title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Does produce absorb pesticides directly or though water?"
] | [
false
] | So eating pesticides isn't good. I wash my stuff in baking soda usually to try to get off what I can. I'm curious however if plants absorb pesticides directly into their flesh? For example avocado... can you spray avocados with pesticides all you want and it will be safe to eat because you are removing the thick external cover? Or will the pesticide leach into the water, and then be absorbed by the plant, then eaten by you? Or does it perhaps get absorbed directly through the skin? Just curious! | [
"Most commonly used substances (in North America and most of the EU) are removed well enough by just water washing",
"This is not true. Washing will be ineffective against a large array of hydrophobic pesticides, or those that absorb deeply.",
"they're present in levels far lower than what is required to show ... | [
"Most commonly used substances (in North America and most of the EU) are removed well enough by just water washing",
"This is not true. Washing will be ineffective against a large array of hydrophobic pesticides, or those that absorb deeply.",
"they're present in levels far lower than what is required to show ... | [
"Thanks a lot for the info!"
] |
[
"How do astronomers share coordinates with each other?"
] | [
false
] | Let's say an astronomer notices something worth studying out there.... How do they tell other astronomers around the world, or just record exactly where they are looking at? For instance for coordinates on Earth they'd give a lat/long and that would always be the same place. But in space, everything is in motion and therefore relative to the observer. The earth is moving in space, and rotating as is whatever object is being studied. So on any given day, or even time, the object being studying is not going to be in the same 'relative' space as it was yesterday, etc.... So how are coordinates marked for collaboration or future study? | [
"The sky has a similar set of coordinates as the Earth - in fact, the coordinates have the same names: latitude and longitudes. You’re correct in that the sky appears to move above us as the Earth rotates, but we astronomers have solved this by specifying a point on the sky that we define as always having coordinat... | [
"We use something called ephimerides, which describe how much an object moves in longitude and latitude (Right Ascension and Declination) per day etc. In other words, they describe the trajectory of a moving celestial object. The vast majority of celestial objects don’t move appreciably on the sky from one year to ... | [
"thanks, very clear explanation... but followup ",
"The object we are studying might not move in the same repeatable orbitable pattern around our (0,0)... like say a comet or asteroid that is moving in a straight line out of any given orbit. So regardless of our \"0,0\" point - that will constantly be moving .... |
[
"I have a few questions about embryonic development and nuclear transfer in cloning."
] | [
false
] | So, I know in nuclear transfer with an embryonic cell, the blastomeres of an embryo are separated and fused with enucleated eggs. These in turn are grown into embryos and implanted into surrogates. Does that mean the blastomeres are essentially just nuclei? I'm not sure what they consist of. I know the alternative is somatic cell nuclear transfer, but in that case it's just the nucleus of the cell being fused with the egg. Doesn't a blastomere have more content than just a nucleus? Also, at what point in development do embryonic cells differentiate? And are they innately programmed to differentiate a certain way or is that not determined until it happens? I know in embryo splitting the blastomeres have to be undifferentiated, but when those become their own embryos and cells start to specialize, would it matter what that blastomere was supposed to specialize as originally? Can it change that specialization if necessary now that it's part of a new embryo? I'm pretty new to this, so I'm not sure if these questions even make sense. But thanks to anyone who can help! | [
"Depends on what organism you are talking about (differentiation). I am assuming you are referring to mammals. The very first proto-differentiation would be the determination of the three germ layers (Ecto-, Endo- and mesoderm) which occurs ~3 weeks after fertilisation. ",
"Did you mean a more specific kind of di... | [
"Blastomeres have undergone no differentiation events (As far as I know. Xenopus eggs undergo something called cortical rotation after fertilisation. It essentially creates a molecular gradient within the egg and specifies the formation/location of the inductive signal producing Spemanns Organiser). So blastomeric ... | [
"A blastomere is just a regular cell, morphologically as far as I am aware. I imagine in cloning they would specifically microinject the nucleus from the blastomere into the egg, or they would zap both with a jolt of electricity to fuse their membranes. The blastomere will be much smaller (~8 times in fact!) than t... |
[
"Can someone explain the difference between particles and virtual particles?"
] | [
false
] | Are they literally the same thing? If so, why are they virtual? Or is there some sort of meaningful difference between them? Or are they just never actually 'observed' quantum particles? That don't get a chance to define themselves? I've been confused on this. Side question, what do we mean when we say 'observe' in quantum mechanics. Is that really the same kind of observation we think of when we observe something on our own scale? How does a scientist actually 'observe' a particle, like I would 'observe' a cat. Am I asking the wrong questions? | [
"Virtual particles are created by vacuum fluctuations.",
"This isn't really true. Virtual particles are not real. Maybe we use virtual particles to represent quantum fluctuation of the vacuum, but you can not create a virtual particle, they are not real things."
] | [
"Virtual particles are NOT REAL THINGS. They do not exist. They are calculational tools. They are things we use to help us break down the complicated interactions of fields into just the most important parts. That way we can compute only the important parts and get very close to the right answer.",
"You can not o... | [
"Well yes, but that's really about how we define real. For example is an electromagnetic field real or is it just how we describe the electromagnetic interaction by Maxwell's equations? Whether something is real or just a smart theoretical construct can be difficult to say. I find discussions like this insanely fas... |
[
"What happens to the ectrons and protons in a neutron star?"
] | [
false
] | null | [
"The electrons merge with the protons to form neutrons, emitting a neutrino. This is known as electron capture, and also happens in less exciting scenarios like the decay of potassium-40 in bananas."
] | [
"That's interesting. Do they emit enough neutrinos that having a banana at one of those subterranean neutrino labs could skew results?"
] | [
"I don't think so. Much more neutrino flux from the sun."
] |
[
"How are the amount of calories in food determined?"
] | [
false
] | I assume they do a breakdown of the ingredients and go by how many calories are known to be in that ingredient, but how was it initially determined? | [
"An analysis of the item will determine the amounts of protein, carbohydrates, (both about 4 calories per gram) and fat (about 9 calories per gram.) If alcohol is present, that comes in at about 7 calories per gram. ",
"The rest is just math. "
] | [
"It must be difficult to use this method for soup."
] | [
"It must be difficult to use this method for soup."
] |
[
"How do GPS satellites cope with the millions of vehicles requesting their locations at once?"
] | [
false
] | I presume there are loads of GPS satellites that triangulate the position of vehicles with satnavs etc. but are there computers onboard these satellites and how do they relay all that information at once to the right vehicle? | [
"They don't. They simply beam their signal and the client does all the work "
] | [
"The traffic is not peer to peer.\nVery much simplified it works like this:\nEssentially the satellites have super accurate clocks. They broadcast the current time and their ID with their radio. Like radio everyone with a receiver can listen to them. From ID and time you can calculate how far away they are. \n(Curr... | [
"No, geometry is why you need signal from a few satellites. 1 satellite tells you that you're somewhere on a given circle (technically a sphere but there's a circle where that intersects with the Earth's surface), 2 narrows it down to two points (the circles from the two satellites intersect at 2 points), and 3 giv... |
[
"If sodium nitrate is known to cause DNA damage then why does everyone think it's OK for it to be used as a preservative in all our meat products?Are there not alternative preservatives?"
] | [
false
] | null | [
"It's a risk/reward scenario. Nitrates can potentially increase the risk of cancer - the degree to which the risk increases is not firmly known. However, nitrates are ",
" effective at inhibiting pathogen growth in high-pH foods like meat, especially considering their cost and ease of use. Much like sulfites, whi... | [
"According to the ",
"IARC",
":",
"Ingested nitrate or nitrite under conditions that result in endogenous nitrosation is ",
"(",
"source pdf",
" - lots of evidence there.)\ni.e. it probably can cause cancer when ingested with amino acids e.g. from meat. On the other hand alcohol is a ",
" proven carci... | [
"So is that information bullshit? I know it says a small percentage is converted but could it be significantly harmful to someone that includes meat in every meal?"
] |
[
"Do our brains create consciousness, or receive it? What's the hard evidence for each side, if any at all?"
] | [
false
] | null | [
"This would be a good question for ",
"/r/philosophy",
". If you sort by TOP it's probably been addressed"
] | [
"The answer depends. How you define \"consciousness\" matters. If you include some kind of metaphysical, unscientific \"soul\" or \"will\" or something like that, then the answer to your question can only be metaphysical and unscientific, so you must be very careful and precise with your definitions to keep the a... | [
"If it's an emergent property, then it arises (i.e. it is generated/created) dynamically and is not merely some conserved thing which is received.",
"Either way I suspect that consciousness isn't simply a single property, but a complex collection of many coexisting properties."
] |
[
"Would deforming an open soft drink bottle to remove air space, before recapping, stop/slow it from going flat?"
] | [
false
] | I'm thinking the co2 wants to leech into the air space, if there is no air the co2 can't easily leave the soft drink? | [
"MAJOR EDIT 2! ",
"The great thing about Science, is that we can be wrong. Because I am very lazy, I did not read this carefully enough before posting. ",
"When, in the past, people have asked me this, they shown me deformed bottles, squeezed such that there is only about as much head space as there is when the... | [
"No. In fact, quite the opposite. The bubbles are carbon dioxide gasses held in suspension in the soda by high pressures. As the pressure increases, more gas dissolves. Squeezing then capping the bottle puts negative pressure on the liquid, causing the gas to fall out of suspension faster. "
] | [
"Fresh carbonated soda has about 4x its liquid volume in CO2, at about 25-30PSI (varies by temp) above standard air pressure in the headroom. The headroom is only necessary to prevent foaming over when it bubbles up when opened.",
"Any time it's opened, however much headroom is there immediately drops to the pre... |
[
"Is there a strong likelihood that we will all die in the near future?"
] | [
false
] | [deleted] | [
"Don't listen to anyone here, it's all speculation, we have no idea."
] | [
"Hmm a list: (Mostly questions, little answers.)",
"Greenhouse effect, main question is if it: 1) causes other biosphere breakdown 2) could it cause an iceage 3) where does land value in terms of food production decrease/increase? ",
" everything diplomatically/politically works out, and the overal value stays ... | [
"Thanks for that. "
] |
[
"Effect of house plants on air quality?"
] | [
false
] | I know we recently had a post about how many plants it would take to keep a person who alive, but does anyone know of any studies that show that average quantities of house plants have any measurable effect on home air quality? | [
"NASA studied this because they are interested of cleaning air in space stations. The answer is yes, they do improve air quality. ",
"Here is a list of plants and what they clean: ",
"http://www.colostate.edu/Depts/CoopExt/4DMG/Plants/clean.htm",
"Wolverton et al. ",
"\n",
"http://ntrs.nasa.gov/archive/na... | [
"I found a physorg article citing another study backing this up as well. ",
"news article",
"\n",
"source"
] | [
"They tried an experiment with this as a part with the \"biosphere\" in AZ. They needed to fudge around a bit to keep it going."
] |
[
"Why does an infinite plane of charge have a constant Electrical Field?"
] | [
false
] | I'm learning electrostatics in Advanced Physics right now and was taught that the electrical force exerted on an object at any location in respect to an plane of charge is a constant, 4 pi k Q, regardless of distance. Why is this? On that note why can't you use this distance-ignoring factor and affect things faster than the speed of light? Does that make sense? After his lectures the vocabulary fades from memory a bit. Edit: All sorted out! | [
"I'm learning electrostatics in Advanced Physics right now and was taught that the electrical force exerted on an object at any location in respect to a plane of charge is a constant, 4 pi k Q, regardless of distance. Why is this?",
"This applies to an ",
" plane. For anything else, it's an approximation. For a... | [
"Think about the field lines. Where else are they going to go?"
