title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"How much does a 15 minute 110°F shower raise your core body temperature (if at all)?"
] | [
false
] | null | [
"Your body temperature would rise a tiny amount but it wouldn't be much, the body is good at regulating temperature and many vital bodily functions don't work well if the body's temperature is far from its normal temperature. As for the magnitude of the change, there are too many variables involved and I'm too lazy... | [
"The water that is on the skin evaporates cooling the body acting as sweat. This is in a shower. If submerged this cannot happen causing body temperature to raise faster. This is why you should not be in a hot tub for a prolonged period of time."
] | [
"Isn't the primary mode of temperature regulation perspiration (at least on the cooling end the spectrum)? How does being in an essentially 100% humidity environment effect said cooling?"
] |
[
"Imagine there is an asteroid the mass of a fridge floating in space and isn't gravitationally affected by any other object. Could this asteroid have its own tiny satellite?"
] | [
false
] | null | [
"Yes, it could."
] | [
"Well, OP asked \"the mass of a fridge\", not necessarily the same shape. Anyway you're right that with a low mass it cannot be expected to be spherical. But wouldn't this effect become negligible at a certain distance? After all ",
"243 Ida",
" does not look spherical at all and it has a satellite."
] | [
"I wonder if the asphericity would destabilize the orbit. e.g. the monopole is cancelled by orbital velocity, but then the not-insignificant quadrupole tanks it."
] |
[
"If photons can't escape from a black hole, how can a charged black hole repel or attract electrons outside?"
] | [
false
] | Wasn't it photons that give electromagnetism? | [
"I'm sure there's a deep quantum-field-theory explanation of this that makes perfect sense, but I'm not qualified to offer it. Probably something about virtual photons be localized excitations of the electric field itself and not discrete particles emitted by sources of charge, or words to that effect.",
"But the... | [
"Simplistic answer",
":",
"It is known that black holes can have charge, and therefore a static electric field. The question is, how does this field escape the horizon? In that, I should remind you that the horizon is the surface through which one cannot send any signals. ",
"Now, signals (i.e. photons) invol... | [
"Have a look at the ",
"Virtual particles FAQ",
", in particular question 4 (\"Do they go faster than light? Do virtual particles contradict relativity or causality?\"). In which context, my guess would be that there wouldn't be a problem with a virtual photon \"crossing\" an event horizon: it doesn't ",
" ... |
[
"If transparent objects can refract electromagnetic waves of the visible spectrum, can they similarly affect other waves on the spectrum, say UV rays or X-rays?"
] | [
false
] | And on the other end of the spectrum as well - what sort of materials could affect radio waves and microwaves? | [
"You can actually do an experiment to show how infra-red radiation can be refracted. Take a prism and shine a white light through it, to make a rainbow. If the light is strong enough, you'll find that the area just past the red band is warm after some time, even though there's no visible light hitting it."
] | [
"Conductors also have an affect on EM waves. They do not necessarily refract, but they can block. The metal mesh around your microwave generates image currents that prevent the waves from leaving the cage."
] | [
"Be aware that 'transparent' actually means 'transparent for a certain range of wavelengths'. Usually, that means the visible part of the EM spectrum between 350 and 800nm.",
"But yes, materials that do not strongly absorb a wavelength will refract it according to the refractive index."
] |
[
"If someone adds an addictive substance to your food without you knowing, how would your mind react, would it get you addicted and how would it know what exactly you are addicted to?"
] | [
false
] | null | [
"Hi Gone4Gaming thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the fol... | [
"Psychology"
] | [
"‘Psychology’"
] |
[
"Why do I experience short bursts of \"dizziness\" before going to sleep?"
] | [
false
] | null | [
"Welcome to AskScience. Please make the titles of your posts descriptive, and ",
"Unfortunately we cannot provide any diagnosis or other information for you. There is almost always a way to make your way into a free clinic presuming you're in the first world."
] | [
"You're right, sometimes the community gets it right. That said there is NO WAY they can properly diagnose you via reddit, it's impossible and dangerous and if it was allowed, sooner or later it WOULD harm someone, it's only a matter of time.",
"I understand your concern of course, but believing that nothing wou... | [
"Providing medical advice is against the Reddit TOS, not a specific rule to this subreddit. I would not trust medical advice from the internet, and anyone who claims they can diagnose you is full of shit. ",
"There are too many variables to make an appropriate diagnosis from your post, or any post over the inter... |
[
"Why, neurologically, do people urinate when extremely frightened?"
] | [
false
] | [deleted] | [
"Urination and defecation is an instinctive mammalian response in order to make you less appetizing to predators, and to signal to others that danger is near. Neither are terribly relevant for humans anymore, but the instincts remain."
] | [
"The short answer is it's not your brain doing it. Your brain finishes with the business after it tells your body that it's scared. After that your adrenal glands (sitting on your kidneys) take over and start pumping out epinephrin which causes you heart rate to increase, your breathing to hasten etc. One of the... | [
"Thanks for your comment, but I am looking for a more technical description of the biological happenings in the brain associated with those instincts you mentioned."
] |
[
"With all these beautiful colors you see in pictures of nebulas in /r/space, what colors will your eyes actually see of those objects in space?"
] | [
false
] | For example: | [
"We image the sky in the entire spectrum of light; may it be microwave, gamma, infrared, UV, radio, visible, etc. Each apparatus is different of course. ",
"So if the picture is taken in the visible spectrum those indeed ",
" the ",
" colours. \nWe humans see a very small piece of the entire light spectra, b... | [
"I like to think about when you blow smoke through a dense beam of light and you see all the complex patterns the smoke makes as it swirls around. These patterns are all around you all the time but since it occurs in the invisible gas that is our atmosphere we rarely get glimpses of this complex pattern. The smoke ... | [
"Thank you! Exactly what I was looking for!"
] |
[
"Is a 128 Gb memory stick just made up of two 64 Gb chips \"glued\" together or is it an entirely different technology that suddenly occupies half the space?"
] | [
false
] | Memory sticks are so big on comparison to the chip inside them, so I guess they could stick 10 chips in it and create the "biggest ever" memory stick rather easily... Edit: I'm happy that my most successful post ever on Reddit has been this unpretentious, near ELI-5 on AskScience, one of my favorite subs! | [
"I've worked in the storage industry, though not specifically on this type of device, so I might be missing a few minor details. Hopefully this will help, though.",
"A quick search found ",
"this",
" article which is focused on high-performance programming. SSDs are very similar in relevant ways to USB sticks... | [
"Speed. For example not all SD cards can transfer at the same rate, and if you get one that is too crappy, it may not work for some purposes (e.g. video recording). ",
"Number of times you can read/write to the memory can also vary."
] | [
"> Because in this space customers seem to care almost exclusively about price and capacity to the exclusion of all else ",
"As a consumer in this space, what else is there to look for?"
] |
[
"Why does interlocking my fingers one way feel so natural, but the other way feels completely foreign?"
] | [
false
] | null | [
"These answers suck.",
"He's asking why it ",
", not why he's right-handed..."
] | [
"I just looked around and found this - is it inaccurate? ",
"http://udel.edu/~mcdonald/mythhandclasp.html"
] | [
"I just looked around and found this - is it inaccurate? ",
"http://udel.edu/~mcdonald/mythhandclasp.html"
] |
[
"Can someone explain the \"Ultraviolet Catastrophe\" that led to the creation of Planck's Constant and the birth of Quantum Physics?"
] | [
false
] | I understand that contemporary theories of the time about how black bodies would radiate energy led to certain bodies radiating infinite amounts of energy, but what was it about those old theories that led to such a result? Every reference I have come across just brushes over this and focuses more on our understanding ... | [
"That has nothing to do with black holes."
] | [
"A black body isn't a black hole, but I can see the confusion. A black body is an idealized material, but many materials are close enough that we consider them black bodies. Basically, if you heat up a black body, it radiates that energy away as light. The hotter the body, the brighter the light and the shorter the... | [
"It's fairly simple - the model and equations they used said the intensity of the light from a black body should be be inversely proportional to the wavelength, raised the the fourth power. Thus, as wavelengths got smaller and smaller, the intensity according to the equation would very quickly approach infinity. Ob... |
[
"Does gravity affect how hard your heart pumps blood through your body? ie. is laying down less taxing, or say in a zero gravity environment?"
] | [
false
] | null | [
"Yes.",
"Within two to three days of weightlessness, astronauts can lose as much as 22 percent of their blood volume as a result of that errant message. This change affects the heart, too. \"If you have less blood,\" explains Dr. Victor Schneider, research medical officer for NASA headquarters, \"then your heart ... | [
"With average blood volumes for males being about 5 Liters, give or take based on weight, where does the liter of blood go in 2-3 days?"
] | [
"Yes. Your body has to fight gravity to pump blood upward while you're standing. When you experience hypotension (too little blood pressure) gravity wins, not enough oxygenated blood gets to your brain, you faint/fall over. Now your body has less work to do while face down, passed out in a public space. Your veins... |
[
"Why don't babies and puppies learn how to walk similarly?"
] | [
false
] | [deleted] | [
"This is a good question and it sheds light on the developmental stratagy of an animal and the evironment they exist in, ans how theyve adapted to it!",
"Dogs come from wolves, who generally need their young to be as mobile as possible as quickly as possible to aid in their survival.",
"Human babies need to com... | [
"I would have never thought about the size of the head as a factor for this.",
"I don't have a reference, but essentially, humans have comparatively large heads because of our large brains. That's a problem, though, when it comes to childbirth; given the way our hips are constructed, if the baby's head gets too b... | [
"I would have never thought about the size of the head as a factor for this.",
"I don't have a reference, but essentially, humans have comparatively large heads because of our large brains. That's a problem, though, when it comes to childbirth; given the way our hips are constructed, if the baby's head gets too b... |
[
"GMO's? Science on the subject rather than the BS from both sides."
