title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Why can't we taste and smell like we see and hear in dreams?"
] | [
false
] | null | [
"Do you have evidence that this is the case?"
] | [
"We rely much more on our senses of seeing and hearing when we develop a model of our surroundings as apposed to tasting or smelling. When dreaming, we create an imaginary model in our heads. Our brain creates a model based on what it is accustomed to picking up.",
"People that are blind rely more on their sense ... | [
"I smell and taste in my dreams - it's rare, but has happened."
] |
[
"How old is the universe according to itself?"
] | [
false
] | Hi reddit! First off i understand the universe is about 14bil years old, but thats according to earths frame of reference correct? But that would be heavily influenced by time dilation due to our speed (planet/system/galaxy) and the gravity surrounding us correct? Is there any way to find out how old the universe woul... | [
"The age of the Universe is determined by a combination of observed, cosmological measurements, including the density of matter, radiation, dark matter, and dark energy. These values are all frame independent, so the calculated ages of the Universe is also frame independent. "
] | [
"i understand the universe is about 14bil years old, but thats according to earths frame of reference correct?",
"That's according to the center-of-momentum reference frame of the CMB near Earth, which is close to but not exactly the same as the Earth's reference frame. The measured age of the universe is longes... | [
"Why would a reference frame outside the universe not be valid ? Is it because we simply have no way of knowing how that would work and therefore be pure imagination?",
"Right, it can't even be defined. What would the coordinates be for the reference frame? They could not be labelled using the real numbers, as ... |
[
"What is the best material/way to make durable records that last a very long time?"
] | [
false
] | Data on the internet is inaccessible without the necessary devices, paper degrades, hard drives degrade even faster. At this point I think if I want something to stick around the best bet is to carve it into stone. | [
"See what the ",
"Long Now Foundation",
" has cooking up. Their 10K year clock is up your alley.",
"Also ",
"long-time nuclear waste warning messages",
".",
"In general, inscriptions into an inert metal and stored somewhere dark, cool, and dry are your best bet for extreme long-time preservation.",
"... | [
"Ceramics might work well also: they are stable and chemically inert, and would be much cheaper to make than noble metals.",
"E.g. we have plenty of ceramic written records from 4,000+ years ago. ",
"- ",
"https://en.wikipedia.org/wiki/Cuneiform",
"- ",
"https://en.wikipedia.org/wiki/Clay_tablet",
... | [
"Well, not ",
". Eventually quantum tunneling will smooth out the record surface and, if it's in space, congeal it into a smooth sphere of material. ",
"So basically forever. Hopefully OP will have achieved their goal with it by then!"
] |
[
"What determines the size of a black hole? Since a singularity is infinitely small, why do black holes differ in size?"
] | [
false
] | [deleted] | [
"In my favorite units to think in, it's approximately 3km/solar mass. So the Schwarzschild radius of a black hole with the same mass as the sun is 3km. For a black hole that's 10 times as massive, the radius is 3x10 = 30km."
] | [
"In my favorite units to think in, it's approximately 3km/solar mass. So the Schwarzschild radius of a black hole with the same mass as the sun is 3km. For a black hole that's 10 times as massive, the radius is 3x10 = 30km."
] | [
"I love that the Schwarzschild radius of a human is smaller than an atom."
] |
[
"How high can a balloon go?"
] | [
false
] | [deleted] | [
"That depends largely on the material of your balloon. Generally, helium balloons ",
" theoretically rise to the very top of the atmosphere, but in practice they pop before they get there as the balloon volume starts to exceed material tolerances.",
"If you're looking for a more specific number, the current wor... | [
"Using known materials, how high can a balloon go? Would it help if you used a rigid or semi-rigid structure and transitioned from helium to vacuum, as you increased altitude?"
] | [
"The material used in the current world record was specifically chosen for that exact purpose, so I find it highly unlikely that it's possible to go much higher using any others. If there is, it is beyond our knowledge.",
"A rigid structure is generally counter-productive if you're shooting for altitude. It's inc... |
[
"A question regarding the pinnacle of nanotechnology vs Biology"
] | [
false
] | At the pinnacle of nanotechnology, would there be a difference between it an biology? I guess what I'm asking is that if we were to perfect the technology, could we artificially create the building blocks of life or is there something more complicated about dna/rna/etc. that would make it impossible? Could nanotechnolo... | [
"Could you clarify what you're asking? As far as I can tell, there are two things you might mean:",
"1) Will our nanotechnology become sufficiently complex that we will come to consider it \"alive\", even if it's still all \"machinery\", and not strictly speaking \"biological\"?",
"2) Will we ever be able to sy... | [
"Yeah, that's pretty much what I'm asking. Basically, will it be possible for us to build \"life\"?"
] | [
"Which one? Those are two different questions."
] |
[
"Suppose we (were) visit(ed) (by) an intelligent race of aliens. How could we possibly communicate with them?"
] | [
false
] | I think this is comparable to explorers encountering an indegioness people, but it couldn't be that simple, could it? | [
"Richard Feynman covers this in a book. Basically, start with math, because math should be universal.",
"Say 'tick one', 'tick tick two', 'tick tick tick three', etc. They'll probably figure out the pattern if they're intelligent and sense sound.",
"From there you have building blocks to map mathematical cons... | [
"If they're using radio waves or getting here in flying saucers, they know math."
] | [
"If they're using radio waves or getting here in flying saucers, they know math."
] |
[
"Shouldn't Hydrofluoric acid be the strongest acid?"
] | [
false
] | I am going to divide this into the two most common explanations I get when asking this question and follow it up with why I don't think that the explanation holds up: This explanation bothers me on quite a few levels: The F atom is not attracted to the Hydrogen atom: It's attracted to the Hydrogen atoms electrons. To m... | [
"First of all, by most considerations the hydrohalogens are not ionic in character. Also, greater bond distance weakens the bond, which is in part why its easier to create the anions of the higher halogens.",
"However, the crux of the issue is that while fluorine has the highest electronegativity, it doesn't have... | [
"Also, it is extremely dangerous to skin/mucosa, so we have to be very careful when using it intraorally.",
"wait, what? HF gets used inside peoples' mouths?\nI'm guessing it's applied as a paste so that it's easy to control, but I hope you have a lot of calcium gluconate or other neutralizers on hand. ",
"I us... | [
"The most sensible explanation I've come across is that HF does in fact have a higher tendency to donate a proton to water (e.g. is a stronger acid), but because the resulting fluoride anion forms a hydrogen-bonded ion pair with the hydronium ion, the solution behaves as though the hydronium ion concentration was l... |
[
"Does a chameleon shooting its tongue at an insect have to calculate how far the insect is, or does it just shoot until it feels that it made a hit?"
] | [
false
] | null | [
"In the same way humans brains do, minus the complexity. I guess, for example, imagine someone throwing rocks at a signpost. They don't really calculate the distance between the sign and themselves, they just throw the rock however hard they believe necessary to hit the sign. If they miss, well they learn quick and... | [
"It's brain is an analog computer that performs calculations, isn't it? "
] | [
"Chameleons lack the higher brain functions to calculate distance in any meaningful, mathematic sense. They simply operate on instinct and experience, much like how you don't calculate the relationship between force, drag, and gravity when you throw a ball. You just throw it harder or softer based on where you want... |
[
"Why did we evolve to go through puberty? Why don't we just come out ready to procreate?"
] | [
false
] | Why do humans go through puberty? Wouldn't it make more sense, from an evolutionary point of view to allow procreation as early as possible? | [
"In complex foragers such as ancestral humans, it was important to have a development period in which the individual fine-tunes the techniques that will help him/her survive. If we entered into puberty right after birth, we wouldn't have had the time to establish our own lives and would most likely not have the res... | [
"It would be very expensive (energy-wise) to try to do that at the same time as all the other important developmental milestones that have to be reached early in life. Species like humans invest in long term survival (unlike short lived animals such as mice) with the trade-off of slower maturing. "
] | [
"All primates in undergo puberty - or scientifically known as ",
"sexual maturity",
" of varying lengths - in fact most mammals (multicellular organisms) do, but it is especially noticeable in the long lived ones. ",
"Besides the reasons specifically relating to humans stated below, primates/humans also need ... |
[
"Is max energy transfer between a driving force and a damped oscillator at natural or resonant frequency?"
] | [
false
] | null | [
"The maximum energy transfer is on resonance."
] | [
"By resonance do you mean at resonant frequency or at natural frequency? \nIf you mean resonant, what’s the mistake with this?\n",
"https://physics.stackexchange.com/questions/109242/why-maximum-energy-transfer-at-natural-frequency-even-if-max-amplitude-occurs-be"
] | [
"That's interesting. I didn't check their calculation, but I don't see any obvious flaw in it."
] |
[
"Why and how crystallization of silver and gold happen?"
] | [
false
] | I learnt that this can happen to ancient coins, and they become very brittle. | [
"Metals, even though they don't look like it are actually all crystals.",
"I would assume (and this is speculation) that when you pour molten gold or silver into a shape, the atoms didn't have enough time to rearrange themselves to their proper crystal structure due to quick cooling. Over time due to external fac... | [
"Good answer. I would add that the hall petch relationship means that, if anything, the larger/coarser crystallites result in greater ductility w.r.t. %elongation at fracture increasing. Grain boundary impurity segregation and corrosion seem like the best explanations."
] | [
"Good answer. I would add that the hall petch relationship means that, if anything, the larger/coarser crystallites result in greater ductility w.r.t. %elongation at fracture increasing. Grain boundary impurity segregation and corrosion seem like the best explanations."
] |
[
"AskScience, are there any concrete studies on whether milk is good for us or not?"
] | [
false
] | I've heard both sides saying it's good or bad, but I can't find a definitive answer. | [
"Milk is fantastically good for people if you are strictly talking about energy content. It was so good that mutant alleles that allow digestion of lactose in late life spread like wildfire in early human populations (Sabeti et al, 2006 and 2007). Utilizing alternative food sources or increasing digestive efficienc... | [
"Milk actually is fortified with Vitamin D, it is not found naturally."
] | [
"I'll throw in a little information: if you want to get the most bang for your buck, yogurt and certain types of cheeses (but not most) may be among the most useful types of dairy to consume given that they also contain bacteria that in many studies have been shown to have beneficial effects on our health.",
"Now... |
[
"Can you fire an unmodified gun in space?"
