title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Do heavier objects actually fall a TINY bit faster?"
] | [
false
] | If F=G(m1*m2)/r then the force between the earth an object will be greater the more massive the object. My interpretation of this is that the will accelerate towards the object faster than it would towards a less massive object, resulting in the heavier object falling quicker. Am I missing something or is the differenc... | [
"You are correct, heavier things will accelerate the earth more than light things. The acceleration of earth is equal to G*m2/r",
" For a 1000 kg mass on the earth's surface (~6 x 10",
" m), this translates into an acceleration of about 2 x 10",
" meters per second",
" .",
"The very best accelerometers ca... | [
"Yes, but you have to remember that since F=ma, a=F/m=(GMm))(r²m)=(GM)/r², the mass of the accelerated object is irrelevant; only the ",
" acceleration would be higher because the earth would accelerate towards the object at (Gm)/r², so the relative acceleration would be (G(M+m))/r²"
] | [
"However, in terms of the question posed, if you drop the two objects together next to each other then as the Earth gets uniformly accelerated towards them (can assume a barycenter of two smaller masses) they would fall at the same rate or at least an even smaller difference"
] |
[
"How could the universe really be infinite?"
] | [
false
] | Wouldn't the fact that the universe isn't still the same density and temperature suggest that we didn't exactly start with energy? Maybe I'm mistaken and the universe started from a point of finite energy but infinite If this is the case then how could we ever say that the universe is infinitely large? Wouldn't there b... | [
"Yes, if it's infinite in size, then it has infinite total energy. We don't know just how close the universe got to infinite energy density in the early universe. Our physics breaks down before we can get back to those early times. It seems to approach an arbitrarily large energy density, but it's unknown whether t... | [
"and the big bang originated from one point",
"It didn't. It happened everywhere. The entire universe began expanding, \"creating\" space within itself. If the universe was ever a single point, that single point turned into a thing with 3 dimensions of space and one of time. But more likely it was just a volume w... | [
"Wait, can you elaborate on the last part? Do you mean space was always infinite and the big bang started at some arbitrary point in the middle of it? I thought that \"space\" was the stuff that expanded from the big bang, which had nothing outside of it."
] |
[
"Is a black hole really a hole? Or more of a ball?"
] | [
false
] | As I understand it, black holes are just collections of matter so incredibly dense that the force of gravity is greater than the speed of light. So, why is there this idea of a hole? As if it somewhere? I imagine it more as a big ball of matter pulling everything around it inwards, am I wrong? | [
"The main reason why it's called a \"hole\" is that once something falls in, it never comes out again. It is, to all intents and purposes, a hole in the universe. In fact, it's more specifically a 4-dimensional hole, which appears as a ",
" in 3-dimensional space. The same goes with hypothetical wormholes. Th... | [
"Time is indeed the fourth dimension, but the catch is that time is actually equivalent to space. In relativity, there are four dimensions, and only one velocity: ",
", or the speed of light in a vacuum. In other words, ",
", including you, me, and the photons entering your eyes right now, is moving at exactl... | [
"And you're right, it ",
" a ball, in three-dimensions. But in ",
" dimensions, it's a hole, or a place where you can travel a potentially infinite distance in an ",
" dimension, a dimension that exists ",
" to the three dimensions that we are familiar with. Here, let ",
"my favorite person",
" explai... |
[
"[Biology] How do antibodies work and why has there never been a case of bacterial resistance to such antibodies?"
] | [
false
] | null | [
"Antibodies, also called Immunoglobulins, are proteins that are secreted in response to an antigen, which is most commonly a protein of the pathogen, but can also be against a toxin.\nAfter an immune cell of the Innate Immune System (the first responders), a Macrophage for example, engulfs and destroys the invader,... | [
"Antibodies help kill microbial pathogens through several mechanisms, which are outlined well ",
"here",
". Through the process called neutralization, antibodies can physically block outside components of pathogens. For example, antibodies against outer viral proteins can prevent the virus from binding to and e... | [
"Great answer, said everything I might have and more, much better than I could have."
] |
[
"Do animals that develop thicker coats for winter depend on the temperature for it to occur?"
] | [
false
] | For example, I live in the northern hemisphere and my cat grows a thick coat during winter. If I were to move to Australia, how would my cat be affected? What if I had an indoor cat where the temperature remained constant? | [
"Not necessarily. If you have an indoor cat in a perfectly climate controlled house, you would still expect it's coat to change despite the temperature of the house not changing. Most animals that experience this change (among many other physical processes!) do it via light cues. Less day length results inane anima... | [
"On a related note, seasonal changes among organisms (including plants like trees who leave their foliage in the winter) are generally most commonly a function of the more periodical and reliable day length, not the greatly varying temperature."
] | [
"On a related note, seasonal changes among organisms (including plants like trees who leave their foliage in the winter) are generally most commonly a function of the more periodical and reliable day length, not the greatly varying temperature."
] |
[
"A hotel in Hong Kong will be serving wine salvaged from the Titanic wreck. Many questions present themselves."
] | [
false
] | is serving a bottle of 1907 Heidsieck & Co. Monopole Gout Americain wine, salvaged from the wreck of the Titanic. Aside from this being rather macabre, many questions present themselves: How can a bottle of liquid survive at that depth? Assuming a completely full, spherical glass bottle, would there be a pressure diffe... | [
"1) Because water, like many liquids, is very incompressible. Meaning its density changes very little with pressure. At the pressures at the wreck of the titanic, you're only talking about a few percent increase in density (and thus decrease in volume). So even if the pressure difference was maintained (see below),... | [
"Could the cork really hold up that long? It's difficult to imagine the contents being completely undisturbed."
] | [
"I'm very curious about the provenance of that champagne. I didn't think RMST had sold any of the artifacts to private interests. There ",
" some of that champagne salvaged from the Baltic, found at a much shallower depth. I wonder if they actually have the Baltic shipwreck champagne instead of Titanic champag... |
[
"How can 2D CMB radiation images tell us about the structure of our 3D universe?"
] | [
false
] | [deleted] | [
"The data you see in most CMB pictures already has radiation from stars and dust clouds removed (the raw data looks more like ",
"this",
", processed data looks like ",
"this",
"). Techniques for doing that are... a lot of work, but pretty good overall.",
"The we can get data from the structure of the 3D ... | [
"There are a few ways.",
"First, it's a snapshot of the Universe at a particular time, and as with any snapshot, we can use it to learn about the conditions at that time. That time, by the way, was about 380,000 years after the Big Bang, when protons and electrons combined to form neutral atoms, and light was fre... | [
"I laugh on the inside when I hear a physicist talk about how the CMB is isotropic. A general audience doesn't know what isotropy is!",
"ie:\n",
"https://www.youtube.com/watch?v=uGbWIVzjays"
] |
[
"What would the void between galaxies look like?"
] | [
false
] | I am a writer and have an interesting idea for a story I would like to pursue. However, I found myself asking a question while developing the idea farther. In the story a man finds himself lost in the void of space while traveling from one galaxy to another. My question is simple; what would the man see? Would the ... | [
"It would indeed be utterly blackness for the most part, but you'll be able to make out a few smears of light from nearby galaxies (if they're within a few million light years). On a dark night on earth, you can make out the smudge of the Andromeda galaxy 2.5 million light years away with the naked eye."
] | [
"True, but I was thinking that the start and end of the journey would be quite stunning."
] | [
"God damn, that is so fucking creepy."
] |
[
"Something that has always bothered me about crepuscular rays... The light source appears to be a couple ten's of thousands of feet above the clouds when it is obviously the sun. Is the light bouncing off the upper atmosphere or something?"
] | [
false
] | With photos like this it always appears to me that the light source is very close as if sitting right behind the clouds. Why does it appear to be so close when the earth is so far away from the sun. Shouldn't the light theoretically hit the earth at pretty much a 90 degree angle? Or is this just because it isn't high n... | [
"It's exactly the same thing that's happening in ",
"this image",
". The crepuscular rays are parallel, just like the rails. In this example, if you were to lower your viewpoint closer to the ground, the apparent angle between the images of the rails would approach 180 degrees.",
"As an aside: that \"pale blu... | [
"The light rays are not coming straight down, because the Sun is not above clouds. If you were standing at the point where you now think that the Sun is at 90 degree angle, you would see the exactly the same situation as in the point where you are standing now. The Sun would still be 30 degrees or something like t... | [
"The idea of the stick losing length makes sense to me. But in my mind i still don't understand how two seperate crepuscular rays could ever create a more than 90 degree angle.",
"Say conditions provided me a chance to observe a set of crepuscular rays for 5 or 6 hours. I wouldn't be able to watch them move as ti... |
[
"How does darkness affect us?"
] | [
false
] | I'm really starting to wonder how darkness is affecting my behavior, state of mind, and habits. For example, when I am at work, there is tons of fluorescent lighting, I work hard, I am productive, I constantly read and write. When I get home, my blinds are closed because by the time I get home at 5:30 or so, it's dark ... | [
"So what you're saying is that you're confused about needing a nap after working all day and then eating a big meal?",
"\nSure the lights help you stay awake, but I suspect its mostly because we normally only sleep when its dark."
] | [
"Increased melatonin production."
] | [
"I don't eat big meals, but I do get a slight insulin from meals even though they are small, so I do take a nap after, the darkness does help of course. If it was light, I doubt I would take the nap.",
"My confusion is whether the darkness is affecting everything about me. I don't want to do tasks or work on stuf... |
[
"From the first Hydrogen-Hydrogen fusion event to reaching thermonuclear stability, how long does it take a proto-star to 'turn on' and become a real star?"
] | [
false
] | null | [
"No. In fact, the star gets less rowdy as fusion turns on. Proto-stars use convective heat transfer which is messy and unstable, leading to lots of big eruptions and flare ups. Fusioning stars use radiative heat transfer which leads to a more orderly internal layering of conditions that reduces the number of large ... | [
"It's complicated, and depends on the mass of the protostar. Massive stars can reach the main sequence in a million years or less, while the smallest possible stars (.08 solar mass) may take billions to reach the main sequence proper.",
"https://lco.global/spacebook/protostar/"
] | [
"The process of transitioning from proto-star to proton burning star is a gradual one. Proto-stars begin very hot and bright due to the energy from gravitational collapse (this heat, concentrated in the core, is what initiates fusion reactions, after all). It takes several million years for a newborn star to transi... |
[
"i ask this of /r/AskScience because I feel it to be a subreddit of more credibility than /r/Scifi"
] | [
false
] | Is there a good book/story about a group of beings Trying to create a preserve of life to survive the heat death of the universe? I've often wondered how some (Clarkian "magically advanced") group might attempt to forestall the inevitable. EDIT: I'm horrifyingly drunk right now and this question came up during discussi... | [
"There's an Asimov short called \"The Last Question\" that kind of deals with this.",
"http://www.multivax.com/last_question.html"
] | [
"The last question?",
"Edit: derp."
