title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"How does a cold make us produce more snot and or mucus?"
] | [
false
] | [deleted] | [
"The short answer is cytokines.",
"The longer answer is that the immune system releases IL-13 and IL-6. Macrophages that are in the infected area pump out a LOT of IL-6 (T cells make some as well) which causes goblet cells to increase mucus production.",
"Th2 cells will produce IL-13 which has the same effect. ... | [
"It flushes viruses, bacteria, and allergens out of the body. Even before flushing them out, it keeps them away from tissue surfaces and makes attachment and entry harder. Some bacteria have mucinase that overcomes this. "
] | [
"Thanks!"
] |
[
"Did we always know that electricity was a physical phenomenon? If not, when did we find out?"
] | [
false
] | null | [
"I would like to encourage more history of science questions here. However, if you don't get an answer, try ",
"/r/askhistorians",
" or ",
"/r/historyofscience"
] | [
"As I understand it, ancient cultures such as the Greeks knew that static electricity was a thing, mainly due to the shocks produced when rubbing amber and fur together, but it wasn't until the 1600s when we really started to begin differentiating and classifying different electrical phenomena and began understandi... | [
"Thanks, I'll wait and repost in the morning on one or both of those subs."
] |
[
"(Repost) from r/pics. Bone cancer"
] | [
false
] | Why does the body do this to itself? What causes it? | [
"It's likely this is osteosarcoma, the most common primary malignant bone forming tumor. Although usually found in metaphyseal region of long bone it can occasionally occur here in the skull. Bone is laid down haphazardly in the periosteum, the outer layer of bone. This periosteal reaction in osteosarcoma is charac... | [
"Is this as painful as I imagine it to be?"
] | [
"Yes. Pain is also one of the most common symptoms of osteosarcomas."
] |
[
"Is Chess really that infinite?"
] | [
false
] | There are a number of quotes flying around the internet (and indeed recently on my favorite show "Person of interest") indicating that the number of potential games of chess is virtually infinite. My Question is simply: How many possible games of chess are there? And, what does that number mean? (i.e. grains of sand on... | [
"On mobile - it shows up as 1043. It's actually 10 raised to the 43rd. ",
":) just to clear up any confusion. "
] | [
"Shannon has estimated the number of possible legal ",
" to be about 10",
". The number of legal ",
" is quite a bit higher, estimated by Littlewood and Hardy to be around 10",
" (commonly cited as 10",
" perhaps due to a misprint). This number is so large that it can't really be compared with anything th... | [
"Bobby Fischer often said he was bored of normal chess because the game positions and strategies could be too easily memorized so that play on even the highest level was more about remembering the positions from prior experience and proceeding rather than having to rely on pure analytic thought and deriving the bes... |
[
"The Paradigm Shift!"
] | [
false
] | Paradigm shifts occur when substantiating, and validated, evidence has been accumulated to a degree that overcomes skepticism. New theories are normally considered fringe science until they reach this point, and are discouraged by journal editors and those who control scientific funding. My thoughts are that paradigm s... | [
"Because fringe theories fail the first requirement, which is: reproducing the known experimental results. That's why they're fringe. "
] | [
"Why isn't this practical?",
"Because in the ",
" majority of cases, 'fringe' science is a waste of time and money because it's wrong. ",
"Big, game-changing discoveries are exciting, but the number of these occurances in recent scientific history can probably be counted without taking your shoes off."
] | [
"So we are too close to understanding ",
" for fringe science investment to be viable because the likelihood of a fringe theory finding validation is too low?"
] |
[
"I drop an object from a tower at the equator. In the direction oft earth's rotation, does the object land in front of, exactly at, or behindert the foot of the tower?"
] | [
false
] | null | [
"Due to the Coriolis force, the object is deflected slightly in the Westward direction."
] | [
"westward? Are you sure? Earth moves west to east, shouldn't it be eastward?"
] | [
"The equation for the Coriolis force is given ",
"here",
". If you evaluate the cross product of the Earth angular velocity and the velocity of a downward-moving object at the equator, you get a vector that points West."
] |
[
"What properties of a hexagon make it such a 'natural' shape?"
] | [
false
] | The hexagon is a pretty common shape in nature, with slime moulds, bee hives, crystal close packed structures, etc. almost as common as the natural logarithm. Why? | [
"Imagine dots aligned that way:",
". . . .\n\n . . . .\n\n. . . .\n",
"Now imagine a circle growing out of each of these dots at the exact same speed (or almost). Imagine that when they touch another circle they stop growing in that direction. So the shape keeps growing but keeps hitting oth... | [
"If you want to build a container with a special volume, an sphere has the lowest surface/Volume ratio and would be the best choice. Eggs for example are near orb shaped.\nBut if you need many containers, you could use the already existing walls of the first container to add the 2nd container directly to the first ... | [
"If you want to pack the greatest number of circles in a 2D plane, you must use a hexagonal lattice (this is a mathematical fact). ",
"Just like circles are so common because they are the shape that minimizes circumference and maximizes area, hexagons are common because they create a pattern that maximizes the nu... |
[
"How can a photon be \"massless\"?"
] | [
false
] | I've taken physical chemistry (quantum mechanics) and something I never got was how light was considered just a "wave". I understand in quantum mechanics that this is false since light exhibits particle and wavelike properties, but how can a photon/light be massless? Wouldn't it not be a particle then or even exist sin... | [
"Wouldn't it not be a particle then or even exist since it has no mass?",
"No, there is no need for a particle to have mass. Humans are used to imagining mass as being made of \"stuff\", i.e. some kind of substance that exists and takes up space, and indeed this is a very useful picture in the real world. However... | [
"So my issue here is I'm looking at quantum mechanics from a classical mechanics point of view, which is counterintuitive, since it's quantum. In that case would you happen to know why particles produce wavelike behaviors? Thanks by the way. "
] | [
"Can you elaborate a bit on what you mean by \"why particles produce wavelike behaviors\"? The fact simply is that at the level of quantum mechanics there is no such thing as solid point particles or classical waves as we understand them in the classical world. Instead, everything exhibits both particle-like and wa... |
[
"Is there a simple test to differentiate between copper and aluminum braided wire?"
] | [
false
] | [deleted] | [
"Copper looks copper-colored. Aluminum looks silver. There could be a coating on the wire, but if it's copper the core should look like copper. ",
"You could try dissolving some in sulfuric acid or nitric acid. If it turns blue, it's from copper salts. Aluminum salts are colorless, typically. "
] | [
"Can be difficult to tell on small diameter wire. "
] | [
"Melt a piece. Using a neutral flame copper will just melt while aluminum will slag. "
] |
[
"Are antibiotic resistant bacteria found in nature?"
] | [
false
] | So I was watching Grey's Anatomy tonight, and in the episode one of the doctors has an infection on her leg from being stranded in the wild for 4 days, and later the other doctors are talking about how the infection is resistant to Vancomycin. Obviously this television show isn't too realistic with the details, but as ... | [
"Remember where antibiotics come from... fungi produce them in nature to fend off bacteria. Antibiotic resistance didn't appear ",
" when we started using them to fight infections in humans - many of those resistance genes were already around in the bugs that compete with fungi in their natural environment.",
"... | [
"I'd add that it's the modern era, in which global travel is a reality. We take native samples from all over, geographically, so you can even find very specific types of resistance in environments where it might be a surprise otherwise (e.g., vancomycin resistance in a sample from a rural Sami encampment in norther... | [
"Antibiotics are also often produced by bacteria themselves. For example, kanamycin is produced by ",
" and erythromycin from ",
". It is believed that antibiotic resistance developed ages ago simultaneously with the emergence of bacteria-secreted antibiotics as sort of an \"arms race\" for competing bacteria s... |
[
"How many fundamental fields are there?"
] | [
false
] | null | [
"It's a little bit of a question as to how you count things, but here is a list of the fundamental fields:",
"Leptons:",
"electron, muon, tau",
"electron neutrino, muon neutrino, tau neutrino",
"Quarks:",
"up, charm, top quarks",
"down, strange, bottom quarks",
"Others:",
"Higgs",
"photon",
"W",... | [
"To be precise, the basic field in general relativity is the metric (the object that determines how space is shaped at any point). If gravity were to be quantized like the other forces, it is quantizing the metric that would give rise to the graviton."
] | [
"Is it the metric that's ",
" gravitational field in GR, or the Einstein tensor?"
] |
[
"Does light really make one lightyear per year, even though space is expanding?"
] | [
false
] | Let's say we had a star 1 mio lightyears away. While its light travels to us, the space itself in between is expanding, so the light has to travel a longer distance. Technically, the light therefore should take more than 1 mio years to reach us, even if the star was exactly 1 mio lightyears away originally. Am i correc... | [
"It's a very interesting question, and harder than you think. So I try explain, in local universe, low redshift, 1lyr is exactly the time the light make in one year. ",
"In cosmology we are some types of meansure distance, the comoving distance, that's depends on the grid of space time so the metric of space time... | [
"The distance traveled in the year by a photon remains constant while the matter taking up “space” is expanding.",
"It's not the matter that is expanding (that's not expanding), but spacetime (seen in the FLRW metric)."
] | [
"The distance traveled in the year by a photon remains constant while the matter taking up “space” is expanding.",
"It's not the matter that is expanding (that's not expanding), but spacetime (seen in the FLRW metric)."
] |
[
"How come bodybuilders need to be infinitely precise with the types and amounts of food they eat, yet my horses just munch on some hay and are physical specimens?"
] | [
false
] | Have we just weeded out all the fat, slow, weak horses after thousands of years of domestication, or what causes this difference in how our bodies utilize resources? | [
"Well what about the fact that horse diets are so monotone? I've been around a lot of horses and never ran in to any that didn't mainly eat hay and then occasionally had a treat or some kind of oats. How does this one bland form of nutrients sustain their entire massive bodies while (as I understand it) it's very... | [
"There are many different ways to answer this. But ill give it my best shot. \nDepending on breed, level of exercise and work along with soundness of their legs and hooves there is a difference between a fat horse and a muscular horse. Yes there are still fat, slow and weak horses mostly caused by injury, issues at... | [
"....Well there are many different versions of feed for different horses. Some high spirited horses need feed with little sugar, no corn, molasses, or alfalfa meal which gives them what nutrients they need without the \"hyper-ness\" Its kind of like a sugar high, alot of racehorses are like this. Thoroughbreds, War... |
[
"If every multicellular life form suddenly disappeared, would singled celled life forms eventually re-evolve into multicellular ones again?"
