title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Why is the inner core of the earth a solid whereas it's adjacent layer is a liquid?"
] | [
false
] | null | [
"The temperature within the inner core is too low to melt the Iron-Nickel alloy under the pressure which exists at that depth (> 5100 km below the surface of the Earth).",
"However, at shallower depths (2900-5100 km underground) the decreased ambient pressure lowers their melting points so the iron and nickel liq... | [
"As time passes the liquid stratum solidifies, meaning that in the future the Earth will no longer have a magnetic field, right?"
] | [
"Well, before that happens, the Sun is going to be stressing the biosphere. It's luminosity increases by something like 1% every 100 Myr. So that'll cause changes long before the magnetic field becomes a problem."
] |
[
"There are two 1-mile loops. One is totally flat. The other is uphill/downhill, but the net elevation is 0. Does the hilly one take more energy to run?"
] | [
false
] | If so, why? | [
"of course, the hilly one requires more energy to run.",
"when you run, you expend more energy going up hill, for all the reasons you would imagine--overcoming gravity to elevate your mass uphill. On the downhill side, too, your body is actually now also maintaining balance to keep you upright, using different mu... | [
"No, you're not a machine that coasts downhill. You expend more energy up and down than running flat. "
] | [
"If your body was a sphere, and our world were friction-less and loss-less, both would require zero net-work to complete. To calculate the work needed, we would take a line integral of the product of force and the infinitesimal distance vector. Integrating this over the loop would yield zero. "
] |
[
"How does the thermodynamic arrow of time imply the psychological arrow of time?"
] | [
false
] | Hawking, and others, have said that the second law of thermodynamics creates an arrow of time. And that the arrow of time we perceive is determined by this law. How is that the case? Why can't we use the reversibility of physical laws to send a message into the past? I know that everybody agrees we can't, but I don't see how this is implied from the second law of thermodynamics. As entropy increases, information decreases. Therefore there is more information in the past than in the future. This should mean that all the information from the future is also in the past. Wouldn't that make it easier to send a message back than forward? I'm missing something here... | [
"Making any sort of record, whether it's a memory or an external one like a note, is a thermodynamically irreversible process. That is, it involves an increase in entropy.",
"Therefore there is more information in the past than in the future.",
"There is more information ",
" in the past. The second law of th... | [
"The statement of the second law of thermodynamics (as applied to information theory) is that if you start with some piece of information (eg. a written message), then transmit that information through some method with some noise, the amount of information contained in that message will decrease over time. (Stated ... | [
"Whenever we do theoretical physics, we necessarily always discuss the physics of some closed system (it's just not possible to define most physical quantities in a meaningful way otherwise). The information we're talking about losing here is the information about the previous state of that system. So if we're goin... |
[
"Why is BICEP2 located at the South Pole?"
] | [
false
] | null | [
"This is addressed in the experiment's ",
"FAQ",
":",
"Why the South Pole?",
"Water vapor in the atmosphere absorbs microwaves, making detailed studies of the CMB impossible from most places on earth. The South Pole is near the middle of the Antarctic plateau, the driest environment on the planet. At an eff... | [
"Oh that one is a pretty simple answer. Not only is the south pole largely uninhabited which allows for less interference, but being in the south pole is actually the closest that we can get to space while being at ground level on earth.",
"I'm sure there are more reasons, but that is the gist of it."
] | [
"thank you!"
] |
[
"What happens to the body/brain when someone is under hypnosis? Is it a real state of mind, or is it power of influence?"
] | [
false
] | I have wondered about this since I was a university student. I've taken many psychology classes and different courses studying the human mind and hypnosis has always interested me but I also think it could be just the 'power of influence' or something similar. I have even tried to let myself be hypnotized on 2 separate occasions, but, I was told I might not be susceptible to hypnosis. So that has made me skeptical whenever I further read or observed someone being "hypnotized" for an intensive psychology session, or even on stage in a hypnotist/mentalist show. Is it real and what happens to the mind/body if someone can be successfully hypnotized? Edit spelling | [
"So...it's all fake then. If you're just following instructions then clearly you know you are in control and the hypnotist can't make you do anything."
] | [
"So...it's all fake then. If you're just following instructions then clearly you know you are in control and the hypnotist can't make you do anything."
] | [
"According to Derren Brown (see the JRE podcast with him), there are a mix of experiences. Some people just go along with it, some people manage to convince themselves to go along with it to the point they're certain they had no choice, and others seem convinced that it must have been real as they don't remember it... |
[
"Poincaré recurrence puzzles me greatly, could someone elucidate it?"
] | [
false
] | I have read some about the Poincaré recurrence theorem, and it left me very much confused, especially the examples given. If you have all particles that make up a gas in one corner of the room, in a matter of seconds the pressure will reach an equilibrium. Due to Poincaré recurrence, in an almost arbitrarily long time, the room will return to the state with all particles in one corner of the room. But how? Why would the particles do that? If the volume of the room is constant, and the amount of "stuff" in the room is constant, pressure should also be constant. I don't see where time comes in as a factor in this at all. Also, how would such an event look like? Would particles all of a sudden "decide" to not obey Boyle's law (among others), and spontaneously rush into the corner of the room? Would they be driven by some force against the pressure of the gas already in the corner? Could anyone clear it up for me? Sorry if I misinterpreted the whole concept, my understanding in this field is poor. | [
"Due to Poincaré recurrence, in an almost arbitrarily long time, the room will return to the state with all particles in one corner of the room.",
"But how?",
"Complete chance combined with a near-infinite amount of time. It's a little bit like the \"an infinite number of monkies on an infinite number of typew... | [
"Basically, the movement of particles in a gas is (under certain assumptions) entirely random. Each individual particle just cruises around doing his own thing until he hits someone else. The fact that gases expand to fill their containers is just a consequence of the fact that if there's \"a lot\" of gas in one ... | [
"Also: these particles could violate Boyle's law because Boyle's law is an approximation made under the assumption that particles are approximately uniformly distributed. "
] |
[
"Is there any evidence to show that people with blue eyes are more sensitive to light than those with brown eyes?"
] | [
false
] | Any scientific studies on the subject of light sensitivity and eye color? | [
"The eye sensitivity to light is dictated by the density of the rods/cones and by the density of macular pigment. Macular pigment provides \"sunglasses for your retina.\" It absorbs light before it can pass into the rods/cones. There are studies that show blue/green eyed persons have lower macular pigment than t... | [
"Are we asking if there is an optical sensitivity or an overall sensitivity such as to if one burns their skin more quickly or slowly?"
] | [
"i dont know, but i have green eyes and i cant go outside on a sunny day unless im wearing polarized lenses."
] |
[
"Why is enthalpy interchanged with heat?"
] | [
false
] | I.e heat of fusion = enthalpy of fusion | [
"In thermodynamics heat is defined as dQ = TdS, i.e., the temperature times the change in entropy of the system. Enthalpy is defined as dH = TdS + VdP, the heat plus the volume times the change in pressure, and it is often referred to as the heat function. If the system's pressure is constant, then dP = 0, so entha... | [
"Thanks, it's nice to see the difference mathematically!"
] | [
"Enthalpy and heat are both ways to describe energy. Enthalpy is a specific type of heat related to the breaking/formation of chemical bonds. The main difference between the two is that enthalpy is a state function. Heat and enthalpy can be equal in certain cases (e.g. reversible isobaric processes)."
] |
[
"Is it possible to cold weld the repelling ends of magnets together? If so, would their magnetic fields align?"
] | [
false
] | null | [
"It doesn't. A dipole magnet is already aligned. Like this: <<<<<<<<<<<",
"Now I break it: <<<<<< / <<<<<",
"And each of those is an identically aligned dipole magnet, without having to change the spin."
] | [
"Magnetic fields are due to the spin of electrons within the magnet. Placing two magnets together would not change the spin of the electrons, so the magnetic fields would not align.",
"However, over a long enough period of time, if you keep magnets near each other, the magnetic fields from one will affect the sp... | [
"But doesn't snapping a dipole magnet in half result in two dipole magnets? How does that change the spin of the electrons, if what you say is true?",
"Edit: Thanks for the responses! I think I understand."
] |
[
"i don't understand how fast quantum computers are?"
] | [
false
] | Quantum computers use qubits instead bits for computation. it says on wikipedia that a quantum computer with n qubits is equal to a classical computer that has 2 bits. one of the fastest quantum computers we have right now is a 512 qubits. but that means it can do 2 calculations or about 1.3E154. That is more than the number of atoms in our universe. How is that even possible, in the coming years it say we will have quantum computers with a million qubits. that is 2 calculations per second. That can not be possible. i don't understand or is that quantum computers are only that fast at solving problems like that for specific problems in math and science. | [
"No no no no. Quantum computers do not let you check an exponential number of states in a single operation. A quantum computer can be in a ",
" of an exponential number of states, but they cannot just tell you which of these states is correct in a single op. If this was true then BQP would trivially be a superset... | [
"No no no no. Quantum computers do not let you check an exponential number of states in a single operation. A quantum computer can be in a ",
" of an exponential number of states, but they cannot just tell you which of these states is correct in a single op. If this was true then BQP would trivially be a superset... | [
"it says on wikipedia that a quantum computer with n qubits is equal to a classical computer that has 2n bits.",
"This is a misreading of the article. Its not at all the case that they're in any way \"equal\". Its true that in general in order to ",
" n qubits, you would need 2",
" classical bits. This makes ... |
[
"What determines how many chromosomes a child will have if the parents do not have the same amount?"
] | [
false
] | [deleted] | [
"This happens and is quite interesting. As an example, think of a chromosome with 6 genes, ABCoDEF (the o is the centromere). You are aware that chromosomes can duplicate, but what happens if only the centromere is duplicated? In that case you'd get a situation like ",
"this",
". Now, when this cell begins to l... | [
"Starting back when nothing resembling humans existed, I'm curious as to how we came to have 23x2 chromosomes.",
"We know some details about this. Chimpanzees have 24x2 chromosomes, but humans have 23x2, even though our DNA is very similar overall. The missing chromosome is ",
"because of a telomere-telomere fu... | [
"It's likely, way back in the primordial ooze, that chromosomes used to be circular, resembling bacterial plasmids that we see today, and that reproduction was asexual rather than sexual. In this case, large mutations are passed on more easily. By the time linear chromosomes and sexual reproduction develop, single ... |
[
"Is fusion power still on track, 20 years later?"
] | [
false
] | In discussions like , this graph is often referenced, which shows the progress that's been made in fusion power, measured as triple product vs time: But the last point on that graph is around 1998, 20 years ago. When I , this decades-old graph is the only one I see. Is the triple product still doubling every 1.8 years? What would this graph look like if updated to today? | [
"I fear the graph is still up to date - no new records since them. JT-60U still has the highest triple product. ITER should beat it, but not before 2027. It should release 10 times more fusion power than necessary input power when run with DT plasma (2035+), a huge milestone. After that it is \"just\" making a viab... | [
"To add to this: DEMO is intended to be the first reactor to demonstrate that nuclear fusion reactors can operate comperially and it's planned for the 2040s or 2050s - that is if all goes well with ITER and then DEMO, which should operate in the range of 2 to 5 GW with a net gain of some 1 to 2 GW that can go into ... | [
"Why is it so expensive? What are those $100 billion getting spent on?",
"When you speak of \"costs to construct\", do you mean as in following a known design, or as in doing some research in the middle and perhaps testing out multiple approaches?"
] |
[
"Are toes really necessary or just an evolutionary hang-up?"