] | [
false
] | Is oxygen required for the combustion? Are there other issues? Edit: Thank you to all who have contributed thus far. It seems like the other common considerations are: 1) Pressure / the vacuum of space 2) Extreme temperature 3) The properties of the materials involved 4) The mechanics of the gun / firing mechanism | [
"Mythbusters just did this a few weeks ago they put a revolver in a vacuum chamber and fired it. End result was it fired just like it did without vacuum but seems to have less resistance in the vacuum and did a tiny bit more damage to the end of the chamber than the other one.",
"http://www.discovery.com/tv-shows... | [
"Absolutely. Modern (smokeless) ammunition uses nitrocellulose, with maybe some nitroglycerin added. All oxygen needed for combustion is contained within the cartridge. The bullet would probably go even faster than it would on earth because there wouldn't be air in the way to slow it down. Nitrocellulose has 3 simi... | [
"On a tangential note: would there be a heat problem with repeated firings? It seems like firearms wouldn't be able to dissipate heat as quickly without a fluid medium to conduct it away. So you wouldn't be able to safely fire it as fast as you would in air."
] |
[
"Would it be feesible for us to program a machine learning computer to understand all combinations of elements, chemicals, and compounds, and then have it run simulations to determine solutions for stuff like curing cancer, or repairing the ozone, or something?"
] | [
false
] | null | [
"This is a single, typically average protein sequence:",
"MEEPQSDPSVEPPLSQETFSDLWKLLPENNVLSPLPSQAMDDLMLSPDDIEQWFTEDPGPDEAPRMPEAAPPVAPAPAAPTPAAPAPAPSWPLSSSVPSQKTYQGSYGFRLGFLHSGTAKSVTCTYSPALNKMFCQLAKTCPVQLWVDSTPPPGTRVRAMAIYKQSQHMTEVVRRCPHHERCSDSDGLAPPQHLIRVEGNLRVEYLDDRNTFRHSVVVPYEPPEVGSDCTTIHYNYMCNSSCMGGMNRRPILTIIT... | [
"I've spent the better part of the past four years researching a single protein using some pretty big supercomputing clusters. I've got terabytes of data, plus backup, for this one protein.",
"All of that was centered around seeing how ONE amino acid change would affect the protein.",
"And that project is stil... | [
"Honestly one of the best answers I have ever read."
] |
[
"Does tagging a protein with GFP alter its mechanics?"
] | [
false
] | From what I understand it is near the tail end of the protein coding sequence, but I also thought that GFP was fairly large. My question more pertains to does it interfere with protein movement or localization at any point? | [
"It can and often does. You should always check the functionality of the protein you have tagged, usually be looking to see if a tagged protein replicates a mutant phenotype.",
"Oftentimes N-terminal tags will act differently from C-terminal tags. You can also add GFP into the middle of a protein, the N- and C- t... | [
"That is theoretically possiblble. Protein localization is most often accomplished by signal sequences (i.e. ",
"NLS",
") thus if the GFP tag interfered with the binding of this sequence to its receptor, then yes. Protein movement is slightly more complicated because that term is rather broad. However, the GFP ... | [
"There is an interesting paper on the protein responsible for flowering plants. The investigators found that after a transition from short days to long days (winter->spring) that a soluble protein, Florigen, was generated in the stroma of the leaves and traveled all the way to the apical meristem. What is pertinent... |
[
"In what way does the regulation of cell differentiation in a Hydatidiform mole differ from normal tissue and embryo growth?"
] | [
false
] | Somehow, the order of switching on and off pathways of cellular differentiation is all screwed up and chaotic, yet enough order remains that distinctive patches of coherently organized tissue occurs? What is going on, and what is directing the genes this way, if they are involved? | [
"So a complete HM(using this abbreviation bc I hate spelling it) is caused by an empty ovum fusing with either 2 different sperm or with 1 sperm that duplicates= 46XX or 46 XY. Basically, only the father's chromosomes are in there. In a complete HM p57 is absent due to the fact that it is maternally transcribed and... | [
"I think you're confusing yourself by focusing on Hox, given that Hox is more important in segmentation than in organ identity. ",
"What's really important is the nature of epithelial-mesenchymal signaling and invasion processes that are associated with placentation. Some of this is probably regulated or mediated... | [
"Well, differentiation of stem cells (like wound healing and cancer) is a chromatin remodeling process at DNA. It's not screwed up and chaotic; it's orchastrated. What happens here is that just after fertilization the recombinant DNA is not viable, so what would normally be a highly specific mechanistic cascade dea... |
[
"How do we measure speed in space?"
] | [
false
] | All speeds on Earth are relative to Earth, but once you're in space, how can you see how far you have traveled, and therefore how fast you are traveling when everything around you is moving in different directions, at different speeds? | [
"That's a great question! The answer is: you don't! There is no such thing as absolute velocity. There is only relative velocity. That is, you can only say how fast something is moving ",
" something else. Physicists say it as, \"there is no preferred reference frame.\" This is actually a very deep, fundame... | [
"Do space shuttles use any measurements of speed in space? ",
"I would think that it could be possible if you choose a reference from (e.g. distance from earth, or any destination) and measure the distance based on satellite communication. But the more I think about this, the more complicated it seems."
] | [
"Space shuttles are in low Earth orbit, so they're still basically right beside the Earth, so we still measure velocity relative to the Earth."
] |
[
"Surge of adrenaline. What is happening chemically in my body?"
] | [
false
] | [deleted] | [
"The first part of the process is what I'm still not clear on, but somehow you perceived the sound as a threat. As a result, the sympathetic nervous system directly stimulated the adrenal medulla, which released adrenaline/epinephrine into general circulation. From there, epinephrine has a lot of actions, most of w... | [
"This",
" and ",
"this",
" should get you started. If you still have questions, let me know."
] | [
"Out of curiosity, is it possible to safely have some kind of sustained flow of adrenaline into your bloodstream that would cause your body to continually undergo increased lipolysis leading to weight loss? I would assume an obvious side-effect would be to be incredibly energetic and jumpy while you were undergoing... |
[
"Minimum Orbit"
] | [
false
] | Is atmospheric drag all that determains what is a minimal stable orbit? Theoretically, if a planet had absolutely no atmosphere could you orbit arbitrarily close to the surface given sufficient horizontal momentum? | [
"Yes, that's correct. For example the Apollo Command Module had its perilune at about ",
"15km altitude",
" above the Lunar surface. Of course, you have to watch out for mountains too."
] | [
"Planets, moons and asteroids are not perfect spheres. The variations in mass distribution disturb orbits and make low orbits unstable over time. Also, perturbations in the trajectory due to the influence of other gravitational bodies has some impact."
] | [
"I hadn't thought about how irregularities in a planet make low orbits unstable. That is neat!"
] |
[
"How does the transmission of data back to Earth, including digital images, from something like the Mars Rover or the Hubble work?"
] | [
false
] | [deleted] | [
"There's an article ",
"here",
" on the Deep Space Network, which is frequently used to communicate with long-distance probes."
] | [
"Travel time limits speed because it is a time put on top of every transmission. Suppose you have a command that would take half a second to send but you are 5 light minutes away; it takes 5 minutes and half a second for the command to be received. You can continue to send longer commands (a command taking an hour ... | [
"Info from the rover is relayed to the MRO (Mars Reconnaissance Orbiter) which sends the data to Earth's Deep Space Network."
] |
[
"Is there a search engine that only returns results from peer-reviewed sources?"
] | [
false
] | null | [
"Google scholar"
] | [
"The thing with Google Scholar is that it doesn't only return peer-reviewed sources, it also returns technical reports, arXiv papers, and the like, which have not [yet] been vetted by peer review.",
"Closer to what the OP looks like is Web of Knowledge:\n",
"http://www.webofknowledge.com/",
"\nbut this one is... | [
"I primarily use ",
"scholar",
" and ",
"pubmed",
". Scholar is kind of a kitchen sink while pubmed is medical and health sciences related. The journals have webpages that you can use to see if they are peer-review journals. Which journal is peer reviewed and which is not is something you learn as you read ... |
[
"Why am I a picky eater?"
] | [
false
] | I've been a picky eater my whole life, I've gotten a bit better over the years, but there are still a lot of foods I just won't touch. What is the root cause of being picky? Is my tongue just physically made to not like those certain foods or is my own personality to blame because I haven't branched out enough? | [
"No. You were never introduced to these foods and are stuck in a rut. You won't like every new food, but there is no physical reason you can't eat more then waffles and hotdogs the rest of your life.",
"Cowboy up and eat something with flavour."
] | [
"Not really a scientific question, so the answer isn't scientific either: it's all about being accustomed to different tastes, textures, and one's mental approach to food. Selective tastes as far as evolutionary biology goes only accounts for pretty obvious stuff - rotting and food that's \"gone bad\".",
"As for... | [
"http://www.cracked.com/article_19224_6-wuss-behaviors-that-were-once-badass-survival-instincts_p2.html",
"Hope this helps!"
] |
[
"What inputs are used for weather forecasting models during the \"heat dome\"?"
] | [
false
] | The 24h/48h forecasts ended up being quite accurate where I live in the U.S. Pacific Northwest, and even several days out forecasts called for record-breaking temperatures. Was anything different done to generate the forecasts, such as using a different approach tailored for "heat domes", or do the standard forecasting... | [
"The short answer is: ",
". For the long answer, that delves far too deeply into the world of weather prediction for most people to care, read on...",
"The thing about us humans is we like to categorize things. We like to say things like \"That's a cold front\", \"That's a cirrus cloud\", \"That's a ",
"\", e... | [
"We can't say \"oh, climate change caused this exact thing\", but we can say \"climate change is causing an increase in extreme weather events, and this is an extreme weather event that's outside the normal bounds of recorded/predicted weather\""
] | [
"As a follow on to this, while the numerical weather prediction codes are better, there's also been a lot of effort expended towards incorporating the rapid increase in the amount of satellite and other remote sensing data into the models (what research and industry calls 'data assimilation'). So, for example, if ... |
[
"Bobby McFerrin demonstrates the power of the pentatonic scale in 2009 World Science Festival. Why is Pentatonic scale more natural to humans than Heptatonic scale ?"
] | [
false
] | I refer to this video: In this video, Bobby McFerrin sings two notes and lets the audience figure out the third, and gradually the audience settles on the pentatonic scale. I was wondering why didnt they settle on the heptatonic scale, which pretty much every child gets exposed to ? Why is the pentatonic scale more nat... | [
"Musician here.",
"Heptatonic and pentatonic simply refer to the number of tones in the scale. There are many different heptatonic and pentatonic scales. The one most people refer to when they say \"pentatonic\" can be thought of as being the black notes on a piano, repeated over and over as you move up the key... | [
"Is it really more natural? Or are we just more familiar with it?",
"A few things I notice.\n He provides 2, the audience sing the 3rd which is just one tone further up - they are following a simple pattern. The 4th note ( the low one - a B flat) he provides, which also sets the whole scale into the pentatonic."... | [
"Alright, a complete music theory noob who is greatly interested in this conversation, but cannot keep up. Would anyone wish to define and illustrate the differences between the Heptatonic Scale and the Pentatonic Scale?"
