title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Guitar question: Why do the harmonics on the 5th fret and the 17th fret have the same exact pitch?"
] | [
false
] | [deleted] | [
"Pinch harmonics (where you put your finger slightly on the string) are created by cancelling out the fundamental frequency of the string so that the dominant harmonic frequency at that location takes its place. This is done by putting your finger at one of the harmonic frequency's \"nodes\", seen ",
"here",
"Y... | [
"(Gets guitar...) They don't. The 5th fret harmonic is the same as the 24th fret harmonic. The 24th fret harmonic is the same as playing a note on the 24th fret normally, and is 3 times the frequency of the natural 5th fret note. 3 times the frequency translates to an octave and a 5th or 19 frets, and 5+19=24.",
... | [
"I made a little drawing to help illustrate what I'm talking about",
"These are drawings of a picked note, a higher picked note, the 5th harmonic, and the 17th harmonic.",
"Remember, the pitch of the note is determined by the frequency of the wave created by the string when you pick it. When you just fret a not... |
[
"Between foam, liquid, or bar, what is the best type of soap for handwashing?"
] | [
false
] | null | [
"Bar soap.",
"Further, antibacterial soap of any kind is ",
"raising concerns",
"00723-0.pdf) as a possible contributor to the spike in resistant bacteria.",
"Good old naturally derived bar soap doesn't just kill germs; it sucks them into it's gooeyness, then repels water, so you can rinse all the bad germs... | [
"I prefer ",
"this one",
" because it includes interesting information about ",
" soap works, why it doesn't need to be \"antibacterial,\" and why simply washing your hands is more effective than using hand sanitizer. ",
"Plus before he was made to edit it, it had a funny joke at the end."
] | [
"I prefer ",
"this one",
" because it includes interesting information about ",
" soap works, why it doesn't need to be \"antibacterial,\" and why simply washing your hands is more effective than using hand sanitizer. ",
"Plus before he was made to edit it, it had a funny joke at the end."
] |
[
"What is the most recent case of natural selection introducing a new widespread trait in any organism?"
] | [
false
] | I'm particularly interested to know if there's any in humans, but otherwise any organism. | [
"Definitely not the 'most' recent, but ",
"some elephant populations are increasingly being born tusk-less.",
"Historically, an elephant's tusks were ",
"a mechanism for digging and fighting",
" and an elephant with longer and stringer tusks would have a significant advantage. However, with the current high... | [
"Antibiotic resistance in various bacterial pathogens, such as ",
"MRSA",
" and ",
"MDR-TB",
" is the obvious example.",
"White nose syndrome in bats and chytridiomycosis in amphibians are also both driving selection within some affected populations (although they're also driving high rates of extinction ... | [
"There's also the ",
"famous example",
" of a moth in the U.K. with light- and dark-colored phases. The dark phase became more common in sooty industrial areas because it was better camouflage, while the original light-colored phase remained common in cleaner more rural areas."
] |
[
"Why does drinking water get rid of the stabbing pain in my heart?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"medical advice",
"/r/AskScience",
"Please see our ",
"guidelines.",
"If you disagree with this decision, please send a message to the moderators."
] | [
"This is also a question based on an personal or isolated event, which is against our guidelines: ",
"https://www.reddit.com/r/askscience/wiki/quickstart/askingquestions"
] | [
"This is also a question based on an personal or isolated event, which is against our guidelines: ",
"https://www.reddit.com/r/askscience/wiki/quickstart/askingquestions"
] |
[
"Would it be possible to have an Earth sized object composed completely of water? If so, would the core be a type of exotic ice?"
] | [
false
] | null | [
"If you had an earth-sized mass of water, its core wouldn't be composed of the same ice you see regularly. There are a variety of named structures of ice, but at high pressures it's mainly ice VII, VIII, X and XI. Beyond these, there are also amorphous ices of various densities (interestingly, not just one amorphou... | [
"Ice is a solid form of water, and its molecular structure can be amorphous (see LDA/HDA/VHDA ice) or crystalline (regular repeated units). Ice VII, VIII, X and XI fall under the latter: They are solid forms of water with different crystal structures. Look at ",
"Martin Chaplin's website",
" for pictures of the... | [
"Generally you can synthesize them in a lab, but the temperatures and pressures required can be, shall we say, ",
" for humans. You could probably see it through a viewing glass. As for what you'd see, it would depend on which structure you're considering. I can't say for sure since I'm on the simulation end of t... |
[
"At what point does a dialect become a language?"
] | [
false
] | null | [
"You're getting a lot of comments here but no one with linguistics flair is leaving any, so let me offer the view from within the discipline, as a practicing linguist who works heavily in dialectology and doing exactly the kind or work where this is most applicable:",
" None. It is not a linguistic reality that t... | [
"It's not ",
" a bad way to describe it, and one might still say \"now they're different languages\". It's just not a scientific or objective way to describe it. ",
"Mutual intelligibility has a number of significant problems ",
"which I mentioned in a comment here",
". So even if it were possible to consis... | [
"Max Weinreich said something similar: \"A language is a dialect with an army and navy\".",
"He said it in his native Yiddish, and for me it sounds exactly like German."
] |
[
"Does sound travel faster when it is raining compared to when it is not?"
] | [
false
] | Sound ravels faster in water than in air, so would sound travel faster when it is raining out than when it is not? (Or possibly simpler, would sound travel faster in a humid environment than an arid one?) | [
"For your first question (does rain increase sound speed), the answer is no.",
"The effect of rain on sound speed is relatively small, because the water is such a small component in the air. If it even did have an effect, it would actually be to ",
" the sound speed, because the water increases the effective ma... | [
"It depends on the wavelength of the sound. If the water droplets are small compared to a wavelength, the sound will just sort of...ignore them. If the droplets are large compared to a wavelength, they'll cause scattering. If the droplets are resonant, they'll strongly absorb the sound. Acoustic wavelengths range f... | [
"That's awesome. Thanks for answering a question I had been wondering about for a while."
] |
[
"I noticed that myself, my cat and my dog all yawn. Does this mean that we all share a common ancestor that yawned?"
] | [
false
] | I know that some evolutionary features can develop over and over independent of one another, but just how common is it? | [
"The last common ancestor between humans and carnivores was ",
"something like a shrew",
". Here is a youtube video of a shrew yawning: ",
"http://www.youtube.com/watch?v=rO6k1-NYJto"
] | [
"The last common ancestor between humans and carnivores was ",
"something like a shrew",
". Here is a youtube video of a shrew yawning: ",
"http://www.youtube.com/watch?v=rO6k1-NYJto"
] | [
"Convergent evolution is pretty common, so it's a bit hard to tell. I doubt the answer is conclusively known, since we can't tell if something yawned by looking at fossils or DNA. I would guess a single origin for mammals, though. "
] |
[
"Do dogs like/dislike or even perceive music?"
] | [
false
] | null | [
"Do they perceive it as organized sound?"
] | [
"The only animals I ever see that visibly perceives and enjoys music are birds. ",
"http://www.youtube.com/watch?v=N7IZmRnAo6s",
"Music must have an effect on other animals: ",
"http://www.washingtonpost.com/wp-dyn/content/article/2009/09/06/AR2009090601990.html",
"But it looks like birds enjoy music simil... | [
"Music is just certain types of sound. Dogs can certainly hear. So yes, they perceive music. Are you asking if they have a conception of it as any different than any other types of sound?"
] |
[
"Why is there no freshwater coral?"
] | [
false
] | I'm surprised to find out that with all the abundance of life underwater, there's still no freshwater coral. Can anyone explain why it would be so difficult for coral to live in fresh water? | [
"I'm NOT an expert here, I can only speculate, but maybe it has to do with the fact there are fewer dissolved ions in freshwater, and I know carbonate ions are needed for forming their rigid parts, their skeletal structure so to speak. (same goes for lots of shelled marine life).",
"Edit: pH may be a factor too... | [
"Speaking in ignorance; wouldn't that rule out freshwater clams and stuff too?"
] | [
"Obviously freshwater mollusks do exist. Maybe mollusks get their minerals from a different source than just the water around them (food?).",
"Again, I was just speculating.",
"Maybe it has to do with the fact that rivers are always unidirectional in flow, so corals can't ever evolve to settle there, they'd al... |
[
"Are there any animals which have benefited from human dominance of the planet?"
] | [
false
] | The only ones I can think of off the top of my head are city-dwelling pests such as rats and pigeons, but then again I know nothing about rat/pigeon population pre-civilization, so I could be wrong there. | [
"Dogs - or rather their wolf ancestors... In order to gain protection and a constant supply of food from the human communities at the time, the dog ancestors evolved to look less menacing (i.e. Increasingly cute), display loyalty and an offer of companionship. "
] | [
"If you're just looking at straight population counts, it could be said that domestic livestock, like cattle, pigs, sheep, chickens, etc. have benefited from human dominance. If you are considering quality as well as quantity of life in the term \"benefited,\" then it's harder to make that case. ",
"Certainly, as... | [
"Human dominance has caused \"benefits\" for a number of species through habitat transformation and invasive species introduction. As you mentioned, the destruction of native habitat and replacement by urban settings has allowed certain species to flourish (pigeons, rats, etc). Introduced exotics (rats, cane toads,... |
[
"Does higher brain plasticity also mean that you loose neural connections faster?"
] | [
false
] | null | [
"Not necessarily. Neural plasticity has to do with many more factors than just losing neural connections. For example, researchers have found that existing neural connections can be strengthened and weakened through processes called LTP and LDP. This does not necessarily mean the neural connection is lost completel... | [
"To expand, LTP and LTD are more long-term forms of plasticity because both these processes are involved in altering dendritic spine length and shapes (for example). Most plasticity is actually more short-term. Not all synapse LTP and LTD follows Hebbian law either, but there are always exceptions when talking abou... | [
"Great point! I made sure to include things other than LTP and LDP (my point on development of the neuromuscular junction as well as visual development). Synapses can be removed via spontaneous activity in the LGN as well as elsewhere prenatally (at least from what I remember) which kind of sort of follows a Hebbia... |
[
"Is it possible for one sun to orbit a larger sun?"
] | [
false
] | [deleted] | [
"Yes."
] | [
"Absolutely -- these are known as binary stars and they come in many different shapes and sizes. In fact, one type of supernova (type 1A) are caused by a white dwarf orbiting around a larger red giant star and accreting matter from it.",
"Interestingly, most star systems in our galaxy (and presumably other galaxi... | [
"Technically, no because they orbit a common barycenter. Then again, so does the Earth and the Moon. The barycenter between the two is about 1700 kilometers from the core, while still within the Earth itself. ",
"http://www.astronomycafe.net/qadir/q665.html"
] |
[
"Does earth's specific gravity facilitate life or do all the other variables dictate that life would have prospered anyway and adapted to almost whatever gravity our planet had.?"
