title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"I dream so vividly every night that I wake up distraught every morning, how can I fix this?"
] | [
false
] | null | [
"We don't offer personal advice of any kind here."
] | [
"Hello,",
"We can't advise you about this here."
] | [
"Oh sorry, why's that?"
] |
[
"Why is it that a glass pane is see through but when you look at it from the side its an opaque green?"
] | [
false
] | I'm wondering why it is that when you look at a glass pane its see through only through a certain direction. When you look at a glass pane from the side there is that opaque green tint. Similarly, if you look at rock of glass do the properties still hold, or is the opaqueness an artifact of being machine shopped. Thank... | [
"The green tint is from ferrous oxide in the glass. The short answer is that the glass is too thin to normally see the color, but looking through the edge of the glass means you are actually looking through more glass, which means more absorption of light by the colored ions in the glass, which means the color app... | [
"From: ",
"http://en.wikipedia.org/wiki/Glass#Color",
"Ordinary soda-lime glass appears colorless to the naked eye when it is thin, although iron(II) oxide (FeO) impurities of up to 0.1 wt% produce a green tint which can be viewed in thick pieces or with the aid of scientific instruments.",
"So basically glas... | [
"OP is asking if a solid chunk of glass, as opposed to a thin pane, would have the same effect. By your explanation, I'm guessing it would."
] |
[
"Once your sick, how detrimental is it to the healing process is it to be around other people with the same sickness? Does it make it more difficult to get better to be around other people with the same sickness?"
] | [
false
] | My young son is constantly getting sick and then I end up getting sick from him. He then proceeds to rub his snot on my arm and need to be held and cough in my face. Is this slowing down my own healing process and if so, why and to what extent? | [
"If it is the same virus/bacterial illness, not detrimental to be around them. It might increase the load a little bit, but either way assuming you don't have an immunodeficiency you are going to be producing antibodies to your own illness (which carries the same antigens as his). Therefore, if it does slow your he... | [
"My doctor has assured me all this sickness in my son's first years is normal as he is just building his immune system. How would this same situation affect someone with an immunodeficiency? My husband is on a drug that suppresses his immune system. "
] | [
"Well you mentioned that your son is constantly getting sick - if these are severe infections or unusually complicated it would make a doctor curious to test his immune function. If your husband is on immunosuppressants, make sure you are washing your hands (and your son's) frequently before having contact with him... |
[
"How effective is CPR without \"mouth-to-mouth\" air transfer?"
] | [
false
] | Today, my girlfriend had a course in basic first aid, and she was taught CPR, with the only exception that she was told that mouth-to-mouth air transfer is not used anymore. From a physicist undergraduate's point of view, knowing not much about human anatomy, I can say a couple of things. The brain ends up dying during... | [
"The new standard of layman's CPR or even licensed CPR states that there is enough oxygen circulating in the blood stream to keep organs perfused enough to keep hypoxic injury at bay. The #1 priority is high quality chest compressions, ensuring depth and rate are adequate along with proper recoil. Assuming someone ... | [
"Here's some info:",
"http://www.emssafetyservices.com/2016/02/15/so-no-rescue-breaths-with-cpr-right/",
"Compression-only CPR does work, but only for a very specific type of cardiac arrest: Witnessed SCA of an adult or adolescent. Physiologically speaking, CPR with rescue breaths is better overall. In some cir... | [
"Stayin' Alive, or Another One Bites the Dust - both good for CPR rythm"
] |
[
"What are some of the strongest/most famous research articles/studies that support Climate Change?"
] | [
false
] | null | [
"Hi ilikealmondsalot 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 th... | [
"earth sciences"
] | [
"earth sciences"
] |
[
"How does the body react to food after prolonged food deprivation. Will eating even a normal portion of food cause stomach aches or other adverse reactions?"
] | [
false
] | null | [
"Food stimulates the pancreas to produce a hormone called insulin. This hormone has various functions, including lipogenesis (creation of fat) and glycogenesis (storage of sugar in the form of glycogen). Some resources are needed in order to make these processes happen, but a prolonged period of fasting depletes th... | [
"Yeah I recently read this dark story that at the end of WWII a lot of people rescued from the concentration camps died anyway, shortly after they ate the food that was given to them. Cruel world."
] | [
"Does this come into effect with intermittent fasting like OMAD ( 23 hours daily fast) or this comes into effect with much more prolonged food deprivation?"
] |
[
"Would it be possible to calculate the total (historical) carbon footprint of a big festival, like Glastonbury?"
] | [
false
] | Taking into account the vast amounts of power they use, the millions of tonnes of equipment being transported and all the petrol being used in the logistics, the millions of people who’ve travelled to a long-running festival like Glastonbury over the years, and so on. Is there a format for working that out? | [
"You can. People calculate the carbon footprint of big complicated things. But you end up balancing accuracy with effort.",
"You might be able to calculate some stuff using a bottom-up approach. Like you said, direct emissions wouldn't be too hard. Travel emissions would be a bit trickier, but maybe you have loca... | [
"Yes, it's a complex Fermi question. The most productive approach would be in using hedonic analysis to reduce the number of variables. ",
"https://corporatefinanceinstitute.com/resources/knowledge/other/hedonic-regression-method/"
] | [
"Comments like this always make me laugh. You’re not actually answering the question, you’re just using it as an excuse to repeat an opinion. What do you mean by “minimal”? Compared to a giant volcano? I’d imagine a festival produces rather a lot more than say, an individual human? A car? A house? So there is a sca... |
[
"When is the difference between short term and long term memory determined?"
] | [
false
] | I was just thinking that if there's a difference neurologically in the brain there has to be a time when the switch is made physically. | [
"Generelly, short term memory is considered to be the short term storage of information and can (roughly) be thought of ",
"a subset of the working memory",
" (working memory includes active manipulation and maintenance of memory content, but also over short time!).",
"Drawing a temporal line between short te... | [
"What are you meaning with \"moving target\"? Some references would also help me understand your perspective."
] | [
"What are you meaning with \"moving target\"? Some references would also help me understand your perspective."
] |
[
"We can use genetic algorithms to produce flawless simulated biped gaits. Why can't we translate that to robots in the real world?"
] | [
false
] | If we have an accurate virtual physics environment and can replicate the properties of server motors, actuators and materials within it then wouldn't it follow that we should be able to plug the walking algorithm into our real world bot and make incredibly effective biped robots by now? Or is this exactly what they are... | [
"Hi. I'm a roboticst. There are several huge limiting factors: our physical simulations are never perfect and are in fact usually laughably bad. Our ability to sense changes to the robot state are corrupt, delayed, and incomplete. The actual control capabilities of the robot are similarly corrupted by noise, delay... | [
"Yes. The first part of your question refers to \"reinforcement learning\". It has been successfully applied to multiple problems in robotics such as super-human helicopter flight performance. Basically, the robot can directly map fitness to motor torques from multiple attempts and demonstrations. Believe it or not... | [
"Excellent answer, thanks very much for that. It makes a lot of sense and I had imagined it might well be to do with iffy feedback and sensing mechanisms. Very interesting to hear that simulation is actually a hindrance though.",
"A couple of follow ups if you have a minute - are feedback mechanisms likely to get... |
[
"Is it possible that extraterrestrial life forms don't function the way we know life itself? (i.e.: while we're looking for proof of water on mars, could there be a life form not requiring O2 or H20)"
] | [
false
] | [deleted] | [
"Forget Earth, there's ",
"life",
" inside my ",
" that doesn't require oxygen! :) And many bacteria/archaea that don't need (external) sugar, or light, getting chemical energy from compounds in their environment.",
"All life we know of needs water, but nobody's really ruled out that life can't exist with s... | [
"They're trying!",
" ",
"Admittedly, about all he's done is make a basic membrane. But he's got to start somewhere. Seeing as how we can't even make cells using the template that's all around us, it's probably not going to turn into life anytime soon. The important part is that it has been shown that it might k... | [
"Is it possible? Probably, we're not ruling that out. ",
"However, when we search for life it makes more sense to use what we know than what might be. ",
"And, since we ",
" life can exist using carbon and water, and we don't know about any other type, we might as well go with what we know, and be open to oth... |
[
"What Would Dinosaur Meat Taste Like? Seriously. .."
] | [
false
] | null | [
"We don’t know. It’s not quite correct to say that dinosaurs are a lot like birds; birds ",
" theropod dinosaurs. They’re living dinosaurs. However, there is obviously a lot of variation in extinct dinosaurs that we don’t see today. I mean that in terms of higher-level taxonomy and bauplan, because with over 10,0... | [
"Thank you for the reply. I chose chicken as the example because that's what most people tend to compare their meats to. I have had gator before and I actually found it quite similar to chicken. "
] | [
"Hi evilman1085 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 fol... |
[
"What exactly happens when Polyurethane foam is formed?"
] | [
false
] | I am currently doing my mechanical engineering dissertation on making structures using polyurethane foam, I have no background in chemistry and reading through many papers on polyurethane I find them hard to follow sometimes. I have searched through many papers to try and find what is going on but I cannot. Basically I... | [
"Polyurethanes are actually a group of related polymers, so there's no single answer. But typically the foaming comes from the reaction forming a gas that then creates bubbles in the material as it sets. CO2 is the most common gas.",
"Some reactant mixtures will not release any gas, or they might release more gas... | [
"I think this is the answer. Thank you very much for your help. Do you think if i add more water to the bag it would help in this case then, or is it different? "
] | [
"I found this resource by typing \"Polyurethane 2 part foam chemical reaction\" into google (the order is important and not a lot of people understand it)",
"http://www.essentialchemicalindustry.org/polymers/polyurethane.html",
"The quote I found that seems to explain why a vaccum is not generating the results;... |
[
"Why do proposed Covid-19 vaccines have to be stored at very cold temperatures?"
] | [
false
] | null | [
"Mostly they don’t, but some of the early front-runners are mRNA vaccines, and RNA is relatively unstable. It’s those candidate vaccines that may need exceptional cold chains (for example ",
"Another Challenge for Vaccine Makers: Keeping It at Minus-112 Degrees",
"). In general protein-based vaccines like the N... | [
"Complex molecules have a higher chance to denature (basically \"destroyed\") at higher temperatures and because of thermodynamics, it is highly unlikely that it can fix itself. By storing the vaccines as cold as possible, they will last longer."
] | [
"This is one reason I'm glad we'll be getting the Oxford vaccine in my country (assuming a lot lot of successful work to come..). Seems like the delivery mechanism is more mature."
] |
[
"Is there a good, trustworthy resource that covers the history and development of medical pseudoscience?"