] | [
false
] | I realise that we use them for balance, but people can have toes amputated and regain full mobility. Lets face it, toes are gross, a pain in the ass to keep clean/manicured, and they don't seem that useful. Clearly early ancestors used them for climbing trees, grasping objects etc., but we just keep them in our shoes. This has puzzled me for while, do you think we could evolve sort of hinged end at the end of the foot, or get rid of them altogether? | [
"I realise that we use them for balance, but people can have toes amputated and regain full mobility",
"This is just not true. Sure they can ambulate -- which I am guessing you are calling mobility -- but without toes their foot structure is completely compromised compared to that of a normal healthy individual. ... | [
"Do you foresee a future where people with toes either die young or never get laid? Because that's the only way toes are getting \"evolved out.\"",
"Interestingly, there is a group in Africa, the Wadomo, where it is common to have ",
"two toes",
". "
] | [
"Can you explain the part where you say people who have toes amputated regain \"full mobility\"? I'm sure they will not be able to climb trees as fast as someone with toes. Or even run as fast (I'm just guessing though).",
"I personally don't think ANYTHING in our body is there without purpose. Even the frigging ... |
[
"Are insect cells smaller than the cells of larger mammals?"
] | [
false
] | Say you have a gnat or mosquito. Are the cells that make up the insect smaller in size compared to something like a human or rhino or are there just less cells that make up the insect? | [
"As a general rule, animals that are smaller tend to have lower cell counts, rather than having smaller cells. There's a size limit on how small things can be before they get too small to be useful.",
"Anyway, even within one organism there's a huge range in sizes.",
"So generally, fewer cells, rather than smal... | [
"To add to the first reply with an example. Between wax worms, mice, and humans, the size of the immune cells that protect these animals are quite similar even though the animals have drastically different sizes."
] | [
"Mostly, just less cells. Small animals lack the really long nerve cells you find in large animals (because the nerves don't go as far) but on the other hand may have other large cells. For example, ",
"some flies",
" have sperm cells that are 5.8 cm long. Yes, longer than the fly. Yes, that is crazy."
] |
[
"Do inertial reference frames really exist, are are they just a useful approximation? Related to orbits."
] | [
false
] | This might be a bit of a mess, since it's not something that I really know a lot about, other than accepting what I've been taught about the laws of physics being constant in all inertial reference frames. It may seem a little stream-of-consciousnessy. So discussions come up from time to time about Earth orbiting the Sun, and whether it really is objectively wrong to say that the Sun orbits the Earth. Even if you take the centre of mass instead of the surface, an argument that commonly comes up is that Earth is a non-inertial reference point, because we are accelerating around the Sun. Seems reasonable enough. But then my thoughts meander a little. The Sun experiences acceleration as it orbits the centre of the galaxy, and the galaxy experiences acceleration as it is drawn towards Andromeda, and their combined system experiences acceleration as they are drawn towards other galaxies in the Local Group, and the Local Group experiences acceleration as it is drawn towards other clusters, and so on and so forth. Doesn't this mean that no reference frame is inertial, because every possible point you can choose will always be accelerating relative to something? And how does the expansion of the universe play into things? So then I search and come across , where the top rated comments talks about reference frames that are inertial. And then my brain goes back to the beginning, thinking that if if we're only concerned with locally inertial frames, then if Earth is orbiting the Sun, does it not automatically follow that it's no less accurate to state that the Sun orbits Earth, if we're only only considering the two bodies as a system, and if we treat the centre of mass of Earth as our reference frame? Do we even need to change our reference frame if we move out to looking at the whole solar system, or the galaxy? Is it scientifically to keep using Earth as our reference frame, or is it just less computationally convenient? I'm becoming thoroughly confused, and less and less certain that I've even barely understood what I thought I knew. given gravitational attraction between all matter in the universe, is there really such a thing as a universally inertial reference frame? And in the context of the answer to that question, is it really 'wrong' to say that the Sun orbits Earth, or is it just a convention that makes things easier to conceptualise and calculate? | [
"So discussions come up from time to time about Earth orbiting the Sun, and whether it really is objectively wrong to say that the Sun orbits the Earth. Even if you take the centre of mass instead of the surface, an argument that commonly comes up is that Earth is a non-inertial reference point, because we are acce... | [
"You have to be very careful here. The Earth's orbit around the Sun is only locally inertial, but it is not inertial in a global sense. That is to say, there is not experiment you can do on the Earth, involving only things on the Earth, to see that you are accelerating around the Sun. But there certainty are experi... | [
"The apparent acceleration is due to the inertial motion of bodies along a \"geodesic\", which is the equivalent of a straight line in a curved spacetime. Proper acceleration, then, changes the geodesic along which the body travels.",
"Thanks a lot. That part especially makes a lot of sense."
] |
[
"How does the human brain keep time?"
] | [
false
] | I understand circadian rhythms, but I want to know how our brains keep time in a more immediate sense. For instance, how can I count the seconds at a fairly consistent pace? How do I a specific interval of time has passed? Digital computers rely on quartz clocks for timing calculations, so is there a similar feature in our brains? | [
"As far as I can tell from a literature search, I don't think the molecular mechanism underlying the perception of time is known at all. It is linked to different neurotransmitters (.e.g.), since a lot of psychoactive substances have dramatic effects on the perception of time. It is probably even harder to study in... | [
"There is current research on \"time cells\" in psychology labs, specifically Howard Eichenbaum at Boston University and Gyorgy Buzsaki at NYU. Basically, they found cells in the hippocampus (a major component in memory acquisition and consolidation) in the limbic system. Although their research doesn't specificall... | [
"a lot of psychoactive substances have dramatic effects on the perception of time",
"This. Psychedelics such as LSD and other substances that bind to the 5-HT2 receptors can have a dramatic effect on the perception of time.",
"It seems that time is counted by the entire brain and not by a single organ in the br... |
[
"What examples are there of evolutionary traits that originally helped individuals of a species, but were bad for the species as a whole?"
] | [
false
] | I was inspired to ask by u\atomfullerene 's comment in a recent thread. | [
"Now alcohol is slowing civilization rise. ",
"What does that even mean, how was it measured? ",
"Even better, alcohol had destroyed native americans.",
"What? I'm pretty sure that was genocide at the hands of an oppressive & expansionist government. Sure rampant alcoholism prevails on the reservations, bu... | [
"Now alcohol is slowing civilization rise. ",
"What does that even mean, how was it measured? ",
"Even better, alcohol had destroyed native americans.",
"What? I'm pretty sure that was genocide at the hands of an oppressive & expansionist government. Sure rampant alcoholism prevails on the reservations, bu... | [
"Humans evolved digestion of alcohol many thousands years ago. This allowed us to eat fermented fruit from underneath trees that have fallen down and still be able to run from a predator.",
"There is absolutely no evidence for this. Please cite a source"
] |
[
"With all the discussions about planets and their moons, I was wondering, Is it possible for a Super Earth, or even bigger than that but has the ability to support life, have a moon that can also support life?"
] | [
false
] | What I mean is that is it possible to have a very large life supporting planet, like our own, to have a moon that is also supporting life. I just think it would be awsome to be able to sit down and look up at night and see a moon that looks kind of like your own planet. | [
"Yes, in theory you could have two planet sized objects orbiting a common center of mass, both within the habitable zone. A much smaller object like Earth's moon would have difficulty supporting a stable atmosphere for a long period of time."
] | [
"Depends on the chemical makeup of the atmosphere you want. Heavier, colder gases are easy to retain, but typically less useful. A warm, light atmosphere like Earth would need a planet of similar size, but a cold, hydrocarbon atmosphere like that of Titan can exist on a much smaller body."
] | [
"Here is a size comparison of Europa to our moon",
"There is speculation that there may be life on Europa although I doubt it's anything large."
] |
[
"Do people change or are they merely re-conditioned?"
] | [
false
] | null | [
"I don't understand the difference between the two things you are describing.",
"Also, there is no nature/nurture debate, really. It's almost always a mix of both"
] | [
"I can see my vagueness. Let me try giving an example.",
"The proverb, \"Once a cheater, always a cheater\" or for example a drug addict or alcoholic or a career criminal.",
"If they cease cheating, using, drinking, and stealing, is there really a fundamental change or are they just the product of behavioural ... | [
"It seems like you are asking \"did they change as a person or did they just change their behavior\", that is, do they not ",
" to do X or did they just learn not to do it / that they shouldn't. Something like that? "
] |
[
"Suppose you had a very rigid ruler and you placed it along the equator at a very smooth site. How long would the ruler need to be before you would see space appear between the ruler and the ground because of the curvature of the Earth?"
] | [
false
] | And could it potentially expand into outer space if it was long enough? And if it was long enough and wide enough could we use it to escape Earth's atmosphere in space travel? | [
"Math.",
"You're doing it wrong."
] | [
"Math.",
"You're doing it wrong."
] | [
"Ok. Since we want a soccer ball of 71 cm fit underneath the ruler, we must take the radius of the earth and subtract .71 m from it. That gives us a 'vertical' (assuming for the problem that we think of the earth as its circular profile) length of 6378099.29 m. So treating that length as the 'opposite' side of a... |
[
"If I get half of my DNA from my mother and half from my father, why is my phenotype so different than either of theirs?"
] | [
false
] | [deleted] | [
"It's also possible that OP is adopted and doesn't know it. "
] | [
"Because each of your parents carries an unexpressed allele for those recessive traits, and you rolled a proverbial \"snake eyes\" when it came time to getting an eye color. It's the same concept behind ",
"Punnet Squares."
] | [
"Hey, improbable things happen! Somebody has to win the lottery, even when the odds are 20 million to one! And not ALL of your genetic traits are snake eyes, just a few of them that you can see. Remember that you can't make assumptions about genotype from looking at the phenotype."
] |
[
"Can we see Action Potentials as they happen?"
] | [
false
] | I can't seem to find anything on the subject. Has anyone every tried to observe them? Is it possible? | [
"We can indirectly observe the firing of neurons by measuring the voltage change caused by ion channels opening. ",
"This technique can be done fairly simply - it is called ",
"electrophysiology",
" - and it forms the foundation of modern neuroscience."
] | [
"I myself have never done any techniques to measure action potentials but have discussed them in paper discussions.",
"See this wiki article for more info:\n",
"http://en.wikipedia.org/wiki/Patch_clamp",
"Essentially you can measure electrical changes in the membrane using different techniques all with advant... | [
"Patch clamps can be used to measure the electrical signal. This is a well-established technique. ",
"There are fluorescent probes that can be used to observe the change in redox potential inside the cells, too. "
] |
[
"Why people don't get sunburnt in +50°C, but get in +30°C"
] | [
false
] | null | [
"Temperature has nothing to do with sunburn. I got horrifically sunburnt on the bottom of my chin when I was snow-skiing in sub-zero temperatures because I forgot to put sunscreen there.",
"You'll get just as burnt in 50 as you will in 30 - but someone else may not get as burnt, or may get more burnt. It depends ... | [
"Nope. He never uses that stuff and says that it's intended for metros only.",
"In Bahrain as mercenary he wore overall with top side off (tied it around waist) and in Latvia he just wore shorts. I thought it was because moisture! "
] | [
"Sunburn is not heat related. It's ultraviolet radiation damage. It has nothing to do with moisture at all - at times, the worst you can get sunburnt is if you're in a pool on a sunny day."
] |
[
"What is the difference between freezing specimens in a \"regular\" freezer vs a -80?"