] | [
false
] | null | [
"Probably yes. The removal of multicellular life would not be a \"reset to zero\" event. There is still complex single cellular life, some of which is actually very closely related to multicellular life. A really good example would be baker's yeast.",
"There's at least three origins of multicellularity across euk... | [
"Single cells appeared about a billion years after Earth's formation multicellulars took another 2-3 billion years. The mechanism is still unknown, so it's hard to speculate but since the Earth only has about 1 to 2 billion years left before it becomes uninhabitable the probability is low that multicellulars will e... | [
"Single cells appeared about a billion years after Earth's formation multicellulars took another 2-3 billion years.",
"since the Earth only has about 1 to 2 billion years left before it becomes uninhabitable the probability is low that multicellulars will evolve again.",
"It depends, there is a huge variety of ... |
[
"In formulations of string theory which posit \"extra\" dimensions, are these dimensions considered to be orthogonal to \"normal\" dimensions?"
] | [
false
] | This is all a little over my head. Please help me understand dimensional compactification, and whether, with such compaction, those dimensions are still considered to be orthogonal to "non-compact" dimensions. | [
"Yes, they are. There's not really much to it at all, you don't even have to think of the compactified dimensions as real physical dimensions if you don't want to, you could imagine just that the vibration modes and winding modes in the extra dimensions are like some extra internal quantum numbers that particles ca... | [
"Thanks. I'll check some of those videos later tonite..."
] | [
"A dimension is just a measurement. The number of dimensions something has is the number of measurements required to describe it. To describe where you are in the world, you would need latitude, longitude, and altitude. To add when you were there, you would need to add date/time. Then add the temperature, humidity,... |
[
"Why do pens magically fail to work on some small areas of a piece of paper, yet work fine elsewhere on the same page?"
] | [
false
] | null | [
"To combine the other posts, it's due to a portion of the paper having reduced friction. Friction is necessary for most writing utensils to function. "
] | [
"Combine this, ",
"mjbat7's answer",
" and the notion of how a ",
"ballpoint pen",
" works, and you have a pretty good explanation of the problem: if the ball in the tip of the pen doesn't find enough friction to roll it quickly runs out of ink on the part of its surface that's touching the paper."
] | [
"The Lamy Safari is $35. I believe a 3-pack of Pilot Varsities can be had for around $5 at Wal-Mart."
] |
[
"Where do animals' basic intuitions come from?"
] | [
false
] | I've been watching a lot of Attenborough's nature documentaries recently. Often in the commentary, he says that such or such animal (or plant) adapted to have a certain behavior. For instance, you've got these fascinating capuchins who collect palm nuts; let them dry three days; transport them to the cracking site; cle... | [
"Evolution. The baby turtles that got to the ocean had a better chance of mating, so they had baby turtles that had a tendency to go to the ocean. ",
"The baby mammal that drank more milk grew stronger and had more babies than the ones that didn't get as much milk. "
] | [
"Well with the capuchins they're taught by their parents. Those that don't pick up the necessary skills die. ",
"With things like metamorphosis and migration, it's hormones. ",
"As to how a calf knows immediately to go to the udder, I don't know, but I'd be willing to bet it's based on scent. It probably sme... | [
"I'm no expert by any means, but I would imagine that it's something like the way that you automatically jerk your hand away from a hot stove-top, or a sewing machine begins to stitch when provided power. The makeup and arrangement of neurons in the brains of each of these creatures has evolved over time to trigger... |
[
"While driving today right before a storm was about to take place, all of my car windows and the cars driving around me, immediately fogged up. Explain how this happened, please."
] | [
false
] | [deleted] | [
"Condensation forms when warm, moist air comes in contact with something cold. The air is cooled below its dew point near the surface and so some of the water condenses making fog. Do you know if the condensation was on the inside or outside of your window? Usually in a car what happens is that the air inside the c... | [
"Yes. It was on the outside. I know this because my windshield wipers were effective in removing the condensation."
] | [
"Makes sense then. I'm going with the outside of your car windows were cool, and you drove into a patch of warm humid air."
] |
[
"COVID/Flu transmission: Is \"don't touch your face\" just code for \"don't touch mucous membranes\" or is there more to it?"
] | [
false
] | Much of the public health messaging I see around COVID, Flu, and other common sicknesses emphasizes not touching your face with dirty hands. When I hear that, I hear "don't touch your eyes, the inside of your nose, or your mouth"/your mucous membranes. Is this right or is your cheek genuinely a dangerous place to touch... | [
"What you're observing is the difference between generalized advice and specific advice. There is no direct infection mechanism for SARS-CoV-2 that is deposited on the skin, but you could think of the virus's journey to your mucous membranes as a trip with many stops.",
"You touch a surface that is freshly infect... | [
"Thank you, I figured the answer was something like this and you hit on both points: what you put on your cheek by touching it doesn't necessarily stay there (because you move it later), and it's just more palatable/commonly understood messaging than don't pick your nose/touch mucous membranes."
] | [
"First, most viruses require contact with preferred mucus membranes to infect people: nasal passage, eyes, genitals, digestive track are common. The skin serves as an excellent barrier against viruses.",
"There are some common fomite transmitted diseases: hand foot and mouth (spreads from contact of objects espec... |
[
"The ban of chlorofluorocarbons (CFCs) is known to be the most successful international intervention ever. How did we successfully convince politicians worldwide that CFCs was damaging the ozone layer, but today we are still having a hard time convincing politicians about global warming?"
] | [
false
] | null | [
"Unlike CO2, which is just about unavoidable for any form of combustion, a lot of CFC usage was relatively easy replaced",
"This is really all it comes down to. If CO2 emissions could be easily ended, they would be. Unlike CFCs, the entire world depends on burning fossil fuels in order for civilization to functio... | [
"Unlike CO2, which is just about unavoidable for any form of combustion, a lot of CFC usage was relatively easy replaced",
"This is really all it comes down to. If CO2 emissions could be easily ended, they would be. Unlike CFCs, the entire world depends on burning fossil fuels in order for civilization to functio... | [
"Environmental social scientist here.",
"The TL;DR version is that far, ",
" fewer ",
"paychecks depended upon",
" using CFCs than depend on using fossil fuels.",
"CFCs were only used in a relatively small number of products, and already at the time the environmental damage CFCs cause was identified there... |
[
"If black holes can form because of the Schwartzchild radius, then why did the early universe at all expand?"
] | [
false
] | null | [
"The Big Bang was not all the universe concentrated at a point. As far as we know, at the moment after the Big Bang, the universe was infinite in extent, just as it is now. Energy DENSITY was arbitrarily high EVERYWHERE. This is not the ingredients of a black hole, which is a small region of high energy density ... | [
"The blackhole energy density is defined by the density needed to keep light from escaping. So anywhere with that density is by definition inside a black hole",
"No, things that are solutions to the GR equations within the Schwarzschild metric with radii less than the Schwarzschild radius are by definition blackh... | [
"This is covered in the Ask Science FAQ\n",
"After the big bang, why didn't the universe re-collapse under its own self-gravity?"
] |
[
"Where do we get raw elements from? Ie. Neon, helium."
] | [
false
] | null | [
"There are two ways I can interpret your question: 1. How do elements form in our universe? and 2. Where are pure elements found on Earth?",
"For 1, it depends on which elements we're talking about. Very basic elements like hydrogen and helium were formed in the Big Bang. Some other smaller elements like carbon, ... | [
"Sorry, but I have to correct a few facts in your post.",
"First of all, nucleosynthesis to helium occurred in the first 10 minutes after the big bang. This has been known since George Gamov's work in the 1940s. The timescale is set by the decay of isolated neutrons, and it is easy to derive from this the ratio o... | [
"We thought for awhile that supernovae were the main ways that elements above iron were created, in the past decade or so the general consensus has shifted to thinking that these heavy elements are primarily created through neutron star collisions, although supernovae still contribute.",
"And to expand a little o... |
[
"A blue shirt reflects blue light, a green one reflects green light. Is it possible to make infrared shirts and would they be effective at keeping us cool in summer?"
] | [
false
] | null | [
"That shirt might also be pretty effective at trapping your body heat."
] | [
"Not if it was made of a nice unidirectional metamaterial. Reflects IR from one direction, and lets it pass right through from the other side. Added bonus, turn it inside out for a very effective sweater."
] | [
"Yes and no. The thermal jackets you find in survival kits effectively are designed to reflect IR but keep in mind if you're reflecting it from your body, you're also keeping your body from radiating its own heat. I did the research a while ago but what I can recall, 1/3 - 1/2 of your body's cooling is from radiati... |
[
"Have we observed any EM waves from space that were originally radiated as a non-visible EM wave but redshifted or blueshifted into a wave within our eyes' measure of perception? Or is this even possible?"
] | [
false
] | I have a general idea of how the Doppler effect works in terms of light as well as with the expansion of space. I'm wondering if an infrared or ultraviolet wave could ever cross the "threshold" of visible light due to the Doppler effect. Thanks! | [
"Yes. ",
"You could have looked up and seen this in 2008",
" if you were lucky enough to do so at the right time. The light you would have seen did not start out as visible light."
] | [
"Of course. Think of it like this: Anything with mass has a temperature and therefore emits some light. (See black body radiation.) Even though the radiation emission from an object has some peak wavelength, there is still some emission across the EM spectrum. This means that by observing distant objects with a var... | [
"Why? What about near-IR/UVvis sources?"
] |
[
"If a foreign object was in orbit around the earth, how long would it take for us to realize it was there?"
] | [
false
] | This isn't about aliens or anything, I'm just interested in how aware we are of the objects in the sky above us. | [
"If it was bigger than a baseball and radar-reflective, at most about 2-3 orbital periods. Earth orbit is monitored pretty closely by NORAD - in the particular band they use for their \"radar curtain\", we're the brightest known object in the galaxy."
