title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Is there a formula to explain the ever expanding space?"
] | [
false
] | null | [
"You're looking for the Friedmann Equations."
] | [
"Would you point me to the correct one, they all confuse me a little :) "
] | [
"You probably want either or both of the first two under the \"equations\" section: ",
"https://en.wikipedia.org/wiki/Friedmann_equations"
] |
[
"How did our distant ancestors cut umbilical cords, like the time before knives. Maybe a sharp rock?"
] | [
false
] | null | [
"Does that environment really need to be simulated?",
"Not that I doubt you, but I'm curious because some humans are quite adept at living in cold climates, compared to the warm environment you're describing."
] | [
"Does that environment really need to be simulated?",
"Not that I doubt you, but I'm curious because some humans are quite adept at living in cold climates, compared to the warm environment you're describing."
] | [
"Do they just have to hang around attached to a placenta until then, like they’re the Orphan of Kos?"
] |
[
"When something is thrown at us or unexpectedly falls, how can the brain calculate exactly where to position the hand to catch it, sometimes in milliseconds?"
] | [
false
] | null | [
"The brain is basically a very powerful computer and can calculate how something is going to move as well as working out how to move your hand to catch something. Some of this is learned - how things fall but a lot of it is calculation. If you were to do it on paper it would be some very complicated calculus.",
"... | [
"I'm very curious to hear the answer to this. I assume it has to do with reflexes but i think that reflexes vary from person to person. ",
"So as a follow up question, I'd like to know why some people have better reflexes than others."
] | [
"The brain is basically a very powerful computer",
"That's a model, it's not necessarily true. For most purposes this is a useful way to think about the brain's workings. But one shouldn't be seduced into thinking that brains = computers. ",
"the catcher will move and adjust their speed so that the trajectory o... |
[
"How can a Boltzmann brain just arise from random entropy?"
] | [
false
] | This is without a doubt one of the strangest physics things I've ever found. All I can find is this small and either very technical or very whimsical web pages. Secondary question: Is the Boltzmann brain theory held in any particular regard today? | [
"Searched",
"Relevant ",
"discussion",
"Original question by ",
"bryce1234",
"Could some explain the Boltzmann brain hypothesis?",
"Relevant comment courtesy ",
"Hairy_Hareng",
"Ok. I have read the wikipedia page and I have a little bit of knowledge of probabilities and entropy.",
"It seems to me ... | [
"The idea is that your random gas molecules will bounce around randomly, and eventually, by sheer chance, line up in a configuration that an external observer might identify as sentient (or some other low entropy configuration). One such configuration, of course, is the universe we see today, with us in it. Of cour... | [
"Thanks my robotic friend. What I take away from this is that the theory is not something anyone really takes seriously anymore, but I'm still unsure how a bunch of random gases becomes sentient."
] |
[
"If there is no water on Mars, what creates the formations on the Martian landscape that look so similar to formations on Earth such as the Grand Canyon?"
] | [
false
] | Looking at the photos from Curiosity and other Mars rovers, I'm struck by the apparent similarity between the rock formations on Mars and places we have on earth specifically the Grand Canyon in the US. Having visited the Grand Canyon and being in awe that "water could create such a giant hole in the earth" it strikes... | [
"At this point, we're almost certain that Mars once had liquid water on its surface...",
". You simply don't get dendritic erosion features like ",
"these",
" without some kind of liquid doing the erosion - and water is the obvious choice here.",
"(Side note: the really big valleys, in particular Valles Mar... | [
"Common theory is it once had liquid water, much like earth. Due to when the core solidified/the tectonic plates merged, it either evaporated or solidified into ice(found at the poles)."
] | [
"You don't get ravines, gullies, and dried lake beds/river systems with just sandblasting. Sure, wind may cause erosion, but water is the number 1 cause of erosion in landforms, and is a much more influential factor than wind. Since water is such a great solvent, it can flow through channels and pick up sediments, ... |
[
"Are there any land macro-animals (ignoring insects etc) that have a population in the billions like humans?"
] | [
false
] | null | [
"19 billion",
"\"Up to 7 billion\"",
"\"which, everyone agrees, outnumber us — but no one seems eager to count\"",
"\"About the same as rats\"",
"1.4 billion",
"\"About 1 billion\""
] | [
"I find it interesting that 3 of those categories are specifically bred in large numbers for human consumption. I wonder what the \"natural\" numbers would be, if we hadn't domesticated them?"
] | [
"Thank you."
] |
[
"What are we seeing when an aircraft breaks the sound barrier?"
] | [
false
] | Whenever you see a picture of an aircraft breaking the sound barrier, you see a cone of smoke or vapor around it, what the heck is that? | [
"Those pictures are not necessarily the aircraft breaking the sound barrier, just that the conditions in the flow cause the water vapor in the air to condense."
] | [
"To add on, it usually occurs when some parts of the flow around the aircraft have become supersonic while other remain subsonic. "
] | [
"its water vapor in the air condensing. ",
"when the shock wave from breaking the sonic barrier decompresses the air gets considerably cooler from the expansion and it causes the water in the air to condense. "
] |
[
"Does the Moon's gravity leave any geological traces that are identifiable in Earth's strata over time?"
] | [
false
] | I mean, are there any geologic markers on Earth that have been identified to track the historical path of the Moon around the Earth, to identify when the Earth first captured the Moon? | [
"Two points, first a clarification and then an answer to the meat of the question.",
" The Earth did not \"capture\" the Moon. The standard model is that a proto-Earth, around 90% of the mass of the current Earth, was struck by a Mars size impactor, usually called Theia. (e.g., ",
"O'Neill, 1991a",
", ",
"... | [
"There remains ambiguity about the exact timing, but a variety of different approaches suggest the moon-forming impact happened around 100 +/- 50 million years after the beginning of condensation of the solar system. Some of these were already cited above (e.g., Jacobson et al., 2014, Young et al., 2016), but there... | [
"In some ways I suppose one could say that the moon is the geological record of the impact."
] |
[
"Question on Length Contraction"
] | [
false
] | My current understanding of length contraction is best represented by the ladder & barn scenario. A man has to bring a 5m long ladder into a barn that is 4m long. A stationary bystander watches the man travel at .6c, and the ladder fits into the barn due to length contraction. However, from the reference frame of the m... | [
"Only events have to be the same in all frames of reference. \n\"The ladder fits in the barn\" is not an event. \"The front of the ladder leaves the barn\" and \"the tail of the ladder enters the barn\" are two events that are separated spatially.",
"\nThus, it does not violate relativity if they happen at the sa... | [
"Yes, that's correct. This does not violate any laws of physics, but it does violate out intuition about the simultaneity of events.",
"The statement \"the ladder fits into the barn\" can be rephrased in terms of spacetime events as \"the front of the ladder leaving the barn (event 1) occurs after the back of the... | [
"Thanks! This makes sense"
] |
[
"If casein gives cheese its structure, what's the protein that gives tofu its structure?"
] | [
false
] | null | [
"You're correct, I should have said \"non-enzymatic\". For tofu they use salts alone (AFAIK) to coagulate the soy milk into \"curds\". "
] | [
"Cheese doesn't get its \"structure\" from casein per se, but rather from chemical transformations and coagulation of protein suspensions (mostly casein) in water that eventually gives you a solid water-insoluble material. The same thing happens in tofu-making but AFAIK the coagulation is purely chemical (no enzyme... | [
"Cheese doesn't get its \"structure\" from casein per se, but rather from chemical transformations and coagulation of protein suspensions (mostly casein) in water that eventually gives you a solid water-insoluble material. The same thing happens in tofu-making but AFAIK the coagulation is ",
" [emphasis mine] are... |
[
"Is it true that over the course of billions of years, the moon's revolutions around the Earth will cause the Earth's rotation to slow, giving us more hours in the day?"
] | [
false
] | I seem to remember that I heard back in elementary school that something to do with the Moon's revolution is causing the Earth to slow down and in a few million (or billion, I heard this a long time ago) years we will have more than 24 hours in a single Earth day? | [
"Fair enough. I'm an astronomer, so anything that happens in less than a billion years is fast!"
] | [
"Yes. Tidal friction is (very) slowly slowing the Earth's rotation to match the moon's orbital period. At the same time, the moon is gaining the Earth's lost rotational momentum, and being flung out to space (at a rate of a few centimeters a year). Neither of these things will happen fully before the sun dies, but ... | [
"The process is slow on human timescales, but it's not ",
" slow. Fun fact, back when dinosaurs were around the length of a day was 21-23 hours! Also the moon was closer and would've looked even more impressive at night.",
"The current rate is that the day gets longer by a couple milliseconds every century."
] |
[
"If 80% of matter is dark matter, how do they send probes to mars without taking dark matter into account?"
] | [
false
] | [deleted] | [
"Dark matter in our area has a relatively uniform density and a very low density, it doesn't clump up like regular matter does. Like driving a car, yes the air is there, but we don't really care about it, unlike the trees which have a significant impact on where we drive.",
"And looking at some numbers, let's say... | [
"Dark Matter is called 'Dark' because it interacts so weakly with regular old matter/forces. The effect is negligible unless you're describing the motion/shape of very large/gravitationally strong object, like galaxies."
] | [
"It's right, we only know of its existence because of gravitational effects. That means it doesn't interact nongravitationally (or it interacts only weakly) with regular matter, because if it did, we could have detected it by other means. This means that dark matter particles would normally pass through ordinary ma... |
[
"Why aren't animals with bigger brains smarter?"
] | [
false
] | According to this wiki article: Elephants and whales have more neurons than us. So why aren't they smarter? | [
"Same reason an amputee doesn't get smarter.",
"Brains are designed by evolution to control a body of a certain size.",
"A genetic quirk that makes someone smaller doesn't change that basic design. "
] | [
"If you normalise to body mass it becomes much clearer. See the plot here:",
"http://www.rpi.edu/~eglash/eglash.dir/ethnic.dir/race/eq.gif",
"Above the line is smarter than average, and vise-versa. ",
"The idea is, I think, that a larger body simply takes more processing power to run than a smaller one, and y... | [
"The amount of prefrontal cortex is also an important factor. ",
"I did a quick google search, and the first article that popped up is from my University! It's pretty neat, click ",
"here"
] |
[
"Is there a physical limit to the quality of image sensors?"
