title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Is a difference in pH the only consideration when it comes to an acids ability to dissolve substances?"
] | [
false
] | [deleted] | [
"No, with aqua regia (\"royal water\"), a 1:3 mixture of nitric acid (HNO3):hydrochloric acid (HCl) being one of the best examples when it comes to dissolving solid Gold (Au). While both of aqua regia's components are strong acids, they are not able to dissolve solid Gold by themselves. The mechanism by which the G... | [
"I just want to add: sulphuric acid's dehydrating ability is related to its acidity. The protonation of hydroxyl functionality creates a water leaving group which readily leaves the molecule. ",
"Hygroscopicity is related to the ability of a substance to absorb water from the vapour phase through incorporation of... | [
"Good question! To be honest, I don't know. I'm just a biochemist by training, this is be something an inorganic chemist would know. Both the solubility of KCl and KNO3 are high enough that there shouldn't be any problems getting to similarly high concentrations of NO3",
" and Cl",
" as in classical aqua regia.... |
[
"Dad wants to know - Does the claimed science behind Simple Water Fuel (HHO) produce legitimate results? - xpost from askreddit"
] | [
false
] | Hey Reddit. My dad owns an auto repair/body shop and is interested in testing if Simple Water Fuel works to improve car mileage. Judging from the I'm already doubtful. . What I would like explained is just the claimed science behind the product, which is using electrolysis on water and then injecting the results into the engine along with the normal fuel used (gasoline/diesel). Reddit, could you explain if this would result in an increase in gas mileage? | [
"This is not absolutely a scam, but it's pretty close. ",
"What they are leaving out is it's a mixture fo hydrogen and oxygen that's being burnt, which is all well and good. But what's being left out is where the hydrogen and oxygen come from and how much energy it takes to accomplish this. If you include this... | [
"Everything I know about cars comes from watching entirely too much \"Top Gear.\" (I can't help it. James is just so ",
"But with that caveat, my meagre understanding is that gasoline is carefully formulated specifically to ",
" the release of excess hydrogen during combustion, which reduces engine efficiency i... | [
"Well i would say it's absolutely a scam, they're selling a product that is physically impossible and making ridiculous claims about how awesome it is.",
"Think about it, if this would truely be working, what would have happened long ago to the world's energy problems?",
"The reason why this isn't working is re... |
[
"By what methods do isolated ponds get fish in them?"
] | [
false
] | There are a lot of isolated ponds out there with no connection to waterways. Like the ponds here and there on a farm, or the display ponds where I work. They all seem to have fish in them, usually little sunfish, none bigger than a few rare 6-7 inch specimens. How do these fish get to the ponds? I realize there's a variety of methods, probably things like stocking by humans or fish getting washed into a pond by floodwaters. Are there any more exotic or unusual methods? | [
"Also migratory birds and waterfowl transfer amphibian and fish eggs. The eggs attach to the legs, down, feathers of the bird and are deposited (washed off) when the bird enters the next water source."
] | [
"There's the few you mentioned, if it's a display pond, then definitely by human stocking! Flooding is also another common one. You also have to remember that just because a pond isn't connected to a waterway now, doesn't mean it wasn't in the past. It could have been connected for years previously, or again, throu... | [
"This one actually seems pretty likely for the specific ponds I'm thinking of, as they're frequented by migratory birds and waterfowl."
] |
[
"Why do meteors get burnt up in the atmosphere and Felix Baumgartner didn't (Red Bull Stratos)?"
] | [
false
] | From what I understand, meteors, for the most part, get burnt up and disintegrate from entering the Earth's atmosphere. Felix Baumgartner jumped from 128,100 feet high unharmed. | [
"He didn't start at speeds exceeding terminal velocity. ",
"The meteors have great energy and as a result meet a great deal of resistance from the atmosphere that you wouldn't if you started at a low velocity and accelerated due only to gravity."
] | [
"Atmospheric \"burn up\", what is normally called the ",
", occurs at speeds of Mach 5 or higher. Spacecrafts returning from orbit usually arrive at Mach 23. Meteors can be even faster.",
"Felix Baumgartner merely reached Mach 1."
] | [
"Kinetic energy scales relative to the square of speed. Baumgartner fell while within the atmosphere, and his speed only got as high as about mach 1.25, reaching a maximum speed of about 377 meters per second. Compare that to a meteor entering the atmosphere at above 11,000 meters per second. The meteor has about 8... |
[
"How does solidifying candy (power to solid) work?"
] | [
false
] | Flaired under chemistry as it seems the most relevant to this "food science" question, although physics might also be relevant. There seems to be , and combined to create a solid strip of candy upon being pulled out and exposed to air. What stages/processes might be involved in this, or how does something like this actually work? (E.g. why does it not solidify into a lump when it is already suspended in the solution without being pulled out?) | [
"Aha! This was new to me but I figured it out. ",
"Here's",
" a video that shows someone making the candy in more detail. ",
"Here's",
" a web page with an ingredients list in English. And here's an article on gummy chemistry:",
"https://www.sciencedirect.com/science/article/pii/S1878450X13000073",
"... | [
"Yeah, though the chemistry is different. 2-part resin adhesives work by building long chains from small components; alginate gels work by cross-linking pre-existing chains together. It's the difference between making a chain, and making a chain-link fence."
] | [
"If that is what I think then the powder has gelatin in it to act as a binder. ",
"The powder is carefully placed in the water so that only the outer edge of the powder mass is in contact with the water and forms into relatively rigid cross linked gelatin protein. ",
"As the wire slowly lifts the mass more gela... |
[
"Are there measurable tides in the hydrocarbon lakes of Saturn's moon Titan?"
] | [
false
] | Would these tides be massive due to the intense gravitational attraction of Saturn | [
"In that article, the surface they're referring to is the actual, physical surface of Titan. Basically, from gravity measurements, we can tell that the shape of Titan is changes during an orbit, in response to tides. If this result holds up (it may or may not), then it would be good evidence that Titan has a subs... | [
"Are there measurable tides in the hydrocarbon lakes of Saturn's moon Titan? ",
"Here seems to say yes but I don't understand the details - it apparently says that the \"surface\" of Titan rises and falls, but I don't understand \"surface of what exactly\" they mean. ",
"http://www.nature.com/news/tides-turn... | [
"That's kind of what I expected since I could find no data online about it. Thanks."
] |
[
"Is it even possible to successfully send a probe to another star?"
] | [
false
] | In Carl Sagan's Pale Blue Dot there's a part where he talks about Voyager 2's flight path as it approached Uranus. Here's the exact quote: JUST BEFORE VOYAGER 2 was to encounter the Uranus system, the mission design had specified a final maneuver, a brief firing of the on-board propulsion system to position the spacecraft correctly so it could thread its way on a preset path among the hurtling moons. But the course correction proved unnecessary. The spacecraft was already within 200 kilometers of its designed trajectory-after a journey along an arcing path 5 billion kilometers long. This is roughly the equivalent of throwing a pin through the eye of a needle 50 kilometers away, or firing your rifle in Washington and hitting the bull's-eye in Dallas. He compares the spacecrafts' trajectory to threading a needle from 50 km, which basically seems impossible. The distance from Earth to Uranus is small compared to the distance of the nearest star. So I'm asking, is it even possible for us to successfully send a probe to another star? If sending a probe by Uranus is like threading a needle from 50 km, then sending one to another star should be like throwing a pin through the eye of a needle on the moon, right? If it's possible to send a probe to another star, then how much more difficult would it be to send one to an exoplanet in another stars system? How about a moon? | [
"It's already been done. Or rather, is presently being done. Voyager 1 is on its way to a relatively close encounter — within two light-years — with a star so completely unremarkable it doesn't even have a name, just a catalogue designation. It'll get there in 40,000 years.",
"That's a bit of a cheat, though. Bec... | [
"It would be difficult, but one advantage is that unlike Uranus, a star has an enormous gravity well that dominates the local region. Once the probe got close enough, it is going to ",
" to fall towards its stellar destination.",
"So it is less of a bullet, and more of a guided missile. "
] | [
"Voyager will pass within two light-years of said wholly unremarkable star, which is currently 17.6 ly away."
] |
[
"Why are able to clearly see our own thoughts. Even if we have never seen it before, we can always see it in our heads. How?"
] | [
false
] | null | [
"Apparently not everyone can:",
"http://boards.straightdope.com/sdmb/archive/index.php/t-310467.html",
"http://ask.metafilter.com/143968/I-cannot-mentally-visualize",
"http://dfan.org/visual.html"
] | [
"Reading those has only made me paranoid. I'm not sure what \"visualizing\" is supposed to mean anymore.",
"Just to be sure here, imagining a visual image is absolutely nothing like seeing one, right?"
] | [
"[citation needed] please "
] |
[
"Can prolonged tachycardia cause the heart to be sore?"
] | [
false
] | I understand that the heart probably won't hurt after exercise from soreness, but if the heart is beating ~50 bpm faster than normal for multiple day and nights in a row, can that cause the heart to be sore? | [
"Sensory nerves innervating cardiac muscle is very different from the sensory nerves that provide sensory information from skeletal muscles (the soreness you're most familiar with after exercising those muscles to exhaustion). The only \"pain\" sensation I'm aware of that cardiac muscle can send is a sensation of p... | [
"In short, yes. If your heart is beating too fast to get enough oxygen, lack of oxygen to the heart muscle can definitely cause pain. ",
"Lack of oxygen is called \"ischemia\" and it is very painful. This is what causes the pain of a heart attack. Blood flow to one area of the heart gets blocked, and the lack of ... | [
"Depends on what causes it - stimulants like cocaine, as well as things like anxiety will cause chest pain. ",
"I’m sure extended (multiple consecutive days) periods of a high heart rate will cause some kind of trauma but this is how all muscles strengthen. ",
"We are endurance animals after all. I’m sure exerc... |
[
"I read somewhere that the application of quantum mechanics helped the development of things like tv's and lasers. What are some examples of how quantum mechanics have been used for our modern conveniences?"
] | [
false
] | null | [
"Such open-ended questions are better suited for our new-ish sister sub ",
"/r/asksciencediscussion",
". Please consider reposting there instead."
] | [
"ok I'll post there. Also how can I make the question less open ended? Should I just ask about one specific technology?"
] | [
"Yes -- asking how a specific thing works is good! You might be able to find an answer to your original question with a simple Google search"
] |
[
"Assuming infinite access to resources, how long could you sustain a sun by e.g throwing vast amounts of hydrogen into it?"
] | [
false
] | So assuming you have infinite access to anything what the longest amount of time you could keep a star fusing by throwing things into it (but not doing things like extracting elements e.g iron) before it say eventually collapsed into a black hole. Could you just keep throwing more resources into it by order of magnitude to keep it going forever or, if not would the smallest star possible still fuse longer because a smaller star fuses elements slower and possibly still takes longer to produce elements it cant fuse for energy? | [
"It's the latter (sort of). The more massive the star, the more fuel it has to burn, but the faster it will burn through it. So, more massive stars have shorter lifetimes and the least massive stars have the longest lifetimes."
] | [
"There are a few interesting things about this question.",
"The thought that other commenters have touched on is that adding mass to a star makes it's core higher pressure and temperature so increases the fusion rate. This makes the star brighter but at the expense of longevity so you would have made the Sun last... | [
"I'm not sure if your response addresses OPs assumption of unlimited hydrogen to keep pumping into the star regardless of size. Can it be kept going, or will fusion break down eventually regardless of available fuel?"
] |
[
"A test for the BRCA gene cost about 4000 USD (according the Fred Hutchinson Cancer Research Center). Sites like 23andMe run genetic tests for as little as 99 USD. What is the difference and is the price discrepancy justifiable?"
] | [
false
] | null | [
"The gene-testing field has gone through a lot of upheaval in the last 12 months. The answer to your question is actually one based more on legal restrictions than biological restrictions.",
"As of late last year, 23andMe can no longer do medicine-based analysis of your DNA (only hereditary). Meanwhile, one of th... | [
"Thank you for such a thorough answer. Much appreciated!"
] | [
"Thanks! Glad I could help."