] | [
"Oh, I meant by intrinsic spectral radiance -- measured in total watts per unit frequency per unit area.",
"Now that I think about it I no longer have the numbers handy, so I can't properly defend the assertion -- but with a handy envelope: one must figure they radiate something like 10",
" Watts at something ... | [
":-) No, I mean as in luminous flux."
] |
[
"Does Mitochondrial DNA expression vary?"
] | [
false
] | Given that they are not multi-cellular organisms I wouldn't expect individual mitochondria within a cell to have different roles. However within different cells on a multi-cellular organism (neurons, skin, eye, etc) do the mitochondria contained express differing genes of their own DNA to make proteins specific to that... | [
"As tempting as ",
"/u/Mitaines",
"'s logic is, a quick search shows that expression from mitochondrial DNA (mtDNA) does in fact vary between tissue types in humans. This actually becomes less surprising when you discover that many of the proteins encoded in mtDNA are involved in oxidative ",
"phosphorylation... | [
"Different genes as in gene A is expressed in tissue X but not at all in tissue Y, no. ",
"Different levels of the same gene? Yes, absolutely. High energy tissues will have comparatively higher expression of the mitochondrially encoded components of the electron transport chain. Mitochondrial mRNA and tRNAs are a... | [
"Thanks for the correction ",
"/u/dazosan",
"!",
"You can find exactly what dazosan said in this paper here: ",
"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2408405/",
"\n\"...signaling pathways must exist to coordinate the activities of these distinct genetic compartments (the nucleus and mitochondria) t... |
[
"Hypervelocity Impact on front page got me thinking... (speed + gravity question)"
] | [
false
] | People in the post started talking about a "Rods from God" weapon system devised in science fiction, where objects where hyper-accelerated in orbit towards the planet. My question is, once something is going several times the speed of sound, from orbit, does the Earth's gravity really do all that much to speed it up fu... | [
"Sure it doesn't slow the projectile down, but does it really speed it up meaningfully? Does being in orbit have an advantage other than ease of \"line of sight\" to target?",
"I can think of 2 advantages to launching a projectile from orbit: ",
"You won't experience any drag until you are close to the target (... | [
"I recognize this, but I'm curious if the gain in speed is significant. I realize every bit of increased speed will increase the power of the kinetic impact, I'm just curious how much.",
"I guess the root of my question is: If you have a tank 10 miles from your target that can fire a slug at mach 10 at the targ... | [
"The thing is if a tank launched a projectile at Mach 10 on the ground, by the time it hit the target it would have slowed down significantly by the time it hits the target.",
"However, from space (let's say geostationary orbit - 250km) the projectile might reach up to Mach 15-16 before starting to slow down. ",
... |
[
"How big of an object would we need to create an artificial atmosphere in space?"
] | [
false
] | [deleted] | [
"It wouldnt need to be that big, they create a breathable atmosphere in the space station at all times, major problems would be scale, the bigger the ship the bigger the air cleaning systems would have to be"
] | [
"He means an atmosphere ",
" an object, not ",
" a hollow one.",
"I'm not sure on the requirement of gravity, but I do know that it depends on location as well - Titan has a heavy atmosphere, but Mercury, which has a much higher mass, hardly has any atmosphere because it's closer to the Sun. The closer your o... | [
"Solar wind has no effect on atmo it never touches it, the magnetic fields shield it, which is something you would have to create as well if you wamt to live on something as opposed to in it. Gravity also has a role here, the amount of atmosphere an object can maintain depends on its gravity. More gravity meams you... |
[
"What happens to black holes during universal heat death?"
] | [
false
] | null | [
"If Hawking is right, they'll eventually \"evaporate\" due to Hawking radiation, where they slowly lose mass due to quantum processes near the event horizon. This takes a really long time for really really massive black holes; if a supermassive black hole that was a billion times the mass of the sun never gained an... | [
"The rate of energy loss due to evaporation today would be less than the rate of absorbtion of light from stars, so any black holes existing today, even if they're not near any mass to absorb, will not be decreasing in mass.",
"Even after the stellarluminiferous era, the rate of energy loss from Hawking Radiation... | [
"The rate of energy loss due to evaporation today would be less than the rate of absorbtion of light from stars, so any black holes existing today, even if they're not near any mass to absorb, will not be decreasing in mass.",
"Even after the stellarluminiferous era, the rate of energy loss from Hawking Radiation... |
[
"Why is it that a lit candle doesn't produce any smoke until after you blow it out?"
] | [
false
] | null | [
"This was answered by errantdog a few months ago: ",
"here",
"."
] | [
"thanks"
] | [
"You're welcome. I hope that answered it sufficiently for you?"
] |
[
"Why are iron (Fe) and cobalt (Co) good catalysts for creating hydrocarbon chains?"
] | [
false
] | I've been reading on slurry bed reactors, and i know that cobalt is more power efficient (less heat required) than iron in reactors, but what i don't understand is the mechanism which Co or Fe allow Carbon Monoxide (CO) and Hydrogen (H) to do this: (2n+1) H2 + n CO → Cn H(2n+2) + n H2O I have no chemistry backgrou... | [
"There are at least three possible mechanisms, and which one predominates may depend on temperature, pressure and catalyst. As to why these metals (and nickel and ruthenuim) are good, other metals would give either different, less useful products or nothing at all, or not be stable under the conditions. All these m... | [
"In general terms, transition metal catalysts act by two methods. First the metal centre is very highly positively charges and very electronegative - it will attract the electrons forming bonds and in other parts of the molecule. This polarises C-C bonds in the growing chain and allows insertion of another group. T... | [
"i think i saw a video of a guy with a weed wacker and gasoline...",
"but seriously, what you're asking is more of a non combustion temperature bake off of impurities so the forged metals dont absorb any of those gases. hydro carbon chains though? idont remember that from the video"
] |
[
"Can the material taken with nasal swab test for CoV-19 also be used to look for other viruses after testing for CoV-19?"
] | [
false
] | We're taking more samples from people than ever. I'm wondering if the samples taken could also be used to monitor other infections to improve our understanding of other pathogens. Also, is human DNA also being unintentionally collected with these swabs? It's a dark thought, but are we surrendering our DNA unwittingly w... | [
"Yes. For example, the CDC lists a bunch of assays that can simultaneously test for COVID-19 and influenza (",
"Multiplex Assays Authorized for Simultaneous Detection of Influenza Viruses and SARS-CoV-2 by FDA",
"). A couple of these are commercially available. At the research level, there are ways to test for ... | [
"However, most if not all these assays are more complicated and harder to run than the simple single-pathogen tests, so it’s not done for everyone who walks up to a testing facility. ",
"Nah. Multiplex PCR tests are generally very automated. BioFire's FilmArray system, for example. 21 targets, bacterial and viral... | [
"Testing complexity has a specific definition for the US FDA. \"High/moderate\" means a test must be operated by a qualified individual, i.e. someone with a specific clinical laboratory science education or significant training. The alternative, \"waived\" testing, can be done by anyone, and has pretty tight restri... |
[
"When a video game runs at 60 frames per second, does that mean only the display shows what happens every 60th of a second, or does the game have markers that take inputs and produce outputs only at those times too?"
] | [
false
] | For example, I know that the CPU that's processing everything can make a cycle every couple billionths of a second, and all though it would take a lot of them to produce a result, taking an input and sending it to the game should be very fast, and be able to happen in between frames, right? So for instance say there's ... | [
"It depends on the game.",
"Minecraft will draw frames as often as your GPU and your monitor can handle, but the physics system only \"ticks\" once every 1/20th of a second. Time happens in 50 ms slices. If you and a friend both hit two buttons to start two redstone clocks at the same time to within a few millise... | [
"You can move your view faster than 20 fps but the world is rerendering yes."
] | [
"Missing some details. You would have to explicitly code the engine to note the time of the keypress as well, that is not a standard feature. Most games ",
" just go to the basic \"The key has been pressed since last frame and then result in a tie. Unity engine by default, for example, merely tracks that inputs ... |
[
"Why are some liquids easier to blow bubbles in than others?"
] | [
false
] | Like milk for example. Every child knows that if you put a straw in a glass of milk and blow it produces a bunch of bubbles, yet if you do it to water, it only produces smaller bubbles which pop really easily. So what is it with milk, and any other liquids like milk, that makes it produce these kind of bubbles? | [
"In essence yes this is right, but more in depth it is due to the increased viscosity and increased surface tension in milk and other liquids that provides the increased bubble ability. Similarly if you look at the long chain molecules of soap its essentially the same thing as long chain fats and proteins that are... | [
"Simple answer: due to proteins and fat present in the liquid. "
] | [
"Ah, makes sense, thank you! :D"
] |
[
"Some species don't breed in captivity. Why? What's keeping them?"
] | [
false
] | [deleted] | [
"It depends, which species are we talking about? Some are lacking the proper natural and biological signals they would get in their natural habitat signaling breeding season, or for other species just a general depression from being held captive. Other species may just reject the mate chosen for them or be unable t... | [
"Behaviors specific to the species that can't take place in a confined environment. ",
"Honey bees ",
" can be raised in complete captivity, fed sugar water and pollen or pollen substitutes. This is not how we normally raise them however, under normal conditions they have open access to the outdoors. They will... | [
"Ocean fish are really bad with breeding in captivity. Salmon has been figured out, Sturgeons on a smaller scale and progress has been made for the important Bluefin Tuna.",
"\nMost of the rest... no one knows. There is big, big money to be made for people who figure out how to breed an economically important fis... |
[
"On the cellular level, would animals be more \"complex\" than plants?"
