title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Would impacting Mars with its smaller satellite, Deimos, cause a substantial change to Mars's atmosphere?"
] | [
false
] | With all the subsurface ice being discovered on Mars recently, it seems a large influx of energy could be used to vaporize it and start a green house effect. Has impacting Mars with asteroids been evaluated as a possible tera forming strategy? | [
"I think there are probably larger problems with terraforming Mars than introducing a lot of water vapour into the atmosphere by de-orbiting Deimos.",
"The lack of a magnetosphere is one which can't really be overcome and would seriously hinder any sort of Earthlike-ecosystem that hadn't been radiation hardened."... | [
"The lack of a magnetosphere is one which can't really be overcome and would seriously hinder any sort of Earthlike-ecosystem that hadn't been radiation hardened.",
"The magnetosphere plays a minor role in protecting the ground on Earth from space radiation. It does have a longer-term role where it prevents atmos... | [
"Deorbiting Deimos would probably work by removing about 40% of its orbital velocity, which is 1.3km/s. Given it's mass of about 1.4762*10",
" kg then deorbiting it would take about ",
"95gigatons of TNT equivalent",
" of energy or about 950 ",
"Tsar Bomba",
" bombs at maximum yield (100 megatons each).",... |
[
"How does hearing work in animals with good hearing?"
] | [
false
] | I don't think being able to see well can really be a hindrance, and a super sensitive nose probably isn't a big deal either, but what about hearing? If an animal can hear really far/low volumes, does that mean everything at "normal" volume is deafening? Or is it not as simple as a simple multiplier being cranked up? | [
"Neuroscientist here! First, about vision and olfaction (smell): Highly acute senses can be more burdensome than you might think. ",
"Take vision, for instance: having good vision is actually kind of expensive, because of the brainpower required. Your brain consumes a lot of energy (about 25% of your resting meta... | [
"Well, part of the answer is that they can turn their head away from the source of the noise (since their hearing is often highly directional). But there are also mechanisms for damping loud sounds while maintaining sensitivity to quiet ones.",
"One such mechanism is the ",
"acoustic reflex",
", which involve... | [
"Very insightful thank you. I'm still wondering however, if they hear everything maddeningly loud all the time, or they can somehow tune out noises they don't want to hear."
] |
[
"What is the most widely accepted theory in the scientific community as to how life started on earth?"
] | [
false
] | null | [
"I think you need to clarify, do you mean single celled life, anaerobic, sea life, mammals or some stage in between?",
"I assume you are talking about the transition from chemical to protein through abiogenesis? If so, wikipedia has a good article discussing current popular theory:",
"https://secure.wikimedia.... | [
"Tricky proposition there....",
"At what point during abiogenesis did it stop being chemistry and start being biology? Was it a hard line or a big grey area? I would argue the latter. All biology is subject to evolution, no physics is subject to evolution, but chemistry? It's in the middle. ",
"Take those hypot... | [
"The most widely accepted hypothesis (it's too much to call it a theory, perhaps) is that life began in a soup of complex molecules as RNA strands. It's possible for RNA bases to form naturally under the right conditions, so it's conceivable that a short RNA polymer could also form, such a thing would tend to facil... |
[
"Would an octopus, or any other sea creature with tentacles, have a dominant tentacle?"
] | [
false
] | null | [
"It seems they actually do: ",
"http://www.3sat.de/page/?source=/nano/natwiss/145556/index.html",
" (sorry. it's german but here is the google tanslated version: ",
"http://translate.googleusercontent.com/translate_c?hl=de&rurl=translate.google.de&sl=de&tl=en&twu=1&u=http://www.3sat.de/page/%3Fsource%3D/nano/... | [
"I do not know about octopuses but starfish lead with a 'dominant' arm, but dominance can change throughout the day. Dominance is decided by which arm receives the strongest positive stimulus (e.g. food particles). For some species, dominance seems more fixed and rarely changes.",
"A little bit about starfish:",
... | [
"Google says \"probably\", here's an NPR link: ",
"http://www.npr.org/templates/story/story.php?storyId=92398531"
] |
[
"Why does protein from crustaceans look so different than land meat?"
] | [
false
] | null | [
"A muscle is not made of 'a protein'. Proteins are molecules after all, and even big molecules are VERY small.",
"Muscle tissue, like any other tissue, is made of cells and extracellular matrix. How it feels and/or tastes is dependent on a huge number of factors. There will be some chemical differences, but for t... | [
"All muscles are made of some combination of the proteins actin and myosin. Invertebrate and vertebrate muscles have different structures than each other so will have different qualities, including appearance. Other differences between animals such as blood type will also impact what muscles look like. But even ... | [
"How can the same protein look white amd mushy vs red and tough?"
] |
[
"Does temperature affect the half life of an isotope and the amount of radiation it releases?"
] | [
false
] | Since colder atoms vibrate more slowly, would this change the amount of radiation it releases? | [
"Check this out:",
"\n",
"http://www.whoi.edu/cms/files/1972AnRevNucSci22p165_68424.pdf",
"\nThis Annual Review of Nuclear Science published a paper on a large summary of effects of altering nuclear decay rates. The top of page 193 would be most relevant for your question: ",
"Except in the vicinity of pha... | [
"You vastly misinterpreted that last sentence. one part in 10",
" means an increase of 1.0001 times more. ",
" 10000"
] | [
"Ahah, thought that seemed odd; was in a bit of a rush. Edited, thanks!"
] |
[
"If a guy with 20/20 vision wears another guy's glasses, does he see what the other guy sees without glasses?"
] | [
false
] | null | [
"No, he doesn't. Let me explain how, I'll try to keep it simple but ask away if I don't explain something satisfyingly.",
"There are 2 major types of refractory anomaly called myopia and hyperopia (not counting other stuff like presbyopia and astigmatism for simplicity sake). These 2 are generally caused by a mis... | [
"Thanks a lot for this explanation!"
] | [
"So does this mean you can see what the other guy sees by turning the glasses backwards and looking through them?"
] |
[
"If the asteroid (2005 YU55) that just missed Earth scored a direct hit instead, what type of damages are we talking about?"
] | [
false
] | Would it be an extinction event for human beings? Winter for the next 100 years? | [
"Impact Calculator - Welp, there goes my workday."
] | [
"Impact Calculator - Welp, there goes my workday."
] | [
"On the debris of the Earth is an engraving of screaming humans encrusted with diamonds. It is of highest quality. "
] |
[
"If carbon dioxide is only 0.0391 percent of the atmosphere, how does it have such a big impact on climate change?"
] | [
false
] | Hi everyone, I have a teacher who believes that humans are not to blame for climate change and that climate change is not a real thing due to the fact that carbon dioxide only makes up a very small part of the atmosphere. I have tried to research this, but found conflicting results. Can you please help me to find an an... | [
"People often mistakenly conflate abundance with importance (not just with climate science, but with a lot of things). Consider this: iron makes up only about 0.006% of the mass of an average human. Yet, it is completely essential for us to live (without it the hemoglobin in our red blood cells can't transport oxyg... | [
"Your very absolute statement that ",
" argument based on lack of abundance implying lack of importance falls flat if I can provide an example where it isn't true: one cyanide molecule won't kill you so abundance does matter in ",
" systems.",
"You're misreading my argument. I said ",
". The argument: X is ... | [
"It's true that CO2 is a \"trace\" gas in the atmosphere. Ask your teacher if they'd be willing to drink water with a \"trace\" amount of arsenic. Then ask if they'd be willing to drink water with ",
" the \"trace\" amount of arsenic...It's still a trace amount, but can have significantly destructive effects. C... |
[
"If you add more nitrogen to the air, but don't take any oxygen away so you just raise the pressure, does a candle burn the same or whorse?"
] | [
false
] | Basically nothing changes. Everything is the same. You don't take anything away. Just add nitrogen. How does it affect burning? | [
"It means you need a bit more energy to heat up air. It makes things burn a bit worse.",
"In the opposite direction: Fire burns a bit better if you remove all the nitrogen.",
"A pure oxygen atmosphere is only really dangerous if it's at atmospheric pressure or higher (see e.g. Apollo 1)."
] | [
"The air is roughly 21% oxygen, 78% nitrogen and the rest is argon and other gases. ",
"If we simplify to say that the air is 20% oxygen at 1 atmosphere (atm) of pressure, we can say the oxygen has a partial pressure of 0.2 atm. (20% of 1 atm) ",
"If we were to add more nitrogen so that the pressure is now 2 at... | [
"I remember this argument in undergrad - I can see where the the other posters are coming from from a theory perspective but on a practical basis they are incorrect - you alter the fuel-oxidant mix by adding nitrogen and this can suppress fire even without removing the oxygen. I know fire suppression on board a sub... |
[
"In vitamin supplements they often provide 100% of the RDA or more. Why do they only contain 2% of potassium?"
] | [
false
] | null | [
"Hi ASIMOVSAGAN 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... | [
"Hi ASIMOVSAGAN 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... | [
"Hi ASIMOVSAGAN 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... |
[
"The Earth and Venus have an atmosphere. Our moon does not. Mars has a thin one, but Saturn's moon Titan has a thick one. How does Titan manage to hold onto a thicker atmosphere than Mars?"
] | [
false
] | It surely cannot be just gravity. How does Titan maintain its atmosphere where the moon and Mars cannot? | [
"What the other commenters say is not quite correct. Titan can hold its atmosphere because of its atmospheric composition and its low temperature. The magnetic field has only a small part in this. Basically what determines if an object can hold an atmosphere is if the components of an atmosphere can excell the esca... | [
"Being further out from the sun and protected by Saturn's magnetic field help curtail nonthermal escape, but probably the most important factor is that Titan is very cold. The reason low-gravity bodies tend to lose their atmospheres is due to Jean's escape: A given gas at a given temperature will have a random dist... | [
"The moon is too light, too close to the sun, and without a magnetic, field any atmosphere it has is stripped off almost immediately.",
"It’s a similar situation with Mars, but being a bit farther out and having higher gravity, Mars can hold onto a bit more against the solar wind. Plus, it’s atmosphere is mainly ... |
[
"If a door has three hinges, are the forces on each hinge (top, middle, and bottom) identical?"
