title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Is rinsing, say, leafy vegetables an effective way to reduce the amount of pathogens and chemicals on the surface?"
] | [
false
] | null | [
"It's more so for the dirt and other macro particles on the vegetables. But while pretty much all pathogens wouldn't by soluble in water the force of running water alone would be enough to \"knock\" a good chunk of pathogens off the produce. Hot water would probably be the most effective in removing pathogens speci... | [
"Wondering a little bit about things that can be picked up along the way of production, transporting, super market handling. Personally, I don't necessarily care too much about it, but i was curious. "
] | [
"I can't speak to the specifics of this, but I do know that a lot of soil and \"dirt\" isn't removed after harvest and I'd imagine basic pathogens are acquired via human handling during transit. Again, a basic washing will remove most of these contaminants and even eating them will probably do little to harm to you... |
[
"Why can objects only travel at light speed in a vacuum. Theoretically shouldn't they just be able to accelerate to much higher than that? Photons especially have no weight so why are they limited to 300000 km/s."
] | [
false
] | I apologize in advance if this is a stupid question. | [
"There's a common story that as a massive object accelerates closer to the speed of light, it gets heavier and heavier, so applying a constant force accelerates it less and less. This is an antiquated and not particularly helpful way to look at things, based on shoehorning relativistic equations into a Newtonian (i... | [
"I assume you're asking why it's any value (and not the specifics of why it almost rounds easily with meters and seconds, which is partially coincidence and partially by redefinition of units). ",
"Ultimately physicists would love to give you a good answer for this — e.g., \"it ",
" to be that number for a very... | [
"It is not a field that imposes these limits. It is the structure of the spacetime we live in. We have a fairly detailed understanding of that structure - it's a specific type of Lorentzian manifold.",
"For this kind of spacetime, if you select any given spacetime point as the \"origin\", there will be what we ca... |
[
"What reflex arc mediates the reflex of holding breath when wind blows in your face?"
] | [
false
] | That happens involuntarily and nearly instantaneously when facing strong wind. It is most often seen in children. You can sometimes trigger it by putting your head through the car window when driving really fast. I wonder what are: the receptor, the afferent neuron, the integration center, the efferent neuron (n.laryng... | [
"This is caused by the ",
"dive reflex",
". The afferent arm of this reflex is not well defined, but facial cooling by convection (air or water) triggers the reflex, suggesting temperature sensation conveyed by the facial nerve constitutes part of the afferent signal of the reflex. The efferent signal for respi... | [
"You know, you're right. You can find studies about apnea triggering the dive reflex, but not vice-versa. I had been taught that this was the result of the dive reflex, but it is quite difficult to find any peer-reviewed evidence to support this position. On the other hand, if you google breath-holding in babies wh... | [
"Thank you for your answer.\nThe effects of dive reflex are bradycardia, peripheral vasoconstriction and blod shift. Nothing about involuntary breath holding.\nAnd the paper says: \"...diving bradycardia is triggered by apnoea and accentuated by immersion of the face or whole body in cold water.\"\nBut when facing ... |
[
"Has anyone thought of doing this during an earthquake with a drone?"
] | [
false
] | I always wondered how the earth moves when earthquakes occurred. Most videos on the internet show this with shaky camera footage moving WITH the earthquake. I want to see how the ground moves from a very stable and stationary standpoint. What if scientists programmed a drone to fly upward and immediately start filming... | [
"I'm not aware of anyone proposing to try this. There's no specific reason this isn't possible and it could be implemented in an area with an ",
"earthquake early warning system",
", which relies on a dense array of seismometers and automated systems to identify / locate an earthquake and send out alerts (explo... | [
"In terms of visibility, it's less the amplitude that is important, but the wavelength. Earthquakes are noisy and so the periods of surface waves can be pretty variable (and have multiple, superimposed components), but short periods waves might have periods of ~1 second. So at velocities between ",
"2-5 km/s",
... | [
"I'm curious - do you think the amplitude of the waves would actually be visible? You'd definitely be able to observe the effects on structures. But how much does the ground itself really move up and down or side to side during a quake? A couple feet? A couple inches? I can't imagine you'd see much ground movement... |
[
"How does constant stress affect the body?"
] | [
false
] | If a group of people were under constant psychological and physical stress for extended periods of time (months or years) how would that affect them? If we take the situation in The Walking Dead as an example (ignoring the fact that there are zombies) where a small group of people are constantly in danger, have to enga... | [
"I GOT THIS, I GOT THIS ONE. Ok, so, I've been studying effects of chronic stress in humans and wildlife (mostly wildlife) full time since 1990. Really crudely: chronic stress is basically a state of too much cortisol/corticosterone for too long a time. (this is oversimplifed - other hormones are involved too - bu... | [
"Allostatic load",
" is essentially the cumulative effect of chronic stress on a human. This effect is believed to exert itself through hormones such as epinephrine. There are multiple papers on the relationship between allostatic load and conditions such as diabetes and heart disease. ",
"Here",
" is a paper... | [
"In different quantities. It's not clear though if there might be a \"threshold dose\", beyond which the body is basically in full-on stress mode no matter what. It hasn't been studied much though - most research involves giving \"high cort\" to an animal or person and then just seeing what happens, without as much... |
[
"What are the actual addiction rates of various drugs?"
] | [
false
] | [deleted] | [
"Not exactly what you asked, but you may be interested in ",
"this article",
", and ",
"this looks like the actual paper",
". It's an attempt by David Nutt et al to classify drugs by personal and social harm."
] | [
"Here is the graph (image) for that article, and one more about active/lethal dose ratio: ",
"Graph: ",
"Rational scale to assess the harm of drugs (mean physical harm and mean dependence)",
"\nSource: Nutt, D., et al. \"Development of a rational scale to assess the harm of drugs of potential misuse\" The La... | [
"What do you mean by \"addiction rate\"?"
] |
[
"How are underwater tunnels built? (Such as the one from Copenhagen to Malmö) Additionally, what steps and precautions are taken to ensure it will not flood both during and after construction?"
] | [
false
] | null | [
"This is called an ",
". The first thing to do is to cut a trench in the seafloor along the route of the tunnel. Meanwhile, prefabricated sections of the tube are built in dry docks from steel or reinforced concrete. These are then sealed at each end with temporary bulkheads and floated to the construction site.... | [
"Rough seas are only rough at the surface, drop a few more feet and you don't feel it. The tunnel would likely be well under that.",
"Edit: Please stop messaging me to tell me the floats would be subject to the surface waves. Floats can be submerged, the tunnel itself can be made buoyant. They just need markers a... | [
"I the problem I could see with the floating tunnel would be ship anchors like you mentioned before. Also what happens if the floats are damaged by shipping traffic or rough seas? I’m sure a many redundant systems would be used but but still. "
] |
[
"How did scientist measure the speed of light?"
] | [
false
] | null | [
"One of the early measurements of the speed of light comes from astronomy. The basic idea is this. You set up a telescope to look at Jupiter, specifically you follow one of the moons as it goes around. You make the assumption that the moon has a fixed period for going around Jupiter. For example, the moon Io makes ... | [
" Deliciously, you can measure the speed of light with a sausage and a microwave.",
"http://imgur.com/gallery/uiwcv"
] | [
"The first accurate measurement involved sending a focused beam through a gap in a rapidly rotating cogwheel and bouncing it off a distant mirror and back to the cogwheel. The rotational speed at which the light is reflected back through the next wheel can be used to ascertain the speed of light. You can read about... |
[
"Absolutes in the universe. The speed of light is one but what else is an absolute?"
] | [
false
] | Racking my brain and I don't have a good answer. What are the absolutes in the universe? The speed of light is one of them but I'm having a hard time finding more. From what I understand things like mass are not absolute, they are relative to other masses. Its the above correct? | [
"From what I understand things like mass are not absolute, they are relative to other masses.",
"No, a mass is a mass. Velocity is relative but mass is not.",
"We don't really use the term \"absolute\" much, but if you're looking for \"constants\", then there are a ton of those-- fine structure constant, electr... | [
"You can't really say the speed of light is absolute by that logic either then. You can't measure the speed of light with just the speed of light. ",
"If you're talking about constants in the standard model, then there's a bunch of them. Mass ratios is certainly a nice example"
] | [
"I don't know what exactly you mean by absolute, but speed of light is not so. Constant \"c\", is defined as speed of light in vacuum. Light goes much slower in water or glass for example."
] |
[
"Food pairings, how do they work? Why do some foostuffs have comlementary flavors which call out for one another, while others don't? Is it purely cultural or is there a physiological underpinning to this?"
] | [
false
] | Examples of pairings: Maple pie with milk, smoked meat or hot dogs with mustard, strawberries and cream counter examples: mustard and strawberries, pickles and cream It's the same food and there is nothing wrong with it, yet in one combination it is exquisite and in another disguting to most. | [
"All \"flavours\" can be broken down into 2 main parts; tastants and aroma. ",
"Tastants are the main taste groups; bitter, sweet, salty, acidic, & umami. They give the \"flavour\" more body, and often can change the entire perception of the \"flavour\".",
"The aroma is the complicated part. Whereas each of the... | [
"You're right, metals, like copper or iron, have a distinctive taste. I had this exact discussion with one of the flavourists 2 weeks ago, he better characterised the taste as that of \"licking a 9v battery\". His comments were along the line of the full sequence of events from metal binding to the taste receptor t... | [
"bitter, sweet, salty, acidic, & umami",
"Are these really all there is? I think some metal can have a very strong and distinctive taste, for example damaged spots on cutlery (though none of the metal in my office had it). It's a taste that doesn't remind me of any of the above.",
"Also, rodents have fatty acid... |
[
"Are people with long covid considered compromised and more susceptible to further disease from covid reinfection, flu, bacterial infection etc?"
] | [
false
] | null | [
"\"Long COVID\" is not a currently accepted diagnosis in the medical community (I am a doctor in NYC and treat/have treated many COVID patients as part of my specialty -- I therefore can be considered somewhat of an authority on this subject). There is no evidence of a persistent or ongoing COVID infection in certa... | [
"I remember reading articles talking about scaring in lungs and heart of covid patients even that did not show symptoms. Is there any merit behind that?"
] | [
"People don't think that if they have long COVID or if others do that they are still contagious. It's obviously another term for post COVID. With the long part referring to long haulers/long lasting symptoms, not having the virus itself. It's the main term being used by people with long/post COVID and it's being... |
[
"How did monkeys get to the New World?"