] | [
false
] | I've been curious lately of the origin of many of the currently popular alternative medicines like homeopathy, acupuncture, chiropractic, etc... Side note: Is Freudian Psychology (psychoanalysis) a pseudoscience? I remember reading about it's questionable origins, but not sure what the current status is. | [
"NIH provides good objective information about the current status of these topics and encyclopedia.com has good information about their history.",
"Here are those pages for the topics you asked about:",
"https://nccih.nih.gov/health/homeopathy",
"http://www.encyclopedia.com/medicine/divisions-diagnostics-and-... | [
"It's a big help, thank you!"
] | [
"This is more a question for ",
"/r/AskHistorians",
" than ",
"/r/AskScience",
", but in a nutshell: it should be worth noting that serious historians of medicine don't find terms like \"pseudoscience\" to be super useful historically. There aren't easy demarcations between \"pseudoscience\" and \"science.\... |
[
"Seasonal flu has a basic reproduction number (R0) of 1.3 and COVID-19 has a 2-2.5. What factors dictate the difference between these diseases in terms of spread?"
] | [
false
] | For example, does that mean that a smaller amount of COVID-19 viruses are needed to infect a person and gain a foothold in the body than seasonal flu? Also would the shape of the spike proteins protruding from the capsid affect the viruses’ ability to attach to respiratory cells thereby increasing the R0 value? | [
"R0 is the average of how many people one infected person would spread the disease to in an 100% susceptible population. So very similar to infectivity of a disease, not how many viral particles are needed to infect one person. ",
"Stuff that affects a diseases R0 = how long you can be walking around spreading th... | [
"Great comment. Just to add something, it’s important to note that R0 is not completely an intrinsic value. Like omgu states there are social factors and “extrinsic” factors that can be done to lower the R0. For example the R0 in Wuhan for corona may have been drastically different before the lockdown of the city V... | [
"R_0 is a confusing number because it’s not a natural average. In the compartmentalized models (like SIR) it’s always some ratio of the infection coefficient(s) to the recovery coefficient(s) which works fine for an average. But in descriptions and our intuition it sounds a lot like just the infection coefficient(s... |
[
"[Genetics] Are homologous genes on the X and Y chromosomes considered alleles of the same gene?"
] | [
false
] | [deleted] | [
"Crossing over does occur in the pseudoautosomal regions, and they also help pairing the chromosomes for correct segregation during meiosis. Genes in these regions are inherited like autosomal genes, and would be alleles."
] | [
"Crossing over does occur in the pseudoautosomal regions, and they also help pairing the chromosomes for correct segregation during meiosis. Genes in these regions are inherited like autosomal genes, and would be alleles."
] | [
"I wonder if this was something that evolved to promote meiotic alignment for these two otherwise very different chromosomes.",
"Actually these regions are homologous because the X and Y chromosomes were once a homologous pair. The evolution of the Y as a distinct chromosome came about by its degeneration (loss ... |
[
"Is light affected by temperature?"
] | [
false
] | [deleted] | [
"The terms \"cool\" and \"warm\" light refers to the color of the light. Cool light tends towards the blue, while warm light is more red. This stems from colors being classified similarly, probably because fire is reddish and warm and snow is blueish and cold.",
"Physically, blue light is more energetic (and the... | [
"Temperature affects density of matter, and light passing through different densities of matter (eg air/water, warmer air/colder air) refracts light. This is why the heat haze effect is seen. Not sure about your second question."
] | [
"It's the same thing. 'Hot' and 'cold' are just relative statements when talking about temperature. "
] |
[
"What effect of one big workout compared to several small workouts? (throughout the course of a day)"
] | [
false
] | Suppose I have unlimited access to my home gym and wish to do weight training. I could perform one hour long gym session. Or I could perform six ten minute sessions. What would be the differences (in gains, stamina, overall health etc.) between the two methods of training. | [
"Hey guys! Let's keep this on topic and scientific. No bro science please, only documented studies from journals, textbooks, etc. Thank you!"
] | [
"Better do 1 hour workout so your body tries harder when Its already tired. Thats the way to improve. "
] | [
"Yeah, thanks that seems to be the rationale on ",
"r/fitness",
" when I asked this question there. Do you know of any studies on this particular topic though."
] |
[
"genetics and the structure of the brain"
] | [
false
] | ok, so I am somewhat fascinated by the brain and how it works, specifically how it interconnects. I know that the brain stops technically growing at an early age (the nuber of neurons reaches the max) and that most brain "growth" is simply a growth in connections between the neurons. my question is how much of this is ... | [
"It's generally considered in psychology that genes and environment both play an important role but to different degrees in different areas. A way to think about it is that genes tend to give you the outer parameters of what one can achieve or how they will behave and environment will decide where in that continuum... | [
"that makes sense, and I understand I just opened the pandora's box of nature vs nurture, another question more based on non personality traits, such as mental \"skills\" (math creativity, ingenuity etc) do genes provide the upper and lower limits on these traits or do they simply provide a \"resistance\" value whi... | [
"So I studied the intrinsic factors (genetic) that determined the structure of the murine neocortex for about 3 years. If you want to know about how these determine the shape and size of the cortical areas, AMA. I don't know much about psychology though. I stick to the harder aspects of neuroscience."
] |
[
"What causes a razor blade to lose its sharpness?"
] | [
false
] | null | [
"There are two processes at play.",
"Firstly, the edge becomes warped with repeated use so that it is no longer a true straight line. This is why stropping a razor or honing a knife with a steel keeps them sharp. Stropping/ honing makes the ridge that is the edge straight again.",
"The second process is that of... | [
"Thanks, now I know what's the difference in the effect between stropping with leather and sharpening with the stone. I always though that the stone was just the hardcore version of the leather "
] | [
"Does that mean that bits of metal from knives can end up in food from cutting food stuff?"
] |
[
"Why can we effectively store Hydrogen, but not Helium, without it escaping, when it is a smaller molecule?"
] | [
false
] | Helium cannot truly be contained in any present vessel, as it just evaporates out. Does hydrogen not share this property? | [
"Helium gas is contained just fine in a metal vessel. ",
" helium is usually stored in some sort of Dewar vessel at 4 K, which has to vent gas as it evaporates. This problem is common to all cryogenically-stored gases (liquid nitrogen, oxygen, hydrogen...) which will also have to periodically vent vapor to keep... | [
"Helium is a smaller atom than hydrogen (due to increased nuclear charge with no increase in the electron shielding effect) and hydrogen exists as H2, not just H. An H2 molecule is significantly larger than an He atom."
] | [
"Is it not true that hydrogen gas is H2, while helium is He is just He, so an H2 gas molecule is actually much larger than a He atom/molecule?"
] |
[
"Does social media and smart phone usage lead to more childhood memories being remembered?"
] | [
false
] | Recently I’ve been thinking about how, in my lifetime, the internet and advancement of smart phones has changed rapidly. I was born in 1993 so although I did grow up with social media and smart phones to an extent, it is in no way comparable to someone born after ~2005. People are now growing up during a time where sma... | [
"Good evidence will probably require more time, since the newest generation is still so young that they won’t have forgotten their childhoods anyway. ",
"Personally, I think it will probably remain dependent on each individuals capacity for memory. I was born in 83, which means my entire child and teenage years w... | [
"I almost think the opposite could be argued. Photo processing was a huge enterprise back in the day and going to walmart or other retailers to get photos developed was not at all an uncommon occurrence. Perhaps anecdotally, but every family I knew growing up, including my own had numerous books filled with old p... | [
"Taking photos actually worsens your memory for events. Here's the lay write-up.",
"https://qz.com/1295131/research-shows-taking-photos-decreases-the-ability-to-remember-lived-experience/"
] |
[
"How fast would one need to accelerate a container of air to make it bunch up to one side, creating a vacuum on the other?"
] | [
false
] | Back when railroads were new, alarmists feared that the speed of the carriages going as fast as 20mph would create a deathly situation for the passengers. This was obviously quite wrong. But how quick of an acceleration WOULD be needed to start heaving the air in a contained space over to one side of it? | [
"For something like a planet with an atmosphere, you can define what's called a ",
" which is the height at which the density is reduced to 36%. For planets, the simplest expression is h=kT/mg where m is the mass of the molecule, g is the gravitational field strength, k is Bolztmann's constant and T is the temper... | [
"It's nice to see a question that hasn't been asked a gazillion times."
] | [
"And just for additional info, the 36% comes from the fact that 1/e=0.3679..."
] |
[
"Why are dreams feel so long although they are rather short ?"
] | [
false
] | null | [
"I'm no scientist, but I would guess that it's because you're not fully conscious. The conscious mind shuts down, and so does some other parts it seems. This does not mean your brain is shut down, it is in fact running as fast as ever. It is constantly running, sorting through information, and sometimes initiating ... | [
"When REM sleep episodes were timed for their duration and subjects woken to make reports before major editing or forgetting could take place, it was determined that subjects accurately matched the length of time they judged the dream narrative to be ongoing to the length of REM sleep that preceded the awakening."
... | [
"I tried googling about dreams, but didn't want to use wiki as a source. I couldn't find anything that was an actual source, just a bunch of dumb sites.",
"Anyway, as I understand it, REM sleep is a stage just before waking up. It's possible that certain brain systems reactivate during that time. It seems the min... |
[
"Some questions about Feynman's double-slit experiment"
] | [
false
] | This probably makes no sense, but I have a couple questions. If all particles of matter take infinite paths traveling in every possible direction, wouldn't that mean some of them overlap, run into each other, or occupy the same space at the same time? Is this the cause of the interference in the experiment? Is this be... | [
"Feynman's? It was first done by Young around 1800.",
"Yeah, more or less. The interference patterns are caused by the wavefunctions overlapping each other.",
"The largest particles that have shown this type of interference, that I know of, are buckyballs, which are made of 60 carbon atoms.",
"But the double ... | [
"The only experiment Feynman is known for is trying to run water backwards into a sprinkler."
] | [
"The double-slit experiment was around long before Feynman, but he is primarily responsible for introducing that infinite paths idea you referred to. One of the simplest applications of his path integral formulation is in regards to the double-slit experiment. That's probably why you saw his name attached to it."... |
[
"Why do dogs obey our commands?"
] | [
false
] | Hopefully this hasn't been asked, I did look for it but we all know how effective the search feature is. Any way I was wondering what makes dogs so willing to submit to people and take commands so well (generally). | [
"It pretty much comes down to conditioning. A dog that has not been trained won't sit when you say 'sit'. You have to say 'sit', then push down on its behind so it will sit down, and then give it a treat. This way, the dog learns to associate 'sit' with sitting down and getting a treat. Eventually, you won't need t... | [
"We've selectively bred them to be good at it."