] | [
"Many thanks."
] |
[
"Blood pressure and oxygen delivery"
] | [
false
] | I'm having a little trouble conceptualizing the effect that blood pressure has on oxygen delivery. Generally oxygen delivery (DO2) is said to be a function of oxygen saturation, cardiac output, and hemoglobin (with a small contribution from PaO2). But if the blood pressure is very low, it seems obvious that tissue hy... | [
"Hi there, an interesting question indeed.",
"You are right, O2 delivery depends on oxygen saturation, Hb concentration, and Cardiac Output (CO).",
"You may know that CO = Heart Rate x Stroke Volume.\nIt is also equal to Pressure / Total Peripheral Resistance. \nThis last formula should help answer your questio... | [
"DO2 = (SaO2-SvO2) x Hb x 1,34ml/g x CO\nCO = BP / TPR\n\nDO2 = (SaO2-SvO2) x Hb x 1,34ml/g x BP / TPR\n",
"But this is not a helpful way of looking at it. If BP goes down, it can be because of:",
"If BP stays low, you have the following scenarios:"
] | [
"You can consider mean arterial pressure (MAP) in that equation, something of a perfusion pressure, if you will. In order for tissue/organs to get perfused, the MAP should be above 60. ",
"This actually gives a pretty good run-down on perfusion pressures and hemodynamic monitoring."
] |
[
"How are body cell-count and cancer likelihood related?"
] | [
false
] | Is someone with 20% more fat cells 20% more likely to get fat cell cancer? | [
"So of I'm tall, I want to be even thinner to keep the cancer risk down, right?"
] | [
"So of I'm tall, I want to be even thinner to keep the cancer risk down, right?"
] | [
"To add an interesting point: while what ",
"/u/turbo_speedwagon",
" said is true within a certain species, this does not hold true between species. Some larger mammals, like elephants for example, rarely get cancer due to upregulation of certain tumor-suppressors. ",
"https://jamanetwork.com/journals/jama/ar... |
[
"Is there a system of geographical coordinates in space?"
] | [
false
] | Let's say I want to tell someone exactly where was the earth 6 month ago in space. Is there some kind of system like on earth to tell a specific position in the universe? Given that earth is moving around a sun moving in a galaxy in an expending universe, I struggle to imagine a system of coordinate that could allow to... | [
"There is, and it's called the ICRS (International Celestial Reference System). It is an idealized set of coordinates, the current realization of which is called the ICRF (International Celestial Reference Frame) version 3.",
"Astronomical reference systems are based on the celestial sphere, which is the backdrop... | [
"That's all that could be said about that coordinate system. Unfortunately it can't really tell where we are \"in the universe\". But that's really hard and for observational purposes that your reference point is quite random and moves a bit doesn't really matter. So astronomers often stick to this\nBut if you want... | [
"There is no unambiguous \"this place but 6 months ago\". Such a description would need an unambiguous definition of \"at rest\" (staying at the same place), which does not exist. Something that's at rest for one observer will move for another observer and vice versa. Both views are equally valid.",
"All the coor... |
[
"Spilled battery acid"
] | [
false
] | null | [
"Baking soda and water.",
"Get it wet, and then add baking soda to it. As long as it's acidic, it'll keep fizzing. When it stops, add more soda. Repeat until new soda doesn't fizz."
] | [
"Wouldn't recommend it. Baking powder is baking soda with acid added, so it's not going to neutralize a lot of other acid."
] | [
"Will baking powder work?"
] |
[
"Why don't we feel pain during dreams?"
] | [
false
] | null | [
"What? I've felt pain in my dreams many times. Having a chronic illness will do that to ya.",
"It's interesting dreaming your in a car crash with a metal rod speared through your abdomen, then to wake and realize it's just some really bad stomach pains. Sucks waking up thinking your dying and then realize you pra... | [
"We do, just not very often.",
"Here",
" is a paper that surveyed 185 people and found that about half of them had experienced pain in a dream before. They also had them keep dream journals for a while and had 18 reports of pain dreams out of some 3000 or so total dreams. Only one was from someone who was actua... | [
"Considering the types of dreams I sometimes have, I'm glad I don't feel pain in them. I already can feel chunks of skull in my mouth, or my body slumping to the ground, that's horrific enough."
] |
[
"What's the best evidence that suggests that climate change is caused by humanity instead of something else?"
] | [
false
] | null | [
"Climate change is very complex issue, but I think the most straight forward argument is:"
] | [
"Well my layman's interpretation of things has been that, essentially Earth's climate has been fueled predominantly by two factors, energy from the sun and CO2 emissions. That throughout our history, ice ages have been caused by one or the other, or both, a drop in output from the sun, or a drop in CO2 in our atmo... | [
"Give this a shot"
] |
[
"What is the chemical process by which ADD drugs help normal college students concentrate for longer?"
] | [
false
] | Just curious about the effect on the brain | [
"With regard to the actual chemical process of ADD drugs, ADD drugs are typically drugs that are stimulants with similar action to cocaine or amphetamine (or in the case of Adderall, actually is amphetamine). These drugs mainly work at the dopamine transporter, (as well as the norepineprhine and serotonin reuptake ... | [
"That was interesting, thank you"
] | [
"One theory is that the prefontal cortex, the bit that helps the concious mind focus, stay on task, and filter out extraneous sensory input and thoughts is underaroused ( sleepy ) in individuals with ADD",
"The prefontal cortex acts as a censor and switchboard for your concious mind. Its a gatekeeper, filtering s... |
[
"Physics question: For K=(1/2)mv^2, how is K in Joules (a unit of energy) if the unit m*kg/sec is in Watts (a unit of power)?"
] | [
false
] | [deleted] | [
"m [kg] and v [m/s], therefore K = (1/2)[kg][m/s]",
" = [kg m",
" / s",
" ] = [J]"
] | [
"Also, you have your Watts wrong.",
"Power = Energy / time",
"Watts = J/s = kg m",
" / s"
] | [
"Also, you have your Watts wrong.",
"Power = Energy / time",
"Watts = J/s = kg m",
" / s"
] |
[
"Will leaving the bathroom light and fan on slow the growth of mildew?"
] | [
false
] | null | [
"Leaving the bath fan on will take humid air out of the room. This is a proven method to prevent mildew growth. It only grows where there is moisture."
] | [
"Does light have no effect on growth? "
] | [
"Not sure about that one. I know that UV light can help control mildew and that fluorescent lighting does emit UV radiation, but I am unsure as to the amounts and if it would affect growth."
] |
[
"Why would my son's doctor tell hm that he in fact \"broke every bone in his foot\" when he had broken 5 metatarsals?"
] | [
false
] | null | [
"We can't comment on personal anecdotes / isolated incidents without resorting to speculation which we try to avoid."
] | [
"Not sure I follow. It's rather like Question: My teacher said the tomato is not a vegetable; why would she tell me that? Answer: The tomato is a fruit. ",
"I suspect if there was an explanation like that made sense, I would have received it, so my take away is that she was in error. Thank you for your ti... | [
"We can't say why someone said something. That's not a science question."
] |
[
"How does your body know your old enough for puberty?"
] | [
false
] | I know that environmental chemicals and hormones can affect the timing by a few months or years, but I'm looking for the mechanisms for the biological "clock" of the development of your sexual organs. | [
"No the second \"your\". Like this:\nHow does your body know ",
" old enough for puberty"
] | [
"No the second \"your\". Like this:\nHow does your body know ",
" old enough for puberty"
] | [
"You're* "
] |
[
"Dangers of a penny on train track?"
] | [
false
] | When I was going through drivers e.d. I remember one story that stuck with me that begs the question of "is this for real?” During a drivers safety class they dedicated an entire hour to trains. For that hour we heard every way a person could be killed by a train. One story was of a child who put a penny on the train t... | [
"The same article also claims that ",
"Pennying the tracks can result in a further danger — sometimes those coins shoot out from under the train's wheels at incredible speeds, turning them into potentially deadly little projectiles",
"but doesn't cite any sources or incidents. I myself find it highly unlikely, ... | [
"A penny is very small and light and a train is extremely heavy and moving at speed. It's theoretically possible for the train to flick the coin off at high speed given the right conditions, but I'm not convinced it could ever reach a high enough velocity from that situation to penetrate a skull, and unless the chi... | [
"http://www.snopes.com/science/train.asp",
"Plenty of kids seem to have died trying it, at least. "
] |
[
"What determines handedness, and why is there such an imbalance of left and right?"
] | [
false
] | null | [
"Handedness is not binary, but is actually a spectrum. You can find out where you lie on that spectrum using this:",
"http://www.brainmapping.org/shared/Edinburgh.php",
".",
"Here's the paper if you care to read further into it:",
"http://web.psy.ku.dk/Anders_Gade/Readings/Oldfield1971.pdf"
] | [
"Handedness is not binary, but is actually a spectrum. You can find out where you lie on that spectrum using this:",
"http://www.brainmapping.org/shared/Edinburgh.php",
".",
"Here's the paper if you care to read further into it:",
"http://web.psy.ku.dk/Anders_Gade/Readings/Oldfield1971.pdf"
] | [
"This question was ",
"recently answered on AskScience",
", so you may find relevant discussion there. ",
"And I'd like to remind folks that comments containing anecdotes and personal speculation will be removed. Please base answers on peer-reviewed scientific literature."
] |
[
"What pattern would I draw on a map if I followed the suns direction for all the hours of daylight and stay put at night?"
] | [
false
] | Does the pattern change from winter to summer solstice? Does the pattern change from latitude and longitude changes? | [
"You mean, if you walked towards the sun all day at a speed negligible compared to Earth rotation? ",
"On small scales it would be something that looks very roughly like a rectified sine wave where the x axis goes towards the sun latitude, the y axis going east. The closer you get to the sun latitude, the more it... | [
"I assume you are asking how your path would look on a 2D map?",
"I think it would be a series of half ellipses that gradually flatten out to a straight line as you reach the sun’s latitude. When you are at that latitude, you would basically walk due East in the morning, slow down until the sun is directly overhe... | [
"xkcd (I think) studied this a few years ago, but I don't find it any more. If you are slow you should just oscillate back and forth close to the equator if I remember correctly."