] | [
false
] | Im sure that is a vary naive way to word my question, so ill try to elaborate. If we look at a substance, on the cellular level, would the cells/bacteria/microorganisms be more evolved, on a plant substance (leaf, grass etc) or on a Animal substance (muscle, flesh tissue, blood etc)? | [
"There's ",
"a type of fern",
" with over 1000 chromosomes, if you want to consider that in your definition of complexity. "
] | [
"\"Evolved\" is a loaded term that begs the misconception that evolution always progresses by some measure. But if you just ask about complexity, there could be a good case for plants being more complex at the cellular level. They are little friggin chemical factories, making tons more complex molecules than animal... | [
"I'd argue that plants are more complex on a cellular level. They have structures like cell walls and chloroplasts that animals don't have, and they have pretty complicated biochemical abilities. Animals (usually) deal with the environment by moving around, sensing, and responding. Plants are (mostly) stuck in o... |
[
"A question about Firesticks, Space Canoes and Explosive Decompression (asked in AskReddit, not a lot of interest)"
] | [
false
] | Spaceship (et al) decompression is widely portrayed in sci-fi, and I was just wondering how realistic the various portrayals are. Like in Alien Resurrection when the hybrid gets sucked through the tiny hole - would that happen? Or would it be more akin to a hoover sticking out of the wall? Or somewhere in between? What... | [
"Atmospheric pressure is only about 100k newtons per meter. So, a hole of 1 meter square can only have a maximum force of 100k newtons, which is not actually that much.",
"Explosive decompression/compression in deep water dives is much more dangerous, because the pressure differential can be much greater. There... | [
"extremely fatal"
] | [
"Just thinking about this as a semi-science-literate layperson -",
"In our everyday experience, water pressure produces much greater force than air pressure. (Tens of kilometers of air on top of us produces a pressure of a couple of kilos, whereas we can't dive deeper than a few dozen meters in water without suff... |
[
"It rains sulfuric acid on Venus. Is there a constant fog of sulfuric acid in the atmosphere, or occasional storm clouds of acid?"
] | [
false
] | Could you occasionally use an acid proof umbrella or would you constantly require an acid proof suit if you were in the upper atmosphere? If you had a floating habitat high enough in the atmosphere to have a survivable temperature, could you walk around unprotected with an oxygen mask? | [
"The clouds of sulfuric acid that obscure our view of the surface only exist above an altitude of around 48 km and rapidly thin out with increasing altitude. In the upper atmosphere, photolysis of carbon dioxide by UV radiation from the sun gives carbon monoxide and atomic oxygen, the latter of which oxidises sulfu... | [
"The one atmosphere line (the altitude where humans would be most comfortable without a pressure suit) is 50 km above ground.",
"You'll have to make some compromises to live anywhere except Earth, but Venus is asking a lot."
] | [
"Venus is constantly obstructed by sulfuric acid clouds. The sulfuric acid rain on Venus never reaches the ground. As it falls it warms up and evaporates again.",
"The optimal altitude for a floating habitat (based on atmospheric pressure) is right between the sulfuric acid clouds and sulfuric acid haze. Thus you... |
[
"What is that high pitched ringing sound you hear when you turn on a television?"
] | [
false
] | null | [
"My friend didn't believe I could hear this, so we ran a series of trials where I backed into the living room with my eyes closed and told him whether the TV was on or not. I achieved a perfect record but he still didn't believe me."
] | [
"Thanks, I always thought it might be some form of tinnitus caused by being close to electronics. TIL otherwise! "
] | [
"Thanks, I always thought it might be some form of tinnitus caused by being close to electronics. TIL otherwise! "
] |
[
"Do all living things use electric impulses throughout their bodies to move and do everything else?"
] | [
false
] | From my (admittedly limited) understanding of human beings' bodies, I assume that we use electric impulses throughout our entire body to move and do pretty much everything else that is required to be alive. Is this true of other organisms? Are there any creatures out there that manipulate their bodies in some other way... | [
"The neural system, in evolutionary terms, is a pretty recent invention. It allows for very fast communication between different cells within a multicellular organism. It allows an organism to integrate stimuli from the environment and produce a single response to them. ",
"For any unicellular organism, there is ... | [
"Exactly, a multicellular organism that does not use nerve mediating communication between cells is theoretically possible but I could not envision it surviving for long in an environment where it was competing for a niche against an organism with nerve mediated intracellular communication. The response time of thi... | [
"Cyclic AMP acts as both a paracrine signal and an intracellular signal, with cAMP detecting G-protein receptors being present on the outside of the cell. The receptor upon binding cAMP triggers the activation of Adenylate Cyclase, producing cAMP inside the cell that also diffuses out of the cell. That amplifies th... |
[
"Why do we assume so much about Quantum Physics?"
] | [
false
] | null | [
"Anybody who describes entanglement as \"instantaneous communication\" has no idea what they're talking about. Not only is that not at all what entanglement is, but the no-communication theorem actually says that that's impossible."
] | [
"Correct. I'm not referring to an ability for US to transmit information instantaneously. Rather, I was referring to the idea that information about their state IS transmitted instantaneously upon observation of one particle. Hence the \"strange behavior at a distance\" phrasing. "
] | [
"There is no instantaneous transfer of information whatsoever."
] |
[
"How is my computer password (eg. log in) stored on my computer and how safe is it compared to how a website would store that password?"
] | [
false
] | I've seen videos on hashes and and the correct and safe ways for websites to store your username and password, but what about on my PC? Back when I had a macbook I used to be able to access pretty much every password I'd saved with a built in app called 'keychain access' or the likes I don't know if that's a thing with... | [
"Log-in passwords to access a computer and \"stored passwords\" inside an application can use two different mechanisms.",
"Typically the password you use to log-in in a computer is not stored in a way that allows to be recovered. A function (a kind of hash) of the password is computed and stored and when you try ... | [
"The website will request your PC to send the password in clear text (over an encrypted connection - don't type your password if that is not the case). This is a security requirement so that any leaked hashes can't be used by the bad guys to impersonate you.",
"So if you have any passwords stored in your PC, ",
... | [
"And again, security of the keychain depends on the strength of the password used to encrypt it.",
"The mathematics behind any modern cryptosystem can be assumed to be unbreakable, so you have to look at\nsurrounding factors: besides the weakness of simple passwords to brute force, there would also be the obvious... |
[
"What would we see if there was an object that absorbed 100% of the light photons that hit it? Just a black space?"
] | [
false
] | null | [
"It would be black, no matter what spectrum of light/electromagnetic waves you are sensitive to (radio, visible light, microwaves). A black hole would do that (though with a black hole there are additional effects due to its strong gravitational field, such as the bending of light that passes close to it.)",
"Int... | [
"A black holes event horizon absorbs 100% of the photons that hit it. ",
"We see nothing, essentially, but it's outline against anything it occults and anything that may be in front of it. "
] | [
"Note that the whole \"virtual particle pair near the event horizon\" explanation is purely heuristic and may not (in my opinion, probably does not) actually correspond in any way to what's \"really going on\" at the particle level. No one has ever worked out a complete particle description of Hawking radiation (do... |
[
"Is talc really the softest substance? What is 'softness' anyway?"
] | [
false
] | null | [
"Substance? Probably not but it's the softest mineral according to the ",
"Mohs scale",
"."
] | [
"The hardness scale is based on what can scratch what. Diamond can scratch everything, corrundum everything but diamond, etc. Everything else on the scale can scratch talc."
] | [
"Poor talc. :("
] |
[
"Could a blood transfusion potentially help coronavirus patients who are in critical care?"
] | [
false
] | Apologies if this is a ridiculously stupid question but curiosity got the better of me. From my very basic understanding, severe cases of Covid-19 result in breathing difficulties and not being able to circulate oxygen to organs in the body. So it got me wondering, if the patient received oxygenated blood whilst removi... | [
"Short answer: a blood transfusion would probably help only a little bit—and probably not enough to make it worthwhile except if the patient already needed blood for other reasons. This is because providing more blood doesn't fix the apparent underlying problem in severe COVID-19, which is lung failure.",
"Long a... | [
"I think you underestimate the quantities that would be necessary. Breathing takes in about 8 litres of air every minute and extracts about a quarter of the oxygen. So that's two litres a minute. Maybe you could reduce that a bit by cooling the patient down but it still needs significant amounts. It is done for t... | [
"Thank you for a comprehensive and thorough reply. I really enjoyed reading it and I’ve definitely learnt something new."
] |
[
"If wood is suspended on the surface of a liquid with a higher boiling point than ignition, could the wood burn despite being wet?"
] | [
false
] | Assuming only the top surface of the wood is exposed to air. | [
"The autoignition temperature of wood is close to 300C, so you'd need a very hot liquid. If the wood is floating on liquid metal at a temperature of 400C (for example), then heat will transfer to the wood until it's at a high enough temperature that the portion exposed to air will catch fire.",
"If you had the wo... | [
"Wood needs oxygen to burn. If a liquid is hotter than the ignition temperature of wood, chances are, it is heating the surrounding air enough to ignite it. The \"wet\" side of the wood would probably not burn due to lack of oxygen, but would be converted to carbon (charcoal) with enough heat."
] | [
"Do you sail? Curious what you do that you're near wooden sailworthy ships often :P"
] |
[
"Are stem cells really that \"next big thing\" as advertised? Why or why not?"
] | [
false
] | I don't really understand much about stem cell biology, only that it is very concentrated in the bone marrow, and that it can take the function of any other cell in the body. Is that it? | [
"The potential implications of stem cell based regenerative medicine are huge for medicine. While most stem cell therapies that go on today use adult stem cells like the hematopoietic stem cells in the bone marrow for blood cancers or ",
"immune related disorders",
" or ",
"mesenchymal stem cells",
" which... | [
"Stem cell biology and the associated engineering is incredibly exciting, BUT",
"I'm skeptical of most therapies involving stem cells in the near to medium term future, with a few exceptions.",
"The thing is, diseases are complicated, multifacted, and incompletely understood. I'll list a few examples and give s... | [
"When a zygote is formed (i.e. when sperm and egg join) it divides over and over to form the cells that will eventually be the body of the new organism. These cells, up until a certain point in development, are called embryonic stem cells (ESCs). After the body is formed and development is well underway, most cells... |
[
"'Human Body' Would it be more beneficial for us to fuse with machine or to skip fusion and start development into gene modification?"
] | [
false
] | null | [
"This kind of conversation is very open ended and calls for speculative answers even from specialists. ",
"/r/AskScienceDiscussion",
" is better suited for this type of question."
] | [
"Hi SpicyBeardedWarlock 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... | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"For more information regarding this and similar issues, please see our ",
"guidelines.",
"/r/AskScienceDiscussion",
"Please see our ",
"guidelines.",
"If you disagree with this decision, pleas... |
[
"Nuclear meltdown leading to critical mass?"
] | [
false
] | A friend of mine has said that if uranium rods in a damaged nuclear power plant meltdown, the uranium can pool together and reach a critical mass, causing an explosion. Is there any possibility of this actually happening? If so, what would the exact effects be? | [
"No, there is not enough uranium in a rod to create a nuclear explosion."