] | [
false
] | I am curious if someone could give me some scientifically accurate studies on the effects (or lack there of) of consuming GMO's. I understand the policy implications but I am having trouble finding reputable scientific studies. Thanks a lot! edit: thanks for all the fantastic answers I am starting to understand this is... | [
"It all depends on the modification",
"I'm going to expand on that a little bit, because it's critically important. Every food crop GMO that I am aware of is transgenic; that is, the genes being inserted are not artificially created, they are instead taken from another plant (or animal) and inserted into the crop... | [
"The problem here is that there's no reason to treat \"GMOs\" as a cohesive group. You can use genetic engineering to insert all kinds of genes. The health effects, if any, will depend entirely on what genetic modifications you do. You can add a section of noncoding DNA which reads \"MCwaffle was here\" to corn ... | [
"I worked with GMOs for a period of time in the mid-2000s before exiting the field to pursue different work, largely because I got sick of trying to defend myself to strangers that magically became more qualified than me after seeing a YouTube video or documentary.",
"The quality of critique against GMOs is almos... |
[
"How bright is space? If I'm floating through the galaxy with my friend, would he be illuminated?"
] | [
false
] | null | [
"Depends on where in the galaxy you are. There will be some photons reflecting off your friend - that's evident because we can see stars in any direction.",
"But generally, yeah, you'd be able to see your friend, at least dimly. If you go out at night in the desert during a new moon, you'll notice that you can r... | [
"How bright is space? If I'm floating through the galaxy with my friend, would he be irradiated?"
] | [
"Uh, moonlight or starlight? If I go stargazing when the moon isn't out, I know it's too dark to read."
] |
[
"If obese people are in poor health because of excess fat, why can't this all be removed via liposuction or surgery?"
] | [
false
] | I was Googling this earlier and it says it's dangerous to remove lots of fat, but I couldn't find a good reason why. | [
"Fat can be dangerous to remove because it's not avascular - there are still blood vessels running through it and removing it will cause bleeding. In some parts of the body, there are large, superficial arteries and veins running in fat that a surgeon would be at risk of damaging. And fat doesn't just lay right u... | [
"The problem when obesity causes severe health issues (such as diabetes or cardiovascular disease) is not just excess adipose tissue (although this may be the root cause), but accumulation of fat in areas it shouldn't be because our normal adipose tissue storage areas have been \"overfilled\"; this ectopic fat accu... | [
"Could surgery do anything/remedy some of the latter problems you mentioned?"
] |
[
"If the earth is curving away from me in any given direction, why do I experience the horizon as being at eye level?"
] | [
false
] | I was standing on the beach, and I noticed that the horizon line felt to me that it was at eye level. But the earth curves away from me because I'm standing on a sphere, right? Can anyone explain the perceptual cockup that is occurring here? | [
"TL;DR - It's just a geometry problem. The radius of the earth is much, much longer than you are tall, so the angle at which you have to tilt your head to see the vanishing point of the horizon is very small.",
"I wrote the math up to explain it, but it is long and dense. Take a look at ",
"this diagram",
" t... | [
"Brilliant! Thank you!"
] | [
"This isn't a direct answer to your question exactly, but if conditions are clear you can actually see distant ships heading out to sea dip below the curvature of the earth on the horizon. "
] |
[
"What does the percent ionic character of a bond actually mean in terms of electron probability density?"
] | [
false
] | [deleted] | [
"From a molecular orbital theory standpoint, percent ionic character manifests in the coefficients of the atomic orbital wavefunctions that are used in the linear combinations forming your bonding and antibonding orbitals. For HF, what it means is that the filled bonding orbital is comprised primarily of fluorine'... | [
"My question is more on what does on mean in terms of probability densities. The electron isn't on fluorine, it's around fluorine in a molecular orbital. How does that 89% change the probability density in terms of bonding. How does the sp3 orbital containing that electron look? Is it literally just closer to fluor... | [
"Qualitatively, it means that the electron has a higher probability of being found \"on\" the fluorine rather than in the small area where there is orbital overlap. When I say \"on\" I mean that it will likely be in the fluorine domain of the orbital rather than the \"shared\" or overlapping area of the orbital. "
... |
[
"Is space quantified?"
] | [
false
] | I suppose that it is not, but then, when an object moves from position A to position B, does it traverse an infinite number of positions? If it takes time to move from one of these infinitesimal positions to the other, it would take infinite time to arrive to position B, right? How is this dilemma solved? | [
"Is space quantified?",
"We don't know if space is quantized or not. Currently, there is no evidence suggesting that it is quantized, so all of our best models assume that space is continuous. This includes both general relativity, and quantum mechanics (yes, you read that right -- quantum mechanics assumes a s... | [
"Imagine you divide the path from A to B into 10 equal divisions, and it takes you exactly 0.1 seconds to traverse each division. You'll go from A to B in 1 seconds. Now, divide it into 1000 divisions, and now it takes 0.001 seconds to traverse each divsions. You'll still go from A to B in 1 second.",
"As you inc... | [
"Awesome reply, what a pity that the post didn't succeed :)",
"You fully replied my doubt, although I still need to get my head around that infinitesimal stuff..."
] |
[
"Double-slit experiment and the speed of light"
] | [
false
] | The best way I can think of the ask my question is to set up a thought experiment, and have it explained why it is impossible. The following ascii illustration precedes the caption. Imagine a double-slit experiment, where one slit (A) is always open, and there are two more slits (B) and (C) where exactly one of (B) and... | [
"Surprisingly, no one has mentioned ",
", but this question all comes down to coherence. Waves interfere when (1) they have the same frequency, and (b) they are locked in (relative) phase. Otherwise they average out to some nominal amplitude, and the patterns wash out.",
"You should know that with modern synchr... | [
"What influence do slits (B) and (C) have on the diffraction pattern, given that they are further away from (D) than (A) is, and understanding that light going from (X) to (D) through (A) is as fast as possible?"
] | [
"This one really hit it on the head for me, great explanation."
] |
[
"Help me understand time."
] | [
false
] | So I was reading Hawking's Brief History of Time, but can't get my mind around how gravity affects time. For instance, GPS satellite clocks run faster in orbit than clocks on earth because they experience less of the earth's gravity. Why? I imagine a simple clock where say a crystal vibrates at a certain frequency, a m... | [
"Maybe the electrons powering the clock move faster with less gravity?",
"Firstly, stop trying to think of a mechanical explanation; it has nothing to do with how gears or electrons move. Time ",
" slows down, and the effect can be shown to apply to things that have no moving parts whatsoever, like a single at... | [
"to be specific: gravity doesn't \"bend\" it at all. Mass-energy does, and gravity is just a derived result ",
" that bending."
] | [
"We've discovered that space and time are not independent. We live in something called a spacetime ...",
"http://en.wikipedia.org/wiki/Spacetime",
"Gravity bends this thing. So that's why gravity affects time.",
"It turns out this is really the best description of reality. Weird, huh?"
] |
[
"Whats left in the soil onece it becomes \"barren\" & can soil be truely \"barren\"?"
] | [
false
] | Thank god you guys are here, i was having a long thought out conversation the other day and came upon the concept of barren soil. Please explain this to me in a way i can understand! Lets start out with fertile soil; Now we plant plants until all the nutrients have been depleted, whats left in the soil? To my understa... | [
"Good soil is soil that is capable of supporting life, by definition, and barren or degraded soil cannot support life or not as well as it used to. There are a number of ways this can happen.",
"First, the main thing a plant needs from the soil is just water. It doesn't need all that much other stuff (\"nutrients... | [
"Thank you! this was the awnser i was seeking! :)"
] | [
"Remember that soil does not exist without life. Fungi, plants, and microorganisms originally broke down rock into “soil”. Today, soil is a complex mixture of old soil, dead plants, dead fungi, dead animals, dead microorganisms, silt and sand, urine and feces, and many other things."
] |
[
"Would there be any catastrophic events if the moon was wiped out?"
] | [
false
] | If the moon was all of a sudden gone, would it affect Earth in any major way? EDIT: Thanks for the replies! I know I don't want the moon destroyed now. | [
"animals would go batshit without the moon to guide their natural rhythms.\nwe would lose the tides, and more importantly the earth's rotation would be affected, we would start to wobble. right now the moon has a stabilizing influence on our rotation. The moon also acts somewhat like a shield for large meteors pick... | [
"Source for this? I'm pretty sure the moon does the lion's share of the work."
] | [
"One recurring nightmare of mine is a Deep Impact asteroid hitting the moon instead of the earth, everyone is happy, but the impact pushes the moon a little too much towards the earth. Long story short, it falls toward us."
] |
[
"How does Circadian Rhythm/clock work for the blind?"
] | [
false
] | If circadian rhythm is based mainly on the external stimuli of Sunlight/light, does it function well for the visually challenged? If so, how? | [
"The answer depends on the cause of the blindness. The brain's internal circadian clock is very accurate and will run by itself, but it is normally synchronized by outside sources, typically light. This can 'entrainment' can be done by rods and cones, and/or intrinsically photosensitive retinal ganglion cells (ipR... | [
"Doesn't skin have a feedback for light?"
] | [
"There was an article some years ago that suggested that, but all the evidence since shows that light on the skin cannot entrain the central clock."
] |
[
"What's the deal with cosmological constant? Does it still hold a value in the formula for General Relativity?"
] | [
false
] | For reasons that don't need to be introduced, I've been watching some videos about the cosmological constant. In every video I watch, the host will say something along the lines of "Einstein introduced this constant so that his equations would work under the assumption that the Universe was static. However, with Hubble... | [
"So Einstein's constant is no longer correct? A new constant is used that has a different value?"
] | [
"So Einstein's constant is no longer correct? A new constant is used that has a different value?"
] | [
"Makes sense. Thank you!"
] |
[
"What color is a neutron star?"
] | [
false
] | I understand that color is produced by interactions with electrons, but since a neutron star doesn't have a lot of them, what color will it be? | [
"Neutron stars are made of ",
"-degenerate matter",
" and are the result of a supernova and gravitational collapse of a large star. Using ",
"Wien's law",
" it is possible to calculate that most of the EM radiation emitted by a neutron star is in the x-ray range, and this is how we typically look for them (... | [
"You're forgetting that even though there is a redshift, there is also UV rays emitted that shift to visible blue. Together, the curve is near flat, which appears bluish white to the eye.",
"Neutron stars have been also imaged directly. It's made up that they would be visible only close by."
] | [
"Most welcome. I've not done astro in a few years now so I may have glossed over some things, so I'd welcome any corrections by actual astrophysicists.",
"As for reflection no, a neutron star would likely not reflect any light. Stars are considered \"good\" blackbodies meaning that they absorb all incident EM rad... |
[
"When light enters a black hole and then fails to exit it, would the black hole not cause the light to slow down below the speed of light which, should be impossible for light in a vacuum?"
