title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Is every black hole surrounded by a spinning disk of matter and heat?"
] | [
false
] | Im wondering if humanity could ever come close to a black hole, or if we would get killed by the radiation, heat etc.? | [
"Nope, their are black holes with no disk but they are nearly impossible to find them since the disk is the reason we can see them, their are also theoretical atom sized dark holes all over the universe. As for your other question, it depends on the size of the dark hole and the amount of mater around it. If the pl... | [
"Theoretical dark holes atom sized. I've never heard anything about that, do you have a source explaining what you mean?"
] | [
"/u/ODISY",
" may be referring to WIMPs (",
"Weakly Interacting Massive Particles",
"). One possible ultimate end to black holes. Although they would be much much smaller than an atom. "
] |
[
"If North Korea got a missile with nuclear material into the shallow water near one of it's targets (Hawaii, Japan, Guam) would this still be dangerous for the people nearby? What about the marine life and food chain?"
] | [
false
] | So the test fires from North Korean missiles have proven to be inaccurate, but lets say that there was a lucky shot and a missile hit the shallows near one of the above territories and it contained nuclear material. Would it have to detonate to have any noticeable effect. What would be the best course of action to clean it up if it were to happen. | [
"Would it have to detonate to have any noticeable effect.",
"Hard to say with certainty, because people who have that kind of knowledge of NK's missile program are probably forbidden from sharing their knowledge publicly. One of ours (USA) would almost certainly have to detonate (barring a manufacturing flaw whic... | [
"Do some reading on Operation Crossroads for a more detailed answer. The short answer is that the Bikini Atoll tests involved two detonations.",
"The first was an air burst, in which a bomb exploded fairly high above the testing area. You don't get a whole lot of radioactive ",
" off of an airburst, but as to t... | [
"I went and looked up the Bikini Atoll tests,",
"http://www.youtube.com/watch?v=-l6Q8Q1smwg",
"The wall of radioactive spray that was produced, how far would the radioactive steam and spray spread, would it be carried further than if it had detonated over the surface of the water?"
] |
[
"Nephew asked this question and I didn't know how to answer succinctly (he's 7yrs old) - \"If hot air rises, why doesn't hot water rise too?\" He means in a body of water, why doesn't the hot water sit on the top of the bath, and the cold at the bottom?"
] | [
false
] | null | [
"You should explain that things don't rise because they rise, they rise because they are less dense. That's why air rises through water, and why soap sinks to the bottom of the bathtub.",
"Then you can explain that a hot water balloon would rise in a pool as well because it is less dense than cold water. ",
"Yo... | [
"Or sprinkle something light, but which sinks, into water (probably wet ground black pepper would do) and put it on low heat on a stove. You'll see the particles moving as the water circulates."
] | [
"Normally when things heat up they expand and become less dense, causing them to rise above the more dense liquid/gas. This is called thermal expansion. Some substances undergo negative thermal expansion where they actually expand when cooled. Water does this between approximately 0 and 4 degrees celcius."
] |
[
"What causes the variability in malleability between metals?"
] | [
false
] | For instance, copper and gold are much more malleable than, say, iron. All three are cubic, though iron is body-centered versus face-centered. Is that what causes the difference or is there something else? Why is gold even more malleable than copper - does it have something to do with increased density? | [
"Malleability is mainly influenced by the energy required for planes of metal atoms to slip past each other. As you said, copper and gold assume a face-centered cubic structure. In this structure, the atoms are packed in such a way that there are four sets of close packed layers that can easily slip past each other... | [
"Copper and gold are FCC, not BCC."
] | [
"You're right, thank you. I changed the mistake. Wasn't paying enough attention when writing my answer."
] |
[
"What makes some medical conditions (such as cancer) genetically transferable while some conditions that would seem to be genetic, totally random?"
] | [
false
] | null | [
"I'm not sure I understand your question. Some diseases are genetic, some have a genetic component but interact with the environment, some come from the environment and have no genetic component. "
] | [
"Well, I tried to give some context but you said not to. Then you said the question was ok, but not the extra text. ",
"rom albasri[M] via ",
"/r/askscience",
" sent 23 hours ago",
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"We do not o... | [
"Sorry I missed this message. I don't recall your original post. What are you trying to ask exactly? Maybe we can work on a good phrasing together"
] |
[
"Is p53 mutated in every Triple Negative Breast Cancer Tumor?"
] | [
false
] | If not, how is TNBC treated in this case? | [
"p53 inactivation does not, as far as I know, have much of a bearing on treatment. I think p53 inactivation confers a poorer prognosis in general, but then again most cancers inactivate p53 at some point.",
"The current treatment for breast cancer is targeted at the receptors the specific cancer uses to grow, but... | [
"The p53 gene remains normal in many triple-negative breast cancers. Although the loss of p53 is a strong factor in the development of cancer, it is not required for the development of a malignant tumor. Although this is oversimplifying a complex topic, you can imagine that p53 by itself is not strong enough to pr... | [
"Thanks, so basically general, wide use treatments would be used to treat TNBC? I found a paper on a small molecule called DPCPX which inhibited A1 receptors found in TNBC tumor cells, which would result in an increased rate of apoptosis. I was just wondering if p53 was ever capable of being functional in TNBC tumo... |
[
"What is physically happening in an electric generator when the torque of the rotor is increased?"
] | [
false
] | Speaking of a synchronous generator with a constant RPM rotor. As far as I know, the increase in torque translates to an increase in current in the coils. What is physically happening? Put another way: How is mechanical energy physically translated to electrical energy? | [
"As far as I know, the increase in torque translates to an increase in current in the coils.",
"It's more meaningful to think of it the other way around -- to say that an increase in coil current requires an increase in torque to maintain the same rotation speed. A generator operating at a constant RPM must incre... | [
"For a given electron current flow in a coil of wire, the surrounding magnetic field is proportional to the current. ",
"Diagram"
] | [
"You're pretty much right. Increased current in the generator stator coils due to increased load leads to a stronger magnetic field in the bore. A stronger field means a stronger force opposing the rotation of the rotor, so more torque is required to balance out this force or the rotor will slow. "
] |
[
"How do materials both refract and reflect light simultaneously?"
] | [
false
] | [deleted] | [
"When an EM wave hits a boundary between two media, the transmitted wave has a different speed and wavelength than the incident wave. However, Maxwell's equations, which describe EM wave behavior) require that the fields be continuous at the boundary. Not surprisingly, these requirements are called \"boundary con... | [
"In terms of light photons rather than wave theory, each individual photon can either refract (go through the boundary) or reflect (bounce off it). It is purely a probabilistic process."
] | [
"That's true, but the boundary conditions in the photon problem are the same. It's just the meaning of the wave that differs."
] |
[
"Why are specific heat capacities of unknown substances important? What are uses of low/high specific heat capacities?"
] | [
false
] | I admit this is for homework, but because I don't want to act like I came here without doing any work I will tell you what I know about specific heat capacities. A specific heat capacity is the amount of energy required for an object to go up(or down? Someone confirm this please?) by 1 K or C. So if it's lower it heats up faster than a higher one(assuming the rate of energy input is the same). That's all the relevant stuff that I can think of. I haven't learned too much about energy yet so I'm at a loss as to how to answer the questions. If anyone could please help that would be great. | [
"The oceans are a ",
"major heat sink",
" for the planet, due to the high specific heat of water."
] | [
"Say you put a dish in the oven and let it cook for a while. You take it out and let it cool for a bit. When can you handle the dish with your hands?",
"If the dish is made of a high heat capacity material like glass, it is storing a lot of energy. As it cools it gives off this energy as heat. It will take a ... | [
"Space ships create a lot of heat from friction with the atmosphere",
"This isn't quite correct. Most of the heat comes from the (incredibly) rapid compression of the air below the spacecraft, not friction. These are not the same thing.",
"[I wish I had a better citation for this, but ",
"here it is",
"."... |
[
"why you DON'T develop resistance to some medications?"
] | [
false
] | I know people who take drugs for HTN for years or Anti-depressants and etc. so why don't you develop resistance to them? or why do some side effects go away but the main effect of the drugs persists without increasing the dose? (i think side effects are because of the same receptors but in a different part of the body. (also I know all the drugs don't work by blocking a receptor)) | [
"Often, the meds are either interacting directly with the body systems as a substitute for missing/tiny titers of the natural active component, or act as an antagonist for the same, so metering/shutting down the target system. This isn't quite the same as other systems that can develop tolerances (thereby requiri... | [
"I’m a doctor. Medications act on enzymes or receptors. These medications can activate receptors, de-activate them or turn on/off chemical pathways. ",
"The question becomes which pathways, when activated/inactivated cause I disruption of homeostasis (the bodies ability to regulate itself). If a drug turns on/off... | [
"We do know that SSRIs cause a withdrawal of sorts if stopped abruptly, this implies some sort of adaptation in the brain's serotonin system, or some other downstream effect. To really answer why you don't generally grow resistant to SSRIs would require to understand exactly why SSRIs work for depression, and we do... |
[
"What happens in our brains and chemistry when we control an emotion like reigning in fear?"
] | [
false
] | [deleted] | [
"In the absence of someone specialising in this area, the frontal lobes are responsible for most emotional responses, but the cerebral cortex (the 'thinking' part) can override this part of the brain where the emotional response is inappropriate. For example when you hold back tears to save face when something upse... | [
"I'd like to clarify a couple of things in here. ",
"First, the frontal lobes are part of the cerebral cortex. The cerebral cortex is the layer of folded brain tissue on the outer surface of the brain that is divided into frontal, parietal, occipital, and temporal lobes. ",
"There are many parts of the brain ... | [
"Many of the feelings we have such as fear and extreme happiness are due in part to the balance of neurotransmitters such as serotonin, dopamine, and adrenaline. This is also why many designer drugs give you that high, because they can mimic the natural compounds in your brain chemistry."
] |
[
"Can physicists capture a gluon particle on its own, or even collect a pure sample of gluons, and would it be massless?"
] | [
false
] | null | [
"Gluons and quarks are subject to the strong force. This makes them special because they can never appear by themselves. Their attraction to other strongly interacting particles is so large, that if you were to try and pull them apart to examine one by itself, the field lines connecting them would snap and create m... | [
"Their attraction to other strongly interacting particles is so large, that if you were to try and pull them apart to examine one by itself, the field lines connecting them would snap and create more particles which then serve to pair up the particles you were trying to pull apart. [Sort of a cartoon explanation ob... | [
"The closest thing to this is the currently-hypothetical ",
"glueball",
", which is a bound particle made only of gluons. It is expected to have a mass 3-5 times that of the electron. There is currently an American experiment called Glue-X which is developing the capability to produce and detect these (larger e... |
[
"Is all organic life involved in symbiosis of some sort?"
] | [
false
] | [deleted] | [
"Well, it could be argued that all eukaryotic life ",
" symbiotic, since according to endosymbiotic theory, organelles like mitochondria and chloroplasts are actually bacteria that figured out how to survive inside another cell."
