title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"What condition does this newborn baby have?"
] | [
false
] | null | [
"We have strict guidelines against medical advice which include offering diagnoses. We also cannot speculate based on anecdotal evidence / a single picture."
] | [
"What are you talking about? I'm just curious what condition this COULD be..."
] | [
"We try to avoid all posts that require speculation here."
] |
[
"What's the point of recycling biodegradable food waste? If it goes to landfill won't it turn into compost anyway?"
] | [
false
] | Seems like a waste of energy to recycle food waste separately. If it goes to landfill am I wrong to think it might even aid the degradation of other less perishable waste like paper and packaging etc. Why, in the UK, is this prioritised over processing batteries separately? Example Camden Council, London: | [
"The point of composting is to recover usable biomaterials at the end of the process. Putting it in a traditional dump means it won't be of any use to anyone unless you want to sift through gigantic piles of garbage at a huge expense to collect some in a few years."
] | [
"Removing and composting biomass to re-use it reduces landfill. Most plastic garbage does not appreciably decompose in a reasonable time - most of it will stay as useless landfill for the foreseeable future. Or until we develop bacteria that can decompose plastics."
] | [
"Are useable biomaterials at a premium these days? Don't they just use animal waste? I just wonder whether it's worth it really? Separating the waste food plus all the other processing and transportation costs."
] |
[
"Before genes are sequenced, how do scientist make sure they are using the genes from the right organism?"
] | [
false
] | As a birthday present I am getting my genes sequenced by a private company. For my sample they send a tube that I have to fill with spit then seal, shake and send back. Once they get my sample how do they make sure that its actually my genes that are sequenced and not some bacteria or other organisms (cow cells from a recent rare steak or something)? | [
"The tests use human specific primers/probes for DNA amplification and sequencing, and the sample tube has chemicals that retard bacterial growth. Most of the interference from bacteria is a degradation of human DNA in the sample, it's not really possible to sequence the bacterial genome instead of yours."
] | [
"As a birthday present I am getting my genes sequenced by a private company.",
"If it cost less than $10,000 then you're probably not. You might be getting genotyped by a SNP array, e.g. 23andMe is one company that does this. The difference is that they just test a fixed set of several million common SNPs (single... | [
"hmm, i'm not sure if there's something that they specifically do but from my own experience in the lab getting my samples sequenced I can tell you the following: the tube they send you is alread sterile and you're going to fill it with your spit so your DNA will probably vastly outnumber the DNA of any errant cell... |
[
"What is happening when I push through sleepiness? (x/post from r/answers)"
] | [
false
] | Asked this in and was told to bring this here: Just wondering what is happening biologically when I push through a bout of sleepiness. For instance, I take night classes and by about 8pm I'm hit with the drooping eyes and fogginess. But I power through and in about 15 minutes I feel extremely refreshed as if I had actually slept a little bit. What is happening here? How can I feel as if I've gotten any rest at all while through the duration of this mental v. physical battle I am in an extreme haze? Always wondered this. Thanks in advance for any insight! | [
"This question is really too personal to answer well. There are many many factors that can result in a temporary reduction in sleepiness. Light has a direct alerting effect. Timing of meals and/or caffeine intake will also affect your sleepiness profile.",
"If we consider the case where all other factors are oste... | [
"How do parts of the brain become \"fatigued?\" Are chemicals used up, or cells or organelles worn out, or what?",
"This is still an open question -- likely, all of the factors you mention are involved to some degree. We know that ",
"ATP levels in the brain decline during wakefulness and surge during sleep",
... | [
"How do parts of the brain become \"fatigued?\" Are chemicals used up, or cells or organelles worn out, or what? ",
"I've also heard it suggested that REM sleep in particular is involved in sort of re-calibrating muscles, and ingraining \"muscle memory.\" Would you agree with this, and if so how does this relate ... |
[
"What's wrong with this argument against evolution?"
] | [
false
] | : The critical factor in evolutionary change is not actually time. Instead, it’s population size and generational turnover. This is because the requirement is that substantial variability be provided (by population size) and many opportunities for selection to whittle down a generation and act on that variation. This is very important, because it means that what Darwinists claim we can’t see, we actually can see. We can examine what occurs, given a certain amount of evolutionary resources. Malaria has existed on this planet for several millennia, and operates by invading hemoglobin, eating it from the inside out, and destroying it. Its structure is such that it can only survive in very warm climates, however. Given the enormous population of malaria across the planet and the rapid generational turnover- each infected person has billions of malarial organisms that multiply exponentially- malaria Think about that. This is what is supposed to have created the human brain? I suspect there are some fallacies here, or misconceptions about evolution. How would you respond to this person? | [
"It's pretty clear that this person doesn't know what they're talking about. \"Malaria\" is a disease, medical conditions can't evolve. The pathogen that causes malaria, and that is capable of evolution is (primarily) Plasmodium falciparum (Plasmodium). Plasmodium doesn't invade hemoglobin, which is a molecule, and... | [
"This is stupid beyond belief.",
"Do you know why there's no malaria in the USA? Because the (precursor of the) CDC ",
"eradicated it in the 1950s",
". That's within living memory. ",
"Malaria used to be a major killer in places like Michigan and Illinois. ",
"Here",
" is a map showing malaria deaths in... | [
"Good answers here but Im just going to correct some other misconceptions. ",
"When it comes down to it, their argument seems to be that because microorganisms can evolve faster (which to be fair is the kernal of truth here) that they should have plenty of time to evolve to be everywhere. Do you see the problem h... |
[
"If pure energy is a by product of anti matter and matter meeting could we theoretically reverse the process and take pure energy and make it into anti matter and matter?"
] | [
false
] | [deleted] | [
"There's not such thing as pure energy. It's just not a concept.",
"Matter and anti-matter typically produce high energy photons when they meet. The reverse can happen, for example a gamma ray can interact with a nucleus and produce an electron-positron pair."
] | [
"Yes, it's called pair production. Check out the beginning of this article:",
"http://astrobites.org/2011/05/21/when-photons-talk-to-each-other/"
] | [
"Pure energy is not a good phrase, since energy always takes some form. For example, when matter meets antimater, they usually annihilate into photons, which are particles of light. The energy in this case is given by the frequency of the light, or how fast the light wave is oscillating. The higher the frequency, t... |
[
"Are man made or artificially triggered earthquakes possible?"
] | [
false
] | [deleted] | [
"Here",
" is an article on NBC discussing a possible link between sixteen earthquakes in Texas in November and fracking. Fracking, or ",
"hydraulic fracturing",
", is the injection of water in to a wellbore with the intent of creating fractures in rock to extract something, frequently natural gas.",
"And ",... | [
"In theory there are ways to induce earthquakes, changing the stress state or changing pore pressures (which can influence the stress) in an area of the crust near faults or fractures can cause small earthquakes. Earthquakes related to these are almost always byproducts of human activities, e.g., filling reservoirs... | [
"Well we use earthquake monitoring systems to detect underground atomic detonations. Just like those that occurred when North Korea tested their bomb. So technically that is an earthquake that it is detecting. ",
"It is not beyond the realm of possibilities that a well place nuclear explosive could help a major f... |
[
"Waking up in the morning: Why is it that when I sleep outdoors I'm able to wake up bright and early feeling refreshed?"
] | [
false
] | Furthermore, why is it that when I sleep for a full 9 hours I still feel crappy when the alarm rings? I know it has to deal with your sleep cycles, but how are these sleep cycles influenced by external factors (light, sound, temperature)? Edit: Thanks for all of the great information! I suffer from sleep phase disruption, which essentially means my circadian rhythm has gone off the deep end. But whenever I sleep outdoors, I find that I fall asleep easily at nightfall and wake up refreshed in the morning. I was just wondering if there was any way to bring whatever factors exist outside into my bedroom. | [
"You know, that is very interesting. I'm sure I know the answer:",
"So the pineal gland in your brain is very involved in your circadian rhythm (biological clock), and it produces and secretes melatonin which is a chemical that basically makes you sleepy due to a pathway I won't explain. Anyway you can buy it in ... | [
"You can buy alarm clocks which try and emulate this by having a light that gradually gets brighter until the alarm clock goes off. But how well they work is up for debate.",
"http://www.amazon.co.uk/Philips-HF3485-Wake-up-Light-Playback/dp/B0044YO9BE/ref=dp_ob_title_hpc",
"Is an example of one."
] | [
"Sleep with the curtains open."
] |
[
"Given sufficient computing power, how accurately could we theoretically predict how an organism would look and act based solely on a genome?"
] | [
false
] | null | [
"You're asking if we can predict the phenotype of an organism just from its genome. There are basically 2 ways to go about this. A ",
", from first principles simulation of the genome and its products OR by homology where we would match the genome (information) content to other genomes we know.",
"The homology... | [
"This is a very clear and understandable answer, thanks for the detailed response. "
] | [
"Just to add to this, there is a distributed computing project that uses hundreds of CPU years of computation just to see how a specific protein folds. We are no where near the level of cpu power it would take to create a true simulation that reflects reality."
] |
[
"Why can't we pair a bluetooth device with two others simultaneously ?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"guidelines.",
"You can find the basic answer with a google / wiki search. Please start there and come back with a more specific question.",
"If you disagree with this decision, please send a ",
"m... | [
"How on earth is my question hypothetical ????"
] | [
"You're asking about capabilities Bluetooth does not have, thus a hypothetical function & design."
] |
[
"Why is the force of gravity taught as a constant, e.g. -9.8 m/s², when Newton's law depends on the distance?"
] | [
false
] | For that matter, wouldn't any inverse-square law force depend on the radius? | [
"The -9.8 m/s",
" refers to the acceleration due to gravity near the surface of the Earth, not the acceleration due to gravity in general.",
"In fact this arises from the inverse square law and the fact that the Earth is so much larger than the distances we typically move. The acceleration 9.8 m/s",
" is the... | [
"Calculate the difference in potential at the two points and set that equal to the kinetic energy of the object."
] | [
"Exactly what my teacher told me a year ago and what we use for solving sums at the high school level. Although the value of g depends on the latitude, the largest difference on the surface on the earth is only 0.05 m/s",
" between the equator and the poles which isn't considered significant enough unless absolut... |
[
"If pushed, would a frictionless marble roll across a surface or glide?"
] | [
false
] | null | [
"If it was pushed in-line with its center of mass it would glide, and if it was given some torque as it was pushed it would have a rolling component, but it wouldn't roll without slipping, which is what most people mean when they think of rolling."
] | [
"To create force you need a force at a distance. In a frictionless sphere, all force is neccessarily applied normal to the surface, this pointing toward the geometric center of the sphere. To get rotation, you simply need a sphere which has a center of mass that doesn't align to the geometric center. To do that, yo... | [
"Frictionless bodies in a continuous fluid are well described by potential flow. In potential flow, there is no force tangential to the flow (i.e., drag), and, in fact, friction must be accounted for to have a force normal to the flow (i.e., lift). That leads to one of my favorite facts about the world: minimizing ... |
[
"Why don't soft drink companies use Oxygen as their fizzing gas?"
