title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Why does the moon appear to be bigger sometimes?"
] | [
false
] | I've come across several different answers to this question and I don't know which one is true (if any). Is it an optical illusion? If so, what causes that? Is it because of the moon's orbit? If so, why is the moon only bigger when it's closer to the horizon and not when it rises a bit more? I know nothing about scien... | [
"http://en.wikipedia.org/wiki/Moon_illusion",
" <- Wikipedia has a great article on this"
] | [
"Exactly--it is an optical illusion.",
"The significant effect that you notice is it looks large when there are small distant objects in the background, and much smaller when there are no foreground objects when its high in the sky. If you see distant mountains in the background that are smaller than the moon, y... | [
"..which explains how it's yet unexplained."
] |
[
"Does the recent drought in California pose a threat to the Redwood or Sequoia forests?"
] | [
false
] | As I understand, the Redwood forests are in more of a temperate rainforest environment, whereas the Sequoias are in a drier environment. So, does the drought pose a threat to either of them? I could clarify by saying specifically the old-growth trees and forests, since I kinda doubt this specific drought would actually... | [
"Actually the giant Sequoias and redwood forests obtain a large amount of their water needs through the nocturnal fog that is prevalent in the northern California area during the dryer summer months. Its one of the reasons these trees are able to grow so much taller than simple ground water absorption would allow. ... | [
"Fascinating, thank you for the link!"
] | [
"Some of these trees are several thousand years old, and have probably lived through dozens or hundreds of such droughts. "
] |
[
"Do spiders have nerves in their silk glands?"
] | [
false
] | I saw about a spider getting "milked" and wondered if spiders can feel, when the silk leaves their body? | [
"Yes spiders do have nerves in their silk glands, that's how they're controlled. If you're asking does the spider have nociception in their silk glands, i.e. \"is doing this hurting the spider\" then the answer is slightly more philosophical. ",
"They likely don't feel the same emotional suffering in response to ... | [
"ok thanks, but i wasnt neceserrely asking for pain, but rather for a general sensation, that something is leaving their body.",
"I shouldve maybe worded the question better, sorry."
] | [
"thanks for the answer! that was what i was lookinh for. Maybe someone with knowledge from this field can confirm this.\nBut thanks amyway :-) "
] |
[
"Do our bodies make antibodies with multiple paratope configurations for the same pathogen?"
] | [
false
] | The SARS-COV-2 virus has many different unique epitopes. When a person gets infected, does their body actually make antibodies with multiple different paratopes? In other words, does a body's antibody response actually consist of various antibodies with various differing paratopes binding to various different unique ep... | [
"Yes, your body will create several different antibodies in response to a pathogen. These antibodies will all bind the virus tightly, as that is what is selected for during antibody development. However, not all of these antibodies will actually be effective in clearing the infection, depending where on the pathoge... | [
"I had a hepatitis B test lately, the standard now is to do two Elisas, one of them to detect whether you have antibodies that bind to core proteins (you’re infected) and the other is to detect whether you have antibodies that bind to surface proteins (you’re vaccinated)."
] | [
"I had a hepatitis B test lately, the standard now is to do two Elisas, one of them to detect whether you have antibodies that bind to core proteins (you’re infected) and the other is to detect whether you have antibodies that bind to surface proteins (you’re vaccinated)."
] |
[
"If the Moon's gravity is ~16 % of Earth's would the height of a jump be proportion to one on Earth?"
] | [
false
] | Just wondering if injury would become an issue. | [
"It's not completely accurate that you would land with the exact same velocity as if you jumped on Earth. Due to the moons lack of atmosphere, the drag coefficient would be zero. Thus your jump would take you slightly higher (drag slows you on the way up as well as the way down). You final velocity on the moon woul... | [
"Yes. But so can jumping to maximum on Earth. The additional velocity due to the lack of drag would be minimal for a person jumping. Bodily damage during landing would more likely be the effect of landing technique and body condition.",
"Drag would play a large roll in other situations. A baseball thrown at 90 mp... | [
"With less gravity, you would jump 6x higher on the moon than on earth. While it seems like jumping ~8 feet in the air (space?) would result in an injury on landing, you would land with the same velocity as you had when you jumped.",
"You're jumping higher, but it's because you're falling slower, not because you... |
[
"Is it possible (or likely, moreover) that there are deep see creatures out there that have individual lifespans of hundreds or even thousands of years?"
] | [
false
] | Editing to add: thanks for all the responses so far, I've learned a lot from y'all already. The immortal jellyfish are fascinating. I had recently read about the Greenland Shark and some really old tortoises, which is what drove me to ask this question. I guess I'm most curious about what lies deep in the ocean, perhap... | [
"There are species we know of (both ",
"deep water",
" and ",
"shallow",
") with lifespans in the hundreds of years. Some species are even ",
"biologically immortal",
" and could theoretically live for thousands of years, although they may be killed by predators or some other cause before then."
] | [
"It's not just likely, it's well documented and almost too much to fit in a single comment. ",
"To start with there are bacteria buried in sediments that are still living and some scientists claim they might be 100 million years old. Now, that's an astonishing claim and I don't know if I entirely believe it rig... | [
"A quick list I can think of:Greenland shark, quahog clam, immortal jellyfish, ocean vent tube worms I think.",
"You would also probably like to learn about the lithosphere. It is the ecosystem that exists in subterranean rock (and I dont mean caves, I mean in the solid rock.). There are species from 100s of mete... |
[
"Why can't we use momentum to reach light speed?"
] | [
false
] | null | [
"Physics"
] | [
"Physics"
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"To check for previous similar posts, please use the subreddit search on the right, or Google site:reddit.com",
"/r/askscience",
" ",
"Also consider looking at ",
"our FAQ",
... |
[
"Is the sonic boom created by a jet caused by the sound of the engine/air friction or the actual displacement of air by the moving object."
] | [
false
] | My basic knowledge of physics begins to get a bit muddy on this subject, but as i understand it, the sonic boom is similar to a wake created in water when objects disturb the surface. I'm wondering how the sound created by an object (in this case, a jet engine) serves to amplify the effect of the sonic boom (if it does... | [
"When an object passes through the air it creates a series of pressure waves in front of it and behind it, similar to the bow and stern waves created by a boat. These waves travel at the speed of sound, and as the speed of the object increases, the waves are forced together, or compressed, because they cannot get o... | [
"Right, so the actual air being displaced by the object due to friction would cause pressure waves/sonic boom?"
] | [
"Correct. Another example of something that creates a sonic boom but is not powered by an engine is the cracking of a whip. The whip is designed so energy sent through it causes the thinner part to move faster and faster until it gets to the very thin cracker at the top which moves at speeds > 760 MPH causing a min... |
[
"Someone throws a pot of boiling water at your torso. You have two choices: normal 100% cotton t- shirt or no shirt. Which is better?"
] | [
false
] | I've always believed that it would be much better to have no shirt -- while it would hurt, you could immediately wick away the water with your hand, whereas a cotton shirt would absorb the hot water and keep it close to your skin. Are there other factors? | [
"I'd rather be sans shirt considering this is water and 100% cotton, it's going to make the cotton stick and thus make it more difficult to remove, increasing the time you're in contact with high thermal energy.",
"I don't know if anyone can provide sources that prove this is accurate however."
] | [
"Some of the water will penetrate the larger pores of the shirt and come into contact with your skin, while some of the water will be absorbed into the fibers of the cotton. ",
"Arguments in favor of the shirt:",
"The shirt will absorb some of the thermal energy, limiting the amount that reaches your body",
"... | [
"While I appreciate what you're suggesting, keep in mind that you're dealing with 100C, not 70, so considerably warmer than that chart you've provided, so the burns are worse, and faster.",
"A big consideration with burns as well is the depth and penetration of injury, and the shirt, being that it's going to be m... |
[
"I've always had electricity and magnetism explained to me as very closely linked forces. Are magnetism and electricity separable forces? That is to say, can you create one without the other?"
] | [
false
] | I know you can generate electricity chemically as well as a host of other ways without magnets, but can you create electricity without creating some amount of magnetism? Conversely, can you create a magnetic field without generating some amount of electricity? | [
"There are two different aspects to this question depending on what observer is answering.",
"For any given observer, it is possible for them to both create an electric field without a magnetic field (any static distribution of charge will do it) and a magnetic field without an electric field (permanent magnets, ... | [
"which in reality is \"powered\" by electron movement",
"This need not be true at all.",
"Ferromagnetism (the type of magnetism appearing in a permanent magnet) usually does not come from the ",
" of electrons; it comes from their ",
". Spin is not a motion in the sense that you normally think of it, and sp... | [
"Can you create electricity without creating some sort of magnetism?",
"Not in any really useful way, no. A moving electric charge in a wire (a current) creates a magnetic field around the wire.",
"You can create magnetic fields without generating electricity. Those fields just need to remain stationary, and on... |
[
"Does the order of operations have an deeper significance, or was it a convention that was simply agreed upon?"
] | [
false
] | null | [
"It is a convention but you could consider it to have deeper significance. ",
"Addition, multiplying and exponents are all repeated applications of the former operation",
". Multiplication is repeated addition (4×3= 4+4+4) and exponentials are repeated multiplication (4",
" =4×4×4). ",
"You preform expon... | [
"I have never had it explained so simply before. I always had trouble remembering because I never got the why, but this made sense! Thank you!"
] | [
"It's a notational convention only, albeit a very convenient one since it makes writing polynomials easy."
] |
[
"How closely do feral domesticated animals resemble their original wild ancestors?"
] | [
false
] | I was wondering specifically about recreating or imitating extinct species by encouraging modern descendants to become feral. | [
"There is a difference between taming and animal and domesticating it. \"",
"Domestication",
" is the process whereby a population of living organisms is changed at the genetic level, through generations of selective breeding, to accentuate traits that ultimately benefit humans. A usual by-product of domesticat... | [
"I suppose that was the idea, selecting for traits in the reverse fashion as what the animal went through when domesticated.",
"\nIf domestication makes the animal dependent, how do any animals become feral then? Why do they not simple die?"
] | [
"some animals we've changes so much to the point where they cannot fend for themselves anymore, mostly because of predation. Many domesticated animals often escape and take over the population, such as horses, goats, sheep, etc. if there are no natural predators they do fine. Pigs can become feral rather quickly, b... |
[
"A more specific term for executive function depletion?"