] | [
"ok fine, bad example - use those bacteria individually as the example. pre-hookup. the point is if you follow back far enough, to the first life form, there were no other life forms to be in symbiosis with"
] | [
"How could you even tell what the \"first life\" is? Is a nucleotide alive? Probably not, it can't self-replicate. Is a strand of self-replicating RNA alive? Maybe by some definition, but the standard answer is no because it doesn't exhibit all the characteristics we associate with ",
"living organisms",
".... |
[
"Is it easier for an exhaust fan to pull air through a duct rather than pushing it into the duct?"
] | [
false
] | I'm planning on adding a new bathroom exhaust fan and somehow I'm thinking that it if it were mounted closer to the roof (in the attic) it would be able to pull the humid air out of the bathroom through the duct more efficiently. As opposed to being ceiling mounted, it would have a harder time pushing air through the duct. Is there any basis for this? | [
"This might be a better question for ",
"/r/AskEngineers",
" but I think in most cases it won't be different enough to matter. You are playing with three basic paramters: suction pressure, discharge pressure, and fan speed. Assuming fan speed is constant then you might just be playing with the first two. The... | [
"From a volume flow standpoint, the location of the fan does not matter. In a given section of duct or pipe the pressure difference between the inlet and outlet is proportional to how fast the fluid is moving. This pressure differential will be the same if the fan is at the inlet, outlet, middle, or if the duct sec... | [
"I would certainly think that reducing pressure in the duct by sucking would decrease resistance in the duct."
] |
[
"Why do we get hungry if we have excess calories already stored in our body."
] | [
false
] | If our body stores excess calories as fat cells, why do we get hungry again when our body could instead burn off some fat cells first which would also reduce health problems associated with carrying too many fat cells? | [
"The short answer is evolutionary history - it's only been in the last few thousand years (arguably the last thousand) that we've had an abundance of food. Before that, we were just like other foraging animals - we had to constantly be looking for food. Because of this, it would be entirely possible that we may ha... | [
"Apparently, an obese man once fasted without food (but consumed water and vitamins) for 1 year and two weeks. So, under the right conditions, your fat store could keep you going for quite some time.",
"Source: ",
"http://pmj.bmj.com/content/49/569/203.abstract"
] | [
"Hunger also has to do with low levels of sugar in the blood. When you have low blood sugar, your pancreas and stomach secrete glucagon and ghrelin. These hormones are responsible for the breakdown of stored energy and hunger stimulation. The response is an increase in circulating glucose in the blood, which raises... |
[
"Is the Columbia River Gorge a Fjord?"
] | [
false
] | The Gorge is on the border between Washington and Oregon, USA and is very similar in appearance to some fjords. | [
"The Columbia River Gorge is considered a canyon, but the way it was formed is basically the same as a Fjord. ",
"Several lakes attached to the gorge are referred to as \"fjord-like\" on ",
"Wikipedia",
"."
] | [
"Fjords are typically formed by glacial erosion. The Columbia River Gorge was actually formed by floodwaters, during glacial periods, in events known as the ",
"Missoula Floods.",
" ",
"The damming of river waters in Montana by glaciers formed massive lakes. Periodically, the ice dams collapsed, releasing hug... | [
"Wow! Amazing info, thank you so much."
] |
[
"Could wireless electricity enable us to build solar farms in space and then let us use the power back on earth?"
] | [
false
] | null | [
"Yes",
". Actual wireless power tends to degrade quickly but we could set up solar farms in space and use things like microwave transmitters to send the power to special receiving stations and have them sent out via more traditional power lines from there."
] | [
"People have proposed ways to transmit power from space to the ground, such as focused microwave beams. But any such scheme likely has some major concerns associated with it. For example, if you have a powerful microwave beam, how do you ensure that it is impossible for it to go \"off target\" and harm people/liv... | [
"Interestingly enough, the Japanese company ",
"Luna Ring",
" has proposed an ambitious plan to do exactly this."
] |
[
"10th Grade Chemistry Teacher needs help, actually, questions."
] | [
false
] | [deleted] | [
"This sat in the spam filter all night. I can release it, but since it is 9 hours old, no one will see it. You should repost it, and message the moderators if you don't see it in the \"new\" queue."
] | [
"Just a suggestion/thought (I'm a Spanish teacher, so my topic-specific usefulness to your question is limited, but...):",
"\"Is biodiesel a promising new energy source?\" is a closed-ended question. They will find sources that say \"yes\" and stop researching."
] | [
"15-16 year old kids are very interested in science that is bordering science fiction, but still somewhat scientific. I know I was - I went into materials science because I thought nanotechnology = nanobots + molecular manufacturing. Turns out it's not, but it's just as cool, you just need to know a little more mat... |
[
"Does Photon Redshift (and blueshift) violate conservation of Energy?"
] | [
false
] | So, according to the laws of physics, energy cannot be created or destroyed, meaning the amount of energy stays constant, however, Photon redshift has the photon losing energy, but wouldn’t that violate energy conservation? Because what exactly would the photon be losing energy to? If there’s nothing for the energy to be transfered to, the only way for the photon to lose energy would be to destroy energy, which according to the laws of physics, isn’t allowed, but since the photon is losing energy and it’s not being transfer, is energy being destroyed as the photon redshifts? | [
"This is a violation of the traditional way conservation of energy is explained, which is not really a problem with the conservation law, but a problem with the more simplified version we learn (which works for pretty much any reasonable situation we're in).",
"The easiest way I know to discuss this is by looking... | [
"If it's due to expansion of the universe: Yes.",
"If it's due to motion in a gravitational potential: No. The difference comes from the energy in the gravitational field.",
"If it's due to you changing your reference frame: No. Different reference frames can assign different energies to the same objects."
] | [
"what exactly would the photon be losing energy to?",
"The gravitational field.",
"Gravitational potential energy (and, to a lesser extent, kinetic energy as well) is a tricky business in arbitrary spacetimes (no distance parallelism, no covariant expression for gravitational energy density, potential lack of t... |
[
"Do microchips implanted in the body require energy to function? Do they absorb it from the bloodstream?"
] | [
false
] | [deleted] | [
"Yes they require energy, no they don’t absorb it through the blood stream. Blood supplies mostly oxygen to the different systems of the body but not directly energy. Oxygen is a key component in the chemical processes our body uses to break down storage molecules in order to create useful molecules that release en... | [
"They either require their own power or don't need power at all. An example of something that might not need power would be something like a Radio Frequency IDentification (RFID). The tiny bit of information it's carrying is read by providing energy to it via a reader and reading the response. So it is only \"power... | [
"To go deeper into this, an RFID chip is basically just a specifically designed mirror, reading an RFID chip with the reading device works not that different from how SONAR works.",
"The device emites a specific pulse of small, weak, EMR waves at the RFID chip, which has a small antenna inside of it. The chip rec... |
[
"How is Hawking Radiation possible if nothing \"escapes\" a black hole?"
] | [
false
] | null | [
"Hawking radiation originates from outside the horizon."
] | [
"Ok, thats good to know. I still dont get how it could exist. Unless i misunderstand its from the black hole emitting particles, correct?"
] | [
"It's a complicated effect. But to summarize it as briefly as possible, an observer far away from the black hole sees the spacetime just outside the horizon as having a small but nonzero temperature. And anything at nonzero temperature radiates thermally.",
"So particles are created just outside the horizon and r... |
[
"How did the first humans with 46 chromosomes breed?"
] | [
false
] | [deleted] | [
"I asked a ",
"very similar question",
" about a year ago, ",
"r/askscience",
" was very helpful. ",
"I'm not going to try and explain it all now as pretty much all the info is in the link, but in essence you just have to accept the epic scale of evolution. Though the probability of such an event seems mi... | [
"The TL;Dr of the link is basically that how the DNA is arranged in chromosomes doesn't matter so much, what matters is that the offspring gets a complete set of DNA from the parent. A merged or split chromosome makes it easier to get a complete set of DNA, but it is not required. So a person with a fused chromos... | [
"I would answer this on my own but PZ Myers has done such a great job I don't think I could improve on it. Here is the ",
"link",
" explaining how the change in chromosome number could happen and still allow interbreeding that could eventually lead to speciation."
] |
[
"How hard is it to create high speed rail systems?"
] | [
false
] | With creating loads and loads of highspeed rail systems very fast (2-3 years each) I was wondering how hard is it to make these things? They don't seem to have a problem with making them. Why can't we have these in the US and Canada or even spanning the EU from end to end? How much does a highspeed rail system cost /km compared to a normal one? | [
"Unfortunately I can't answer your question, but last night as I was falling asleep on a high speed train in China, I was wondering exactly the same thing. I would imagine that it's not the initial investment of capital that is the barrier here, it's simply that Americans are more attached to their own cars and the... | [
"In the UK at least the problem is investment and actually putting down the network. Purchasing land will be ridiculously expensive so existing track will have to be upgraded. Of course, no one wants such a large disruption to service so it isn't going to happen very fast. In china it's quite possible to bulldoze t... | [
"I've read that it's something like 20 million $/km to do it in North America."
] |
[
"If scientists eventually observed proton decay, how would this affect the Standard Model? Would evidence of proton decay force us to change any current theories?"
] | [
false
] | null | [
"The Standard Model does not allow for proton decay, so it would definitely force us to change the current theory. That said, we already have set a very high lower limit on the lifetime of the proton, and I don't know if there are any models being discussed currently that allow for proton decay but with a longer li... | [
"Quite a few so-called GUTs -- Grand Unified Theories -- predict proton decay. The Standard Model on the other hand does not allow it. ",
"If proton decay is observed we require to extend the Standard Model such that it includes the process. This has happened before with processes such as neutrino oscillations, e... | [
"I don't know if there are any models being discussed currently that allow for proton decay but with a longer lifetime than that.",
"Believe it or not, there are! :) Many ",
"grand unified theories",
" allow ",
"protons to decay",
" (by allowing violations of baryon number symmetry), and many of them pre... |
[
"Is there a point of no return associated with dehydration while still being alive?"
] | [
false
] | Can you be so dehydrated, while still being alive that no amount of liquid however administered will save the person from death? | [
"According to ",
"this",
", there is a point at which ",
" water will not save you from death, but apparently you can still survive if you are re-hydrated intravenously.",
"So, no. You are either dead, or can be re-hydrated intravenously. There doesn't seem to be an in-between. And even if there were, you'd... | [
"Any idea why you cannot be hydrated orally?"
] | [
"Yes, it's possible to be alive, very ill, but so dehydrated that it causes fatal kidney damage. There was a recent case where a women survived a car crash but was not found for 3 days (her boyfriend was killed in the crash). She died of kidney failure 3 days after she was found.",
"Ms Bell, who was a mother, had... |
[
"If Crude oil is made from decaying plant and animal matter, wouldn't the fact that the moon Titan has large crude oil deposits suggests that life at some point existed on this planet?"
] | [
false
] | [deleted] | [
"Titan doesn't have crude oil, at least not in the way you'd picture it. On Earth, much of our oil is resultant of the geological deposition of biomass in sea beds. This process produced a hydrocarbon mixture we call oil. However, there are many kinds of hydrocarbons, it's not a single molecule.",
"On Titan, you ... | [
"Excellent answer. I just wanted to add that there are also some chemical inorganic processes which produce methane ",
" sunlight as well. The serpentinization of olivine for instance (Olivine + water + carbonic acid → serpentine + magnetite + methane).",
"Such a process could act throughout large volumes of pl... | [
"No oxygen, so without an oxidant, you wouldn't get the burning world your heart desired. The hydrocarbons in Titan's environment might as well be as inert and boring as water."