] | [
false
] | i.e. is our gravity also in a Goldilocks zone? | [
"It's like a puddle that became sentient. The puddle says the hole it's in seems designed and perfect as it could not fit in any other hole. We all know that the puddle confotmed to the environment. This is how life works on earth, it grew to fit the environment. We can see radically different trends based on histo... | [
"Yes & No",
"Gravity doesn't directly impact the development of life, marine organisms largely disregard gravity. However, a certain amount of gravity is necessary to maintain an atmosphere (Mars lacks that minimum threshold and so lost it's atmosphere)",
"Once this minimum threshold is met, it's less importan... | [
"Mars has an atmosphere. It used to be thicker but didn’t lose it because lower gravity. It’s magnetic field diminished over time as the core cooled. The smaller magnetic field allowed solar winds to strip a lot of the atmosphere away. If it had no atmosphere we wouldn’t be able to land crafts/rovers with parachute... |
[
"Why does yellow exist on the light spectrum but not pink?"
] | [
false
] | Just read an article about how pink does not exist on the light spectrum, but our brain creates it to signify that it's "not green" Here is the link: . In essence it's saying that we only have red, green, and blue cones in our eyes, and when your red and blue cones fire but not green, your brain in a way "creates" purp... | [
"To understand, look at ",
"the color response curve of the 3 types of cones we have in our eyes",
". The x-axis is the wavelength of light going into the eye, and the y-axis is how strongly the cone \"fires\" based on that wavelength. Their peak response roughly correlates to blue, green and red, which is why ... | [
", non-real ones are ones which require a blending of different wavelengths",
"I think we will soon be in a position to perform the following lunatic experiment: edit a human genome with a transgene which encodes an inducible synthetic photopigment (an engineered opsin that responds at maybe 700). Let the human g... | [
"The fact that the brain can create a synthetic label we call \"pink\" for something that doesn't actually exist",
"Saying \"it doesn't exist\" isn't quite right, unless you mean that in the \"no colors exist\" sense, since color is your brain's lossy three-value model for an infinite number of frequency and inte... |
[
"Is it possible to not have a sense of humour?"
] | [
false
] | null | [
"Some diseases, such as Obsessive Compulsive Disorder, depression, (there are studies both ways) and Parkinson's Disease may reduce the sense of humour.",
"http://www.ncbi.nlm.nih.gov/pubmed/7886167",
"\n",
"http://www.ncbi.nlm.nih.gov/pubmed/22000944",
" "
] | [
"Please keep discussion:",
"Civil\n\nOn topic\n\nScientific (i.e. based on repeatable analysis published in a peer reviewed journal)\n",
"www.reddit.com/help/faqs/AskScience"
] | [
"Please keep discussion:",
"Civil\n\nOn topic\n\nScientific (i.e. based on repeatable analysis published in a peer reviewed journal)\n",
"www.reddit.com/help/faqs/AskScience"
] |
[
"AskScience AMA Series: My name is Thankful Cromartie, and I led the detection of the most massive neutron star ever (to date). Ask me anything!"
] | [
false
] | Hey AskScience! My name is , and I'm a graduate student at the University of Virginia Department of Astronomy and a Grote Reber Doctoral Fellow at the National Radio Astronomy Observatory in Charlottesville, VA. My research focuses on a special class of neutron stars called millisecond pulsars. Yesterday, a paper I led... | [
"I mean, I guess I’ll ask the obvious because I am super curious - what’s the story behind your name? Was it your name given at birth, or did you choose it?"
] | [
"Haha, I should have been more prepared for people to be so interested :) It’s actually an old family name! My full, legal name is Hannah Thankful Cromartie; my parents literally picked it off an old (1700s) family gravestone in eastern NC (where my family settled after leaving Scotland). In first grade, I started ... | [
"How smooth is a neutron star ? I read somewhere that a millimetre sized “starquake” on the surface would release deadly gamma rays. Have we detected such events ?"
] |
[
"No Electron Spin?"
] | [
false
] | [deleted] | [
"The \"spin\" of electrons, 1/2 and -1/2, is an intrinsic property of electrons. It does not describe the movement of electrons around the nucleus."
] | [
"First, you have to understand that \"spin\" is a bit of a poor name- the electron is not actually spinning, the electron has angular momentum which is in the direction that an electron would have if it were spinning. This \"spin\" is an intrinsic property of electrons (and in fact, of most matter). ",
"The fact ... | [
"Yes, I would agree. Electronic structure is central to chemistry. If electrons suddenly became bosons, all of chemistry as we recognize it would fall apart."
] |
[
"Why do small stars live much longer than big stars?"
] | [
false
] | null | [
"Bigger stars have more mass → more gravity → higher internal pressure → hotter → burn faster.",
"More precisely, ",
"the lifetime of a star on the main sequence scales roughly as M",
"Yes, bigger stars have more fuel, but they burn through it much faster."
] | [
"The quote is actually, “The flame that burns Twice as bright burns half as long.”\n-Lao Tzu, Te Tao Ching",
"Just modernized is all."
] | [
"Also, smaller stars have convection through which allows them to burn all of their hydrogen. Stars as big as the sun or larger do not burn all of their hydrogen fuel before going further up the element chain because they hydrogen can get to the core to fuse."
] |
[
"Assuming both volumes are equal, if I add cold water to hot water, and hot water to cold water, will they cool/heat at the same rate?"
] | [
false
] | null | [
"Semi-layman answer (I worked in a college fluid physics lab, but many years ago as a high school internship):",
"How are you adding the liquids to each other? Are you mixing the fluids together? If not, I would imagine they would mix at different rates (because of the complex fluid interactions, and the fact tha... | [
"If you mix them perfectly, then yes. ",
"Note that the density of water is somewhat complicated (",
"it is actually most dense at 4 degrees C",
"). At room temperature cool water is slightly less dense than warm water however. ",
"Basically, if you add cool water on top of warm water the system will be un... | [
"No problem, I was a bit hurried while typing it up, but the general concept is this:",
"1) Heat transfer is aided by large surface areas or mixing zones (this is why heat sinks have fins)",
"2) Diffrent geometric configurations can lead to diffrent rates of heat tranfer not only in the short run and the long r... |
[
"I've been reading about Portuguese man o' war, a colonial organism. Each species is completely dependent on each other. Could I be considered colonial composed of just single celled organisms?"
] | [
false
] | Man o' war: | [
"I think his analogy is not to humans and our bacteria, but to humans and our cells."
] | [
"A good place to start thinking about the differences between colonial organisms and multicellular organisms is their respective definitions. Colonies are defined as groups of organisms that closely associate but, if separated, are capable of survival on their own (I'm paraphrasing for the sake of brevity). Consi... | [
"A little clarification:",
"A man-o-war is one species, not many. It is many individuals or \"zoids\" attached together. It would be like getting a hundred people and duct tapping them together and say \"survive\". In the man-o-wars case each individual has a job: \"One of the polyps, a gas-filled bladder called ... |
[
"How are protein folding rates related to protein stability?"
] | [
false
] | [deleted] | [
"They are not at all related. Stability is a thermodynamic parameter, which means it is path-independent. Folding rates are kinetic parameters, which depend on many molecular details."
] | [
"The rate of protein folding and the stability of a folded protein are only linked indirectly. They both have to do with energy minimization and entropy maximization, but a protein might quickly fold into a local energy minimum that is ultimately less stable than its lower energy, global minimum. This is one major ... | [
"http://www.nature.com/nature/journal/v475/n7356/images_article/nature10317-f1.2.jpg",
"That figure is a good one showing what he is describing. To add on, a protein may quickly fold into a misfolded conformation, that is neither more or less stable (thermodynamically), but is in fact an aggregate which the cell ... |
[
"When is a tree considered dead and do trees die of old age?"
] | [
false
] | I'm know trees don't just fall over and die like animals do (atleast from old age) but some trees are still considered dead. I've read that some trees can live up to thousands of years. | [
"Heartwood in most trees is dead tissue that serves just a structural role. It can be rotted away without affecting the health of the tree, but not everybody understands this and they are likely to describe the tree as being dead."
] | [
"There is also the concept of \"negligible senescence\" where by some species do not appreciably age after reaching maturity. Giant tortoises are an example and continue to be able to reproduce their entire life. This is due to adaptations that reduce oxidative stress caused by free radical damage. ",
"Some flatw... | [
"There is also the concept of \"negligible senescence\" where by some species do not appreciably age after reaching maturity. Giant tortoises are an example and continue to be able to reproduce their entire life. This is due to adaptations that reduce oxidative stress caused by free radical damage. ",
"Some flatw... |
[
"Stupid question: Is dough considered a solid or a liquid?"
] | [
false
] | null | [
"The definition of liquid is that it must have a fixed volume but no fixed shape, so I think it is clear that dough (the one in your bread dough picture) is closer to solid than liquid because it has a fixed shape (i.e. it doesn't automatically take the shape of a container). ",
"Just because dough is very pliabl... | [
"Dough is probably best classified as a colloidial gel. The small starch granules and other particles are suspended in water within a polymeric matrix of proteins to form a gel. Think of Jello, is it a solid or liquid?"
] | [
"They are both amorphous materials, and don't fit perfectly well into solid or liquid."
] |
[
"How would this type of jaw surgery be performed? (Link in text)"
] | [
false
] | Xpost from : My mind is slightly blown. What is the nature of her condition, and how is it fixed so spectacularly? | [
"Severe overbites/underbites can be fixed with a ",
"bilateral sagittal split osteotomy",
" - basically they saw your jawbone off, move it, and screw it back on in the proper position. I had this done a couple years ago. "
] | [
"The recovery wasn't bad. I was in a lot of pain for the first couple days, but I was also on a lot of drugs :-) The surgery causes nerve trauma, so my entire jaw was almost completely numb. My mouth was rubber-banded shut using the brackets from my braces (this was all related to orthodontic treatment) so I was on... | [
"I too had this done. It's not that uncommon, I don't think. At least, I've met others. Mine was done in 1986, so it's not super new either. Lost like 40 pounds, it was awesome. My nerve damage is on the right, though.. interesting. Be careful if you get numbing shots at the dentist on that side.. my nerve is in a ... |
[
"Without the expanding force of fusion reactions, why don't gas giants get smaller?"
] | [
false
] | With stars, the outward pressure of fusion and the inward pressure of gravity eventually equalize, but gas giants don't have the outward pressure. Why don't they collapse in on themselves? | [
"There is an outward gas pressure. This is the same reason it is hard to compress a basketball down to the size of your palm. Gas pressure increases when the volume it occupies decreases (and temperature is held constant). Gravity acts to decrease the volume of the gas, and a balance is achieved when ",
"hydro... | [
"They do shrink. Once the gravitational pressure gets high enough, electron degeneracy causes them to shrink a bit. So they would appear smaller than they would below the limit, while being more massive."