] | [
false
] | My department is going to be moving, and I have a small number of samples I have processed for serum, homocistine, and antiphospholipids that are currently housed in borrowed freezer space, and I am extremely nervous (despite my clear labeling) they may get lost in the fray. So I was wondering whether taking them home and storing them in a "regular" freezer would cause them to degrade in any way? I can't imagine it would hurt serum much since it's thawed and refrozen for tests on fairly regularly, but I don't know much about the other two. TL/DR: Is -80 some how more frozen? | [
"not necessarily more frozen, but the difference between a house freezer and a -80 freezer is that, at -80, theres is much less enzymatic activity than there would be in a regular freezer (-20 ish?). Believe it or not, there is still activity in your samples even while frozen.\nThat said, certain samples might be o... | [
"Don't EVER use your home Freezer!\nHome freezers are \"frost free\" which means that although they are nominally at -20, they actually alternate freeze/thaw cycles every two or so hours to keep melting and eliminating the frost (which I'm sure you're familiar with from those -80's and lab freezers) that would othe... | [
"Two things, one, aliquot your samples, repeated freeze-thaws will cause all number of problems, from volume loss, to aggregation of proteins, loss of enzymatic activity, plus, every time you that you're risking microbial growth. ",
"As for your home freezer, that is \"frost-free\" which means that it warms and c... |
[
"There are many cases of species evolving to lose limbs for a snake-like bodyplan or losing other organs, is there any occasion where a species regains the use of a vestigial body part?"
] | [
false
] | null | [
"I don't know if it qualifies as a body part but primates did regain color vision, a trait that all early mammals had lost in favor of better night vision.",
"The commonly accepted theory is that it was an evolutionary trait the benefited primates in determining what fruits were ripe to eat as well as differentia... | [
"It’s actually super amazing. The red-green color differentiating opsin genes are right next to each other on the X chromosome (so females have two pairs and males only a single pair). This is thought to be because the red-sensing version gene was duplicated (in a human/chimp/gorilla ancestor) and then evolved into... | [
"Dewclaw. Wolves don’t have them (unless they are wolf dog hybrids). Probably wolves lost them as their ancestors did less climbing over jungle branches and more running through grass where it would add extra drag. Dogs have them again because they are useful in many things"
] |
[
"Does gravity have a speed?"
] | [
false
] | null | [
"Check out ",
"these past threads",
".",
"A star thousands of lightyears away from the galactic center of gravity would be orbiting around where the point was thousands of years earlier if gravity can only operate at the speed of light.",
"Keep in mind ",
"this thread",
" though, to answer that question... | [
"Is it possible that gravity operates in some way independent of c? Relativity says nothing can move relative to something else beyond c. But does this apply to an ",
"?",
"I've heard about certain quantum effects that seem to operate this way, perhaps gravity does as well?"
] | [
"The lack of aberration in gravity is explained by general relativity, so while it is entirely ",
" that a new mechanism exists, there isn't a present need to explore that possibility."
] |
[
"Is it possible mitochondria used to be parasites before becoming part of the cell?"
] | [
false
] | null | [
"Yes, it is known as the ",
"endosymbiosis theory",
". While there are some very compelling evidence, it is still an active subject of research."
] | [
"Chloroplasts, too, are considered possible endosymbionts. It's really a rather cool idea!"
] | [
"Unlikely that they were parasites, but mutualistic or commensalistic endosymbionts. The cell provided metabolism and/or photosynthetic capabilities to the host cell. This relationship eventually coevolved to the point where mitochondrial DNA has relocated into the host genome, rendering the mitochondria (possibly?... |
[
"What would a habitable tidally-locked planet be like?"
] | [
false
] | A tidally locked planet is a planet with the same side always facing the Sun, just like the Moon is tidally locked to us and we only ever see one side of it. This is something I've been interested in for a long time, so you can imagine my excitement when we actually in 2010. Gliese 581 g got a lot of press coverage for being in the center of its star's habitable zone, but articles really only mentioned in passing that it was tidally locked. I've tried to do a bit of research here and there on my own, but I haven't been able to find much reading on tidally locked planets (if you have any, let me know!) so my only option is to cross-apply what I already know and have learned on my own - which I can put any confidence in. If, for the sake of answering the question it's easier for to assume the tidally locked planet is exactly like Earth, feel free to do so. Here's what I'm confident about. From the perspective of a tidally locked planet, the sun doesn't move in the sky at all. Because of this, one half of the planet is always day, one side is always night, with a ring in between them that is always at twilight, effectively making times of day like noon and midnight geographic locations. Tidally locked planets also don't have any axial tilt, so there would be no perception of seasons throughout a year. The night side is always "winter" and the day side is always "summer", which a sort of Spring/Autumn in between where plants neither bloom or wilt, it's just a stagnant in-between of summer and winter without any of the transitionary events we associate with those seasons. I don't want to assume any more past that, so here are some of the things I don't know. How viable is life on a planet like this, given the dark side receives no light and the day side is interminably hot? Is this environment too stagnant to expedite evolution like we've had on Earth? What will the climate be like if cold-zones and hot-zones are constant? Would cold and warm fronts always coming from the same place and with the same intensity cause geographic areas to constantly have the same weather? Would the lingering heat of the atmosphere be enough to make any of the night-side habitable? Anything you know or could share your ideas on would be hugely appreciated, and if you have any creative questions about tidally locked planets that I've totally overlooked, be sure to ask. | [
"Tapio Schneider’s Vimeo page has a bunch of videos of simulations of a tidally locked earth like this one:",
"http://vimeo.com/19458103",
"Here's a paper: ",
"http://arxiv.org/abs/1001.5117/"
] | [
"My first intuition is that there would not be a water cycle as we know it, because this needs permanent bodies of water experiencing temperature differences. So, no weather, no wind, no rain. Climates exactly aligned with latitudes and only involving temperature.",
"In that case, the sunny side could be land or ... | [
"Note that if the planet has even a slightly eccentric orbit, the planet will still slowly rotate. This is because when the planet is at periapsis the tidal forces are stronger and its angular orbital speed is higher than when the planet is at apoapsis. The planet's rotation is locked to the angular orbital speed w... |
[
"How are satellites electronically grounded?"
] | [
false
] | null | [
"Everyone else is absolutely missing the point. Nearly all circuits in a satellite ",
" grounded, just not to the earth. The fact that you are not on earth makes grounding ",
" important, not less. Within ",
" in an space environment you can build up large charges between different circuits just based on t... | [
"They're not.",
"Electronics are likely using the frame itself as the common, which may be at a different potential than the surface of the earth, or not.",
"If there was no net charge on the ship to begin with, it won't \"build up charge\" because it's isolated in space. Where would the charge come from? I sup... | [
"I get what you're saying but the earth is huge, so it can obviously absorb a lot of charge.",
"Regarding where the charge would come from on a satellite, there is energy coming in all the time from solar radiation, that is where the satellite gets its power from. This is obviously then going to be converted to a... |
[
"What is up with the Gardasil vaccine? Is it safe, effective, etc?"
] | [
false
] | Not asking for individual experiences or medical advice. I don't want to hear what the company has to say about it nor the anti-vaccine crowd, thus why I came here to ask. I have noticed that news sources have reported that this vaccine has larger than usual adverse side effects (seizure, coma, death) and only treats 4 out of 100 strains of HPV. I was wondering what the current reliable reports are saying about its safety and effectiveness. For others: Obviously, this does not replace medical advice from your doctor! | [
"The main purpose of the vaccine is not to prevent HPV infection itself but to prevent the resultant increased risk of cervical cancer caused by HPV. HVP subtypes 16 and 18 (which are both covered by this vaccine) are the subtypes most commonly found to lead to cervical cancer."
] | [
"There is no reputable source that there are higher than usual incidents of adverse side effects of this vaccine as far as I am aware of presently."
] | [
"To begin: I am not a medical professional or a biochemist, as my flair indicates.",
"You should look at the National Institutes of Health ",
"page",
" on the HPV vaccine. This has information on side effects, etc. You can also see ",
"this link",
" from the CDC, plus the links it includes, to see repor... |
[
"Why does curing raw fish make it safe to eat in sushi? Alternatively, why can you not just do this with other meat like chicken?"
] | [
false
] | null | [
"Sushi (actually, sashimi - “sushi” is rice) isn’t cured. Sashimi is relatively safe because it’s high-grade fish, carefully processed. Even so, occasional parasite eggs slip through and cause health problems. Chicken, on the other hand, is processed in much larger-scale operations in which slaughterhouse bacteria ... | [
"Dont forget the chickens live highly stressed lives, which would normally cause them to succumb to diseases, except for the over administration of antibiotics."
] | [
"Dont forget the chickens live highly stressed lives, which would normally cause them to succumb to diseases, except for the over administration of antibiotics."
] |
[
"Could you pull a boat while on it?"
] | [
false
] | In a hypothetical situation, if you were on a wooden boat and tied some rope to one end and stood on the other side, jumped as high as you could while pulling the rope, would the boat move towards the way you pulled it? | [
"Yes. You and the tie point of the boat would move towards each other. If you were in a boat that weighs as much as you do and you pulled the rope one meter, you'd go backwards half a meter, and the boat would go forwards half a meter, not accounting for friction."
] | [
"And don't think about running to the other side and repeating the steps. As you run to the other end of the boat, the boat will be pulled back to the location it started at. You won't be able to achieve any net distance this way."
] | [
"I know we are talking about ideal systems and such like, but in reality the boat would experience more friction than the crewman and you would slowly progress."
] |
[
"Who has the advantage in a quiz where two people have to guess a number (e.g. an amount or a prize). The first guesser or the second?"
] | [
false
] | I am a radio host and sometimes conduct radio quizzes. As a tiebreaker between two contestants, I use a "guess how many"-question, like "How much money did the local government spend on traffic in 2015?" The first contestant gives an answer. The second one then answers. What is most fair? A: That the first one guess a number, and the second guess a number? B: The first one guess a number, and the second says higher og lower? My thinking is: In scenario B, number 2 has a 50/50 chance, but I am not sure if number 1 has the same 50/50 chance, because the success of his opponent is down to 50/50? Another question: Is the fairness affected by the nature of the question, i.e. the difference between a random number and an actual number that might be, but unlikely is known by one of the contestants? | [
"If both players are rational, then there should be no difference between your two modes of play (second player guesses or second player says higher/lower). Suppose player A says 50, and player B believes the answer is 60. It will always be strictly better for him to guess the minimal increment higher than the answ... | [
"One way to minimize a second player just choosing a number either 1 above or 1 below the first player is to incentivize guesses within some amount. So \"anything within 5 wins extra prize.\" This way if the first player guesses 50, and the second player thinks its 70, the second player would not just guess 51, but... | [
"Suppose player A says 50, and player B believes the answer is 60. It will always be strictly better for him to guess the minimal increment higher than the answer of A, say 51, rather than his actual guess. This way, if the true answer turns out to be 53, he would still win where this wouldn't have been the case ha... |
[
"If electromagnetic radiation all travels at the same speed, then how are we able to physically observe the visible spectrum of light from a supernova without simultaneously being harmed by the dangerous radiation emitted such as UV-rays, X-rays, and Gamma-rays?"
] | [
false
] | null | [
"Because the intensity of the light drops off as roughly 1/r",
". The light intensity is too weak to do serious damage, but you could still detect it."