] | [
"The fission chain reaction was stopped when the reactor was SCRAMed following the earthquake. But if all the rods melt, and the fuel pools at the bottom of the reactor, it could go critical again. This would lead to the generation of more heat, and exacerbate the problems they are already facing with heat remova... | [
"In order to make a massive nuclear explosion, all that uranium has to be held together by precise force for an extended period of time. One explosion a few meters away might make all the uranium go together, but then a fission reaction would start, and the critical mass would rip itself apart before a REAL nuclea... |
[
"How long could you survive at absolute zero temperature? (−273.15°C or −459.67°F)"
] | [
false
] | I'm guessing we're talking second(s) (or less). Or would you just be damaged enough instantly that you wouldn't be able to recover? | [
"It's all in the rate of heat transfer. The vacuum of space (not near a star) is incredibly cold, but heat transfer only occurs through phase changes and radiation which would take some hours to kill you (assuming you had a pressure suit and air, but not proper insulation or HVAC). However, if we had a medium, like... | [
"Matter won't behave in any way at zero temperature, because it is physically impossible to get there in the first place. That's just like asking how matter would be have when going at the speed of light or faster - there's no physical answer because the starting assumption is already wrong."
] | [
"For this reason, and since the OP didn't specify how the body would be cooled, I submit a paradoxical seeming answer that a person would survive indevinitely at absolute 0. There would be no functioning \"life,\" but provided there was no external influence, the body would remain exactly the same until the heat d... |
[
"Can we grow babies in labs?"
] | [
false
] | Since we can artificially inseminate a human embryo is it also possible to create an artificial womb and "grow" a human? If not is it a questions of ethics or technology or both that prevent us from doing it. If technology is the issue how long until we can do it? | [
"AFAIK, we are not there yet. Mother's placenta is an amazing evolutionary feat that is not going to be easily reproduced anytime soon. ",
"Artificial placenta is the key: ",
"http://en.wikipedia.org/wiki/Artificial_uterus"
] | [
"TIL how important and complicated the placenta is. "
] | [
"Thank you?"
] |
[
"What would Earth's climate be like with a zero degree axial tilt?"
] | [
false
] | I've always wondered what Earth's climate would look like without any kind of axial tilt. My understanding (though quite laymen) is that almost all weather is created by thermal differences in the oceans which is produced largely by the tilt itself. Now obviously there would still be thermal differences, even without... | [
"Seasons would be nonexistent.",
"The Earth's axis remains tilted in the same direction with reference to the background stars throughout a year (throughout its entire orbit). This means that one pole (and the associated hemisphere of the Earth) will be directed away from the Sun at one side of the orbit, and hal... | [
"The earth's orbit is only slightly elliptical. We probably wouldn't notice a difference."
] | [
"The issue with axial tilt is not added/decreased distance but the angle with which sunlight strikes the surface, and the amount of sunlight the hemisphere gets.",
"In winter days are shorter, yes? So there are fewer hours for the sun to warm the ground and air.",
"Additionally, take a flashlight and shine it s... |
[
"Why is our blinking synchronized between both eyes?"
] | [
false
] | null | [
"Medical student here. Just finished neuroscience, so I feel like I should share so that least SOME of the minutiae they taught us is useful... ",
"The closing of the eyelid is controlled by the orbicularis oculi muscle, which is innervated by the facial nerve (cranial nerve 7). Many cranial nerve functions are... | [
"Both eyes are connected via the ",
"Median Longitudinal Fasciculus",
" that runs in your brainstem. It gives the information to each eye so that they know what the other is doing and can make coordinated movements. It's why you can look right and both eyes will follow even though they use different muscles f... | [
"Additional question: Similarly, does synchronized blinking have anything to do with the way we have synchronized eyeball movement?"
] |
[
"What does the ISS use to protect its solar panels?"
] | [
false
] | I understand that we track large objects and activate thrusters long before a collision that helps protect against major impacts, but what about the small stuff like bolts and nuts from failed space craft and other small rocks? It seems like we would not be able to track every single piece of debre out there, so what d... | [
"On top of that, debris that would hit the space station should be travelling on the same orbit and therefore have a similar speed",
"Not necessarily. You can have similar orbits intersect, even if they have a similar periapsis and apoapsis, if you have one object in a different orbital inclination (such was the ... | [
"I don't think they use anything. Space is BIG and even if there are plenty of debris in orbit, they are really far between and the probability of hitting anything is still very low. ",
"On top of that, debris that ",
" hit the space station should be travelling on the same orbit and therefore have a similar sp... | [
" If you've been to ESTEC open day, they have a former panel from the Hubble space telescope that was replaced and is now exhibited there, when you look at it closely you can see it's full of impact craters. NASA must have similar things exhibited. You can also check here: ",
"http://orbitaldebris.jsc.nasa.gov/me... |
[
"How would blood pressure and blood volume be affected by the loss of a limb?"
] | [
false
] | [deleted] | [
"tl;dr: Red blood cells are produced by marrow, and it responds to decreased oxygen delivery to the kidney. Volume is also controlled by the kidney, and it responds to changes in pressure in the arteries. Both of these systems can respond to loss of a limb.",
"You're right that blood cells are produced by bone ma... | [
"Very informative, thanks for taking the time to write that out!"
] | [
"Very informative, thanks for taking the time to write that out!"
] |
[
"Several questions... How would a \"cloud\" of hydrogen gas behave in space, under various conditions? Would it expand or diffuse? Would it collapse under its own gravitational field? Also, If there was a big enough \"rock\" in space, would it collapse under its own gravitational field?"
] | [
false
] | Me and my friend are having a disagreement about how gravity affects matter (granted we both have a poor understanding of the subject). I am of the opinion that a big enough object would not necessarily collapse under its own gravitational field, and he is of the opinion that as long as sufficient mass is reached a bla... | [
"Hydrogen at any reasonable temperatue would diffuse, since it's random motion due to the temperature would overcome the tiny force of any gravity. If you compress the gas enough, and there is enough of it, and it's cold enough, then it might collapse in on itself due to gravity.",
"As for the rock: every object ... | [
"So a single hydrogen molecule in space at 3K will have a kinetic energy of 6.21x10",
" . The gravitational potential energy given by a single hydrogen molecule to another is (7.48x10",
" / r), where r is the distance between the two molecules. This means that for gravity to overcome the energy from heat, the t... | [
"My conceptualization of gravity entails that it emanates from every part of the mass of an object, not just the center. When you are outside of the object I understand why you use the center as a reference point to calculate the overall pull that a circular object will have on you, but once you are inside it you r... |
[
"After listening to RadioLab's recent episode about symmetry, a question about matter/antimatter has been brewing"
] | [
false
] | They mentioned that for every billion "pieces" of antimatter, there are like a billion and one pieces of matter. And that extra matter eventually accumulates and interacts and forms stars and planets and heavy elements and eventually life. But, if there had been a bias toward antimatter, would/could life still exist ... | [
"Well, not the exact same properties. Antimatter can behave differently under the weak force. This is what gives rise to CP-Violation and is believed to be why matter fills the observable universe instead of anti-matter."
] | [
"Yes, antimatter has exactly the same properties, chemistry, etc. as regular matter; the only reason that one has primary status is because it's what we're made of. We could just as well call what we're made of \"antimatter\" and call positrons, etc. \"matter\"."
] | [
"It kinda matters what the OP means by bias. If he means that CP-violation would favor anti-matter in the same way that it currently favors matter, then he would basically just be swapping their names. All the attribute which are unique to anti-matter would be transfered to matter and vice-versa.",
"However, if... |
[
"Solid Rain is said to be a super-absorbent polymer that can soak up more than 500 times its own weight of water. Given that mountaintops have snow, if we make a very tall elevator, could we harvest humidity from the sky even in deserts?"
] | [
false
] | if these technology in the future could soak-up even more water in reasonable amounts of time, ¿could we bring down liquid (given that mountaintops have snow) by elevating these kind of polymers and leave them X time up there, all these in the middle of the desert? | [
"Based on the press release, you can't use these like millions small buckets to transport water from one place and dump it in another. That is, its not like a wash cloth that you wring out. Instead its like hair gel, that slowly dries out. But, I'm not really sure without seeing a paper describing its properties... | [
"Yes, but there's limited atmospheric moisture over a desert, mountains near deserts have snow/ice on top because they form a ",
"rain shadow",
"."
] | [
"I trust nothing like this until I see a peer reviewed publication. For all we know, there is 10 grams of this stuff. "
] |
[
"Does the same food have the same amount of calories as it is cold when it's hot?"
] | [
false
] | null | [
"More or less, yes. Especially for a processed food like a frozen pizza.",
"For fresh foods, cooking makes them both more and less nutritious, depending on the food and the cooking method. Cooking can break down hard-to-digest molecules and make them more available to you, but it can also break the structure of... | [
"If it's the same object with no chemical changes, just at different temperatures, then yes, it's the same calories.",
"If the heating or cooling causes chemical change (which is a process we sometime call 'cooking'), then yes, the calories could change as the molecules change into thing that are easier or harder... | [
"Because of how the calories are defined if the chemistry is unchanged so are the calories. However if you eat cold food it will cool down your body slightly and your metabolism should increase to counter the change slightly."
] |
[
"How Feasible is a Nuclear Powered Locomotive"
] | [
false
] | I was looking over forum as I was google searching the answer, and only understood a small portion of the specifics mentioned. Can anyone shed some light in layman's terms? | [
"Feasible, but there's no particular need to build such a thing, and having a nuclear reactor racing around the countryside isn't necessarily a good idea. ",
"Relevant - ",
"http://en.wikipedia.org/wiki/Nuclear_marine_propulsion"
] | [
"What warrickneff says is true of trying to miniaturize modern nuclear reactors. However there is another possibility in LFTRs (Liquid Fluoride Thorium Reactors). They ARE nuclear, but function VERY differently from what would be considered a traditional nuclear reactor. There were even plans in the 50s and 60s bef... | [
"We already have electric subways and trams that are powered by rails or overhead lines. The problem is that installing the required infrastructure isn't cost effective for long distance rail transportation."