] | [
false
] | null | [
"The geometry of space time inside the event horizon of a black hole is very different to \"normal\" space. Once you cross the event horizon, time and space do a kind of swap, meaning that no matter what direction you travel or how fast, you always move closer to the centre of the black hole. So once a photon cross... | [
"The light gets \"destroyed\", it stops existing when it hits the singularity (or whatever might be there)."
] | [
"This is one of the few extreme circumstances where you have to use general relativity to even get a reasonable approximation of what it happening. Here you can't think of gravity in the Newtonian sense where it is simply a force pulling objects closer (especially since gravity is effecting light which has no mass ... |
[
"Writing a short story featuring a neutron star. Need science advice."
] | [
false
] | I am writing a short story featuring a neutron star. Speculate; What would happen if a rogue neutron star entered our solar system? It's destined to slam into Earth and destroy it but along the way surely it would have other effects. If there are any scientists that would like to weigh in I would love your input and pr... | [
"Ignoring the phenomenal improbability for a second, it would almost certainly be travelling at breakneck speed, so the effects would be brief. Without more details it would be exceptionally difficult to give you an accurate answer, as speed, mass, trajectory, current planetary positions etc all make a large differ... | [
"Incidentally, I own said program and just tried it a couple of times. Both times it ended up pretty much scattering the planets and chucking the sun off in a random direction as well. The planets either follow the path of the sun or the path of the 'intruding' star, depending on where they are at the time and how ... | [
"As the other posters have pointed out, the effects depend heavily on the path that the neutron star takes through the solar system. Any path could potentially be devestating, but there are two which lead to particularly spectacular results.",
"1) The obvious one: the neutron star comes close to the earth. First ... |
[
"How does the ISS handle debris on its solar panels? How often does the ISS get hit with debris?"
] | [
false
] | null | [
"Hey, this question is right up my alley!",
"Bit of background: I've done testing and analysis for the ISS program on this exact topic, including hypervelocity impact testing into ISS solar cells at NASA's White Sands Test Facility back in 2014.",
"Second question first: the ISS gets hit more or less constantly... | [
"A brick sized object would be, depending on where on ISS it hit, anywhere between devastating and nearly instantly catastrophic.",
"Fortunately, most objects that big, of which there are relatively few, are able to be tracked, so we can see them coming and get out of the way.",
"Most of the stuff that hits ISS... | [
"A brick sized object would be, depending on where on ISS it hit, anywhere between devastating and nearly instantly catastrophic.",
"Fortunately, most objects that big, of which there are relatively few, are able to be tracked, so we can see them coming and get out of the way.",
"Most of the stuff that hits ISS... |
[
"Would arrows to indicate direction and/or movement (specifically on the pioneer spacecraft) really be unintelligible to non-humans?"
] | [
false
] | [deleted] | [
"I doubt they could understand it, for many reasons.",
"Now, we can't actually do experiments on extra-terrestrials to answer questions like those, but we could do it on children which do not have any preformed cultural conceptions. I can only offer anecdotal experience, since I have a kid myself and I can tell ... | [
"Any discussion of the psychology of non-terrestrial intelligences is going to be speculative as hell. A sapient alien species might well be able to interpret an arrow as indicating movement; alternatively, they might not be able to understand symbols at all. We just don't know. With that in mind, I think arguing t... | [
"Sounds contrived to me. Your examples with children and the rosetta stone are irrelevant. Children lack experience and to some extent intelligence and symbols are different from newer writing systems.",
"I think you underestimate intelligence and deductional skills."
] |
[
"How do wild creatures get through unusually cold weather?"
] | [
false
] | The Northeast US is having an unusually long, deep cold snap. Humans and domestic pets are holing up inside, farmers are keeping cows in the barn -- but what about the wild birds? The deer and the chipmunks? Which species are unphased by this, going about their usual business? Which ones are taking special measures? Wh... | [
"I can weigh in on birds. :)",
"Birds’ feathers provide excellent insulation against the cold, and many species grow extra feathers in the late fall to give them more protection during the winter months. There is also an oil that coats birds’ feathers which provides insulation as well as waterproofing. This is ex... | [
"Bees form a ball inside their hives where they all huddle together and swarm around one another to keep warm. The bees in the middle get to be warn and sleep while the bees on the outside do the work, and then they rotate in and out in shifts."
] | [
"So basically, the feet get less warm this way (but less heat loss also, as heat loss is based on the temperature difference between 2 objects). The heart also gets less chilly blood returned to it, so less thermal shock."
] |
[
"One thing astrophysicists/theorists never talk about when discussing interstellar travel is how hard it would be stop a ship traveling at close to the speed of light. Is it somehow easier to slow a ship down than speed it up? Have any potential methods for doing this been discussed?"
] | [
false
] | [deleted] | [
"If you have a ship capable of reaching relativistic speeds, slowing down is the least of your worries. In fact, slowing down is dead easy. Just use attitude jets to turn the ship around, and fire the engines pointing the other way. ",
"The only caveat there is that you have to start firing the engines in reve... | [
"That is truly one of the big outstanding problems to the field. Because at those speeds, realize that what you have isn't so much a pebble hitting your windshield but a collision in a particle accelerator. The atoms of the thing you're \"hitting\" smash into the atoms of your ship and produce a ",
" of very hard... | [
"That is truly one of the big outstanding problems to the field. Because at those speeds, realize that what you have isn't so much a pebble hitting your windshield but a collision in a particle accelerator. The atoms of the thing you're \"hitting\" smash into the atoms of your ship and produce a ",
" of very hard... |
[
"Ac vs DC"
] | [
false
] | How come since all of our appliances us DC power and the electric companies send us AC current don't we just put a convertor on our house? That would save us space with all of our appliances not needing those huge power bricks. | [
"Lots of the power usage in you home requires AC, such as your refrigerator, air conditioner, etc."
] | [
"It's worth clarifying some of the replies so far. Transmission of DC is more efficient than transmission of AC. Alternating current, by definition, has to change directions in the power lines. This change doesn't happen instantly, and is governed by the ",
" of the lines. Changing a voltage across a given in... | [
"Some appliances actually don't use DC power, it is also much cheaper and more efficient to send AC power. Transformers, which are used to efficiently facilitate the transportation of electricity by being able to step up or step down the voltage, require AC. Transformers are common in power lines but some appliance... |
[
"Why isn't nanocoating more common (yet)?"
] | [
false
] | The last few years I have seen many videos/articles showing off the effects nanocoating have. As in clothes that can't get dirty, cars, all kinds of objects. But why is it that this isn't or at least seems to be not that common. Also I've heard they already put it on cars, but often it doesn't seem as effective as some... | [
"At least with the ultrahyphobic materials, the biggest problem is adhesion. The problem with nothing sticking to your coating is that your coating doesn't stick to surfaces! ",
"There are chemical ways of doing these adhesion, but it's hugely different to do something in a lab and on an industrial scale. Devel... | [
"I will assume the glass coming off the plant is silanizable, ",
"I don't know of any glass that cannot be silane modified, would love to hear of one if you know of it.",
"A bigger problem than all the issues you described is lifetime. A nano-coating is not mechanically robust. It will deteriorate and scratch a... | [
"Dirty glass can't be effectively silane modified. Hence a definite requirement for cleaning if being moved sites, and a probable requirement even if coming straight off the line. Further more yes this is what we are talking about. The difference lies in coating versus surface modification. Surface modification... |
[
"How does an electric arc choose it’s path in air (ex: a lightning bolt or Tesla coil)?"
] | [
false
] | They all seem so very random, but is there an actual scientific or mathematical equation for the path/arc they create? Or is it just randomly jumping from one molecule to the next? | [
"First, watch the video linked by ",
"/u/sxbennett",
" - it's an amazing video showing what happens in a lightning strike. I've shown that same video to many others in the past to illustrate what's going on.",
"But in more detail: The air in our atmosphere is non-conducting in general, so charges can build up... | [
"If you watch a ",
"slow-motion video",
" of a lightning strike, you'll see that before it hits the ground it sends out small \"feelers\" that go out somewhat randomly, but mostly downwards. Once one touches the ground, the path it took gets very bright (this is the most visible part of a lightning strike) as i... | [
"Not a studied scientist, but as I understand it:",
"Electricity usually takes the path of least resistence. ",
"Imagine water-molecules randomly moving around, bumping into each other and creating random volumes of slightly more or less density. ",
"Lightning is caused by a difference in electric potential b... |
[
"Would it be possible to throw a baseball around the moon into orbit?"
] | [
false
] | Hi I'm new to so I apologize if this is poor formatting or has already been asked. Aroldis Chapman currently holds the record for fastest pitch at 105.1 mph, (Hypothetically) If he was standing on the moon would this be enough to launch the baseball into orbit around the moon because of the moons decreased gravity? If ... | [
"What you need is the lunar orbital speed, which is 1.7 km/s. That's still over 36 times faster than the fastest pitch."
] | [
"If this is a contest, ",
"S/2009 S 1",
" has a mean diameter of 400 meters. Assuming it's spherical and made of ice, escape velocity should be about 0.1 m/s."
] | [
"If this is a contest, ",
"S/2009 S 1",
" has a mean diameter of 400 meters. Assuming it's spherical and made of ice, escape velocity should be about 0.1 m/s."
] |
[
"Is it possible to contain and harness the energy from a sun that is small enough?"
] | [
false
] | null | [
"I'm not sure what this question is asking. Could you clarify? All of our energy ultimately comes from the sun, and we have harnessed and contained it."
] | [
"I'm curious if it is possible to use a much smaller sun in place of nuclear plants, or hydro plants etcetera. Or to use it for other purposes. "
] | [
"This is far too speculative for our panelists to answer. The smallest stars are still larger than most planets. There's nothing that would be the size of a power plant."
] |
[
"Does the gradual movement of the Magnetic North Pole alter climate in any way?"
] | [
false
] | null | [
"No. The magnetic poles are entirely different from geographic poles. The motion of the elements in the core would not be sufficient to alter Earth's spin, it's angular momentum will always be conserved."