] | [
"I'd like to note real quick here, dogs learn better if you allow them to do the command themselves versus \"pushing\" on them to do it.",
"So for sit, you bring the treat slowly over their head until they are forced to sit in order to see it, then you reward them. They'll learn it a lot faster because they aren'... |
[
"Another telescope question--how big do they need to gather the light?"
] | [
false
] | I've been hearing a lot of people talk about using two telescopes to increase the effective size of the mirror, which affects the resolution the telescope can see. But another point to consider is the actual reception of photons. How big a mirror (or mirrors) would you need to have a reasonable exposure time for your... | [
"It depends on what you want to see, and how long you want to wait. In general, the larger the telescope area, the more photons you can pick up. And, the longer you wait, the more photons you can pick up as well. For example, the Hubble Deep Field images you might be familiar with took several 30-40 hour exposure... | [
"The nearest exoplanet discovered is ~10 light-years away. If we assume the planet is identical to earth, we can say that it receives ~1350 W/m",
" of light from its star, reflecting about 30% of it. This means that in full phase, the planet would emit 10",
" W of light. The amount of light that reaches earth... | [
"I'm sort of specifically thinking about exoplanets here. It occurs to me that for a planet a 40 hour exposure wouldn't cut it since the planet would rotate, blurring any view. This seems like a complication in observing them I don't hear discussed often, so I want to find out more."
] |
[
"Change laser frequency Possible ?"
] | [
false
] | I was reading about lasers how they pass prisma's etc. While reading. I wondered why is it not possible to change the color of laser ? When i think of a laser it's a frequency with an amplitude those two combined are its energy; so if frequency and amplitude can be changed the energy would stay the same here. But it i... | [
"It is, in fact, relatively easy to make a higher wavelength laser from a lower one. You take the energy from one photon, and use it to generate a photon of less energy. Many lasers actually work this way.",
"Getting a lower wavelength laser from a higher one is trickier, because you have to increase the photon... | [
"In addition to the nonlinear processes described by shadydentist, you can also shift the frequency of a light beam by passing it through an ",
"acousto-optic modulator",
"."
] | [
"You can. Read about ",
"DPSS",
" lasers."
] |
[
"Mold smells like dirt. So does dirt smell like dirt because of mold?"
] | [
false
] | At least some molds tend to smell like "dirt". But why? When we smell dirt are we actually smelling mold (or what's left of it)? | [
"When you smell dirt it isn't mold you're smelling but a bacteria called ",
". See below for an excerpt from the ",
"USDA on Soil Biology",
". ",
"Actinomycetes are a large group of bacteria that grow as hyphae like fungi (Figure 3). They are responsible for the characteristically “earthy” smell of freshly... | [
"Exactly what I was looking for! Thank you very much!"
] | [
"Can I put those in my beer to get a ",
" \"earthy\" smell instead of that fake \"earthy\" smell all hops claim to have, or will they eat the sugar/alcohol/yeast and mess things up?"
] |
[
"If bruises are from bleeding underneath the skin, where does all the blood go when it heals?"
] | [
false
] | null | [
"Part of the leaked blood will coagulate and help to form the clot / scab to stop the bleeding.",
"Macrophages will come and clean up any \"loose\" blood, or debris, or old scab material - they take it in, digest it, and spit the digested remains out into the blood stream where it's filtered out in the kidneys.",... | [
"Why do macrophages come along and clean things up? What are their motivations and dreams in their life?"
] | [
"Their motivation is an increasing chemogradient of various chemical factors including interleukons, cytokines, disrupted lipoproteins from cellular membranes, and other chemotaxic molecules. They quite literally will follow the strongest gradient to its origin and boom perfect marriage. Which actually works out we... |
[
"Can you concentrate viruses to the extent that they form a solid mass?"
] | [
false
] | It doesn't have to necessarily be feasible with today's technology but could you hypothetically have so many viruses condensed in one area that it forms like a mass similar to a block of cheese or whatnot? | [
"Sure you can! Oftentimes, purifying virions means taking an initial stock of the virus obtained from infected cells, and running the stock through a sucrose cushion via ultracentrifugation to remove anything not dense enough to pass through, which usually gives you a pellet containing virions and any cellular mate... | [
"Also, the structure of many viruses have been determined by x-ray crystallography, meaning that people have grown macroscopic crystals made out of virions.",
"For example, this crystal is made from the polio virus",
"This crystal of tobacco mosaic virus was grown by NASA in the MIR space station!"
] | [
"How do they crystalize viruses?"
] |
[
"Could I maintain the high coefficient of performance of heat pumps if I put them in series for large temperature differences?"
] | [
false
] | Heat pumps work most efficiently when the temp. gap is small. So if I want to heat my home in northern Greenland when its -50°C outside the coefficient of performance would probably sink to 1. Now If I used a first heat pump to heat my garage to -30°C and then another one to heat the polar bear cage to -10°C using the ... | [
"Would I be able to get a COP comparable to the COP of a single heat pump working a 20°C gradient?",
"No. Your efficiency will be worse than the original single heat pump with the large temperature difference.",
"Efficiency of a given heat pump is analyzed in terms of ",
"thermodynamic cycles",
". A useful ... | [
"Sure, each can individually have a higher efficiency, but the aggregate effect will be lower efficiency.",
"polar bear cage",
"this seems more important."
] | [
"Hmm not sure if I am getting this 100% so a follow up question.\nThe heat pump from garage to bear cage does not know it is in such a cycle, so I supose its efficiency is still high (lets assume 5 jules per joule invested). Therefore I assume all the efficiencies of the pumps ,if looked at independently, would be ... |
[
"How exactly does electronic image stabilization work? Is it using a gyroscope?"
] | [
false
] | null | [
"It can be done purely with software. Go fire up Windows Movie Maker and you'll see a function to stabilize video built in to it. It is based on recognizing patterns in frames, recognizing translation and rotation, then manually countering those by editing that frame. This is for post-recording though, I'm sure th... | [
"Unfortunately on mobile and cannot pull up some sources at the moment, hopefully someone can help by providing some content to show what I'm about to describe. There are a few videos on it from various camera manufacturers showcasing their technologies and YouTube videos of people who explain it well and in depth ... | [
"EIS is always post-production. On most phones it's just so fast that you don't notice it. Biggest problem about automatic EIS is that you'll loose field-of-view. "
] |
[
"Has anyone tried or thought about building a sonoluminescent device either at home or in a lab?"
] | [
false
] | If so, did it work? I'm looking for a neat project to do in my spare time and I've always wanted to try this. | [
"I did this as a summer project, and ",
"our report is online here",
" (starting at pdf page 248, printed page 243). See the \"Bravo apparatus\" section for how to make a homemade setup. The key is to use Piezoelectric Drive Transducers - we tried using mechanical drivers and didn't get anywhere.",
"This wa... | [
"Yea, I have a tone generator and an amplifier, I just wanted like a somewhat official procedure."
] | [
"Awesome, this is what I was looking for, and with references! ",
" It'll be a few weeks/months before I get to it, but I'll hit you up if I run into issues."
] |
[
"Is there any truth to the notion that a musical instrument made of wood (guitar, violin, piano, etc.) will sound better the more it is played, due to the vibrations at musical frequencies the wood is exposed to?"
] | [
false
] | edit: My question was not specific enough. What I'm trying to get at is this (paraphrased from ): Can exposure to low energy sound waves over long periods of time alter physical structures and organic materials -- specifically wood, and acoustically resonant structures made of wood? If yes, in what way do they change?... | [
"This is a hard subject to track down, doesn't seem to be well researched. ",
"Apparently one company even had a service to \"age\" guitars by exposing them to powerful vibrations. They changed their website so I had to track it down on archive.org:",
"https://web.archive.org/web/20130121121636/http://www.acous... | [
"Your reply missed the mark. ",
"OP is asking if the spectral content of an instrument's sound changes over time as a function of how long it's been played."
] | [
"Your reply missed the mark. ",
"OP is asking if the spectral content of an instrument's sound changes over time as a function of how long it's been played."
] |
[
"If I stood on Saturn and looked up would I see the rings?"
] | [
false
] | null | [
"Yes you would, at least if you were looking at the part that was in sunlight. The part that was shadowed by Saturn would just look like a dark starless patch in the night sky.",
"The rings are actually very very thin, so if you were directly under them they would just look like a thin line crossing the sky.",
... | [
"Look up the Schumacher-Levy comet that hit Jupiter some years ago. Basically it penetrates at high speed, building heat through friction. Once it gets deep enough the heat and pressure cause a rather severe detonation."
] | [
"obligatory pedantry: you can't really stand on Saturn's surface, since it's gaseous",
"What happens when a solid object hots the planet?"
] |
[
"If every human on Earth disappeared right now, how long would it take for Earth to weather itself into a completely natural landscape; void of any man-made objects and buildings?"
] | [
false
] | null | [
"Life After People",
" documentary"
] | [
"The World Without Us",
", about what would happen to an urban area if people vanished."
] | [
"Came here looking for a number without having to watch a documentary. Left disappointed. "
] |
[
"Planetary geology has no jobs?"
] | [
false
] | Well i am starting my first year in community college this fall. No real direction but I've always liked astronomy. Long story short I think I'm interested in physical features of the cosmos (planets). Does this mean I should take geology opposed to astronomy? I searched here and found . It basically alludes to lack of... | [
"most physics is a lot of mathematical analysis of long data tables. Sometimes we graph things and can see patterns in the data, but a lot of it is \"just spreadsheets\" as you say. Not quite that bad, I guess, but close.",
"And astronomy has the unfortunate luck that the ",
" measurement they can make is light... | [
"Thanks. I don't mean to say just charts in a negative way. I just wanted to know what to expect. So far from everyone replies including yours I will brush up as much as possible in math, get physics and geology. Sorry for the delay everyone. I understand you're all scientists here, and your time is valuable. The d... | [
"I'm currently a grad student in a planetary science department.",
"The typical path is to get a PhD in planetary science or a related field. Generally, I believe classes in planetary geology are rare unless the university has a separate planetary science department.",
"Undergrad: I'd recommend doing a bachelor... |
[
"ELI8 for Rain vs Bubbles please?"
] | [
false
] | My 8yo recently discovered that bubbles do not pop in the rain, even rain brought in by a tropical storm (honestly, I was surprised too, I thought the torrential downpour would pop them). I tried to look up the science behind it and couldn't find an explanation that I understood well enough to explain it on the 8yo's l... | [
"Bubbles are soap and water, and they are held together by surface tension and atmospheric pressure. ",
"I can only assume that when you introduce more water to the structure of the bubble, the tension is broken with more of what is creating said tension, which would likely allow the water droplet to move through... | [
"I reckon bubble size, and rain drop size might influence your findings."