] |
[
"How can anything be more than 13.7 billion light years away?"
] | [
false
] | null | [
"The expansion of the universe has caused objects to move away from us at a rate greater than the speed of light. As a result, their distance from us now is greater than the age of the universe times the speed of light."
] | [
"Two things:",
"First, for the most part, they've been emitting light continuously since they were much closer to us and thereby receding at a lower rate. We're seeing the light that was emitted at that time.",
"Second, we can even see some objects that have ",
" been receding from us faster than the speed of... | [
"Things that were 13 billion lightyears away from us 13 billion years ago, whose light is just reaching us now, are now farther away because the intervening space has expanded sine then."
] |
[
"If ozone has a higher molecular weight than oxygen, then why does the main body of ozone exist higher up in the atmosphere?"
] | [
false
] | I was under the impression that higher MW -> higher density. | [
"why doesn't it all sink to ground level?",
"Because the kinetic energy of O3 (at its temperature) is larger than the potential energy differences due to gravity. You might compare to a set of tennis balls and ping-pong balls in a box. If you shake the box around sufficiently violently, you're not going to get an... | [
"I know that O2 + UV light = ozone, but why doesn't it all sink to ground level?"
] | [
"I know that O2 + UV light = ozone, but why doesn't it all sink to ground level?"
] |
[
"How did this man travel through time?"
] | [
false
] | I am familiar (though I don't understand) the concept of moving so fast that the rate of time-if traveling through space- changes then if you were on Earth. Would this be the scientific reasoning behind "time travel"? | [
"The article is somewhat misleading. Due to the speed of his spaceflight, he experienced ",
"time dilation",
", and he has suffered through 20 milliseconds less time than us plebs back on earth.",
"Edit: Didn't read your post properly. So now my answer is \"yes\"."
] | [
"In the same way that I have time traveled here from the late 1980s."
] | [
"Honestly, I've never seen why this ",
" seen as time travel. If you had a super fast vehicle and did laps around the solar system for a bit to come back to an earth hundreds of years in the future, that sure seems like time travel to me. Just because time dilation is explained by science, doesn't mean that it is... |
[
"About what percentage of current American Citizens are descendants of colonial Americans?"
] | [
false
] | I am referring to the U.S.A and Britain's 13 colonies for clarification. Alternatively: How many American Citizens have ancestors who immigrated to the country? I realize that this could be a difficult figure to come up with, if so what is the best estimate we have/can make? | [
"I feel like the intent of the question was \"What % of modern Americans have ancestors that were here when the country became an independent nation?\""
] | [
"From the OP:",
"About what percentage of current American Citizens are descendants of colonial Americans?",
"Did you even read the title of the post?",
"Edit:",
"Even if you choose to answer the \"alternative\" question, from context you should realize s/he meant ancestors who immigrated to the country af... | [
"Just because I and a colonial-era American have a common ancestor in Africa, doesn't mean I have an ancestor in colonial America."
] |
[
"How many stars are contained within our radio bubble, and how fast is that number increasing?"
] | [
false
] | Just as the title asks, I have been unable to find and use a complete list of stars with their distances to calculate this. I suppose I could work it out based on the average density of stars in our galaxy, but I would love to see a realistic number. | [
"Assuming you take the date of radio discovery, and ignore the problem of signal strength, then you're looking at however many stars lie within about 130 light years.",
"It's a lot. ",
"This map shows all the stars within just 50 light years",
", and even then only the ones visible to the naked eye. There's ... | [
"133 is 10% of 1,330, not 13,300."
] | [
"It has nothing to do with decoding. It has to do with detection. Radio signals are just light of a kind we can't see with our eyes, and like all light, they fall off in intensity with the square of the distance (because light propagates as a sphere, and the surface area of a sphere goes by the square of the radius... |
[
"What is the tone of a sound?"
] | [
false
] | Like, I understand pitch and changes in frequency, but what is the tone difference? For example, a trombone sounds different from a trumpet. Two people singing the same notes can have radically different tones. What, scientifically, is that tone? Why doesn't it just produce the frequency of the sound? | [
"When a piano or a violin plays an A 440, what that means is that the note has a fundamental tone with a frequency of 440 Hertz, but it also has a set of additional frequencies in conjunction with that. What makes an oboe sound different from a clarinet, and both of them sound different from a violin, is that for ... | [
"The additional frequencies can be expressed as a combination of harmonics of the fundamental. The Fourier transform can take any periodic waveform from any instrument and convert it into a series of harmonics."
] | [
"I believe this is called ",
"Timbre"
] |
[
"Was the sky different colors through its history?"
] | [
false
] | I know the sky is the color it is because the current gases and their density absorb some colors and reflect mostly blue. However, the gases and composition of the atmosphere have changed over billions of years some number of times, so has the color changes as well? Was it ever more green or red? | [
"The ancient Earth had a methane rich atmosphere. Due to sunlight, some of the methane formed complex hydrocarbons that condensed into particles. The particles resulted in a pinkish-orange haze, according to ",
"this article",
"."
] | [
"The wavelengths of light involved in ",
"Rayleigh scattering",
" (the process that makes the sky appear blue) are independent of the composition of the atmosphere. The Rayleigh scattering factor is inversely proportional to the wavelength; in other words, shorter wavelengths (blue and violet) are preferentiall... | [
"I'm going to upvote this as a better answer than mine. A permanent haze (similar to ",
"Titan's atmosphere",
") would certainly qualify as a \"different color sky\"."
] |
[
"Are we all descendants of a single human being?"
] | [
false
] | null | [
"Wow, lots of half-right answers here. In short - we are descendants of a single pair of human beings: Commonly called (rather journalistically) Mitochondrial Eve and Y-Chromosome Adam. However, these were not necessarily a mother and father pair, nor were they necessarily alive at the same time. ",
"This is what... | [
"All women are descended from ME…",
"It took me two solid minutes of thinking to figure out that you weren't just emphatically asserting your virility here."
] | [
"No, speciation is something that happens to a population, not an individual."
] |
[
"Are all atoms or particles of a particular type precisely identical?"
] | [
false
] | I know any two hydrogen atoms or protons or what have you are identical, but are they all precisely identical? Is there any reason to think that the mass of two protons would vary slightly, or is it fixed in some fundamental way? | [
"Protons etc are truly identical. The evidence for that is that it gives rise to the particular weird properties of quantum mechanical systems of bosons and fermions.",
"Atoms are also truly identical ",
" they're of the same isotope."
] | [
"Some atoms are bosons, some are fermions. Everything with an integer spin is a boson, everything with a half-integer spin is a fermion.",
"EDIT: Some effects that this implies? If you take some bosonic ions (charged atoms) you can put them into an ion trap and have them undergo Bose-Einstein condensation. ",
"... | [
"Of course, yeah. Atoms have internal structure and thus two atoms of the same kind can be in different states. But that doesn't change the fact that they'll have the exact same internal structure, same energy levels, etc."
] |
[
"What's something that was incurable 10 years ago which is curable now?"
] | [
false
] | people actually like if their condition is incurable now, it's going to be that way for the rest of their life. How hopeless is it really? I know cancer has not been cured what about other things. Is there any decent chance that neuropathy will be cured soon? What has been cured in the last decade? | [
"They invented ",
"sofosbuvir",
" and basically cured hepatitis C virus. Has been very controversial over the cost... a 12-week course of treatment costs about $84,000. But this gives a 95% success rate, so they are basically selling a product that is putting itself out of business. And they would argue they ha... | [
"I know cancer has not been cured ",
"Lots of cancers have been effectively cured. Especially childhood cancers, some of which have gone from survival rates of less than 10% to greater than 90% (see ",
"Twenty years of follow-up among survivors of childhood and young adult acute myeloid leukemia: a report from... | [
"Yes, that's something charlatans frequently use to explain why their miracle berry/mineral/widget will cure your disease, but it's not common knowledge because the \"big drug companies\" don't want you to know.",
"In reality, there are many reasons why companies are motivated to cure diseases. ",
"The first i... |
[
"Is there a genuine scientific reason why you shouldn't refill bottled water bottles with tap water, as some companies seem to claim on their labels?"
] | [
false
] | null | [
"I have honestly never seen that claim before, but I could guess that in some regions the tap water could be considered unsafe due to bacterial contamination. You wouldn't want that in your bottle.",
"I also had a funny discussion with one of my organic chem teachers a long time ago when she saw us drinking bottl... | [
"nah, ",
"Phthalates",
" are still widely used, in fact they are so widespread that you can basically find them anywhere in our environment nowadays. If I remember the number correctly the global production of ",
"plasticisers",
" in 2014/2015 was like 8-9 million tons (I think it's stated somewhere in the ... | [
"I know of two reasons that this might be the case, although only one is scientific.",
"First, the non-scientific reason is that the company has certified the quality of the water in the bottle, and put their label on it. If you re-fill it, the quality will not be the same. (Arguably, it may be as good or bette... |
[
"What is an electriic double layer capacitor and how are they different from a standard capacitor?"
] | [
false
] | null | [
"Result: a capacitor charged with low voltage over a long time can kill you because it discharges at high voltage in a short time",
"The only way for a capacitor to get a higher voltage than that which charged it, is by pulling the electrodes apart. That action does work against the charge, which results in a hig... | [
"They are formed by the ",
"electrolytic double layer",
"/) that forms at the negative electrode. It is a layer of typically two ions thick of hydrogen atoms on the surface of the electrode. This polarization represents a stored charge. It is extremely larger charge than what occurs in a conventional capacitor,... | [
"Technically, capacitors store energy which is converted to volt-amps when discharged depending on the resistance of the discharging circuit and the internal resistance of the capacitor. Result: a capacitor charged with low voltage over a long time can kill you because it discharges at high voltage in a short time.... |
[
"Will missile defense technologies ultimately tame ICBMs?"
] | [
false
] | null | [
"Hello,",
"This would be more appropriate for ",
"/r/AskScienceDiscussion",
".",
"Best."
] | [
"Ok thank you!"
] | [
"And in a more general sense, do you believe that defense technologies will out pace attack technologies, helping to reduce the possibility of mutual destruction in the longer term."
] |
[
"In a future where fossil fuels no longer existed what building materials would be used to replace steel and concrete?"