] |
[
"Why can't we create a chemical reaction system that mimics metabolic use of ATP to use as an alternative energy source?"
] | [
false
] | The metabolic pathways of ATP formation and use seem extremely efficient chemically. Is it possible to create a series of chemical and biological reactions that mimic the ATP reactions in organisms for use in other mediums such as cars or to power a light? | [
"It's important to note that ATP isn't really the ",
" of energy. It's an enzyme that helps to ",
" energy. It's constantly being recycled between forms (ADP, ATP).",
"The energy isn't just magically coming from ATP, it must be added in from an outside source. Carbohydrates, for example, are a \"storage\" ... | [
"Most likely the circumstance. For something like coal, for example, the storage mechanism is relatively stable. For something like ATP, you would need to have conditions that prevent breakdown of the coenzyme, and a system set up to operate that, plus mechanisms to transfer that energy.",
"With the current sys... | [
"I'm guessing that the cost of the biological fuel would be significantly higher with the citric acid cycle than with, for example, fossil fuels, which is why it hasn't even been considered as an alternative energy source. I don't remember the numbers, though- I haven't taken a biology course in quite some time. Co... |
[
"How do physicists measure the temperatures of experiments approaching absolute zero?"
] | [
false
] | Pretty simple. Is there some sort of special equipment used to measure these temperatures? It's pretty safe to say they don't stick a mercury thermometer in there. | [
"There are a few ways, either based on calibration or on fundamental physics. For example, one could measure the random noise in the signal passing through a wire, which is related to the temperature. Or you can increase the pressure in your fridge until the helium freezes, and that pressure is calibrated to temper... | [
"For clouds of cold (uK) atoms they can use something called \"time of flight\" measurements. Generally a cloud of cold atoms is suspended in a magneto-optical trap, and the cloud has some velocity distribution. When you turn the trap off, the cloud falls under the influence of gravity and spreads out because the a... | [
"It's a destructive measurement in that you don't recover that particular cloud, but you know that if you prepare another cloud of atoms using the same conditions, it's at the same temperature that you just measured."
] |
[
"does energy travel faster than light?"
] | [
false
] | null | [
"This has been answered before (by me no less!). Whether you're talking about the speed of an object, energy, or even information, the answer is that you can't cheat the speed of light with a really long stick.",
"http://www.reddit.com/r/askscience/comments/vib9q/is_information_bound_by_the_speed_of_light/c54qj1... | [
"The speed of sound in neutron stars (which are extremely dense) is relativistic."
] | [
"It would not move instantly, and it would lag by much more than a second. Physical properties of the object would determine how fast your compression wave moved through it."
] |
[
"Can footwear worn as a child affect the way one's feet develop?"
] | [
false
] | [deleted] | [
"I think the answer is \"probably, but it's hard to prove.\" The best example I can think of off the top of my head is ",
"foot binding",
" which was popular in China in the 19th and 20th centuries. That's certainly an extreme example, but I think it shows \"proof of concept,\" if you will.",
"That said, it w... | [
"Yeah, but foot binding results in bone breakage. I think it may be more of a soft tissue issue. Hey, that rhymes. "
] | [
"My personal experience: yes, on me.",
"Bad shoes that does not sustain arch, the foot bend inward a little bit. Problems to the knee as adult."
] |
[
"How do tsunamis work and, more specifically, why wasn’t there a large tsunami after the earthquake off the Alaskan coast?"
] | [
false
] | null | [
"Shaking doesn't cause a tsunami, earthquakes generate tsunamis because they move a chunk of seafloor vertically.",
"The earthquake in Alaska was a strike-slip earthquake, meaning that the two sides of the fault moved horizontally past each other. There isn't much vertical motion, so no big tsunami.",
"Strike-s... | [
"The Pacific has a number of tectonic plates and Alaska is a fairly active location. ",
"The reason that there was a large earthquake but no Tsunami has to do with the type of tectonic movement that cause the quake. \nThe one that occurred in Alaska a few days ago was the result of a Strike-Slip Fault within the ... | [
"A tsunami usually appears when an ocean suddenly has a bunch of space that is not filled with water, such as when tectonic plates move apart (accompanied by an earthquake), or when a meteorite plunges into water.",
"The water quickly rushes to fill the vacuum and this motion produces violent gigantic waves. An e... |
[
"Can a wave's wavelength be smaller than Planck length? And why?"
] | [
false
] | null | [
"No one knows the answer to this question.",
"The Planck length just represents the scale at which our current models break down, the scale at which a theory that combines gravity and quantum mechanics will be needed. What the new models that work at that scale will tell us about physics at that scale or smaller... | [
"Your second question implies that you think it could not be; why?",
"To begin to answer your first question: there is no experimental evidence that a wave's wavelength (or particle's De Broglie's wavelength) could not be smaller than the Planck length. There are theoretical arguments based on our knowledge of ... | [
"Yes, it can, but given our current measuring prowess, we wouldn't be able to measure it.",
"Planck length is not the length of anything in particular. In any theory that has G, h and c as constants, the Planck length, or small multiples of it, is likely to turn up just because of dimensional analysis — it's the ... |
[
"Do animals have emotion?"
] | [
false
] | null | [
"For an interesting academic read on the subject, see Painter and Lotz's book ",
", which is the most oft cited resource on the subject of animal interiors. ",
"You can read the fulltext here and download as a PDF.",
"People who study this, Phenomenologists (in the realm of psychology specifically), often bui... | [
"I like your approach, even if it doesn't really belong in this reddit. I'll make a longer version.",
"The scientific way to approach this question (which is the only correct way here in askscience) starts with defining \"emotion\". This is really hard.",
"The non-scientific way is much easier: When you look at... | [
"Of course. That's really all they have, no or very little thought, just instinctive and conditioned responses that are created by emotion."
] |
[
"How do we get our gut bacteria?"
] | [
false
] | Are we born with it, do we acquire it in the womb or from the food we eat over time? | [
"Breast milk is not sterile. ",
"Okay, but how do ",
" bacteria get into the milk glands?"
] | [
"Dendritic cells are antigen presenting cells and do not traffic live bacteria anywhere unless there is a serious infection. Breast milk is sterile as its secreted. You pick up your gut microflora commonly from birth (as mentioned above) and from your surroundings soon after birth (women generally defecate shortly ... | [
"It's a combination of a few things. Generally our first exposure is via the birth canal during birth. So yes, this means babies born via C section start out different than vaginally born babies. Our next exposure comes from breastfeeding. Breast milk is not sterile. Lastly, we get further exposure from our environ... |
[
"Is it possible to make a machine that creates a medium sized sonic boom/shock wave that would be strong enough to harm a small animal or insect?"
] | [
false
] | [deleted] | [
"Check out the ",
"pistol shrimp",
"!"
] | [
"There's actually a shrimp that does that, as alex mentioned. This can be replicated with a powerful ultrasound transducer. You can also use the same effect to crush a bottle of beer. Google beer cavitation"
] | [
"You know..for science. "
] |
[
"Spacecraft can pick up speed using a planetary gravitational assist, but can they use the Sun speed around the galaxy for a solar gravitational assist?"
] | [
false
] | Since the Sun's orbit around the galaxy is about 220 km/s could they use the Suns motion to help boost speed? | [
"Ok, I was assuming leaving our system and using our sun."
] | [
"The problem is that we start very close to the Sun and move almost at the same speed (relative to the galactic centre) as the Sun to begin with. To really make use of the gravitational assist we'd have to approach the Sun at a velocity that is different to Sun's velocity. It's a bit like trying to use the Earth fo... | [
"No, the entire solar system is already moving at the sun's galactic velocity."
] |
[
"Can gamma decay result in isotopes not present in the sample's chemical formula?"
] | [
false
] | I am analyzing the gamma ray spectra of Autunite ore and am observing an energy peak which corresponds to Titanium (not in the chemical makeup of Autunite), but is also very close (to a lesser extent) to a Calcium isotope. Is this an error in my process or does the physics make this possible? | [
"Are you seeing any other Ti peaks? If the Ti isotope you think it is has more than one major gamma emission and you don't see the others, its not Ti. Are you sure your instrument is calibrated correctly? Can you get a Co60 or Cs137 or some other common check source to check the calibration?",
"Also, here is a ",... | [
"Just because titanium is not in Autunite does not mean there are not small contaminants of it. How did you irradiate the sample? Are you doing NAA or some other method? The key to gamma spec is to know what gamma rays are even possible to see and to make sure the branching ratios for the lines you see make sens... | [
"Gamma decay does not change the atomic number or the mass number of an atom, so no, it can't create different isotopes.",
"How far off the calcium peak is your measured peak?"
] |
[
"Are pacemakers able to adjust their \"heart rate\" based on the exertion of the person they belong to? Do they support a feedback system with the body?"
] | [
false
] | I was thinking about this today, since someone's heart rate fluctuates even as they just stand up, do pacemakers have a way of dealing with such fluctuation? And if they can, to what extent can they support changes in heart rate? Could a pacemaker patient go for a run, or participate in extreme sport, for example? | [
"Pacemakers generally regulate pacing at a lower boundary; this lower boundary is usually set by a cardiologist.",
"Pacemakers do not, however, regulate every heart beat. Aside from other contraindications there is no reason a pacemaker patient cannot run, exercise, or live a normal, healthy life. Their heart rat... | [
"Tons of misinformation in the replies of this thread! The answer is yes- a pacemaker can increase your heart rate with activity. Algorithms on most devices use accelerometers based on motion detection, one company uses impedance readings from the right ventricle to adjust heart rate. Pacemakers are brilliant. If y... | [
"Modern cardiac implants are extremely versatile that way. As a heart failure patient with decent rhythm (but an extremely low ejection fraction,) I opted for an implanted cardiac device primarily for the defibrillator function. After trying the normal pacing routine to restart my heart, it can deliver a jolt dir... |
[
"Is there any shape that's impossible to calculate the area of?"
] | [
false
] | When calculating the area of a weird shape, what you normally do is break it up into easier shapes to work with, like triangles, squares, etc. I'm not aware of any other way you can calculate the area of more irregular shapes. So is it possible to create an irregular shape that is impossible to break up into other sh... | [
"It is not so easy. With the axiom of choice you can make ",
"non-measurable sets",
" for e.g. volumes. You can still assign a volume to them* but you lose all the properties you would expect for a volume, e.g. that the volume of two shapes adds if you put them together.",
"It turns out that areas in the usua... | [
"It is not so easy. With the axiom of choice you can make ",
"non-measurable sets",
" for e.g. volumes. You can still assign a volume to them* but you lose all the properties you would expect for a volume, e.g. that the volume of two shapes adds if you put them together.",
"It turns out that areas in the usua... | [
"When calculating the area of a weird shape, what you normally do is break it up into easier shapes to work with, like triangles, squares, etc. I'm not aware of any other way you can calculate the area of more irregular shapes",
"You have the correct idea, but you can do something slightly different, that would w... |
[
"What happens to a human in a massively strong magnetic field?"