] | [
"While ",
"/u/Mr_iLikeEverything",
"'s answer is technically correct, it's a bunch of jargon as far as I'm concerned. ",
"The simple explanation is that the radiation spreads out. Just imagine your torchlight. It starts from a 'point', ie a lightbulb, and spreads out to cast a wide beam. If you place a piece ... | [
"I actually just did some searching and I apparently exaggerated: ",
"there are a handful",
" of stars that have been resolved beyond a pixel (but never as more than a fuzzy ball).",
"It shouldn't be a big surprise, though! Most stars are about 1 million kilometers across or less. The biggest stars aren't muc... |
[
"Is the big red spot stationary?"
] | [
false
] | Is the big red spot a relative stationary storm? Or does it move across jupiter like a hurricane on earth? Do we know what has kept it going for long? And what would take for a storm like that to happen on earth? One that rages for years and doesnt move from one spot too much? | [
"It's a tough to define \"stationary\" when the whole planet is a big gas ball. Three different coordinate systems are commonly used for Jupiter: System I is based on the rotation rate of stuff near the equator, System II is based on the rotation rate of features near the poles, and System III is based on the plan... | [
"Jupiter is a fluid planet, and nothing on it is stationary",
"Just to add to this: The equator of Jupiter rotates once every 9h50m. Mid-latitudes rotate once every 9h55m. You can do that when you're not a solid."
] | [
"The current available theories as to why this high-powered anticyclone continues to rage for hundreds of years is pretty simple.",
"There is no land to create friction in order to slow down the storm.",
"Just like on Earth, the Pacific storms tend to be stronger than Atlantic storms because there is larger ex... |
[
"The evolution of birdsong?"
] | [
false
] | null | [
"Things created through sexual selection (which I'm speculating created most birdsong) generally gain complexity and ornamentation as they involve, so just imagine a less interesting version of what you heard today. How much less interesting? Well, that's where it gets unknowable."
] | [
"Well it depends really. There is a period where birds undergo a process called crystallization. Basically it's a point in maturity where they begin fine tuning their song as they mature. Now studies have shown birds do not inherit song from their parents but rater the frequency and rate they sing the song. So bird... | [
"A good home for this question would be ",
"/r/AskScienceDiscussion",
"."
] |
[
"Is a lightning bolt heat making light or is it light?"
] | [
false
] | [deleted] | [
"it is electricity making heat AND light..."
] | [
"First you'd have to explain in detail what \"Electricity\" really is. It can't be done, since reference books disagree over the correct definition of the word \"Electricity.\" So just avoid it. If you mean \"electrical energy,\" then say electrical energy. Same with flows of charge, etc.",
"Lightning is a... | [
"the light comes from heat as the electricity heats the air to ~50,000 degrees. ",
"http://en.wikipedia.org/wiki/Lightning"
] |
[
"Is there any/could there be any two elements that could undergo both synthesis and decomposition in the same environment?"
] | [
false
] | I'm asking if you could have elements X and Y you could have both X + Y --> XY and XY --> X + Y but not have to change the surroundings, and would therefore spontaneously switch between XY and X + Y | [
"In principle, literally every chemical reaction does this. Every reaction is reversible, and will follow the same pathway in both directions according to what chemists call the principle of microscopic reversibility. A great many reactions so heavily favor one side that the rate of the opposite reaction is negli... | [
"You got your answer, OP, not much to add. Maybe just keep in mind that ",
" or ",
" are only valid at the molecular level, but at the level of a solution, the two occur. Not at the same molecules at the same time, of course, but one X will undergo successively the two reactions, all the time.",
"XY is not t... | [
"Literally all reactions are basically in an equilibrium, however skewed towards one side or not. ",
"Given enough pressure, heat or proper catalysts, I would dare say that all reactions are reversible, because of the fact that all reactions are basically equilibriums. ",
"Although we usually classify chemica... |
[
"A physics puzzle"
] | [
false
] | On the floor of an elevator/lift are a blob of mercury and a lit candle in a holder. The cable snaps. What happens? (Assuming the the lift shaft to be very long or infinite.) | [
"Blob of mercury: The blob of mercury will, to minimize surface energy, become a sphere. The motion from changing shape will impart momentum to the sphere, and it will drift upwards from the floor.",
"Candle: The flame will die. Since the air is accelerating with the candle, convection cannot occur (wherein hot, ... | [
"The elevator is in freefall. It's impossible for anything inside to distinguish between that and zero gravity. Anything that happens in zero gravity will also happen here.",
"No natural convection will happen. There's no direction that air can rise.",
"There may still be enough diffusion for some oxygen to rea... | [
"Candle in space",
"A candle is capable of burning in free fall, but the sudden shift from stable to plummeting might make enough turbulence in the air to put out the significantly weaker flame anyway."
] |
[
"Does the gravity of everything have an infinite range?"
] | [
false
] | This may seem like a dumb question but I'll go for it. I was taught a while ago that gravity is kind of like dropping a rock on a trampoline and creating a curvature in space (with the trampoline net being space). So, if I place a black hole in the middle of the universe, is the fabric of space effected on the edges of the universe even if it is unnoticeable/incredibly minuscule? EDIT: Okay what if I put a Hydrogen atom in an empty universe? Does it still have an infinite range? | [
"In theory, yes. Gravity has an infinite range. However, it also takes some time to propagate - information about local changes in the gravitational field will propagate at the speed of light. So if a supernova goes off and creates a black hole, we won't feel the gravitational disturbance until we see the light fro... | [
"Lots of mass accelerating really hard makes gravitational waves. While the gravity of a star and similarly massed black hole will be practically indistinguishable, there will be a blip associated with the transition."
] | [
"if a supernova goes off and creates a black hole, we won't feel the gravitational disturbance until we see the light from the supernova. ",
"Would there be any difference in the gravitational effect? Doesn't the supernova star have the same or more mass than the black hole?"
] |
[
"If you are trapped underwater and need to make it to a breathing hole, what should you do (to survive) - swim slowly and limit CO2 production? Or swim quickly and reach the hole faster?"
] | [
false
] | null | [
"As a freediver, the second one you said. EDIT: the most efficient way to swim is ",
"this one",
", but can be psychologically challanging to wait in such a situation. But just look at the movement. The hands are kept near the body, and all movements are slow and gentle, to reduce turbulence."
] | [
"Well, disregarding any physiological effects, drag is proportional to the square of the velocity, so your required energy expenditure will be exponential with an increase in velocity. So super fast would not be good. That being said, there will be some optimum point as going super slow will most definitely not b... | [
"Even the weakest exponential growth rate will eventually overtake a function raised to some constant exponent (2, in the case of quadratic functions). In the long run, exponential functions break systems.",
"Like, for example, financial systems."
] |
[
"Whats the difference between moving a muscle through electrical stimulation and moving a muscle normally?"
] | [
false
] | I just bought a electrotherapy device about a week ago and am very curious about some of the strange things I see when I crank it up. Basically, does a stimulated muscle do all the normal stuff like burn up ATP? What differences are there if any? Fun follow up: Could we wire someone up for a life sized game of QWOP? | [
"When you decide to extend your arm, you send an impulse down your nerves to an effector nerve (sometimes called motor nerves), this then stimulates the muscle to contract, extending your arm. ",
"This electrical device is also sending an impulse down these same nerves stimulating a response.",
"The muscle itse... | [
"given my previous experience with ethics committee I do not see such an experiment being granted approval",
"What would they think about an experiment where you lock a committee inside of a burning building?",
"Jokes aside, good info!",
"What would happen if a weight lifter kept lifting until all the ATP was... | [
"So ATP is made by aerobic or anaerobic respiration. In the presence of oxygen glucose is converted to a net gain of 36 ATP. For anaerobic or no oxygen, it is made in 4 ATP and acid builds up giving an oxygen debt that must be repaid.",
"For us to run out of ATP we must run out of Glucose and also fats as one eve... |
[
"If a peice of metal was lodged in a brain, could neurons use it as a \"wire\" for permanent communication?"
] | [
false
] | Has this ever been observed or experimented with? | [
"Not quite true actually. The vast majority of neurons communicate through chemical means, where neurotransmitters in various forms trigger postsynaptic events.",
"However, there are ",
"electrical synapses",
" as well. Granted, electrical synapses are not as common as chemical synapses, but they exist and ar... | [
"That's fascinating. I've never heard of electrical synapses before."
] | [
"How do they connect probes into the brain to read neuronal signals? I've read something about scientists interfacing a rat brain to an integrated circuit before."
] |
[
"Does the order of different insulators affect their total insulating capability?"
] | [
false
] | Real world example: I have a sheet, a comforter, and a random fuzzy blanket. Does the order of the blankets matter to keeping me warm? My first guess is "theoretically, no, but with real-world conditions: ..." | [
"In a super crazy simple world where every variable was controlled other than energy in + energy out, then no, it would not matter, same overall result. In the real world, it matters a lot. Try putting your down jacket over your raincoat on a wet day. There are 100s of examples like this one where order and othe... | [
"Relative weights would factor in for some blankets, if a lightweight fabric relies on relatively large air pockets for an insulating effect, a denser blanket on top would compress those pockets and make them less insulating. "
] | [
"Put the most easily compressed layer on top. That way the total thickness including trapped air is more, which is warmer. Some layers might be better at removing sweat, or they're easier to wash. Those reasons justify sheet below blanket below comforter."
] |
[
"Why do humans enjoy carbonation?"
] | [
false
] | null | [
"I hate them"
] | [
"The bubbles that 'sting' your mouth makes your brain release dopamine. Dopamine is the chemical that makes you feel happy and can lead to addiction to multiple things such as food, drink, or drugs.\nEdit: Grammar."
] | [
"i agree, but then why carbonate? sodas would still be sweet if uncarbonated ..and what about beer? "
] |
[
"Has anything ever broken the speed of sound underwater? What would happen / does happen?"
] | [
false
] | The speed of sound in water is around 5 times the speed of sound in air, or around 1500 m/s. | [
"The article says the missile can go 230 mph. The ",
"speed of sound in water",
" is around 3,347 mph. ",
"Cavitation",
" is the result of water vaporizing in the low pressure regions resulting from ",
"Bernoulli's Principle",
". We have a hard time getting things to 1497 m/s in air, let alone water.... | [
"You must not have read the second article which says \"He succeeded in making a super-cavitation-projectile, which could be used to detonate underwater mines in the future, accelerate in water to a record speed of 5400 km/h: \"Unfortunately I am not allowed to explain very much, because a lot of what we are worki... | [
"Sorry, I saw a continuous stream of blue and thought there was only one link. It's good practice to use line breaks.",
"The 5400 km/h claim seems suspicious in comparison to the other values, as well as when compared to speeds of projectiles fired through the air. I wonder if it should be 540 km/h. I'm not fi... |
[
"Why do worms come out of the ground onto the footpath when it's raining?"
] | [
false
] | Whenever it rains, the footpaths in my neighbourhood are covered with of worms. Why do they come out of the dirt to lay on these hard wet surfaces? | [
"Worms actually breathe through their skin and they have to stay wet or moist so oxygen can be absorbed. When it rains and the normally dry surfaces are covered in water, it gives them opportunity to go where they otherwise can't. "
] | [
"Can you, likewise, source that fact? I don't know who to believe!!"
] | [
"Can you, likewise, source that fact? I don't know who to believe!!"
] |
[
"I'm making a scientific Christmas present concerning DNA and I was hoping somebody could help me?"