] |
[
"If astronauts lose bone mass in low gravity, do they gain it in high gravity?"
] | [
false
] | And what could the human skeleton look like after being exposed to high gravity for a prolonged period of time? | [
"I dont think anyone has done any LONG term studies. best i can find is maybe 24 hours in a centrifuge, considering its a box barely large enough to lay in, its not something you can really live in for weeks.",
"In theory though... yes, we should adapt, though perhaps not all of the adaptations would be healthy.... | [
"In the absence of evidence, it is probable to some limit. Having a high Body Mass Index is loosely correlated with Bone Mineral Density.",
"A simple formula used in clinical practice is the OST (Osteoporosis Self-Assessment Tool) which is used as a pre-screening for Osteoporosis, which is characterized by low Bo... | [
"Thanks for the detailed reply!"
] |
[
"Do animals with shorter life cycles have a faster evolutionary process?"
] | [
false
] | If the reproductive cycle happens in days instead of years, does the speed of evolutionary change increase. | [
"In a way yes and in a way no.Yes, in that a shorter reproductive cycle will allow for faster accumulation of mutations. All evolutionary change is the result of a mutation in the genome. But the major drive of the /speed/ of evolutionary change, as you asked, is the mutation rate - how often the process of DNA re... | [
"Here",
" is an article on those fruit flies which were kept in the dark for 57 years (1400 generations). Over 240 genes in the fly's genome showed point mutations."
] | [
"Here",
" is an article on those fruit flies which were kept in the dark for 57 years (1400 generations). Over 240 genes in the fly's genome showed point mutations."
] |
[
"Is it possible to kill a star by introducing enough foreign iron to it?"
] | [
false
] | [deleted] | [
"Interesting question! For a low mass star, this will only lead to the star imploding once you reach 3 solar masses. Now, where will you get >2 solar masses of iron? For a high mass main sequence star, it will be difficult to add iron given the star will simply blow it away by powerful stellar winds. Say you can ma... | [
"I think the OP is thinking that since stars die out when they start creating iron, sending some iron in a star could be used to kill it. But of course it's not the iron that's killing the star in the first place. It's just that when a star is about to die, processes take place which happen to create iron. (Or at l... | [
"I think the OP is thinking that since stars die out when they start creating iron, sending some iron in a star could be used to kill it. But of course it's not the iron that's killing the star in the first place. It's just that when a star is about to die, processes take place which happen to create iron. (Or at l... |
[
"Can we communicate via quantum entanglement if particle oscillations provide a carrier frequency analogous to radio carrier frequencies?"
] | [
false
] | I know that a typical form of this question has been asked and "settled" a zillion times before... however... forgive me for my persistent scepticism and frustration, but I have yet to encounter an answer that factors in the possibility of establishing a base vibration in the same way radio waves are expressed in a car... | [
"I think you are basically proposing the sort of thing discussed ",
"here",
". Your question is actually a good one and the explanations why it doesn't work are not general (",
" actually they are pretty general, see below), but every specific example studied has nonetheless found that no FTL communication is... | [
"I was under the impression that the no-communication theorem was pretty general.",
"http://en.wikipedia.org/wiki/No-communication_theorem"
] | [
"Look at it this way: Information wasn't sent FTL, the two parties just found out the same information at the same time.",
"Handing someone a note and saying \"Don't read this until you're across the galaxy\" is not the same as \"I'll text you the meeting place when you're across the galaxy\".",
"I don't know i... |
[
"Permeation of heavy water (D2O) through garments?"
] | [
false
] | My knowledge of chemistry is somewhat limited but I have a question pertaining to an project I'm working on. My question is: If you were to spill heavy D20 on some sort of cotton garment, would it permeate through to the other side at a faster or slower rate than normal water? If faster, approximately how much? Any ans... | [
"As far as I know, wetting is related to surface tension and surface energy. I can't imagine that D2O acts that differently than regular water, and they have very similar surface tensions (~72mN/m). I would guess that the difference would be very small. The viscosities are different by a perceptible amount (~0.25 m... | [
"Alright now for the second part of my loaded question:",
"What would you have to do to water to get it to permeate through materials faster? even an educated guess is good.",
"edit* I should also mention that this substance would not be a corrosive or otherwise harmful to humans",
"-bangbang "
] | [
"What are you trying to achieve? A little explanation would help a lot. If you're simply trying to filter it with a 'garment' you won't be able to isolate any significant amount."
] |
[
"Could it be possible for a species to have one sapient sex and one non-sapient sex (e.g. the Kzin)?"
] | [
false
] | Larry Niven writes some pretty fantastic aliens, including the not-just-your-everyday-cat-alien Kzinti. In his stories, the Kzin evolved with both sexes of equal intelligence, but after a very long time with serious eugenics (controlled breeding), the females were reduced to being of merely animal intelligence, while t... | [
"I don't see why not. There are lots of species that exhibit extreme ",
"sexual dimorphism",
", or where one sex is radically different than the other.",
"edit: in a totally unrelated note, after reading the article, TIL that there is a evolutionary biology theory called the ",
"sexy son hypothesis"
] | [
"I've always thought that anglerfish were particularly interesting for this reason."
] | [
"I read about a species of worm where the females are worms and the males are microscopic bugs inside them."
] |
[
"I drank a lot last night and went to sleep at about 11. At 8 this morning, I wake up and still feel drunk for about another hour. Surely I've processed the alcohol in this time and shouldn't feel drunk anymore. Whats going on?"
] | [
false
] | null | [
"How much is \"a lot\"?",
"And over what period of time?"
] | [
"There was probably still alcohol in your system. I went to driving school years ago and the cop said that they have given a lot of DUIs in the morning when people were on their way to work. "
] | [
"James May explains much better than I can:\n",
"http://www.viddler.com/v/eee6aa08",
"Probably best not to drive if you feel incapacitated in any way."
] |
[
"What causes sudden unilateral deafness?"
] | [
false
] | So I'm kinda of depressed that it's been almost 1.5 years since I woke up deaf in my right ear on January 2, 2010 and I just can't get this off my mind. What happened to my right ear? Why did it suddenly stop working? I just woke up one day and I wasn't able to hear anything from my right ear. I had tinnitus, which I s... | [
"The ENTs where I work will tell you: it's idiopathic, meaning they have no clue. (As one guy says, \"it means we [doctors] are idiots, and we don't know!\"). There will probably never be a way to understand your specific case, but there are many possible explanations. Could be viral, could be inflammation, could b... | [
"Yes, I got an MRI scan. Nothing showed up."
] | [
"By co-incidence I just read this over on the BBC yesterday. ",
"Single Sided Deafness",
"."
] |
[
"Can the start codon be found in a non-codon triplet? Then can you start the codon sequence?"
] | [
false
] | Let's say that there is an mRNA strand that is like this: GAUUGACGAGAUGGUUGCCCAGU.... The start codon (AUG) is obviously there, but it is not in the codon triplet. GAU|UGA|CGA|GAU|GGU|UCC|CAG|U. My question is can you read the mRNA until the start codon and then create the codon triplets after? EX: GAUUGACGAG|AUG|GUU|C... | [
"The codon 'triplet' starts with the start codon. It does not matter how many bases are before it because the mRNA does not start getting translated until a start codon is reached. Therefore your second example is correct; however, to clarify, the mRNA is not being \"read,\" as you put it before the AUG - it is sim... | [
"Another thing people are forgetting is that there is a lot that comes before the start codon on a mRNA. To start translation, you need more than just a start site, you also need the upstream sections for the various parts of the translation machinery to sit on to start the process. I'd suggest checking out the "... | [
"Yes. The portion before the start codon is the 5' untranslated region. The reading frame is defined by the start codon, not the first base in the sequence."
] |
[
"Why do human beings only have one set of teeth their entire lives, while other species such as sharks have the ability to regrow their teeth?"
] | [
false
] | Also, with genetic engineering and future medical advancements, is it possible that human beings could ever obtain this ability? Edit: I should have specified in the title that I meant the teeth we keep our entire adult lives after deciduous teeth. Sorry about that. | [
"I received two sets..."
] | [
"Although it is quite rare there are cases about some humans having 3 or even 4 sets of teeth, but they're usually complicated. Humans don't really need more than 2 sets, our diet is relatively soft(we aren't chewing through bone or hard cartilage like a shark.) Some rodents have front teeth that never stop growing... | [
"Continuously growing new teeth (polyphydontia) is the ancestral state for vertebrates, and most non-mammalian vertebrates continuously replace their teeth throughout their lifespan. Mammals have exchanged this method for only two batches of tooth growth, and with good reason. Mammal teeth are highly specialized ... |
[
"Can you Daisy chain vacuum pumps and compressors?"
] | [
false
] | This just something I was curious about; no particular application. Let's say you had access to many weak vacuum pumps, but no high performance pumps. Each pump really just represents a step in relative pressure, right? So if you ported the exhaust of one right into the inlet of the next could you effectively reach a m... | [
"Pumps only operate on relative pressure in the viscous or transitional flow regime, which will get you down to a medium vacuum (~10 mTorr at best). I’m not sure if putting several pumps together in series in this situation would increase the effectiveness. However, if you want a high vacuum then it doesn’t matter ... | [
"What you are talking about is essentially multistaging pumps/compressors. A thing to remember is that if they are poor pumps they will still perform poorly. You may be able to multistage them and get a lower pressure but it will work very inefficiently."
] | [
"Multistage pumps are a thing because a lot of designs have a max practical pressure ratio they can achieve. Piston pumps and axial flow compressors have this problem. Part of the problem is as the pressure ratio goes up the flow rate goes down.",
"For high vacuum work multiple types of pumps are used to get to p... |
[
"How much of Antarctica is actual land mass?"
] | [
false
] | [deleted] | [
"Here's a topological map of the bedrock."
] | [
"See the legend on the side. Only the green, yellow and orange parts are above sea level. I couldn't find a percentage, but looking at the map it looks to me like very roughly half is below sea level.",
"However, that doesn't mean that the blue parts would necessarily all be underwater if the ice caps were to sud... | [
"Thanks, I guess that would have been a good place to start. I have basically zero experience with the subject and I'm not exactly sure what to do with what I'm looking at here. Care to give a rough estimate on square miles or a percentage of its total mass?"