] | [
false
] | null | [
"This topic has certainly been the subject of some debate! It's clear that primates evolved in the Old World and that the ancestors of New World monkeys arrived there later, but this still leaves three broad possibilities we could imagine:",
"Various connections",
"Brikiatis 2014",
"Graham 2018",
"probably... | [
"Nobody knows, they think they came across on a land bridge that has since been submerged or floated across on vegetation rafts. It's hard to find fossils in a rain forest.",
"https://www.charlotteobserver.com/news/science-technology/article9097880.html"
] | [
"It must have been a fairly common occurrence, I would imagine that some types lived near the ocean and the occasional tree would fall in with a monkey or two still in it. They just sort of toughed it out until they hit land again. Also thirty million years ago Africa and South America were a lot closer together ... |
[
"A black hole is a strong example of the gravitational force. Are there other incredible examples of the other 3 fundamental forces? Like \"an electric hole\" or something?"
] | [
false
] | edit: Thanks guys for all the cool answers! | [
"Since gravity is several orders of magnitude weaker than the other 3, you could argue that what you see everyday (electricity as electromagnetic, an atom's nucleus as strong and radioactive decay as weak) is already an incredible example of a fundamental force. However, the universe as a whole has pretty much neut... | [
"I'm pretty sure mass bends spacetime and we have named that bending 'gravity'"
] | [
"I'm pretty sure mass bends spacetime and we have named that bending 'gravity'"
] |
[
"Do other mammalian species experience difficulties with breastfeeding?"
] | [
false
] | So many human women have trouble breastfeeding their newborns (latching problems, milk supply problems, etc). Is this issue unique to humanity, or do whales, dogs, and raccoons have these problems too? If it's a human-specific problem, why? | [
"I read an NPR article about an anthropological study of breastfeeding in an isolated Namibian culture (",
"https://www.npr.org/sections/goatsandsoda/2017/06/26/534021439/secrets-of-breast-feeding-from-global-moms-in-the-know",
"). Short version: despite living in a culture where bare breasts and breastfeeding ... | [
"This is barely tangential to OP's question but I would like to see a study comparing the rates of breastfeeding difficulties between cultures that cover their breasts and those that don't. I would assume that cultures which don't cover their breasts provide built in learning opportunities for young girls and teena... | [
"Yes, other species can experience milk supply problems or poor udder development.",
"Here is an article on agalactia (failure to secrete milk) in horses. ",
"https://www.vetstream.com/treat/equis/diseases/female-agalactia-hypogalactia"
] |
[
"When does the body stop undergoing catabolic reactions that lead to weight loss?"
] | [
false
] | I think we've all heard it.. if you want to lose weight, your caloric intake must be less than the number of calories you burn through exercise, basal metabolic rate, etc. However, we've all also heard that anorexia doesn't work because the body stores up fat. So how do these two 'theories', if you will, work together? | [
"You are correct",
":",
"an·o·rex·i·a [an-uh-rek-see-uh] noun\n1. loss of appetite and inability to eat.",
"But why not supply a definition instead of just making a claim?"
] | [
"I caution you about rapid weight loss, which is often not long-lasting. If you want long term results, the best diet is the diet you can stick to. Keeping a food journal helps you realize where some excess calories might be coming from. ",
"You might find some motivation and help over at ",
"/r/loseit"
] | [
"I think you are referring to the commonly experienced plateau in weight loss when someone starts a caloric restriction diet. It is theorized that this would serve an evolutionary advantage when our ancestors were faced with long periods of famine.",
"But to address your observation of conflicting theories, we ne... |
[
"Why is dimethylmercury so toxic?"
] | [
false
] | So I know that mercury is a toxic element to humans, but I'm curious as to why dimethylmercury is so much more f-ing toxic. Does anyone know the chemistry behind why it's so much better at snuffing us out? Thanks! | [
"See the safety link on ",
"wikipedia",
".",
"Basically it comes down to a few factors:",
"-high vapor pressure means it evaporates quickly so you can inhale it if it is in the same room as you.",
"-it sounds like it is fairly soluble in things (latex, pvc, etc...) including human skin. So spill some on ... | [
"Awesome, thanks for the answer bud!"
] | [
"Dimethylmercury forms a methylmercury-cysteine complex (sulfur-containing amino acid) due to a soft acid-soft base interaction. The ease of which it can transport through the body and through the BBB may be due to methionine transporters recognizing methylmercury-cysteines as methionines (they are similar in struc... |
[
"What are the risks associated with the different means of energy production?"
] | [
false
] | We've all seen the news, did nuclear power suddenly get more dangerous or is it just popular opinion? Is solar the way to go? I've seen hints of cold fusion, is that still fiction? What would that change? | [
"Here's the oft-quoted data for ",
"deaths per TWh",
". What this does is divide the number of estimated deaths caused by different sources of power by the amount of energy generated by that source. "
] | [
"Nuclear power is more dangerous for the fact that new nuclear plants aren't being built. If you're from the US most of your nuclear power plants will be from the 70's ... you can just imagine how the technology in running, maintaining and engineering such a facility has taken giant steps forward since then. I come... | [
"Here's a partial list of some \"risks\" associated with some of the most common forms of energy production.\n",
": , ",
"env. damage of mining; putting \"old carbon\" and Mercury in the atmosphere causes acid rain and climate change,",
" & ",
"air pollution that causes respiratory conditions.",
"\n",
"... |
[
"When brain imaging techniques become more detailed, will it be possible for researchers to see hallucinations the patients are having?"
] | [
false
] | I'm thinking specifically of the video that came out recently that showed scientists were able to view images directly from a patients brain. When these techniques become refined and can produce a clear image, could we possibly see hallucinations from a person with schizophrenia? More so could we see the hallucinations... | [
"I'd never say it was impossible, but there is a huge difference between showing the visual input, which is pretty well spatially mapped out in the visual pathways versus the ",
" of that input, which is in the visual association cortex."
] | [
"That makes sense. Thanks man. "
] | [
"Also you'd have to get them to stay very still."
] |
[
"Static electricity: How long does it last?"
] | [
false
] | Preface: So I was in my bathroom the other day opening a packet of cigarettes. Anyone familiar with cigarette packaging knows they have a plastic film around the cardboard packet. I ripped off the top part of the plastic, then slid the main sheath off the packet body. When I did, the plastic became charged, and stuck t... | [
"It is possible to put a charge on a completely non-conductive material (such as your cellophane packaging). The charge doesn't have anywhere to go as long as it doesn't come into contact with something which can mitigate the charge (either by dispersing it or sharing it). ",
"Depending on the atmosphere around... | [
"Yes and yes. Get your hands wet and touch the wrapper inside and out; it'll discharge. Put it in a humid bathroom for a while, it'll discharge. Leave it in a dry room and it might last months. Put it in a sealed, nonconducting container and it'll be charged when the next race finds it in an archaeological dig.... | [
"The static electricity will remain (diminishing) until it has discharged and the potential difference between the two bodies is equalised. The packet will fall off when the electrostatic forces between the packet and the door are not large enough to hold the packet in place against the force of gravity.",
"Try t... |
[
"If we travel are relatively quickly in one direction (10% light speed), will there be a difference in the Cosmic Microwave Background as we look around (in terms of frequency)?"
] | [
false
] | Could we not use this as a method of identifying a "universal" velocity? | [
"Yes, it gets redshifted and blueshifted like any other radiation source. If you were to travel in one direction, the CMB ahead of you would be hotter and behind you it would be colder. Based on how the CMB dipole moment looks right now, we can determine we are moving about 600 km/s with respect to a frame in whic... | [
"Forgive my ignorance, but doesn't this velocity with respect to a 'universal frame' contradict the adage that velocity is always relative to something?"
] | [
"If I decide to measure all velocities with respect to my current (inertial) frame, it would be a special frame too! The 0 dipole moment frame is just a convenient one, as a center of mass frame might be in other contexts.",
"The key point is that properly constructed laws of physics apply in any of these frames... |
[
"Could we be slowing down our own evolution?"
] | [
false
] | null | [
"This is a better question for our sister subreddit, ",
"/r/AskScienceDiscussion",
". All the best!"
] | [
"You may have to wait a bit before you can re-post (or verify your e-mail address). That's a reddit issue, not anything I can control. Sorry."
] | [
"It doesn't want to let me re-post there. I'm not a frequent poster, so I'm in unfamiliar territory. Advice?"
] |
[
"Why does this ONE tree have leaves growing out of it while: A) The canopy is dead, and B) No other trees do?"
] | [
false
] | null | [
"It looks like that is some other plant growing ",
" the tree, rather than the leaves of the tree itself. Trees don't generally grow leaves right out of their trunks. I couldn't tell you what the plant is, but if you get a closer photo of the leaves, maybe someone could help."
] | [
"Trees sometimes produce adventitious buds, small branches growing out of the trunk, as a result of disease, stresses, or the introduction of new light through the felling of a neighboring tree. You could therefore see something like this picture occur. However, since no other trees (at least of the species that ... | [
"I'm not sure if the plant with leaves you photographed is the same as the tree but I can answer your inquiry anyways.",
"First, consider this: in tropical and some warm temperate zones plants ",
" because maintaining them requires a lot of energy investment and water supplying, which is complicated during dry ... |
[
"Shouldn't gravity break the speed of light?"
] | [
false
] | null | [
"No. ",
"Since particles at least have some kind of mass",
"This is not true, a particle need not have mass. Photons (quanta of light) are massless.",
"shouldn't gravity act upon these particles",
"Gravity does act on them. Gravity is the result of curved spacetime which depends on the energy distribution "... | [
"Gravity doesn't change the speed of light, it changes the energy of the light. If I were on the moon and shone a laser at the Earth, it would be slighter bluer on Earth. The light had increased in energy.",
"Conversely if I were to shine a laser up at the moon, it would look slightly redder than on Earth. ",
"... | [
"Also, the velocity of a photon can not exceed the speed of light, though it can be slower than the speed of light.",
"That's not true: A photon will always travel at the speed of light. Light can be slowed by a medium (e.g. glass), but that is due to absorption and re-emission of photons: The velocity of the ind... |
[
"How does a small caliber bullet kill someone?"