] |
[
"Given the observational data available at the time of its acceptance, was geocentrism a valid theory?"
] | [
false
] | Of course with today's knowledge we know that it wasn't , but I'm curious to know if the Earth-centric view was one that satisfactorily described the night sky observations during the time of its reign. If there were discrepancies even back then, (i.e. the motion of a particular planet that just didn't quite make sense) how were they reconciled? Were there people who were aware of these problems and made attempts to resolve them or were they swept under the carpet and hoped to be forgotten? Thanks! | [
"The main issue was stellar parallax. If the Earth is moving around the sun then the stars should be in slightly different places depending how far away they are. The ancients mentioned this, but could not observe it.",
"The issue is that the parallax is very, very small. It wasn't observed until Bessel I believe... | [
"Given that the entire point of the model at the time was to predict the position of the planets in the sky - often in order to construct horoscopes - and not to determine their actual position is space, the geocentric theory worked remarkably well for nearly two thousand years.",
"With the geocentric Ptolemaic m... | [
"Heliocentrism implies stellar parallax, and if the observed parallax is zero, that's a case against it.",
"I think that it is worthwhile to note that Tycho Brahe measured the distance to comets using parallax, and because his observations failed to find any stellar parallax as it is insanely tiny, he concluded t... |
[
"Why are paranoid thoughts so common with schizophrenia?"
] | [
false
] | null | [
"I am not schizophrenic, but I did have a number of stress induced psychotic episodes, the symptoms of which can be very similar to some schizophrenic patients, and I feel you are missing a crucial part of the explanation.",
"Psychotic symptoms tend to cause your mind to be unable to distinguish between your imag... | [
"I'm not sure exactly what question you are asking here. Schizophrenia is characterized by the presence of hallucinations and delusions, as well as meeting criteria for \"negative symptoms\" such as flat or inappropriate affect, reduced speech, inability to feel pleasure, lack of motivation, etc.",
"These halluc... | [
"This seems like a fun thing to think about and I’ll give it a shot.",
"So, first up Schizophrenia is a syndrome of psychosis. Psychosis is a very broad term which covers a range of phenomenon which result as a problem with ‘reality testing’. As rightly said previously the symptoms of this disorder are broadly lu... |
[
"Can we make a super nutrient-dense pill to distribute to people in third world countries?"
] | [
false
] | null | [
"we do have these crackers/biscuits that are used already. they come in packs of 2 and have 2300 calories.\n",
"http://en.wikipedia.org/wiki/BP-5_Compact_Food"
] | [
"Macronutrients (calories) are... big. The best way you can pack them is in fat, at about 600 calories / 100g, and this would still get you at about half a kg (~ a pound) a day - definitely not a pill. Also making a \"complete\" food is expensive. Micronutrients can be packed in a pill, and this is your standard mu... | [
"No.",
"The problem isn't micronutrients... the things you'll find in unnecessary-for-american one-a-day type vitamin pills. The bigger problem for starving people is calories, and you can't compress calories much more than say, the calorie density of butter."
] |
[
"How far down the eukaryote tree into unikonts towards animalia do we find fruiting bodies as a form of reproduction?"
] | [
false
] | People like to mention that mushrooms are closer related to animals than to plants. While pondering thing, I noted that fruiting is something that both plants and fungi use for propagation. I can't think of a quick or easy way to look this up (having to go into each kingdom, etc.) so was hoping someone here happened to know. So what's the closest organism to an animal that still fruits? | [
"The fruiting bodies of fungi and fruit of angiosperms are not homologous structures, they just have similar names. As far as I'm aware, there's nothing more closely related to animals than fungi that has similar structures, though there are other eukaryotes that do this, like ",
"slime molds",
" (amoebozoa), ... | [
"I hadn't thought of it being a reuse of the name for a different biological process."
] | [
"Yeah. I don't even think it would be accurate to describe them as examples of convergent evolution, since they're only very vaguely used for similar functions (i.e., reproduction)."
] |
[
"What exactly happens to metallic objects inside a microwave oven, and why aren't the metallic parts of the microwave itself affected by the phenomenon?"
] | [
false
] | null | [
"Imagine that you are pushing somebody on a swing. If you exert enough force you can make the swing go higher and higher, but only if you push at the right times. This means you must be in phase with the swing. Likewise, a microwave produces light waves that are the same frequency as the natural resonance frequency... | [
"This is a misconception. The frequency of microwave ovens are not near a resonant frequency of water molecules. In essence water can absorb microwave light in the incident frequency range and so it does, so the food gets hotter. There's really nothing more elaborate, no resonant condition, at play."
] | [
"If you had a sphere in the microwave would it arc?"
] |
[
"Could cancerous cells be useful because of their rate of reproduction?"
] | [
false
] | [deleted] | [
"I don't know about other purposes, but cancer cells are used for cell research because of their reproductive properties. For example the HeLa cell line (Can someone link toWikipedia, I'm on my phone), which was used not only for cancer research but also to studie the effects of nuclear bombs and to help develop va... | [
"Here's the link",
". ",
"What's more interesting than the cells themselves is the story behind them and their \"creator\", Henrietta Lacks. The family was not informed about the distribution of Lacks' cells. But unlike other cells, they would not die early and would keep reproducing.",
"Radiolab",
" did a ... | [
"We use multiple myeloma cells to produce monoclonal antibodies. Which are then used in pretty much any sort of immunoassay or immunohistochemistry. These cancerous cells are plasma cells and pump out massive quantities of the exact same antibody. If they are in your body this causes all kinds of problems, but it t... |
[
"Is it possible to \"silence\" a gun like they do in TV/movies?"
] | [
false
] | I know a suppressed gun does not sound like most media make it sound. Would it actually be possible to suppress a gunshot to this extent? If so, what would be required? | [
"Currently no. In fact, \"silencer\" is the less preferred term to \"suppressor\" because the device only lowers the report by at most 40ish decibels. The use of sub-sonic ammo helps to dampen the sound, but at the cost of bullet speed and accuracy. The most effective suppressors that achieve the most noise reducti... | [
"Not sure if the US government didn't supply you with a silencer, or you're a member of the Taliban... "
] | [
"http://en.wikipedia.org/wiki/Supressor"
] |
[
"Can frame dragging tear a hole in space-time?"
] | [
false
] | For example if we had something that spun fast enough rapidly enough (but not enough mass to collapse into a singularity) could it tear a hole? Would the hole be self sustaining or would space fill its self in the way a fluid would? EXAMPLE: Would it be as if you had a drill pressed into a cloth and when you torqued the cloth it rips? or would there just be more space to be pulled in behind the space being torqued? If scenario B is true would the mass of the spinning object increase so high due to the speed of its surface that it would become a massive gravity well? | [
"The answer is the same. There's no such thing as a hole in space, nor a hole in time, nor a hole in spacetime.",
"When we say \"the fabric of spacetime,\" that is just a metaphor. It's not really fabric. There isn't a limit to how much it can stretch, and it cannot be pulled apart. It doesn't make even conceptua... | [
"I'm desperately waiting for an answer. I'm just so curious about this type of topic. "
] | [
"No. There is no such thing as a hole in spacetime."
] |
[
"Is pyrolysis of food possible in boiling water under sufficient pressure?"
] | [
false
] | At sea level, boiling water will not reach high enough temperatures to cause pyrolysis, but if the boiling is done in a pressure vessel so that the water can reach higher temperatures before boiling, is it possible to char food? How high would that pressure have to be? | [
"I'm not completely sure about the chemistry, but for water the maximum temperature at which liquid water may exist is ",
"647K",
" (374 °C; 705 °F), at ",
"minimum pressure 22.064 MPa",
" (3200 psia; 218 atm). ",
"These researchers call 300 °C a low pyrolysis temperature",
" for wood, so it would seem ... | [
"To add to this, the type of product obtained depends largely on the catalyst used. If I remember correctly, basic catalysts promote the formation of oils and alcohols, while strong acids promote the formation of solid carbonaceous residue. So:",
"C6H12O6 > 6C + 6H2O",
"Under acidic conditions, and:",
"C6H12O... | [
"If you put petroleum in a giant industrial steam pressure cooker that's ",
"steam reforming.",
"Under extreme conditions the carbons in hydrocarbons can steal oxygen directly from water. You get carbon monoxide, carbon dioxide, and hydrogen gas. The date of your beef stew is probably roughly similar."
] |
[
"Can a brain ever \"forget\" to wake up?"
] | [
false
] | Excluding coma etc. but during the regular sleep cycle | [
"As in sleep indefinitely? No. Sleep is homeostatically regulated. In other words, as you spend time awake, you build \"sleep pressure,\" which dissipates as you sleep until it is very low and you awaken. This interacts with the circadian system (24-hour rhythm) as well. The only exception I would mention is Kleine... | [
"In other words, as you spend time awake, you build \"sleep pressure,\" which dissipates as you sleep until it is very low and you awaken.",
"Ah okay, thanks. That's one irrational fear off the list."
] | [
"Insomnia can be affected by the circadian rhythm, but it's not a lack of or diminished rhythm. Insomnia that is limited to difficulty falling asleep, rather than staying asleep, may in some cases be due to a circadian phase delay (i.e., body wants to go to sleep and wake up later than \"normal\" in relation to the... |
[
"Do solar winds create drag?"
] | [
false
] | I was watching Spaceballs and after the scene where SB1 passes I got to thinking, would solar winds create any sort of appreciable drag and thus influence the efficieny of travel? | [
"Yes, but it is small unless you are either a dust particle or deliberately trying to catch it.",
"The solar wind near Earth is thin (500 atoms per cubic centimeter) but it is traveling away from the sun at 500 km/s. It is also mostly ionized atoms so you can interact with it using an electrostatic spiderweb sail... | [
"Yes. Each star has it's own unique stellar wind. We have unfortunately only really been able to study the stellar wind of the one star (the sun)."
] | [
"Would the size and type of star have any effect on solar wind?"
] |
[
"Location of Atolls, Atlantic Vs Pacific? And several other Atoll related questions"
] | [
false
] | Hello I've recently been creating a fantasy map and was looking up Atolls and I've several questions about them. The first, is why are there so few Atolls in the Atlantic (only off the coast of Belize) while the Pacific Ocean and the Indian Ocean are chalk full of them. I presume this is due to lack of Volcanic activity in the Atlantic ocean in area where reefs can form but then that leads to another question about the lack of Volcanic hot-spots in the Atlantic. The second question I have is the removal of the former Island that the coral reef rings around. How does this precisely happen? I recall watching a video where it was stated that the weight of the reef somehow has something to do with it, or is it more to do with Erosion (wouldn't a barrier reef prevent erosion to a degree)? And the last question I have is concerning the make up of islands. Since New Caldonia (>40MYA) is older geologically speaking than Midway Island (27MYA) and the two are completely different (one is an Atoll the other is a proper island). Which is a roundabout way of asking, is the geological makeup of an Atoll more prone to erosion than a "regular" island? | [
"The first, is why are there so few Atolls in the Atlantic (only off the coast of Belize) while the Pacific Ocean and the Indian Ocean are chalk full of them. I presume this is due to lack of Volcanic activity in the Atlantic ocean in area where reefs can form but then that leads to another question about the lack ... | [
"I want to thank you for your thorough answer, especially with isostasy which was the part I was most confused about (I understood the coral's growing beforehand) and LLSVP. I do have an additional question in regards to what would be a good book to read, that gives similar detail as your answer."
] | [
"Probably just an introductory geology book would be your best bet. A lot of the details you were asking about are things that would be expounded on more in a plate tectonics text book, but these are usually aimed at students at the end of a BS or in grad school (e.g. the plate tectonics course I teach is a senior ... |
[
"How does a bullet-proof vest stop a bullet?"
] | [
false
] | null | [
"The fibers that make up a bullet proof vest are very tough. When a projectile impacts the material, instead of cutting through the material or causing it to pull apart, the material stays intact. This unyeilding of the fabric causes the impact force of the projectile to be spread out over a much larger area than j... | [
"It's worth adding that ceramic is not useful for the same reason as kevlar, but for the exact opposite. Ceramic would shatter, but in that collision, energy would go into breaking the ceramic before breaking... you.",
"Some recent ideas tried to use non-newtonian fluids as padding for such a reason. These fluids... | [
"The bullet only has as much momentum as the person who fired it has",
"You mean after the gunshot. The recoil."