] | [
false
] | If fossils fuels were no longer abundant and therefore could not be used to produce energy for the production of steel and concrete what materials would be use instead? Assuming some other energy source is able to power machines to mine the required materials but not enough energy to power the equivalent of the product... | [
"No, he is saying that steel and concrete require energy, not fossil fuels. If fossil fuels run out today those industries would instantly switch to renewables, it's not an issue at all for them. Both steel and concrete require heat to produce, and if suddenly an electric furnace was 10 times cheaper than a gas fur... | [
"Mostly, if all you need is heat, it's more efficient to go straight to the heat. Electricity generation systems have inefficiencies in turning whatever their energy source is into electricity, e.g. fossil fuel combustion or nuclear reactions produce heat, heat engine turns some heat into work (~30-40% efficiency ... | [
"If the energy use in production were a concern, I'm not sure it'd ever just get to a point where, suddenly, we can mine but can't do any production at all. Why should we assume that production and not mining would necessarily even be the bottleneck here? Anyway, surely it'd just get more expensive, and projects th... |
[
"Why do airplane windows need to have that hole?"
] | [
false
] | null | [
"\nForemost. ",
"It has the function of demisting the outer window as well.",
"The structure is as follows. Outer pane and middle pane form a unit. Middle pane has a small breathing hole. On the inside of this unit is a quite large air gap and then the inner pane.",
"The outer and middle panes are load beari... | [
"Its a safety procedure, so if something happens during landing/takeoff, crew and passengers can easily see outside and rescue crews can easily see inside. "
] | [
"There are two windows: the first one is to separate the plane and the outside, the second one prevents you from touching the first window since it is very cold when in flight.",
"\nBecause there are 2 windows, we have a space between them which should be at the same pressure as the inside of the plane (otherwise... |
[
"What causes sunscreen to lose potency over time after application?"
] | [
false
] | Why is it that sunscreen only lasts a limited amount of time after application? Is it that it wears away, or that more sunlight is able to break through it over time, or what? | [
"It has always been my understanding that over time it is washed off or worn away by water/sweat/rubbing (like wiping your eyes to get water off takes a little sunscreen with it).\nMy dad (the protective doctor) has always recommended re application every 3-4 hours if you are just outdoors and every 2 hours when sw... | [
"On ",
"/r/skincareaddiction",
", I read that the skin absorbs some of the sunscreen over time, so it's no longer a barrier on the surface of the skin. Apparently that's why some powder SPFs are recommended instead."
] | [
"So if I put sunscreen on and just stand there, then I could not get burn for hours?"
] |
[
"Is there any evidence that time is dimensional?"
] | [
false
] | By dimensional time i mean like a film strip where the past and future exists or is it more like motion in the sense that there is just a present that is always changing? | [
"Think of a 2D plot with space as one axis and time as another. Events all have a time and space coordinate. Einstein showed that when you change your velocity, the time and space coordinates \"mix\" together and rotate/twist around eachother.",
"For example, let's say you had two events, one at (0,0) and the o... | [
"Well...I'm not sure this is evidence enough for you, but we can \"rotate\" time (that is, two events separated only by space and not time can be rotated so that they are separated by both, and two events separated by time but not space can be rotated so that they are separated by both), mixing time and space toget... | [
"Sorry im not sure i understand, how can we rotate time?"
] |
[
"Why does beer/soda carbonate better when cold?"
] | [
false
] | So there is a discussion going on in regarding carbonating beer. My mother-in-law, a long time homebrewer that under forced carbonation in a keg, beer will carbonate faster cold than if you carbonate it at room temperature. I've seen this occur myself. The absorption rate is very slow when warm, but the solvent will ta... | [
"Carbon dioxide ",
"dissolves better in cold water.",
"Also note that carbon dioxide dissolved in water forms carbonic acid:",
"H2O + CO2 <--> H2CO3",
"The reaction is reversible, of course.",
"Things start to get complex from here, but this reaction also explains why you get \"sand\" in your hot water h... | [
"It's not so much a function of polarity as a function of the temperature ",
"What you are describing is a function of [Henry's Law].(",
"http://en.wikipedia.org/wiki/Henry%27s_law",
")",
"\"At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly ... | [
"It seems counterintuitive from a high level, as I would assume the water molecules would be more open and swimming around faster when warm, and would be more will to mix with CO2.",
"And it is intuitive that if you shook a beer or other carbonated beverage that the gas would become more entrenched or more likely... |
[
"Zero-calorie sweeteners: What are these substances? What exactly am I putting into my body? Why is there a choice, and which is doing the least damage to my health? [pic inside]"
] | [
false
] | This always bothered me. Why is there a choice of FOUR different sweeteners, if they all taste EXACTLY the same and all they do is sweeten my coffee? | [
"So let's look at the four you've posted:",
"Apart from the business concerns of competitive sweetener manufacturers, the variety exists to meet other needs as well. Consumers concerned with 'natural' foods will gravitate towards the erythritol/stevia blend, and aspartame will be avoided by phenylketonurics, thos... | [
"Well, why do you have more than one brand of ketchup or whatever? That's the free market.",
"What you're putting into your body is simply chemical compounds which activate the same molecular sensors as sugar, but which don't have the same metabolic content. The ones you linked to also contain sugar (dextrose, ma... | [
"Aspartame is a protein. It has the same number of calories per gram as sugar. However, it is 200 times sweeter than sugar, so you can use 1/200th as much to achieve the same level of sweetness and end up with a 0 or 1 calorie drink. ",
"I believe other artificial sweeteners work on the same principle. "
] |
[
"Is it true that the human brain is the least developed brain of all mammals at birth?"
] | [
false
] | I was watching a documentary and a psychologist made the claim. I looked online but I couldn't find anything. | [
"I believe the reason for this claim is that the ratio of birth size/weight to brain size/weight in human infants is unusually large and consequently takes much longer to develop. Some animals can even walk after being born. However, with humans, that would be crazy. ",
"Humans take a huge amount of time to deve... | [
"It's not true, marsupial babies are born at a less developed stage than any placental mammal. And lots of mammals have small, helpless babies...mice and rats and bears, to name a few. At least humans have their eyes open! ",
"But humans do have relatively undeveloped brains especially when compared to other p... | [
"Hey, thank you for the answer.",
"I'm wondering if you have any sources? I want to debate the point but I don't want to seem ignorant "
] |
[
"If atoms only emit light with specific (discrete) values for wavelengths, why do bodies emit a continuous spectrum of radiation?"
] | [
false
] | [deleted] | [
"A black body is an idealized model, like a perfect vacuum or a frictionless surface. It is an approximation which holds up well in many cases, but actual things deviate from the black-body model.",
"The hypothetical black body is a substance that absorbs all light perfectly, and emits light in a well-defined spe... | [
"But if you took a huge ball of hydrogen, like the sun for example, and heated the whole thing up to 6000 kelvin, it follows the black-body model quite well. At this temperature, we happen to get the spectrum we are familiar with from the sun.",
"Even in this case, there are still some pretty strong peaks, but as... | [
"For my answer I'm relying on \"Optical Coherence and Quantum Optics\" by Mandel and Wolf as well as Yariv's \"Quantum Electronics,\" both bibles in their respective fields.",
"Although the previous answers are good, they are far from telling the complete story and in my opinion carry a few misconceptions.",
"A... |
[
"What happens to the electricity generated from a solar panel if nothing is using it?"
] | [
false
] | If you have a solar panel sitting in the sun, but no load is connected to it and nothing is using that power, what happens to the energy? Does it get dissipated elsewhere? Will the solar panel overheat? | [
"There will be potential energy but until there is a path for current to flow no actual energy will be produced. ",
"Sort of like a battery it has tons of energy stored but there is no heating until there is a pathway for it to move. The release of energy is where the heat comes from."
] | [
"There will be electric potential generated by the cell, and it will behave almost like an open circuit. In all of these devices, there are second-order leakage effects. While most of the energy you generate is getting stored electric potential, some of it is burned inside the semiconductor solar cell itself. Th... | [
"1) There is no \"electricity\" being generated if the circuit is open. The voltage between the two leads on the module can be measured, and is known as Voc, or Open Circuit Voltage. ",
"2) \"What happens to the energy?\" The modules rise in temperature just a little due to the solar energy not being converted ... |
[
"Is it possible for us to properly assume what's further beyond the observable universe? (Other minor questions inside)"
] | [
false
] | null | [
"Is it possible for us to properly assume what's further beyond the observable universe? (Other minor questions inside)",
"Well, cosmologists largely operate under the assumption of homogeneity; i.e., that the universe is largely the same everywhere. Our observable universe appears to be largely homogeneous (modu... | [
"Thank you very much!"
] | [
"I think the possibility of cosmic isolation is both fascinating and terrifying at the same time. I just wish i'd be around to see how things pan out. :/"
] |
[
"How effective is mouthwash? How close to \"sterile\" does it make your mouth and for how long? (Both non-alcohol and alcohol versions)"
] | [
false
] | It seems pointless to me to try and sterilize your mouth for about 20 minutes (or however long it takes for the bacteria to get back to a normal population). I still use it though (non-alcoholic one) after using a tongue scraper because it makes my breath fresher and mouth feel cleaner. How effective is the best tongue... | [
"Mouthwashes in a nutshell:\nThe only effective mouthwashes are Listerine, Crest ProHealth, and ACT (fluoride mouthwash). Everything else is like a breath mint in liquid form. Your mouth will never be sterile, no matter how long you swish. Additionally, it's bad to swish for longer than recommended because it will ... | [
"Should one rinse their mouth with water after using a mouthwash or not?"
] | [
"The process is the same as a chemical burn from overuse of mouthwash. The trauma causes the need for rapid cell turnover, which leads to dysplasia. I have fitted a few people for nightguards because they would tear their cheeks up at night."
] |
[
"If it is a common misconception that your heart is on the left side of your body (and it's very much in the centre), why do you feel pain in your left arm first when a heart attack starts?"
] | [
false
] | null | [
"It's a misconception that heart pain starts jn the left arm. That is largely a Hollywood invention. When pain is present, the most common location for it is in the center of the chest, and it may radiate in a variety of directions-- for instance to either arm, the jaw, or the back of the shoulders. ",
"(A large ... | [
"It is more to the left than you think.",
"\nFrom what I've studied, internal organs do not have nerve endings responsible for pain perception, therefore during organ failure or distress, nearby surfaces will react to the problem (as in the case of the shooting pain associated with appendicitis). This can be in b... | [
"Good question, what you said makes sense. It's possible there was never a need for pain receptors since these organs are usually protected by body parts that do have pain receptors. One would think it would be useful for some organs to have pain receptors such as the heart or brain, but as we know, brain surgery i... |
[
"What is the fastest we've been able to accelerate a heavy element? For example, how fast have we gotten really heavy metals to accelerate in a particle accelerator, nuclear blast, etc.?"