] |
[
"Is there good reason that the many worlds interpretation of quantum mechanics is so popular?"
] | [
false
] | The underlying issue I’m having is that science is terrific at not giving anything value without evidence, but I hear about the many worlds interpretation of quantum mechanics all the time. So I’m wondering first, is there some conceivable method of testing this someday that I’m not aware of? I get that it’s only an interpretation, and could explain what we see in a way, but I worry that this interpretation is just a lot of fun and that’s what’s making it popular. Second, let’s assume we could devise some experiment, and it turned out that everything that could happen indeed does, what could we do with this knowledge? Or maybe that’s not even possible to speculate about. | [
"MWI is popular for a few reasons.",
"It is the most direct and simple reading of quantum theory. Many worlds are just the inevitable consequence of the basic equations of quantum mechanics. All other interpretations should then be understood as efforts to get rid of all but one world. So, unless MWI is unwork... | [
"CI is probably still the most popular in general because of how it taken for granted in many textbooks and courses, but it is relatively less popular among folks who have done a deeper dive into philosophy/foundations of QM."
] | [
"Would you say that MWI is the most popular interpretation of quantum mechanics these days? If so, when did it become the predominant interpretation? My understanding (mostly from reading Wikipedia) is that the Copenhagan interpretation was originally the predominant interpretation, but I don't know when that chang... |
[
"Are lighter eyes more sensitive to light?"
] | [
false
] | null | [
"You're approximately right, but get a few details wrong:",
"Different shades of blue, and in irises with a limited amount of melanin, different shades of grey, green and hazel, are deter- mined by the thickness and density of the iris itself and the extent of accumulation of white collagen fibres, as well as pat... | [
"You're approximately right, but get a few details wrong:",
"Different shades of blue, and in irises with a limited amount of melanin, different shades of grey, green and hazel, are deter- mined by the thickness and density of the iris itself and the extent of accumulation of white collagen fibres, as well as pat... | [
"Waaay too many anecdotal and unsourced things being said here. Let's clear things up:",
"It isn't that you're more ",
" per se. It's more complicated than that. The experimental evidence for what I'm going to exlplain is largely from this paper: Graefes Arch Clin Exp Ophthalmol. 2013 Jan;251(1):195-202. doi: 1... |
[
"Possibility of large deepsea monsters"
] | [
false
] | I remember reading that we have explored less then 10% of the sea and it gives me chills to think about what may lurk in the icy depths of the sea, especially concerning giant monsters like the colossal squid. However, due to the very high pressure in these depths would it be possible for such things to exist or would all the creatures down there be minuscule in size? | [
"While the first live giant and colossal squids were only sighted in recent years, we've known about their existence for a long time. They're beaks have been found throughout the ocean, inside whale stomachs, and their carcasses have been hauled out of the sea and found on the shorelines.",
"However, we also know... | [
"I've read that there have been squid beaks discovered in the stomachs of sperm whales that are much bigger than those found on actual giant and colossal squids."
] | [
"Source:",
"\"The beak is considerably smaller than some found in the stomachs of sperm whales, suggesting there are Colossal Squid much larger than this one.\"",
"\n",
"http://en.wikipedia.org/wiki/Colossal_Squid#Defrosting_and_dissection.2C_April-May_2008"
] |
[
"P-47 Thunderbolt Propellor Damage. What would this do in flight, if anything?"
] | [
false
] | Hey , I saw this picture on another sub and was curious what effect this would have in flight, if anything at all. Also let's say, hypothetically, that if he could eject the damaged propellor blade, what effect would that have in flight also? Thanks! Here's the Picture: | [
"Purposefully jettisoning a prop blade in flight will lead to an uncommanded jettisoning of the rest of the prop blades, followed by a catastrophic and likely explosive failure of the rest of the engine due to a massive prop balance failure.",
"The blades will also take out whatever is in their path; control cabl... | [
"The P-47 was one of the largest 4-stroke single engine planes ever. They couldn't feather that engine during flight and land with another. They likely flew back with it at minimal power. ",
"Damage of that sort will cause less pull from that blade. That's not the problem. The offcenter distribution of rotational... | [
"Friend of mine actually lost a propeller blade in flight on his Bonanza at 6000. The other two blades flew off immediately due to the inbalance. Because there was no drag of air on the blades (it was a lot like throwing your car in neutral while holding your foot to the floor), the engine went past redline faster ... |
[
"What are the current and historical uses for desert sand?"
] | [
false
] | All I can find is glass. I imagine it was used historically for bricks as well, though Beach sand is better for construction and other products. I can only find article after article talking about how it "could" be used for concrete after this or that new production technique, but I'm not invested in potential uses, I'm interested in current and historical. There's a ton of it, and we've been around it for thousands of years. I have to believe there are some other good uses for it | [
"That much I know. But any google searches are populated immediately by dozens of pages talking about some new 'miracle procedure' that will make desert sand good for concrete. I don't believe it, i don't think it's going to happen. But I am curious if there have been historical uses for it."
] | [
"Desert sand is the product of aeolian erosion, meaning it is created by the wind moving and colliding sand particles. \nThis sand has small, homogeneously sized particles, that are well rounded. All of these things are bad for concrete, where you want sand particles with structures that \"lock in\" to each other t... | [
"The ",
"Wikipedia article on sand",
" lists several dozen different uses, including current and historical ones. Some of them would have similar issues as with concrete, but many others, for example filling sandbags, would not. Most of the applications have links to articles that discuss those applications i... |
[
"What type of clouds are these (picture link inside) and why do they form this way?"
] | [
false
] | We just had a small storm pass over us here in Dayton, Ohio and I've never seen anything like it. I've seen the "egg carton" type clouds, but these I can't describe vaguely enough to search using Google. Anyone care to explain? | [
"It's a ",
"\"new\" cloud type (i.e. one recently categorized, although informally)",
"But the cloud fan has proposed a \"formal,\" Latin name: Undulatus asperatus--roughly, \"a very turbulent, violent, chaotic form of undulation"
] | [
"They haven't in 60 years. :)"
] | [
"I didn't know they were adding cloud classifications. Elementary school science be damned"
] |
[
"If there are exactly 2 animals left of a species and they are to repopulate, how do successive generations not turn up with all sort of genetic diseases from inbreeding?"
] | [
false
] | I would guess that some gross shit gotta go down like father/dtr, mother/son, bro/sis, 1st cousin etc for the population to rise. How the hell you not get a bunch of TIMMAYS out of this? | [
"Genetic diseases from inbreeding aren't a guarantee, they're just slightly more likely. Inbreeding reduces genetic variation and also brings to light more recessive genetic traits, some of them harmful. Successive generations will be harmed by this but if they can survive long enough to generate a large enough pop... | [
"I doubt he's going to get the kind of answer he's looking for (with an emphasis on evolution/genetics) from another subreddit.",
"I know many scientists see religion and science to be incompatible, but many others would argue that they can coexist. Without getting into a debate on religion, OP's question seems t... | [
"I don't think you'll ever find any examples of an entire lineage arising from just two animals, much to noah's dismay, but such a thing could feasibly be possible if the two animals have no detrimental genetic traits. ",
"The only problem, aside from societal stigma, with inbreeding is that it magnifies recessi... |
[
"Can a large enough static charge move an object?"
] | [
false
] | [deleted] | [
"Can a large enough static charge move an object?",
"Yes; this is how the ",
"mass-to-charge ratio",
" of the electron was determined in the famous ",
"Millikan oil drop experiment",
". If you want to try this for yourself, try putting small paper shreds on a table, then take a balloon and rub it against ... | [
"Can a big static charge move an object? Yes definitely! It happens all the time, and you can test it ",
"yourself pretty easily",
". But can it move your smart watch? Probably not.",
"Electrostatic forces \"scale\" proportional to the surface area of the object. That means that if you have two similar objec... | [
"U.S. Patent 633,829 from 1899 describes a static electric machine. Not only does it exist, it has been around for a long time.",
"The rule of thumb is that for a air gap of greater than 1 mm, electromagnetic motors are more effective. For sizes less than 1 mm, electrostatic motors are more effective. Electrostat... |
[
"How is it possible that wifi routers have such bad signals"
] | [
false
] | A serious question, why is it that, even though a good connection to satellites across miles and miles of space can be established, if I moved my laptop about a couple walls closer in my house to my internet router I'd get much better signal? | [
"Another aspect of this is that consumer-grade wifi equipment is built to be just \"good enough\" while staying within very strict and severe cost constraints, while satellite systems make reliability of signal transmission a very high priority, with consequent added cost. "
] | [
"Different power ratings and frequencies. Longer wavelengths travel further at lower power outputs."
] | [
"The use of parabolic antennas for satellite transmissions means you can get away with weaker signals, as well."
] |
[
"What property of food determines the length in which something can safely be left out of the food temperature safety zone?"
] | [
false
] | null | [
"I believe it's the type of bacteria that are normally found in it at low numbers, and their speed of replication when temperatures are right. Some bacteria produce nasty stuff and if you let them live in meat for a while they can produce enough toxins to be a problem even after cooking. ",
"Different foods hos... | [
"A wet, neutral pH, and sugary environment is best for growing bacteria, so foods like melons are a bigger risk than dried crackers or a glass of pure water. These are generalizations, but useful ones. Bacteria like E. coli and salmonella prefer uncooked meat, and diseases like norovirus and staph can be transferre... | [
"Water activity is one important factor:",
"https://en.wikipedia.org/wiki/Water_activity",
"Substances like honey, dried fruit or grains, and cured meat have lower water activity than something like fresh meat or fresh fruit which can spoil more easily.",
"At least that is my laymen's understanding. "
] |
[
"Is there a reserve of animal DNA in case of exctinction?"
] | [
false
] | I know there are reserves for diseases and plant seeds in case we need to repopulate certain species. Is there something similar for the DNA of endangered animals in case we need to clone an animal to revive it from extinction? | [
"I have made a conscious decision to never doubt King George can do something.",
"I would also add that we save seeds from all the plants we can get our hands on. This has a very practical benefit for modern breeding a genetic manipulation as some plants possess traits (like disease resistance) that are very usef... | [
"I have made a conscious decision to never doubt King George can do something.",
"I would also add that we save seeds from all the plants we can get our hands on. This has a very practical benefit for modern breeding a genetic manipulation as some plants possess traits (like disease resistance) that are very usef... | [
"Thank you for the detailed response! Thats fascinating that theyre attempting to revive a woolly mammoth. I wonder if it will be a wierd hybrid of the asian elephant and mammoth like a mule or liger."
] |
[
"Are there any limits to time dilation?"
