outside the purview of ",
"/r/askscience",
" which deals with closed questions requiring indepth analysis from peer reviewed sources.",
"You are encouraged, however, to bring your question to our sister/sub: ",
"/r/asksciencedisc... | [
"A pleasure - ",
"/r/askscience",
" discussion really deserves more visibility."
] |
[
"Pfizer vaccine was initially recommended to be stored at -60C to -80C for transportation. Is the vaccine still at a liquid state at this temperature or is it frozen solid?"
] | [
false
] | null | [
"It can now be stored at 2-8 degrees C for up to 30 days after defrosting and before dilution. Yes it’s solidly frozen when it arrives but thaws very quickly. The vial contains 0.45ml of undiluted vaccine which once thawed is diluted with 1.8ml of Saline to bring it to 2.25ml total volume. This is how we can always... | [
"It means it can be thawed in very small amounts so that if you have to thaw one more at the end of the day to cover the last few walk ins you waste 3-4 doses instead of 20. It also means if any one vial is broken or compromised in any way that it limits the impact to a few doses at a time. It reduces the risk of l... | [
"A question I never knew I needed answered. Why are the actual vials so tiny? Why not make them bigger?"
] |
[
"How is vocal pitch determined?"
] | [
false
] | Is it genetic, environmental, a combination of the two? | [
"Yay I can answer this!",
"Pitch is determined by the properties of your vocal folds. 3 things determine a person's pitch: length, mass, and stiffness. Greater mass equals lower pitch. Longer vocal folds AT REST equal lower pitch. LENGTHENED vocal folds (achieved by moving your thyroid cartilage, which houses the... | [
"It's also cultural to some degree. I'm trilingual and my mean pitch (F0) is different in all three. And it's completely unconscious on my part... I've just adapted to each language."
] | [
"Behaviorally, yeah you can absolutely change your fundamental frequency. Not positive I'd call it cultural, though...I'd be so interested in a study comparing Fo of different cultures."
] |
[
"According to my sons dinosaur books there are \"bird hipped\" and \"lizard hipped\" dinosaurs. However, theropods are thought to have evolved into birds, yet theropods are \"lizard hipped\". Why is this?"
] | [
false
] | null | [
"It refers to their hip structure; a \"bird hip\" looks like ",
"this",
", and a \"lizard hip\" looks like ",
"this",
".",
"It turns out that theropods, ",
" have the lizard-like hip structure. The bird-like hip structure evolved separately in the bird hipped dinosaurs and in the theropods' descendants;... | [
"Yeah, nature is ridiculous sometimes. Come on, am I really supposed to believe that ",
"this guy",
" was a dangerous predator?"
] | [
"That's amazing. ",
"So 65 million years ago therapods had lizard hips, and since then their hips have evolved into the bird hips we see today, which are similar to the bird-hipped dinosaurs?",
"Nature is crazy."
] |
[
"Temperature - Emergent?"
] | [
false
] | Temperature is an emergent property, apparantly. But if you were to remove a molecule of water from a hot coffee it would continue to radiate IR until it reached equilibrium with its environment. Surely that IR intensity could be measured and a temperature calculated, or have I missed something. By a similar reasoning ... | [
"Yes, temperature is an emergent quantity which is only defined is a system of many particles and we do not track the individual motion of the particles. The same can be said about pressure in the context of statistical mechanics (with some caveats) - we're not literally calculating the force of each particle and d... | [
"time is an emergent property of the universe because it seemed to have no significance at the quantum level.",
"They were probably talking about the arrow of time (direction of time), as time seems to always 'move forward' in the universe, while the Schrodinger equation etc. are time-reversal invariant. "
] | [
"time is an emergent property of the universe because it seemed to have no significance at the quantum level.",
"They were probably talking about the arrow of time (direction of time), as time seems to always 'move forward' in the universe, while the Schrodinger equation etc. are time-reversal invariant. "
] |
[
"Where do phosphodiester bonds occur?"
] | [
false
] | I know that they’re only occurring in nucleic acids, but do they occur anywhere else, like proteins/amino acids? And where in DNA does it occur? As in, are they inter-nucleotide bonds or intra-nucleotide bonds? And what’s the difference between an oligonucleotide and a polynucleotide? | [
"Lots of questions here:"
] | [
"Poorly written question. There is no strictly, literally, correct option, since any molecule with -OH group(s) can potentially become be given a phosphopiester {..-O-P-O-..} group, as ",
"/u/alphaMHC",
" referred to. This includes proteins, and of course histones contain both protein and DNA. So the pedantic a... | [
"Phosphodiester bonds are what links one base to the next in DNA and RNA (though the backbone). A quick look at the chemical structure of DNA should make it clear how they are linked up.",
"https://en.wikipedia.org/wiki/Phosphodiester_bond",
"They are not found in proteins or amino acids. ",
"Oligo = \"few\",... |
[
"Would it be theoretically possible to reduce your chance of heart attack or stroke to 0 by changing your diet?"
] | [
false
] | null | [
"Having a heart puts you at risk for a heart attack. There are many more factors (many that we still do not know or understand) that can result in or contribute to heart attack or stroke than diet. Aging of cells and genetic predispositions are unpreventable and attribute significantly to risk. I personally feel... | [
"Given that the body also produces it's own cholesterol (as it is required by certain body processes) it would be impossible to completely remove cholesterol from the body entirely. ",
"In any case, many things put you at risk of heart attack (myocardial infarction) and stroke, such as high blood pressure, high s... | [
"Cholesterol is an essential part of the human body. People hear that having high cholesterol is a risk factor for stroke and MI, however few realise that it is an absolute neccessity in the production of the cells which make up our body, bile acids, and some vitamins. The problem with cholesterol however is that i... |
[
"How (in)accurate is this article?"
] | [
false
] | null | [
"It's totally inaccurate. Don't really need to say much more. Do a search of AskScience about vaccines and you should come up with discussions on this topic."
] | [
"I figured it was, but I'm looking for specific points to bring up about this particular study. I assumed the flaws would appear in the statistics and the study structure itself."
] | [
"Do a search. We've had huge threads on this kind of stuff in the past. "
] |
[
"What will double the energy do for the Large Hadron Collider?"
] | [
false
] | With the LHC due to come back online with almost double the energy being used in collisions, what are they hoping to achieve if the particles are already moving at near light speed? Does this allow for more or bigger particles or groups? Maybe it will allow for longer reactions? My ignorance makes for annoying curiosit... | [
"what are they hoping to achieve if the particles are already moving at near light speed?",
"Just to clarify, the actual speed of the particles is mostly irrelevant at this stage. Everything is basically going at the speed of light already, what's interesting is their energy. A particle's speed is capped at the s... | [
"We are giving them kinetic energy. The usual formula E_k = 1/2mv",
" is just an approximation that's only valid a low energies. As a particle reaches relativistic speeds its kinetic energy starts rapidly increasing without limit as you approach the speed of light."
] | [
"Relativistic mass is an outdated concept. These days (at least in particle physics) we just call it energy."
] |
[
"How do I do quantum levitation at home"
] | [
false
] | [deleted] | [
"A high temperature superconductor (like Yttrium Barrium Copper Oxide), liquid nitrogen, and a magnet."
] | [
"I'm really not sure where you are getting your numbers. Rare earth magnets, maybe 10 bucks for a dozen. Liquid Nitrogen? Cheaper than water. Super ceramic super conductors? Not sure how expensive but cheap enough in college they let us each take home a piece. "
] | [
"I'm really not sure where you are getting your numbers. Rare earth magnets, maybe 10 bucks for a dozen. Liquid Nitrogen? Cheaper than water. Super ceramic super conductors? Not sure how expensive but cheap enough in college they let us each take home a piece. "
] |
[
"If an organism could live for hundreds of millions of years could it evolve drastically?"