] | [
"On that note why can't you use this distance-ignoring factor and affect things faster than the speed of light?",
"Well, you're learning electrostatics. That means that all the formulas for electric fields that you're using are technically only true when the objects are not moving, and were not moving in the past... |
[
"Do these up and down changes in temperature effect mosquitoes and other bugs negatively or positively?"
] | [
false
] | null | [
"What temperature changes do you mean?"
] | [
"Air temperature."
] | [
"Daily? Seasonal?"
] |
[
"What tactics were used by humans to hunt mammoths?"
] | [
false
] | I hope this question isn't too speculative for . A confirms spears were used against Mammoths which got me wondering what were the tactics used during the hunt? How did humans take down such large animals? *How many humans had to be involved? *How many spears were needed to take down a Mammoth? *Were any other tools used, such a rope to tie down the animal? *Did hunters spear and let the animal bleed out? *What do we know based on current hunting techniques? | [
"Unfortunately, you're not going to find much on this topic aside from pure speculation. The evidence that humans actually even hunted mammoths isn't strong enough to be beyond question. What one archaeologist interprets as butchering marks on bones might be interpreted by another archaeologist as marks from tram... | [
"What I know, from psychology and etology studies, is that humans tried to engage big animals, such as mammoths, when one of them were isolated from the group. They would have one put one human to distract it (probably a skinny, fast one), while the others, stronger and bigger, would throw spears at them and attack... | [
"Historically Native Americans would use the skins of other animals as camouflage to get close to buffalo, they would then all attack the bufflao by throwing spears and shooting arrows at it or chasing it off a cliff. It is likely that early humans used similar tactics to close the gap between them and the mammoth.... |
[
"If the testicles are an external organ for sperm to survive (as they die in normal body temperatures), how do they survive once they are in the female body?"
] | [
false
] | null | [
"Sperm, like any other cells, have their optimal temperature in which they perform their task they are supposed to do. For spermatogenesis, the optimal temperature is 34ºC (that's why the testicles are a bit outside of the body), but for the end form (sperm), they move normally in higher body temperatures. \nWhat k... | [
"Yes! One interesting discovery is the idea that all mitochondria were once outside invaders that relied eventually ended up relying on its host to survive. The host kept the mitochondria around because of they produced energy. This theory of ",
"endosymbiosis",
" was proposed by ",
"Lynn Margulis",
", an e... | [
"plus sperm mitochondria are spent by the time they inseminate the egg resulting in everyone's mitochondria being from their mother. This organelle has it's own DNA, mDNA, which has led to interesting discoveries."
] |
[
"How do you form long term memories? How can you form long term memories while studying?"
] | [
false
] | null | [
"The general consensus is that a memory causes connections between neurons in the medial temporal lobe of the brain to be altered more or less in real time. This process has been studied particularly well in the CA1 region of the hippocampus - a medial temporal lobe structure. The neurons there always have some lev... | [
"Thank you, great answer!"
] | [
"From a psychology point of view, long term memory is the consolidation of memory from short term or working memory into a long term storage.",
"There are a few ways we do this. The most common is rehearsal. You simply rehearse whatever you want to memorize over and over, and this translates it into long term mem... |
[
"Question about sedation dentistry"
] | [
false
] | null | [
"Hey there,\nIts normal to have a little pre sedation if you need it, and the dose and advice you were given is pretty common too, so dont worry about that being unusual - its not.",
"The chances of you waking up are absolutely incredibly minuscule. Seriously, usually its the opposite and the anesthetist is just ... | [
"The chances of you waking up are absolutely incredibly minuscule. Seriously, usually its the opposite and the anesthetist is just sitting around impatiently for you to wake up afterwards.",
"I can't emphasise this enough. Anaesthetists are incredibly well trained to make sure you're sedated enough. They monitor ... | [
"This is not my area, but your post is five hours old and you need some kind of reassurance. I apologize to the mods for the anecdote.",
"When I had my wisdom teeth taken out, the surgeon realized that they were going to be very difficult to remove. They prescribed a small amount of valium to be taken before su... |
[
"How do the waveforms generated by synthesizers (square, sine, triangle, etc.) compare to the waveforms of \"natural\" sounds and those of \"real\" instruments?"
] | [
false
] | I've been wondering this for awhile, and didn't have much luck with google. Some of the waves produced by synthesizers clearly do not occur in nature (I don't think anything natural sounds like a sawtooth wave) but what about, I don't know, sine waves? Every time I've seen an "example" sound wave it's looked like a sine wave, but then again it could be some other round-topped wave. Or, if not, what are the sound waves we hear from guitars, violins, or bird songs? Also, one secondary question: How is the waveform of guitars affected by distortion? Since modern-day distortion is usually extremely controlled and well-shaped, I'm assuming there's a bit more going on than just "making it louder until it distorts." I once heard that fuzz pedals start to "bend" the waveform of the guitar towards being a square wave as they're turned up, don't know if that's true or not, though. EDIT: Yeah, that is how fuzz pedals work. | [
"You're asking a few different questions here.",
"If you think of a wave as energy vibrating back and forth you have a constant compression/rarefaction cycle of the movement of the wave. A 'sine' wave is simply a mathematical construct to describe the position of the wave anywhere in this cycle of going back and ... | [
"The waveforms commonly used in synthesizers weren't initially selected because of their musical quality. There were used because the circuitry to create them already existed. Sawtooth waves were used in televeision sets to sweep the electron beam across the front of the CRT and then rapidly return it to draw the n... | [
"The noise comes from when you clip off the peaks of the wave; if you were to zoom in very far on the wave form every ripple you see outside of a smooth line is essentially a new frequency being introduced into the complex waveform."
] |
[
"AskScience AMA Series: We are experts looking at connections between the gut microbiome and mental health. AUA!"
] | [
false
] | Is there a connection between what you eat and how you feel? A large body of research has demonstrated a strong association between the gut microbiome and mental health. Microbes have been associated with neurological disorders ranging from degenerative diseases (such as Alzheimer's, Parkinson's, ALS and dementia) to mental health disorders (like depression and anxiety) that are becoming all-too-prevalent in today's society. However, there is still much that we don't understand about how these relationships are established or maintained. Join us today at 2 PM ET (19 UT) for a discussion with experts on what is being called the "psychobiome", organized by the American Society for Microbiology (ASM). We'll discuss what we know about the relationships between microbes and hosts, how these relationships impact our behavior, moods and mental capacity, and what each of us can do to strengthen the health of our microbiomes, and, ultimately, improve our mental health. With us today are: Links: EDIT: We are done for the day, thank you all so much for your interest in our work! | [
"What effect do SSRI/SNRI medications have on the microbiome? How does the microbiome effect serotonin and other neurochemical production/uptake? Are there any correlations between inflammation and microbiome diversity? As somebody with Crohn's disease and depression I'm always desperate to understand the connectio... | [
"My colleagues will reply after 2pm, but I suspect there will be lots of questions, so I will take some now. ",
"The answer is studies have not been done (but are badly needed) on the effect of these medications on the microbiome, nor on how the microbiome affects drug uptake and efficacy. I suspect drug companie... | [
"What sort of foods tend to have the strongest positive and negative effect on the gut microbiome, and in turn, mental health?",
"Slight tangent from that, is there a particular regional or cultural diet you've found that has a better overall impact on these two? Would be interesting to see if a particular area o... |
[
"Why is the surgery room so cold? Is this so only to prevent surgeons and nurses from sweating too much, or is there also a reason for hygiene?"
] | [
false
] | null | [
"because the surgeons wear gowns, gloves, masks, and hats. Sometimes they have lead aprons on their body and neck to protect against radiation from x-rays. And there are bright, hot lights shining down on the patient that shine on the surgeons as well. These make the surgeons heat up and become uncomfortable."
] | [
"This. Also, a lot of the equipment used in operating rooms can be temperature sensitive and can get pretty hot from running. So it’s also to maintain temperature in electronics."
] | [
"Our operating room is set to between 68-72F primarily for staff comfort. Operating in a hot theatre is ",
" uncomfortable. Wearing lead vests and multiple levels of gowns and face protection gets hot very quickly. The last thing you want in an OR is surgeons sweating into the surgical site or passing out.",
"W... |
[
"Are there any other ways to relate Newtonian physics to Coulomb's laws, specifically Coulomb's constant, aside from special relativity?"
] | [
false
] | Even if just in theory, quantum or otherwise? | [
"special relativity does not depend on G (if by G you mean the gravitational constant). General relativity does say that space-time curvature is related to the stress-energy tensor through the gravitational constant and some other factors. But special relativity is constructed in 'flat' Minkowski space-time so ther... | [
"If I'm to understand you correctly, you're saying the less mass something has, the more inherent it's velocity is to C? ",
"It's actually a binary thing. 0 mass implies velocity must equal c, no more no less, from any inertial reference frame. Non-zero mass implies speed must strictly be less than c from any ine... | [
"I'm not sure what you mean by connecting Newtonian Physics to Coulomb's law. What variable or constant do you wish to relate to Coulomb's constant?"
] |
[
"If the voltage id high enough, would electricity be able to arc in space?"
] | [
false
] | null | [
"What we see as an arc is the effect of molecules in the air being excited by the impact of electrons that are accelerated by the voltage. These excited molecules then fall back to a lower energy state and emit a photon. This is the light we see when there's an electric arc.",
"In space, without air, there's noth... | [
"Of course, why wouldn't it?\nWith vacuum all around you, you'd be the best conductor around."
] | [
"Once electrons escape the confines of the metal electrode, they just follow electric field lines. Between two charged parallel plates, the electric field is more or less constant and pointing in the direction of the negative plate, so electrons will be moving against the field lines (and accelerating according to ... |
[
"ARC - A nuclear fusion reactor from MIT smaller and cheaper than ITER - a year has passed and no one talk about it. Why?"
] | [
false
] | edit: The name of the reactor designed by MIT is SPARC. Video: | [
"The history of fusion, like it or not, are accounts of people saying \"my idea will work out great, I'm sure of it, if only I get enough money to scale it up!\" So far, whenever the money has been provided, it turns out that scaling it up is harder than they realized and creates new difficulties, and sometimes mak... | [
"You can make a fusion reactor on your desktop. Fusion reactions are pretty easy to initiate, you just need to slam Deuterium and/or Tritium together at high speeds. But, to get a self-sustaining fusion reaction you need to confine a fusion plasma for long enough and at high enough densities and temperatures for th... | [
"But seeing how ITER is being continuously delayed, wouldn't be better if they could make smaller reactor in less time ",
"no you completely misunderstand the matter. we have been building small factors for decades! it's not better. we now want to build bigger. that's the whole point. yes it takes a lot of time ... |
[
"Has there ever been a pair of contradicting unsolved maths problems?"
] | [
false
] | i.e. A pair of unsolved conjectures such that proving one of them would automatically disprove the other. | [
"Yes. There are two conjectures by the famous mathematician(s) Hardy and Littlewood that contradict each other. ",
"The first is the ",
". This is a generalization of the Twin Prime Conjecture. The Twin Prime Conjecture states that there are infinitely many prime numbers p so that p+2 is also prime, ie there ar... | [
"/u/functor7",
"answer",
"Every even integer greater than 2 can be expressed as the sum of two primes.",
"Not every even integer greater than 2 can be expressed as the sum of two primes.",
"Point is, it's easy to construct one given the other. :-)"
] | [
"No, they could both be false. The fact that both conjectures are inconsistent with each other only implies that they can't both be true."
] |
[
"Redshift and Conservation of Energy of the Photon"
] | [
false
] | So it's my understanding that light traveling from distant galaxies has its wavelength shifted due to the expansion of the universe. The energy of the photons is inversely proportional to the wavelength. So, if the photon wavelength increases, some of that photon energy is lost as it travels through the vacuum of space. Where does that energy go? | [
"From the reference frame of the star, the wavelength of the photon doesn't change at all (at least assuming constant velocity, which isn't entirely accurate because of \"Dark Energy\"), and from the reference frame of a stationary observer it also doesn't change. So the answer is that the energy doesn't go anywher... | [
"I ",
"asked",
" the same question. ",
"The answer seemed to be along the lines of conservation of energy only applies in a closed system, and the expanding universe isn't considered a closed system."