] | [
false
] | null | [
"The LHC accelerates lead nuclei to roughly 99.99994% the speed of light. The RHIC does similar but with gold."
] | [
"I don't know if this is along the lines of what you were talking about, but it's very interesting nonetheless; during the nuclear tests in the 1950's a steel manhole cover was accelerated out of a test shaft by a nuclear blast. Scientists had a high speed camera trained on the manhole cover, which only appeared in... | [
"If we'd accelerate a radioactive nucleus to those speeds would decay slow down from our point of view?"
] |
[
"Why are toddlers and infants always putting things in their mouth?"
] | [
false
] | Is it to build immunity to bacteria? To explore their surroundings? Or is it simply just a quirk that they seem to exhibit? | [
"Exploring. Infants don't actually put things entirely inside their mouths very often, instead they bring them to their lips. This is because their lips are more sensitive and have better motor control and sensory feedback than their hands and fingers at that age, so they're better at exploring textures and shape... | [
"depending upon age, it is mostly to do with teething. (",
"http://en.wikipedia.org/wiki/Teething",
")",
"If you had sharp teeth emerging from your jaw, penetrating your skin, you'd be chewing sticks too.",
"(and remember, we're just apes, dealing with all sorts of plastic stuff lying around)"
] | [
"I also want to comment that younger babies have an awful sense of vision (its blurry shadows and colors for months), so tactile information would be the easiest to get"
] |
[
"For this last flu season: \"Hospitalization rates in children 0-4 years old and adults 18-49 years old are the highest on record according to the CDC, surpassing the rate reported during the 2009 H1N1 pandemic.\" How is this possible with a quarantine during part of this last season?"
] | [
false
] | null | [
"Flu season ended before the lockdown could really have any effect. The page that you posted says that the flu season ended on april 4th, shortly after the lockdown started. The peak of the flu season was much earlier and should have been largely unaffected by the lockdown."
] | [
"Check out this link for the ",
"Weekly US Influenza numbers",
". You'll see that the majority of the cases peaked in January. In fact, after March, which is when most states implemented their quarantines, the cases drop sharply.",
"This last flu season started earlier than usual."
] | [
"Got it. ",
"I thought the flu season went until June when I posted this."
] |
[
"Why does our skin itch?"
] | [
false
] | null | [
"This has been discussed a few times before, best to ",
"search",
" first."
] | [
"I don't know."
] | [
"Mine doesn't itch. You should go see a doctor."
] |
[
"How do microbes in the human body survive our immune systems?"
] | [
false
] | Is there a constant struggle between the non-human organisms and our immune systems or do they operate without issue? | [
"It's not clear what \"microbes in the human body\" you're asking about. In general, there are very few microbes in the human body, and most of those that do get there are rapidly eliminated by the immune system.",
"But what about the enormous numbers of bacteria, etc, in the digestive system? Strictly speaking... | [
"The immune system performs surveillance within the body looking for antigens. Antigens are proteins recognized as foreign. This is done via toll-like receptors (TLRs), circulating antibodies, and major and minor histocompatibility complexes (MHCs). The immune system will immediately and vigorously attack and attem... | [
"To add to the other comments, I want to emphasize that bacteria and other microbes like viruses and fungi also have defense mechanisms against the host immune system (they can block phagocytosis, the oxidative burst response, NETs, etc). Similar to the Red Queen hypothesis, bacteria have evolved alongside their ho... |
[
"Does the conditional expression of a transgene in a mouse model ever trigger an immune response?"
] | [
false
] | As an undergrad I worked with a few mouse models in which we got the mice to express the human form of a few signaling molecules and a receptor protein, but expression was delayed until adulthood. In a model like that, what is to stop the new protein from being recognized and acted upon as a foreign antigen? | [
"Not all transgenic mice are SCID. I think the responses here are due to variations from field to field....it would have been very hard for me to study allergic airway disease using inducible transgenes in SCID mice! So yes, they were quite immunocompetent...too much, sometimes. ",
"Typically, it's because no ind... | [
"Interesting question. I don't know how a normal mouse would react, but most of the time you make transgenic mice that you use a model that has SCID (Severe combined Immunodeficiency) so it wouldn't matter anyway."
] | [
"Like Bored says, if there is nothing stopping the immune response, a immune response will be mounted against the protein.",
"The same is true when the transgene encodes a hairpin sequence, such as used in RNA interference studies. Long double stranded RNAs will induce the interferon pathway, leading to cell deat... |
[
"Why don't electrons traveling in the orbitals of atoms lose energy, although they are a mass traveling a narrow space which should require some kind of acceleration to stay close to the atom?"
] | [
false
] | As I learned in physics the acceleration of a mass (and the change of direction is an acceleration) results in a change of kinetic energy, so traveling in a narrow space like an electron around an atom requires acceleration to change the direction of the electron to stay around the atom, so then why are atoms stable at... | [
"This is a good question, and one of the questions that led us away from the classical model of the atom and towards the quantum model. You are correct that the classical way we think of an atom (positively charged nucleus, negative particle in a circular orbit around it) would emit radiation, causing the electron ... | [
"when it is in an excited state it is no longer a standing wave ",
"I understand that an excited state is not a ",
"stationary state",
" and that stationary states are always ",
"standing waves",
" but does not-in-a-stationary-state necessarily also mean not a standing wave (a travelling wave)?",
"\... | [
"Good Question. A stationary state is just a state that is time independent in all \"variables\". (So solutions to the time independent Schrödinger equation, more specifically eigenstates with eigenvalues). So a non-stationary state doesn't have to be a \"completely\" non-standing wave, it can be a standing wave th... |
[
"Why is the distribution of precious metals concentrated in \"veins\" instead of evenly distributed throughout the planet?"
] | [
false
] | I am rewatching "Deadwood" (which is a great show) and had this thought. Why did the Black Hills have gold and other places don't? It seems like everything being random, you would expect an even distribution of gold across the planet. | [
"Oh man, one could go into a ",
" of depth with this question. I would love to, but I'm short on time so I'll just point out a few things.",
"First, not every part of the planet has the same sorts of rocks. Some places have sedimentary rocks (sandstones for example), while others have volcanic rocks (basalt and... | [
"If I'm understanding your explanation correctly, it seems like you'd very often find certain minerals close to each other, which in turn could tell you that you're close to hitting paydirt.",
"For example, Element X has a crystallization temperature just a few degrees cooler than Element Y. As the temperature dr... | [
"Yep, good thinking, this absolutely occurs. For something like gold, there is no absolute identifier that I know of (though this is rapidly deviating from my study area), but it is definitely correlated with many minerals. What minerals will depend on how your gold in the region is being concentrated, which can be... |
[
"What is the actual effective lifespan of motor oil in a car engine?"
] | [
false
] | I understand that the average mechanic will tell you to change your oil every ~2500-3000 miles (which we all know is far too soon anyway, right?). My main question, instead, concerns the lifespan of motor oil in a car's engine in terms of time. If I barely use my car--let's say I drive it roughly 1000 miles per year, h... | [
"Bonus question: What is a good actual mileage for when oil should probably be changed assuming regular, urban/suburban driving?",
"Read the owner's manual for your car. The manufacturer's recommended number is based on their knowledge of the engine and the type of oil that the manufacturer and dealerships buy. F... | [
"If the manual says your engine can go 15k with any oil that meets some specified industry standard (e.g. American Petroleum Institute Service SN), feel free to take that at face value."
] | [
"I agree, but just a clarification that \"7.5k or 15k\" depends on different oil types that can be used on the engine. Don't go 15k on a 7.5k oil.",
"But next time you change your oils, you can ask your repairman for a higher mileage oil perhaps."
] |
[
"Is gravity a fundamental force like the other three? [physics]"
] | [
false
] | I thought that matter just by being matter curved spacetime and that all gravitational interactions were just the results of objects traveling through the curved space. So, it seems more like just a property of matter and not an actual force, but I'm sure this is probably just a semantics issue and that, also, I may be... | [
"Gravity is a force because it accelerates mass. It's a fundamental force because it acts at a fundamentally different scale and strength than the other forces. ",
"Your question seems to be more related to unification. Right now gravity is described by a classical theory involving curved space and whatnot. The ... | [
"Gravity is indeed considered a ",
"fundamental force",
". It differs from the others, however, in some ways: it is always an attractive force (at least so far), and moreover has not yet been successfully united with the others. Also, gravity is described by ",
"General Relativity",
" (GR), while the other ... | [
"What does it mean that reality must be local?"
] |
[
"Can a bird track down a moved nest w/ eggs?"
] | [
false
] | The other day in my apartment building, a neighbor on the 9th floor found a pigeon had built a nest and laid eggs on her balcony. The maintenance guy came and moved it down along the building and put it up in a tree. I've been worried sick since she told me that this pidgeon mother has been flying around frantically lo... | [
"If a nest is moved there is a very good chance the bird will abandon it/not find it. Sorry to be the bearer of bad news. It is still early in the season so she will hopefully start a new nest somewhere else. \nSorry :(",
"Source: Cornell Lab of Ornithology FAQ",
"Edit: Pigeons (rock doves) nest on ledges (such... | [
"As a follow up, would OP be able to put bird feed to attract the bird? Would the bird be able to know its their offspring?"
] | [
"If one would put the nest back on the balcony, would the bird then be able to find it? Or is it too late for that?"
] |
[
"Can we detect relative high ground-levels of radiation from Orbit? Would an Astronaut on the ISS holding a geiger-counter into the general direction of Earth when passing over Tschernobyl or Fukushima get a heightened response compared to the Amazon rainforest?"
] | [
false
] | null | [
"Alpha radiation only travels a few centimeters in air. Beta radiation will travel a few meters. Gamma radiation will travel about a kilometer. Even if you could detect the extremely low signal from the effects of the inverse square law (which would be almost certainly be lower than the natural background radiation... | [
"Have a PhD in experimental high energy physics….can confirm. No way you are going to detect these in any quantity on the space station…..maybe with a very long probe? Lol"
] | [
"Unlikely.\nYou would need quite sensitive instrumentation in the first place as the intensity of radiation drops to a quarter of its value every time you double the distance (known as the inverse square rule).",
"There is quite a bit of electromagnetic radiation kicking about up there so you would need to furthe... |
[
"Where will the moon go when it eventually leaves orbit?"