] | [
false
] | I am studying for the GRE after being out of school for two years. I am working full-time, spending 2-3 hours a day in GRE study, working out, while attempting to eat healthy. What I have noticed is I severely deplete my common resource of self-regulation and executive function where I sometimes need a day or two of re... | [
"It's called Ego Depletion",
"http://en.wikipedia.org/wiki/Ego_depletion"
] | [
"And the only reason I know that as an exercise scientist is because it's one of the most important concepts in getting people to habitually adopt exercise habits - they are significantly more likely to continue to exercise if they do it first thing in the morning because they have a \"full tank\" of mental ability... | [
"Just a note that the ego depletion literature was ",
"called into question",
" recently. This meta-analysis identified serious issues of publication bias, and the authors argued that it may be necessary to go back to testing if the ego depletion model is actually correct before applying it.",
"Another issue ... |
[
"How are some people able to climb Mt Everest without supplemented oxygen?"
] | [
false
] | [deleted] | [
"Studies of the Sherpa people that live and work on the mountain show they have certain genetic traits that are expressed allowing their body to adapt to high altitude",
"Right. That's why our best mountaineers, including Reinhold Messner or Göran Kropp, don't even come close to the Sherpas in the matter of survi... | [
"Studies of the Sherpa people that live and work on the mountain show they have certain genetic traits that are expressed allowing their body to adapt to high altitude",
"Right. That's why our best mountaineers, including Reinhold Messner or Göran Kropp, don't even come close to the Sherpas in the matter of survi... | [
"I am not sure if this would apply to the persons you have listed however obviously, we already know that the more red blood cells we have the more oxygen that can get to your cells. At high altitudes there is less oxygen in the air - so people who live near mountainous regions as a result of natural selection have... |
[
"Have any satellites been planned for interstellar observation?"
] | [
false
] | I noticed that all the satellites launched so far have had a goal of studying our solar system. Voyager 1 is now outside the solar system but as people mentioned it's not moving very quickly because it was designed to study planets in our solar system. Others commented that the time to reach Alpha Centauri would be dec... | [
"A chain wouldn't work because of the speed of light. Alpha Centauri is 4.37 light years away. It would take 4.37 years to send and recieve information no matter what, relay or no relay. You can't circumvent the speed of light."
] | [
"I was thinking about signal strength and power consumption here. Power reqs increase by square of distance as I recall."
] | [
"You're right, it would take a lot of power to send a signal to another star. We might be able to use the Sun as a gravitational lens to focus radio waves from an interstellar probe:",
"http://www.centauri-dreams.org/?p=10123",
"one tenth of a milliwatt is enough to have perfect communication between the Sun an... |
[
"AskScience AMA Series: We're three experts on plastic pollution who have worked with Kurzgesagt on a new video, ask us anything!"
] | [
false
] | Modern life would be impossible without plastic - but we have long since lost control over our invention. Why has plastic turned into a problem and what do we know about its dangers? "Kurzgesagt - In a Nutshell" has released a entitled "Plastic Pollution: How Humans are Turning the World into Plastic" today at 9 AM (ED... | [
"I just have 4 questions to try to simplify it both for myself and to explain to others",
"Thank you for doing this!"
] | [
"Yes, it was discovered last year that a type of worm called the wax worm (the larvae of the wax moth) has the ability to break down polyethylene (PE). PE accounts for around 40% of global plastics. ",
"PE is largely non-degradable, but there have been a couple of previous instances where particular bacteria or f... | [
"I think putting the responsibility on individuals is a lie, really. ",
"\"Stop obsessing with how personally green you live – and start collectively taking on corporate power\"",
" ",
"Edit: I'm happy with the ",
"official answer",
"."
] |
[
"What exactly is happening when you get chills?"
] | [
false
] | null | [
"Sorry no useful info, but I think he's referring to just getting a short, temporary chill often referred to as a \"cold chill\". I always get mine while I'm taking a nice relaxing piss."
] | [
"The latter is essentially the same concept as the former. When you have a fever, the hypothalamus wants the body to be in at a higher temperature, like at 38C instead of the normal 37C. Shivering is how the body obtains the newer, higher temperature."
] | [
"You're shivering. Essentially, hundreds of tiny muscles are all contracting and relaxing at once. The purpose of this is to generate heat when you're cold.",
"When you get a cold/fever, your body's thermostat (hypothalamus) decides that it want the body's base temperature to be higher. So it tells your muscles t... |
[
"What about Gödel's incompleteness theorems are so groundbreaking? Wasn't the idea that math and science are based on unprovable axioms around since Descartes?"
] | [
false
] | null | [
"Very short answer:",
"You're misunderstanding Godel's (1st) incompleteness theorem. It doesn't say axioms are unprovable, you're right, that's an accepted part of mathematics. ",
"It says any set of axioms of arithmetic cannot be both consistent and complete. In very simple terms this means \"there are no 'per... | [
"And for the [I don't know how many times], I have to downvote this interpertation of Gödel's theorems, which is false and (unfortunately) consistently upvoted to the top.",
"A statement isn't true in a vacuum. It is true ",
". Moreover, by Gödel's completeness theorem, if a statement is true within an axiomati... | [
"Also partially false. If you take the theory of a given model (the theory of arithmetics on natural numbers, for instance), it will be both complete and consistent. However, if such a theory is complex enough to allow interesting mathematics, then it won't be generated by a reasonnable set of axioms in first order... |
[
"How is usable energy extracted from a fusion reactor?"
] | [
false
] | A fission reactor ultimately heats water to produce steam to spin a turbine to generate electricity. I assume a fusion reactor ultimately heats water ....>>.... generate electricity. But how do we get from a hot plasma in a tokamak to heating water? How do we get from inertial confinement to heating water?? | [
"Neutrons generated in the fusion reaction escape the magnetic confinement due to their charge neutrality. These are absorbed by layers outside the confinment chamber, and since they carry the majority of the energy released in the reaction, allow for energy extraction.",
"AFAIK, heating the coolant via these neu... | [
"I guess my question, which is an engineering question, is \"How are heat exchangers built into fusion reactors?\"",
"In a tokamak reactor, are there cooling pipes built into the walls of the reactor that pull heat away for use?",
"And for an inertial confinement reactor I've got no idea.",
"Are these problem... | [
"I guess my question, which is an engineering question, is \"How are heat exchangers built into fusion reactors?\"",
"In a tokamak reactor, are there cooling pipes built into the walls of the reactor that pull heat away for use?",
"And for an inertial confinement reactor I've got no idea.",
"Are these problem... |
[
"Someone please explain space-time?"
] | [
false
] | I understand that universe would be made up of a field of space, but where does time come in? | [
"Let me offer a first step in this process by asking you to think about rotations on a plane first, and then turning to spacetime. This isn't short, but I've tried to make the logical flow clear, and I think it answers your question of why time enters into the picture.",
"So let's thingk about looking at objects... | [
"Spacetime is 4-dimensional, it has 3 dimensions of space and 1 of time. Don't think of it as the in the pictures you see. So when something with mass/energy bends the space-time not only is the space affected but time to, so essentially time will move slower around objects with larger mass."
] | [
"Thanks to both of you. I understand it a whole lot more now. "
] |
[
"When I watch star wars or star trek I noticed the ships look aerodynamic. Wouldn't it be better to make them as small as possible instead of long triangle shaped fighters?"
] | [
false
] | null | [
"http://i.imgur.com/BWDHE.gif"
] | [
"http://i.imgur.com/BWDHE.gif"
] | [
"Regardless of aerodynamics the ships need to look cool on screen, and they need to be identifiable as something akin to contemporary planes and ships.",
"Some of these ships also need to fly in atmosphere(s) (e.g. the battle at the start of Star Wars Episode III) so it makes sense for them to be aerodynamic."
] |
[
"How do white colored LEDs work?"
] | [
false
] | Isn't white light a compendium of many various colors of light? How does the LED express this? Aren't LEDs only capable of producing light of a single wavelength? | [
"The most common type of white LEDs are based off of single-color blue LED chips. The chip is coated with a layer of phosphorescent material that absorbs some of the energetic blue light, and converts it to lower-energy red and green light.",
"You can see how this works by looking at ",
"a typical LED spectrum"... | [
"One way is to use multiple LEDs. The outputs of each LED are then adjusted until white light is produced.",
"The other way is to coat a single LED in a variety of phosphorescent chemicals. When a molecule is excited (by absorbing a photon, perhaps) it can spontaneously decay to its ground state by emitting a pho... | [
"Do you know what an example of the phosphorescent material could be?"
] |
[
"Would a person weigh more at the pole than at the equator?"
] | [
false
] | I ask because it seems the centrifugal force would be greater at the equator than the the pole, effectively reducing the force of gravity at the equator. This question is assuming the Earth is a perfect sphere (which I know is not the case). | [
"Assuming a spherical earth there would be a difference resulting from the earth's rotation. So yes, you would weigh slightly more at the poles than at the equator. ",
"Now for the earth as an oblate spheroid there is the same difference, plus you will weigh even less at the equator because you'd be farther away ... | [
"Earth's equatorial radius is 6,378.137 km, and its polar radius is 6,356.752 km (a difference of just ~21 km). Not very big, given that 21 km is just 0.3% of the equatorial radius. The difference in Newtonian acceleration due to gravity between the equator and the pole can be calculated as follows:",
" = GM*(1/(... | [
"The oblate spheroid does 2 things. Further distance from center of mass AND increased tangential speed, both of which reduce your weight.",
"You're not wrong in any way, just adding that both aspects of the oblate spheroid make you weigh less."
] |
[
"Can blind people have visual hallucinations?"
] | [
false
] | Or, if a blind person tripped on acid, would all of their hallucinations be auditory/other? | [
"Yes. In ",
"Charles Bonnet syndrome",
" an individual who lost their sight late in life because of macular degeneration experiences complex visual hallucinations. An important note here is that these individuals are not fully blind, but retain some parts of their visual field.",
"The reason I say that it dep... | [
"For the first question, I don't know. Blindness has a very broad definition, and usually involves some visual processing being present. People with anophthalmia who are born without either eye can have some visual processing ability (there may be enough nerves spared that can pick up on brightness change). The eff... | [
"Our mind is built to construct a 3D model of the space we are occupying because it is essential to moving within it. ",
"To counter this, how would a blind person describe an elephant based on touch alone?"
] |
[
"How does an individual work on conquering a phobia like vertigo?"
