title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"When a ball hits the floor after falling, where does the energy go."
] | [
false
] | the ball doesnt warm up so i cant be heat. also assume there is no air | [
"Is your ball perfectly elastic, perfectly inelastic, or between?",
"If elastic, the ball will change direction and its KE will convert back into GPE. ",
"If inelastic like a ball of clay, then the energy will turn into work (force times distance) that is required to change the shape of the clay as it flattens ... | [
"Tiny shockwaves dissipate out from the point of impact (in both the ball and the ground)."
] | [
"Thermodynamics says it all eventually turns to heat.",
"If you've got a ball hitting a surface, you've got friction and some mechanical motion (eg vibrations that go through the ball and the surface). Friction and vibration also eventually turn to heat.",
"The amount of heat energy needed to raise the temperat... |
[
"Does gravity travel at a constant speed or is it instantaneous?"
] | [
false
] | null | [
"See the FAQ on speed of gravity"
] | [
"Where might I find that on mobile?"
] | [
"The link to the FAQ is in the sidebar - since we don't know what client you're using, ",
"here",
" it is. Cheers."
] |
[
"How are space vessels cooled without convective heat sinks?"
] | [
false
] | I had never considered it before, but it seems impossible to get heat to move away from objects in space without some form of convective current. That means that normal heat sinks and radiators do not work like they do in an atmosphere. How are space ships cooled? | [
"With radiators. ",
"You can read about the ISS's thermal system here.",
"By ",
" here I don't mean like a car radiator where you have a fluid running through pipes with air blown over it to cool it. These devices are emitting heat as radiation."
] | [
"Only at incredibly hot temperatures (think plasma) is radiation efficient. Convective cooling is by far the most efficient for most engineering tools."
] | [
"Seconded. Heat moves in 3 primary ways: conduction, convection (which is really a special case of conduction at the boundary of a solid and a fluid), and radiation. Radiation is heat literally leaving an object as electromagnetic waves (light). There is no convective medium necessary to carry the heat away - it mo... |
[
"Are there any lingering questions in astronomy/astrophysics which no one cares to tackle because, frankly, it will take too long to learn the results?"
] | [
false
] | [deleted] | [
"As I'm sure you're aware, there are quite a few things in the universe that happen on timescales vastly longer than human lifetimes, and often vastly longer than the entire existence of mammals or even land animals. For the most part, if we want to understand how these processes occur over long timescales, we have... | [
"The entire field is hampered by the inability to do experiments, time is one part of the problem but scale is the other. We can't create whole stars or solar systems or galaxies in the lab, and we certainly can't leave them billions of years to evolve to see what happens.",
"As a result the field is built around... | [
"If you're serious about this question and the inlying subject matter, then I would suggest ",
"this",
" book. Its wonderful and covers an incredible array of topical questions in astrophysics."
] |
[
"Why can't we predict weather accurately?"
] | [
false
] | With current technology and satellites, why are we still unable to predict weather with 100% accuracy? | [
"There are a few competing reasons for why weather prediction is not perfect, and never will be:",
" We know the actual laws of motion for the atmosphere exactly; these are known as the ",
"Navier-Stokes equations",
". However, these equations have a property known as ",
"; they can not be solved for exactl... | [
"I once read that even if you had a perfect forecasting model, and perfect observations of the atmosphere from weather stations placed 1 meter apart for the entire depth of the atmosphere, you still could not predict whether or not it would rain a month from now. That's how chaotic the atmosphere is.",
" - I see ... | [
"Despite our vast resources of technology, all the data that would have to be gathered for one area to correctly predict the weather would be immense. It goes from surface temperatures, to air pressures, air moisture, areas of low or high pressure, wind speeds, what the air is like near the tropopause...tons of stu... |
[
"Is the escape velocity of a black hole GREATER THAN or EQUAL to the speed of light?"
] | [
false
] | Obviously, a black hole's escape velocity would have to be at LEAST c, otherwise it would not be able to trap light. My question is whether or not the force of a black hole pulls on anything "harder" than c, whether that would violate universal laws. If the escape velocity of a black hole is precisely c, how come light... | [
"First, \"escape velocity\" is overly simple. It's not a very good description of gravity at this scale.",
"Gravity, as we currently understand it, is caused by deformations in space, contracting inwards around mass. Objects simply follow straight lines along this curved three-dimensional surface.",
"A black ho... | [
"You might like to know that at 1.5 the radius of a black hole the gravity is strong enough that light will actually orbit it.",
"http://en.wikipedia.org/wiki/Black_hole#Photon_sphere"
] | [
"Very interesting. Thank you very much! I love your answer too. I feel like I grasp the idea a little better. At the event horizon, the escape velocity is at c. The space is bent so much at the event horizon and onward that even if there were some \"conscious\" photon that went ",
" and magically turned around to... |
[
"How do the various countries that have English as the main language, end up developing unique accents?"
] | [
false
] | Take Australia and USA. Both countries were largely populated by the British Empire, how did their accents change and develop over the past few century's? | [
"So there's no way to really give a complete answer here. That would require, even just for Australia, much less the US, at least a book-length treatment (certainly for the US it would be several volumes).",
"Ultimately, this comes down to what is called the actuation problem. The actuation problem is basically t... | [
"this is more of an ",
"/r/linguistics",
" question. To take a stab I imagine it is an adoption of slang and shortenings worming their way into formal language and a blend of other exposed accents of ESL speakers. But seriously I am probably way off mark so ask ",
"/r/linguistics"
] | [
"Not just prevalent with anglophone countries/territories "
] |
[
"Imagining vs hearing a sound. Same?"
] | [
false
] | When a person tells you a sentence, does the brain process it the same way as compared to if you imagine the sentence being said to you? | [
"You need to view ",
"Dr. Serenos's videos",
" on this. According to him the human brain has the best overlap between audio and visual areas of the brain. And that human language was originated by this overlap. He said that the auditory senses route data to the visual part of the brain for the best processing. ... | [
"There isn't really much research on this from what I can find. I do know that whenever we get any sensory information (except for smell) it passes through the thalamus in our brain and is then routed to the appropriate spot (in this case the auditory cortex) to be further processed. Imagining in general on the oth... | [
"The point of mirror neurons is supposed to be that they get activated when you either do or observe things (or presumably imagine, though I don't see that get talked about much, maybe I'm just in a different corner of the literature), all of the above. So they should get activated in both cases. Though the thalamu... |
[
"Can some information move faster than light speed?"
] | [
false
] | If the gravity around a black hole is so great that, within the event horizon, nothing including light can escape, then how does the information about the mass of the black hole escape outside the event horizon to tell objects how to move according to the laws of gravitation? The Earth "knows" the mass of the sun to fo... | [
"No, no information is ever carried faster than light.",
"There is no need to carry the information about the mass of the black hole to the outside; this information is already outside, being a geometrical property of the gravitational field.",
"Let's try with an EM analogy. If I have a stationary charge, there... | [
"Quantum Entanglement cannot be used to transmit information",
"https://en.m.wikipedia.org/wiki/No-communication_theorem",
"So while, yes, if you observe an entangled particle to be spin up, then the other will be spin down. But you can't force the other particle to be in a particular state and the other partic... | [
"Thanks for your explanation.",
"I guess it would be a similar idea to say that the information of the total mass that became a black hole before it became one (e.g. before a star's core collapsed, etc.) was available in the gravitational field. When the black hole actually formed, the gravitation field still con... |
[
"Official: r/askScience survey: How and why do you get involved with the community."
] | [
false
] | Hi guys, my name is Charlie. I'm a science communication student at Imperial College London. I'm doing some research on web based science communities, and i thought would be a great case study. If you have 2 minutes, would you mind filling out this form . The mods have given me temporary moderator powers to aid my rese... | [
"Sorry to throw a wrench in your research methods, but you might want to allow people to respond to 'Highest Level of Education Completed' with 'Some University' or 'Some Graduate Work' etc, as I imagine you will find a lot of students on this board."
] | [
"official... hmm..",
"I like science, I like learning; but sometimes there are questions there I want to know but I didn't know I wanted to know and this is a great place to learn those questions (and hopefully their answers) that I would have wanted to know if I had known I hadn't known about them, but for scien... | [
"Thanks a lot - I really appreciate it!"
] |
[
"Why does the limit as x approaches infinity of (1+1/x)^x appear to approach e?"
] | [
false
] | The limit of 1/x as x->infinity is 0, and 1 equals 1, so I would expect the answer to be 1. But, if I plug in 10,000 for x, the limit seems to be our old friend e (2.71828...)! I understand that this is the definition of e in terms of infinitely compounded interest, but I'm not sure why that limit wouldn't be 1. | [
"If A is bigger than 1, then A",
"=infinity, so by your same logic, we should have the limit equal infinity. The fact that it is between 1 and infinity shows that these two opposing \"forces\" kinda balance out somewhere in the middle. Pretty much all interesting limits are like this. In derivatives, the numerato... | [
"A simple, far from rigorous, explanation:",
"Let y = (1+1/x)^x\n",
"Then",
"ln y = x ln(1+1/x)\n",
"where ln is the natural log",
"Looking up the Taylor series expansion of ln from ",
"Wikipedia",
":",
"ln(1+a) = a - a^2 /2 + a^3 /3 + ... \n",
"(note that I've used a in this rather than the x in ... | [
"If you take the limit above as the definition of e it's also circular reasoning though. IMHO a better explanation is showing that the derivative wrt x of (1+x/n)",
" goes to (1+x/n)",
" as n -> infinity and then defining e as this function at x=1"
] |
[
"There are certain words to describe how responsive certain objects are to physical influences; ie: the buoyancy of an objects describes how well it will float, aerodynamic how well it will fly. What is the term to describe how well something will bounce? I'm looking at you physics peoples..."
] | [
false
] | null | [
"Coefficient of restitution",
" is what you are looking for."
] | [
"It has a lot to do with how it transfers energy. The other posts cover a bunch of possible words, but the reason there isn't something beyond bounciness is that it is a combination of all these other properties of the material.",
"You can have something that is highly elastic but returns to its shape very slowl... | [
"Apart from bouncing, other quantities that describe the properties of a material are e.g. viscosity and tensile strength, or in the realm of polymers, crystallinity and toughness."
] |
[
"Why is human (and a lot of animal) vision centred around the 400-750nm wavelengths of light?"