] |
[
"[Physics] Does photoelectric effect experimental techniques destroy materials?"
] | [
false
] | [deleted] | [
"Outside of testing materials that are known to be sensitive to X-rays (A small and unique subset of materials), XRF spectroscopy is completely non-destructive, so the sample remains physically and chemically unchanged. There are usually more than enough free electrons in the surrounding environment to fill in for ... | [
"You see charging effects in SEM imaging (which usually happens at the same time as an EDS measurement) if the sample is not conductive enough. If the sample is conducive, electrons return to the sample through the grounded stage. "
] | [
"The Photoelectric effect does ionise materials very effectively. If the material is kept in a circuit then the displaced electrons can be kept in a circuit like an ordinary battery, but if the material is isolated then electrons are often ejected, given that the incident photons have enough energy.",
"As for wha... |
[
"Do the components of a black hole's singularity get \"stuck\" on their own event horizon just like any other matter entering the black hole?"
] | [
false
] | Background: User was commenting in the about two black holes colliding, and his main point (best described was that not only should matter approaching a black hole asymptotically slow down to an independent observer as it approaches the event horizon, but the components that initially formed the black hole should as well. If I'm understanding what RobotRollCall correctly, an evenly distributed shell of matter from a collapsing star should naturally act as if all of its mass were at its center singularity. Hence, as the star's matter collapses inward and becomes more evenly distributed, the nature of the gravitation produced by this system should approach that of a black hole. Essentially, there should be an event horizon that forms all the initial mass of the black hole collapses into its singularity (from an independent observer's perspective, of course.) So, my questions are: Is there event horizon that the matter initially forming a black hole asymptotes out to relative to an independent observer? Is that event horizon the same as the black hole's ultimate "mature" event horizon? If that proto-event horizon isn't the same as the event horizon we would observe on a "mature" black hole, does that mean that the event horizons of black holes in general are asymptotically expanding in proportion to our independent observation of the matter constituting their singularity also asymptotically approach an event horizon? The last question is particularly intriguing for me, because if true, it would imply that black hole event horizons change shape over time relative to us as we see their singularity-matter approach a perfectly smeared, even distribution over an event horizon. Then, there would be important considerations involving what happens if an object is approaching a certain event horizon if that event horizon were to change shape. | [
"An event horizon is (somewhat unfortunately) defined in a global sense -- by the separation between the region from which light can't escape to infinity and the region where light can escape.",
"As such, the spatial \"shape\" when you slice spacetime into space and time does change over time, for example when a ... | [
"I don't think it's a useful picture to think of the matter as settling \"onto\" the event horizon. The matter just plunges straight through without a care (the event horizon is a totally regular region of spacetime, with no pathologies).",
"But yes, in some appropriate slicing of spacetime, the event horizon doe... | [
"The surface of the event horizon always \"moves at the speed of light\" -- this is by the definition of the event horizon! Since it separates a region where light can escape and light can't escape, the boundary between those two is a light ray that \"marginally\" escapes (or just hovers there).",
"The matter tha... |
[
"Why do we kiss?"
] | [
false
] | What's the attraction it kissing. Has it just become a common thing that people do that everyone does it, or is there something to it? | [
"To summarize answers from the links people provided:",
"People kiss because social bonding between adults in humans and other social mammals is built off of the same basic neurological and hormonal framework which bonds mother and child (the most \"primitive\" and basic social relationship shared across mammals)... | [
"Heh, I'll have to mention that to my prof. I don't know that it has been studied.",
"I will tell you that the birth control pill changes the preference. Women on birth control (and pregnant women, due to the somewhat similar hormonal profile between the two) prefer the smell of t-shirts (I kid you not, that's ... | [
"\"Human females (maybe males too, not sure if it was tested) have a subconcious ability to detect MHC compatability and prefer potential mates with a good match. This is the \"chemistry\" in kissing.\"",
"I wonder... does this involve only female / male kissing or does this come into play when lesbian or bisexua... |
[
"Why are anti-parasitics (ie hydroxychloroquine, remdesivir) tested as COVID-19 treatment?"
] | [
false
] | Actual effectiveness and politicization aside, why are anti-parasitics being considered as treatment? Is there some mechanism that they have in common? Or are researches just throwing everything at it and seeing what sticks? Edit: I meant Ivermectin not remdesivir... I didn't want to spell it wrong so I copied and pasted from my search history quickly and grabbed the wrong one. I had searched that one to see if it was anti-parasitics too | [
"In a basic sense, usually because they’ve been shown in cells or in animal studies to either block binding of a virus to a cellular receptor (zinc for example), inhibit cellular proliferation/ cause cell death (which gives the virus limited resources for infecting new cells and therefore proliferating), and/or it ... | [
"Cells in a dish don’t always behave exactly how they do in the human body and sometimes in vitro studies that show beneficial results use doses of compounds that are not feasible in humans or animals.",
"A classic example is that ClF3 is an absolutely awesome in-vitro anti-biotic. You can be 100% sure nothing wi... | [
"Chlorine trifluoride is ",
"fun stuff",
":",
"It is, of course, extremely toxic, but that’s the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and ",
", not to ment... |
[
"Do photons (ie. light) possess the property of inertia, or inertial mass?"
] | [
false
] | It seems surprisingly difficult to find an authoritative (layperson-friendly) answer to this. It's pretty obvious that a hypothetical box of photons will have a greater inertial mass than an identical-but-empty box, but can light be said to have inertia? | [
"To talk about photons/light, it is necessary to invoke relativity. We can't use Newtonian mechanics to answer questions about things that move at the speed of light.",
"In relativity, photons are massless particles, where 'mass' is defined to be 'the energy that an object has at rest.' Photons are never at rest,... | [
"Alright, that makes the whole 'yes and no' aspect of it clearer. Thank you muchly!"
] | [
"As an add-on, because photons do have measurable inertia, this exact concept is what propels the various Solar Sail projects going on for next generation spacecraft. The Planetary Society, NASA, ESA, and JAXA all have craft planned or launched to take adfantage of the \"pressure\" from the sunlight! If you've been... |
[
"How come some illnesses are species-specific?"
] | [
false
] | For example, I can't catch kennel cough off of my dog, or FIV (kitty AIDS) from my cat, or shope papilloma virus from a rabbit. Why not? What is it about human cells that makes it so the viruses/bacteria that cause these diseases can't flourish? | [
"A great deal of it has to do with the difference in cell machinery. Think of a human cell like a machine, and a cat cell like a similar machine but with different parts. A virus that infects a cat works by using cat specific parts to replicate itself - the whole point of a virus's existence. When that virus comes ... | [
"This is correct. Most viruses evolve very closely with their hosts, and as such become dependent on specific host proteins for entry (receptors, as you mentioned), viral replication, and egress. There are a vast variety of species-specific intracellular host proteins, like transcription factors, that are necessary... | [
"Thank you. Excellent answer."
] |
[
"How does petrol \"get old\" in a container?"
] | [
false
] | Discovered today that petrol, even if it's in a decent container, gets "old" and loses combustability. You can also get additives to prevent this. What's going on and what do the additives do? | [
"First of all, some of the more volatile components tend to evaporate over time, unless you have a metal container that is well sealed. This leaves behind the heavier fractions that also tend to have a lower octane rating, and of course have a harder time forming the proper fuel/air ratio in a carburetor.",
"Stal... | [
"Awesome explanation. Thanks so much!"
] | [
"It is my understanding that the octane rating is raised rather than lowered as the heavy elements are less prone to pre-detonation and thus less volatile. Am I correct in this? Additionally, over time water is drawn in with oxygen further thinning the mix. "
] |
[
"If Satellite TV goes out when it rains, what about 5G \"millimeter wave\"?"
] | [
false
] | If you follow sites like DSLReports, you may know that Verizon is wanting to use "millimeter wave" and 5G to do home broadband rather than fiber or upgraded DSL (like G.fast). Verizon's 5G broadband uses 28 and 39 GHz bands. It is very well known that Satellite TV , especially because of the use of the Ku-band in the ~12GHz range. Would millimeter wave wireless also go out when it rains because of the use of higher frequencies than Satellite TV? | [
"I've never seen satellite go out from rain. I only see it go out from snow after the snow has built up on the dish. The combination of the extra weight on the dish affecit it's focus, and the slight weekening of the signal because of the built up snow. ",
"Soure: Installed satellite for over 5 years. Been on man... | [
"the signal does get worse from strong rain (stormy weather, thunder and lightning type strength) to the extent where it may break down completely. weaker signals suffer more of course.. if you have a strong signal you will rarely have problems with it. but for instance when you're in mainland Europe the signal fro... | [
"I have seen them go out when the dish, satellite, and sun are all in a line. The thermal noise from the sun can overwhelm the sat signal."
] |
[
"For feral children/adults, how does their \"inner monologue\" sound when they are thinking? Would it be a visual step by step process instead?"
] | [
false
] | null | [
"I don't think that's exactly the same though, because many deaf people know sign language and the structure of language has to affect their \"inner monologue\" in some way versus feral people, who haven't learned language. Is there any validity to that?"
] | [
"Radiolab did a fascinating story on this (kind of) a while back.",
"http://www.radiolab.org/2010/aug/09/"
] | [
"Keep in mind this subject is difficult to study and highly debatable. Any research someone presents you with is almost guaranteed to have reasonable arguments against it and in favor of another explanation. I say this only because, as far as psychological concepts are concerned, I see all too often (almost every t... |
[
"Which sicknesses have been with humanity the longest?"
] | [
false
] | Things like organ failure have been with us since we have had those respective organs; but do we have any idea which bacteria, viruses, pathogens, auto-immune, etc. have been with humanity the longest? I feel like there is more to the question here than I am capable of asking; so please elaborate in your answer. | [
"There are a few areas in your second paragraph that are misleading. First \"any particular virus or bacterium -- is quite recent because we can develop defenses against them\" just isn't true. There are many bacteria and viruses that are rather old. Before we eradicated it smallpox was a great example of a viru... | [
"There are a few areas in your second paragraph that are misleading. First \"any particular virus or bacterium -- is quite recent because we can develop defenses against them\" just isn't true. There are many bacteria and viruses that are rather old. Before we eradicated it smallpox was a great example of a viru... | [
"I assume you meant not unusual in the third sentence?"
] |
[
"I've heard a lot about String Theory as a 'theory of everything'. What theories haven't I heard about?"
] | [
false
] | null | [
"Thousands. There really is a sea of generalizations and alternative theories that can't yet be verified experimentally. For example, my bachelor thesis was (in part) about ",
"f(R) gravity",
", a theory that generalizes our accepted, experimentally verified theory of gravity. You might have heard of ",
"Supe... | [
"There isn't really anything else that proposes a ToE. String Theory isn't some crazy invention. If you start with the Standard Model and try to expand it to start including gravity or to unify the Strong interaction with the Electroweak interaction, you inevitably come across failed theory after failed theory afte... | [
"Well, I can try, but I am not very good at it, so I'm sorry in advance. I'm basically answering your question only in the last two paragraphs - all the stuff before is (necessary) prerequisites.",
"One of the most wonderful things you learn very early when studying physics is the ",
"principle of least action"... |
[
"Student teacher (physics) with a request"
] | [
false
] | null | [
"Can you explain further? I'm not sure for what type of suggestions you're asking. I imagine you want to use a story involving science?",
"Edit: that is a ",
" story, by the way. Bohr was a marvel."
] | [
"Well I have to tell a story which is somehow connected to the current curriculum (electricity). It must also have some kind of dialogue in it (so I can use different kinds of voices). "
] | [
"Looks like your post was deleted. I was worried about that, although I must say I disagree with the mods on this one.",
"There must be some stories out there, but my google-fu and recollection fails me. Best of luck!"