] | [
false
] | Let's say that there was a spacecraft that had practically unlimited amounts of delta-v, high thrust, decades of supplies, radiation shielding, and protection against any particles that it might hit. Its crew decides to go out and keep burning until they're going as close to light speed as possible. Assuming that they never have to worry about fuel or anything else, then how extreme could the time dilation end up getting? Could it even get to the point where they're able to experience the heat death of the universe within their lifetimes? Or is there something that limits time dilation to a certain rate? | [
"There is no limit. As your velocity approaches c, gamma (the time dilation factor) approaches infinity.",
"E: ",
"Like so"
] | [
"So if one were to answer OP's question as basically, \"given enough energy and speed, time dilation could get so large that the heat death of the Universe would happen in a few minutes of flight in this spacecraft\", then one would not be incorrect?"
] | [
"Well yeah, I know that you can never actually get to c, but I'm talking about just getting close enough to experience significant amounts of time dilation."
] |
[
"What happens to the last remaining atom in a lump of radioactive material?At which point does it disintegrate?"
] | [
false
] | (from an article in the Journal of Heuristics) | [
"Half life is just a a way to represent the probability of an atom to decay. No matter how many or how few atoms you have in a system, each atom has a 50% chance of decaying in one half life. These events are all independent, so one atom doesn't change based on the other atoms in the system. However, since there... | [
"The atom will decay with the same probability distribution in timing as the others, starting now...",
"Longer version:\nRadioactive decay is (to close approximation) a Poisson process. What that means is that each atom has the same chance to decay in a given period. The half life of an element is the length of t... | [
"thanks for your reply .",
"However the author also speculated on the (admittedly far-out) possibility long -lived particles-electrons ,protons....- are in this state simply as the remnant-particles from the big bang ,and thus may decay eventually.What's your take ?"
] |
[
"Angular Momentum Question"
] | [
false
] | I tried posting this to askreddit, needless to say I didn't know this subreddit existed. Anyways, my modern physics teacher again disappointed me in lecture with a poor explanation. I understand that the question is not really answered, but can someone explain how electrons have angular momentum without spinning on their axis? Orbital angular momentum is easy, but spin angular momentum makes no sense to me. | [
"I'm going to have to disagree with RobotRollCall here. We don't really know what spin is. It's ",
" intrinsic angular momentum. It 's an intrinsic property. It ",
" angular momentum, but it's not actually \"intrinsic angular momentum\". An electron does not spin on its own axis.",
"We know it's not angular m... | [
"The universe is under no obligation to make sense to anybody.",
"Spin is intrinsic angular momentum. It just is. The fact that we only encounter classical angular momentum in the context of something rotating doesn't matter. Spin is angular momentum in the absence of rotation."
] | [
"I think the best way of explaining this is with an analogy. Imagine the only type of energy you knew to exist was kinetic energy, i.e. you live in completely free universe where no potentials exist. This would all be fine, you'd have a law of conservation of energy, where the only type of energy is kinetic energy ... |
[
"BLACKHOLES: Is it possible there are blackhole cores made of different atomic structure?"
] | [
false
] | [deleted] | [
"I'm afraid I don't understand the question; there are no elements crucial to the formation of a black hole. All that matters is that you have an object of sufficient mass undergoing collapse. In a stellar collapse process, the star will fuse elements up to iron before undergoing its supernova phase, and then a who... | [
"No, because the properties of an atom are determined by its atomic structure, and the material that collapses into a black hole ",
" its atomic structure. During the collapse, all atomic identity is wiped out and you're left with an object that has no measurable properties other than mass, angular momentum, and ... | [
"Not really.",
"The gravitational interaction even at the neutron star level is sufficient that there is no ",
" structure to speak of (at least in the interior regions). All of the protons start binding to the free electrons or tossing off positrons, so you're left with just a bunch of neutrons. Since the elem... |
[
"What role does Insulin have in memory?"
] | [
false
] | this is in conjunction with an article im reading about the link between type 2 diabetes and alzheimers, it says there is a link but doesnt go any further as to say why. | [
"I can think of a few reasons that type 2 diabetes and Alzheimers may be linked, and none have to do with insulin directly...",
"Diabetes can cause damage to your blood vessels. Types of dementia may occur due to brain damage that is often caused by reduced or blocked blood flow to your brain. Many people with di... | [
"My first thought when I read this question about type 2 diabetes and alzheimers actually wasn't insulin but glucocorticoids (GC), which are hormones involved in glucose metabolism, but they also have many psychological effects. Exposure to high levels of GCs for example can lead to cognitive impairments especially... | [
"A little bit of a late response but I think this is an interesting question. Before talking about the link to Alzheimer's be aware insulin is actually an important signaling molecule/growth factor in the brain. In fact, the brain produces its own insulin (rodents even have a brain specific isoform) as well as bein... |
[
"What are the properties of the amplitude of a lightwave?"
] | [
false
] | I know that the frequency (length) of a lightwave is measurable spatially and that frequency affects our perception of the wave's color. Is the amplitude of a lightwave measurable spatially? Is amplitude a function of length? Does amplitude affect any perceptible properties of the lightwave (brightness/some other thing I don't know about)? | [
"The transverse components are ",
"an electric and a magnetic field",
". They do not have an intrinsic length-scale. The amplitude determines how much energy the wave transfers to something when it interacts, for example a higher power laser that can do more damage to your eye has a stronger electric and magnet... | [
"The amplitude of (the electric component of) a light wave is measured in V/m, which has no meaning in terms of a spatial amplitude. It's proportional to the amount of force a charge would experience when subjected to the field/wave.",
"The energy density of a field/wave is proportional to",
"E",
" + B",
"w... | [
"Thanks! That link is useful in explaining the separate components of a light (electromagnetic) wave."
] |
[
"Does heat from a candle in space move gradually and spherically away from it?"
] | [
false
] | So I saw this post about a candle in space which is round because there is no "up" in space. Does this mean that all the heat moves gradually and spherically? And what happens when the heat reaches a wall. Does it get reflected in some kind of way? Bonus question: If so, does it mean that a candle in space burns out faster because the heat is staying closer to the candle/wax itself? | [
"I believe what you meant is a candle in 0 gravity, since space has no air, thus no oxygen to fuel the fire. ",
"Good question, though. \"Heat\" (actually, it's hot air) moves upward in normal gravity since hot air is less dense than cold air. If you have no gravity, it will stay around the light. This is why the... | [
"Yes, the hot air would not change direction as it would if there were gravity. But the heat would still be transferred to the cooler air, much the same way as the sun heats earth."
] | [
"I am interpreting this issue as if you were on board a spacecraft, such as the ISS, in freefall, rather than if you were in a vacuum.",
"So if we ignore the oxygen issue for the candle then you have pretty much worked out how it would go.",
"Any radiative heat transfer will remain unchanged. Without gravity th... |
[
"Why do eyeglasses \"work\" even when held at arm's length?"
] | [
false
] | My understanding is that myopia makes images focus in front of the retina. Let's say that in my case it's 1cm. If I pulled my glasses forward 1cm, shouldn't it be the same as having uncorrected vision? Instead, I can see things clearly (even if a little distorted) if I look through eyeglasses even if I hold them a metre away from my eyes. How does that work? | [
"I'd venture a guess that you don't have a very strong prescription. I have a fairly strong one, and I can't move my glasses any more than 10 cm from my face without my vision becoming quite blurry.",
"Glasses correct myopia by diverging the light slightly before it enters the eye. This causes the image to focus ... | [
"The strongest prescription I ever had was about -3.0 diopters, so not particularly strong. Now it's -0.5 so even weaker. I guess this makes sense."
] | [
"The eye actually has a total power of about +60 diopters to focus the image on the retina. If your prescription is -3 then it means your eye has an extra +3 that needs to be neutralized to get the image to focus properly. As you pull the lenses away from your eye, it's still bending light coming through that lens,... |
[
"What does p-value really mean?"
] | [
false
] | null | [
"The easiest way I know to explain p-value is by thinking of an experiment like this: I have a coin and I want to know if it's a fair coin or not (aka- if when I flip it, it is actually a 50/50 chance of coming up heads vs tails). So, let's say I flip a coin 6 times, and I get all 6 of them heads. That would indica... | [
"Yeah, that is kind of the classic example, and captures it probably more succinctly than I did."
] | [
"would this be considered p-hacking?"
] |
[
"Does the speed at which you pass through a metal detector effect its sensitivity?"
] | [
false
] | *affect Say I have a 20g iron nail in my pocket, and this is right around the threshold of a metal detector in a security line. Would it matter if I ran through the detector at top speed or walked through the detector slowly? In my mind there are two considerations. One, running through may give the detector a short enough signal that the software filters it out as an anomaly (here I'm talking about speeds attainable by humans, I'm not trying to say that the piece of metal is going so fast that it exceeds the sampling rate of the detector, just that there are software controls to exclude false positives but in this case they would be filtering out a true positive.) Second, going through faster actually will generate a larger signal (like a magnet passing through a coil more quickly generates a larger current), so it's the person who walks through very slowly that is not detected. I am asking these questions with little understanding of the engineering or physics behind metal detectors, and was hoping you all could provide some insight. | [
"If the magnetic field of the metal detector were constant, then moving slow enough would not set it off. However, most, if not all metal detectors use oscillating magnetic fields, which you can basically think of as a magnet moving back and forth. In this case, it doesn't matter how you moved.",
"Addendum: A met... | [
"The more impressive feat would be flying it through an airport metal detector with no one noticing. "
] | [
"about 2000mph. so no you cant."
] |
[
"How does something like Chantix NOT produce withdrawals/nicotine cravings if it binds to nicotine receptors?"
] | [
false
] | . This isn't medical advice, just a random thought. I've considered trying Chantix but I hear it's expensive and I'm a little scared of the side effects... can't be any worse than smoking though! Anyway, thanks in advance. I love being able to ask scientists questions, I can't think of anywhere else I would be able to. :) | [
"chantix is a ",
" agonist, which means it binds to the same receptors, but doesn't elicit as strong a response. the response is weak enough that it doesn't lead to a lot of dopamine release downstream, so it won't really have withdrawal effects."
] | [
"Chantix is a what's called a \"partial agonist\" so while it activates the nicotine receptors (dulls craving) it also blocks the nicotine you smoke from binding to the nicotine receptor (uncouples the pleasure you receive from smoking). This second pathway of uncoupling the pleasure you receive from smoking a ciga... | [
"Syntrik/waterinabottle explained it nicely. Im well aware that we dont give medical advice however, But I would like a very fast rant/warning.",
"<ENGAGE RANT>\n I want to warn you and anybody else considering using this drug of one thing which isnt fully documented in the usage guidlines yet. Im not going to ta... |
[
"Is it \"healthier\" to remove your wisdom teeth even if they are not bothering you?"
] | [
false
] | I was having pain with one of my wisdom teeth, and my dentist recommended that I remove them all. Are there any good reasons why I should/shouldn't? | [
"Caveat: I am not a dentist, but I am someone with a cool dentist who keeps me up to date on relevant research. ",
"Prophylactic removal has fallen out of favour in many places around the world. The UK are against it, with the NIH stating \"The practice of prophylactic removal of pathology-free impacted third mol... | [
"I'm a dentist. Short answer is that you don't have to have the other wisdom teeth removed unless they appear to have the potential to cause resorption, decay or gum disease with the second molar forward of the wisdom tooth. This is another muddy issue. Not all dentists see it the same way. For more detail read on ... | [
"British children have healthier teeth than American children.",
"The difference here is that dental healthcare for kids is covered by the NHS, but cosmetic dentistry isn't. Historically this means cosmetic work (bleaching, straitening) wasn't as common as it was in the US. ",
"Cosmetic work is becoming lot mor... |
[
"[Physics] Is there a \"2012 update\" on the double slit experiment?"