] | [
false
] | null | [
"Let me make a few assumptions about your question first: Let's say that the door is uniform in density/weight, is open, it is not moving or being touched, the hinges are all connected to the frame and door leveled and are not offset in distance from the frame or door more than their own thickness, and when you ask... | [
"It is interesting to note that it is ",
" to ",
"not have the three hinges evenly spaced from the top and bottom",
", for mainly aesthetic reasons. It turns out that evenly-spaced hinges will look, from the usual eye-level perspective of somewhere between the middle and the top hinge, to be skewed towards th... | [
"In fact, one of the hinges is likely taking most of the weight. The two halves of each hinge are linked to the door and the door frame in a very stiff way. It would be enough to move the door side of a hinge a very small amount up or down to cancel the vertical load it supports, or, to the contrary, make it suppor... |
[
"I am teaching about graphs - What are some of the most important graphs in scientific history?"
] | [
false
] | null | [
"The results from ",
"COBE",
" would be my pick. The data points matched the theorised curve pretty much exactly, showing that the Universe used to be very hot everywhere - a very strong argument for the Big Bang theory."
] | [
"This would be my pick as well. ",
"Here's",
" NASA graph and explanation. The correspondence is so strong that it's impossible to tell the curves apart visually."
] | [
"Thanks! That's awesome :) "
] |
[
"What would the most average person be like?"
] | [
false
] | [deleted] | [
"European coloration is quite rare on the global scale, so your average person would be:",
"*hermaphodite",
"*dark hair",
"*dark eyes",
"*mid-toned skin",
"*since average features are the most attractive, this person would be be quite popular! ",
"In computer face averaging tests, women with averaged fa... | [
"This is not typicality, this is plurality. It's a shame NatGeo doesn't understand this distinction."
] | [
"Is that like the difference between Mode and Mean? Yea, I was slightly disappointed with their findings too. I was hoping for a composite sketch every ethnicity in the world. "
] |
[
"Can you date the age of earth without the use of radioactive isotopes?"
] | [
false
] | This is in relation to Hubble's law, and if they were able to date the age of earth during the discovery of redshift. My professor stated how initial measurements of hubble's constant were proven faulty since the earth would be older than the universe. However, during Hubble's time radioactive dating wasn't used. | [
"Well there are several methods that were tried and were wrong, very wrong.\nYou can ",
"read about them here",
". It includes methods ranging from thermodynamic cooling to salinity of the ocean.",
"Edit: Salinity wasn't actually included in the article, but it was one of the faulty methods used. It just does... | [
"I agree. the answer is basically, no. All other methods will just supply upper and lower bounds, and very poorly at that."
] | [
"First, we can use the age of Sol as an upper bound for the age of the Earth. Sol has a certain chemical composition that is directly related to its age - as the sun burns, it turns hydrogen into heavier elements at a rate determined by how bright it is, and we can measure what elements are in the sun by the light ... |
[
"Does the universe have a charge?"
] | [
false
] | [deleted] | [
"Here is a ",
"previous discussion",
" on this subject. The general consensus is that the universe is charge-neutral."
] | [
"Assuming our theories of baryogenesis are correct, all subatomic particles are formed by random quantum interactions that obey the laws of physics--the most relevant to this discussion being conservation of charge.",
"EDIT to clarify: if a charged particle pops into existence out of empty space, an oppositely-ch... | [
"I don't know if I should make this it's own post. But why is this and how did scientist come to find this out?"
] |
[
"Is my thinking on this thought experiment right? (dry ice in a balloon)"
] | [
false
] | If I put some dry ice in a balloon and put it on a balance what would you predict would happen to the reading on the balance as the dry ice sublimes and fills the balloon? Initially I would think that the balance reading would stay the same as the same amount of stuff is on the balance. But then think that the balance ... | [
"Actually, it would decrease. The mass does not change, but the it will have bigger volume and the Archimedes' principle applies."
] | [
"The balloon's weight would not change. The Archimedes force would increase (pulling the balloon up). Since the balloon is static, the reaction force would decrease slightly.",
"How precise is your scale? I estimate that the reading would drop by slightly more than 1 gram for every litre that the balloon's volume... | [
"Never seen it sold in any petrol stations near where I live. Why would they sell dry ice?"
] |
[
"Why do soft drinks/ beer taste so much better ice cold?"
] | [
false
] | null | [
"For beer, its because the beer you are (probably) used to drinking, american lagers, taste bad. At cold temperatures, you get less flavor, more cold refreshment. As the temperature increases, you start to take more of the flavor of the beer, and in the case of your typical american lagers, are not good flavors. ... | [
"That explains why the entire marketing of Coors Lite is based around it being cold. They have gone as far as temperature sensitive labels to let you know when it is cold enough to be able drink the stuff."
] | [
"Part of the explanation is carbonation. Gases generally (including CO2) become less soluble in water at higher temperatures. Ice really does serve a purpose because it makes the carbonation stay in the drink the longer the temperature is near zero C."
] |
[
"Electrical Theory: What the hell are vars?"
] | [
false
] | Look, this is embarrassing. I am an actual power plant control room operator and feel like I'm pretty good at it. This is the white whale of my knowledge; wtf is a var and why do I need to push vars out? Or maybe the term is Power Factor? Or Imaginary vs Apparent vs Real Power? All these terms have been used to explain... | [
"var means volt ampere reactive, wich is the unit of imaginary power. Imaginary power is (to use the most easy formulation) all power that is only present to change electric and magnetic fields.",
"For example a pure capacitor always has a current proportional to the change of voltage (C",
"di/dt=v)",
"if you... | [
"The equation to describe the behavior of an inductor is V(t) = L dI(t)/dt, essentially Faraday's Law. ",
"Assuming I(t) takes an exponential form like ",
"/u/RobusEtCeleritas",
" , and inserting your assumption of I(t) into the differential eqn, you will find that V is out of phase from voltage by pi/2.",
... | [
"What I'm understanding best is your last statement and I think what trips me up the most. What the heck is causing the phase shift in regards to induction motors or transformers? People keep trying to explain that it has to do with a field collapsing, but what does that actually mean?"
] |
[
"Are rod cells also used in photopic vision?"
] | [
false
] | There is a plenty of sources that states that cones are used to see colors under well-lit conditions (photopic vision) and rods are used under low-light levels, because they're more sensitive (scotopic vision). However, I can't find anything, whether rods are also used in good light conditions. (I'm sorry for any mista... | [
"The photopigments in the rods react faster than they can be recharged in bright light, meaning they get depleted. This is why after entering a dark area from a bright area, it can take up to half an hour for your night vision to kick in fully.",
"https://en.m.wikipedia.org/wiki/Rhodopsin",
"There are people wi... | [
"This is such interesting info, thank you!"
] | [
"What is the name of that congenital disorder?"
] |
[
"Can cancer be \"Transplanted\"?"
] | [
false
] | I'm no doctor, but I know that cancer can't be transmitted through means like sneezing or exchange in body fluids like other diseases, but I always wondered what would happen if one could extract cancerous tissue from one person and then put in someone else's body. would the cancerous cells "infect" the other guy? what... | [
"This is done experimentally in rodents as a model in research. It's super-effective.",
"In your scenario it wouldn't be as effective because of tissue mismatch, but it would still work in a lot of cases (if not most). Part of what makes cancer so cancer-y is that the tumor cells are assholes and don't listen whe... | [
"In my research we inject A549-luc lung cancer cells into the vertebral bodies of rats in a single metastasis model. We have to do this in athymic rats, since rejection of the transplant does occur and causes ",
" immune response that usually causes the death of the animal. ",
"I can only speak about cancer tra... | [
"What you describe is mediated through apoptotic pathways, which are usually broken in cancer tissue. IgG-assisted complement might kick in at some point, but that may or may not happen. The presence of tumor antigen may not be strong enough or \"found\" in the right ways."
] |
[
"To what extent is decrypting something an act of creation?"
] | [
false
] | [deleted] | [
"The act of decryption is not creation on the ground that only the original can possibly come out -- the same data that was encrypted, not changed in any way. So it's not creation, it is duplication, like a dry copy or a photograph.",
"No court that understands the issues will buy the idea that decryption represe... | [
"and my favorite xkcd comic about people being wrong on the internet ...",
"Mine too, although it 's hard to choose among the great candidates.",
"Surprisingly, my initial question may end being very pertinent depending on the approach I choose.",
"Yes -- but be prepared for the response that an intermediate ... | [
"and my favorite xkcd comic about people being wrong on the internet ...",
"Mine too, although it 's hard to choose among the great candidates.",
"Surprisingly, my initial question may end being very pertinent depending on the approach I choose.",
"Yes -- but be prepared for the response that an intermediate ... |
[
"Do hybrid and electric cars actually reduce overall human carbon emission?"
] | [
false
] | Obviously I'm no scientist, but it seems to me that since a large portion of our electricity is produced by burning coal and other fossil fuels that electric cars are more of a "not in my backyard" solution. Along with the fact that a car burning, say a gallon of gas would use that energy more effectively than what you... | [
"Starting with regular hybrids, those don't plug into the grid at all, so the coal argument is irrelevant. Plug-in hybrids do, but they are a very small subset of hybrid cars. Compared to normal cars, ",
"hybrids do, in fact, have a lower lifecycle carbon footprint than normal cars",
".",
"Now, as for elect... | [
"Glad to hear you found my work helpful! There's an enormous amount of misinformation surrounding electric cars, so I do my best to fight the misinformation.",
"Without knowing what state you live in so I can look up the local electrical grid mix, it's impossible to answer that question. However, if you take a ... | [
"I'm sorry, I just glanced at that one initially. I live in Louisiana, so its perfectly equl here(except way more fun). And I used to live in Alaska. That 126 mpg figure is pretty mind blowing."
] |
[
"Саn Тrаіnіng tо Весоmе Аmbіdехtrоus Іmрrоvе Вrаіn Funсtіоn?"
] | [
false
] | [deleted] | [
"Not that we know of. There have been some studies that showed differences in specific types of performance for left handed and right handed people. To my knowledge, there has been no conclusive research showing improved performance due to ambidexterity. In fact, developmental issues and reduced performance in some... | [
"What if you only started learning it as an adult? "
] | [
"It would definitely be an interesting research question, but as far as I know and could find in the research databases, there is no conclusive evidence in this area. I'll ask my professor(s) and get back to you."