] | [
false
] | I understand that it would introduce a higher risk of fire, and the possibility of law suits about oxygen poisoning, but it seems as if a drink that made you feel alive and energised would sell very well despite this. | [
"Actually at 25oC and 1 atmosphere pressure:",
"Solubility( ",
" 2) = 8.27 mg/l",
"Solubility( ",
" 2) = 1450 mg/l",
"So Carbon Dioxide is ~175 times more soluble than Oxygen at SLC (Standard Laboratory Conditions)"
] | [
"Who says it would make you feel alive and energized? The body doesn't take in oxygen from the digestive system. The risks associated with the cost, storage, and transportation of oxygen in relation to co2 definitely outweighs any benefit that ingesting oxygenated water might have.",
"Also, CO2 is practical becau... | [
"Well of cause there are a lot of drinks where the CO2 isn't added but produced as a side product in the production it self (e.g. beer, cider...)\nBut I guess you are going for Coke and other softdrinks, so:",
"I couldn't find a graph showing what my thought was, but I could imagine that the difference in solubil... |
[
"[Sponsored Content] - How does Quantum Healing regulate our Aura and remove toxins?"
] | [
false
] | I know my body is entangled between states of sickness and health, but how do I perturb the Hamiltonian such that I'm more likely to be measured in the healthy state? | [
"You should buy this ",
"hexagonal water",
". It heals the Devil away and brings Jesus into your soul."
] | [
"The basis of Quantum Healing is only recently understood by Western Scientists, while the ancient Chinese understood it for thousands of years. Our Western Scientists have called this the ",
"Delayed Choice Quantum Eraser",
". ",
"We begin by entangling neutrinos and accelerating them faster than the speed o... | [
"Aura's aren't real science. Why is this in ",
"r/askscience",
"?",
"The only thing that's proven to heal your body is ",
"aligning your chakras",
" with chiropathy."
] |
[
"How does the theory of relativity make sense at all?"
] | [
false
] | null | [
"See:",
"https://en.wikipedia.org/wiki/Time_dilation"
] | [
"\"Continuous\" just means that it doesn't have quantized, discrete units. Time being continuous doesn't mean that it can't be relative depending on observer.",
"I recommend you to read one of the many introductory sites about time dilation. Something like ",
"this",
", for example. Or, conversely, what don't... | [
"\"Continuous\" just means that it doesn't have quantized, discrete units. Time being continuous doesn't mean that it can't be relative depending on observer.",
"I recommend you to read one of the many introductory sites about time dilation. Something like ",
"this",
", for example. Or, conversely, what don't... |
[
"Do sound waves from instruments travel the same in zero G?"
] | [
false
] | null | [
"Sound waves are not significantly affected by gravity."
] | [
"If you mean that you couldn't hear him playing his guitar, it has nothing to do with being in space, just that they haven't recorded it, or haven't put it into the edit.",
"There is no reason why sound would not travel without gravity. Sound is pressure waves in air (or any matter). So as long as you have air be... | [
"You say you \"will be able to hear ",
", no matter what the source is.\" Will this sound be distorted or sound clearer/muggy?"
] |
[
"Would a boat float on top of a large ball pit? What are the major factors impacting the question?"
] | [
false
] | null | [
"It's not about the relative size of the the objects (quantization). The problem is that the balls have a very low kinetic energy compared to their inter-ball friction. It wouldn't matter if you had an enormous thing the density of air covered in balls, it still would not rise because the apparent viscocity of the ... | [
"Not in the sense you're thinking. Objects float in liquids because the upward pressure exerted on the submerged portion is greater than the downward pressure + force of gravity. It works out that the amount of fluid displaced must have greater mass than the object in question.",
"This alone would be achieved by ... | [
"You have to make it really lightweight to have a density lower than the ballpit. You can put it on top and then not move anything around, that will work (unlike with an actual liquid)."
] |
[
"How large if a role does genetics really play in obesity?"
] | [
false
] | null | [
"One way scientists can figure out how much effect genetics vs. environment has an affect on a trait is to compare that trait between identical twins (individuals with identical genomes) who were raised in the same household, and identical twins who were raised in separate households. ",
"Scientists in this ",
... | [
"Although it will be different for each individual, genetics do play a role in obesity to an extent, but calorie intake and exercise will still play a huge role in obesity. The paper below gives an example of how genetics can influence obesity. A certain allele of the FTO gene is implicated in obesity by disrupting... | [
"I'm actually studying to be a personal trainer and here's a quote from my textbook:",
"\"Even though heredity influences physical fitness and health, everyone can lead a healthy or unhealthy life regardless of genetic makeup. It's not possible to establish the relative portion of an individual's health or fitnes... |
[
"Is it possible for pi to take on different values when moving at a relativistic velocity?"
] | [
false
] | In my class on special relativity we never considered rotating objects and it got me thinking. If a disk is rotating at a relativistic velocity, then the outer edge with be Lorentz contracted relative to the centre meaning the circumference of the disk will be less than 2piR. However the disk won't be contracted in the radial direction, which would mean that pi is less than 3.14. I don't see any error in this. Does this make sense? If I'm right, can this happen to other transcendental numbers like e? What would a circle even look like in a rotating reference frame? | [
"Pi is defined as the ratio of circumference to diameter of circles in a specific geometry (namely, the Euclidean one). It's not relevant to pi what shenanigans circles may get up to in other geometries. Your circle has a different ratio, possibly, but the connection to pi is flawed.",
"An idealized human has two... | [
"The circumference of a circle rotating with constant angular velocity as measured by a co rotating observer is",
"C' = C/γ",
"Where C is the circumference measured at rest. Straightforward application of Lorentz contraction.",
"The issue is, as you pointed out, the radial direction has no contraction. The re... | [
"C/2γR = pi",
"C is the rest circumference, R is the radius, γ is the Lorentz factor for the tangential velocity component v. More compactly, of course,",
"pi/γ = pi",
"Edit: math."
] |
[
"How do scientists know that ancient hominid fossils are a different species and not just a strange unique example of one individual early man?"
] | [
false
] | I am mostly asking about hominid and "early man". I see a ton of diversity these days. How can scientists know that the body types they find, the size of hands, brow, forehead, etc... How can they say "oh that's a different species" and not just "oh this one had strange tall shoulders", you know? I'm talking like a million years ago where the genius homo popped up. | [
"It really comes down to process of elimination. Forensic Anthropology Is the study of human skeletal remains. By having a skull/skeleton you can tell a lot of different characteristics in modern humans. Such as ethnicity, gender, age, and even how they died in some cases. The skull is usually the most prominent gi... | [
"For one thing, we've got hundreds of specimens of varying levels of completeness at this point. For another, the differences in bone structure are much greater than the variation we see within humans today. You don't see many people walking around with brains a third the size of everyone else and jaws protruding a... | [
"We have DNA from Denisovans and that’s the only way we were able to determine that they are a different species, for example.",
"Also your link discusses DNA from African humans. It’s much more challenging to get DNA from Africa than other parts of the world since it’s warmer and there are no glaciers."
] |
[
"I've found what looks to be a glow in the dark microbe in my laundry room. Google hasn't given me any leads."
] | [
false
] | [deleted] | [
"When you say: \"The place in question has not seen water in months\", do you mean it is as dry as could be or could there be growing a mold.",
"A group of tropical slime molds is known to be bio-luminescent [1]. But without pictures it is very difficult to do anything more than speculate. I am also not to sure a... | [
"Can you link a picture?"
] | [
"Laundry detergent contains ",
"Optical Brightener",
" agents that phosphor to make clothes look whiter. But they seem to cause more of a bluish glow than a golden glow."
] |
[
"Can scientist predict volcanic activity and why hasn't anything like Pompeii happened recently and how long after an eruption does a place recover?"
] | [
false
] | [deleted] | [
"Can scientists predict a volcano eruption, and if so how soon can they do it and how?",
"To some degree yes. It isn't perfect, but scientists can monitor pressure changes and earthquakes to tell when a volcanic eruption is imminent. Of course, sometimes they miss something and sometimes they predict an eruptio... | [
"The ",
"Montserrat eruptions",
" starting in 1995 were pretty destructive, but only killed 19 people because they were able to evacuate the island."
] | [
"1) They can forecast eruptions, not predict them. They can say that an eruption is likely within a certain span of time. For example, the Cascades Volcano Observatory might say that it's a fair bet that in the next 100 years, one of the Cascades in the western United States will erupt. In early May 1980 they were ... |
[
"What does askscience say about the argument presented in this article? Deconstructing Nuclear Experts"
] | [
false
] | null | [
"What arguments? It's mostly just a load of mud-slinging. Psychologists aren't scientists. \"Physicists are stupid\" - I mean, seriously. As for the the few-and-far-between things resembling actual relevant information, I'll just comment on that cancer study from \"Lynkoping [sic] University\", about cancer rates i... | [
"There are claims that reactor 3 at Fukishima is cracked, that plutonium has been found in the soil, the the spent fuel tanks are exposed to the air and burning, and then there are counter-claims. ",
"Are any of those points in doubt? I think everyone agrees those things have happened, people only differ on thei... | [
"The article uses rhetoric that's not credible; however, some of your rhetoric is also suspect:",
"If so then why is no one freaking out about coal power plants",
"This is irrelevant, just a rhetorical diversion. It's like saying, \"why are you upset about this nasty car wreck, when there are other nasty car wr... |
[
"I learned in University, that photons are released by electrons that are decreasing in energy. So how do neutron stars emit light?"
] | [
false
] | null | [
"Atomic transitions are not the only way that light can be produced. Any particles which interact with the electromagnetic force can emit photons, in various different physical processes."
] | [
"So specifically for neutron stars, I would assume that the neutrons interacting with the magnetic field of the star causes photons to be emitted? If you wouldn't mind explaining what this process is that'd be helpful."
] | [
"Neutrons have magnetic dipole moments, so they can undergo electromagnetic interactions that release photons. An example would be a neutron flipping its spin direction in an external magnetic field, and emitting a photon."
] |
[
"If light wasn't dispersed or warped by anything, would our night sky be pure white from the light of every star showing full strength?"
] | [
false
] | [deleted] | [
"Depending on what you have in mind, these previous discussions might be relevant:",
"http://www.reddit.com/r/askscience/comments/lweu4/why_isnt_the_universe_bright_everywhere_all_the/",
"http://www.reddit.com/r/askscience/comments/elfbc/olbers_paradox_a_thinking_excercise/",
"http://www.reddit.com/r/askscien... | [
"But light ",
" dispersed by something - the inverse square law of propagation. You can't assume that doesn't happen without breaking all sorts of laws of physics/mathematics, at which point the answer you get is meaningless.",
"If light wasn't dispersed, magically, then each star would shine light on you no di... | [
"Cool, I guessed right! No prob :)"
] |
[
"Are there any \"rock-paper-scissors\"-genes?"