] | [
"there has been more geological activity",
"[",
"]",
"Especially under Yellowstone",
"From the actual ",
"Yellowstone FAQ",
" site:",
"\"Another caldera-forming eruption is theoretically possible, but it is very unlikely in the next thousand or even 10,000 years.\""
] | [
"Thanks!!"
] |
[
"Scientists 'split' the electron? I don't believe it, what can r/askscience tell me about this story?"
] | [
false
] | I don't believe it, this would be all over the news if it were true. | [
"Science reporting is really really ",
" bad; even if it's from a more reputable news source, you should treat it with about the same credibility as your friend's fishing stories. The article is just completely wrong, and completely misrepresents what was actually done."
] | [
"I can't claim to understand the specifics of the paper, but I understand the journalist's problem.",
"Basically, all fundamental particles, like the electron, are described as excitations in a fundamental field. A reasonable analogy is ripples on the surface of a pond or pulses traveling along a stretched string... | [
"In the solid state, there are a variety of pseudoparticles--that is, propagating effects (like an ",
"exciton",
" or a ",
"phonon",
") that behave like particles and can be theoretically modeled as them. When you deal with solid state systems that are very small, you begin to see strange confinement effect... |
[
"Does the amount of time it takes an ice cube to melt directly proportional to it's temperature?"
] | [
false
] | Would an ice cube that had been stored at 0 degrees F melt more slowly than one that had been stored at 10 F? If so, what's the mathematical nature of this relationship? Edit: Apologize for the grammar in my title. | [
"A good way to perceive this is that the melting point of a material (at whatever pressure) is the temperature at which its liquid and solid phases can coexist in thermal equilibrium (i.e. no net energy transfer)"
] | [
"So what happens if you add an amount less than 344.774 J but greater than ~2.1 J (say, 210 J) to 0C ice? "
] | [
"So what happens if you add an amount less than 344.774 J but greater than ~2.1 J (say, 210 J) to 0C ice? "
] |
[
"Why don't animals like rams get concussions when they run head first into things? Can we build helmets based on their ability to protect athletes?"
] | [
false
] | null | [
"Livescience",
" did a piece on why woodpeckers don't get concussions from constant head-banging. To sum the evidence from that article, the bird's neck has strong muscles that absorb shock, the peripheral components like beak and eyes are cushioned by tertiary structures which prevent impact damage, and most imp... | [
"and also dont the tongues of woodpeckers wrap around the skull?"
] | [
"I don't know why you have -4 points, I've seen multiple sources that state that the tongue moves to the back of the head",
"http://www.birds.cornell.edu/wp_about/biology.html",
"http://www.talkorigins.org/faqs/woodpecker/woodpecker.html",
"Edit: Huzzah he's positive, reddit understands!"
] |
[
"What's the difference between infrared heat and warm air heat?"
] | [
false
] | [deleted] | [
"There is no such thing as \"infrared heat.\" Heat is a type of energy that corresponds to how fast things are \"jiggling around.\"",
"In order to make it so the components of a system \"jiggle around\" at about the same rate as its surroundings, the system will absorb/give off heat. ",
"There are three methods... | [
"Warm air can radiate in the infrared range, but it depends how warm the air is. Most heat transfer in gases is through convection.",
"And yes, the sun is extremely hot. It radiates across the entire EM spectrum, peaking somewhere in the visible light region (which is probably why we evolved to see the region of ... | [
"Warm air can radiate in the infrared range, but it depends how warm the air is. Most heat transfer in gases is through convection.",
"And yes, the sun is extremely hot. It radiates across the entire EM spectrum, peaking somewhere in the visible light region (which is probably why we evolved to see the region of ... |
[
"Does time travel slower at the center of galaxies?"
] | [
false
] | [deleted] | [
"If time travels slower when nearer to high gravitational masses, does time travel slower for things nearer to the center of galaxies where there is a high density of stars and perhaps a supermassive black hole? ",
"Yep. Spot on.",
"And, more of what I'm really trying to get at here, does this affect our percep... | [
"Does the velocity time dilation completely cancel out with the gravity time dilation, or does one \"overcompensate\" the other, like with the satellites around Earth?"
] | [
"My guess would be yes, I've thought about these kind of things myself. There's never such a thing as \"Zero-G\" though; and I'm not sure how much of a difference you'd have being in some orbit around the SMBH in the center of the galaxy and standing on Earth - as there is very very little difference until you're ... |
[
"How do we determine the next word we want to use when we speak?"
] | [
false
] | I was talking to a friend about the process we use in our minds to determine the next word we want to use when we speak. He thinks it works more by raw, brute elimination. I think it works more like a Markov chain where we store words commonly used after another word/phrase. I.e. to say "How are you": His method: How -... | [
"There is quite a lot of research on language production, and it's not my particular area, so I can only give a very general answer.",
"First off, we can rule out a naive Markov chain model which would be based on a linear sequence of words. If there is one clear finding, it is that we both produce and perceive l... | [
"I've noticed that when in an enclosed space, you will often hear the same word be used in quick succession by two speakers in two different conversations within earshot of each other. ",
"Example:\n2 people, a and b talking in one corner, \n2 people, c and d taking in another ",
"A to B: I find that we have to... | [
"[Cognitive Psych PhD who focuses on language about half the time]",
"This question is much too broad to answer effectively in a reddit post, apologies, it's a bit like \"How does your liver know what molecule to make next?\" or \"Which piece of wood will a hurricane pick up next?\" or something. It's VERY comple... |
[
"If the sun suddenly disappeared, would it take 8 minutes for us to feel the gravitational effects?"
] | [
false
] | null | [
"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",
... | [
"Please use the search function. This exact question has been asked here countless times."
] | [
"Thank you! :)"
] |
[
"gDNA preparation: Why is fragmentation required?"
] | [
false
] | During preparation of gDNA for NGS library construction, why is it important for the gDNA to be fragmented? | [
"Fragmentation is performed before most NGS sequencing not just gDNA sequencing, it's also done for things like ChIP-seq* and RNA-seq.",
"Most sequencing machines (like Illumina's ",
"sequencing by synthesis technology",
") can only sequence small reads, up to about 250bp at the most. 100 is very common and ... | [
"This will depend on what type of library/sequencing application you are using the DNA for. In some cases, it has to be broken and re-ligated to itself in small loops for the technology to work, in other cases, tags have to be added to the ends.",
"In any case, breaking the DNA into smaller fragments will make yo... | [
"Thank you! Very helpful explanation :)"
] |
[
"Is it possible to come up with a scientifically perfect diet for optimum human function?"
] | [
false
] | null | [
"No. There is too much genetic variation in the metabolism of certain compounds to develop a single perfect diet. It is possible to develop personalized diets once we have a firm grasp on the above mentioned metabolic variations. But where's the fun in that? I'd rather have a steak than a bowl of goop :)"
] | [
"I think he was looking for something a little more specific"
] | [
"To add to scarabear's answer, variations in environment, gut-flora, circadian rhythm, nutrient absorption etc. all affect what each individual needs and when they need it. There is evidence which supports the idea that humans have functioned well off of diets ranging from high fat/low carb to low fat/high carb so ... |
[
"What are the gases in bloated Lithium-Ion batteries?"
] | [
false
] | null | [
"This happens when lithium in the battery reacts with moisture in the air. Lithium reacts with water to form hydrogen gas and lithium hydroxide. Since lithium is so reactive with water, lithium ion batteries must be air-tight so that water can't get in, but sometimes it gets in anyways. The reaction of lithium w... | [
"Just to note, the products of water ingress are much more toxic than just hydrogen. Water catalyses a cascade of reactions that produce nasty compounds. The lithium exists as LiPF6 usually in batteries and decomposes by the following equations:",
"LiPF6 --> LiF + PF5",
"PF5 + H2O --> POF3 + 2HF",
"You do not... | [
"Assuming no other faults, bloating of the battery is due to degradation of the electrolyte at the anode and cathode.",
"Gases at the anode include H2, CO, olefins and alkanes.",
"Gases from the cathode is predominantly CO2. ",
"The reactions for these contain a lot of assumptions like what the solvent actual... |
[
"Why Don't Organs Feel Fatigue Like Muscles?"
] | [
false
] | Perhaps I worded this question in a bit of an odd manner. As an avid powerlifter and bodybuilder, I know muscle soreness (more specifically DOMS - delayed onset muscle soreness) like it's the back of my hand... or arm... or leg. You get the picture. But while I was in the shower today, hurting like nobody's business fr... | [
"3 things: ",
"A lot of organs aren't muscles.",
"It's comparitively hard to put strain on organ muscles, compared to movement muscles.",
"We lack the required nerves to feel muscle soreness in most internal organs."
] | [
"Well that was quick and painless. Thanks for the answer!"
] | [
"To answer your bullet points (since the guy above hit the nail on the head) you can make some organs hurt.",
"Sensory organs like your eyes and ears can get sore from over stimulation (e.g. Going to a concert, staring at lights) so this kind of counts as overuse? You're subjecting them to more stimulation than t... |
[
"Do super viruses like the one seen in The Stand exist? And if so why do we create them?"
] | [
false
] | For those not familiar with the book a super flu is released in a government lab that kills most of the worlds population. The virus was designed to overcome defenses and adapt to counter them. So I was curious if science does have these sorts of viruses and what the point of them would be? | [
"The creation of a \"super virus\" happened late last year and controversy surrounded it for months. It was a type of bird flu that was extremely dangerous. Scientists created it to study what evolutionary steps a virus would have to take to get to an \"Armageddon virus\" state. ",
"Modern labs (BSL-4 labs) that ... | [
"\"Scientists created it to study what evolutionary steps a virus would have to take to get to an \"Armageddon virus\" state.\"",
"Perhaps too subtle, but that's what I was saying, here. ^"
] | [
"\"Scientists created it to study what evolutionary steps a virus would have to take to get to an \"Armageddon virus\" state.\"",
"Perhaps too subtle, but that's what I was saying, here. ^"
] |
[
"What is the real benefit of shivering when it's cold?"
] | [
false
] | I learned long ago in school that when our muscles shiver, it generates heat. What I'm now wondering is, how would we be affected by the cold if we were incapable of shivering? Would there be a significant difference in our body temperature? | [
"We would still maintain homeostasis, but we would be forced to do it through different mechanisms. Shivering is a simple way of generating heat by muscle use.",
"Human infants and hibernating animals use ",
"non-shivering thermogenesis",
" to generate heat."