] | [
false
] | null | [
"Step one is to look up the definition of vertigo.",
"Now then if you are talking about acrophobia you have to remember that it should be irrational or overly extreme. Most people would be uncomfortable pinned to a ledge on a cliff and stomach lurching is a reasonable response to death being a snapped rope away.... | [
"OK, that's interesting, thanks.",
"Sorry if it's too close to medical advice, I don't plan on getting therapy for it so much as wondering what the therapy consists of. "
] | [
"I was always told that the fear comes from still being connected to the ground. That's why you don't feel the fear when riding in an airplane. "
] |
[
"Is my understanding of cryptocurrency correct?"
] | [
false
] | My terminology will be very off, but do I have the general idea right? It was explained to me that there is basically a program that everyone agrees to use to test if a number is a valid "coin" or not. The numbers that will pass as true through this program are very difficult to figure out because they are very large a... | [
"I'll assume you are referring to Bitcoin specifically. (There are other cryptocurrencies.)",
"Generally the mining process you've described is correct. The basic notion is that there is some \"proof of work\" -- a problem that is hard for everyone to solve but easy to check the answer.",
"This is not the whole... | [
"So what is a node? What does a solution look like? In my mind, I imagine a massive grid of possible solutions that everyone is trying and it is just a matter of iteration since you cannot predict where a correct solution lies. How far off is that view?"
] | [
"Your intuition is correct about solutions. Bitcoin uses a hash function that we believe to be cryptographically secure. This means that if you are given some value x, it is impossible to come up with a value y such that f(y) = x in polynomial time. Bitcoin asks you to find a value y that will produce an x that is ... |
[
"That feeling that you're being watched: is there any basis to it?"
] | [
false
] | null | [
"The short answer is \"no\", at least not in any psychic/paranmormal sense. Rupert Sheldrake has done a lot of \"research\" on the matter but, as with much paranormal research/exploratory studies showing positive results, the quality and methodology of such research is frequently called into question due to ",
"c... | [
"Obviously there's no paranormal explanation, because the paranormal by definition doesn't exist.",
"It raises an interesting question, though: If there's ",
" to the feeling, though, why does such a feeling exist in the first place? "
] | [
"There has been some research on the topic:",
"Many animals use cues from another animal’s gaze to help distinguish friend from foe [1,2,3]. In humans, the direction of someone’s gaze provides insight into their focus of interest and state of mind [4] and there is increasing evidence linking abnormal gaze behavio... |
[
"What is the biological/neurological explanation of \"mania\" or \"frenzy\"?"
] | [
false
] | [deleted] | [
"\"Frenzy\" behavior is common in many species, mammal and reptilian.",
"Such behaviors are usually associated with mating, group defense, or food procurement, the latter most often among predators.",
"Although the precise neurochemsitry is up for grabs, it is wholly feasible and probable that it can be trigger... | [
"So induced frenzy as seen in many religious rituals is basically the art of psychologically \"tricking\" your body into thinking there is danger/sex in the immediate area? Could the feeling of religious \"ecstasy\" be the endorphins released with no actual danger?",
"Also, do you know what exact branch of scienc... | [
"I would think neuroscience or psychology."
] |
[
"Why do your ears make a ringing sound when the room is dead silenced?"
] | [
true
] | [deleted] | [
"Nerves can become sensitized and experience after effects. Also, you're used to hearing noise. Dead silence is something the nerve endings don't necessarily know how to interpret and they try to hear \"something\". ",
"I couldn't find the studies I was looking for to answer this, but this study on ",
"the brai... | [
"Audiologist here",
"This phenomenon is called tinnitus. It is the \"ringing\" that some people can hear inside their head. Unlike like it's spelling suggests, it is not an inflammation of any nerve, it's etiology is relatively unknown. Tinnitus can have different types of sounds for different people. Tinnitus ca... | [
"In the movie Children of Men Clive Owen is subject to a loud explosion at close range. A little later on Julianne Moore says \"Y'know that ringing in your ears? That 'eeeeeeeeee'? That's the sound of the ear cells dying, like their swan song. Once it's gone you'll never hear that frequency again. Enjoy it while i... |
[
"If I have the flu, and I am next to my dog coughing and what not, why doesn't he get the flu?"
] | [
false
] | null | [
"The epithelial cells in his respiratory tract and his erythrocytes don't have receptors for the virus. The influenza glycoprotein hemagglutinin needs to bind to a cell surface molecule known as sialic acid inside its human host. "
] | [
"Thank you!"
] | [
"Jesus tapdancing christ that was fast. You just happened to know that? You either work for the CDC or should."
] |
[
"How do those disposable thermometers at the doctor's office work?"
] | [
false
] | Whats the exact mechanism allowing them to read temperature? How is it so accurate? | [
"The Tempa-Dot thermometers contain material with slightly different melting temperatures. \"By varying the ratio of two organic chemicals that are completely soluble in each other (each having a distinct melting point), the melting point of the mixture can be adjusted anywhere between the melting points of the two... | [
"I am not sure which thermometers you are talking about. Maybe if you could include a link, it would be a little easier to explain as there many types of thermometers out there.",
"My best guess, is that you are not talking about actual disposable thermometers, but rather are thinking of the disposable tips that ... | [
"Sorry! The ones I meant specifically are like these single-use ",
"tempa-dot",
" thermometers"
] |
[
"If I had a stationary slinky hanging from a mile up, and let go. Would the bottom stay in place until the top falls down to it?"
] | [
false
] | A really scaled up version of THIS phenomenon for instance. Would it work? | [
"Explanation",
"Longer slinky"
] | [
"Yes, the length of the spring is immaterial."
] | [
"There would be some material considerations. If it can't support its own weight without plastic deformation near the top, then you'll get the same effect but some length near the top will remain extended on its way down."
] |
[
"Photographs growing old."
] | [
false
] | Can someone tell me what the chemical process is that causes photographs to age? I'm looking at some old photographs of mine and they're degrading quite a bit. Google fu-ing produced no relevant information on this process and I'm curious. | [
"Light\nPhotographs are made by the action of light on a specially treated chemical surface (at least they were before digital imagery was invented, but more about that later ...) Little wonder then that even after they are fixed into a stable image, photographs can still be affected by light. Bright light will cau... | [
"That's ok, I hope this answers your question!"
] | [
"Hey, thanks. :)\nSorry for the late reply, I had work. "
] |
[
"Why are most reptiles carnivores?"
] | [
false
] | Why is it that most of the reptile species living today are carnivores? As I understand back in dinosaur days the split was pretty even between carnivorous and plant eating reptiles but now it seems that only a couple reptile species are plant eaters. Is there an evolutionary reason for this? (Can dinosaurs even be con... | [
"First off, dinosaurs are not reptiles. They're their own category closely associated with birds.",
"Dinosaurs can be divided into 2 categories, sauropods and theropods. The sauropods had thick bones and the theropods had hollow bones. There were other differences, such as a hip structure in theropods that was... | [
"Since when are Archosaurs not considered reptiles?"
] | [
"Thank you!"
] |
[
"Why do I always have nightmares when I have a fever?"
] | [
false
] | null | [
"We can't really comment on isolated incidents / personal anecdotes without resorting to speculation."
] | [
"Okm I thought it was sort of common for people to have nightmares when they were sick."
] | [
"Then perhaps a more general question like: do fevers induce nightmares and, if so, why?"
] |
[
"Isn't our leap-year system eventually going to push the seasons out of sync with the months?"
] | [
false
] | If a rotation of the Earth takes 365.24 days, and we count it as 365 days with 366 days every four years, then every fourth year is 1 hour and 36 minutes-ish too long. Eventually, will this cause the seasons to start earlier and then inverse? How long would it take - will we witness it in our lifetimes? Is there anythi... | [
"If the calendar year was exactly 365.25 days, that is what would happen, and it did happen between around 50 BC and 1580 AD, when Pope Gregory instituted a new calendar and skipped twelve days to sync the date back up with the sun. Now we skip three leap years every 400 years to make up for it."
] | [
"The average tropical year is about 365.242181 solar days. Our current calendar has an average of 365.2425 days per year. This is because in addition to having a leap year every four years, we skip it every hundred years except for every 400 years. The calendar is off by about 27.6 seconds. It would take about 3135... | [
"Thanks for your reply, I'm studying History but I had no idea that this had already happened! Very interesting, thanks :)"
] |
[
"How does carbon dating work? How do we know the half life of carbon is \"X\" amount of years accurately? And lastly, how are we so sure what we're using carbon dating on (Fossils, ancient artifacts, etc.) is accurately dated, especially when it gets to be millions or billions of years?"
] | [
false
] | null | [
"There is a known fraction of C-14 in the upper atmosphere thanks to bombardment from cosmic rays. Living plants incorporate this C-14 in with the C-13 and C-12 when photosynthesizing, so they end up with the same fraction of C-14 in their cells. Once they die the amount of C-14 is no longer being replenished but... | [
"this. In addition, I would like to add that there are refinements to the calibration methods such as \"wiggle matching\" where known and well documented fluctuations in the rate of C14 generation and uptake show up as patterns in the otherwise monotonic decay curves. So in addition to just looking at C14 to C12... | [
"To add to Staus's answer, we can calculate the half-life of carbon based on samples of known ages, based on ",
" dating methods, and then seeing how much carbon-14 is left. It follows exponential decay over time."
] |
[
"Are dogs and wolves the same species?"
] | [
false
] | [deleted] | [
"Same species, different subspecies.",
"But it's important to remember that \"species\" is an artificial and arbitrary thing. We assign different living things to different species because that's what we do: we put things in bins. Nature doesn't care one way or the other."
] | [
"Not to be pedantic, but that's only one species concept. It's actually being superseded by modern definitions that account for the fuzzy nature of species relationships. For instance, species of the genus Quercus readily interbreed, yet they are still classified separately. "
] | [
"Totally different. Not even a canid."
] |
[
"Are incest restrictions a social construct or do they exist in other animals?"
] | [
false
] | We've been watching the local deer over the past few years. A year or two ago we had a rare set of triplets born: a buck and two does. They're still hanging out together... along with two new additions. My wife and I have been wondering if the new pair could be the prodigy of the buck and a sister or if another buck wa... | [
"So Arthur Wolf is an anthropologist who has done quite a bit of interesting work on this issue (in humans) and has suggested that there is some biologic basis to incest avoidance, which occurs with early cohabitation.",
"Using populational studies, he examined differences in birth rates in families which co-rais... | [
"Problems associated with incest arise from higher likelihood of recessive alleles coming together within a family line. In humans this can be observed in populations with restricted gene pools such as ",
"polydactyly",
" in the Amish community.",
"However I think you're asking if there is feelings of disgust... | [
"Many animals are observed to avoid incest.",
"https://en.wikipedia.org/wiki/Incest#Animals",
"\n",
"https://en.wikipedia.org/wiki/Animal_sexual_behaviour#Inbreeding_avoidance",
"\n",
"https://en.wikipedia.org/wiki/Inbreeding_avoidance",
"In humans the ",
"Westermarck Effect",
" works to prevent inc... |
[
"what is physically happening to Li when a Li-ion battery is charged under load (while on)?"