] | [
false
] | We have 3 come receptors, one for blue around 450nm, one for green around 550nm and one for red around 670nm. Why are they in this region, and why are they so close together? Would it be the difficulty in focusing longer wavelengths or the lack of biological mechanisms for other wavelengths? Or just pure chance for to ... | [
"Dont forget that our atmosphere is mostly transparent in these wavelengths. ",
"if our atmosphere was opaque in the current visible range we would see something else",
"http://www.eso.org/public/archives/images/screen/atm_opacity.jpg"
] | [
"The peak wavelength of the Sun is around 500nm, so eyes have evolved to see in this region as it is the brightest.",
"\nIf, for example, the Sun had a peak wavelength of 1nm, you can assume eyes would have evolved to see in the x-ray part of the spectrum."
] | [
"I'll quote from ",
"handprint.com",
" (emphasis mine if you feel like skimming)...",
"As the ",
"diagrams",
" at right show, ",
", including liquid and water vapor — and the large bead of mostly water, the vitreous humor, that inflates the eye and sits between the pupil and retina. Human light sensitiv... |
[
"What would be the best way to start making another planet hospitable?"
] | [
false
] | If we had to make another planet hospitable eventually, what would the best course of action be? This barren planet has a similar atmospheric pressure and temperature. Think Dune. For example: Bring a lot of salt water and let it evaporate into the atmosphere. Plant resistant shrubs. Bring lots of varieties of bac... | [
"Venus is ",
" habitable. You just have to abandon the idea of living on the surface.",
"The atmosphere is so dense, it is more similar to the Ocean, not the air on Earth. Fish don't live on the abyssal plain either. At about 50km height, a bit to the poles, you have comfy 20°, a bar of pressure and ample suppl... | [
"If the necessary \"starting materials\" for an Earth-like biosphere aren't on the planet to begin with, it's far into the realm of science fiction to bring them there. The energy necessary to transport enough water to a new planet to get it \"up and running\" is not really within the realm of any technology we cur... | [
"Who the hell needs hydrogen",
"Well... humans."
] |
[
"Was my friend's soap experiment valid?"
] | [
false
] | My friend who is a nurse told me a story of an experiment they did while in nursing school. They covered their hands in germs that would glow green and then did several different trials of washing. In one trial they would use soap. In another trial they would just use water and a lot of scrubbing. Their results were... | [
"this is not a good experiment for multiple reasons.",
"Here are a few examples, you can probably come up with more yourself.",
"Doing several trials of washing could lead to them becoming better ( or worse ) as they washed over and over, and similarly there is not way of ensuring your technique is the same eve... | [
"From an experimental design point of view it is a poor experiment since there is no positive control - no set of conditions where you ",
" you will be able to remove the green from your hands. You approach this with your suggestion of an alternate explanation. ",
"Its impossible to say whether the bacteria th... | [
"|Why do we even use soap at all if that's the case?",
"Plain old soap (not anti-bacterial) is used to break the bonds that dirt and grime have with the your skin and makes it easier to wash away not to kill bacteria, just hopefully to rinse it away with the suds."
] |
[
"Couple questions about Black Holes"
] | [
false
] | So I was reading this thread and had some questions and couldn't reply. Just 3 for now but I might ask more later. As a spaceship approaches the event horizon, what is its acceleration? An observer on earth would see the spaceship red-shifting and increasing in speed for an infinite amount of time, but never reaching ... | [
"Acceleration is not a well defined quantity in GR. There is a generalized quantity that becomes acceleration in flat space time, but you didn't specify from which observer to measure acceleration. From the point of view of the spaceship it is in free fall and can't feel any acceleration. ",
"Yes, as the ship app... | [
"The boundary of a (static) blackhole, the event horizon, is defined by its Schwarzschild radius, ",
"http://en.wikipedia.org/wiki/Schwarzschild_radius",
" . A spaceship doesn't have to be accelerating much at all (either with thrusters or by the gravitational attraction, or the sum [e.g. thrusting to move away... | [
"From whose frame of reference? From an outside observer at rest w",
"/r/to",
" the black hole, the ship is accelerating ",
" from the black hole. From the ship, it's a harder question - one that I cannot with any confidence answer.",
"Yes. (Also, it's a general relativity question.)",
"What mechanism ... |
[
"Actual Explanation for the Recent \"Magnetic Monopole Discovery\"?"
] | [
false
] | [deleted] | [
"They haven't found actual magnetic monopoles, only things that behave like they'd expect monopoles to behave if they ",
" exist, under conditions that are analgous to an E-M field that assumes monopoles exist.",
"It's kind of like how, in a semiconductor, you can pretend 'electron holes' are conducting particl... | [
"These monopoles do not violate the div(curl( something )) =0 condition. As the abstract says:",
"Monopoles are identified, in both experiments and matching numerical simulations, at the termini of vortex lines within the condensate.",
"The vortex acts like a thin solenoid, which carries magnetic flux into the... | [
"The \"monopole-like behavior\" is only valid for a surface that is much larger that the diameter of the solenoid, and much smaller than the length. That's why I specified a \"long, thin solenoid\" - to make this possible. I'll look for an image later tonight.",
"The ",
" div(B) is always zero, but in this si... |
[
"How do you determine the age of living plants that aren’t trees?"
] | [
false
] | We recently visited Namibia , where the grows. Supposedly to ages of >2000 years. How would they establish this for a living example? It doesn’t have a stem where you could count rings. | [
"I work in Namibia and though this isn’t my area, I’ve worked alongside scientists who have dated Welwitschia. There’s kind of a woody stump in the middle of the two leaves (yes there’s only two…they just get shredded over time). The leaves and layers of new wood grow outward from the edges and leave behind dead wo... | [
"Through radiocarbon dating. It is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. It is based on the fact that radiocarbon (14C) is constantly being created in the Earth's atmosphere by the interaction of cosmic rays... | [
"The two most common strategies are carbon dating, as somebody has already explained, and estimating the age on the basis of size, where that's possible. Most plants start from a single seed, which then grows roots in one direction, and shoots in the other. If you can estimate the growth rate of the planet, and the... |
[
"If a superconductor has 0 resistance, will a current not cause the superconductor to heat up?"
] | [
false
] | I'm thinking about how if you have a very high current going through a small wire, the wire heats up and starts to glow orange, but if a superconductor has no resistance, then none of the energy is lost, so no heat would be produced, right? Or am I missing something? | [
"With small currents, no heat would be produced. In fact, in a superconductor, you can have a loop of wire with no battery in it but with current flowing. However, there is a maximum current at which materials cease to be superconducting, which would cause energy to be lost to heat at large currents."
] | [
"That's how high field magnets for MRI are built: a coil of superconductor is placed in a liquid helium (very cold) tank to be kept at the right temperature, and current is then sent in the coil. A current in a coil generates a magnetic field. When the field strength of high enough you stop injecting current. As th... | [
"There is many way to jump start a persistent current. You can cool a loop of wire down, and induce a current by magnet."
] |
[
"Speed of light question."
] | [
false
] | Does light actually travel slower than the speed of light inside an atmosphere like Earth's versus when traveling through the vacuum of space? | [
"Kind of. The speed of light is ",
" c, even through mediums. However, in conditions like atmospheres, photons are occasionally (or in some materials, very commonly) absorbed and re-emitted. This results in an \"apparent\" slowing down of light. However, in all instances where photons are in motion, they will alw... | [
"This. Light on the whole will generally travel more slowly in a medium, but the individual light particles have no idea what medium you're in; they always travel at c."
] | [
"The speed at which light propagates through transparent materials, such as glass or air, is less than c. The ratio between c and the speed v at which light travels in a material is called the refractive index n of the material (n = c / v). For example, for visible light the refractive index of glass is typically a... |
[
"What issues would be be worried about if we were experiencing global cooling, instead of global warming?"
] | [
false
] | With global warming, there are many interesting consequences that I never would have considered. What would these be if the planet was cooling? | [
"Then you'd be wondering about whether we'd be heading for a full scale glaciation, such as the most recent one which ended about 0.1 MY ago, in the Pleistocene. ",
"Such events can begin rather suddenly, geologically speaking, and would eventually lead to snow failing to completely melt in northern Canada, Scand... | [
"The carbon cycle is disrupted, volcanoes still exhaust the same amount of CO2 however there is much less photosynthesis going on so atmospheric CO2 levels rise."
] | [
"Yep!",
"And that is a large part of how we can tell these planetary glaciations even existed: the whole process throws the carbon isotope ratio of carbonates completely out of whack, leaving a glaring isotopic anomaly in the geological record. [well ... that and the equatorial glacial sediments topped by warm wa... |
[
"Where does the potential energy come from, in osmosis?"
] | [
false
] | So, when osmosis happen the molecules of water move from one side of the semi-permeable membrane to the other, in some cases it moves in a vertically up direction, seemingly defying gravity and gaining potential energy. So, since potential energy cant just show up out without an instigating factor, due to that being a ... | [
"Good question. This arises from thermodynamic requirements for entropic increase over time in a system. The statistical mechanics of “stuff” bouncing around quite literally result in the dispersal of “stuff” evenly throughout an area. This means, if I have a lot of something on one side of a membrane, and there is... | [
"The existing answers have correctly noted that this process depends on the ",
"chemical potential",
" and on the ",
"Gibbs free energy",
" G = H - TS, where H is enthalpy, T is temperature, and S is entropy. I'll note that the ",
"chemical potential",
" itself ",
" the molar Gibbs free energy, ",
"... | [
"There is gravitational potential energy, but there is also something called \"chemical potential\". Basically, the water molecules are happier on the other, upper side of the membrane (lower chemical potential) and therefore they are moving across the membrane, even though this incurs a cost in gravitational poten... |
[
"A teacher showed us Masaru Emoto's study on frozen water drops when given \"good\" and \"bad\" emotions. True or False?"
] | [
false
] | [deleted] | [
"What kind of class was this? ",
"Emoto is a faker",
"."
] | [
"This man is making an extraordinary claim. There is no known mechanism that would explain his results, and they run counter to what we currently believe to be true about the natural world. Therefore, his evidence has to be of an extremely high quality, and it would have to be independently verified and replicated ... | [
"That guy is associated with a company that sells small jars of water for $100 each. The website is full of fake science.",
"Those photographs were hand-picked to show whatever it is he intended to show. Emoto admits to this:",
"Emoto freely acknowledges that he is not a scientist, and that photographers are ... |
[
"/r/AskScience, please give me websites I can look at to learn more about science in general"
] | [
false
] | Hi! I have a problem. The problem is, while I'm scientifically sound on some subjects, I am scientifically illiterate on others. Please, guys, I want how-to guides, simple science websites or easy-to-understand-for-a-layman sites that will help me learn science! I would like to learn specifically about these topics: -H... | [
"IANAS and I'm sure at least one will quickly tell me how wrong I am, but I think wikipedia is absolutely fantastic for this purpose"
] | [
"You're probably better off with books than with websites."