] | [
"I'm digging through some old notes and textbooks to try to find the data for humans, but in the meantime animal studies should be sufficient for your answer.",
"In normal environments (as ren5311 linked to) non-shivering thermogenesis is adequate to maintain homeostasis (constant core temperature). However, shiv... | [
"Way off. Goosebumps don't make you heavier. I think the world your looking for is \"volume\", and still no.",
"Goosebumps are a vestigial reflex from when we had hair covering our entire bodies. What produces goosebumps in humans forces all the hair to stand up in other animals, trapping air between the strands ... |
[
"Phases and concentration gradients"
] | [
false
] | I know that a phase is a body with a specific composition distinct from its surroundings. But what about a tank of saltwater that is saturated at the bottom, with concentration falling linearly until it reaches zero at the top? Does that count as one phase? Not a phase at all? | [
"It's a solution. So long as the salt doesn't precipitate out, the intermolecular picture is a constant picture from saturated bottom to unsalted top. If there were precipitated moistened salt environment under the water, that layer would function as a separate phase, as the salt dominated behavior of the solution ... | [
"Great answer. What about with sugar instead of salt? A saturated sugar water solution at room temp contains a good deal more sugar than water, so is the solution sugar-dominated at that point?"
] | [
"Well, with alloys, where two metals are mixed into a solution, you can have a phase in which the crystalline structure of either contributor can dominate any given crystal grain, with the other component(s) mixed in as defects. So, my guess is that this sort of phase dominates around the saturation point of water.... |
[
"Why can't we make a balloon that never loses air or helium?"
] | [
false
] | Inspired by . Won't it be sad when it droops away into a meaningless pile of rubber? WON'T YOU SAVE THE DINOSAURS, ASKSCIENCE?! | [
"There's a process called permeation where the gas molecules or atoms actually move through the interatomic spaces of the enclosing material. This puts a limit on ultra-high vacuum systems, but is also relevant for balloons. "
] | [
"Also helium gas diffuses through solids at a fast rate due to the molecule's small size and is used to detects leaks in industrial settings"
] | [
"They use metric as well. You should be proud, Americans get to learn two ways of doing the same thing!"
] |
[
"Why does the colour of a laser change, when the laser is shining through olive oil?"
] | [
false
] | [deleted] | [
"What you are observing is fluorescence from the chlorophyll present in the oil."
] | [
"That's awesome!"
] | [
"Hah, i'm doing a social service project as part of my ochem lab where we teach secondary school kids about fluorescence. We're using red, green, violet lasers, a black light and run up the mill highlighters. You can try it for yourself, it's inexpensive (plus the violet laser is awesome) and it's awesome. One of o... |
[
"Why is baking soda used so frequently as a cleaning agent?"
] | [
false
] | I know baking soda is sodium bicarbonate, and when mixed with water forms a basic solution. What I don't understand is why this solution would be good for, say, cleaning grease/oil off a stove. Can baking soda and water itself act as an emulsifier? Also, I don't know if this is related or not, but how does baking sod... | [
"Baking soda is also used as a cleaning agent because it is abrasive when made into a paste (when fully dissolved it is basic/alkaline so it dissolves grease).",
"As for use as a deodorizer, most foul odors are acidic or basic molecules, both of which baking soda can neutralize (and make less smelly). It can hand... | [
"Why or how?"
] | [
"In a word, saponification."
] |
[
"Theoretical questions about the transfer of data between two points."
] | [
false
] | null | [
"Would it be possible to send and store data with light without that wire?",
"Kind of like a wireless fios? ",
"Sure, for example via laser. ",
"If that was possible could we put some kind of orb in space that could send light pulses like the sun throughout the solar system and act as a sort of a galactic int... | [
"It's most definitely possible, although you'd want a laser or possibly some other form of radiation, the idea of light based data transfer is used quite commonly, one example is an opto isolator, another would be a laser modem. These methods aren't too efficient for a galactic internet, so to combat that you'd wan... | [
"You can't transmit information through quantum entanglement."
] |
[
"What is the purpose of these tendons connecting each finger to one another, like in this gif? [GIF Included]"
] | [
false
] | null | [
"These are the tendons of the extensor digitorum, the muscle that helps you extend your fingers back towards the top (dorusm) of your hand.",
"The connections between them are cleverly named as the \"intertendinous connections of the extensor digitorum.\"",
"They are part of the reason you cannot move one finge... | [
"Ohh that's pretty interesting. Is there a specific purpose to those little connections between fingers? Thanks for the answer! I saw a similar gif a while ago and I've been curious about it. It always baffles me how complex the human body is."
] | [
"Thanks for the replies, man!"
] |
[
"What would happen if one face of the Earth faced the sun year round, for ever?"
] | [
false
] | What if a planet like Earth (ok let us say plain old Earth), at its current distance from the sun, orbited the sun in a way that only one face of it ever only faced the sun (like the Moon orbits the Earth). Assuming the poles were at a right angle from the point of the earth that faced the sun at all times. What woul... | [
"Here's a better answer: ",
"http://www.lifeslittlemysteries.com/2491-world-stopped-turning.html"
] | [
"that would be bloody hot on day side, I could crunch the math if you want to, but there would be a lot of factor to think about"
] | [
"you can ignore the more complicated stuff. i am just looking for a rough estimate. i have been considering this for a long time and am greatly interested. but if it would be too complicated or tiresome then never mind. "
] |
[
"How does a Kale, a Cabbage and a Brussels Sprout still belong to the same plant \"family\" while displaying such varied structures and growth patterns?"
] | [
false
] | How did they become so different? Did they all start from a common ancestor or did they evolve parallel to one another? | [
"Wooh! An answer I finally actually know. So all three of them are descended from the same common ancestor. Which is actually still very common today. They all come from the wild mustard plant. I’m not sure how long ago, but at some point after humans began agricultural practices we realized that if you place t... | [
"They're not just in the same family (Brassicaceae, which also includes things like mustard and radishes), they're actually the same exact species, ",
".",
"One thing to keep in mind is that the vegetables you buy in the store are all different parts of the plant. Kale is the mature leaves, cabbage is an apical... | [
"If they have a common ancestor, and they were created by selective breeding, does that mean they could still be bred together today? As someone stated in a different comment, they're exactly the same species. ",
"So could I plant some kale near some brussel sprouts and cabbage, and somehow eventually get a chi... |
[
"What is the purpose of Restriction Sites in DNA?"
] | [
false
] | All I can get from my textbook and Wikipedia is that the Restriction Enzymes are thought to have originally evolved as a defensive mechanism against viral invasions, but why are there Restriction Sites at all? Is it used in DNA replication? In repairing damaged sections? | [
"Restriction sites are just specific DNA sequences that are targeted by the enzymes. The sequences occur naturally in the DNA. You have to think of it the other way around: the enzymes evolved to target certain DNA sequences that are unique to a genome or genome location. For example, the sequence AGGATA may occur ... | [
"I'd like to add that the bacterium protects its own genome from the restriction enzymes. Restriction sites in its own genome are often methylated (usually on C's, I think that's the one that is generally methylated but I'm not sure) which means that the enzyme will recognize and cleave restriction sites of viral o... | [
"Keep in mijd viruses do not have their own DNA replication machinery so they have to use that of a host. Therefore, the virus introduces its DNA into the cell and makes it code for virus proteins. Restriction enzymes are a form of defense against this."
] |
[
"Epilepsy: Effects of a seizure on consciousness/awareness"
] | [
false
] | null | [
"This article",
" does a decent job of summing up definitions of various seizure disorders.",
"Basically, the ",
" of a subclass of seizures (complex) includes an alteration of consciousness. Generalized complex seizures are defined by a loss of consciousness. Focal-onset partial seizures do not involve an al... | [
"Thanks. Do you know more about the transition from the lower to the higher states? Do patients get halucinations?"
] | [
"I'm not sure what you mean by \"lower to higher states\", can you expand on that?",
"Yes, patients definitely can have hallucinations (auditory, visual, olfactory). In the context of a seizure, these are often termed \"auras\", and usually occur right before the onset of the seizure episode. Usually, these hallu... |
[
"Am I reading this article incorrectly, or does a reaction involving only 6 molecules give off the same amount energy as a 7-layer burrito?"
] | [
false
] | null | [
"Energy values for reactions are almost always quoted per mole. So one mole of H",
"S combines with four of FOOF to give that amount of energy. It's not suggesting that one molecular reaction event gives that much off."
] | [
"H",
"S+4FOOF→SF",
"+2HF+4O",
" (+433kcal).\nHere, 314g of reactants result in 433kcal. This is a lower energy density than a 7-layer burrito, which has 283 grams and yields 510 kcal. The difference is in the activation energy and speed of the reaction.",
"edit: subscripts"
] | [
"That is for every 602000000000000000000000 molecules."
] |
[
"i was reading an article that mentions GABA and how different isoforms mediate “fast” and “slow” hyperpolarization. what is meant by “fast” and “slow” in the context of hyperpolarization?"
] | [
false
] | null | [
"Could you link the paper? It is hard to know what you are referring to based on this question alone. I'm guessing you are talking about fast or slow afterhyperpolarizations, which are usually mediated by different types of calcium dependent potassium channels with faster or slower kinetics. I suppose you could als... | [
"https://pubmed.ncbi.nlm.nih.gov/16402094/",
"I also wanted to clarify; My P.I. referred to benzodiazepines as an agonist of GABA, but this paper mentions that they potentiate GABA by increasing channel frequency; this is confusing to me and i have to present an overview of it at our lab meeting on friday. Thanks... | [
"I agree with the paper, I don't think I would technically call it an agonist. ",
"Read sections 6, 7, and 8 of this more recent review",
" for a better explanation."
] |
[
"Is mercuric chloride as dangerous as mercury?"
] | [
false
] | null | [
"Mercuric chloride - like mercury salts in general - is more toxic than metallic mercury. Metallic mercury tends to go through the body and come out the other end with limited effect, but soluble salts get absorbed and cause serious poisoning."