] | [
false
] | null | [
"The answer to your question depends on what you mean by \"quality.\" If by quality you mean angular resolution (i.e. the smallest feature you can image), then yes. The ultimate angular resolution of an image is limited by a process known as diffraction. An imaging system that can image at its minimum angular re... | [
"Most of the diffraction-limited applications can be improved with a physically larger sensor (your cell phone is only so good, but if you build to 10 meters in diameter, it's a telescope and works much better). The issue with the larger ones is noise, that is as you build it larger you force the light to be spread... | [
"Yes. I'm not going to give a sharp bound, but there definitely exists one: for example, you could be collecting and recording every single photon that arrives perfectly. Any sensor will necessarily be no better than this, so there exists some kind of upper limit. "
] |
[
"Do scientists have the knowledge and/or capability to manipulate genes?"
] | [
false
] | There is an enzyme in animals and humans called , which breaks down uric acid. However, the gene for urate oxidase in humans is non-functional. Do we have the technology currently to "fix" this gene and somehow activate it? | [
"Yes, we do. Work related to the manipulation of genes is being performed fairly frequently in labs. For instance, I finished a semester-long research project doing just that in nematodes, and I'm still working on my undergrad!",
"The main issue with genetic manipulation is that while we have made many significan... | [
"Yes, we are still learning a lot and are still pretty early in it. However, it's a lot more common then you think. I was talking to a Chemical Engineering buddy over at Kodak, and he was telling me how they genetically make bacteria who's byproduct is used to make the ink in your printer. ",
"The problem wit... | [
"We do have the technology to fix the gene, but it's dangerous; we don't have the understanding to be sure it won't screw something up in a way we don't understand. In simple organisms (bacteria, or well-studied plants or worms) we do this kind of thing all the time. Of course, a lot of the time we end up with some... |
[
"Do the bubbles on cappuccino insulate it? Will it cool faster if I sip them from the top of my coffee?"
] | [
false
] | I've always assumed that the bubbles on top of a cappuccino have an insulating effect, meaning that it stays hot for longer. But recently I've started to theorise that the top surface of the bubbles might have a higher surface area than plain coffee meaning that there is more evaporation and therefore faster cooling. | [
"basically you are correct. The air that is trapped in the bubbles has a MUCH lower convection coefficient than your coffee does. It DOES insulate your coffee but by a very small amount. I would do the math and all right now but I don't have any paper and pencil. I would also need to know the thickness of a bubble ... | [
"My girlfriend and I were discussing this about bubble bath the other day, we decided to get a USB thermometer and do science! Yay! Still waiting for it to be delivered, I'll publish graphs in a few weeks"
] | [
"to add on to this great explanation, the reason why styrofoam is a great insulator is because it has air trapped in it. Why is this good? Because air is the best insulator there is (apart from a total vacuum) but only when it's not moving. Those bubbles trap the air and minimize the circulation of the air and that... |
[
"How fast was the meteorite that landed in Russia traveling?"
] | [
false
] | null | [
"Russian Academy of Science have estimated it as 33,000 kph on entering the atmosphere. ",
"http://www.bbc.co.uk/news/world-europe-21468116",
"That 'sonic boom' may have been the shockwave triggered when the meteor hit the atmosphere (or a denser layer within the atmosphere), hence the long travel time before a... | [
"Are you referring to the meteorite that landed over Chelyabinsk? If so, the Russian Academy of Sciences ",
"estimated that",
" the meteorite weighed about 10 tons and:",
"\" entered the Earth's atmosphere at a speed of at least 54,000 kph (33,000 mph), shattering about 30-50 km (18-32 miles) above ground.\""... | [
"about 33,000 km/ph or for those of you that still haven't caught up with the 20th century its 20505.25 m/ph."
] |
[
"How do snow leopards survive huge falls without alot of damage or death?"
] | [
false
] | Hey guys, I was looking at a documentary about big cats and was fascinated by the hunting behavior of snow leopards. There's a lot of footage of them hunting and plummeting 100+ meters from mountains and surviving unscathed, while almost any other animal would break in half. What is the science behind them taking blows... | [
"Leopards, lynx, house cats, and most other felines have several defining features that allow them to fall and land from great distances.",
"The main one of which is that they have a lot of skin and little mass, most of this excess skin is found in between the limbs and torso (That why cats look like they wear ba... | [
"I knew cats could fall for great distances, but not that the Snow Leopard had extra adaptations that make it even more fall resistant. Thank you for your answer."
] | [
"You’re welcome! I imagine the impact resistance is of value to a creature that spends 90% of its day on cliffs."
] |
[
"Does temperature affect how quickly a person would bleed out?"
] | [
false
] | If two people of the same age and health were to sustain the exact same stab wound to the chest, but one in temperatures below freezing and the other in a hotter climate who would die faster? | [
"There is a saying in emergency medicine that goes \"they aren't dead until they are warm and dead\".",
"It is true that if you were stabbed and bled out while you were hypothermic it would take longer for your cells to die (because your metabolism is slower), which would theoretically give you more time to bring... | [
"I won't comment on a body below freezing, but patient's who are hypothermic have a much higher morbidity in trauma/hemorrhage. This is due to the \"lethal triad.\" The blood coagulation system is impaired in the setting of acidosis, coagulopathy, and hypothermia. Thus, hypothermic patients do not clot as well. "
] | [
"Theoretically, the warm one would bleed out slightly quicker because the blood would be thinner/less viscous at a warmer temperature, thus flowing more quickly. Additionally, blood vessels tend to constrict, somewhat ",
"powerfully",
", when exposed to cold conditions. As a caveat to the blood constriction, th... |
[
"Why are kids these days allergic to everything?"
] | [
false
] | null | [
"I've removed your question because it's asking for an explanation of an assumption, without providing evidence for existence of the assumption. If you want to repost, an acceptable re-phrase would be something like, \n\"Has there been an increase in the prevalence of allergies?\" and the text can then ask, \"I'm ... | [
"Thanks doc. That was my first post to AskScience. "
] | [
"No problem. Welcome to AS, we're glad to have you here (even though you did post in AS 20 days ago :)... I won't tell). Let me know if you have other questions."
] |
[
"How do insects climb onto walls and ceilings?"
] | [
false
] | I wonder how insects such as spiders and most bugs are able to stick themselves on to walls & ceilings | [
"baloo_the_bear explained it well enough, but I don't think that's the only mechanism that works. Some lizards are able to climb walls because they have millions of tiny little hairs (or hairlike structures) on their feet.",
"They don't use glue or something, it's just a neat physical effect called van-der-Waals ... | [
"Could we scale these processes up and allow larger items to do the same? Or is there an upper limit where the force can't carry so much weight?"
] | [
"We can, and we do.",
"http://www.stanford.edu/group/mota/education/Physics%2087N%20Final%20Projects/Group%20Gamma/gecko.htm",
"http://www.popsci.com/scitech/article/2008-04/gecko-tech"
] |
[
"Would covering the roof of a building with a reflective shade material cool it by a noticeable amount?"
] | [
false
] | This is what I mean: Would putting something like that on a roof make any difference? Would mounting it a few inches above the roof make any difference? | [
"This would make a big difference on a sunny day. This would change the ",
"albedo",
" of your house, meaning that less sunlight is absorbed by your house, and thus less radiative heat actually warms your house. One proof of this is that houses in hot climates in Europe are painted white allot, this helps to ke... | [
"An interesting phenomenon of this is that in some cities such as Philadelphia, PA, you can view economic areas in aerial photographs via the white roof painting that has been done to help with the summer heat."
] | [
"would it make a difference if the shade material just laid on the house, or was suspended a couple of inches from it?"
] |
[
"Why can't we precisely compute orbits?"
] | [
false
] | I know some of it is due to relativistic effects, but what natural forces/processes lead to the uncertainty? | [
"What makes you think we cannot? We can predict solar eclipses 1000 years into the future easily - ",
"here is a table for the 30th century",
".",
"The accuracy of the predictions depends on a lot of things, but mainly on time. Over time even small uncertainties in initial parameters add up to larger uncertai... | [
"Well, of course you can never reach mathematical exactness if your calculation depends on measurement values."
] | [
"That doesn't play a relevant role for millions of years unless you consider comets or similar objects with planet-crossing orbits."
] |
[
"What is the minimum amount of time needed to take a water molecule from boiling point to freezing point?"
] | [
false
] | [deleted] | [
"Note that temperature is only well defined when talking about a large number of particles; one single water molecule doesn't have a boiling or freezing point."
] | [
"You can drop a solution of water from boiling to freezing instantly using the triple point."
] | [
"That's for convection, but there are other methods as well - laser cooling, for example."
] |
[
"Can simple invertebrates like snails feel pain? How can we know for sure either way?"
] | [
false
] | Thought I'd ask this question again, it was asked 5 years ago in this thread "Do insects and other small animals feel pain? How do we know?" . It got some very good replies. Especially from . I'll paste some of it here, but please read the whole thing, it's amazing. Let's start off by saying that this question has been... | [
"In some studies with mealworms, when touched with a hot metal rod, they would cower away. This concludes that \"hot, no touchy\" is a basic instinct in this creatures as it is in us. ",
"However, we can't say they feel \"pain\" as we do, since we have specific areas in the brain that process pain. With infinitel... | [
"Former pain researcher, though I used rats. ",
"This sounds really technical & legalistic, and other people with different training may have a different answers, but this is how I was trained.",
"We used various methods to measure analgesia. In my field, because you’d need language to report it, pain (or emoti... | [
"Pain is an emergency signal the brain uses to control our behavior in order to increase our survival probability. It can be infered that most lifeforms that need/have this type of response can actually \"feel\" it."
] |
[
"Does electromagnetic spectrum goes to infinity?"
