title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"During meiosis do chromasomes cross over only at specific points? For example is it possible to cut a gene in half during the crossing over?"
] | [
false
] | Eg. If 2 chromosomes crossed over and the gene for haemoglobin was split between the maternal and the paternal chromosome. Would this actually be possible or are there systems which prevent genes from being broken due to crossing over? I mean how likely is it that the gene will cross over right between the start and st... | [
"Crossovers definitely do occur within genes. As long as there is not a single nucleotide lost or added when this happens, then nothing is wrong. If such a thing occurs it is called an ",
" and is either an insertion or deletion of nucleotides within the gene. If this happens with one or two nucleotides it can ha... | [
"Incidentally, events called translocations can occur where part of one chromosome accidentally crosses over with its non-partner chromosome. In those cases, it's possible to fuse two genes, and a new \"fusion protein\" can be generated. (This is pretty rare, since translocations do not occur very often, and most r... | [
"Most mutations occur in S phase."
] |
[
"Why are the eyes of burn victims often left intact?"
] | [
false
] | [deleted] | [
"Eyes are covered and filled with fluid which is mostly water. Water has to absorb a lot of heat to increase in temperature as compared to most other materials. Because water can carry a large amount of heat, we use it in heating system and cooling system (like radiators).",
"Skin, muscles, and connective tissue ... | [
"And don't forget about the blinking reflect. Eyelids provide more protection than I think people give them credit for."
] | [
"I'm not sure they'd be terribly effective against large burns."
] |
[
"How were the elements formed after the big bang?"
] | [
false
] | null | [
"Hydrogen would be formed by electrons and protons forming pairs(via the electromagnetic force). Wikipedia seems to suggest there was enough energy for helium to be produced as well. ",
"http://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis",
"The rest of the elements would be produced by fusion in the core of ... | [
"Well it's easier to start the story from the Big Bang.",
"So after the universe cooled down enough protons and neutrons started coming together and you end up with a universe of 75% hydrogen and 25% helium and a minute amount of lithium. So all first generation stars started from this matter.",
"A star uses fu... | [
"As for non main sequence, there are a few more explosive events other than supernovae that are thought to produce the heavier elements. Classical Novae and X-ray bursts are the most prominent."
] |
[
"I think I have some really profound ignorance about how gravity works, please help."
] | [
false
] | Suppose a person is living in an orbital space station and has a long enough rope, the other end of the rope is on Earth. Could he just about as easily (excluding fatigue for now, the lenght of the operation) pull up say 5kg payload in a bucket from Earth onto the space station as doing the same on Earth from a well? C... | [
"1a. In order to put a thing in orbit, it has to be moving ",
" parallel to the surface of the Earth. Seventeen thousand miles an hour fast, for low-Earth orbit. The energy required to ",
" something from rest to that relative speed ",
" the energy required to lift that thing straight up into the sky."
] | [
"1a) I believe if you do it right, the energy for parallel acceleration is taken from the rotating Earth itself."
] | [
"Not nearly. If we fix our coordinate frame at the Earth's centre of rotation, such that a fixed point on the Earth's surface is moving around it in a circle, that point is moving only about a thousand miles an hour. You need ",
" to be in low Earth orbit.",
"It's true that it requires less energy to get to orb... |
[
"Distance, time and light (simple)"
] | [
false
] | [deleted] | [
"While moving the period should change a little as light have to travel a little farther when it starts again."
] | [
"While moving the period should change a little as light have to travel a little farther when it starts again."
] | [
"Well, that's not true. Light still travels the speed of light. If you move backwards, the blinking will be offset in time by d/c, where d is distance, c is speed of light.",
"The laser is sending out somewhere close to n photons/second, like a BB gun constantly shooting BBs. As you moved backwards, the wall woul... |
[
"Do we have any idea if ancient peoples had the sames types and rates of cancer that we experience now?"
] | [
false
] | null | [
"An old hypothesis, and partly true. Absolute lifespan for many pre-industrial lifespan was in many cases not significantly shorter than now, but average lifespan was much shorter due to infant mortality. There have been 80 and 100 year old folks for many centuries. There is also some evidence now that cancers have... | [
"An old hypothesis, and partly true. Absolute lifespan for many pre-industrial lifespan was in many cases not significantly shorter than now, but average lifespan was much shorter due to infant mortality. There have been 80 and 100 year old folks for many centuries. There is also some evidence now that cancers have... | [
"Source for sugar related studies?"