] | [
"The average book store around here does not carry them, only the college and university grade books that are a trillion dollars each and contain material way above my level.",
"What about e-books? This site has a shitload of textbooks (and some solution manuals) in pdf format:",
"http://gen.lib.rus.ec/"
] |
[
"If microwaves are \"non-ionizing\", how does a grape create plasma in a microwave oven?"
] | [
false
] | Is non-ionizing radiation really incapable of ionizing ANY molecule? Edit: | [
"Ionizing radiation when it comes to photons refers to the ionization of an atom by Compton scattering or the photoelectric effect. These both are the effect of a single photon interacting with an electron and transferring enough kinetic energy to knock the electron out of its atom's potential well. By conservation... | [
"To answer your secondary question: No. Non-ionizing radiation might be able to break very, very weak bonds, but is called non-ionizing because for most organic compounds, things we actually care about, it can't. What it can do, however, is generate electrical flow, due to Photons being electromagnetic carrier part... | [
"In case you mean the radiation of a photon has 1/x th of the ionization energy so you use x photons to get there then no. This is the classic approach which the photoelectric effect has disproven. Intensity of radiation/number of photons has no effect as long as the energy of a single photon is not sufficient for ... |
[
"Over the course of its existence, has the Earth's mass increased in any significant way from collecting meteorites?"
] | [
false
] | [deleted] | [
"https://en.wikipedia.org/wiki/Atmospheric_escape",
"According to that, 3 kilograms of hydrogen and 50 grams of helium per second.",
"So no, not anything significant in terms of our atmospheric composition (Mostly nitrogen and some oxygen), but that's a decent volume of air, and certainly not nothing.",
"Reme... | [
"https://en.wikipedia.org/wiki/Atmospheric_escape",
"According to that, 3 kilograms of hydrogen and 50 grams of helium per second.",
"So no, not anything significant in terms of our atmospheric composition (Mostly nitrogen and some oxygen), but that's a decent volume of air, and certainly not nothing.",
"Reme... | [
"Depending on how far back in time you're thinking about, this question is pretty easy to answer. Because in the very early stages of the formation of our planet, it was struck by lots and lots of meteorites. In principle you could argue that Earth is mainly made build up from meteorites ( though it gets tricky wit... |
[
"In reference to a FAQ, WHY are Quantum computers faster at solving certain categories of problems?"
] | [
false
] | null | [
"Hello,",
"Your question is too broad, and the answer is \"",
"\". Since the answer is as vague as the question broad, I doubt it'll be satisfactory; in which case, I would suggest making the question more specific, e.g. for a specific problem you have in mind. Otherwise, reading up on some examples of quantum ... | [
"Could you explain what quantum algorithms are and what makes them different?"
] | [
"I'm on vacation atm and thus I can't, sorry. You should submit it as a question! Some of our experts would gladly answer it!",
"Cheers."
] |
[
"Why were mammals larger during the Ice Age?"
] | [
false
] | It seems a bit counter-intuitive. A larger animal needs more calories to survive and stay warm. It was much colder, and there was less food to go around. It's also harder to circulate warm blood if your heart is further from your extremities. Seems like the most successful creatures during this period would have been v... | [
"It is not so much that terrestrial mammals were big back then, it's that they're small now. Mammals ",
"increased in size following the Cretaceous-Paleogene extinction and maintained that large body size",
" for nearly 30 million years years. Then there was an ",
"extinction at the end of the Pleistocene",
... | [
"StringOfLights hit the most important points but I'd like to stress that every animal is a different case and the more you look into a particular species you'll see different or additional reasons for the size they had. While an old source, 1968 Björn Kurtén's ",
" (and I guess its companion New World book, ",
... | [
"That edit was exactly what I was going to point out <3"
] |
[
"How is an “increased risk of cancer” actually measured?"
] | [
false
] | The news today showed an article regarding processed food being shown to “increase to risk of cancer by 12%” (or words to that effect). How do scientists measure the increased risk of something?? | [
"They measure it. Group A has 10% cancer rate, without the variable. Group B has a 11% cancer rate WITH the variable, it may be concluded that the variable increased the cancer rate by 10%, if ones scientific process has effectively eliminated all other confounding variables. "
] | [
"Agreed, except in your example, one would say it elevated the risk by 400% or by 8 percentage points. Not by 8%. "
] | [
"Agreed, except in your example, one would say it elevated the risk by 400% or by 8 percentage points. Not by 8%. "
] |
[
"Why does water freeze at the surface?"
] | [
false
] | [deleted] | [
"The water density does not vary linearly with the temperature. At about 4c the water is the heaviest, so it drops at the bottom.",
"Also, the water is usually hotter than the air during the winter, because it was warmed up during the summer and it retains heat pretty well. So the water at the top comes in contac... | [
"This is the right idea. Water reaches maximum density at 4 degrees celsius (~39 degrees F). Water also has the unique property of being less dense in a solid phase (ice) than a liquid phase. This is why ice cubes float in beverage glass and why icebergs float in the ocean. Odd as it may sound, your question is... | [
"Also consider that the soil stays a fairly constant 50 degrees F or so, year round several feet below the surface in cooler regions."
] |
[
"Since gravitational fields slow down time, does that mean that time runs \"faster\" in the empty space between galaxies than it does on Earth?"
] | [
false
] | If so, how much? And does this also mean that galaxies are pockets of space where time slows down compared to most of the universe? | [
"I'm not sure what you mean by the utility. Plugging in numbers for the above for the mass of the Earth, the radius of the Earth, the gravitational constant, and the speed of light, I get a factor of:",
"sqrt(1-2",
"6e24 / (6.371e6 * (3e8)",
" = 0.999999999302046... in WolframAlpha.",
"So, for every dt = 1 ... | [
"Correct, and yet useless to me. Though, even if it were an answer measured in microseconds, the utility would be questionable."
] | [
"Correct, and yet useless to me. Though, even if it were an answer measured in microseconds, the utility would be questionable."
] |
[
"How long could a human live if he/she has constant organ transplants?"
] | [
false
] | So I know that humans succombe to mortality for several reasons including (but not exclusively), hearth failure, disease of many organs, deterioration of brain or nervous system, diabetes, cancer, and many others. However, with advancements in science, doctors can replace many organs (including the heart), almost anyth... | [
"This is a problem of practicality and quality of life.",
"I've participated in upwards of 50 transplants for heart/heart lung and the surgeries, even today, have poor survival rates out of the OR alone. Their is a list of survival rates for lung-transplant ",
"here.",
" Then you need to consider the other ... | [
"I don't know of anyone who would be able to give you that estimate. That's the really tough part about medicine and the future, we could discover something in the next 5 years that changes everything, but we don't know about that yet.",
"Also",
"respirator",
"No such thing, ventilator is typically what some... | [
"But in the hypothetical (but theoretically possible) future organ rejection will be a non-issue due to either made to order lab grown organs or cloned organs harvested from an animal host. This is a process currently in the proof of concept phase, but is absolutely possible if not likely. ",
"Second thing is the... |
[
"Does food stay hotter if I bring it to heat over a longer period of time?"
] | [
false
] | As subject really? Say I bring a pot of pasta to the boil over a 30 min period vs a 5 minute period - will it retain its heat for longer? | [
"No, the factors that determine the rate at which food cools down are the relative temperature of the surrounding area and the container. It'll cool off faster in a cooler room, and a metal bowl, and slower in an insulated container and a warm room. ",
"Some foods may seem to cool off faster if heated faster, but... | [
"No. By Newton's Law of cooling",
"\n",
"https://en.wikipedia.org/wiki/Newton%27s_law_of_cooling#Newton.27s_law_of_cooling",
"\nThe rate at which an object cools is proportional to the difference between the temperature of the object and that of its medium/environment. Whether it takes a day or 5 minutes to... | [
" It doesn't matter how it got that way, only what its environment is like."
] |
[
"If the sun is made up of hydrogen and a somewhat stable nuclear fusion, why can’t we keep thrusting plasma into it like a log into fire to keep it from consuming itself out?"
] | [
false
] | null | [
"The sun contains over 99% of the mass of our solar system. We could never put enough material into the sun to make a difference in its evolution."
] | [
"So basically we are not a type of civilization that could harness power to do that. We cannot sling shot dead planets into it cause even if hypothetically we could find a way to, in theory it wouldn’t help it anyways?"
] | [
"Even if you collected all the rest of the matter in the solar system and thrust it into the sun, you’d change its mass by a fraction of 1%."
] |
[
"I have been told that if the average mass of our universe was greater, matter may well be comprised of the heavier leptons and quarks. How much heavier would our universe have to be for this to happen?"
] | [
false
] | [deleted] | [
"The only situation I'm aware of is in environments of extreme density of the particles they decay into because of the ",
"Pauli exclusion principle",
". For the strange quarks the only sufficient environment I know of would be quark stars (if they exist). I suppose muons might not decay inside a white dwarf.... | [
"I don't see how this can possibly be true. He must have been confused.",
"Strange quarks have strangeness; could there be protons and neutrons made out of strange and charm quarks? ",
"There are particles like proton and neutrons that include the heavier quarks (",
"baryons",
"), but they decay very rapid... | [
"Do we have any idea whether or not there are circumstances in which they do not decay quickly?"
] |
[
"Why did the fact that all electrons are the same, is special, aren't all elementary particles the same?"
] | [
false
] | null | [
"Indistinguishability applies to all types of particles, not just electrons."
] | [
"I said that too but why is it special",
"\nFrom the video:",
"The 'One-Electron Universe' was motivated by an odd fact about electrons that had troubled Wheeler: ",
"that they are all identical. ",
"Exactly the same charge, exactly the same mass, exactly the same everything, ",
"there was no satisfyin... | [
"Electrons are not special. If you’ve read somewhere that that’s the case, then whatever you read is wrong."
] |
[
"I've heard about efforts to eliminate mosquitoes by genetically modifying them to be sterile. How would the gene spread if the individuals with this gene couldn't have any offspring?"
] | [
false
] | null | [
"I’m not sure if this is exactly what you are referring to, but there is a method used called Sterile Insect Technique where large numbers of insects (usually male) are irradiated in order to sterilize them, then they are released in the wild. Females who mate with the sterile males will produce no offspring, there... | [
"There are two approaches in use. The first is as you describe - GM males are deployed which cause all offspring to die as larvae, and hence drop the population. They have to outcompete the normal males to be effective, so you need lots of them. Each year you would redeploy if the disease-causing population reco... | [
"If you could genetically alter mosquitos so only one sex (females for example) became sterile, populations would drop quickly. Making both sexes sterile would prevent them from spreading genes like you mentioned."
] |
[
"Why don't you get thunder from a Tesla Coil?"