] | [
false
] | Me and my friend were discussing the possibility of launching a person with a magnetic accelerator (railgun?) and started wondering what effects a ridiculously strong magnetic field will have on a human, does the iron in our blood react? Does the nervous system freak out? Help us , you are our only hope! | [
"You can check out ",
"these past posts",
" regarding blood iron in a magnetic field. The short answer is that iron in our blood isn't ferromagnetic, and won't be drawn to a magnet like iron filing would.",
"There can be effects on the nervous system as well - that is the basis behind ",
"transcranial magne... | [
"most MRI machines in hospitals today use a 1.5 T magnet, which is quite strong. Some places do have 3 T magnets though. Humans are generally unaffected in this field strength. For animal research, scientists use 7 T or (up to 11 T, I think) magnets. This improves resolution on the MRI. When a human is put in ... | [
"Wow, I had no idea you could use induction ln the brain, gotta read up on this stuff! ",
"Thanks for the help!"
] |
[
"Is there a maximum theoretical strength that a material can have ?"
] | [
false
] | EDIT : And what about a "pseudo" material made of nano-machines à la Terminator 2 ? | [
"Sort of. Going fairly hypothetical, the speed of sound in a material cannot exceed the speed of light, which puts a constraint on the ratio of the tensile strength to the density. This was relevant in a ",
"paper I read",
" about trying to harvest energy from black holes by lowering a bucket to near the horizo... | [
"The strength of any material depends on the bonds between its constituent particles. The strongest bonds are ionic bonds and their strength is given by the electronegativity of each of their atoms. Strongest bonds occur between alkali metals and halogens. These get stronger with bigger metals and smaller halogens.... | [
"A bit more context for the \"speed of sound in a material cannot exceed the speed of light\": this is a solution to the ",
"scissors paradox",
".",
"TL;DR: Imagine if you have really, really long (AKA light-years long) scissor blades that are infinitely rigid. When you close the scissors, the point of contac... |
[
"How do we measure rises in sea level?"
] | [
false
] | When i hear claims that sea level has risen x percent over the last 100 years, i wonder a) what is the change in sea level relative to, and b) how can we accurately measure something like that over a span of 100 years, when taking into account the precision of the tools used to make measurements that small 100 years ag... | [
"It is important to note that sea level is not one value everywhere around the world. The ",
"geoid",
" (ideal shape of the Earth, defined by a gravitational equipotential surface) differs from the ",
"ellipsoid",
" (best-fitting elliptical shape of the Earth) by about +/- 100 meters (300 feet). The ampli... | [
"This was what I was looking for. Thank you very much!"
] | [
"Keeping track of the sea level along the coast is something that's been important to seaside civilizations as long as they've existed. The rise is typically defined relative to a climatological average over an established period of time (typically a majority of the record)."
] |
[
"How does ethanol in E-diesel reduce tailpipe emissions in vehicles?"
] | [
false
] | Title says it all. | [
"from ",
"ethanol fuel",
" \"The ",
"Clean Air Act",
") requires the addition of ",
"oxygenates",
" to reduce carbon monoxide emissions in the United States.\"",
"An oxygenate is a compound containing oxygen. Ethanol is the possibly best oxygenate for gasoline considering it's cheap and it provides so... | [
"Do you know how more oxygenates reduces carbon dioxide generation (like via what pathway/mechanism)?"
] | [
"I don't think oxygenates reduce carbon dioxide production. If they do it is by replacing carbon with hydrogen. I believe oxygenates reduce carbon monoxide and smog production by increasing the amount of oxygen present, causing the fuel to burn more completely."
] |
[
"Why does the driver's side window and windshield fog up more than the rest of the car even when I haven't been in it in 12-hours?"
] | [
false
] | Every car I've owned has done this. It seems like my lingering humidity would disperse itself evenly throughout the car. My body heat must surely be gone within half an hour. Follow up question: why does this also happen to my driver's side mirror? It's so ridiculously separated from the interior of my car it's ridicul... | [
"Condensation begins to form immediately as the surfaces cool, not just first thing in the morning. For the interior glass surfaces of the car, when you park it at night, the surfaces near you will be much warmer and will immediately form more condensation.",
"For the exterior surfaces like the side mirror, it co... | [
"A lot of cars come with anti-condensation coating on the windows. It's possible to wipe this stuff off. Even rolling down your windows will do it eventually. I suspect that you roll your driver's side window down to wipe the mirror. This would eventually (maybe quickly) remove the coating from both. "
] | [
"When I'm not there."
] |
[
"Does the formation of bonds mean a chemical reaction has occurred?"
] | [
false
] | I was reading about how the components in a mixture haven't reacted with each other so can be separated via boiling which got me wondering what does it mean for them to react with each other. I've always thought of it as bonds forming but this doesn't seem true here as bonds exist between the atoms in the mixture so ho... | [
"Bonds forming is an indication of a chemical reaction. A mixture does not create new bonds or break bonds. Sugar, for example, just mixes in with water. Each sugar molecule is surrounded by water molecules and becomes an aqueous solution. These are not “bonds” but rather intermolecular forces that hold the mixture... | [
"I'd like to elaborate on that a bit regarding some important types of bonds and molecular interactions. I'll try to simplify as much as I can and proceed from weakest to strongest in terms of bonding strength.",
"\nThe weakest of the underlying forces are Van-der-Waals-forces. They occur between any kind of atom... | [
"Metallurgy and inorganic chemistry quickly blends into condensed matter physics. ",
"Metals and semiconductors will arrange themselves in specific crystal structures that depend on their electron valence. In the crystal the outermost electrons tend to get shared collectively. What that looks like is the energy ... |
[
"How long does it take for evolution to change one species into two that aren't sexually compatible?"
] | [
false
] | More specifically, how many generations would North Korea have to remain isolated in order for them to not be able to reproduce with people from the rest of the world? | [
"Eugenics really doesn't have anything to do with this question in my opinion."
] | [
"The genetic factors which prevent two species from interbreeding are thought to accumulate either by chance or as a byproduct of selection on other traits. For any two species to develop a genetic barrier to reproduction, both species have to have mutations evolve which are incompatible with each other -- all fair... | [
"There are far too many variables to make a blanket statement about a length of time and as far as the specific question you will only get extremely basic guesswork."
] |
[
"What is superconductivity?"
] | [
false
] | [deleted] | [
"Please go spend thirty minutes on Wikipedia and come back with some more specific questions. AskScience is here to help with things that aren't trivial to look up. As a starting point, you could look into the Ginzburg-landau equations, which provide a relatively simple model of superconductivity near the critical ... | [
"I really like how ",
"this article",
" approaches it. It's in true ELI5 spirit, I think."
] | [
"Okay. Thank you!"
] |
[
"Theoretically how many write cycles can a SSD (solid state drive) go through before all its transistors break down?"
] | [
false
] | null | [
"Any individual cell in a Flash memory device will wear out after an essentially random number of write/erase cycles. A manufacturer will guarantee a minimum number of cycles, and that typically involves including some spare blocks and re-mapping bad blocks which fail before the minimum number of cycles. How many c... | [
"Dont flash storages last 100k to 1m times?\n(Side fact: hdd platters last around 10 billion cycles)"
] | [
"Yes, the raw flash memories will have rewrite endurance of 100k to 1M times. But there are some unique issues with using Flash in an SSD environment. One is what they call \"write amplification\". At the application level, you can write a single byte to a file. That's buffered up by the operating system to updates... |
[
"If being cold does not lead to colds then why do we get ill after being cold?"
] | [
false
] | I lived up north as a kid and one thing most parents were concerned about was their kids getting cold or what's worse, getting their feet wet while playing in snow etc. I fell through the ice a number of times and by the time I walked home I was drenched and freezing. My parents would stick me in hot bath and give me h... | [
"Why does everyone go down with pneumonia after being stuck in snow or falling through ice?",
"You are making some pretty strong claims here, and I really don't think they're true.",
"I can't speak to your personal experience with falling through the ice, but the \"common knowledge\" that exposure to the cold c... | [
"Hmm. Well, I guess there's probably a distinction to be drawn between going out and playing in the snow as a child and like, falling through the ice and becoming severely hypothermic. I might imagine that becoming hypothermic could seriously weaken your immune system for some period of time, making you far more su... | [
"One theory is that cold air is drier than warm air, which dries the mucus membranes which is important for trapping foreign bodies and airborne pathogens."
] |
[
"Why is Gravity so much weaker than Electromagnetism?"
] | [
false
] | Now, I don't mean to ask this based on our current theories, because as far as I know, they don't say so. What I really want to ask is what our proposed theories of quantum gravity, like string theory and loop quantum gravity, say about the disparity in strength between the two forces. Is there any indication that our ... | [
"The other three forces besides gravity (electromagnetism, the weak nuclear force, and the strong nuclear force) are all a trillion trillion trillion times stronger than the gravitational force. Scientists don't know why yet, but they're doing research that may provide an answer soon.",
"So far the best answers a... | [
"Science patch 89.0 is slated for release sometime this November, just in time for the holiday shopping season."
] | [
"http://www.youtube.com/watch?v=wMFPe-DwULM",
"Just watch Feynman's response to the question \"Why?\""
] |
[
"What is the meaning of the wave-vectors?"
] | [
false
] | I'm reading a paper by Belov, Tretyakov and Viitanen. In this paper they discuss the dispersion properties of a wave travelling through a parallel wire medium. [ ] In the paper they start by solving for the electric and magnetic field in this infinite periodic structure as a result of current amplitudes that has a pl... | [
"A wavenumber (the magnitude of a wavevector) is the \"spatial frequency\" of the wave, just like the frequency is the \"temporal frequency\". It measures how rapidly in space the wave oscillates. Unlike temporal frequency, you need a wavevector to fully describe the spatial frequency of the wave because there are ... | [
"I know that much, the confusion was over the different simulatious definitions in that paper."
] | [
"In electromagnetic theory, it's not uncommon to specify both a free space wavenumber as well as a bounded wavenumber inside the medium (I was instantly reminded of the Waveguide/Cavity Resonators section from ",
"Cheng",
"). I think you got that far in your opening paragraph.",
"On page 1156, it defines k as... |
[
"Why do our limbs tingle or get numb when they \"Fall asleep\"? Also why does it hurt? And what happens inside the body when this happens ?"