] |
[
"When a black hole is said to be spinning, does that refer to the accretion disk or can we actually make observations about the behavior of matter below the event horizon?"
] | [
false
] | null | [
"The \"spin\" of the black hole isn't about the accretion disk, no, nor really is it about the behavior of matter inside. It's a property of the black hole, but remember the matter inside isn't sitting around doing something - it can't be supported against gravitational collapse by any force in the universe (so spe... | [
"A black hole is the entire structure of the thing, including (hypothetical) singularity, event horizon, etc. The singularity, which if it exists (it does according to GR) is always within the event horizon, and yes it's described as a region of infinite density and zero volume. It's this \"structure\" that would b... | [
"Mathematically, isn't a black hole represented as a single, indefenetely small point? And a spinning black hole as a indefenetely thin ring?"
] |
[
"Shouldn't black holes exert the same gravitational force as an object of similar mass but lower density?"
] | [
false
] | null | [
"would be the same, wouldn't the gravitational force exerted by both the earth and the black hole on a far away object be the same?",
", and at the same distance, yes."
] | [
"For the region with r < R, where R is the radius of the Earth, the fields are different. There's no event horizon or singularity inside the Earth, the field just goes to zero at r = 0."
] | [
"For the region with r < R, where R is the radius of the Earth, the fields are different. There's no event horizon or singularity inside the Earth, the field just goes to zero at r = 0."
] |
[
"How do anti-depressants work? specifically in regards to treating social anxiety?"
] | [
false
] | null | [
"That's not accurate. If SSRIs blocked 5-HTRs, what receptors would serotonin activate?",
"SSRI stands for selective serotonin-reuptake inhibitor. They block the serotonin ",
" from recycling free-floating serotonin, thus extending their time spent in the synapse."
] | [
"Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed antidepressants for social anxiety disorder (SAD). As another person commented, SSRIs work by preventing a process called ",
". When neurotransmitters, like serotonin, are released by a neuron, they move into the synapse, a small sp... | [
"It depends on the type of anti depressant. SSRI’s (selective serotonin reuptake inhibitors) help regulate your Serotonin levels and increase them by binding to the same receptors that receive serotonin. This blocks the actual serotonin from binding to the receptors which leads to increase free floating serotonin."... |
[
"How do we know how many isotopes exist in the universe for an element, and their percentages, to determine the atomic mass? As we discover new isotopes, does a printed periodic table become obsolete because that element will have a new atomic mass?"
] | [
false
] | [deleted] | [
"There are 22 mononuclidic elements. The abundances of those don't change. Those are important for calibrating detectors and such.",
"For the rest, standard atomic weights are revised biennially by the IUPAC's ",
"Commission on Isotopic Abundances and Atomic Weights",
" (CIAAW). Should you ever have troubl... | [
"The percentages used aren't the percentages \"in the universe\", they're the percentages on Earth. And we know them because they can be measured.",
"If you take a bunch of natural chlorine, you can do mass spectrometry, for example, to determine the ratios of each isotope in the sample.",
"The numbers don't ne... | [
"I'm not a pedantic asshole",
"Well, you are, but that's okay. That's why we all come to reddit.",
"I'm guessing that there are probably less than 100 people in whatever country you in who even know about the CIAAW. Worth mentioning to your lecturers.",
"For more fun history, the CIAAW was created in 1899 t... |
[
"What exactly is itching?"