] | [
false
] | Hello all It seems that the latest years, especially this one, were especially exciting for physics in general. This piece of news, for example: or this (since I'm a layman, I can't really get it) so the question that I bring today is: are there updates (that can be explained to those who are not physicists) on the understanding of the double slit experiment? Extra question: were there advancements or changes in the understanding of the wave/particle collapse? Thanks! | [
"What a negative view of scientists. Some discoveries are actually quite sensational. "
] | [
"No and no. Scientists like to sensationalize their findings so that they get more grant money, and science journalists like to sensationalize their findings because it's easier than actually understanding anything. Our current understanding of basic quantum mechanical things like the double slit experiment is basi... | [
"I wasn't aware of this specific article you linked, but apparently there have been ",
"criticisms",
".",
"The first one is significant because they managed to protect a qubit from being influenced by 'noise' from its environment by using weak measurements and using the info gained from those to perform error... |
[
"Do people who are constipated absorb more nutrition from the food they eat because it spends more time in their digestive tract?"
] | [
false
] | Whether that be calories or micronutrients. | [
"Almost all of the nutrients in food have already been absorbed before it reaches the lower intestines/colon, etc. So no."
] | [
"Constipation results from food sitting in the large intestine, the colon, for too long. Large amounts of water get absorbed, and produce hard stools. Most of the food is already absorbed by then."
] | [
"No as other have mentioned, constipation is really more of an issue with water content and \"bulK of the stool than it does with nutrients."
] |
[
"What did the ground of the cretaceous period look like?"
] | [
false
] | I recently found out that grass isn't too old of a development, so I was wondering what dinosaur-period terrain might look like. Was it covered with different kinds of plants? Were valleys and rolling hills all dirt brown and sparsely vegetated? | [
"lots of Ferns and mosses made up the majority of the ground cover. ",
"http://www.botany.wisc.edu/courses/botany_422/readings/Graham1993.pdf"
] | [
"It is also worth noting that until the very end of the Cretaceous there were no ",
"flowering plants",
".",
"No cherries, lemons, limes, oranges, sunflowers, grasses (e.g. wheat, rice, maize, barley, rye), apples, pears, nuts, lilies, magnolias, orchids, palms, oaks, daisies, peas, pineapples, broccoli, pota... | [
"thanks!"
] |
[
"Does quantum entanglement allow faster-than-light information transfer?"
] | [
false
] | [deleted] | [
"No. Full stop.",
"Previous discussions:",
"http://www.reddit.com/r/askscience/comments/hcrkw/why_cant_we_use_quantum_entanglement_to_send/",
"http://www.reddit.com/r/askscience/comments/galfv/is_entanglement_faster_than_light/",
"http://www.reddit.com/r/askscience/comments/gb77k/how_is_entanglement_able_t... | [
"The article is incorrect, and I want to punch Geoff Brumfiel in the anus. There's a lesson here: science journalists don't always understand science.",
"While some people originally thought (many decades ago) that some information was being communicated, we now appreciate a more correct understanding of entangl... | [
"Everyone knows that the anus is the organ responsible for coming up with interpretations of quantum physics."
] |
[
"If all dogs came from wolves, how did we get so many different breeds etc?"
] | [
false
] | Like how do we have pugs and Aussies and all of that jazz? Might be a dumb question but I would love to know! | [
"Selective breeding.",
"In the beginning we didn't have \"dogs\", we had wolves that didn't attack us, and protected us, in exchange for warmth & food. With time, as humans spread around the planet, we started setting them to different tasks like guarding or hunting. And each generation ",
" chose which dog cou... | [
"You have clearly not seen a greyhound when it spots a squirrel haha that instinct is definitely there but why bother hunting when human feeds you for free?"
] | [
"There has been much less selective breeding for cats. They were domesticated like a farm animal, but didn't live as closely with humans as dogs do until very recently."
] |
[
"Why do electricity pylons make a loud buzzing sound?"
] | [
false
] | null | [
"Mains hum, electric hum, or power line hum is a sound associated with alternating current at the frequency of the mains electricity. The fundamental frequency of this sound is usually 50 Hz or 60 Hz, depending on the local power-line frequency. The sound often has heavy harmonic content above 50–60 Hz. Because of ... | [
"Contaminates (usually bird poop or salt spray) on the insulators cause arcing which you can hear. Frequently you can also see it at night, especially during high humidity. If this gets bad enough, the power company will wash the insulators--search youtube for \"hot washing insulators\".",
"A side note--you hea... | [
"I'm not OP but, despite your informative answer, I think you've sidestepped the (intended) question - why do (power lines on) electricity pylons make a loud buzzing noise? ",
"I understand your arguments about transmission equipment, mains hum, etc. but I too would like to know the mechanism by which the HT powe... |
[
"How does evolution work with chromosomes?"
] | [
false
] | All animals have a discrete number of chromosomes and can't reproduce with animals with a different number of chromosomes, right? So when an animal has a different number of chromosomes than its parent (as must have happened at some point), how does it reproduce? | [
"PZ Meyers has a pretty great explanation with pictures ",
"here",
". The short summary is that it is possible for two closely related organisms with different numbers of chromosomes to have fertile offspring. As the abnormal karyotype spreads and individuals with the abnormal number of chromosomes interbreed... | [
"Thank you!"
] | [
"Yes, animals will have different numbers of chromosomes, but there are examples of different species breeding and producing offspring that are sterile. See the example of breeding donkeys and horses: ",
"http://en.wikipedia.org/wiki/Mule",
"Evolution works on a smaller scale operating on the gene level by aff... |
[
"Why is glass such a good compound to store most chemicals in?"
] | [
false
] | I know some chemicals like HF can eat through glass, but in general most things can be stored in it without any reactions ir consequences. What properties does glass have that makes it so? | [
"As a chemist, I can tell you that basically nothing is kept in a metal container. The common choices are glass, for almost anything, polypropylene, which can be good if you have an acidic sample where you don't want the acid leeching metals out of the glass, or if you're dealing with HF. HF is really one of the fe... | [
"As a chemist, I can tell you that basically nothing is kept in a metal container. The common choices are glass, for almost anything, polypropylene, which can be good if you have an acidic sample where you don't want the acid leeching metals out of the glass, or if you're dealing with HF. HF is really one of the fe... | [
"See this thread and coniform's excellent answer.",
"http://www.reddit.com/r/askscience/comments/1894b8/why_is_glass_so_chemically_stable_why_are_there/"
] |
[
"Why do Chimps and Gorillas have insane strength and muscle mass?"
] | [
false
] | A couple of obervations of mine...I know there biology is different then humans but it seems Chimps and Gorillas eat poor nutritional greens and dont seem any more active then lets say a hunter- gatherer human lifestyle. Why did us humans go down such a different Evolutionary path? Why are the other Great Apes so damn strong? | [
"\"Biologists have uncovered differences in muscle architecture between chimpanzees and humans. But evolutionary biologist Alan Walker, a professor at Penn State University, thinks muscles may only be part of the story.",
"...Walker's hypothesis stems partly from a finding by primatologist Ann MacLarnon. MacLarno... | [
"Thin, lean bodies work very well for efficient locomotion."
] | [
"It sounds like ",
"this is it",
"."
] |
[
"Why do orbits always rotate over time?"
] | [
false
] | I'm referring to , when an object doesn't take the same path each orbit around another object. What causes this to happen? | [
"That needs some context, orbits don't usually do that. The orbit of a perfectly spherical object about another perfectly spherical object will, when viewed in the reference frame of one of the objects, always have apsides in the same two locations. In the real world, planets, stars, and some moons are oblate spher... | [
"The orbit of a perfectly spherical object about another perfectly spherical object will, when viewed in the reference frame of one of the objects, always have apsides in the same two locations.",
"Isn't this only the case for Newtonian orbits? Wasn't the reason why ",
"the perihelion precession of Mercury",
... | [
"That's correct. In a general relativity framework, the periapsis of an orbit is subject to the geodetic effect and the Lense-Thirring effect. These come from the rotation of the bodies."
] |
[
"Why Don’t we have fusion power yet?"
] | [
false
] | I was just wondering why we don’t have fusion power yet. I know that right now the reactors are highly inefficient but I was wondering if there was a specific reason? Is it the material that the reactors are made of or the amount of hydrogen and deuterium and tritium needed. | [
"ITER should be finished before 2025 (if things go relatively well) it will be the first complete industrial sized fusion reactor in the world. It's not supposed to be used to supply france's grid but for research purposes as à way to fine tune à reactor of this size.",
"It should theorically provide 10x more ene... | [
"Tl,dr : industrial pilots are under construction",
"ITER is not an industrial pilot. It's 100% a research experiment. The industrial pilot will be called DEMO, which will be designed once ITER is up and running, taking into account everything that was learned from the construction and operation of ITER."
] | [
"Fusion generates a plasma so hot it would vaporize any material it touched. Controlled fusion therefore requires building a \"force field\" to hold the plasma. In modern parlance they tend to call it a \"magnetic bottle\". Since the particles of plasma are electrically charged, a magnetic field can, in theory, kee... |
[
"Do batteries change in mass at all when charged?"
] | [
false
] | null | [
"Not significantly assuming the battery we are talking about is a closed system there will be a tiny weight difference because a charged battery has more energy and e=mc",
" But in practice you can't measure this. ",
"Some batteries however bind oxigen from the air when discharged these batteries are actually s... | [
"Math!",
"An 18650 li-ion battery weighs ~50 grams and stores around 11 Watt-hours of electricity. That's about 3,600 joules, which has a mass of 40 picograms, about the same as a small bacterium. It gets a trillionth heavier when its charged."
] | [
"A lithium-ion battery is a sealed system (bad things happen if it is punctured) so it should not gain or lose any nucleons during a charge-discharge cycle. It also shouldn't gain or lose electrons as electricity always flows in a complete circuit; an electron cannot leave the cathode without another electron enter... |
[
"How strong is an electromagnet when it's not on?"
] | [
false
] | I work with a 3T magnet. It still has some magnetic field present even when there's no current turned on, right? How strong is that field? | [
"Well, most MRI magnets have superconducting wires cooled by liquid helium, which is more expensive to start up but uses much less electricity. You can only turn off the magnet by draining the helium, which is really really expensive so it's only done in case of emergencies, like the patient forgot to mention he ha... | [
"It really depends on the magnet. From the sounds of it, you have a magnetic core wrapped in wire? In that case the iron core still has a magnetic field. Is it an MRI magnet? Is that case it should probably never be turned off"
] | [
"Superconductivity leads to the wires having zero resistance, so once you get the current going at temperature, you short the circuit and you have a constantly flowing current (i.e., an electromagnet that stays on).",
"Draining the helium will heat the wires above the critical temperature, in which case the magne... |
[
"Is it possible to have a \"personal processing unit\" to carry around and help our devices process information?"