] | [
false
] | And can we discover something even higher than gamma-rays? | [
"Since I answered the same question yesterday, I'm just going to copy-paste what I said there - note this is talking about how high the energy of photons can go, but the same as saying how high the frequency of the EM wave is. ",
".",
"Answer:",
"We actually don't know. The highest energy photons detected ar... | [
"Physics kind of break down when a photons Schwarzschild radius exceeds its wavelength (roughly at the size of the Planck length, 10",
" m). ",
"At the other end if a photons wavelength is larger than the diameter of the observable universe, it wouldn't be detectable.",
"But one could argue that in a theoreti... | [
"Shouldn't there at least be some theoretical limits based on what we think we know about largest and shortest possible distances, the total energy size and age of the universe etc?"
] |
[
"Why did this orange juice residue crack into rectangles? [from /r/mildlyinteresting]"
] | [
false
] | It makes sense that the pieces would be smaller on the outside, where the layer of juice was thinner, but why are the pieces so perfectly rectangular? . It reminded me of the post from a few months ago. | [
"There was an article in Scientific American a decade ago or so (can't find it) that delved into why mud cracks form right angles where they meet. It has to do with stress relief -- if there's an existing crack, say, N-S, the stress in the E-W direction has already been relieved. When another crack propagates into... | [
"My best guess is that because of the high sugar content and other crystalline ingredients in the orange juice, after drying these particles formed into a generally uniform shape according to their molecular structures. ",
"Basically like how regular ol' crystals form, the individual particle's shapes will aff... | [
"Those don't look like single crystals. The shapes aren't all that uniform, and there is no evidence of ",
"preferential crystallization",
" of pure compounds (try freezing some soda: you'll see pure ice crystals around the edge of the container, with the impurities (sugar, colorants, etc.) being pushed into t... |
[
"Why are deuterium and Tritium isotopes of hydrogen, but not their own element?"
] | [
false
] | null | [
"Because they have one proton in the nucleus."
] | [
"But why does that matter? Hydrogen has no neutrons but Deuterium and Tritium do, shouldn't that be enough to classify as a new element?"
] | [
"The element is defined by the number of protons only."
] |
[
"When you \"lose your voice\" from a cold or the flu, what is actually the physiological cause?"
] | [
false
] | People sometimes grow extremely hoarse, even to the point of "losing their voice" when they are ill with upper respiratory infections. I'm a bit ashamed to say that, even with a degree in speech and hearing, I really don't know how to explain this phenomenon. Is it due to secretions coating the vocal folds? Is it due t... | [
"Laryngitis is an inflammation of the voice box (larynx).\n",
"http://en.wikipedia.org/wiki/Laryngitis",
"Vocal cords are muscle in the larynx. When you talk, air going past the vocal cords vibrate to make your voice. So when your vocal cords are inflamed or swollen, your voice is changed (hoarseness or raspine... | [
"People can still talk (albeit with altered voice) with nodules on their vocal folds. It seems counter-intuitive that inflammation alone would be able to completely \"lose\" someone's voice. ",
"At any rate, what does the inflammation ",
" to cause a person to lose their voice I wonder? Does it make the vocal f... | [
"It's the swelling. Inflammation causes vasodilation in the tissue, so fluid and and cells can permeate it. This causes swelling, and the change in shape of the vocal chords changes the sounds it can produce, or make you lose your voice"
] |
[
"How are antibodies transferred to a newborn through colostrum? Why can't I drink antibodies instead of being vaccinated?"
] | [
false
] | null | [
"I'm a PhD in Molecular Medicine and Genetics.",
"Antibodies get transferred to the baby during the last three months of gestation, across the placenta. Like cows (and pigs and lots of other mammals), human babies have porous stomachs that allow the antibodies from breast milk to pass into their bodies.",
"Unf... | [
"From the ",
"Wikipedia",
" page on colostrum:",
"This oral transfer of immunity can occur because the newborn's stomach is porous. This means that large proteins (such as antibodies) can pass through the stomach wall. The newborn animal must receive colostrum within 6 hours of being born for maximal transfer... | [
"Yeah, now the only thing that remains is if this immunity is just temporary or not..."
] |
[
"How is it possible to filter out all the waste, drugs, and bodily fluids that end up being flushed down the toilet, and come out with such clean potable water?"
] | [
false
] | There's so many things that people throw down the drain and toilet like food, human waste, drugs; I guess the simple answer is filters, but how strong of filters or counter chemicals do we need to have in order to squeeze out clean water? | [
"It’s not the filters you are thinking of but biofilters. Wastewater is aerobically and anaerobically digested by microorganisms at wastewater treatment plants. There bacteria and fungi etc. break down drugs and chemicals that are carbon based. Heavy metal type wastes fall out and are removed as sewage sludge."
... | [
"Wastewater treatment is a multi-step process. The first step is a simple mechanical cleaning - screens filter out any larger debris that would mess up the later stages, and settling basins are used to let sand and other dense suspended solids sink to the bottom, and let oil and other less dense stuff float to the ... | [
"And then happily dumped into nearby rivers and streams for the local fauna to merrily drink or live in. Yay three-eyed fish and two-headed toads! ",
"/S"
] |
[
"We've cloned sheep. We've cloned a lot of mice. Some folks want to clone mammoths. How hard is it to clone a tree?"
] | [
false
] | I was reading recently about a species of mahogany that yielded the finest furniture ever made--so fine, in fact, that it went extinct from over-use. With all the recent talk about resurrecting the mammoth, it struck me that bringing back a species of tree, a much simpler organism which has many close extant relatives ... | [
"Plants are easy to clone. You just take a cutting of it, shove it in the ground, and boom, clone. Cloning from straight DNA in plants is vastly harder.",
"Plants are NOT simple organisms, no matter how boring they look. They are just as complex as humans in just about every metric you pick - genome size, number ... | [
"Some ferns have THOUSANDS of chromosomes in each cell."
] | [
"We have been cloning plants for centuries, even before we knew what cloning was.",
"But cloning from ",
" tissue can be a problem."
] |
[
"Why is methionine always the \"start\" codon for proteins?"
] | [
false
] | Taking a couple biology classes and both have mentioned that methionine (AUG) is the first codon for proteins, but I haven't found anywhere in the text books or online as to why this specific sequence of nucleotides is always what starts a protein. My microbiology instructor didn't know either. I figured Reddit would p... | [
"Interestingly, AUG is actually not the only start codon, though it is by far the most popular. ",
"Alternative start codons",
" include GUG and UUG. The most interesting thing is that these alternative codons are still translated as Met, regardless of what they typically code for, by using a special start codo... | [
"The tRNA that carries methionine to the ribosome contains a CAU anticodon that recognizes the AUG start codon. This tRNA also associates with several translational initiation factors that bind to the 5' mRNA cap in eukaryotes and promotes the formation of a pre-initiation complex with the small ribosomal subunit. ... | [
"It could be just chance. Perhaps it was just coincidence that in the early origins of life, methionine was chosen to be the start codon. ",
"And since it works and without any significant selection pressure to change this, it was conserved and passed through the phylogenetic tree. ",
"This is kind of similar t... |
[
"When in tense or scary situations, why does the heart beat faster? Does increased blood flow make you more alert or capable?"
] | [
false
] | The hormone adrenaline causes the increase in heart rate, but why? | [
"The nervous system has a few branches; one of the branches of the central nervous system is the sympathetic division. It is autonomic, meaning it is involuntary, and involved in the \"fight or flight\" reactions we have. In scary situations, this branch of the nervous system is active and causes several physiologi... | [
"Does increased blood flow make you more alert or capable?",
"It makes a big difference for muscle function. Increased blood flow brings more oxygen to the muscles, which lets them work harder for a longer time before becoming fatigued. ",
"If you're about to get into a fight or run away from a predator, improv... | [
"I see, thanks!"
] |
[
"How do scientists know how much dark matter a galaxy has or doesn't have?"
] | [
false
] | null | [
"You take a galaxy and measure the rotation speeds of the stars. When you plot them on a graph of orbital speed Vs their radial distance, you'll see that it doesn't add up. There should be more mass present to account for all that speed. Then you figure out how much mass should be there for the stars to be going th... | [
"It’s worth mentioning we can also just take ",
"a picture of dark matter",
" with a telescope to measure it. Gravity causes visible red shifts, so all we had to do was find a galactic collision in the sky and the dark matter would slide past the regular matter due to how weak it interacts before condensing bac... | [
"Hey DudeFocus!",
"So the initial observations which pointed to dark matter were made by an astronomer called Fritz Zwicky in the 1930s. He was looking at a cluster of galaxies known as the Coma Cluster took measurements on how much matter there was based on the light he observed, and how much matter must be ther... |
[
"Why aren't the *sub*species of brassica rapa just considered different *species*?"
] | [
false
] | I guess the question is, what's the difference between subspecies and species, at least in the plant world? there even a clear distinction? | [
"One really important thing to understand is that ",
" difference (IE, difference in shape) has surprisingly little direct relationship with ",
" difference. You can change a very few genes and produce a plant that looks totally different. Or you can change a lot of genes and produce a plant that looks almost... | [
"For the record broccoli, kale, cabbage, kohlrabi, cauliflower, Brussels sprouts, and collards are all the same species: ",
".",
" (in OPs title) include white turnips, box choy, tatsoi, mizuna, Chinese/Napa cabbage, and broccoli raab."
] | [
"The concept of species existed before we knew of genetics. Back then, it was mostly based on morphology (do they look different) and whether you could observe interbreeding.",
"Now, with the ability to sequence genomes, species concepts can also be investigated using for example the phylogenetic species concept ... |
[
"Is there something genetically or physiologically that makes someone a \"morning person\" vs not?"
] | [
false
] | null | [
"A similar question was asked a while ago ( ",
"What makes one a \"morning person\"? Is it possible to condition yourself to be this way?",
" ). Here's a copy-paste of what I replied then: ",
"Your natural body rhythms are largely determined by your T (tau), or circadian period. Basically this means, if we l... | [
"Yes, it's genetic in ",
"Chronomedicine",
" it's generally accepted that people are born with tendencies to sleep and wake at certain times. ",
"Further (scientific) reading for the layman: ",
"http://www.amazon.com/Body-Clock-Guide-Better-Health/dp/0805056629/ref=sr_1_2?s=books&ie=UTF8&qid=1351787725&sr=1... | [
"I'm not going to give you a source on this one (because I'm at work--in a lab that studies circadian rhythms!), but I remember it being mentioned in a lecture I attended by a guy who does this stuff in humans; in fact I'm pretty sure this exact question was asked. His theory is that it's because a certain persona... |
[
"What happens to an airplane if it gets struck by a lightning bolt?"