] | [
false
] | [deleted] | [
"You are using the word \"evolve\", but I think you mean \"mutate\". The organism would accumulate mutations, which could lead to an accelerated mutation rate (think of the way a cell receives a carcinogenic mutation, then becomes more at risk for other mutations as a result). It is more likely that rather than mut... | [
"The process of evolution would not act on the individual being. The likelihood of passing its genes on, if it remained in a sexually mature state for a long period of time, however, would increase the presence of its genes in the next generations, meaning, from an evolutionary standpoint, that it was more fit to p... | [
"The Theory Of Evolution is specifically about changes between ",
" and a parent. The length of time something lives for is not the factor which affects the rate at which something evolves. Rather, it is the rate at which it reproduces which produces change more quickly. Bacteria is mutating all the time because ... |
[
"Is it possible for a mass to be composed entirely of protons or neutrons?"
] | [
false
] | [deleted] | [
"Hydrogen, if you remove deuterium and tritium from it, is composed entirely of protons and electrons."
] | [
"There are no bound nuclei with A > 1 and either Z = 0 or N = 0. There are things like neutron stars, but they’re not composed of ",
" neutrons."
] | [
"Edit: I meant to say electrons, not neutrons."
] |
[
"What is the most accurate way to visualize an atom?"
] | [
false
] | null | [
"When I got into quantum physics, and realized the electron exists in every location and in every direction all at the same time without technically existing, I now picture an atom as one big scribble mark on a page. "
] | [
"A nucleus made up of subatomic particles and an outer volume of space occupied by electrons.",
"The question is, can the electron be thought of as a negatively charged particle orbiting a positive nucleus, like a planetary orbital? To make early chemistry/physics class easy, yes. But it's actually a continuous... | [
"Welcome to ",
"r/askscience",
". Memes are not tolerated here. For more, please read our ",
"guidelines",
"."
] |
[
"Where exactly does blood meet cells and how is it used?"
] | [
false
] | At what point does lymph appear in all this? How is lymph fluid differentiated from blood? | [
"Your blood vessels start out thick (arteries) and then divide into smaller and smaller tubes (arterioles) until the vessels are incredibly small (capillaries). Every cell in your body is within two cell widths from a capillary. Blood flowing through these capillaries transfer chemicals into the cell via either pas... | [
"Every cell in your body is within two cell widths from a capillary",
"Though the rest of your post is good, I must point out that this is false. Cells of the cornea, which is avascular, are much farther away.",
"Here's wikipedia",
"Since the cornea is avascular, which renders it optimally transparent, the nu... | [
"interestingly (and dbssig you probably already know this), the avascularity (lack of blood vessels) in the cornea is what allowed a clever guy to prove that cancers create their own blood vessels. he put some cancer cells on the cornea of a rabbit (dick move, i know) and the cells didn't grow immediately into a ma... |
[
"How is behaviour innate? How can animals replicate behaviour that they have never observed?"
] | [
false
] | So, I know that some behaviour in animals is innate, I also understand why, but I don't understand how (except reflexes). Like, how do animals know mating rituals, or what to do when they see another animal, or how to hunt, or howl, etc.. And I know that there are instincts, but where do they come from? As in, what par... | [
"Those types of behaviors are similar to reflexes, they are “hard wired” and are initiated by an environmental cue. Often it is a series of behaviors that are initiated...an environmental cue initiated one behavior, and that behavior initiates a second behavior, and so on. Essentially, they are behavior patterns th... | [
"Yes, it's genetically encoded. I would suggest you take a look at this article: ",
"https://en.wikipedia.org/wiki/Fixed_action_pattern",
" and also the sources which it cites"
] | [
"Also hormones play a key role too. Imagine, when our body is ready to mate, we release lots of hormones that in a way tricks up into mating and makes our brain see, think and feel in a certain way. This is also the only way to actually reproduce too, so our body knows that's what it needs to do. I guess when we we... |
[
"Is there any science behind black people being more athletically talented naturally? If so, what are the reasons?"
] | [
false
] | null | [
"Depends how you define athleticism. The strength events like weightlifting are all dominated by white and Asian people. ",
"Anyway, there are a few reasons for this. One is that [black people have generally shorter torsos and longer legs, making them more suited to running. Black people also have a higher propor... | [
"Extremely touchy subject.",
"It depends what study you look at, and what you mean, and what you define as black people.",
"An excellent article on this is located below.",
"http://ajcn.nutrition.org/content/71/6/1392.long",
"This is general differences, mainly they are small and a lot of factors are very h... | [
"west africans specifically have a higher percentage of % fast twitch fibers. "
] |
[
"Why don't we use fractions of a revolution to express angles?"
] | [
false
] | In mathematics, we use radians, but taylor series aside, they are almost always expressed as a multiple of pi (2pi radians, pi/4 radians etc.) It seems to me that it would be simpler, more intuitive and just as dimensionless to just use fractions of a full revolution. | [
"The concept does exist, it's call a ",
"turn",
". The main advantage of radians is that trigonometric functions are most naturally expressed as functions of radians. I don't know the history of how things came to be though.",
"Also note that when talking about frequency it is common to talk about multiples o... | [
"Derivation and integration of trigonometric functions is simpler using radians. For example:",
" d/dx sin(x) = cos(x)\n",
"when you use radians, but becomes:",
" d/dx sin(x) = (pi/180) cos(x)\n",
"when angles are measured in degrees. They are also useful for converting units in angular and linear dynamic... | [
"The ",
"sine function",
" start at zero, and reaches 1 by pi/2 (around 1.57) radians. If you are working in turns, the sine function goes from 0 to 1 in only 0.25 turns.",
"Since the derivative describes the slope, and slope is rise/run, it is about 6 times (actually 2pi) steeper if you use turns rather than... |
[
"Are there any other animal species showing signs of advanced intelligence like humans?"
] | [
false
] | I don't know exactly how to word it, and I don't want to mislead someone to answer thoroughly but be off the meaning of my question. I know evolution takes a long time compared to a human's perspective, but have species been recorded to show particular evolutionary progress similar to humans? I understand certain ape s... | [
"Not only break trash into smaller pieces for more food, but then baiting seagulls with the food and catching the gulls for even larger rewards.",
"That's planning and having a concept of long-term reward at a cost of forfeiting small short term rewards.",
"Which makes the dolphin financially wiser than most yo... | [
"Dolphins, certain apes, elephants, crows (and similar birds), pigs, pigeons, squirrels, and rats are all considered highly intelligent creatures. But they don't tend to plan ahead in the way that humans do, which has been a big stipulation in determining human level intelligence.",
"There has been one chimp that... | [
"I have to disagree with this perspective. There's been a lot of work in Corvids (scrub jays) about planning ahead. Scrub jays make food caches for winter, and have been shown to:",
"Know the rate at which different foods go bad, use foods in the order in which they go bad and refrain from searching for food wh... |
[
"Why don't raindrops reach the speed of termimal velocity when they fall?"
] | [
false
] | null | [
"They do"
] | [
"Every object has a different terminal velocity"
] | [
"I looked up how fast they fall and it said around 20 MPH. I thought the speed of terminal velocity was 120 MPH?"
] |
[
"How does the explosion from inside an engine get harnessed, by say, a car motor?"