] | [
"What ends up being important here is how much mass the body has to exert gravitational pressure with. If the pressure is such that the body never favors deuterium fusion, and thus never has thermonuclear fusion as a source of outward pressure, it's a gas giant. If the cloud of gas contracts sufficiently to support... |
[
"How Does Gravity Affect Single Particles?"
] | [
false
] | Does a single particle (like a hydrogen atom) in a vacuum fall like a macroscopic object in a relatively weak gravitational field (like the Earth's)? Or maybe does its position expectation value change like -(1/2)gt ? ELIundergrad if possible, and thanks! | [
"Gravity does affect individual particles. There have been some experiments to test how Newtonian gravity affects quantum systems (looking for interferences with cold neutrons passing through different gravitational potentials, etc.). I think Sakurai goes over the details in his QM book."
] | [
"We actually have a really good idea how things work in a weak gravitational field, thanks to Newton and Einstein. It's only when you get close to black holes when you need to include quantum gravity corrections, which are messy and less understood."
] | [
"Just to follow up on the \"How\" part of OP's question: We do not know. For all other forces we have this picture of force-mediating particles: photons, Z,W-bosons, and gluons for electromagnetic, weak, and strong force, respectively. This we have a very detailed understanding of (the Standard Model). For gravity ... |
[
"What makes one feature dominant and other recessive?"
] | [
false
] | I want to know why some features in genetics are dominant and can overcome this recessive ones, how they do this, what is the difference between them? | [
"This is a broad oversimplification, but one key difference here is loss of function vs gain of function. ",
"Take the ",
"Melanocortin 1 Receptor",
". This protein is a receptor that when triggered, most notably from skin damage through UV radiation, converts phaeomelanin, a reddish-yellow pigment responsibl... | [
"The problem with hair color is it's a polygenic trait, so simple Mendelian descriptions like that do not fully represent the situation.",
"Edit: ",
"Here",
" is a GWAS that found a bunch of sites involved in determination of hair color. It's particularly complex for various shades of blonde and brown."
] | [
"In the case of individuals with dual MC1R mutations in almost all cases the individual would have red hair, with some potential exception for albinism, etc.",
"That is not correct. They would more often have light brown hair. This is due to poor penetrance of many MC1R variants.",
"As the study above states:",... |
[
"I pull a tray of ice cubes from the freezer. Why are some of them opaque and some of them almost brilliantly clear?"
] | [
false
] | null | [
"The clear ones have higher transmittance than the opaque ones. This is because there are fewer regions of different materials within the ice, like air bubbles. Remember that light rays are scattered at the boundaries of materials (e.g. the air bubble- ice transition) due to the differing indices of refraction. So ... | [
"It has to do with how fast the water freezes. The ice cubes that froze quickly will be opaque, while the ice cubes that freeze slowly will be clear.",
"Here is why:\nFirst, if you look carefully you will see that the \"opaque\" part of the ice cube is actually many tiny bubbles. This is because there is gas (air... | [
"I can only think of one reason and that is morphology of the ice-crystals. Morphology describes the form of a crystal and the morphology describes the physical properties of your crystal. If the morphology is different, the physical properties are different. This fact is very important if you make solid (crystalli... |
[
"What physical differences are there between a marathon runner and a non-marathon runner (regular person) of roughly the same stature?"
] | [
false
] | It's much easier for me to understand the differences between a regular person and a strong person / heavy lifter. But what about the differences between a regular person and someone with a lot of endurance? My thoughts have been about: Better usage of the lungs?; more mitochondria? Less fat to carry?; more capillaries... | [
"I am assuming that you are referring to an exceptional endurance. There are two main types of muscle tissue in muscle and a third in cardiac muscle. The straited muscle also called slowtwitch and unstraited muscle called fast twitch. Fast twitch is what burst strength comes from. Slow is for endurance.",
"Goo... | [
"Just for clarification, there are some inaccuracies in what you've said, perhaps just a mistake.",
"Also, to answer OP well, a bit of background:",
"There are three types of muscle in the body: Skeletal, smooth, and cardiac muscle.",
"The muscle that propels us during exercise and under our voluntary contro... | [
"That makes great sense. If we had to compare a regular person (non-fit) with him again 12 months later ready for marathon, what would the differences be? Muscle composition as you mentioned. Anything else?"
] |
[
"Is there a limit to the number of pathogens our bodies can produce antibodies for?"
] | [
false
] | Since B cell lymphocytes are responsible for antibody creation, I assume the answer to this question is "the number of B cells in your body," but is there a theoretical limit to the number of distinct antibodies our bodies can create? | [
"First of all, B cells starting being unique, but when their services are needed, each unique cell multiplies. So total number of B cells is greater than the number of distinct antibodies you can produce.",
"Second, each distinct antibody can react to multiple antigens, so the total number of antigens you can res... | [
"Also, B cells are constantly produced from our bone marrows, so every day we get new ones with new specificities."
] | [
"Totally agree with everything you wrote, but I'm not sure I agree with the conclusion that there is a theoretical limit to how many pathogens/antigens we can create antibodies for. At least what I've learned as a medical student is that the diversity of the T/B-cell with V(D)J recombination is sufficient to always... |
[
"Why do energy drinks make me sleepy?"
] | [
false
] | Over the years I've drank every name brand energy drink on the market and not one has given me energy. In fact, most have made me sleepy. I'll feel a flutter in my chest for about 20 seconds... and then I feel as if I just finished working double-time. Is there a reason why my body would reject liquid energy and cause ... | [
"(LAYMAN) Perhaps it's this:",
"Paradoxical Reaction"
] | [
"Someone will have to elaborate but it is due to the insulin response due to the high sugar content."
] | [
"Nocebo effect",
" perhaps?",
"What I mean is, if the effect is immediate, then it is most likely psychological. You expect to feel tired, therefore you do. You may have created a subconscious association from a past experience when you were in a fatigued state and drank an energy drink.",
"If, on the other h... |
[
"Do elements in the Earth's core settle in homogeneous bands?"
] | [
false
] | I was wondering if elements in the molten portion of Earth's crust can be found together in layers like we see when you pour oil in a glass of water or if they are mixed up by a type of convection process. | [
"Yes! The interior of the Earth is differentiated, like a glass of oil and water. And it is due to the same principle of varying densities.",
"In the beginning, the solar system was a disk of gas and dust surrounding what would become the sun. This cloud was more or less homogenous (except that the gasses and oth... | [
"it was easy for the heavy metals like iron, gold, and uranium to sink down to the core. ",
"and yet, there is thought to be very little, if any uranium in the Earth's core at all. Despite being extremely dense, it is strongly a lithophile element, readily combining with silicates thus being concentrated in the m... | [
"Thank you!",
"The core itself is solid, having been \"pressure frozen,\"",
"Would that mean, to the best of our knowledge, the core is layered like a jaw breaker, or was it \"pressure frozen\" too fast for that to occur?"
] |
[
"Do fundamental particles exist in 16 dimensions, but we \"experience\" them in only 3? How can dimensions be folded up inside other ones?"
] | [
false
] | [deleted] | [
"I can't really comment on the 16 dimensional stuff since I'm not a string theorist, but I have a good analogy to understand the 'curled up dimensions'.",
"Consider a long string or cable. When you hold it in front of your eyes you can see it has multiple dimensions. There is the length of the string, and there ... | [
"Well, right now we have no evidence of these extra dimensions. String theory is still just a theory with no testable experimental predictions nor any experimental proof. So with that being said I can't really reference anything in the physical universe that we know possesses these curled up dimensions.",
"Theor... | [
"Well, right now we have no evidence of these extra dimensions. String theory is still just a theory with no testable experimental predictions nor any experimental proof. So with that being said I can't really reference anything in the physical universe that we know possesses these curled up dimensions.",
"Theor... |
[
"Does stellar wind cause dust and gas to collect in stable pockets in the interstices between stars?"
] | [
false
] | null | [
"Like millions (well, Re~10",
" - 10",
" ). The viscosity is very low.",
"It definitely behaves like a fluid on interstellar scales. The mean free path might be something like ~100 AU (~1 light-day), and the mean time between collisions might be years to hundreds of years, but in galactic astronomy we're deal... | [
"Stars do inflate bubbles of hot high-pressure moderate-density gas, but you don't get stable pockets in between the stars: these bubbles are still small compared to the size between stars. The Voyager I probe actually passed through the \"Heliopause\" in 2012, and passed out of the bubble inflated by the wind. The... | [
"Additionally, the interstellar gas is very turbulent",
"It’s dense enough that it still behaves as a fluid? What’s the Reynolds number for interstellar gas?"
] |
[
"Why is that photons can \"feel\" no time?"
] | [
false
] | null | [
"That's a really misleading way of wording it, but you used practically-audible finger-quotes, so I assume you get that.",
"Imagine two events in spacetime: one at which a photon is emitted, and one at which a photon is absorbed. We'll call the emission event ",
" and the absorption event ",
" We'll further s... | [
"If I could fix toasters, I'd have a working toaster right now."
] | [
"I tried. It just got brighter."
] |
[
"In a quote from the linked article from Nature “we describe the genomic profile and early transmission dynamics of Omicron, highlighting the rapid spread in regions with high levels of population immunity.” How does Omicron “spread” in area without high levels of population immunity?"
] | [
false
] | null | [
"In areas without high levels of immunity omicron will spread even more rapidly. The idea behind vaccinations was originally to stop the chain of transmission. We now realize that probably won’t happen since the community infection rate is very high. Instead we are hoping that vaccines will prevent severe illness. ... | [
"Isn't it also how this particular virus replicates in the upper airways where antibodies aren't readily available?"
] | [
"You have to remember there are different types of antibodies (t-helper cells, b-helper cells, neutralizing antibodies etc.). The vaccine was never going to provide sterilizing immunity like they do with measles. But they do afford some level of protection even with more replication happening in the upper airways. ... |
[
"Do multiple electrons exist during superposition?"
] | [
false
] | null | [
"So you're asking about a ",
" electron in a superposition state? Then yes, it's really in both places at the same time.",
"But it's still just one electron, not multiple."
] | [
"Thanks, that makes sense now!"
] | [
"What do you mean?"
] |
[
"How often do viruses mess with the adaptive immune system?"