] | [
false
] | null | [
"Your brain freaks out when it stops getting signals from your leg. The pain may be there to alert you that something is not right, or simply because of nerve confusion. A similar thing happens with amputees who suffer from phantom limb syndrome, which often manifests with severe phantom pains in the missing \"limb... | [
"Yes, you can move it. This is how modern prosthetics work. It detects electrical currents in muscles."
] | [
"He also asks why that hurts. If they're not firing, please describe the origin of this pain "
] |
[
"How deep or shallow can the sand be in a desert?"
] | [
false
] | I mean not standing on a dune, just standing on fairly level sand at whatever average altitude from sea level any given desert is, how far down can the sand go? Can it be very deep or just a few inches before you hit different material? Does it vary greatly from one desert to another? | [
"How deep can it be?",
"Very deep. Over half a mile, perhaps as much as mile under very special circumstances. ",
"The thickness of sand under the dunes is going to depend on the length of time that deposition was greater than erosion. In a desert, deposition = sand being blown in, and erosion=sand being blown ... | [
"Seriously, thank you for a fantastic answer."
] | [
"Another party of your question regards variance. They can vary a lot, considering there are some high desert regions without sand at all (a good example of this would be Joshua tree national Park in California)."
] |
[
"Is the water used to cool spent nuclear fuel rods radioactively contaminated? If yes, what is happening with it after it gets exchanged with fresh water?"
] | [
false
] | I was not able to find any useful resource on this topic, thought someone here could help me :) | [
"Since I've been paged. ",
"I'm a current senior reactor operator at a US boiling water reactor.\nI'm going to be talking from a boiling water reactor perspective, but most of this is applicable to any primary coolant system. Also, heavy water reactors will have some different answers as they have a lot of tritiu... | [
"The tsunami water did not get into the reactor coolant system or spent fuel pool. It flooded the electrical equipment (generators, switchgear, breakers) in the basement. ",
"The reactor is a sealed system at over 1000 psig or pressure. Water isn’t going to get in. The spent fuel pools at those units are on the u... | [
"Thanks!"
] |
[
"Where two oceans meet - is this real?"
] | [
false
] | with the following description: Where two oceans meet... but do not mix! INCREDIBLE AND SIMPLY MIND-BLOWING!!! These two bodies of water were merging in the middle of The Gulf of Alaska and there was a foam developing only at their junction. It is a result of the melting glaciers being composed of fresh water and the o... | [
"Ron_Leflore is correct. I am that photographer and it was very real. He posted the links to the many photos I took as the ship passed through that area. The lighter color is from the sediment in the water based on what I have researched and saw."
] | [
"So we can start with the first bit: The segregation of bodies of water that have a high property contrast (as claimed by the image) definitely occurs in nature. It will always happen at some point below the surface, at 100-200 m (hence why it is usually pretty tricky for the upper ocean to mix with the deep ocean)... | [
"As a note of possible interest; submarines will use these thermocline boundaries to hide from vessels above or below them as the layer of separation is acoustically insulating as well (noise from engines won't penetrate the layer boundary and it reduces the efficacy of active sonar). Sometimes sub-drivers will r... |
[
"Is blackbody radiation continuous or discrete?"
] | [
false
] | null | [
"The black body spectrum is continuous over all energies."
] | [
"Thanks - so if I'm understanding more or less correctly, blackbody radiation is continuous, but superimposed on that are a vast number of spectral lines (most negligible), which can bias the continuous spectrum to specific energies based on the composition of the star? But other processes that produce photons don'... | [
"The black body spectrum is continuous, but spectral absorption/emission lines are (quasi-)discrete. So what you see is the composition of a continuous black body spectrum, plus discrete lines."
] |
[
"How do Neural Processing Units (NPUs) work in contrast to conventional CPUs?"
] | [
false
] | I refer to this article about analog/neural computing: According to the author there is not much room to further increase transistor density on CPUs (or number of cores) in order to get more computing power on a sustainable level. A possible solution would be to use Neural Processing Units (NPUs) for certain types of c... | [
"Well just based on the article ",
"http://www.cc.gatech.edu/~hesmaeil/doc/paper/2012-micro-npu.pdf",
" it would seem that an NPU contains some processing engines, each of which are assigned neurons which they then perform computations for. The idea is that you can create neural network models to simulate and s... | [
"As a researcher in computer architecture, I'd just like to add a note of caution. This is cutting-edge research in a fairly new (at least \"born again\") field of architecture. That means that the final potential of these ideas is unknown -- it could revolutionize the world (unlikely, IMO), it could end up being u... | [
"Neural Nets are really good at some things that are rather difficult otherwise, such as image recognition or audio signal processing. They work by simulating \"layers\" of neurons, and training these neurons in the same way as in a brain. However, most neural net implementations at the moment take either one CPU c... |
[
"Could an creature have both an endo and exoskeleton? Do any?"
] | [
false
] | null | [
"As far as i understand it, no creatures have both as it is simply not required. One of the basic functions of a skeleton (exo or endo) is simply to provide structural support for the creature, so it can move. If it has a exoskeleton it has no need of an endoskeleton, and vice versa. ",
"However i'm not sure if y... | [
"I'm obviously taking huge liberty with interpretation of definitions here, which I understand you decided to avoid, but I'd still like to nominate turtles and tortoises. \nRegular endoskeleton in limbs and endoskeleton (almost) gone exo around the main body. Most of them have a layer of horn on the outside of the ... | [
"Neither antlers nor horns provide structural support for the body. A tortoise shell does."
] |
[
"Is all animal muscle essentially the same, at the cellular level?"
] | [
false
] | I'm just wondering if there are animals out there (no matter how far removed from humans) which have significantly different muscle cells. Maybe ones that have a much higher power:weight ratio, or ones that are more energy efficient. Or do all muscle cells require about the same amount of energy and muscle mass to do ... | [
"There is actually a pretty significant difference in muscle throughout the animal kingdom. They all contain the same basic layout with smooth, skeletal and cardiac, with intercalated discs and multinucleated, high ratios of mitochondria. But if you look at muscles in marine mammals they have a much larger amount o... | [
"That's not really a difference though. Humans have that too. Take an endurance runner vs a sprinter and the same discrepancy will be there, even amongst the same species. ",
"Chickens have higher glycolytic muscle ('white meat'), canines have higher oxidative muscle (dark meat), but it's all the same at the b... | [
"Is there any logic behind the notion that fish muscle doesn't count as 'meat'?",
"(i.e. is it fundamentally different from mammal meat?)"
] |
[
"Concerning the lifespan of hunter-gatherers:"
] | [
false
] | suggests that they lived almost as long as modern people; conventional wisdom has them dying at 30. Is there something wrong with that study, or is the short-lived hunter gatherer just a myth? | [
"There are two aspects to this:",
"(1) A lot of people died in infancy, childhood, early adulthood, or middle age. This drives down the ",
" age. ",
"(2) If you didn't die young, you might live to be old. There were still old people, it's just that a much higher percentage of people didn't live to be old... | [
"Those critics should give a look-see at Jared Diamond's essay ",
"The Worst Mistake in the History of the Human Race"
] | [
"People seemed to think that paleolithic people died of heart disease, diabetes, and other diet-induced diseases.",
"Well, I think the argument is confusing to most people. With regard to the paleo diet, arguments that \"they died when they were 30\" usually forget that they didn't die that young due to diet, but... |
[
"How come we have rabies vaccines for animals yet none for humans?"
] | [
false
] | null | [
"We do have a rabies vaccine for humans.",
"https://www.cdc.gov/rabies/specific_groups/travelers/pre-exposure_vaccinations.html"
] | [
"As mrrp noted, the vaccine does exist.",
"The reason it is not widely produced and given is, in my uneducated opinion, probably due to economics.",
"The vaccine requires frequent (annual-ish) boosters to maintain effectiveness. It is largely not an inter-human communicable disease, and the relative risk if bri... | [
"I don't think the insult was necessary.",
"Additionally, bring vaccinated is not to stop transmission ",
" the recipient, it's to inhibit transmission ",
" the recipient.",
"Additionally, while not the greatest of sources, Wikipedia says human bites can transmit rabies, so you're wrong in essentially every... |
[
"Speed of light question."
] | [
false
] | Maybe this is a retarded question but here goes. Ok so the the speed of light = 299 792 458 meters a second. But it has been shown with atomic clock experiments that time passes slower in higher gravity. So if time is not a "constant" then how can it be that light speed is fixed. surely it would also be relitive to gra... | [
"Speed of light is \"fixed\" in the sense that no matter where, when and how you measure it, you always get the exact same result. The Universe is just built like that. Everything else can change, but not this number.",
"EDIT: You seem to assume that space and/or time are somehow \"more fundamental\" than the spe... | [
"That's not what I said. Pay attention.",
"I said (well, Einstein did, not me) that space and time are not absolute, the way they were in Newton's model. In relativity, the speed of light is absolute; space and time are relative.",
"That doesn't mean space and time do not exist. That doesn't mean \"I'm not even... | [
"Time is slow in a different frame ",
" the speed of light is fixed."
] |
[
"Do plants develop cancer?"
] | [
false
] | null | [
"From a great ",
"source",
":",
"Plants CAN get cancer of sorts. However, because of some of the differences between animals and plants, plant cancers behave differently to those in animals.",
"First a definition: What is cancer? Well, in animals, cancer can be defined as a disease where the cells in part o... | [
"Thank you very much kind sir. I believe that pretty much sums up my question."
] | [
"A little bit more information, but one of the common bacteria that cause crown gall disease in some plants is Agrobacterium tumefaciens. The mode of transfer of the DNA from tumefaciens into the tree or plant is now a common way to do genetic engineering in plants."
] |
[
"How does electric shock kill you?"
] | [
false
] | [deleted] | [
"It depends how much amperage flows through you. At around 17mA it starts to affect the elctrical signals which control muscles, which can cause death through respiratory or heart problems as the normal operation gets screwed up. At 100mA above it starts to damage the nervous system, and can cause harm to the conn... | [
"It can cook you if the amps are high enough. Basically when elections enter the body they look for the path of least resistants. We happen to have a nervous system that is made to carry electrical signals to all parts of the body. So the voltage will run rampant confusing everything. An amp at the heart can stop ... | [
"There are two ways an electric shock can kill you: stopping your heart and cooking your flesh.",
"Stopping the heart requires contracting part of the heart (which is a system of muscles rather than a single one) such that the muscles begin to beat out of sync. This requires as little current as 30mA AC or 300mA ... |
[
"Why is eating raw animals more likely to result in infection than eating raw plants?"