] |
[
"If susceptibility testing is already difficult and sometimes highly specific for patients who aren’t immunocompromised, how do doctors select antibiotics and antimicrobials for burn victims and patients who have a severely compromised immune system?"
] | [
false
] | Is there a gauntlet of drugs that are used against common skin or nosocomial flora that doctors administer until the skin or immune system can kick back in? For background for anybody reading: We test susceptibility for antibiotics by exposing bacterial cultures to samples of specific antibiotics to see what happens to the bacteria in the plate. When you expose a bacterial colony to an antibiotic it is susceptible to, there will be a reaction that tells us that the doctor can use that antibiotic on a patient to treat an infection. The reason I am asking this question is because I’ve never worked in the ER or burn unit, only small labs. And I’ve seen how in Micro it’s necessary to run multiple tests just to determine the proper antibiotic for a single infection. But for a system wide entry wound like a massive burn, I imagined it must be grueling to find a proper treatment when bacteria come in from every surface possible. | [
"Doctors use broad spectrum antibiotics that are active against the bacteria that typically cause an infection in that area.",
"Then based on culture data, they can narrow or broaden their coverage as needed.",
"Susceptibility testing is no different for a competent or immunocompromised patient, because we're t... | [
"Cultures help identify the bacteria, which doctors will use to adjust their antibiotics based on which antibiotic typically cover that species.",
"Then susceptibilities help more so that they know for sure which antibiotics should work.",
"It's all important."
] | [
"For immunocompromised patients, the gauntlet is all the more difficult because the damage can be caused by culture-resistant bacteria or fungi. Burns is different because infections are almost always caused by bacteria which have translocated from the skin.",
"Edit: source in reply comment as the above is oversi... |
[
"A few questions for aeronautical experts or pilots regarding Colgan air Flight 3407 2009 disaster."
] | [
false
] | Looking at the NTSB report and wondering a few things I cannot easily find answers to. Just to satisfy my curiosity: 1- On approach the plane reduced speed from 180 knots to 135 in less than 20 seconds. The flaps were at 5 degrees. There is no indication why the plane lost so much speed so quickly. Any ideas on why that would be? (pilot error, ice buildup, wind conditions etc.) 2- The plane began its stall at 2300 feet and the stick pusher mechanism activated, sending the nose downward. If the pilot had not over-ridden the anti-stall device by pulling the nose upward could the plane have recovered from the stall at that altitude? 3- The co-pilot retracted the flaps and landing gear when the captain attempted to pull out of the stall, did this contribute to the accident in any way? 4 The report says one cause of the accident was "the flight crew’s failure to monitor airspeed in relation to the rising position of the lowspeed cue". What exactly does "rising position of the lowspeed cue" mean in layman's terms? | [
"Private pilot here, I haven't read the full NTSB report yet, just my speculations:",
"It is true that that kind of plane does not slow down easily, however with flaps and landing gear down, if the pilot pulls the nose up hard, you can lose that much speed quickly, or if you meet a strong windshear or thunderstor... | [
"You did such a great job there is no further need for further comments most likely. Thanks."
] | [
"naughtius answered everything pretty well satisfactory I think, but if you're interested in seeing a recreation and analysis of the accident, the Canadian documentary series Mayday ",
"did an episode on the crash of Colgan Air 3407",
". Not sure if they video link will work outside Canada or not, though."
] |
[
"How would the BIPM proposed change in the SI units affect the numerical value of the gravitational constant?"
] | [
false
] | One consequence is that the numerical value of the Planck constant in the new units will be exact (as will several other physical constants). What impact might this have on the gravitational constant? Will its value be exact as well, or will it still be experimentally determined? | [
"The new SI will not have any significant impact on Newton's Gravitational constant G. It will remain an experimental constant. Two things to consider. First unit realizations necessary for G are the kilogram (kg), the meter, and the second. The second and the meter will not change in the new SI, and the kg will ch... | [
"Excellent. Thank you. Since I have you here, maybe you can answer another: in the new SI system, the physical constants are defined explicitly, not the units. The units are then defined as whatever gives those numerical values to those physical constants. The new SI system consists of seven explicit definition... | [
"The second will stay as it has been, in terms of the hyperfine Cs 133 transition. Fixing the Planck constant effectively gives you the Kilogram. Fixing e gives you the Coulomb. Fixing k (Boltzmann) gives you the Kelvin. Fixing the Avogadro constant N_A gives you the mole. The meter is unchanged since the speed of ... |
[
"What makes up dust?"
] | [
false
] | Do people label any non-homogeneous suspension in air dust, or is there a specific type of dust? Everyone uses the term, but no one clarifies what is contained within it. | [
"The common explanation is that dust is mostly dead skin cells, but in abandoned houses, there are layers and layers of dust and no human being has been living there for a very long time, so in this particular case what is dust made up from?"
] | [
"Mostly dead skin cells."
] | [
"That only applies to dust found where humans and animals frequent. Dust at a construction site or in a cave is not made of dry skin flakes."
] |
[
"How do hydrogen bombs work and how does the difference in design contribute to it being superior to uranium-based atomic bombs?"
] | [
false
] | null | [
"I'd recommend reading up on the ",
"Teller-Ulam design",
".",
"A relatively small (in explosive yield) nuclear device called a \"primary\" is used to generate an extremely high-temperature (hundreds of MegaKelvin) photon gas, which can then be used to implode one or more \"secondary\" stages.",
"The second... | [
"I would just slightly expand upon this excellent answer to add that fissile material is very, very expensive to produce. In fact, access to sufficient materials is the biggest impediment to building nuclear explosives.",
"Lessening the amount of these special nuclear materials needed to produce the required expl... | [
"To further add: pure fission bombs are extremely inefficient. It's estimated that, at best, 1kg of the 65kg of 80% (average) uranium-235 in Little Boy underwent fission. The rest was just scattered into the atmosphere.",
"Fusion increases yeild by increasing efficiency and thus power, and makes the bomb \"cleane... |
[
"Assuming our ears and mouths could keep up, how many different conversations could a human brain have at one time?"
] | [
false
] | I was watching Futurama's Beast with a Billion Backs and the alien had conversations and experiences with billions of people at the same time. So, assuming that our mouths and ears could handle the physical work, how many conversations, thought processes, etc. could a human brain handle at one time? | [
"I struggle mightily with one."
] | [
"What quality of conversation? How different of a subject matter? There are a LOT of variables that significantly effect this. ",
"Generally, human brains aren't really good at true multitasking, we do more of a fast-switching pseudo-multitasking that degrades with each additional task we take on. "
] | [
"From my experience most people do, although they don't realize it."
] |
[
"How do they start up a nuclear reactor?"
] | [
false
] | Was looking through YouTube and saw this video Was wondering what exactly is going on in it. What are they starting up? How are they starting it up? Is the blue from the reactor it self or just lights they have? | [
"The nuclear fission reaction works by splitting atoms. Typically we use Uranium-235 for most reactors, although Plutonium-239 and Uranium-233 (bred from Thorium-232) can also be used.",
"To split the atom, we provide it with neutrons of the appropriate amount of energy. The atom absorbs the neutron, becomes unst... | [
"In the video link and other material I could find, they talk about pulse lengths much shorter than seconds. I'd be surprised if they weren't using TRIGA fuel and controlling the pulsing with the removal rate of the rods. I've known of several reactors used for neutron research like this one that used TRIGA fuel to... | [
"Looks like they use a special UO2-BeO fuel in the ACRR."
] |
[
"Why Is Summation of Velocity Vectors Valid?"
] | [
false
] | I've seen in several Math and Physics texts questions like, "If a boat goes blah blah in still water and is placed in a countervailing current of blah blah, what is the resulting speed?" or "If a plane has mupmup velocity vector and facing a wind vector pumpum, what is the true velocity vector?" and is invariably answered by summing the vectors. Why is this valid? I have absolutely no training in Physics and just a pretty decent understanding of Math. A priori, I would not have thought that the velocity vector would be the simple sum, especially when the mass of one object is substantially greater than the fluid it's pressing against. Is it just that we've empirically found that we get a roughly correct answer by doing this? | [
"There is a major assumption that the books should be explicit about, but they often times are not. That assumption is that the airplane/boat is in a steady state. ",
"Most likely what is confusing you is that you are imagining a boat tied to a dock (or something similar) and then becoming untied. Obviously, the ... | [
"That makes a lot more sense, thank you!"
] | [
"how much training do you have in math? i ask as a way of gauging how to phrase my response to your question (if you still need an answer)"
] |
[
"Will we all eventually be the same skin colour?"
] | [
false
] | With humans travelling all over the world very frequently, and other such activities, is it possible that we will all evolve to have the same skin colour? | [
"(Not a biologist, am a physicist, took many biology classes while getting various degrees, would invite someone with a biology background to add to this or point out any errors in my understanding)",
"For a long time you would see articles cropping up predicting the end of blue eyes or the end of red hair or oth... | [
"Are you sure he's your father?",
"Just kidding. Your father is probably a heterozygous for dark hair and brown eyes (do either of his parents or grandparents have blond hair and/ or blue eyes?) and his recessive alleles were passed on four times. That's pretty incredible. "
] | [
"What the fuck are you saying? The reason Northern Europeans have a strict immigration policy is because they have welfare systems that they can't afford to strain anymore with the waves of immigrants that come for the social security.",
"\"They don't get a lot of visitors up there\" - What the fuck? Are you 5?",... |
[
"How is it that plastic doesn't occurr naturally in the universe?"
] | [
false
] | With the seemingly infinite combinations of elements and conditions, why isn't there a plastic planet? | [
"The reason plastic isn't known to be naturally occurring is probably because it's made of a lot of long hydrocarbon chains. The hydrocarbons hold a lot of energy in their bonds. Have you ever burned plastic? Have you seen the energy it releases when it burns? Take another substance made of hydrocarbons: petroleum.... | [
"Well, given this logic, plastic ",
" arised naturally from our hands."
] | [
"why isn't there a plastic planet?",
"I think we are having a slight misunderstanding in how infinite works.",
"If you put all the parts to say a motorcycle in a box, shook the box up, and opened it expecting to find a motorcycle, it doesn't matter how many times you do it. You aren't ever going to get the tor... |
[
"Is the size of an anechoic chamber important? How tiny could you make it until it would stop working?"
] | [
false
] | I would like to build one myself, maybe even one with the size of a shipping box. would that still work? | [
"This is not completely true,because as the chamber gets smaller your body makes up a larger part of the surface inside, leading to more reflections and a less quiet chamber. Soundproofing panels also aren't perfect, they reflect a little bit of sound, and the closer (to you) they are the more of that reflection s... | [
"It depends on what you are using it for, and what your requirements are.",
"If you want to be measuring in the far field of a source, then you need to be measuring at a distance greater than D",
" / (4 * lambda) where D is the size of your source and lambda is the wavelength of the sound. So your chamber needs... | [
"That will still work. Anechoic chambers are designed to keep sound from bouncing off the walls, and there's no reason that would be less effective for small rooms. "
] |
[
"When, where, and how did warm-bloodedness evolve?"
] | [
false
] | I had a showerthought the other day that the ability to maintain body heat seems like a huge leap forward. How did it spread throughout the world? | [
"According to an article in the journal of anatomy on ",
"www.ncbi.nlm.nih.gov/pmc/articles/PMC1328175/?page=1",
" it goes on to say that the creatures who could limit the fluctuation in their body temperature in spite of the variations of the external temperature had the best chance of survival, reproduced mor... | [
"Marine mammals originated from terrestrial mammals, which are endothermic. Ectothermic species exist in niches where the advantages of ectothermy (eg. lower metabolic requirements) outweigh the disadvantages (eg. reliance on external temperature)."
] | [
"There ya go! That’s a complete explanation! But just be careful, if your saying the advantages of ectothermy outweigh endothermy than we would likely see most animals be ectothermic in areas where lower metabolic requirements are required ( sloths are a good example, although poor thermoregulators and they have a ... |
[
"If Uranium-238 decays by alpha emission, does our current science say antiuranium-238 would emit antihelium?"