] | [
false
] | I've been studying up on engines and how they work. I understand everything up until the explosion produced by the spark plug, in the case of a 2 or 4-stroke engine. After that it gets confusing. How does the explosion inside the chamber get harnessed by the engine to turn the wheels of the car? Is it just pressure in ... | [
"The piston prevents the pressure from escaping and there's a small rotary device that also has a revolution mechanism that continues the momentum so the the force from the explosion pushes the piston up then the revolution continues and pulls the piston downward."
] | [
"Technically, it is ",
"deflagration",
" (controlled burning), not ",
"explosion",
" and not ",
"detonation",
".",
"Burning causes the gas inside the cylinder to heat up, heating up increases the pressure in the cylinder, and the pressure pushes the piston down, all happening in a fraction of a second... | [
"Detonation is specifically avoided in internal combustion engines. Anti-knock additives are mixed into gasoline to moderate the combustion reaction."
] |
[
"Has toothpaste improved over the years?"
] | [
false
] | null | [
"Most toothpastes have one common and most important active ingredient: Sodium Fluoride which interacts with Hydroxyapatite of tooth enamel, making it regenerate faster, becoming stronger and less susceptible to the acid in your mouth. The percentage of Sodium Fluoride in toothpastes stays the same over the years, ... | [
"Greeks and Romans used crushed bone and oyster shells as abrasives in toothpaste",
"Tooth powders were very popular in 1800's-WW1. Originally were made of chalk, crushed brick, or salt. Arm & Hammer sold baking soda tooth powder.",
"Pre mixed toothpaste sold in collapsable tubes came round turn of the century.... | [
"Thanks for the analysis. Although when someone asks me my source on this knowledge I'll have to say ",
"/u/ThatInternetGuy",
" "
] |
[
"What effect does rock climbing have on long-term hand and finger health?"
] | [
false
] | looks very good but I don't have the vocabulary or journal-reading skill to interpret it well. | [
"If I'm reading it correctly, it appears to state that climbing does not increase your chances of arthritis. It also states that climbing causes the bones in the fingers to be wider than non climbers, hypothetically proposed as additional bone deposits due to the rock climbing; not causing any negative side effects... | [
"Osteoarthritis is a disease of \"wear and tear\" of joints. In can result from uneven joint loading or abnormal joint loading over long periods of time - decades actually. It is not known whether some \"normal\" sporting activities can result in osteoarthritis.",
"Osteoarthritis is not to be confused with arthri... | [
"Not a scientist but a rock climber. The most common finger injury for climbers is an A2 pulley tear that can occur in three classes; class one being a minor sprain, class two being a more serious sprain, and class three being a full tear of the A2 pulley tendon. These injuries can take a long time to recover fro... |
[
"Is the caffeine content of cold-brewed coffee different from that of hot-brewed?"
] | [
false
] | Cold-brewing, for those unfamiliar, generally involves finely grinding coffee beans, then steeping them in room temperature/cold water for 12-24 hours to produce a coffee concentrate that is diluted based on personal taste. Again, speaking generally, the dilution rate about 1:1. Hot brewing typically uses a coarser gr... | [
"Yes, but the time factor is not considered in this, nor is the greater surface area associated with the difference in grinds..."
] | [
"While 2g/100ml is much less than 66g/100ml, it is still far greater than even the strongest cup of coffee. The point is, caffeine is so readily soluble in water it is very quickly and easily extracted from coffee. ",
"Source: \"Caffeine is extracted early, so higher yields do not yield more caffeinated coffee, o... | [
"From Merk",
"Caffeine is moderately soluble in water at room temperature (2 g/100 mL), but very soluble in boiling water (66 g/100 mL)."
] |
[
"What would happen if we were to point the Hubble Space telescope at the Earth?"
] | [
false
] | Barring the fact that the telescope can't be pointed at such a bright object, but this is just a hypothetical question. Would the telescope act as a big optical microscope, or would it have some weird blurry image? | [
"From ",
"HubbleSite.org",
"The surface of the Earth is whizzing by as Hubble orbits, and the pointing system, designed to track the distant stars, cannot track an object on the Earth. The shortest exposure time on any of the Hubble instruments is 0.1 seconds, and in this time Hubble moves about 700 meters, or ... | [
"No.",
"The ",
"rayleigh limit",
" of a 2.4m diameter mirror (which the HST is) looking at 500nm light (blue-green) is ",
"2.5e-7 radians.",
" At an altitutde of 559km (which the HST is) the HST is limited to a resolution of about ",
"14cm.",
"Note that the ",
"KH-11",
" is believed by some",
" ... | [
"I punched the math into WolframAlpha with a few assumptions. First, that the telescope was moved out to geostationary orbit so that it could take steady pictures and second that the Wide Field Camera 3 was used, which has .04 arcsecond pixels. Each pixel of a image of Earth would be about ",
"7 meters across.",
... |
[
"Can't the Hubble Space Telescope take accurate and detailed images of the moon's surface?"
] | [
false
] | [deleted] | [
"I'm going to guess that the focal length on the HST is set way too far out to image the moon. "
] | [
"Did you try googling? ",
"It does indeed."
] | [
"It's not taken by the hubble, but here is a 24000x24000 picture of the moon that you can view."
] |
[
"How is it that some mental disorders appear at a certain age? How can someone be fine one day and then have OCD the next?"
] | [
false
] | "One day" as a figure of speech, of course. Edit- I know triggers exist for these things, but what exactly is a trigger and how does it force an illness to start displaying? | [
"For many disorders, they have age of onset tied to brain development and maturation. For example, schizophrenia, characterized by disorganized thought, has an age of onset in the 20s. This matches with the mylination of the frontal lobe. ",
"Similarly, Alzheimer's is thought to be a maladaptive brain process, wh... | [
"As far as I know, there are two ways of answering your question.",
"1) Diathesis model.\n2) Biopsychosocial model.",
"According to the Diathesis-Stress model, a person is born with the genetic predisposition of a mental disorder. The Stress part is like the \"trigger\" for it. ",
"Lets say a person is born p... | [
"OCD is considered a chronic illness- that is to say that with medication and/or therapeutic coping techniques a person can live symptom-free, but the cessation of meds/behavior modification will result in the return of symptoms.",
"\nNot everyone has success in alleviating their symptoms, and for many the obsess... |
[
"How do brain tumours form?"
] | [
false
] | It's my (most likely flawed) understanding that neurons do not divide. If that is the case how do brain tumours come about? | [
"There are tissue cells in the brains aside form neurons. Those tissues cells form tumors in a similar way to how other cancerous cells work. Basically, the cells mutate so they no longer have an anchorage dependency. An anchorage dependency is basically a cell marker that tells a cell to quit reproducing once it i... | [
"There are other brain cells that multiply more often: astrocytes, Schwann cells, etc. The brain cancers are named after whichever of these other cells multiply out of control.",
"Also, skin cancers “love” to stick the the blood-brain barrier and multiply, so you end up with cancerous skin cells in your brain. Ju... | [
"That makes a lot of sense, thank you."
] |
[
"Is It true that apple seeds are bad for dogs?"
] | [
false
] | [deleted] | [
"Apple seeds contain low levels of cyanide, you'd need to eat a substantial amount of them for it to do you any harm though. It shouldn't hurt him unless there's another reason why they might be bad for him besides that. "
] | [
"Yes, you'd have to finely chew the seeds from dozens of apples before it would have any noticeable effect."
] | [
"Somebody watched the old GI Joe cartoon after school..."
] |
[
"Which way does the scale tip?"