] | [
false
] | My understanding is that essentially every virus capable of causing an infection in a human has some means of messing with the innate immune system so as not to immediately be wiped out by it. But how common is it for viruses to have non-structural proteins in their genome that are targeted at messing with the adaptiv... | [
"It’s mainly the large DNA viruses, like adenoviruses, herpesviruses, and pox viruses, that modify the adaptive immune system. Smaller viruses, including most of the RNA viruses, tend to focus on the innate immune system primarily. Presumably the DNA viruses have enough extra room in their relatively large genomes ... | [
"If a virus wants to replicate in the body for more than a week, it’ll have to interact with the adaptive immune system and the viruses that are able to develop ways to avoid detection will be more successful at getting spread. So I’d say lots.",
"One way is by not getting seen by T cells.\nOur healthy cells cons... | [
"That’s not adaptive immunity, which is limited to T and B cells."
] |
[
"Are fingerprints genetic at all? Would you be able to tell that someone is related to another person if their fingerprints are similar?"
] | [
false
] | null | [
"They're genetic, but they're also heavily influenced by environmental factors in the womb. ",
"For example, identical twins have different fingerprints. ",
"The foundation is genetic but it variations are introduced before birth. "
] | [
"Families often have similar overall fingerprint patterns such as loops or whorls but the small points of minutia that law enforcement uses to distinguish between fingerprints for identification are different.",
"There are also some trends in fingerprint patterns in ethnicity, but not enough to be useful in any w... | [
"A great deal of conditions (depression, diabetes, intelligence, etc.) have a genetic component and an environmental component so that many are not really well correlated with one alone. For instance, we know that if the mother has had previous male children, her future male children will be more likely to be gay."... |
[
"Why does our heart beat at the rate that it does?"
] | [
false
] | This question really is -- Why don't our bodies have a higher dilation of the veins as a default and beat around 20-30 BPM instead of the 60-80 BPM? Or alternatively, why don't our bodies have a higher constriction of the vasculature and beat at 140 BPM or so? Thanks in advance! | [
"Yes and no. It depends on the site of the body.",
"Many blockages, especially in the heart and in the larger arteries in the brain, are due to clots blocking flow.",
"In the kidney, constriction of the blood vessels can essentially starve the kidney of oxygen and kill it. Things like epinephrine (adrenaline)... | [
"Not a doctor, but IMHO if your vasculature was further constricted, wouldn't that increase mortality rates by increasing potential blockages?"
] | [
"First, arterioles, the smallest arteries with a muscular wall, are the main controllers of blood pressure. Veins mostly affect blood return to the heart",
"The quickest complete answer I can give:",
"Blood pressure is a function of the heart and of the vessels. Both are regulated by multiple systems to tight... |
[
"If one of the main reasons for inaccuracy in firearms is the effects of recoil on the shooter, why are gun barrels not vented on the top, so gas could be expelled upwards, fighting the jerk of recoil?"
] | [
false
] | null | [
"They are, it's called porting. But, most of the people who will pay to have their barrel ported are trapshooters and such, and most guns already have vents that porting might fuck up."
] | [
"I didn't know that, thanks"
] | [
"No problem brother, I'm a trapshooter myself, and my shoulder would be horribly bruised and I couldn't hit shit with anything longer than a 30\" barrel because of the upkick. Asked my coach about that and he had me meet a guy who ported my barrel for 50 dollars. Best addition ever to my gun."
] |
[
"Chemically, what makes high-efficiency detergents better/required for HE washing machines?"
] | [
false
] | From what I've read, the major difference in detergents between regular and high-efficiency is that HE detergents reduce suds to prevent pump failure in HE washing machines. Is this just due to the addition of an anti-foaming agent or is there more to it than that? | [
" \nBorax\nCitric Acid\nDiethylenetriamine Pentaacetate (Sodium Salt)",
"\nLiquitintTM Blue",
"\nAmylase\nMannanase\nPectinase\nProtease",
"\nDisodium Diaminostilbene Disulfonate",
"\nSodium Hydroxide",
"\nPolyethylene Glycol\nPolyethyleneimine Ethoxylate",
"\nBenzisothiazolinone",
"\nCalcium Formate\... | [
"Would it be possible that the HE just contains less water/filler?"
] | [
"Certainly, the ratios of ingredients are probably different, but how much would be guesswork with out a lot of analysis. Just based on the amount of material you add this may be the case, however, Front-load washers use a lot less water, so to have the same concentration of detergent in the water you'd expect to... |
[
"Why is coffee cup calorimetry constant pressure and bomb calorimetry is constant volume?"
] | [
false
] | Like the question asks, what pressure is being constant in a coffee cup calorimetry? The pressure inside the cup or the air pressure outside? Either way, why is the pressure not changing? Similarily, is the volume of the reaction chamber being referred to when we say constant pressure or is its the external insulating ... | [
"The coffee cup is not airtight, so the pressure is just atmospheric pressure. A bomb calorimeter is pressurized and tightly sealed so that the gas produced cannot expand, so the volume remains constant and the pressure inside goes up."
] | [
"Thank you for your help!"
] | [
"Like the question asks, what pressure is being constant in a coffee cup calorimetry? The pressure inside the cup or the air pressure outside?",
"Either way, why is the pressure not changing?",
"The pressure inside the cup is dictated by the air pressure outside the cup because there's a relatively large openin... |
[
"What is the name for the mixed particle that photons form when moving through a medium?"
] | [
false
] | So I know that the absorption/emission explanation for light slowing down in a medium is wrong, and I somewhat understand the other explanation. But for the life of me I can't recall what exactly the quasi-particle that is formed during the interaction is called. I've checked the FAQ on the subject, but the only names ... | [
"Polariton.",
"Also mentioned in the ",
"FAQ"
] | [
"It's a polariton under a certain set of assumptions. Though the term polariton has multiple definitions and takes different meaning depending on community. But really it's best in almost all cases to treat it classically using Maxwell's equations in a medium. Even in quantumy scenarios like modelling spectroscopy... | [
"Also, be sure not to confuse them with polarons."
] |
[
"Why is it that listening to music at a certain volume hurts my ears in a quiet room, but listening to it in an airplane at the same volume doesn't bother me at all?"
] | [
false
] | I'm just using music as an example. If I accidentally turn on music in my headphones at full volume in my room, I get a physical pain in my ear because of how loud it is. On an airplane, I need to play my music at full volume to even hear it, and it doesn't bother me at all. Why is this? Does the ambient noise make a d... | [
"In the airplane, you're probably protected by the middle ear's acoustic reflex. According to ",
" 3e, this mechanism is activated by sounds above 75 dB(SPL) and, within 60-120 ms, starts attenuating frequencies below 1kHz by 12-14 dB. There's more information at ",
"Wikipedia:Acoustic reflex",
", although th... | [
"3 responses and nobody mentioned the tensor tympani muscle? Aww, well let's check the wiki link on Acoustic reflex, I haven't heard of that specifically. Oh! ",
"When presented with a high-intensity sound stimulus, the stapedius and tensor tympani muscles of the ossicles contract. The stapedius pulls the stapes ... | [
"Does the acoustic reflex physically reduce damage? It seems like that is what the article says, but this is a foreign topic for me so I wasn't sure... Thanks!"
] |
[
"What Is In a Modern Day Cigarette and Why Is It So Bad For You?"
] | [
false
] | null | [
"A lot of carbon monoxide, hydrogen cyanide, carbon black, polyaromatic hydrocarbons, to name a few. All of these things are unhealthy to inhale.",
"EDIT: Source? Ran an IR on smoke of a cigarette."
] | [
"They don't put it in there. It's a by-product of the combustion. Hydrogen cyanide is a gas (in my climate at least), and would not keep in the cigarette."
] | [
"Why cyanide?!",
"How would that help the flavour? Or anything for that matter?"
] |
[
"How does adding energy to an e- move it to an orbital further from the nucleus?"
] | [
false
] | I understand that electrons in higher orbitals have higher potential energies, but I dont understand what it is that changes in an electron that having a higher energy moves it further from the nucleus. | [
"It is absolutely not the same! Electrons are nothing like satellites; that's a fiction told to people in order to avoid getting into quantum mechanics. If electrons were orbiting like satellites then they would radiate energy and quickly crash into the nucleus. Electron orbits are more like states of particular re... | [
"It is the same way that an object placed on top of a ladder has more potential energy. The nucleus and the electron attract each other just like a rock and the earth attract each other. (Except with electromagnetic force instead of gravitational)",
"Moving the electron to a higher orbital requires that some ener... | [
"Electrons are attracted to the nucleus by an inverse square law, like satellites are to the planet. Quantum physics makes electrons not be exactly like satellites, but they aren't nothing like satellites."
] |
[
"If the winter solstice is the shortest day of the year, why is it that the coldest days seem to be during January/February?"
] | [
false
] | Also, why is it so much colder 20 days before the March equinox (e.g. March 1) than 20 days after the September equinox (e.g. October 10)? This is all pertaining to the northern hemisphere, of course. Reposting this question since it didn't receive a response yesterday. | [
"It has to do with the daily energy budget: how much energy is incoming from the sun per day vs. how much energy is outgoing from the earth per day. The sun supplies a lot of energy (mostly in the form of visible light which gets absorbed by the ground) during part of the day, and the earth is continuously re-radia... | [
"I was going to say:",
"Think of warmth like money the sun deposits in a bank account, which always has money going out as well as coming in.",
"Sunlight reaching the ocean or land warms the Earth. But the warm ocean or land also give off heat, which escapes out into space as infrared energy. This is why it alm... | [
"Thanks. I wish I could find you all a chart that shows annual incoming and outgoing energy curves, but hopefully you can imagine it well enough.",
"Best I can do is show the ",
"incoming and outgoing energy as a function of latitude",
". With the annual change in seasons, the surplus area would oscillate suc... |
[
"Why do we hear static on speakers or headphones when we are about to get a phone call or text message?"
] | [
false
] | When my phone is near my speakers or headphones, I hear a series of static noises in quick succession of one another right before I receive a call/SMS, sort of sounds like a beep. Why does that happen? | [
"But why only during the connection procedure? Once you get the call there's not a sound. ",
"Is the initial connection much higher power, perhaps, and the transmitter and receiver drop to a low-power mode once they've established the parameters of the connection?"
] | [
"The circuit in your speaker acts as an antenna that picks up the signal and plays it out. "
] | [
"The receipt of a call or SMS causes the circuitry inside the phone to produce electrical noise, which is coupled into the speakers. If this happens with passive headphones that aren't plugged into the phone or anything electrically connected to it, your phone is throwing out extreme amounts of RFI. Crappy iPod d... |
[
"Are moths and butterflies able to cross breed like tigers and lions?"
] | [
false
] | I know that lions and tigers can make and produce sterile offspring. Do moths and butterflies have that same ability? They seems close enough genetically but what factors would limit them? | [
"I suspect you'll have to be more specific as there are thousands of species of moths and butterflies, which are an order, whereas lions and tigers are species within the same genus. ",
"If you mean if an arbitrary moth and an arbitrary butterfly, then almost certainly not. They diverged 56 million years ago, wit... | [
"All moths are equally distant from all butterflies and vice versa. They split from each other before splitting into the many species that exist today. It's similar to asking if there's some dog that's close enough to breed with some cat."