] | [
"In our case we were blowing bubbles during a very hard rain from the tropical storm that hit SC yesterday. Big bubbles and small bubbles all survived in the rain for decent periods of time."
] |
[
"Is it possible to build immunity to specific allergies?"
] | [
false
] | For instance, if someone has a peanut allergy, would they be able to consume/inject ever increasing dosages of a peanut based product in order to build tolerance and no longer be allergic to peanuts? Starting from a small dosage of course. | [
"It's not building \"immunity\", it's building up a tolerance for an allergen. Allergies should be handled by a qualified doctor, never try to do it on your own. Allergic shock can result and sometimes death. "
] | [
"I have a vivid memory of that first trip to the allergist when I was ~10 years old and they pricked my forearms with something like 40 needles dipped in different allergen solutions. The next hour of waiting to check for reactions to the different allergens was torture because I was allergic to pretty much everyth... | [
"Yes",
". It's relatively common for people with certain sever allergies. Source, my allergist keeps telling me I should get them."
] |
[
"How does computer memory work when the computer is turned off?"
] | [
false
] | Do the currents keep on going somehow in the semiconductor chips? Is it somehow that the state is stored in a static manner? | [
"Also, the way RAM is used now has some weird/fascinating side effects:",
"cold boot attack",
"rowhammer attack",
"bitsquatting",
"article"
] | [
"For RAM, the data is stored as charge in extremely small capacitors. The charge slowly leaks out of the capacitors and into the substrate, hence it must be periodically read out and written back. When the computer is turned off, the data is lost after a few seconds when the charge leaks away.",
"For flash memory... | [
"What you describe is actually a particular type of RAM, called dynamic RAM (DRAM). There is also static RAM (SRAM) which doesn't need to be refreshed, because its cells are made from configurations of transistors rather than leaky capacitors. SRAM is faster than DRAM, but its cells are also larger and therefore mo... |
[
"Does quantum mechanics mean fusion happens at the center of large planets and brown drwaves, even if just sporadically?"
] | [
false
] | null | [
"Yes, a tiny amount."
] | [
"Thank you! Follow-up question, is fusion happening in measurably tiny amounts? And at what pressure and energy level do we go from \"enough fusion to measure\" to \"functionally no fusion\". "
] | [
"I don’t know how you could measure the amount of fusion happening in the center of the Earth, you’d probably have to ask an Earth scientist about that."
] |
[
"What is the possibility that our known universe (or galaxy) is just a particle of a much bigger universe or world?"
] | [
false
] | null | [
"I'm sorry... what are you claiming the evidence suggests? There is a big gap between \"the universe extends beyond the observable universe\" and \"our universe is one particle in a bigger universe made up of a whole bunch of universes, where galaxies are fundamental particles.\""
] | [
"I've never heard of any evidence that suggests this:",
"all of the matter in our universe could consist of universes like our own, with life like us, or with things we could never imagine.",
"or this",
"this idea that galaxies, solar systems, or universes are atoms or other elementary particles in larger uni... | [
"I think there is some confusion here.",
"iorgfeflkd responded to this part of your post:",
"Over the years, I've speculated that since most of matter is empty space, our universe, which is mostly empty space, might just be a tiny portion of matter in a much larger universe.",
"As he explained, the evidence p... |
[
"Would a plant die if you put it in a room, tended to it properly, but only shone green light on it?"
] | [
false
] | I'm thinking this because green things reflect green light and absorb others. So, would this mean it wouldn't absorb any light? | [
"No, you are using the wrong graph. The graph you posted is for absorption of chlorophyll suspended in a ",
" and has nothing to do with the action sprectra of a plant. You're forgetting about accessory pigments.",
"I've done six years worth of ",
"photomorphogenesis",
" (this is radish and one of 4 grow s... | [
". Most plants use two pigments to photosynthesize, Chlorophyll A and Chlorophyll B.",
"Chlorophyll A absorbs near-UV and near-IR light (absorption peaks at 665 nm and 465 nm). Chlorophyll B absorbs blue and red light (absorption peaks at 460 nm and 647 nm).",
"Here's a graph",
"Edit: Okay, so it won't die... | [
"stoicsmile's got the best answer thus far.",
"I just wanted to remind people that,",
"Things look green because they reflect green light (i.e. white light (a mixture of all \"colours\") goes in, most wavelengths are absorbed/transmit, green light reflects, and is incident on our eyes).",
"Things look white w... |
[
"What was the first ever physics equation?"
] | [
false
] | null | [
"I would have to say Newton's ",
"Principia Mathematica",
" had the first ever ",
"Although ",
" in physics have existed right since 6th or 7th century BCE Greece right up to the 16th Century AD, when Galileo made some remarkable discoveries, I do not think there were any equations for these concepts, until... | [
"As near as I can tell, you're asking one of two question: One question is \"Historically speaking, what is the oldest attempt at formalizing mathematically a physical law?\"",
"The other possible question you're asking is \"What are the fundamental equations, the fundamental rules that give rise to all of physic... | [
"Newtons Laws are generally considered the first, although work using math to predict natural phenomenon had happened before him. The reason his work is considered the first is that it laid out a complete framework for describing mechanical things in a universal way. It's simplicity could be expounded on and used... |
[
"What would be different if the speed of light were some lower number?"
] | [
false
] | Or, to put it another way, if the speed of light suddenly slowed down, would we be able to measure this? And if so, how? | [
"The \"speed of light\" isn't a physical constant. It's a consequence of the fact that we use different units for distance and duration. We have to have a conversion factor to go between them, and the number ",
" the \"speed of light,\" is that conversion factor.",
"You can change the definition of either your ... | [
"Previous discussions:",
"http://www.reddit.com/r/askscience/comments/gegwv/why_is_the_speed_of_light_299792458ms_would_the/",
"http://www.reddit.com/r/askscience/comments/fxn5h/what_decides_the_speed_of_light/",
"http://www.reddit.com/r/askscience/comments/fwd03/has_the_speed_of_light_always_been_constant/",... | [
"The value of ",
" is ",
" It can't change, because it's literally not possible to imagine it being anything else. It's like trying to imagine fitting something ",
" than five pounds of sugar in a five-pound sack of sugar. Five pounds equals five pounds; the ratio of pounds per pound is ",
" A pound is itse... |
[
"When digesting a carbonated beverage, does the added carbon dioxide absorb into the body?"
] | [
false
] | I'm sure most of the gas is burped out, but of what remains, how much is absorbed? Chemically, does this add or subtract anything noticable to the digestive process? | [
"Any that is not burped out will be absorbed, as gases can freely diffuse across cell membranes. The issue is that CO2 quantity in soda is fairly minimal. Another interesting compound in soda is phosphoric acid, which is one of the most acidic substances that we regularly eat (pka ~2.15).",
"As far as the amounts... | [
"Most are just ingredients. CO2 isn't the most reactive substance in the world. CO2 will convert into carbonic acid in the presence of water:",
"CO2 + H2O <------> H2CO3",
"But without an enzyme catalyst (the body uses Carbonic Anhydrase in many areas, especially the kidneys and lungs), the reaction is extremel... | [
"Thanks! This brings up another point/question if you wouldn't mind. Of the various acids in soda, which are ingredients and which are reactions from CO2?"
] |
[
"Regarding a comment in r/science about HAARP"
] | [
false
] | Above is a link to the top rated comment on a post about the atmosphere above Japan heating rapidly before the March 11 earthquake. I have heard one person on reddit go off about HAARP before, but the guy could barely formulate a sentence and could not explain why he thought was responsible for the earthquakes in Japan... | [
"I'm not an expert but I can give you the basic answer: The HAARP doesn't have any role in these things. It heats the ionosphere. That's about it. If you read the whole HAARP wiki article you'll see that popular fiction has contributed to the conspiracy theories. ",
"Your question isn't lame, but when faced with ... | [
"I work with high power RF systems, although not in the megawatt range. There is simply no physical mechanism by which a pulsed or continuous high-power signal can cause an earthquake, let alone an earthquake thousands of miles away. If you assume that the HAARP transmit antenna is omnidirectional and you're rece... | [
"HAARP will always be a subject to conspiracy theories because people don't understand the ionosphere, don't know what HAARP does and because it is in a remote location.",
"There is also ",
"some evidence",
" that earthquakes can have effects on the ionosphere. So they read \"Earthquake = Ionosphere\" and the... |
[
"Could you have a homonuclear diatom of phosphor or sulfur with 5 or 6 bonds between them respectively?"
] | [
false
] | I know that Disulfur exists, but based on the page I found, it is only bonded by a double bond. Since sulfur is able to have 6 bonds, could all those bonds be with another sulfur molecule? | [
"Alright it’s flared"
] | [
"Alright it’s flared"
] | [
"Molecular orbital theory is a better way of looking at it and a way of rationalizing disulfur on its own is a doubly bonded diradical (chemistry is rationalization after the fact). To keep it super short, you can assign electrons into bonding, anti-bonding, non-bonding orbitals, and symmetry determines which of th... |
[
"Are mosquitoes as deadly to other mammals as they are relatively to humans?"
] | [
false
] | null | [
"Hi ljvw33 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 followin... | [
"Planetary sci flair?"
] | [
"Sorry probably biology flair.."
] |
[
"How far are we from creating a real life, fully inmersive but non-invasive VR experience and what are the cons and limitations?"
] | [
false
] | null | [
"Such hypothetical / speculative / open-ended questions are better suited for our newish sistersub ",
"/r/asksciencediscussion",
". Please post there instead."
] | [
"Ok. Should i delete this one?"
] | [
"Already removed."
] |
[
"Are there organisms between animals and plants like there are organisms between humans and monkeys? If we know what came before humans and when humans and chimps diverged can we tell when animals and plants diverged?"
] | [
false
] | null | [
"I think you'd be disappointed with the organisms you're thinking about. They were certainly microscopic organisms of some sort, living in marine environments. They likely resembled",
" protists",
".",
"The ",
"last estimate I'm familiar with",
" for the plant-animal divergence was ~1.5 billion years ag... | [
"Check out ",
"this great 2010 review",
". What you're asking about is the last eukaryote common ancestor, known as LECA for short. LECA was the last common ancestor not just of plants and animals, but also of fungi and all the protists (unicellular eukaryotes like amoebas, diatoms and dozens of other fascinati... | [
"Question is worded a little strangely but the field taxonomy generally serves to parse out the difference between species and when they diverged. You can view phylogenetic trees (which bring a visual to relation via common ancestor) which are visual depiction of relation usually via common ancestor. Warning: there... |
[
"Spaceballs: What - if anything - would happen if I coated an actual radar dish with jam or jelly?"