] |
[
"Why is it called the 'special' theory of relativity?"
] | [
false
] | [deleted] | [
"Accelerating reference frames just make things more complicated but they are fine in special relativity.",
"The special case is no gravity = flat spacetime."
] | [
"The “special” case is flat spacetime. That means no gravity, but you can have accelerating frames of reference."
] | [
"Einstein's original paper outlining the special theory of relativity just called it the \"theory of relativity.\" It dealt with flat spacetime (Minkowski space) and covered everything to do with Lorentz symmetry (relative velocity, length contraction, time dilation, relativity of simultaneity, etc.) but it did no... |
[
"If we would go to the moon today - using and bringing with us the technological capabilities we possess now - what would differ from our missions some 40 years ago?"
] | [
false
] | What would we be measuring? Would we be looking for different things than back then? And so on... | [
"Insulating the wires powering the oxygen tank agitators thats for sure."
] | [
"For one thing, due to how politics have changed in the past 40 years, today's missions would have to be much ",
" safer. There was a very real possibility that the Apollo 11 astronauts wouldn't make it back from the Moon. Nixon had a ",
"speech",
" prepared and everything. Hell, they had to jam a ",
"ba... | [
"A good resource is the Lunar and Planetary Institute. This might be a good starting point: \n",
"http://www.lpi.usra.edu/lunar/strategies/",
"But you should also look at NASA's Planetary Science decadal survey: \n",
"http://solarsystem.nasa.gov/multimedia/downloads/Vision_and_Voyages-FINAL1.pdf",
"There, ... |
[
"What factors contribute to the acoustical activity (or lack thereof) of a piece of material"
] | [
false
] | Obviously there's the two most basic - longer and/or thinner = lower pitch, shorter and/or thicker = higher pitched - but what about factors determining timbre, sustain, pureness of tone, etc. In other words, why does a piece of leaded glass crystal dinnerware make a different sound than a metal cymbal or a wooden xylo... | [
"Shape and density are the biggest factors (in wires, tension and length are the most important). The pitches you get when you hit something are due to a natural instability in the object.",
"The natural vibration frequencies can be calculated, and are called \"modes\". The first (fundamental) mode is the lowest ... | [
"There are a lot of things about a material that lead to the sounds it can make. The two biggest are wave speed and geometry of the object. The geometry determines the wave shapes that the object can support (often called modes). For circular geometries you can expect modes that look like bessel functions, for rect... | [
"The first three paragraphs are good stuff. Unfortunatly for me, they're good stuff I already knew, but still good stuff. ",
"I have to disagree with you on your discussion of percussive sounds though. ",
"This video says more than I ever could about the range of percussion musicality beyond \"hitting two stick... |
[
"Question about gradual paralysis"
] | [
false
] | [deleted] | [
"It could be Guillain-Barre syndrome. I'd get it checked. I had a friend that almost died from it."
] | [
"The suggestion of GBS was probably based on the fact that it was an ",
" paralysis, which is very characteristic of GBS. So knowing where and how they were affected would be an important element in coming up with a diagnosis.",
"Progressive paralysis is usually indicative of an on-going pathological condition,... | [
"The suggestion of GBS was probably based on the fact that it was an ",
" paralysis, which is very characteristic of GBS. So knowing where and how they were affected would be an important element in coming up with a diagnosis.",
"Progressive paralysis is usually indicative of an on-going pathological condition,... |
[
"What does it mean, in a physical sense, to break symmetry when refering to the Higgs mechanism?"
] | [
false
] | I get breaking the mathematical symmetry of the standard model, and i understand the anecdote about a ball falling from a hat or bottom of a wine bottle like shape and thus breaking the rotational symmetry of the object, but i don't understand what this means in the physical/quantum sense. What symmetry is being broken... | [
"First, abandon the idea of particles and think of excitations of a field. That is, a field is something that has a value at all points in space. Some fields are scalar; their value at every point is a simple number. Some fields are vector; their value at ever point has a number and a direction. The vector bit is i... | [
"Incidentally, for a fantastic popular level description of the development of electroweak theory, the Higgs field and the people involved, read ",
"The Infinity Puzzle",
" by Frank Close. ",
"Also, you'll run into something called 'mixing angle' when studying this. In my simplified analogy, the mixing angle... | [
"Very easy to understand thank you, however i still don't get what \"breaking\" the symmetry means, is it because the higgs \"sticks\" to gauge boson that makes them unsymmetrical and thus massive? Or is it better to completely forget about symmetry in natural terms and simply say the higgs breaks the standard mode... |
[
"On 'Frozen Planet' David Attenborough said some birds migrated 11,000 miles for food. How do they know how to do that, and where to go?"
] | [
false
] | [deleted] | [
"I'm sure there are more knowledgeable folks here who can provide a more comprehensive answer, but ",
"there is evidence",
" birds navigate over such long distances in part by being biologically sensitive to the Earth's magnetic field. In other words, they have a built in compass. ",
"As for where to go, in... | [
"I'm confused. Does the question ask on how birds are tracked or how they migrate? "
] | [
"Ah I see... how do they do it? through natural selection over millenia"
] |
[
"Why are CRT monitors at 60Hz flickery, while CRT TVs at 60Hz seem just fine?"
] | [
false
] | I realized that when I watch a movie on a CRT TV, it doesn't seem flickery, even though the NTSC standard is 60Hz. However, if I set a CRT monitor to 60Hz, it seems to flicker a lot. Why is this? | [
"Remember you would sit much closer to a desktop computer CRT monitor than you would to a TV, and focus on detail that's much smaller than any text would be on a television.",
"So I think you would notice the flicker more with your ",
"peripheral vision",
", which is more sensitive to movement. This used to b... | [
"Part of the flickering is caused by you thinking that you're seeing it, because it's a desktop monitor.",
"The main reason why you're not seeing it on a TV, is that the TV very rarely has a perfectly still image for you to focus on. Your eyes are compensating for the lack of movement, by focussing on the still h... | [
"A lot of CRT TVs operate at 100-120Hz, even though the input is 50/60Hz, by displaying each frame twice. You could definitely see flickering on older TVs before they started doing that."
] |
[
"If my sunglasses have yellow lenses and reflect yellow light, why does everything appear yellow when I look through them?"
] | [
false
] | [deleted] | [
"The glasses actually absorb blue light, which means any light that goes through them looks yellowish. The reflections shouldn't be yellow, they probably just appear that way because the glasses let through a lot of yellow light that gets mixed with it. To test this you could look at a blue object in the reflection... | [
"The reflections shouldn't be yellow",
"Actually, that's what happens if something absorbs the blue light - whatever it lets through is yellowed and anything it reflects is yellowed too, because the blue has been absorbed."
] | [
"Sunglasses lenses have two different properties: reflectance and absorbance and they can in principle be independent of each other. You may coat the lenses with a thin reflecting layer that reflects some part of the spectrum. However that still doesn't completely determine what goes trough the lens to you eyes - t... |
[
"If I play music at the same volume on two speakers then will the overall volume of the music increase?"
] | [
false
] | [deleted] | [
"It is the dB scale. Equivalent Power = 10×log (10",
"+10",
" +...). Humans ears won't equate it to a volume doubling until it is 6-10 dB."
] | [
"When you have two noise sources it will be louder. It is essentially the same thing as having two light bulbs next to each other.",
"It does not add up directly though - it won't be twice as loud. If you have two noise sources with a sound level of 100 dB each the total will be about 103 dB."
] | [
"The important thing to know here is that \"loudness\" is a perceptual quality of sound, not a physical property. The apparent loudness of a sound is related in very complicated ways to the physical properties of the sound. Even for simple sounds like sine tones, the loudness depends on frequency as well as power... |
[
"From the perspective of a cell in the human body, how big would hydrogen look?"
] | [
false
] | [deleted] | [
"A cell is about 100 microns and a hydrogen atom is about 10E-5 microns. It would still be microscopic even if the cell were the size of a person."
] | [
"Right. A typical human cell sits around 20um or so, and we can easily see them under 5-10X magnification. "
] | [
"Right. A typical human cell sits around 20um or so, and we can easily see them under 5-10X magnification. "
] |
[
"Why do matrices raised to the power of 0 always give the neutral?"
] | [
false
] | null | [
"Your proof that A",
" = A only shows that it's true for n > 0.",
"It's not always true that A",
" = 1 for all matrices.",
"A",
" = A",
" = AA",
", which only has meaning if A is invertible. And if it's invertible AA",
" = 1. For a singular matrix like ",
"your example",
", A",
" isn't defined... | [
"Yeah I see, that bothered me, because at my University they said that that exact matrix is also 1 when raised to 0. ",
"However, your answer makes me wonder about mathematical induction. If I prove that inductive step is true for n+1, did I only prove it for positive numbers (or numbers greater than the base at ... | [
"Proof by induction is only intended to hold for natural numbers. I guess it could be extended to include all integers."
] |
[
"How did early astronomers know that those slightly brighter dots of light were planets? How did they know the order of the solar system?"
] | [
false
] | null | [
"What distinguished the planets from the stars for ancient astronomers was not their brightness, but the fact that some objects were always in the same relative positions to each other in the sky, while others moved around and could be found near different stars at different times. The ones whose positions were fi... | [
"Also, this would have been obvious to people, not something that only astronomers would discern after study. In the industrial age we've largely lost the night sky as a constant companion. Most people do not realize just how dark a moon-less sky is at night without any artificial illumination. It's incredibly dark... | [
"Planets are not necessarily always the brightest dots in the sky- Mars for example varies from a nondescript brightness to being one of the brightest things in the sky (based on if it's far or close to Earth), which is why its sudden brightnesses were attributed to its being a harbinger of war. What gives them aw... |
[
"How do we know about other dimensions if we can only understand the first three?"
] | [
false
] | I just don't really understand how people gather information about dimensions that we can not physically see. | [
"You can definitely treat time as a fourth dimension"
] | [
"Try reading the book Flatland. It's a little dry, but a quick read. If you can imagine how a sphere would appear to a two dimensional being, you can imagine how a 4 dimensional object would appear to us "
] | [
"Four."
] |
[
"I've obviously heard of people being born without hearing and sight, and less commonly smell/touch, but can we be born without other senses like proprioception or our sense of time without brain damage being a factor?"