] | [
"There are ",
"moth x moth",
" and ",
"butterfly x butterfly",
" hybrids at least. Species boundaries are never that rigid.",
"For a very rough comparison, monarchs and peppered moths share an order the same way you and capuchin monkeys share an order if not more. 56 million years is a lot from the perspe... |
[
"Why does rotating a spaceship create artificial gravity?"
] | [
false
] | I understand the idea of angular momentum and centrifugal force, but I also understand (I think) how relativity factors into physics, and the aspect of artificial rotational gravity that I don't get is how we can say for sure that the spaceship is rotating and not everything else. If everything else were rotating, then... | [
"Short answer: Not everything is relative. Acceleration is absolute, and you can determine that the spaceship is spinning instead of the universe specifically because you can measure its centrifugal force. At every event in spacetime, there exists a special set of reference frames which are inertial (i.e. freely fa... | [
"What makes acceleration absolute, though?",
"The fact that an accelerometer (a mass on a spring) on board the spaceship will register it (by expanding in the direction away from the acceleration).",
"What happens if the universe only contains one wheel? Would there be any way to determine whether it's spinning... | [
"What makes acceleration absolute, though? If I am accelerating away from something, from my reference frame it seems that that thing is accelerating away from me.",
"Does it have something to do with the fact that an accelerating rocket is expending energy doing so?",
"What happens if the universe only contain... |
[
"How Did We Discover Bi-209 Is Radioactive?"
] | [
false
] | Given that its half-life is so ridiculously long, what led us to find out that Bismuth isn't actually stable? Did we "get lucky" and happen to witness some decay, or are there analytical ways to determine an element's radioactivity without needing to observe anything? If the latter is the case, what prompted us to do t... | [
"Are there analytical ways to determine an element's radioactivity without needing to observe anything",
"There are ways to roughly predict whether an element would be radioactive, but getting an actual quantitative result to any precision is not possible from first principles using theory, and even numerical met... | [
"https://en.wikipedia.org/wiki/Bismuth-209",
"Bismuth-209 was long thought to have the heaviest stable nucleus of any element, but in 2003, ",
" at the Institut d’Astrophysique Spatiale in Orsay, France, discovered that 209Bi undergoes alpha decay with a half-life of approximately 19 exayears ",
"https://pdfs... | [
"Mass of Bi-209 = 208.9803987 amu",
"Mass of alpha = 4.00260325415 amu",
"Mass of Tl-205 =204.9744275 amu (decay product)",
"208.9803987 - (4.00260325415+204.9744275) = +0.0033679 amu",
"Since the mass of the parent Bi-209 is heaver than the mass of the decay products, it is a reasonable assumption that the... |
[
"If the solubility of CO2 decreases as temperature increases, then why is global warming causing ocean acidification?"
] | [
false
] | I've read that the CO2 becomes less soluble in water the hotter it gets, but I've also read that the ocean is absorbing more CO2, causing its pH to decrease. Are both of these statements true? If so, how? | [
"For simple solutions, the relationship between the partial pressure of a gas and the concentration of it in a solvent is proportional, ",
"p = kc ",
"This is called Henry's law. k can be a function of temperature. For CO2, k becomes smaller at higher temperatures, so at the same partial pressure, less gas ca... | [
"The ocean is not yet saturated with CO2. As the partial pressure of CO2 in the atmosphere increases, more dissolves in the oceans. ",
"If the oceans were saturated, they would lose CO2 as they warmed. "
] | [
"There's a bit of chicken-and-egg going on here. The temperature rise is being driven by elevated atmospheric CO2 levels. It's the CO2 concentration in the atmosphere that's driving the increased concentration in the sea, not the temperature. Eventually, if the sea temperature rises enough, it'll start releasing... |
[
"How long was a day on Earth 300 million years ago?"
] | [
false
] | null | [
"Still exactly 1 day :)",
"But as compared to a different reference standard for time, such as an atomic clock, the earth used to spin a bit faster. The influence of the moon causes tidal braking of around 2.3 ms/century. So 300 million years ago, that would be around 2 hours. So it would be a 22 hour day instead... | [
"He said it was 22hrs instead of 24. So, 300,000,000 *22/24 = 275,000,000",
"Idk what that has to do with anything though. "
] | [
"The Earth was spinning faster, but what about its orbit around the sun? Was a year the same amount of time?"
] |
[
"I was just introduced to this 'miracle' product that frankly has set off red flags, but I don't have the background to dispute or verify the claims."
] | [
false
] | null | [
"What is the product called? Do you have any other information?"
] | [
"OK, this looks potentially legitimate (but probably not actually effective). Although the website calls the linkage \"saline\" which means salt, what they show is actually a \"silane\" which will indeed link a molecule to a surface through a stable, lasting bond. So that part is legit. The second part is based on ... | [
"And I am the one who asked for a link. Ooops. Sorry. What i mean is that the compound linked to the surface will have to physically contact a large part of a bacterial cell. That means the bacterium will have to be within about 0.01 micrometer or less of the modified surface to be affected because that's how long ... |
[
"Soap/shampoo can be any color but the suds are always white. Can someone explain?"
] | [
false
] | null | [
"They're diluted when used. The bubbles, being on the micron length scale, also scatter visible light making the foam look white. It's why milk is white and not transparent. For smaller dispersions of particles, bubbles or emulsions smaller wave lengths of light are scattered more intensely and so they can appear b... | [
"Not air bubbles but extremely tiny particles. They're so small, gravity doesn't really affect them in a solution so they can stay suspended sort of indefinitely.",
"But if you leave your milk in the fridge for a few weeks because you accidentally forgot to dump it before going on vacation, you can actually start... | [
"Milk is white because it is filled with microscopic air bubbles?"
] |
[
"In time dilation, time passes faster the further an observer is from a large center of gravity. So on the surface of the earth, time is faster than the center of the earth. Does this have any effects in geological time scales on different theories such as plate tectonics, continual drift, etc?"
] | [
false
] | [deleted] | [
"Actually, the gravitation in the center of earth is zero.",
"The acceleration in any direction due to gravity is zero at the center of the planet, but you are still within a gravity well, so clocks still run slower compared to someone outside that well."
] | [
"There is no such thing as \"real\" or \"normal\" time. Time dilation for one object can only be considered relative to the time perception of some other object. That's why it is called the theory of relativity."
] | [
"The time dilation due to Earth's gravity is about one part in 10e9. If no part of the Earth ever moved, then over the 4.5 billion year lifetime of the planet, the rocks at the very core are about 4 years \"older\" than the rocks at the surface.",
"This difference is so small that it has no effect on anything at ... |
[
"How fast could we get a spacecraft going with current tech?"
] | [
false
] | I know there are a lot of theoretical, untested drives out there, so for the sake of this, let's limit this to any technology that could actually make it's way into space and propel a spacecraft within the next 10 years. With the best available drive, and the hardest planetary sling-shotting we can muster, how fast cou... | [
"I don't believe there's a known answer for this. It comes down to what percentage of the space craft you are willing to use to devote to fuel. The higher the percentage, the faster you can go. The achievable speed is purely Newtonian. If you eject 50% of the mass, then you would be traveling at the same speed ... | [
"You're referring to a ",
"Bussard ramjet",
". Unfortunately, the drag and subsequent deceleration caused by gathering fuel exceeds the acceleration gained by expending said fuel. This nets out to deceleration, unfortunately. At least, these were the findings of Zubrin in and Andrews back in the 1980s (the a... | [
"Chemical rockets wouldn't be able to match even the most basic nuclear powered rocket. The energy released by chemical reactions per kilo of mass is too low. If money and safety were no concern, you could create a spacecraft using a number of experimental components. These have been built and tested in labs on Ear... |
[
"Energy loss of a bullet - free swinging target vs fixed"
] | [
false
] | Hi, An post led to question and it's follow-up comment. Summarised in essence ; a 50 caliber round failed to penetrate a free swinging steel plate at 200 yards. A question was raised about the difference if the target were fixed. A supposition was given that the transfer of energy was over such a short period that th... | [
"50 BMG is used in the video."
] | [
"Just adding that it would highly depend on the .50 cal used and what weapon it's fired from. Kinetic energy is proportional to velocity squared.",
"Examples: ",
"A .50 cal Hollow-point 325 grain Action Express round fired from a Desert Eagle pistol with a 6\" barrel will have a muzzle velocity of 398 m/s (1 66... | [
"It's still a big difference between different cartridges of 50 BMG. Regular cartridges are designed ",
" to pierce through targets, but to be absorbed by the tissue of the target. When firing at a steel plate a regular bullet scatters and much impact energy is lost.",
"The 50 BMG Armor Piercing round should pe... |
[
"Why have insects and reptiles more readily developed poisonous/venomous capabilities than mammals or birds?"
] | [
false
] | I understand that there are very few poisonous/venomous mammals and no venomous birds. Why have these species shunned a useful defensive technique? Is it that they were able to survive well enough without the need to use it? | [
"Most of evolution is pressure-based; if you have have nothing killing you...you don't need to adapt. Insects tend to be the food source for many different animals. As such, they are exposed to much more pressure to adapt protection. They also reproduce wayyy faster/more plentiful than mammals, which lends to m... | [
"no venomous birds",
"That's actually not true. The ",
"hooded pitohui",
" of Papa New Guinea is poisonous. ",
"Here's",
" a pretty cool video done by the guy who discovered it. He goes into detail about the toxic compounds they found."
] | [
"My most educated guess would be the size of the prey and has virtually nothing to do with defense since most venomous animals prefer to flee rather than bite. the reason it deals with the size of prey is that the smaller the organism, the faster it motabolizes making venom alot more applicable for hunting small pr... |
[
"Will flickering the lights (or turning them on and off really fast) actually cause a fire / short circuit?"
] | [
false
] | I remembering being told as a kid never to flick the lights on and off rapidly because it could cause a fire. My roomate just flickered the lights in my bedroom and now I'm typing this message. | [
"Nah, not really.",
"Flicking the light switch on and off rapidly has a number of effects, which I will try to deal with individually:",
"Remember that a dimmer is, in fact, just a \"glorified switch\" that turns the light on and off so quickly we cannot see it — and they do normally not cause fires, do they?"
... | [
"If you want to get entirely technical the light bulb is turning off 60 times per second anyways it happens so fast the filament stays heated (in incandescent) .So flipping it on and of wont really hurt the bulb,except maybe the electronic ones. The switch would be the main concern, that you may break something mec... | [
"Incandescent bulbs have much lower resistance when they are cold, as such a much higher current flows through them before the light appears. This can stress the wiring, the switch and the bulb causing something to fail. Comparing two scenarios where in one the bulb is just on and in the other you are flicking it o... |
[
"Why can't we think in \"dream time\" when we're awake?"