] | [
false
] | On the left is a steel ball suspended from the ceiling in the water, and on the right is a hollow ball tied to the scale also in a cup of water. The balls are equal volume. The density of the hollow ball is the same as air, the steel ball is totally supported by the wire. Since both sides of the scale are of equal mass... | [
"On the right: Since the hollow ball is attached to the floor, the \"action-reaction\" forces can be treated as internal forces and ignored. For acceleration to occur on a system, one needs to consider only the net (external) forces. You can ignore the force on the ball (and balance plate) just like you can ignor... | [
"To simplify: realise that the right hand side is equivalent to the cup of water with no hollow ball in it.",
"Now the question is whether the suspended ball on the left imparts any force on the scale. Now either buoyancy is intuitive to you or, like me, you prefer to see it for yourself.",
"Cup of water",
"\... | [
"Yes, you are right about getting the correct answer. The explanation is not simply weird, it is wrong. One way to think about it is the following: since the explanation supposedly relies only on buoyant effects on the hollow sphere, we can imagine a different experiment with no steel ball on the left. Then, the ... |
[
"Gravity and time dilation?"
] | [
false
] | The closer you are to a massive body in space, the slower times goes to you relative to someone further away. What if you where an equal distance in between two massive bodies of equal size so the gravity cancels out. would time still travel slower for you relative to someone further away? | [
"Yes, a faraway observer would still see your clocks to be running more slowly. I think your misconception is based on the fact the ",
" exactly cancels, so you don't gravitate toward either mass. (Of course, with the standard assumptions, like non-rotating spherical masses.) But time dilation effects don't \"ca... | [
"The rubber sheet analogy is terrible for all sorts of reasons, and I would rather not give any explanation or intuition based on it. The idea of that analogy is that the sheet represents the gravitational potential... if space were two-dimensional ",
" if we were only using a weak-field metric to describe spacet... | [
"Well, how should we even interpret your statement?",
"the more locally curved space is the slower time goes relative to less curved space",
"Seems simple enough. But what do you mean by \"more locally curved\"? Curvature in general is described by something called the ",
", which is a rank-4 tensor. The rank... |
[
"So when i roll around in the grass, why do i get itchy?"
] | [
false
] | I'm not a hippy, but i took a lawn nap and was wondering if i can do anything to prevent it. | [
"You may have a skin allergy to grass."
] | [
"Chiggers"
] | [
"I get itchy from grass, but no mites have ever sprung forth from my skin. But I have been tested, and have no allergies to grass. Hmm."
] |
[
"When we look out at space and observe spatial phenomenon, we can only do so from one angle. Surely this makes analysis difficult. How can astronomers and scientists compensate for this?"
] | [
false
] | null | [
"What is meant by spatial phenomenon? Space the measurement or space as in outer space? ",
"We can find the distances of objects using ",
"parallax",
", which is essentially the use of two angles of reference. If you give the Earth 6 months to revolve around the sun, you can see the same object from 186,00... | [
"Parallax is only useful to a kiloparsec (3260 ly), or so. NASA had proposed the Space Interferometry Mission (",
"SIM",
") to reach about 25 kpc, but it was not recommended. Work on it was discontinued in 2010."
] | [
"Large astronomical distances are very difficult to measure accurately and reliably. Cosmological distance measurements rely on the ",
"cosmic distance ladder",
", a sequence of overlapping methods.",
"There was a long-running controversy (mostly, but not entirely, resolved) about the value of the Hubble par... |
[
"My friend is convinced that microwave ovens destroy nutrients in food. Can askscience help me refute or confirm this?"
] | [
false
] | My friend is convinced that microwave radiation destroys the nutrients in food or somehow breaks them apart into carcinogens. As an engineering physics student I have a pretty good understanding of how microwaves work and was initially skeptical, but also recognize that there could definitely be truth to it. A quick go... | [
"Microwaves don't \"heat water molecules\" as their primary heating action. They create dielectric currents in whatever is being heated, including water. In fact, while sugars and fats have smaller dipole moments and thus absorb less energy, they also have much lower specific heats, so they will heat more quickly... | [
"Becuase a leaky microwave door would put you in direct contact with Microwaves. The same force that heats water molecules in your poptart could heat the ones in your skin. The real question is how long would you have to be exposed to a leak, and how big would the leak have to be, to cause injury? "
] | [
"\"Of the two main types of radiation, ionizing and non-ionizing, only ionizing damages DNA. Microwaves use non-ionizing radiation, meaning it does not have the power to destroy DNA, contrary to many claims otherwise.\"",
"Then why would a leaking microwave be a concern? "
] |
[
"Why is it we can drop an insect of some kind and it will just get up and walk away?"
] | [
false
] | [deleted] | [
"Simple. They have so little mass relative to the air resistance, so they fall slowly, which only makes a small impact. Insects also have a hard exoskeleton, which protects them like a tank."
] | [
"Like TrashCap said they hit the ground with so little ",
" that very little damage is done. Even though everything falls at the same rate of acceleration (near the surface of the earth) the force they hit the ground with is a function of the Acceleration x the Mass of the falling object, or as you may know it F... | [
"TLDR;",
"the bigger they are, the harder they fall."
] |
[
"In a complete vacuum, and with no other external forces present, could a small piece of metal fall in the orbit of an electromagnet?"
] | [
false
] | null | [
"An orbit of that type would be too sensitive to perturbation. Even if it were \"stable\" and we ignore all outside influences as per OP's question, the movement of the metal through the field would cause perturbations by virtue of the fact that charges accelerated by a magnetic field emit radiation. This would imm... | [
"I understand how polarization can destabilize an orbit, but it would not prohibit one. A stable orbit could be quite likely if the metal piece is sufficiently small. Even if it isn't, a stable orbit could be manufactured carefully. ",
"One must prepare a situation in which the metal experiences a 1/r",
" fo... | [
"Yes, though there are more than a few scenarios that come to mind when I think of your question. First let me say, to avoid the pitfall pointed out by Droiganzf, the electromagnet, for example, could be much larger in size than the metal piece.",
"If the \"electromagnet\" you speak of is a sphere which produces... |
[
"Why does hair change colors? Why does facial hair follow suite at a faster rate."
] | [
false
] | So I was born with red hair. By 1st grade it had changed to a blond so pale it glowed in light. After that it's been darkening ever since. Starting in September I was finally able to start growing a beard. It's been growing a deep red but I noticed today that now it's almost 2inches thick......its turning blond..... it... | [
"Your hair color is largely determined by your genes coding for your Melanocytes - the cells in your body that produce melanin, which is a chemical compound that determines the color of your hair and skin. ",
"Melanocytes are found in a lot of places in your body - for the sake of the question I'll discuss the on... | [
"My hair was different shades of red for my entire life - almost blond as a child, gradually becoming darker as I aged. I developed breast cancer - after the chemo, my hair grew in a dark ugly brown. But no gray. I am now over 70 and have a few gray hairs at the temple. My paternal grandparents' hair (both gend... | [
"And while my cell gets these notes, they never show in my inbox!?"
] |
[
"Does a nearby person have more gravitational effect on me than the nearest star?"
] | [
false
] | This is probably completely wrong, but can someone steer me in the right direction? (this isn't an exam question, just curious:)) Gravitational force is given by F = G x m1 x m2 / r A girl is standing 2m away from me. This seems to indicate the nearby girl is attracting me more than the closest star. I hope I'm right, ... | [
"You are correct, but it's even more extreme when you consider the tidal effects, which decay as 1/r",
" instead of 1/r",
"Proxima Centauri though is sometimes considered part of a triple star system with Alpha Centauri, with twice the total mass of the sun."