] | [
false
] | To elaborate: is there a way someone could be born without being able to "feel" time or "feel" the position of things in relation to their body (knowing when they're about to touch their nose if their eyes are closed, etc.). | [
"All of these can occur. Anosmia is a lack of smell, which can potentially lead to life threatening situations (can't detect when food is bad, gas is leaking, smell of smoke, etc). While I haven't researched in people missing a sense of taste, they would encounter many of the same problems.",
"Problems with priop... | [
"I apologize for not posting an article, as I am on my phone, but-",
"\nThere was a case fairly recently where a girl was born without any ability to feel pain. Her parents had to constantly watch her because she would never cry if she was sick or had somehow hurt herself. Other than an inability to feel pain, sh... | [
"This disorder is called CIP, or congenital insensitivity of pain, it's often associated with in the inability to feel heat and cold as well."
] |
[
"Why do diesel engines blow black smoke when you turn them on but blow white smoke when you accelerate?"
] | [
false
] | null | [
"So the coloration of smoke is a basic indicator of the fuel ratio. Black smoke is more apparent on a cold start due to the intentional over-richening of the mixture. As part of the cold start cycle, injectors will put more fuel in than ideal in order to compensate for the lower internal temps. It also has the nice... | [
"I don't know how cold it is at OP's place right now, but when the weather is cold, since the air is pretty much saturated with water vapor, the water produced by the combustion simply condensates when it comes out of the exhaust, making \"white smoke\". This applies to both diesel and gasoline engines."
] | [
"Another reason to run richer mixtures is that (Taken from basic aviation knowledge) is that it means the engine runs a bit cooler than if it were run leaner."
] |
[
"How do caterpillars maintain basic bodily functions as they transform to butterflies within the chrysalis?"
] | [
false
] | null | [
"When a caterpillar forms a chrysalis to metamorphose, despite common misconception, a suite of enzymes doesn't literally digest the body down to a rich fluid to reform anew from scratch. Only some of their organs do that; the rest remain largely intact and simply undergo radical remodelling via cells undergoing pr... | [
"Fascinating read, thanks for the answer 👌🏼"
] | [
"At the Houston Museum of Natural Science butterfly center there is a huge, three pane display section where they have dozens of species of butterflies hatching. There are easily a hundred in there at any given time and they hatch all day. I used to love going in and watching kids marvel at a butterfly fighting out... |
[
"A \"biohacker\" with a PhD in biophysics says he's modified his DNA with CRISPR. What's the reality of this?"
] | [
false
] | Article here: | [
"Editing DNA with CRISPR is absolutely possible. But it kinda depends on what he means by \"modifying his DNA.\" Sure, you can change it in a test tube, or even in a living cell. But changing the DNA in every cell in the human body is still an impossibly tall order.",
"That day will come. But we're years, if not ... | [
"Not to mention CRISPR-Cas9 had an insanely high off target reads. You’re basically risking screwing up other parts of the genome to edit one gene. A new CRISPR-Cas13 is more promising but we’re a long way from true gene editing. "
] | [
"Which is not a very difficult or dangerous thing to do. Two MSTN genes that are pretty isolated. ",
"Difficult part is delivering the knockout to enough cells to make a difference in myostatin release. "
] |
[
"Are spurting fountains of blood due to swords hacking off limbs or heads realistic? If not, how much blood would be involved in a sword fight?"
] | [
false
] | Aside from Monty Python, Shogun 2 is releasing a "blood pack" to add more blood to the game. Which made me wonder, I know in the historical records they talk about rivers of blood, which I can see as feasible, I mean look at what happens during a whale slaughter. But I'm curious exactly how much blood would be spilt on... | [
"Blood squirting is feasible, if it's arterial blood, but a river? Perhaps in a mass death. The tide at Normandy beach was red for days after the invasion."
] | [
"It's definitely possible with arterial spurts. If you see videos of people whose throats were cut and had an artery in their neck severed you'll notice that blood spurts everywhere when their heart beats. I assume it's the same with removing limbs, thought it's incredibly unlikely that it's quite as drastic, and... | [
"Yes its realistic. ",
"http://www.liveleak.com/view?i=05ebe688b1",
" VERY NSFL"
] |
[
"Does the expansion of the visible universe cause some sort of exaggeration in the apparent distances between distant objects because their light is coming from a time when the universe was more compact?"
] | [
false
] | [deleted] | [
"I'm not ",
" sure that I understand your question. But I ",
" one answer might simply be to point out that determining the distances to other galaxies is ",
" a trivial exercise. The way one might guess — parallax, the same method you'd use to triangulate the distance to a reference point on the surface of t... | [
"What you're describing is the difference between the comoving distance and the proper distance which you can read about ",
"here",
"."
] | [
"Thanks!"
] |
[
"At the hardware level, how do computers multiply numbers together?"
] | [
false
] | I was learning about [adders](en.wikipedia.org/wiki/Adder_(electronics)) and I tried thinking how computers multiply numbers together. I haven't seen anything like an adder that works for multiplying, and the only way I could think of was looping the number through the adder a ton of times, for example, 5x3 would be 5+... | [
"A simple algorithm works by using the binary representation of one of the numbers (which is easy because numbers are already stored in binary inside the computer). For example, if b is 00100011 in binary then:",
"a * b = a * 00100011 = a * 00100000 + a * 00000010 + a * 00000001",
"Now, multiplying binary numbe... | [
"The simplest way is exactly how you mentioned; successive addition. An internal register holds the number of additions to make (one of the operands) while another holds the value to successively add (the other operand). once the correct number of additions have taken place, you have your result. This, as you right... | [
"Hmmm, that's ",
" algorithm that uses binary, it's not necessarily how a modern CPU uses it. A primitive Multiplier would use something like ",
"Booth's algorithm",
", a more modern one would use something like ",
"Wallace trees or a Dadda multiplier",
". And, of course, these are integer algorithms, for... |
[
"If hummingbirds have such high food demands, what do they do when flowers aren't blooming?"
] | [
false
] | see title | [
"They only drink nectar to give them the energy they need to hunt the bugs. ",
"The insects are their primary source of nutrients. ",
"The sugars in nectar and, well, sugar (in your hummingbird feeder) give them the calories they need to hunt for insects. They usually feed in the morning and evening, and especi... | [
"They also eat bugs, which isn't all that well known. They can also lower their body temperature to burn calories more slowly."
] | [
"They migrate to where the flowers are in bloom."
] |
[
"What do physicists mean when they say that gravity is the weakest of the four forces?"
] | [
false
] | null | [
"It means exactly that: out of the four forces, gravity is the weakest one. Gravity only seems strong because we live right next to a giant mass of rock and experience gravity all the time. When an entire planet worth of gravity is opposed to a small fridge magnet worth of magnetic force, the fridge magnet usually ... | [
"Per particle, gravity produces a much lesser force and is overpowered in all local contexts.",
"The entire gravity of earth isn't enough to overpower a common magnet holding an object up, it's not enough to overpower the strong nuclear forces of the nucleus. However, the strong force is short ranged, the electro... | [
"That's not electromagnetism, that's Pauli exclusion; electrostatic repulsion has basically no effect on making something solid, or else positively charged objects would be less solid than neutral ones. ",
"For a better example, a two-inch fridge magnet is able to completely overpower the gravitational pull of th... |
[
"How far off the moon would it take for one to be to not get drawn back to the surface because of gravity?"
] | [
false
] | This post...- ...got me thinking. If an astronaut were to jump off mount hadley in the picture, would they just float back down to the ground safely? Actually, that's kind of two different questions because I assume it's a lot further from the surface than mount hedley..? But hey! enlighten me :) | [
"There was a similar post about this recently. This may help.",
"http://www.reddit.com/r/askscience/comments/q88lw/how_small_would_the_moon_need_to_be_for_someone/"
] | [
"Very much farther than any mountain on the moon =P\nThere are a set of points where the gravity of the moon and earth balance exactly. These are the Lagrange points. You can google them. There are actually Lagrange points between the sun and earth as well. Very interesting places to put a refueling space station"
... | [
"How far off the moon would it take for one to be to not get drawn back to the surface because of gravity? ",
". With no velocity, no distance is great enough to avoid falling back. With enough velocity, the surface is high enough to assure no return to the surface."
] |
[
"I've often heard that leaving your cellphone plugged into a charger even though it's fully charged is bad for its battery life. Is this true? What about for laptops?"
] | [
false
] | Or is this something that only happened with old battery technology? Most people I know leave their laptop and cellphone charging overnight even if it's fully charged. | [
"Some companies don't design this into a system.",
"Lithium ion batteries ",
" overcharge protection because overcharging can cause thermal runaway, so I don't know what sort of laptops won't have this feature. Are there many laptops that don't run on lithium ion batteries?"
] | [
"What I mean is that some companies don't utilize advanced battery protective features.",
"It's impossible. Either you terminate the charge early (and in addition have better battery life when measures in charge-discharge cycles) or you have to switch into the constant voltage/delta I mode to \"top\" the battery.... | [
"There two ways to technically do it.",
"1) Charge the battery. When full, run off battery until X% discharged. Repeat.",
"\n2) Charge the battery. Bypass the battery.",
"Some older laptops used (1), which burns charge cycles and is generally not good. The better solution is (2)."
] |
[
"Zeno's Paradox"
] | [
false
] | [deleted] | [
"Put simply, just because there are infinite points to reach before reaching a key, that doesn't mean that reaching all of them will take infinite time. This is because while there are infinite points, they are also infinitely close to each other.",
"Wikipedia",
" has copious links to various historical and cu... | [
"In the same way that you are able to move at all, given that between every point that you could choose and your finger, there are always infinitely many points.",
"If space isn't discrete. It is unknown if space is discrete, but the assumption is that it is continuous."
] | [
"Numberphile has a great video about this: ",
"Zeno's paradox"
] |
[
"Why do LCD monitors have fixed refresh rates?"
] | [
false
] | Why wouldn't an lcd monitor just be able to draw at whatever rate the image data is coming in at? | [
"This is an appropriate question for askscience.",
"Anyways, a fixed refresh rate makes sense for LCDs. They hold their images between refreshes, so they don't \"flicker\" like CRTs do. You want the entire LCD screen to refresh at the same time, to eliminate \"tearing\" of the image, but you don't know exactly ... | [
"Why not? It's along the same lines as \"does whitening tooth paste really work?\". Already the majority of questions in this subreddit are physics specific."