] | [
false
] | null | [
"You will want the DNA coding strand to match the mRNA strand: the 5'-3' strand of DNA will have the same sequence as your mRNA strand. In real life this can sometimes vary: some genes are transcribed from the coding strand (5'-3') rather than the template strand(3'-5'), but for your project no worries! Also the st... | [
"I'll send you a picture when it's done! :D",
"I got all the materials yesterday. I got thin popsicle sticks, gold (colored) wire, and some hot glue. I'm breaking the popsicle sticks in half and using the halves to make base pairs. So one stick can make a TA and a CG. Right now I'm color coding, and when I have e... | [
"Thank you :)",
"So about the methionine one, what will I do for the beginning of Christmas? I've been using \"-stop-start-\" as the space. Should I just smush it all together to MERRYCHRISTMAS?"
] |
[
"Why don't Christmas lights get dimmer as you go down the string? Does each light not suck up some of the energy?"
] | [
false
] | null | [
"For series lights\nThe same amount of current goes through each light, meaning each light uses the same amount of energy.\nAs you go down the strand energy decreases, but at a constant amount for each light (assuming same resistance).",
"For parallel lights\nAll the lights are wired independently and there is no... | [
"The pressure is the same at each spout",
"The pressure ",
"."
] | [
"Because that’s not how electric potential works. ",
"Think of the wire like a pipe of water. Each light is a spout along the pipe. The pressure is the same at each spout, rather than one end having all the pressure and the other end having none",
"Edit: in this analogy the pipe is horizontal. With a vertical p... |
[
"Why does the US launch rockets in Alaska?"
] | [
false
] | I get that they could launch over the Pacific so they don't fly over people, but doesn't the equator have an easier time due to the faster rotation of earth? Is it for longitudinal orbits? Thanks. | [
"Launching from the equator is mostly beneficial for equatorial orbits. In the case of polar (ie orbits that go over the north and south pole) or sun-synchronous orbits you do not get much advantage from lunching at low latitudes. ",
"It can also sometime be interesting to launch sounding rockets at high latitude... | [
"The local gravity DOES change a little based on where you are, due to the oblateness of the earth (the poles are squished together a tad bit). The distance you have to travel to get off the earth also changes due to the oblateness. But the overall local gravity difference is only about 0.35%. That's 100 pounds ver... | [
"There's no difference in escape velocity depending on where you launch from, but there is a different in initial kinetic energy.",
"From ",
"/u/DaKing97",
"'s ",
"second source",
":",
"\"The energy per kg [launched into LEO] at the equator is 3.25 x 107 J/kg compared to 3.26 x 107 J/kg at the North Pol... |
[
"How are we able to imitate pitch so well?"
] | [
false
] | If someone were to sing a song right now, most people could imitate the pitch (the notes) very easily. However, if I was asked to do the same on piano I would have trouble and fumble while doing so (despite years of playing). Is the ability to match natural pitch in the voice solely due to extensive practice by talking and if so by what age do people get good at this skill? | [
"The imitation of pitch in infants",
" suggests that babies from 3 to 6 months can vocally match pitches that they hear. This is before speech has fully developed, which suggests that this skill is either innate or develops even earlier in the child's life.",
"As for piano playing, unless you started before pre... | [
"An additional difference between piano and voice: when you are singing, you get instantaneous feedback on the pitch you are producing and you can correct that pitch almost instantaneously as well. Your voice is a little flat? Increase the pitch until everything sounds right.",
"You can sorta do this on piano, bu... | [
"This is before the onset of language, which suggests that this skill is either innate or develops even earlier in the child's life.",
"I would be careful with this statement. Certainly 3-6 months is before the onset of speech, and probably before the onset of understanding of speech, but \"language\" writ large... |
[
"What is the eukaryotic revolution"
] | [
false
] | null | [
"This sounds like a high school assignment...and assuming you're in high school, your comment history..."
] | [
"You know these accounts are free, right? You could just make another one right now. You don't even need an email address."
] | [
"Lol im in bio150 also. Eu cells are far more compartmentalized, which i stated earlier allow for specialization. Unlike Pro, that are just one giant compartment."
] |
[
"Why does the half life not correspond with the time you can feel the effects of a drug?"
] | [
false
] | Caffeine half life: 6 hours, but you can only feel the effects for about two hours. Although you can feel some physical effects(anxiety, tremors, not able to sleep) you cannot feel the mental effects anymore. Same thing with Benzos, like Valium, with a half life of 200 hours, but you can only feel the effects a couple of hours. What causes this? does your body start to increase neurotransmitters that do the opposite effect of a drug? Also, why are some drugs like alcohol eliminated at a constant rate regardless of the dose(one drink per hour) but almost all other drugs are eliminated according to their half life, which Im assuming means that even with a larger dose, more is eliminated, unlike alcohol. | [
"Actually, alcohol is indeed eliminated faster when blood concentration is higher, because of higher concentration of alcohol eliminated in urine/breath and metabolized.",
"But alcohol is eliminated via pseudo-zeroth order kinetics - the rate of elimination is the same for most blood alcohol concentrations. It's ... | [
"An extreme example: the case of nicotine's effects on heart rate. A peripheral injection of nicotine is given. It takes a few minutes for most of this nicotine to even get into circulation, let alone be metabolized. The maximal effect of nicotine to stimulate heart rate increase occurs before the peak blood concen... | [
"There is a whole mess of processes going on that control response to a drug or compound put into our system. Biological half-life is only one of many factors contributing. ",
"Like you allude to, we have to consider a compound's biological half-life, receptors being up- or downregulated in response and tolerance... |
[
"Can someone validate/bust the scientific claims in this post? [X-post r/trees]"
] | [
false
] | Here's the link Thanks | [
"Mostly true, often oversimplified. 220Kps is only correct for a very specific frame of reference, saying that microbial DNA which you got from your mother ",
" is 'not you' is somewhat facile, 'empty space' as used here is not necessarily a meaningful concept in quantum physics, and the physical phenomenon resp... | [
"All true (with some assumed definitions and limits in some cases, but perfectly reasonably assumptions)."
] | [
"2500 is right, but I think what the 90% microbial DNA statement means is that you do have a lot of eukaryotic 'you' cells, but you also carry a vast amount of bacteria in your gut and on your skin that you rely upon for a great many things, so in that respect the statement is true. "
] |
[
"Why are avocados and kiwis green on the inside?"
] | [
false
] | Most fruits are either the same colour on the outside as the inside or a duller, whitish colour on the inside. In my mind I associate green parts of plants with photosynthesis and there isn't any of that going on inside of an avocado | [
"I can at least answer the chemistry part of the question. The fact that you are associating the color with compounds related to photosynthesis is spot on. The green color in the skin and the first layers of the flesh comes from chlorophylls and carotenoids. (",
"source",
") For the same reason avocado oil happ... | [
"This is something I've always been curious about as well, so you got me to look it up finally. I've always suspected that the chloroplasts in avocado had something to do with the production of the fats that make avocados so delicious. Chloroplasts are involved in of the physiology of plants beyond just photosynthe... | [
"Pigments in avocado tissue and oil.",
"Ashton OB1, Wong M, McGhie TK, Vather R, Wang Y, Requejo-Jackman C, Ramankutty P, Woolf AB.",
"Abstract\nPigments are important contributors to the appearance and healthful properties of both avocado fruits and the oils extracted from these fruits. This study determined c... |
[
"If earthquakes happen along faults why do we define the center as a point (epicenter) instead of a line (epiline?)"
] | [
false
] | Is there a point on the fault where the earthquake 'happened more'? I understand how they determine the epicenter if that matters... With the whole find three places that detected the seismic activity and determine how far away it was from each one.(or at least that's how they taught it back in high school) | [
"The epicentre is the point above the focus, which is where the fault ",
" to rupture. The rupture itself will travel up and/or down the fault to a certain degree."
] | [
"I don't think it's that cut and dried. There are many factors to take into account when it comes to earthquake damage - more damage was caused by fire in the 1906 San Francisco earthquake than the quake itself. Other factors like the type of ground have to be taken into account as well."
] | [
"I must confess ignorance."
] |
[
"Can you get a stroke from breaking your neck?"
] | [
false
] | A friend showed me article (which is probably BS) about a guy who had a stroke after breaking his neck that turned him gay. Leaving aside for a minute whether the story is true, is it even possible for a stroke to result from someone breaking their neck? | [
"My uninformed opinion is:",
"A stroke is essentially a blood clot in the brain and therefore you could assume that an injury would give a higher chance of blood clotting, so it's plausible.",
"Strokes are known to affect brain function, so if the stroke affected a part of his brain that controlled sexual desir... | [
"I can provide a pretty good rationalization of what PROBABLY took place here. This person most likely had a some sort of pretty significant trauma that cause him to break his neck, or as they call it in emergency medicine Mechanism of Injury. Given the the mechanism was significant enough to cause a broken neck, h... | [
"http://www.bupa.co.uk/individuals/health-information/directory/i/ischaemic-stroke",
"There is a kind of stroke than can happen if damage occurs to those large arteries in the neck because the brain won't get enough blood. Perhaps a broken neck could involve such damage. ",
"The injury might also be associated ... |
[
"When a Li-ion battery is first manufactured, is it already charged? If so, how much and why that amount?"
] | [
false
] | [deleted] | [
"It actually depends on the chemical composition of cathode and anode during production of the battery (the plus and minus of the battery). I don't know what is common practice in Industry. Discharging / charging is nothing more than moving Lithium from the cathode to the anode or back by a chemical reaction.",
"... | [
"IIRC the batteries are actually charged/discharged in the factory for quality control - different manufacturers, capacities, testing practices result in varying degrees of remaining charge. Since these batteries are actually extremely efficient, they do not discharge much while in the packaging, hence a phone with... | [
"The main reason that this used to be suggested, and not so much anymore, was due to how Nickel-Cadmium (and other Nickel based) batteries worked. If you partially charged or discharged them it would significantly decrease the life-span of the battery through the 'memory effect.' Lithium-Ion batteries don't suffer ... |
[
"What is the maximum temperature you can achieve simply by focusing sunlight using mirrors and lenses?"
] | [
false
] | My friend claims that since the temperature of the Sun's surface is around 6000 degrees Celsius, then that is also the maximum temperature you can conceivably achieve on Earth by focusing the Sun's energy on a single spot, using any number of mirrors and lenses of any kind. This seems wrong to me. Surely the temperature of the Sun is irrelevant, right? P.S: We've got a beer riding on this. | [
"I'm just going to leave ",
"this",
" here."
] | [
"Your friend is correct. To heat an object more than 6000 C means you are using a cooler object to heat up a hotter one. It's a direct violation of the 2nd law of thermodynamics."
] | [
"There is an extremely fundamental problem with most of the arguments saying it is easy to surpass 6000 K, and it's ",
" just that they violate the Second Law of Thermodynamics. (Reminder: Clausius's formulation of the Second Law is \"No process is possible whose sole result is the transfer of heat from a body of... |
[
"Why did the Earth originally have a super-continent, Pangea?"
] | [
false
] | So I get that there was a single giant landmass that spread apart due to tectonic activity, but WHY was it a single landmass to begin with? Is there a force that makes this happen or could it just as likely have begun with multiple continents from the get-go? | [
"Pangea was only the latest of a series of supercontinents that have been forming every few hundred million years for the last few billion years. We still don't totally understand some of the cyclical processes that form these supercontinents, but the short version is that ocean basins tend to keep spreading and co... | [
"This is called the Wilson Super Cycle and it happens every 200 million years or so. No one really knows why this happens though.",
"As a fun factoid, plate tectonics has only been an accepted scientific theory for less than a hundred years, so they haven't been working on it long."