] | [
false
] | [deleted] | [
"Something no one has mentioned yet is hydrostatic shock. A bullet with a high enough velocity, even if it is of a very small caliber, can create a shockwave upon impact. This shockwave can travel through the body, damaging organs or that are relatively far from the point of impact. Getting shot in the torso can ca... | [
"yep yep! as we learn in our trauma surgery classes, the biggest damage done almost always is due to the force of impact, not to the bullet alone."
] | [
"There's not a whole lot of extraneous \"stuff\" in the human body -- it all serves a purpose. Because of how efficient and compact the human body is, there are a lot of critical organs that are small, easily disrupted, and highly vascularized crammed in a relatively small space. Of course it all depends where this... |
[
"What the hell just happened? Thermite over water result was perplexing..."
] | [
false
] | null | [
"I at least partially figured it out. The flame initially starts at the very top near the foil. The burning embers left must be the ignition point. But I'm still not sure what's burning. It must either be the company of the dissociated water or aluminium powder, but I'm unsure of which makes sense. The color of the... | [
"I at least partially figured it out. The flame initially starts at the very top near the foil. The burning embers left must be the ignition point. But I'm still not sure what's burning. It must either be the company of the dissociated water or aluminium powder, but I'm unsure of which makes sense. The color of the... | [
"I've come to the conclusion that there must be a zone around the burning thermite that is close enough to dissociate the water molecules but not close enough to ignite. Likely that the molecules rapidly cool in the relatively cold water. I may be able to verify this by using boiling water, but it would have to be ... |
[
"What makes coffee a diuretic?"
] | [
false
] | I'm really curious as to why it does. I'm a regular coffee drinker and about 30 mins to an hour after I start drinking I need to go to the bathroom. Is there any chemical or biological reason as to why this happens? | [
"Caffeine is an ADH inhibitor (same as alcohol). Acts to decrease your sodium reabsorption at the collecting duct of the kidney, meaning you are peeing out more water and retaining your salts. "
] | [
"Caffeine ",
"increases glomerular filtration and inhibits Na+ reabsorption",
", which increases the urine output. Don't know the exact biochemical action for reabsorption. Increased filtration may be due to the increased blood pressure induced by caffeine."
] | [
"Thanks. Meant to write \"action for ",
" reabsorption\"."
] |
[
"Does matter with a net charge have to be at a higher density before it forms a black hole?"
] | [
false
] | [deleted] | [
"I'm going to reformulate your question into the following: given two spherically symmetric matter distributions, one charged, and one uncharged, both with Komar mass M, does the charged matter distribution have a smaller event horizon?",
"The answer to that question is yes. The ",
"Reissner–Nordström metric",... | [
"Yes, at least based on the simple argument that you have to compress matter to within its Schwarzschild radius (the size of the resulting black hole's event horizon); charged black holes have smaller event horizons than uncharged black holes, but no smaller than 50% of the uncharged radius, so it's not a huge diff... | [
"This is a tricky question: If there is a large net charge, then there will be some extra potential energy in the system. That ",
" the rest mass of the system, making it easier to form a black hole. So, if you could somehow strip all the electrons from every atom in the earth, you might think the earth would be ... |
[
"Why does the electricity in this video seem to rise?"
] | [
false
] | Was curious about a gif I saw in | [
"When the electricity arcs through the air, it creates a plasma. The plasma is much hotter and less dense than the surrounding air, so it rises as you'd expect. The plasma has much lower electrical resistance than the air around it, so even though the distance the electricity must travel increases as the hot plas... | [
"That's right, but you didn't quite mention that the arc rises because it is passing through heated air. That's why the arc rises (it doesn't just look like it is moving upwards, it really is. Because the path of least resistance rises, because it's warmer than the surrounding air.)"
] | [
"That's right, but you didn't quite mention that the arc rises because it is passing through heated air. That's why the arc rises (it doesn't just look like it is moving upwards, it really is. Because the path of least resistance rises, because it's warmer than the surrounding air.)"
] |
[
"Why is the brown bear's latin name \"Ursus Arctos\"?"
] | [
false
] | I mean, polar wolf is Canis Lupus Arctos, but polar bear is Ursus Maritimus? And brown bear is Ursus Arctos? Why is that? | [
"Both \"ursus\" and \"arctos\" mean \"bear\"--\"ursus\" in Latin, \"arctos\" in Greek. ",
"\"Ursus arctos\" is simply the brown bear, which is found in North America, Asia, and Europe--the double name may imply that it, of all bears, is the true and archetypal bear. "
] | [
"Because Linnaeus gave it that name. Ursus is Latin for bear and Arctos is Greek for bear. I don't know why Linnaeus decided to name a bear with two different words for bear.",
"Calling the north polar regions the Arctic is itself derived from Arctos, in reference to the northern constellations Ursa Major and Urs... | [
"Less and less so. Latin is not mandatory *per se*, and use of other languages is gaining in frequency these days.",
"Consider, for instance, my friend Derek Armstrong's latest find: [",
"](",
"https://gizmodo.com/this-400-million-year-old-worm-monster-is-metal-as-hell-1792584414",
"). The name is derived ... |
[
"How do lesions form in the brain apart from injury / trauma ?"
] | [
false
] | Lesions can form in the brain with ( repeated ) head trauma or head injury. But how do they form in a person if there has been no instances of head trauma or injury? Physiologically. | [
" is of course a pretty general and nonspecific term. Basically almost any abnormality. So a short list:"
] | [
"Thank you very much! This is exactly what I was looking for and was very informing."
] | [
"Out of these are there or any cases where lesions would only form in the brain, not anywhere else in Central or peripheral NS. Ignoring / forgetting about anything viral, bacterial, tumor-related, or cancer-related. Where the spine would look completely healthy."
] |
[
"How Can a Computer be Programmed to Play Chess against a Human? Why are Some Computers (Deep Blue) Better for this Purpose?"
] | [
false
] | Is it the software or hardware? What is it that makes a good chess computer? | [
"[I am an AI prof and regularly teach a course where students build chess-playing programs.]",
"A chess computer works by looking ahead at all possible games played out to increasing depth, choosing the move that leads to the best-looking result with best play by opponent. This is called the \"negamax algorithm.\... | [
"Some. ",
"Historically, computer Go programs have been horrible. I ran the computers at the 1997 National Conference on Artificial Intelligence when they held their first Human/Machine Exhibition matches in a variety of games. Janice Kim, a former Korean Womens' Champion, beat the best program in the world, ",
... | [
"Effectively, yes, higher levels are typically deeper searches. (Usually time-based rather than depth-based, but amounts to the same thing.)",
"Yes, the computer will choose the best move given the depth it searched and the quality of its evaluation function. Programs search way deeper than humans but their posit... |
[
"Is it likely that there are stable particles that exist but have still been undiscovered?"
] | [
false
] | Stable particles being defined in this case as particles with a very long half lifes like a protons, neutrons and electrons. | [
"It is possible. Dark matter is one such possibility."
] | [
"yes, but you need to separate your question in two categories, first we have particles that exist in theory but haven't been detected yet, for example the most elusive of them all, the Higgs. Some others can be the axion, graviton, and many supersimetric particles that haven't been detected yet. These particles ex... | [
"another thing, neutrons are very unstable, their lifetime is about 15 minutes, it is just very puzzling that if you pair them with protons, the neutron becomes very stable."
] |
[
"What are the chances of a white female giving birth to black baby seeing that she had never had sex with a black person?"
] | [
false
] | null | [
"There are birth defects that can affect skin color. Melanism is one, but that's extremely rare in humans. I've seen very few pictures, but my understanding is that a white person with melanism would look like a white person with very dark skin rather than a black person--but I've also met ethnically black people w... | [
"Melanism in humans has only be observed affecting specific internal organs."
] | [
"Define black baby.",
"How dark does it have to be?"
] |
[
"As simply as possible, why don't photons interact with the higgs field?"
] | [
false
] | If a higgs field provides mass to particles, and photons do not have mass then I presume photons must not react with the higgs field? If so why? Or is there another reason why they are mass-less? As a student still in secondary school I'm not at university level physics yet so if you could explain it as simple as possi... | [
"At the level of the Standard Model of particle physics we can't answer that question. All of the masses of the fundamental particles have to be set to the values that they have in order to match with experiment (It's true that the interaction with the Higgs field is what ",
" them to have a mass, but its numeric... | [
"We simply observe that the photon is massless, so we add a massless particle into the standard model.",
"I don't think that is entirely correct in the case of the photon. My understanding is that the masses of the electroweak bosons are to a degree constrained by the Higgs mechanism (see for example eq. 29 of ",... | [
"That's true, there are some relationships between the masses of the EW bosons, but the value itself of one in particular is undetermined and has to be measured. The fact that one is left massless is a consequence of the pattern of symmetry breaking, but that just raises the question of why the symmetry is broken i... |
[
"How can a speaker replicate two sounds at once if it only has one diaphragm?"
] | [
false
] | For example two violins makes two separate waves when bowed which translates to air waves. our ear is literally hears waves originating from two different points but with a speaker you have one diaphragm producing two three ten twenty or more notes and frequencies simultaneously. how is this possible when there is only... | [
"A violin string is vibrating in a relatively simple manner - a standing wave and maybe some harmonics.",
"A speaker is vibrating in a more complex manner - each of the waves for each of the sounds in question is essentially added together, resulting in a single wave that contains more than one distinct thing tha... | [
"Even violin strings make more than one frequency of sound. The way these waves works is described by the Fourier series of mathematics.. That basically show that any sound, or sounds are a combination of different sine, and cosine waves. ",
"A speaker moves due to the manipulating of magnetic fields made from an... | [
"Good.. Since I felt I was rambeling. But it is an extraordinary feture, just how many frequencies a single speaker can replicate."
] |
[
"What is the average temperature *of* the Earth, approximately?"
] | [
false
] | Not the temperature the Earth, but including the mantle, core, etc. what would the average temperature of the Earth be? | [
"This is ",
" back of the envelope, but somewhere around 2100 C. This assumes a surface temperature of 0 C, a temperature at the base of a uniform 50 km thick crust of 1000 C, a temperature at the base of the mantle at 2900 km depth of 3000 C, a temperature at the top of the outer core of 3700 C (to account for t... | [
"Exactly what I was looking for, thank you!"
] | [
"Sometimes you just have pointless random questions torturing your mind. This is my first guess."
] |
[
"How are Allosaurus fossils so widely distributed across the globe when, at the time of their existence, Pangaea had already broken up?"