] | [
"While I understand where you're coming from, I assume that there are engineers that are able to tell you the ",
" behind why LCD's currently do not (or can not) draw whatever rate the image is coming into. There are a number of other questions on ",
"/r/askscience",
" that I wouldn't call strictly science; ... |
[
"Is it possible to get yourself sick again by drinking out of the same water bottle you had drank from when you were sick?"
] | [
false
] | My roommate could be trolling me, he got me thinking it was possible, but it sounds retarded. | [
"If you get sick your adaptive immune system will build antibodies to that sickness antigen, if you are exposed to the same germs after your immune response to that same germ is started you can get infected but your body will be much much quicker in helping you"
] | [
"Chances are if you were sick and drank from a bottle by the time you were better again any bacteria etc that was left on the bottle will be long dead. "
] | [
"Well, I wasn't going to post since I didn't have any sources handy, but what is already here seems no better, so:",
"Although it is possible, it is quite unlikely. Most bacteria do not survive long outside of a nutrient rich environment (like you!) and someone correct me if I'm wrong, but I think viruses also te... |
[
"Could a piece of decaying radioactive material, properly contained in lead to make it's rad levels safe for humans, be used to heat eg. a house for many years, if placed in the floor?"
] | [
false
] | I've heard that decaying radioactive material creates heat. I'm not sure if this requires a controlled reaction or not (ie. in a reactor core), or whether heat output could cause criminality if something generating it was sealed in lead. Does AskScience know why this has never been tried? Is it the radiation problems, ... | [
"Sure, The plan you describe would work wonderfully, but there are some things to keep in mind.",
"First, the actual amount of heat generated would either be very little, but last a long time, or the opposite, with a great amount of heat being produced, but it will wane quickly.",
"The radiation would not cause... | [
"The heat is generated by radioactive decay. It is an uncontrollable physical breakdown of a radioactive isotope. No special reactions are required, other than whatever reaction you use to create the original radioactive material you are going to use in the first place. Your basic idea is sound in premise, but here... | [
"\"its\""
] |
[
"Why do hear little clickity clacks for a few minutes after I turn off my car from a long drive?"
] | [
false
] | null | [
"I'm not sure exactly which \"clickity clacks\" you are referring to, but it is most likely metal that was hot from the engine running, but is now cooling down and contracting. As metal contracts (or expands) it can make noises -- similar to the \"clacking\" that an electric baseboard radiator in your home will ma... | [
"That's possible, but most likely it's the exhaust system, since it gets comparatively hottest."
] | [
"Asked my mechanic once, this was it, the exhaust system cooling causes those pings, clicks, and clacks. "
] |
[
"Metal melted to liquid, then what?"
] | [
false
] | So I know when most metals (Iron, Aluminum, Tin) are heated to a certain temperature they melt and become liquid, but what happens if we keep heating the liquid? Does it boil? Does it evaporate? If it does become a gas, what happens when we continue to heat that? | [
"Metals behave like all other matter. Like ice, they will melt, then boil. ",
"If the metal is an alloy or compound of some other metals, first, that will break down (if it hasn't already) and then the metal will ionize. Ionization means that the electrons become disassociated from their parent nuclei because ... | [
"So metals melt, vaporize, and ionize like any other materials, this much is clear.",
"However, I'm not sure what you mean by \"break down\" for alloys. The phase diagram of most alloys includes a homogeneous liquid phase for all compositions (e.g., ",
"PtAl alloy",
", ",
"parent article",
"). That is, ... | [
"Here is a video demonstrating that, using UV light to cast a shadow from the vapor.",
"https://www.youtube.com/watch?v=lpZF88fqrl8"
] |
[
"Is wind chill convection or conduction?"
] | [
false
] | I always thought wind chill was the motion of the air against skin that caused increased heat loss, is this not an effect at all? Is this also conduction? From what I understand now wind chill is caused by the wind disrupting any insulating pocket of air, is this the case? | [
"If anything the motion of the air rubbing against your skin is heating you. Just not enough to make up for the steeper temperature gradient it is creating. When there's no wind you build a cocoon of hot air that insulates you better than your own skin. If it's windy you keep heating cold air since it's constantly ... | [
"Convection (in physics/fluid dynamics, not meteorology) is typically defined as heat transfer caused by moving liquids/gasses. This is sometimes split in free/forced convection, with forced convection indicating that the movement of the fluid is caused by an external force (wind, a fan, etc..) Conduction is the he... | [
"So, the heat is lost via convection because the air is moving, or the air is moving because of convection?"
] |
[
"Why is candle wax transparent when melted but opaque when cool."
] | [
false
] | null | [
"I has to do with crystallization in the wax. When solid, the long alkyl chains align and crystallize, and these crystallites scatter light which leads to higher opacity. When heated, the crystallites melt, and the resulting amorphous liquid no longer scatters light."
] | [
"I wonder if it's similar to tap water being clear as liquid yet cloudy as ice?"
] | [
"I suspect you're getting downvotes because you didn't contribute directly to the question, just offered a potential analogous situation. I think it's a fair point though. "
] |
[
"Why do moles grow such long hairs?"
] | [
false
] | Some moles grow hairs much longer than the surrounding area, why? | [
"They're called terminal hairs and we don't really know why they grow longer than normal hairs. They do appear to be influenced by hormones during puberty; so it could be that the mole hair follicle has a slightly different base level of receptors, or interacts differently with the bodies normal hormone levels."
] | [
"Also to note, if your mole has hairs in it, then suddenly loses the hairs it is worth getting that mole checked. ",
"A process that kills hairs in a mole can be an early sign of a melanoma, as the melanoma damages the surrounding normal tissue architecture, killing the hairs."
] | [
"Why are they called 'terminal'? That doesn't sound very nice."
] |
[
"If the earth 'wobbles' on it's axis, do geosynchronous orbits 'wobble' with it?"
] | [
false
] | Do sattelites in GS orbit follow a flat orbit, or do they wobble with the tilt of the earth? Would this have implications for a possible space elevator? | [
"The \"wobble\" that occurs of Earth's axis is so slow (over the course of 10s of thousands of years) that it shouldn't affect the geosynchronous orbits in any meaningful way. That being said, yes - over the course of those 10s of thousands of years, the orbits will shift to maintain their geosynchronous positionin... | [
"You have to remember that the satellites are already being affected by so many other forces and are constantly having to be repositioned within a box with a 70km side length."
] | [
"I was thinking of the \"Chandler Wobble\" ",
"http://en.wikipedia.org/wiki/Chandler_wobble",
"\nwith a period of 7 years - even though it's small, the distance to the GS orbital would make for a pretty big arc, no?"
] |
[
"Can you \"overdose\" on lemon?"
] | [
false
] | null | [
"We don't offer diet advice. If you have concerns, you need to speak to a medical professional."
] | [
"It's not a diet. I don't need help on diet. I think you made that assumption because I've used words \"detox\" and had daily plan. ",
"Can lemon juice in larger quantities have negative impact on your body?",
"What would happen if I ate 3-5 lemons for a month?",
"Would eating 5 lemons a day for an extended p... | [
"\"Diet\" by definition is what you eat, and yes, this is about diet. We don't offer diet or health advice. If you're asking \"Is this bad for me?\" then it's not appropriate for ",
"/r/AskScience",
". Please feel free to read the subreddit rules before submitting. "
] |
[
"Why are vegetables (mainly green ones) supposed to be good for you?"
] | [
false
] | Everyone is always saying how healthy green vegetables are for you, but what do they contain that could make them healthy? Usually, people will say vitamins, but if you already take a multivitamin that covers your needs, would extra vitamins and minerals in vegetables provide any extra benefit? Excluding fiber, it seem... | [
"1) a multi vitamin may be a start, but it isn't all your nutritional needs; infact you might just be wasting most of it making your piss more expensive",
"2) they are high in folic acid, and colored veggies usually are a sign of anti oxidants",
"3) every cell everywhere has a lipid bilayer, so there will still... | [
"I understand that the plants are made up of proteins and lipids but I think they may be indigestible: the nutrition facts for celery (",
"http://en.wikipedia.org/wiki/Celery",
") and broccoli(",
"http://en.wikipedia.org/wiki/Broccoli",
") show very negligible amounts of those macronutrients per weight. I b... | [
"(1) Fiber.",
"(2) Vitamins and Minerals. You could get these from multivitamins, but why would you pick the ",
" delicious way of getting these things? As highintensitycanada mentioned, a single multivitamin a day might not cover your needs.",
"(3) Antioxidants. Again, could get some from multivitamins.",
... |
[
"Why do we get headaches for so many different ailments? Why is it such a common occurrence?"
] | [
false
] | null | [
"headache is pain or discomfort in the head or face. Headaches vary greatly in terms of the location and intensity of the pain, and how often the headaches occur. The brain tissue doesn’t have pain-sensitive nerve fibers and doesn’t feel pain. But, other parts of the head can be responsible for a headache including... | [
"Well exactly my point. Why is it always a headache and not something more clear of \"I need more fluids\" or \"I need caffeine\" type message (obviously not a typed message clarity but just something a bit more defined than headache)"
] | [
"Well exactly my point. Why is it always a headache and not something more clear of \"I need more fluids\" or \"I need caffeine\" type message (obviously not a typed message clarity but just something a bit more defined than headache)"
] |
[
"Why do we use the 12-number system when speaking of time?"
] | [
false
] | null | [
"Babylonian math",
", which used base 60. We also have 360 degrees in a circle to thank for that."
] | [
"As far as benefits, the only one I can think of is it is easier to break up 60 or 12 into thirds than any decimal based systems. If an hour were split into 100 \"deciminutes\" some of the results would not be as nice as our traditional 60 minute system.",
"1/2 hour = 30 minutes or 50 deciminutes",
"1/3 hour = ... | [
"The Sumerians used Base 12 to count because they could use the three segments of the four fingers of a hand. That's most likely how they got 12, and originally only counted daylight hours. There's also conjecture that 12 comes from the number of lunar cycles in a year. The Egyptians divided the daylight into 10 ho... |
[
"Why is the time a medicine stays in your system measured in units of half-life?"