] | [
false
] | [deleted] | [
"not much typically, unless it's a carbon composite. The aluminum body on most airplanes routes the lighting around the fuselage and allows the bolt to continue on its merry way."
] | [
"Its true. Bill nye said it in his lighting show"
] | [
"Most airliners get hit at least once a year"
] |
[
"Is plant growth ever limited by CO2 availability?"
] | [
false
] | First, I'm not a global warming denier! I know that this reasoning was advanced by oil companies to put a positive spin on CO2 emissions. It's amazing what a small part -- 0.039% -- of the atmosphere is CO2, especially after reading on Reddit that most of the dry mass of plants is pulled out of the atmosphere, not the ... | [
"The problem with that is that while plants might grow faster, they don't necessarily live any longer. So if you're talking about crops, or grasses on the great plains, they are still going to be harvested and rot every year, so that CO2 goes right back into the atmosphere. The ocean ecosystem is probably not CO2... | [
"Quick correction - the atmosphere is ",
" CO2, not 0.39%. "
] | [
"Yes. It is actually thought that plants evolved during a period in which more CO2 was readily available. Some plants have even developed methods for coping with lower levels of CO2. Specifically, ",
"C4 Fixation",
" is thought to have developed more recently (in evolutionary terms)to combat waste caused by ... |
[
"what is the highest temperature achieved by man?"
] | [
false
] | i was watching Vsause's video where the commentator said that the LHC reached a temperature of 1 exakelvin (1 x 10 C). on the wiki page of temperature, it says that only a temp of 10 trillion K was produced by the LHC (also the source page cannot be found to verify that). the Huffington Post says the highest temperatur... | [
"This confusion likely came from a ",
"short scale/long scale",
" mixup - 10",
" is a trillion on one, but a million trillion in the more common short scale used in the US.",
"So, yes, the LHC can routinely get up into the 10",
" K range, and since the LHC is in Switzerland, they'll call this a trillion k... | [
"This is absolutely correct. ",
"The paper cited quotes what I consider the most precise measurement of the temperature, which is 1.8x10",
" K.",
"However, this is the temperature at what is called \"freeze-out\", when the quark-gluon plasma produced in a lead-lead collision has expanded and cooled enough to ... | [
"10",
" is much more reasonable than 10",
" based on everything I've read. ",
"This paper",
" quotes a temperature of 156 MeV, which when divided by the Boltzmann constant yields 1.8x10",
" K. ",
"An order of magnitude calculation, 7 TeV divided by the Boltzman constant is ~10",
" K, so maybe that's w... |
[
"When was the last time the moon was hit by a large enough meteroid that it would have been visible from earth?"
] | [
false
] | null | [
"There are periodic flashes on the moon (a few have even been recorded) that are thought to be from meteor strikes. Unfortunately, because the moon lacks and atmosphere, we do not get as big of a fireworks show as we do when meteors hit the Earth. This means we don't see most of the ones that impact even though th... | [
"Right the photos of flashes on the moon are so notable because they are so rare even though the moon is observed and recorded ~continuosly by humanity.",
"If we could actually see all the impacts the moon gets that are too small to make noticable flashes it would be quite the show, day in and out. Unfortunately ... | [
"Here",
" is one from March 17th, 2013. The flash was imaged from earth, and LRO was able to image the resulting crater, showing both before and after the impact."
] |
[
"Does someone who is \"in shape\" run a mile using less ATP than someone who is not \"in shape\"? Why?"
] | [
false
] | null | [
"It depends on a lot of factors. To simplify things we'll assume identical weight and body composition between the two people, because different masses will require different amounts of work to move the same distance. So now we have two different people of identical weight and body composition running a mile, one... | [
"/u/codyish",
" wrote ",
"at a pace at which running is more comfortable than walking",
"Note the \"at a pace at which\". What is meant, I think, is this: Consider a normal walking pace. Walking is then more comfortable than running at that pace. ",
"Now consider a faster pace, at which it is difficult to w... | [
"What do you mean by \"running is more comfortable than walking\"? "
] |
[
"Why is it hottest after summer solstice, but not before?"
] | [
false
] | Where I live (Pacific NW) it is always cool and raining until the end of June, but then gets into the high 90's+ from July till September. Shouldn't it be hotter equally before and after the solstice? | [
"http://en.wikipedia.org/wiki/Seasonal_lag"
] | [
"The Solstice is the peak in the ",
" of energy arriving in the Northern Hemisphere. The land temperature is determined by the amount of ",
" energy. That's the difference.",
"So long as the rate of energy arriving is higher than the rate of energy leaving (being radiated back into space), the temperature of ... | [
"Makes sense, thank you both for excellent answers."
] |
[
"Why does the plastic bag 'trick' work with magnetic strips on Credit cards?"
] | [
false
] | [deleted] | [
"The card reader has a small induction coil that detects a succession of magnetic and non-magnetic zones in the card’s magnetic stripe. When the card is pulled through the reader, each magnetised zone makes a small electrical pulse as it passes the coil. The zones are arranged to encode the data needed to complete ... | [
"I once contacted a card manufacturer about this. The tech told me the reason that it works is that card readers have an automatic gain control, that is they adjust the amount of signal the cards reader amplifies from the weak voltage the reader head produces when you swipe the card. When you use the the bag or tap... | [
"I believe it will."
] |
[
"Do fat people have strong hearts?"
] | [
false
] | Do fat/obese people have stronger hearts than those thinner than them? I know strong is a vague term, but I'm not sure how to explain it. For example, if a person weighed 300 pounds, and lost 100 pounds, would they subsequently have increased blood volume capacity and faster heart rate? | [
"I have been told by others on here that fat/obese people would actually be very healthy (perhaps healthier than average people) with strong muscular frames from years of carrying excess weight if they decided to lose the weight. ",
"It's like wearing 30-50lbs training weights all day, every day all over your bod... | [
"Yes and no. For some one who is extremely obese (500 lbs and up) the heart thickens to allow for stronger contractions. if this person were to lose weight (say down to 350 lbs) the heart would remain thick but would pulse less. So yes they have \"stronger\" hearts than an average sized person, but no the heart is ... | [
"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1767922/"
] |
[
"Do magnetic and/or electric field have any influence on time and space?"
] | [
false
] | According to Einstein, gravity has influence on space and time. Does magnetic field have influence on time and space? Does electric field have influence on time and space? | [
"As other people have pointed out, the answer is yes, but there’s something in the way you phrased the question I want to focus on. You said that gravity curves spacetime, and wondered if other forces do as well.",
"It’s much more accurate to think of matter and energy as curving spacetime, and this effect is ",
... | [
"Yes, all energy contributes to the stress-energy tensor and the curvature of space-time so that includes energy in the electric and magnetic fields"
] | [
"I'll provide two different explanations in case you find one more helpful than the other. The first one is mine, and the second one is quoted below from a Scientific American article. While mine speaks a little bit more loosely with certain definitions, it has been a useful way for me to think about some things.",... |
[
"Is the \"record meteor\" related to the \"record asteroid\"?"
] | [
false
] | null | [
"It is more likely a coincidence than crashing Slitheen vessel, and it is probably even odds with being related to the asteroid. The problem is that if too large a chunk of the asteroid broke off, we would notice a difference in size. If too small a chunk broke off (that we couldn't see), it would disintegrate full... | [
"This is a very poor answer. The OP didn't at all state that the event required meteorites to be relevant and there are many meteorites much too small to detect that impact the ground every day. Where do you get 50% probability from?",
"edit: Also jokes aren't allowed on askScience."
] | [
"In part. You can also estimate it by the impact crater left."
] |
[
"For Astronomy/Physics buffs: questions about black holes, time travel, and the information paradox. Huge post."
] | [
false
] | [deleted] | [
"I have no credentials, so feel free to correct any errors I have made. Also, my responses are limited to my own knowledge, but the topics you've brought up are interesting to me. ",
"What does it mean to go to \"another time\"? It seems like that phrase presupposes that some overarching mechanism keeps track o... | [
"breakbread covered a lot of it but I'll just address #4.",
"In string theory, strings are fundamental so not really made of anything. Same as electrons: they're not made of anything, just fundamental. Strings are part of a wider concept called branes, which I don't really understand.",
"There's no experimental... | [
"Thank you very much for your thorough reply! "
] |
[
"How do large clusters of fires like California is having affect the weather?"
] | [
false
] | null | [
"Locally, as in directly over and around the fire, it is capable of creating its own weather. It does this by creating immense amounts of heat, pulling air upwards. This leave a low pressure area that wants to be filled. New air fills this lower pressure area creating wind. This process feeds back upon itself, and ... | [
"they don't have an affect at a larger scale",
"Not in California, but wildfires ",
" capable of altering the weather to an even greater degree. When a fire is large enough and the conditions are right, they can create a ",
"pyrocumulonimbus cloud formation",
" in the sky over the flames which in a lot of ... | [
"I've found me to always be the best source of information."
] |
[
"Why do commercial jets have rounded noses?"
] | [
false
] | Fighter jets have a more pointed nose but for some reason commercial jets do not. Why? | [
"Commercial jets fly at subsonic speeds and at those speeds a spherical leading edge (i.e., rounded nose) has the least drag of any shape. At supersonic speeds the shock wave created by the aircraft becomes a bigger factor in drag than the aerodynamic drag. The shock wave will begin at the forward most point of t... | [
"The Concorde is another relevant example for this difference, being a supersonic commercial aircraft (with the associated pointed nose)."
] | [
"The Concorde has a ",
"Droop-Nose",
" that would be lowered for visibility when on the ground and during take-off/landing, once in actual flight it would be raised to the normal position."
] |
[
"Does the stomach have pain receptors?"
] | [
false
] | null | [
"TL;DR: Yes.",
"The presence of afferent nerves (related to sensations being sent towards more central parts of the nervous sytstem like the brain or spinal cord) in the gastrointestinal system (which includes the stomach) has been known for a very long time (e.g., ",
"Bailey & Bremer 1938",
"). This includes... | [
"That makes sense, thank you very much."