] | [
"I was curious so I made the distance between the two people a variable and set the two gravitational force equations equal in order to find out how far away the person would need to be in order to exert the same amount of force as Proxima Centauri. I got approximately 577 meters or 1.9 times the height of the Eiff... | [
"These equations have even more potential for a romantic line:",
"We have your mass (77 kg), the mass of the stars of the Milky Way closer to the galactic core than the Sun (very roughly 75% of the ",
"Milky Way's Mass in the form of stars",
", or about 0.75 * 9 * 10",
" solar masses. We only consider the s... |
[
"Long shot. But anyone happen to know a lot about ferrocene based chemotherapy? Or ferrocene in general would be good."
] | [
false
] | I hate Lit Reviews. | [
"what do you want to know about ferrocene? I didnt know that it was used for chemotherapy."
] | [
"Really? What do you know it to be used as/for? Yeah, i've found loads of papers, and it's actually what i'm working on now. From what i've seen, it's applications are massive, aerospace, anti malarial, anti bacterial, other materials.",
"Just have a lit review (god I realy hate lit reviews), on it. Primarily as ... | [
"I usually see it used in electrochemical experiments for a standard, or used as a building block in syntheses, usually for it's redox properties, or as chelating ligands for Pd catalyzed cross coupling. Mostly I see it used as an example of a sandwich complex in inorganic chemistry classes, or an example compound... |
[
"Why exactly do we feel fatigued from \"oversleeping?\""
] | [
false
] | I've recently found I am more tired if I sleep for nine hours than I am if I sleep for six. I am assuming a buildup of hormones produced during sleep are the cause, but would like to know specifics. | [
"If you're not sure, please refrain from attempting to answer.",
"Please keep discussion: \nFree of layman speculation"
] | [
"If you're not sure, please refrain from attempting to answer.",
"Please keep discussion: \nFree of layman speculation"
] | [
"Could I possibly know a source for further reading on this topic? If you drink more before bed,.would you wake up less groggy?"
] |
[
"What would a substance that is one atom thick look and act like?"
] | [
false
] | [deleted] | [
"In ",
"this",
" image, the dark square in the middle is a one-atom thick layer of carbon."
] | [
"It's really remarkable to me that graphene absorbs enough light to be visible to the naked eye or under an optical microscope, despite being only one atom thick."
] | [
"You may have heard recently about Graphene, it's a single layer of carbon atoms in a hexagon, it has ",
"many",
" uses and theorised uses. ",
"As for seeing what it looks like, you can find out for yourself using a graphite pencil and cellotape. Though you need a microscope to get a good view still, but a re... |
[
"If a gram of highly radioactive material was made completely stationary in space, could its radiation propel it?"
] | [
false
] | null | [
"Actually this is a really interesting question.",
"The simplest answer is no. In most cases, the atom will just emit the decay products randomly in all directions with a time averaged net of zero. The path at any given moment would follow what we call a random walk.",
"But there is particularly interesting cas... | [
"A random walk will not prefer any direction, and so will end up with an average displacement of zero. However, the ",
" of its displacement will ",
" over time, so that it will get farther and farther away from its starting location, albeit in a random direction."
] | [
"Ah, it's kinda like Brownian motion? Completely random yet still clearly motion."
] |
[
"Why does Windows take longer to copy, say, 1024 1MB files than a single 1GB file?"
] | [
false
] | I was copying 150GB worth of files from an external HDD to a fresh install of Windows and noticed that larger files would transfer a 60-70 MB/s, whereas smaller files would only transfer at 3-4MB/s. What's the logic behind that? | [
"It has to make an entry in the filesystem index for each little file. The drive head moves to an empty space to write the file, then moves to the index to enter it, rinse and repeat. If it can blast one big file, the drive head moves a little at a time rather than back and forth."
] | [
"Although there is some small overhead for each individual file. And, depending on how fragmented the disk is, a large file may allow a continuous write, with little disk rotations - whereas smaller files cannot. ",
"However, the difference shouldn't be in the order of a factor 3. Especially seeing that the 'smal... | [
"Hard drives store data on the surface of a spinning disk. There are read heads that move around to position themselves over whichever part of the disk you try to read from. Reading one big file, the read heads pretty much can just position themselves once and then read all the data as it spins past. If you are ... |
[
"When administering experimental medicine to the seriously sick do doctors / scientists give placebos to patients in order to have a control group? Would this mean that they forgo proper scientific method, or alternatively, let some die without the chance of being effectively treated?"
] | [
false
] | null | [
"Such experiments always go before an ",
"Institutional Review Board",
" to determine if they are ethical. Patients should never be deceived into believing that they have received an active agent and they must consent to any study in which they may be given a placebo. In any study, benefits to others must be we... | [
"Just want to point out that it is very common to control studies with the standard of care and have your experimental group be standard of care plus the experimental drug. This is especially common in cancer trials. Alternatively, you can perform your placebo controlled trial on patients who are refractory to the ... | [
"Placebo based trials have become much less common. In many cases the \"control\" is whatever the standard therapy is, since that's really what you're trying to improve on. Also bind or double blind tests aren't very common because of the problems of informed consent, so most of the time the patient knows which str... |
[
"Do skyscrapers (or other man-made structures) slow the spin of the planet?"
] | [
false
] | I was thinking about how ice skaters and dancers can speed up or slow down by changing how wide or narrow they are, and it struck me that technically, building a structure changes the distribution of weight on the planet at least a very small amount. Does this ever factor in to an equation somewhere or is the effect to... | [
"It ",
" technically affect the Earth's rotation. But the point is that \"miniscule\" doesn't begin to describe how minute the effects are."
] | [
"It ",
" technically affect the Earth's rotation. But the point is that \"miniscule\" doesn't begin to describe how minute the effects are."
] | [
"It would be on par with our ice skater having their hair down, or in a ponytail. ",
"Even that overstates the effect. It would be more like the skater having ",
" hair up or down. "
] |
[
"Does a fridge require more energy when there is something in it?"
] | [
false
] | I realize this might be a stupid question but i can't wrap my head around it. If there is something in the fridge that is already cool (i.e. has the set temperature of the fridge), will having it in there cause the fridge to use more energy? Or is the exchange of warmth from the outside independent from the contents? | [
"This is generally correct. One minor correction:",
"This is assuming that the food is [...] room temperature when you put it in the fridge.",
"'Room temperature' is 'hot' compared to the interior of the fridge. It will take a fair bit of energy to cool that item down to the interior temperature (~3 C).",
"... | [
"Using my uni physics class, we actually calculated this... when there is more in the fridge, there is less space to keep cool. It therefore takes less energy to run a full fridge than it does an empty one. ",
"This is assuming that the food is already cold or room temperature when you put it in the fridge. Hot f... | [
"I have to disagree. While it may be true that it takes longer for the cycle to come on, it will also stay on longer for the same reasoning. You already answered the question when you said that thermal energy enters the fridge at a constant rate. This CONSTANT heat into the fridge means that the fridge only has ... |
[
"Why do we need the Axiom of choice? What does it mean?"