] | [
false
] | I understand that the battery does not charge and discharge simultaneously, but rather there's a net charge due to opposite polarization. But does this mean that Li is diffusing slower towards the cathode? | [
"Possibly. The Li diffusion rate is directly proportional to the charging current. The charger circuit may or may not be capable of varying the charging current. It depends on how things are connected, but it's possible to use a power supply that can support charging at the maximum rate regardless of other system l... | [
"With phones and such usually they can vary current up to around 1 amp for the regular \"slow\" charger and around 2 amps for the \"fast\" charger some devices offer (and of course, always 5 volts). The phone draws something like .1 amps by being on in general and around .75 under super heavy load like if it's play... | [
"So, just a clarification, it's not actually always 5 volts anymore. I didn't find a relatively short white paper or anything, but ",
"here's a pretty accessible article for everyone",
" about how quick charge 2.0 works, with support for voltage up to 12v for phone battery charging. Qc 2.0 basically works on ... |
[
"Would it be possible to keep a severed human head alive?"
] | [
false
] | Given unlimited access to any current medical technology, would it be possible to keep a human head alive for any appreciable length of time? If so, would it be possible to keep the head conscious? | [
"Yes. It should be technically possible to keep a severed human head chemically alive and to restore consciousness to it. ",
"We actually discussed a variation of this same question a couple days ago.",
"Though highly controversial, ",
"animal head transplants and severed animal head experiments",
" have be... | [
"Yeah, definitely creepy, and no, they did not reconnect anything other than blood supply. One of the big problems with the head transplant idea is that we have no capability at this stage of attaching the spinal cord from the host body to that of the new head, so any head transplant patient would be rendered a qua... | [
"So, in keeping with this theory, might it not be possible to extract the spinal column along with the head and reattach the nerves accordingly?",
"Is there any promising stem cell research that may allow for the regeneration of damaged spinal columns?"
] |
[
"How does GPS work?"
] | [
false
] | First real post. I was just watching "Through the Wormhole" and Morgan Freeman was talking about GPS being just a system of "time-stamp differences" from satellites. How does this work? What calculations can you do with "timestamps" to determine speed, altitude, etc? Is it calculus in 3d? | [
"Ok, so picture the satellites around the earth. They're constantly sending out a signal that includes a very precise time. When your GPS unit gets that time, it knows (using the speed of light) how far away it is from that satellite, which can be in any direction. So picture a sphere around that satellite. Now... | [
"The math is a system of four equations, given here: ",
"halfway down this page",
".",
"Because it is not a perfect world, and there are many sources of error, you need some error correction, for which you can find the math at ",
"page 18 of this PDF",
".",
"I fear the math is going to be a little harde... | [
"That really makes a lot more sense. The real, actual distance to each of the satellites is calculated in intersecting spheres. What does the math look like? Is there a tool to graph something like this in x,y,z coordinates? "
] |
[
"Why isn't the weather visibly changing all the time on Jupiter like it is on Earth? We could never have a great red spot here because it wouldn't last that long, but on Jupiter a storm can last hundreds of years?"
] | [
false
] | null | [
"Jupiters dynamics are much more rotationally dominated than the Earth. This can be see through the typical Rossby and/or Ekman numbers. ",
" ",
"The Rossby number is the ratio of the inertial to Coriolis forces. That is it is telling us how important rotation is in comparison to the momentum of the fluid. Smal... | [
"These values are usually of most important to dynamo theorists. So the deep interior of Earth is typically (at least for my colleagues) the outer core where rotational dynamics are important. While for Jupiter this is anything less than 0.9R_jupiter (so somewhat everything within the region we believe generates th... | [
"\"for the deep interior we have that Earth is ~10-15 while Jupiter is ~10-18\"",
"What exactly does \"deep interior\" refer to? Earth's mantle? Ocean? Troposphere? What is Jupiter's composition and phase (e.g., rock, supercritical fluids) in its \"deep interior\"?"
] |
[
"What is happening on the molecular level when water puts out a match?"
] | [
false
] | And for that matter, what -is- fire? Is it the fire that emits photons that we see? How? I want an in-depth description of fire because I just realized fire confuses me. A lot. | [
"So first fire is a chemical reaction where oxygen and some \"fuel\" combine to release excess energy as heat and light. But in order to make fire happen you need a little bit of \"starter\" heat to get the molecules up and about to be combined with oxygen. ",
"Water stops this process in two ways. First, the wat... | [
"What is it about water that makes it absorb the heat of the reaction?",
"First off, heat likes to go from warmer to cooler objects. Water is much cooler than any flame. In addition, water is both an extremely good conductor of heat and a good heat sink due to its high heat capacity.",
"Friction",
"What? Wher... | [
"I wish I could upvote more than once. That was really helpful. I understand the other point, that it cuts off the oxygen. But what about water makes it absorb the heat of the reaction? And how does friction introduce the fuel to oxygen? Or does the friction cause the heat energy that starts the reaction in some wa... |
[
"Why are clinical trials for medical research so expensive?"
] | [
false
] | I just wanted to know why there's such large barriers to entry for new drugs and if change is on the horizon - if not, why? | [
"The clinical trial process for getting a drug approved for therapeutic use in the US or Europe requires a lot of data collected in very specific ways requiring the use, eventually of ",
"If you are testing a heart disease drug, there are lots of steps to get the drug from the lab to the market. ",
" The first ... | [
"Putting aside the huge cost of pre-clinical drug development, you have to imagine the army of people that run a clinical trial in addition to the number of patients participating (hundreds to thousands) over the course of several years across several institutions and trial centers.",
"As soon as we have a drug c... | [
"Basically it's because much of the clinical trials are longitudinal studies (long-terms) with a volunteer population in order to ensure that new drugs do not have any long-term side effects that are detrimental to human health. Clinical trials also have to be passed by an ethics committee to prevent abuse."
] |
[
"How do self-driving cars handle directed traffic?"
] | [
false
] | [deleted] | [
"If by directed you are referring to something like a person standing in an intersection signalling cars to go, or an officer directing traffic around an accident, then the short answer is: they can't. It's one of the many hurdles self driving cars still need to overcome, and it's why, to my knowledge, no self-dri... | [
"It's worth pointing out that the proposed change would still require a human being to be able to promptly take control of a vehicle and guide it. This only relaxes the need for them to be physically present; they would be allowed to take control remotely.",
"In a certain sense yes this technically means a human... | [
"Then anyone can go out in a costume with a paddle and direct all the self driving cars into the river!"
] |
[
"If blood contains iron, does it then react on magnetism?"
] | [
false
] | null | [
"The kind of iron in blood is almost completely insensitive to magnetic fields (strictly speaking, it's not ferromagnetic, it is weakly ",
"paramagnetic",
"). People who must work near powerful magnets, who need to remove all ferrous materials, don't need to worry about blood-borne iron being influenced by the ... | [
"Would it be possible to change the frequencies of the magnetic field to target different molecules?",
"The magnetic field is static, it serves to give the different spin states different energies. Which allows you to flip them. That's done with a pulse of radio-frequency radiation. When the spins return to their... | [
"So just to be sure, when you are using MRI for angiography you are still changing the spin of the protons in H2O?",
"Primarily, yes.",
"Would it be possible to change the frequencies of the magnetic field to target different molecules?",
"Most MRI techniques meant to increase the contrast between different k... |
[
"How does a fusion propulsion system or a fusion engine work?"
] | [
false
] | And why is it more efficient than regular energy sources? I know that it is, but I do not know why. Thank you. | [
"Magnets or lasers; no such system has been built yet."
] | [
"The heat from the fusion is used to make gas hot and to power strong electromagnets. The magnets propel the gas out the back, making the ship go forward."
] | [
"Righto, numbers time!",
"We are building a fusion-powered spaceship, with the specification that it must put out as much power as the Space Shuttle+SRBs (13.7 GW) at 1% of the speed of light (the slower we go, the less fuel we collect). Our collection device is entirely perfect, and will collect from an area of ... |
[
"What element has the highest atomic number but also has a \"practicle\" use."
] | [
false
] | I was reading through the periodic table earlier and the elements get more and more "useless" as you go through them. What element has the highest atomic number but is of "practicle" use today? I put practicle in quotes because I don't consider things like neutron sources for nuclear reactors and specialized research ... | [
"Americium 241 (Am-241) is found in most household smoke detectors."
] | [
"Practical",
"FTFY"
] | [
"Pretty much every smoke detector in every home has fraction of a microgram of Americium (Z=95) as an alpha source for the ionization chamber. There was even a ",
"boy scout once",
" who salvaged enough Americium out of a hundred or so surplus smoke detectors to make a neutron gun for a breeder reactor.",
"P... |
[
"Why do muscles hurt more, and for longer, after the first workout in a while than they do after subsequent workouts."
] | [
false
] | I'm a fairly active person: I bike a ton, hit the gym and lift weights, walk, hike etc. But There are certain muscle groups that I neglect (arms, chest) because they aren't used in my other activities. When I go to the gym and do even a light chest workout, say two exercises three sets of ten reps that I can do fairly... | [
"I think the OP is wondering why exactly DOMS is generally more severe after a workout following an extended break than after a workout that is part of a consistent schedule.",
"E.g. OP lifts for the first time in six months, DOMS is very noticeable. OP lifts (at higher weights, more reps) after having been on a... | [
"The simple answer is that enhanced recovery is part of how your muscles adapt to the stresses. That's one of the attributes you develop when you train regularly- enhanced work capacity and recovery time. The different attributes you train will adapt at different rates depending on how you're training. That's wh... | [
"Delayed-onset muscle soreness is caused by small microscopic tears and inflammation in the muscle. DOMS is a common result of physical activity that stresses beyond what it is accustomed to doing.",
"Soreness Remedies:\nIce,\nRest,\nAnti-inflammatory Medication,\nMassage,\nHeat,\nStretch,\nLight aerobic exercise... |
[
"How do you explain the photoelectric effect as a result of the wave function?"