] | [
false
] | We know that it moves x cm away every year, but are there any simulations that show where it will go? Into the Sun? Intersteller space? Possibly disrupt or orbit of or impact nearby planets? | [
"You know the moon moves to a higher orbit, but you are only seeing one side of the equation. The energy to move to a higher orbit has to come from somewhere. It his stolen from the Earth's rotation:",
"http://en.wikipedia.org/wiki/Day#Introduction",
"The Earth's rotation is slowed a bit over time. The Earth's ... | [
"tidally ",
"locked"
] | [
"The sun will engulf the Moon and the Earth long before it leaves Earth's orbit."
] |
[
"Is there a delay in which the brain detects/perceives motion?"
] | [
false
] | I have noticed a slightly odd 'phenomenon' when trying to detect motion of small objects. Specifically when I had a quartz watch and I glanced to look at the time I always felt like the first second took an unusually long time (relative to a second) before the hand ticked and the watch then seemed to continue about its... | [
"What you're describing is ",
"chronostasis",
", more commonly known as the stopped-clock illusion."
] | [
"Not only is this a thing, it has a name and is described by the very example I gave. How fascinating!",
"I could not find any references to this online! Thank you so much for the reply!"
] | [
"Its called the stoped clock illusion,",
"When you move your eyes, your brain overwrites the period where you see a blur with the first thing that you see clearly. So if you look at a clock the first second will appear longer because your brain added the time that your eyes were moving to the 1 second.",
"You ... |
[
"Human Genome Data Question"
] | [
false
] | The human genome contains roughly 725mb of data . Of this, only about 1% of humans genetic material differs. As wikipedia states, this difference can be expressed in roughly 4mb of data. 8 bits to a byte, 1024bytes to a kb, 1024kb to a mb, and 4mb worth of difference. That's (roughly) 34,000,000 genes (bits) that diffe... | [
"WolframAlpha's answer for 34M!",
"Assuming you have 34M base pairs, you don't want 34M factorial, but 4",
" which is a somewhat smaller astronomical number."
] | [
"No, you would not be guaranteed a doppelganger, because human genetic variation is not fixed. The error rate of DNA polymerase is very low, but high enough that every individual has dozens of novel, ",
" mutations that are private to them. You would need a much, much larger population to have a reasonable expect... | [
"It seems that they're drawing their figures from encoding a single base pair as two bits (I'd assume something like 00 = A, 01 = T, 10 = G, 11 = C). But I'm not sure whether that's taking into account the fact that these base pairs are arranged in codons, which code for 20 amino acids, which you could encode with... |
[
"Bacteria are able to harvest many compounds for energy. But are there bacteria that can live from electrical energy?"
] | [
false
] | Right now, I am studying citric acid cycle, oxidative phosphorylation and other energy related cell mechanisms. Googling about, I realized that bacteria have evolved to harvest almost all conceivable energy sources. Furthermore, scientists have been able to modify some strands to "eat" some compounds they were not able... | [
"Yes. Well, ",
"sort of",
".",
" are forming living wires that connect electron-rich upper sediment with the electron-poor deeper sediment. It is taking advantage of a natural electrochemical potential - in other words, a living wire that's feeding off a battery. Tell me that's not cool. ",
"Study",
"Inje... | [
"Woah! Thank you! That's more than I bargained for :D ",
"And yeah, I know about that. ATP is considered sort of a hormone when in interstitium or circulation. Fun fact: when erythrocytes go through capillaries, if the diameter is too small for them to pass, they burst and spill all their ATP, causing capillarie... | [
"I can think of no theoretical reason why such a bacteria couldn't exist. The practical reason for why one doesn't exist already is that free charge differentials aren't very common in the natural world, don't tend to last terribly long, and don't occur over distances that would allow a bacteria to travel from one... |
[
"Is it actually possible for the human mind to \"multi-task\" in the truest sense of the word?"
] | [
false
] | Is it possible for the human mind to simultaneously be consciously thinking of two things at once? Yes, I realize it's possible to be thinking two separate things while quickly switching between the two, but I don't believe we're conscious of both thought processes at the same time. For example, if I gave someone 3 s... | [
"No, we always switch between things quickly, and there seems to be a \"bottleneck\" of cognitive processing somewhere that restricts us to this strategy. Hal Pashler has several (e.g. ",
"1",
", ",
"2",
", ",
"3",
") papers on this phenomenon."
] | [
"Thank you for the great answer, I'll have to look over these studies when I get a chance."
] | [
"Well, i think you are asking a psychological question. You can't be dual cognitive. You are either aware or you're not. ",
"The brain with it's circuitry is truly a parallel processing machine. Natural functions while still being cognitive. "
] |
[
"Why does fabric and paper become so hard and rigid after being wet and left to dry?"
] | [
false
] | Ever left a wet paper towel on the counter? or a wet tshirt outside on a rail? When it eventually dries, its so hard that it can retain its shape. Why is this? | [
"This was asked before. I think the answer was that it allows/facilitates the fibers to become disordered. "
] | [
"Here it is:",
"http://www.reddit.com/r/askscience/comments/no35z/why_does_my_washcloth_go_into_the_shower_very/"
] | [
"Some paper has starch added to it for strength. I know copier paper and envelope paper do, and it is possible that paper towels have a small amount of starch. That can make the paper stiffer when it dries. "
] |
[
"How can it be that after 30 seconds of washing with warm soapy water, I can be reasonably sure the salmonella and e. coli are dead/gone, but my hands still reek of garlic and lemon juice?"
] | [
false
] | After I cut up some chicken and make a marinade? | [
"This is actually more of a chemistry question and has to do with polarity. ",
"All substances are either polar or nonpolar. We use the phrase \"like dissolves like\" when trying to determine what to use to dissolve something. Water is very polar, which means it is great for dissolving other polar things. The pro... | [
"It's the same story for the lemon juice as well. Just look at that sucker. That's about as nonpolar as it gets right there.",
"Interesting thing about limonene it's chiral and only the r-enantiomer smells of lemons. The l-enantiomer smells of pine trees. "
] | [
"While this might be one point, I'd more lean towards our sense of smell being much more sensitive to even a tiny amount of molecules in the air, whereas a considerable amount of bacteria is needed to overpower our immune system, stomach acid, etc."
] |
[
"Would the pressure at the center of the earth be zero?"
] | [
false
] | I've always assumed that the deeper you go into the earth, the greater the pressure. And anything I've ever read about the suggests tremendous pressure. But when you think about it, this is the of the entire earth. It's that point where there is equal amounts of mass pulling in all directions. If the earth were hypothe... | [
"Pressure and gravity are not the same force. While it's true that an object near the center of the Earth would experience nearly no gravitation, the pressure from the matter surrounding it would be immense. Remember, gravity isn't just pulling you towards the center of the Earth, it's also pulling the Earth towa... | [
"This is fundamentally wrong. The gravitational force at the centre of a uniform sphere is zero. This is quite easy to show mathematically; Newton knew about it. What you're saying is only true if you're outside the spherical mass.",
"The earth is close enough to uniform for the purposes of this discussion.",
"... | [
"You are conflating gravity and pressure. One is dependent on the other but they affect things differently. ",
"Pressure: the pressure increase as you approach the center. Pressure, in a fluid (or at least semi-fluid) presses on you in ",
" directions.",
"Gravity: while Newton's formula would indicate gavi... |
[
"Will GSM/CDMA be completely phased out in the lifetime of LTE?"
] | [
false
] | Will 2G be phased out in the next ten or so years? My biggest gripe with CDMA over GSM is being forced to use Verizon/Sprint/US Cellular/etc phones. In the event that GSM/CDMA is done away with and LTE takes hold as the primary wireless phone technology, will I be able to use non-carrier specific phones on any LTE ca... | [
"Well this gets off science a little bit, but I'll answer anyways. It's hard to predict business plans of course. However, since LTE can support more users (much larger bandwidth allotment and far better spectrum utilization) more per dollar spent (thanks to licensing and tech improvements) I will predict that it... | [
"Oh sorry, I didn't even answer the inner question. Most likely we will reach a point with everyone roaming to anyone. There will be issues with which bands different phones can tune to, but the tech is there, it'll be up to the businesses to allow it. ",
"One of the nice things about LTE is that the name is t... | [
"Thanks for the reply. My primary concern is the limitations on phones imposed by cdma carriers and I was hoping the science of what LTE does would help me understand if that would ever go away. Odds are Verizon and the like will never get rid of their iron fist management."
] |
[
"Can you explain what happens on a cellular level what happens to bacteria/viruses when hand-sanitizer (ie alcohol) touches them?"
] | [
false
] | Just interested to see the chemical reason as to why it's meant to kill "99.9%" of germs. | [
"Ethanol - the main alcohol found in hand sanitizers is bactericidal, meaning it kills bacterial and viral cells.\nIt affects the lipids in bacterial cell walls - which are composed of a phospholipid bilayer. It makes them more soluble to water, so the cell begins to lose it's structural integrity and causes the ou... | [
"Thanks Jess! I can consider this mystery solved. "
] | [
"Why does ethanol have this effect so strongly on bacterial cell walls but not on the cell walls of our skin cells? And what effect does it have on muscle cell walls exposed in a wound? Is the \"sting\" of alcohol on a wound the sign that human cells are being damaged?"
] |
[
"What is the ideal liquid to fall into from a great height? How big of a fall could you survive?"
] | [
false
] | Obviously, falling into water is much safer than falling onto a solid surface but there's a limit to how far you can fall before you've built up too much speed to survive the deceleration. Most people (barring extremely rare occurrences) die after jumping off the Golden Gate (220 ft / 67 m). Cliff divers on the other h... | [
"I think a better question would be: Is there a liquid that will allow you to survive a terminal velocity impact? "
] | [
"and if so, would you be able to get out?"
] | [
"I agree, low density is the important thing here. If you could find a very compressible liquid that would also help, but I don't know any liquids offhand that aren't basically incompressible. The pressure you'd experience hitting the surface would depend on how quickly the liquid could accelerate away from the i... |
[
"If the amount of CO2 in the atmosphere was instantly cut in half, (we don't want to kill the plants) how immediately would the effects on global warming been noticed?"