] | [
false
] | This morning a sound woke me up (almost instantly, in a second or two) in that time I had a dream that would take about 30sec-1 minute if it were playing on TV. | [
"Time doesn't pass any differently while you're dreaming or awake. You might perceive or remember it differently.\nMore info:\n",
"http://indianapublicmedia.org/amomentofscience/time-passes-dreams/"
] | [
"Thanks! I love askscience:)"
] | [
"1) Recall Bias. When you're awake, you're not experiencing the dream. You're just remembering what you can of the dream, leading to biases in perspective.",
"2) Perspective bias: We can 'think' faster if we want to: eg. I could speed up a video I saw earlier as I remembered it. I could also make up a story spann... |
[
"Are there gemstones on the moon?"
] | [
false
] | From my understanding, gemstones on Earth form from high pressure/temperature interactions of a variety of minerals, and in many cases water. I know the Moon used to be volcanic, and most theories describe it breaking off of Earth after a collision with a Mars-sized object, so I reckon it's made of more or less the s... | [
"The ",
"surficial geology of the moon",
" is relatively simple compared to Earth, the Lunar highlands are predominantly ",
"anorthosite",
" and the Lunar maria are predominantly ",
"basalt",
". On Earth, neither of these rock types are associated with common gem minerals (EDIT: unless you consider oliv... | [
"Considering the impact hypothesis, a large portion of the material that accreted to form the moon was ",
"molten",
", thus at least at the surface there is no material that is preserved 'solid bits of Earth', for lack of a better term."
] | [
"If the processes that form gems on earth are not present on the moon, could there be gems left from the origin of the moon's material makeup? The prevailing theory as I understand it is that the moon formed from a collision with the earth. Could there be gems formed on earth and launched into space to coalesce int... |
[
"What is the difference between Deep Learning and Artificial Intelligence?"
] | [
false
] | What is the difference between Artificial Intelligence vs Machine Learning vs Deep Learning? | [
"You can argue the toss a little about the exact definitions but I'd style it like this :",
"Artificial intelligence : See this link - ",
"https://www.reddit.com/r/askscience/wiki/computing/ai_definition",
"Machine Learning : the branch of computer science and (computational) statistics which deals with dev... | [
"Artificial intelligence : the branch of computer science which deals with making machines which display intelligence. One goal being a machine which displays human-like, general intelligence. Our current attempts make extensive use of machine learning algorithms because we can use these to make decisions and decis... | [
"Fair point, I should have left it styled as agent as I originally wrote, I'll just swap in your link."
] |
[
"Can someone explain how voltage and current have a phase difference in ac circuits containing inductors and/or capacitors?"
] | [
false
] | So a couple of things I don't understand: What is happening? In circuits that involve capacitors, I've learnt that current leads voltage. But how does that work? Does complex impedance have phase difference? I know that V=IZ, and if V doesn't have a phase difference (taking V as the starting reference point) and I does... | [
"It happens because there is some energy stored in the capacitors and inductors. ",
"For example, if we put a current through an inductor, the inductor will store energy as a magnetic field. If we stop the voltage source that gave the inductor its field, the inductor will try to maintain its current using the mag... | [
"For the purposes of this post I will be assuming all signals are sine waves and the voltage function has no phase offset. It makes things a little easier to talk about if we state from the outset that ",
"v(t)",
" at t=0 is our zero phase reference.",
"What is happening? In circuits that involve capacitors,... | [
"Sietis's answer is very good and probably better than what I can come up with.",
"If impedance has phase-like characteristics, does that mean it fluctuates like a wave?",
"In phasor form the impedance itself isn't changing when only using capacitors and inductors; the impedance of these components only depends... |
[
"If a huge and dense enough amount of coherent light was emitted, would it create a black hole traveling at the speed of light?"
] | [
false
] | [deleted] | [
"A system of photons all moving in the same direction has no invariant mass, so you can Lorentz-transform into a frame where they have arbitrarily small energy. And in such a frame, it's clear that they should not form a black hole.",
"And, a black hole has mass so it can never move at c.",
"But anyway, it's in... | [
"I'll take a stab at an estimate. The shortest pulsed laser system has ~ attosecond width, and I've worked with systems capable of 10s of femtosecond pulses, so lets assume a 1 fs laser pulse. Also assume that the lasers are firing from all directions inward, to approximate a spherical shell of light.",
"The inva... | [
"If you have an unlimited budget you could in theory make a black hole by piling up the money from that unlimited budget. Now all you need to do is make a currency out of photons and there you go."
] |
[
"Does it make a difference (to weight loss efforts) if you were to eat an extra 10,000 calories in one day, or an extra 1,000 a day for ten days?"
] | [
false
] | null | [
"“I never ate that much,” Phelps said. “It’s all a myth. I’ve never eaten that many calories.”",
"Said Phelps: “I wish. It’s too much though. It’s pretty much impossible.”\n",
"http://www.thebiglead.com/index.php/2012/05/11/michael-phelps-legendary-12000-calorie-a-day-diet-is-a-myth/"
] | [
"As a side note, it would be extremely difficult for most people to eat an extra 10,000 in one day above what they are normally used to. This would be the equivalent of eating 10 dozen eggs, or 12 sticks of butter, or 18 Big Macs. Many people would get sick and throw up before managing to consume that much extra fo... | [
"I watched a youtube video of a guy drinking 20,000+ calories of olive oil. Probably found it through Reddit. Wasn't a good idea, but clearly it can be done.",
"EDIT: Here's ",
"the video"
] |
[
"Can someone please explain why this is wrong to me? Someone is trying to show me \"proof\" that Earth is not round AND that Earth does not move. (link in the text)"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"\"Sorry, flache-erde.bplaced.net has been blocked due to to it being a suspected malware site. \"",
"If you disagree with this decision, please send a message to the moderators."
] | [
"I'm in the United States, on my work computer so I presume whatever site-blocking software my company uses picked up on it. ",
"But anyways critical thinking websites also encounter opposition though... :-) No wonder they get banned^",
"I'm sorry you feel that way. When I get home I'll try to remember to check... | [
"I'm in the United States, on my work computer so I presume whatever site-blocking software my company uses picked up on it. ",
"But anyways critical thinking websites also encounter opposition though... :-) No wonder they get banned^",
"I'm sorry you feel that way. When I get home I'll try to remember to check... |
[
"How would one calculate if striking a metal shell would deform it, penetrate it, or not deform it (in the context of striking armor with a weapon)?"
] | [
false
] | null | [
"This is not a straightforward thing to just calculate on paper. It's like asking whether a fall from a certain height will break a watermelon. It depends on too many factors (like how high is the fall, how elastic is the floor, what part of the watermelon hits first, and what's the overall shape and material prope... | [
"This is not a direct answer to your question, but in practice this question is answered through experimentation, not calculation. If you were implementing a high-level simulation or a game you could then use experimental values to determine the behavior of objects in the simulation.",
"Vehicle or structural armo... | [
"In Structural engineering, deflection is based on the support conditions, geometry of the material, the force, youngs modulous of the material. ",
"There's a relation for metals that stress/strain of the material will revert back to its original geometry. That relationship is the Youngs modulous. (E) = Stress/St... |
[
"I just started running. My friends insist I should run on my toes, not my heels because it's \"better\". Any science behind this?"
] | [
false
] | I get inconsistent answers when I ask why, ranging from the vague "It's more natural" to the nonsensical "that's what cats and dogs do". Running on my toes makes my arches ache, but I could just be an out of shape pansy. If it makes a difference, I generally run on treadmills. Thanks, science reddit! | [
"Just recently, in fact:",
"http://www.ncbi.nlm.nih.gov/m/pubmed/22217561/",
"The study looked at repetitive stress injuries in HS cross-country runners. Those that had forefoot strikes had lower injury rates versus heel strikers. ",
"This one:",
"http://www.ncbi.nlm.nih.gov/m/pubmed/22217565/",
"Found th... | [
"Toes? No. Balls of your feet, yes."
] | [
"Former DI Runner. I don't have time to find the references for you but here's what I've learned:",
"Running barefoot or in racing shoes (which don't have built up heels), top African distance runners tend to land on their forefoot or midfoot, allow the rest of the foot to come down, then push off their toes aga... |
[
"Can egg born animals have twins?"
] | [
false
] | null | [
"https://extension.psu.edu/programs/4-h/projects/poultry/embryology/teacher-resources/faqs",
"Yes. It is a rare occurrence. When two chicks hatch from the same egg, the egg usually has two yolks. Usually, one embryo out competes the other and only one chick survives to hatch. Many time both embryos die before hat... | [
"Actually, the development of viable twin chicks from a single-yolked egg has been observed twice, once in domestic chickens (Nalbandov 1942) and once in pigeons (Levi 1941)."
] | [
"Siamese twinning does happen in reptiles. Two headed snakes are known from many species (",
"the san diego zoo had one",
"), and two headed turtles ",
"have also been found",
".",
"In these species you can get twins, too, though they don't make the news in the same way."
] |
[
"Impractically conditioned brain"
] | [
false
] | [deleted] | [
"There's this phenomenon with trying to break a habit called resurgence. Resurgence is when you've stopped doing X, but suddenly you start doing X again. This time it's a little easier to stop doing X, but then it comes back again. This happens multiple times before a habit is truly gone. So don't get discouraged w... | [
"It's certainly possible, just takes a good degree of willpower and self-control, which is where most people fail.",
"I don't know of the scientific backing behind this but a rule of thumb is that it takes about a month to change a habit. "
] | [
"Well it really depends on the type of habit and how you are trying to change it. You can stop chewing your fingernails and don't feel agitated about it in 3-4 days.",
"Stop getting distracted by interesting things can take MUCH longer than a month though, even if you work on it."
] |
[
"How are routers capable of handling multiple devices at once on the same wifi network? Wouldn't there be some kind interference between all of the devices?"
] | [
false
] | null | [
"The transmission protocol that is in use in most wifi routers is IEEE 802.11. WiFi uses a half duplex transmission mode meaning that messages are transmitted and received on the same frequency. The problem that you have guessed is that two transmissions may collide with each other causing a failure. This is actual... | [
"Well put. Of note, the protocol specifies a random wait time in the case of a collision. This makes it so that two devices don't keep colliding with each other."
] | [
"The router sends out each packet with an address. If your device gets a packet not addressed to you, it discards it. Your device will only keep packets addressed to you.",
"You might think, well what if I hack my computer to accept other people's addresses, couldn't I just snoop on them?",
"Yes, yes you cou... |
[
"Why do certain medications need to be taken during dinner, after dinner, etc? What makes the difference? How harmful is it to not do it at the specified time?"