] | [
false
] | Depending on where I search, Allosaurus existed between 155 to 135 million years ago - in the Late Jurassic period... Fossils have been discovered in the Western U.S., Tanzania, Portugal, and Thailand... Everything I've found so far about geology of the time has Europe, Africa, and North America separated, and some thi... | [
"Look at ",
"Gonwanaland",
" and ",
"Laurasia",
". These broke up, splitting Pangea, near the Jurassic-Cretaceous transition."
] | [
"Plate reconstruction people are very much competitive, but none would be bold enough to dispute the fossil record."
] | [
"Yes, but Africa, N America, and Asia were all connected by land through that time period. ",
"Video",
"."
] |
[
"Does Hawking Radiation Accelerate or Slow based on the mass of a black hole?"
] | [
false
] | [deleted] | [
"Larger black holes give off less Hawking radiation than smaller ones."
] | [
"That is what Stephen Hawking proposed. Others think that there is a point where a black hole becomes too small to interact with particles and essentially becomes a stable ",
"WIMP",
". These ",
"micro black holes",
" could be what dark matter is comprised of."
] | [
"Thank you. So in a sense, as a black hole evaporates, the amount of Hawking radiation from that black hole accelerates until it erodes completely in some kind of big explosion at the end?"
] |
[
"what would happen if one stopped having social contacts?"
] | [
false
] | Is social interaction a natural need like eating and drinking? | [
"This is an often asked question. The need to belong vs. social isolation is a fascinating subject, to the point of being included in Erikson's theory of ",
"psychosocial stages of development",
". ",
"Your question does not specify the circumstances under which an individual is denied social contact, so I ... | [
"/u/NawtAGoodNinja",
" answered your question beautifully. However, i'm just going to deviate a little bit and talk about the effects of social isolation on the development of neglected children. ",
"Socioemotional deprivation of young children has shown to physically change their brain structure. Studies cond... | [
"As you said, I would think that the main factor in solitary confinement is just the lack of anything to do, rather than just not having any social interaction. I would think that some types of personality would fare decently well living in isolation in nature and with enough things to stimulate the intelect. Is th... |
[
"Why do most animals mature faster than humans?"
] | [
false
] | I was having a conversation with my roommate and I didnt have an answer to why most animals are born with the natural ability to be able to walk and humans aren't. Baby giraffes and elephants, cows, ect. Besides the fact that humans have evolved, do we know if earlier humans were born with somethings that we have to le... | [
"The question implies an understanding of maturation that isn't quite accurate. Human's mature over a longer period of time because there is much more to develop. Obvious physical development is only one portion of the entire process. Human mental development is far more sophisticated than even the next most int... | [
"Thank you."
] | [
"\"In stable or predictable environments, K-selection predominates as the ability to compete successfully for limited resources is crucial and populations of K-selected organisms typically are very constant and close to the maximum that the environment can bear (unlike r-selected populations, where population sizes... |
[
"When probes and rovers are sent to other celestial bodies, how do the operators account for the delay when sending commands due to the speed of light?"
] | [
false
] | null | [
"Opportunity downloaded all of it's commands for the day at once, and stored them for execution over the course of the day. ",
"This caused some problems when the rover would hit obstacles like sand- it would spin its tires all day until it was buries extra deep. That's how Opportunity's sister Spirit died. A hot... | [
"You can't do much but wait. You send a signal, it takes however long it takes to get there, the rover sends a signal back, and it takes its time coming back. That's part of why rovers tend to move very slowly. One, they want to be careful and not get stuck, 2 round trip signal travel time can be more than 20 minut... | [
"Do you have a reference for this?"
] |
[
"Do we know that every proton is EXACTLY the same as every other proton?"
] | [
false
] | Beginning to look into chaos theory and this seems like applicable information. | [
"Yes, a proton is defined by quark flavour. Up, up down is what we define as a proton. \nThis leads to the properties such as rest mass and charge that we expect for the proton. \nThe anti proton is comprised of anti- quarks of the same arrangements but the quarks are \"anti\" to that of the protons, leading to sa... | [
"You can indeed prove that there are no differences, because certain theoretical predictions will yield a different result if the particles are distinguishable. Then you only have to check wether your experimental results agree with the prediction for distinguishable particles or with the prediction for identical p... | [
"Whoa, who said quantum mechanics should make sense?",
"Now, seriously, you could design a different device which group the photons differently. Arkhipov's predictions depend on the assumption that, since the matrix which represents the interferometer is under the Haar measure, you can approximate such a matrix i... |
[
"How to make/maintain an artificial star?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"/r/HomeworkHelp",
"guidelines.",
"/r/AskMath",
"/r/AskPhysics",
"/r/PhysicsHelp",
"/r/chemhelp",
"/r/AskEngineers"
] | [
"What do you mean it's not the correct place to ask for help on a research project? You're description is litterally about helping people with scientific questions. What about my question isn't scientific?"
] | [
"The subreddit is not here to solicit work for your project."
] |
[
"Could I acclimate to higher levels of electrical shock by slowly increasing the voltage or amperage?"
] | [
false
] | A friend posed this question to me, and it got me thinking. I thought it may work in the same fashion as the 'boiling frog' experiment. Is this possible? Thanks in advance for your comments. | [
"Could I acclimate to higher levels of electrical shock by slowly increasing the voltage or amperage?",
"No, you cannot. The reason is your nervous system relies on electrical signals to function. Repeated shocks would probably only wear you out and stress you, but it's not like acclimating to cold water or somet... | [
"Well, if you smash your thumb enough times, the nerves will probably die, problem solved!"
] | [
"ACtually yes it does. You can touch the terminals of a car battery with dry hands (12 volts at a huge lethal number of amps) and won't get shocked. Don't try it, just go and ask you mechanic."
] |
[
"Why don't we dispose radioactive waste in space ?"
] | [
false
] | Instead of building underground bunkers and storing them here on earth. | [
"Because that's prohibitively expensive and there's a chance the rocket could fail and spread radioactive waste over a much larger area."
] | [
"1) It costs a lot to move mass into space. Using ",
"this",
" table, we can see that the lowest $/kg is ~$2.2k. According to ",
"this",
", the total amount of radioactive waste in the UK is ~5 million tonnes, which means it would cost ~$11 trillion dollars to launch just the UK's waste into orbit, ignoring... | [
"You can send stuff into space without it necessarily going into orbit though"
] |
[
"How far will electricity travel in water?"
] | [
false
] | A hurricane hit my country a year ago. People were warned to avoid exposed power lines in the water. I want know how far is too far. | [
"Technically, I think the answer is \"all the way\" as water can conduct electricity a basically unlimited distance. In some situations you could measure electrical currents through kilometers of water.",
"However, how much current will flow depends on a lot of factors. The resistance of water per centimeter of d... | [
"Electricity will follow the lowest resistance path.",
"Electricity will follow all paths, a path with a lower resistance just gets more current than others."
] | [
"Yes, that's much better put. Thanks!"
] |
[
"Why doesn’t thunder happen all at once? Why is the sound spread out?"
] | [
false
] | null | [
"Thunder happens when lightning burns it's way to the ground through the air creating a shockwave along the length of the strike. \n For all intents and purposes, lighting is almost instant, so you have a shock wave emanating from every location the lighting propagates through the air at the same time. Because the ... | [
"In addition to what has already been pointed out, close to the lightning bolt, the thunder is so loud that it affects the speed of sound at the wave front. This leads to a situation where the high frequency waves propagate at a different speed than the slow ones and thus the sound is distorted and stretched in tim... | [
"When the lightning strikes really close, the sound is more like a 'clap' or a 'crack' or a 'crack-prrt': more instantaneous.",
"The 'spreading out' was described by ",
"u/lamblane",
". To add to the description, variable density, temperature and motion of the layers and cells of air affects sound propagati... |
[
"Do spiders have concept of memory / facial recognition?"
] | [
false
] | bit of a story Last week I noticed a spider on the side of the house. I didn't kill it because they the small ones that kill little insects. Then one day i took out the step ladder which was apparently connected to the webs and accidentally destroyed parts of the web, i say sorry and go on to do my task. I came back th... | [
"Likely they remember that they made a web and it was partly dismantled so the next one is built differently to try to avoid a similar result.",
"That assumes that it's the same spider.",
"I am pretty sure that the spider is not out to get you.",
"Don't take any chances though."
] | [
"Almost certainly not. Humans are far and away the best at recognizing human faces, but our facial recognition abilities are solely because we have dedicated neural hardware for facial recognition. We have an area in our brain that's commonly called the fusiform face area, or FFA. Damage to the FFA will immediately... | [
"Most insect brains really don't function in the same way that humans and other mammals do. They have ganglia, clusters of nerve cells all throughout their body, that can act somewhat independently of the main brain. This is what makes the legs of dead bugs twitch even after their brain has stopped functioning. ... |
[
"Would farting on an open wound cause an infection?"
] | [
false
] | null | [
"Hi JTJones22 thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the follo... | [
"Human Body"
] | [
"‘Human Body’"
] |
[
"How do neurons support parts of the cell that are far from the nucleus of the cell such as the axon?"
] | [
false
] | Or are distant parts of the neuron supported by neighboring cells. | [
"Great question!",
"Dynein",
" and ",
"Kinesin",
" are two motor-proteins that transport cargo to and from the cell soma (where the nucleus is) and the axon terminals. They move along ",
"microtubules",
" that make up part of the cytoskeletal structure that shape cells. They can transport proteins for n... | [
"It's crazy to think that one cell can transport proteins within itself when a neuron can be almost a meter long!"
] | [
"Those bad boys can become even bigger! ",
"Dopaminergic neurons from the pars compacta of the substantia nigra are 4.5 meters/15 feet on average",
". They're also the ones that die in Parkinson's, so unfortunately there may be a downside to the exceptionality."
] |
[
"Question that's always bugged me – color as linear and cyclical"
] | [
false
] | Note that the following has no basis in anything other than my own scattered knowledge of the subject and my very well rely on incorrect assumptions. We commonly think of the color spectrum as being cyclical, as on a color wheel or a standard . Here each color blends continuously into the next color, giving us the ide... | [
"We had some discussion of this in a ",
"previous post",
", but remember that colors do not have to be monochromatic and fit in the spectrum. No where in the linear electromagnetic spectrum can you find a wavelength that is purple in color- this is because purple is what your brain see when you have both red li... | [
"My only additional note is on how this happens: we only have 3 types of cones (red, blue, green), and each one responds to a certain magnitude as a function of the wavelength it receives (see ",
"here",
"). So we only perceive light in 3 dimensions, hence the 3-sided representation of color that you learn abou... | [
"argonaute gave a nice description of why this happens, but I'd like to add ",
"this diagram",
" which is a nice way to visualise what you are asking. It shows how colours map to the spectrum, and how purple completes the loop by blending red and blue."