] | [
false
] | I'm using for reference. Why doesn't the bolt that shoots from his hand at 40 seconds create some form of thunder? | [
"It does, and you can hear it as a buzzing/crackling sort of noise in the video. (It isn't clear just how loud they can be from the video, though.) Thunder from a lightning bolt sounds different because the scale of the bolt is vastly different, and that's a single bolt whereas a Tesla coil typically emits a consta... | [
"Tesla coils can be operated in single-shot mode, producing a single spark \"on command\". This will create a loud noise, and so in this situation we have something very akin to lightning + thunder."
] | [
"The usual Tesla coil arcs grow slowly, so they don't create the rapid expansion of air needed to make a loud \"Bang.\" Also the arcs are normally continuous rather than a single impulse.",
"Additionally, real thunder is created by a spark which can be KM in length. Sound only travels at around 340M/S. There'... |
[
"Since the perceived gravitational force at the center of the Earth is nearly nothing, is the center of the Earth experiencing time flowing faster relative to the surface of the Earth?"
] | [
false
] | null | [
"There was ",
"a paper",
" recently that calculated this explicitly, it turns out the center of the Earth is about 2.5 years younger than the surface.",
"edit: ",
"free pdf"
] | [
"It's confusing because physics is right and your common sense is wrong. Time can move at different speeds for different observers. Look up \"time dilation\" in the context of special or general relativity."
] | [
"The perceived gravitational force may be nothing, but you're still lower in the Earth's gravity well, so time flows slower there.",
"The gravitional potential is high - so time flows slower - but it's also just as high nearby, so you don't feel any gravitational force."
] |
[
"What's the significance of prime numbers?"
] | [
false
] | Why is a number that can only be divided by 1 and itself so important? Does this mean anything to the advancement of humanity or is it just a "cool thing" about numbers? | [
"The Primes are the building blocks of all numbers, and as such, they have many unique and critical properties. By, \"building block\", I mean that any positive integer can be written as the product of primes (\"The Fundamental Theorem of Arithmetic\"), which, as I am sure you can tell by its name, is pretty impor... | [
"I mean that any positive integer can be written as the product of primes (\"The Fundamental Theorem of Arithmetic\"), which, as I am sure you can tell by its name, is pretty important.",
"It can be written uniquely as a product of primes. The uniqueness is really the important part of the theorem because otherwi... | [
"This video",
" is what you need to watch."
] |
[
"Why is laser communication faster than microwave/ radio communication?"
] | [
false
] | null | [
"Higher frequency means shorter wavelength.",
"Since the speed of both waves is the same, for a given time period the laser can fit more complete waves.",
"Something like so:",
"Laser:\n",
"Radio:\n",
" ",
" ",
"Here, ",
" is the length of the wavelength of a laser and ",
" is the length of the wa... | [
"This is the major effect.",
"But also consider that radio (up to a few hundred MHz) uses a shared medium, whereas optics is mainly confined in optical fiber. ",
"If I have a radio link with 100 MHz carrier, and I use this to transmit 100 MHz of bandwidth, I'll be interfering with all the other radio users with... | [
"Actually, if you turn a \"microwave\" signal on and off at, say, a Terrahertz rate, you're no longer transmitting microwaves :)",
"To understand this, consider a sinusoidal microwave signal",
"cos(omega_m t).\n",
"Now I turn it one and off at a very high frequency ",
"Omega",
", so the resulting signal i... |
[
"In the past have there been mountains taller than Mt Everest? Is it possible to work this out?"
] | [
false
] | null | [
"It's possible to estimate the height based on what we know of how fast continents moved relative to each other. ",
"Everest is pretty much as high as mountains can get on Earth. Other mountains might have been a little taller, but not much. The mountains of what is now Norway, for example, were once as tall as ... | [
"You can argue that there are taller mountains than Everest today. Everest is the tallest in terms of height above sea level. The sea is far from Everest. The tallest mountains in terms of height above local terrain, above sea floor, and above the center of the Earth are all other mountains. ",
"The highest mou... | [
"It's the same with the Appalachia mountains. They might be part of the same chain. They're among the oldest mountains in the world and used to be Himalayan in size."
] |
[
"Why didn't the Big Bang form heavier elements?"
] | [
false
] | I've read that virtually all heavy elements are created when stars explode (or through other stellar processes of an explosive nature). If this is the case, why didn't the Big Bang itself cause the creation of heavy elements? I understand that it wasn't an per-se, but with so much matter clumping together so quickly, w... | [
"The fusion of nuclei in the hot early universe is referred to as big bang nucleosynthsis. It occurs while the universe is hot enough and dense enough for nuclear fusion to happen, but while the universe is cool enough such that gamma rays don't immediately disassociate the nuclei. This means that big bang nucleosy... | [
"Most lithium, beryllium and boron produced today comes from cosmic ray spallation. Essentially a cosmic ray hits a heavier element and breaks it into smaller pieces.",
"http://en.wikipedia.org/wiki/Cosmic_ray_spallation",
"If you are talking about the entire universe, is it possible that at least one carbon-1... | [
"Woah.. So what existed before hydrogen? Quarks?"
] |
[
"Is matter an energy state ? If so, can this apply to everything in the universe like information ?"
] | [
false
] | null | [
"Well, actually mass is an energy state.",
"\nEspecially because mass is well defined, and matter is a very loosely defined term.",
"\nFurthermore anti-matter follows the same mass-energy equivalence as matter, so mass is really the better term to use.",
"You also have to keep in mind that \"energy\" is only ... | [
"I always figured mass as condensed energy. Loosely figured. ;)"
] | [
"\"Energy\" is not a real thing though, thus it cannot possibly condense.",
"\nEnergy always has to assume one form or another. As I said before, it essentially is nothing but a mathematical tool."
] |
[
"What ELSE can microwaves do to your food?"
] | [
false
] | I know you can heat up food in your microwave, because the waves interact with water bonds in such a way as to "excite" them. But I also know you can make plasma with a candle or grape, make CDs explode, etc. etc. I read somewhere that microwaves cause powerful elictric and magnetic fields which potentially rip apart n... | [
"I can tell you from the energetics, that the energy of microwaves (",
"10",
" eV",
") That this is not enough energy to ionize things right away. It gains its power to do these other effects due to its intensity. So it literally keeps dumping the energy in and heats whatever it is up, until the things are so... | [
"ok thanks. Here is a secondary clarification. You mentioned compounded energies. Would it affect polar molecular structures more since there is induced fields? I feel like things other than metal will be affected at that high of an energy output."
] | [
"Chemist here.",
"As far as everything I have read on the subject goes you are perfectly fine microwaving your food. Any loss in nutritional value comes with simple heating (ie, would happen if you boiled it or steamed it or used any other less tech savvy methods for heating) and often times (yes OFTEN) microwavi... |
[
"What happens to the magnetic field of a magnetar if it collapses into a black hole?"
] | [
false
] | My thoughts: I suspect that the external fields release and snap away in a great explosion kinda like solar flares. The internal fields are swallowed by the event horizon. I was wondering because of the no hair theorem states that a black hole can only have mass, charge, and momentum. If you have a charge in motion, ... | [
"First, a clarification:",
"the no hair theorem states that a black hole can only have mass, charge, and momentum",
"The no-hair theorem (not really a theorem, actually -- a full proof does not exist) states that a black hole can be ",
" its mass, charge, and ",
" momentum. That doesn't mean it can't have ... | [
"As the stellar matter is accreted onto the BH [black hole]..., the external magnetic field which was anchored on the stellar surface becomes disconnected, forming closed magnetic-field loops which carry away the electromagnetic energy mostly in the form of dipolar radiation.",
"So... a huge burst of EM radiation m... | [
"Thank you for correcting me. ",
"If I understand correctly, the derivable quantities that you refer would be things like momentum (from mass), magentism (from charge), etc.",
"That makes more sense.",
"While the symbols I dont really get as astrophysics isnt my field, it was pretty cool to see runge kutta m... |
[
"How and why do antibonding orbitals form?"
] | [
false
] | Hybridization is a generally good theory, but it doesn't explain properties like magnetism. Molecular Orbital theory apparently explains it better because of these antibonding orbitals, but how and why do they form if they're higher energy and unstable? I heard it has something to do with the fact that electrons are de... | [
"Hybridization is a generally good theory, but it doesn't explain properties like magnetism.",
"Valence-bond theory actually explains the paramagnetism of oxygen, if that's what you're referring to. (and has since the start, it's in Pauling's \"The nature of the chemical bond) It's a common myth though, so anyway... | [
"How does valence bond theory explain the paramagnetism of oxygen?"
] | [
"You need to use a three-electron bond. Shaik dug into the history of this myth in ",
"this paper",
" (also in his VB book). Seems like the whole thing that it supposedly failed there, all started with an offhand comment by Lennard-Jones."
] |
[
"Why don't rockets use variable geometry nozzles like on military turbojets?"
] | [
false
] | null | [
"Because fundamentally, military turbojets and rockets are meant for radically different flight profiles.",
"In a military jet, you're going to be in the air for a reasonably long period of time - generally at least a couple hours, if not longer. During that whole time, you're stuck carrying your engine around wi... | [
"It's been considered. A variable geometry rocket nozzle could be more efficient over a range of air pressures (and thus altitudes). However it adds mass and cost. The former reduces the vehicle performance somewhat and may partly undo the benefit of the better efficiency, while the latter is important considering ... | [
"Yes, and even small changes in mass cause large changes in extra fuel weight required to support the mission."
] |
[
"Does a clean/waxed car get better fuel efficiency than a dirty car?"
] | [
false
] | null | [
"Technically, yes. Vehicle manufacturers design their cars with certain degrees of aerodynamics. Allowing the CSR to get dirty not only effects the aerodynamic output, but if its dirty enough, the dirt adds weight. I say technically though because the differences tend to be miniscule and unnoticeable unless you are... | [
"Thank you for the answer!"
] | [
"As for commercial jets, they can accumulate a couple hundred pounds of dust on the exterior over time which does have a measurable effect on fuel economy. I'm not sure about the effect to aerodynamics though. "
] |
[
"If neutrinos do not interact with regular matter, how would they behave in the presence of a black hole?"
] | [
false
] | null | [
"Neutrinos do interact gravitationally, as any form of energy-momentum ",
" do, and so they fall in black holes."
] | [
"Also they do interact with regular matter, but it's only rarely. For example the Kamiokande detector with 50,000 tons of water experiences only about nine collisions from solar neutrinos per day."
] | [
"And to clarify, neutrinos do interact through the weak force too."
] |
[
"Why does paper turns transparent when i smear fat/oil over it?"
] | [
false
] | null | [
"The water or oil act as ",
"index-matching medium",
" for the paper. This simply means that the water or oil have a refractive index similar to that of paper, or least more similar than the refractive index of air. This (partial) index matching reduces scattering and allows more light to be transmitted through... | [
"So, similarly to tape applied to frosted glass causing it to become transparent, neat!"