] | [
"That makes sense, thank you very much."
] |
[
"Why are the cracks on glass opaque?"
] | [
false
] | [deleted] | [
"Light moving between different mediums (air, water, glass) gets a little bit bent; this is why drinking straws look bent when put into a glass. When the glass pane is smooth, the bend is minimal, since it only transitions twice (in and out). When it breaks, the glass becomes super rough, and air and glass get jumb... | [
"What do you mean by monochrome? If you put a bunch of snow on a red floor, it’ll still look white because very little of the light is making it all the way to the floor and then all the way back. If you shine a red light on it, you will get a red effect.",
"Basically, snow is so good at scattering light that the... | [
"Snow is ice, so yes, each individual snow flake is transparent. But each one bends light in its own accord, so the light that reaches your eye is a mixture of all colors but without defined shape: white, imageless white.",
"The same happens with glass dust, for example. If you fill a jar with molten glass and le... |
[
"Why are antiviral medications so much less prevalent than antibacterial?"
] | [
false
] | It seems like we have a lot of defenses against bacterial infections, and have had them for quite some time. I'm curious why it appears that anti-viral equivalents are so much less pervasive? And the ones we have, seem so much more dangerous than the antibacterial counterparts. | [
"There are fewer unique targets, since viruses mostly use our own cellular machinery. We end up having to target the few enzymes and proteins they have, such as viral proteases or reverse transcriptases. We can also sometimes produce neutralizing antibodies that target viral surface proteins, which opens up some ne... | [
"Yes, this is a great answer. To add one more thing, because viruses need to hijack host cells to divide, most of their active life - the time when their limited set of enzymes are working and are susceptible to drugs - is spent inside host cells. So any treatment also needs to get inside our own cells, and not do ... | [
"So the basic idea with therapeutics used to treat parasites of all sorts is that you want a target that is as unique as possible, because that reduces the odds that it will gum up your own machinery. ",
"When a virus enters a cell, it generally breaks open to reveal its own genetic information, which either dire... |
[
"How does medication (pills, etc.) expire after a certain period? What makes it \"go bad\" or become ineffective?"
] | [
false
] | null | [
"Typically this is due to chemical degradation of the active ingredient (into inactive or possibly harmful forms), or some kind of physico-chemical change to another ingredient (e.g. degradation of the excipients required for controlled release of the active ingredient over time, crystallization or settling of liqu... | [
"It's important to note that these are incredibly slow processes and most medication is perfectly effective past their expiration dates. These are dates that the manufactures can ",
" effectiveness, but ",
"studies have shown the vast majority of common medications have multiple decades of shelf life",
". The... | [
"Yes, I agree that the shelf life dates are incredibly conservative when it comes to the chemical degradation of the drugs themselves. I think the dosage form issue may actually be the bigger one, in many cases; for example, the drug itself may be chemically \"perfect\" but the pill no longer dissolves in the stoma... |
[
"Is there a part of the US that is unlikely to get a natural disaster?"
] | [
false
] | null | [
"ten states with the least number of declared emergencies",
"Mesa, Arizona is the safest overall city. supposedly."
] | [
"Yeah, I can see that. Anywhere dry is going to have less natural disasters and most natural disasters are weather related. And less moisture= less dangerous weather."
] | [
"Tornados."
] |
[
"If our cells constantly replace themselves, how do our bodies or even individual organs get worn out?"
] | [
false
] | Cell replication, as far as my freshman, non-biology-major coursework puts it, is a cell making copies of itself based on instructions passed down through generations. How does the cell, the organ, and the body age if they are constantly being replaced with new copies on the cellular level? As a side question, what or... | [
"Terminally differentiated cells often are unable to proliferate further. Unless there is a stem cell population replenishing them, once they die, they're gone. Additionally, for organs like the brain, if a cell is lost, the neighbors may not be able to compensate for the lost cell's activity.",
"Cells themselves... | [
"I'd vote heart, its the only organ that doesn't change, the cells onky multiply and divide once, an old man has twice the amount of (and the same cells) he was born with in his heart, they don't die off, hince why it doesn't get cancer"
] | [
"Terminally differentiated cells can become cancerous, and primary heart cancers certainly exist. Mostly sarcomas and mesotheliomas. They just are relatively rare."
] |
[
"Does the extra co2 in the atmosphere from factories and cars benefit plant life?"
] | [
false
] | null | [
"The simple answer is no. In lab settings, increasing CO2 concentration has been shown to increase plant growth - but under these conditions plants are not limited by other factors such as water or nitrogen. But it does not work the same way in the natural world - water and nitrogen tend to be the limiting factors ... | [
"back yourself up"
] | [
"Here's an experiment in which scientists raised CO2 concentrations in a natural setting. They laid PVC pipes in areas of forest and pumped CO2 into the open air. They found that poison ivy growth rates increased by 149%, so the effect might depend on the specific plant. (",
"NPR",
")"
] |
[
"Does wood harden if it's underwater?"
] | [
false
] | I've watched a few documentaries and read a few articles about the founding of Venice and one thing that they all mention, is that the Venetians used wooden beams as supports due to the lack of a solid foundation. They would drive these beams into the water and the soft soil until they hit bedrock and, according to the... | [
"Wood rots much slower under water because most fungi can't attack it under water, instead microfungi and and bacteria break it down. Much slower than on land i should add. The broken down area is filled with water. The poles of Venice are mostly European larch who are very resistant to micorfungi and bacteria. But... | [
"Was it known that European larch was more resistant to microfungi and bacteria when it was first being used? Or was the Larch used to replace another type of wood once larch was discovered to be more rot resistant?"
] | [
"I don't have a good source for this but the use of the different woods might indicate that the builders simply took what was availble."
] |
[
"Animal behaviors against each other?"
] | [
false
] | If Animals can't communicate ...most animals anyways, how do they learn social behavior, It's always confused me why an alligator will attack anything that moves , but if it comes across another gator it won't attack it, I'm sure the answer is simple, but I just can't grasp it? Thank you everyone to who commented... | [
"Animals DO communicate, just not through human language. They respond to the sights, sounds and smells of other animals. Even humans and animals communicate. Some animal behavior is instinctual and programmed hormonally or genetically. Other behaviors are learned or some combination of inherited and learned. Dogs ... | [
"Animals absolutely can communicate with each other. Vocalizations, facial expression, body language, and even chemical signals are kinds of communication. Have you ever seen dogs interact with each other? Watch their bodies as they interact. The way they hold their tail, make eye contact, hold their posture, hold ... | [
"To add on the other posts, animals can also recognize individuals. Social animals especially have the ability to distinguish others based possibly a combination of factors including: familiarity, smell, pheromones (MHC complexes), sounds/vocalizations. Thus, they can tell who might be an ally, or an unknown - pote... |
[
"Is it possible that my subconscious is secretly working against me in any way?"
] | [
false
] | Or does it do its bidding with some sort of understanding of what my consciousness wants it to be working on? lol. I know my subconscious is a busy little bugger, I just hope it has no malicious intentions. So far it has only helped me, such as memorizing stuff in my sleep, or giving me dreams that teach me how to r... | [
"Or going any deeper."
] | [
"Or going any deeper."
] | [
"Subconscious is a level of description for cognitive processing, it is not a \"thing\" that can have intensions of its own. Unless you have suspicions of having a particular mental disorder such as Dissociative identity disorder, I would not be worried."
] |
[
"While playing music off my phone in the car, will the rate at which my battery drains differ if I have the volume on max for the phone and low on the car or vice versa?"
] | [
false
] | For example: I plug my phone into the car AUX(non charging) and put the volume on the phone at 100% and the car at level 10 OR I put the Volume on my phone at 50% and the car at level 20(numbers are arbitrary). Is there a difference in the rate at which the battery will drain? | [
"Yes, there is a protocol, it's called Ohm's Law. A speaker is a low resistance and an amplifier front-end is a very high resistance."
] | [
"It will make a very tiny, negligible difference. Increasing the volume on the phone will increase the average output voltage, but since this signal is only going into the high-resistance front-end of your car sound system it will draw very little current and therefore power.",
"FWIW, if I have a stack of volume ... | [
"Higher voltage, but the input of the receiver is super high impedance, so higher voltage won't actually increase the power drain by a whole lot, and it starts out pretty negligible to begin with. "
] |
[
"Why do we measure ppm by volume for gases all the time and not by weight like water and soil?"
] | [
false
] | null | [
"Likely because the molar volume of gases is pretty much the same for everything. So if you take 1 mol ethanol and water, ecaporate it and have the vapor and gas ethanol at the same pressure and temperature they will have the same volume.",
"For liquids and solids its different for each compound and element, usin... | [
"For my work, I sometimes use photo ionization detectors to measure VOC concentrations in the air. The instruments give readings in ppmv. I have always assumed that the use of volume was because it was a relatively easy calculation based on the flow rate of the internal pump in the instrument.",
"The same would w... | [
"Depends on the application. In gas phase analysis, PPM is more useful because you often care about volume and percentage of contaminant more than mass of contaminant. For example, gas chromatography or mass spectrometry.",
"For example, if you're analyzing a pure N2 or argon gas atmosphere for a semiconductor ma... |
[
"Would it be theoretically possible to cast a sculpture out of rock?"
] | [
false
] | null | [
"example A",
"example B",
"example C"
] | [
"Several artists actually ",
" produce artwork through the process of casting natural lava.",
"Their websites should provide the answers you seek as to methods and whatnot."
] | [
"Do you have any examples of this?"
] |
[
"Are there circumstances where scientist and pharmaceutical companies don't have to go through the FDA to release a drug?"