] | [
false
] | Hey Scientists of Reddit, I've been wondering this question for a while now and I just wanted to know if anybody has any insight on this. Some people's phones are a bit out of date and using a personal processor would help out with the processing power needed to keep up with apps that demand a lot more power to process. This could lead to other awesome applications for this technology. I've been fiddling with the idea that the processor could process the information and pass the already processed information through bluetooth to other devices. I'm not a computer expert and my expertise lies in software, so I thought maybe the scientists of reddit could shine some light on this idea. Thanks for reading :) | [
"The idea isn't ridiculous but...",
"Quite a lot of effort goes into keeping up with a processor - the memory and interface components are tied directly into the processor with dedicated high-bandwidth channels.",
"While a second processor can be useful in some circumstances, the data bandwidth between processo... | [
"I'm not sure exactly what you mean. A computer processor (in your phone, tablet, or whatever) needs to be connected directly to hundreds of other elements in order to function correctly. ",
"Are you suggesting an extra processor like an extra battery pack? that could be plugged in as needed? Processing power is ... | [
"I guess I worded the idea wrong. I was imagining a device which has memory, processor, and a way to \"plug into\" it. I was imagining that this would allow for peripherals to be used instead of all of our devices to have their own dedicated processor.",
"Thank you for your response"
] |
[
"Another paradox within 'the twin paradox'?"
] | [
false
] | The paradox that the is named for isn't a true paradox, since it's based on the false assumption that both twins would age the same because each twin sees the other moving. However, considering the effects of time dilation as it becomes more extreme, I can't help but feel that a different sort of paradox arises. I'll give an example. Twin A departs from the location of Twin B in a spaceship that quickly accelerates to 0.995c. This would give a time dilation factor of just over 10, so for every second that passes from A's reference frame at this speed, just over 10 seconds would pass for B. Let's say that A does a short round trip of 10 lightseconds before quickly accelerating back down to being stationary right next to B again. From B's perspective, the journey would appear to have taken barely over 10 seconds, since A was traveling only half a percentage point below c. When considering A's perspective however, things seem to become paradoxical. According to special relativity, those ~10 seconds as experienced by Twin B would be for Twin A only experienced as ~1 second -- even though A has covered a distance that takes light 10 seconds to travel! Am I interpreting this correctly? Because it seems in this scenario that A would have had the experience of traveling at around 10 times the speed of light. Could it be a real consequence of special relativity that the faster you travel, the faster you to travel from your own perspective? If true, that would mean that an arbitrarily long journey could be experienced as taking place within an arbitrarily short amount of time if you were traveling a significant enough fraction of the speed of light. Or am I just seriously misunderstanding something about the effects of time dilation? EDIT: SOLVED - Thanks to all who replied! I hadn't considered that Lorentz contraction would actually allow this to happen. My mind is so blown. | [
"A would also experience length contraction, so that it would appear to him that he was only going 1/10th as far as B observes him to travel.",
"that would mean that an arbitrarily long journey could be experienced as taking place within an arbitrarily short amount of time if you were traveling a significant enou... | [
"Essentially, yes. People misunderstand that a lot, but given enough energy, you can reach everywhere in an arbitrarily short amount of time (well, there's some practical concerns), all according to relativity."
] | [
"Yes, this is true.",
"The implications of that are mindblowing! With enough speed, you could travel any number of lightyears and also arrive at a point nearly as many years in the future, in just seconds. Provided you have an astronomical amount of energy and don't run into some cosmological horizon like the e... |
[
"A few questions about telescope technology and the expansion of the universe"
] | [
false
] | [deleted] | [
"Back in the 1990s, Silicon Graphics created a hardware-based random number generator using — I am not making this up — a lava lamp."
] | [
"Back in the 1990s, Silicon Graphics created a hardware-based random number generator using — I am not making this up — a lava lamp."
] | [
"1) Current data indicates that the metric expansion is accelerating.",
"2) Those radii correspond to times before the epoch of last scattering, which means that any light emitted during those periods was absorbed before it could traverse space; the universe was opaque.",
"3) The oldest we can see is light that... |
[
"How do astronomers know that the tiny 4 pixel dot on their photo is a galaxy and not a star?"
] | [
false
] | null | [
"photometry",
" and/or ",
"spectroscopy",
", because a (red-shifted) galaxy will have a different ",
"spectral energy distribution",
" from an individual star"
] | [
"Even very distant galaxies will often appear a bit more spread out than stars. By looking at all the dots in the image you can model a point-spread function for that image and see if a particular object is a bit more extended (or fuzzier) than it should be, even if they appear identical to the human eye.",
"But... | [
"I believe astronomers can “decode” the light being emitted by an object, and can deduce the components of that source of light through a tool called a spectroscope. Knowing which elements the light source is composed of probably gives scientist a better idea of what they are looking at. ",
"This was all from my ... |
[
"Is the natural state of human eyelids open or closed?"
] | [
false
] | I'm curious how the muscles in the eyelids works. When the muscles in your eyelid are relaxed, does that make your eyelids open or closed? I know if you die and your eyes are open, they stay open. When you are asleep you don't have trouble keeping them closed. I feel like the natural state should be open, but then why aren't there large numbers of people who suffer from their eyes opening while asleep? | [
"There is no natural state of the eyelid. That's like asking what's the natural state of your elbow, straight or bent?",
"The eyelid is closed by a muscle called the ",
"Obicularis oculi",
". It has an antagonist (or opposite pulling muscle) called the ",
"Levator palpebrae superioris",
" that opens the... | [
"Actually levator palpebrae superioris ",
" the eyelid, and obicularis oculi ",
" the eyelid. ",
"From what I remember, obicularis oculi is really several muscles that are continuous. One part of it is constantly contracted (not under conscious control) so that when you sleep your eyes will remain closed. The... | [
"Perhaps what you mean by \"natural\" is essentially ",
", as in, no muscle contraction. ",
"If that is what you mean, then there really is no natural state since at any given time at least one of the muscles acting on the eyelid is contracted, with or without your conscious will to control it. ",
"In fact, m... |
[
"Could a sufficiently cold planet have real, flowing, liquid rivers of matter that is usually gaseous on our planet, such as nitrogen?"
] | [
false
] | What could its atmosphere be made of then? Could it rain or snow this "gas"? | [
"I can see some future cosmic redneck launching a flare into the atmosphere saying 'hey check this out'.",
"Is there enough oxygen for anything to happen from that? If not, would a source of flame built for use on Titan just carry an oxidizer and use the ambient atmosphere for fuel? Like an inverse of how we don'... | [
"To add to this, we have seen features on Titan that are almost certainly created by precipitation. The only thing that fits what we know with Titan's atmosphere is if the methane itself is precipitating. There appears to be a full weather system analogous to that on Earth, but with methane instead of water."
] | [
"To add to this, we have seen features on Titan that are almost certainly created by precipitation. The only thing that fits what we know with Titan's atmosphere is if the methane itself is precipitating. There appears to be a full weather system analogous to that on Earth, but with methane instead of water."
] |
[
"Would living on Mars over many generations, away from Earth’s environment cause our autoimmune system to be virtually nonexistent ?"
] | [
false
] | null | [
"Biology "
] | [
"Biology "
] | [
"Such hypothetical / speculative / open-ended questions are better suited for our newish sistersub ",
"/r/asksciencediscussion",
". Please post there instead."
] |
[
"How does diesel not combust in the high pressures of the high pressure fuel pumps of modern diesel engines?"
] | [
false
] | I know the pressures in most modern diesel engines for fuel rail pressure seem insane to a normal person, I know the one in my VW is something like 18,500 psi. That strikes me as higher than most of the pressures achieved in the cylinder. So that seems like it should be an issue but it isn't seeming to be. | [
"In this technical paper",
", P_max in a diesel cylinder is 180-200 bar (2600-2900 PSI)",
"However, in the cylinder it's a mixture of diesel ",
" that is compressed. Combustion needs oxygen! If the fuel pump is compressing just diesel by itself, it's not going to combust at any pressure because there's no oxy... | [
"All materials are compressible, their compressability just varies by many orders of magnitude.",
"Even things like steel and other metals compress with sufficient pressure (Terapascal range)."
] | [
"There is no oxidizer (air or otherwise) in the fuel injection system - no way for the fuel to burn."
] |
[
"Can anyone help me with a modulus operation?"
] | [
false
] | null | [
"First consider 5555",
" mod 5555. What number is this? Then look at 5555",
" mod 5555. Then 5555",
" mod 5555. Are you seeing a pattern emerge?"
] | [
"They all equal zero. What does that mean?"
] | [
"I got a hold of my classmates who walked me through the same thought process. I feel dumb now, but thank you :)"
] |
[
"How can we understand where we are in our galaxy since we cannot see it from \"top down\"?"
] | [
false
] | This made me wonder this question. If we are in the disc, how can we be able to see past the center of our galaxy to know what lies on the other side, let alone where we are? | [
"Here are two very few basic clues we can use. First, ",
"we can see the Milky Way",
" from Earth pretty clearly. If we were near the interior it would be all around us (and much brighter). Second, we can look at the distribution of stars and their relative distances to determine a general map of where every... | [
"That being said, it is extremely difficult to determine where we are in the Galaxy, with any precision. For example, the distance from us to the Galactic center has been the subject of controversy for many years, see for example ",
"this low-level review",
" of the subject. With the advent of sub millimeter ... | [
"I have a question that goes along with this. How do we know the Milky Way is a spiral bar galaxy and not some other type?"
] |
[
"What would happen to forests if there were no wildfires?"
] | [
false
] | [deleted] | [
"Hey. I have a bachelors degree in rangeland management. It has a lot of overlap with any wildlands.",
"This question isn't necessarily as straightforward as It might seem. Different forests, and range lands have different fire regimes. And it all depends on fire return intervals. ",
"In Florida some fores... | [
"Fire effects on forests vary hugely depending on forest type and fire type. Specific examples of different fire regimes:",
"Temperate rainforests (e.g., west coast of Canada and southern Chile): fire is not common and the ecosystem is not fire-adapted.",
"Conifer forests in the dry western US: ",
" fires are... | [
"For clarification I am neither a scientist or a forester. I do read a lot so have some unscientific information. First some species of trees only release seeds when they are in a fire situation so those species wouldn't propagate. \nSecond it was the policy of the federal and the state government for years to acti... |
[
"Protein shakes for muscle gain. Are they needed?"
] | [
false
] | So I have a friend who is trying to put on a little muscle. Running and doing regular weight training. She has recently purchased pounds and pounds of these protein shakes that claim to boost muscle gain. I was wondering if there's actually any scientific evidence to suggest that it'll actually help. My gut is telling me that just eating a nice healthy balanced diet (which she does already ) will be enough in itself and that her body will get enough protein from that alone. I just don't see the point in wasting money on the stuff if it doesn't work. Thanks in advance for any help. | [
"Protein shakes just help you get the amount of protein you need without having to eat whole chickens everyday. You can get anything in a supplement from food. They just provide an easier way to get it."
] | [
"It's like any other food. If eating protein shakes helps them get their daily protein intake, then it would be relatively equivalent to getting their protein from other sources."
] | [
"Why is that? "
] |
[
"Should you keep moving or stand still in freezing water?"