] | [
false
] | null | [
"Yes, it should."
] | [
"The shortest answer I've ever seen on this sub."
] | [
"To add more, the strong and electromagnetic forces both behave the same if you exchange all particles with their antiparticles. These are the forces which are relevant to alpha decay.",
"If the question had been about a beta decay instead (the weak force), then there could be small differences."
] |
[
"Is the moon's perigee always during the full moon? If not, why are tides considered to be higher when the moon is full?"
] | [
false
] | As per the title. I've read conflicting articles on the subject and was wondering if anyone here has the knowledge to clear this up? | [
"No, when the moon is full at perigee it is called a supermoon. The most recent occurrence was on January 30 of this year.",
"Tides are caused by the combined effect of the moon's gravity, the sun's gravity, and the rotation of the earth. The tidal effect is amplified when the sun, earth, and moon are aligned, as... | [
"right, that makes a lot more sense. So a new moon also causes a bigger high tide and its potentially bigger than a full moons tide because the sun and the moon are on the same side of the earth?"
] | [
"Yes, a new moon works the same way. This link has some good diagrams and explanations: ",
"http://oceanservice.noaa.gov/education/kits/tides/tides06_variations.html"
] |
[
"AskScience AMA Series: Geology and Geosciences"
] | [
false
] | We are going to have a joint AMA series today that will span the subjects of Tectonic geology, structural geology, petroleum geology, geochemistry of petroleum and of oceans, geophysics, volcanoes, earth structure, and biogeochemistry (sorry if I've left some out). We will have people contributing from academic backgrounds, and oil-industry backgrounds, so all questions are fair game! I would also like to point out that a few of the mods and some panelists have been invited to contribute to a class-room like blog, where any questions that are received will have an entire blog dedicated to it, explaining the question and hopefully leaving you with more, it is located . It is still in its infancy, but it will take off this week. If any of the panelists are also interested in contributing, please PM me. | [
"So, there are a few different types of extensional basins, but we'll go into the most simple one and probably the most prolific mechanisms. Here is a quick reference scheme for an ",
"extensional basin",
"We can take for example the Black Sea. The Black Sea was formed as an extensional basin by the interaction... | [
"So, there are a few different types of extensional basins, but we'll go into the most simple one and probably the most prolific mechanisms. Here is a quick reference scheme for an ",
"extensional basin",
"We can take for example the Black Sea. The Black Sea was formed as an extensional basin by the interaction... | [
"I'll reply to the second question and hope that other geologists come in and express their opinions on the others: ",
"If I were to do a 30 minute presentation on anything, it would be how mountains and basins are formed. I find it very fascinating that a lot of people (vast majority of people) live, work, play ... |
[
"Can neutrinos interact with each other?"
] | [
false
] | They barely interact with standard matter. | [
"It is expected in the Standard Model that neutrinos interact weakly with each other through the Z boson. However, these interactions are so rare and weak that they have never been observed, and most of the literature I looked through is basically analyzing astrophysical data to see ",
" evidence of their interac... | [
"To add to your answer (which is good btw!):",
"The Z boson of the weak force could be produced by a neutrino anti-neutrino interaction, but the \"cross section\" of the interaction would be tiny. Partly because neutrinos have a tiny mass compared to the Z- roughly 11 orders of magnitude different I think? "
] | [
"If you had a neutrino emission event as strong as a supernova, but without all the other matter, how close would you have to get for it to be essentially opaque to incoming neutrinos due to interactions?"
] |
[
"Do taller / bigger people live shorter lives the way great danes live shorter lives comparative to other dogs?"
] | [
false
] | null | [
"Pretty much yes, this is the case WITHIN most species in fact. Interestingly, the opposite is true when comparing ACROSS species, where larger generally means longer life.",
"There are some hints of this being true in humans from the fact that women are smaller and live longer than men. Japanese populations comp... | [
"Would this suggest that supplements that help produce hgh in weight lifters or other athletes can actually lessen that person's life expectancy? "
] | [
"It's not rly clear exactly how it works, but it's known that reduced signaling in the IGF/GH axis and other aging interventions (rapamycin, calorie restriction, etc) seem to slow age-associated disease progression across a number of organ systems, extending both average and max lifespan. ",
"There are many other... |
[
"Noob Question about virus, Why there is no vaccine for HIV or any sexually transmitted disease?"
] | [
false
] | null | [
"HIV is tricky for many reasons: it infects a part of the immune system responsible for clearing it from the body, it genetically inserts itself into the host cell, and it mutates very rapidly. ",
"This site",
" has a good laymen-level summary of HIV vaccine development.",
"The hepatitis B vaccine and the HPV... | [
"The coolest thing about the HPV vaccines is that they are also essentially a vaccine against cancer! The Gardasil vaccine protects against strains 6, 11, 16, and 18. The last two of which are responsible for the vast majority of the cases of cervical cancer and anal cancer! HPV can also cause cancers in the vulva,... | [
"Yes. HPV can be spread by men/people without vaginas, so everyone should be getting it"
] |
[
"Just observed a bee chew on wood and took off, why?"
] | [
false
] | [deleted] | [
"You have probably seen some wasp species, as honeybees don't really collect wood and other bees like carpenter bees may tunnel in wood but don't really collect it and take it somewhere else. But there may also be other solitary bees that do collect wood, that I do not know about. Wasps however, are often seen coll... | [
"polistes is exactly correct. A variety of wasp species collect small pieces of wood and chew them into pulp which then is built up into a nest. It's similar to the concept of paper mache.",
"If you youtube \"wasps collecting wood\" there are a variety of videos showing and explaining just that. ",
"Way to be o... | [
"In case OP is wondering, this guy is talking about ",
"carpenter bees",
", a type of bee that chews holes into wood to build its nests. They're bigger than your standard bumblebee and have shiny black abdomens, instead of the furry yellow-and-black of a bumblebee. "
] |
[
"Does lead absorb radiation, or deflect it?"
] | [
false
] | I've always wondered this. Does lead somehow absorb the radiation from Xrays for example, or does it reflect it back? And if it reflects, is lead the only element capable of reflecting it? | [
"The exact interaction that occurs at the atomic level is actually ",
"dependent on the energy of the photons and the atomic number of the shield",
" (for lead Z=82). You can get ",
"Photoelectric interactions",
", ",
"Compton Scattering",
", or ",
"Pair Production",
". ",
"In other words, lower e... | [
"All radiation is basically energy. If it is Photons (ie xray, gamma, microwave range what ever) it is just energy. If it is particle radiation (Betas, Alphas, Neutron) then it is a particle with a very high Kinetic Energy. So basically the shielding material you use for each type is picked based on the type of int... | [
"think of the radiation as light, which is all it really is.",
"Only gamma-radiation is light. Alpha- and beta-radiation is not."
] |
[
"If a baby is born premature 7 months in the pregnancy after a month is it going to be more or less developed than if it was still in the womb?"
] | [
false
] | Is it going to be bigger, in terms of body weight and rate of growth? Is it going to be stronger? Will its cognitive development start as if it was born after a complete pregnancy or no? Basically after a month will it be able to react to stimuli as a baby that did 9 months in the womb and then a month out or will it behave as a baby born at 8 months? | [
"It probably depends on which outcome you're measuring, but there are likely to be some differences. For things like lung development, they won't get their own surfactant until the roughly equivalent time they would have started to produce it in the womb. For other things, there could be some functional adaptations... | [
"I see that in a lot of my children clients who were born premature. Many of them end up with Retinopathy of prematurity, which often causes vision loss. I didn't know it was a gene expression thing that made the oxygen less toxic, though. ",
"https://en.wikipedia.org/wiki/Retinopathy_of_prematurity"
] | [
"It's very possible, neonates inside mom don't have any where near as much to worry about. All they need to do is grow and move. Being early baby would need to stress about learning to eat early, his body has to process food now, he has to breath on his own, he is interacting with people, and lights are bright. All... |
[
"Do the good bacteria in probiotic drinks and yogurts multiply as time passes? If so, does that mean we should wait as soo as possible before consuming them to get the most of it?"
] | [
false
] | null | [
"Nah, they are freeze-dried (that's what turns them into powder) until they are consumed. In fact, the bacterial count goes down, not up, so theoretically it would be better to start using them earlier rather than later. "
] | [
"Bacteria can survive freeze drying and will be 'reactivated' upon rehydration (though the process will kill at least some of them off). ",
"As to why they won't multiply particularly well, these strains are happiest at roughly body temperature. That means all their enzymes and biological processes work best at a... | [
"It doesn't kill them. It puts them in a dormant state until they reach the body. It's a lot like when able bacteria form endospores due to lack of nutrients. They stop metabolic function, but stay alive. "
] |
[
"I've never been able to swallow pills. Does crushing or chewing pills make them less effective than those swallowed whole?"
] | [
false
] | [deleted] | [
" It can be incredibly dangerous to modify the delivery system of certain medications and it's very important to discuss this with your pharmacist and physician. "
] | [
"(LAYMAN)",
"It depends on the pill. When it matters, the instructions that come with the medication will usually specify \"do not cut or crush\".",
"The reason it sometimes matters is some pills have special coatings that cause them to be released at a given rate or at a specific part of your digestive system... | [
"Pills are formulated to be taken whole and complex compositions ensure release of active components where it is supposed to be.",
"OP I'm assuming that you are young (16-21), you should very much get over your aversion of swallowing pills because over the long term you will have to take many. Swallow with a gul... |
[
"How do I calculate how a branch bends under its own weight?"
] | [
false
] | null | [
"You are asking how straight segments bend with the caveat that they can't bend. This question is fundamentally flawed.",
"If you want to know how an object bends under its own weight, I suggest reading a text on elastics. A typical first chapter will describe 1-dimensional elastics and should derive an equation ... | [
"As I said, \"bending joints\".\nAlso, \"find the shape\" implies that you're suggesting a method for finding curving segments, which I have made incredibly clear is not what I want.",
"It's like you didn't even read what I said."
] | [
"I did read your post. I addressed the fundamental flaw in my very first sentence. If only portions of your rod are deformable, then the same reference I gave can explain how to handle that, a suggestion implied by the second part of what I wrote.",
"Cheers."
] |
[
"If a plane flies along a great circle - does it turn?"
] | [
false
] | If a plane is flying between 2 points along the path of a great circle, is actually flying a "straight" line between the two points, which looks curved on a projection of the globe on a 2D surface; or would the pilot actually need turn the plane in flight to follow the curve? I'm pretty sure it's the former. | [
"Straight, although in reality the plane is turning \"down\" the whole time. :)",
"(And let's not get started about the rotation and motion of the earth, since I assume you're talking about a case where we ignore those.)",
"But really, the equator and lines of longitude both form great circles, and on some map... | [
"That is true if you do not care where you end up. Unless your destination is the antipode, the three points (start, end, and center of the earth) have exactly one plane that includes all three."
] | [
"Thanks. Thought so but wasn't sure. "
] |
[
"How did the horseshoe crab, a living fossil, survive ocean acidification of the climate event known as, Paleocene-Eocene Thermal Maximum (PETM), a period that exhibited large amounts of carbon, which occurred 56-58 million years ago?"
] | [
false
] | The Paleocene-Eocene Thermal Maximum (PETM) is studied to draw corollaries to modern day global warming. The horseshoe crab has fossils dating back 450 million years ago. | [
"Horseshoe crabs are pretty tough, they made it through the end-Permian extinction and the K-T extinction that wiped out the dinosaurs. They are apparently quite capable of continuing to form shell even in acidified oceans (which isn't too surprising, lots of arthropods form hard shells in fresh water environment... | [
"The main distinction is that carbon dioxide levels are rising at least 5 times faster today than 55 million years ago. As a result ocean acidification is rising 10 times faster, and projected to reach much higher levels than at any time in the last 65 million years. As catastrophic as PETM was for bottom feeders, ... | [
"Just as a general point, the term \"living fossil\" is a bit misleading. All it means is that a living species looks very similar to fossils, but it doesn't mean that living species has remained completely unchanged for millions of years. Natural selection will always apply so the horseshoe crab could have gone th... |
[
"AskScience AMA Series: We are women scientists from the Homeward Bound expedition, recently returned from the inaugural voyage to Antarctica! Ask us anything!"