] |
[
"When did sleep evolve?"
] | [
false
] | From my understand of evolution, if many species share a similar trait (IE. Eyes) it means that it either evolved a very long time ago in a common ancestor or is an example of concurrent evolution. Since most animals seem to sleep, even fish, this would mean that sleep has been around for a very long time. Do we know h... | [
"most animals seem to sleep, even fish, ",
"Even Jellyfish have a sleep-like part of their day(night):",
"http://www.mja.com.au/public/issues/181_11_061204/sey10757_fm.html",
"In the last jellyfish season, we managed to track several tagged box jellyfish (Box 2), and came up with some staggering results. It s... | [
"even plants have a circadian rhythm.",
"Wikipedia on Circadian Rhythm"
] | [
"I imagine it was VERY early on, and that it was a mechanism that helped save energy during the time that the organism was unable to feed/photosynthesize."
] |
[
"Is there any truth of being able to detect storms from pain in joints?"
] | [
false
] | [deleted] | [
"In support of this, I felt it worth mentioning that barometric (pressure-based) storm forecasting was pretty much the only game in town until telegraphs (and perhaps more importantly, radio) made it possible to quickly gather remote weather data. Robert Fitzroy (the captain who sailed ",
" to the Galapagos whil... | [
"In support of this, I felt it worth mentioning that barometric (pressure-based) storm forecasting was pretty much the only game in town until telegraphs (and perhaps more importantly, radio) made it possible to quickly gather remote weather data. Robert Fitzroy (the captain who sailed ",
" to the Galapagos whil... | [
"http://skeptoid.com/episodes/4188",
"Like taking Vitamin C to cure a cold, this is another medical myth that is so deeply ingrained that it's really hard to shake. For most of my life I believed my bum knee could predict weather changes. I thought it worked like a barometer. I was unaware that simply riding in a... |
[
"If our brains are run with electricity, why don't EMPs knock our brains out?"
] | [
false
] | [deleted] | [
"EMP's work by inducing a voltage in electronics, causing them (especially sensitive electronics like computers) to break.",
"To induce a current in a wire, there has to be some kind of energy input. If you have a normal magnetic field (eg- a normal magnet), you have to input energy in the form of movement to cre... | [
"It works in the exact same way as described above. Neurons are essentially long wires, and a transient magnetic field creates the fluctuation in the field to induce a current along the axons. Normally, your brain creates the current along the axons through the ",
"action potiental",
", which is a cascade of ... | [
"The effect you experience at ultra-high field is actually vestibular, and as I understand it is due to the fact that the fluid in your ear canals is minutely paramagnetic due to the salt it contains."
] |
[
"Does a large magnetic field repel air?"
] | [
false
] | Meaning, if you had a vary large magnetic field being produced by a coil. wouldnt the large magnetic field repel other electrons in the area? so if there was air, wouldnt the electric field being pushed out from the wire make the air be pushed away from the wire? Edit: Look up "Coil Gun' or go to this: This is what I m... | [
"Nitrogen is slightly diamagnetic and oxygen is slightly paramagnetic. A strong enough magnetic field will repel nitrogen and attract oxygen. ",
"Air being a mostly non-ionized gas is electrically neutral and has almost no magnetic moment. "
] | [
"Basically, a field strong enough to attract air would attract a buttload of other stuff wayyy earlier like ",
"frogs",
" or ",
"strawberries",
"Everything with mass is magnetic to a degree."
] | [
"Nitrogen is slightly diamagnetic and oxygen is slightly paramagnetic. A strong enough magnetic field will repel nitrogen and attract oxygen. ",
"I'd imagine a field strong and stable enough to cause strong separation of atmospheric nitrogen and oxygen would cause all sorts of other, weirder effects. "
] |
[
"With Pluto's orbit crossing Neptune's, is it possible for the two of them to collide in the future?"
] | [
false
] | [deleted] | [
"No. See ",
"this",
" from NASA.",
"Although Pluto can get closer to the Sun than Neptune is, given its particular (tilted) orbit, Pluto's orbital path never actually intersects Neptune's orbital path."
] | [
"There was a good ",
"CrashCourse video",
" last week that spoke directly to this point. ",
"As ",
"/u/fishify",
" said, Pluto and Neptune's orbital paths never actually intercept. Even if they did, the 3:2 ratio of orbital periods means the two will never meet at the intersection as pointed out in the ... | [
"Further, Neptune and Pluto are locked intoa resonance orbit which is very stable and not likely to change so that they WILL collide. That they may have come close to collision in the past is seen by the retrograde orbit of one of Neptune's moons, Triton; the highly eccentric orbit of Nereid; and a current eccentr... |
[
"Why does global warming make certain areas colder than usual?"
] | [
false
] | I ask because I see a friend from high school post "There are people complaining about global warming...its April 8th and there is a winter advisory in place?" So why is global warming making certain areas, in this example Wisconsin, have such sporadic and cold temperatures this year? | [
"It's called \"climate change.\" ",
"On average, the global temperate rises, hence the name Global Warming. What's actually happening is we are seeing increases of extreme weather events. That can mean bitter cold winters or massive hurricanes or blistering heat waves. ",
"Higher global temperatures (again, ave... | [
"Okay I think I understand that, so say the Earth in 1950 has 100 thermal energy (made-up term to help me think through this) and that energy gets distributed to different climates and places to make places hot or cold. So say if Asia's climate has a hotter than usual season, then other places around the world woul... | [
"That's one way to look at it.",
"The idea of a \"net sum\" in thermal energy is obviously not entirely correct, but it's a good way to visualize things. Just because Place A in Asia has a hot summer doesn't mean Places B, C, and D ",
" to be colder to offset the energy in Place A. Those places could also have ... |
[
"If you had one ice pack, where would you place it on your skin to optimally lower your body temperature?"
] | [
false
] | My theory is that you would place it on a vein near the surface of your skin, for instance, the jugular. Blood passes through there and it seems that would distribute colder blood throughout your body. I thought this might come in handy if someone ever was affected by a heat stroke. | [
"Great minds...",
"http://www.reddit.com/r/askscience/comments/jfchk/if_youre_overheating_what_is_the_most_efficient/",
"Top answer: ",
"The three best places for an ice-pack would be the sides of your neck, under your arms, and in your groin area. This allows you to cool your carotid, brachial, and femoral a... | [
"Unless the goal is to cool the brain as quickly as possible, in which case the neck would probably be the best answer."
] | [
"Why would that not make sense then? You are trying to cool your body temperature overall, not outgoing over inbound blood particularly.",
"I would imagine the answer would simply be \"whatever point has the highest contact area\" in the end though. Probably the armpit or groin simply so there would be no or litt... |
[
"How do multifocal Intra-ocular lenses work?"
] | [
false
] | null | [
"Thank you for the above. What I don't understand about the multifocal is this: Since it is sewn into your eyeball, and it moves when your eyeball moves, how can the diopters change when you look (move your eye) up or down? "
] | [
"Thank you for the above. What I don't understand about the multifocal is this: Since it is sewn into your eyeball, and it moves when your eyeball moves, how can the diopters change when you look (move your eye) up or down? "
] | [
"Thank you so much for that explanation. It helps, but I am still not totally clear on it and I don't think I will be until I can see a diagram. But let ask you this: Does the light shine on different parts of the retina for the differing diopters, so your brain can choose the correct one? "
] |
[
"Where do green plants like spinach get the high levels of iron contained within them from?"
] | [
false
] | null | [
"Almost all of the iron in spinach (or any plant) is absorbed by the roots from the soil.",
"Basically plants have to take up iron in ionic form -- not elemental form. The ionic forms of iron are Fe2+ (ferrous iron) and Fe3+ (ferric iron). To help this along, their roots will pump out acid and chelators into the ... | [
"They are molecular cages that surround a compound in a solution (like the watery environment outside of roots, or in a cell cytoplasm, in this case.) They can help make a compound more soluble, or prevent it from doing the harm to the cell that leaving it free would cause. Free Iron is toxic, so in the case of pla... | [
"They are molecular cages that surround a compound in a solution (like the watery environment outside of roots, or in a cell cytoplasm, in this case.) They can help make a compound more soluble, or prevent it from doing the harm to the cell that leaving it free would cause. Free Iron is toxic, so in the case of pla... |
[
"Is the vapor from a liquid in equilibrium hotter than the liquid itself and if so does that violate thermodynamic principles?"
] | [
false
] | In an adiabatic container, if you put a liquid there, at certain pressure there would be some particles with enough kinetic energy to overcome the inter-molecular forces and escape. So the gas must be made only of particles with high energy so the temperature must be higher. Summing up, what would happen is that an ob... | [
"You are describing evaporative cooling, but if you have a closed system in equilibrium, just as many vapor particles will be condensing as liquid particles entering the vapor phase, so there is no net heat transfer. "
] | [
"By definition of equilibrium. The air above the liquid phase gets more and more saturated with vapor until the rate of condensation equals the rate of evaporation."
] | [
"Essentially the chemical potential of species A in Vapor phase equals the chemical potential of species A in liquid phase"
] |
[
"How long would we last if the sun went out, just hours or days?"
] | [
false
] | Lets say some voodoo magic makes the sun stop giving out light. How long would it be before earth couldn't sustain animal life? How long before it was frozen solid? I'd assume the oceans would be the last places to support life because it would take a few weeks/months for them to give off their heat. | [
"\"Within a week, the average global surface temperature would drop below 0°F. In a year, it would dip to –100°. The top layers of the oceans would freeze over, but in an apocalyptic irony, that ice would insulate the deep water below and prevent the oceans from freezing solid for hundreds of thousands of years. Mi... | [
"Life would still exist near hydrothermal vents as long as they remain active, which could be a very, very long time."
] | [
"Molten core?"
] |
[
"What will happen to the James Webb Space Telescope after the fuel has run out?"