] | [
false
] | (Not sure if the FDA is the organization that handles this type of thing but bare with me here) I'm talking in extreme circumstances. Like the human race is dying alarmingly fast, and if someone doesn't come up with a cure/vaccine soon we're headed for extinction. (i'm being very dramatic here but i'm getting to the po... | [
"The FDA is able to ",
"fast track drugs",
", including reducing testing requirements, under some circumstances.",
"Fast track is a process designed to facilitate the development, and expedite the review of drugs to treat serious conditions and fill an unmet medical need. The purpose is to get important new d... | [
"I'm not sure if exceptions are made in those circumstances. But there are normally human trials as part of the approval process, and doctors/patients are likely to agree to participation in cases like the ones you describe. "
] | [
"Just fyi, \"right to try\" is ethically dubious and not really in the best interest of patients as much as pharma companies. It sounds compassionate, but patients are basically paying money to be human guinea pigs. Below is a well written article about the issue:",
"http://thehill.com/blogs/congress-blog/healthc... |
[
"Is space trash really a problem (today)?"
] | [
false
] | According to United Nations Office for Outer Space Affairs there are almost 5000 satellites orbiting around the earth. It is a lot, but they also have a huge area they can moving through. I imagine travelling in circle around a perfectly smooth earth surface with my super fast vehicle. On the earth there are other 500... | [
"Have anyone seriously calculated the chance of crash? ",
"Yes. It is calculated at design time for every satellite.",
"Unfortunately the question is a bit more complicated. You can't say it has X% probability of crashing because such a statement is missing an important point: the size of the object you receive... | [
"But especially for avoiding creation of more and more debris.",
"That's exactly what debris mitigation guidelines are focused on. A defunct satellite in orbit doesn't pose a lot of collision risk by itself, but if it releases fragments every time it is impacted then it is slowly but constantly contaminating the ... | [
"Thank you so much for the great reply! The report is super interesting.",
"catastrophic event from penetration of 5% every 10 years. (In space context, ",
" means death or severe injury of a human). Those numbers are disturbingly big.",
"They are. I work on railway safety and residual risks of catastrophic e... |
[
"Can you decide if a chemical compound is basic or acidic just by looking at it's structural formula?"
] | [
false
] | null | [
"Formula itself, no. Knowing the structure (i.e., where the bonds are), then yes. This is especially true for organic compounds.",
"We know how a functional group behaves with regards to accepting or donating a proton, so their presence in the compound will give clues to what it will do. However, as with all area... | [
"There's plenty of software that predicts pKa (H+ dissociation constant) from molecular structure based on the principles (electron density distribution) that ",
"/u/rupert1920",
" mentioned. Here's an abstract which mentions some by name and shows a comparison of their predictions:",
"Comparison of Nine Prog... | [
"Use this website:",
"http://www.chemicalize.org",
"It's not very advanced, but its quite easy to use. Just type in something like \"4-methylpiperidine\" or \"morphine\" or draw a structure, and it will give you the pKa's and tell you what the charge will be at any given pH."
] |
[
"If a runny nose, sore throat and sneezing are the body's way of dealing with the common cold, does suppressing the symptoms with medication prolong the infection?"
] | [
false
] | null | [
"Not really. These symptoms are largely a result of the immune system dealing with the common cold, not the sole mechanism by which the body deals with the infection.",
"A sore throat occurs as a result of tissue damage. This is caused by both the virus and the immune response against the virus. You get a runn... | [
"Am I mistaken that rhino-viruses evolved to present the symptoms of excess mucus production, coughing, and sneezing as a way of propagating in new hosts? Or is it a coincidence that we respond to this particular clade of viruses in this way?"
] | [
"It is likely that some pathogens have taken advantage of sneezing and coughing. I personally don't know of any specific pathogens that do this via a distinct mechanism that directly causes coughing/sneezing.",
"I looked into rhinoviruses doing this and found this review: ",
"http://bmjopenrespres.bmj.com/cont... |
[
"How do we know we share a common ancestor with the great apes (chimpanzees, gorillas, orangutans)?"
] | [
false
] | I know we share a majority of our DNA with them. Is that the only evidence we have? (I'll point out I do believe in evolution, and I do believe in this common ancestor theory with the great apes, I'm looking for a more technical "how do we know this") | [
"When you say \"share a majority of DNA\" it may be helpful to expand on that and explain why it is that the DNA we share is such a positive identifier of our mutual ancestry.",
"Lets focus for a moment on ",
"chromosome 2",
". All Hominidae have 24 chromosomes, except for humans. We have only 23 chromosomes;... | [
"DNA is not the only evidence we have, although in my opinion it is the best (it really makes an airtight case against any other possible configuration). Huxley and Darwin, for example, showed by comparative morphology that humans and great apes had a common ancestor well before DNA was ever discovered."
] | [
"One of the two best lines of evidence we have has already been mentioned, the fusion of chromosomes 2A and 2B. The other, my personal favorite (and what I've spent the last few years of my life studying), are endogenous retroviruses and other mobile genetic elements, specifically the way insertions of these elemen... |
[
"is there a speed limit at which current GPS technology becomes useless to ascertain the objects current location with accuracy?"
] | [
false
] | null | [
"Only kind of relevant, but I remember reading on Reddit that if a GPS is going over 1,000 MPH it, by law, must shut off because it is likely guiding a missile. So to narrow down your speed window (assuming the above is true), a GPS is able to track at over 1,000 MPH."
] | [
"It's actually 1000 knots, and there's a limit of 11 miles in altitude as well, but that as far as I know is an export limitation from the United States (receivers that operate past those limits are classified as munitions). ",
"There's nothing inherent in the satellite signal that could prevent a receiver from o... | [
"Before the answer, consider how GPS works: ",
"A satellite in orbit will transmit a signal according to an atomic clock. On the ground in the receiver, another signal is generated. Both signals are generated at the same time, and when the signal from the satellite reaches the receiver the difference is then calc... |
[
"how come people who snore are not woken up by the noise?"
] | [
false
] | null | [
"The short answer is that it actually ",
" wake you up. A close relative of mine suffered from this for many years before having it surgically corrected.",
"From ",
"the American Association of Oral and Maxillofacial Surgeons",
":",
"\"Snoring of this magnitude can cause several problems, including marita... | [
"This is from 1998 but it was the first relevant source that I found via my phone (also explains poor formatting, my apologies):",
"www.jhu.edu/news_info/news/home98/apr98/serena.html",
" ",
"Basically, when we are sleeping, the frontal lobe screens what we are hearing and decides if a sound is worth waking u... | [
"Yes, K-complexes are involved, however more recent research has actually shown that sleep spindles may be more important, as they have been found to be directly related to an individual's ability to maintain sleep in the presence of auditory stimuli. "
] |
[
"Why does water turn yellow when electric current passes through it for some time?"
] | [
false
] | When I was young, I used to play around with electricity quite a bit. One "experiment" I did was to take 12v DC and pass it through a glass of water via two copper conductors. I noticed that, after several hours, the water becomes yellow and cloudy. I'm assuming this is some sort of chemical reaction, but what was happ... | [
"Thanks! This sub is so awesome."
] | [
"Thanks! This sub is so awesome."
] | [
"Incidentally, this is the best way to clean cast iron that has a liner of carbonized gunk on it."
] |
[
"Why does a liquid run down the side of a glass when pouring it?"
] | [
false
] | When I pour a liquid from a mug into another container, it runs down the side of the mug. Why does this happen? | [
"Due to both the high surface energy of the ceramic surface and the lower interfacial energy of the ceramic-water interface. ",
"The lowest energy state is when the water is covering the ceramic and so the water will adhere to the mug as it is poured out."
] | [
"Hot chocolate (made from milk) is not even a single liquid, as ",
"milk",
" itself is already \"fatty droplets\" in water, which is called an ",
"emulsion",
"."
] | [
"The liquid will take the path of least resistance where resistance is the breaking of surface tension. So if you had a superfluid (one with 0 friction) it would fly out the end of the cup instead of wrapping around. If you have a very viscous fluid, say glue, it will hold onto the edge so tight that it will end ... |
[
"Why Do Moths Fly Towards Light Sources?"
] | [
false
] | null | [
"They use the moon as a guide for traveling I believe. So they think the light source is the moon. Of course I could be wrong."
] | [
"No this is pretty much it. Richard Dawkins writes about this briefly in The God Delusion. If I had the book on hand I'd get the quote."
] | [
"That's it. I knew I read it somewhere."
] |
[
"What would happen if we split a proton or electron?"
] | [
false
] | Would it give off energy like when you split an atom? | [
"Electrons are elementary particles as far as we know, so they can't be \"split\".",
"Protons are not elementary, so they can be \"split\", however it requires very high energies. It's done at places like the CERN, with the LHC."
] | [
"Aren't isolated quarks not a thing? The energy required to split a proton would result in multiple hardrons, right?"
] | [
"There's no reason to believe that any miniature black holes are actually being produced in any collider that currently exists."
] |
[
"In perfect conditions, what is the furthest a bullet could possibly fly? For the sake of the question, we'll say standard 5.56x45mm NATO."
] | [
false
] | null | [
"Depends on your definition of perfect conditions. In a total vacuum, for example in space, and absent of external forces like gravity, it could travel forever. ",
"But I'm assuming that's not what you mean, and if it's not, I'm unable to answer further."
] | [
"The equations involving air get a little bit tricky, but without considering air and considering a bullet fired horizontally from the height of a person (1.70m) we can do some math: ",
"Time for the bullet to hit the floor = (height*2/gravity acceleration)",
"Horizontal distance traveled: time*speed of the bul... | [
"I'm saying no wind, no humidity, just gravity and air. Sorry if I'm not being specific"
] |
[
"When you lose weight, where does it go? How does the mass leave the body?"
] | [
false
] | I've been trying to get fit lately, and have lost three pounds. It got me thinking - where does "the weight" go when you lose it? In other words, how does the mass leave your body? I understand that when you lose fat, the fat cells shrink, but the actual mass must escape the body somehow. I can only think of four ways ... | [
"With the help of oxygen, cells eat carbon containing molecules like glucose and fatty acids, and respire CO2 and H2O. The CO2 is in solution in your blood and travels to the lungs, where you exhale it in exchange for more O2. A 140 lb person exhales about 1 kg (2.2lb) of CO2 each day from basal metabolism, more if... | [
"Yes, you can lose a tiny amount of weight just by breathing harder without otherwise exerting yourself, but if you hyperventilate you'll pass out, so that's not really a good weight loss plan. When you exercise, you breathe harder to get rid of all that CO2 that's being dumped into your bloodstream by your muscles... | [
"Yes, you can lose a tiny amount of weight just by breathing harder without otherwise exerting yourself, but if you hyperventilate you'll pass out, so that's not really a good weight loss plan. When you exercise, you breathe harder to get rid of all that CO2 that's being dumped into your bloodstream by your muscles... |
[
"Do adjuvants have any medical use outside of vaccines?"