] | [
false
] | I'm in my last year of high school, and learning about genetics. So far, we've covered dominant and recessive genes, as well as codominance and such. Are there any genes where the alleles dominate each other like in a game of rock-paper-scissors? | [
" No, but side-blotched lizards effectively demonstrate the same 'rock, paper, scissor' gene dynamics at the population level.",
"Are there any genes where the alleles dominate each other like in a game of rock-paper-scissors?",
"Hmmm, I have a 'sort of' answer! Though perhaps not mechanistically at the molecul... | [
"Cool question. It could only occur in a multi-allelic locus (in this case, multi means more than two). It is callled circular dominance and is an alternative to hierarchical dominance (also called serial dominance) - where, as you might, expect there is one most dominant allele, followed by an allele that is domin... | [
"Nitpicky point: The morphs are named based on the throat colors. The blotch in the species name is actually a black spot near their armpit.",
"Ahhhh, thanks for the correction! ",
"Why there's no female blue-throat. Any idea why that is?",
"Good question; technically there are! The ",
" allele is floating ... |
[
"What exactly happens to a person's behavior after a lobotomy?"
] | [
false
] | [deleted] | [
"Because a lobotomy is such a crude, destructive procedure, i don’t think there is a single straightforward answer. The tool used for the procedure could potentially cause all different forms of damage to the brain, though it seems it would be primarily the formal lobe that is affected. So it makes sense that we ty... | [
"I think you've covered it pretty well as to my understanding. Technically lobotomies \"reduced symptoms\" of mental illness but really just in the same way extreme sedation \"treats\" mental illness. Lobotomies also caused epilepsy, problems with inhibition and of course physical issues with the procedure (infecti... | [
"It depends on the part of the brain that's removed as well as the age of the person in question. ",
"There's a woman who had her entire right brain hemisphere removed to help with encephalitis (she's now an MS and a speech pathologist)",
". She was young enough (7 years old) when the procedure was performed th... |
[
"What causes musical chills?"
] | [
false
] | It seems in particularly emotional or moving parts of music most people tend to get chills throughout their body. What causes this? | [
"We have a subreddit for this!",
"http://www.reddit.com/r/frisson",
"Also a good article: ",
"http://arstechnica.com/science/news/2011/01/turns-out-that-music-really-is-intoxicating-after-all.ars"
] | [
"Thank you!"
] | [
"This is more related to why music has an emotional impact, but it goes into depth about what specifically causes a physical reaction in the body.",
"http://online.wsj.com/article/SB10001424052970203646004577213010291701378.html?mod=rss_Health"
] |
[
"Why does the hair of some children who were born blonde darken over time?"
] | [
false
] | When I was born, I had blonde hair. By the time I was five, my hair had gradually become very dark brown. I've seen this happen with many other children, too. Why was my hair not brown when I was born? What causes this change? | [
"Previously asked here ",
"http://www.reddit.com/r/askscience/comments/njgq4/why_was_i_born_with_blonde_hair_that_fell_out_and/",
" ",
"TLDR - different genes are expressed at different stages of one's life and factors such as disease and nutrition can affect gene expression. "
] | [
"So in theory could you take some sort of pill to change your hair color? "
] | [
"\"In theory\" is a tricky word here. So far, No, no pills can completely alter your genetic makeup, and this feat will likely be impossible for a while. The pill would need to have things like transcription factors that promote or repress specific gene expression, which will then dictate which proteins are made, w... |
[
"[linguistics] Is there a way to make sense of double negatives not canceling in some languages?"
] | [
false
] | I've known people who say things like "I ain't got no smokes", meaning that they DO have no smokes. Several people have told me that this is because a similar construction in Spanish is correct. Whether from Spanish or any other language, is there a way I can parse this so that it doesn't just seem wrong? | [
"This is what linguists call ",
". It's not a matter of negatives \"cancelling\" (this isn't math), it's a matter of multiple negatives adding up together to give a stronger, more emphatic, negation. In standard English, we usually use ",
" (and related words) to make our negations more emphatic, as in \"I don'... | [
"So, the description they give there is not great. The whole description of how English negations works there is not great. ",
"Let me clear something up, though: negative concord is not a mistake. People who use it are not making mistakes. It's simply how some people talk. It's rule-governed just like the negati... | [
"No, in a sentence like \"I never did anything\" or \"I didn't do anything\", with negator, ",
" is just a ",
"negative polarity item",
". It intensifies the negative meaning. In that context, it doesn't mean \"not none\". What I'm trying to get across is that the only level of structure at which the phrases ... |
[
"Are all metal elements able to be detected by a metal detector?"
] | [
false
] | [deleted] | [
"Yes. Nonmagnetic metals aren't detected as easily, but they will detect anything electrically conductive. They create an alternating magnetic field, which will induce a current in a conductor, which produces an opposing magnetic field. The magnetometer sensor can detect the change produced by the induced field. "
... | [
"This isn't because it didn't detect it, but because most security screening metal detectors have their sensitivity set only to detect relatively large metal objects to avoid getting too many false positives. "
] | [
"Hello, in answer to your questions :",
"(1) Yes, all transition metals and non-transition metals will be detectable (though metallic Sodium and Lithium would be an incredibly unlikely and unusual occurrence !)",
"(2)Providing the metalloid has a thermally induced electric field, which is very likely, then : ye... |
[
"That little dance your arms do when you slip, is that your body going into autopilot?"
] | [
false
] | [deleted] | [
"Well yes, since you don't do it voluntarily. It is an instinctive reaction to falling, trying to get a hold on anything that might help stop the falling or, failing that, at least brace the body for impact.",
"I think the evolutionary reason for this is the brain really dislikes hitting the ground, since that te... | [
"It's actually less of trying to hold on to something or bracing for impact. It has more to do with your body going into autopilot to try to prevent you from losing your balance. You know how when acrobats do the high-wire walking they will sometimes use a really long pole for balance? You arms in this case are bas... | [
"Imagine balancing a broom standing on end in the center of your palm, you have to walk around and always move your hand to keep it in balance. Now, imagine holding a finger out, laying the broom across it with the balance point on your finger. It is much more stable. You don't even have to move to keep it balance.... |
[
"Can anyone provide me with an explanation I can understand about the difference radio active terms?"
] | [
false
] | [deleted] | [
"Becquerels are a measure of the number of decays occurring. One becquerel is one decay per second. This doesn't necessarily tell you very much about its effects on anything else; it's just a measure of the activity.",
"A rad is 0.01 grays, and usage of rads is generally frowned upon in favour of grays, which are... | [
"Okay. There are different types of ionising radiation - commonly encountered examples include x-rays and gamma rays, beta particles (which are high-energy electrons or positrons released by beta decay), alpha particles (helium nuclei - two protons and two neutrons - released by alpha decay), but any electromagneti... | [
"Okay, So Becquerels are only in reference to the decaying particles per second in the environment. \nRad = 0.01 grays which is a more commonly accepted unit.\nThe last bit about sieverts I don't understand. Can you explain it further? "
] |
[
"Why are there different \"generations\" of cephalosporins?"
] | [
false
] | I know that certain generations are slightly better at combating gram-positive or negative bacteria than others, but it seems like plenty of drugs within classes are more efficient with certain types of infections without warranting the strange generational divisions. Why is this the case with cephalosporins? | [
"I'm from Europe and as I'm aware different countries will group the generations sometimes a little bit differently BUT:",
"1st Gen: generally cephalosporins with few structural variations except seen on the R group of the C7 position on the ring, these are drugs that will have limited effects against G- and ok r... | [
"Thank you for the rundown! Are their other drugs that are broken up like this? Is \"generation\" a common classification?"
] | [
"Not really, this is the only group in which the word \"generation\" is commonly used in practice. However many drug classes are modified to lessen side effects or enhance potency. Other drug classes usually get broken into subclasses bases on what makes them different, however it still may have a generation type ... |
[
"What is quantum gravity?"
] | [
false
] | What exactly is it and why is it important? | [
"We have quantum field theory, which tells us how very small things behave, and general relativity (gravity), which tells us how very big things behave. These generally don't overlap in scope, because small things are small and big things are big. However, in situations where both gravity and quantum effects are im... | [
"Right...but...what exactly does it do?"
] | [
"Quantum gravity is a theory, not a thing like a photon. It doesn't \"do\" anything in the sense of work. It is an concept, not a physical thing."
] |
[
"When you exercise, does your heart beat harder or just faster?"
] | [
false
] | Your muscles need more oxygen so the heart pumps blood through the body at a greater flow rate. I know your heart goes up, but does your heart beat with the same.. effort (there's gotta be a better word)? Or is every beat the same? Edit: Thank you all for your answers and insight! | [
"Both. To effectively increase flow throughout the body, both rate & strength need to be increased. Strength is simply how much your heart muscle is contracting... no different than any other muscle in the body.",
"However, it is possible to increase one without the other by targeting different cellular recepto... | [
"For those people who like medical terms... ",
"Heart rate --> ",
"chronotropy",
"\nStrength/Contractility --> ",
"inotropy"
] | [
"Yes, the heart does beat harder. It's called contractility.",
"Cardiac physiology is a complicated concept. It took almost a month of medical school to learn all the details.",
"Wikipedia has a basic introduction",
" which may get you started. Increased calcium levels and adrenaline are the main factors t... |
[
"How is mechanical energy created from chemical energy in cells?"
] | [
false
] | I understand the mechanisms by which ATP creates chemical energy. I can't seem to figure out how the chemical energy from the hydrolysis of the phosphate group is converted into mechanical energy to drive, say, a motor protein. I suppose I've always thought of the energy being released simply as negative ∆G. How is that ∆G converted into directional motion? | [
"If you're talking about the muscle sarcomere:",
"The binding of ATP to the myosin crossbridge causes a loss of affinity of myosin for actin leading to dissassociaition. ATP then undergoes hydrolysis to ADP and inorganic Phosphate (ADP + Pi), which once again restores chemical energy back into the system, extend... | [
"As an aside, an even more interesting reaction is electrical energy creating hormonal energy that then creates mechanical energy.",
"Depolarization of a neuronal synapse causes an action potential to propagate down an axon towards the neuromuscular junction. This leads to the release of Acetylcholine into the s... | [
"This sliding filament example is a great example of how chemical energy is converted to mechanical energy.",
"I suggest you try thinking of it like this, as I do. It may not be the whole picture but it satisfies some curiousity:",
"All chemical and physical states are merely potential energy. The very configur... |
[
"What could be consequences from the Amazon fires?"
] | [
false
] | Apparently some people have been burning the Amazon forest for weeks now. What will or could happen if they keep burning it? | [
"An excellent response. I'll just add to it that there is a current theory that of the Amazon loses as much as 5% more of its 1970 area it will cause a cascade effect which will result in the Amazon drying up and converting to a desert savanna. In other words, if too much more of the Amazon is destroyed the rainf... | [
"I cross-post this from a similar question on ",
"/askscience",
":",
"\nPartial deforestation of the Amazon and elsewhere has probably already ",
"altered rain patters across the world",
" and made the Amazonia more vulnerable to stress (such as wild fires). ",
"Climate change beyond two degrees is expe... | [
"average temperatures 4-5°C higher than pre-industrial temperatures",
"Is this even survivable?"