] | [
"A quick Google search tells me that pangea was formed by older continents and land masses joining together.",
"So pangea wasn't the original continent.",
"It is believed that several mega continents have formed and broken apart during earth's history with Pangea being the most recent. "
] |
[
"How dangerous are the Chinese fake eggs?"
] | [
false
] | For those who don't know what I'm talking about, . Out of curiosity, how dangerous would it be to eat those? (I heard it could lead to dementia but without much scientific explanation) The real reason behind this question: I have this great idea for a prank - and it involves making a fake egg and then replacing the yolk with a fake eye. When people crack it open, BOOM! an eye in an egg. I have absolutely no intention of feeding these to anyone. So, in light of that, here's a couple follow up questions: Anyone knows what chemicals they use and whether or not they easy to get legally and safe to handle? Other than the previous question, is there any reason not to do this. EDIT: Fixed link format | [
"This could be relevant:\n",
"http://www.hoax-slayer.com/fake-eggs-china.shtml"
] | [
"Just an FYI, you've got your reddit linking backwards. You typed:",
"[http://www.youtube.com/watch?v=0US7JEfhsrA](check this out)\n",
"when what you should type to get your desired effect is",
"[check this out](http://www.youtube.com/watch?v=0US7JEfhsrA)\n",
"which yields",
"check this out"
] | [
"Well, the ",
"recipe here",
" lists the following items as ingredients: Sodium Alginate, Gelatin, Baifan, Sodium Benzoate, Lactone, Carboxymethyl Cellulose, Calcium Carbide, Lysine, Food Coloring, Calcium Chloride--this is for the white and yolk.",
"The shell is made of paraffin wax and Gypsum powder.",
"A... |
[
"If we could look far enough into the universe, will light be red-shifted to the point of having an infinitely long wavelength?"
] | [
false
] | Supposedly if we move far enough away from something, the expansion of the universe means that even if we travel at the speed of light we can never reach that thing again. So does that mean the light on the cosmic horizon would be red-shifted to be an infinitely long wavelength? | [
"The highest redshift photons we can observe are those from the cosmic microwave background. Higher redshift photons cannot be observed because before the last scattering event -- when the CMB photons were able to freely propagate -- the universe was \"opaque\" to photons, i.e. photons were not able to travel witho... | [
"I have a terrible problem with making things accessible, so if I fail miserably, feel free to let me know.",
"The CMB is different from stars and galaxies. Whereas stars and galaxies are essentially \"point source\" objects that emit light from a particular part of space, the CMB is ",
" in space. This means t... | [
"are we saying that at any one moment in time, the CMB we see IS the current cosmic horizon",
"It's wrong to call the CMB the cosmic horizon. They're two different things. The CMB is isotropic radiation; it's everywhere in space. The cosmic horizon is a horizon associated with objects which have ever been in caus... |
[
"A sincere request"
] | [
false
] | null | [
"Thanks for the feedback! I agree that this is a problem, especially with our status as a default subreddit. We'll be addressing this in our next meta-post. I've removed this one, because we try to limit the number of meta-posts (posts about AskScience itself)."
] | [
"Unfortunately this thread was deleted before I got here - I have a feeling this has to do with his objection with my involvement in multiple threads today. He repeatedly questioned my science, even going through my comment history to drop his own comment replies, culminating in ",
"this gem here",
".",
"I'd ... | [
"Here's the text",
"Please please stick to your own area of expertise while answering questions or at best, areas where you are a 101% confident you won't slip-up. People come here to genuinely clear up their doubts, and it doesn't help giving them patently false answers."
] |
[
"is space-time discrete?"
] | [
false
] | This based on my understanding of the Planck second as the required for a change in the position of a photon. does this also mean there is minimum distance traveled per Planck second? Does this not mean space time is discrete and not continuous? | [
"The answer is we don't know. All theories that deal with this are in the super spectulative realm. Quantum loop gravity, for instance, deals explicitly with discrete space-times but we have no strong tests of this in the foreseeable future (for what can be done, see the reply comments). Historically, discrete spac... | [
"This paper",
" discusses a few possible schemes by which one might test whether or not spacetime is discrete. Note that this is written for experts, but I thought I would mention it here just so that everyone is aware that there are some ideas out there of how this could be tested in the not so distant future."... | [
"Okay worth clarifying here: there are no ways (in the near future) of testing discreteness in a way that discreteness could fail. If such an experiment failed to find discreteness it will only tell us that, if space-time is discrete, it is discrete at smaller scales than we have measured. So it's a nice link but m... |
[
"Would it be possible to oxidise Gold using Chlorine Trifluoride ?"
] | [
false
] | Just asking, to be honest. I'm not really a chemistry guy but things that go ''Boom'' are always interesting, and Chlorine Trifluoride being a super-dangerous chemical that can set fire to Asbestos, would it be possible to oxidise Gold using it ? Ib haven't found a single article, paper or anything on the matter. I'd really like to see if Gold could potientially oxidise. Thanks ! | [
"No, it's a verb used to say an atom \"lost\" or gave his electrons to another atom. "
] | [
"I don't know about chlorine trifluoride in particular, but for your general question: yes, gold can be oxidised. You can \"dissolve\" (it's not really dissolving but reacting) gold in ",
"aqua regia",
" (\"royal water\"), where it forms [AuCl",
"]",
". Here gold has a formal +3 charge. Funnily enough aqua ... | [
"The term \"oxidation\" is mostly an archaic term from the now proven false assumption that such reactions would require oxygen. We eventually discovered the underlying mechanics though, but we didn't update the terminology."
] |
[
"Are there any planets that an average human, theoretically, could lift on Earth?"
] | [
false
] | null | [
"No. Objects that small are not classified as planets"
] | [
"By small you mean small in mass right? So even a planet made up of pure gas, it would be too heavy (with respect to gravity on Earth)?"
] | [
"See ",
"here"
] |
[
"Do antibodies get constantly gobbled up by the immune system or does it only get gobbled it up if it binds to something? if so why."
] | [
false
] | null | [
"Okay so there are many kind of antibodies - IgG, IgM, IgA and IgE. ",
"IgA are only functional outside of the body (in your intestines and in your respiratory tract). IgE are only functional once bound to a very specific type of cell - they cause allergies. IgG and IgM, on the other hand, have many purposes. Whi... | [
"Interesting thank you"
] | [
"Antibodies are made by the immune system, specifically B-cells. They are used as targeting proteins so that your body can respond to diseases/pathogens. If they are expressed on the surface of the B-cell, then when they find and bind to something 'foreign', they can then cause the B-cell to proliferate (divide and... |
[
"How high (or at what speed) would a person have to fall from to \"burn up\" in the atmosphere?"
] | [
false
] | Got into a bar argument and the person was of the opinion that the shuttle only gets hot because it comes in at an angle and that a person could never free fall to the earth at a high enough rate of speed to burn up. | [
"The \"burning\" (not really burning at all) is indeed completely due to the speed at which the shuttle enters the atmosphere. Angle isn't really the reason, it's just that the shuttle is going really fast while in orbit and the easiest way to get it back is to alter the angle just slightly which results in it comi... | [
"I don't have the know-how to do the maths, however I think that you could work it out using the resources linked in ",
"this \"xkcd what-if\" entry",
". "
] | [
"This is a very loaded question...",
"The \"burn up\" is a result of speed, obviously. But height is not the most significant factor here. The important factor is speed relative to the terminal velocity. For example:",
"One problem with sustained supersonic flight is the generation of heat in flight. At high sp... |
[
"would the mass of a helium balloon be positive or negative and is there such a negative mass"
] | [
false
] | [deleted] | [
"The mass of a helium balloon is positive. The weight is negative. There might be such a thing as negative mass, but we haven't encountered such a thing yet."
] | [
"That depends on your definition of weight. I though about adding a disclaimer for this, but decided not to. Pitty.",
"Anyway, you know how you are \"weightless\" in water? Or a sub is \"weightless\"? That's the definition I used - i.e. taking into account the buoyancy. My weight is how much force I exert on thin... | [
"That depends on your definition of weight. I though about adding a disclaimer for this, but decided not to. Pitty.",
"Anyway, you know how you are \"weightless\" in water? Or a sub is \"weightless\"? That's the definition I used - i.e. taking into account the buoyancy. My weight is how much force I exert on thin... |
[
"How long do landmines remain active?"
] | [
false
] | How long does it take for the explosives to become inert? Does the process by which the mines become unable to explode speed or slow depending on climate and soil composition? | [
"According to the wikipedia article for ",
"Anti-personnel mines",
" the most common primer/detonator charge used is an explosive called ",
"RDX",
" which seems to be able to maintain its capacity to explode for a very long time (extremely stable). ",
"Commonly used things for main charge seem to be TNT, ... | [
"Depends on when and who manufactured it. Many of them now have features where they will self destruct after a preset time. Many are now made of plastic and are extremely difficult to detect - even by those who laid them. Not much point in denying the enemy use of territory if you can't use it yourself. Older mines... | [
"Every now and then here in Virginia they find ordinance from the Civil War that is still dangerous, although landmines weren't really invented yet."
] |
[
"What size would an object orbiting the Moon need to be to be visible with the naked eye from Earth?"
] | [
false
] | I'd assume it would be a range of sizes depending on what it was made from, man-made or naturally occurring, and how reflective it was but what that range is, I'm curious to know and can't math well enough to figure out. I've always kind of wished there was a little twinkle in the sky you could literally see travelling round and round old Luna. | [
"The apparent magnitude of the full moon is −12.74. An apparent magnitude of 6.5 seems to be about the minimum visible. This means that the moon is about 305 times brighter than a magnitude 6.5 object. The object would have to have a linear size about 17.5 times smaller, which comes out to a radius of about 100 km.... | [
"Now let's say the thing emitted light could you have a very powerful yet very small light be seen from far away. Basically even if a light is small is being bright enough to be noticed by our wyes"
] | [
"Could it be smaller if the object was perfectly black? We'd only see it over the surface but we'd see it blocking the moon's light. "
] |
[
"Is Water wet? If so, why?"
] | [
false
] | null | [
"Hi unoriginalgarbage thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of t... | [
"Chemistry"
] | [
"Planetary Sci"
] |
[
"I can't seem to find an answer that makes sense: Can matter/energy come from nowhere after universal heat death?"
] | [
false
] | I keep hearing that Quantum Theory allows for quantum objects to appear out of nowhere and, just as easily, disappear. I also know that this causes vacuum fluctuation. Now, my question is: Is there a chance (may it be ever-so-slight) for vacuum fluctuation to actually create an amount of mass that doesn't disappear? Basically, quantum objects appearing out of thin nothing and staying? the idea is that after universal heat death (if it occurs, it might not in an "open" universe), there would be an infinite amount of time for such impropable stuff to happen, therefore, time would lose its meaning and if one electron or quark can appear, then, at some point, they might just appear in a way to form a solar system or an Andy Warhol picture. In any normal time frame, that would be nonsense, but if your time frame is infinite... Basically, can it happen? | [
"virtual particles don't \"appear out of nowhere\" though that is the popular presentation of them. What really happens is that ",
" particles move ",
" they spontaneously decay and interact with all sorts of other particles between measurements. But those particles never \"really\" come into existence in a mea... | [
"no, there will be particles moving about, but there won't be any way of extracting additional energy from them. They can't be used to perform work, and the system will be in the highest entropy state."
] | [
"not in the sense you're talking about. The big bang is an allowable exception."
] |
[
"Is there any animal that doesn't get startled?"