] | [
false
] | [deleted] | [
"Plants have secondary metabolites that protect them from bacteria. Those are still active even when the fruits or vegetables sit on your counter. Animals depend on their immune system for that, and that stops working after death, so meat spoils faster and grows bacteria. Also, meat can contain infectious parasites... | [
"Yeah. Secondary metabolites are substances created by their metabolism which aren't directly related to the energy metabolism, growth or reproduction. As a common example, all those flavour compounds that make spices, well, spicy are secondary metabolites."
] | [
"Yeah. Secondary metabolites are substances created by their metabolism which aren't directly related to the energy metabolism, growth or reproduction. As a common example, all those flavour compounds that make spices, well, spicy are secondary metabolites."
] |
[
"Do coronal mass ejections from solar flares cause the sun to move?"
] | [
false
] | I mean in an action and reaction way, does the plasma ejection make the sun move a little to the opposite side? Is it enough to cause any disturbance on the orbits of the planets? | [
"You know of Newton's 3rd law, so you can answer the first question yourself: for sure. ",
"For the second, you would need to compare the ",
"mass of a CME, m1",
" with the ",
"mass of the sun, m2",
". The mass ratio m2/m1 is on the order of 10",
" / 10",
" = 10",
" from which you can deduce -- v... | [
"Yes to an insignificant degree. \nSimilar to how a spaceship would combust jet fuel and shoot out exhaust at a high velocity. The exhaust has mass and this body is “pushing back” on the rocket .\nThe solar flare, however, is not be designed to optimize exhaust concentration. Additionally, the mass ratio of the sun... | [
"Just a slight clarification: coronal mass ejections are not \"from\" solar flares. For a long time the two were thought to be inextricably linked, but we've since learned that while the two often occur at the same time, this is not a necessity: it is possible to have solar flares without CMEs, and vice versa."
] |
[
"How fast would a vertical platform have to accelerate for you be able to stand on it sideways?"
] | [
false
] | null | [
"You need the force of friction to be equal and opposite to gravity, so μmA = mg, where μ is the coefficient of static friction, A is the acceleration of the platform, and m is your mass. Your mass cancels, and you just have A = g/μ."
] | [
"In addition to the nice mathematical answers given by others here, you can think about it intuitively as if you were standing on a sloped surface, whose slope is the ratio of gravity vs horizontal acceleration. For example, one g of horizontal acceleration would make it seem like you were standing on a very steep ... | [
"Back in the olden days...\nSix Flags amusement park used to have a ride that was essentially a spinning barrel with rubber covered walls. The riders would stand up next to the walls and it would start revolving up to speed. Then the floor would drop down and you would be stuck to the wall. Some people would try to... |
[
"Is it possible to map the genome of 2-3 generations of homo sapiens (typical humans) and find the exact mutations between them?"
] | [
false
] | Has anyone already done this? If yes, a source would be great; if no, then why not? It would be a very useful fact and a powerful demonstration of both the wonders of modern science as well as the underlying mechanism behind evolution to those who deny the theory. | [
"Aren't we working on mapping the purposes of each gene? I know that there is a large project dedicated to the complete understanding of E. Coli, but I'm sure the human genome is much more complicated.",
"But even so, wont having the information eventually be useful? Science for science sake I suppose. "
] | [
"Yes it is possible, but this isn't practical. It's expensive and we don't know what a lot of our genome does. It's only practical if you know exactly what mutations in the identified genes that you are looking for."
] | [
"We are working on it, but far from knowing everything. Perhaps eventually useful, but currently not practical - it's a scarce world"
] |
[
"Can allergies affect mood and behaviour?"
] | [
false
] | [deleted] | [
"I wasn't aware the serotonin circulation of the gut was associated with the concentration of serotonin in CNS synaptic clefts. Do you have a citation? A brief literature search doesn't show any clear leads..."
] | [
"Is it possible for allergies to affect mood",
"Let's take a genuine, known food \"allergy\": celiac disease. These folks have serious malnutrition problems and can suffer greatly. Depression is predictably common. Expanding a bit to the broader class of autoimmune disease, generally, you can again predict depres... | [
"well... I suppose possibly less fat would lead to less estrogen, and possibly cessation of menstruation in women, with commensurate effects on LH and FSH, but I'm not sure those would affect mood. And at that point, you're back in the realm of serious malnutrition. But there's decent evidence for a relationship be... |
[
"When does a bullet reach its maximum velocity?"
] | [
false
] | I was wasting my time on youtube watching gun videos and this got me thinking. The bullet has to reach Vmax from standstill in some time, then is slows down due to air drag. It should be somewhere in the barrell, but is there a way to know when and where? Also is this related to the force the gun kicks back with? | [
"Probably right as it leaves the barrel. For many cartridges, firing the same bullet from a longer barrel will result in higher velocity because it doesn't \"waste\" as much of the gas expansion. Imagine a very snub nosed revolver: there's a huge flash of fire out the barrel ",
" the bullet, and all that gas exp... | [
"Yes.",
"Think of it this way. The bullet acts as a plug and prevents gases from exiting the barrel. The instant it leaves the barrel, all the pressurized gases trapped behind it are also released. That's the flash.",
"For the same bore, a longer barrel does two things:",
"For as long as the bullet is in the ... | [
"Generally, the muzzel velocity (when the bullet leaves the barrel) is the Vmax for a bullet from a gun. This is due to the loss of propulsion and the overtaking of friction and drag. No more push, just slow-down after that."
] |
[
"Is Lead Nitride an actual compound?"
] | [
false
] | Hi there, I'm doing an ERT on the decomposition of Lead Nitrate. One of my possible products is Lead Nitride (Pb3N2) - from what I can tell, it is not an actual substance; on the contrary, however, there seems to be no evidence I can find disproving it's existence. Is there anyone who would consider themselves 'experts... | [
"Do you have a source? Perhaps a mention of where it's used or how it's synthesized?",
"A brief google search yielded nothing for me."
] | [
"This handbook",
", on page 1800 mentions that it is very unstable. It does not mention its preparation, but does provide further references, if you are interested. ",
"Warning - links to a large pdf file."
] | [
"http://iopscience.iop.org/1402-4896/2010/T139/014073",
"They say it doesn't exist."
] |
[
"What is this little creature?"
] | [
false
] | null | [
"You might try ",
"/r/whatsthisbug",
"."
] | [
"Will do, thanks"
] | [
"I'll guess it's a hawkmoth.",
"[edit] the pupa.",
"https://www.google.com/search?q=Hawk+moths+pupa&hl=en&tbm=isch"
] |
[
"Is it true that we predominantly breathe through only one nostril at any given time?"
] | [
false
] | Today there was an interview with German journalist Jessica Braun in the newspaper, mostly about her book "Atmen: Wie die einfachste Sache der Welt unser Leben verändert" ("Breathing: How the simplest thing in the world changes our lives"). I haven't read the book, but according to the interview the book at one point s... | [
"It doesn’t completely shut down one side at a time, but it does slow air down. The purpose of this is due to smell. Some odors/smells cannot be detected unless the air velocity is slowed down. So your nostrils will alternate between dilation and constriction. One side for faster air, one side for slower."
] | [
"Am a worm biologist, not a human biologist, so take this with a grain of salt.\nTo my knowledge, it's true. One nostril is kept partially shut by dilation of the blood vessels. This is why when you're sick one nostril usually feels completely shut while the other one is fine. The inflamation from being sick, on to... | [
"Thanks!"
] |
[
"How did amber encapsulations happen?"
] | [
false
] | [deleted] | [
"It probably landed on this poor guy or he fell into it. The weight of the Amber is irrelevant, once it's encapsulated the antenna have plenty of time to spring back before the Amber hardens. Bugs die of oxygen deprevation relatively quickly. Amber is not this pretty in nature, this was almost definitely cut/polish... | [
"There was a cut on a tree that was \"bleeding\" resin. You can spot those e.g. on cherry tries. They are sticky and grow very slowly forming a round droplet that likely won't fall down but will harden still on a tree branch.",
"The mantis went on top of such droplet and got stuck, surface tension sucked the mant... | [
"Resin, not sap. Resin is the viscous stuff that oozes over damaged parts of a tree and can become amber if buried so that it is subject to heat and pressure for a long time. ",
"Sap is a milky white sugar-water substance used to transport carbohydrates and nutrients through the tree. "
] |
[
"What are these creatures in my micrographs?"
] | [
false
] | [deleted] | [
"Hah, I could try, but it might take a while... starting with learning what that means."
] | [
"It looks like some sort of filamentous cyanobacteria (blue-green algae) to me (just because they're in a filament, tiny and look like some pictures sorta I've seen). Could you sequence its 16S rRNA gene by chance? "
] | [
"I would have thought them for cocci, but I can't seem to find an SEM with those protrusions. Closest SEM I found, in fact, was for a ",
"leukocyte",
", but that doesn't make much sense to me."
] |
[
"Why does the outline, or drawing on a fogged mirror or window stay there for so long? Even after the condensation has gone and come back multiple times?"
] | [
false
] | Ok so I was staying the night at a friends house about six months ago when I decided to draw a music clef on the bathroom mirror after a steamy shower. I tried to wipe it off, but it just reappeared. Fast forward six months and I come back, take a shower, and boom the music staff is still in the same spot. I wipe it an... | [
"Your finger leaves a coating of oil on the surface of the glass. This coating affects how water sticks to the surface. The oil will change the contact angle between the droplets and the surface, which will make the oil-coated and clean areas look different. (There might be other effects contributing to the diff... | [
"[Mind you, everything following is hypothesis of mine, based on quick research. Do not assume anything following as peer-reviewed, unless otherwise stated.]",
"Almost the entirety of your body are covered in sebacceus glands, which produces a matter called ",
", ",
"which Wikipedia describes as 'oily' or 'wa... | [
"This is exactly right. As a way of testing this, try doing this experiment using something that won't leave a residue (a fork perhaps)?"
] |
[
"What does the bend at the end of a plane's wings do?"
] | [
false
] | null | [
"So in simple terms a plane flies by having low pressure on top of the wing and high pressure on bottom of the wing. ",
"But at the tip the air moves upfrom the bottom to the top (high pressure to low pressure) in sort of a circular motion (when viewed from the back of the plane) these are called vortices (vortex... | [
"https://www.reddit.com/r/askscience/comments/93rwzw/why_is_the_tip_of_an_airplane_wing_bent_upwards/"
] | [
"If you don't put the 'bendy bit' at thend, then the last meter or so of the wing will not contribute to the lift, because the air rotates around it, as you said. Then the plane needs a bit more parking space, and is in general a bit harder to handle on airports. This is the main reason why they tilt the last part... |
[
"Did hissing evolve independently numerous times, or was there an ancient hissing ancestor?"