] | [
false
] | Hello ! is a ground‐breaking leadership, strategic and science initiative and outreach for women, set against the backdrop of Antarctica. The initiative aims to heighten the influence and impact of women with a science background in order to influence policy and decision making as it shapes our planet. The inaugural 2016 voyage took place from 2 - 21 December 2016 and was the largest‐ever female expedition to Antarctica. We care about science, the concerns of others, and we think science can unite us towards seeing and managing the planet as our global home. Answering questions today are 5 participants from the inaugural Homeward Bound expedition: Heidi is an environmental scientist, an explorer, and a science communicator, sharing her passion for science with others. She is an , Colorado. She studies how environmental changes affect mountain watersheds and Arctic systems and their link to our well-being. and featured in the , including the . Find her on social media and Medium.com @heidimountains. is a current PhD student in the program at the University of Minnesota, researching the intersection between climate change, biodiversity conservation, and women's justice. She holds a Bachelor's degree in environmental policy from St. Olaf College and a Masters in Biodiversity, Conservation, and Management from the University of Oxford. Previously, Ms. Christianson worked in the U.S. House of Representatives writing and advising on energy and environmental legislation, for Ocean Conservancy advocating for science-based marine policy, and held the position of Vice President of , a non-profit organization working to empower women to become leaders in the environmental field. A 2016 Homeward Bound participant, Ms. Christianson was enthralled by Antarctica, and inspired by the 75 other women striving to create a global network of female change-makers. is a penguin expert, TED speaker, and author of the award-winning book, . She lectures internationally about penguins, and is a sought-out expert on radio and TV, including and CNN. A participant on the inaugural Homeward Bound expedition, she returns to Antarctica next year as a . A four-times TEDx speaker, about saving 40,000 penguins from an oil spill can be viewed on TED.com. She is on Facebook, Twitter, and LinkedIn as The Penguin Lady. is an evolutionary biologist and recently submitted her PhD thesis to the at in Townsville, Australia. Her research questioned what constitutes a species, highlighting the importance of animal behavior to the outcomes of hybridization, a common and significant evolutionary phenomena where closely related species interbreed. on coral reef fish using behavior and genetic tools provides novel insights into the ecology and evolution of species. She is passionate about the marine environment, women in science, and diving. She joined the Homeward Bound network in 2016 to build future collaborations and learn within a program aimed to elevate each woman's leadership abilities and capacity to influence in the future. This was highlighted in an article written for . Connect with her on twitter at @AshtonGainsford. , is a climate scientist with specific research interests in climate variability and change, alpine hydrometeorology and Antarctic meteorology and climatology. She works for (a government-owned renewable energy company operating in Australia's alpine region), and specialises in understanding weather and climate processes that effect water resources in the Australian Alps. Johanna maintains an affiliation with the following her PhD on Antarctic meteorology and climatology. She wants to live in a world where quality science is used to make more informed decisions in the way this planet is managed. She thinks Homeward Bound is a pretty inspiring initiative to help get more women to the decision-making table. See for her publications, or find her on twitter @johspeirs. | [
"Antarctica was beyond what I expected in so many ways. This coming from a person who thought it would be Greenland-like just icier. I've spent whole summers in Greenland studying polar deserts and their response to climate change. So how is Antarctica different? I knew there would be very few plants - just two spe... | [
"We all know science isn't really about preconceived notions but were there any discoveries or experiences that went against what you'd expected to see, or anything that went beyond what would be expected?"
] | [
"How cold is it there really? This may seem like a childish question but hear me out. I live in Pennsylvania and it gets pretty cold here. Like face-hurting wind cold. And I'm pretty sure it's gets colder in other parts of America but I can barely handle here. Was it the type of cold that made you immediately regr... |
[
"How can an object have zero net torque, yet be able to turn?"
] | [
false
] | null | [
"So I am not sure if I am interpreting your question correctly. Do you mean how can an object that is rotating have zero net torque?",
"The answer is constant angular velocity. Torque is a force applied across a distance (the cross product of force and distance). Force is mass x acceleration, and acceleration is ... | [
"Roughly speaking, you can think of torque as the angular analogue of force. ",
"Translating your question into linear mechanics, it is equivalent to asking",
"\"How can an object have zero net force, yet be able to move?\" ",
"The answer is that it is already moving. ",
"Now, it's possible that you're aski... | [
"Are you asking how to change direction in space while maintaining zero total angular momentum? (This is not exactly what you asked, but it's a pretty common question, so I'm wondering if it's what you meant.) It is possible to do this within a closed system---that is, without using rockets. ",
"This article",
... |
[
"Can two people repopulate the Earth?"
] | [
false
] | Would it be possible for a single male and female to slowly repopulate the Earth? (disregarding some catastrophic event). | [
"You asked if it is possible. Perhaps, but it is very unlikely. A breeding population of two humans would lead to genetic problems, which would very likely lead to a high rate of mortality for offspring for many generations. A lack of genetic diversity could also lead to the population being susceptible to disease,... | [
"It's important to remember that minimum viable populations* and inbreeding depression are not hard limits, they just make it more difficult for populations to become established. Two people could most certainly repopulate the planet. Islands have frequently been colonized by animals with populations this small. ... | [
"That isn't ",
" we have genetic disorders. (I'm not being snarky, but) the reason we have genetic disorders is because of genetic maladies, or genes that do things that we deem less than ideal (sickle cell, for instance). ",
"Can some of the disorders be traced to that bottleneck? It's possible. Some are likel... |
[
"How is a mental illness defined and differentiated from the \"normal\" spectrum of behavior?"
] | [
false
] | [deleted] | [
"1.) Yes and no. A lot of what might be classified or termed \"normal behavior\" is (not surprisingly) subjective, and is really influenced by cultural norms. And this really coincides with question 2.",
"2.) For something to be considered a mental illness it would need to be defined under the Diagnostic and Stat... | [
"To give you the short answer, if the behavior causes a severe disruption of the person's Occupational, Interpersonal, or Leisure activities, the person has a good chance to get a diagnosis. We call it the OIL, and we check a person's OIL."
] | [
"Abnormal behavior would generally be considered behavior that lies on the far ends of the Bell curve for a given population (I say this just to give you a picture of what abnormality is - I do not intend to say that all abnormal behavior is statistically at the ends of the bell curve, though it often is). Mental i... |
[
"Why is cancer often \"delayed\"?"
] | [
false
] | I recently watched and realized that cancer tends to manifest well after exposure to certain substances. This is true with many things, such as smoking, drug use, sunburns, etc. My understanding is that cancer is a mutation of cells often caused by an outside source such as chemicals or radiation. In this woman's case, shouldn't cancer have manifested shortly after exposure to burn pits? Why did it take so long, and why does this often seem to be the case regardless of the initial cause? | [
"DNA for Cell replication is happening all the time, and mutations are pretty normal. There are actually a bunch of different kinds of mutations, most of them are relatively harmless. But when you get damaged DNA via viruses, radiation, burns etc. It greatly increases the chances of more mutations happening as cell... | [
"This is a simplified view (I don't know the details either), but the transition from normal to cancerous flesh has several steps and takes time. Several ",
"biological capabilities are acquired",
" Nor is it inevitable: some heavy smokers live for an annoyingly long time. (Annoying to me, not them.) Why? ... | [
"The details will depend on the type of cancer and exposure, but the very general answer is that cancer requires multiple \"hits\", or damages/alterations to DNA, to occur. The initial exposure is just one \"hit\", and then repeated exposures, or just spontaneous mutations accumulating slowly over time, are needed ... |
[
"Are huge Saharan features caused by erosion?"
] | [
false
] | When looking at a detailed globe, there are some huge structures that look like the remnants of ancient water or ice erosion, but could also be an illusion of rock formation. A very clear example of this is a 700km by 500km "fan" straddling the Chad-Libya border. Most of Mauritania looks like it is "flowing" west to the Atlantic, and there is a large parenthesis shape ")" covering most of Saudi Arabia. What are these structures? Do they have a name? | [
"Other commenters are talking about sand dunes but I don't think that's quite what you're asking about. While it's true that sand sculps much of the topography of the Sahara you asked about the really big stuff- and I think I'll just address them individually. But first, let me mention that \"ancient\" water erosio... | [
"Thank you, yes, those are the some of features I was asking about. ",
"The Tibesti uplift is now clear to me. There are smaller NE-SE striations across, for example, The ",
"Eye of the Desert hiking area",
" which appears to be a much older outflow cone. The more I look at this, it is very complex interactio... | [
"Technically yes, mainly wind erosion and sand in the wind sandblasting hard rock away. But we have to remember that erosion can technically build structures as well because that eroded material has to go somewhere. It doesn’t disappear. These structures could be caused by erosion of large rock, or they could be ca... |
[
"Are software systems on Voyager I or other older spacecraft upgraded or improved?"
] | [
false
] | As we upgrade our technology and infrastructure in the IT world we have to flash new firmware, upgrade software/hardware, and/or perform maintenance on systems to keep them up-to-date and running smoothly. As technology improves are organizations like NASA actively making software changes on a spacecraft like Voyager I, potentially adding features or improving existing processes? | [
"In the 19",
"80's the Galileo probe had it's image software updated to allow for image compression. This resulted in the ability to transmit significantly more images using the limited bandwith available.\nTo illustrate how dangerous interplanetary software updates are here are two cases where it went wrong:",
... | [
"They can be, but you don't want to go messing around with the systems more than you absolutely need to. If you put the wrong firmware on a server's motherboard and you need to pull the CMOS battery then you can do that relatively easily—it's a headache but it'll just cost you your afternoon and, in the worst case... | [
"\"If it ain't broke, don't fix it\". Especially when it is Billions of miles from Earth and you can't \"unfix\" it."
] |
[
"Is it true that concussions and even subconcussive impacts kill neurons?"
] | [
false
] | I’ve gotten a lot of mixed info on this. I heard you don’t even need to get a concussion for an impact to damage your brain and kill neurons, is this true? | [
"You've probably gotten a lot of mixed info because there is a ",
" of mixed info out there. ",
"This paper",
" would be a good read if you want a detailed and relatively recent description of what we currently understand about concussions.",
"But, in brief, after a (mild) concussion, the changes in brain f... | [
"What about when there are no symptoms? Like in a subconcussive impact. "
] | [
"Well, if somebody's not showing symptoms, then what they skipped was the depolarization/overfiring/potassium everywhere/\"energy crisis\" part that makes it a concussion. However, the axon damage part (stretching/snapping) could ",
" still be happening. Even something as (seemingly) non-traumatic as ",
"headin... |
[
"In what manner does antimatter-matter annihilation release energy?"
] | [
false
] | Can we please consider positron/electron annihilation and proton/antiproton annihilation and their preferences to producing massive particles and massless particles? Production of massive particles aside would the reaction produce two photons of opposite momentum and equal energy or maybe a spectrum of photons mostly gamma rays? How would the spectrum of photons look like in relation to the type of particle/antiparticle interaction? | [
"Typically, when a positron and an electron annihilate, two photons are produced, each with an energy of 511 keV, the mass of the electron (times c",
" ). ",
"If the particles had significant kinetic energy before annihilating, the photons can have more energy, or other particles can be created if the electrons... | [
"The other comment already addressed the energy issue. ",
"All products in annihilation reactions will have the same quantities as the original pair i.e. All quantities are conserved. "
] | [
"Cool, thanks for finding the link for me. ",
"So I got a follow up question. What's up with the photons to the left of the 511keV part of the spectrum? Think it could be that say there is a significant difference in kinetic energy/momentum that you'd get say one photon of 510keV and another of say 514keV to make... |
[
"Could an infinite sequence of random digits contain all the digits of Pi?"