] | [
"On a continuum Mercury salts are less dangerous than organic forms of mercury. Methyl Mercury is poisonous to a greater extent than Mercury salts. ",
"One measure of how dangerous a chemical is called LD 50. This is the amount of a substance required to kill 50% of some thing. Generally rats, mice, or guinea pig... | [
"Mercuric chloride is toxic, so you should be careful when handling it. It's a solid at room temperature and I would recommend masking up whenever you work with any powdery or crystalline solid that can get in the air and into your lungs while working with it, regardless of its overall toxicity (also, the Wikipedia... |
[
"What does it mean to \"be Bayesian\" in terms of a way of thinking?"
] | [
false
] | I'm familiar with and how it's used in problems, but I've heard people talking about having a Bayesian way of thinking in general, or statisticians subscribing to a Bayesian way of thinking. What exactly does this mean? Is there more to Bayesian reasoning than just solving probabilities? | [
"Frequentists, the usual sort of statistics, define probability as the long-run average of a lot of repetitions of an event. ",
"Bayesians define probability as the degree of belief; a subset of them argue that these beliefs are largely personal, and only asymptotically approach the same value with repeated obser... | [
"To expand on this, frequentists are not limited to long run averages. ",
"To make inferences on an unknown population parameter, a sample is collected from the population and one of a number of estimation techniques are used. The most common one being maximum likelihood estimator, which is the value of the param... | [
"Thank you! The second kind hits the nail on the head because I've also heard it discussed in regards to building a model for automation or robotics, so that makes sense."
] |
[
"Why do the electric field lines at the end of two parallel plates curve?"
] | [
false
] | I believe it is called the end-effect? However I would like to know why this happens. Here is a picture of what I mean: Edit: Thank you all very much! | [
"If you're inbetween the plates at the centre, and the plates are much wider than their distance, they are well approximated by infinite parallel plates and so the field lines are straight.",
"If you instead zoom out and look at the whole thing from a distance, they look like an electric dipole, whose field lines... | [
"To add to this, and get an intuitive idea of why these tow limits have these shapes, you can consider a point charge. ",
"https://upload.wikimedia.org/wikipedia/commons/d/d9/Electric_field_of_a_point_charge.svg",
"Its pretty democratic and spreads out in all directions. Now imagine if you stack three of them t... | [
"Just finished up engineering physics at college.. the field lines are an average vector of the sum of the forces acting on a particle. When the proton reaches the top it wants to get as far away from it's positive charged plate (like charges repel) as possible. this initially sends the particle on the path of le... |
[
"If someone has a cervical or thoracic spinal cord injury with total loss of motor function below the lesion but some intact sensation, will they still have motor reflex arcs below the level of injury?"
] | [
false
] | [deleted] | [
"From what I recall from school, reflex arcs only occur in the spinal cord. There is no/minimal brain involvement, that's why it's a reflex and not a voluntary motion. If you have a cord transection at any level, you will have no reflexes below that point because there is no activation of the spinal cord. I'm sure ... | [
"When you say total loss of motor function, I assume you mean total loss of ",
" motor function. Otherwise there would be no reflexes since they involve motor function.\nVoluntary motor function requires an intact signal path from the brain to the skeletal muscle. Somatic motor reflexes are not voluntary, and do ... | [
"IIRC, reflex arcs by definition do not project to the brain: there is sensory input from an organ, the afferent fibers carry it to the spinal cord, and from there the signal is immediately relayed back to the effector organ.",
"For example, the bulbocavernosus reflex (anal sphincter contraction after stimulation... |
[
"I was staring out onto a lake, and the reflection of the moon on it, and there was just a big black line going horizontally through the reflection, like a shadow... what causes this?"
] | [
false
] | null | [
"Were there any trees behind you?"
] | [
"Could it have been a log or something in the water? Did it move with the moon over the course of hours as the moon moved in the sky?"
] | [
"I know dude, i was just kidding!"
] |
[
"There is a lot of talks recently about herd immunity. However, I read that smallpox just killed 400'000 people/year before the vaccine, even with strategies like inoculation. Why natural herd immunity didn' work? Why would the novel coronavirus be any different?"
] | [
false
] | null | [
"I think the gap in your understanding is that herd immunity doesn't stop the disease existing, it just represents the mathematical steady-state of the disease in the human population. Keeping that steady state requires continual new infections.",
"Estimates of smallpox r0 are 3.5-6, so we are looking at somethin... | [
"30% was the rate for the entire population. For the older population it was closer to 70%. In some populations it was over 90%. People compare the coronavirus pandemic to things like the black death and smallpox have no appreciation for how lethal acute illness was in the not so distant past."
] | [
"Except that there is a widespread and highly effective vaccine for rabies."
] |
[
"Why do physical bodies attract with a force proportional to their mass?"
] | [
false
] | I always thought that nobody knows for sure why physical bodies attract with a force proportional to their mass. However, they know a vast amount about these observable proportions. Am I wrong? | [
"Because we live in a universe with gravity."
] | [
"Each subatomic particle curves spacetime a set amount, so an object that consists of more of them would curve spacetime more."
] | [
"right, as well as any additional corrections like binding energies being stored or subtracted from the mass. Fun thought: up and down quarks are 3-5 MeV. Protons are ~950 MeV, but only have 3 quarks. The rest is the binding energy of the proton. Same with the neutron. The electron is only about 0.5 MeV, so the bul... |
[
"Reading or listening, which is more difficult?"
] | [
false
] | null | [
"I don't have too much to add to gwyner's and GretalRabbit's responses. The question is incredibly hard to answer in a straightforward way. There are a thousand factors that can affect the perceived difficulty of a task, and defining and measuring \"difficulty\" objectively is quite, well, difficult. ",
"Here ... | [
"I'm not sure of any scientific details/reasons, but from experience different people find listening easier, while others find reading easier. This is particularly relevent to learning styles- I learn better from reading and writing, whilst my sister loves to listen and talk about things to learn."
] | [
"I'm not a linguist but I am a polyglot (IANALBIAMAP?) Most of the time you will find listening to be more difficult to learn, unless you've grown up listening to a language all your life and just need to become literate. ",
"As reading will go as slow as you want it to and you can use a dictionary to augment yo... |
[
"Why do boomerangs come back when you throw them ?"
] | [
false
] | [deleted] | [
"when it is spinning the blades on one side are spinning into the wind (not really wind, but the oncoming airstream) and thus creating more lift, compared to the blades on the other side which are going with the wind. More lift on one side of the boomerang causes the entire object to tilt and turn, thus the boomer... | [
"do you read ",
"this",
" first?"
] | [
"I did, but there seems to be no explanation both detailed and not too hard to understand."
] |
[
"How do mixed drinks retain an even distribution, even after being undisturbed for prolonged periods of time?"
] | [
false
] | null | [
"It becomes a solution , of miscible substances. Water, alcohol, sugar, are all soluble.\n",
"http://en.wikipedia.org/wiki/Solution"
] | [
"Read the article about solutions. That explains it."
] | [
"Read the article about solutions. That explains it."
] |
[
"How would a 'sonic boom' affect a human in free-fall?"
] | [
false
] | A man is going to attempt to break the speed of sound by free-falling from very great height. If he breaks the speed of sound will there be a "sonic boom", and how will it affect him? | [
"I actually had this discussion with someone earlier today. Their explanation (which may turn out to be wrong, none of us are experts) was that this fellow only stands a chance at breaking the sound barrier due to the altitude he is jumping from and the fact that the air is considerably thinner that far up. As he... | [
"A sonic boom is simply the sound an observer hears from the supersonic N-wave that is generated from an object traveling at supersonic speed. Felix Baumgartner will break the speed of sound and thus he will generate supersonic shock-waves, but since he is breaking the speed of sound so high up and in such thin air... | [
"I think his question was about slowing down from 700 mph not the effect of going said speed. He will be slowed down with multiple/ separate chutes. He will pop a smaller chute early to slow him down enough to pop a larger/main parachute that will allow him to land"
] |
[
"Neutron-Neutron strong nuclear force?"
] | [
false
] | If there is no electrostatic repulsion between neutrons, why do we not find large groups of neutrons in a stable configuration? | [
"Ultimately because protons are less massive than neutrons, so if a many-neutron system can reduce its mass through beta decay, it will. Apparently a ",
"two neutron state",
" has been observed, that decays in 10",
" seconds.",
"However, in neutron stars the massive gravitational potential overwhelms the in... | [
"To clarify:",
"If the dineutron lifetime is 10",
" sec, it is not due to the decay of a neutron which has a 15 minute lifetime. Lifetimes this short are due to the strong interactions, indicating that the dineutron is a metastable state (slightly unbound)."
] | [
"Amazing. Thanks for the informative (and fast) reply."
] |
[
"Is global warming accelerated by roads, agriculture and buildings?"
] | [
false
] | Roads are black and reflect heat, trees are gone replaced with a field, buildings with black tops, etc... What used to be large expanses of trees are now large farming fields, roads and buildings. Can't this be the source of global warming? Or to what extent is it contributing to it? Thanks for your answers... | [
"Yes and no. Recent studies on Land use affecting climate change have proposed that most (if not all) of the observed climatological variation can be explained by land use changes over time (instead of CO2). It's not a widely accepted view in the scientific community though. In any case, Land use changes are mor... | [
"Actually, the color of roads in particular is one thing we can change to help with global warming",
".",
"So it is not a source for global warming, but it isn't helping."
] | [
"No, because developed area on the Earth is extremely small compared to the amount of un-developed land. And then after that you have to consider the amount of the earth's surface that is water."
] |
[
"Making parabolic mirror setup for solar heating: what is the science behind mirrors and reflection?"
] | [
false
] | I want a series of mirrors to reflect light onto a single point (or multiple points). I will eventually have them computer controlled. . What mirrors should be used for reflecting light onto a single point? Convex? Concave? What is focal length and how will it be important? How can I determine the maximum temperature a... | [
"You need a concave ",
"parabola",
". Satellite dishes are already roughly this shape. A hanging chain or rope will approximate the right curve, but it's actually ",
"catenary curve",
".",
"The temperature depends on too many things to be reliably calculable. What's easiest to calculate is the multiplier ... | [
"For an ideal mirror, the focal length identifies the position where all the light converges into a point. So for an ideal mirror it should be 0 diameter.",
"For a non-ideal case, I think it depends entirely on how well and how accurately you can manufacture the object. I don't know of any way to calculate the ... | [
"If you get a satellite dish, you can use lots of small flat mirrors.",
"See ",
"http://www.cockeyed.com/incredible/solardish/dish01.shtml",
"and",
"http://www.dailymail.co.uk/sciencetech/article-1351935/Eric-Jacqmain-invented-Death-ray-dish-intensity-5-000-suns.html"
] |
[
"How do random number generators work?"