] | [
false
] | It seems strange to me that medicine is measure in the time it takes half of it to leave your system. Would it not be better to just say that a medicine will be completely out of your system in 20 hours than saying that half will be out in 10? Is it not roughly linear like that? | [
"Because when there is less medicine left, it takes longer to leave/dissipate. ",
"Think of it like a large tank of water with a hole at the bottom. The water will start to flow out of the hole pretty quick at first and then it would gradually slow down because less water above the hole would mean less pressure t... | [
"Because when there is less medicine left, it takes longer to leave/dissipate. ",
"Think of it like a large tank of water with a hole at the bottom. The water will start to flow out of the hole pretty quick at first and then it would gradually slow down because less water above the hole would mean less pressure t... | [
"Because when there is less medicine left, it takes longer to leave/dissipate. ",
"Think of it like a large tank of water with a hole at the bottom. The water will start to flow out of the hole pretty quick at first and then it would gradually slow down because less water above the hole would mean less pressure t... |
[
"I need some help applying to graduate schools"
] | [
false
] | [deleted] | [
"Go to the school's site and look at all the professors research interests, that should give you a guide to what they skew towards.",
"When I applied to grad schools, I basically started with the US News top 50 list, crossed off schools in places I wouldn't want to go, and then looked at the research interests li... | [
"I'm a PhD student in Australia (bioinformatics), and this seems quite different to how it seems to be done down here. Typically here, you'll contact the potential professor/research group leaders directly and talk/email/coffee with them, before any thought of applying via the university. We have no coursework in P... | [
"For mathematics, there aren't labs that you have to choose as an entering student, this could be different for the OP's case, which would mean that contacting professors is much more important. I didn't contact any professors at my chosen universities before I applied anywhere, for better or for worse."
] |
[
"Can you know the age of a single atom?"
] | [
false
] | I know you can estimate the age of many objects by looking at it's carbon 13 ratio. But can you know the age of a single atom? is it easier for larger atoms such as gold? | [
"Nope. Atoms are indistinguishable from one another. Two C-13 atoms look the exact same. Even assuming you know the decay constant exactly, it only means you have a knowledge of the likelihood of decay. Assume you have a single U-238 atom. It has a half life of 4.5 billion years. How would you go about measur... | [
"It doesn't always exist in a superposition. The wave function does collapse. You can say there are two atoms if they are not in a superposition. "
] | [
"I was under the impression that under quantum effects, atoms don't even have identities. That is, that one cannot say \"this atom\" or \"that atom\" as doing so really doesn't make sense at a quantum level.",
"Is that correct? If so, could you elaborate on that a bit?"
] |
[
"What are the effects of adding rock salt to a cooler full of ice?"
] | [
false
] | Background: I know some fishermen who do this, because it melts some of the ice, and the resulting liquid in there is as cold as the ice, and it quickly freezes the fish placed in the cooler. These same fishermen claim that the resulting slurry stays cold much LONGER than just a cooler of ice without the salt. They've ... | [
"Ice in equilibrium with (pure) water will stay at 0 degrees C. No higher and no lower. If you add salt to the water, the equilibrium temperature will decrease. So a brine ice mixture can be lowered below 0 degrees C. This lower temperature system would \"stay cool longer\" because it is colder.",
"It's as if the... | [
"It's the transfer of heat that's important.",
"The goal is to transfer heat away from the fish.",
"In the cooler, the fish is part of \"the environment\" that the melting ice will transfer heat from. ",
"The materials that the cooler is made of aren't good for transferring heat and there's not much else in t... | [
"By adding salt to the water you are increasing the number of dissolved particles in the water (this is quantitated as the molality of the solution). This decreases the freezing point of water and therefore the temperature of the ice/water mixture because it will always equilibrate at the freezing point of water as... |
[
"If an astronaut travel in a spaceship near the speed of light for one year. Because of the speed, the time inside the ship has only been one hour. How much cosmic radiation has the astronaut and the ship been bombarded? Is it one year or one hour?"
] | [
false
] | null | [
"You get the full year's worth of radiation.",
"From an outside point of view, we see that time is dilated and the astronaut is moving very slowly inside their spaceship. But we see the spaceship take a full year to reach its destination, and gets hit by all this radiation along the way.",
"From the astronaut's... | [
"You get the full year's worth of radiation.",
"Wouldn't it be a lot more? If I get hit by distant starlight, I don't care much. If I get hit by starlight that's blue-shifted into gamma-rays - that's not very healthy.",
"So the physiological effects should be a lot more than just the accumulation of the year's ... | [
"Right - like I said, it's not quite as simple as my first explanation implies."
] |
[
"Why is Coulomb's law so close to inverse square?"
] | [
false
] | I was reading a physics text recently that mentioned that early on, experiments showed that Coulomb's law was inverse square to a very high degree of accuracy. I'm wondering why the power would be so close to 2, and if there is any deeper theoretical justification for that. Does QED offer an explanation of why Coulomb'... | [
"Just in terms of the experimental limits, the results don't suggest that the force law is something very close to two but slightly different, but rather that it is experimentally consistent with two to within a certain accuracy (",
"~10",
"). The search for a deviation from two yields a null result."
] | [
"At very short distances, the force law is no longer simply 1/r",
" due to charge screening effects a/k/a scaling of the coupling constant."
] | [
"fishfly is correct. One needs to add to Git's argument two facts:",
"Then the argument works. These facts are important, because the weak nuclear force violates the first, and the strong nuclear force (QCD) violates the second."
] |
[
"Why do different species of birds sound different? Is it learned or is it to do with their physical makeup?"
] | [
false
] | null | [
"for nearly all bird the sound of their tweeting is genetically determined. a good example is the cuckoo... it is raised by non related foster parents but tweet in their typickal cuckoo-way. \nsome species can adapt and learn new sounds. eg. parrots, ravens, starling, etc. can learn to talk. there is also a bird th... | [
"it's a mixture of both. the vocal organ of birds is different then ours: we mammals use vocal chords whereas birds have the so called syrinx: its a hollow organ at the base of the trachea. sound is modulated by vibrations of the walls of the syrinx (called membrana tympaniformis) and the pessulus (sits at the fork... | [
"Thanks for the reply! Do the genetics determine the bird's physical makeup or the way it uses the same parts as others? If that makes any sense"
] |
[
"Does anyone have a good, intuitive explanation of what the word entropy means?"
] | [
false
] | I know that it's related to the amount of information needed to define a system, but I can't find a satisfying definition. From Wikipedia: "...entropy is defined as the amount of additional information needed to specify the exact physical state of a system, given its thermodynamic specification." What does it mean by '... | [
"This is the purely thermodynamic point of view :",
"'Given its thermodynamics' implies that quantities like pressure, volume and total internal energy of the system are known. However, this does not constitute complete knowledge of the system because thermodynamic systems are generally composed of 10",
" atoms... | [
"I don't agree with Marsupial's need to cite sources in this case. This concept is basic and found in an introductory text to physics or thermodynamics. It would actually be somewhat silly to find a random undergrad text just to cite it as a source for obvious common knowledge.",
"An unpaneled response is perfect... | [
"Entropy is a way of measuring how reversible a process is. If a process is fully reversible without external energy input then it creates no entropy. If it is not reversible and requires energy input (or more energy than can be extracted from the original process) to reset to its inital state then it creates entro... |
[
"Are there species with more than 2 sexes?"
] | [
false
] | In humans the X and Y chromosomes decides the biological sex. Are there any species where theres more than 2? I found previous discussions where birds were said to have 4 genders and 2 sexes, but I would guess its still only 2 chromosomes at play. I wanted to know if there can be more. | [
"In the evolutionary literature, \"sexes\" are defined in terms of different sized gametes (egg/sperm). There are many forms that unequal gametes can take, but we don't observe a third \"intermediate\" gamete in any species. Presumably, sperm and eggs are well optimized for their differing roles/benefits (mobility ... | [
"Very true, but those are intersex conditions which are often pathological and don't result in a discrete and distinct sexual phenotype. "
] | [
"Are you talking about ZW-sex determination? Not all birds are ZW and also a few other organisms such as insects, some lizards, etc. are also ZW-determined. While it is true that ZW does have two main sex chromosomes at play, do not confuse the number of chromosomes with the number of discrete sexes. For example... |
[
"We are scientists from the Society of Vertebrate Paleontology coming to you from our 75th annual meeting. We study fossils. Ask Us Anything!"
] | [
false
] | Hello AskScience! We are members of the . We study fossil fish, mammals, amphibians, and reptiles — anything with a backbone! Our research includes how these organisms lived, how they were affected by environmental change like a changing climate, how they're related, and much more. You can learn more about SVP in or . ... | [
"Adam Pritchard - A vehement no and a cautious yes. Ross doesn't seem to spend much time reading about paleontological discoveries, traveling into the field, or engaging in actual research. He's too busily engaged in relationship drama with Rachel to really read much into therapsid evolution.",
"HOWEVER, I distin... | [
"100 duck sized horses, because then I might be able to look into growth patterns, natural variation, and all sorts of other things that require a larger dataset. - S. Drumheller"
] | [
"I could have sworn you went extinct in the Cretaceous... It's good to know you are alive and well. Also, props for being able to type with such tiny forelimbs"
] |
[
"Why is the water clearer in the caribbean than in the Gulf of Mexico?"
] | [
false
] | I'm spending my honeymoon in the British Virgin Islands. The water here is absolutely beautiful. It's very clear and you can see very deep. Whenever I spend time on the beaches of the Gulf of Mexico, the water is much darker and you can't see deeper than a few feet at most. Is it simply different plant and animal life?... | [
"The Caribbean is much more nutrient-poor than the Gulf. The Gulf is heavily affected by the nutrient input coming from the Mississippi dumping water filled with nutrients and other particles picked up from traveling over land. The Amazon delta is the same way. There is also less circulation in the Gulf, so the ... | [
"Where in the Gulf of Mexico are you referring to?",
"I live in New Orleans and can tell you the silt and mud that comes out of the Mississippi is so vast that it stretches all the way from mid texas to beyond gulf shores so you've got to go a bit beyond that to hit the really clear waters. "
] | [
"Mainly Gulf Shores. That makes a lot of sense, actually. Thanks!"
] |
[
"Why do we need to postulate the presence of dark matter? Wouldn't unexpected astrophysical phenomena simply indicate that our understanding of gravity in inadequate?"