] | [
"In an expanding universe you don't have global conservation of energy."
] |
[
"When cold, why does covering oneself in a blanket produce the feeling of warmth instantly and not gradually?"
] | [
false
] | The title says it all. Shouldn't the body temperature increase gradually? | [
"It changes immediately because the feeling of cold is due to the rate of heat loss. Your body is still generating lots of heat you are just losing it too quickly to stay warm. A blanket immediately changes that dynamic and begin feeling warm almost right away. That isn't going to be the case if you are hypotherm... | [
"Are you saying that we sense the rate of heat change and not the heat itself? That claim doesn't match reality. ",
"Or is it a combination of the two?"
] | [
"No that isn't what I was saying. I was saying that your body is trying to keep up and can't so you feel cold. The cold you feel is generally due to your surface heat. "
] |
[
"What actually is balding?"
] | [
false
] | What is actually going on when hairlines start to recede and why do Humans bald in the first place? Do other creatures bald? | [
"Humans go bald when their hair follicles revert back to vellus hair, which is the hair that first grows on newborns and is also known as peach fuzz. Hair has three different stages, anagen (growth), catagen (when the follicle stops growing and begins to get pushed up) and telogen (resting phase). Balding occurs wh... | [
"Makes sense, but why does it always start at the front and move its way back on men, and seem to thin out all over on women? "
] | [
"I don't know if that is an accurate statement. Plenty on men develop a bald spot on the back of their head. I have also seen some men who the top of their head just gradually thins out relatively evenly. "
] |
[
"Hey science reddit! I know most of you are buy answering the elementary school class, but: What is the practicality of using piezoelectric generators in the infrastructure to offset electrical generation costs?"
] | [
false
] | null | [
"I work with piezoelectric transducers. The amount of power that they generate is incredibly small."
] | [
"It's been tried for flooring, but the cost offset of the piezos is enough to offset electrical savings, in most cases. This hasn't stopped the development of a number of schemes that would integrate piezos into structures, but I haven't seen anything built beyond concept stages. "
] | [
"Whoah. That's an idea I've never heard of before. Now, I'm not a civil engineer, but I don't think it would be terribly practical to replace say, even just flooring with these things. Materials used in piezo are very different from those we want to use in construction. "
] |
[
"Will there ever be a new eye color in humans?"
] | [
false
] | I know that at one point all humans had brown eyes, and blue and green popped up somewhere along the way as random mutations. How possible would it be for another similar mutation to take place again? What would be the most probable/realistic eye color? My guess was yellow, but I have no scientific evidence or reason to believe so. | [
"Here's a pretty handy ",
"chart",
" for the cause of various eye colours.",
"EDIT: Apart from the current causes, it would be unlikely different kind of pigment is produced to generate newer eye colours, unless we dabble in a little bit of genetic modification.",
"Also fun fact, Elizabeth Taylor had violet... | [
"I'm not an expert, but I've seen eye colours that came pretty close to being yellow. At the end of the day, colour is a subjective perception, perhaps yellow is poorly recognised because it may not come out too strongly."
] | [
"Wow.",
"If I may ask, is your vision normal?"
] |
[
"I still don't understand why viruses aren't considered 'alive'."
] | [
false
] | Or are they? I've heard different things. | [
"There is not, at present, any ",
" evidence that \"alive\" and \"not alive\" are physically meaningful categories.",
"Look at it this way. Say I gave you a box of old books, and asked you to sort them into two piles: those that are \"cool\" and those that are \"uncool.\" Now, you're not just putting books in p... | [
"The distinction between \"life\" and \"non-life\" at the fine level you're talking about isn't \"fuzzy\", as some people have said, rather it's ",
"."
] | [
"You can say that they're viruses and prions, and that different people put them in different boxes.",
"To steal RRC's metaphor, you're asking \"Is ",
" definitively cool, definitely uncool, or definitively in-between-cool?\""
] |
[
"Does every solar system have an Oort cloud?"
] | [
false
] | null | [
"Well, given that we barely know anything about our own Oort cloud given how diffuse, distant, and dim it is, it's going to be a very long time before we can say anything definitive about other planetary systems.",
"However, it's extremely likely that any system that forms planets will have some leftover debris. ... | [
"What's known about Oort cloud basically amounts to \"wow, comets come through the solar system on all sorts of crazy trajectories, from basically every direction. Therefore, there must be a relatively large population of comet-like bodies in the outer solar system, more-or-less evenly distributed in every directio... | [
"Correct. The Oort cloud isn't something well bordered. There is no exact inner and outer limit. It is basically just scattered debris."
] |
[
"Why is it that imaginary numbers show up frequently in electronic physics and not in particle physics?"
] | [
false
] | This came up in my calculus class today and my teacher had no clue. I figured might know. edit: By the responses I have gotten, I see that my calculus teacher was wrong. | [
"Imaginary numbers lie at the heart of the mathematical formalism of particle physics. The question doesn't have a good answer because its premise is false. What you predict in particle physics are probability amplitudes of a state being observed, which when multiplied by their conjugate give you the square of the ... | [
"Imaginary numbers do in fact show up quite frequently in particle physics (and indeed anything related to quantum mechanics). For example, the ",
"Schrödinger equation",
" contains the imaginary number i in its time-dependent formulation.",
"By \"particle physics\" did you mean something other than quantum ... | [
"They also show up in the Dirac equation, spinors, and lots of Lie algebra stuff. "
] |
[
"Yet another relativity question"
] | [
false
] | I understand how your relative speed affects your observation of time. i.e. if you look at a clump of photons at speed A then those photons will hit your eyes at a particular rate, if you speed away from that clump (at speed A + nearly c) then those photons will hit your eyes at a much slower rate. The jump that I don't get is where people say "and the same is for the passage of time". I don't understand how this phenomenon affects clocks travelling at different speeds, how does your speed relative to light effect the mechanics of a clock? How does going on a space cruise effect aging? I just don't understand this. I've googled it and any explanation that I can understand seems to skip over this step. Can anyone help? | [
"if you look at a clump of photons at speed A ",
"Photons always ",
" travel ac ",
". You're confusing time dilation with the Doppler effect. Consider what would happen if you moved ",
" the photons. By your logic, time should speed up. This is now how time dilation works; an observer with a velocity relati... | [
"One of Einstein's postulates were that the speed of light is always constant no matter which reference frame the observer is in (so no matter what speed objects are moving relative to the observer). So a constant speed of electromagnetic waves in a vacuum is necessary for all the time dilation business to be true,... | [
"Layman here but here is my take on it. I welcome corrections, \nof course.",
"The first rule is the speed of light is constant in all reference\nframes. Anytime the speed of light is measured, the same\nspeed is always the result.",
"Imagine a pulse of light bouncing between two mirrors, one on\nthe floor and ... |
[
"Why do your clothes get unwrinkled in steam but your hair gets curly?"
] | [
false
] | I'm guessing it has something to do disulfide bonds and water molecules but that is as far as I got. | [
"You're on the right track.",
"What happens is that the amount of available water effects the interstrand hydrogen bonding, which is largely responsible for the wrinkles in clothes. The water binds to the cellulose (in cotton of course) or polymer chains (in synthetics) and breaks up the hydrogen bonds. ",
"... | [
"Amazing! Thanks!"
] | [
"I just used \"The curliness of your hair is determined by the disulfide bonds in the structure\" as a fb update... what's wrong with me?"
] |
[
"What causes us to twitch and suddenly wake out of sleep?"
] | [
false
] | Does anyone know what causes us to suddenly twitch and move violently out of sleep? This happens to me most frequently during the early stages of sleep, and also most always when i'm falling asleep after MDMA use. I realize that might have two different answers, but i'm curious as to what they are. | [
"These are called \"hypnic jerks\" and are a form of myclonus. You mention MDMA. Drugs sold as MDMA usually have some affect on dopamine and seratonin, and these are thought to be involved in some hypnic jerks."
] | [
"I thought it was \"myoclonic jerk\""
] | [
"Well that about covers it then!",
"That's a brief intro to what it ",
" be. ",
"Given that you spend about a third of your life asleep, the dynamics of sleep should interest you. And just because your conscious mind is not driving the situation, you shouldn't be fooled into thinking that there's not a lot go... |
[
"Dark-matter, expansion of the universe, Wimp and quantum mechanics"
] | [
false
] | So, I was reading this: From a earlier post today. My question is way off topic (in my eyes). With "80 per cent of the universe's matter must be dark" and "These WIMPs collide in space, annihilating and decaying into ordinary particles, including electrons and their antimatter counterparts, positrons." Does this imply that, in fact, the "Dark Universe" is shirking, to expand ours? And that "maybe" quantum mechanics is "part" of the interplay of the particles from "one" part of this "Dark Universe" (with our universe)? Like the "spooky action" called Quantum entanglement. Or am I being a Noob on my first post here? | [
"It's also important to stress that the notion that dark matter interacts via the weak force (hence, WIMPs) is a proposal that has by no means been confirmed. We know the vast majority dark matter doesn't interact via the strong or electromagnetic forces, and it is consistent with what we know that dark matter cou... | [
"First off, dark matter is in our universe, and isn't separated in any special way - it's actually mixed in quite happily with normal matter most of the time. Saying the universe is 80% DM, 20% normal matter is just like a cake which has 250g flour, 250g sugar and 3 eggs - they're all in there, but they're mixed to... | [
"Indeed. It's not even certain that dark matter is a single kind of thing at all, it could be a combination of different particles. WIMPs are favored because they can be detected, even if it is difficult to do so. If dark matter isn't at least weakly interactive, we may not be able to ever directly detect it."
] |
[
"Why are cells (e.g brain cells) irreparably damaged so quickly when deprived of oxygen?"
] | [
false
] | null | [
"One of the things the other commenter didn’t mention is alternative metabolic pathways. When there’s no oxygen, your body will use other stuff to make energy, and that stuff can create byproducts that rapidly kill the cell. If a little gets created during normal function, the cell can clean it up. But no oxygen, n... | [
"A tourniquet stops the major flow of blood when there is a laceration, avulsion, amputation, etc.",
"But blood will still flow.",
"You've taped off a hole (the cut), you haven't turned off the pump (the heart).",
"So blood still makes it through via the smaller arterioles to feed oxygen to body parts.",
"N... | [
"On the cellular level, cells require oxygen for cellular respiration in the mitochondria. No oxygen means no breakdown of glucose means no energy.",
"On a macro-level, being oxygen deprived means there's no oxygen being inhaled. Lungs can't oxygenate the blood. The heart can't pump oxygenated blood to the brain.... |
[
"Schrödinger's cat: Is it beyond the limits of my understanding?"
] | [
false
] | I have read many sources and watched many discovery type shows, but somehow the concept of the cat being both alive and dead at the same time escapes me. I can understand that we don't know wether it is alive or dead until the box is opened, but how can we say it's both? Or is this going to take more brain cells than I have? EDIT: Thanks for the great responses, truly appreciated - I dont feel so 'inadequate' anymore | [
"That's sorta the point with the whole mind experiment. Schrödinger came up with it to show how inane quantum mechanics is when applied to bigger things. ",
"The truth is, particles are in a superposition of states until observed, then they collapse. You can't really understand that. That's just the way it is. It... | [
"Reminds me of the old joke about the mathematician...",
"A mathematician is sitting at his desk, thinking hard when his physicist friend comes up to him and asks what he is thinking about. The mathematician says he's thinking about a 23 dimensional space. The physicist looks confused and says 'how on earth can y... | [
"It's sort of a reductio ad absurdum, in that people don't have a problem with a photon being in two states at the same time, but when you make it a cat it just gets silly."