] |
[
"Is there a good \"do it yourself\" method to view the Venus transit safely?"
] | [
false
] | I'd like to see the transit, but don't have glasses or know how to acquire them. What can I use? | [
"Welding mask lens. Shade 14.",
"Welding shop: Maybe $15 for a pack of 3."
] | [
"In addition to the direct observation methods listed above, you can also make a pinhole viewer very easily.",
"What you need:",
"Cut a small (2\") hole in the center of one of the opaque squares. Tape a small piece of foil over this new hole. Poke a very small hole with the nail in the aluminum foil.",
"Now,... | [
"All welding masks ",
" to block UV, since the whole point is to protect your eye from the UV light coming from a welding spark."
] |
[
"Apparently our eyebrows are there to protect debris from falling into our eyes. Why/how would natural selection favor eyebrows, could they really save lives or make humans more likely to reproduce? Same goes for other seemingly insignificant parts of organisms."
] | [
false
] | [deleted] | [
"Iggy Pop once shaved his eyebrows before a concert because he thought it would look cool. Not long into the show, sweat was pouring down his face, blinding him and causing so much pain he almost had to stop the show. Afterwards his eyes were very swollen.",
"Now imagine you're a bald ape without claws, fangs, ... | [
"So in short you're saying \"eyebrows are not insignificant.\" OK, so he picked a bad example, but I think his question still stands unanswered. "
] | [
"They also play a key role in communicating with other humans"
] |
[
"Is there a cure or just a way to manage PTSD?"
] | [
false
] | Ive been told that people can manage PTSD but cant actually heal it. I just want to know if this is true or if it is curable. If it is curable, how is it possible? If it's not, why not? I couldn't find anything about this in the research I did. | [
"It depends on what you mean by \"cure\". That's not a term that's typically used in mental health treatment. What we can talk about though is response (meaningful reduction in symptoms), remission (defined by symptoms below a meaningful threshold) and no longer meeting diagnostic criteria.",
"What's particularly... | [
"Posttraumatic stress disorder as we currently understand it is a suite of symptoms related to extreme anxiety and distress, catalyzed by a single traumatic event or a series of traumas. These occur because the individual is unable to cope in a healthy way with the trauma(s) they have experienced. ",
"Most curren... | [
"EMDR therapy has also shown promising results, though it remains controversial due to the replication crisis in psychological research.",
"EMDR has a ",
" of replication over decades. There's certainly controversy around it including post-hoc explanations for its mechanism of action and studies showing that on... |
[
"Regular pentagons tile in spherical space. There are 15 known irregular pentagons that tile in flat space. Is it true that *any* pentagon will tile in some space with homogeneous curvature?"
] | [
false
] | null | [
"for the purposes of tiling, aren't polygons defined in terms of the relationships between their various angles? A regular pentagon in some arbitrary space would be a 5-sided polygon whose internal angles are all equal. ",
"At least, defined thus, is it true that any 5-sided polygon will tile in some space with h... | [
"What a shape is depends not only on its side lengths and internal angles, but also on the space it's embedded in. It wouldn't be correct to say that a regular pentagon in spherical geometry is the same shape as a regular pentagon in Euclidean geometry, because they have different internal angles. It's obvious enou... | [
"You can regularly tile the sphere with 4, 8, or 20 geodesic triangles. Since the tilings have 3, 4, and 5 triangles meeting at a point respectively, it's clear that the vertex angles of the geodesic triangles in the different tilings must be different.",
"What's a \"space with homogeneous curvature\"?"
] |
[
"Should I rush to re-open a closing door or should I just open a closed one?"
] | [
false
] | In a food court, there are 4 adjacent self closing doors. I have noticed that people run to re-open a closing door behind someone who had just went through. I think the intuition is that a half open door is easier to open than a closed one. But the physics in my head seems to think that opening a closed door uses less energy. But when I work it out on paper, it seems to give me equivalent efficiency (equal efforts) for both situations. Here is my breakdown Situation 1 - Closing door: One must first do work in order to bring the closing door to rest before doing the work to reopen it into the open configuration. Situation 2 - Closed door: Work must be done to bring the stationary door into motion and into the open configuration. The assumption I made in my personal calculations is that the open configuration is twice the angle at which the closing door is brought to rest. So... is it equal? My mind's telling me no. But the maths... The maths it telling me yeaaah. | [
"Buildings are slightly positively pressurized, the additional pressure on the door can make an inward swinging door more difficult to open, initially, before the \"seal\" is broken. A reasonable target is 0.02in-wc, which is about 0.0007psi. While this is a small number, over a large exterior door it can be a few ... | [
"When OP said",
"One must first do work in order to bring the closing door to rest before doing the work to reopen it into the open configuration.",
"I think he meant",
"the force/momentum of the door as it is closing. This force must be overcome in order for the door to rotate the other direction."
] | [
"Note that these assumption are not valid for all doors",
"Yeah, I don't think that's a good model. The mechanisms that close a door have a spring component, but they also have a piston whose job it is to prevent the door from moving too fast at any point. It can be roughly modelled as the force it provides being... |
[
"In this gif for what reason do the gas bubbles sink?"
] | [
false
] | Here's the . I imagine if it went on longer the bubbles would rise but I can't imagine any reason they seem to sink unless the perspective is skewed and the gun is pointed more downward than I think. | [
"Keep in mind the huge bubble that comes out when the gun is fired is very hot. It's cooled nearly immediately, greatly reducing the volume of gas. ",
"What you see going downward is the particulate/smoke from the explosive in the ammunition, which is sinking in the water as one would expect. Toward the end of th... | [
"Most of that bubble isn't bubble at all, it's ",
"cavitation",
" caused by the bullet exploding out of the gun creating a momentary vacuum in the water. It collapses right after and dissipates. "
] | [
"What you see going downward is the particulate/smoke from the explosive in the ammunition",
"I really don't think it's that easy. I see the following:",
"After the bullet leaves the barrel, the porpelling gases form a bubble in front of the gun. The gases compress (like you said) but also mix with the water to... |
[
"Is Marinol less medically useful/potent than \"medical marijuana? Why do I never hear about it?"
] | [
false
] | null | [
"Marinol is synthetic THC. Medical marijuana differs because there's many different cannabinoids that work in conjunction with THC in ways we don't fully understand to produce the desired therapeutic effect.",
"I hope this analogy works. Lets say milk is illegal, but pure caesin (protein in milk) isn't. You want ... | [
"Good answer. ",
"Cannabidiol",
", for example, has been shown to ",
"work as an anti-psychotic",
" (pdf file)."
] | [
"I think there's a few good answers to this. As a caveat, I've not used marinol in any of my patients, nor have I ever had it myself. I haven't used marijuana either, because it's illegal, and I like having a medical license.",
"Like ",
"hullabazhu",
" pointed out, there is more than just one active chemical ... |
[
"How can volcanoes form where there are no plate boundaries?"
] | [
false
] | In high school I've learned that volcanoes form on plate boundaries which I understand. But what I've been thinking about is how can volcanoes form where there are no plate boundaries. The main example I'm oging to use is in Edinburgh, where the Edinburgh castle is build ontop of an extinct volcanoe. How did that volcanoe form if there are no plate boundaries in Scotland? | [
"Couple of options:",
"1) ",
"Hotspot volcanism",
" where volcanoes erupt above a localized zone of anomalously hot mantle. These are most likely related to ",
"mantle plumes",
", but a few holdouts still argue for alternative mechanisms. Regardless, hotspots can occur near plate boundaries (e.g. Iceland)... | [
"This",
" write up does a pretty thorough job of going through some of the arguments. The short version is that it's complicated and arguably the simple vision of plumes that appear in intro textbooks probably don't exist. The question as to whether something functionally like a plume but a bit more messy exists ... | [
"Re: 1, how do the holdouts still manage to hold out in this? I was under the impression that in at least the case of Hawaii mantle plumes were pretty decisively supported. Since the whole motivation for alternatives was to simplify the model, that would seem to kill that motivation.",
"What am I missing?"
] |
[
"What is PWM and why is it used in driving an inductive load?"
] | [
false
] | null | [
"I worked with pwm drives for many years. They are used to drive inductive loads as a way to vary both voltage frequency and current seen by the load. ",
"They are basically just used with 3 phase motors so I will talk about them. In a regular off the line start, a 3 phase motor will typically produce 150% full l... | [
"Pulse Width Modulation is used because it is an efficient way of synthesizing a variable voltage to a load.",
"PWM amplifier transistors act as switches, they are either 'on' or 'off'. When 'on' there is very little voltage across the switch and a lot of current through it. When 'off' there is a lot of voltage a... | [
"(I'll try to tackle this one, even though I'm still learning myself) Pulse Width Modulation is the process of changing a waveform's duty cycle. The periodic signal you get from a function generator is typically 50% by default, but that can be modified. A 10% duty cycle would be a signal that's on 10% of the period... |
[
"What makes your steering wheel \"level out\" when you press the accelerator?"
] | [
false
] | Ever since I started driving I noticed that if you're turning and you accelerate after completing most of the turn, the steering wheel will go back to being straight without you having to rotate it yourself. Why is this? | [
"Caster causes a self-centering force."
] | [
"yes, but i've noticed it in my all wheel drive cars as well"
] | [
"yes, but i've noticed it in my all wheel drive cars as well"
] |
[
"Why do some chemical reactions need catalysts (such as potassium permanganate), and what does the catalyst do if it is not used up?"
] | [
false
] | [deleted] | [
"Catalysts do take part in the reaction if you consider the mechanism, or overall sequence of steps, involved in a reaction instead of just the overall reaction. Any reaction that involves 3 or more reactant molecules (even if some of them are of the same type) proceeds via a multistep mechanism. A catalyst is a re... | [
"In general when we write out a chemical reaction, we are writing a very brief summary. Most reactions have very many steps required for the reactants to become the products, often involving multiple intermediate structures. If a reaction does not occur spontaneously very quickly, it is often because one (or more) ... | [
"interesting!! thanks for the detailed response."
] |
[
"In a packed grocery store with long cashier lines, is it better to choose one at random?"
] | [
false
] | So I got stuck today for 20 minutes in a cashier line, and it got me thinking about the optimal way to choose a line. Whenever a customer had finished shopping he would run through all the lines to find the shortest one. But here I was thinking, if every customer before me has searched for the better line, then the lines are more or less equally long. So the best option would be just to pick the nearest line and not bother looking for anything better. So I know this obviously has been thought about someone before. And while I know a little about game theory, I have no idea how I would search for such a concept. Does anyone have somewhere to lead me to? Could anyone explain under what area of economics/mathematics this would fall into? | [
"Personally I evaluate the amount of products in each persons cart, I'd rather get in the line with five lightly loaded carts than two heavily loaded ones. Also I've found that younger to middle aged (20-35) cashiers seem to be a bit faster. Several elderly persons in a line are usually a red flag as they tend to ... | [
"When you pick a line, you have to wait until all the people who were on the line before have finished. How much that takes depends on how many people are on the line and the products they have. Thus, if you choose the line which takes less time, you will wait less. That's it. Your initial intuition was right.",
... | [
"5 lightly loaded carts means 5 payment exchanges, increasing the odds of a check or somebody deciding to wait until presented with the total before fumbling through a cavernous bag for a purse/wallet. "
] |
[
"What is the math behind the microgravity on the ISS?"