] | [
false
] | I understand it was set for 5 year mission which will be extended due to extra fuel not used for corrections, but what will happen at the end of this mission? Will it be deliberately deorbited / crashed into the moon? Or is there a possibility that they could prolong the mission somehow, just not in L2? | [
"Specifically about JWST, I haven't found any official sources. It's possible that they haven't even decided yet.",
"More generally, spacecraft at Lagrange points become unstable when they run out of fuel. If left on their own, they can come down to Earth to burn in the atmosphere, or they can drift into a helioc... | [
"There was an AMA here recently. ",
"No refuelling planned or possible. Hardware does not exist. End of story."
] | [
"I worked with Herschel, a far-infrared space telescope run by ESA that was also placed at L2 (and which was, until JWST, the largest telescope ever put into space). When telescopes at L2 reach the end of their lives, they generally use a bit of fuel to push the telescope out of L2, and into a regular solar orbit (... |
[
"Was scurvy a regular occurrence for people on land before citrus was introduced to Europe?"
] | [
false
] | [deleted] | [
"Citrus was used aboard ships because it kept well. Lots of fruits and vegetables have vitamin C, they just tend to rot quickly so were not a part of the diet on ships."
] | [
"There are many vegetable sources of Vitamin C.\nRed Peppers and Brocolli contain considerably vit-c more than oranges, for instance.",
"http://en.wikipedia.org/wiki/Vitamin_c#Plant_sources"
] | [
"you are correct, however red peppers were introduced in Europe much later than citrus fruit. but broccoli was indeed already present, as were lots of other vitamine-C-rich fruits & veg."
] |
[
"Does filtered water evaporate faster than tap water?"
] | [
false
] | When I fill the water bowl for my cats (haha yeah I know), the water seems to go faster when I use filtered water from the fridge than water from the bathroom tap. I'm not sure whether it's because the cats prefer filtered water, or because filtered water evaporates faster. | [
"there isnt enough difference in the composition of Filtered tap vs tap water to facilitate any change in the evaporation rate. "
] | [
"Yes, the evaporation rate will be affected by what's dissolved in the water, but this is probably not the biggest factor contributing to the different (perceived) evaporation rates. As you mentioned, it's possible your cats simply prefer one over the other -- this wouldn't be surprising, since humans generally do ... | [
"Anything that interferes with the hydrogen bonding in water will result in faster evaporation. Filtered water would evaporate slower , but the ion/solute concentration in tap water is probably not large enough to make a noticeable difference. "
] |
[
"How does snake/spider poison affect the human body?"
] | [
false
] | [deleted] | [
"The most common coagulopathy associated with snake envenoming worldwide is venom-induced consumption coagulopathy (VICC), which results from activation of the coagulation pathway by snake toxins including thrombin-like enzymes, prothrombin activators, and factor X activators. ",
"source",
"More info on coag ca... | [
"This ",
" shows the effect of Russel's viper snake venom on blood. Quite amazing."
] | [
"So, i have always wondered. If some one is bitten by a venomous animal and their breathing and heart stop because of neurotoxin, can that person put on machines until the toxin is flushed? Pump; the heart and lungs until the poison is gone? Or will other things start to break down? "
] |
[
"Where did the water on Mars go?"
] | [
false
] | More and more evidence is piling up that there was once water on Mars. So where did it all go? | [
"You're right, there's pretty conclusive evidence that there was once liquid water on mars, and most likely quite a lot of it. One look at a ",
"topographic map",
", and you can tell that the Northern hemisphere is quite a bit lower than the Southern, and a lot more crater-free. Moreover, there appears to be a ... | [
"Are you asking about liquid water? The pressure on Mars is too low and thus liquid water would quickly boil away into water vapor. There is still water on mars, most of which is located in the polar ice caps. Trace amours of water vapor are also found in the atmosphere. ",
"http://themis.asu.edu/node/5392",
"\... | [
"Yes, that will have an effect...but honestly, people tend to overemphasize the importance of a magnetic field as a key element in maintaining an atmosphere. A magnetic field can only block some charged particles; neutral particles, high-intensity photons, and cosmic rays can still erode away the upper atmosphere, ... |
[
"If there are an infinite amount of points between one and two, then how many points are between one and 3?"
] | [
false
] | Me and my friend have been having a debate on this matter and I want to know the truth! Or the theoretical answer. Is there more infinity, or the "same amount" of infinity. Thanks! | [
"The same amount of infinity",
"When dealing with infinite sets, the meaning of the phrase \"how many\" needs a little clarification. What we mean when we say two sets are \"the same size\" (in this context) is that they can be put in \"one to one correspondence\". That is, for every thing in the first set, we ca... | [
"Actually, it's ",
" the same infinity."
] | [
"Actually, it's ",
" the same infinity."
] |
[
"Assuming I am on the same spot on earth. How far is my current position away from my position 365.256363 days ago?"
] | [
false
] | I imagine precise calculations of planet orbits use center of mass of solar system as the coordinate origin. Let's also do that here. What would be the major contribution of the movement? Perturbation from the moon? I am satisfied with an order-of-magnitude answer. As a blind guess, anywhere between 10m to 1000km seems... | [
"Relativity says that there is no such thing as \"the same place\" at different times, anymore than there is \"the same time\" at different places. We can choose a coordinate system that gives the answer zero, but we can choose coordinate systems that give ",
" answer we want, though the \"reasonable\" ones with... | [
"the great thing about science is that asking questions actually makes you smarter. that's a nice way of saying we don't know for sure. and here's why:",
"you may be standing on the same patch of earth as last year, but if we use the center of the sun (as the OP suggested) and a set of fixed stars (very distant ... | [
"In terms of Earth's scale, you'd be surprised: ",
"http://upload.wikimedia.org/wikipedia/commons/0/0c/Solar_system_barycenter.svg"
] |
[
"Is there a difference between setting a phone to full volume and the speaker it's connected to at half and vice-versa?"
] | [
false
] | Whenever I connect my phone to my car speakers, I always put it at max volume and play around with the car volume. Is there a difference in output quality or mixing if I set the phone to half volume and doubled the speaker volume? | [
"It has to do with the hardware circuitry. All circuit components have minimum and maximum operating conditions. They are subject to errors such as voltage drift, voltage ripple, phase distortion, etc. The maximum operating conditions are just that, the absolute maximum environment in which this thing will work... | [
"The ideal scenario for the most distortion free signal with the best signal to noise ratio is to set both at about 70% max power. ",
"So set your phone at 70% and adjust your car setup for loudness, but not past 70%. I can go into the specifics of why that is if you're interested. "
] | [
"Likely because the audio mixer on the phone is clipping the sound when it's at max volume. It'll only be capable of outputting up to a certain amplitude, and the sound system in your car can then amplify it further (as it has a higher limit).",
"To the OP: As long as you keep both devices below their clipping po... |
[
"Is it really possible to \"waste\" water?"
] | [
false
] | null | [
"This is, at the core, a thermodynamics question.",
"You probably know about the law of conservation of energy, that is, that \"energy cannot be created, nor destroyed\". Because of the second law of thermodynamics, the energy conservation law can be amended to read: \"energy cannot be created, nor destroyed, it ... | [
"What you waste is clean water. Drinkable water. Usable water.",
"When you drink water and piss/sweat/cry/spit it out, it needs to be processed to make it 'useful' water again. We can only do this so quickly, and it obviously costs money."
] | [
"I live in Africa in an area that gets 450mm (18 inches) of rainfall a year. We have rivers, but they are (a) not very big, and (b) filled with more human waste than you could believe. You can't just fill reservoirs from them without a substantial cleaning process. There's not enough rainfall to provide the 50 odd ... |
[
"Would it be possible for things to be ripped apart by gravity?"
] | [
false
] | [deleted] | [
"The people would be pulled by both planets simultaneously. If the planet they were on had the stronger pull, they would stay there. If the planet they were not on had the stronger pull, they would be pulled to that planet. If the forces were equal then it would be the same as there being no gravity at all, and the... | [
"Yes, it is possibly for something to be ripped apart by gravity. This requires an incredibly sharp gravitational gradient, however. This is not common; tidal forces decrease by 1/r",
" Near the surface of a white dwarf the tidal force on a rope weighing 1kg and 1m long is only about .24 N. Near neutron stars and... | [
"They'd still be pulled to the planet they were on, although much less strongly (the force acted by the planet they WEREN'T on would essentially subtract from the force acted by the planet they WERE on), provided that the planets are of similar mass. Although the planets would presumably collide, being so close. "
... |
[
"How does Phosphorus Glow Powder change, chemically and/or physically, as time goes on?"
] | [
false
] | This much I do know, you can charge phosphorus glow powder with really any form of light but it is best done with UV. What I want know precisely is: 1) What is reacting with what to produce a glow? 2) Is it radioactive? 3) Why is it brightest at ~10 minutes, but can still last as long as ~30 hours? 4) Why is UV lig... | [
"A UV photon will excite the electron and then it will go through one or more intermediate transitions, emitting low-energy photons that you can't see, before the transition that emits visible light.",
"It's been a while since I touched photochemistry but I'm fairly sure intersystem crossing is nonradiative. The ... | [
"There is no chemical or nuclear reaction occurring in a ",
"phosphorescent",
" material. Absorbed light excites electrons to a higher-energy state, and light is released as those electrons return to their ground state. This is very similar to ",
"fluorescence",
", but the difference is that the transition ... | [
"Correct -- the ISC is a non-radiative transition."
] |
[
"Why does metal feel colder than wood even if they're the same temperature?"
] | [
false
] | I know that it's because metal conducts heat better than wood, and that this difference in conductance is related to the conductivity of electrons in the material. My question, however, is about the microscopic mechanism of this event. Some valence electrons in metal flow about freely, but not in wood. What about the d... | [
"In a metal, atoms are arranged in a ",
"crystal lattice",
" which allows electrons to [more] easily pass between atoms. In wood, atoms are arranged in a haphazard fashion, usually in distinct \"chunks\" because wood is a composite material.",
"Going back to the structure of metals, the arrangement of atoms ... | [
"There are two effects here that are important to decouple.",
"The first is that when you touch something to check its temperature, what you're actually checking is the temperature of your fingers in contact with that object. So lets say you touch a piece of metal, it feels colder than wood because metal conducts... | [
"It's also about the size of the atoms involved and how tightly held their electrons are. In a metal the atoms involved ",
" to be larger, and have less hold on their outer electrons (they are more free to move, creating the \"electron sea\" typically used to describe metals). try ",
"this",
" for a deeper ex... |
[
"Can cosmic radiation trigger neurons in any significant or cognitively noticeable way?"