] | [
false
] | From a medical perspective what is the function of itching and what exactly is it? I mean in a way id as a layman say that it is the opposite of pain. Both have a function to let you know where to focus your attention on, on your body. Pain in a way asks you to stop doing what you'r doing and itch is asking you to do w... | [
"Itchiness is not a single phenomenon. There appear to be several different pathways that can cause itching. The best known one is the histamine response that antihistamines (benadryl, claritin, etc.) are good at blunting.",
"There seem to be other itch receptor pathways, though, and I'm not sure if anyone knows... | [
"Itchiness is not a single phenomenon. There appear to be several different pathways that can cause itching.",
"Here are some nice tables from a review on itchiness that show the pathways/mediators (",
"Table 1",
" and ",
"Table 2",
"). ",
"Also, while I'm making a comment, I thought I'd add that pain (... | [
"I asked a ",
"very similar question",
" almost two years to the day, ago. ",
"This other thread",
" the discussions in this thread, answered a lot of my questions and led me to \n",
".\nSorry, pointed you to wrong interesting article, ",
"here is the correct one",
"\n I hope it helps you. "
] |
[
"Why would melting ice caps raise sea levels?"
] | [
false
] | I always imagine an analogy with a glass of ice water filled to the brim. When the ice melts, the water doesn't spill over the edge. So why would melting ice caps raise sea levels? I feel like I'm leaving something out here, but I can't figure out what. Thanks | [
"The biggest icecaps are on top of land (Greenland and Antarctica)"
] | [
"Likewise, as large ice shelves break off of the Antarctic coast, glaciers that were being held back by them will begin to flow more quickly."
] | [
"Likewise, as large ice shelves break off of the Antarctic coast, glaciers that were being held back by them will begin to flow more quickly."
] |
[
"What are the chances the Voyager 1 Probe ends up in a black hole?"
] | [
false
] | null | [
"It's so unlikely that you have to get into weird distant future time before the chance even starts to get reasonable.",
"If you're floating through interstellar space, any time you approach a star or black hole, you are going faster than its escape velocity. Escape velocity tells you the amount of kinetic energy... | [
"Wow, thanks for sending me down a Wikipedia rabbit hole!"
] | [
"Space is so vast that even when the Andromeda Galaxy collides with ours, the chance of two stars actually colliding is extremely low, despite there being billions of stars in each Galaxy."
] |
[
"Do humans ever actually die purely of old age or is there always some underlying disease that may have been caused by old age?"
] | [
false
] | null | [
"This is an interesting question. Believe it or not until recently people were not interested in the cause of death in the extremely old. Focus was (and is) on causes of death in the younger people. Consequently it was extremely rare for a person who \"died of old age\" as it were to have an autopsy performed.",
... | [
"Also, as an aside, cells undergo mitosis until they become pre-cancerous or their telomeres are too degraded and then they senesce i.e. stop dividing. In one case, an extremely old woman had her immune cells (B-cells I believe, but I may be wrong) sequenced and it was found that all her immune cells came from two ... | [
"some of that is addressed in the main body of the article:",
"Sixty percent (n ¼ 24) of the deceased were described by\ntheir family or their family physician as having been healthy\nat the time of death. However, 58% had cardiac antecedents\nsuch as chronic heart failure, stable angina pectoris, a history\nof m... |
[
"What happens to the donors genetic code after a blood transfusion?"
] | [
false
] | So I donated blood the other day and it got me thinking. what happens to my DNA after the blood is used? Does that person now carry a little bit of identifiable ME for a little while? And if so for how long? | [
"Erythrocytes don't have DNA! They need all the space they can get for hemoglobin, so right before it is fully mature it packages up its nucleus (where the majority of the DNA is), and ejects it. This package also contains the organelles, including the mitochondria which also have their own DNA. ",
"The good thin... | [
"Very cool. Thanks for the response!"
] | [
"One kind of interesting note on this is the matter of antigens. The body can still recognize it's own cells (or at least it's own type) by the antigen receptors on the cell's membrane. This may sound complicated, but you've probably heard it dozens of times as type A, B, AB, and O blood types. The antigen receptor... |
[
"This graph appears to show a decline in measles cases prior to the introduction of the measles vaccine. Why is that?"
] | [
false
] | null | [
"The graph doesn't really show a reduction, rather a 'boom and bust' cycle with a reduction in amplitude in the last couple of phases.",
"This is neatly explained by the other comments to a greater or lesser degree.",
"But when reading graphs of this sort you must read all that is shown and understand the limit... | [
"Because the immune system of adults is 'too powerful'; it ",
" to pathogens such as measles, and the immune reaction can cause a whole scala of interesting symptoms that are potentially more damaging than the pathogen itself."