] | [
false
] | I just recently watched the Titanic and it got me thinking about being in freezing water (around 4°C). Should you try to be still and increase the temperature of the water around you or is it better to try and swim towards the nearest rescue boat? I'm guessing that your body isn't able to increase the surrounding water that much and it's therefore better to keep moving? Any heat transfer experts want explain the pros and cons? | [
"You should get the fuck out of the cold water.",
"You are correct, that in still (or mostly still) water, you will lose less heat if you keep still. Moving will on the other hand produce body heat.",
"However, cold water will push you into hypothermia quickly mostly independent of how much you move which you g... | [
"or should he have done what he did, which is nothing?",
"Well obviously sitting there and dying isn't a good plan. He could have looked for more wreckage, maybe a piece of ice, or even pushed the door around."
] | [
"If you can swim safely somewhere and get out of water you should do that. Otherwise you should not remove any clothes, you should always keep your head out of the water and you should cross your hands over your chest and your legs together, in order to lose as little body heat as possible. Also you can use your cl... |
[
"Why are triangles the strongest shape?"
] | [
false
] | null | [
"Given any three lengths, there is at most one triangle whose sides have those lengths. ",
"Presumably, the weakest part of a shape will be the joints, so if you have any shape and you put a force on it then it will likely prefer to deform at the joints than someone along one of the sides (not an engineer, just u... | [
"Good explanation. I would add that for some designs, triangles are not the strongest shape. They are great for making trusses and towers, but make terrible pressure vessels. "
] | [
"It's not that joints are weak, but that you don't want to be applying bending loads at them, because, like a lever, the distance magnifies the forces seen by the distant joint. With a triangle, you are converting the load applied at one corner to compressions and tension of the sides, and counter forces at the oth... |
[
"How did they figure out antidotes to poisons?"
] | [
false
] | Did they just drink different poisons and try various things and hope they didn't die? | [
"Traditionally, that's probably not too far off the mark. I modern medicine, we know what we're doing though. In the case of each toxin, we can pretty quickly figure out its mode of action.",
"Most poisons tend to fall into broad categories. E.g.: there's broad metabolic poisons such as heavy metals, hemoglobi... | [
"Basically, since we understand chemistry well these days, it's pretty straightforward to design antidotes to poisons once we understand them.",
"Is it really so easy? Drug-discovery chemistry in other areas of medicine is very, very, very hard. With other diseases and disease processes, our understanding of bioc... | [
"If I had to guess I'd say being poisoned is more like stopping a bullet but diseases are more like fighting an all out war. If you can soak up enough of the toxin to make it non lethal you'll live. If you stop a bullet in the scheme of the war you've still got other stuff to deal with right afterwards."
] |
[
"If the liver can regenerate, how do people die from liver failure?"
] | [
false
] | null | [
"Liver failure can happen in two ways. First, the acute damage can simply be too serious for liver cells to deal with before the person dies. Second is a more protracted process, where damages accumulate.",
"Suppose that the liver has taken damages from infection/drug/alcohol/etc. ",
" Scar tissue is tougher th... | [
"In cirrhosis, the fibrosis is diffuse, prohibiting surgical removal of scar tissue.",
"Fatty liver (steatosis) is essentially reversible but once the fibrous tissue forms, the extracellular matrix (the microscopic scaffolding outside the cells) no longer supports regeneration and the process is generally conside... | [
"So if a liver is scarred, is a solution sometimes to cut away the scar tissue to stimulate new growth?"
] |
[
"Can crocodiles mate with alligators?"
] | [
false
] | [deleted] | [
"No, they can't. They may look similar, but they're quite distantly related, and they diverged a long time ago. Alligatoroidea and Crocodyloidea, the larger groups that contain modern alligators and crocodiles, respectively, extend back into the Cretaceous. However, lots of different croc species can successfully ... | [
"Not to mention all the ",
"gamebird hybrids",
". Pheasants and chickens make some wacky hybrids. That article says they've even hybridized with chachalacas and guans, which are in a different family (Cracidae). I can't find a source for that, though. Birds have some ",
"crazy hybrids",
". Lots of cockatoos... | [
"It's ",
", so you're not conserving the species. Hybridization is a mechanism for speciation. From a conservation perspective, if the hybridization is not a natural occurrence, it's generally not going to be what you want. There are exceptions, such as when genetic diversity is so low that a species isn't viable... |
[
"How much influence do stochastic occurences have on the process of diffusion, and how much do deterministic?"
] | [
false
] | null | [
"Your question isn't clear - what do you mean by \"deterministic processes?\" Generally, processes at the molecular scale are all stochastic once you look closely enough."
] | [
"I am sorry if I didn't word my question correctly. By 'deterministic processes', I meant steps in the diffusion process that are governed by deterministic laws. "
] | [
"Hmm, ok, this question might be more of a physics question then, something to be tackled by statistical mechanics. ",
"I guess you might mean processes liike directed diffusion along an electrochemical gradient? "
] |
[
"Are modern humans stronger or more athletic than our pre-agricultural counterparts?"
] | [
false
] | null | [
"There is an argument using evolutionary theory that agriculture was only adopted to increase group fitness at the cost of indivual fitness.",
"Lots of civilisation diseases started with the adoption of agriculture.",
"So there is the argument that agriculture made civilisation possible but at the cost of pure ... | [
"It depends on your viewpoint of the agricultural revolution and how you define stronger. Until very recently (within the last 200 years or so), the switch to agriculture had an overall negative impact on human health (Diamond 1987). Evidence for this can be seen in studies from western Ukraine on the Trypillia-Cuc... | [
"It's an interesting way to look at it but I struggle with language that suggests something occurred \"to\" achieve something else... which is language that often seems implicit in evolutionary theories.",
"",
"It could also be argued that the development of agriculture starts to take us out of \"Natural\" sel... |
[
"With all the tiny particles in the air (dust etc), do they accumulate in our lungs or anywhere in our body, and how does our body dispose of it?"
] | [
false
] | Currently laying face first on my pillow when I was struck with the thought | [
"The particles don't often make it into your lungs. Your nose is lined with hairs called cilia, these trap and filter out most particles, its why we have snot. The sinuses give the nose more time to filter out these particles as they travle down towards the trachea, and again, anything deposited in all but the sm... | [
"Our lungs do indeed have a mechanism for 'self-cleaning' to get rid of foreign dust particles and microbes etc. This is called ",
"Mucociliary clearance",
" ",
"The components of your respiratory tract from your nostrils to your trachea to your bronchi (although not your mouth) are lined with tiny hairs call... | [
"Smoking damages/kills some of the cilia and makes this process of filtering incoming air much less efficient. So, long story short, yes."
] |
[
"If an infinitely powerful computer had a complete snapshot of the universe, by which I mean every possible datum about every bit of matter or energy, could a perfect simulation accurately predict the future, or is there some intrinsic randomness in the system?"
] | [
false
] | null | [
"This question has been asked, and it is known as ",
"Laplace's demon",
".\nUltimately you are asking if knowing fully the state of the universe at one time you can then predict the state at all future times.",
"In short, the answer is \"no\". You can make that argument in several ways, either through thermod... | [
"You would however be able to assign a probability distribution over all possible futures.",
"Of course, it's important that this computer not be a part of this universe, or it would also have to simulate itself, simulating itself..."
] | [
"Heisenberg's uncertainty principle",
" would make it impossible to predict the future. Indeed as I understand it, it would even make it impossible to have an infinitely precise model of the current state of the universe.",
"In particular note:\n\"the uncertainty principle actually states a fundamental property... |
[
"How does immunotherapy (allergy shots) work when regular exposure to pollen doesn't?"
] | [
false
] | I've searched this and every site gives some unhelpful answer about injecting the irritant and building up a tolerance. But we suffer from allergies every year and don't build up a tolerance. Is there something special about the delivery mechanism? The substance delivered? The exact dosage? Could I sniff exactly the right amount of tree on exactly the right schedule and get the same effect? | [
"That is an interesting question.",
"The exact mechanisms are unknown but the dominating theory is that the immune system switches from always releasing a lot IgE antibodies into the blood to producing more specific T-cells, which reduces allergic symptoms.",
"So could you recreate that at home? Sadly not, beca... | [
"Allergen immunotherapy is NOT a quick fix. You are typically committing to years of therapy.",
"The intent is to receive just barely enough to \"stimulate\" your immune system without causing a full-blown immune response.",
"Simple analogy: training for a marathon. You run a little bit further every day to b... | [
"You want to have tiny shots that DON'T trigger a response. Note: can also be oral tablets or skin swabs.",
"Each time you trigger a response you are basically resetting back to the start.",
"Analogy time (2): lifting weights to build muscle. You want to continuously lift small weights and build up to heavier... |
[
"How does Skype know not to send the sound of my own voice back when it is picked up by my friends mic.?"
] | [
false
] | null | [
"Skype, along with just about any telephony system down to and including the analog telephone system, has to do \"echo canceling\" so you don't hear your own voice. This is actually a REALLY hard problem, from a signal processing point of view, but it's so well studied that it's largely a solved problem at this poi... | [
"It's even more complicated, because the sent voice re-recorded will not just be altered by the microphone properties, but also by the speakers and the room's acoustic properties. Just subtracting the pure source sound at the right time-position would still leave all these alterations in place. That's an insanely c... | [
"At the heart of echo cancellation is cross-correlation. Basically you're looking for how similar your incoming sound is to the outgoing sound, once you find the offset of cross-similarity you can attenuate the echo. You can do this on the spatial domain [e.g. looking at PCM samples] or on the spectral domain [lo... |
[
"What causes a “brain freeze” when eating ice cream or drinking something cold fast?"
] | [
false
] | null | [
"Well vasoconstriction is involved but it definitely is not the carotid arteries. If that was the case, we would have mini-strokes every time we ate some really cold. ",
"",
"What actually happens is there are capillaries on your palate which vasoconstrict when something really cold comes in contact. This isn'... | [
"Well vasoconstriction is involved but it definitely is not the carotid arteries. If that was the case, we would have mini-strokes every time we ate some really cold. ",
"",
"What actually happens is there are capillaries on your palate which vasoconstrict when something really cold comes in contact. This isn'... | [
"And put your tongue against the roof of your mouth, it warms the blood vessels there."
] |
[
"Why were animals so large in the past (Giant Sloth, Giant Leatherback Sea Turtle, other giant animals) but so small now?"
] | [
false
] | null | [
"The AskScience FAQ has some lovely things to say on this topic! ",
"Weren't insects huge in the past because oxygen levels were higher?",
" ",
"Could a dinosaur breathe in today's atmosphere? Weren't animals bigger when there was more oxygen to breathe?",
" ",
"Why are animals smaller today than in th... | [
"This comment has been overwritten by an open source script to protect this user's privacy. It was created to help protect users from doxing, stalking, harassment, and profiling for the purposes of censorship. ",
"If you would also like to protect yourself, add the Chrome extension ",
"TamperMonkey",
", or t... | [
"Giant sloths lived ~10-15k years ago. The air isn't that different. It has more to do with habitat and food supply."
] |
[
"People talk about \"wasting\" water when we run the taps - is that a valid description of how water & sewage systems work?"