] | [
false
] | null | [
"It could actually take a very long time for temperatures to drop to pre-industrial levels, and this is the most worrisome part of global warming. The reason is that the temperature rise driven by increased CO",
" levels is not just limited to the stronger retention of thermal radiation by the greenhouse effect. ... | [
"its what climate does and has been doing for billions of years.",
"This makes it sound like the last 100 years of warming are not caused by humans, which is certainly not the case.",
"our best climate models are based on, typically, four variables for which static numbers are used to simulate.",
"Really? Whi... | [
"its what climate does and has been doing for billions of years.",
"This makes it sound like the last 100 years of warming are not caused by humans, which is certainly not the case.",
"our best climate models are based on, typically, four variables for which static numbers are used to simulate.",
"Really? Whi... |
[
"Are there other animals with any form of \"agriculture\", \"livestock\", or generally tending to what will eventually be their food before eating it?"
] | [
false
] | I'm not expecting "Babe the Farmer-Pig" or anything, but I could imagine, say, a fox that exists which permits a few scavenging rodents to finish his scraps until the day he eventually eats them, too. Perhaps some sort of fish or turtle or crab that maintains a "garden" of algae on it's body to be eaten? Anything tha... | [
"http://www.bbc.com/earth/story/20150105-animals-that-grow-their-own-food"
] | [
"Some species of ",
"Ants herd aphids",
"."
] | [
"Leaf-cutter ants maintain underground fungus farms fed on the leaf fragments that they collect. Other ant species guard and 'farm' aphids and collect their sugar-rich exudates."
] |
[
"[Physics] Why are we so 100% sure that the speed of light is the fastest any object can travel?"
] | [
false
] | I mean, we're more willing to say that time itself speeds up or slows down instead of having light move faster than 300 million m/s. | [
"Three lines of arguments:"
] | [
"No, it isn't specific of QFT. You can get the idea by looking at a pendulum. Its oscillation period doesn't depend on the amplitude of the oscillation: if you release a pendulum from its maximum height, its period will be the same as if you release it half that height. The period depends only of its mass and lengt... | [
"Can you explain the concept of a propagation limit? This is the first I've heard of it.",
"Is it something specific to QFT?"
] |
[
"If we have commensal bacteria in our guts that make a living by digesting our food, and whose composition can change based on our diets, doesn't this mean that the calorie in, calorie out model of nutrition is necessarily wrong?"
] | [
false
] | [deleted] | [
"The bacteria in your stomach ",
" you extract more calories out of your food. So yes in essence the calorie in, calorie out model is not entirely accurate. But then again you can't easily calculate the exact number of calories in a given food (the number listed on the box is likely just an average). Also, you ca... | [
"Calorie-in/calorie-out is a good, but over-simplistic rule of thumb. Regardless of the utility of the model, the presence of gut bacteria doesn't affect the calculus because your gut isn't considered \"in\" you. The entirety of the alimentary tract is considered outside of the body, so whatever the gut bacteria ar... | [
"Just because a model is wrong doesn't mean it isn't useful. Most models are wrong, really. The goal when creating a model is to decide which variables in the system you are studying are important and which ones aren't and then leave out all the factors that can be safely ignored for your desired degree of precisio... |
[
"What happens to metal compounds when they are heat-treated (tempered)?"
] | [
false
] | The chemical composition doesn't change, I'm assuming. So what makes the metal "stronger"? I saw a video of someone making a knife and they tempered it in a kiln, then alternated cold and hot cycles. | [
"Metals deform through the movement of ",
"dislocations",
" through the crystal structure. The atoms are packed tightly together as if they were hard spheres; attractive forces hold them together. If you wanted to move an entire plane of atoms in the crystal structure past the adjacent plane all at once, this... | [
"Great post. ",
"I would only add here that martensite in steels actually has the same crystal structure as ferrite- a BCC structure. Extra carbon distorts the crystal lattice tetragonally, to give a Body Centered Tetragonal BCT structure. When fully tempered, the carbon diffuses out of the structure, so that ... | [
"Metallurgy is close to black magic.",
"One thing that changes is the crystal or micro structure of the metal.",
"http://en.wikipedia.org/wiki/Tempering_%28metallurgy%29#Quenched-steel",
"Another popular process is case hardening where stuff gets added at the surface of the metal.",
"http://en.wikipedia.org... |
[
"How come some people faint from seeing blood?"
] | [
false
] | null | [
"Welcome to ",
"r/AskScience",
"! Check out our ",
"new",
" posts.",
" Please consider the following guidelines to help us maintain this goal.",
"read our updated and expanded guidelines"
] | [
"I suppose you can identify this blood-fainting gene? I'd settle for any published scientific evidence that corroborates your theory."
] | [
"Just found this article that may shine some light on the subject.",
"http://bodyodd.msnbc.msn.com/_news/2010/09/01/5022344-why-some-people-faint-at-the-sight-of-blood"
] |
[
"How does chloroform penetrate blood-brain barrier when it's hydrophilic ?"
] | [
false
] | null | [
"Even heptane can be 'mixed with water to some extent'. You've answered your own question. It isn't hydrophilic to the point that it can't pass through membranes. Lipids easily dissolve in chloroform."
] | [
"Chloroform is not hydrophilic. It isn't miscible with water."
] | [
"It's actually partially hydrophilic. It's true it isn't miscible with water but it can be mixed with water to some extent. "
] |
[
"If the universe ia expanding what is it expanding into?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"You question is either commonly occurring or has been recently posted on ",
"/r/AskScience",
". It may also be answerable using a Google or Wikipedia search.",
"To check for previous similar posts... | [
"Pleas send link to where this has been asked before. Thank you :) "
] | [
"The FAQ can be found in the sidebar."
] |
[
"Is there any air in-between our internal organs and skin, or some sort of fluid?"
] | [
false
] | And what happens to any air that's introduced during surgery? | [
"There is a fluid that exists inside of your body cavity (",
"coelom",
") but mostly there is fat, muscles, bones and peritoneum membrane that holds your organs together."
] | [
"There is no air in the abdomen outside the intestines. If there is air in the abdomen it's usually due to a surgical emergency like perforated bowel or trauma. Air in the abdomen after surgery is absorbed into the surrounding tissues."
] | [
"This. We're pretty much vacuum packed."
] |
[
"Why do micro-interactions between qubits not \"collapse\" the wave functions (under Copenhagen interpretation) when things like heat and sound can?"
] | [
false
] | I've been trying to find what it means to be an "observer" or something that "collapses" a wave function (those things currently mean the same thing to me). Why do small things like applying a Hadamard gate not collapse the superposition but exposing it to light or sound do? Where is the cutoff? Why is the cutoff? ... | [
"What you want from a quantum computer is coherence. Whenever a quantum state interacts with the environment (i.e. becomes entangled with it), it decoheres. A fully isolated system would never decohere, but you could also never measure anything. So what you want to have in reality, is a system that is isolated as m... | [
"Oh, I see. I assumed you had some prior knowledge in the field since you asked about Hadamard gates specifically. Let's start with a single qubit. An electron in a trap, for example. Let's say you prepare it in a state where it is equally probably spin up and spin down along the z direction. Unless you measure it,... | [
"Oh, I see. I assumed you had some prior knowledge in the field since you asked about Hadamard gates specifically. Let's start with a single qubit. An electron in a trap, for example. Let's say you prepare it in a state where it is equally probably spin up and spin down along the z direction. Unless you measure it,... |
[
"Why does most (if not all) life use phosphoanhydride bonds (ATP) as energy storage/currency when Phosphorous is limited in the environment?"
] | [
false
] | Is there any advantage to ATP and other phosphoanhydride bonds that seem to do most of the heavy lifting in the cells that other molecules just cannot do at all? It would seem that other kind of energy currency would compete at all if there were comparable efficiencies and traits. | [
"Given that nucleoside triphosphates are the building blocks of DNA and RNA, they are positively ancient and have been around pretty much since the beginning of life. The whole system kinda got locked in in that early stage. Phosphorus might have been more abundant back then and it never became so scarce so as to p... | [
"It absolutely does pose a problem for many plants and algeae. But as you say, they're locked in to using RNA/DNA now."
] | [
"In certain locations, sure. But looking at it globally, the total amount of plant biomass doesn't exactly suggest a severe problem."
] |
[
"Could there be an object that casts shadow but is not visible ?"
] | [
false
] | null | [
"Technically, a shadow is an area where direct light from a light source cannot reach due to obstruction by an object. So, anything that blocks visible light and creates a shadow would also have to be visible.",
"However, in the spirit of your question, it is possible to use a lens (while not completely invisibl... | [
"A similar example comes from schlieren. ",
"http://en.wikipedia.org/wiki/Schlieren",
"Have you ever seen waves of heat cast a shadow? This is because the hot air has a different density and index of refraction than cooler air, bending the light on the way through. It can be possible to have the heat waves (or ... | [
"It is similar. Air near road is hotter than air above it so air near road has higher index of refraction allowing you to see reflection of sky when looking at it from low angle.",
"http://en.wikipedia.org/wiki/Total_internal_reflection"
] |
[
"If we have 100% solar power production at home is there a point to using AC other than appliances being made for AC?"
] | [
false
] | null | [
"Pretty sure Edison was promoting DC and started a smear campaign against Tesla's AC - and lost."
] | [
"Nowadays the transformation of arbitrary electrical energy sources into an arbitrary other isn't an issue anymore due to high power electronics like IGBTs. Basically any source can be rectified and smoothened to a nearly perfect DC, which in return gets chopped, upscaled and shaped to any wanted form.",
"Therefo... | [
"Firstly, no it's not. AC and DC pose pretty much the same danger, they will both kill a human around identical voltage in the grand scheme of things. AC is slightly more harmful to the heart, however DC is a lot more dangerous for starting fires and more troublesome for breakers as low voltage DC arcs self sustain... |
[
"Gambling question here... How does \"The Gamblers Fallacy\" relate to the saying \"Always walk away when you're ahead\"? Doesn't it not matter when you walk away since the overall slope of winnings/time a negative?"
] | [
false
] | I used to live in Lake Tahoe and I would play video poker (Jacks or Better) all the time. I read a book on it and learned basic strategy which keeps the player around a 97% return. In Nevada casinos (I'm in California now) they can give you free drinks and "comps" like show tickets, free rooms, and meal vouchers, if yo... | [
"The Gambler's Fallacy refers to the belief that (for example) a long string of winning will make it more likely that the next result is a loss. This is incorrect if the games are independent.",
"Another effect, which is real and often confused with the above, is regression toward the mean. This refers to the ten... | [
"If the game works like a one-dimensional random walk, you will always end up ahead at some point, with probability one, but only if you have an infinite amount of credit to gamble with. Which, I daresay, you don't have.",
"I'd like to add that, for a ",
" random walk you are not guaranteed to end up ahead at s... | [
"If the game is rigged against you, which casino games are, then you are always better off quitting, whether you are ahead or not. In either case you are expected to simply lose more. If you have a loss and want to wait until you are ahead, then you run the risk of going broke.",
"Gambling in a casino is generall... |
[
"Would it be possible for a black hole to approach our solar system undetected?"