] | [
false
] | I've read that the reason astronauts are weightless on the ISS is because the centrifugal force is equal to gravity. Can anyone do the math to back this up? | [
"Gravity is fictitious too! ",
"Sorry for the lame humor, just want to point out that \"fictitious\" doesn't mean \"non-existent\", it means ",
"\"dependent on your frame of reference\"",
". Specifically, inertial versus non-inertial.",
"However, whether your frame of reference includes fictitious forces or... | [
"1.Set coordinate system to earth",
"2.Idealize the ISS as a point mass, neglect friction and gravitational influences of other planets, approximate that the orbit of the mass is a perfect circle around earth",
"3.The tangential speed of the mass is kinematically preset",
"4.Cut the mass free and draw in all ... | [
"That is an equivalent way to say the same thing. From a fixed reference frame, they're accelerating towards Earth. From a rotating reference frame, gravity and centrifugal force are cancelling out."
] |
[
"I'm getting a lot of conflicting answers. Are there any real benefits of drinking alkaline water?"
] | [
false
] | null | [
"Everything I have ever seen besides the propaganda, indicates that it is a bunch of new age bull. ",
"http://www.chem1.com/CQ/ionbunk.html",
"http://message.snopes.com/showthread.php?t=13815",
"http://www.apswater.com/article.asp?id=198&title=Alkaline_Water_Hoax_-_It_Is_Simple_Science",
"."
] | [
"Your body has natural pH buffers. You can't improve that or change how they function. "
] | [
"No. The pH of the water you're drinking is not important so long as it is neither too high nor too low, which would cause ulcers. The stomach makes short work of any alkalinity in the water and takes it to a pH of about ~2 (depending on what you just ate or drank). It then enters your intestine where it goes up... |
[
"My apartment offers free water but not electricity. Would it be possible to use the water to generate enough power for my apartment? (eg. bathtub water wheel)"
] | [
false
] | I have a pretty standard one-bedroom apartment and would need to power a refrigerator, 3 room lights, a laptop and other standard appliances. Is there any shot I could harness the power provided by the free water to meet my electricity needs or is it simply not enough energy? Also, of course the apartment would probably catch on and kick me out if I was running water 24 hours a day, so lets ignore that reality. | [
"Let's say you're using your bathtub. I looked it up, bathtubs put out about 4 gallons per minute. 4 gallons of water is 15 kg. I think this is higher than reality, but let's say the water falls 2 feet from the faucet to the ground. The potential energy then is m*g*h, so the amount of potential energy over a minute... | [
"Typical residential water pressure is about 3 to 5 ATM and typical flow rate inside a residential home is somewhere around 10-15 gal/min, about 38-57 l/min. This is assuming you could source the water from the pipes rather than a faucet. The flow from a faucet will be much less, maybe 1 to 3 gal/min. ",
"Mult... | [
"Houses have pressure regulators. This is why if you live far below the water tower, water still doesn't explode out of the faucet. Regardless- we know the gallons per minute of most bathtubs, and how many gpm it puts out is determined by the pressure, so we are taking all of that into account. "
] |
[
"Do taller and shorter people have higher and lower heart rates than people with average heights?"
] | [
false
] | It's late (as of typing this) and I'm wondering stuff.. Also I guess an extension of the question is "Are taller people more susceptible to high blood pressure?" | [
"Cardiac tissue is post-mitotic (the cells can no longer divide) there are other organs like this (brain) but the main problem with people who get extremely tall like pituitary-giants is that while the rest of their body keeps growing their heart reaches a maximum size relatively early in development. Their hearts ... | [
"Working at a hospital for quite a while I can say that generally heart rate differs from patient to patient depending on their level of activity. Someone who does a good amount of aerobic activities and exercises will generally have a lower heart rate than someone who doesn't. The normal heart rate being 60bpm-100... | [
"Thank you for your answer. I learned from it."
] |
[
"Is molecular movement really random?"
] | [
false
] | [deleted] | [
"The motion of atoms in many situations can be described classically, in which case it is indeed deterministic. However, it may still be ",
", meaning a small difference in initial conditions will cause a very different result as time goes on, making it impractical to predict the precise paths of a large number o... | [
"Classical mechanics is not ",
" deterministic, but many classical systems are. Classical collisions between particles are deterministic."
] | [
"Classical mechanics is not deterministic",
". In addition to that, while quantum mechanics is not deterministic, it is unitary, unlike classical mechanics. Unitarity means that you can always run the system in reverse and get back to the initial state. Unitarity is not guaranteed in classical mechanics (though w... |
[
"Why are there no CMYK colored Pen sets?"
] | [
false
] | Hi, In subtractive color / printing yan, agenta, ellow and blac are used to create all colors on a white background. These colors act as a filter to the colors in ambient light and thus the correct CMYK filter combination shows the desired color. Why isn’t CMYK a readily available combination for pigment colors such as pens, paint and the like? | [
"It seems like your theory is if someone had these four colors they could create any color they want on paper.",
"The problem is, to create a certain color, you would need the ability to very precisely deposit an exact ratio of the necessary base colors. Pens allow ink to flow at a generally consistent rate. Yo... | [
"https://www.amazon.com.au/Set-Primary-Ecoline-Liquid-Watercolour/dp/B07C5QBS59",
" ",
"https://www.amazon.com.au/Holbein-Artists-Gouache-Primary-Mixing/dp/B001GQ37TI"
] | [
"They can be mixed. I said \"You would have to mix and dilute the inks before drawing with them. \". Unless you want highly saturated color, of course."
] |
[
"Do I understand correctly that what we call color \"green\" is actually two different things?"
] | [
false
] | One is the light with wavelength corresponding to green, and the other one is mixture of wavelengths corresponding to yellow and blue. Then on the other hand, there may be some other colors that if you mix them you get green. Perhaps all those pairs of colors which are equidistant from green on the color spectrum. | [
"Colour is entirely a product of perception. You can have a photon of one wavelength, or photons with a mixture of wavelengths, activating the receptors in your eye that lead to the perception of \"green.\" In that sense, the colour green is only one thing."
] | [
"So you're referring to two different things. Green light is green light, and it spans a well-defined range of wavelengths of light. However, you're talking about combining colors to get green.",
"So the color of the light we see depends on ",
" we combine the colors. If we were to take a blue light and a ye... | [
"\"The reason that you see yellow and blue in the first place is because each paint reflects light of those colors. Anything that's blue is absorbing the orange light, and anything yellow is absorbing indigo light. When you mix yellow and blue, they absorb all visible colors except for green\"",
"Just what a quic... |
[
"What do ants do at night? Sleep?"
] | [
false
] | I don't know what is the correct flair to use. | [
"Ant colonies are like human cities. And just as human endeavour continues 'round the clock, so does the activity of the humble ant colony. The bulk occurance of human activity however skews sharply towards daylight hours, with only a fraction of the population engaging in e.g. night-shifts, or panicked essay-crisi... | [
"Thanks this is fascinating."
] | [
"Do they have a spot where they go to sleep or do they just sort of drop down somewhere and the others crawl over them?"
] |
[
"If going at the speed of sound creates a sonic boom, then hypothetically, if a light source was accelerated to the speed of light, would there be a big \"light wave\"?"
] | [
false
] | null | [
"So, we can't answer the question of \"what happens if a light source is traveling at the speed of light\" because things with mass can't travel at the speed of light, and the equations that would answer this question \"blow up\" at the speed of light, but there are two things which are related to this question whi... | [
"While slow-light jocks can do some crazy things in the lab, for most solid and liquid materials it’s 20-50% slower. The ratio of light speed on vacuum to light speed in the material is the ",
"index of refraction"
] | [
"and some materials that can be significantly slower than c",
"How significant are we talking here? Orders of magnitude?"
] |
[
"If spacetime \"isn't a thing\", but just defined by the distances between events, how can it be curved?"
] | [
false
] | This has been bothering me for a while. It comes up a lot that it's incorrect to talk about the "fabric of spacetime", and I've heard it said many times on this forum that space and time aren't actual physical things. If this is the case, then how does it make sense to talk about spacetime being curved? If it's not a real thing, but only exists conceptually when measuring the distances between physical phenomena, then how does it make sense to talk about gravity being the curvature of this thing that "doesn't really exist"? To my simpleton mind it seems like there are two options to describe the situation of two objects coming closer together due to gravity: The objects are directly interacting with one another (with a force as Newton thought). The objects aren't directly interacting but are embedded in some "medium" that is affected by their presence in some way which eventually changes their orientation with respect to one another. But if there is no medium, what is actually being affected by the objects' presence? Please someone help me. | [
"there are no absolute measurements of distance and time. There are only measurements relative to some observer. This observer may be moving relative to another observer, or may be near the presence of energy (maybe in the form of mass). The way in which these measurements vary with observer location is ",
" by t... | [
"http://www.reddit.com/r/askscience/comments/itehf/can_someone_explain_the_curvature_of_space_time/",
"Basically, the curvature of spacetime isn't the kind of curvature that things have. It's a specific mathematical kind of curvature, which is just a property of the way that different points in space are connecte... | [
"If this is the case, then how does it make sense to talk about spacetime being curved?",
"Geometry, is the answer. It's not really possible to elaborate on that ",
" without equations, which I'm loathe to try to typeset, but suffice to say that curvature is a property of geometry, and we're defining geometry h... |
[
"Is it negative to expose yourself to bacteria/fungi/etc?"
] | [
false
] | [deleted] | [
"Most bacteria on fruit is the 'good' kind that won't hurt you. That's not the reason you are supposed to wash them though. You wash them to get the pesticides off. "
] | [
"I'd say as far as fruit and what not goes, you're OK. An immune boost if nothing else. ",
"As far as meat, however, lots of weird stuff can happen when parasites enter the picture. Read about neurocysticercosis if you want a neat little picture. ",
"Also there is such a thing as an infective dose, which var... | [
"Despite the best efforts of factory farms, not all chicken is a writhing mass of salmonella. You've been lucky enough not have ingested enough.",
"For fruit, I'd be more concerned about pesticide."
] |
[
"If I stood in an empty field away from civilization, would I be able to hear an earthquake?"