] | [
"Immunologist here! These different terms can be super confusing in the best of cases! Just to clarify in this instance:"
] |
[
"How did the dinosaurs gain traits to go from cold-blooded to warm-blooded when tgey evolved into the ancestors of modern birds? Or did the ancestors of modern birds turn warm-blooded after feathers covered the entire body?"
] | [
false
] | null | [
"Warm bloodedness is largely a function of metabolism. It has to do with a variety of physiological and chemical processes in the body.",
"It's also kind of a spectrum. larger birds are better at maintaining body temp than smaller birds. Small mammals like bats and some hibernating rodents go into torpor because... | [
"Bluefin tuna generate enormous amounts of heat when pursuing prey, and have ",
"complicated heat exchange systems",
" to keep this heat from being lost through their gills. They're sort of warm blooded on demand. Sharks don't do any of that, but the large ones have enough metabolic activity to be consistently ... | [
"Just FYI there is much debate whether dinsoaurs were warm or cold blooded, or something in between. ",
"See here",
" for example. Some dinosaurs, such as the ancestors of birds were probably warm-blooded. Those that were fully feathered were almost certainly warm-blooded"
] |
[
"Why is angular momentum so important in studying the atom? Are atoms subject to gyroscopic precession?"
] | [
false
] | I'm starting a quantum mechanics course at university. I want to know why angular momentum is so important ? Many Thanks | [
"Because angular momentum is a conserved quantity, meaning the total angular momentum operator commutes with the Hamiltonian of the system. So it's a quantum number which can be used to label your energy eigenstates.",
"And that's ultimately what you're trying to do when studying bound quantum systems: find and c... | [
"To add to this in a slightly more ELI5 style: quantum mechanics leads to the discretization of the orbital angular momentum of electrons that are bound to atomic nuclei. This, in turn, leads to the different orbitals that electrons can occupy. This, in turn, leads to the ways in which atoms form different bonds ... | [
"The electrons rotate around the nucleus, so clearly they have angular moment. ",
"The reason why it is important is because the electric force between the proton and electron is spherically symmetric, meaning that the proton cannot change the angular momentum of an electron through electric force.",
"Recall ho... |
[
"Why do whales beach themselves?"
] | [
false
] | [deleted] | [
"Here's an article that discusses it: ",
"http://www.scientificamerican.com/article.cfm?id=why-do-whales-beach-themselves",
"TL;DR - In most cases it is due to injury or illness - in some cases they just don't know",
"EDIT: this Wikipedia article also discusses some of the thought to be causes: ",
"http://... | [
"Military sonar has been implicated in some cases but whales were beaching themselves long before sonar was invented: ",
"photo of whale stranding, 1902",
"16th century dutch engravings",
"beached whales, 1577"
] | [
"Military sonar has been blamed pretty successfully.",
" ",
"However, courts ruled that national security trumps everything. "
] |
[
"If the Oxford vaccine targets Covid-19's protein spike and the Moderna vaccine targets its RNA, theoretically could we get more protection by getting both vaccines?"
] | [
false
] | If they target different aspects of the virus, does that mean that getting a one shot after the other wouldn't be redundant? | [
"They both target spike. Moderna works differently. Moderna uses mRNA as the delivery mechanism of the vaccine. Our body then turns that mRNA into a protein that the immune system recognizes and creates antibodies to. ",
"So essentially the end product our immune system sees is similar, it’s just how the vaccine ... | [
"We don’t ",
" ",
". It is probably not a good idea. ",
", The second dose of ",
" the ",
" COVID vaccine had more severe reactions than the first dose. ",
"However, and most importantly, we don’t have data on ",
" ",
", so no one can tell you it has been proven safe. It might not kill you, but for ... | [
"Is there likely to be a danger of taking more than one? Lets say you grab whatever comes first, then a few months later it turns out the next one offers better protection."
] |
[
"Are mosquitos good for anything at all?"