] | [
false
] | I've noticed that a lot of animals perform a hissing action when they feel threatened, involving opening the mouth and expelling air: Red-eared sliders (semi-aquatic turtle), several species of goose, domestic cats, possums, numerous insect species.... did these species all develop this behavior independently or how? | [
"You probably have a combination of factors at play here.",
"First is biomechanical. Passing air through a confined hole will usually produce a hissing noise, just by the nature of things. So any sharp inhalation or exhalation might produce a hiss....it's about as easy to make sound as you can get. So easy it... | [
"Although you make a lot of good points, it seems like, at the very least, a coincidence that hissing, of all things, would be so common, and behaviors like the cat's broad-side facing to make itself look bigger would almost make more sense to be cross-species. "
] | [
"broad side facing and compression of the body to make it look bigger is actually really common too. Even, eg, chameleons do it (while hissing, in fact)"
] |
[
"Water is more dense as a liquid than as a solid. Is there anything about it on the molecular level that would let us predict this behavior?"
] | [
false
] | null | [
"Hydrogen bonding! In a solid state, the average kinetic energy of water molecules is low enough that hydrogen bonding can happen. This creates a highly ordered crystalline structure with lots of space between molecules. In liquid water, however, the kinetic energies of the molecules overcome the hydrogen bonding e... | [
"I should add its not just hydrogen bonds, but the fact that water forms 4 hydrogen bonds which forces it into that spread out configuration in order to maintain all 4 bonds. Which in turn gives the lower density.",
"Other molecules such as Ethanol also have hydrogen bonds, but they can pack much closer together... | [
"The enthalpy of a hydrogen bond in water is approximately 21 kJ/mol. If the enthalpy of the bulk fluid exceeds this by a large enough amount, hydrogen bonds will not be able to stably form. Since solid water is colder than liquid water, it has lower enthalpy. Thus hydrogen bonding can happen more frequently and mo... |
[
"Is there a psychological reason for why people derive pleasure from destroying things?"
] | [
false
] | For example, go to the beach and watch someone walk up to a sand castle, pause, and then stomp it to oblivion, for absolutely no reason whatsoever. Same goes with other easily accessible work of art, people just seem to enjoy ruining anything that has a defined and organized structure. Why is that? | [
"Several explanations... people learn to laugh at pain in general, it helps them cope. For example, you fall down stairs, it hurts terribly, and you laugh it off... that behavior is getting rewarded, so applied to the general destruction of things it brings pleasure. Another explanation is that all humans have a de... | [
"I would say because its a relief from the pressures of society we have placed on ourselves....\nAlso that, destroying other peoples gives a feeling of dominance, and we humans like to feel superior, if anything but our entire history has said anything..."
] | [
"Interesting question. Young children do this, some do it a lot. Playing with a toy car and then stop, and just runs it of the edge of the table or down the stairs and laughs, sometimes what I would describe as, maniacally or glee, as it crashes and breaks."
] |
[
"Where can I find the \"full\" Big Bang Theory ?"
] | [
false
] | Is there a full article, or full document with the theory ? If so, please post it on the comments. Thanks in advance. | [
"The Big Bang isn't a theory on its own. It's a consequence of the two major pillars of modern physics: ",
"general relativity",
" (GR), which describes spacetime and gravity, and the ",
"standard model",
" (SM), which describes all the particles and forces (besides gravity) that we know of which live in th... | [
"A minute after the Big Bang, the Universe was mostly very high energy photons, with some neutrinos, dark matter, protons, neutrons, and electrons running around as well, all mixing and expanding, and still very uniform - at this point, structure hadn't yet started to grow from small non-uniformities, so every plac... | [
"Well, we ",
" have observations testing different eras of the history of the Universe. In the case of a few minutes after the Big Bang, the production of light elements agrees very precisely with what we observe. Theory predicted many decades ago that the Universe produced about 25% as much helium as it did hydr... |
[
"Is it possible to make Aurora Borealis in a lab?"
] | [
false
] | If we made a strong magnetic field and made electrons collide with the field, would that create Aurora Borealis? If not, how would we do it? | [
"I don't understand the question. The northern lights are simply excited electrons returning to their lowest energy level and emitting this change as light after being excited by other traveling electrons. A neon sign basically does this. "
] | [
"Well I guess I more or less did this in a 2nd year lab. A filament was used to emit electrons in a glass bulb filled with mercury gas. The bulb was inside of a large coil with current passing through it. The coil created a more or less inform magnetic field that would cause the electrons to flow in a ring through ... | [
"the working principle for the cloud chamber is not really related to aurorae."
] |
[
"What is energy?"
] | [
false
] | I understand that energy is essentially the ability or potential to do work and it has various forms, kinetic, thermal, radiant, nuclear, etc. I don't understand what it is though. It can not be created or destroyed but merely changes form. Is it substance or an aspect of matter? I don't understand. | [
"There's really no satisfying definition beyond \"the quantity that is conserved over time.\" This may sound arbitrary and ad hoc but it emerges from this deep mathematical principal called Noether's theorem that states that for each symmetry (in this case, staying the same while moving forward or backwards in time... | [
"One small correction, more like \"the quantity that is conserved in a system with time translation symmetry\""
] | [
"Nobody can explain it better than Feynman: ",
"http://www.feynmanlectures.caltech.edu/I_04.html#Ch4-S1"
] |
[
"Why is it common to have a stroke when you have a heart attack?"
] | [
false
] | [deleted] | [
"Medic here. A lot of the answers below are not entirely complete. Hopefully this helps:",
"A heart attack, no matter the underlying cause, puts you at high risk of stroke in the acute setting for multiple reasons. We can consider those reasons in terms of ",
", a cool and easily applicable bit of pathology. Th... | [
"Just to be clear, not all 3 factors (more commonly termed: Stasis of blood, endothelial injury, and a hypercoaguable state) of Virchow's Triad need to be present in order to form a clot. As with most risk factors in medicine, the more factors you have, the more likely an event will occur. However, you can definite... | [
"Heart pumps blood into the aorta, and it is at the origin of the aorta where your coronary arteries are. Your svc and IVC are veins, which carry the majority of the blood from your systemic circulation to the heart, then lungs, etc. you may want to refresh some of your anatomy."
] |
[
"Where is dark matter theoretically?"
] | [
false
] | I know that most of our universe is mostly made up of dark matter and dark energy. But where is this energy/matter (literally speaking) is it all around us and we just can’t sense it without tools because it’s not useful to our immediate survival? Or is it floating around the universe and it’s just pure chance that the... | [
" and ",
" are 2 different, unrelated hypotheses. They only share the \"Dark\" moniker because neither of them interact with (absorb or emit) light but, more relevantly, we don't know what they are. You could call them \"Mysterious Matter\" and \"Mysterious Energy\" instead. Indeed, ",
" and ",
" are arguably... | [
"But like is dark matter all around us and just not detectible by human senses",
"Very likely, yes. Dark matter doesn't interact much with anything, so you have individual particles just flying through the galaxies. The most popular models have particles everywhere in the galaxy - some of them are flying through ... | [
"how do we know that we can set up devices that would detect the interaction between DM particles and known, proven particles?",
"We don't. What we can do is set up experiments to detect certain types of interactions, that would happen if dark matter is composed of particles of a certain, assumed form. For exampl... |
[
"Why are some viral infections (eg. measles) once in a lifetime, with no mutations occurring that could bypass the immune response, while SARS-CoV-2 is developing potential immune system escape mutations left and right?"
] | [
false
] | null | [
"It depends on how much change the part of the virus that antibodies latch on to can stand. In this paper ",
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4997578/",
" they investigate that for measles. Apparently the pieces that our antibodies can latch onto don't change enough to fool the antibodies. The piec... | [
"There's a few reasons why. Measles is quite highly vaccinated against in the modern day. The vaccination prevents the spread of the infection to a new host, which is required for the virus to survive, mutate and propagate. If it cannot reach a new host, it will die out.",
"SARS-CoV-2 had no existing vaccine, all... | [
"The champion of this method is probably the hepatitis C virus. It's exterior proteins can still work after mutating so much that this is it's main strategy. You get infected by a few viruses but those viruses mutate in your body that they generate thousands of variants inside your body in just a month. From that p... |
[
"In your field what breakthroughs are expected in the next 10 years that will change our lives?"
] | [
false
] | null | [
"Most of the research in mathematics doesn't really have the potential to \"change lives\" on an individual level (except perhaps in math education).",
"The rule of thumb for math is that about 50 years after we publish our research, some engineer finds a use for it and gets more grant money for it than we could ... | [
"Few scientists are willing to put their neck out and predict 'breakthroughs', for the simple reason that breakthroughs are often unpredictable chance occurances. It's quite often a little side observation in an unrelated experiment which leads to these things. Not something you want to bet money on. We might inst... | [
"Perhaps not in the next ten years, but these are some of the most importance unsolved questions in math and astronomy that we are certainly ",
" for a breakthrough with.",
"In mathematics:",
"In astronomy:",
"In my particular field:"
] |
[
"What determines which copy of a gene will be the active, dominant one?"
] | [
false
] | We receive one copy of our genes from each. If one copy is mutated, what determines which copy will be the dominant one? And is a mutated recessive gene completely inactive, or can it still affect how the body functions? | [
"Genetic material does not really fall into dominant and recessive categories. Those categories are used for the way a trait is inherited. The idea of \"genes\" came before our understanding of the molecular mechanisms for inheritance and thus a lot of language in common usage is not very precise. When scientists t... | [
"I was imagining an answer that would include terms like haplosufficient or haploinsufficient with regards to dominant vs recessive alleles. Does that parlance not apply to this kind of question? I thought it made great sense to me in the sense that one allele would be mutant, and then the wild type allele either w... | [
"I was not previously familiar with those terms, but they seem to be straightforward. Here haplosufficient or insufficient would apply to loss-of-function mutations. Even then, while in simple cases you can see how a haplosufficient trait may be more likely to be dominant, it is not necessarily related. Two haplosu... |
[
"What happens to electricity in a cable when it is cut?"
] | [
false
] | [deleted] | [
"A good way of thinking about electricity is 'movement'. If you envision a cable as a tunnel which cars are passing through, and you collapse the tunnel, the cars stop. The movement - the electricity - vanishes. ",
"There are still cars in the tunnel - meaning, still electrons in the wire. But they're not passing... | [
"The electric potential. Now we need to think of our tunnel as being built on a hill. The cars were in neutral, and they start rolling downhill (to lower potential) again. "
] | [
"That was a very good explanation. What actually causes the cars to start moving again once the \"tunnel\" is repaired? Why don't all electrons move once grounded? Hopefully this makes sense... "
] |
[
"Why does Ritalin now show up on a hair drug test?"