] | [
false
] | Every video of an earthquake that I've ever watched is shot inside or near buildings/civilization and the accompanying sounds are much like what you'd expect: Glass shattering, people screaming, etc. Would an earthquake make any sound that I could perceive if it happened right below me? What might that sound like? | [
"You might. As you've correctly surmised, teasing out what if any sound produced during an earthquake is generated by the seismic waves as opposed to cultural items (i.e. buildings, etc) breaking is difficult. The USGS has a ",
"discussion of reported sounds that occurred along with earthquakes",
". The sound a... | [
"You would, provided it's above a certain strength. Depending of what substrate you are on (rock vs mud), you would probably heard anything above 5.5 to 6.0. From previous experience, it sounds like a deep bass rumbling/growling.",
"You might yet still hear peripheral noise from trees falling and/or shaking, or ... | [
"I think the other two posters pretty much covered it, but I wanted to add something that I think about often: since the slowest seismic wave, the Rayleigh wave, travels about ten times faster than the speed of sound, it's pretty much impossible to \"hear\" an earthquake coming. By the time you can hear it, it's he... |
[
"How does the remaining area of a regular polygon with an incircle change as you increase the number of sides?"
] | [
false
] | If I have an incircle of an equilateral triangle with radius r there will be a certain amount of area outside of the circle but inside the triangle. If I take the same circle and create a square around it so that it is the incircle of the square there are now four areas outside of the circle that are smaller than the three left in the triangle. Does the remaining area have any relationship with the area of the triangle? Does the relationship continue with polygons of increasing side #? | [
"If we are inscribing the circle, which has radius R, then the ",
"apothem",
" of the polygon is R. The ",
"area of a regular n-gon with apothem R",
" is nR",
"tan(pi/n). The area of the circle is pi*R",
". So the area of what is leftover is",
"There isn't, then, any \"nice\" relationships between the... | [
"Okay then, thanks! So as the equation approaches infinity the remaining area does reach 0, right? Since then you would be ever-approaching a circle."
] | [
"Yes. You can see the graph ",
"here",
"."
] |
[
"What would happen if you built a bridge around the earth and broke all of the legs simultaneously? would it remain floating?"
] | [
false
] | assuming it is evenly distributed so that one part isn't heavier than the other would it just float there since it's being pulled equally from all parts? ignore the viability of building such a bridge, i'm more interested on how the physics aspect works. | [
"It's in unstable equilibrium. If a part is tiny bit closer to the Earth, it will be attracted more strongly and will fall. The opposite side, attracted less strongly, will rise."
] | [
"In an idealized setting, where the bridge and the pull of gravity is perfectly symmetric, it would indeed stay floating. But this state is known as an \"unstable equilibrium\" because the tiniest deviations from symmetry, which always exist in the real world, would cause the bridge to fall in one direction or ano... | [
"If done in real life no it would not, or at least not for long.",
"But:",
"Presuming a simplified earth with equal gravity and no other forces such as wind or snow.\nPresuming the bridge type is able to withstand the pressures from \"holding itself up\".",
"Then yes, the bridge would remain \"floating\". "
] |
[
"How do blood clots form?"
] | [
false
] | What's the process. What's the material. How it's done. | [
"Let's start with what a blood clot is; a blood clot, or Thrombus is a sort of plug or patch that stops bleeding, and it's composed of two things; Platelets, and Fibrin. Platelets a normal component of the blood, along with White Blood cells and Red Blood cells. Like red blood cells, they lack a nucleus; they're mo... | [
"I'm a bit sleepy and will give a more detailed answer in the morning but your body has a specific set of steps (a cascade) that it goes through to stop bleeding and start the healing process. Hemophiliacs are deficient in one or more of these steps so the chain is incomplete, and there is a serious risk of death f... | [
"The process of blood clotting is triggered whenever flowing blood is exposed to certain substances. There are many different such substances, which are called thrombogenic because they promote formation of thrombus (another name for a clot). Many thrombogenic substances are located in the skin or in blood vessel w... |
[
"How does dehydration cause edema?"
] | [
false
] | so, as far as i know, dehydration means lower blood volume, which means lower blood pressure, while edema is mostly caused by high blood pressure in the veins. | [
"It’s more rehydrating after being dehydrated that can cause edema than being dehydrated itself. The body tries to pull too much water back into your cells when you take in water after being dehydrated which can result in swelling and, in more serious cases cells bursting."
] | [
"Edema can be caused by lots of things. Dehydration doesn't cause edema, but it's possible for some other underlying problem to cause both. For example you could have an electrolyte imbalance. ",
"It's also possible for edema to cause a kind of dehydration. If fluid is collecting in your tissues as edema, that me... | [
"Thanks!"
] |
[
"Does the presence of a measurement device alone effect particle behaviour in quantum physics experiments?"
] | [
false
] | This question is coming from someone with no understanding of quantum physics other than youtube videos, but say you were to place a camera that was not on in the experiment, how would that affect things, etc.? | [
"You might have the idea that \"observation\" somehow collapses quantum wavefunctions. In reality, it's actually interactions with a macroscopic object that cause the wavefunction to become decoherent - essentially to collapse. ",
"So it doesn't matter if the camera is on or off, as long as it's interacting with ... | [
"IANAQP but my understanding is that if you measure something then you have extracted some energy from that system, in the form of light, electric potential, etc. so that means that the system is different. In the macroscopic environment you can usually get away with some kind of measurement (energy extraction) tha... | [
"Let me be very careful, because this is the step that sends people into crackpot-ism more quickly than anything else. We create a fundamentally different path for the light (or whatever) to travel through by putting a detector there. The type of experiment we perform will select what result we get. But this has ",... |
[
"How does the heat produced in a reaction affect the rate of that reaction?"
] | [
false
] | For example, in chemistry, we were discussing reaction constants and my teacher said that the constant only applied at a certain temperature. My friend asked then, how do reactions that feature change in heat over time affect the reaction constant? | [
"The formula that relates reaction rate constant with temperature is the ",
"Arrhenius equation",
". As temperature goes up, the rate of reaction increases.",
"Note that this is purely in terms of the rate constants (i.e., kinetics). Temperature can also affect the thermodynamics of the reaction - for example... | [
"Like the other two said, the Arrhenius equation for the rate constant changes with temperature. However, in most real reactions, the change in temperature is also dependent on the rate of reaction, in addition to the heat capacity and heat of reaction, which are also dependent on temperature. So all of these fac... | [
"oh okay thanks!"
] |
[
"If antimatter and matter destroy eachother on contact, how can lasers be used to suspend antimatter with out it being destroyed?"
] | [
false
] | null | [
"Antiparticles can't annihilate with photons, if that's what you're getting at."
] | [
"A particle can only annihilate with its own antiparticle. And photons are their own antiparticles. So if you're storing anti-atoms in a trap, you can shoot photons at them, and there won't be any annihilation."
] | [
"Oh neat I thought they could annihilate with any form of matter, interesting to know that it's only there own antiparticle. Thank you"
] |
[
"How does white protective suits, goggles and blue gloves protect you from radiation?"
] | [
false
] | I was reading this article when I began to wonder about this question, but I have pondered this previously. | [
"It's mostly so you don't touch or breathe the radioactive stuff directly, and so you don't take them home with you later either.",
"Most shirts are enough to stop alpha and beta radiation. Some suits that are lined with dense materials can stop some gamma radiation as well."
] | [
"Exactly this. While some sorts of radtion (gamma, beta) can easily pass through your suit, it is not a good idea to have things like radioactive dust on your clothes. The suit makes sure that once you take it off, and leave the \"danger zone\" (or whatever), you leave behind any radioactive things that may have ... | [
"The terms are actually archaic, but stick with us all the same. Gamma rays are just really high energy photons. Light. Beta rays are electrons or positrons, but generally electrons (usually the positron kind is Beta",
" ). Alpha rays are He",
" nuclei. ",
"Nuclei decay by alpha decay or beta decay to become ... |
[
"Why is it that when I chew gum for a long time, at one time it stops being chewy and elastic and becomes a granular, fibrous lump that's much softer? This transition happens pretty rapidly, in maybe a couple of seconds."
] | [
false
] | Anyone else know what I mean? Or do I have messed up oral chemistry? Either way, can anyone explain? | [
"I've once read this somewhere and it had to do with components leaving the ",
"Gum-Base",
" just like the favor leaves the gum.",
"\nI don't see how this could happen in a moment, and from my own experience I don't recognize such rapidness in the change."
] | [
"It could have something to do with the biochemistry of your saliva. Saliva natually contains enzymes that break down whatever we are trying to eat. Gum is one of those things that is extremely tough for our repitoire of enzymes(or even stomach acid) to break down.",
"As far as your case goes, you might just have... | [
"Happens to me too. It becomes less cohesive as well. It becomes very sticky but tends to separate very easily. I've noticed that it seems to be certain brands that will do this as well. For me, the main offender is Juicy Fruit."
] |
[
"How do astronomers determine the radius of the moon?"
] | [
false
] | null | [
"From basics, we can determine how far away the Moon is by knowing how big the Earth is and then timing the progress of the Earth's shadow on the Moon during a Lunar eclipse.",
"https://www.universetoday.com/91120/do-it-yourself-guide-to-measuring-the-moons-distance/",
"Since we can measure the Moons apparent s... | [
"Lasers, you shoot them at the moon and catch the reflection. Measure the round trip time gives you the height to your spacecraft.",
"Do that often enough to cover the whole surface and the average is your lunar mean diameter."
] | [
"You can determine it by knowing how far away it is and by how big it looks."
] |
[
"What is the oldest known biological ancestor we have, and do we have a name for it?"
] | [
false
] | For example, we know more recent ancestors like Homo Habilis and Homo Erectus, but what's the oldest known ancestor? Something with fins? Some kind of bacteria? Who is our oldest relative? | [
"There is the Last Universal Ancestor, which is the organism all extant life evolved and branched from. It was probably bacteria-like. Or are you looking for a more specific answer?"
] | [
"Check out this website if you want to trace your ancestry (roughly) back to the last universal common ancestor: ",
"http://tolweb.org/tree/"
] | [
"I'm just taking the best knowledge I have, someone with a better education/knowledge of these things might be able to answer it better.",
"The oldest known ancestor to humans is ",
"Sahelanthropus tchadensis",
", an extinct hominid dated to roughly 7 million years. It is possibly one of the first species to ... |
[
"If waves can be disrupted through destructive interference, and light travels in waves... Why can't we disrupt light?"
] | [
false
] | I used to work with communications equipment in my last job. One of the things you could do to radio waves was broadcast at the inverse frequency to disrupt the signal. You can do similar things with sound, Wi-Fi etc. But why can't we do this with light? Is it possible? | [
"In theory we can, visible light works almost in the same ways as radio waves. In practice it's more tricky, since we would have to precisely match all the frequencies and since they can be quite chaotic from every day sources, it's really hard. But in a lab under controlled settings it's just as with the radio wa... | [
"I can't think of any direct applications involving of disrupting all light from a source, it's just to much work for blocking out some light. But we can use the interference effect of light for many different things, for example shining laser through a lattice or crystal and by looking at the subsequent interfere ... | [
"Well thanks for answerimg my question. Enjoy gold"
] |
[
"Are there any species of biota native to North America that are invasive or destructive in other parts of the world?"