] | [
false
] | It's a common thing to look up phone numbers in pi, and it's a common saying that every Shakespeare ever written is encoded in pi somewhere, but would it be possible for every digit of pi to appear in a random sequence of numbers? Similarly this could apply to any non terminating, non repeating sequence like e, phi, sqrt(2) I suppose. If not, what prohibits this? I guess a more abstract way of putting it is: Can an infinite sequence appear entirely inside another sequence? | [
"It's a common thing to look up phone numbers in pi, and it's a common saying that every Shakespeare ever written is encoded in pi somewhere, ",
"I just want to note this this is commonly believed, but as yet unproven. A infinite decimal in which every possible digit sequence appears ",
" is called a ",
"\"no... | [
"It's any ",
" sequence of digits."
] | [
"Sure. Take 1 + π/10 = 1.314159265359...",
"or 138.594859 + π/10",
" = 138.594859314159265359...",
"etc.",
"Further, since the decimal exansion of π is non-terminating, you can't ever have a number of the form",
"some_digits,π,some_more_digits\n",
"so those are really the only options for realizing this... |
[
"Is the \"red-ness\" of hemoglobin somehow connected to its function?"
] | [
false
] | The color of blood is so impressive, is it only coincidence or somehow relevant for its function? | [
"It’s because of the iron. Red blood cells need iron to make haemoglobin and myoglobin in order to transport oxygen to various parts of the body. ",
"This isn’t the only way to achieve this though which is why horseshoe crabs have blue blood. In their case they use haemocyanin instead which uses copper which make... | [
"And the red-ness of (iron based) blood is actually connected to the amount of oxygen it carries. Blood full of fresh oxygen is bright red and blood carrying back CO2 to the lungs, so it can be breathed out, is a much darker red."
] | [
"I'm pretty sure it's because you don't have elemental iron in your blood, which is the form that iron bars are made from. Rather, you have ferrous iron oxide in your hemoglobin, which is a dark red color (the color of rust, because it is rust)."
] |
[
"Do black holes have entropy?"
] | [
false
] | [deleted] | [
"Yes, the entropy of a black hole is kA/4L",
" where A is the surface area of the black hole, k is Boltzmann's constant and L is the plank length. "
] | [
"Just wanted to emphasize that entropy proportional to surface area is the only sensible answer. The inside of a black hole is inaccessible and so, in order to conserve entropy, whatever entropy a black hole has must manifest on the surface."
] | [
"Yeah, it's the surface area of the event horizon."
] |
[
"If you include something made up into a story (of a real event) and tell it again and again, will other people who were part of it actually start to believe your version?"
] | [
false
] | I guess you'd probably have to tell the story again and again? And wasn't there something about telling stories that would make you believe that you were part of it, even if you weren't, if told often enough? Edit: Everyone, thank you so much! Your answers helped a lot! | [
"When you remember something, you aren't actually accessing some sort of data bank pertaining to that event. You're actually recreating the event from concepts within your brain that have strong connections to it. Pretty much every time you remember something, it changes, even if just slightly. So, yes, reinforc... | [
"The research on this kind of thing is pretty famous, and is in large part thanks to Dr. Elizabeth Loftus (et al., of course). Her research focussed a lot on how you can alter memories with language use and how fallible eye witness testimony is because we don't actually store things very well at the time (and so an... | [
"When you remember something, you aren't actually accessing some sort of data bank pertaining to that event. You're actually recreating the event from concepts within your brain that have strong connections to it. ",
"That's actually extremely terrifying. Do you have a source for it?, because I'd like to read mor... |
[
"Why is hair loss so symmetrical?"
] | [
false
] | Gentlemen of advanced age always seem to have very symmetrical balding patterns. Why is it so? | [
"Androgenic alopecia is thought to be caused by abundance of sex hormone (DHT) in predisposed scalps. While different distribution patterns do exist, it would be far more surprising if the pattern were not bilateral, since that would suggest a non-random distribution of hormone in the affected tissue.",
"That sa... | [
"No problem. Front to back is the other big one. Blanking on a neater name for it."
] | [
"Thanks so much! So if vertex balding is the monk style pattern, what is the other type of androgonic alopecia that Rogaine is not effective on?"
] |
[
"Hey /r/AskScience, can I get some ideas on chemistry-related cookie designs?"
] | [
false
] | [deleted] | [
"These!"
] | [
"How about Schrödinger's Cookies? You could bake cat-shaped cookies and put it them little cardboard boxes."
] | [
"And the cookies may or may not be in the box!"
] |
[
"How does convection fit into the behavior of Brownian motion? Doesn't the observation of convection contradict the Brownian motion?"
] | [
false
] | I've got a contradiction in my understandings of convection and Brownian motion. It seems to me that the assertion that gas molecules would be statistically unbiased in their direction (Brownian motion) fails to explain the macroscopic behavior of unbounded lighter molecules. For instance: why does a flame point upwards? I understand that heated gases are less dense than colder gases, of similar chemical composition, but why don't they just expand in all directions? Doesn't the Brownian model require hotter molecules to just vibrate faster, but still move in an unbiased direction? I can see why helium in a balloon would rise in an air atmosphere. Basically the pressure differential between the top and bottom of the balloon results in a net upwards force on the balloon which is lighter than the net hydrostatic pressure difference across the height of the vessel. This behavior of rising lighter gases goes funny when the container disappears and the molecules are allowed to diffuse. Can a heat and mass transfer professor help me with this conundrum? | [
"You can still have biased brownian motion. For instance, something that feels a potential in one direction but is free to diffuse in the other two directions (what you're talking about), or a brownian particle that is still under a central force (this is how optical tweezers work). Or a simple example, a small bea... | [
"Gravity. As represented in the ",
"Rayleigh Number",
". A flame in gravity raises upward. A flame in microgravity or less actually forms a ",
"ball",
" as you thought it would."
] | [
"I'm not meaning to criticize Rayleigh's work. It does fail to explain the behavior at a particle level though. I am aware that there are many macroscopic models which predict the bulk behavior of gases. My boggle is that the only microscopic model that I know of (Brownian motion) fails to explain a lot of macrosco... |
[
"Why, after Hurricane Katrina, were large masses of trees planted near the mouth of the Mississippi River?"
] | [
false
] | I've heard bits and pieces of a story that, after Hurricane Katrina devastated much of the southern states of the US, thousands of acres of trees and/or shrubs were planted near the mouth of the Mississippi river. I can't seem to be able to find much information. | [
"Trees have roots that hold the soil around them which stops wetland loss. Wetlands act as a buffer to storm surge during hurricanes. In addition, trees would poke up through the storm surge during a hurricane and knock down waves. Those waves could be breaking over the levees. "
] | [
"The Mississippi River Delta has seen alarming amounts of wetland loss in part due to sediment deprivation (resulting in subsidence), saline intrusion and land development projects. The reason this is so important is because for every ~3.4 miles of coastal wetland a storm must pass over, storm surge is diminished b... | [
"The Louisiana coast line currently loses roughly a football field of land per hour without the assistance of hurricanes."
] |
[
"Why do retroviruses have to go through reverse transcriptase to create mRNA?"
] | [
false
] | Retroviruses are a class VI virus. Their genome is positive single strand RNA (+ssRNA). mRNA is also +ssRNA. Class IV viruses are also +ssRNA and are used directly as mRNA. Whereas Retroviruses have to be converted to a double stranded DNA intermediate via reverse transcriptase and then the +mRNA is transcribed from the dsDNA. Why couldn't retroviruses be used directly as +mRNA? , class IV and class VI viruses circled in red | [
"The simple explanation is they evolved that way. We don't know enough about viruses to justify how they evolved (heck, we don't even know if they're even ",
").",
"Class IV viruses do not incorporate their genome into the host DNA. Like you said, they transcribe directly as mRNA into protein. This means that t... | [
"It's just so weird. They are both +ssRNA, so what makes them different? Oh and my professor explicitly said that viruses are NOT alive but he also included the loophole \"at least not for the purposes of this class.\" It's just odd to claim they aren't alive, what makes them less alive than a bacteria? They evolve... | [
"There's an ongoing debate on whether or not they're alive. Your professor is right though: it's much more useful to say they're non-living for the purposes of your class. Saying that viruses are alive conjures up the debate and so it's not really useful to discuss.",
"You're implying in your statements that evol... |
[
"Are there any major cases of speciation/evolution in invasive species that we know of?"
] | [
false
] | Are any invasive species known to have diverged substantially from original populations after years of isolation? Obviously evolution is ongoing and continuous but what about obvious physical differences that are already the result of a species being relocated by humans? | [
"I am not sure if you find it a \"major case\", but just in a few decades the Spanish slug(invasive land slug in much of Europe) have changed colour quite dramatically here in Denmark. When it first invaded in the late 90's it was ",
"bright orange",
", but just over the last 15-20 years it has changed to a mor... | [
"Interesting! That's exactly the sort of thing I was looking for. "
] | [
"Commenting to hear others' input, but it would seem that to be an invasive species would mean being introduced to an area with less stressors than the native environment--they thrive in the new environment as-is without pressure thereby lessening the likelihood of \"quick\" speciation."
] |
[
"My 6 year old friend wants to know: If you split one atom how big would the explosion be?"
] | [
false
] | null | [
"202.5 megaelectronvolts, or about 4.32x10",
" kg of dynamite. That is on the order of a millionth of a millionth of a millionth of a kilogram of dynamite. (This calculation assumes that the atom is U-235, which is the most common nuclear fuel)"
] | [
"Thanks. I'll tell him \"So small you can't see it or hear it but big enough to split the atom next to it.\" Would this be correct? Would the explosion be big enough to split several more atoms? How many?"
] | [
"Yes! That is exactly how atomic bombs work. The first explosion triggers 2-3 more and so on until all the atoms have been split."
] |
[
"Does everyone's intestines fold the same way?"
] | [
false
] | From dietary images to textbooks, I've seen the internal organ diagram with the big jumble of intestines. But is it random? Do intestines just kinda, grow, or is there a specific way they grow? | [
"The intestines don't grow the same way for everyone. The large intestine has a pretty specific schematic to it so that is pretty constant in everyone; however, there are many minor differences and a few major ones. The small intestines are what are really variable. ",
"When it comes to abdominal surgeries, you c... | [
"I guess I should have been more accurate with how I described it. The small intestines are connected by mesentery to the posterior abdominal wall. The mesentery is where all the blood vessels to and from the small intestine travel through. If you move aside the small intestines, you can see the mesentery coming of... | [
"..like stuffing a sleeping bag back into the pouch?"
] |
[
"Is there such a thing as objective reality?"
] | [
false
] | I know it's a vague question. But I have friends that postulate that everything is subjective, and when I bring up the laws of science they find a way to weasel out of it, mostly because I'm not knowledgeable enough to arrest them on their mistakes. Are they right? And if not, how can I make a better argument for my case? | [
"Oh I see; Well ",
"Asimov",
" had a nice answer to this.",
"My answer to him was, \"John, when people thought the earth was flat, they were wrong. When people thought the earth was spherical, they were wrong. But if you think that thinking the earth is spherical is just as wrong as thinking the earth is flat... | [
"No one actually believes that reality is subjective.",
"Even the most ardent sophist looks both ways before crossing the road. This is because they believe in the objective reality of oncoming traffic."
] | [
"There are no experiments right now that suggest otherwise. Measurable results appear to be independent of the observer's consciousness."
] |
[
"Why is processed sugar bad for you if your body breaks down food into sugars cells use to power your body?"
] | [
false
] | null | [
"There are two general reasons why: refined (i.e. purified) sugar does not have other nutrients that come in healthy food, and it means that you're consuming a lot of sugar in a short time.",
"The first part is I guess pretty easy to understand. Refined sugar is empty calories - it replaces other important nutrie... | [
"Processed sugars get absorbed quickly in the small intestines and are sent to the liver to be transformed in fat. The amount of energy is so high that the body does't use it immediately, so it stores it instead of eliminating it. ",
"To do so, the pancreas releases a large amount of insulin to process all that s... | [
"Sorry? Can you provide some evidence for this please"
] |
[
"At what age* do human babies start having their own bacteria in their stomachs? (*while in the mother's womb itself or after birth)"
] | [
false
] | The good bacteria that help digest stuff that is.. | [
"Initial colonization occurs at birth; prior to birth, they are sterile. In the first few weeks and months the intestinal ecosystem gradually shifts from what was acquired from the mother at birth to one that is more adapted to digestion."