] |
[
"A doctor will clean an injection site before giving a shot - why doesn't a dentist need to do so before a numbing shot? Don't our mouths generally have more bacteria than our arm/leg skin?"
] | [
false
] | [deleted] | [
"The mouth is one of the main focuses of the immune system. Being an opening to the world, one that has to deal with decaying organic matter and whatever the hell is in the water. It has evolved different systems to keep infections in check. Saliva has a few different enzymes and proteins in it and is slightly aci... | [
"Please refer to the ",
"WHO paper",
" on best practices for injection. ",
"\"Although skin that is visibly soiled or dirty must be washed, swabbing the clean skin of a patient before giving an injection is unnecessary. Studies suggest that there is no increased risk of infection when injections were given i... | [
"Evolution doesn't have a purpose, it simply responds to pressure. ",
"The pressure to protect a permanently open hole that foreign matter purposely and accidentally enter regularly is significantly more than protecting your arm. ",
"So if something is good enough, it's good enough. "
] |
[
"Is there \"dark matter\" nearby?"
] | [
false
] | Inspired by an posted in . First off...the article linked is about as unreliable as an article can be; the tagline of the website is "Mysteries, Phenomena, Paranormal, UFOs, Space and Science," and the article quotes the Daily Mail. By itself, it's entertainment at best. However, it raises a question in my mind...if a significant fraction of the mass in the universe is dark matter, shouldn't there be a significant amount of it realtively nearby? If so, is it something we could detect or study? If we can study it up close like that, what questions (if any) would that kind of study enable us to ask that we wouldn't be able to ask if it only existed far away? Dark matter has fascinated me for a while now, ever since I saw , but it's not something I really understand. I know we can only interact with it via gravity, and that there's a lot of it, but that's about it. | [
"There are 4 fundamental interactions around us, as we know. Although most of the matter we see interacts electromagnetically, there are some examples of fundamental particles that are actually uncharged, and thus almost invisible: the neutrinos. Neutrinos are literally everywhere and there is huge flux of these gu... | [
"I'll add that there are additional attempts at direct detection on Earth. These experiments have detectors, and they wait for a dark matter particle to strike an atom in the detector and deposit some of its kinetic energy. There are no conclusive results yet, but they are really just getting started."
] | [
"There's no escaping gravitation, when someone says \"only interacts through the weak force\" gravity is taken for granted."
] |
[
"AskScience, why does the shower curtain seem to be attracted to my body when I'm in the shower?"
] | [
false
] | I thought it might be in my head, but it very clearly isn't. I'm fairly certain the two are causally linked. Not only will an outstretched hand attract the curtain, but it will keep it there. | [
"When you shower, the hot steam rises and draws air from the bottom, which pulls the shower curtain towards you."
] | [
"Hmm... How much spray from the shower are you getting when you are close to the curtain?\nYou'll notice that when you are sprayed by the shower directly, the curtain will rise less. However, if you are say, ducked out of way of the stream of the shower, the curtain will rise much more. "
] | [
"Because ",
"this",
"Cold air rushes into your shower blowing the curtain into you.",
" Just read your actual post, not just your title. I literally have no idea why your curtain is attracted to you. If things get awkward maybe its time for a new curtain. Brutal I know, but the relationship is doomed from the... |
[
"Can lahars happen in extremely cold climates?"
] | [
false
] | null | [
"Yes, lahars can be triggered in cold climates. Lahars are tephra (ash) laden mud/debris flows that occur on slopes and flanks of volcanic landscapes. How they are triggered is when rain water or snow/glacial melt occurs and undermines the slope. Even in colder climates, rain may occur and glacial melt is absolutel... | [
"Lahars form when pyroclastic material melts and/or mixes with snow and ice causing mass movement of material downslope. Often at very high speed and with lots of volume. ",
"Cold conditions are needed for the snow and ice, as is some sort of volcanic activity. Therefore they can occur in both high altitudes but ... | [
"Lahars happen much more often in cold climates because of snow and ice on the volcano as others have mentioned, but it should be said that there is such a thing as rainfall triggered volcanic mudflows of ash that's been on the ground already for a while (but sometimes very recently erupted). Those lahars have been... |
[
"Is \"same\" achievable in thermodynamics?"
] | [
false
] | What I mean is this. You have 2 objects at different temperatures: Object X is at 100 degrees, and Object Y is at 50 degrees. Slowly, you lower the temperature of X until it reaches 0 degrees, so that it is now colder than Y. Is it technically accurate to state that at one point in time, X and Y were the same temperature? I don't know why, exactly, but I've long had the idea that our understanding of quantum physics prevents this from being possible to an infinitesimal measurement. That at some instant J, object A will be hotter, and at the very next instant K, object B will be colder. What about if we talk about heat instead of temperature? Does that change the answer? TL;DR Are two objects ever exactly the same temperature? | [
"I've long had the idea that our understanding of quantum physics prevents this from being possible to an infinitesimal measurement.",
"I may be wrong, but it sounds a bit like you're restating the misconception that the uncertainty principle limits the accuracy of measurement, which it does not. A ",
" measure... | [
"The reason I made the distinction between temperature and heat is that they are, actually, distinct (though interrelated) properties. You can get two objects that are both at the same temperature, but have very, very different heat. Similarly, one object can have less heat but a higher temperature than a second ... | [
"The reason I made the distinction between temperature and heat is that they are, actually, distinct (though interrelated) properties. You can get two objects that are both at the same temperature, but have very, very different heat. Similarly, one object can have less heat but a higher temperature than a second ... |
[
"Does the gravitational constant change?"
] | [
false
] | Does the gravitational constant equal to 9.81 m/s² even apply if your outside of earths SOI? for example solar orbit or other planets | [
"That is the Earth's gravitational field at its surface, but it is not constant. It ",
"varies depending where you are on the Earth",
", and decreases as you go away from its surface. (it actually increases slightly as you go down towards the edge of the core)",
"The general formula for the gravitational fiel... | [
"It's discussed in the physicsforums article I linked. The problem with your supposition is that it assumes the Earth is uniformly dense, but it isn't. The density density distribution is such that when you go down through the mantle, you're getting closer to the much higher density core, which has a bigger effect ... | [
"No, but it's a coefficient in Einstein's equation relating spacetime curvature to energy density."
] |
[
"What happens to information that we delete off of our computers?"
] | [
false
] | null | [
"The system removes all references to it and marks it as over-writable. Think of it as a library card-catalog system - the card is removed, but the book is still on the shelf, and can be found if someone puts in the effort of looking for it.\nThe deleted data is treated the same as blank space and will be overwritt... | [
"Back in the DOS days, when you erased a file, it just over-wrote the first character of the file name with a ? ",
"This mean that the space allocated for the file was up for grabs.",
"The file and data was still there, it just didn't show up when you did a 'dir' command. Recovering erased files was pretty eas... | [
"This is pretty much still the case. That's why certain \"undelete\" programs are able to work even after you empty your computer's trash."
] |
[
"Are the distant planets that we can \"see\" still even there? How do we know?"
] | [
false
] | I've been watching some docs and doc series about astronomy and my (for one) takeaway has been that the distant planets (as in another solar system) aren't really seen, it's the light that has reflected off of them that we see (much later in time). How do we know that those planets aren't just dust today (in that they haven't been smashed to bits by something (rogue planet? a la Melancholia lol) in the time it's taken for the light has become detected)? Also, I've come to see those powerful telescopes (Hubble, etc) as not so much viewing devices (like binoculars) but the closest thing we have to time machines (due to the extreme distance/time). Am I on the right track? If not, please illuminate. Thanks! | [
"We really can only detect exoplanets within our own galaxy, and only within a small chunk of our galaxy. The most distant exoplanet ever detected is less than 30,000 light years away, and most are far closer than that. So yes, we are seeing these things as they were thousands of years ago, but that's a very short ... | [
"aren't really seen, it's the light that has reflected off of them that we see",
"That's true as well when you look at your hand in front of your face. You're seeing the light reflected off of your hand. And it takes time for the light to reach your eyes, so that by the time you see it, it's an image of your hand... | [
"We do not, but we can safely assume they are still there, unless it's a supergiant star at its late stage. That means, despite extremely large distances spanning across thousands or tens of thousands light years those planets will be still there because the relative age of stars is far longer than the travel time ... |
[
"Do lenses work for radio signals or X-rays? Do antennas work for visible light? They are both part of the electromagnetic spectrum..."
] | [
false
] | I assume that you have an antenna for visible light, or that you have a lens for non-visible parts of the EM spectrum, but they would be need constructed differently. Why, though? I have wondered about this for a while. Why would an optical lens not work for a radio signal or X-ray? | [
"Lenses do work for x-rays, but there are many problems. ",
"This paper",
" outlines them. The TL;DR is that the refractive index for x-rays is very very close to 1 for all materials, so it is hard to build a refractive lens that has any effect. Also, in the higher energy regime, the particle effects of phot... | [
"Radio frequency waves can be, and are, passed through lenses quite frequently. They aren't always geometrically similar to lenses for optical light, although their functions are the same - see ",
"rotman lens,",
" which is generally fabricated as a parallel plate structure with a dielectric inside. Propagati... | [
"I work with synchrotron radiation (5keV-120keV x-rays). For higher energies beyond about 25ish keV, compound refractive lenses are at times a viable option depending on the required numerical aperture, focal points, acceptable divergence, and acceptable energy spread. One way to fabricate them is to create parabol... |
[
"How does voluntary movement happen?"
] | [
false
] | Being a medical student (graduating in 1 year), I feel really embarassed to ask this question. I have neurology exam in 1 week and I have learned all about the pyramidal and extrapyramidal tract, alpha-gamma coactivation, motor control etc. But still I haven't been able to answer the question : where does this process originate? Where does the first action potential occur, and mainly - HOW? ; given the fact that action potential is a merely a response to an adequate stimulus. What is this stimulus, then? A thought? Are there then "thought receptors" ? I know this sounds ridiculous, but the more I think about it, the more puzzled I feel. | [
"As far as I know, the answer to your question about 'what is the original stimulus' (the thought about moving) is unknown and goes into the 'do we really have free will' and 'neural correlates of consciousness' territory. You might like to look into Libet's experiments: ",
"http://en.wikipedia.org/wiki/Benjamin_... | [
"Voluntary movement is a complex beast of an issue and is best thought of a combination and cooperation of several different areas of the brain. I feel as though trying to simplify the whole process into a single inciting event does it an injustice. That being said, I'm sure you are already reading up on this but I... | [
"Think about what you're asking here. What would a satisfactory answer look like? You've already said stimulus response doesn't quite say what you're looking for. If you're looking for a scientific explanation of the illusion of free will/consciousness you're going to have some interesting answers but little consen... |
[
"Why is the speed of light a whole number?"
] | [
false
] | I would expect it to be 299,792,458.625976 or something similar but instead it is a nice whole number | [
"The meter is defined such that light speed is exactly that many meters per second. It was changed that way in 1983. An earlier measurement ",
"from 1972",
" puts it at 299792462 +/- 18 m/s."
] | [
"It was close enough to a whole number that they slightly changed the definition of a meter in order to make the speed of light a whole number."
] | [
"In plank units its not just a whole number, its 1 ",
":)",
"Sorry your question already got answered so I just threw in something new :P"
] |
[
"When we increase the temperature of a system, the atoms in that system vibrate more. Do they increase in frequency or amplitude? or both?"