] | [
false
] | I live in the Appalachian mountains and kudzu is a real problem in my neck of the woods/world. I was just wondering if any native North American species caused problems elsewhere in the world. | [
"Nessie doesn't mention ",
"Muskrats",
", which are a big problem in the Netherlands because they damage our dikes. We spent about 30 million euro each year trying to exterminate them (and failing miserably)."
] | [
"Bass and American crayfish in Japan. ",
"Here's the full list for Japan:",
"http://www.nies.go.jp/biodiversity/invasive/index_en.html",
"Cane toad in Australia",
"http://en.wikipedia.org/wiki/Cane_toad",
"Grey squirrel in the U.K. ",
"Here's a roundup of 10 species from National Geographic",
"http://... | [
"Another example is black cherry in Europe."
] |
[
"How close could a person get to the sun before they burned up completely?"
] | [
false
] | null | [
"Without the protection of the Earth's atmosphere, you would burn up right here. This is a big problem on the space station, where ",
"the sun heats the facing side to 250 F (120 C)",
". So the distance to which you can approach the sun is a function of your ability to mitigate the radiation. I know that's not ... | [
"Yes, I watched this based on recommendation on AskScience too. Some parts are not really accurate, the director took some 'artistic liberties'. Satisfying nonetheless."
] | [
"Yes, I watched this based on recommendation on AskScience too. Some parts are not really accurate, the director took some 'artistic liberties'. Satisfying nonetheless."
] |
[
"Can long term sleep deprivation cause any permanent damage?"
] | [
false
] | [deleted] | [
"Is it possible that I've sustained any permanent damage?",
"The more common long-term sequelae of chronic sleep deprivation are hypertension and other cardiovascular issues. Since I'm not a cardiologist, I won't go into more specifics, but the heart is shown to take a lot of stress from not going into rest mode... | [
"I've been told by a psychologist that a few days without sleep and you start risking psychosis. While that psychosis may not be permanent, it could start a big snowball of problems."
] | [
"There are the psychological issues as mentioned below. Also, you would be exhausted and, in the long term, risk passing out or collapsing from said exhaustion. There is the possibility of injuring yourself some way there. Mental functions such as the ability to make sound, logical decisions also take a dive when y... |
[
"If there are magnetic field lines are there gravitational field lines also?"
] | [
false
] | If there are what is the significance of them and how do field lines relate to the waves in electromagnetic and gravitational fields? | [
"Yes. Similar to how magnetic field lines give some indication of which way a dipole will orient at that location and how strongly, and electric field lines indicate the direction of force a positive charge would experience, gravitational field lines indicate the strength of gravitational force a mass would experie... | [
"Iron filings act as little magnets themselves, so they tend to repel each other. This effect isn't as strong as that of the main magnet. In this way, the filings line up with the field and separate from each other to create the lines. Gravity, on the other hand, clearly does not produce this effect.",
"Although,... | [
"You can easily see gravitational field lines in the same sense that you can see magnetic field lines!",
"Simple hold a rock on a piece of string and it will point straight down. That's the gravitational field line!"
] |
[
"So I know about the colors of urine (dark means dehydrated), but what does cloudy mean?"
] | [
false
] | My only thought on this is when it happened my previous meal was a bag of pretzels, but this has occurred before in a morning urination. Is it just my body expelling excess salt? | [
"Cloudiness is caused by proteins, crystals, or cells in the urine, which are all normal. Cloudy urine isn't pathologic in itself. It also depends on ",
" cloudy it is, which you can't tell by looking at it in the toilet. When we look at it in the lab, there are 4 grades of turbidity: Clear, hazy, cloudy, and tur... | [
"There are specific grades of cloudiness:",
"This is done with a well mixed specimen, in a clear container that is of a specific size, and is viewed against a white background with text, grid, or a series of lines.",
"The cloudiness is not specifically related to diet. Contamination from the environment can als... | [
"There are specific grades of cloudiness:",
"This is done with a well mixed specimen, in a clear container that is of a specific size, and is viewed against a white background with text, grid, or a series of lines.",
"The cloudiness is not specifically related to diet. Contamination from the environment can als... |
[
"How is there economies of scale with both diminishing costs and returns?"
] | [
false
] | If both marginal costs and returns go down as output increases, how can we have a lower marginal cost per unit of production? | [
"Since you haven't yet gotten an answer, I'll respond even though this is outside my main area of study.",
"Economies of scale and diminishing costs happen in different regions of production quantity. For a very simplified model, ",
"see here",
". Increasing output from Q to Q2 causes the average cost to dr... | [
"I hope I understand your question properly. But I hope this answers it. I'll try to keep it as simplistic as possible.",
"Marginal cost, aka the cost of producing one more unit decreases with an increase of production. But at the same time the supply of the product increases and causes the price of the units dow... | [
"Oh, thanks a lot."
] |
[
"Have the effects of hallucinogens on comatose patients been studied?"
] | [
false
] | [deleted] | [
"Not something that is going to happen. There are numerous restrictions on human testing, and with comatose patients there isn't any way of getting them to sign a waiver after the coma has happened, and even if they did prior to the incident the family could push for power of attorney and put a stop to it."
] | [
"And yet at the same time the Milgram experiment, as with the Stanford Prison experiment, were incredibly useful in exploring human nature and opened up a whole new world of thinking and are still being discussed as relevent so many years later. Research ethics are absolutely important, and protecting the experimen... | [
"Ethics in research is important. Consider the Milgram experiment and then think of how you'd feel if you were convinced to torture a person until they died."
] |
[
"Why don't the bubbles (head) created when pouring a beer dissolve quickly like bubbles produced when pouring pop?"
] | [
false
] | If you pour a carbonated drink straight down (Pepsi, let's say), it bubbles up at the top, but these bubbles quickly melt away. A beer's head however dissolves much slower. Why is this? Similarly, when you pour pepsi onto ice cream in a glass when making an ice cream float, the bubbles don't melt away at all, why is this? | [
"Beer, unlike soda, contains a melange of proteins from the grains and the yeast. Many of these proteins are amphipathic (i.e. they have sections that are hydrophilic, and sections that are hydrophobic, similar to soap), and, similarly to soap, these proteins help to stabilize gas bubbles. (I hope that someone ca... | [
"To add changing the cereals used in the beer will actually change the properties of those bubbles. Beer is, in the simple case, made with partially germinated, roasted barely; adding 10% wheat will actually cause bubble retention. "
] | [
"Because of the proteins and additives, beer has a much higher surface tension than water or soda. The higher surface tension stabilizes the bubbles in the foam for longer lasting head. A common additive to stabilize head is ",
"aliginate",
".",
"Here's a good explanation of the relationship between surface t... |
[
"If chips are square why are they produced in circular discs?"
] | [
false
] | See this video for an example: it just seems like wasted material to me, but they are engineers so they must have a good reason. | [
"Silicon crystals are produced in a process where they are continuously rotated and grow outward radially. It produces ingots like ",
"this",
", which are then sawed into the circular disks. As far as I know there is no process for growing similar quality crystals with a square cross section."
] | [
"This is indeed correct. Also, the silicon can be reused I believe so it's not like the extra goes to waste. In any case, it is purely because the processes used to make the 'pure' silicon do not produce square results."
] | [
"When you grow silicon crystals, they are grown on cylindrical pullers known as the Czochralski process. The cylinder is then cut into slices (like pepperoni from a sausage).",
"There are also efficiencies in the lithography tools for using circles rather than squares with edges. Think the way CDs or Vinyl Reco... |
[
"Why are humans good at dealing with ambiguity as opposed to say, a computer program?"
] | [
false
] | I think we could build a program that would understand ambiguity if we were to do something like build a database of every ambiguous statement we could think of, then define all possible meanings, then ask a program to choose the best based on the circumstances. Is that the same way we deal with ambiguity, just on a much more complex basis? Or is there something that makes us able to deal with it that no sort of computer logic will ever be able to match? | [
"Ambiguous reasoning can easily be programmed. Look into ",
"fuzzy logic",
". One commonly-used idea is to represent beliefs with probabilities. The field of machine learning, the most popular subfield of AI today, is based around this concept. ",
"As a simple example, every time you use a credit card a progr... | [
"it just matches what is written. ",
"it does a lot more than that, including deciphering what you ",
" to search for from what you ",
" search for"
] | [
"I think you're getting into trouble with \"ambiguity.\" If something is ambiguous it has multiple possible meanings, and you need some mechanism for sorting out which meaning(s) are required. To do this you'll need to bring in additional information not specified in the original ambiguous reference (if they tol... |
[
"Is the boundary between X-Ray radiation and Gamma Ray radiation a \"change of phase\" like with liquids and solids?"
] | [
false
] | null | [
"No. The electromagnetic spectrum is a continuum - our names for the different parts are just where we happen to place distinctions based on observed phenomena. For instance, \"visible light\" is called that because our eyes are able to respond to it. ",
"X-rays and gamma rays even have different distinctions ... | [
"Historically x-rays emerged from x-ray tubes and gamma rays from radiactive decay and the radiation from the tube had a lower energy.",
"Today this is not generally the case and you can have X-rays (from accelrators) with higher energy than low energy gamme rays. However, both are photons of a certain frequency.... | [
"No. There is just a continuum of frequencies, and we by convention decide to call electromagnetic waves with certain frequencies ",
" and others ",
" (and still others ",
" and ",
" and so on)."
] |
[
"Have we identified any objects at a fixed point in space that are not moving, relative to the universe?"
] | [
false
] | null | [
"Hi Indisputable1 thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the f... | [
"Please flair my query 'Astronomy'. Thanks. "
] | [
"Please re-read the instructions in the post above for how to add flair.",
"This is a common question. Try searching for something like \"universe stationary\". Unfortunately, because of the high volume, a lot of great questions and answers can get buried quite quickly. The searchbar can be a great way of explori... |
[
"If you become Paraplegic, would it make sense to amputate the limbs you have no feeling?"
] | [
false
] | null | [
"Why would you do that? Besides the risk of surgery, what if a repair treatment or assistive device is developed why would enable use of those limbs?"
] | [
"Aside from a medical reason would it be reasonable to remove unusable legs for example, if it offered increased mobility by way of weight reduction? The ballpark estimate seems to be roughly a third of body mass is the legs, so could that be an advantage to the person not having to carry that weight in/out of whee... | [
"Many paraplegics or quadraplegics retain at least some feeling in their legs, and amputating them, as mingy pointed out, completely removes the chance we can develop treatments for spinal cord injury in future.",
"The blood clot issues are not severe in healthy indivudals, and can be relatively simply combated i... |
[
"How can (relatively) slow evolving human immune systems keep up with very fast evolving bacteria?"
] | [
false
] | If the generation length ratio of bacteria to humans is something like 20 minutes:20 years, why can't bacteria just outrun the immune system recognition mechanisms, or destruction mechanisms? | [
"There are two reasons for this, related to the innate and adaptive immune system.",
"First of all, the innate immune system has, throughout evolution, been tailored to recognise invariant structures on the surface of bacteria. The reason these structures are invariant is because they are essential to the bacteri... | [
"It always amuses me that the tl;dr of immunology is basically brute forcing antigen recognition. "
] | [
"It's not brute forcing at all! It's totally spray and pray. We don't know what the enemy is going to look like next? Let's make antibodies for ALL THEM BITCHES POSSIBLE. Then when we find one that matches, we's gonna make a clone army! "
] |
[
"As space is a vacuum and laden with radiation bombardment, would a body on the moon decay, or last \"for ever\"?"