] | [
false
] | null | [
"A lot of it has to do with interactions with other drugs and eithfood and withtgewau the body breaks down the drug so you actually get it. Medications that have to be taken before food generally need the acid of the stomach to break them down for absorption. Medications that need to be taken with or after food gen... | [
"All has to do with how it breaks down in the body, and in some cases, whether or not nausea is a common side effect. (Eating with those medications sometimes calms that effect.)",
"Not crazy harmful, but not as effective as they could be."
] | [
"Because of your stomachs high pH its tissue lining is constantly renewing itself so your stomach acid isn't everywhere in your body (this is usually three days). When you take some tablets like paracetamol without eating it breaks down your stomach lining faster than it can renew itself causing internal bleeding a... |
[
"Of all the academic and/or professional studies done about RISUG, the male contraceptive, what can consumers expect in the next 5 years? 10 years? Further?"
] | [
false
] | I read an article recently about RISUG, the male contraceptive that allegedly lasts 10 years or more with 100% effectiveness. As a young man in my 20s, I was wondering, based on academic and professional research, whether or not it is safe, viable for production, or likely to become available anytime soon. I want kids ... | [
"The issue is that the clinical testing required by the FDA to ensure efficacy and safety are extremely expensive, but the potential for making a profit selling that kind of contraception is basically nil, so alternative sources of funding for the clinical testing are needed to move forward."
] | [
"The FDA can grant \"orphan\" status to drugs that treat certain diseases where the return on investment for bringing those drugs to market isn't very high. Orphan drugs get certain benefits including longer patent life to give more time to recoup money. If the FDA were to extend orphan status to male contrace... | [
"Orphan drug status in the U.S. requires that the disease affect less than 200,000 Americans."
] |
[
"Which single species accounts for the largest portion of earth's biomass?"
] | [
false
] | Also, since some population models predict human numbers rising to 15 billion this century, will this change our rank in terms of biomass and what are the environmental effects of having so much additional water contained within ballooning human biomass? Source: | [
"That might well be true, but bacteria aren't one particular species. Actually it's not clear if bacteria even HAVE species in the way that animals and plants do."
] | [
"The ",
"AntBlog has a good answer to that question.",
"TLDR: By mass, cattle beats human, weighing about twice as much. Lots of krill, but probably they only weigh as much as humans."
] | [
"Have no clue as to whether Stephen Gould knows what he's talking about; but he makes the case that bacteria may have more biomass than plants and animals.",
"http://www.stephenjaygould.org/library/gould_bacteria.html",
"But new discoveries in the open oceans and Earth's interior have now made a plausible case... |
[
"Do \"lazy eyes\" expand a person's field of vision or is vision unaffected?"
] | [
false
] | null | [
"I have a lazy eye, I can confirm this is the case. I do not see one larger \"picture\", but one view at a time (usually my left as the lazy eye is mostly blinded as well)."
] | [
"I have a friend with a lazy eye, and he told me that he sees two separate pictures and he can only pay attention to one at a time. (Normally, the brain combines the pictures from both eyes and makes a single 3D picture.) So, I believe that even if the overall field of view that his eyes are seeing is larger, it ... | [
"And confirmed again as a wearer of a lazy eye.",
"I primarily see from my right eye, and my left eye has been little more than peripheral for almost all my life. I'm taking steps to correct the vision and doing exercises to try and force the brain to complete the connection, but this will very likely take a long... |
[
"Do neurons have their own genome?"
] | [
false
] | My AP Biology always said that all the cells in a your body have the same DNA but a few articles on the internet like this one ( ) say that neurons often have different ones and even unique to a specific neuron. So who is right? | [
"Good question. All cells in your body start off from the same genome. Every time a cell divides, that genome gets replicated. DNA replication in humans is really, ",
", long-slow-whistle-sweet-baby-jesus accurate. But it's not perfect. ",
"This guy",
" did the math, and estimated that every time the genome i... | [
"To be clear, most cells do not in fact contain the exact same DNA pattern. One simple reason: mutations. All DNA will undergo natural mutations. This article is saying that neurons have a high rate of mutations. So yes, their genome is different than a heart cell. But the heart cells genome are going to be differ... | [
"The reason to that (from what I understand) mitochondria has their own DNA is that they are organelles then? Does this mean they can differ this same way or are they unique?"
] |
[
"Why are some cooling towers at power plants \"hyperboloid\" shaped?"
] | [
false
] | null | [
"Just from the structural side, a 'hyperboloid of one sheet' (which is the kind of hyperboloid they are) can be constructed of straight segments on two biases, cris-crossing. Depending on the eccentricity of the hyperboloid, each straight member crosses several of the ones in the other direction, this allows it to... | [
"Here's a picture",
" that helps visualize the design. "
] | [
"From the functional side:",
"-those cooling towers have fill material in them which the water is sprayed onto and trickles down. This has the effect of increasing the surface area of water available to make contact with the cooler air and increasing the effectiveness of the tower. The wide base of a hyperboloid ... |
[
"I think I may be experiencing something called derealization. Can anyone tell me about it?"
] | [
false
] | [deleted] | [
"Your doctor. Also, it will take more than one visit for any doctor to seriously consider the claims. "
] | [
"As the other person said, go to a better doctor. Also remember that a traumatic event is anything that traumatizes you. I know that sounds redundant, but an incident that may seem completely harmless to others can still leave lasting psychological damage. Again, if it's a problem for you see another doctor."
] | [
"No need for you to apologize, your concern is understandable and it's good to ask for outside help/advice. I hope someone in this field sees this thread.",
"I'm certainly not even close to being any kind of expert in this field, but in my personal opinion (backed by some life experience with a similar issue), I ... |
[
"Is there any way to describe the right-handedness of a coordinate system without resorting to hands?"
] | [
false
] | [deleted] | [
"The ordered triple <",
", ",
", ",
"> is a right-handed basis of ",
" if and only if det(",
", ",
", ",
") > 0. This is the only definition of right-handed."
] | [
"The definition ",
"u/Midtek",
" gave is the correct definition and the one we use in higher level mathematics. But usage of this definition assumes some comfort in determinants which is not strictly necessary here.",
"One of the reasons left-handedness is different from right-handedness is that you cannot go... | [
"The ordered basis ",
" the coordinate system. <",
", ",
", ",
"> is not the same as <",
", ",
", ",
">"
] |
[
"In the long run, is worldwide income/wealth inequality increasing, decreasing, or fluctuating around a mean?"
] | [
false
] | [deleted] | [
"The details will of course vary from country to country. In Europe for example, the biggest trend is that inequality has been lower in the 20th century than at any point over the past few centuries. However, on shorter time scales, inequality has both increased and decreased.",
"To get a better sense of these fl... | [
"I second this book recommendation. It's a great overview of the history of economic inequality.",
"To summarize Picketty's argument in the simplest of terms, inequality tends to be higher over time because the rate of return on capital investments is higher than the rate of economic growth. People that already h... | [
"Some of the responses here are not correct. ",
" wealth inequality is most definitely decreasing.",
"This is because globalization (e.g. immigration, trade, internet, etc) has made it possible for people to exchange goods and services across national borders in a way that just wasn't possible before. ",
"Thi... |
[
"Does the infinite multiverse theory assume that in addition to every possible scenario existing, every impossible scenario also exists?"
] | [
false
] | I'm having a hard time reconciling the concept of infinity with the idea of complete improbability. According to (one of the many) multiverse theory, there should exist an amount of alternate universes, thus there must be one for every conceivable outcome to have taken place since "the beginning". Following this reaso... | [
"The short answer is no. If a particular scenario is by definition ",
" then it ",
" come about. However, given enough time, ",
", but still possible, events can take place.",
"But to understand why this is the case it would help to review the argument you are proposing more fully.",
"No doubt, the model ... | [
"First there's no such thing as \"infinite multiverse theory\"",
"What you are thinking of is ",
"the Multi-World Interpretation of Quantum Mechanics",
". ",
"From that it ",
" be noted that this pertains to ",
" not your choice of sock color, nor your dinner selection. So unless you use some kind of qu... | [
"First there's no such thing as \"infinite multiverse theory\"",
"Far outside mainstream scientific opinion (actually, outside of science entirely) is Max Tegmark's ",
"Ultimate Ensemble",
" theory, which could reasonably be called an \"infinite multiverse theory\".",
"Also:",
"Since no measurement will s... |
[
"Would it be possible to survive inside a blue whale for a short period of time?"
] | [
false
] | Slightly ridiculous question, I know, but it just got me thinking. Lets say you somehow find yourself inside the mouth of a blue whale. Could you survive for minutes? Hours? Is there somewhere where water doesn't breach, and is there any oxygen there? | [
"The inside of their mouths are filled with water and whale spit. There is no air in there, so you would survive as long as you could hold your breath, then pass out and inhale whale mouth juice and drown. So minutes is the answer."
] | [
"According to this ",
"article",
":",
"The blue whale also incidentally consumes small fish, crustaceans and squid caught up with krill."
] | [
"\"Despite the size of its mouth, the dimensions of its throat are such that a blue whale cannot swallow an object wider than a beach ball\" - en.wikipedia.org/wiki/Blue_whale"
] |
[
"What was the first domesticated animal?"
] | [
false
] | And does it differ area from area; did the humans in Mesopotamia domesticate one animal and those living in South America some other first? | [
"We currently believe ",
"dogs",
" were the first animals to be domesticated, around 15,000 years ago, but that date is fuzzy. It may have happened multiple times in different places, but we also have no good way to tell for sure. Dogs predate other domesticated animals by thousands of years, and seem to have s... | [
"I'd be surprised if this wasn't the case... I can't see a lot of impetus for a person, in a world where domestication isn't even a concept, to go out and trap literal wolves. We think cats domesticated themselves too, by choosing to voluntarily hunt near granaries in human settlements where rodents were more dense... | [
"There is some debate whether humans domesticated dogs, or dogs domesticated themselves. Wild dogs may have invited themselves into human groups, rather than humans actively capturing wild dogs."
] |
[
"Why is it telephone calls broadcast on radio programmes still sound muffled and dodgy?"
] | [
false
] | Phone call quality between mobile handsets or even VoIP have reached a point where everything's pretty much crystal clear. Why is it when a phone call is broadcast over the radio, it sounds bad? I feel like the technology to make the call sound like the person speaking is physically present in the studio should already... | [
"The technology required to produce high quality sound from an extremely small receiver does exist. The problem is that it isn't exactly cheap. Remember that phones aren't designed to produce high quality audio. They're for personal communication. When we make a call, the speaker at the other end isn't designed to ... | [
"You have messed up the frequencies a bit. The Nyquist frequency of a telephone is 4 kHz indeed, that means the sampling frequency is 8 kHz. OTOH, 44.1 kHz is the sampling frequency of an audio CD, the Nyquist frequency being 22.05 kHz.",
"I hope this clears up any doubt about it."