] | [
false
] | null | [
"Yes, I meant \"not\". I apologize. I have read that it can cause false positives for amphetamine or cocaine, but this is a rare occurence. "
] | [
"Yes, I meant \"not\". I apologize. I have read that it can cause false positives for amphetamine or cocaine, but this is a rare occurence. "
] | [
"Yes, it seems a lot of people tend to associate Ritalin with the amphetamine category since it is used essentially for the same purpose as Adderall, which is actually an amphetamine. "
] |
[
"What scientific evidence, if any, exists to support the claim that some races of dogs are naturally more aggressive?"
] | [
false
] | In Denmark, some dog races are banned for breeding on grounds that they are "fighting dogs" and therefore much more aggressive than other races. Statistics support this claim, but it seems that since many of these races (e.g. Staffordshire Bull Terrier) tend to be popular with unfit owners, the high number of incidents... | [
"In short - there is no evidence. Its just perceived behaviours. ",
"Its not the dog its the owner. You train a dog to be aggressive it will be aggressive. But no one wants a puny little toy-dog breed defending a property. They don't exactly strike fear into humans. But large dog breeds do. Why? because their tee... | [
"This is my stance on it too. That nurture greatly outweighs nature in this particular case.",
"The reason I asked is that I had a heated argument about this with someone claiming that these dogs are bred for fighting and therefore \"have it in them\" to kill other dogs.",
"For reference, the following is the l... | [
"I would have to suggest that the nurture effects far outweigh the effects of nature here. Many species of dogs are prized for their abilities, such as herding instinct, hunting/tracking, and intelligence. But no matter how much potential a dog has, it seems that the distinguishing factors in behavior will always b... |
[
"Converting kinetic energy to xray heat (nukes)?"
] | [
false
] | [deleted] | [
"Through the normal process of heat within a material. Some of the energy comes out directly as neutron radiation, for example. For the rest the fission fragment nuclei/atoms slam into nearby material and transfer their energy to other molecules, which then gets passed around to other molecules in the same manner. ... | [
"Also, the process of fission itself also produces lots of high-energy photons."
] | [
"causes the huge flash before the explosion, right?"
] |
[
"How does a particle carry a force?"
] | [
false
] | For example, how can a gluon be a "particle carrier" of the strong force? How does it work? Bonus question: What is the purpose of a pion if it also carries the strong force but decays almost immediately and doesn't seem to be made outside of Earth? | [
"The idea that forces are transferred by particles shooting other particles at each other isn't really an accurate picture. Particles cause disruptions in fields (for example a charged object modifies the electromagnetic field) and when these particles move, the field around them has to change to accommodate this. ... | [
"No, more like gravitational radiation is for gravity. A quark is like a massive object. Although with the strong force it's a bit complicated because the gluons also have the equivalent of mass."
] | [
"Gluons are massless, but what iorgfeflkd meant (I believe) is that since gluons also carry color, which is the strong force analog of electric charge, they can also interact with each other through the strong force. This is unlike photons which are chargeless and do not interact with themselves."
] |
[
"Are String Theory \"Fuzzballs\" and Loop Quantum Gravity \"Plank Stars\" the same thing?"
] | [
false
] | If I understand correctly, and I probably don't, they both hypothesize that at and inside the event horizon there is some sort of super dense "material", strings in ST and I don't know what in LQG. Both seem to solve the information paradox (inside the black hole there is no infinite collapse to a singularity, so infor... | [
"I notice that nobody else has been able to offer an answer to you so far. I believe this is likely because nobody really ",
" the answer to this question ... so in lieu of an answer, I'll try to offer a perspective on why that may be.",
"The two ideas certainly appear to be similar, at least in all of the way... | [
"Thanx for the answer. I thought LQD did not reproduce GR in the limit. "
] | [
"According to ",
"Wikipedia",
", it is not known whether LQG has the correct semiclassical limit -- it is still an unresolved question, although there has been at least some progress on the problem and so far the progress appears to be consistent with the correct limit."
] |
[
"Where does the energy of red shifted photons go?"
] | [
false
] | Well, the light from distant galaxies arrives red shifted due to the Doppler effect caused by the space expansion. But red photons have less energy than blue photons, so where does all that energy go? For sounds and the Doppler effect, that's easy, because the sound wave becomes longer so the energy is conserved. But t... | [
"Well, the light from distant galaxies arrives red shifted due to the Doppler effect caused by the space expansion.",
"Let's first clarify something. Redshift due to the Doppler effect is not the same as redshift due to the expansion of space (also called cosmological redshift or, in more general contexts, gravit... | [
"Energy is not conserved in general. If we consider energy over a region with only radiation, the total energy decreases due to cosmological redshift as the region expands. If the region is filled only with matter/dust, then the total energy remains constant. If the region has a nonzero energy density (i.e., vacuum... | [
"Nicely written. I never thought about energy conservation and the cosmological redshift before, but reading this made my realize that it can't conserve both the number of photons and the total energy in those photons. So, as a given volume of space V_1 expands to a larger volume V_2, does the total energy stay fix... |
[
"Does improving long term memory hurt short term memory?"
] | [
false
] | null | [
"No, they're two separate mechanisms, and function in different ways. Without needing to dig into the underlying neuronal structures, long term memory acts as just that. Simply put it's a storage box that lots of things can sit in for long periods of time. Short term memory on the other hand has a physiologically d... | [
"This is a hard question to answer, but I'd say probably not. ",
"There are actually many kinds of memory that are lumped together as \"long term\" or \"short term,\" and they are often subserved by entirely different brain mechanisms.",
"Short term memory (a.k.a. working memory) is probably necessary to some d... | [
"Wikipedia",
" says nothing about that.",
"But if you improve your long term memory it should improve your short term memory too and same for all other memory-related parts of your brain."
] |
[
"If space-time is curved, can it really be described in only 4 dimensions?"
] | [
false
] | and if there are more dimensions what would it mean for a dimension to be small (I think I read something involving string theory involving really small dimensions) | [
"Yes it can be described in 4 dimensions. I'm confused as to why you think it couldn't be?",
"When people say that dimensions are small, it means they curl back up on themselves on a small scale. The usual example is that if you have a hose - far away it looks one dimensional like a line, but an ant moving on it ... | [
"You're referring to an embedded manifold, e.g., the curvature of the 2D surface of a sphere can be better understood when described as an object embedded in a 3D space. This doesn't have to be the case, though. There are curvatures that are not better described by embedding them in a higher dimensional space, and ... | [
"Spacetime is a hyperbolic space. In general, it's hard to embed hyperbolic spaces in Euclidean space, without making them infinitely crinkly. There are lots of hyperbolic spaces out there -- google it. For vaguely relevant mind-blowing awesomeness, Google for \"not knot\" - it's a demonstration video that is on... |
[
"If I were making a tin-can telephone, theoretically, what's the best string to use to connect them?"
] | [
false
] | Would it be something dense like a copper wire to transmit the sound waves quickly? Would yarn or twine still be usable over a distance of ~300 yards? | [
"You want a non-stretchy, lightweight, high-tension string. Woven strings will have more friction losses than single-strand.",
"Something like a nylon string would be good, as you want something as rigid as possible in the direction of the line. If you were to choose metal, you'd want something that damps the si... | [
"It may depend on what you mean by \"best\". Do you want something that provides an audible signal at the longest distance? Are you looking for the best fidelity? Fastest transmission? Lowest cost? "
] | [
"Single-strand wire would be best as string needs to have adequate tension in order for any vibration to be transmitted."
] |
[
"What is the lowest possible pH?"
] | [
false
] | In the most recent episode of the Flash the bad guy creates a chemical called Axid which supposedly has a pH of -50. They also neutralized the acid with a computer program, it's not the most scientifically accurate show. Obviously this isn't possible, but it made me think of the question "What is the lowest possible pH... | [
"No a pH of -50 isn't possible as that would give an impossibly large H+ concentration. ",
"When discussing pH it's important to understand that it's a ",
" relative to the most acidic species/ the solvent. The typical pH scale with which acidity is generally taught is based on the pKa of water. In other words,... | [
"Fluoroantimonic acid",
" is the most acidic of known \"superacids,\" and can get down to H = -31, which is >10",
" more acidic than pure sulfuric acid. It is acidic enough to (transiently) protonate alkanes, causing them to expel H2.",
"An H of -50 would be another 10",
" stronger than that."
] | [
"Thank you for taking the time to try to answer my question. You did a far better job than anything else I was able to find."
] |
[
"How can I visualize a matrix product with a vector?"
] | [
false
] | I have trouble wrapping my head around it. For example: say you have a matrix A, vector x, and a new vector Ax=x'. How can I tell what the components of x' stand for? In what way is it connected to a change in basis? | [
"The matrix is a linear transformation of the vector; it takes one vector as an input and gives a new vector as the output. ",
"Here",
" is a list of examples of what the matrix elements look like for some different kinds of linear transformations, and what the transformation does to the vector geometrically."
... | [
"I would ",
" recommend watching ",
"3blue1brown's Essence of Linear Algebra videos",
" it'll answer that question and more.",
"What Ax = x' \"means\" depends on what you want it to mean, in a geometric context Ax = x' usually means some sort of rotation, scaling, and translation, but exactly which one depe... | [
"Take for instance a rotational matrix. You multiply x with said matrix and receive x' (which - if I'm not mistaken - is just a rotated version of x described in the same basis). So how do I know if the new components (x_i)' refer to the old basis (usually standard basis) or new one (columns in the matrix). ",
"I... |
[
"How do fish survive in such harsh conditions?"
] | [
false
] | Obviously if we, as humans were to jump into the sea we would freeze and our organs would obviously give up. How do fish manage to survive in such cold seas? Would their organs not freeze and give up? | [
"Ooh, good question! It's largely down to metabolism, plus a few nifty tricks.",
"Humans are homeothermic, or warm-blooded; we maintain a stable body temperature at which all of our enzymes and other physiological machinery are fine-tuned to perform the most efficiently at. Any deviation from this internal optima... | [
"Nice explication. In addition to, don't forget the thermocline. Water is an interesting substance, for example, when the air it´s very cold outside (example -10ºC) the surface of the water it's freeze (it form a aislant shield) but behing this cape, the rest of the water keep in liquid estate. This is because the ... | [
"This is an excellent topic, as it draws our attention to the environment in which living beings live.",
"I offer as an example: how do flowers, which are very delicate, able to survive in the hot sun day after day? Have you ever thought about what would happen to you if you spent just one total day in the same c... |
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