] | [
false
] | I've just been reading 'The laws of thermodynamics' by Peter Atkins. In the book he says at some point "Temperature.. is just a parameter that summarizes the relative populations of energy levels in a system at equilibrium." And "Each speed corresponds to a certain kinetic energy, and so the Boltzmann distribution can be used to express, through the distribution of molecules over their possible translational energy states, their distribution of speeds, and to relate that distribution of speeds to the temperature." Now i've heard before that when the temperature increases we say that the atoms are vibrating more. Is this increase in vibration an increase in the frequency of vibration or amplitude? or both? Is this increase in vibration due to electrons occupying higher ? What causes the vibration? (might be more of a philosophical question than a scientific one) and how does this relate to the 'speed' as described above? Does he mean the speed of vibrations, or the forward speed of the atoms? | [
"Yes, increasingly high energy states of all sorts get populated as the temperature increases.",
"Electrons interact with each other and with nuclei. A change of vibrational state can change the orbitals themselves as well as excite electrons to higher ones. And electronic energy can be transferred to vibrational... | [
"Vibrational amplitude isn't really a thing on the molecular scale. A molecule either vibrates or it doesn't. There is obviously some limit to the displacement in a bond when vibration occurs, but there's not a hard length value that the bond stretches to every time.",
"When you make a system hotter, what happe... | [
"Re: #4, Atkins is talking about the distribution over translational energy states, so speed refers to rate of travel.",
"Re: #2, just like increasing the temperature alters the distribution over possible translational energy states (i.e., adding energy makes it so that some molecules can move faster, and the ave... |
[
"Does normal metabolic function eventually return to formerly obese individuals that underwent major weight loss?"
] | [
false
] | Most articles I've read on the matter estimate that between 80-95% of individuals that achieve major weight loss regain most or all of the weight down the road, typically within a couple years. Many people, in fact, will become heavier than they were originally. It seems that more and more articles are released every week discussing the seemingly "irreversible" metabolic impact of being obese and remaining obese for an extended period of time. That got me wondering, if the duration of obesity likely impacts long-term (potentially life-long) metabolic function, could the inverse be true as well? Could there be a critical period of time that a formerly obese person must maintain their weight loss before their normal metabolic function recovers or will they always have "obesity in remission?" Does anyone know of any long-term studies that address this question? EDIT (17:30): It just occurred to me, many people that lose large amounts of fat tend to lose a significant amount of lean muscle mass as well. I wonder if this may explain some or most of the loss in metabolism observed in some studies or if that's just a gross oversimplification | [
"Part of the problem is the adipose cells. When you become overweight your adipose stem cells proliferate. If you lose weight the cells essentially deflate, but they are still there secreting hormones affecting metabolism. They are also waiting to fill back up if you fall off the wagon. Adipose cells can stick arou... | [
"You're getting a lot of answers that belong in ",
"r/confidentlyincorrect",
"The real answer is that we have some theories and a paltry amount of data that isn't of particularly high quality. Human metabolism and weight is stupendously difficult to study. Anyone who claims to know exactly when and how metaboli... | [
"Unfortunately, all of the answers you've received so far are variations on the folk wisdom that a person must only make a long term lifestyle change and then they will lose weight. And that is because, to the best of my knowledge, there are no long-term studies addressing your question. ",
"In fact, to the best ... |
[
"Is there a freezing point where meat can be effectively sterilized from bacteria as it is when cooked?"
] | [
false
] | Is there a freezing point (or method) that meat can be subjected to that can kill off possible contaminates without compromising its nutritional value? Is heat the only way to prepare possibly tainted food safely? | [
"Freezing doesn't sterilize food. You can store bacterial colonies in -80 deg C freezers for years and they come out okay. You can also flash freeze bacteria using LN2 to create something similar to 'dippin dots' which will preserve them. Some sort of media might be used, but I think the general concept holds. Free... | [
"You can store bacterial colonies in -80 deg C freezers for years and they come out okay",
"True, but to be fair, they need to be stored in glycerol to disrupt ice crystal formation. Storing them in growth media alone at -80 deg C would probably lyse most cells, but do correct me if I'm wrong."
] | [
"Conveniently, -40ºC and -40ºF are the same temperature."
] |
[
"how much do Genetics play a role in muscle building and endurance?"
] | [
false
] | do genes determine things like amount of fast twitch muscle fibers vs. slow twitch? things like that? | [
"Genes also control your ",
"endogenous",
" hormone levels (testosterone, androgens, etc) which are critical for building muscle mass and strength."
] | [
"Genes also control your ",
"endogenous",
" hormone levels (testosterone, androgens, etc) which are critical for building muscle mass and strength."
] | [
"genetically engineered \"super cows\"",
"They're called ",
"Belgian Blue Cattle",
" and it's not genetic engineering, just selecting for a mutation."
] |
[
"Is daytime darker on Mars since it is further than the sun? How does atmosphere affect the brightness of a planet?"
] | [
false
] | [deleted] | [
"Mars is about 60% further from the Sun than Earth, so by the inverse square law it gets about (1.6)",
" = 39% as much solar radiation per square metre.",
"That's appreciably darker, even considering the atmospheric effects on Earth.",
"Atmosphere reflects some of the incoming light from the Sun, and sometime... | [
"Here's something interesting. Even on Pluto, billions of miles away, it's not as dark as you might think. ",
"This calculator",
" takes your location and tells you what time of day it will be as bright as Pluto - just after sunset for me, 6:12 PM today. So yes, it will be darker on Mars than on earth, but d... | [
"A cloudy day has <25% of the light of a sunny day, so it is a bigger factor.",
"Basically, mars looks like it's cloudy all the time during daytime."
] |
[
"What would happen if we nuked a hurricane?"
] | [
false
] | [deleted] | [
"Funny you should ask this. It gets asked so often NOAA (the National Oceanographic and Atmosphere Administration) actually made a response you can read ",
"HERE",
".",
"The short answer, nothing. The amount of energy a fully developed storm has is magnitudes more than the amount of energy a nuclear bomb coul... | [
"Now what if one were to drop several thousand spiders into this giant radioactive hurricane?"
] | [
"Perhaps we could also dump tonnes of sedative into the storm to keep the spiders nice and docile.",
"And who knows, maybe we could increase the amount of...electricity? "
] |
[
"How does the mRNA-1273 vaccine that Moderna is testing work (or is expected to)?"
] | [
false
] | null | [
"In general, mRNAs are translated into proteins. For an mRNA vaccine, some mRNAs that match target viral mRNAs are injected, which causes your cellular machinery to translate them into the viral proteins. These are not functional viruses but rather are disassembled parts of the virus that the body can recognize. Yo... | [
"No, sorry for the confusion. The things that your body makes are the ",
", which are parts of the virus. The thing that’s injected (the mRNAs) are copied from the virus’s genetic code. Your body reads the injected mRNAs like a blueprint and then starts constructing viral proteins.",
"Edit: ",
"viral mRNA co... | [
"You only need to know the genetic code (sequence) of the virus. Once you have that you don't need any viruses.\nYou can then just synthesize mRNA based on the sequence that you already know.\nModerna then packages this synthesized mRNA into nanoparticles and injects them into a patient. \nOnce injected the nanopar... |
[
"We have been measuring the age of earth by looking at the layers of ground, how do we know there aren't any older evidence underneath the thick snow of North pole? Or the deepest ocean floor that human has yet to discover?"
] | [
false
] | We have been measuring the age of earth by looking at the layers of ground, how do we know there aren't any older evidence underneath the thick snow of North pole? Or the deepest ocean floor that human has yet to discover? Or even unknown creatures that lived before the dinosaurs.. Edit: I don't mean literally looking at the ground alone, what I meant was looking at the stuff/rocks that is from underneath the ground. Since anything from that long ago probably got buried for a very long time.. | [
"Lets start by having a look at the ages of material we ",
" observed.",
"The first blunt observation we have is that the age range of geological materials is much narrower for oceanic rocks than it is for continental rocks. The oldest oceanic crust is about 340 Ma old, in the eastern Med basin; most oceanic c... | [
"Or even unknown creatures that lived before the dinosaurs..",
"Other users can handle the geology question, but for this I'd like to point out that ",
"Dinosaurs only showed up fairly recently on the time frame of the history of the entire Earth,",
" and we have discovered countless animals that predate them... | [
"A million years is a Mega annum (Ma)",
"A billion years is a Giga annum (Ga)"
] |
[
"If we only drank water every three days, how much would we have to drink?"
] | [
false
] | null | [
"This question depends on so many things. What kind of activities are you engaging in each day? Are you eating food that contains water at the same time? Average temperature of your surroundings? How much does this hypothetical person weigh/gender/age/metabolism?"
] | [
"Wow, I can't believe I didn't think about those things to add them in, thanks, I'll edit."
] | [
"How about if we assume an \"African bushman\" lifestyle? Surely our species had to survive for a while without water 50,000 years ago."
] |
[
"Is it possible for a star to orbit a rocky body?"
] | [
false
] | Would it be possible for a mass that can sustain fusion orbit a rocky body given the mass of the rocky body would need to be greater? | [
"Technically, one body doesn't orbit another; they both orbit their common center of mass. But for a planet orbiting a star, this center is basically at the position of the star.",
"Whether a body will undergo fusion or not is dependent on its mass. If it gets big enough, it becomes a star.",
"Basically, no ro... | [
"No there couldn't, stars attain fusion due to their mass, so if something weighs enough for a star to orbit it because it is heavier then that object will also be undergoing fusion, in other words it will be a star. "
] | [
"No there couldn't, stars attain fusion due to their mass, so if something weighs enough for a star to orbit it because it is heavier then that object will also be undergoing fusion, in other words it will be a star. "
] |
[
"Is there a hormonal difference with people who live in consistently cold climates compared to people in warm climates?"
] | [
false
] | It seems like (just an example) eskimos compared to natives in the tropics have extremely different body structures; even though it could be simple an evolutional difference. I am just wondering if their bodies have different homeostatic levels of hormones. | [
"Based on day-night cycles, there is absolutely a difference.",
"http://www.ncbi.nlm.nih.gov/pubmed/7982827",
"Additionally, vitamin D from sun exposure can affect metabolism, bone growth, mood disorders and a number of other things potentially blamed on \"hormones\"."
] | [
"what about person who has moved from warm climates to severe cold climates? how do they get ill affected and what remedies can be done to counter these changes? "
] | [
"Simple and even folk remedies are often effective enough, in my understanding. Drinking vitamin D milk or using tanning beds can help, as can artificial lighting to prevent Seasonal Affective Disorder. All-in-all, humans are very adaptable and the changes will be readily made in time.",
"http://www.mayoclinic.co... |
[
"Is the threat of a nuclear EMP attack as serious as they say?"
] | [
false
] | I understand that a nuclear explosion puts off an Electro Magnetic Pulse that radiates around it and can negatively effect (if not disable) surrounding electronic devices. Though my impression was that once the EMP was past, you could just just restart your computer or turn back on your tv with the consequences that you might have to replace a few fuses. However, I then started hearing US National Security Experts talk about how a single bomb, detonated a couple hundred km up, would create an EMP that could cripple virtually the entire country for years. "An electromagnetic pulse (EMP) attack on the American homeland, said one of the distinguished scientists who testified at the hearing, is one of only a few ways that the United States could be defeated by its enemies – terrorist or otherwise," wrote Sen. Kyl "And it is probably the easiest. A single Scud missile, carrying a single nuclear weapon, detonated at the appropriate altitude, would interact with the Earth's atmosphere, producing an electromagnetic pulse radiating down to the surface at the speed of light. Depending on the location and size of the blast, the effect would be to knock out already stressed power grids and other electrical systems across much or even all of the continental United States, for months if not years." From this and other sources, I get that they are implying that all ROM chips, SSDs, unshielded storage, etc would be wiped. Thus all bits of machinery and electronic equipment that runs our everyday lives would "forget" how to do their jobs and virtually all technology (including cars) would be useless until they were repaired (had their ROMs replace/reflashed) - thus not just a simple 'restart'. I'm a bit of a skeptic, so I question it when someone who's authority comes from worrying people with threats of attack, tell me about the potential damage of an attack. Can anyone give me an accurate scientific understanding of just how devastating such an EMP attack really would be to our lives? EDIT: Found but I only understand about half of it. | [
"EMPs don't erase ROMs. They physically destroy chips. The parts would have to be outright replaced, not reprogrammed."