] | [
false
] | Could the first sign of it be it's effects on the planet's orbits, or is there no way it could get that close undetected? | [
"Is there any mechanism for creation of small black holes? Is there any reason to believe they even exist?"
] | [
"[I'm not an expert]",
"I believe we would be able to see a ",
"gravitational lensing effect",
", as the black hole's gravity bends light around it, distorting our view of the stars behind it."
] | [
"A black hole that size would take significantly longer than the age of the universe to evaporate, and so a primordial black hole could be this size (theoretically any size, in fact)."
] |
[
"Crosspost from askreddit: Say you have some sort of speed-of-sound reflexes. Is it possible to slap a bullet fired at you out of the way without harm?"
] | [
false
] | [deleted] | [
"I assume you'd try to hit the side of the bullet instead of the pointy. According to google, bullets rotate at 3000 rotations/second. With a diameter of 1 cm, that's about 54 km/h, which I don't think is enough to give your skin a friction burn (you could totally touch the side of a car going that fast).",
"Acco... | [
"It all depends on the bullet. If you were shot with a supersonic bullet, then no, you'd get shot."
] | [
"umm given the speed of sound ~1125 fps and the muzzle velocity of most guns, you would be shot before you heard the sound of the gunfire. If someone fired a weapon from say 100 feet away the sound would reach you in .08 seconds where the bullet reaches you in .03 seconds. Given human reaction times of 200 ms or so... |
[
"What happens to our brain when we find something funny? Why do we laugh? And why is it that minor mishaps like slipping off the floor, falling off a slide, etc. considered funny to a lot of people?"
] | [
false
] | null | [
"Here is a fairly good overview of current thinking",
"Many think we laugh at minor mishaps as a signal to others in the group that the person is okay and we don't need to take emergency action. It also helps the person who just experienced the mishap, as they get the outside signal that it wasn't a big deal or c... | [
"You should read the fiction novel \" Stranger in a Strange Land \" by Robert Heinlein.",
"It has some interesting philosophical ideas about why we laugh. :)"
] | [
"Because the football hit the man right in the groin LOL!"
] |
[
"Would cooking in a tall stock pot increase the boiling point (and thus cooking temperature) at the bottom of the pot due to the water pressure?"
] | [
false
] | I do realize that the cooking temperature at the bottom of a stock pot would also be hotter due to the fact that it gets heated from the bottom (especially if what you are cooking is thick). | [
"Yea, the effect will be weak, but it will be there. The hydrostatic pressure in a column of fluid on Earth can be estimates as pgh, where p is the density, g is Earth's gravity, and h is the height. So let's take a slightly exaggerated example and say the stock pot is 1m in height. Then plugging in the numbers for... | [
"You aren't going to have one of those in your typical home kitchen.",
"Also, you want to not let the temperature of a beer mash get above 170F to prevent bad tasting compounds in the grain husk from leeching into the wort, so the not so insignificant boiling point elevation simply isn't realized."
] | [
"What about huge vats they cook mash for beer in? Those can be 10s of meters tall."
] |
[
"Will cooling a piece of plastic increase its rigidity?"
] | [
false
] | Since getting it hot has the opposite effect (melting), if I stick a piece of plastic in the freezer will this make it more rigid? | [
"Yes it does. If you have access to a suitable piece of plastic, why don't you stick it in the freezer for a while and see for yourself? You will have to be fast though, plastics tend to warm up quickly (low heat capacity) so if you wait too long you'll feel it return to room-temperature elasticity quickly.",
"Th... | [
"Yes. Every polymer (all plastics are polymers iirc) has a T_g (glass temperature), which is the point at which the polymeric chains in ths amorphous regions (more responsible for the rubber, flimsy nature of some polymers) gain a lot of rotational mobility. Every plastic that is very rubber/bendable at room temper... | [
"I even had a piece of Tygon tubing explode, like tempered glass, when I rapped it on the table. The rapid cooling caused the same stresses in the plastic as occurs in glass that is rapidly cooled."
] |
[
"What is happening physiologically (in the lungs, alveoli, and general airway) when we cough?"
] | [
false
] | null | [
"Coughing is a response to the body detecting solids or liquids in the lower respiratory tract (trachea and below). While we can cough voluntarily, and to some extent suppress an urge to cough, a sufficiently strong stimulus will cause reflexive coughing that is impossible to suppress voluntarily. ",
"When coughi... | [
"Diaphragm, abdominal muscles, and intercostal muscles. The basic description above is correct, however the coughing reflex is stimulated by activation of J fibers in the lining of the airways, rather than detection of solids or liquids. Anything that irritates those nerves will cause cough."
] | [
"“When coughing, you close your vocal cords, then contract your intercostal muscles to build up pressure in your airways. You then open your vocal cords suddenly to quickly exhale, relying on the force of the moving air to blow out the offending agent.”",
"This is what I was looking for! So just to clarify, the p... |
[
"Why do those with Down syndrome have similarly shaped faces?"
] | [
false
] | While most faces are still unique in some way, those with Down Syndrome can be recognizable due to smaller ears, flatter face, almond-shaped eyes, and flatter nose. With all of the variations of facial features, why does Down Syndrome give even those who have a different cultural background very similar facial features... | [
"The best answer anybody can give is that some gene (or most likely genes) on chromosome 21 is responsible. We don't have a specific answer to the question yet.",
"One known factor, however, that almost certainly plays a role is the ",
"overexpression of a gene associated with collagen.",
" Collagen plays a... | [
"This is the correct response. Trisomy-21 reduces sensitivity of neural crest to the mitotic effects of hedgehog signaling. Trisomy-21 reduced the amount of proliferation of neural crest cells, which leads to the characteristic facial phenotype. It also tends to be associated with other neurocristopathies, such as ... | [
"Humans have 46 chromosomes so an additional chromosome equates to roughly a 2% difference from the norm.",
"Tiny nitpick: chromosome 21 is the smallest human chromosome so one copy of it only accounts for about 0.7% of the human genome."
] |
[
"Can someone in mid Indiana, go outside, look up, take a picture of the giant ring around the moon. What the hell is that?"
] | [
false
] | [deleted] | [
"Perhaps you are looking at a ",
"22-degree halo",
" around the moon? They are formed by ",
"randomly oriented ice crystals",
" in thin clouds (usually high up in the sky) refracting light from the moon at approximately a 22-degree angle. ",
"They often form around the sun too",
"."
] | [
"This is a very common misconception. A 22-degree halo is ",
" the same as a \"sun dog\". A sun dog (also known as a parhelion, meaning \"next to the sun\") is a bright spot (sometimes rainbow colored) 22 degrees to the right and/or left of the sun. A 22-degree halo is a circle around the sun. These two phenomena... | [
"that's it, thanks."
] |
[
"Could we detect strong force waves and weak force waves just like we detect gravity waves and electromagnetic waves?"
] | [
false
] | null | [
"There can't be \"strong waves\" or \"weak waves\". Just like EM waves are coherent states of photons, and gravitational waves are coherent states of gravitons, your strong waves or weak waves would be coherent states of gluons or W/Z bosons.",
"However, gluons don't really exist. That is, there is a gluon field,... | [
"So if there was such a thing as an actual gluon, which is coloured, you could change reference frame to get it to an arbitrarily low energy (you can do this only because the gluon is massless). As the energy is very low, confinement applies and you get a contradiction.",
"It took me a minute to figure out what y... | [
"Yep. Any massive particle would have a rest energy associated with it, which would stop you from reducing the energy arbitrarily. With a massless particle, whose energy is related only to its frequency, you can theoretically redshift it down as far as you want."
] |
[
"How do we know photons have no mass? They can exert force, their trajectory is bent by massive objects, and they fail to travel at an infinitely fast (or slow) pace from our perspective."
] | [
false
] | null | [
"You can always be skeptical about whether a photon has mass or not, and look at what experiments show. You can set up an experiment to measure a photon's mass (for example by looking for deviations from Coulomb's law) and ask the question \"given that we didn't detect any mass for the photon and we know how sensit... | [
"None of those things are inconsistent with masslessness.",
"Just to elaborate on that:",
"In fact if they were moving infinitely fast that would require Lorentz violations. Photons moving at the speed of light is absolutely a required consequence of them being massless in a lorentz invariant universe.",
"Gra... | [
"No. Light does not have \"zero energy\" because its mass is zero. Light does have momentum, and no, the equation p = mv isn't applicable to light.",
"Please refer to the ",
"/r/askscience guidelines for answering questions",
". It seems you are unfamiliar with a number of topics you've commented on - or at t... |
[
"In oil/gas drilling, how is torque applied effectively to the drill bit a mile or more below the surface? Is there a significant spring effect on the shank?"
] | [
false
] | It seems to me that it might take many rotations at the surface to start the bit spinning against the rock, and that the extremely long shank of the drill gets twisted up somewhat. I probably have some bad assumptions. | [
"Your assumptions are correct- the amount of twist in the shaft is proportional to it's length and the torque input. For oil drilling shafts that are many miles long the number of turns in the shaft is quite high, can be in the tens to hundreds of turns depending on how long the shaft is. Crazy to think about- bu... | [
"The diameter (girth) of the shaft experiences a shear stress of Sst at its outer surface according to the equation Sst=(T*r/J) where T is the torque applied, r is the radius, and J is the shaft's polar moment of inertia. As long as the material of the shaft can sustain the applied stress it will hold up. So the ... | [
"You are correct, however unlike in drilling through wood, the weight on bit (wob) is very carefully controlled to prevent it digging into the rock too hard, which can cause torque effects (stick slip) on the drill pipe.",
"Where the drill bit meets the rock it's more like a chipping away rather than a drilling p... |
[
"If the center of the earth were to suddenly explode for some reason, would the surface be obliterated as it went through the atmosphere, or would it just be shoved out into space?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"guidelines.",
"If you disagree with this decision, please send a ",
"message to the moderators."
] | [
"Wow, that's a fucking stupid rule. Speculation and fun not allowed, huh? "
] | [
"We try to guaranty some level of scientific accuracy. We have found that overly speculative posts promote answers that are at best educated guesses or more often than not complete non-sense. "
] |
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