] | [
false
] | null | [
"That depends on how you define \"started\". It's not really a scientific or specific term. I'm going to define it as a sudden, short-term, and quickly reversed movement to a stimuli such as light or touch.",
"You will never startle a sponge. Other animals that may not react much or very quickly to a non-harmfu... | [
"For the sake of the question, I'll define startled as a retreat from something out of fear. Things like like sponges obviously can't however, Im wondering if there is an animal that doesn't retreat or hide."
] | [
"Than I'll repeat my answer.",
"Sponges are animals that are incapable of retreat.\nSea anemones react when touched but are incapable of retreat, as are many shellfish like muscles and giant clams.",
"Slow animals like sea slugs and star fish also will not rely on retreat as a defense as their retreat is typica... |
[
"Do spiders ever steal another spider's web?"
] | [
false
] | I just rescued a spider from my bath and blew it out the window and it happened to land next to another spider's web, which caused me to wonder if it might overpower the spider that actually made the web and use the web for itself. | [
"Most spiders are territorial, although ",
"social species exist where multiple spiders share a web",
". Some spiders intentionally ",
"steal prey from other spiders' webs",
"--some even ",
"eat the webs themselves",
". Anecdotally, I see spiders (cellar spiders) using pre-existing webs all the time--tr... | [
"The Argyrodes takes over other spider's webs and steals their food",
"This study found that some species of spiders will eat others' webs themselves if there is a low food supply",
"This Wikipedia article says that some spider families will take food from another's web, but it has no verifiable sources."
] | [
"Your link to kleptoparasitism is a good one.\nThe dewdrop spider is another example I know of. Though they have the ability to spin their own web, they will often live in the webs of other host spiders and steal their prey. ",
"http://www.americanarachnology.org/joa_free/joa_v33_n1/arac-033-01-0001.pdf"
] |
[
"What is the data on medical marijuana messing with REM sleep?"
] | [
false
] | I saw a bunch of studies and assertions that it ruins REM sleep. But I also saw stuff that says it's a miracle for sleep and anxiety and nightmares. These things don't seem to coalesce into one pattern; if it helps with anxiety, then it can't also not let you get real rest, becuase over time you would get worse anxiety from not being able to sleep. Bad sleep=more anxiety. Ditto nightmares, if you can't get real rest, then you get more nightmares. So what's going on? Is the data conflicting, does it matter who's being studied and why they're taking the drug, does it matter what particular type of thing they're taking, what ingestion method? | [
"I can't answer all of it, but one of the main reasons cannabis is looked at as a possible treatment for things like PTSD/nightmares/night terrors/REM sleep behavior disorders is specifically ",
" it inhibits REM sleep - no REM sleep means no nightmares/acting out dreams in real life/etc. It's not that the data i... | [
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7388834/",
"A survey of available data regarding sleep and cannabinoids shows pretty much what you've said:",
"\"While indeed several studies indicate chronic exposure to THC and other CB1-activating compounds appears to produce modest sleep improvement, the quality... | [
"Haven't had dreams in about a decade and i prefer it that way. I use cannabis for sleep, and it has improved my condition. The dreams i saw made me really depressed in real life, not having them has stopped me of thinking just the past, now i rarely do that anymore and it is more controlled, less emotional and ups... |
[
"Why can't you smell a burning candle wick?"
] | [
false
] | Why is it you can smell the smoke from burning wood and charcoal as it burns, but the smoke smell from a candle wick only appears after it's flame has been put out? Is it the mass of the fuel? The size of the flame? | [
"When a candle is burning cleanly, melted wax is brought sucked into the wick, where the heat of the flame vaporizes it, and it then burns when mixed with the surrounding oxygen. A little bit of the wick burns, but only if the wick becomes too tall for the flow of liquid wax to reach it.",
"When you blow out the... | [
"Good enough for me!"
] | [
"This is anecdotal but I can smell candles usually."
] |
[
"How is HF so corrosive?"
] | [
false
] | [deleted] | [
"It's a good example of why \"weak\" and \"strong\" don't tell you all you need to know about an acid. It's true that hydrofluoric acid doesn't totally dissociate into H+ and F-, and is therefore a \"weak\" acid. \"Strong\" acids need a stable conjugate base for equilibrium to favor dissociation, and fluoride (F-) ... | [
"Electron affinity is important, but isn't the whole story, as the electron affinity of fluorine is approximately that of bromine and iodine. The H-F bond enthalpy is also much higher than that of the other halogens, and H-F also forms very strong hydrogen bonds (as well as ",
"bifluoride ions",
") with itself,... | [
"Electron affinity is important, but isn't the whole story, as the electron affinity of fluorine is approximately that of bromine and iodine. The H-F bond enthalpy is also much higher than that of the other halogens, and H-F also forms very strong hydrogen bonds (as well as ",
"bifluoride ions",
") with itself,... |
[
"Is the human genome identical in all of us, and individual differences solely due to epigenetics?"
] | [
false
] | null | [
"When the human genome was originally mapped it was one version of the genome and did not account for variation. At the time it would have been too expensive and taken too long to sequence more than one human genome. Now that it's much cheaper and faster, variation is being identified by projects like the ",
"10... | [
"If only one version of the genome was mapped, did it come from one person?",
"http://en.wikipedia.org/wiki/Human_Genome_Project#Genome_donors",
"Does this mean that if given enough time (say tens of millions of years) humans will start to repeat genomes that have been present in other humans before",
"Unlike... | [
"The genome between all individuals differs to various extents (except in the case of identical twins). While we share the same general layout in terms of what genes we have, and where they go (a generalization, as people can be born with genetic abnormalities such as ",
"Turner syndrome",
", ",
"Down syndrom... |
[
"Why did NASA send Rovers (spirit, curiosity, Opportunity) to Mars but destroy Cassini?"
] | [
false
] | [deleted] | [
"The environments of Mars vs Titan/Enceladus are very different in conditions and composition. The highest classification of planetary protection goes to areas that contain liquid water or ice decided by the Committee on Space Research (COSPAR)",
"[1]",
".. As a result, any mission going to these areas or looki... | [
"I think they did it to make certain any life on the craft did not contaminate a place that possibly has life on/in it. ",
"They have the planetary protection policies in place for this. Each surface that spores can get into the atmosphere has to be under 300,000 bacterial spores. At least for the rovers. There a... | [
"It was destroyed at the end of its lifespan, there was a limited amount of further exploration it could do. And its final Saturn-grazing orbit allowed it to make some observations it would not have otherwise been able to make."
] |
[
"Trig Expression Confusion"
] | [
false
] | null | [
"You have a right triangle. You know the hypotenuse and one angle. How do you find the lengths of the two legs? Using the rules for cosine and sine:",
"cos(θ) = (adjacent length) / (hypotenuse length)",
"sin(θ) = (opposite length) / (hypotenuse length)",
"So if you want to find the length of the side adjacent... | [
"Thank you! Great explanation, never realised it was that simple!"
] | [
"If you are on a sloped surface, gravity doesn't point directly normal to the surface. Some portion is directed normal to the surface, while some portion is directed along the surface (hence why a ball on an inclined plane will accelerate down the plane, it is being acted on by the portion of gravity projecting al... |
[
"[meta] Can we add a simple new rule to the subreddit? (\"Do a quick search on Google first to see that the answer isn't readily apparent\")"
] | [
false
] | null | [
"We (the moderators) don't allow meta posts unless we're the ones to post them (yeah, we have control issues like that). That said, what you're proposing isn't a ",
" rule, it's ",
"always been part of our guidelines.",
" Feel free to ",
"message the mods",
" if you have suggestions on how we could bett... | [
"Oh, sorry about that, I had no idea. On either point, actually. Well, I willcertainly delete this thread, but I would like to suggest that you move that part of the guidelines to a place that will be more visible (i.e. the sidebar, and perhaps on the submission page)."
] | [
"I would recommend you not delete the thread. I already removed it and deleting things brings you to the attention of the spam filter. ",
"I thought we already had it on the sidebar, but apparently I was wrong. I'll let our CSS experts know to add that in, and see if we can't add something to the submission pa... |
[
"How close can someone get to being a natural clone of their mother or father?"
] | [
false
] | I've read that when genes mix, they shuffle like playing cards rather than get mixed like paint. In theory, you should get 50% of your father's genes and 50% of your mother's genes. Being that there are 7 billion people in this world, there must be some people who have a majority of their genes from one parent. Using statistical analysis, what is the maximum % that someone has of their mother or father's genes, considering there are 7 billion combinations? Sorry if this question makes no sense - I'm trying to explain it as best I. Here's where I'm getting at: If you roll dice 7 billion times, there are going to be instances where you roll several sixes in a row. Perhaps there will be times when you roll 20 sixes in a row. When you have 7 billion tries, you can get some weird results. So I'm wondering if there is someone out there who is like 80% clone of their mother or father. See where I'm getting at? | [
"What? This isn't probabilistic. You get half of your genes from your mom. You get half your genes from your dad (well, unless your a guy, and then you get slightly less than half from your dad). It's not like on average, a person gets 50% from mom and 50% from dad, but some people get 40% from mom and others get 6... | [
"It still will be 50% mom and 50% dad unless mom and dad share the same genes.",
"Sure they recombine, and each one of mom or dad's two copies has a 50% of being passed on, but in the genetic relationship between parents and offspring, you will always have the offspring be 50% identical to each parent. You do not... | [
"I think what he means is that the genes recombine in such a way during meiosis that they're very similar to the parents' genes' configuration."
] |
[
"Will listening to music through earphones really make me deaf?"
] | [
false
] | null | [
"SPL?"
] | [
"Wait, hold on. What is this referring to, the volume of the sound?"
] | [
"Wait, hold on. What is this referring to, the volume of the sound?"
] |
[
"would we be able to feel gravitational waves if our planet orbited two colliding black holes?"
] | [
false
] | gravitational waves gets weaker as they travel across space with the two colliding black holes only measuring a movement of 1/1000th of a proton, so i'm wondering if we would actually feel it if we were close to the epicenter? or would relativity get in the way? | [
"If you are so close that it would be notable you are already dead from tidal gravitational forces."
] | [
"gravitational waves gets weaker as they travel across space with the two colliding black holes only measuring a movement of 1/1000th of a proton, so i'm wondering if we would actually feel it if we were close to the epicenter? or would relativity get in the way?",
"If you can measure it many light years away you... | [
"Ok, so I did some back of the envelope calculations that I'm definitely not qualified to perform (I really want to understand this though). Sticking with converting 8 stellar masses to energy, I get 1.4 X 10 ^ 48 joules. Lets say you're orbiting at a radius equivalent to the radius of our solar system, 5.9 x 10 ... |
[
"Do we actually know what protons and neutrons look like? I know they are always depicted like spheres, but is that what they actually are?"
] | [
false
] | null | [
"When we talk about the shape and the size of a composite particle, there are a few ways to quantify them. Of course quantum mechanics says that they're not just points, they're \"clouds\" of probability density. But probability densities ",
"? ",
"Where you'd find a particle (in this case a quark) if you made ... | [
"Their electric charge distributions are close to spherical, but with a small quadrupole moment (and maybe some higher moments).",
"So we know that they're ",
" quite spheres, but the leading-order deviation is pretty small."
] | [
"It's when particles are stuck together. Like a hydrogen atom is a bound state of a proton with an electron."
] |
[
"Can you tell the race of a person by looking at their skull x-ray?"