] | [
false
] | It seems to me to be a great jump to postulate the existence of a new type of matter in response to astrophysical observations not lining up with predictions as dictated by current theory. Would not the more parsimonious response be to work on modifying the theory? Do we really need dark matter to explain our observati... | [
"People seem inordinately bothered by dark matter. Dark matter is evidence that our understanding of gravity is good, not the other way around.",
"Let me begin with another situation. You hear your doorbell ring, yet when you go to look, there's no one there. Do you suppose that there must be something new ele... | [
"We infer the presence of things from their gravitational influence all the time -- the exoplanet and black hole examples were precisely that, and for a great classical example, the presence of Neptune was inferred from deviations in the orbit of Uranus. Which is more natural: that the orbit of Uranus needed a new... | [
"As a physicist working in a completely different field, I appreciate your answer so much.",
"People tend to forget that everything we measure or experience is generally ",
", but their measurable effect. Even for very ordinary things like when you reach your cup of coffee, you are guiding yourself trusting the... |
[
"Why is there so much diversity of life in the ocean, when all \"sea creatures\" are evolving in the same place?"
] | [
false
] | There are a ton of different and very diverse species of life in the ocean (jellyfish, sharks, dolphins, seahorses, crabs) but they are all evolving in the same place (correct me if I am wrong). What conditions or variables make them evolve differently? | [
"Good question! Let me take a stab at it. It's late, and I'm drunk - so expect this to be scattered slightly.",
"The answer lies in the fact that they inhabit different ",
"ecological niches",
" - essentially, a niche is the role they play in the ecosystem. ",
"Even though all of the life is evolving in the... | [
"The ocean is massive and the earth is 70% water. You could ask the same question about the diversity of life on land and consider that evolving in the \"same place\". But in both environments there are many different variables that put selective pressures on the different species that inhabit them. In the ocean... | [
"Yeah, so picture you're an organism in an environment that's saturated with those sponges (this probably wouldn't happen either, but baby steps!). ",
"You're a sponge, and you undergo a mutation that makes you have to compete LESS with all the other sponges. You're likely to be more successful than the other spo... |
[
"How exactly does alcohol induced heart failure cause tiredness and breathlessness?"
] | [
false
] | I can't get my head around the exact mechanism for these two symptoms occurring. Is it just because the heart is weakened and therefore less blood is going to the muscles (tiredness?). But with breathlessness there must be an element of the oxygen/carbon dioxide transfer between the lungs. Could someone clarify in as m... | [
"I think there are a couple of reasons... As the heart fails, fluid backs up in the lungs. This decreases the volume of airspace available for exchange. In addition, though, this adds to the weight of the lungs and a decrease in its compliance so the work of breathing increases. The latter contributes to the fatigu... | [
"Thanks. Would you be able to be more specific in the mechanism of fluid backing up and the decrease in volume? Is it to do with an inflammatory response of the lungs caused by the build up of blood in the left ventricle? "
] | [
"Let's go through it one step at a time. Alcohol causes a dilated cardiomyopathy meaning over time the heart muscles stretch out which at the same time thins them out. Because it stretches out, it holds more blood in its chambers, but the fact that it is thinned out (aka it has less muscle per cm",
" ) means the ... |
[
"If iron makes blood red, what would make blood other colours?"
] | [
false
] | I think some spiders have green blood due to copper, but are other colours found in nature, or even possible? | [
"hemocyanin",
", which contains copper, is blue.",
"hemerythin",
", which has iron, is pink.",
"chlorocruorin",
" also has iron and is sometimes either green or red."
] | [
"Other colors can found in nature, and they can be caused by....the iron in your blood! It's not just the presence or absence of iron that causes teh color of blood, the color is also strongly effected by the oxidation state of the iron. The ",
"color of hemoglobin",
" is determined in part by whether there i... | [
"To go along with the explanation others have given, here's a ",
"pic",
" to show the subtle difference between the two."
] |
[
"What will happen to a rock floating through space as the universe goes through heat death?"
] | [
false
] | I understand that in an isolated system entropy tends to increase, but I’m having trouble picturing what an increase in entropy of a space rock would look like. Is a space rock constantly losing molecules on its surface as time goes on, and eventually there’s no rock left and the molecules also break down? How would th... | [
"In a conventional heat death scenario, the rock cools off asymptotically to absolute zero, any defects in the crystal lattice will anneal away until it is almost a perfect crystal, atomic diffusion morphs it into a perfect sphere (the minimum energy shape gravitationally), and eventually quantum tunneling will all... | [
"Thank you for taking the time to type this out"
] | [
"👉😎👉"
] |
[
"problems with alcohol help?"
] | [
false
] | null | [
"Hi FJNK12 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... | [
"Hello,",
"We can't advise you about this here."
] | [
"and on what subreddit then?"
] |
[
"What does being cold feel like, its not painful, but what about it makes it uncomfortable?"
] | [
false
] | [deleted] | [
"There are receptors on the surface of cells that are activated by changes in temperature. These receptors allow ions to move across the cell membrane when changes in temperature occur, essentially generating an electric current that is detectable by the nervous system and interpreted as a sensation of cold or hot ... | [
"So interesting. Thanks!!"
] | [
"This is way deeper than I ever thought I'll know. Thanks!"
] |
[
"How sensitive is a dog's sense of touch on the pads of it's feet or through it's fur?"
] | [
false
] | null | [
"Veterinary Technician here. The pads of dog paws are much like the pads of our feet. When we walk around barefoot often, they get calloused and rough, whereas when we are not barefoot often, our feet are softer and more sensitive. Dogs who go on walks/hikes/are outdoors often will have tougher pads, while the smal... | [
"I've seen a dog wimper in pain cause it's owner was walking it on pavement in the heat of the day."
] | [
"Skin has pressure sensors and tickle sensors, amongst others, so the pressure doesn't transmit through a callous while vibrations still do.",
"\"pressure doesn't transmit through a callous while vibrations still do\" You understand how that statement kind of contradicts itself right? "
] |
[
"How does the Earth retain its magnetic field despite the high temperatures in the core?"
] | [
false
] | [deleted] | [
"The Earths magnetic field is not the result of a solid-stade magnet in the core. It is rather the result of the rotation of the solid metal inner core in relation to the liquid metal outer core, which generates an electro-magnetic field. The process in not unlike an electric dynamo."
] | [
"The exact behavior and processes at work are still under study, and there is still quite a lot of research going on the finer détails; so the jury is still out on this one. As you can imagine, \"access is problematic\" as they say...",
"I'll link you to some research on the topic, but keep in mind this reasearch... | [
"The Earth's magnetic field is created through a dynamo. Dynamos are really cool, and they're (for example) how we make electric power -- but the easiest way to understand them is a little different than you picked up in high school physics. Instead of thinking about ",
" being induced in a dynamo (the practica... |
[
"When I close my eyes, am I flexing or relaxing my eyelid?"
] | [
false
] | null | [
"You're not doing anything to the eyelid; what you are doing are flexing/relaxing muscles connected to it.",
"Now the general rule for muscle antagonism applies here: so opening ",
" closing eyes involve ",
" relaxation of one muscle and contraction of another (similar to the relationship between your biceps ... | [
"This one?"
] | [
"You are contracting the ",
"orbicularis oculi muscles",
" when you forcibly close your eyes."
] |
[
"Are we aware of the location of neurological signals relative to the brain?"
] | [
false
] | Let' say you get an itch on your thigh. You are aware that the itching sensation came from your thigh, but how? I assume that specific nerves correspond with locations all over your body. Now let's say you close your eyes so that you cannot visually see the location where the itching is coming from (your thigh). You ca... | [
"Let's say I took a vibrating tuning fork and held it against your little toe. The sensation of this area of your body is covered by a specific dermatome (",
"http://en.wikipedia.org/wiki/Dermatome_(anatomy)",
"). So, all of the sensation you feel there will go back to one level of your spine (",
"in this cas... | [
"There are receptors for several different kinds of stimuli (pain, hot, cold, light touch, etc) all over your body. These receptors send signals toward the spinal cord via synapses (connections between neurons), and then usually on to the brain. Each receptor serves a certain space on your skin (the surface area th... | [
"So is this proprioception responsible for amputees knowing where their \"arm\" is after it is amputated? As in, they feel where it is?"
] |
[
"How many percent of the incoming radiation from the sun are emitted by earth?"
] | [
false
] | I recently took a multiple-choice exam where this question came up. The 'correct' answer turned out to be 100%, but this doesn't sound right to me. I know that the Stefan–Boltzmann law says, two black bodies are in thermal equilibrium if the emitted power is equal. However earth is not a black body and some of the inc... | [
"It's very, very close to 100%. Photosynthesis accounts for a relatively tiny amount of energy absorption, and is just about a net-zero game anyway, because most plants will eventually be eaten or burned, converting that chemical potential energy back to heat.",
"So unless your multiple choice test had answers li... | [
"The question, as I interpret it, was asking how much of the incoming radiation to the Earth gets re-emitted. Since the Earth is in thermal equilibrium (in broad strokes, i.e. its average temperature over long periods of time doesn't change much), it must be re-emitting the same amount.",
"What you're missing is ... | [
"That doesn't sound right, because the Earth also has an internal energy source from radioactive decay. If the sun provides about 1400 watts/m",
" to half the planet and the Earth is about 20 Celcius then it radiates about 400 W/m"
] |
[
"How can cheese be \"aged\" so long, but when it's in my fridge for longer than a few weeks it goes mouldy?"
] | [
false
] | null | [
"Aged cheese wheels have something called a \"rind.\" Rinds are most obvious on a cheese like brie. Some cheeses are also waxed on the outside (think Gouda.) It's basically an outer dehydrated shell that is maintained by the cheesemakers, and either one certain type of edible mold is allowed to flourish on it (like... | [
"Mozzarella!"
] | [
"What’s your favorite kind of cheese to make?"
] |
[
"How small can a star be?"
] | [
false
] | null | [
"In terms of mass, objects below 80 times the mass of Jupiter are not big enough to ignite hydrogen fusion and are classified as brown dwarves. Objects below about 12 times the mass of Jupiter are not hot enough to fuse deuterium.",
"In terms of radius, neutron stars are extremely dense and can be below 10 km in ... | [
"I think it's worth noting however that bodies such as white dwarves and neutron stars do not function at all like our sun does. ",
"In active stars like our sun, additional thermal energy is constantly being generated through fusion reactions. However, in white dwarves and neutron stars, no fusion reactions ar... | [
"You may be interested in ",
"this lecture",
", it's all about brown dwarves, 'rogue' planets and other small, dim bodies."