] | [
false
] | I’m led to understand cosmic radiation can trigger transistors within electronic circuits. Was curious if it could also energise a neural pathway in the brain to any degree | [
"Yes, some of the Apollo astronauts, who were passing through the Van Allan radiation belts reported seeing occasional, bright flashes of light, even with their eyes closed. This is assumed to be caused by radiation penetrating either their retinas, their optic nerves, or their visual cortex, we're not quite sure."... | [
"Couldn't those flashes also be cherenkov radiation? Since cosmic rays are mostly very high energy charged particles, those should create cherenkov radiation when they pass through the eyeball."
] | [
"\"Mechanical pressing your eye can trigger neurons, therefore something completely unrelated should be able to do the same\"? Is that really what you want to say?"
] |
[
"\"Banking\" umbilical cord blood - Is there any evidence that paying a facility to keep your newborn's hematopoietic stem cells is a good idea?"
] | [
false
] | I feel like maybe someday I'll be glad I did it. At the same time, I also feel like maybe I'm being scammed by people taking advantage of my fear and ignorance. | [
"Absolutely",
". Though scientists are making rapid advancement in developing techniques for creating stem cells from the cells of adults, cord blood still appears to be the easiest source of stem cells. Given the future prospects for stem cell-based therapies (hype or not), it seems worth it to keep the options ... | [
"This story really needs proper material to back up its veracity."
] | [
"This story really needs proper material to back up its veracity."
] |
[
"Is it true that humans share 50% of DNA with potatoes?"
] | [
false
] | I'm trying to find a reputable source but can't. | [
"I'm going to expand on your answer a bit.",
"I'm also going to generalize a bit, because some cells in multicellular organisms can be incredibly specific. They can be programmed to do very specific tasks like hold lots of hemoglobin, transmit neurological signals, hold fat etc..",
"Most cells in the world have... | [
"It's a banana actually, but any plant will do. The thing is, these kinds of comparisons are fraught with difficulties, but they still hold a grain of truth.",
"Genes produce proteins and other molecules that build and run cells. The basic machinery of cells as we know them today took about 2.6 billion years to g... | [
"50% is too high. For plants in general it's closer to 20%. ",
"http://ngm.nationalgeographic.com/2013/07/125-explore/shared-genes"
] |
[
"Why was/is it necessary for sperm to exist outside the body (i.e. inside testicles) from an evolutionary standpoint? Why didn't sperm instead evolve to adapt to the temperatures inside the body?"
] | [
false
] | null | [
"That's just the way it went. The proteins used in sperm production operate most efficiently at that slightly lower temperature, and also at a constant temperature. So when some animal way back when evolved a little climate controlled zone for the sperm factories, they made more quality sperm. More quality sperm=mo... | [
"Of course. But the question was whether some mammals had internal testicles; some do.",
"It's a temperature-regulation thing. Any adaptation that made the temperature of sperm better suited for sperm survival would be passed on.",
"Whales evolved from the same ancestors that elephants evolved from, and elephan... | [
"Are there any mammals which produce their sperm within their body? Have there been studies comparing the difference in sperm production/quality of these animals?"
] |
[
"Could something like the Alcubierre drive be used inside a black hole to escape it?"
] | [
false
] | null | [
"Since Alcubierre drive is not based on anything known to science, it is impossible for a scientist to answer this question without speculating.",
"The Alcubierre drive requires negative energy density, which doesnt exist, and then assumptions about what negative energy density would do to general relativity whic... | [
"Ok let me rephrase the question then. Is it theoretically possible to warp the space inside the event horizon so that not all paths lead to the singularity? Im using the Alcubierre drive as the example because it is proposed to warp space and it gives you an easy visual of what im thinking, despite it being fictio... | [
"As far as I know, the answer is no. Once inside the event horizon you can't do anything, nothing will warp space-time in a way to get you our."
] |
[
"When you exercise really hard so your lungs burn and then as a result spend the next 48 hours coughing up your lungs is this good for you (clears out your lungs) or bad for you?"
] | [
false
] | I always assumed this was a good thing? | [
"Exercise is a good thing. Coughing for 48h afterwords is generally not.",
"When one exercises very vigorously for extended periods of time the vast volume of air inhaled dries out the membranes in the lungs which can result in irritation (coughing and burning). To minimize this try to focus on controlling brea... | [
"Huh thanks everyone!"
] | [
"Huh thanks everyone!"
] |
[
"Can someone explain in simple terms what the Large Hadron Collider is and what its purpose is?"
] | [
false
] | null | [
"The Large Hadron Collider (LHC) is a particle accelerator managed by ",
"CERN",
" in Geneva, Switzerland. It's several circular accelerators ring with the largest being 17 miles (27 km) across. Using a very powerful system of magnets, charged hadrons, in this case protons or lead nuclei, are accelerated to ver... | [
"Let's talk about temperature.",
"In ordinary matter under conditions familiar to humans, temperature is just a measurement of the average kinetic energy of molecules. Temperature has an effect on chemical reactions because there is a different amount of ambient energy available at different temperatures, and tha... | [
"Also the storage rings don't produce any net acceleration",
"The LHC is very much an accelerator as well as a pair of storage rings. After the restart it will accelerate the beam from ~400 GeV to ~7 TeV. (The SPS, which injects into the LHC, is only capable of ~400 GeV)"
] |
[
"If a different male sperm reached the egg first, would I look any different? Would I even be me?"
] | [
false
] | So are genetic traits different in every sperm I guess is the question? So sperm 1 carries the big nose gene but sperm 2 carries the good looking gene. (Sperm 1 won BTW). | [
"Yes and no. An allele is basically a specific version of a gene, and they will, with almost certainty, be at least slightly different from each other. You have 2 sets of almost every allele (if you are a guy), one from your father and one from your mother. They each have 2 sets of every allele that they got from t... | [
"Good response; I just have some details to nit-pick. Hope you don't mind. ",
"You have 2 sets of almost every allele (if you are a guy), one from your father and one from your mother",
"First, terminology: you have two sets (alleles) of every ",
". You have two alleles of almost every gene whether you're ma... | [
"Like a lot of answers on this sub-reddit you answer the questions and much more. Thanks."
] |
[
"What happens to your vocal cords when you lose your voice?"
] | [
false
] | null | [
"There is swelling (edema) of the tissues of the larynx (aka the voicebox, which includes the vocal cords). The swollen vocal cords cannot vibrate so well, leading to a hoarse voice or even no voice at all. The swelling of the tissues of the larynx is like having, say, wet towels draped over your drum kit, greatly ... | [
"Woah that's pretty crazy thanks for the info though"
] | [
"This is spot on.",
"Losing your voice is a symptom of a swollen larynx, less than a disease itself.",
"If you want to minimise swelling, avoid talking too much, avoid shouting or whispering, and use an antiinflammatory medicine."
] |
[
"Can you observe a black hole growing?"
] | [
false
] | It's been a while since I took my GR classes, but this recently occurred to me: So, you can't observe something crossing the event horizon because of the 1-2M/R that turns up in the metric means it takes infinite time to cross when R=2M. So it appears that all infalling material is distributed across the event horizon?... | [
"Yes, absolutely.",
"How do we measure the massof something? Gravitationally, we look at the orbits of things about it. This is how the mass of the BH (candidate) in Sag A* is inferred.",
"Imagine what would happen if a million solar masses on a radial trajectory fell into the BH in Sag A*. What would happen? W... | [
"If the black hole was in front of a dense field of stars, won't I see a schwarzchild radius black circle?",
"There aren't any fields of stars that dense.",
"Or am I being too loose in my terminology here? i.e. instead of \"event horizon\" I should be talking about \"schwarzchild radius\"?",
"Eh. The two term... | [
"Well, I dunno.",
"Yes, you can measure the mass of the system. But is that necessarily the same as measuring the size of the event horizon?",
"i.e. can you differentiate between something that has almost formed a black hole, and a true black hole?",
"From what RRC is saying, I think the idea is that you ",
... |
[
"Why does water flow out in a twister when I drain the bathtub?"
] | [
false
] | [deleted] | [
"You can visualize this with a thought experiment.",
"Imagine that the water in the tub is not 100.00000% still before you open the drain.",
"Now sit atop a microscopic skin flake that is moving with this not-still water, in a random direction, not straight to the drain. Say you are moving to the right of the d... | [
"forget the folklore about south/north of the equator; that effect is too minuscule to make a difference",
"The effect is smaller than other considerations, yes, but if you can get rid of them, ",
"the Coriolis effect is indeed observed",
"."
] | [
"A tiny bias of the general movement of the water towards one direction is \"amplified\" because as the rotational (angular) speed is accelerated by the decreasing radius (closing arms spinnining on an office chair, angular momentum), the fluid \"drags\" more fluid to the same rotation direction. This is a positive... |
[
"Why can’t DNA replication be done outside a cell ?"
] | [
false
] | null | [
"I'm not sure I understand your question, but we can and do reconstitute DNA replication ",
" using purified proteins. In fact, just during the last several years, researchers have successfully reconstituted the entire eukaryotic replisome (",
"source",
")."
] | [
"https://en.wikipedia.org/wiki/Polymerase_chain_reaction",
" ?"
] | [
"It most definitely can be done."
] |
[
"Do animals with shorter life expectancy evolve quicker?"
] | [
false
] | Humans live for about 80 years, lab rats (Sprague Dawley rat specifically according to ) live for about 3 years. So, in one human life span, you can have about 35 generations of rats. Does evolution work in steps, such that you could see small changes in a line of rats? | [
"It's not life expectancy but generation time that's important. Some bacteria have a doubling time of ~20 minutes. In a sense, these types of organisms are the most evolved form of life that we know of.",
"I use \"most evolved\" advisadly. It's not a term I like, but it's handy shorthand."
] | [
"It also requires a mutation rate. If there is not mutation then generation time could be milliseconds and you wouldn't get evolution. A bit pedantic but I don't want someone using only generation time as a measure, since it should be generation time*mutation rate."
] | [
"Good point, thanks."
] |
[
"If light has no mass, then how is it affected by the gravity of a black hole?"
] | [
false
] | If light has no mass (which is how they go the speed of light, which is the fastest velocity possible) then how can it be 'sucked in' by a black hole? Wouldn't gravity have no effect on massless objects like light? | [
"Two ways to think about this:",
"(1) anything with energy is affected by gravity (rest mass is just one form of energy)",
"(2) gravity is a curvature/distortion of space-time, so light follows paths that reflect the presence of the black hole."