] | [
"Ok, so all personal computers, cell phones, ... basically anything more sophisticated than a toaster will be useless until you replace the ROMs in them?",
"Any insight into the radius of such an effect?",
"I've heard it said that one exploded over Kansas would affect the entire continental US. Does \"affect\" ... | [
"First, the devices would be useless period; we would have to outright replace all damaged circuits.",
"As for the affected radius, I don't know. But wikipedia mentions that Starfish Prime damaged electronics ~1,300km away."
] |
[
"What properties of matter dictate it's malleability/ductility?"
] | [
false
] | I had assumed it would correlate to density, but after some preliminary research it apparently isn't that simple. | [
"The properties of metals (and of most solids) are determined by the material's ",
"crystal structure",
". The effects of crystal structure can be expressed in both macroscopic and microscopic terms. ",
"On a macroscopic scale (what makes this beam/girder/bar) ductile/malleable: the macro properties depend on... | [
"Turbine and Simon seem to have pretty much nailed metals but I think it's worth mentioning that there are materials that, for a few different reasons, defy that type of analysis. ",
"Within the category of \"crystalline\" materials, there is variation in the type of bonding, which is heavily dictated by electron... | [
"To add to Turbine_Heart, the malleability and ductility also have to do with microscopic imperfections in the crystal structure called \"dislocations\". Visually this look like snakes or cracks. Dislocations form when ever there is relative movement between nodes in the crystal structure like in fast cooling of a ... |
[
"What exactly happens when you hit the Ulnar Nerve (aka Funny Bone)?"
] | [
false
] | Hey Reddit, I was wondering if you could help me out with this one. I know how a nerve is stimulated, and how action potentials are propagated down nerves to send signals, but what I don't understand is why when you hit your "Funny Bone" it only sends those signals one way (towards the hand, where the nerve continues/innervates). My main question is: Does anyone know why this pain doesn't shoot up the arm and towards the body? I can't find it in any textbooks, I can only find why it shoots down the arm/towards the hand. If you're pinching that ulnar nerve, why wouldn't it cause pain up AND down, or even just more localized than sending the signal down? Thanks Reddit! | [
"When the ulnar nerve is hit with force in the elbow region, most of the nerves that are passing through that point are stimulated. This means that the nerve sends a signal to the brain, which is interpreted as pain/dysaesthesia in the region the ulnar nerve innervates. \nThis is why you feel part of your hand ting... | [
"You would be correct, I didnt see your post before I answered. I could have saved some time and just given you my upvote hahah."
] | [
"When your elbow is bent, the ulnar nerve gets trapped between the bone and your skin. When you whang your bent elbow on something (this is extremely technical), it triggers action potentials in the axons (nerve fibers) that are compressed.",
"There are two types of axons in your ulnar nerve: ",
" (from the ski... |
[
"Do people retain information better depending on the color of light source they're under?"
] | [
false
] | I'm not sure if that's a dumb question or not. | [
"It's worth noting that Osram is an enormous (the biggest?) lighting manufacturer and has a large incentive to create markets for new speciality lighting systems. "
] | [
"I don't think that's dumb at all, rather interesting, but complicated question!",
"There's ",
"that",
", a study of the effect of \"biological lighting\" on students, so that's close-ish to what you ask..."
] | [
"Certain people?? With certain unique conditions? Possibly. Edit: synesthesia can give color unique effects on perception.",
"It's important to clarify the question here. If your asking if different conditions such as the color of light or colors in general can effect mood and mind then.... Yes...",
"It is beli... |
[
"What is the scientific definition of odourless?"
] | [
false
] | I recently had an inconclusive discussion about the nature of odour, and the question came up; is 'odourless' based on whether a human/known animal can smell it, or is it actually a chemical property which makes a compound odourless to every possible lifeform? | [
"Visible light spectrum/infared and how animal can or cant. I suppose you could use the same way of thinking a \"smell\" spectrum?"
] | [
"Odor or smell is not a real property of anything. It is based on our perception. ",
"Our noses contain receptors that can bind certain chemicals that causes our brains to perceive a \"smell\". Different chemicals that bind in different combinations to these receptors causes different smells to be perceived by ou... | [
"I dont think a \"smell\" spectrum might work. we can measure light objectively but i havent heard of an instrument to measure odor. you can measure the concentration of known smelly compounds, but besides expirience there is no way to tell if comp A stinks worse if comp B is also present and so on.",
"Also the h... |
[
"Can someone explain how DNA/RNA microarray imaging works using laser excitation? How does one go from a hybridized cRNA transcript to an intensity value?"
] | [
false
] | Basically, I understand the principles behind hybridization of transcripts to microarray probes, but how does the imaging machine excite the fluorescence and correlate such a dense sample set to intensity values for expression analysis? | [
"This question might be better suited for ",
"/r/askscitech"
] | [
"Get cDNA, label with fluorescent dye, hybridize. Excite array with usually blue light, take a picture through a green filter and magnifying lens with a CCD camera. Camera converts light signal as a function of position to intensity values for you."
] | [
"The probes are labeled with fluorescent dyes, i.e. molecules that emit a certain wavelength of light when stimulated with a different wavelength of light. The intensity of the emission, which ought to correspond to the amount of probe that hybridized, is measured with a camera.",
"I'm not sure what you're asking... |
[
"Why do photons always move at the same speed?"
] | [
false
] | null | [
"Special relativity says that a particle with zero mass must always move at c."
] | [
"It does answer his question, because it tells OP what to look for. This is how scientific articles work. It would not be reasonable to describe the entire underlying theory for your work in a publication, the article would become way too long. Instead, you have several dozen references to other articles that your ... | [
"It does answer his question, because it tells OP what to look for. This is how scientific articles work. It would not be reasonable to describe the entire underlying theory for your work in a publication, the article would become way too long. Instead, you have several dozen references to other articles that your ... |
[
"Why can't we harvest energy from lightning?"
] | [
false
] | null | [
"We can, we just can't store enough of it to be meaningful.",
"Lightning is a huge amount of energy over a very very short period of time.",
"We can capture some of it, but we don't have the battery capacity to store it, or a battery capable of being charged that fast without melting",
"Catching the energy is... | [
"True, but I sorta figured that he was asking why we didn't use lightning as a source of power."
] | [
"Imagine the infrastructure you would need to capture a lightning bolt and put it on the grid. First, you would need some kind of a tower capable of carrying thousands of amps of current. This would feed into a huge capacitor bank with a few gigajoules of capacity at hundreds of millions of volts. Based on my calcs... |
[
"Do we know much about the limits of human physical achievement with supplemental oxygen?"
] | [
false
] | My friend and I were out for a 10 mile run today, and we started talking about what would happen if you took a champion runner (any aerobic distance) and had them run the same race with supplemental oxygen. How fast could they go? If pure or highly enriched oxygen were available, what would be the limitation on their speed? Could a human run a 10k race or marathon at the same speed as a sprinter? | [
"In general, oxygen will help slightly but there are many factors involved in such athleticism. For a 10k race, your metabolism changes drastically throughout the course of such exercise. First you will burn through your ATP stores. Second you will begin to use glycogen, and third fat. This is a limiting factor as ... | [
"My lab has done research in which we provide supplemental oxygen to elite and amateur endurance athletes at a level that would mimic 17,000 ft below sea level. The improvements were equivocal or marginal at best. Oxygen delivery isn't the main limiter of human performance. In fit people it's not an especially s... | [
"When I was taking a scuba class I had an old fart of an instructor, and one time he was talking about diving in his younger days and how after a night of heavy drinking, him and his buddies would simply take a few huffs out of an O2 cylinder and their hangovers would almost immediately be alleviated...given that b... |
[
"Why can't fusion happen with elements heavier than iron?"
] | [
false
] | [deleted] | [
"That’s not a true statement, you can pretty much fuse anything with anything. However the Q-values for fusion reactions of two heavy nuclei tend to be negative, so the reactions are endothermic. So that makes these heavy ion fusion reactions undesirable for applications where you want to use the reactions to relea... | [
"Unfortunately, most of what you’ll find on the internet just reinforces the oversimplified statement that I mentioned. Rather than trying to fit all of the behavior of reaction Q-values into a soundbyte, I’d recommend just playing around with Q-value calculators like ",
"this",
". You can use that for arbitrar... | [
"That’s interesting. Do you have any web sources that explain this further?"
] |
[
"How are orbiting objects not accelerating due to gravity?"
] | [
false
] | We constantly describe orbits as falling, but going so fast horizontally, that you miss the planet. When you fall you accelerate towards, but satellites in a perfect circular orbit are traveling at a constant speed. | [
"You're simultaneously asked two questions, let's address the first.",
"We constantly describe orbits as falling, but going so fast horizontally, that you miss the planet. When you fall you accelerate towards, but satellites in a perfect circular orbit are traveling at a constant speed.",
"Acceleration doesn't ... | [
"Acceleration is a change in velocity, not speed. Velocity is a vector quantity (i.e. it has both a direction and a magnitude) and so the change can either be in the magnitude (a change in speed) or the direction. Unfortunately, we don't have a separate word for the vector acceleration, so that fact that you asso... | [
"If you are changing direction constantly, like in an orbit, you are accelerating as velocity also has a directional component, and acceleration is change in velocity. ",
"This is why you can simulate gravity by being a rotating structure around a spaceship, as depicted in many movies (2001, Interstellar, and oth... |
[
"Is there any advantage to using anti-bacterial dish detergent over the regular (presumably non-anti-bacterial) detergent?"
] | [
false
] | With respect to both washing dishes and washing hands. Would the regular detergent do the job just as well? Is the anti-bacterial tag just a gimmick? | [
"In most cases, not really. The main antibiotic ingredient in these antibiotic soaps is triclosan, which is a really good antibiotic, just not one which we can take (its not very bioavailable). These detergents will kill more bacteria than standard detergents, in fact 2% triclosan washes are standard procedure in h... | [
"it \"feels\" healthier to the public",
"This is certainly why I buy it. Thanks for the info! Very helpful."
] | [
"Breeding super bugs? Really all dish soap and very hot water works to kill bacteria and by thoughly cleaning, then drying your dishes you make them less habitable for bacteria to grow, but as soon as you touch the dishes with your hand you are reintroducing bacteria. Everything you eat, or use to eat is covered ... |
[
"What is there in between neurons?"
] | [
false
] | I was sitting in today's Histology course and realized that although I have this idea iin my head that neurons are apart, I don't know what is the medium in between neurons. I noticed on an electron microscopy image that they seem to be relatively tightly packed. (axodendritic and axo-axonic synapses were being explained). I suppose it depends on what type of neurons we're talking about but perhaps some of you can offer some explanation, perhaps this is a stupid question to ask but still it hasn't been explained to us and I can only offer guesses. | [
"You might be thinking of a ",
"chemical synapse",
". The space between two neurons making a synapse is called the ",
", and is filled with ",
"extracellular fluid",
". Mostly water, but with plasma and ions and other stuff in solution."
] | [
"Mostly ",
"glial cells",
" (which are \"support\" cells for neurons) and blood vessels"
] | [
"It will vary a little depending on which part of the nervous system. For example, gray matter contain the neuronal cell bodies in the brain, and it has what is referred to as neuropil between them. This is a broad term for glial cells, and a dense network of axons and dendrites. Particularly the axons and dendrit... |
[
"So what's the big deal with genetically modified food or GMOs? Why are people against it?"