] |
[
"Are sound waves effected by other sound waves?"
] | [
false
] | null | [
"Yes, sound waves can interact with other sound waves through destructive and constructive interference. If the frequency match in phase and pitch, then they would be amplified. If they differ in phase, then they would cancel each other out. ",
"It is how noise-cancelling headphones work ",
"http://en.wikipedia... | [
"Usually? No. Sound waves that are small compared to atmospheric pressure obey the principle of superposition. That is, the sound field from two sounds together is equal to the sum of the sound fields created by those waves individually.",
"However, if sounds waves become very loud, they can become strong shockwa... | [
"To add a small explanation to this: when a physicist says \"something affects something else\" they mean that the two things change due to the interaction. We would say that sound waves that merely interfere do not interact: two sound waves that move in perpendicular directions and interfere at some location simpl... |
[
"If I get my epigenome sequenced, can I only get a representative sample of my epigenome if I got tissue samples from every region of my body?"
] | [
false
] | null | [
"It depends on what you want to use it for. If you are trying to detect a disease or pre-cancerous cells, then you need to sequence every at-risk tissue (which for a non-specified cancer, would be every one). If you are just curious about epigenome heredity, then inherited epigenomic elements should be present in... | [
"I would take those epigenetic elements with skepticism however. Since they are, by definition, epigenetic, they are prone to modifications that alter the expression levels on this persons genes. So, even if he does get samples from each tissue, they are likely to be less stable over time and would therefore not be... | [
"I agree. This was a difficult question to answer without understanding what the application was. Epigenetic elements can be very transient and they serve tons of different roles in biology on several different timescales."
] |
[
"Can anyone ID this weird animal?"
] | [
false
] | [deleted] | [
"Praying mantis egg case (after hatching), I think. "
] | [
"Ootheca",
".",
"Mantids and cockroaches lay oothecas, although some give live birth.",
"Cockroach egg sacs typically are not adhered to a surface, but are usually carried around by the female until hatching takes place.",
"Mantids usually deposit an egg case that adheres to wherever it is laid."
] | [
"You're welcome. Always happy to ID a bug-related thing!"
] |
[
"Space Battle with Today's Technology?"
] | [
false
] | I was rereading Ender's Game, and I started thinking about what would happen if, today, an alien species attacked us (a la the Buggers). Would we just be completely overwhelmed? Do we have any weaponized systems that could stand a chance, or would we be able to build anything in time? I assume the alien civilization wo... | [
"If they can just accurately chuck rocks from the distance of the moon then the earth has no chance. ",
"They can easily take out nearly all our space infrastructure with (dumb) pebbles or even sand. We can't even get anything out of low orbit without massive work.",
"A few nations have the capability to take o... | [
"A good example of warfare from the moon is Robert Heinlein's The Moon Is A Harsh Mistress. Absolutely excellent battle in that book."
] | [
"To talk about something like this there are two things we should be considering; how far this race has traveled to get here, and how complicated it is to travel such a long distance. We should be able to assume that based on our observation methods of space, and that we haven't found any other civilization out the... |
[
"Why exactly do refracting lens magnify electromagnetic radiation?"
] | [
false
] | null | [
"They don't really magnify it like you might be thinking... They're not making something small into something bigger (ie., less energy into more energy). They're simply redirecting the things coming into the lenses into a smaller area. That's focusing."
] | [
"Yup. It's like how a shovel can turn a bunch of sand on the beach into a big pile. It didn't make more sand, it just moved it over here. Now there's less of it over there, but you got a big pile, and that's what you wanted. "
] | [
"They superimpose the signals by bending the path the signal takes so more of the signal is found in the same area. This is the general idea for a concentrating lens. ",
"If however the lens characteristics are of the divergent type the signals will be diffused over a wider angle and appear to be weaker.",
"N... |
[
"Why are moles often the site of skin cancer? Doesn't more melanin mean more protection from the sun?"
] | [
false
] | null | [
"No science background so I may get kicked off this thread but...",
"Moles are usually the result of your skin cells having a small mutation that results in small, abnormal growth. Many moles aren't dark in the way that you're referring and just look slightly reddish. Other similar mutations are sometimes referre... | [
"Geneticist here, and that is a good answer! To expand on that, the defining characteristics of all these various skin lesions are the type of cell affected, how it's affected, and which layer of skin the cells are in.",
"While melanin does protect from UV exposure, a mole, or \"nevus\" in medical terminology, ha... | [
"The \"more melanin\" in moles that progress to cancer are often due to abnormal proliferation of melanocytes (the cells that produce melanin). In the case of moles that progress to melanoma, the melanocyte proliferation has been caused by DNA mutations caused by repeated insult from UV radiation. So in short, the ... |
[
"since the comoving distance remains constant, is the observable universe a shrinking sphere, when looked at in this comoving frame?"
] | [
false
] | I'm trying to wrap my head around the observable universe concept, and faster than light speeds etc. And an answer to this question would help with that. Also, why is the OU always displayed as an oblong sphere, rather than a perfect sphere. Does it have to do with the, I'm guessing, flat side being on the axis towards... | [
"Maybe it just adds some artistic expression, or because people expect it to look like that, or because you're looking at a sphere spread out into a 2D surface, maybe even because it's easier to see objects that aren't hidden behind things in our own galaxy so the distribution of known objects is a bit skewed . Th... | [
"the big bang happened everywhere",
"This is weird (not saying wrong!) :) ",
"I always envisioned the big bang happening, throwing away matter in all directions eventually. with all matter being spread out moving away from the center of the explosion (but, if i understand you correctly, the big bang was a tiny ... | [
"It sounds like you're thinking of the Big Bang as a stone dropped in a puddle and everything expanding away from that point. It's more like a balloon getting blown up, our universe is the surface of that balloon, every point is expanding away from every other point. The universe was infinite when the Big Bang oc... |
[
"Is there any species where unfertilized eggs can sit dormant for a long time, similar to spores?"
] | [
false
] | null | [
"I'm not entirely sure what you have in mind, but eggs in human females just sit around... Oocytogenesis is complete before birth. "
] | [
"I'm thinking of fish, where they lay eggs that are fertilized externally. Is there ever a situation where eggs are laid that can be fertilized significantly later?"
] | [
"I don't know of any species that has this ability with ",
" eggs.",
" ",
"But there are ",
" species where fertilized eggs stop development and exist in suspended animation (diapaused embyros) until external conditions are right to continue developing/hatching. ",
"In fish its more often seen in species ... |
[
"Why are most people right handed?"
] | [
false
] | Why are most people right handed? Is it due to some sort of cultural tendency that occurred in human history? What causes someone to be left handed instead of right? And finally if the deciding factor is environmental instead of genetic, are there places in the world that are predominately left handed? | [
"So I actually study handedness on a day to day basis and I will try to cite some of the newer research that has been coming out. Most of what I've found thus far is behind pay walls as many of the articles are very new and I've heard most of this research at conference presentations up to this point.",
"So there... | [
"One common theory, as to how handedness affects the hemispheres, is the brain hemisphere division of labor. Since speaking and handiwork require fine motor skills, its presumption is that it would be more efficient to have one brain hemisphere do both, rather than having it divided up. Since in most people, the le... | [
"More theories on the promotion of left-handedness.",
"A 1988 survey found that in 30 of 33 publications, infants who had undergone birth stress were significantly more likely to be left-handed. Lower Apgar scores — a measure of a baby's overall condition at birth — have been clearly associated with left-handedne... |
[
"Rotating spacecraft, artificial gravity problem."
] | [
false
] | If I am not mistaken, the "rotating spacecraft" solution to artificial gravity uses centripetal force to keep its inhabitants on the ground. Even if this simulation of gravity is perfectly matched to that of the earth, what would keep someone or something from flying due to weightlessness if it was knock off the surfac... | [
"Objects in motion tend to remain in motion. If something is moving tangentially at a high enough speed, and then jumps, it's still moving at that speed tangentially."
] | [
"If I were standing at the surface and jumped straight up, wouldn't I be weightless? I understand that I would move along with the surface, but one of the great things about earth is that it exhibits a pull on its inhabitants. I can't fathom why this artificial gravity would exhibit the same pull."
] | [
"I can easily picture water in a bucket, however, I am still struggling. I think a hypothetical situation would help explain it. If I were stationary some distance away from the surface of the sufficiently big rotating cylinder and I were to throw a ball the same velocity a human would fall out from a distance of a... |
[
"It's been about 5 years since the Mochizuki's ABC Conjecture proof was originally published. What's its current status?"
] | [
false
] | null | [
"Relatively recently, one of the few who claim to understand how the proof works put out a brief summary to help guide those who are trying to decode it. ",
"This summary is 300 pages long.",
" More people are beginning to get an understanding of it, and it has been determined that, correct or incorrect, the id... | [
"Just to add some perspective:",
"Mochizuki published some really important articles proving several important cases of Grothendieck's anabelian conjectures in the middle of the 1990's, which are quite hard and technical and relies on several previous articles that are also quite technical.",
"He has since then... | [
"I don't know much about pure mathematics at research level, but would it be possible to get a computer to verify the proof?"
] |
[
"Do we really need the Id?"
] | [
false
] | null | [
"I'll answer your question, but won't release it to the general sub. First of all, I have to note that the conceptualization of Freud's psyche (Id, Ego, Superego) is outdated. Modern psychologists/psychiatrists no longer recognize it as a valid concept. ",
"That said, psychoanalysis does still exist in the form o... | [
"According to Freud, there were two ways that humans seek satisfaction: the basic, primal instincts of the Id (that I described above) and the moral and civil supremacy--the ability to fit into civilized society--that satisfied the Superego. Most often, these were in conflict with each other. For example: You find ... | [
"Well, plausibility does not equate to accuracy.",
"The simplest answer is that the personality--what Freud called the 'psyche'--is far more complex than to be distilled down to three main drives (morals, satisfaction, and balance). Personality psychology continues to struggle to find a theory that adequately des... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.