] | [
"In fact, this is the premise for H. G. Wells' ",
". Obviously applying this to the whole human body doesn't work at all, but he gives a nice explanation of the effect:",
"\"Precisely,\" said Griffin. \"But consider: Visibility depends on the action of the visible bodies on light. Either a body absorbs light, o... |
[
"Is there an end to the light spectrum?"
] | [
false
] | I know that there are many wavelengths past what is visible, but does the spectrum go on forever in either/both directions? If there is an end to it, how do we know that is an end of the spectrum and not simply a place that we can no longer observe it? | [
"According to the nice folks at NASA, ",
"http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970412e.html",
"\nThere is a academic limit at 10",
" Hz because beyond that the physics stop making sense. "
] | [
"That's not accurate. You can't ",
" wavelengths larger than the observable universe. But they can exist. This idea is important for (among other things) inflation theory. ",
"On a more practical scale, the low-frequency (long wavelength) limit of an AC electrical current is just a DC electrical current. "... | [
"And what about the extremely large waves, is that limit 0K? "
] |
[
"Any Plant Genetic engineers or Plant Biologists here?"
] | [
false
] | null | [
"Hi K3RZeuz45 thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the follo... | [
"Biology"
] | [
"'Biology'"
] |
[
"In space gravity is recreated by using g-force which holds objects outwards like the gravatron at the fair, how come we cannot artificially create gravity in which the force is inwards like on earth?"
] | [
false
] | null | [
"Gravity on Earth is due to the gravitational force, which is always attractive, thus pulls you towards the center of mass of the object (in this case, \"inward\").",
"Artificial gravity, such as that of a rotating space station, is due to ",
"centrifugal forces",
", which are fictitious forces that arise whe... | [
"Gravity is proportional to mass (and, in a way, density). So, to have a gravitational effect that would be noticeable for astronauts in space, you'd need an extremely massive and dense object."
] | [
"To answer your question, no, gravity is not proportional at all to the strength of magnetic (or electric) fields; electromagnetism and gravity are two different fundamental forces.",
"Hope that helps."
] |
[
"Is there a limited amount of lithium in the universe?"
] | [
false
] | Plain and simple, I was writing an essay last night and alluded to hoe Lithium was limited in quantity in our universe, as in it cannot be "manufactured" (as from my understanding other elements may be.) I remember reading it somewhere in , but can't seem to find it now. If Li isn't the element I'm looking for, then is... | [
"Technically, EVERYTHING in the universe is finite. even hydrogen. As for hear on earth, it's not exactly rare, just kinda hard to economically extract, as it's not found in a pure form and must be extracted from other resources. ",
"Source"
] | [
"You're missing out on ",
"cosmic ray spallation",
" as a nucleosynthesis process. It's when a high-energy cosmic ray smacks into another nucleus and blows it to pieces. Think of it like fission, but it can happen to lighter nuclei because of the energy of the cosmic ray.",
"Spallation is thought to be the ... | [
"I think what you've heard about is the process called nucleosynthesis. Nucleosynthesis is the creation of new atomic nuclei from other elements. There are two primary ",
" of nucleosynthesis: fusion processes in the center of stars, and the Big Bang. ",
"During the nucleosynthesis of the Big Bang, hydrogen, he... |
[
"Why do we die physiologically?"
] | [
false
] | Not looking for answers from a philosophical or religious sense! Why do we die? Why don't cells last forever ala rocks or something? Basic question but I'm curious I guess. | [
"Our cells' DNA is in the form of linear chromosomes. Suffice to say, when a chromosome is replicated for a cell division, a small amount of the ends of each chromosome cannot get copied, and are lost. This poses a problem—as cells divide we'd just start losing DNA!",
"We have a mechanism to prevent this: \"buffe... | [
"telomeres can be lengthened through lifestyle changes (e.g. diet, exercise, not smoking, good sleep, meditation, etc.), so while telomeres are important, they're not everything.",
"Oxidative damage builds up over time, damages your DNA, impairs metabolism, and eventually you lose the war due to typically defecti... | [
"Because there is a flaw in cell's multiplying process, which leads to them losing the ability of passing their genes correctly to their \"offspring\", which causes non-fully working cells at the end.\nI don't know a lot of this subject, and I'm at work so I can't look for sources, but I believe this theory is wide... |
[
"As a female, does losing your virginity actually change your body in any way?"
] | [
true
] | I always see these strange dads obsessed with hymens being intact which made me wonder: is there actually a visible change to the body when virginity is lost? | [
"No. ",
"The common myth is that the hymen blocks the vaginal opening and is torn during the first intercourse. ",
"The reality is that the hymen is a crescent or ring of tissue, not a curtain. It can be fragile and get torn by ordinary physical activity, even something as simple as running or jumping. When the... | [
"There can be, however the hymen is not an indicator of virginity. Females can be born with a hymen that is already stretched, making them appear \"to not be a virgin.\" Or be born without a hymen at all.",
"It can be torn during play time as a child or any number of things.",
"https://www.ourbodiesourselves.or... | [
"No. It causes no physiological changes in your body overall. There is no differences after sex than compared to before other than social constructs about the experience. Society has ill treated a lot of women for a made up idea that has no physical reality."
] |
[
"What is the TNT equivalent of the explosive inside a bullet?"
] | [
false
] | null | [
"Well, as a rough estimate the kinetic energy of a normal 9mm round is about ",
"570 Joules",
". Converting 570 Joules to the explosive energy of TNT gives about the same as ",
".14 g of TNT",
". ",
"So, the bullet has the same energy as about .14 g of TNT. That's not quite the same as the energy of the e... | [
"My current load for 9mm, for example, is 3.9 grains for a 115gr bullet using IMR 700X. Depending on the powder, you can get equivalent performance from loads of 3-7 grains. You choose your powder to fill the case, while keeping your chamber pressure where you want it. This is for safety, if you use a powder that d... | [
"A rough estimate is all I needed. Thanks!"
] |
[
"Is classical mechanics complete?"
] | [
false
] | null | [
"do we have a complete set of rules that explains their behaviours and movements?",
"Yes.",
"For example in statics, do we know everything we can know about this field? Do we have all the theories and equations that adequately describe this field?",
"We know how to generate a system of equations of motion for... | [
"What do you mean \"define degrees of freedom\"?"
] | [
"Just define the things whose equations of motion you want to derive. If you have two objects colliding, those two objects (their coordinates, momenta, angular momenta, or whatever) give you your degrees of freedom."
] |
[
"An orange is a pomelo x mandarin hybrid. I have a pomelo and I have a mandarin. Can I get them to make an orange, and how?"
] | [
false
] | null | [
"it will take quite a while as you'll have to:",
"- plant the pomelo seeds, and the mandarin seeds",
"- wait until they flower",
"- cross-pollinate them",
"- the fruits that those plants make will be normal pomelos and mandarins (because the fruit grows from the ovary of the 'mother' plant) BUT the SEEDS in... | [
"Okay thanks for the answer. I guess I definitely won't have time to ",
"make grapefruit"
] | [
"Ok. How do I do it and how long will it take? Is a store bought pomelo and mandarin enough to do this experiment? I assume I'll need soil. It's winter here now."
] |
[
"In 2006 a cave was discovered that had been sealed from the world for millions of years. I want to know more!"
] | [
false
] | Does anyone know anymore about ? It's been 5 years and I can't find more online! Even more don't contain new information. | [
"There you go",
", here are some journal articles published since then.",
"Science is both costly and time consuming. I suspect they needed time to get funding and set up the lab and personnel to investigate this fascinating topic. Not to mention the cave system would require considerable more precaution and co... | [
"Thank you!"
] | [
"Geologist and part time caver here. Just so you understand the context, most caves are a part of cave systems that are vastly bigger than what is accessible by the surface. So, many cavers go exploring in caves looking for larger undiscovered rooms, many of which could be millions of years old (depending on geol... |
[
"Can someone just give me a non-doomsday summary of what we can realistically expect from climate change and how our lives will be impacted over the next 100 years in different regions?"
] | [
false
] | [deleted] | [
"These are ",
" worst case scenarios. This is when the world were to meet its most ambitious climate-change goals.",
"1.3 M",
"insects on the planets is decreasing by 2.5% per year",
"Its just not looking great. Doomsday or not, the fact things are going to change is pretty obvious. I can't believe most of ... | [
"You're basically asking for a book, luckily, it's already been written, i.e. ",
"the latest version of the 'Impacts, Adaptation, and Vulnerability' report from the IPCC",
". This provides a discussion of expected impacts by region and by type, e.g. impacts to urban areas vs rural areas, etc."
] | [
"Coastal flooding will become a steadily-increasing issue for coastal cities, and will make some islands uninhabitable. Hurricanes will destroy large areas that were relatively safe in the past.",
"Extreme weather events will become more common in general. Cycles of floods and droughts will become longer and more... |
[
"struggling with an idea of force, if some one could shed some light..."
] | [
false
] | So this puzzle was put to me by a friend. If a train is travelling towards me at x miles an hour and I shoot it front on, that bullet essentially will hit the train and reach 0 miles an hour before continuing on the trains path in the opposite direction from it's own path. What I struggle with is... For the bullet to h... | [
"I think the problem is that you are thinking of the train and the bullet as indestructible, point objects.",
"Upon impact, the bullet is going to compress and change shape, and the point of impact on the train will, also (though likely to a much lesser extent).",
"Assuming the bullet doesn't break apart and sh... | [
"Not the whole train, just the small patch of it that is stopping the bullet, and only for the tiniest fraction of a second. If the bullet fails to penetrate the front of the train, it means that patch that was momentarily slowed rebounded fast enough to catch up with the material surrounding it. If you imagine a... | [
"No part of the train slows to 0, unless part of the train is extremely deformed by the impact.",
"Assuming the bullet hits a solid, impenetrable metal part of the train, the bullet just quickly decelerates and accelerates in the other direction."
] |
[
"How could one bake a cake in zero-gravity? What would be its effects on the chemical processes?"
] | [
false
] | Discounting the difficulty of building a zero-G oven, how does gravity affect the rising of the batter, water boiling, etc? How much longer would it take? Would the cosmonauts need a spherical pan? Do speculate on any related physical processes apart from cake rising, which I just thought of as a simple example. Could ... | [
"You'd need a forced convection oven as others have discussed. I'd reduce the amount of baking soda/baking powder, because without the influence of gravity, a little bit of leavening agent will go a long way. ",
" Most if not all spacecraft are operated at 1 atm. Other than that I'd have something to hold the p... | [
"So, let us assume a spherical cake in zero g... Seriously, you could place a ball of batter in an oven, with fans arranged around it such that it is kept in roughly the middle, with enough air flow to prevent hot and cold spots. "
] | [
"It doesn't have to be a pan, but you do have to have something hold it in place, the fan from the convection oven will blow the cake around if not."