] | [
false
] | [deleted] | [
"One sensible fear is that a non-invasive species might be transformed into an invasive species. For example, if you were to engineer a species of corn that contains natural insecticides, that might turn out to be a survival advantage. That species of corn might end up thriving in places where corn doesn't normal... | [
"As is elaborated in some of the other comments, GM crops could fundamentally change some ecosystems, which can be very carefully balanced. If GM crops are unregulated (politically, biologically, economically, or something else), they may begin to change the ecosystem and corrupt that balance, having adverse effect... | [
"That's more to do with the fact that genetically engineered seed is also hybrid seed. Hybrid seed does not produce seed that is suitable for replanting (it can be replanted, it just produces progeny that aren't as good). Farmers decided, back in the 1930's or so, that buying new hybrid seed every year was better... |
[
"what would it take to build walking talking intelligent synthetic life?"
] | [
false
] | I realize we are a while away from such a thing. But its been bugging me for a while, so I figured I'd ask. Are there groups or people seriously discussing such things? | [
"Are there groups or people seriously discussing such things?",
"Yes. Quite a lot of us, actually :)",
"what would it take to build walking talking intelligent synthetic life",
"Whoa, whoa. There are like three questions here you need to separate:",
"walking",
"Better robotics. See research on bipedal rob... | [
"Are there groups or people seriously discussing such things?\n",
"Yes. Quite a lot of us, actually",
"where?",
"I realized I asked a lot, I just find it rather fascinating. now to be a bit clearer, I think you think I was referring to computer AI exclusively. But I was wondering more so about synthetic biolo... | [
"That's similar to asking the meaning of life and why as humans we have the will to live.\nOther than electrical signals and chemical changes in the brain responding to cognitive functions, it is impossible to say why we do what we do.\nWe have the programs in place for a robot to walk, respond to it's surroundings... |
[
"What is happening at cellular and tissue levels in “muscle knots”?"
] | [
false
] | null | [
"At the neuromuscular junction between motor neurons and muscle tissue, the motor neurons release a chemical called acetylcholine which triggers the muscle tissue to contract. When the motor neuron is damaged or recieves abnormal signals (e.g. from a nerve being pinched) it releases more acetylcholine than usual wh... | [
"Jumping on board with some simple links:\n",
"https://en.m.wikipedia.org/wiki/Myofascial_trigger_point",
" \nWiki also has some paper links. Pubmed also has a lot with simple keywords such as 'trigger point theory'.",
"I'd also like to point out that trigger point theory is very common among healthcare pract... | [
"I work in Physical Therapy and work with Trigger Points. I just want to second the statement that the muscle with the Trigger Point does actually need to be stretched (gently) and strengthened in its proper biomechanical position to help prevent it from occurring again. ",
"For example, if one has a Trigger Poi... |
[
"Does a manual car save more gas going down a hill in neutral or in gear?"
] | [
false
] | I've argued this with friends before, many people say putting the car in neutral while going down a hill saves gas. So the parameters of the question: Is it more gas efficient to go down the slope in neutral or in gear? Is the answer different if the slope is considerably more steep (can accelerate your care if it were in neutral?) | [
"Definitely in gear. Fuel would be needed to keep the engine idling while in neutral, whereas momentum will keep the engine spinning while it's in gear. The car will sense that there is no load on the engine and cut fuel off."
] | [
"Thanks so I think we can summarize it as follows. If you are going down hill at constant speed in neutral, then switch to gear, if after switching the car is going",
"(this can be seen by analyzing what happens in each case, or simply by noting conservation of energy)"
] | [
"This is actually incorrect, regardless of the car design.",
"The question is worded such that the hill's steepness keeps the car at the same speed, whether it's in neutral or in gear. This means that even if the car stops delivery of fuel when it senses engine braking, that would not be applicable here, because... |
[
"Do water droplets reach a uniform volume before gravity overcomes adhesion and the drop drips?"
] | [
false
] | I know that rain droplets can vary in size, but what about water dripping off of a surface? The drops seem much closer in size. | [
"No. The oscillations of the water left on the surface will affect the size and time of the next drip. In this way successive drops are causally linked. The time between drips will follow a repeating pattern with an increasingly long period. Eventually the period on the drip pattern will tend to infinity and the dr... | [
"Mind blown. Is there a maximum volume of a drop of water? "
] | [
"Droplet size is a way to measure surface tension of a liquid. Using a syringe and water, you can cause a droplet to grow on the end of the needle until gravity overcomes the adhesive force and causes it to fall. In that case, if the water is all the same the droplets would be the same size, and the system can be s... |
[
"Why aren't we using more Heliostats/Power Towers?"
] | [
false
] | They seem like a really cool/powerful invention. The mirrors adjusting for the sun would draw a bit of energy, of course, but the focusing of the light should more than make up for it. | [
"More expensive per unit energy than fossil fuels."
] | [
"I think that article stated that a new nuclear plant is $2-3/W, and that the costs for coal plants have been \"similarly unstable\" -- not necessarily similar. Many of the stated reasons that coal and nuclear plants have been getting more expensive probably apply to solar plants as well.",
"When you see an \"11 ... | [
"Because it's cheaper (for now) to just burn more coal, oil or gas. It also needs a lot of land and, of course, a lot of sun."
] |
[
"How can a human survive a 300 degree temperature change?"
] | [
false
] | , there is an activity called the 300 club in which people go from a sauna to swimming in Antarctica. The body undergoes a 300 F temperature change. How is this possible without getting hypothermia or going into shock? I assume there is some internal homeostatic effect that is going on that will protect the body for a certain amount of time. The wiki says that alcohol aids in this, but I thought that warmth from alcohol was a placebo? Basically I'm wondering how it's possible! | [
"The human body thermoregulates and it does this extremely well. A 300 degree temperature change in the external environment, especially for a very brief period of time will hardly effect the bodies core temperature. Let's say you set your oven to 300 degrees and briefly stick your head inside, yes it's hot, no you... | [
"To expound, in a really simplistic way. Buy a 6 pack of soda at room temperature. Throw it in the freezer for 5 minutes - take it out and drink it.",
"It will be barely colder than room temp. And soda doesn't have many homeostatic mechanisms for thermoregulation like the human body."
] | [
"They actually go from a 200F sauna to a -100F outdoor temperature (not swimming, which would be only 32F or a bit lower if the ocean is freezing).",
"In either case, however, you go hypothermic fairly rapidly. If you jump into a sub-freezing ocean -- I've done it -- you only have one thought, and that's GET OUT ... |
[
"Do blind people experience a circadian rhythm?"
] | [
false
] | Or is there a different cycle responsible for helping manage daily fucntions? | [
"I've been totally blind since about the age of 5.",
"When I was about 11 I participated in a sleep study in Oregon about this, measuring the levels of melatonin via saliva samples.",
"I guess it was considered very rare to be able to wake up with the sun totally blind but I was apparently doing it.",
"As I g... | [
"\"Most blind people with no perception of light, however, experience continual circadian desynchrony through a failure of light information to reach the hypothalamic circadian clock, resulting in cyclical episodes of poor sleep and daytime dysfunction.\"",
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3202494/"
... | [
"Follow up question: If a blind person set an alarm and went to sleep and woke up at the same time everyday would they develop a natural circadian rhythm? If so, without the alarm after two weeks would they experience disymetry again in their sleeping patterns?"
] |
[
"Does potential energy \"count\" as energy?"
] | [
false
] | To clarify, if I were to lift say, a few kilograms of matter a kilometer up, and then combine it with anti-matter, would it release more energy than if I were to combine it on the ground? | [
"I somehow miss your sub-question, and I gave an answer. I will keep some of what I wrote there, maybe you will like it.",
"Maybe you didn't realize it, but gravitational energy is also consider/named potential energy. Why? because it has the potential to generate a force (gravitational force in this case) if you... | [
"Somewhat related to your question: Did you know that a compressed spring becomes heavier by e=mc",
" "
] | [
"Yeah, it's the sub-question that I am curious about.",
"So when the potential energy of something goes up, e.g. Going up a mountain, does it's mass go up?"
] |
[
"Is it harmful to live close or under high-voltage power lines?"
] | [
false
] | Is it harmful to one's health in any way at all to live near them? I'm talking about the one's that are high in the air not the residential one's that you can climb with a ladder. | [
"\"I've talked to one of my professors who did a proof in class which showed that it isn't possible for the transmission lines to affect you.\"",
"Without reproducing his reasoning, that's a rather hollow statement."
] | [
"This is a single study I found, submitted to BMJ, I'm not at my home institution so I couldn't read the whole thing but i'll leave it here.\n",
"http://www.bmj.com/content/330/7503/1290.abstract",
"This study did find a 1.69 factor increase in lukemia of those living within 200m of a high voltage power line.\n... | [
"From the cited abstract:",
"There is no accepted biological mechanism to explain the epidemiological results; indeed, the relation may be due to chance or confounding.",
"http://www.who.int/mediacentre/factsheets/fs322/en/",
"From the factsheet:",
"However, the epidemiological evidence is weakened by metho... |
[
"How do carrion birds and other scavengers keep from getting sick?"
] | [
false
] | Doesn't decaying meat have all kinds of nasty things in it that make animals sick? | [
"Typically they have extremely low pH in their stomach acids which is enough to kill off pathogens which would be harmful to humans.",
"Carrion feeders like Vultures have stomach pHs of around 1-2 (",
"Houston and Cooper 1975",
"). More standard carnivores like lions also have pH around 1 in their stomachs, w... | [
"As BillTheDoor says, low pH stomach acids is there main defence. As an added defence, most carrion birds are bald (that's what gives them that evil look) so they can stick their heads inside a carcass and not get a bunch of nasty stuff trapped in their head feathers.",
"Most animals that eat raw prey have pretty... | [
"It's a natural adaptations to their diets, they produce stomach acids with a lower pH than non-carnivores. ",
"Stomach ulcers are actually caused by a bacterial pathogen, Heliobacter pylori. So I don't believe the different pH would have any impact on ulceration rates."
] |
[
"How do sensory neurons exactly communicate? (contrary to motor)"
] | [
false
] | Effector(motor) neurons send neurotransmitters, like acetylcholine which is absorbed by muscles inducing the sacroplasmic reticulum to release calcium which exposes actin binding sites for the myocin heads to bind and crawl up (using ATP.)--> contracting muscles. But how do sensory neurons instigate one and other? What neurotransmitter do they use? How does the chemical reaction work backwards from the source to the brain? I couldn't find much information about sensory neurotransmitters. Would greatly appreciate if someone could point me in the rigth direction. I fear, could there be several different neurotransmitters specific to heat/pressure/oldfactory, etc. protien complex sensors? | [
"In addition to efferent motor neurons, there are afferent sensory neurons. There are a number of different types, but for the sake of simplicity, we'll just assume they all work the same. The sensory system has less to do with what neurotransmitter, and more to do with what stimuli the neuron responds to. There... | [
"I understand. Would you happen to know what neurotransmitters are specific to sensory only? Not inhibitory but exciting neurotransmitters. Also, im under the impression that the neurotransmitters aren't specific to which receptor initiates a stimulus. Your indication \"more to do with what stimuli the neuron respo... | [
"Far and away the most common neurotransmitter for sensory neurons is glutamate. Almost all neurons with far-reaching projections (think, from your toe to your brain stem) work via glutamate. Motor neurons work via acetylcholine (ACh). They dump ACh onto muscles across the neuromuscular junction, causing them to de... |
[
"To what extent is the saying 'You are what you eat' true? How much of me is molecularly rearranged chocolate milk?"