] | [
false
] | I mean, on a rather atmosphere-less body such as the moon or an asteroid, would they essentially be there for eternity (in regards to human timescale). I assume eventually they would freeze and break up due to either, a lot of little collisions over time, or a (few) big collision(s)... but would any anaerobic bacteria be able to decompose it at all? | [
"Aerobic bacteria still require air, they just don't require oxygen. In space, you would decay not from rotting but desiccation coupled with extreme temperature shifts. You'd dry out complete, and your remains would be in an environment that shifted between extremely hot and extremely cold. By extremely, I mean ex... | [
"Ah thank you. I forgot about the intense temperature shifts. I guess in my mind I was imagining the body was positioned in such a place say, as the northern or southern pole craters on the moon. The ones that have recently been found to hold a LOT of frozen water (as they never get sun light).",
"In the aforemen... | [
"Desecration happens regardless of exposure to sunlight. The lack of atmosphere is so... Vacuume-y that the liquid sucks right out of your body and.... Disperses into the lack of atmosphere. "
] |
[
"mirror puzzle"
] | [
false
] | Why is it that when you look into a mirror, right and left appear interchanged, but up and down do not? | [
"Feynman explains: ",
"http://www.youtube.com/watch?v=msN87y-iEx0"
] | [
"Mirrors really reflect ",
". You looking in the mirror is the same as looking at another person who is facing you; their right hand is opposite your left hand (and their left hand is opposite your right hand), but your head is opposite their head (and your feet are opposite their feet)."
] | [
"You looking in the mirror is the same as looking at another person who is facing you;",
"Not quite. Looking in the mirror is the same as looking at another person who is facing away from you, but has been \"turned inside-out\" (or frontside-back, to be more accurate).",
"their right hand is opposite your left... |
[
"Prompted by the question about stars on the front page today, I'm wondering, is it possible for there to be a solar system with only planets? I.e., all planets in the system orbit around a much larger planet at the center?"
] | [
false
] | null | [
"It's possible, but it does depend on what you mean by \"planet\" for the thing in the center. If a star forms with less than about 80 times the mass of Jupiter, it won't have enough pressure to ignite the fusion of hydrogen to helium in its core. This fusion is the source of almost all of the light emitted by star... | [
"Wouldn't that make the planets in the OPs question moons?"
] | [
"They're moons because they orbit a planet."
] |
[
"Why do we prefer muscles for vaccine injection?"
] | [
false
] | null | [
"Firstly, intramuscular and subcutaneous injections are not only easier on the patient but also on the trained professional. They're easier to administer and patients are often frightened of intravenous injections.",
"Secondly, antigen-presenting cells (e.g., dendritic cells) aren't just present in blood but are ... | [
"The muscles and/or subcutaneous fat can act as an easy \"deposition\" site for the injection. There is a lot of room to accept the injection bolus. Also, as opposed to direct injection into the blood stream, the immune reaction can be slower, more tempered, and cause fewer adverse reactions. Thirdly, it's easier t... | [
"To top off what everyone else has written The intramuscular route optimises the immunogenicity of the vaccine and minimises adverse reactions at the injection site. ",
"Injecting a vaccine into the layer of subcutaneous fat, where poor vascularity may result in slow mobilisation and processing of antigen, is a c... |
[
"If light moves at the same speed in all inertial reference frames, why does it get red/blue-shifted when you get closer to light speed?"
] | [
false
] | I was playing around with and , and both included redshift. If light always moves at c relative to you, wouldn't the color stay the same? | [
"The redshift/blueshift is a result of the perceived frequency of the light wave changing when switching inertial frames. How do you measure frequency? You count a certain number N of cycles of the wave and divide by the time T over which you observed those cycles.",
"Okay, now suppose an inertial observer is tra... | [
"Smart people,tell me if I'm right.",
"It's called The Doppler effect.Say you're moving to an object at a very fast speed,the wavelengths will compress,making the object appear more red.",
"The inverse is true,when you move away from an object at a very fast speed,the wavelengths will stretch,making the object ... | [
"Imagine that you're in a spaceship and traveling at half the speed of light (0.5c)",
"If you were to fire an object backwards at three quarters light speed and then look behind you, you'd see that object moving away from you at 0.75c. That's your relative velocity.",
"But an outside observer would see the obje... |
[
"If I bury my dog in just a burlap sack, why doesn't the ground sink in six months later, after she has decomposed?"
] | [
false
] | [deleted] | [
"It does, if the body is big enough. Google \"grave site ground settling\" for some info."
] | [
"Because they would decompose and become the soil, no?"
] | [
"because as the body decomposes and as invasive organisms digest it, their waste takes the place of the displaced soil. "
] |
[
"Can you explain me \"hyperbolic trigonometric functions\" and how can they be of use?"
] | [
false
] | null | [
"For example, the formula for the ",
"composition of velocities",
" in special relativity :",
"s = (u+v)/(1+(uv/c",
")",
"can be understood as a hyperbolic trigonometric ",
"identity",
" :",
"tanh(a+b)=(tanh(a)+tanh(b))/(1+tanh(a)tanh(b))"
] | [
"Hyperbolic trig functions are very much an analogue of the 'traditional' trig functions. If we look at the definition of the 2 normal trig functions:\n cos(x) = (e",
" + e",
")/2\n sin(x) = (e",
" - e",
")/2i, \nwhere i is a solution of y",
" + 1 = 0.\nWe can compare these to the hyperbolic trig function... | [
"Beyond looking at Euler's identity and solutions of ODEs there's other properties that the hyperbolic trigonometric functions have with the trigonometric functions.",
"Sinh is odd like sine (sinh(-x) = (e",
" - e",
" )/2 = -(e",
" - e",
" )/2 = -sinh(x)",
"And cosh is even like cosine (cosh(-x)=cosh(x)... |
[
"Why is a long chain hydrocarbon from crude oil less useful than a polymer thousands of carbons long?"
] | [
false
] | [deleted] | [
"long chain polymers, when manufactured, tend to have known structures and can be made in batches where those structures are relatively consistent.",
"long chain hydrocarbons are just single molecules that are long chains. Unlike polymers, they're not made up from a single small repeating unit, and when pulled f... | [
"Not all polymers are made from a single repeat unit, many have 2 or 3 monomers to make up the chain, allowing for very specific design of the polymer made. ",
"Also, on top of this, we can funtionalise the polymer chain to be better at the desired task, such as making it have lots of trifluoro-methane end units ... | [
"What's so useful about the heaviest fractions (longest chains) in crude oil? It's asphalt, not plastic."
] |
[
"Needing input on how to make this better/more accessible to people with little experience with Science."
] | [
false
] | null | [
"to be honest, It runs long. It's a little repetitious. I would try to trim about... 1 quarter to a third of the runtime out. Start with your conclusion. Then justify it. This is the best approach to public presentation I find. People get bogged down in detail and by the time you get to the conclusion, they're bore... | [
"Obviously there are spelling errors in a couple of places which need fixing, but anything else that could be done to make this more appealing or interesting?"
] | [
"Looks good! I think the one thing I'd do is add a little bit about how the rules also allow experts in different fields to trust information and work on their own area of expertise (Eg. if neuroscientists had different rules of proof to psychologists they couldn't use each other's work). "
] |
[
"Is \"String Theory\" even a theory? Should it better be called \"String Philosophy\"?"
] | [
false
] | This is not trolling, but a serious question. Does it have any experimental predictions that can be used to verify / falsify it? My understanding is that with the landscape scenario there are at least 10 possible vacua (initial conditions) for potential universes and the anthropic principle is used to explain ours. Is this really a physical theory, or more a philosophical theory since it doesn't appear testable? | [
"It's absolutely a theory. ",
"It's not impossible to test ",
". It's just impossible with our current technology. ",
"It would be testable directly if we could build a particle accelerator about 10",
" times more powerful than the LHC. Such an accelerator would have to be about the size of the galaxy."... | [
"String theory would be better described as a general mathematical approach. One can talk about a string theory in the sense that one can talk about a quantum field theory, and in my limited understanding a string theory is somewhat of a natural generalization of a quantum field theory.",
"You could make the same... | [
"Pretty much any collider can get particles moving so fast that the difference between them is negligible if you just compare speeds alone, as they can only asymptotically approach the speed of light.",
"There is no limit on the amount of ",
" a particle could have though, and this is the critical number for th... |
[
"\"earth/ground\" node in electrical circuits, how does it work?"
] | [
false
] | I can’t get my head around earth/ground in electrical circuits, from what I understand the Earth itself is a reservoir of free electrons and it was used as a return pathway in single phase power transmission systems back in the days, but how? And from where these electrons come from? The earth consists of rocks and dirt which they have a very high resistance to the flow of electrons, how can it be treated as a current carrier? The “ground node” as we refer to it is just a metallic rod/mesh buried in the ground | [
"\"Reservoir of free electrons\" is probably a misnomer. Circuits are based on electrons flowing, not free charges. Separated charges are extremely uncommon.",
"You are also correct that the ground is resistive: typically 10 - 1000 ohm*m, compared with 10",
" ohm-meters that is typical for metals.",
"However,... | [
"I'm not perfectly certain, to be honest. It takes at least ",
"20 ms",
" for any electrical signal to propagate through the earth, so in many situations where you need a large ground, including radio waves, lightning strikes, and power surges, you can't treat the earth as a static component - it will take a wh... | [
"Circuit ground is a ",
" convenient approximation, much like the old joke about modeling a cow like a sphere or cylinder for heat transfer analysis. The reality is that there isn't any such thing as zero potential. Voltage is a statement about the difference in electric potential between different places, equa... |
[
"Do arterial blockages get diagnosed regularly before symptoms?"
] | [
false
] | I realise it’s probably a selection bias at play but I seem to regularly hear stories where someone who was otherwise healthy and led a healthy lifestyle dropping dead from a heart attack with no prior symptoms. Are there non Invasive diagnostic tools available that can pick up any issues with a regular GP check up or do you generally just go to hospital after you have symptoms? | [
"Exercise stress testing or cardiac CT angiogram can be used as screening tools to help prevent a potential myocardial infarction. Echocardiograms can evaluate for valvular heart disease. \nRisk factor modifications controlling BP, diet exercise, keeping cholesterol in check are preventative medicine strategies to ... | [
"We don't do exercise stress testing or CT scans on asymptomatic people to prevent MI. The obstruction has to be pretty advanced anyway for exercise stress testing to show restricted flow."
] | [
"No. There are different types of arterial blockages but I'll talk about 3 common ones: coronary artery disease, carotid artery disease, and peripheral arterial disease.",
"For coronary artery disease, this is when there is atherosclerotic blockage in your coronary arteries, or the arteries that directly supply y... |
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