] | [
false
] | I was always told that everything in the animal world had a purpose. Are mosquitos just good for nothing? If they are useless, why haven’t we killed them off by now to prevent all the disease they give? | [
"Hi there! I work with mosquitoes right now for my research and I get this question a lot from curious folks. First, thinking that an animal needs to be \"good for something\" is not how we should view another living thing. Animals and plants evolved to suit their environment, they are very good at that though it m... | [
"Very well placed, and in layman’s terms. Thank you for the well thought out response. ",
"I did not know they drank nectar at all! You have shed a new light on them. I would still get the skeeves if one was crawling on me, but I respect them greater from a distance now.",
"If you have time to spare in your day... | [
"Thank you for reading my longwinded response! I very much understand getting the skeeves and I don't blame anyone for that response. I used to work in a lab where we had an ",
" colony. They frequently got loose and would bite me all day. I now have an allergy to this species' bites, I get huge welts. So I get h... |
[
"I keep reading about how Covid has had a worse effect on minorities in the US particularly blacks. Is this all because of environmental/societal reasons, or do people of African decent actually have a harder time with the virus physically?"
] | [
false
] | [deleted] | [
"There are a variety of factors involved.",
"In the case of kidney failure due to COVID-19, many people of African descent are more susceptible due to variants in the APOL1 gene. This isn't specific to COVID-19 though, the variants just make the kidneys weaker in general. Source: ",
"https://jasn.asnjournals.or... | [
"https://www.mayoclinic.org/diseases-conditions/coronavirus/expert-answers/coronavirus-infection-by-race/faq-20488802",
"\"While there's no evidence that people of color have genetic or other biological factors that make them more likely to be affected by COVID-19, they are more likely to have underlying health c... | [
"Excellent answer, one addition is that air pollution leads to worse covid outcomes, and in the US, air pollution is correlated with low income areas (denser, more industrial pollution, etc)"
] |
[
"I there a maximum strength for a permanent magnet of a given mass?"
] | [
false
] | Pretty straight forward. If we held a 1 gram "blank" neodymium magnet to a junk yard electromagnet and another to a magnetar (magnetic neutron star), they should both become just as powerful, right? What limits the power they can achieve? | [
"The maximum \"strength\" of a permanent magnet is when the magnet is a single ",
"magnetic domain",
". You can think of a permanent magnet as a collection of many atom-sized magnets all pointing in generally the same direction. When they are all perfectly aligned, the magnetic field sufficiently far away from ... | [
"Well for an absolute top bound, you could start with the elementary particle with highest spin-to-mass ratio (I guess a neutrino, whichever is bounded to be the lightest). Then you divide the 'given mass' of your magnet, for example one gram, by the neutrino mass. You'll get the number of neutrinos present, e.g. t... | [
"Indeed. And the saturation magnetization of iron-based alloys is around 2 tesla. But that is in the lab where electrons are behaving normally; a magnetar is a different beast."
] |
[
"If an ant was the same size as a tiger, would still be able to lift 20 times its own weight?"
] | [
false
] | null | [
"No. The problem starts when you scale up the length and all other measurements in equal proportion, then your volume (i.e. mass) grows with the third power of that length, while the strength of your bones and muscles, which depend on their cross section, only grow as the square of that length. An ant the size of ... | [
"Also Ants breath thorugh holes in their body and they would suffocate when they were as big as tigers."
] | [
"Although millions of years ago there were much bigger bugs (not quite tiger sized, but huge for bugs) that were able to survive while breathing through sphericals, but the atmosphere had a much higher percentage of oxygen then."
] |
[
"[Medicine] What steps are taken to diagnosis a cell as cancerous ?"
] | [
false
] | I know preventive scanning is big deal due to the earlier one is diagnosed, usually the better the outcome (depends on stage, etc.), but when diagnosed with a possible cancerous tumor, what steps do you take to verify? | [
"Just to clarify further upon what's been said:",
"A pathologist will usually get the sample from a biopsy. They will prepare it onto a film and have a look at it under the microscope. Because cancers are rapid, uncontrolled growth of cells, they tend to look different to normal cells. Very basic things to look f... | [
"As mentioned by others, the diagnosis is typically based on visual inspection: either of biopsied cells under a microscope, or of a tumor or the progression of a tumor visualized by medical imaging technologies.",
"It's a situation where a trained observer would know it when they see it, but the question of how ... | [
"There are also biochemical markers of cancer that can be detected in the cell in a variety of ways. For example our lab works a lot with the ",
"epidermal growth factor receptor",
", which is upregulated in several cancers. However, these are more experimental techniques. As _Momotsuki explained, having a p... |
[
"If you had a CPU made from room-temperature superconducting material, could you overclock it infinitely fast?"