] |
[
"It is believed that the body of an astronaut will drastically change due to Mar's weaker gravity. Anyone know any specific changes?"
] | [
false
] | The first human settlement is said to be in 2025, where the first trip to Mars will take place. I was just wondering if anyone knew exact changes that would happen to the body of an astronaut on Mars. | [
"They will all quickly start losing bone density and get osteoporosis. Their muscles will also start to atrophy because of the lower demands put upon them.These are already serious issues with astronauts in space for any length of time. They've been studying this for a long time and trying to find out ways of avoid... | [
"exact changes that would happen to the body of an astronaut on Mars.",
"Unfortunately we don't know exactly. We don't have any empirical evidence with reduced gravity, so we can only extrapolate from what happens in space stations in zero g.",
"The other comment has correctly described the issues of bone mass ... | [
"Space sounds difficult but what about once they arrive? Assuming they can do some kind of exercise and radiation shielding (e.g., under rock cliffs) would astronauts stand a better chance at managing bone density loss and other ill effects?"
] |
[
"What do we know about possibly unknown wavelengths or not yet detectable forms of perception?"
] | [
false
] | [deleted] | [
"The question was about wavelengths, not elements. His point was that if we could predict \"gaps\" in the periodic table (while it was still being developed, obviously) using periodic trends, then could we also determine that types of waves with some wavelength exist without having observed them?"
] | [
"There aren't really \"gaps\" except in the 100+ atomic number range.",
"The periodic table is sorted by number of protons. You can't have half a proton. We have discovered elements every naturally occuring element. There aren't gaps remaining except in the manmade elements with over a hundred and ten protons tha... | [
"Thank you, exactly.",
"But the wavelenghts are just an example, it could be anything that we are (hypothetically) able to detect or will be able.",
"I'm actually looking for some kind of educated guess/scientific speculation."
] |
[
"Do octopuses show reduced cognitive abilities/lower intelligence after losing one or more of its tentacles?"
] | [
false
] | So I know that octopuses have an incredible neurological system in place with a main brain and one smaller one in each tentacle, plus an extensive nervous system. When an octopus gets attacked and loses an arm/tentacle it will eventually regrow, but: Will the mental capabilities/intelligence also reduce for that time? ... | [
"I am pretty sure that is not the case. \"Smaller brains\" is just a term to facilitate human understanding. Ocotopuses dont have something like 9 different thought processes or anything of the sort. These \"brains\" are larger assimilations of neurons, not distinct structures, like this wording suggests. The purpo... | [
"My big brain: this",
"My arm brains: this this this this this this this this"
] | [
"since every arm can perform every task.",
"I'm quite certain I'd read they have preferential \"leg\" and \"arm\" tentacles, but I don't suppose the \"legs\" couldn't act as \"arms\" if necessary."
] |
[
"Which is better? A lot of antibiotics all at once or smaller doses over a longer term?"
] | [
false
] | Reading up on antibiotic use, particularly why you need to finish your prescribed regimen despite alleviation of symptoms, got me wondering: If you're given - as an example - instructions to take 2 pills a day for 4 days, why would it not be more effective to take 4 of them a day for two days or even the whole bottle a... | [
"Antibiotics (AB) don't generally directly kill bacteria, some inhibit enzymes in their wall (B-lactams), some attack ribosomes (macrolides) etc which causes them to eventually fail at life. Im not sure if the AB you are prescribed depends on whether they are aerobic or anaerobic, but it does depend on whether they... | [
"Your assertion that antibiotics don't generally directly kill bacteria is incorrect, as are your examples that you give.",
"Antibiotics have two main sub-classes, these two classes are bactericidal and bacteriostatic.",
"Antibiotics like beta-lactams are bactericidal and will kill a cell directly where as some... | [
"yeah good point, thanks for clarifying"
] |
[
"What is the significance of the orientation and dip of rocks in a sedimentary layer?"
] | [
false
] | null | [
"If the dip (angle of beds measured with respect to horizontal) is not horizontal or nearly horizontal, then it means the bed has been titled from its original orientation. Not sure if this answers your question, but if it doesn't, you'll need to provide some more context."
] | [
"It sounds like you're describing clast imbrication. Does ",
"this diagram",
" kind of fit what you're describing, where the the bed with uniform clast orientations looking like either the top or the middle panel depending on whether they are matrix or clast supported? If this is the case, as the diagram indica... | [
"Maybe I could have worded the question a little better, I'm looking into the orientation of clasts in a layer, and so far I have found one layer in-which the clasts seem to have a random orientation and another which the rocks seem to have a uniform orientation, I was wondering about the significance of this. "
] |
[
"How accurate are DNA tests in determining ancestry?"
] | [
false
] | Particularly things like 23andMe and ancestry.com. Can they really determine your ancestors' ethnicities, or is it all a scam? | [
"I'm an anthropological geneticist with a particular interest in genetic ancestry testing. I'll answer based on my experience.",
"Accuracy really depends on the algorithm used, the reference data that is available to the people running the algorithm, and whether the ancestry of the person in question is sufficien... | [
"It's of varying accuracy. Mostly it's down to how extensive the studies of different groups of people have been (in the studies the services make use of) and how well the services collect and analyze the information. Some things are easy, especially in relationship to well studied populations (like Europeans), som... | [
"Thanks for the detailed answer!",
"As a follow-up: If our reference data are modern-day populations, how does historic immigration factor into the results? In your case for example, if your descendants were to move away, their DNA test would show Irish ancestry, but would not show their more recent Australian an... |
[
"I'm 0 negative blood type. Could I give blood directly from my circulatory system to any other person's?"
] | [
false
] | [deleted] | [
"If you are witnessing an acute trauma, then no, you should not if you can help it, as there are better first-responder options, such as packed RBCs or IV saline. Being O- means that you have circulating plasma antibodies against other antigens. There are have been document cases of hemolytic reactions occurring se... | [
"Blood, broadly speaking, has 2 components: plasma and RBCs. Plasma will generally contain the platelets, coagulation factors needed to form a clot, and antibodies to foreign molecules. AB+ people are great for donating plasma because their own RBCs have are all decked out on antigens, and their ",
" B-cells won'... | [
"So if I understand it correctly:",
"Since an individual cannot be both AB+ and O-, OPs suggested course of action is very risky compared to simple saline transfusion. (?)"
] |
[
"Why is Fe the last element produced through fusion in a star; why does Fusion not continue beyond that point?"
] | [
false
] | I am particularly interested in why "gravity wins out," over the force produced by the fusion reaction. | [
"Unlike with other elements, fusion into elements past iron isn't energetically favorable, so it won't happen to any appreciable degree in a stable star."
] | [
"when you combine several nucleons into nucleus of an atom, you will find out that the weight of the atom nucleus is actually little less than the weight of the nucleons alone. the missing mass is hidden in so called binding energy (energy E=mc",
" missing mass) of the strong nuclear force. the is strong nuclear ... | [
"To add: ",
"This figure",
" shows the binding energy for various atomic nuclei. Nuclear reactions that produce nuclei higher up on this plot are energetically possible, whereas moving down requires energy be input to the reaction to occur. Fusing to produce elements heavier than Fe-56 doesn't produce energy ... |
[
"At what temperature can my body not maintain equilibrium when naked"
] | [
false
] | So if its a little chilly in my room I can still be naked, feeling a bit cold but otherwise ok. My skin may be colder to the touch than normal, but I'm fine, im not going to go hypothermic. So if i can happily sit naked at say 18 degrees, at what external ambient temperature will my body be unable to maintain equilibri... | [
"There is no set temperature.",
"The lower the temperature the more quickly you will die.",
"You can survive 5 seconds at negative 30 (c) naked. But you will die in less than an hour.",
"You will probably die in a day or 4 at 0 (c) naked depending of your body mass and fat reserves ability to insulate and pr... | [
"The heat output is incredibly variable. Your body is good at producing and conserving heat when in times of need, and it is good at dissipating it to the evironment when in need of cooling.",
"The amount of heat your body can produce or dissipate is different from person to person. In general, someone who is i... | [
"i geuss im wondering if someone has worked out the heat output from a human being, and the rate of heat production of a human, and done some co-efficient of cooling to dsicern the equilibrium point"
] |
[
"Cannabanoids' content and plateau in Cannabis"
] | [
false
] | null | [
"Interesting question that I cannot answer but I wanted to say to you and everyone: please make sure to ignore the replies of people who are going to try to turn this into some moral/political debate. "
] | [
"Indeed, this is strictly for scientific knowledge."
] | [
"Anything not ",
" on-topic in this thread is subject to deletion (as always, but especially in threads like this)."
] |
[
"Is it possible for a gas to be heavier than a liquid?"
] | [
false
] | null | [
"At very high pressures, like those on gas giants like Jupiter and Saturn, there is not a sharp distinction between liquid and gas states like there is on Earth. At the surface of the liquid phase, gases are so highly-compressed that they're only slightly less dense than the liquid phase itself. However, at those... | [
"I don't think so - at least not at standard conditions. A quick Google search leads me to believe that tungsten hexafluoride is the densest gas we know of. (If not, it's close - at least within an order of magnitude of the densest gas I'm sure.) It's density is only ~12 g/L. For comparison, water's density is 1,00... | [
"It's a solid, but really it's more of a matrix with gas trapped in it. Kind of like a really rigid marshmallow."
] |
[
"What Makes Something \"Funny\"?"
] | [
false
] | This concept may be hard to understand but when a comedian tells a joke or something that makes me laugh, what makes my brain register it as "funny"? When I think about this, I come up with this scenario. If I were to say a funny statement and a statement, why is it that the first one is funny and the second one is not... | [
"I've actually done a bit (just a bit, though, no expert) of research in to this because I was really curious. Like I said, I'm no expert, but this is the really basic stuff till someone better versed comes along. Most laughter occurs in one of two circumstances.",
"Your brain is surprised because something unexp... | [
"How about observational comedy? Why do we find the truth funny? Have any insight on this?",
"Good question btw OP, I love when people think of good questions for the people in this sub reddit."
] | [
"If I had to guess, I'd put it somewhere around the \"feeling superior\", as most of the time observational humor points out the flaws in someone else or in a system."
] |
[
"Why is rear locking differential better than four wheel drive?"