] | [
false
] | I know about aluminium hydroxide and how it's used to increase the immune response when putting in vaccines. The virus protein interacts with the immune system , leading to an acquired immunity. Aluminium hydroxide increases this effect. But here's the thing. In the case that there's already a virus or pathogen there, ... | [
"They are also used in cancer therapy. Often, but I believe not necessarily, in combination with other immunotherapy, such as cancer vaccines. \nUseful links:\n",
"https://www.cancer.gov/about-cancer/treatment/types/immunotherapy/immune-system-modulators",
"\n",
"https://www.frontiersin.org/articles/10.3389/f... | [
"I’d like to know too. I remember reading about a clinical trial where they had just the adjuvant as a control, and they had a response rate similar to the actual drug. So I’d guess “yes, needs more research” and probably applies to some diseases more than others."
] | [
"I can give you a bit of a more frank, less technical and comprehensive answer that may help. If this helps add to the other answers, great. If not, ignore me. ",
"Adjuvants work locally as well as systemically, but not both in equal measure. They are especially active at the site of the injection. A vital part ... |
[
"If one conjoined twin dies, can the other survive?"
] | [
false
] | null | [
"Unless they can be separated, no, both twins will die."
] | [
"If twin A has an aneurysm, how long does twin B have?"
] | [
"That is something that completely dependent on the type of twins they are, how much blood supply they share, if one is sicker than the other, etc. No real way to guess. Much less than 12 hours."
] |
[
"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! ... | [
"Why are migraines so hard to understand? So many people are afflicted, yet so much is unknown."
] | [
"What is the difference between ADHD and High Functioning Autism?"
] | [
"It comes and goes because the virus infeccts your nerves and then becomes dormant or 'latent' in the sensory root ganglions - the bundles of different nerves that meet together. In the case of genital herpes these are in your lower back, and in oral herpes (cold sores) they are under your cheek bone.",
"Viruses... |
[
"Is it possible to predict the behavior of a substance while only knowing its molecular composition?"
] | [
false
] | [deleted] | [
"You can do it, at least in principle. (Depending on what you're calculating, what you know, what accuracy you want, how much computer time you have, etc)",
"But there's no simple 'rule' for how these things work. It's a whole subject - chemistry. What you can say and predict from simplified rules and generalizat... | [
"Is that true even in principle? I was under the impression that we cannot yet predict \"simple\" properties like melting point with good accuracy."
] | [
"It's definitely true in principle. The alternative would be that there's some fundamentally-unknown force of nature acting at the chemical scale, and we don't believe that. ",
"The problem isn't that the fundamental physics of what's going on isn't known, but applying that physics to a model that's as accurate a... |
[
"If the modern human homo sapien species has existed for hundreds of thousands of years why did civilization only start a little over 10,000 years ago?"
] | [
false
] | null | [
"Generally, farming is considered an integral part of civilization, for a couple reasons. Farming creates large food surpluses that can be stored (grains), which support large settlements of people, and farming requires organization of people to tackle communal projects like irrigation.",
"These things aren't nec... | [
"not that you say so but your question seems to have as a premise that civilization is an inevitability, or that humans will tend to civilise, it may be true but it may not be, civilisation or the tendency to civilise might be rare in the universe even amongst life forms with the capacity to do so. whether it is o... | [
"One theory I've read looks specifically at the period around when agriculture showed up in the near east and notes a significant drying at the time. The idea is that population growth followed by climate getting worse pushes lots of people into confined areas like the Nile valley. Agriculture takes a lot more ef... |
[
"Why Tuberculosis is still a major death cause if we have the vaccine?"
] | [
false
] | I’m not an anti Vaxxer, without any doubt, but i don’t understand, why are there so many deaths every year 1,4M in 2019) because of a disease that has a vaccine since almost 100 Years? Thanks! | [
"The BCG vaccine is not particularly effective, and doesn’t prevent transmission. There is in fact a long-running global effort underway to develop new, more effective vaccines. Some useful background ",
"here",
"."
] | [
"This appeal",
" from the WHO is also worth reading. I know people who have survived TB and multidrug resistant (MDR) TB — it’s a very nasty disease and the treatments are sometimes even worse. A new vaccine is desperately needed."
] | [
"A lot of it is due to limited access to medicine, both treatment and prevention. ",
"87% of all TB cases",
" occur in just 30 countries, all of them unevenly developing nations where big chunks of the populace do not have access to modern medicine due to lack of physically accessible providers, poverty, or bot... |
[
"Is it true that an eyemask pushing against your eyes can interfere with REM sleep?"
] | [
false
] | I've seen these claims thrown around a little, especially in the context of marketing and reviews of contoured eye masks (eye masks that don't push against your eyes); That feature is important because when you go through REM sleep cycles, your eyes often move quite a bit. This mask, with room to open and move your eye... | [
"in my own experience some masks actually reduce my REM.",
"Do you sleep with an EEG each night? If not, there is no way to confirm this statement. This is not a subjective question, it's an objective one. REM is a measurable, quantifiable, brain state. An individual cannot comment on their own REM state, it ... | [
"in my own experience some masks actually reduce my REM.",
"Do you sleep with an EEG each night? If not, there is no way to confirm this statement. This is not a subjective question, it's an objective one. REM is a measurable, quantifiable, brain state. An individual cannot comment on their own REM state, it ... | [
"I don't know that it's ever been studied directly. However, ",
"this study",
" actually shows that eye masks increase REM, obviously by limited light through the eyelids, which can interfere with melatonin production. The only problem is that this study doesn't specify what type of mask was used, but states s... |
[
"Alright, /r/askscience, how possible are these predictions? *link inside"
] | [
false
] | , I find myself highly skeptical to such accounts as "humans will be superhuman". How would we detain our prisoners if they could run rampant? Not just this, but other concepts on this page really make me ponder how possible such a technological explosion is. Scientists of Reddit, what are your thoughts? | [
"Easter Island is a good example of a Malthusian catastrophe."
] | [
"Easter Island is a good example of a Malthusian catastrophe."
] | [
"God I hate that website.",
"fastparticles and dangercollie have hit it on the head with how impossible it is to predict the future, and with that lies most of my anger towards that site, and \"futurists\" (read: spewers of unsubstantiated claims) in general.",
"But allow me to raise another point: that site cl... |
[
"If soil remains dry long enough, do the micro-organisms in it die?"
] | [
false
] | null | [
"That's actually an incredibly interesting question. I don't see why not, it would be pretty amazing, if worrying!",
"\nFor the latter question, I don't see that simply drying out the soil would reduce the nutrients, in much the same way that boiling water leaves the salt, although I could easily be wrong."
] | [
"In some cases, the microbes may die, but many have adapted to conditions, often by mechanisms such as ",
"spore-formation",
".",
"\nIn spore formation, the organism enters a state of reduced metabolism (amongst other biological changes), which allows it to survive difficult conditions.",
"\nA prominent exa... | [
"Just wanted to add to your great explanation with this: Under my knowledge, the only condition that endospores form in is a condition of starvation. So simply being arid isn't enough-- they have to have a lack of nutrients. "
] |
[
"I'm an average male. If I drink an alcoholic drink over the course of 10 minutes, at what time will I be the most inebriated?"
] | [
false
] | So say t=0m I start drinking, t=10m I finish, at what t(m) will the most alcohol be in my system? For more specificity, let's say I'm 160lb, 5'10'' tall, and it's 16oz of a 5%(alc./vol.) beer. | [
"The not-so-helpful answer: anywhere in a big range of times. Both absorption and elimination rates vary a ton person-to-person, which makes most alcohol-consumption-related rules of thumb unreliable.",
"A frequently cited, but somewhat old, study is ",
"this one",
" (1985), which I can't seem to get a copy o... | [
"You forgot to convert to metric %ABV..."
] | [
"And metric minutes."
] |
[
"How do ships sail against the wind?"
] | [
false
] | [deleted] | [
"I think I can answer this one. I have tried tacking on a square rigged boat, and I have a fairly good understanding of sailing theory. I will answer in two parts. First I will talk about why a square sail is not very good for sailing a close-haul, secondly I will talk about why tacking is difficult on a square rig... | [
"Ships do overall go against the wind, but not straight forward. This is possible because of triangular sails (square ones make it much more complicated.) They go against the wind with a slight angle. Keel under the boat prevents it from going sideways, so boat can only move either forwards or backwards. As long as... | [
"By ",
"Tacking"
] |
[
"Climate change books/papers/survey papers?"
] | [
false
] | Hi everyone, A issue I feel strongly about politically is climate change. Everything I've read points toward the evidence being statistically overwhelming. However being a good scientific sceptic I'd rather not rely on third party sources and would be keen to read the important papers myself. Does anyone have any refer... | [
"I get to link to my favorite video (yay): ",
"http://www.agu.org/meetings/fm09/lectures/lecture_videos/A23A.shtml",
"This talk was given by Richard Alley at AGU a few years ago. He mentions the names of researchers to google and the years of their paper."
] | [
"OP, here's the ",
"2007 synthesis report",
" and ",
"all the rest",
"."
] | [
"Start with the IPCC reports."
] |
[
"Do supergiant stars generate more energy in their death than they do in their life?"
] | [
false
] | I'm really interested in stars for no particular reason. Earlier today, I had heard a physicist say making a stable wormhole would require amounts of energy equivalent to creating a black hole out of a star—a supernova. Idk if they're right, and the validity of the statement isn't the focus, really. I'm more curious ab... | [
"A star of 8 solar masses might have an output of 4e29 Watts and a lifetime of 80 million years, that translates to an estimated total output of 1.0e45 Joules from fusion energy. I did a quick estimate of the fusion energy released in the last phase of life of such a star as roughly 1.44 solar masses of Silicon et ... | [
"In a very, very broad sense, the scales here are similar. A typical supernova is about on par with the lifetime energy output of the Sun. Stars have a variety of lifetimes and luminosities, so there's quite a range of possibilities.",
"But I think you can safely say that they're on par."