] | [
false
] | null | [
"Nothing good. It would would probably mess with the frequency of both the transmission and reflection. I think if you got a picture on the screen, it would look really saturated. I think it would also cook the jam. Maybe even catch fire. ",
"This is not a scientific answer obv. I am a technician and approached w... | [
"The question didn't specify whether the radar dish is a transmitter or receiver. I can't answer either question because it's a broad question. But I would say transmitter or receiver would change parts of the answer.",
"Funny story. I was on top of a commercial building once and there was a new piece of equipmen... | [
"It wouldn't change the frequency of your signal, that's set by the driving electronics. Most likely it would just hurt your signal to noise ratio, probably not catastrophically. If you manage to short the antenna to the ground plane then you'll get essentially no signal and possibly could break the driving electro... |
[
"Is there any connection to volcanoes erupting and earthquakes?"
] | [
false
] | null | [
"Sort of, but not always. Earthquakes are usually the result of stresses built up in rocks due to the movement of the various segments of the surface of the planet, either directly where they contact or at a distance due to the pressure the movement creates. In some places, \nlike the rim of most of the Pacific Oce... | [
"As the other comments have indicated, there are associations in terms of the majority of earthquakes and volcanoes both being ultimately driven by plate tectonics (and thus we expect many of them to be colocated) and earthquakes associated with movement of magma linked to volcanic activity (i.e., ",
"harmonic tr... | [
"Volcanically-",
" long period ",
" are produced by vibrations generated by the movement of magma or other fluids within the ",
". Pressure within the system increases and the surrounding rock fails, creating small ",
"."
] |
[
"What part of the brain keeps you breathing without having to think about it?"
] | [
false
] | null | [
"The ",
"respiratory center",
" of the medulla oblongata (part of the brain stem) controls autonomic respiration. It regulates breathing rate and depth in response to relevant stimuli such as CO2 levels in the blood. The medulla oblongata also mediates control of other aspects of the ",
"autonomic nervous sys... | [
"Just to add on a little more detail, the Pre-Botzinger complex in the medulla is thought to be responsible for respiratory rhythm generation even when you're sleeping",
"http://en.wikipedia.org/wiki/Pre-Botzinger_complex"
] | [
"Additionally the Apneuistic centre in the Pons stimulates the nerves in Medula's Resp. Centre, setting the intensity of breathing. The other control group is the Pneumotaxic centre also found in the Pons which antagonizes the Apneustic ceneter reducing the frequency of inspiration, causing an increase in depth."
] |
[
"Why can I use a propane stove indoors, but not a propane grill?"
] | [
false
] | null | [
"There is nothing in principle preventing a propane grill (or propane anything, such as a camp stove) from being safely used indoors. However for a product designed for use outdoors, it would be an egregious and frivolous liability ",
" put a warning on the product. Why risk getting sued when someone burns their ... | [
"You can, but you shouldn't. As the propane gas is burned, it releases the heat that cooks your food, but also deadly carbon monoxide. A camp stove and a propane grill both produce this gas, but the grill will produce a higher volume faster. So, both could kill you, but the grill is more likely to kill you. "
] | [
"The (perhaps obvious) answer is that stoves -- especially non-electric ones -- are built with overhead vents. The reasons for those vents are multiple -- but one of them is for removal of CO from the work-space.",
"If you would have a sufficiently-sized HVAc unit collecting the gases emanated from the grill then... |
[
"Does forward trajectory/momentum decrease the vertical impact on a drop?"
] | [
false
] | [deleted] | [
"As my high schools physics teacher used to always say/do:",
"\"This...\"",
"*Waves arm up and down* ",
"\"has nothing to do with...\"",
"*waves arm side to side*",
"\"This!\""
] | [
"Correct. The board has no lift, so it can't be used to glide a rider to a soft landing. ",
"The vertical drop is the same between a 10' vertical drop or a drop over a flight of stairs that is ten feet high. The rider would have to employ \"shock\" abortion for both cases."
] | [
"Not really. It is about the same as them jumping off a platform of the same height as the stairs. They aren't travelling forward fast enough to get much lift from their board or their body. ",
"The flexible board takes some of the impact forces, and for the rest, they have bendy knees, ankles and hips. A rider w... |
[
"AskScience AMA Series: I'm Sam Greenspan, a reporter who talked to 10 medical experts who were horrified to learn that Florida is using their research to deny care to transgender kids. AMA!"
] | [
false
] | Last April, I was visiting family in Florida when a friend, who works in health care, showed me a memo that she received from the state Department of Health, offering scientific explanation for why gender-affirming care should be denied to children in the state. I started clicking the links in the memo, and reading wha... | [
"I am medical, and not anti-anything.",
"Is there solid evidence that the (potentially irreverisble) harm from the hormonal manipulation of developing children is outweighed by the harm created from them waiting until they are a legal adult?",
"A clinic offering such services here in the UK was recently shut do... | [
"What specifically did the studies say, and how specifically were they being misrepresented?"
] | [
"I spoke with ten authors across 8 of the 12 research papers that Florida cited in a memo sent to medical providers in the state. All of them told me the same thing: that Florida was misusing their writing to make them say something that they did not. ",
"For example, the memo cited one paper as saying “‘...hor... |
[
"How exactly do jellyfish work"
] | [
false
] | [deleted] | [
"The toxin on a jellyfish's tentacles contains a paralyzing agent (sort of like a bunch of tiny little grenades). The way this works is that, once the tentacles touch you, the \"grenades\" blow up. The \"explosions\" shoot the toxins into your skin. Depending on the size of the prey and the potency of the toxin, th... | [
"I'm pretty sure that jellyfish can detect chemicals in the water left by prey. A lot of organisms decide which direction to go based on chemotaxis, even bacteria. They have no higher thinking ability, so they just float around until they detect a signal and start moving toward or away from it. "
] | [
"The toxin acts independently - for comparison, a komodo dragon doesn't control the bacteria in its mouth, but whatever it chooses to bite still gets infected",
"As to how the jellyfish knows how/when to eat its prey, I couldn't tell you. I do know, however, that a jellyfish knows to eat when it realizes whatever... |
[
"Would single stage rockets be achievable on Mars?"
] | [
false
] | With its decreased gravity would single stage rockets that go from the Martian surface to Martian orbit or even interplanetary space be achievable with already existing technology? | [
"Design Reference Architecture",
" Edit: see below, they've considered single-stage and two stage ascent vehicles, and are planning for two stages.",
"As you said, because of Mars' low gravity single stage to orbit is not difficult.",
"Landing such a heavy craft on Mars is the hard part. It has more gravity t... | [
"By \"current technology\", do you mean vehicles we have actually built and sent to Mars or vehicles that we are capable of building? Surely something that \"hoverslams\" like the Falcon 9 could do better than the sky crane."
] | [
"Yes, the ascent vehicle in NASA's current ",
"Design Reference Architecture",
" is single stage.",
"That doesn't seem to be in the source you linked? I understand it's nominally a two-stage rocket:",
"Propellant quantity calculated were based on a ",
" of 40 t (wet mass) with a total ascent delta-V of 56... |
[
"Can I replace a 6V 5Ah battery with a 6V 12Ah Battery?"
] | [
false
] | [deleted] | [
"Amp-hours are a measure of battery capacity. The second one will just last longer between charges. Assuming there is no funny business about peak current they're interchangable. "
] | [
"Short answer: yes. Long answer: something puts a load on the battery of a certain number of watts - that's voltage times amperage. Voltage measures the potential energy of the charge, and amperage reflects the actual quantity of electrons with that charge are available. Your device is going to require a certain am... | [
"Math:\n1 A = 1 C/sec then\n1 A-h = 1 C/s * 60 sec/min * 60 min/h = 3600 C. C is Coulomb, the unit of charge. "
] |
[
"What amount of energy is released in a single hydrogen-antihydrogen annihilation event?"
] | [
false
] | How is that number arrived at? Is it just the rest mass of the pair converted into energy via E = mc ? I'm interested in knowing the exact value of the energy released when they collide at some speed . | [
"Actually yes, it is the rest mass energy + kinetic energy. This is a direct consequence of the conservation of energy. However, if it helps most of the mass of the particles is due to the strong force not even the rest mass of the quarks. In reality the two are bound together by energy which makes up their mass. "... | [
"Okay, but what's the actual value? If a hydrogen atom and antihydrogen atom collide at speed ",
"s",
" going directly towards each other, how much energy is released?"
] | [
"You need to know the masses of the final state particles in order to answer that.",
"Complete proton-antiproton annihilation is messy. There will be a whole bunch of random particles in the final state. You can't really predict it on a case-by-case basis.",
"https://en.wikipedia.org/wiki/Annihilation#Proton-an... |
[
"If the earliest humans looked a lot like apes, what did the earliest apes look like?"
] | [
false
] | Badgers? Deer? Mongooses? Mongeese!? | [
"Gibbons and apes share a common ancestor. So, probably, like a gibbon.",
"Before that, old world monkeys."
] | [
"Humans still are apes. Our more distant cousins include old world monkeys, then prosimians like lemurs, then tree shrews, then rodents. Our ancestors were smallish furry things, the earliest known primate-like mammal is ",
"Plesiadapis",
" and an early ape-like genus was the ",
"proconsul"
] | [
"Exactly what I was looking for, thank you!"
] |
[
"Have antacids ever been investigated for increasing the absorption rate of medications?"
] | [
false
] | Like may people in the world, I've been on medications which require waiting before and after eating. ( a good example of this being Synthroid, the thyroid medication) The main reason doctors give for waiting to take medication - before or after eating- is the food ingested causes acid flow which then eats away at the... | [
"Absolutely! But I think you are also asking about ion trapping.\nStomach acid clearly alters Biotin absorption, so the answer to your question is an easy YES.",
"\nFor many drugs, however, the effects of pH are more complicated than just stomach pH.\nThe central issue with pH is whether a drug molecule is ioniz... | [
"Related question, if you don't mind. :)",
"My small and large intestines were both shortened as a result of surgery for serious Crohn's Disease complications. Since then, it seems that generally, medicine doesn't last as long, or work as well. ",
"For example, my pain medicine usually only works for about half... | [
"A big reason the antacids and foods mess with absorption is not usually the pH. Most common antacids contain large amounts of calcium, which depending on the medication can combine with it and make an insoluble salt that can no longer be absorbed. Antacids taken with a meal will also decrease phosphate absorbed fr... |
[
"Do smartphones have a quartz timekeeper in them like a wristwatch, or do they measure time some other way?"