] | [
false
] | More specifically, how does it not follow from the assumption that we can pick an arbitrary element out of a non-empty set? My intuition leads me to believe that AC is obvious, and I can't imagine a scenario in which we cannot pick a choice function for a specific set. I guess at least a part of what I'm asking is, wha... | [
"Your intuition is based on the idea that the objects described by set theory are actually sets. Really the objects described by the ZFC are simply objects which satisfy the axioms of ZFC, and while the goal of ZFC is to describe sets these may be different than you expect.",
"A simpler example of this phenomenon... | [
"(I should preface this by saying that, as my flair indicates, I do not work in logic or set theory, so this is more the perspective from general mathematics than a specialist's view)",
"It depends on what kinds of sets you're imagining, and how we are interpreting the word \"choose\". ",
"A mathematical proof ... | [
"I agree that it is obvious. The problem that some mathematicians had with it is that it leads to some very uncomfortable results, in that it lets you prove that something must exist without actually constructing something. For example, there's a result called Zorn's Lemma which can be proven to be equivalent to th... |
[
"Question regarding Newton's 3rd Law of Motion."
] | [
false
] | My grandfather, my father, and I were having a conversation. Somehow or another our discussion turned to Baseball, and then physics. My grandfather had stated that the faster the pitch the easier it is for the guys to hit a homerun if they do indeed connect with the ball. I asked how that worked and he cited Newton's 3... | [
"One way to intuitively think of it, is imagine throwing a tennis ball at a brick wall. The harder you throw a tennis ball against the wall, the faster it will bounce off the wall. You can think of this in terms of conservation of energy (ignoring small losses of energy due to the amount of velocity imparted to t... | [
"A key observation here is that the bat is much heavier (or more importantly, has more momentum/inertia) than the ball, as evidenced by the fact that it continues its forward swing after hitting the ball.",
"It is this which makes the \"brick wall\" analogy valid."
] | [
"http://en.wikipedia.org/wiki/Elastic_collision"
] |
[
"What's the possibility that life used to exist on Venus?"
] | [
false
] | Ever since I learned about Venus in 7th grade science class, I've had a gut feeling that there used to be life there at some point. But then again, I don't know much about this stuff. I remember the teacher saying it is/was similar to Earth but suffered the green house effect. | [
"Here are the images",
" from the Venera program. They sent several probes there, that landed and took pictures. Venera 14 actually lasted for 57 minutes before succumbing to the conditions on the surface."
] | [
"I don't know about the life part, but there have been ",
"quite a few",
" missions there."
] | [
"and they took pictures!"
] |
[
"If I compressed a spring, bound it in some non dissolvable material, then dissolved the spring in a vat of acid, where would the compression energy go?"
] | [
false
] | null | [
"The block of material in which the spring was embedded would be experiencing stress from pushing back on the spring--when the spring was removed the material could \"relax\" and expand a little bit, which would lower the conformational energy of the material. This would, as the other responder put so succinctly, b... | [
"Heat."
] | [
"The spring is encased in a solid material. Even if it broke it wouldn't be able to move anywhere."
] |
[
"Can people that are deaf in only one ear be able to tell the direction of the source of incoming noise?"
] | [
false
] | We can tell the direction of the person talking to us when our brains measure the different timing it take for sound to reach each of our ears, so for someone who has lost hearing in one of their ears, would they be completely oblivious to this kind of information? | [
"You can always swivel your head to locate the source - sound coming from in front of you sounds different than behind, simply due to the shape of your ear."
] | [
"I am deaf in one ear and cannot tell where sounds come from, no matter the direction. Sometimes I get an inclination about the location of the source, but I am wrong in the majority of these cases. If a loud noise occurs directly in line with my right (hearing) ear, I automatically look to the left. My only recour... | [
"They can have some directionality, but its not as good. Two ears are needed to detect interaural time differences, interaural phase differences and interaural intensity differences. Without this ability directionality becomes very difficult. There are monoaural cues however which help with directionalitiy in the ... |
[
"Why isn’t interchangeable batteries a thing for electric cars?"
] | [
false
] | The biggest complaint I hear about electric cars is the charge times. I always wondered why something like an exchange system for propane tanks, but for batteries doesn’t exist when it could be as fast as filling your car with gas. Biggest reason I can think of is weight, but that could be solved with distribution betw... | [
"The idea of an interchangeable battery is certainly appealing in the search to speed up recharging electric vehicles. However, there are a number of practical limitations and they largely center around the weight and size of the battery packs.",
"The battery pack of a fully electric car can weigh as much as 500 ... | [
"It seems most of these problems do not exist on electric motorcycles. Manufacturers also seem to have already agreed to standardization. Will be interesting to see how that goes."
] | [
"Tesla demonstrated it and implied it would be a thing. There are problems though. Who owns the battery? If you buy a new car and mostly charge at home but decide one day to do a swap on a long road trip and get a four year old battery how do you feel about that? It turns out that DC rapid charge times aren't tha... |
[
"Various bacteria questions"
] | [
false
] | [deleted] | [
"Presumably the exercise you performed was for plant tissue culture, as regular leaf and stem cuttings require no special techniques to prevent contamination.",
"When you wave your hand, how many bacteria are flying off?",
"Probably none. Skin cells and ambient dust may detach, and these may harbor spores, or l... | [
"To follow up on this, the OP may have done things in the hood to prevent mold spores from getting on things. It may also have been an exercise in aseptic technique, as well - for reasons I don't fully buy into, many people avoid passing their hands over growth media or tissue culture plates while in a hood. I pr... | [
"I've used both horizontal flow (conventional) and vertical flow (for the floor-space challenged) for aseptic technique, and it takes a certain presence of mind to never pass the hand between the filter element and open working containers, or cleaned samples. I agree that provided the velocity at the working face i... |
[
"Do spiders take over webs?"
] | [
false
] | Do spiders ever stumble upon another spiders web and occupy it? Or do they always have to build their own? | [
"Once i witnessed a huge spider getting stuck in the web of a super tiny spider. The big one struggled trying to get out while the tiny one slowly creeped on him, wrapping the legs and, what seemed like, started eating him.\nIt was horror watching it due to my phobia to spiders."
] | [
"Argyrodes do this.",
"Argyrodes. Spiders of the genus Argyrodes (Theridiidae), also called dewdrop spiders, occur worldwide. They are best known as kleptoparasites: they steal other spiders' prey. They invade and reside in their host's web even though they can spin their own webs.",
"https://en.wikipedia.org/w... | [
"There’s always a smaller fish? - Not Qui Gon Jinn"
] |
[
"What causes this effect and how can I model it? [Mechanics]"
] | [
false
] | While playing with an 'app' called "Roller Coaster Physics" which determines g-force experienced by the device from its accelerometer, I found the following effect... When I place the device on flat surface (back on the surface, screen parallel to the plane of surface and facing upwards) and spin it such that it rotate... | [
"Here's a question. Is the accelerometer still well calibrated after the spinning? My shot-in-the-dark guess is a sensor error of some kind. Presumably it's sampling significantly faster than the rate of rotation too right?"
] | [
"Just a thought, could it be that at a specific frequency it starts to behave ",
"like a rattleback",
", ie. the device experiences some pitching/rolling (albeit imperceptibly) type modes which dissipate energy in addition to the work done by the frictional couple? Still, it would be unclear why it suddenly sta... | [
"Yeah, I think this is probably it, or close at least. Modelling it piecewise with different values for the frictional couple ",
" fit the data. I guess it's just a \"complex\"/specific interaction possible caused by the quite oddly shaped back of the device. Just interesting that the change in the frictional for... |
[
"If a blind person were to take DMT, would they see anything?"