] | [
"Yup. Fusion reaction rates are very non-linear with respect to temperature and pressure. Inside the core of a massive star not only is the pressure and temperature in the exact center higher but the entire volume that is at fusion supporting conditions is also larger, leading to overall much higher rates of fusion... |
[
"Do rainbows have ultraviolet and infrared bands?"
] | [
false
] | null | [
"In fact this is how infrared light was first discovered. ",
"Herschel directed sunlight through a glass prism to create a spectrum - the \"rainbow\" created when light is divided into its colors - and measured the temperature of each color. He used three thermometers with blackened bulbs (to better absorb the he... | [
"This is one of the coolest experiments I've ever heard of."
] | [
"indeed, good answer - and only a couple of weeks ago I stumbled on ",
"this pretty cool photo",
" which clearly shows where the UV and IR bands sit. ",
"Because of the way the image is filtered, you don't see \" colored bands\" like we can distinguish in the visible region, but if you used, for example, a se... |
[
"Electromagnet in space: how do the force/attraction work over time?"
] | [
false
] | This is based on a thought experiment proposed in a podcast: What happens next? Presumably the two will move towards each other at some point, the force shouldn't act before the information can arrive (i.e. 1 hour). How does it work? I understand this doesn't have to be huge or in space but it makes the concepts easier... | [
"Going by Mazwell's equations, electromagnetic fields are disturbances in points in space that influences other nearby points which further influence other further points, and so on.",
"The moment the electromagnet is turned on, the the disturbance is created near the face of the electromagnet, which creates a fi... | [
"Where are you getting 10 hours? Was there an edit or maybe you read the post wrong? I also think you are missing the idea of the thought experiment, what happens to the electromagnet, does it just seem to accelerate after it is turned off?"
] | [
"I read the post wrong I think. "
] |
[
"Are there any advancements in aircraft that don't use jet or rocket fuel?"
] | [
false
] | Say tomorrow we use up our last drop of rocket fuel and jet fuel and whatever fuel propeller planes use; would all aircraft seize to exist? (besides blimps and hot air balloons and stuff like that) | [
"We would just make more. Jet fuel isn't that different from gasoline. The only real difference is the length of the hydrocarbons. We could get more jet fuel by just refining it from crude oil, or cracking very long chain hydrocarbons into the kind in jet fuel. If we really got desperate, we could it theory pro... | [
"You already have (unmanned) solar powered electric planes.",
"You can also make nuclear airplanes. I don't know if you can go supersonic without jet fuel (today) but you certainly can fly - propellers attached to electric motors."
] | [
"http://www.npr.org/2011/09/26/140702387/air-force-and-navy-turn-to-bio-fuels",
" ",
"This is just the beginning, I believe that Honda is working on a hydrogen powered jet as well."
] |
[
"Why do antidepressants vary so much in effects, efficacy and side-effects from person to person?"
] | [
false
] | First off, this is absolutely NOT an attack on antidepressants or anyone who uses them - they're clearly extremely helpful for a huge amount of people, and I'm currently weighing up the pros and cons of starting them myself. What puts me off, though (and kind of confuses me) is the huge variation in stories you hear fr... | [
"I think some of it has to do with the dosages given. For example, when I was put on 20mg of Prozac from nothing, it put me through absolute hell and hospitalized me twice. After that, I was put on a pediatric dose of Lexapro and allowed to gradually increase my dose by 5mg increments every other month or so. A yea... | [
"See ",
"this thread",
" asking the same question from a few years ago.",
" ",
"Basically, SSRI is a class of many different drugs (Prozac is fluoxetine and Lexapro is escitalopram, for example) each with a different structure. This structure can affect how the drug affects you. ",
"Also, is there any ot... | [
"Part of it is that these patients may not all have the \"same illness,\" as depression has many causes and manifestations.Some may be pure serotonin deficiency, some may be environmental, some may be caused by a completely different neurotransmitter, and some may be misdiognosed. And because serotonin also regulat... |
[
"Why can we store carbohydrates and fat as unnecessary adipose tissues, but not store protein, which actually helps us to grow and repair?"
] | [
false
] | Surely meat has been in our diet long enough for us to evolve to store protein in our bodies. We can't use most of the adipose tissue our body stores (especially true in larger people) but we cannot store protein? Just revising for an exam, and the question popped into m head. | [
"Fat stores energy more efficiently than protein (i.e. you can get more ATP from oxidizing fat per gram than you can from metabolizing protein). This is partly because fats can be stored extremely efficiently because they are hydrophobic, so a huge associated store of water is not required. The amount of water that... | [
"additionally, a skeletal muscle can lose about 50% protein content on average before significantly weakening in strength. They do function as a sort of functional protein storage in that regard; the protein contents of skeletal muscle are capable of compensating lack of protein or glucose nutrition (via gluconeoge... | [
"Energy aside, what about just storing them for their use as building blocks for any future repairs and growth and such. Wouldn't that be pretty darn useful."
] |
[
"Is it possible that we are in a tiny corner of the universe?"
] | [
false
] | [deleted] | [
"Space expands faster than light.",
"Actually, the expansion rate depends on the length scale. The farther apart two bodies are, the faster they're moving apart. Stuff ",
"more than about 16 billion light years from us",
" right now would be away from us at faster than the speed of light, assuming it's there.... | [
"All points are the centre. Every point in space is moving away from every other point in space, the further away it is the faster it is moving away from a relative perspective.",
" Think of it like this... Point A is where the bit of the universe that contains Ap0llo exists at the start of the big bang.",
"Poi... | [
"All points are the centre. Every point in space is moving away from every other point in space, the further away it is the faster it is moving away from a relative perspective.",
" Think of it like this... Point A is where the bit of the universe that contains Ap0llo exists at the start of the big bang.",
"Poi... |
[
"Why does shaking a carbonated beverage cause it to violently erupt after opening it?"
] | [
false
] | null | [
"This is more of a physics question.",
"The beverage is a solution of carbon dioxide, various flavorings, and some kind of sweetener. The beverage is pressurized, which is important because the solubility of gases increases with increasing pressure. This means that the beverage has more gas dissolved in it in the... | [
"Before the carbonated beverage is opened, there is a layer of high pressure CO2 sitting on top of a layer of water containing dissolved CO2 (and sugar, flavours etc). When you shake it up, instead of the two layers being neatly stacked on top of one another, bubbles of CO2 will be dispersed through the liquid. You... | [
"The explanation there is much shorter. You're allowing the gases to dissolve back into the liquid. The extra pressure from squeezing it increases the solubility of the gases, as well as allowing time for the process to occur."
] |
[
"How do we know how old viruses are?"
] | [
false
] | I've seen it multiple times that viruses have existed on earth for billions of years, but also that they don't appear in fossils. How do we know viruses are 3-4 billion years old? I've tried googling it but the answer seems hard to find | [
"first of all they're the most simple (and yet the most effective) life form, and therefore it's only logical they can represent one of the first steps in the evolution grand scheme (some scientists believe they evolved from a different branch of cells that sort of regressed tho): specifically the RNA ones are the ... | [
"One method:",
"(1) We can measure genetic drift rate of DNA.",
"(2) We can find partial or whole retro viruses encoded in DNA of animals such as humans because they insert themselves during replication.",
"(3) We can compare the viruses of today to the encoding of the virus in the DNA, and we know the age of... | [
"English is my first language and you’ve explained it better than I could"
] |
[
"What is the actual research behind the benefits and possible negative effects of organic farming, and consuming those products over non-organic stuff?"
] | [
false
] | I've been hearing very convincing arguments from both sides about this recently. What exactly does the science have to say? Are people who eat a healthy diet with tons of fruits and veggies healthier if it's organic, or does it not really matter? Does it have a lower environmental impact? Are there any flaws in how the... | [
"Studies have shown that nutrients in organic vs conventional farming are equal, or in favor of conventional farming, taste tests(which are subjective) also show a favor of conventional farming. Blind taste tests consist of not knowing which fruit/vegtable is organic; being told the organic is conventional and conv... | [
"This is great. Thank you for all the information. Seems that unless you have the disposable income to shell out more for your veggies, it's not really worth it. "
] | [
"I can't comment on \"big organic\" or \"big conventional\" as I don't buy it.",
"For me I find that goods produced by a home garden and the ",
" organic farms taste better as you can use different varieties, and being small can afford to keep the smaller, less efficient but better tasting ones around. There's ... |
[
"How does a rifled barrel improve accuracy and projectile stability? Moreover, how does spinning something (a top, for example) keep it stable?"
] | [
false
] | I understand that firearm accuracy increased massively when rifling was introduced. How does spinning a projectile stabilize it and keep it on course? What are the centrifugal/centripedal forces at work here? Is there an optimal speed to spin a projectile at for it to fly straight? | [
"More specifically, spinning the bullet gives it high rotational momentum, making it difficult to rotate perpendicular to its current rotational axis, which means more difficult to pitch or yaw (that is, tumble)."
] | [
"More specifically, spinning the bullet gives it high rotational momentum, making it difficult to rotate perpendicular to its current rotational axis, which means more difficult to pitch or yaw (that is, tumble)."
] | [
"Thank you very much. That was an excellent answer and this is an excellent subreddit."
] |
[
"Would a person experience the G forces of acceleration and turning at high speeds in space?"
] | [
false
] | null | [
"Yes, because these forces are unrelated to gravity, they are due to a change in your motion. F=ma and all that. We only call them \"G forces\" (eg. multiples of the standard earth gravity) to give humans a frame of reference for the total force. If I say the acceleration was 2G, you understand that it makes you fe... | [
"Exactly. Anything with mass has inertia, which resists changes to motion. If your body is moving in a straight line at a constant speed, and then something causes you to slow down or change direction, your inertia wants to keep you doing that same speed in a straight line. The force you feel is the force required ... | [
"What I don't understand is what would be pulling on us if it isn't gravity. Is it just the force of our acceleration we are feeling? Also, thanks for answering!"
] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.