] | [
false
] | I'm mostly looking for a qualitative answer, but if numbers help, let's say 150 lb person who eats a 2500 calorie diet, 500 of which come from chocolate milk. | [
"Ok, let's break down what's in the chocolate milk, shall we?",
"Water: most of the water we take in makes it out unchanged, or if it is incorporated, is kicked out soon thereafter.",
"Carboyhydrates: broken down and metabolized for energy. The carbon leaves in your breath as carbon dioxide, the oxygen and wate... | [
"Thank you!",
"I'd never made the connection between carbon in carbohydrates and carbon dioxide when we exhale. That's cool. ",
"It seems like your answer kind of approaches the chocolate milk as a one-time intake. But what if it's a consistent flow that reaches a 'steady state' presence in my body. Old chocola... | [
"Food intake is discrete, yes. We eat a meal, it's consumed for energy. That energy is used and the excess is stored as either fat or glycogen, and once the initial meal has been digested, those reserves are tapped to continue metabolism between meals.",
"If you were somehow managing a steady-state intake of food... |
[
"Is it possible to boost the speed of sound up to the speed of light?"
] | [
false
] | null | [
"There is reason to believe that the fast any sound can get is ",
"57% the speed of light",
", but this isn't rigorously proven. It may be faster in extreme environments like the cores of neutron stars."
] | [
"You’re in a photon gas right now. Photon gases are everywhere, they’re not particularly “extreme”."
] | [
"What if the ligth is slowed down by some means? Can sound travel faster than the ligth it is using as a medium?"
] |
[
"The vehicles used in the cleanup after the Chernobyl disaster (1986) are still too radioactive to be around safely. Is this beacuse the metal in the cars has become ionized, or is there radioactive material embedded in them?"
] | [
false
] | null | [
"After the Tokaimura nuclear accident, where several Japanese nuclear workers were exposed to neutron radiation because of a criticality accident (a nuclear chain reaction), scientists were able to estimate the dose each worker received by examining the 5 yen coins in their pockets, the neutron radiation created so... | [
"Do you know which material in the vehicles have been activated? Are there any radioactive isotopes of iron? Or would it be trace metals that have become activated?"
] | [
"Do you know which material in the vehicles have been activated? Are there any radioactive isotopes of iron? Or would it be trace metals that have become activated?"
] |
[
"AskScience AMA Series: I am /u/CosmoSounder and I study the processes inside supernovae. Ask Me Anything!"
] | [
false
] | Hi everyone. I do theoretical and computational work on supernova neutrino oscillations and nucleosynthesis. I have worked with trying to predict the neutrino output of a star undergoing the early stages of supernova, and am currently working on a project that will examine the feedback process between neutrino oscillation and nucleosynthesis in supernovae. I should be available between 12-2 EDT (17-19 UTC). AMA! | [
"Hi ",
"/u/CosmoSounder",
", thank you for doing this AMA. I am about to start my undergraduate degree in astrophysics and am completely obsessed with the field and especially the physics of stars.",
"I recently asked a question on AskScience that didn't gather much interest and was wondering if you could may... | [
"So this is actually outside of my area of research, I actually don't really know anything about Thorne-Zytkow objects, so everything that follows is pure conjecture based off what I know of neutron stars, Giants, etc. ",
"The neutron star core will almost certainly affect the remining life span of the Giant. It'... | [
"So if you look at the table of the ",
"standard model",
" you'll see that there are three different \"flavors\" of neutrino, electron, muon, and tau. We also know that there are three neutrino masses, and since physicists are creative we call them mass 1, 2, and 3. The problem is that the mass states don't lin... |
[
"In North America, periodical cicadas (magicicada) have life cycles of either 13 or 17 years, depending on their brood. What is the significance that both of these numbers are prime?"
] | [
false
] | And why are there no magicicada broods or other cicada subspecies on 7, 11, or 19 year cycles (those also being primes), or are there? | [
"Because they're prime (actually, relatively prime is enough, but primes are relatively prime to everything but their multiples), the length of time between double-emergence years (which is the least common multiple of their cycle lengths) is maximized. For example, with 13-year and 17-year cicadas, you only have a... | [
"More importantly, a prey-type of creature having a prime-number life cycle would not sync up with many other organisms' life cycles.",
"If a cicada had a life cycle of 12 years, it may have been threatened by a predators with life cycles of 2, 3, 4, 6 and 12 years. Imagine a predator with a life cycle of 4 years... | [
"It isn't totally known. However, most of the current guesses (based a lot on mathematical modeling) suggest that having a prime life cycle that is also relatively long helps (1) prevent predators from being able to sync their life cycles with yours and (2) prevent inter-brood competition.",
"Here's a good paper:... |
[
"Why are viruses that result in a global pandemic so rare?"
] | [
false
] | [deleted] | [
"A pandemic usually requires a virus that can infect human which is new and distinct enough that there is not pre-existing immunity, but well adapted enough to spread quickly and has the right characteristics to escape containment. As for why it's \"so rare\", I'd point to the last one. We ",
" have an influenza ... | [
"Sure, but SARS onset was sooner after exposure and most importantly typically started with a clear fever. You are correct though that we got lucky, but it wasn't exactly a fluke die off. If it didn't have that clear fever right away it might have been a much more terrifying situation."
] | [
"“Emergent Infectious Diseases” occur about once a year, but most of them don’t reach pandemic-level. ",
"The reason we don’t have more pandemics is because they need to be in a sweet spot of circumstances, particularly in reference to their symptomology. If the symptoms are too slight the disease may be difficul... |
[
"If a human were to have a blood transfusion with a blood type that was not their own, what would happen?"
] | [
false
] | null | [
"serious medical problems.",
"This is more what I was interested in. Could you please elaborate?"
] | [
"Because of the way the body recognizes the proteins on the erythrocytes (red blood cells), it depends. A simplified way of looking at it is purely using blood types. ",
"Let's say person 1 has type AB blood. That means their blood cells have protein A and protein B on them. If you were to give them blood without... | [
"Your body just completely goes into attack mode. Your antibodies would bind the red blood cells from the transfusion and these would be destroyed by your immune system. This is called an acute hemolytic transfusion reaction. This is accompanied by low blood pressure and fever, due to the activated immune response.... |
[
"Is looking through a mirror same as looking at a distance for eye health ?"
] | [
false
] | null | [
"Focal distance in a mirror is eye to mirror + mirror to object"
] | [
"so say if distance to relax your eyes is 6 m and you look at yourself in a mirror which is 6m away that will relax your eye ?"
] | [
"No, that would be 12m. 6m is to focus on the surface on the mirror. Your reflection is \"behind\" the mirror"
] |
[
"Why are the evolutionary advantages of being a snake? (having no limbs, lack of eyelids/external ears, etc.)"
] | [
false
] | I know a little about reptiles and amphibians from my earlier days of studying them out of interest, but from what I understand they are hard to place in the evolutionary tree, are often excluded when talking about reptilian ancestors, and hardly ever seem to come up in discussions about evolution unless you are specifically studying them. Are they "newer" than lizards, amphibians, and such? edit: Sorry I meant "what" in the title | [
"Large amounts of genetic data have consistently placed snakes as the sister group to the group composed of Anguimorpha (monitor lizards, Gila monsters, and their relatives) and Iguania (iguanas, chameleons, and their relatives), as in ",
"this study",
", which is one of the best studies of higher-level squamat... | [
"oh wow, I was obviously misinformed then. Thanks for all the info, I'm going to check out that study"
] | [
"To be fair, most of the relevant genetic work on deep-level squamate relationships has occurred within the last 10 years or so. Before these studies, relationships among the major clades of squamates were estimated based on morphology (primarily skeletal characters), and snakes were problematic in many of these an... |
[
"If my goal is to witness as much sunlight as possible In a 24 hour period on the winter solstice, would I achieve this by going towards the equator or by traveling west?"
] | [
false
] | Assume that you start in New York, and you can only travel in speeds allowable by a car - say 100 mph. Additionally, is the optimal route actually some combination of west and south due to the curvature of the earth? | [
"At the solstice, the ",
"formula",
" for the number of hours of sunlight is:",
"(24/pi)*acos(tan(x*pi/180)*tan(23*pi/180))",
"Where x is your latitude. Since New York is at about 41 N, that means it gets about 9.1 hours of daylight. If you started moving south at the crack of dawn at 100 mph, you could go ... | [
"The winter solstice for NY is the summer solstice for Antarctica."
] | [
"I haven't done any calculation. I am just trying to visualize it. ",
"To achieve what you are asking you basically want to flee faster as possible from the \"shade\" of the night incoming towards you (try to imagine the light/night cicle on a 3D earth).",
"The best flee ruote is traveling perpendicular to th... |
[
"Is the deep ocean floor littered with the bones of fish and mammals which have died over the years?"
] | [
false
] | [deleted] | [
"Do bones dissolve in the ocean, or do they sink to the bottom and stay there until something covers them up?",
"A bit of all of the above. Critters of all kinds die in the ocean, and their dead remains drift to the ocean floor. The descent to the bottom takes time and is usually measured in days, which gives bac... | [
"Phenomenal answer"
] | [
"Marble involves a completely different process, at most marginally related to the pelagic sedimentation I glossed over in the comment above.",
"What you need for the formation of marble is carbonate rocks. There are all kinds; some form in deep water environment and others not. Most are sedimentary, but a few ar... |
[
"How come Delta has been able to crowd out other strains of Covid inmost countries?"
] | [
false
] | Alpha used to be dominant in UK and now it's almost nonexistent there. Is that just due to delta's sheer transmissibility. I would think, since alpha is also quite transmissible it would still somewhat keep a foothold in most countries. | [
"The real population dynamics are pretty complex, but it really all comes back to the nature of exponential growth. If two variants have the same generation time, that is, the same time between a person initially becoming exposed and then becoming infectious and then either recovering or dying, even a relatively sm... | [
"To answer your question, I went to do a quick googling to find information about the transmissibility of Alpha and Delta variants. And it seems that the Delta variant is about 50% more contagious than the Alpha variant according to ",
"The Washington Post",
".",
"Furthermore, according to ",
"CDC",
", De... | [
"The missing piece may be either of",
"Once you recover from Delta, you have cross-immunity against Alpha, so the rapid spread of Delta leaves Alpha with few potential victims. Alpha may, so to speak, starve to death. (Not that viruses can starve, or indeed eat.)",
"If you are protecting yourself well enough ... |
[
"When swinging a baseball bat, tennis racquet, golf club, etc. why is \"follow through\" so crucial?"
] | [
false
] | Once that spit-second of contact has been made with the ball, why should any further motion (or lack thereof) make any difference at all? | [
"It did not go well."
] | [
"At the risk of sounding like a layman, I would tend to think that if you don't follow through and decide to stop at the point of impact, your body is going to start working to reduce your motion before you actually end up hitting the ball.",
"Thus, energy that could have gone into the ball is being squandered o... | [
"He didn't aim for the comment, he aimed at an imaginary spot below the comment."
] |
[
"Have their been any vaccines that were and still are safe for adults but not for children?"
] | [
false
] | With the current wait for the covid vaccines to get approved for children, has there ever been a vaccine that was and still is approved for adults but not for children? Or even where the adult dosage would be dangerous if given to children? | [
"There are two main concerns with giving vaccines to children:",
"Firstly whether the dose needs to be adjusted, either up or down to maximize immune response while minimizing side effects.",
"Secondly whether there are any new or unique safety issues with the vaccine in children. Children are not just \"smalle... | [
"The smallpox vaccine which used a live virus was not safe for infants under 1 year old. ",
"https://www.ph.ucla.edu/epi/bioter/smallpoxvacriskyeyes.html",
" (Article from 2003).",
"COVID vaccines are quite different from this, though."
] | [
"To expand on this, out of curiosity, what are some aspects in where their bodies work differently?"
] |
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