] | [
false
] | [deleted] | [
"Most computers use a function of the current time, a seed and then a modulus to generate the desired result. A computer cannot by itself generate truly random values.",
"Cryptography software often prompts the user to move the mouse or push the keyboard randomly to generate more randomness into the function. For... | [
"I am in a cryptography class so I hope i can answer this one!!",
"Truly random number generators exist in two forms: hardware number generators and software number generators. Intel's hardware random number generator observes temperature values on different transistors. Software random number generators might us... | [
"Usually computers use something called pseudo random number generators. The word pseudo is often omitted too but it signifies the fact that the numbers aren't in the strictest sense random. However, for many practical purposes they'll do just fine. There are numerous different methods of doing this. Some produce m... |
[
"[Biology/Dendrology/Plant Taxonomy] Do trees need the seasons to thrive?"
] | [
false
] | Do trees need the seasons to ? For example, could they be kept in-doors, climate controlled, with optimal conditions year-round, and be expected to have unimpeded growth (no tree rings)? Or do they need the lower sunlight, colder temperatures, dryer soil, etc to "hibernate" or "harden" themselves? Will they still hiber... | [
"Fruit trees require \"chill time\" --- a certain number of hours where the tree above freezing but below about 10°C --- or they won't set fruit. The amount of time required varies with the species and cultivar. It's a big part of why you can only grow certain fruits in certain climates. If they don't get sufficien... | [
"Depends on the species.",
"Tropical plants have adapted/evolved to not really need it, same with many gymnosperms and their anti-freeze sap. The basis is that there is lower light in the winter. Also the higher risk of freezing causing air bubbles which is VERY bad for the tubelike cells in a tree. Block enough ... | [
"Sorry for the late reply, but thank you for sharing this.",
"So the hibernation of trees is directly tied to their evolution... Meaning that, similar to the way that some fruiting trees are selected for their more desirable fruit, we could cultivate some non-native trees to grow in colder/hotter environments wit... |
[
"Is there really a risk of data theft via RFID?"
] | [
false
] | A family member recently told me they have bought foil-lined wallets for their passports and credit cards to prevent against data theft via RFID scanning. I initially wrote this off as crazy paranoia. However, there's actually a fair amount of information on the subject, but I don't know if that's the whole picture or ... | [
"Another option on the personal level is to simply destroy the RFID chip (hit it with a hammer, or stick your passport in the microwave for a few seconds). Your passport will still function as a passport even without the chip."
] | [
"Bear in mind that in the US, ",
"\"whoever falsely makes, forges, counterfeits, ",
" any passport or instrument purporting to be a passport\" can be sentenced to up to 10 years in prison.",
" Although they'd have a hard time proving the damage was intentional."
] | [
"Chip readers don't use the security numbers on the back."
] |
[
"How is Li-Fi faster than Wi-Fi if radio waves and light travel at the same speed?"
] | [
false
] | null | [
"The light waves don't travel faster than radio waves. Light is much higher in frequency. Therefore higher bandwidth modulation can be used therefore higher data rates. Also you don't have to worry about too much interference frog neighbour's systems (inside your house or apartment) since the light waves would be ... | [
"You are confusing data rate and delay. The signals will arrive at the same time, but the amount of data they carry can be different.",
"In general Li-Fi has a much wider bandwidth it can use due to how directional it is. Bandwidth directly determines the maximum signalling rate before ",
"ISI",
" occurs. Thi... | [
"The capacity to carry data is greater with higher frequencies, all else being equal. Light has a higher frequency than radio waves, so light has a greater capacity for data in a given time frame.",
"\nThink of a light switch you can only turn on and back off once every second. How long would it take you to sen... |
[
"How does a cell \"know\" what type of cell it's supposed to be, if DNA contains all the genetic information for the entire organism? Can cells (other than stem cells) be tricked into becoming a different type somehow?"
] | [
false
] | For instance, could I somehow induce a liver cell to become a kidney cell? | [
"During differentiation, asymmetric cell division causes certain gene products (RNA and peptides) to be localized at one pole of a dividing cell, so that only one cell \"inherits\" them. These in turn influence the gene expression profile of the cell they're in. So, for example, if one cell inherits a gene produc... | [
"This was actually the subject of some recent Nobel-prize winning work. See here: ",
"http://en.wikipedia.org/wiki/Induced_pluripotent_stem_cell",
"Basically, this guy named Yamanaka discovered that if you express these four genes (the so-called \"Yamanaka factors\"), Oct4 (Pou5f1), Sox2, cMyc, and Klf4, in a ... | [
"There's a couple things you want to look at. Of course you want to look at the wiki page on cell differentiation. But you should also check out Boolean networks, which are supposed to be a model of gene regulatory networks. The attractors in the network activation space can be thought of as specific cell types.",
... |
[
"Can our organs feel 'pain'?"
] | [
false
] | Do we have pain receptors on our organs or rather just our skin? | [
"For the lungs: the only pain receptors are on the outside. This means that if you get stabbed - you feel pain 1st as the skin is cut, again when the pleura that lines the ribs on the inside is cut, and again when the lung itself is punctured. However, if we snake a tube through the mouth or nose and down the th... | [
"Not all our major organs are sensitive to pain, however some are, but we do have pain receptors in other places than just the skin.It can be very difficult to find painkillers for Visceral pain.",
"Unrelated but the skin is an organ."
] | [
"Sorry - don't know enough to answer on the types of pain receptors. But from a what you feel standpoint - when we biopsy the lungs or drain fluid from around the lung - we have to make sure and get numbing medication (lidocaine) on or in each layer as we slowly advance the needle. I only do the \"drain the fluid... |
[
"If its true that prehistoric animals and insects were able to grow to such larger sizes because of larger oxygen levels in our atmosphere..."
] | [
false
] | then if we hatched some eggs in a oxygen controlled chamber would be be able to grow giant spiders, rats, dogs, etc...? Or what other conditions would have to be in place to do such a thing? And would that also increase the size of humans? | [
"This exact experiment was carried out last year!",
"They were able to grow dragonflies 15% larger than normal (although that is nowhere near the 70 cm wingspan giant dragonflies of the past had). The current thinking is that insects are particularly sensitive to atmospheric oxygen levels because of their differi... | [
"AFAIK this enlargement due to an oxygen-rich atmsophere has only been proposed for insects."
] | [
"Unfortunately, I don't have a good answer except to suggest that ",
"large size had something to do with thermoregulation",
": larger bodies retain heat better. I should also point out that the populations were not dominated by large creatures; there were many small (and even tiny) dinosaurs."
] |
[
"Does the act of your nose becoming blocked by congestion have a biological benefit, or is it simply a side-effect of the congestion itself?"
] | [
false
] | To expand and clarify, is there some reason why causing one or both nostrils to become completely obstructed, thus preventing them from intaking air, have any benefit to the fighting of infection? Or is the stuffiness merely an uncomfortable side-effect to being congested and infected. | [
"When you have a cold your nose doesn't get blocked by mucus and snot, it's caused by the blood vessels in your nose becoming inflamed as a response to to viral infection. Your body expands your blood vessels to enable transport of stuff needed to fight the infection to happen more efficiently. "
] | [
"A little bit of both. ",
"Mucus is typically a thin, clearish fluid moved by cilia in the nose towards the back of your throat. During cold weather, the cilia doesn't work as well leading to congestion or runny noses. Mucus also contains antimicrobial properties, so producing more when you sick will help trap mo... | [
"You're thinking about it the wrong way round, usually the snot in your nose doesn't cause it to get blocked because your sinuses are nice and wide, it's only when you have the inflammation that the snot can complete the blockage. "
] |
[
"Why do vacant orbitals become higher in energy if you add electrons to them?"
] | [
false
] | I know that when applying the Aufbau principle, you fill up the 4s orbital before the 3d, but when forming ions, electrons are removed from the 4s orbital first, meaning somewhere along the line, the 4s orbital has increased in energy, to a point where it is higher than the 3d orbital. Why does this happen? | [
"The reason this occurs is due to shielding, and the factors that influence how different orbitals shield each other. ",
", meaning that the 3s and 3p shells have been filled and you have one electron that you can either place into either the 4s or 3d, the 4s will always be lower in energy. The reason is that t... | [
"Loving the \"usually...\", damn electrons. But thank you! This is what I was looking for!"
] | [
"I think you confused a couple of things here.",
"In the title you asked, what happens when an electron is added, however in your details you asked about positive ions (where one or more electrons have been removed).",
"So let me attempt to clarify some of this: The energy of an atom can be increased if they ab... |
[
"Are we still immune to eradicated diseases like smallpox or would another pandemic start if the disease re-emerges?"
] | [
false
] | [deleted] | [
"While some of us have been around long enough to have been vaccinated against smallpox as children, ",
"routine vaccination was discontinued in 1971",
". Some groups of military personnel are still currently vaccinated against smallpox, but by no means all. Unfortunately even for those who have been vaccinated... | [
"Smallpox is one of the oldest viruses known to man. ",
"Records of smallpox go back at least 3,500 years, but it's believe to have emerged around 10,000 years ago",
". By the time of its eradication, it was a human-specific pathogen with no other animal reservoirs, which is in fact what made its eradication po... | [
"Follow up question: Approximately how long (from a lower range of say 10% chance to an upper range of say 90% chance (e.g. 10% chance it would take 200 years, 90% chance it would take 1800 years)) would it take humans, given current environmental conditions, to evolve to the point that the current smallpox stocks ... |
[
"Are there any toothpastes that are not abrasive? Are mouthwashes abrasive?"
] | [
false
] | I base this question on the 2 previous threads that really were left inconclusive. | [
"abrasive implies there is some sort of grit mixed in to aid in the mechanical removal of plaque. so mouthwash is definitely not abrasive. there are a lot of toothpastes that are gel, and those do not contain grit, instead they rely entirely on the brush for mechanical removal of plaque, though they are not technic... | [
"Would you by any chance know the name of a gel brand?"
] | [
"Close up works quite well. ",
"Although, i prefer a my toothpaste a little abrasive or corrosive. I mix hydrogen peroxide and baking powder on my toothbrush once every three weeks to get the stain out while using pronamel on a daily basis."