] | [
false
] | So in class, I've only been taught the photoelectric effect as a result of the particle nature of light. However, is there a way to describe it using QM tools like the wavefunction? | [
"Yes, a proper treatment of the photoelectric effect ",
" quantum mechanics.",
"You can treat the problem semi-classically, where you treat the electron quantum-mechanically, but you treat the incident light classically. Although in reality you have a single photon coming in, which is then destroyed in the proc... | [
"I will give a qualitative answer, involving a few technical details. If you want something that will actually allow you to do calculations, you need to follow a textbook. I try to recommend a book, if you like, and if you let me know what your background in math is.",
"Let's start with electrons in crystalline m... | [
"This is a great comment, thanks!"
] |
[
"Does it matter where you adjust the volume of headphones?"
] | [
false
] | For most headphones, there are three ways to change the audio volume: on the headphone itself, on the pc/laptop/tablet and in the program you are running on it. Does the audio quality change depending on where you adjust it? And is there an ideal setting? (Should you put your pc on 100%? 75%? 50%? Or is it all the same... | [
"Generally speaking, you want the highest output input into the amplifier. So, turn up your software first, then the hardware.",
"(Volume that’s turned “down” in software just results in a lower level output, so if that’s not loud enough and you start cranking up a preamp to compensate, you’ll get more noise.)"
] | [
"Software volume control reduces the bit-depth of the signal sent to the DAC, thus reducing the amount of information used to describe the signal, and thereby potentially impacting things like dynamic range.",
"For the best quality audio, if possible, use a hardware volume control post-DAC.",
"To really hear th... | [
"In theory, this is true. In practice, I am not sure it matters. Most headphones are connected to a DAC. Both software controls only affect the power produced by the DAC, so they are largely equivalent unless you are doing some kind of mixing of different audio channels. The inline volume control on most headphones... |
[
"Do battleship gunners have to take the coriolis effect into account when firing?"
] | [
false
] | Somebody mentioned this elsewhere, and it sounded plausible, but I wasn't sure.. Typical 16" deck guns have a max range of about 41km (Just over 25 miles). | [
"The necessity of accounting for the Coriolis force by battleship gunners is discussed in Marion's mechanics book. The relevant paragraph is quoted ",
"here",
":",
"\"During the naval engagement near the Falkland Islands which occurred early in World War I, the British gunners were surprised to see their acc... | [
"From ",
" by John E. Littlewood (1953), pg 51:",
"I heard an account of the battle of the Falkland Islands (early in the 1914 war) from an officer who was there. The German ships were destroyed at extreme range, but it took a long time and salvos were continually falling 100 yards to the left. The effect of th... | [
"Do they mention at what distance this occurred? I'm curious at what point it becomes significant. "
] |
[
"How are packets of data physically assembled, what contains the information and carries it, and what is the physical size of a bit?"
] | [
false
] | I'm so curious about this but I can't find sources that give me all the answers. I hope you guys can tell me. | [
"That depends on where the data is being stored and how it is being transmitted. On hard drives, each bit is a little bubble of magnetically aligned atoms in a metal plate. In RAM, each bit is the charge held by a series of tiny transistors and capacitors. On a flash drive, each bit is a bunch of electrons trapp... | [
"Ultiamtely, the \"size\" of a bit is dependant on ",
" you express it. In today's modern world, computers use, as ",
"/u/icefoxen",
" said, either a magnetic signature, a small hole or bump(as with blu-ray or DVDs), or a specific voltage value (as with processors and RAM). So, the physical size is amazingly... | [
"The term 10-digit, in the way you used it above, is wrong; what you meant to say was a digit, which is a space which can hold up to 10 distinct values (such as Arabic numerals: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.) The term 10-digit generally means ten of these digits.",
"Early computing chose wildly varying number... |
[
"Why was \"Munchausen syndrome\" changed to \"Factitious disorder\"?"
] | [
false
] | null | [
"Likely the same reason that Wegener’s Granulomatosis was changed to Granulomatosis with Polyangiitis, and why Takayasu Arteritis was changed to Giant Cell Arteritis. An eponym is not descriptive of the basic pathology and for this reason is less effective as a descriptor."
] | [
"Of course Friedrich Wegener was a Nazi, so that's the main reason there."
] | [
"A very insightful answer! Thank you."
] |
[
"What is the physical attribute of matter that allows for less or more heat transfer?"
] | [
false
] | Why, physically, do some materials radiate heat very well, and some do not? Is this a physical effect of 'keeping' its vibration? | [
"The property I think you are looking for is either the ",
"thermal conductivity",
" or the closely related ",
"thermal diffusivity",
". The thermal conductivity tells you how quickly heat will flow through a material given a gradient of temperature, while the thermal diffusivity determines how quickly the ... | [
"This. The physical property for this has a proper name, the heat capacity which essentially describes how much heat energy can be put into a material in order to increase its temperature by 1 degree. Since increased temperature is just increased atomic or molecular motion, the more different and unique motions tha... | [
"I believe part of it has to do with the Boltzmann constant, and the other part is the degrees of freedom of the atomic configuration of the matter. Monatoms have only three degrees of freedom, all translational. When you have two different atoms in molecular combination, the two (or more) atoms can also have addit... |
[
"Has Earths rotational speed And axis changed with regards to asteroid strikes?"
] | [
false
] | When the earth experienced major asteroid strikes, did they impact the earth’s: And why or how?! Thanks! | [
"Though it is debated, one popular theory is that the Earth’s moon was formed by a massive impact (perhaps with a Mars-sized body) very early in our planet’s history. The Earth’s moon is unusually large relative to our planet (more than 1% of the mass and a quarter of the diameter) compared to all other planets / m... | [
"Yes. Not an expert by an means. For example it is theorized venus may have been hit hard enough to completely reverse its orbit. Earthquakes here on earth can cause minor (inperseptable) changes in earth's rotation. ",
"Again not an expert "
] | [
"It is speculated that a long time ago a very large asteroid struck Earth and sent it into it’s rotation. This is also said to be the impact that broke a chunk of Earth off and created the moon. Gradually as time goes on, it is said that due to the tides being controlled by the moon, the water “rubbing” against the... |
[
"Are Prime Numbers Endless?"
] | [
false
] | The higher you go, the greater the chance of finding a non prime, right? Multiples of existing primes make new primes rarer. It is possible that there is a limited number of prime numbers? If not, how can we know for certain? | [
"There is no limit to the prime numbers. There are infinitely many of them.",
"There are a couple of things that we know about prime numbers: Firstly, any number bigger than one is divisible by some prime number. Secondly, if N is a number divisible by the prime number p, then the next number divisible by p is N+... | [
"The Mersenne project is currently crowdsourcing CPU power to find the new prime! ",
"Great explanation. "
] | [
"When Newton developed Calculus, it was primarily for the motion of planets. Nothing useful/every day. 300 years later phones, rockets, cars, etc. wouldn't exist without it. It may not have amazing, flashy uses now but it doesn't mean it can't in the future. ",
"Edit: also the hunt for large prime numbers may rev... |
[
"Are the molecules that comprise air effectively transparent, or would we visually perceive things differently if the air was a removed from our atmosphere?"
] | [
false
] | What the title says. General perception has me interested lately. | [
"Uhh... the distance between molecules in a gas at STP is measured on the order of nanometers, so it's not the distance that causes transparency.",
"And you definitely would notice that we have no atmosphere, at least in the day: there wouldn't be anything to scatter light and give the sky color. You would be loo... | [
"The elements in air don't absorbed strongly in the visible. Frozen or liquid nitrogen is transparent."
] | [
"The molecules themselves aren't transparent, but there's so much space between them in their gaseous state that it's effectively transparent. So no, we wouldn't notice any visual difference if the air was gone. \nOf course, we'd be too busy suffocating to notice anyway. "
] |
[
"Why is the eastern United States so different in climate compared to to the western United States?"
] | [
false
] | I'm talking little things like why does a town like Millers, Nevada have such a different climate than Charlotte NC (both roughly 300 miles from their closest ocean.) One is in a dry high desert while the other is a relatively hot and wooded region. There isn't a big north vs south difference yet they are so different ... | [
"Coriolis motion in the Northern Hemisphere goes clockwise. That means air and water are circulating clockwise. So the East Coast has warm air and water moving up from the south, the West Coast has air and water moving down from the north.",
"No, this is incorrect.",
"First, clockwise motion over the US would d... | [
"One of the reasons is that the ocean water by California is much colder than the Gulf of Mexico and Atlantic Ocean (currents push the water from near Alaska all way down to California). Colder water evaporates less and cools the air. Cooler air can hold less moisture as well. ",
"Also, mountains and hills filter... | [
"It can't just be the mountains, though. San Francisco itself, right on the coast, is much drier than Charlotte (~23\" of rain vs. ~42\" in Charlotte), and that precipitation is concentrated heavily in the winter months. Growing up the Bay Area, even in the mountains, it basically never rained during the summer, ... |
[
"Is uranium ore radioactive?"
] | [
false
] | I know it is but I am more interested in level of that radiation. Is it any more significant than backround radiation? | [
"It is definitely more significant than background radiation but it isn't very radioactive.",
"Uranium ore contains small amounts of uranium, mostly U238 but a tiny amount U235 too. Both these isotopoes are radioactive and emit both gamma rays and alpha particles, these can cause damage to humans.",
"However bo... | [
"Thank you"
] | [
"Uranium ore contains small amounts of uranium",
"That ",
" depends on the uranium deposit.",
"Yes, there are very large low-grade uranium deposits such as Rössing, with grades around 0.02%, and the sandstone-hosted deposits of the American SW as well. Say Roll-front U in sandstone and disseminated U in migma... |
[
"What is the \"ceiling\" for perceivable video resolution?"
] | [
false
] | So, with the increasing quality of video resolution, the number (720p, 1080p) being amount of pixels and pixel depth (from what I understand, I am also not very tech informed/savy. If I am misinformed, I would also love a bit of ELI5); what is the maximum resolution that can be achieved where any further progress would... | [
"Apple's marketing team makes the claim that the \"Retina Display\" for their new iPad has such a high pixel density that further improvements wouldn't result in a higher perceived resolution (at normal viewing distances). ",
"However: \"For raster graphics, Apple Inc asserts that a display of approximately 300 p... | [
"Because it's a product review, not anecdotal evidence."