] | [
false
] | [deleted] | [
"There probably is a quartz crystal for keeping the processor in check, but the actual time it shows on your screen is downloaded from the cellular network. They do this because having the accurate time is part of network handshaking (connecting calls, dats transferring, etc) and for billing you based on usage. M... | [
"Phones and computers typically connect to ",
"time servers",
" to make sure they have the right time. Computers and phones also have an internal clock with a battery to keep it running when powered off; these are usually resynced with the time server when you connect to the Internet. This internal clock is fai... | [
"Phones have several quartz crystals for the processors, radio synthesizers, etc.. These usually run at 10-20 MHz and the frequency is converted up/down for various uses. They might also have a dedicated watch-type quartz crystal running at 32kHz. Those crystals are a different cut and are more accurate, which is w... |
[
"Is there a large difference between the air pressure inside the tallest floor of a skyscraper and the the air outside?"
] | [
false
] | I work in a 40 story building, and yesterday while staring out the window I wondered what would happen if the window shattered in a much taller building (i.e. the Burj Khalifa in Dubai). Would the air inside the rush out or would air rush in? Is there a great difference in air pressure on both sides of the glass? To na... | [
"Hello! Civil engineer here. What you're asking about is pretty well related to something called the ",
"stack effect",
", which is a difference in air pressure relative to elevation from the ground contributing to air movement between lower and higher floors. In summary, due to leakage in the building envelope... | [
"HVAC Professional here. The direct answer to your question is \"it depends\". ",
"Modern HVAC systems are designed to maintain a slightly positive pressure inside the building during summer, and neutral or slightly negative in winter. In the summer, the hot outside air is more moist than dryer, conditioned co... | [
"Scuba Instructor here - You cant get decompression sickness from being raised in an elevator for the following reasons;\n1) Even in the tallest buildings, there is not enough of a pressure differential among the thousand feet or so of maximum altitude.\n2) Think about flying in an unpressurized aircraft, like the ... |
[
"Why are people able to distinguish color more precisely than musical tones? Is it possible to train yourself to have perfect pitch?"
] | [
false
] | Unless a person is colorblind, it's easy to distinguish colors: red is different from green is different from dark green is different from grey-green, and those differences are immediately apparent, near-universal, and nearly indisputable. With sound, though, it doesn't seem to work that way. People can distinguish dif... | [
"Play two tones, you will hear the difference. See two colors, you will see the difference. Perfect color vision (tell me the wavelength of the color you see in front of you) is probably more rare than perfect pitch (in its simplest form tell me what this frequency is). "
] | [
"I think perfect pitch is more about the ability to name notes with no previous reference. Example, if someone showed you the colour red and you had seen no colours previous to it in that scenario, you would still know it's red. You don't need to see blue and then red to be able to say it's red. I don't think namin... | [
"Colors and notes are both spectrums that are divided into quanta in culturally-determined ways. Learning these categories is a function of exposure and training to the exemplars. Most of us receive training as children for colors, but not notes. Neuroscience: we know from single-neuron recordings that training in ... |
[
"What is the molecular structure of a diamond?"
] | [
false
] | null | [
"Thanks for that (I kind of guessed that otherwise we would be overruled with an infinite supply of diamonds!) but how does it end? ",
"If the structure is as my teacher described how does an edge exist, is it just as basic as a carbon molecule missing from the diagram or is there something more to it? "
] | [
"It forms a lattice -- you can find a picture on Wikipedia or on Google images"
] | [
"It's not infinite. It ends. "
] |
[
"Why are the electrons of an atom not repelled by its neighboring element's electrons when forming a compound?"
] | [
false
] | From my understanding when a compound is formed it is through the attraction of one elements electrons to the neighboring elements protons. Why then are the electrons of the element not repelled by the negative charge of the neighboring element's electrons? | [
"In terms of classical physics/electromagnetism (including classical electrostatics, with Poisson's equation etc) you cannot explain the existence of atoms, much less compounds. Electrons behave quantum-mechanically, so quantum mechanics is required to properly describe this.",
"The main force (if you can call it... | [
"then how does the compound form. Obviously my asking the question is proof enough that I don't know much about this. \"They are\" is not exactly an answer that is very fulfilling."
] | [
"Short answer a.k.a. high school chem level answer, because by sharing, both atoms have 8 valence electrons and atoms \"like\" that.",
"Moderate answer or undergraduate level answer without the math (this one may go over your head depending on how much coursework you have under your belt). Molecules have orbitals... |
[
"How much thrust is needed to accelerate spacecraft by 1g in space ?"
] | [
false
] | I was reading wiki artcile on RF thrusters in the article it states that scientists were are able to produce 720 mN with 2500w of input power. What is an example load/acceleration that can be achieved by this thrust in space far from earth? | [
"Those things (EM drive, etc) are a scam.",
"By the way, the thrust is acceleration * mass. So 1g * mass of the rocket in kg = thrust in Newtons."
] | [
"Those things (EM drive, etc) are a scam.",
"Just curious, has this been definitely proven? Or we just know because Newton?"
] | [
"1) because Newton, and the entirety of modern and contemporary physics",
"2) theory is quantum woo",
"3) there is no peer-reviewed data after years",
"Number 3) is the most serious."
] |
[
"How did we determine the contents within a Neutron Star?"
] | [
false
] | Upon watching a video about , I wonder how we are able to calculate the contents within the Neutron Star without being near one. I presume we're using waves of the sort, but how is our current method of determining a Neutron Star's contents done and how is it considered reliable? | [
"Neutron star interiors have not been directly measured. Instead, we use a combination of a less direct but no less valid means to ascertain their interior structure and composition. ",
"The general structure of neutron stars is understood through a combination of stellar structure physics and the properties of t... | [
"Great answer. One additional component I wanted to add for others is how we observe the arrival times of pulses, which act as a really standard clock. As the pulsar spins, it emits beams of radiation and like a ",
"lighthouse",
", we see these as pulses. The precision with which we can estimate the arrival tim... | [
"These models are quite sophisticated, and predict a number of interesting behaviors, including superconducting regions and superfluidity in their cores.",
"I can't not add ",
"nuclear pasta",
" to this list!"
] |
[
"Does drinking water alleviate allergies?"
] | [
false
] | null | [
"Yea, I kinda meant more water than you would ordinarily drink. Didn't think I'd have to clarify that."
] | [
"That isn't a bad hypothesis because you are thinking about flushing histamine out, but unfortunately the histamine is chilling outside of the digestive tract. Water never hurts, but it probably won't make a big impact. "
] | [
"Just a reminder there is a guideline of how to post questions to askscience. If you ask a vague question with little context you're likely to get a vague response with little context. ",
"If you decide to post a question: Make sure your question is complete, clear, and precise. Avoid acronyms. Avoid using vague ... |
[
"AskScience AMA Series: I am Seth Shostak, senior astronomer at the SETI institute. Ask Me Anything!"
] | [
false
] | I'm , Senior Astronomer at the , and I've bet anyone a cup of coffee that we'll find convincing proof that the aliens are out there within two decades. I'm involved in the modern search for intelligent life in the cosmos. I have degrees in physics and astronomy, and has written four books and enough articles to impress... | [
"Let's say SETI discovers Alien life of any kind. Is your organization obligated to share this information with the US Government or Military first? Do they get to decide when/ how much the public gets to know or does SETI get to share what they find with the world directly?"
] | [
"That's the beauty of all conspiracy theories! Nothing I (or anyone else) says will dissuade those who believe in the conspiracy! But we're not under obligation to tell the gov't or military first, second or ever. In real life (as opposed to movies), whenever we get an interesting signal, the newspapers, radio a... | [
"That's the beauty of all conspiracy theories! Nothing I (or anyone else) says will dissuade those who believe in the conspiracy! But we're not under obligation to tell the gov't or military first, second or ever. In real life (as opposed to movies), whenever we get an interesting signal, the newspapers, radio a... |
[
"What’s actually happening when power goes out and comes back on after a few seconds during a storm?"
] | [
false
] | null | [
"The most common occurrence would be a branch falling on a power line and creating a temporary fault. This fault will cause a high level current to run through the circuit which if left unattended could damage transformers and the conductors themselves. For this reason protective relays are placed in the circuit. R... | [
"Just for completeness, the devices that do this are known as \"reclosers\"."
] | [
"...and reclosers are often programmed to retry two or three times before leaving the circuit open....which is why the lights might come back briefly before losing power for good."
] |
[
"Is a black holes gravity so strong, that it even collapses atoms?"
] | [
false
] | [deleted] | [
"A black hole's gravity is ",
" strong the closer you get to its center, and at some point it would certainly be strong enough to overcome the nuclear forces holding atoms and even protons and neutrons together.",
"But because \"arbitrarily strong\" isn't a concept which makes physical sense (it spits out infin... | [
"Yes - this has already happened by the time a neutron star forms. White dwarfs are held up against gravity by electron degeneracy pressure, but if they're too heavy then this is overcome and the nuclei capture the electrons to form a mass of neutrons."
] | [
"Is the gravity so strong that even electrons flying around atoms collapse into a/the nucleus?",
"Yes, that already happens with neutron stars, the precursors of black holes. Quark stars, a stage between neutron stars and black holes, are also hypothesized, where the nuclei collapse. In a black hole everything co... |
[
"What is the difference of de Broglie's wavelength as opposed to the regular formula?"
] | [
false
] | So I get that de Broglie came up with the idea of λ = h/p One thing I can't get into my mind is how does this differ from the regular formula λ = v/f? Obviously the formulas differ since the first one relates momentum and the wavelength. But if I had a ball, and were asked to measure the wavelength (which it does have... | [
"Because these equations relate different quantities, they can't be seen as equivalent - so comparing them isn't necessarily straightforward. ",
"Let's first look at your test case of a photon. So, your known quantity is a wavelength. From this, the de Broglie relation gives you the ability to work out its moment... | [
"I think it's worth adding that the discussion of phase and group velocity is not just a problem for matter waves, but anything that isn't a plane wave including for light",
"I don't think it's the problem you bring up is fundamentally about matter waves, but more about wave packets. and the fact that they do not... | [
"Absolutely! I thought my answer was getting long enough already - but this is really important to understand when we move beyond the simple examples of individual massive objects or individual photons in a vacuum."
] |
[
"Just how big would, say, a 1000 year old lobster be?"