] |
[
"Why is bacterial meningitis so deadly?"
] | [
false
] | I read that even up to 20% of people are carriers of this deadly bacteria. Can you ever be really sure that you or someone else you know got it before it is too late? | [
"A: bacterial meningitis is an umbrella term that describes any bacterial infection of the meninges.",
"B: Infections generally occur when bacteria grow in places they generally don't grow or over-grow the other bacteria in a site and are able to achieve toxic levels in that fashion.",
"C: You can't be entirely... | [
"Meningitis",
" is an acute inflamation of the protective membrane that covers the brain and spinal cord. This can result in brain swelling. The infection can also trigger sepsis, which can result in low blood pressure and excess clotting that can obstruct blood flow to the organs, and result in gangrene in the... | [
"First on why:",
"Meningitis can be caused by different bacteria. The most well known are Neisseria menigitidis and Streptococcus pneumoniae. Both are opportunistic pathogens that are commonly found in the upper respiratory tracts, but can turn deadly if given the chance (hence a lot of people being carriers). Mo... |
[
"Do changes in the Earth's rotation influence earthquakes?"
] | [
false
] | This article claims that changes in the earth's rotation contribute to more earthquakes: On the surface this seems like junk science, but I'm not really qualified to say for sure. Can anyone clarify? If so, are there any ideas as to how this works? | [
"The link between the Earth's rotation and the number of big earthquakes was unclear,",
"Beyond the clickbait, there's your needle in the haystack. The Earth's rotation has been declining progressively since its formation due to the persistent influence of the tides, the wind, and the Moon. That is a glacially ... | [
"The Earth doesn't rotate at constant speed. Each day has a different duration depending on multiple factors. Here's the official site, and a table of average lenght of day (LOD) per year, since 1623. Before 1955 those figures were estimates; since 1955 the data come from atomic clocks:",
"https://www.iers.org/IE... | [
"Yes, I missed that sentence, but that's what I thought, that the rotation slowing was a steady, extremely slow process."
] |
[
"Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! ... | [
"Is it safe to eat a pet that has been euthanized? I thought about that when a friend said they had to put down their kids' pet rabbit, and obviously that was not the time to make a joke, but still, I'm curious."
] | [
"It is not. For many reasons actually.",
"1st: think about why we euthanize animals. Normally it's because of an illness or severe injury. If it's ill that in of itself can be cause for not wanting to consume it. However, you need to also think of the state of the body. Was there organ failure that may have relea... | [
"Why do my antidepressants (mirtazapine) make me sooooooo tired?"
] |
[
"Are blood types linked to Genetics?"
] | [
false
] | null | [
"Hi penneewize 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 foll... | [
"Human body / biology"
] | [
"Human biology"
] |
[
"Is there any truth to the fact that fast food is cheaper than healthy eating?"
] | [
false
] | null | [
"Fast food is not cheaper. It is easier, tasty and relatively low cost (this is not to imply healthy).",
"If you are a savvy shopper that pays attention to food costs and buy your own food and prepare your own food you can eat for less money than fast food costs.",
"This requires time and effort though and the... | [
"I agree with a lot of what you said, but I don't think you can factor in opportunity cost. This implies that you could be earning a wage in that time. Although we can attach value to leisure time, if we are looking at actual dollars spent as the main driver, then home cooked is the clear winner"
] | [
"That assumes that we are talking about leisure time. There are people who work multiple jobs and essentially have very little time for activities other than working and sleeping. For these people, the opportunity cost of spending the time to plan meals and shop rather than simply buying fast food after working a... |
[
"Center of population math question: globe vs map"
] | [
false
] | Let's say you calculate the center of population (the point at which the total distance traveled by everyone is minimized) on a map, and find it to be somewhere near Bangladesh. Then, you calculate the center of population for the three dimensional Earth, and find it to be somewhere near the center of Earth's core, may... | [
"Assuming you are measuring distances on the surface of a globe when you say \"on a map\", the answer is no, even when the center of population is defined.",
"Consider the case of only three people on the Earth: one lives at the North pole, and the other two are at (0,0), the intersection of the equator and the p... | [
"The answer is no. Imagine that the entire population of the Earth lived only in three places: ",
"In this case, your 3-D center is clearly going to located near the center of the Earth, but it'll be very slightly closer to the giant city in Argentina, and nearly directly beneath it. (The point on the Earth's sur... | [
"Excellent answer. Thanks."
] |
[
"How do white blood cells attack a virus? Why does it take 3+ days to feel better after getting sick?"
] | [
false
] | null | [
"You mention viruses in the title and bacteria in the body of the post. They're very different. The common cold is not bacterial. Can you please clarify your question?"
] | [
"That would be due to ignorance. Okay I'll delete and report when I understand what I'm asking better"
] | [
"The post was never out on the sub, so you don't need to delete it. Let us know if we can help. People make this mistake a lot, which is why I mentioned it. Otherwise that's what most of the comments you get will say."
] |
[
"Is there any evidence that paleolithic humans were vegetarians or carnivores?"
] | [
false
] | [deleted] | [
"I'm no biologist but doesn't the fact that we have canines, incisors and molars tip you to the fact that maybe our ancestors were omnivorous?"
] | [
"We had a long discussion about this a while ago: ",
"http://www.reddit.com/r/askscience/comments/hbkjx/question_for_the_historic_cooking_scientist_as/"
] | [
"There's some interesting archaeological stuff in The Starch Solution video here: ",
"http://www.youtube.com/watch?v=4XVf36nwraw"
] |
[
"If I put a fan over my vent, will it circulate more heat into my room?"
] | [
false
] | null | [
"\"If the incoming air temperature from the vent is colder than your skin-body temperature, causing more air to circulate the room will amount to convective cooling. You'll lose heat faster and feel more cold.\"",
"This is only true if you're standing right under the vent. If the air is directed away from the occ... | [
"If the incoming air temperature from the vent is colder than your skin-body temperature, causing more air to circulate the room will amount to convective cooling. You'll lose heat faster and feel more cold.",
"If the incoming air temperature is hotter, it'll help as heat is being transferred to you and at a fast... | [
"The problem is that fan blades are designed to work over a very small pressure change. Take your fan and partially block the inlet. Notice how it starts spinning faster? That's because it's not doing anything.",
"What you want is a blower fan. Like this. ",
"http://www.amazon.com/Lasko-Pro-Performance-Blower-4... |
[
"Would a liquid-filled cockpit lessen inertia? (I'm thinking spacecraft specifically, not airplane)"
] | [
false
] | null | [
"'Physics'"
] | [
"'Physics'"
] | [
"'Physics'"
] |
[
"Would a Big Crunch reverse entropy?"
] | [
false
] | null | [
"This is a doozy of a question, and I think it's going to depend on the nature of the contraction.",
"One model that permits a big crunch begins by reversing the arrow of time, so the universe basically runs backwards from its present state with steadily decreasing entropy until some initial singularity is reache... | [
"Actually, black holes are in a state of maximum entropy, so the 2nd law doesn't have to be broken if the whole universe collapses to a black hole."
] | [
"That's because the black hole absorbs more background radiation than hawkings lets out. If there's no background to absorb,"
] |
[
"Is there any way a Non-Scientist can contribute to /AskScience?"
] | [
false
] | null | [
"If you find a question thats very interesting, do some research about it. Simple googling and a few tens of minutes can get answers to almost every question asked here in layman terms. Post what you found, with the links where you read them! There's no such thing as a \"non-scientist\", just people who have read ... | [
"Link reposted questions to well-answered threads on the same question.",
"Report inappropriate posts."
] | [
"You could give back by asking interesting questions that haven't been answered before. The experts here are awesome about answering questions that are both legitimate and scientifically interesting, or questions that can help clear up common misconceptions. Try it out."
] |
[
"Us Japan the first to land a \"rover\" on an asteroid?"
] | [
false
] | null | [
"Hi PurpleMonkeyElephant 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 o... | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"Rosetta",
"You can find the basic answer with a google / wiki search. Please start there and come back with a more specific question.",
"If you disagree with this decision, please send a ",
"messa... | [
"By the way, feel free to post open-ended question like these in ",
"/r/AskScienceDiscussion",
"!"
] |
[
"A stupid question that I will never apologise for. Is the space in-between Earth and the Sun hot?"
] | [
false
] | Right - as far as I understand, heat radiates from the sun, contacts our atmosphere and is filtered by the ozone layer. Going by the planetary order, Mercury -> Pluto is essentially hot -> cold. This seems to indicate that the radiation either loses effectiveness or dissipates over a distance - probably due to contact ... | [
"This turns out not to be a stupid question at all, because it gets to the heart of what temperature is.",
"The space between the earth and the sun does not have a well defined temperature because it is not in equilibrium. There's lots of stuff carrying energy in the solar system:",
"There's lots of stuff ther... | [
"This is just wrong. Space is neither cold nor hot since it is not in equilibrium. It does not have a well defined temperature."
] | [
"Layman here. Great post! I remember last year my Physics professor said space was 4 Kelvin. Can you explain how the 4 Kelvin even came up in the first place?"
] |
[
"Why didn't I get nauseous as a child/teen as opposed to now ?"
] | [
false
] | null | [
"Hi, I like your question, but we are trying to limit questions that are asked referring directly to the OP, especially when it could be considered medical. Would you mind rephrasing your question to something like \"Why does motion sickness tend to increase with age?\" rather than \"Why do I experience more moti... | [
"I initially didn't want to say \"why does it tend to\" because I've asked a couple of friends around and it seems like I'm the only one with that problem.",
"I guess I could just operate under the assumption and rephrase my question, thanks for the suggestion!"
] | [
"Well that's exactly why we try not to let questions with \"I\" through. What you experience may be unique to you, in which case there would not be enough information to answer it properly and it would essentially be diagnosing a medical problem. ",
"I unfortunately have the same problem, so I did a bit of goog... |
[
"Can an individual actually \"fight to live\" or \"give up and die\"?"
] | [
false
] | [deleted] | [
"Research seems to indicate that willpower or despair does not significantly affect mortality.",
"Hospital nurses (me included) can give you lots of anecdotal evidence. We like to tell stories about patients who, on being told they had a terminal illness, apparently \"gave up\" and died before the illness seemed ... | [
"Do you have a citation for that first sentence?"