] | [
false
] | Clarification: I live in a Northern Ontario town with reasonably abundant fresh water. Most of our drinking water comes from two lakes. I'm under the assumption that, once the water leaves a house and goes back into the sewage system, it's treated and released. If that's correct, do we really "lose" the water? I'm sure the system isn't totally closed and therefore some of the water is lost (leaked, evaporated, etc.) But I'd imagine that most of it is reusable. | [
"It takes energy to turn dirty water into clean water; while the system is mostly closed quantity-of-water-wise, it is not energetically closed. If you are in an area where water is not supply-constrained, then using too much water is not causing someone else to have a shortage, but it is contributing to the carbon... | [
"I'm from Los Angeles. We source our water from 500+ miles to the north, which has nearly destroyed several ecosystems, notable the Owens Valley and Mono Lake (see ",
"photos",
")\nAfter it goes down the drain, LA water is treated and flushed into the Pacific. It never recharges the water table up north- that's... | [
"I can see that having to ",
" all that clean water between the tap and the treatment plant would increase the energy cost, but how big is the impact on actual treatment? In other words: How much does the energy cost of water treatment depend on ",
" versus ",
"?"
] |
[
"What do irrational numbers \"mean\"?"
] | [
false
] | An irrational number is one that can't be represented as a fraction of two integers, but how is this reflected in real terms. I.e. 1.7 is one whole plus 7 out of 10 pieces of another whole. But is there any way to describe irrational numbers in terms like that? I can only imagine a whole object being divided infinitely, but I don't know how this would exist on real life. I hope this question makes sense. | [
"This is a very good question that deserves a very careful answer. This is going to be a long post, because I'm going to go into quite a bit of detail and using the simplest terms.",
"In order to understand an irrational number, it is very important to realize that this is just one level in a whole hierarchy of n... | [
"If you can measure 1 inch with enough precision you can measure sqrt(2) inches with the same amount of precision: First construct a square with side lengths of exactly 1 inch (using your precise 1-inch ruler). Then cut the square in half along the diagonal, giving you two right-angled triangles. The lengths of the... | [
"You can not measure any physical length with infinte precision. So you can never measure a length to be exactly sqrt2 inches, but you can't measure something to be exactly 1 inch either.",
"For physical measurements, you can only measure up to some accuracy, so I am not really sure what you mean. Your zooming in... |
[
"Why are the racks for test tubes 6x12 and 6x6"
] | [
false
] | I find this highly illogical in impractical and it seems no one can provide me with an answer as to why this is. | [
"Don't underestimate the power of \"it's always been that way\". Before metric was adopted, a \"dozen\" was often used as a unit. Eggs still come in dozens in many places, for instance.",
"Test tubes have been around for a LONG time, and after a university has invested in racks that hold them, of a specific siz... | [
"All my test tube racks are 4x10 or 5x12. Perhaps that's all you see because that's all your school/company buys."
] | [
"That is just the size you're used to seeing wherever you do science. My lab uses lots of 4x10 and 4x5 racks. In grad school we used 8x12 all the time. "
] |
[
"Why does scratching an itch make it stop itching?"
] | [
false
] | Well, ive wondered this for awhile now. I appreciate any answers :) | [
"You may want to check out ",
"this",
" story. Not exactly scholarly but still interesting.",
"A brief synopsis (from my memory of reading it a few years ago) is that the brain might create some itches when it lacks sensory data from a region of the body. By forcing the hands to that area, in order to itch, i... | [
"It's a reward for following instructions. ."
] | [
"This seems right to me, anyway. The skin sends out an itch signal when it detects any sort of external parasite. Scratching is a behavior tailored to remove parasites. Scratching relieves the itch and (hopefully) removes the parasite in the process. If anyone has data on this, please chime in, I don't have tim... |
[
"Are the superheavy elements well-mixed in the galaxy? Are there \"nuclear deserts\" where one might find the heaviest things (tellurium) absent?"
] | [
false
] | null | [
"To answer this, you must first consider the way different elements form in the first place - information that, fortunately, SDSS has compiled in this graph of the periodic table:",
"https://upload.wikimedia.org/wikipedia/commons/thumb/3/31/Nucleosynthesis_periodic_table.svg/2560px-Nucleosynthesis_periodic_table.... | [
"Other than us being far enough from the galactic core for planet sterilizing astronomical events to be rare, but close enough for heavy elements to have some abundance, I haven't seen anything specific.",
"But it is really difficult to do detailed compositional analysis of every type of object in the Galaxy, and... | [
"Well, titanium is listed as .44% of the composition of the Earth, or 4,400,000 parts per billion. But it comprises only 3,000 parts per billion of the universe at large. (Both figures according to wikipedia.) So Earth has over 1,200 times the titanium we should compared to the universe as a whole. But this shouldn... |
[
"What are quarks?"
] | [
false
] | My friend insists that quarks, leptons and bosons fall under the category of "quarks", while I say that quarks are their own subcategory, along with leptons and bosons, under the larger category of "subatomic particles". Who's right? | [
"First you have the fundamental particles. They divide into two main families based on their property of \"spin.\" Integer-spin particles are bosons, and half-odd-integer spin particles are fermions. Fermions have the property that no more than one can occupy any given state, so they form the structures that we thi... | [
"Yes, those are three distinct categories of sub atomic particles.",
"However, I think you mean \"gauge bosons\" or \"force mediators,\" both of which are used to describe the bosons in the standard model. The term \"boson\" is more general than you imply."
] | [
"Yeah I showed my friend this, he still doesn't believe me.",
"EDIT: I absolutely love your username btw"
] |
[
"Communicating to past/future self?"
] | [
false
] | null | [
"Frequency of what? You can comminucate with you future self by just leaving a written/recorded message. They just can't answer back."
] | [
"All organisms are made out of atoms and molecules, which means literally every living thing is radiating energy and vibration. Every living thing on earth vibrates at its own level with its own sound, determined by the velocity of its frequency. So what I’m getting at is maybe there is a way that we can find a fre... | [
"All organisms are made out of atoms and molecules, which means literally every living thing is radiating energy and vibration. Every living thing on earth vibrates at its own level with its own sound, determined by the velocity of its frequency.",
"That's all more or less correct. You can listen to sound emitted... |
[
"Did scientists notice empirical deviations from classical mechanics or classical electrodynamics before Einstein offered a theory to extend them?"
] | [
false
] | In other words, did scientists already think something was wrong with their theories? Or did they assume measurements were reasonably predicted by those theories? | [
"Yes. A good example is the ",
"Michelson Interferometer",
". There was a belief before relativity that there existed some absolute frame of reference against which all velocities could be measured -- some sort of cosmic \"ether\" in which everything was embedded.",
"By interferometry you could determine the ... | [
"Astronomers observed there was a mismatch between Mercury's actual orbit and its orbit as predicted by Newtonian physics. Because a similar mismatch had predicted the presence of Neptune before it was observed, ",
"one explanation was the existence of a planet even closer to the Sun than Mercury",
", but relat... | [
"The aether represented a specific model. That model was proven wrong. If it so happens that a modified aether model can explain things, it is no longer an aether by definition, but instead some new idea that was inspired by an aether model. "
] |
[
"Does the electromagnetic force have a similar affect on space-time as gravity?"
] | [
false
] | Or any other fundamental force. If not why is gravity the only one; and consequently identified as a “fundamental force”, when it would be more appropriate to call it a mere side effect of Existence? | [
"Yes, for a certain definition of \"similar\". The space-time curvature is related to the total \"stress-energy\" in a volume, and the EM force is part of that stress-energy. But most realistic densities of EM energies are very very tiny compared to gravity.",
"As for \"mere side effect\" ... I don't see what the... | [
"If not why is gravity the only one",
"Go the opposite way: Find all ways a force can be described as change in spacetime. It turns out they all look like gravity. They don't have to look exactly like general relativity but they all lead to the same result in everyday life: A force proportional to the masses and ... | [
"So since the em force is 10",
" times stronger than we should only need a 1/10",
" the mass to generate black holes with pure magnetism? This doesn’t seem to be right, because this would have been done by now surely.",
"If gravity alone is responsible for the bending of space time, then it would seem this do... |
[
"Lobsters supposedly show no measurable signs of ageing and only die from external causes. Can we use this to increase the life-span of humankind?"
] | [
false
] | Repost from . I didn't quiet get the answer I was looking for. Is it possible and why/why not? | [
"It's thought that ",
"lobster longevity",
" is related to very high levels of the enzyme ",
"Telomerase",
"(",
"1",
"). By ",
"changing the levels of telomerase expression",
" in mice, ",
"it's possible to manipulate their longevity",
" (",
"2",
"). This is being looked into as a potential ... | [
"Turritopsis!"
] | [
"Lobsters and selective other animals are considered negligible senescent, as far as we know do not display the typical signs of senescence. Humans age and die due to cell senescence and the failure of body systems (ultimate cause of natural death would be failure of organs). I don't think anyone knows why lobste... |
[
"Why is Thorium three times more abundant than Uranium in Earth crust but it's radiation doesn't affect us much?"
] | [
false
] | null | [
"Uranium's radiation doesn't really affect us. The alpha particles it emits are easily blocked. Uranium's first use was in glassmaking: it adds a brilliant fluorescent green colour. In fact, depleted uranium emits so little radiation that it's an effective gamma ray shield due to its density. The main problem in te... | [
"Natural Thorium is mainly Th-232, which has a half life on the order of ten billion years; Natural Uranium is primarily U-238 with a half life of about four billion years. Even excluding their relatively low abundance, these long half lives mean they have a low activity and don't really make too much of a daily r... | [
"Thanks!"
] |
[
"The situation with bee Colony Collapse across the world: Have bans against certain pesticides made an impact?"
] | [
false
] | I'm not fully informed on the topic, but to my understanding, EU banned certain pesticides and the US have not. What's the 2021 situation on pollinators in the EU vs the US? | [
"Neonicotinoid pesticides are seen as the most problematic for bees. The EU ",
"banned",
" the use of neonicotinoids on pollenator-attracting crops in 2013, and in open fields in 2018. However, there have been some significant ",
"loopholes",
", thus the risks to bees are ",
"persisting",
", but the pop... | [
"The Genetic Literacy Project is a corporate front group that was formerly funded by Monsanto. So excuse me if I don't take it as gospel that there chemicals aren't killing bees."
] | [
"The Genetic Literacy Project is a corporate front group that was formerly funded by Monsanto. So excuse me if I don't take it as gospel that there chemicals aren't killing bees."
] |
[
"Why does salt water dehydrate you when salt helps you retain water?"
] | [
false
] | null | [
"Part of the problem is, seawater is really salty, about 3.5% salt by weight. An 8 oz (227 g) serving of seawater contains about 8 grams of salt. That's a lot of salt! The recommended maximum per day for sodium is 2.3 grams, which corresponds to 5.8 grams of NaCl table salt, about the same as in 1 teaspoon.",
"By... | [
"Thanks for explaining the answer in a more understandable way than found though the Google."
] | [
"about 0.9% salt by weight. ",
"Er, NS IV fluid 0.9% NaCl, but your body has many more solutes. the osmotic pressure of your serum is the same as normal saline, but the solutes are a cocktail of ions and organic molecules."
] |
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