] | [
"It's the ",
"nyquist bandwidth limit on the telephone system",
"; it's much smaller than that of the studio equipment."
] |
[
"Does volcanic magma originate in the Earth's core?"
] | [
false
] | Has the magma that erupts from volcanoes come from the core of the planet via a rupture in the mantel? If so, what prevents more of the core, which I understand is under around 30 million psi of pressure, from spewing forth? What is lava's "coagulant?" Just heat/pressure loss? | [
"Virtually all lava erupted at volcanoes is derived from partial melting of either the crust or the upper portions of the mantle. Even in mantle plumes, which are theorized to originate at the core mantle boundary and produce hotspot volcanism in places like Hawaii or Iceland, the actual melting does not occur unti... | [
"Awesome explanation! Thanks!",
"I can't wait to check out that link and graph when I get home.",
"Do we know what kinds of phenomena move rock upward at the speeds required for mechanism 2 to occur?"
] | [
"This made me think of a question: If I had a container with ten pounds of water and a thousand pounds of oil on top of it, the oil would, of course, float. If I were to open a channel through the oil to the water, say a straw, wouldn't the mass of the oil be enough to push the water up through the straw?",
"Intu... |
[
"How is blood type determined?"
] | [
false
] | [deleted] | [
"Its pretty easy to measure blood type. You can use antibody binding to test for presence of A or B antigens in your blood.",
"If you have only A, then you are type A.\nIf you have only B, then you are type B.\nIf you have both, you are type AB.\nIf you have none, you are O."
] | [
"And how do they find the resus ? What this even mean ?"
] | [
"Rhesus, aka Rh has an antigen called D. It works the same way as with the ABO system, you use antibodies for the D antigen(anti-D) and check if there is a reaction or not."
] |
[
"Why does general relativity cause asymmetry in spectra-graphs?"
] | [
false
] | A professor told me this, but I cannot find any papers or videos on it. Why does it create an asymmetrical "tilt" in peaks on spectras? | [
"Maybe you're thinking of ",
"gravitational redshift",
"?",
"Gravitational redshift results in the shifting of spectral lines in response to gravity (e.g. a photon moving upwards on Earth loses energy and becomes redder) and/or the expansion of the universe (photons coming from far away appear redder because ... | [
"But it's very nearly conserved in the systems that nonabeliangrape is referring to. Close enough that the thought experiment is still valid.",
"Of course, general relativity isn't really about thought experiments - those are just to help understand things more intuitively. You can do the calculations - using the... | [
"Conservation of energy (mass is included in this) only holds when physics doesn't depend on time. This is a consequence of ",
", which links symmetries of physics to conservation laws.",
"Here's a nice example. Take the expanding Universe, which pretty clearly depends on time. Consider a ball of photons, or li... |
[
"Question about refraction."
] | [
false
] | [deleted] | [
"The full equation you're talking about is c/n = f*l, where f is the frequency, l is the wavelength, c is the speed of light, and n is the index of refraction of the material. The frequency f (which is directly related to the energy of the light) doesn't change. So if some light enters a medium it's velocity and wa... | [
"They detect the energy of the photon. It's a shortcut to refer to the energy of a photon by its wavelength, because nanometers is a more relatable unit than something like eV. The implied assumption when doing so is that you're talking about the wavelength in a vacuum."
] | [
"They detect the energy of the photon. It's a shortcut to refer to the energy of a photon by its wavelength, because nanometers is a more relatable unit than something like eV. The implied assumption when doing so is that you're talking about the wavelength in a vacuum."
] |
[
"Why are the cave drawings of France, which are older than the Native American Southwest rock art, so much more sophisticated and accomplished?"
] | [
false
] | The cave drawings of France, such as the Chauvet cave, is being dated at 28 to 40 thousand years ago. Why are they so much more artistically accomplished than the Native American Southwest rock art (13-15 thousand years?), which seems consistently crude by comparison? I’m not asking this in a judgmental sort of way, ... | [
"r/Anthropology",
" might be able to help you."
] | [
"\"they are so much more artistically accomplished\" - can you provide source/images that formed your opinion? I found images on IMHO similar level."
] | [
"I don't agree about the artistic value. The Native American art however had rather significant symbolic use and value. So you are likely seeing less art and more message. The cave artist was likely drawing deer, the Native American was likely presenting a religious message to a specific deer god. Or telling a stor... |
[
"I am a staunch supporter of Nuclear Power. Can someone give me a few reasons why nuclear power is NOT viable?"
] | [
false
] | null | [
"The ",
" resistance to nuclear power is a major problem. It's been that way for decades and is unlikely to go away.",
"Given the anti-science trends in the US, it's likely to get worse, not better."
] | [
"a small mistake kills thousands and the environmental ramifications are disastrous - Fukushima being the most recent example.",
"Using LNT (a conservative method) to approximate health impacts of the Fukushima accident, there will be somewhere on the order of 10-100 excess cancers to people outside of the worker... | [
"Somewhat related, and also interesting to read, is David MacKay's book, ",
"sustainable energy - without the hot air",
". I recommend the whole book, but the chapter on nuclear power is a good read as well when talking about the numbers. "
] |
[
"My pretentious rules for pluralization of units..."
] | [
false
] | So for a long time now (I've got a BS and MS in physics, working on a PhD) I've always believed that one should only pluralize units when the magnitude of the quantity is greater than one. So for example, "0.5 meter" as opposed to "0.5 meters". I was just explaining this to someone and realized I don't remember where... | [
"Hipstre, pleeease."
] | [
"Myself, I'd say \"half a metre\" or \"0.5 metres\". I only tend to use the singular for exactly one of a thing. Any mutliple, even multiples less than one, just doesn't sound right without the plural."
] | [
"Alley's Craft of Scientific Writing, doesn't go over this topic specifically, but does include a place where he writes",
"\"... the eruption of Mount St. Helens in 1980 had an ash plume that reached 19,000 meters and dispersed 0.67 cubic kilometer",
" of material into the atmosphere ...\".",
"This goes with ... |
[
"Knowing the mass of a star, is there a maximum allowable distance of orbit?"
] | [
false
] | null | [
"In an isolated 2 body system (that is there is nothing else in the universe) there is no maximum distance.",
"In reality the answer will be the Hill sphere of the star in relation to the nearby stars. In less technical jargon, the maximum distance will be dependant on how far you can travel from the star before ... | [
"how much thought is there on the concept of gravity being perhaps not exactly the inverse square of the distance at all distances, and how that might explain a portion of the dark matter and dark energy problem?"
] | [
"They could remain in orbit and not collide (depending on a lot of other physics like how each object evolves in time)."
] |
[
"Two Drones Flying Away From Each Other Along the Equator; Does the Earth's Rotation Affect the Length of Ground Covered By Each Drone?"
] | [
false
] | Sorry if this has been asked before, it's difficult to come up with an appropriate search term. If two identical drones, hovering a foot off the ground, are placed back-to-back on the earth's equator (parallel with it), and each is then propelled forward along the equator (i.e. directly away from each other) at a fixed... | [
"Two quibbles: \"Variable wind resistance\" doesn't make much sense in this context. \"Variable wind\" does.",
"\"Fixed speed\" is meaningless unless you specify with reference to what. Ordinarily, an aircraft flies at a fixed ",
": i.e., speed with reference to the airmass.",
"The rotation of the earth will ... | [
"So, here is a fun way to visualize the problem with the question:",
"Take 3 drones to a point on the equator. Set 1 to travel east to west at a speed where it will fly around the world in 24 hours. Take the second drone, set it to fly west to east around the world in 24 hours. Set the third to hover. Now wai... | [
"Damn, this is what a lack of education looks like; I can't even formulate the question correctly because I don't know the most basic terms! 🤦",
"Thanks for the clarifications/answers, they've helped me get to grips with the whole thing."
] |
[
"When prey is swallowed whole, what can kill it once it is in the digestive tract?"
] | [
false
] | This photo propmted the question: What would kill the frog once it is swallowed by the fish? What other ways to prey meet their end inside the gut of large predators? Whale? Snake? Chameleon? Other examples you might know? | [
"Most animals have many mechanical and chemical means of digesting their food after being swallowed whole. I believe frogs and other reptiles have hard bony structures towards the back of their throat that crush living organisms that pass through. They also have strong digestive acids and enzymes which begin to bre... | [
"Is that what the frog in the linked picture is sitting on?"
] | [
"Not exactly sure. Looks like the frog is just situated in that fish's throat. ",
"That fish likely has pharyngeal teeth that would break that frog down though",
"."
] |
[
"Phosphorus can make 6 covalent bonds?"
] | [
false
] | I was reading my text book and I found the molecule PF6 . Which is supposed to have an octahedral shape. I can't understand how phosphorus, which has only 5 valence electrons, can bond with 6 atoms of fluorine. | [
"Fluorine is extremely electronegative and will bond like crazy to anything it can, and phosphorus can also 'expand it's octet' meaning electrons can move up from the 3p orbital to the 3d orbital which can accommodate more bonds. These two factors help make the six bondson phosphorus more stable. For comparison flu... | [
"You say that like you think he doesn't know. He clearly means no 'free' valence electrons. The fact that it has a closed shell and will still react is the relevant information, don't be pedantic."
] | [
"You say that like you think he doesn't know. He clearly means no 'free' valence electrons. The fact that it has a closed shell and will still react is the relevant information, don't be pedantic."
] |
[
"Does the speed of light limit the speed at which molecules vibrate, and if so, does this mean there is a limit to how hot something can be?"
] | [
false
] | null | [
"Does the speed of light limit the speed at which molecules vibrate",
"Yes. ",
"and if so, does this mean there is a limit to how hot something can be?",
"No. There is not limit to how much energy an object can have from relativity. As a particle approaches the speed of light, its energy will grow without lim... | [
"Yes, in principle a system with sufficient internal kinetic energy could form a black hole. The temperature of a system actually contributes to its rest mass! "
] | [
"Shouldn't a black hole form as energies reach absurd levels?"
] |
[
"Are nocturnal animals active for longer periods in the winter?"
] | [
false
] | Are nocturnal animals generally active as long as it's dark outside? Or do they tend to keep similar hours regardless of the proportion of light and dark in a day? Like, the sun goes down around 1700 right now where I am, will wolves become active as soon as it is dark, or will they wait until around 2200 when the su... | [
"Your question isn’t as straightforward as it seems because many animals aren’t strictly “nocturnal”, different populations of them may tend to be active at different times for different reasons other than just night/day (such as local human activity, weather/temperature, availability of food during a particular ti... | [
"Very interesting! Thank you."
] | [
"thank you so much for the detailed response man it was such an interesting rabbit hole"
] |
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