] | [
false
] | null | [
"I'm sorry, is this source a ",
" on ",
" !?"
] | [
"I'm sorry, is this source a ",
" on ",
" !?"
] | [
"http://books.google.com/books?id=mtUO-Hi3iIMC&pg=PA169&lpg=PA169&dq=6+foot+lobsters&source=bl&ots=rtVsG8ASkt&sig=BCMg6t-HpkbAaZ0emlNorP1v1n0&hl=en&sa=X&ei=N2ueUcfMLcOGjAL1h4HABw&ved=0CF0Q6AEwBw#v=onepage&q=6%20foot%20lobsters&f=false",
"third paragraph",
"Also lobsters grow about 1lb every 7 to 10 years, so a ... |
[
"Is it possible to slow down radioactive decay through cooling?"
] | [
false
] | Would it be possible to cool an element to where it will slow down the radioactive decay. | [
"To the best knowledge we have at present, radioactive decay is not perceptibly affected by any external conditions such as temperature or pressure.",
"Chemical composition of the substance slightly affects some forms (electron capture, internal conversion) of radioactive decay for some substances, but this is re... | [
"If you are dealing with room temperature to colder temperatures, no. But as an extreme example, if you heat Re-187 up enough to fully ionize it, it's half life will go from 42 x 10",
" years down to 33 years. The reason this happens is that Re-187 undergoes beta decay, but the mass difference between Re-187 an... | [
"This is why radiocarbon dating works. If the radioactive decay was affected by temperatures/pressure then carbon dating wouldn't work, as it relies on the radioactive isotope (",
" C) decaying at a constant rate in order to calculate the time/year of death of a lifeform. "
] |
[
"If Hawking Radiation is caused by the absorption of one side of a pair of virtual particles, how does this lead to a loss of mass/energy?"
] | [
false
] | Unless my understanding of virtual particle theory is completely incorrect (and I have no formal training, so it most likely is), isn't it essentially the creation of matter/antimatter pairs based on the premise that energy and mass are equivalent? My conceptual view of this phenomenon is based on the assumption that t... | [
"You're forgetting the gravitational potential energy of the particles, which is negative. In particular, for a particle at the horizon the potential energy is -mc",
" and so the total energy is mc",
" - mc",
" = 0. If you were to create a pair, one inside and one outside, the one inside would have potential ... | [
"I'm simplifying a lot here, but essentially consider the geodesic eqt in Schwarzschild coordinates (c=1):",
"(dr/dτ)",
" = (E/m)",
" - (1-",
"r/r_s",
")(1 + (h/r)",
")",
"where E is the energy and h is the specific ang momentum. Consider dr/dτ = h = 0 for a moment.",
"(E/m)",
" = 1 - ",
"r/r_s"... | [
"No, because gravitational potential energy is always delocalized in a sense and cannot be used for these nefarious intents. For Alcubierre and other pathological phenomena you need \"genuine\" negative energy density, not counting gravitational potential energy."
] |
[
"Is it possible to create a better numeral system?"
] | [
false
] | The one we use right now is , but this and the decimal point and etc. were invented in the past, when we didn't yet know many things about the world that we know nowadays. [Because I mean pi doesn't have anything to do with 3 and a bit more of some items, does it?] | [
"I dunno. I like decimal. Let me make my argument for it:",
"First, we can express all of our numbers as a sum of a_n*b",
" where a_n is the digit, and b is the base we're working in; and we need b amount of a_n symbols to express values from 0 to b-1. I'm not sure of a more efficient way to express numbers out... | [
"Arithmetic isn't really what makes most things hard. When you're working out a problem, it's pretty common to just have letters in place of all the constants that you assume, and constants that arise during a calculation can usually be expressed concisely with the integers we know and love, plus a small number of ... | [
"What about other, non-integer bases, like base e?",
"Then life gets really exciting! \"",
"Even more unexpectedly, the representation of a given integer in an irrational base may be nonunique",
".\""
] |
[
"What would happen if every toilet in New York City was flushed at the same time?"
] | [
false
] | null | [
"New York City is a big city, but the most concentration of residents is in Manhattan where very many people live in large apartment buildings with privately operated wooden (can you believe it?) water tanks on the roof, even in newer buildings. So the effect might not be as pronounced as in other places where toil... | [
"Took me a while to find it again, but this article on Wikipedia refers to spikes in resource usage based on collective behavior in cities:",
"http://en.wikipedia.org/wiki/TV_pickup"
] | [
"I though that they were an old system that was still there, not still in use. "
] |
[
"Given that there are many different systems of measurement for distance/size (e.g. meter v. inch or km v. mile), are there different measures of time as well? It seems like everyone uses seconds, minutes, hours..."
] | [
false
] | Perhaps this is a profoundly stupid question, but somehow this still rankles my mind. Why does the measurement of time seem standard, while there are many "non-standard" measurements of distance and size? | [
"Plenty of different measures of time and calendar systems. Its just modern society mostly agrees upon one standard base unit; the second though it didn't start that way; e.g., the Chinese used to have the ke, roughly 1/100th of a day. ",
"First note that length of a day and year are particularly natural ones d... | [
"I want a watch that displays unix time. People ask me what time it is and I respond, \"It's 371 past 1,355,260,000.\""
] | [
"towards the whole time system used on this planet.",
"(only going into the backstory of the most commonly used system cause otherwise we'd be here all year):",
"start point: ",
"753 BC -> Roman Calendar : 10 month (actually had a decimal system) summed up to 304 days a year. this obviously won't work well fo... |
[
"What is the deepest that we've dug into other planets/moons?"
] | [
false
] | null | [
"We've literally only scratched the surfaces of the planets and moons we've landed on (Venus, the Moon, Mars, and Titan), digging not much more than a meter (if that). There was, however, a mission which ",
"slammed a mass into the comet 9P/Tempel",
" in order to study its internal composition. The impactor was... | [
"Several landers have landed on the surface of Venus. ",
"Venera 4",
" sent measurements back from the surface in 1967. Of course, between the crushing pressure, blistering heat, and acid rain, nothing we send survives longer than an hour or so on the surface of Venus, but we've gotten numerous probes there all... | [
"isn't there a \"Wall\" in the atmosphere of Venus that, until fairly recently, we haven't made it past? ",
"I suppose i could do the research myself, but then what reason would i have to be on reddit??"
] |
[
"Why does superfluidity occur near absolute zero?"
] | [
false
] | I was reading the Wikipedia articles on and (because why not?), and I'm confused. My basic understanding of states of matter tells me that particles expand when matter is heated (turning a solid to a liquid) and contract when matter is cooled (turning a liquid to solid). So why does superfluidity occur near absolute ze... | [
"Superfluidity (similar to Bose-Einstein Condensation) occurs when particles size and particle separation are about the same, such that you can no longer talk about individual particles anymore. The temperature must be low enough such that the ",
"thermal deBroglie wavelength",
" (particle size) is approximatel... | [
"The important thing is that the average distance that a particle travels due to thermal energy gets smaller as the material cools.But the de Broglie wavelengths get longer as the material cools. It becomes a superfluid when the deBroglie wavelength becomes larger than the thermal spacing."
] | [
"Didn't I say exactly that?"
] |
[
"Does fluoride accumulate in the pineal gland?"
] | [
false
] | [deleted] | [
"Just a comment on impact factor. Low impact factor doesn't necessarily mean a journal is bad. Sometimes it just means the field is small - not many researchers publishing new papers, so there may be relatively few citations no matter how excellent the cited works may be. ",
"This is particularly the case for wil... | [
"I'll try to help out.",
"Caries Research is a low impact factor journal, with a very low number of 2.926",
". As a comparison, ",
"Nature has an impact factor of the 30's",
", depending on the specific journal. ",
"Impact factor",
" is a useful tool for understanding the quality of a publication, becau... | [
"Challenging the journal is valid, but this was a dissertation, and as such publication in a high impact journal is unlikely.",
"To further address your question, you need to ask 2 questions - whether the research was well performed, and whether it means anything.",
"Well performed: \n11 cadavers (small sample)... |
[
"How is it that menstruation is the best way to handle a woman's reproductive system? Evolutionarily, why is menstruation effective?"
] | [
false
] | null | [
"Most female mammals do not menstruate; most have ",
"estrous cycles",
" in which the endometrium is reabsorbed, rather than being expelled. So eliminating the uterine lining is not the only option available, and so one is led back to OP's question."
] | [
"I think it is important to realize that evolution doesn't create perfection or the best of anything. I think people sometimes fall into the trap of thinking of evolution as something that has a plan and it really doesn't. As F. Jacob said evolution is a tinkerer not an engineer. Where an engineer has novel parts... | [
"Reminder: Never, ",
" downvote an honest question. Honest questions are opportunities to learn, and downvotes are opportunities to suppress learning. How is that right in a science-based sub?",
"Kaas_, your question was clearly an opportunity for learning. Why it was downvoted I do not know/give two shits, but... |
[
"Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! ... | [
"Mercury, the now-smallest planet, is still an order of magnitude more massive than Pluto, so it's hard to imagine it having planet status revoked based on size. The remaining planets also have much more \"regular\" (circular) orbits which don't cross each other, and they aren't mixed up with other groups of object... | [
"Here's an excellent article: ",
"https://everydayastronaut.com/rocket-pollution/",
"While it points out some serious potential issues for a future world where rockets are a major means of transportation,",
"If we are worried about pollution or CO2 emissions, we have a lot bigger fish to fry. Rockets do not e... | [
"Here's an excellent article: ",
"https://everydayastronaut.com/rocket-pollution/",
"While it points out some serious potential issues for a future world where rockets are a major means of transportation,",
"If we are worried about pollution or CO2 emissions, we have a lot bigger fish to fry. Rockets do not e... |
[
"Why do objects fall at the same speed regardless of their differing masses?"
] | [
false
] | Asking on behalf of my GF, though I'm probably more stumped than she is. We understand it has something to do with inertial mass and gravitational mass being equal (the equivalency principle) but neither of us are very mathematically inclined and can't quite grasp it. I knew Newton got close on this and Einstein appare... | [
"F=GMm/r",
" . You can think of this as G being the gravitational constant, something to scale the force and mass and distance measurements, M as the mass of the \"source\" of gravity, m as the mass of the thing \"falling\", and r as the distance between their centers. Now you also know that F=ma, so ma=GMm/r",
... | [
"Both objects will accelerate at the same speed. This is because the force scales with mass, and acceleration=force/mass. So if you double the mass, you also double the force of gravity, and the acceleration stays the same."