] | [
"As it turns out there's some physical limitations to the ability of an optical system (your eye) to resolve detail, so lets take an extreme example and see how many pixels it would take.",
"So lets say you've got perfect vision and really big pupils. Lets also assume you're watching a relatively dim screen in a... |
[
"If you put magnets in water, what kind of charge does the water take on?"
] | [
false
] | [deleted] | [
"Without commenting on the effect of ions on your body (because I'm a physicist), magnets do not affect ions in an appreciable way. Placing magnets around you has no effect on whether you're surrounded by ions or not.",
"While I'm not a biologist, I can say with certainty that any magnetic product that promises m... | [
"If there was a biological effect with consumer magnets an MRI would be absolutely catastrophic."
] | [
"Veritasium did a really good video on the whole negative ions thing. In short, yeah, you might as well use magic crystals—there's no evidence other than flawed studies to say negative/positive ions actually do ",
"."
] |
[
"Why is there a difference in composition of solar system bodies?"
] | [
false
] | The sun is almost entirely hydrogen and helium by mass, with oxygen, carbon and other elements in small quantities. Compare that to the earth for instance, with 75% of its mass coming from oxygen and silicon. My question is, why is there such a difference between composition? As far as I'm aware, the current model for ... | [
"Let's start at the very beginning and work our way through!",
"Our solar system was originally a big ball of gas and dust. About 98% of the mass of this cloud is Hydrogen, Helium, and a little bit of Lithium. These are the elements that were formed right after the big bang. The other two percent are the heavier ... | [
"One big point that seems off in here is that the solar wind from the sun would've blown the light hydrogen and helium out to the outer solar system, so it's not a question of melting point so much as how light the atoms and molecules are."
] | [
"That certainly plays a part in it, but it plays a larger role in the composition of atmospheres I believe. ",
"Before the cloud collapses there are already a bunch of dust grains formed, the majority of which appear to be covered in ices. ",
"Let's say the solar wind exerts a constant force on everything at a ... |
[
"if you can see the sun and the moon at the same time, what happens on the other side of the world?"
] | [
false
] | null | [
"So, despite the artistic clichés, the Moon is up during the day just as much as it's up during the night. You can have the moon up all day, or you could have the moon underground all night.",
"In this situation, someone on the opposite side of the world would just have a moonless night, which is common and norma... | [
"You can't get a sunset and moonrise in a single photo because they're always almost exactly on opposite sides of the sky. Almost no camera lenses capture enough field of view to photograph this in a single photo, and certainly no commonly available ones.",
"You could capture them in a panorama sweep, which stitc... | [
"You can have the moon up all day, or you could have the moon underground all night.",
"So....hollow Earth confirmed?"
] |
[
"How are memories stored and retrieved?"
] | [
false
] | Are they stored as discreet units? As in, one memory is contained in one neuron or protein and related memories are located near that unit? Or am I completely off base in my assumptions? I have a basic understanding of A&P so I can handle technical jargon if you need to use it. Thank you. Edit: Thanks for the answers.... | [
"Are they stored as discreet units?",
"We think that memories are created by upregulating synapses between neurons in the brain. In this sense, it is not a single protein or a single cell that holds a memory per se, it is the sum of a number of synaptical changes throughout the brain. In other words, your brain... | [
"This is your quick and simple answer. Just wanted to add that downregulating synapses (LTD) can be just as important for learning and memory. ",
"But as craig says, memories aren't really discrete things (i.e. proteins or neurons), but more a result of highly tuned, specific patterns of neuronal activation. Long... | [
"I'm very interested in reading more about this. Could you direct me to some literature so I can continue exploring, please?"
] |
[
"Do we actually know what colour dinosaurs were if we only have the bones?"
] | [
false
] | My friend recently asked me if humans actually know what colour dinosaurs skin was considering we only have the bones. I've been thinking about it as well and am curious weather or not the colors were just picked at random. How do humans know what colour dinosaurs were? | [
"You're reasoning from analogy, not from empirical evidence. Further, your description of modern-day animals isn't really even that accurate (",
"example 1",
", ",
"example 2",
")"
] | [
"You're reasoning from analogy, not from empirical evidence. Further, your description of modern-day animals isn't really even that accurate (",
"example 1",
", ",
"example 2",
")"
] | [
"I took a paleo course decades ago taught by Peter Dodson at the Academy of Natural Sciences and he was visibly excited about this possibility. He said we had no idea, they could have been all kinds of colors, not just a lumbering gray. That was ",
" feather evidence was discovered and now paleontologists have so... |
[
"How does a flame always burn upwards?"
] | [
false
] | null | [
"A flame is generally a region of heated gas (the specifics depend on what exactly is burning). Just from looking at something like the ideal gas law, PV=nRT, we see that the density n/V drops as the temperature T grows. So our region of heat gas is going to be much less dense than the surrounding colder air, so th... | [
"candle flames are spherical in space.... JUST LIKE A STAR. this just blew my mind."
] | [
"yep. try throwing a water bottle up in the air - the bubble won't stay at the top, because buoyant forces aren't at play in free-fall.",
"to ramble a bit, it's a common misconception that they're in zero gravity - if memory serves me right, it's about 9.5 compared to 9.81 down here. they're just in free fall. th... |
[
"Do our eyes Focus the same way on distant objects in real life as they would on perceived distant objects on a TV screen/ VR /phone/ PC?"
] | [
false
] | null | [
"No. For a TV screen, your eyes are focusing on the plane of the TV. No matter what is shown on thr TV, your always are always focusing at the same distance."
] | [
"I feel like when your eye perceives something, regardless of actual distance, your eyes focus differently. I mean I don't know for sure. I was hoping someone would unleash some science. Those 4k hdr tvs are packed with tiny detail, in some cases they look identical to looking out of a windows. LG has these \"wallp... | [
"Your eyes focus the same on every point on a TV screen. ",
"In VR, you are still keeping a fixed focal distance, but there is a lens in there in front of the screen which makes the focal point farther than just the few cm that the screen is in front of your eye. See the video ",
"here",
" "
] |
[
"AskScience AMA Series: We are neuroscience & neurotechnology researchers at Harvard Medical School with a mission to communicate science to general audiences. Ask us anything!"
] | [
false
] | [deleted] | [
"Thanks for finding time to do an AMA series! I remember reading an article on the advancement of neurotechnology in the area of dyslexia. What is the current status of this progress and if this is successful, how much longer until the same technology research can be used to start looking into cures for blindness ... | [
"Thanks for doing this! \nI saw that ",
"Brazil had changed their microcephaly cut off from 33 cm to 32 cm",
", changing it from -2 to -3 SDs. The reasoning behind it seems to be that no structural anomalies were found in the brains of infants with head sizes between -2 and -3 SDs. \nHow accurately can one pred... | [
"What is your best advice to scientists wanting to communicate their work to general audiences?"
] |
[
"Do CPUs at GHz frequencies emit detectable amounts of microwave radiation?"
] | [
false
] | null | [
"Very detectable. Large telescopes that work in the low frequency range like the GBT often don't allow ANY computing devices within a certain radius. Even the control room has buried wires that control the instrument from a good bit away now.",
"We run some high end scopes in our lab as well and they are regula... | [
"I guess detectable is a very relative term."
] | [
"The radiation is insignificant.\nBut the laptop produces heat anyway.This heat can lead to reduced sperm count if the laptop is placed near the scrotum.\n",
"Snopes article with more explanation and news sources"
] |
[
"KOH + H2O2 ??? (Leaking waste containers)"
] | [
false
] | null | [
"Got it."
] | [
"These questions cross over to safety advice, which isn't what ",
"/r/askscience",
" is about.",
"If you have any safety concerns you should be contacting your occupational health and safety department, instead of asking someone online for advice."
] | [
"Safety questions shouldn't be released."
] |
[
"At normal temperature and pressure, is there a gas that is dense enough to limit a person's movement?"
] | [
false
] | null | [
"Using the ideal gas law, we can figure out which gas would be the densest:",
"P = ρ (R/M) T",
"...where P = pressure, ρ = density, R = the universal gas constant, M = molar mass, and T = temperature. Rearranging to solve for density:",
"ρ = (PM)/(RT)",
"Since you've specified STP, and R is a constant, the ... | [
"By normal temp and pressure, do you mean at STP as a temperature of 273.15 K and an absolute pressure of 100 kPa?"
] | [
"at STP."
] |
[
"Is hypertension independent of stress?"
] | [
false
] | I came across a line in Davidson's textbook of medicine which said there isn't sufficient evidence to link the two. What say? | [
"Chronic stress is one of the causes of hypertension (HTN). Stress elevates the level of catecholamines, which will increase peripheral resistance, heart rate and venous tone - all in turn will increase blood pressure (BP). Another \"stress hormone\" is cortisol that also increases BP. "
] | [
"Acute stress can acutely raise blood pressure, but it will eventually return to normal levels. Lots of environmental factors can modulate blood pressure, but assuming an individual is healthy various CV control systems will operate to return blood pressure to normal levels."
] | [
"It is hard to talk about what the textbook is saying without reading it...but if I had to make an assumption on their statement, it would be this.",
"Hypertension tends to have a \"lifelong\" diagnoses associated with it. Would be associated to a heart condition, vascular condition, kidney, etc... Temporarily ha... |
[
"Why do I get itchy with red bumps whenever it starts to get warm?"
] | [
false
] | Recently I've noticed that anytime my body temperature rises (exercise, hot weather etc.) I get really itchy everywhere. I get a lot of small red bumps everywhere too. It's only happened for the past year or so and has never happened to me. Is there some sort of treatment? | [
"Sounds like ",
"cholinergic urticaria",
". I've had it since I was a kid, and none of the treatments have worked. What does work is regulating my temperature, especially at night. If I get too cold at night, then the urticaria is easily aggravated by heat. If I stay warm at night, then it's much better. Regula... | [
"Well that sounds difficult to live with.\nDoes the itching go away after you start exercising more often?"
] | [
"Yes, it did for me. Everyone is different, though, and some people have better luck with meds. "
] |
[
"How does hyperbaric oxygen therapy help heal traumatic brain injuries?"
] | [
false
] | It's obviously not a science article. This is the first I have heard of this, and other than the obvious increased oxygen saturation, I'm not really sure how hyperbaric oxygen therapy could help heal brain damage? | [
"Ok, this post might get a little long, but bear with me.",
"First, when discussing hyperbaric oxygen therapy, it is important to remember that at the concentrations of oxygen present, the result is more akin to a medication (with a wide array of effects) than it seems on the surface. ",
"To put it in perspecti... | [
"Interesting, thank you! Is there a good review of the literature written by someone yet or a citation list that anyone has put together?"