] | [
false
] | So this was on the front page today. This has to be bogus right? I mean, I'm sure there are some indicators which could be useful, but there's no way to determine from that picture what race those people really are...is there? | [
"These are old classifications based on work that was done in the 19th century and early 20th century. The were based on the simplest of measurements, such as the cranial index (mesocephalic, brachycephalic, dolichocephalic), or the \"facial angle\", which 19th century people used as a measure of \"intelligence\" t... | [
"Yes actually you can. I took a medical forensics class and it was part of our requirements to know racial skull differences. There are 4 basic shapes of skulls: Caucasoid, Mongoloid, Negroid, and Australoid. ",
"Here's a link to the Wikipedia article."
] | [
"True, though perhaps it would be better to say you can infer something about their ethnic heritage. We sometimes use the word \"race\" to mean \"ethnicity,\" but we also use it in other contexts where it doesn't fit as well (consider people of mixed ethnicity).",
"But yes, there are noticeable differences in th... |
[
"Is there an upper limit for temperature? Like how absolute zero is the lower limit."
] | [
false
] | In my science class my teacher was talking to us about temperature, and how absolute zero is the lowest temperature possible. He also said that there is no upper limit. That doesn't seem quite right, because temperature is a measurement of the average velocities of the molecules in the substance. Furthermore according to Einstein the fastest speed something can travel at is the speed of light, so to me it seems like there should be a limit to how hot something can get. Any information on this would be greatly appreciated. | [
"I remember thinking the same thing when I was in school. Then I went to university and learned relativity and was disabused of the notion. But you're asking the right questions.",
"The answer to your question is this: temperature is defined not in terms of the average speed of the particles but in terms of the a... | [
"Well, let's see. The LHC currently operates at 4 TeV so all we need to do is go to Wolfram Alpha, type in \"4 TeV / boltzmann's constant\" and we get the answer. It's about 10",
" K.",
"That's hot!"
] | [
"The Planck temperature is not necessarily anything special. If you look at the ",
"article",
" that the Planck temperature wiki page links to as a citation for a statement tantamount to \"the Planck temperature is special\", you'll see that it presents ",
" candidates for an upper temperature limit, one of w... |
[
"Is it possible to be so far away from a light source as to exist \"in between\" the light rays?"
] | [
false
] | This is hard to explain without visuals but think of an exploding grenade. The farther away from it, the greater chance of not being hit by shrapnel because you are "in between" the path of the projectiles. | [
"If it's a continuously shining, isotropic (emitting evenly in every direction) light source, then the farther away you go, the less frequently a photon will hit you. You're basically on the right track, the intensity of radiation (and thus the surface density of photons hitting a surface) decreases with the square... | [
"To expand on this point, while the intensity does decrease (think number of photons hitting a 1 cm radius plate), quantom mechanics tells that the probabilty wave function of the light gives you some nonzero chance of a discrete interaction on the plate. So on a fundamental level, it is not that photons are rays ... | [
"No, stars emit light isotropically (equally in all directions), and even if they didn't, stars rotate so the \"dead zone\" would move. "
] |
[
"What happens to a mammal after injection of proteolytic enzyme?"
] | [
false
] | I've concluded brief search before asking and found only a few (seemingly) controversial reports about intravenous injection. In some cases it promotes blood clotting. In other, on contrary, their properties are described as fibrinolytic. Does that mean that blood clotting cascade is their main (only) target in bloodstream? Would the result of intramuscular injection be similar? | [
"Not sure what you're getting at with this question, but it would depend on which proteolytic enzyme you're talking about. Any enzyme has a characteristic set of substrates that it accepts, while other molecules can't be effectively cut by that enzyme. This is why you are seeing that some proteases are thrombogenic... | [
"My question is purely hypothetical, I'm not going to conclude any experiments. ",
"From one side, it arises from of eating pineapples and specific feeling associated with it -- when your mouth internal surface is kind of partially digested with its juice. Few culinary recipes also use pineapple juice as meat ten... | [
"Well, introducing large amounts of most enzymes probably won't do much. Injecting proteins (enzymes are proteins) into the blood is how we can get animals to make antibodies against those proteins that we can then purify. The enzyme would get denatured fairly quickly and degraded in the bloodstream. The enzymes... |
[
"Why does the voltage matter in powered devices?"
] | [
false
] | null | [
"A simple way to look at it is using ohms law which is V = I*R",
"This means that if I have some device with 110 ohms of resistance then a 110 V circuit will draw 1 Amp of current. But if you plug the same device into a 240V plug it will draw 240/110 = I = 2.18 Amps. This is a very simplified view but can be used... | [
"As an analogy, think of a water faucet instead of a battery. Even if two faucets can deliver the same flow rate (ie current), if you connect a sprinkler to a faucet that has a higher or lower pressure (ie voltage) than the sprinkler was designed for, it will not work correctly. If the pressure is too low, water wi... | [
"Supplying an insufficient voltage (eg. 240 V device into a 110 V outlet) will almost certainly not work and may or may not damage the circuit. It depends on the circuit. As an example, if you have some diodes or transistors in there, decreasing the input voltage might change the biasing and send current to places ... |
[
"Would the electromagnetic field diverge into its component fields at a low enough temperature or some conditions?"
] | [
false
] | null | [
"no. any changing electric field will generate a corresponding magnetic field (and vice versa). this is valid at 0K in absolute vacuum and a fundamental property of electromagnetism."
] | [
"Electric and magnetic fields are manifestations of the same force. They are inseparable - it's the relativistic speed of the observer that makes them seem different."
] | [
"it's the relativistic speed of the observer that makes them seem different.",
"That's only completely accurate for classical electromagnetism. It isn't true for the magnetic moments of fundamental particles."
] |
[
"Does the dark energy make it possible to have a closed universe that doesn't re-collapse?"
] | [
false
] | Dark energy, matter and radiation determine the total energy, which in turn determines the geometry. But since the dark energy has an opposite gravitational effect it seems that this would make it possible to have a closed geometry without a big crunch. | [
"yeah but it can make you have a big freeze. i.e everything expands until there is universal heat death."
] | [
"Wouldn't it make it inevitable? If things continue to spread out forever and all stellar fuel is eventually exausted, and all black holes evaporate won't there no longer be any sources of heat?"
] | [
"Why is a big freeze called a heat death? Shouldn't it be a cold death?"
] |
[
"What causes the iconic mushroom cloud shape?"
] | [
false
] | Why don't nuclear bombs just have a larger version of normal explosions? | [
"d4m1ty's response",
"A large enough conventional explosion also results in a mushroom cloud. You've got a mass of super-heated air that rises, carrying ash and dust skyward, resulting in a mushroom shape if the plume is large/hot enough."
] | [
"d4m1try's explanation is wrong. But yours above is correct. The mushroom is not a wave effect, instead it's caused by rising hot air.",
"If there is no large volume of heated air in the explosion, then there may be smoke and debris, but there will be no mushroom shape. Compare IED explosions versus burning ... | [
"Intense heat. Buoyancy forces carry the smoke upwards, but as the temperature of the atmosphere decreases with height, the smoke at the edge of the rising column slows down and spreads out. Hot smoke from the centre continues to rise and sucks up surrounding air and smoke. This creates the stem of the mushroom. "
... |
[
"Why does water continue to steam below 100 celcius?"
] | [
false
] | So I was making a cup of coffee today. To my knowledge, you cannot boil water above 100 degrees in a kettle because energy will be taken away by steam as quickly as you can put energy in. So I assume the water I poured was 100 degrees, probably slightly less. By the time I had mixed in a bit of chilled milk, it certainly had to be less than 100 degrees. But for the new few minutes, it continues to steam. Surely this means the water is changing from liquid to gas at below 100 celcius, so why does it happen? | [
"Steam is virtually invisible. What you see coming off hot water is water vapor."
] | [
"The water molecules are always moving, and every so often one of them will have enough energy to break away and become a gas. This is constantly happening, and we call it evaporation. When you add heat to the water, you increase the motion of these molecules, and, as a side effect, increase the rate at which som... | [
"Because if a collection of particles has a certain global temperature, that doesn't mean that they are all going exactly the same speed. Some are going much faster than average and some much slower. So even at lower temperatures, you can still find hot fluctuations of particles that have enough energy to leave the... |
[
"Why does my Stainless Steel flask say \"Alcohol based liquids should not be stored longer than 12 hours\"?"
] | [
false
] | I'm just curious what reaction occurs and how bad it is to leave the liquid in long term. It also says "Do not store acidic or alkaline-based juices or citrus fluid". Anyone know the reason for that? Edit 1: Just wanted to thank this community. I'm quite happy about the responses I've received. | [
"If it is indeed stainless steel, the ability to form a passive layer has been shown to be strongly influenced by the presence of hydroxylic organic solvents (ie it's not as 'stainless' when you put ethanol in it) [1]. Since stainless steel contains both iron and chromium, and chromium is particularly adept at ripp... | [
"I know some people who could. I'll ask them if they can spare some time on the instrument. Seriously."
] | [
"Perhaps it is made of aluminum with a thin stainless steel coating on the outside? I would assume this would allow them to call it stainless steel and it would be cheaper for the company than making them entirely stainless steel."
] |
[
"Help a guy battling OCD get rid of his fears of germs/bacteria"
] | [
false
] | null | [
"I approve of most of what you've said, but:",
"your body is absolutely infested with bacteria",
"I would say ",
" rather than ",
". Your body is inhabited by a host of bacteria called the ",
"Normal Flora",
". One of the ways these bacteria help you is by benignly occupying space that might otherwise b... | [
"I approve of most of what you've said, but:",
"your body is absolutely infested with bacteria",
"I would say ",
" rather than ",
". Your body is inhabited by a host of bacteria called the ",
"Normal Flora",
". One of the ways these bacteria help you is by benignly occupying space that might otherwise b... | [
"I feel for you SpamKing, my ex was mildly OCD so I understand the frustrations that go hand in hand with that.",
"So with this in mind, I would like to cover some of the 'other information on why I shouldn't be so overly concerned about bacteria all the damn time'.",
" Every day, new uses are being found for "... |
[
"How does the EM Drive break Newton's Third Law?"
] | [
false
] | null | [
"To be propelled forward, you need to shoot something backward. Any \"reactionless\" drive violates this principle ",
"."
] | [
"But doesn't it send microwaves out the back? Aren't they the propellant?"
] | [
"If it does, then it's not reactionless."
] |
[
"Is most space debris traveling the same direction? And could we take advantage by shielding only one side of our spacecraft?"
] | [
false
] | null | [
"No.",
"In low orbits, most of space debris came from two major events: the Kosmos-Iridium collision and the takedown of the Fengyun-1C satellite.",
"https://wattsupwiththat.files.wordpress.com/2010/06/space-debris-charts.gif",
"The Kosmos-2251 satellite was already defunct. Iridium 33 was still working. In 2... | [
"If you are talking about orbital debris, which can strike satellites and break them, then yes it is mostly going in the same direction. That is because we mostly launch satellites in the same direction as the rotation of the earth (it costs a little less fuel in that direction to get something into orbit). But not... | [
"They call it \"Dark Flow\", the possibility that galaxy clusters are all flowing in a common direction. There have been studies done to prove and disprove it. Though some claim that they have evidence, or at least some grounds to support the idea."
] |
[
"Why have I had hiccups on and off for four hours?"
] | [
false
] | null | [
"Please consult with a doctor regarding diagnosis issues."
] | [
"this is not a diagnosis tho, i am just wondering about the biology. "
] | [
"oh, it just sounded like a personal diagnosis is all. In that case we've had a recent hiccup thread ",
"here"
] |
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