] |
[
"Would it be possible to power a power plant by using a giant magnifying glass to boil the water?"
] | [
false
] | Sure it would be extremely unreliable, but wouldn't it work? How big of a magnifying glass would you need? I feel like it would totally would be worth it to get essentially free energy. Edit: Thanks to Chivalric for the appropriate article. | [
"Those exist, in a form. ",
"Here",
" and ",
"here",
" are examples. They aren't exactly magnifying glasses, but they use a series of mirrors to concentrate sunlight and heat oil."
] | [
"It's called 'solar-thermal' because it depends on heat, and they use mirrors (\"non-focusing optics\") because they can concentrate the power to a single point, rather than an image of the disc, or a spectrum depending on frequency. Also, they weigh less. Moving parts and mechanics are involved, so they are gene... | [
"I assume you aren't referring to photovoltaics? I don't know of any solar panels that work as you've described. "
] |
[
"Can you charge a capacitor to a higher voltage than it's power supply?"
] | [
false
] | I only know the basics on circuits, just curious. | [
"Yes, but only with alternating current (AC).",
"You can make a resonant circuit by wiring a capacitor and inductor together in series. The circuit will resonate at an angular frequency given by",
"omega_0 = 1 / sqrt(LC)",
"Suppose we drive this circuit with a voltage drive given by",
"V sin(omega t)",
"I... | [
"Sure. To me switch=AC, but words are only words."
] | [
"Yes, but only with alternating current (AC).",
"Well, it depends on what you mean by AC. One can definitely turn a lower DC voltage into a higher DC voltage by means of a ",
"boost converter.",
"The thing about those is that one needs a switch that turns on and off at a relatively high speed, so inside the ... |
[
"Does a Mayfly, which only lives a day, evolve fast than a human?"
] | [
false
] | This might be really stupid but to me it makes sense, kind of. Evolution is about survival of the fittest right, so the more generations you have the faster changes take place and the weak are weeded out. | [
"Yes. Generation time has a significant effect on how fast a species evolves. Here's an article about the effect on molecular evolution in bacteria (which can evolve even faster than mayflies):",
"http://onlinelibrary.wiley.com/doi/10.1111/evo.12597/abstract"
] | [
"Also please remember that generation time in mayflies is much longer than one day. They are ",
" for a day, but live as nymphs under water for at least a year before that. They spend the grand majority of their lives under water."
] | [
"It's a common misconception that a mayfly (Ephemeroptera) only lives one day. They have four phases: Egg, nymph, subimago and imago. Most of their life is spent as a nymph under water. They live for up to a year before they emerge to the surface and \"hatch\" into an adult subimago. After hanging out for a bit, th... |
[
"If we're in the Milky Way, how do we take pictures of it?"
] | [
false
] | If a galaxy contains billions and billions of stars, and we're inside it, then isn't every star we see at night "the milky way"? What are we actually seeing when we see of a picture of the Milky Way? Some beautiful cluster of stars elsewhere in our galaxy? | [
"All the ",
"head on pictures",
" of the milkyway are not of our galaxy. They are either simulations/Pc generated pictures or pictures of other galaxies. ",
"We can however see the milkyway from its side like this: ",
"pic"
] | [
"Wow, thanks for that second pic. I guess it makes sense. It just seems weird, like taking a picture from the back seat and saying \"look, my car!\" lol"
] | [
"When we take a \"picture\" of the milky way, it is really just a computer generated reconstruction of the milky way. We take pictures in all directions from the earth and use these images to construct a 3d model of what the milky way actually looks like."
] |
[
"Are there any truly stationary points in the universe?"
] | [
false
] | As I sit here I'm not really stationary, I'm on a planet in a solar system in a galaxy. On top of that, space itself is expanding. Does anything stand still? | [
"Relativity tells us that your question doesn't really have meaning. What I mean is that in Physics you don't ever ask what something's velocity is, you ask what the velocity is ",
". This is what is known as a frame of reference. ",
"So to answer your question, there are definitely things in the universe that ... | [
"This revelation, that there is no special, stationary reference frame is what lead Einstein to develop special relativity (bit of a simplification). The assumption that there existed a single, stationary reference frame was fairly ubiquitous in physics for a long time. Many believed it was the reference frame in w... | [
"If you think about it, everything in the universe is stationary with respect to itself"
] |
[
"What's the difference between connecting to a network with a Static IP and adding a static ARP cache entry?"
] | [
false
] | Do they do the same thing? How do the consequences / behavior from the computer to router differ? | [
"Certainly not the same thing. You have to look at what actually happens when computers communicate.",
"Let's say you have several computers in a shared medium. The network cards only know about Ethernet, they don't deal with IP. On Ethernet there's only the local segment and devices are addressed by MAC address... | [
"ARP is used to communicate locally--- i.e. on the same network. ARP is actually a protocol used to learn hardware addresses called 'MAC' addresses. MAC is a hardware address, while IP is a logical address (MAC is burned into your network interface card, while IP is just assigned by you or whatever your preferred D... | [
"Ah that makes sense, thank you!"
] |
[
"What's the slowest a commercial airplane can fly and still maintain altitude?"
] | [
false
] | [deleted] | [
"Like Brent said, it's dependent on a large number of factors, most particularly what kind of plane you're talking about and the operating conditions. But from Googling around, I found that a lightly loaded 737 in level flight and flaps fully extended has a stall speed of approximately 100-110 kts (115-125 mph). As... | [
"That would depend on a host of things, the first of which being the question ",
" commercial plane.",
"Each and every airplane has a certain curve of Lift Coefficient versus Angle of Attack. The lift coefficient multiplied by the air density multiplied by the airspeed squared multiplied by the wing area yields... | [
"Depends on the airplane, as breintje pointed out. Some small 2-4 seater planes can fly at about 30 mph or less, but I don't think that's what you're talking about. Big jet liners need to go much faster.",
"Also depends on the altitude: The higher the airplane is off the ground, the faster it needs to go to ma... |
[
"If light has energy, it has momentum. But if it has momentum doesnt that mean it also has mass?"
] | [
false
] | If light has Energy (E) then according to Einstein it also has Momentum (E²=(mc²)²+(pc)²) but if it has Momentum (p) it also has mass (P=mv). I dont understand. How can something have momentum but no mass? Is p=mv just outdated and a simple formula taught for its ease and can only apply to classical objects? | [
"As you surmised, p = mv only applies to classical motion of objects well below the speed of light."
] | [
"You gave the essential expression in your post.",
"This result leads to p=E/c for an object moving at speed c (which means a massless object) and p=mv/sqrt{1-v",
"/c",
"} for an object with speed less than c (which means an object with non-zero mass)."
] | [
"It already is: ",
"http://www.reddit.com/r/sciencefaqs/comments/g3qlc/is_light_massless_why_is_it_affected_by_gravity/"
] |
[
"A question about the Hodgkin-Huxley model"
] | [
false
] | These science rockstars are definitely amongst my all-time heroes. I was going over their equations, and H&H used the variables m,n, and h to describes the dynamics of voltage gated channels. I was wondering, Why are m and n raised to powers, while h is not? I understand that m and n deal with channel activation and h ... | [
"Cool, thanks. ",
"Yeah I should look at their papers. Physics is still kinda scary to me, but I've been getting more comfortable. Thanks for everything =)"
] | [
"These exponents were determined by fitting to the experimental data.",
"The interpretation is that there are 3 'm' gates in the protein, which all need to be open in order for the channel to be considered open, but only one 'h' gate which inactivates the channel when it closes.",
"If at some voltage, in steady... | [
"They published 5 papers in the journal of physiology in 1952 which would go over their process of discovery.",
"Membrane potentials were certainly well known about at that time, the first estimation of the diastolic membrane potential was by Bernstien in 1902.",
"The best source I have on this:",
"http://www... |
[
"While walking through a Pennsylvania forest, I saw a rock the size of a car. How long has it been sitting there, and where was it before that?"
] | [
false
] | [deleted] | [
"That's definitely not enough information to give anything close to a definitive answer, but we can speculate a bit. Assuming you did not see said car-sized rock directly adjacent to elevated topography with exposures of similar bedrock (if you did, then it probably is sourced from said exposures and moved through ... | [
"I don't know if I'm being helpful or pedantic -- maybe both -- but here's a rough translation from Geologist:",
"If it's near a hill, it probably slid down the hill. Otherwise, it probably got pushed there by a glacier around 25,000 years ago. Hard to say how far, though."
] | [
"This area (PA) is known for its glacial debris.",
"To answer the OP where it came from, maybe Canada!"
] |
[
"Do Xrays, UV, IR, Microwave, and Radio waves all travel at the same speed as Visible Light?"
] | [
false
] | I understand that they are not separate entities per se, but rather different wavelengths of the electromagnetic spectrum, but do the difference in wavelenths affect the speed of travel? | [
"In vacuum they all travel at the same speed.",
"In a medium the speed can and does depend on wavelength."
] | [
"When talking waves, Speed = Wavelength x Frequency. ",
"All of these waves are electromagnetic radiation, so in a vacuum they will all travel the same speed: the speed of light, c. So this equation looks like :",
"c = λ * f",
"where c = speed of light, λ = wavelength, and f = frequency.",
"As either the... | [
"It's also important to mention here that even should light have such variations, c is a bit of a universal constant that we just happened to discover as the speed of ",
" first. More accurately we could call it a unit conversion factor between lengths measured on a ruler and lengths measured on a clock (time). L... |
[
"Is it possible to completely saturate a contained area with light?"
] | [
false
] | Here's a theoretical question that was posed to me the other night. Let's say you have a room with smooth, connected sides such that no light can escape. Then let's say that you continue to fill the room with light. Is there a point when the room becomes saturated with light such that no more light could be added to th... | [
"no. light being bosonic in nature, do not obey pauli's exclusion principle, so any number of photons can occupy the same space."
] | [
"Light does exert pressure, which is the principle used for solar sails. There is not much pressure, though, and LASERs blow things up by heat, sometimes with mechanical effects from the heated bit of the object vaporizing."
] | [
"You are describing a photon gas. It has pressure and will eventually blow up your room. If it is a very strong room, it will probably turn into a black hole at some point.",
"But I guess the answer you are looking for is \"no\"."
] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.