] | [
"There's a book called Hyperbaric Oxygen for Neurological Disorders by Dr. Zhang that would be a good start. There is also some work by Dr. Paul Harch (who is a big proponent), but I'd take it with a healthy dose of skepticism. There are also a couple overviews that have been written for the NIH and UHMS (Undersea ... |
[
"Domesticated animals of varying species seem to have little problem bonding, hanging out, forming friendships, etc. Does this occur between different species of animal in the wild? Do herds exist that consist of multiple species of animal, like lions with cheetahs, or antelope with water-buffalo?"
] | [
false
] | null | [
"Indeed they do form! Mutualism of this kind is more common than we had once thought. Some examples which I remember from uni are as follows. Aphid-ant co-predation in which the ants follow aphids, which seek the ovipositions of honeydew plants, and thereby find food resources. Interspecies avian flocks are well-do... | [
"I should note, though, that species have more to be gained from heterospecific predation defense than from sharing a food community. The fitness effect of being eaten is that you will never reproduce again and any dependents will likely die, so it is worth taking some small sacrifice by working with other species.... | [
"Domesticated animals of varying species seem to have little problem bonding, hanging out, forming friendships, etc",
"This is not a coincidence, either. In fact, to a great extent, it's the other way around. \"Animals that have little problem hanging around other species are often domesticated as a result\". ... |
[
"Do rainbows only exist in the visible spectrum?"
] | [
false
] | Is it possible to have rainbows of other parts of the EMS, for instance in shades of X-ray, or perhaps radio? If so, are there any naturally occurring instances of this? | [
"Rainbows, as we experience them, are the result of light scattering from the inside of water droplets, like ",
"this",
". If the light is available, any light that will interact correctly with the water droplet should form a rainbow. X-rays and radio waves, with their very high and low frequencies (respectivel... | [
"Rainbows are ",
"caused by refraction of light through rain drops",
". The refraction occurs for all wavelengths of light, not just the visible spectrum. So ",
" rainbow includes light outside the visible spectrum. For example check out these two pictures of the same rainbow: ",
"this one in the normal vis... | [
"Rainbows occur because of refraction. All waves can be refracted (refraction is one of the main defining characteristics of wave-like behaviour), including all electromagnetic waves.",
"Rainbows occur because water droplets in the sky refract light (and probably some UV and IR radiation) like a prism. X-rays ca... |
[
"If two people, from completely different countries, both had the same hereditary trait..."
] | [
false
] | Does this mean somewhere up the family tree they're both related? I know very little about genetics, but the post about on the front-page just got me wondering. | [
"Somewhere",
" up the family tree, ",
" related."
] | [
"Hereditary traits are the manifestation of differences in protein expression or function. These can arise through mutation, but not necessarily mutations in the same place. A disease that is caused by a non-functional protein (such as Kindler syndrome, an inheritable skin disorder causing severe blistering, among ... | [
"I don't know how likely it is, but it's definitely possible for the mutation causing that reflex to have occurred in two separate instances."
] |
[
"Why do we have to \"fall\" asleep? Why can't we just decide to be asleep?"
] | [
false
] | null | [
"Sleeping literally changes our very physiology. Our core body temperature drops which allows certain proteins to work differently than they do during our \"waking temp,\" as a broad example. It's not something we'd want easy control over. ",
"Most importantly the process of getting sleepy is highly regulated by ... | [
"Sleep hormones are high, minimal movement, your body is starting the sleep process on the couch. Then you decide to get up, and a big red button is pressed that fires some cortisol for alertness and slows/stops the process. You’re waking yourself up, and thus the process restarts. "
] | [
"What is happening late at night, when you can barely keep your eyes open and keep nodding off on the sofa. So you go to bed and are suddenly not tired and it takes about an hour to get to sleep?"
] |
[
"Light Engineers - Can you explain to me IESNA Light Distribution (Type I, IIm, etc) ?"
] | [
false
] | I own an LED company and we are now working on incorporating LED street lighting into our product line. We no longer have an Engineer on staff and I come to you all for help! We have sourced an amazing product for LED street lighting and I need help understanding the IES distribution. S1M111 (IESNA Type I Medium); S1M1... | [
"r/askengineers",
" will know this ... would you consider donating to a charity chosen by the answerer, bearing in mind this is commerical application?",
"edit: url formatting"
] | [
"Well, there are different distributions for a reasons, different roadways, etc. ",
"This document explains the different types the best: ",
"http://www.agi32.com/kb/index.php?article=77",
" "
] | [
"Thanks!"
] |
[
"What's going on with Nickel-63's beta radiation?"
] | [
false
] | One of my jobs is to survey potentially radioactive packages to ensure they conform to DoT requirements and are safe for mailing, and in our refresher training today Nickel-63 got brought up, specifically because it's such a low energy beta emitter that instruments have a hard time detecting it. I was curious why we wo... | [
"I'm not a health physics expert, but I can point out that its decay energy is several times higher than that of tritium (67 keV vs 19 keV), and ",
"tritium is dangerous if ingested",
"."
] | [
"In response to the original posted question: \nYou're correct in assuming that very little Brems Xrays will be produced. That does not mean that none will be produced. The majority of the particle interactions will be dominated by the collisional stopping power - which is still able to directly ionize materials. "... | [
"I love tritium, because if an instrument with a tritium-based dial ever breaks there's no awkward hazmat disposal. After sleeping on it I think the question might be more appropriately rephrased as \"Is there any danger from a surface contaminated with Nickel-63's beta radiation?\" The hazard distance in air is a ... |
[
"[Engineering] Why does spacex prefer to land on the ground instead of on a barge at sea?"
] | [
false
] | Today Spacex landed a rocket again, and it went back to the landing zone in Florida. But why do they do this instead of landing on a barge? Wouldn't it save on fuel and therefor costs? | [
"SpaceX does not prefer sea landings. They choose to land on land whenever possible. ",
"To make it back to the launch site takes quite a bit of extra fuel; they need to do a boostback burn that cancels out all the forward momentum and sends them back the opposite direction. ",
"If they are launching a Dragon t... | [
"There's a section on the FAQ in ",
"/r/SpaceX",
" about this question: ",
"https://www.reddit.com/r/spacex/wiki/faq/reusability#wiki_why_does_spacex_sometimes_land_on_the_asds_when_they_could_land_back_at_the_pad.3F",
" ",
"The part that is not addressed is yes, it would save fuel and therefore cost, ho... | [
"Two things to consider...",
"The cost of doing a barge landing is the cost to tow the barge a few hundred miles out to sea and back, plus the cost of sending a recovery ship out there. There is also the cost of not having that booster available for the time it takes to get it back, and there are theories (not co... |
[
"What kind of signals do you think we'd be able to detect from a Type II or Type III civilization living in the nearby universe?"
] | [
false
] | null | [
"A Dyson sphere would have the luminosity of a star but an incorrect spectral profile."
] | [
"You have to dump that waste heat eventually..."
] | [
"No, there ",
" be waste heat. You cannot turn all of the energy coming out of the star into useful work - this is denied by the second law of thermodynamics. Some (large) percentage ",
" be waste heat. And even the energy you do capture, you eventually have to radiate off - you have finite capacity to store en... |
[
"How much energy does intense thinking use?"
] | [
false
] | Does thinking hard on something burn a significant amount of energy, relative to other sedentary activities, such as sleeping or watching television? | [
"Your brain, in general, accounts for about 20 per cent of your total energy requirements. That's an average of 400-500 calories a day, but it varies according to how hard your brain is working. Under deep anaesthesia, your brain still needs about 150 calories a day. But experiments with rats have shown that just m... | [
"Thanks for the quick reply. That's interesting."
] | [
"While not necessarily meditation, when I'm cutting the fastest laps I can on the xbox formula 1 game, I forget how hard i am focusing and for how long until I notice myself getting quite warm and even sweating from time to time........"
] |
[
"Underground space terrarium question."
] | [
false
] | If you were to drill a hole on mars, dig out a cavity, cover the hole with an airlock, and put air inside the cavity, would it stay there? Or is the ground of mars too porous? If it was possible, how deep would you have to drill? Also, could you use the blue and red LEDs to host an underground terrarium? Would it be ea... | [
"Keep in mind that\na) Mars is a whole planet, with a huge variety of rock and soil types of varying porosity.\nb) If the walls have pores which let out air, you could seal them up with some sort of paint equivalent. This is more-or-less how they keep radon out of basements."
] | [
"I actually did a NASA internship last year where I planned something like this. There are pre-existing lava tubes on the surface that you would probably want to use, instead of digging new holes. Look up the Seven Sisters skylights, we've got pictures from orbit of cave-ins along lava tubes running down Arsia Mo... | [
"The surface area of Mars is roughly equivalent to the land area of Earth. :-)",
"- ",
"http://en.wikipedia.org/wiki/Mars",
" - ",
"- ",
"http://en.wikipedia.org/wiki/Earth",
" -"
] |
[
"How long would a human from 10,000 years ago survive with todays medicine?"
] | [
false
] | I guess it's pretty self explanatory... Is life expectancy genetic? | [
"Infant mortality rates (which were far higher in the past) really skew average life expectancy rates. ",
"Here",
" are some ",
"pages",
" to look at for the curious, but to paraphrase—European infant mortality rates went from 73 per 1,000 births to 10 per 1,000 in a period of 50 years. At the same time, li... | [
"Today's medicine can only keep a person alive for so long, One thing that you can't account for is there level of actual immunity to certain diseases or illnesses that we have today. ",
"Take for example when Europe started to colonize parts of america and there was great disease throughout the natives as they h... | [
"But those differences were not genetic in any way. This paper has some excellent data on survivorship among hunter-gatherers and small scale hortaculturists (Roman survival would probably be a bit worse) ",
"http://www.anth.ucsb.edu/faculty/gurven/papers/pdrdraft04182006.pdf",
"Basically the modal (or typical... |
[
"AskScience AMA Series: We are Dr. Karen Cranston and Dr. Stephen Smith, computational and evolutionary biologists at Duke and U Michigan and other members of the Open Tree of Life team, here to answer questions about the Tree of Life, AMA!"