] | [
false
] | Is it better in all situations (off road vs snow vs ice vs etc.)? | [
"A differential allows for the driving wheels to spin at different rotations per minute therefore allowing a car to turn corners. This is because the inside wheel in a turn has less distance to cover than the oudside wheel on the vehicle in the same turn. ",
"Think plastic coffe cup on it's side. It will roll in ... | [
"Where did you hear this info? Locking differentials are almost always paired with four wheel drive. It certainly does get more traction in addition to 4x4, but a locking differential without 4x4 wouldn't be as effective. With four wheel drive you have power going to every wheel unless you lose traction in one w... | [
"Locking differentials are best suited for off-road or low traction environments. With a locked differential both drive wheels will turn at the same speed making turning more difficult if you have full traction. This will give more wear and tear on your tires on asphalt and your tires will chirp as you go around a... |
[
"What triggered cosmic inflation?"
] | [
false
] | As far as I know the cause of inflation is debated. Some say it is caused by a phase transition (which I didn't fully understand) which happened when the strong nuclear force separated from the electroweak force. But I also heard that that theory is old and more or less abandoned now. What is the current most accepted ... | [
"Inflation is driven by a scalar field called the inflaton. (A scalar field being a field that is just a number, at any point in space and instant in time). The inflaton lies initially in an excited state which gives a large constant energy density in space. This triggers a violent exponential expansion exactly lik... | [
"Where the inflaton comes from or what it is is a separate, but interesting question. There's many ideas about that too.",
"can you outline some of those ideas or give some good articles on that?"
] | [
"One idea I recently saw was that if you assume the speed of light C was almost 0 at the \"beginning\" of inflation, the growing speed of light (information being transfered faster) would correlate to a stretching of all spatial dimensions, similar to inflation.",
"Just a theory tho, no proof behind it from what ... |
[
"How does a landlocked state develop CAT 3 winds and why is there no name for this type of storm?"
] | [
false
] | Utah just had winds over 100 mph the last few days and it's never happened here previously. | [
"There actually ",
" a name for this type of storm: a ",
"downslope windstorm",
", where strong winds descend down a mountain slope or other terrain feature. While these storms are uncommon in central Utah (especially events of this severity), they are actually quite common in very specific areas, to the poin... | [
"I truly appreciate this answer. I could not locate anything to explain this event in this depth. I'm going to share this answer for those who also have this question and keep all the sourcing."
] | [
"never happened here previously. ",
"Actually it has happened here every few years or so. ",
"The last big one was in 2011",
", but while like tornadoes, they don't happen frequently but every now and then. ",
"There's even a National Weather Service case study showing how often they occur",
". And unl... |
[
"If diamonds are made of just carbon, is it possible to get a diamond to catch fire?"
] | [
false
] | [deleted] | [
"The ignition point of diamond is between 850 and 1000 degrees Celsius in air. A propane torch can reach temperatures of 2000 degrees C.",
"Here's",
" someone heating a diamond up and then tossing it in liquid oxygen to set it aflame.",
"Antoine Lavoisier",
", thought of by some as the father of modern chem... | [
"Since it takes more energy to create a diamond than you can get out of it and it takes a lot of energy for it to release its energy, probably not."
] | [
"Yup, it'll burn- It'll take a lot of heat though because it's so stable! ",
"Here's",
" a link to a PopSci article where they have a video of them burning a diamond ring with a torch. "
] |
[
"Is it better to have a healthy cardiovascular system/body in general when bleeding out?"
] | [
false
] | I was thinking, someone who is older or with a weaker heart etc should bleed out slower, which seems to make me think they would survive for longer. Is this true? Or is there something which a healthier body does which can counteract (maybe the effects of hypovolemic shock aren't as bad or something) the effects of exs... | [
"Your post title has it right. People who are young and healthy have a better chance of recovery after losing a significant amount of blood. The speed of blood loss wouldn't be altered enough to make any difference; instead, what's important is the body's ability to cope with the loss.",
"Up to a certain point, t... | [
"No. That's not quite what I'm saying. ",
"A young, healthy person's heart will not be beating faster to begin with. It will be going slower, because he has more red blood cells and more efficient lungs and so doesn't need as much velocity to keep everything oxygenated. So if there's any difference in the speed o... | [
"The speed of blood loss wouldn't be altered enough to make any difference; instead, what's important is the body's ability to cope with the loss.\nUp to a certain point, the body can compensate for blood loss by increasing heart rate and respirations. A healthy heart has a lot of \"cardiac reserve,\" and can tripl... |
[
"Is there a physical limit to the number of receivers that can receive a transmitted signal?"
] | [
false
] | Or to ask another way, does a receiver absorbing the energy of an EM wave affect the power of the transmission in any way? | [
"This is almost a duplicate of:",
"https://www.reddit.com/r/askscience/comments/q2dh3/does_picking_up_a_radio_signal_with_a_antenna/",
"This is like asking if there’s a limit to the number of eyes that can see a lightbulb. The answer is yes, because each pair of eyeballs blocks some of the light, but they don’... | [
"Surprisingly with WiFi this limit is fairly small for most consumer routers. Generallyy I think less than 60 for most Wifi router / access points. This may sound like a lot but in a small office setting or a medium sized home with home automation using WiFi I can see this number reached fairly easily."
] | [
"At radio frequencies, the energy in a single photon is extremely small. By the time you have enough energy to receive a viable signal, you have so many photons that they aren't worth counting, which is why engineers rarely think about photons when dealing with radio waves.",
"Edit: quick calculation. One photo... |
[
"What is the theoretical height-limit of a building using modern materials and engineering methods?"
] | [
false
] | null | [
"Cost benefit is usually maximized just around ~65 floors. Building taller is often about prestige.",
"Source: National Post, Monday, July 23 2001, pp. A 1-2 ",
" McGrawhill Ryerson Corporate Finance 4th Edition, Ross et al, page 193."
] | [
"Cost benefit is usually maximized just around ~65 floors. Building taller is often about prestige.",
"Source: National Post, Monday, July 23 2001, pp. A 1-2 ",
" McGrawhill Ryerson Corporate Finance 4th Edition, Ross et al, page 193."
] | [
"Modern materials come into play if you want to build a roughly cylindrical structure like a skyscraper. But you can build a very, very tall building with primitive materials if you use a lot of them. Imagine a tapering cone, where the radius decreases rapidly with height so that the amount of material at each leve... |
[
"How old is the inner core of the Earth?"
] | [
false
] | I am trying to find out when the inner core was formed but every source I look at ranges too much from 50 million years after the earth formed to even 500 million years ago which over a 4.5 billion span is a lot. I understand it formed from the heavy iron and nickel materials sinking to the centre and solidifying from ... | [
"This ignores a pretty extensive body of literature addressing this very question with a variety of isotopic techniques, mostly U-Pb and Hf-W systematics. These exploit the different chemical affinities of the parent vs child isotopes (i.e. the parent isotopes tend to end up in the silicate part where as the daught... | [
"Yes, you're right. ",
"My point at the end about paleomag not being relevant to this is still valid as even at the high end of estimates mentioned here for inner core formation, we do not have paleomag going back any where near that far (reliable records of normals and reversals go back to the middle of the Pale... | [
"As far as I was aware there was no clear time for when it formed as we would need a way to probe that deep into the Earth while also being able to look at the ancient history. ",
" ",
"One way (maybe the only?) is the field of ",
"palaeomagnetism",
". However, we do not really understand the role in which ... |
[
"What is the evidence that space is distinct from matter/energy?"
] | [
false
] | When we say that matter 'warps' spacetime, how is this different than saying matter is a local compression (densification) of spacetime? In other words, could matter simply be 'folded' space, with different aspects of matter/energy being differently 'folded' into stable configurations, and 'space' just being the unfold... | [
"When we say that matter 'warps' spacetime",
"Total nitpick: The word is ",
" I say this because ",
" is a very specific concept in differential geometry, and that concept is really what we're talking about here. It's not just any old arbitrary transformation, but rather a very specific kind of transformation... | [
"Thanks for the reply. Wouldn't the geometry simply be a property of energy/matter, without any requirement for an independent space? In other words, who needs space anyway?"
] | [
"Space is what separates events which occur simultaneously. Yes, we \"need\" space in our theories, because space exists."
] |
[
"What kind of impact, if any, would Betelgeuse going supernova have on Earth's climate?"
] | [
false
] | Hey AskScience! I was wondering if something as distant as Betelgeuse could influence the atmosphere enough for us to feel it or see it? I seem to remember that it would cause a long period of near daylight for us, but would the temperature of the planet change? | [
"As far as I can tell, the overall effect would be essentially negligible.",
"A star like Betelgeuse should explode as a type II supernova at the end of its life. The brightness of these vary some, but a reasonable estimate for the absolute magnitude is somewhere around -17. Betelgeuse is perhaps 200 parsecs from... | [
"As Mu0nNeutrino says, there wouldn't be a huge effect in terms of brightness/visible flux.",
"However, one thing in the back of my mind might be the increase of energetic particles mimicking the effect of cosmic rays. Two main angles come to mind - firstly, those might be a serious risk to anyone in space at the... | [
"Cosmic rays nucleating clouds? Sounds interesting, I haven't heard of this before. Seems hard to prove definitively."
] |
[
"Is the temperature an object can reach limited to the temperature of the heat applied to it?"
] | [
false
] | Not sure I worded that the best so here's an example. Say I have a piece of metal and I'm applying a 500 degree flame to it. Will that metal only ever reach a maximum of 500 degrees, or does the thermal energy continue to build past that? | [
"That isn't right. Heat is not a measurement of the total energy stored in a body. Heat is energy being transferred from hot to cold."
] | [
"Yes it is limited by the temperature difference. Heat will flow where there is a change in temperature ONLY. So not difference in temp, no heat flow.\nAlso temperature =/= heat. Heat is a form of energy that can lead to a change in temperature. "
] | [
"Correct. You can add heat to a system and actually have its temperature stay the same or even decrease (provided that the system is doing work equal to or exceeding the heat added)."
] |
[
"I saw what looked like a rainbow halo around the sun the other day, what did I really see happening?"
] | [
false
] | So I was at the beach in Florida and i looked up to notice a halo of light circling the sun. The halo looked somewhat rainbowish in color, but it was hard to see since it was right next to the sun. Sorry if this is incorrect format or has been answered before, I'm new here. Edit: I saw the floating rainbow pictures and... | [
"It's a function of the interaction of clouds, which are filled with water droplets, and sunlight. The same way you get a regular rainbow by sunlight shining through water droplets in the air, you can get a circular halo rainbow around the sun. The size, shape, and location of the clouds determine whether you see a... | [
"Oh interesting, thanks a lot."
] | [
"This website",
" has loads of information about all kinds of optical atmospheric phenomena. I would guess one of the ice halos."
] |
[
"Is there a difference between natural sleep and sleep via medication?"