] | [
false
] | null | [
"From what I've heard ",
"anecdotally",
" it depends on what kind of blindness they have. Someone who's totally blind and has never seen anything ever won't be able to see anything. Someone who has gone blind, is legally blind, or is only partially sensitive to light might get some form of visual hallucination.... | [
"It’s highly dependent on what form of blindness, but I’m assuming you’re asking about the kind where someone is completely visually shutoff including light detection.",
"Yes they would experience the same visions as normal people, as long as the parts of the brain responsible for vision processing are still func... | [
"I know it's not magic, but all that stuff about there being different planes of existence via frequency of vibration seems pretty logical. It's very fun to think about if nothing else. I mean we really don't know that much in terms of the complexity of everything. Were just now starting to see proof for the omnive... |
[
"Nuclear waste: How likely is it that humans will solve the nuclear waste problem in the next 1000 years?"
] | [
false
] | Waiting 100,000 years for nuclear waste to become safe seems absurd to me - almost impossible. Something bad WILL happen in 100,000 years. It seems the best solution would be to transform the waste into less dangerous waste by some means (maybe whats now called transmutation). Is Nuclear science already (today) close... | [
"First off, I think the nature of nuclear waste is actually an asset for nuclear power. Volumetrically, the waste is small compared to other power sources. Secondly, the waste is ALL captured and contained. No other power source captures 100% of their pollutants. Thirdly, nuclear waste has a finite half life. ... | [
"\"Just\" and \"launch it toward the sun\" shouldn't appear next to each other. It's hugely costly in terms of energy to do that."
] | [
"The problem is the anti-nuke movement that raises hell whenever a solution is proposed (and then has the balls to complain that there is no solution)",
"Upvoted.",
"The worst part is this is true about so many other political issues, and this is why nothing ever gets done.",
"People need to figure out what t... |
[
"What causes the optical illusion that makes the prop on this plane look like a series of vertical lines?"
] | [
false
] | My dad took this out the front of the plane. He assures me that the vertical lines you can see are the propeller blades, but neither of us can figure out why it would look like this in the photo. | [
"The iPhone has a 'rolling shutter', which means it scans each line in succession, so in fact does fall into the category I explained above. ",
"Here's",
" another picture of an aeroplane propeller, taken with an iPhone. ",
"Here's",
" how I feel right now."
] | [
"It's not an optical illusion, rather, it's an artifact of how the CCD in his camera works. Take the picture with real film, and it won't look like that."
] | [
"If your camera CCD uses the line-scan technique of recording an image (which I doubt it does), then the camera actually scans down the image. So it gets the top part of the propeller first, then moves down a bit, by which time the propeller has moved a bit, takes another line, then the same again until the whole p... |
[
"Creationists argue that the earth is at the center of the universe due to the presence of discretized redshifts. Can anyone explain what these are, and if this argument has any merit?"
] | [
false
] | [deleted] | [
"There is no merit to the argument. Red shifts (tendency of light towards a lower frequency) result when an emitter of light is moving away from the observer. Similarly, a blue shift (tendency of light towards a higher frequency) results when an emitter is moving towards the observer. The universe is expanding, res... | [
"To add to this, anywhere you go in the universe, you will observe the exact same phenomenon of distant galaxies all accelerating away from you. A naive observer would conclude that because all distant galaxies are moving away from the point of observation, that must mean the observer is the center of the universe.... | [
"Hi _theLittlePrince thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of th... |
[
"Why would Asteroids, Comets, and Meteors cause catastrophic damage only 6-8 miles wide?"
] | [
false
] | To expand on the question, why would these objects cause so much damage? I've read that the objects the size of small towns impacting earth could essentially end life , but how? | [
"They're travelling very, very fast. The kinetic energy of Halley's comet, travelling at Earth's orbital speed, for example, is equivalent to 23 million megatons of TNT. That's quite a lot of energy."
] | [
"It's really not much of a logical step from the idea that a bomb the size of a refrigerator could destroy an entire city."
] | [
"Meteor Crater in Arizona was made by a ",
"meteor about 50 meters across",
"."
] |
[
"Is string theory still a prominent theory in understanding the universe?"
] | [
false
] | I am reading Brian Greene's The Elegant Universe, is String theory still viable? If not, what are some of flaws? | [
"Well, that depends on what you mean by \"viable.\" It's viable in the sense that it ",
" be correct. But it's also not viable in the sense that we may not ever be able to know whether it's correct or not.",
"The thing about string theory is that all the predictions it makes (that we know of) either require imp... | [
"Now, now, let's not exaggerate. A factor of 10",
" is only a ",
" trillion times as powerful. So maybe in a couple years?"
] | [
"String harmonics, a very unique prediction, could be tested by a particle collider approximately one thousand trillion times more powerful than the Large Hadron Collider. (10",
" times more energy)"
] |
[
"According to relativity, can the mass within a black hole ever reach a diameter of zero?"
] | [
false
] | I know that the closer you get to a strong source of gravity, the slower time becomes for your reference frame. Since gravity is an inverse square relation, as the radius approaches zero, the gravity approaches infinity. However, wouldn't an infinite amount of time need to pass before the gravity could reach infinity? ... | [
"I do understand that, as an observer subjected to increasing gravity, I would not notice any time dilation unless I could observe events farther away from the source of gravity. I think I initially had an assumption that once a mass collapses beyond the Schwarzschild radius, no physical force would be able to stop... | [
"A singularity is only formally infinite, it more accurately represents a point/region at which our theories break down. In essence a black hole is sufficiently dense that tiny length scales, which general relativity can't cope with, come into play. More to the point it is the density of matter in the black hole th... | [
"Ah I see that's much clearer. You are correct that the Schwarzschild radius is a point of no return for the collapse. The answer is contained in my first line: we can't answer that question with our theories as they stand. The singularity tells us that GR has broken down, so conclusions about the nature of final s... |
[
"How am I able to comprehend a term completely in my mind, but when asked to define it I struggle to do so?"
] | [
false
] | null | [
"Language is comprehended via repeated experience i.e. you learn --most, probably all-- words from hearing them in context. You can comprehend a term completely in your mind, in the same way you can use correct grammar in your native language without ever studying your language's grammar i.e. without defining it. F... | [
"I look at this from a language perspective (I'm a Speech-Language Pathologist). Receptive language skills (understanding) are developed before expressive language skills. So you are probably understanding the concept, like when a kid correctly knows what an apple is when you say \"apple\" even though it isn't yet ... | [
"Don't think of this as a sign you don't fully comprehend the term. Learning an idea, even to the extent you can apply the idea and use it correctly, is a different skill than learning how to explain the idea to others. Explaining the idea requires not just comprehending the concepts themselves, but also modeling ... |
[
"When astronauts are doing spacewalks, what do they do if they have to urinate or defecate?"
] | [
false
] | null | [
"Hi CatatonicTaterTot thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of t... | [
"'Physics'"
] | [
"Physics "
] |
[
"What does Sunspot 1429 mean for us? Is it a possible concern?"
] | [
false
] | [deleted] | [
"Would like to clarify that any effect seen at the earth is from a solar flare/coronal mass ejection. These energetic events are usually associated with sunspots but the actual sunspot itself has no influence on the earth.",
"Will it possibly eject significantly stronger/more flares than we are used to?",
"Yep,... | [
" Solar Flares can disrupt power grids, communications, and sensitive electronic components in satellites. They can produce beautiful aurora borealis.",
"Health wise they pose no threat except for flying at high altitude (during severe storms polar routes are sometimes shifted to avoid higher radiation)."
] | [
"That should not be taken as medical advice. I have no personal knowledge on the issue - I just found that particular answer."
] |
[
"Why is sunburnt skin warmer to the touch compared to regular unburnt skin?"