] | [
"I suppose it would be more strictly accurate to say that research has not been able to show a correlation. It would be very hard to prove there is definitely no link.",
"Here's an article that reviews prior studies: ",
"http://www.ncbi.nlm.nih.gov/pubmed/15184701",
"Since we can't measure willpower and deter... |
[
"Besides ice, what mineral has the highest percentage of oxygen by weight?"
] | [
false
] | I'm also curious to know which minerals have the highest percentages of other elements. So if anyone knows a good method/website/book, I'd love to hear about it. | [
"Interesting question; I never had a reason to think about this before. I don't know the answer, but it would have to be an aluminum- or silicon-bearing oxide or hydroxide. I did some quick calculations and the best candidate I could come up with is Gibbsite:",
"Gibbsite, Al(OH)3: 61.6%",
"Diaspore, AlO(OH): 53... | [
"A great start-\nAs for \"ice,\" I have heard that this would considered an mineral if it is naturally formed. Which definition do you follow for \"mineral?\" I have not heard \"solid at room temperature\" before, though it makes a lot of sense.\nThanks again----"
] | [
"Offhand I'd have to go with crystalline boric acid (mineral: sassolite, H3BO3). Helium doesn't bond, Li2O and BeO have lower ratios. After boron, you have to go down another row in the periodic table before you get to any oxides with four oxygen atoms, and it's not enough to offset the higher mass. Hydrogen is obv... |
[
"Is pedophilia observed in nature?"
] | [
false
] | [deleted] | [
"The interesting point is that animals mate when they are physically ready to. Humans can start having children at a pretty young age (I think the earliest for girls is 9 and men are 12). The fact that we consider those ages to be too young for reproduction is based on mental abilities rather than being physicall... | [
"According to this article",
", both same-sex and adult-immature dyads engage in about as much general sexual activity as heterosexual adult dyads among bonobos and capuchins. And from other things I've read, it seems that only inter-family relationships occur less frequently among bonobos."
] | [
"Pedophilia is not a willingness to mate with pubescent or postpubescent juveniles, it's a specific attraction to prepubescent (around 8 and below) juveniles. ",
"And if you are going to use this argument: ",
"Pedophilia might show up in animals based on selecting the most 'fit' mate which would naturally sele... |
[
"How can something smolder without air? Is this a misconception, or is smoldering not a combustion reaction?"
] | [
false
] | I've always understood that oxygen was needed for combustion. I'm also under the impression that smoldering is a slow burn without a flame. So how is it possible for an underground fire to smolders indefinitely "without air". Further, in the process of making charcoal I was told that the wood is forced to smolder "with... | [
"\"Without air\" does not mean \"in a vacuum\". There is still a little bit of oxygen left. But since there isn't too much oxygen, whatever you are burning is undergoing ",
" combustion. These smouldering fires are very smokey because there isn't enough oxygen to convert all the carbon into carbon dioxide. You'll... | [
"Thanks for the start, I'll build on your answer. Wood itself contains a lot of cellulose fibers. The molecular structure of these fibers consists of very long chains of glucose molecules linked together.",
"Each glucose molecule contains carbon, oxygen, and hydrogen. When you apply heat, you break up the molecul... | [
"Particularly secondary organic carbonaceous aerosol, or brown carbon."
] |
[
"Today a yellow jacket landed on me and squirted some clear liquid on my coat. What was it?"
] | [
false
] | It was a lot of liquid. It landed, squirted it, then it flew away. | [
"Question: did the liquid have a smell to it? Bees, hornets, wasps, etc. excrete ",
"various pheromones",
" to communicate, and some of them have noted smells to them. My uncle works as a bee buster on the side, and he has had several incidents where fleets of hornets have sprayed so much alarm pheromone on and... | [
"I had a bunch of ants get into my house several years back--they were swarming and many of them had wings. I recall that whenever I would squish one it had a ",
" strong odor to it. Is this a similar situation to what you described? Probably not alarm pheromone, but perhaps a pheromone related to the swarming... | [
"It most definitely was some kind of pheromone. For exactly what I can not say. Nearly all insects use them. Ants in particular, and they have some of the most complex systems for it. ",
"The reason you could smell it, is some pheromones are rather small organic molecules which vaporize easily. There's simply mor... |
[
"When I sleep with my contacts in, why are they dry when I wake up?"
] | [
false
] | null | [
"You got it almost right, except for the whole \"get behind the contacts\" thing. The more important part is keeping the contacts themselves wet. ",
"Tears need to lubricate whatever surfaces the eyelid is contacting, whether it's the eye itself (if you're not wearing contacts) or the contact lens. This ensures s... | [
"The act of blinking physically forces the tears behind the contacts. While sleeping, you stop blinking and thus no water can get behind the contact."
] | [
"Thanks!"
] |
[
"What's currently the oldest living creature?"
] | [
false
] | null | [
"Depends on what you consider alive. There have been bacterial spores trapped in amber that were viable after 40 million years.",
"If you mean \"alive but not currently in some kind of stasis\" then probably weird seafloor or permafrost bacteria (can live tens of thousands or even millions of years).",
"If you ... | [
"I can only find a news article about a presentation at a conference, but it appears that the individual bacteria themselves are millions of years old and divide only once every 10,000 years. ",
"https://phys.org/news/2013-08-soil-beneath-ocean-harbor-bacteria.html"
] | [
"I cant recall of theres anything older and you could maybe argue this is cheating, but pando is actually an entire forest and one organism at the same time. Every quaking aspen in this forest is a clone and theyre all cknnected to 1 root system that is 80000 years old. The roots themselves are whats so old. The fo... |
[
"Are there alternatives to MRIs to do brain scans?"
] | [
false
] | I read that Helium is an important component to doing an MRI scan, but apparently the price of Helium is going to skyrocket because the amount of Helium that is going to be readily available will decrease. Is there any other technology to do brain scans without having to do an MRI? | [
"Let me start by assuring you that while MRIs use a good bit of helium at startup, it's stored cryogenically and very, very little is lost over time. Rising helium costs are not going to significantly affect the cost of MRIs.",
"Even if helium was completely unavailable, high temperature superconductors could be... | [
"Yes, atmospheric escape is the process by which helium is lost. The predicted rise in helium prices is due to the selling of helium reserves, and not because of some significant decrease in helium production."
] | [
"Gotcha. For the record I don't know what he's referring to either."
] |
[
"If we could transport to a planet very far away instantly, couldn’t we see how the earth was created and how life started?"
] | [
false
] | null | [
"Sure."
] | [
"Elaborate?"
] | [
"Light reaching a point 1000 light years away would have left the source 1000 years ago."
] |
[
"What will happen to a piece of wood, placed in a \"pot\"with no oxygen and then placed over a fire?"
] | [
false
] | also the same question but what if the "pot" was pressurised? | [
"That's basically a way to make charcoal. By starving the wood of oxygen you allow the moisture and volatile compounds to be burned off leaving you with a mostly pure carbon. It's important that it has some kind of vent though because the steam and volatile compounds will pressurize the container."
] | [
"That's basically a way to make charcoal. By starving the wood of oxygen you allow the moisture and volatile compounds to be burned off leaving you with a mostly pure carbon.",
"This is correct: in a closed vessel (pot) you would get pyrolysis (thermal decomposition), rather than combustion. If wood were pure ",... | [
"If the container can stand it, not much, but there could be some danger when you go to open the pot."
] |
[
"Are there any neutrons floating through the cosmos by themselves?"
] | [
false
] | A lonely proton, with a positive charge, would attract lonely electrons. This, my general chemistry classes have taught me, is why protons and electrons group together into atoms. But if we took a neutron out of an atom, and watched it, what would happen? What forces would act on it? Furthermore, could any of you exp... | [
"Neutrons decay into a proton, an electron, and an antineutrino after about 11 minutes. They have to be bound to other particles to be stable."
] | [
"*On average they decay after about 11 minutes. Some may decay in a millisecond, some may last millions of years. "
] | [
"Sure, neutrons decay... but if a neutron is ejected into interstellar space somewhere in the Universe more than once every ten minutes (which seems reasonable), then the answer is yes, there are plenty of neutrons floating through the cosmos.",
"What would happen to such a neutron? It could roll neatly into a nu... |
[
"Is this correct about mitosis and meiosis?"
] | [
false
] | [deleted] | [
"I don't understand how the haploid cells are supposed to under go meiosis to make more haploid cells",
"They don't - the only thing the haploid gametes can do to reproduce (at least in obligate diploids) is to pair up into diploid zygotes.",
"Is it when the egg meets the sperm and a diploid cell will form?",
... | [
"I think you have it down, but the way you phrased that makes me cautious. When a zygote is formed (the fusion of two haploid cells into a diploid cell) there is a new individual. In multicellular eukaryotes (like yourself) you get more cells and grow for mitosis. Meiosis is ",
"."
] | [
"I think you have it down, but the way you phrased that makes me cautious. When a zygote is formed (the fusion of two haploid cells into a diploid cell) there is a new individual. In multicellular eukaryotes (like yourself) you get more cells and grow for mitosis. Meiosis is ",
"."
] |
[
"What is the chemistry in an animal's coat is responsible for it's color?"
] | [
false
] | I understand that an animal's color is due to evolution and their genes, but there must be some chemical interaction that produces the color, isn't there? So there must be different interactions for every shade and color. What is that chemical interactions in blue-jays, chameleons, or tigers that gives them their chara... | [
"The colour we perceive in an object is due to the molecule's ",
"absorption",
" spectrum. Depending on what wavelength of light the molecule preferentially absorbs, we'll see different colours. This phenomenon is less a \"chemical\" interaction than a \"physical\" one.",
"It's the same with fur colours. The ... | [
"To add to that, some colors we see are due to pigments, such as melanins in mammal fur, for instance, but some of the colors we see on animals, such as butterflies and some birds are actually due to the microscopic structure of the surface being oriented such that certain wavelengths of light are visible. This is... | [
"The camouflage of animals is a ",
" fascinating phenomenon. See ",
"this video",
", where cephalopods rapidly change colours and patterns (as well as texture) in less than a second.",
"I actually did not know the mechanism behind this, but after some research, I found this ",
"article",
" in Scientific... |
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