] | [
false
] | Does your body heal up the same way? What about cognitive ability? Is there actually a difference from when you fall asleep naturally compared to taking a sleeping pill? Or even getting black out drunk? | [
"There are several ",
"phases",
" of sleep. Depending on which medication you take, you will influence these phases differently. For example, certain benzodiazepines such as flumazenil will inhibit stage 3/4/REM sleep while other related medications such as zolpidem will spare these phases, to a degree. ",
"F... | [
"What about something like Valerian root ?"
] | [
"What about something like Valerian root ?"
] |
[
"After primates, what are humans closests relatives?"
] | [
false
] | After you break everything down and start to leave the taxonomy of humans, what would be the closest reletive outside of primates? | [
"The sister order to Primates is ",
"Scandentia",
" which are tree shrews. "
] | [
"Based on results from different studies, probably either tree shrews (Scandentia) or 'flying lemurs' (Dermoptera). See discussion ",
"here",
". Both hypotheses are supported by some data (although both can't be true), and open to corroboration or rejection by additional evidence.\nIt should be noted that all... | [
"Using your same logic we ARE mammals."
] |
[
"If someone loses their memory in an accident, how do they retain their linguistic skills?"
] | [
false
] | null | [
"This is a common question that should be directed to Hollywood. There are actually very little evidence for the type of \"complete amnesia\" that is shown in movies and TV shows. The more common is the loss of memory around the time of the accident, but usually restricted to a few seconds or maybe minutes. But I g... | [
"This is pretty spot on. We also know of certain areas that are very critical for linguistic ability (Broca's/Wernicke's are the most well-known), and although they exist in the cortex, the cortex is thought to diffusely store memories there somehow. We don't know where memories are truly \"stored\" in the cortex, ... | [
"Yes, the total-memory-loss-from-a-bump-on-the-head that you seen in movies is pretty much totally inaccurate. I'm not quite prepared to say a total loss of one's personal memory NEVER happens because this is not exactly my area of expertise, but I've certainly never read about it in the scientific literature.",
... |
[
"Why can't our eyes focus on things that are close to them?"
] | [
false
] | [deleted] | [
"This is incorrect, your eyeball isn't stretching (although it might a little bit) enough to seriously affect the focus, what is happening when you focus is the Cilliary Muscles which surround the lens in your eye are contracting or relaxing in order to change the shape of your lens, the reason we cannot focus on a... | [
"This is incorrect, your eyeball isn't stretching (although it might a little bit) enough to seriously affect the focus, what is happening when you focus is the Cilliary Muscles which surround the lens in your eye are contracting or relaxing in order to change the shape of your lens, the reason we cannot focus on a... | [
"Not at all, a lot of the focusing is actually done by the cornea; the very front of your eyeball, I believe the iris is there simply to surround the pupil and look pretty "
] |
[
"A book I'm reading mentions the use of silver nitrate to help people quit smoking in the 1890s. How on Earth did that work?"
] | [
false
] | Here's the passage. It's from by Allan Brandt: As cigarette use increased in the first decades of the twentieth century, antitobacco activists and their medical supporters eagerly devised "cures" for individuals who had succumbed to the habit. In Los Angeles, the city sponsored a popular "anti-cigaret clinic" that drew... | [
"It's a very weak solution (something like 0.5%) not like chewing up a caustic silver nitrate stick and makes the cigarette taste bad. ",
"In the late 1800s the same sort of weak solution was used as eye drops for infants to prevent gonorrhoea infection. Once modern antibiotics came about this stopped. "
] | [
"Silver nitrate, as you've mentioned, is a chemical cauterizing agent. It absolutely can be used orally, actually. I use it to cauterize my oral ulcers. Hurts like a bitch but it's effective.",
"With regards to smoking cessation, I found ",
"this patent",
" from 1989 for a silver nitrate mouthwash that claims... | [
"If you don't get an answer here you could also try ",
"/r/askhistorians",
" or ",
"/r/historyofmedicine"
] |
[
"Military and police dogs are, inevitably, around weapons. We humans wear hearing protection, because many larger-caliber small arms can be quite loud. Can being close to gunfire cause long-term damage to dogs’ hearing?"
] | [
false
] | Additionally, is it painful for them, and are there any methods of protecting dogs’ ears? | [
"You can easily find many examples of military and police dogs wearing ear protection: ",
"http://www.safeandsoundpets.com/page/page/5018957.htm",
"Usually this is to protect them from the noise of boat or helicopter engines, but there are also examples of dogs wearing ear protection while their handler is shoo... | [
"Police and Military dogs are not especially exposed to loud noises. It happens to them, but is a relatively rare event. The dogs for which hearing damage is a real problem are hunting dogs, and especially gundogs (spaniels and retrievers). A gundog may be exposed to the sound of thousands of shots each day, severa... | [
"Exactly what I was looking for. What inspired me to ask the question was seeing a video of a dog hop onto his owner’s back while the owner shot at targets. It was cool, but I’d hoped that dog’s ears didn’t get too damaged (looks like they do unfortunately)"
] |
[
"Does extreme-depth oceanic pressure have an increased viscosity-like effect on anything passing through it?"
] | [
false
] | After the discovery of the new species of snailfish in the Mariana Trench, I began to wonder if deep sea creatures actually have to exert more energy to pass through water at such high pressures. Does extreme pressure have the effect of higher viscosity, or does it have the same properties as water under normal condit... | [
"Viscosity is most strongly a function of temperature for most fluids at \"normal\" conditions, including water. Pressure itself generally only has an indirect effect on viscosity by its effect on temperature via some equation of state.",
"Cold liquids (Marianas trench is going to be slightly above, freezing, say... | [
"There's two basic types of drag, \"pressure\" or \"invisicid\" or \"form drag\", and \"viscous drag\". (For pedants, I consider wave drag to be under the umbrella of pressure drag).",
"Viscous drag is a frictional force, it acts tangential to a surface, and it's proportional to viscosity - analogous to the coeff... | [
"Can you say more about \"inviscid form drag\"? Would that be a problem for wildlife here?"
] |
[
"How deep into the Earth have we gotten? Is there anyone trying to go deeper?"
] | [
false
] | [deleted] | [
"The ",
"Kola borehole",
" is the deepest hole so far - 12 km deep.",
"There are plans to ",
"drill into the mantle",
" - but under the ocean where the crust is much thinner.",
"Also, how do we know that the earth is made up of a Crust, Mantle, Outer Core and an Inner Core if we haven't gotten that deep... | [
"A large ocean depth doesn't necessarily mean the crust is thinner there. And it makes drilling much more difficult."
] | [
"Isnt the ocean just 11~km deep at its deepest parts digging from there would mean less work to go further than we have before but wouldnt the crust still be to hot to dig further? "
] |
[
"Tied by the arms and feet and pulled apart, what part of the human body gives out first?"
] | [
false
] | I just saw a movie that opens with this scenario: A guy has his hands chained to one car, and his feet chained to another. The cars drive in opposite directions. The guy is split in two mid-torso. It seems much more likely to me that either his arms or legs would be torn off. What would happen in reality? | [
"Strictly anatomically speaking, it would make sense that the hip would be more difficult to \"tear off\" purely on the basis of more muscle and tendon mass surrounding the joint. The difference being comparable to tearing off a turkey wing from a raw bird compared to trying to remove the leg. (Feel free to try thi... | [
"you are correcting a question asked by a person other than yourself, he clearly said chained arms and legs, the origin of the question does not matter."
] | [
"because spoilers and some of us haven't seen the film... and it's not really relevant to the question. The question as posted is fine; there's no reason to spoil a part of a movie trying to correct him :P"
] |
[
"how is it possible for infinite regions to have finite areas?"
] | [
false
] | if you graph the function one over x squared (1/x ) you can see that there is a vertical asymptote along the y axis and a horizontal asymptote along the x axis. So basically, as your x values approach zero your y values approach infinity and as your x values approach infinity your y values approach zero. In other words... | [
"The same way that any infinite sum can a finite value: the value of the sum is a limit. This means that as more terms are added to a finite sum, the difference between the finite sum and the exact value of the infinite sum can be made arbitrarily small. Same way that 0.999... = 1. "
] | [
"Imagine a square with side length 1. Its area is of course 1. Now imagine a rectangle with side lengths 1/2 and 2. The area of that rectangle is also 1. A rectangle with side-lengths 1/3 and 3 also has an area of 1. In fact, for any natural number n, a rectangle with side lengths 1/n and n has an area of one. One ... | [
"Say I have a square of paper that has an area of 0.9\" squared. I then add a piece that has an area of 0.09\" squared, by cutting a ribbon of 1/10th of the size of my first piece. And one that is ten times smaller again. And so on, and so on. I lay all these pieces end to end.",
"Hopefully you'd agree with me th... |
[
"Do frequent, small earthquakes hint towards a larger one in the future?"
] | [
false
] | I live in Los Angeles and within this month there have been 4 small earth quakes in the Southern California area (you can google it). Does this forewarn us of a much larger one to come? Or is it actually better to have smaller, frequent ones like there are now? please break this down for me. | [
"As a geophysicist, I have to say that this is not true. We know that large quakes set off lots of small quakes, but we have no real knowledge about what role small quakes play in triggering large earthquakes. While it's true that small quakes may release building stress in the plates, it's also true that small qu... | [
"Well here's the thing, Not all faults are along major plate boundaries. Small earthquakes could be caused by shallow nearby faults."
] | [
"Well earthquakes are a result of sudden moves at the ",
"continental plates",
".\nThis is also why at the borders there are more earthquakes than at the plates center.\nThe bigger the move the more energy is given off in form of shockwaves.",
"So if you want, you want to have a lot of tiny moves that don't r... |
[
"In Space (ISS for example), do items floating within an enclosed structure contribute to that structure's mass?"
] | [
false
] | This is probably a stupid question and I'm just over-thinking it, but I saw a basic experiment of how the "floating" / magnetic household items still retain the weight of their "floating" object because gravity is still pulling on the item which exerts that weight onto the magnetic field which in turn forces the base t... | [
"Really this all depends on your perspective. Also i will make a quick but important distinction between mass and weight.",
"mass is a measure of how much matter is present in an object. basically how many protons and neutrons (and electrons) are present. Weight is the force of gravity on an object. related to th... | [
"Every particle has its own mass; it doesn’t “contribute” to something else’s mass. The mass is collective. Each particle deforms space-time in its vicinity. A lot of particles in close proximity contribute to the local curvature of space-time \n(edited space->space-time)"
] | [
"Not really. Although in common parlance, kilograms may be used as a weight measurement unit, in science and engineering one would likely measure something’s weight in Newtons. Weight is a force, and mass is more like a measurement of inertia. They are related but they are different properties and so you really... |
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