] | [
"They aren't. They are transferred from mother's vagina (in case of vaginal delivery) and skin (through post-delivery skin contact), and then later also from everything that the baby sticks inside their mouth. ",
"The bacteria that live in your intestine aren't special intestine-only bacteria. They live in all so... | [
"Like the answer you got, they are sterile before birth and then acquire their bacteria at and after birth. And this can actually become a problem with C-sections because we are finding that, believe it or not, bacteria from the mother's vagina actually ends up being important for the baby to encounter upon birth. ... |
[
"If oral steroids such as prednisone and dexamethasone are immunosuppressants, why are they effective in treating Covid? I would presume you want your immune system in tip top shape, no?"
] | [
false
] | null | [
"From the ",
"NIH",
": “Patients with severe COVID-19 can develop a systemic inflammatory response that can lead to lung injury and multisystem organ dysfunction. It has been proposed that the potent anti-inflammatory effects of corticosteroids might prevent or mitigate these deleterious effects.”",
"For more... | [
"One thing I haven’t seen mentioned here in the replies yet is that Covid has different phases, and you give different treatments during different phases. ",
"Here’s a tweet by infection disease expert Daniel Griffin that shows the basics of these stages and what treatment you’d use during them. ",
"https://twi... | [
"This was probably already mentioned, but the immunosuppressive effect of glucocorticoids is dose dependent. Typically doses of 20mg/day for 3 weeks or longer is considered “high dose” and would start having impacts. ",
"Short course bursts really hit inflammation with very very little immune system change."
] |
[
"What exactly is a \"field\"?"
] | [
false
] | So, while reading about quantum physics, in all of its confusing mumbo-jumbo, I have come across the term 'field' often, like the electron 'field', or the higgs 'field', and various particles are simply excitations of these 'fields'. What exactly does this mean? What are these fields? Is it related to the theory that says that the universe exists in eleven(?) dimensions. The way I visualize it, it is similar to sticking your finger into a two dimensional world/plane. All that would appear in the world would be a small circle made out of a cross-section of my finger. In my mind, the small circle that my finger makes would represent an excitation in the 'field', and the 'field' would be either my finger or the entire 'third dimension'. Though this visualization seems like it would only work in accordance with the 'eleven dimension' theory. So what exactly are these fields? Is my visualization accurate? If not, what might be a better one? thanks in advance | [
"It's simpler than all that. A field is something that has a value at every point in space. For example, if you consider the surface of a body of water, at each point the water has some temperature, so you could call the temperature field the temperature at each point on the water."
] | [
"Well you can consider things like an electric field or a magnetic field or a gravitational field, they can extend indefinitely. Instead of considering the electric field of a single object, you can consider the magnitude of ",
" electric field throughout the entire universe.",
"Quantum fields are a bit more co... | [
"A field is a function of space and time, as would be written f(t,x,y,z,) typically, that has a defined value for each point; that value might be zero however.",
"We could define the wind direction and speed as a vector field on the earth. Temperature distribution and elevation serve as good examples of scalar fi... |
[
"What are the ways to measure very high level of radiation?"
] | [
false
] | What are the ways that very high levels (Chernobyl, 20,000+ ) are measured? Is it a matter of Geiger counter being able to sample at a very high frequency or there is some other type of sensors that are being used for those kind of levels? Edit: I realize how Geiger counters work, so I was wondering if it is simply an issue of electronics to register that high of CPM count. Well that and some insane shielding to be able to work in that kind of field. | [
"In some cases, detector size is reduced to ensure fewer overall photon interactions occur in the detector volume. This can also reduce the clearance time for space charge effects, allowing another interaction to be detected. ",
"In other cases, alternative detector types are used (semiconductors) which can be ma... | [
"Perfect! Thank you for the reply. Tried to google this for a while to no avail."
] | [
"You can also increase distance since the radiation generally drop with the square of the distance (for small sources).",
"Could of course be confusing if there are many sources around as in the chernobyl case."
] |
[
"What effect does the lack of gravity in space have on astronauts' digestive systems?"
] | [
false
] | null | [
"Gravity doesn't really play much of a role in our digestive system. There are a series of muscles that line every part of our digestive track (from throat to anus) that push the food towards the next stage in the system. You could technically eat, swallow, and digest all your food while hanging upside down.",
"e... | [
" How does digestion change while astronauts are in space?"
] | [
"What about balance? I used to have nightmares as a kid (I used to get dizzy, and I HATED IT) that I'd be in space and just be stuck in extreme dizziness. My head spins just thinking about it..."
] |
[
"Is eating a venomous creature as deadly as being bit by a venomous creature?"
] | [
false
] | It would still have venom sacs filled with the toxin right? Would your digestive system care or just take it like a boss? | [
"It's important to note that venom != poison. Venom is dangerous intravenously, and poison is generally absorbed through through tissues. For instance, you are safe to drink most animals' venom, excepting those animals which don't produce their own venom, but rather \"steal\" a poisonous toxin from another creature... | [
"Not that simple. You can drink rattle snake venom. It's chemically similar to egg whites. By that same token, injecting yourself with egg whites is a bad idea.",
"I don't know what other venoms are nontoxic when ingested, but I'm sure there are others. ",
"Also you would have to deliberately leave the venom gl... | [
"Absolutely not the same thing. A protien based venom can be digested by your digestive system. Most snake venom, for example, contains a mix of peptide and related toxins, and also neurotoxins. I'm not sure if the neurotoxins would still take effect."
] |
[
"How are drugs such as cancer drugs delivered to specific cells within the body?"
] | [
false
] | How are drugs or biological cargo delivered artificially throughout the body? How do they target specific cells rather then all cells? | [
"This is one of the biggest challenges in drug research. Most drugs ",
" have targeted delivery - the drug is distributed evenly throughout the body (with certain limitations, such as the blood brain barrier preventing certain compounds from crossing) - but they target specific ",
", so that they can only act w... | [
"but they target specific receptors, so that they can only act where those receptors are present. ",
"This. One of the current strategies drug companies are investigating is the development of an effective antibody-drug conjugate. ",
"Antibodies are immunoglobulin that are an innate part of the immune system.... | [
"Actually antibodies are part of the adaptive immune system because they are produced in response to an antigen. I'm not familiar with this technology but how will the drug (which I assume is conjugated to the FC portion of the antibody) actually detach and cross the membrane of the target cell?"
] |
[
"Why certain chemicals are cancerogenic?"
] | [
false
] | What is the chemical mechanism of cancerogenesis caused by cancerogenic chemicals and why many of aromatic compounds fall in this class? | [
"There is no single mechanism of oncogenesis. Cancer is simply cumulative DNA damage, and anything that causes DNA damage can (with enough time) cause cancer. There are many mechanisms that are involved in DNA replication and repair, and so there are also many possible mechanisms that lead to DNA damage.",
"That ... | [
"Carcinogenic is the term you're looking for. And aromatic compounds are carcinogenic because they have a higher likelihood of mutations because that aromatic ring looks similar to some dna molecules. They get incorporated into the dna. Low amounts of mutation can be taken care of by natural mechanisms but the prop... | [
"Not exactly accurate, although I think it's mostly mis-phrasing; they don't get incorporated into the DNA per se and most aromatic compounds are not really that similar to nucleotides either.",
"The aromatic compounds, due to their electron makeup that makes them aromatic (delocalized electrons) are largely flat... |
[
"Does light exert a gravitational pull?"
] | [
false
] | I know light can be affected by gravity (ie curve around black holes and such) but could sufficiently large amounts of light energy exert a gravitational force on things? E=mc 2 and all that? | [
"Yes; you might find the idea of the ",
"kugelblitz",
" intriguing. Generally there will be a gravitational attraction between any two things for which the system as a whole possesses ",
"invariant mass",
", and note that Newton's 3rd law (1) implies that if a massive object exerts a force on light, the lig... | [
"\"",
"Wheeler's Geon",
"\" is a proposed particle composed of nothing but light, with high enough energy density to bend its own light into a loop."
] | [
"From a Newtonian standpoint, there is no universal speed limit and no reason light must travel at C. But even if you assume light always travels at C, that doesn't prevent gravity from bending the direction of light at eg 9.8 m/s",
" (though in GR it is twice the Newtonian value)... "
] |
[
"Possibly stupid question but how do we know some ancient civilisations believed in the afterlife vs writing about it for entertainment like we have for books/movies?"
] | [
false
] | null | [
"Because we often have records indicating they did.",
"You can find records or accounts of punishiments being carried out against non-believers in most ancient societies.",
"Not to mention people didn't create complex rituals off of fictional characters until Star Trek conventions were a thing."
] | [
"didn't create complex rituals off of fictional characters until Star Trek conventions were a thing.",
"Lord of the Rings?"
] | [
"I'm talking about something resembling religious services. There are many fictional stores in history that weren't treated as truth. The Journey to the West for example."
] |
[
"How did we prove that elementary particles are indivisible and how indisputable is that proof?"
] | [
false
] | null | [
"First thing to understand is, that there can be no such proof. Apart from the impossibility of having indisputable proofs in science in general, we can only have more or less usefull transient models, whose limits of applicability are just yet to be found.",
"What we can find out is whether there are additional ... | [
"It’s also important to note, in addition to this excellent response that in quantum physics, shorter wavelengths means more energy and thus there comes a point where the technology we use to interact with the particles is too strong not to alter the particle in fundamental ways. Furthermore we then get into the en... | [
"Yes, but as ",
"u/Badger_Wadger_420",
" pointed out, the Heisenberg uncertainity makes the whole picture much more complicated. In high energy regimes you have production of particles from the vacuum that make it hard to have a \"clean\" view of what is going on, the LHC needs to filter out a lot of irrelevant... |
[
"why is it that an impact to the testes results in a delayed pain?"
] | [
false
] | null | [
"I would suggest that the interpretation of the experience as painful is a mental process and takes time. If the experience is a major trauma, shock can delay the onset of pain for a good deal more than a few seconds.",
"Or, because all your brain power is in denail - 'OH SHIT THAT DID NOT JUST HAPPEN!', before i... | [
"I've had that happen but with my finger. It got shut in a door and the door locked. I started to walk away but I was caught on something and only then I realized what the hell just happened."
] | [
"Probably has to do with the fact a lot of the nerves involved in a man's junk actually lie within the upper abdomen. Like a shark's testes are somewhat located near the middle lower part of its ribcage. For some reason evolution decided to move our junk down and outside of our body so the nerves are still in our... |
[
"How sanitary are public pools, really?"
] | [
false
] | Is chlorine effective enough to keep them clean? | [
"Depends on your definition of clean. Is there piss in there ? Yes. Peoples skin ? Yes. Would you get sick drinking the water ? Most likely not but it's not recommended."
] | [
"pH is 0",
"I sure hope not."
] | [
"Chlorine in pools is not effective at eliminating ",
" species. These little Apicomplexan protozoans cause diarrhea, among other unpleasant symptoms, and can be lethal in immunocompromised individuals. A lot of attention was drawn to Cryptosporidiosis (infection with ",
" species) when the AIDS pandemic broke ... |
[
"Gambler's fallacy"
] | [
false
] | [deleted] | [
"Coin flips are independent events. A run of heads will not change the probability of subsequent flips.",
"The somewhat-intuitive ",
" line of reasoning goes something like this: \"I just got 10 heads in a row. The probability of 11 heads in a row is astronomically small, so the next coin toss is more likely... | [
"Don't know why you're getting downvoted.",
"AnteChronos's comment is completely accurate, if you don't account for any of the variables that do exist, however minute they are.",
"There are so many variables that actually affect the outcome of a coin toss. The odds are never ",
" 50/50."
] | [
"You're correct. The probabilities are independent for each new trial. ",
"Here's an analogy that might help.",
"You're going to flip a coin four times. There are 16 possible outcomes, each with equal probabilities. If you wrote each possible outcome on a piece of paper, you'd only have one piece of paper that ... |
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