] | [
"The full equation is E",
" = (mc",
" )",
" + (pc)",
"E=mc",
" is only for objects at rest. Once it is moving, you use the first equation. And since light has no mass, the equation for the energy of light is really just: E=pc (I basically just crossed off the \"(mc",
" )",
" part and then square root... | [
"Because \"gravity\" is nothing more than an observation that space is bent and distorted. So something traveling through the bent space will take paths which appear bent to you.",
"And something traveling has energy, if it is something traveling."
] |
[
"Why is wind or any moving air colder than non-moving air?"
] | [
false
] | If the wind particles are moving with more kinetic energy, shouldn't they be hotter than the non-moving air? | [
"The reason is forced convection (i.e wind) is a much more effective way to transfer heat than natural convection (via buoyancy) or only conduction. This is the same reason blowing on your hot soup cools it faster, the dE/dt is simply much greater as \"fresh\" air is constantly being blown over the hot surface rath... | [
"This answers the question \"Why does wind or [...] ",
" colder than...\". If this was what OP meant then cool. Just a notion: Moving air in a sauna feels prettty hot!",
"There's a twist to the soup thing, by the way. When air is still, a layer of moist air forms above the surface. When you blow it away, new wa... | [
"Great nuance. Heat transfer is a rich topic."
] |
[
"Difference between Gallium Chloride and Gallium Oxide?"
] | [
false
] | Also, I've seen products such as disappearing spoons Made of Gallium. What type do they use and are these products dangerous? Thank you. | [
"Those spoons use metallic gallium - not a chloride nor an oxide."
] | [
"Thank you. I feel rather dumb.",
"Do you happen to know any health risks in dealing with Gallium or somewhere I can research that?"
] | [
"You'll have to look at the MSDS for the particular product. ",
"Here is one from Sigma Aldrich",
". The main concern is ingestion and exposure to mucous membranes."
] |
[
"If I am vaccinated against the flu, can I still pass it on?"
] | [
false
] | I understand that a flu vaccine causes antibodies to develop against the flu. I was wondering if you can still contract and spread the flu if you are vaccinated. I tried to google this, but I couldn't find any credible information. Thank you! | [
"Influenza vaccination is not ",
", meaning that it protects against disease but doesn’t completely prevent all infection - though it does reduce shedding dramatically. This is mostly demonstrated with laboratory animals, because the best way to show it is to actually infect vaccinated volunteers. There are some ... | [
"Thank you for sharing!"
] | [
"We don’t know if COVID vaccines will be sterilizing or not. ",
" viral vaccines ",
" sterilizing, or close to to - smallpox, measles, mumps, rubella, polio, etc etc. ",
"Influenza is always an exception to other viruses. Because it’s an exception, it’s exceptionally important, so people think about flu befor... |
[
"Do gravity waves move at a certain speed?"
] | [
false
] | I was watching the ahow the universe. They were talking about gravity waves coming from a pulsar. I was wandering do gravity waves move at a certain speed? If so how fast do they move are they restricted by the speed of light? Or is it similar to when people talk about the universe expanding faster than the speed of li... | [
"Gravitational waves, like electromagnetic waves, move at the speed of light."
] | [
"You still have the same dispersion relation : c = wavelength * frequency."
] | [
"What about their dispersion relation?"
] |
[
"If Neutrinos can really move faster than light could these particles escape black holes?"
] | [
false
] | null | [
"This seems to contradict one of the most quoted passages from askscience - that suggested that within the event horizon all ",
" point toward the center of the black hole, regardless of how fast you move: ",
"http://www.reddit.com/r/askscience/comments/f1lgu/what_would_happen_if_the_event_horizons_of_two/c1cui... | [
"Much (if not all) of what we know about black holes stems from general relativity, and if the whole superluminal-neutrinos thing turns out to be correct it's quite a gut check. Scientists would need to go back and re-assess some very fundamental assumptions that go into the formation of relativity and that means ... | [
"The X-ray emissions come from further out than the event horizon, though the exact point of emission and mechanism is unknown. But the general principle is that the matter falling into the black hole needs to shed quite a lot of energy to do so, there are charged particles undergoing intense acceleration, high int... |
[
"Why does holding my headphones ~10cm from my ears make the sound nearly inaudible, but I can walk four meters across my living room without any appreciable change in volume?"
] | [
false
] | null | [
"There are a few effects at work here. The first one is that sound intensity from a point source (i.e. a headphone speaker) decreases as 1/r",
" where r is the distance between speaker and ear. If you ",
"plot this",
", you'll see that the intensity drops off much more steeply near the source (r=0.1) compar... | [
"Ya know, I'm answering many more questions related to introductory physics (which I have taught) than scientific computing. Maybe I should ask for a change in my tag to include \"introductory physics\"..."
] | [
"Well, perceived loudness get's into all sorts of funniness when dealing with different tones and pure/mixed tones. If you would like, you could pick the audio freak's standby approximation of 3db to double power at the speaker, 6db to double the actual signal amplitude, and 10db to double 'preceived volume/loudnes... |
[
"Why do allergens cause an overreaction of the immune system when other foreign invaders (such as the flu) elicit a more measured response?"
] | [
false
] | [deleted] | [
"Have you had the flu? Im not sure I would call that response measured. The immune system isnt conscious and responds in an almost mechanical way to challenge, with tissue damage and organ dysfunction often being the collateral damage to clearing what is perceived as an infection. The extent of of the damage to hos... | [
"It's important to note that allergies have existed well before industrialization although it's definitely gotten worse since. Also, the immune mechanisms in allergies often differ from those for the flu, for example type 1 hypersensitivity which is responsible for pollen and animal allergies is mediated by mast ce... | [
"Fair shout. The immune system is all about balancing opposing signals, and industrialization only tips the balance a little, it isnt a primary cause per se. ",
"Also you are right that the type of immune response is very different for most allergies vs most viruses, though both can be severe or mild."
] |
[
"What's underneath deserts?"
] | [
false
] | If I were in a desert (I'm mostly asking about the sandy deserts, like the Sahara), and dug down, what would be underneath the sand? Would I just eventually hit a layer of rocks? Or would there be a layer of soil? EDIT: To clarify, I'm mainly asking if there would be any kind of transition, or would you just hit a la... | [
"Sand is a kind of soil, and if you dig down far enough you'll eventually hit rock wherever you are on the Earth."
] | [
"When I was in Saudi Arabia during Desert Shield/Storm we had to dig a bunker outside our sleeping tent to ditch into in case a SCUD was inbound or something. Some people were designated to go to the perimeter and others would go into the bunker.",
"We got down about 2 feet into the sand (actually it was more li... | [
"How deep is the sand?"
] |
[
"Why does the 1st Ionisation Energy NOT decrease between Group 1 and Group 2 elements?"
] | [
false
] | So I've read that, between the Group 5 and Group 6 elements of the same period, the first ionisation energy because in group 6 the electron is removed from a full orbital, so the mutual repulsion of the two electrons in the orbital makes it easier for the electron to be removed. However, surely this scenario is the sam... | [
"Goig from group 5 to 6 you’re going from s",
" p",
" , a full s and half full o orbital, to s",
" p",
" where you have extra pairing energy from the two paired electrons. Pairing energy for electrons is destabilizing so it takes less energy to remove the 4th p electron. You’re also losing the extra stabili... | [
"Just to clear this up a bit, I think ",
"u/ThatCosmicGuy",
" is referring to the old style groups VB and VIB (nitrogen, oxygen) rather than the modern groups 5 and 6 (vanadium/chromium).",
"The drop in ionization energy in moving from nitrogen to oxygen or phosphorus to sulfur relates to what user ",
"u/ra... | [
"In group 5-group 6, you have an exception to normal electron configuration pattern. We would expect both vanadium and chromium to have a full 4s orbital and a partially full 3d orbital. Vanadium would have 3 electrons in 3d and chromium would have 4, respectiveily. But that's not what happens. Instead, chromium ha... |
[
"How much lower were sea levels during the ice-age?"
] | [
false
] | I'm assuming much lower due to all that water being tied up in ice-form... Am I wrong? | [
"During the last glacial maximum ~19,000-23,000 years ago the ocean was between 120 and 140 meters (390-460 feet) below its current level. ",
"http://web.me.com/uriarte/Earths_Climate/9._The_Last_Glacial_Maximum.html",
"http://shadow.eas.gatech.edu/~jean/paleo/Lectures/Lecture_9.pdf"
] | [
"You're right. I assume by \"ice age\" you mean the most recent one, which ended a little over 11,000 years ago (where the last of the sheet glaciers retreated to high latitudes). During the peak of this particular ice age, sea levels were about 130-140 meters lower than today. Both of these articles are great for ... | [
"Makes you think about where \"cities\" might be underwater huh."
] |
[
"What would NASA's protocol be if we found living insect-sized organic life on Mars tomorrow?"
] | [
false
] | null | [
"Probably not too different from what it is now. ",
"In the same way that invasive species can destroy ecosystems on earth, NASA takes precautions to prevent the transfer of terrestrial organisms to other planets, which could out compete and destroy native Martian life, or going the opposite way by introducing Ma... | [
"As you can see ",
"here",
" we haven't always done a great job of sterilizing our spacecraft. Pieces of the Surveyor 3 spacecraft were collected by the Apollo 12 astronauts and when studied back on earth bacteria that went up with the probe were found still alive inside of it."
] | [
"I'm not sure if you would know this, but what are the potential consequences of contaminating other planets with ",
" potential for life? I mean is there a reason why we aren't doing it even purposefully? I'm saying that because so far we haven't found evidence of life outside of earth. Wouldn't it be ",
" to ... |
[
"Why do we not have a Machine that Checks Serotonin Levels?...Like Glucometers that check Blood Sugar Levels?"
] | [
false
] | People who suffer from Depression have told me that would love to have a machine that they could check their Serotonin Levels during the day. Are there machines available to do that? | [
"Is there a certain level of serotonin we should have? Or is it dependent on the individual?"
] | [
"Question: in your opinion, would it be more helpful to base a diagnosis of clinical depression on physical data (serotonin levels, other biochemical or physiological markers I don't know about), rather than clinical interpretation of behaviour and self-reported psychology?"
] | [
"Question: in your opinion, would it be more helpful to base a diagnosis of clinical depression on physical data (serotonin levels, other biochemical or physiological markers I don't know about), rather than clinical interpretation of behaviour and self-reported psychology?"
] |
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