] | [
false
] | Hi reddit! We have just released a draft of the tree of life ( ) that includes 2.3 million named and extant species. This is the first attempt to automatically combine published evolutionary trees (phylogenies) into a comprehensive tree of life. This publication is only the beginning, and we will update the tree of lif... | [
"What did you discover at the root of the tree i.e. is there a point of origin? \nHow long did it take you to compile this?\nCan this data be used to predict or see evolutionary trends?\nHow is the data stored and how big is it? "
] | [
"We didn't really discover the root in this particular analysis. The root of the tree of life is something that has been determined from other analyses using genomic data and characters. Our analyses use these previously published hypotheses to inform the construction of the larger draft tree of life.",
"As for h... | [
"Hi, thanks for your interest in the project!",
"This is more of a summary and synthesis of previous estimates. So, there are not a lot of novel groupings. In my opinion, the significance of the project comes more from the fact that we've built the infrastructure to maintain a current summary of the entire tree a... |
[
"How does language (grammar, linguistic structure, etc.) affect our personal thinking processes and would that affect tendencies in culture?"
] | [
false
] | null | [
"I'm a linguist (BA, some research). First of all: this is a controversial topic. Don't believe anyone who tells you language certainly does or certainly doesn't affect our culture and thought. To give you a bit of background, the first modern work on this was the Sapir-Whorf hypothesis:",
"http://en.wikipedia.or... | [
"I don't know how this subreddit reacts to this kind of response, but I have nothing really to say other than you should read books by ",
"Steven Pinker",
". He write extensively on exactly what you are wondering about in several of his books, such as The Language Instinct (1994), How the Mind Works (1997), Wor... | [
"Showing that spatial representations are influenced by language is only one aspect of general cognition. The topic is controversial because it is a wide-ranging and very open-ended statement. Somebody with blanket acceptance of \"linguistic relativism\" could come to all kinds of crazy conclusions unless each spec... |
[
"If wave function collapse occurs when the wave function is observed or interacts with the 'external world,' how can we know it was in a superpositioned state before observation?"
] | [
false
] | null | [
"Your feeling is correct that a single measurement does not justify the use of superposition. It is the interference effects observed in large collections of measurement results (within a single quantum experiment) that require us to say each particle travelled along multiple superposed trajectories."
] | [
"To add to what other's have written what you're asking is essentially asking what is the difference between a pure state and mixed state in QM. ",
"A pure state is an object with probability amplitudes in different basis states. The quintessential example is an electron whose spin in a given value in one directi... | [
"Superposition itself is nothing unusual. If you pluck a guitar string, the resulting oscillation is a superposition of sine waves."
] |
[
"In multiverse theories is time comparable between universes? If so can there be \"earlier\" universes than ours?"
] | [
false
] | This is very much a layman question. Follow up: if true does this mean "time" didnt start with the big bang? if false does this mean multiverses exist outside a natural "time"? | [
"That doesn't really make any sense.",
"Think of space-time.",
"If you have an entirely different universe does it make sense to ask whether or not that universe is to the left or right or up or down relative to our universe? It's completely separated from our dimensions, it's not anywhere relative to our dimen... | [
"In multiverse theories is time comparable between universes?",
"The specifics depend on which multiverse theory you're looking at, but it can be. ",
"Keep in mind that the specific of comparing time across locations even in the same universe can be tricky enough, because of relativity - there isn't a single a... | [
"Actually it does make sense. There is nothing philosophically problematic with the idea that you have different universes where time happens to be synchronized, in some sense. All you need to do to get this is to ensure that the difference universes can't interact in any substantially normally way. Like, for insta... |
[
"Why do some birds (owls, eagles) have feathers on their legs while others (seagulls, corvids) don't?"
] | [
false
] | Is it to do with flight? Warmth? Other? Does this factor into taxonomy? | [
"From what I recall most of the birds that don't have feathered legs are scavenger/carrion feeding birds. They often stand in filth and rotten bodies for quite some time, and by not having feathers it makes it easier for all that stuff to be cleaned off and not cause infections"
] | [
"Also: swimming/wading birds generally don't. (Seagulls/ducks/egrets/flamingos/herons/geese...)",
"Function plays a big role here."
] | [
"You mention that eagles have feathers on their legs which, while mostly true, isn’t true in all cases. ",
"An interesting exception is the brown snake eagle, native to parts of Africa. It has completely bare legs, making it pretty unique and easy to identify. They do in place of feathers, however, have thick sca... |
[
"Common house flies seem to be attracted to landing on living people/animals, are they able to gain any nutrients or any thing useful by doing this?"
] | [
false
] | null | [
"http://www.mnn.com/earth-matters/animals/questions/why-do-flies-fly-toward-and-land-on-people"
] | [
"thanks"
] | [
"I cannot answer for flies, however I can tell you something about mosquitos, they get attrafted to CO2 being exhaled, thats how they find a prey, specifically us. I am guessing that since all of the animals exhale CO2 , they are potential food source for them... "
] |
[
"Are whales, dolphins and other marine life affected by massive ocean storms? Is it hard for a dolphin to get to the surface for air when waves are 20ft high and the ocean is churning?"
] | [
false
] | [deleted] | [
"Sharks will go deep during a hurricane. Low pressure in the atmosphere above the water will reduce pressure under water, fooling them into thinking they are swimming shallower than they are. ",
"http://www.in-fisherman.com/2011/07/12/weather-pattern-pike/",
"http://www.pbo.co.uk/news/405790/new-research-indica... | [
"http://blogs.scientificamerican.com/thoughtful-animal/2012/08/31/what-do-hurricanes-mean-for-dolphins/"
] | [
"So, basically, it ends up being very beneficial because humans don't bother them and consume their food as much? Interesting."
] |
[
"How are we able to distinguish between two sounds that are the same pitch but come from different instruments?"
] | [
false
] | For example how come a violin playing a note with a frequency of 196Hz sounds different than a trumpet playing at 196Hz? | [
"The differences you're noticing in the sound is generally called the \"timbre\" (French for \"stamp\") of the instrument. Physically, what's happening is that a single note is the fundamental frequency of the pressure wave being generated, which is the same for different instruments, but each instrument imprints a... | [
"No (or almost no) instrument creates a pure pitch. They are all embedded with various harmonics. Only a pure sine wave is a pure pitch. You don't get a pure sine wave from striking a guitar string, or a piano key or blowing into a horn."
] | [
"So what you hear is hardly ever a single, perfect note",
"This is a \"perfect note\"",
" (a sine wave). It can also generate square waves and a bit more and you can hear the difference."
] |
[
"Does an ice cube excert more gravitational pull than the same amount of floating water?"
] | [
false
] | [deleted] | [
"What matters is how much mass there is. A 1 gram block of ice has the same mass as 1 gram of water, and therefore they have the same gravitational properties. ",
"You're probably thinking about neutron stars, in that case it's VERY densely packed. The density of a neutron star is akin to compacting a herd of 50-... | [
"The density (how close together they are) has little to nothing to do with the gravitational pull. If you took a half kilogram block of ice, it would exert the same pull as a half kilogram of water, because it's only mass that affects gravity. ",
"If however you took a bucket full of one big ice block and compar... | [
"The density (how close together they are) has little to nothing to do with the gravitational pull.",
"That assumes the objects can be treated as point masses, which isn't exactly true when they're close together. For objects that are close together, the distance between the volume units making up the objects dif... |
[
"What is the current state of research into the origin of the first life on Earth? Are new experiments on abiogenesis being conducted?"
] | [
false
] | I have read about panspermia/transpermia and abiogenesis and the Miller–Urey experiment from 1953. However, none of these provide a satisfying answer to the question of how/when the first life forms came to populate our planet. Has any new evidence surfaced in recent years? Is there an active branch of scientists worki... | [
"Wether life started on Earth or came on asteroids remains unproven.",
"Newer evidence, however, has shown that some organisms can survive all the conditions found in outer space (extreme temperature changes, UV, vacuum, atomic oxygen, energetic particle radiation). This was an ESA experiment on the ISS.",
"htt... | [
"I heard about that, that was very recently. I just somehow hope that life arose on earth first so that we can figure out how that happened. "
] | [
"That's a very valid point. Unfortunately we don't have enough evidence yet.",
"If Rosetta finds organic molecules in the comet then it will be a meaningful discovery. Stay tuned for the news."
] |
[
"Is it possible to generate what we picture in our brain based on purely by the recorded brain signals?"
] | [
false
] | null | [
"edit: I have completely misread your question, my apologies. Well, there are people working on reconstructing what we actually see anyway, which I think is pretty neat.",
"It looks like there ",
" people working on this, although imagined image reconstruction is not very accurate: ",
"https://journals.plos.o... | [
"The short answer is not with our current technology/knowledge.",
"for starters, our brains are far more complex than the best artificial neural network that exists. neural networks have a LONG way to go to properly simulate our brain.",
"Even if we isolate the problem down to one neural pathway, we still lack ... | [
"The problem is in tracking the neural activity. Do you have a way to measure the activity of every individual neuron in the brain? There's 100 billion of them, and you can't measure the signaling of indiviual neurons without invasive procedures. There's no way to collect that data. Also, you would have to have so... |
[
"Do your fingerprints resemble your parents' fingerprints?"
] | [
false
] | Are fingerprints a hereditary trait? Do they (even vaguely) resemble parental fingerprints? | [
"Fingerprints are formed due to environmental factors. Differential pressure in the growing volar pads during fetal development leads to the patterns you see. This is the reason even identical twins would have different fingerprints."
] | [
"Why are there only a couple of types of fingerprint styles (arch, loop, whorl)? Why isn't it more random?"
] | [
"If a fetus has, I don't know, lack of nutritional or biological needs in the womb, can that be 'detected' by looking at fingerprints?"
] |
[
"Do we use the same parts of the brain to learn programming as we do for learning to write in a new language?"
] | [
false
] | Or do we use the same parts of our brain when we write and when we code? I was writing a program the other day and this question popped in my head.... | [
"Good question. I'd like to add to it: if programming languages do use similar brain pathways, does a programmer get similar health benefits as a multilingual? E.g. ",
"http://en.wikipedia.org/wiki/Multilingualism#Health_Benefits_of_Multilingualism_and_Bilingualism"
] | [
"This is an interesting question. The answer is mostly yes. You will undoubtably use several regions of your brain dedicated to language processing, including ",
"Broca's",
" and ",
"Wernicke's",
" area. Broca's area allows you to convey language-related information while Wernicke's allows you to comprehend... | [
"That's a good point, however as researchers pointed out this was probably \"due to working memory problems\". Writing or typing things out helps to circumvent working/short-term memory deficits. As I see it (I am a computational neuroscientist, and do a fair amount of programming myself), there is several parallel... |
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