] | [
false
] | null | [
"The skin is warmer there because of increased blood flow to the area. UV light causes damage to DNA, and sunburn is basically where the damage has become too severe to repair, and so skin cells start undergoing apoptosis. With all that cell death, the dead cells need to be cleared and stem cells need to start grow... | [
"If you spend a lot of time in the sun (w/out sunscreen) even if you don't get burned the UV radiation will cause a small amount of DNA damage. This damage can build up over time, and eventually lead to cancer.",
"That being said, skin cancer is not one of the 'bad' cancers. Its very easy to detect early (i.e. ... | [
"If sunburn skin is damage to DNA does that mean that I who always gotten tan easy in the summer is more likely to get skin cancer then my wife who almost never get tanned?"
] |
[
"Why is it that a bellyflop hurts more than jumping into water feet first? Surely because the force is spread over a greater area it hurts less."
] | [
false
] | [deleted] | [
"There are a few factors at play here. Part of this is not physics but physiology. Your chest and abdomen are simply more sensitive than the bottom of your feet. ",
"From a physics standpoint, jumping feet first does a few things: first, it means that only your feet actually deal with breaking through the surface... | [
"Surely because the force is spread over a greater area it hurts less.",
"Only if the force is constant.",
"If you go in feet-first you move a bit of water to the side a bit. That doesn't need much energy, you enter the water without slowing down much: A small overall force. In addition the force is at the feet... | [
"The force is not independent of the type of landing. The force is (roughly) proportional to frontal area, and the square of velocity.",
"If you go into the water feet-first, you have little frontal area, and the force is correspondingly small. If you do a belly flop, your frontal area is maximized and the forc... |
[
"Can a pure substance have more then one triple point?"
] | [
false
] | I am aware that a triple point is a point on a phase diagram at which three phases of a substance co-exist. Is is possible for one pure substance to have more then once triple point? | [
"The Gibbs phase rule:",
"f = c - p + 2.",
"For one component (c = 1), the number of degrees of freedom (f) is:",
"f = 3 - p, where p is the number of phases in equilibrium.",
"The number of degrees of freedom cannot be negative. It's zero for a triple point, one for a coexistence curve, and two for a singl... | [
"Yes. A triple point is a point where ",
" three phases meet, it doesn't necessarily have to be a solid-liquid-gas triple point.",
"If you look at the phase diagram for ",
"water",
", there are lots of solid phases and thus multiple solid-solid-solid and solid-solid-liquid triple points.",
"But only one s... | [
"It's also not possible to go above triple. There can't be a quadruple or quintuple point, for example."
] |
[
"How was the exact value for the AU chosen if Earth's orbit around the sun isn't a perfect 0 eccentricity?"
] | [
false
] | null | [
"It was originally just the average of the biggest and smallest distances. Because the Earth moves faster when it's closest to the Sun, this would mean that it spends a bit more time slightly further than 1 AU than slightly closer.",
"However, this isn't the best way to set the value, because it comes down to the... | [
"They wanted to keep consistency with publications written before the standard was set."
] | [
"If the number is kinda arbitrary anyway, they should have settled on nice round 150 000 000 km :/"
] |
[
"Is it possible to keep our brains alive after death?"
] | [
false
] | null | [
"Not at the moment, no."
] | [
"Are you able to elaborate? "
] | [
"It is not currently possible to keep a brain or entire head alive apart from the body. Nor is it possible to \"upload a brain to a computer\", whatever that may mean."
] |
[
"Is it theoretically possible to communicate with the past?"
] | [
false
] | null | [
"No such loophole exists in quantum mechanics, even if non-local behavior is true, no information can be transported this way. On the other end of physics the mathematics of general relativity allow closed time loops, but the situations that cause them require extra physics which doesn't exist in our universe as fa... | [
"\"You could do real-time communication with objects on other plants,\" says Cramer. \"You could put on a virtual reality helmet and be driving your remote dune buggy on Mars.\"",
"I wish him the best, but it's not something most physicists would take seriously as it violates the no-communication theorem,",
"\n... | [
"Empirically, if communication with the past was possible, we would know, because we would have received communication from the future. ",
"\"WHAT DO WE WANT?\" ",
"\"Time travel!\" ",
"\"WHEN DO WE WANT IT?\" ",
"\"That's irrelevant!\""
] |
[
"I'm having trouble grasping the concept of energy."
] | [
false
] | I understand all the equations that I have been given and see how they all relate, but I can't help but feel that it doesn't exist. Energy to me feels like a common variable that is used to relate other variables together. Can somebody help me materialize what energy is? I think if I have a mental image of what energy ... | [
"Energy is not associated with time inversion symmetry, but with time ",
" symmetry -- that is that the laws of physics are the same now as they will be in the future.",
"Energy is the \"generator of time translation\"."
] | [
"In general, conserved quantities result from a symmetry in the problem. For example, angular momentum conservations comes from rotational symmetry (like how a sphere looks the same from all directions). Conservation of energy comes from time ",
" ",
" symmetry. That is, if you replaced time with ",
" ",
",... | [
"You're not the only one confused. Energy, broadly, is the capacity of an object or physical system to do work or create change. It is not directly measurable, so we rely on other measurements like pressure or volume or temperature (which in its self is really a measurement of a different physical quantity) in orde... |
[
"If I were to put a glass of water in a 4 degree Celsius environment (but it \"feels like\" -10 Celsius with windchill), would the water freeze?"
] | [
false
] | [deleted] | [
"The answer is no (assuming you are at sea level). ",
"The wind chill is only a measure of how human's perceive the temperature. But the temperature of the air is still the same. Effectively, a high wind speed means that the air is faster at transferring the heat away from your skin, thus it feels colder. Since t... | [
"In contrast to dry objects, wet objects will get colder than the ambient air, because evaporating water sucks energy out of the object. The final temperature for a wet object in windy dry air is given by this ",
"wet bulb temperature",
" ",
"calculator",
". If the temperature of the air is 4 °C, and the ai... | [
"Yes that makes sense of your dealing with a thermometer. But OP is talking about a glass of water. Therefore evaporative cooling would play a role. The wind would increase evaporation which would decrease the temperature. This article explains that process. ",
"http://www.wired.com/2013/11/how-do-things-cool-wit... |
[
"How does light travel through certain things?"
] | [
false
] | Visible light can travel through glass, but infrared light of a certain wavelength can't. Do the photons hit the atoms of the glass and simply keep traveling? Do they hit the atoms of the glass at all? | [
"Here you go.\n",
"http://www.youtube.com/watch?v=Omr0JNyDBI0"
] | [
"well, in that case, the infrared light doesn't actually promote electrons... it induces vibrations between the molecules."
] | [
"A single atom does have quantized energy states, which means it can only absorb photons of very specific energies.",
"When we get into molecules, we start getting into vibrational motions as well. This alters the energy levels ",
". As a result, each molecule may absorb in slightly different wavelength. See th... |
[
"Can a skincare product with \"only 100% micro-structured, stabilized, electrolyzed water\" really \"kill all harmful bacteria, viruses, and airborne free radicals\" and \"restore the acid mantle?\""
] | [
false
] | null | [
"The scientific term for these kind of brand claims is \"bullshit\"."
] | [
"A free radical is any species with an unpaired electron. They're typically very reactive and do play some harmful biological roles (though, as normal, they also play useful ones). Though \"kill\" is the wrong word, a substance which safely deactivates free radicals might have some merit. But various vitamins in th... | [
"I'm going to call total bullshit on this one. I'm surprised they didn't call it Dihydrogen Monoxide just to throw in some 'more science'."
] |
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