] | [
"I suppose I understand that conceptually, but the why is missing. I guess my question comes down to why is that? "
] |
[
"Can/Does sexual abuse during a person's childhood affect their sexuality in adulthood?"
] | [
false
] | null | [
"Not in an actual biological sense ( ie. Born heterosexual or homosexual you will stay that way) but it can cause people to fear or have trust issues with the gender of the person who hurt them, therefor they may choose to be a different orientation. So no they won't actually change, but they can choose to not act ... | [
"That's a good question, I honestly don't quite know how to answer it. Because I could see how something like that could happen, but on the same accord I know of people who knew they were gay at a young age, but we're molested at an older age and still kept their orientation. (Knew they were gay at 4, molested at 9... | [
"Interesting!",
"Can childhood trauma in general affect the way children develop physically?",
"I have no idea what I'm talking about, but if a child constantly has reasons to be scared or depressed during major development stages of his or her childhood, can the hormones that cause fear/depression/etc. change ... |
[
"Why don't particles accelerated in a vacuum (therefore, no resistance) accelerate to infinity? (Or, more specifically, faster than light?)"
] | [
false
] | I've heard something about objects that approach the speed of light slowing down time relative to itself... But I've never really understood how. And it just left me with more questions. For example, why does light have a maximum speed? And what specifically propels light to begin with? I came up with these questions ... | [
"For the umpteenth time, mass does not increase with speed."
] | [
"For the umpteenth time, mass does not increase with speed."
] | [
"Nothing actually ",
" the rocket from accelerating until the end of time. The actual answer actually comes from how space and time is related, and how the speed of light comes in play between the two.",
"For starters, ",
"take a look at this comment",
".",
"As for your questions:",
"... why does light ... |
[
"Are humans, and women in particular, born with holes in our nipples or do they develop later in life (either puberty or during pregnancy/lactation)?"
] | [
false
] | Actually, this goes for all mammals. Do we know? It's a random and odd question, but I've been wondering for years and I haven't been able to find any concrete answers. Thanks! | [
"Do we know? It's a random and odd question, but I've been wondering for years and I haven't been able to find any concrete answers. ",
"The holes are always there. ",
"Many newborns lactate a little, even boys because they get exposed to hormones from the mother in the womb.",
"The nipples are just repurpose... | [
"How similar to sweat glands are they? Is milk just slightly modified sweat? Did lactation evolve from sweating? Some mammals don't sweat, is that a newer evolved trait? Holy shit this blew my mind!"
] | [
"Just for clarity, see the image on this webpage about breastfeeding: ",
"http://www.transitiontoparenthood.com/ttp/parented/ap.htm",
"As you can see, the milk ducts all lead to the nipple. It is very much like sweat glands and there is no single \"hole\"."
] |
[
"Can an axon glue together with a dendrite without any gap between them? What prevents them from gluing in a normal behaviour?"
] | [
false
] | Yesterday a psychiatrist told me that I might need an electrical brain stimulation because some of my dendrites and axons were glued together and electricity would unglue them. Is that true? How can electricity unglue them? | [
"This is Russia. She said there were some glued neurons in my brain. And then directed me to some medical center. I need to run through ",
"this test",
" and then to run through(I remembered) ",
"transcarnial electrostimulation",
" to unglue neurons there. And since I like biology a lot I'm trying to find o... | [
"Haha thanks! That explains the meldonium. The tests are common psychiatric tools. The stimulation is probably either transcranial direct current stimulation (tdcs) or transcranial magnetic stimulation (tms), interesting! ",
"I really think your psychiatrist is using easy or laymen terms or maybe we have a langu... | [
"Yes, probably she thought of synaptic depression. Anyway I'm currently reading ",
"about a synaptic cleft",
" - it is filled with molecular structures. So it can't collapse obviously. By the way, about a specific medicine I find interesting - along with meldonium and tdcs she prescribed me intramuscular inject... |
[
"What is the smallest physically possible colour difference?"
] | [
false
] | null | [
"The uncertainty in position times the uncertainty in momentum is at least the reduced Planck constant over two. If the photon is spread out through the whole universe, this works out to about 5.4*10",
" Hz. For comparison, the visible spectrum spans about 4*10",
" Hz, so there's room for about 10",
" differe... | [
"In reality, there is none. The spectrum of light is continuous, so infinitely divisible.",
"In computer images, the smallest color difference is directly related to how many bits are used to store color data."
] | [
"10",
" monochromatic colors.",
"But human color perception is 3-dimensional. ",
"On the other hand, human perception might have limits of perceptible differences between colors that are greater than the Heisenberg limit you calculated from."
] |
[
"Are thermonuclear supernovas really good enough standard candles to substantiate dark energy?"
] | [
false
] | Given the findings that white dwarf mergers may make up a larger portion of Type IA supernovae than originally realized how does this impact the data used as evidence for dark energy? IIRC the reason that Type IA supernovae were thought to be standard candles was that they were all thought to explode at the Chandrasekh... | [
"Supernovae Ia aren't quite standard candles. They're (as noted elsewhere) more like standardisable candles. They don't all have the same brightness, but there does appear to be a tight correlation between how bright their peak brightness is and how long they take to decay in brightness. So they can be standardi... | [
"People start calling them \"standardizable candles\". Our understanding of them is not perfect, but already pretty good, and with a very high probability good enough. They are completely consistent with independent measurements of the CMB and gravitational lensing."
] | [
"Same article for free: ",
"http://arxiv.org/abs/1105.0419"
] |
[
"Calculating wavelengths emitted by hot steel?"
] | [
false
] | Does anyone know if there equations for the relationship between the temperature of a block of steel and the wavelength of light emitted? (Not just idealized situations but for a real world application) Also, does the color change much depending on the alloy? | [
"Are you looking for something more specific than the ",
"black body equation",
"?"
] | [
"Fancy meeting you here! Black body radiation doesn't depend on the material, so different alloys will show you the same colour at the same temperature.",
"...except, reflected ambient light can interfere. Suppose you were using a spectrometer to take a temp reading, you'd fist calibrate it against a light sour... | [
"Tricky! I've thought about that, too, maybe in the form of an etched & smoked glass rod packed full of LEDs (I think getting the reflectivity close is important, and probably as difficult). I think what we need is data on human perception of continuous spectra. I'm a bit busy right now, but I will try to look i... |
[
"Is there an equation for the angle between N uniformly spaced vectors in M dimensions?"
] | [
false
] | Is there an equation to calculate the angle between N uniformly spaced vectors in M dimensions? More simply, is there a way to do it for only 3D. Example I have 13 vectors originating from the origin, what is the angle between any two of them? The problem is simple in 2D, ex. theta = 360/N. I was playing around with th... | [
"The first thing you need to sort out is what you mean by uniformly spaced. Instead of vectors we can think of N points on an (M-1)-sphere. So for M=2, a 1-sphere is just a circle, and we want to uniformly distribute N points. This is easy because we can just place them all at 360/N degrees apart.",
"Once you ste... | [
"It turns out there is no analytic way to do this mathematically for a general number of points even in three dimensions. I know this problem from my work as it pertains to so-called powder averaging of NMR interactions. The basic principle is the same: you are trying to distribute a number of points homogeneously ... | [
"It turns out there is no analytic way to do this mathematically for a general number of points even in three dimensions.",
"No known way or is there a proof?"
] |
[
"Could you inflate a balloon with ions?"
] | [
false
] | Why or why not? What would happen? Assume that we're using Chloride ions and a normal party balloon. | [
"Well, I just did a simple calculation; a mol of any gas molecules will give you about 11 liters of volume; so, if you're inflating a regular balloon, we'll say that's about .1 mol of ions (6.02",
"10",
" Coulombs, to find that the balloon will have 9632 C of charge. This is a lot of charge.",
"The ionization... | [
"I'm pretty confident that your reasoning is flawed. Ions of any kind would not have the same molar density as an ideal gas as they repel each other quite strongly. Ideal gases are only allowed to interact as hard spheres, but modeling a single ion species as hard spheres is unrealistic due to the long-range Coulom... | [
"Filling a ~10 L ballon with Cl- ions would create a charge of 43000 coulombs. Any electrically charged object would be very very attracted to this unimaginably large charge compared to everyday objects.",
"If you separate one coulomb of positive and one couloumb of negative charges, and placed the a meter apart ... |
[
"Hey Reddit, when you yawn, why does your hearing fade out?"
] | [
false
] | [deleted] | [
"I can think of three possible reasons.",
"\nFirst, there are somatosensory inputs from around the ear that suppress sound reception, and yawning will activate them (search for some work by Manis or Young and the word pinna). ",
"http://www.jneurosci.org/content/21/19/7848.short",
" ",
"Second, the middl... | [
"To clarify, should this cause a lack of hearing or \"white noise\"? I find that when I yawn it causes a dull ringing/whirring/white noise type thing covers up my hearing. It's kinda like occasional tinnitus..."
] | [
"To clarify, should this cause a lack of hearing or \"white noise\"? I find that when I yawn it causes a dull ringing/whirring/white noise type thing covers up my hearing. It's kinda like occasional tinnitus..."
] |
[
"If you scaled an ant to 1000x its size, would its legs still be able to support its weight?"
] | [
false
] | null | [
"Surface Area (in this case, the cross section of the legs) scales with x",
" but volume (and thus mass) scales with x",
" So if you scale up an ant by 100x, it's legs are ~10,000x as strong, but they have to hold up ~1,000,000x the weight.",
"This is why if you look at an elephant compared to an ant, the el... | [
"No. Just like how it also won't be able to lift 50x its own weight when it becomes human-size.."
] | [
"The biggest reason is the surface-to-volume ratio. If you made an ant 1000 times larger in each dimension, each leg would have a cross-sectional area a million (1000 x 1000) times bigger than previously. However, the volume of the ant would be a billion (1000 x 1000 x 1000) times bigger. Since mass scales with ... |
[
"Why do animals (like cats , birds and even rodents) look into my eyes when confronted, how do they know that's 'where i am'?"
] | [
false
] | null | [
"From wikipedia: \"One of the many hypotheses for \"causes\" of this diversification, the \"Light Switch\" theory of Andrew Parker, holds that the evolution of eyes initiated an arms race that led to a rapid spate of evolution\".",
"From ",
"here",
": \"you can see why it would be useful to know where your pr... | [
"Do you have any sources or readings about this? How do we know the animals can interpret our emotions, and how do we know animals recognize the faces of other animals. This sounds more like speculation than actual scientific analysis.",
"Edit: Thanks for the sources. Sorry for doubting you, but it's generally... | [
"Animals also recognize the faces of other animals, and because your face and especially eyes express non-verbal cues such as emotion."
] |
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