] | [
false
] | And would speed increase scale 1:1 with increased power forever? Would a room-temperature s.c. be the end of moore's law? | [
"My Background: Perkee is my name, Computer Engineering is my game. The conductors aren't of major concern. What you care more about is the switching speed of the logic gates in the computer. Logic gates are made out of transistors, which have to saturate/desaturate a semiconductor with electrons before it changes ... | [
"In addition to this, to switch each transistor at infinitely speed would take an infinite amount of current which is impossible in and of itself. Also superconductors have a breakdown current density that if they surpass, they gain resistance and thus quit being superconductors. So even if one was able to make a s... | [
"Actually one of the main speed limiting mechanisms in semiconductor logic is the RC charge time. Granted you can't have both a semiconductor AND a superconductor at the same time, so you'll always have some resistance. But if you allow disruptive technologies, superconducting logic has the potential for very high ... |
[
"Why don't people have different natural hair colors like blue or green?"
] | [
false
] | Are there any natural hair colors besides red, black, brown, and blonde? | [
"Mammals main source of coloring is melanin, which produces browns, blacks and shade of tan. Other animals such as birds have multiple types of pigment along with melanin including, carotenoids which produce red, orange or yellow feathers. Also Porphyrins, an amino acid that can produce red, brown, pink and green... | [
"We already eat many of the same foods that birds eat. Flamingos get their pink color from carotenoids in crustaceans like shrimp. The pigment is then deposited in the feathers which shows up well because the feathers start off white. No mammals to my knowledge have developed the means of converting these additio... | [
"Humans simply do not produce pigments which are blue or green. Irises appear blue or green in a similar way the sky appears blue, not due to pigments. If you ground up an iris, it would no longer appear the same color.",
"The main pigment we have is melanin, which serves an important evolutionary purpose in prod... |
[
"Why is it that when you rub your eyes you start seeing weird colours and patterns?"
] | [
false
] | null | [
"The act of rubbing applies a mechanical pressure on your eyes. This can cause some of your sensory cells to activate, and it will temporarily deform your retina. Because the sensory cells in your eye are typically only activated by light, and because the only signal they can send to the brain upon activation is \"... | [
"Is it harmful? The retina deformation/manual activation, I mean, as opposed to activation by light."
] | [
"Does the dark blob at the top of your vision appear at the top because your brain flips the image your eye \"captures\"?"
] |
[
"Is the phase of AC over a very long wire the same at both ends?"
] | [
false
] | If you have a wire that is very long (100s of km) and you put an AC current over that wire, will the phase of the AC at both ends be the same? Considering that there is a delay between the current moving from one end to the other. | [
"If the wavelength of the current becomes small compared with the physical size of the wire, you have to start treating it like a ",
"transmission line",
".",
"When you manipulate Maxwell’s equations inside the transmission line, you get a set of wave equations for the voltage and current called the ",
"Tel... | [
"Let me expand on this a little, since the \"100's of km\" in your question struck me as related to power transmission (50 Hz or 60 Hz power for example), and because phase must be measured relative to something, and we should clarify that (otherwise @RobusEtCeleritas is correct on phase relative to ground).",
"I... | [
"Let me get a little more precise with the wording: In power systems there are Neutrals and Grounds (or Earths as some in Europe call it). Technically, Neutral is the 'return' path for the power that completes the circuit, while Ground is physically attached to ground (in your house there is a copper-clad rod driv... |
[
"Is a snake's digestive track in one direction?"
] | [
false
] | Hello. I was having a discussion with a friend about snakes and how they go about digesting their food. We kept using the frame of reference that food goes in through our mouths, then through the digestive tracks of the stomach, then eventually out. We figured snakes were the same way, except their digestive tracks are... | [
"I don’t know about discomfort, but I can add that after a large meal, snakes often go into an extended period of low activity.\nSo, yeah, they don’t like to move around a lot with a full belly, either."
] | [
"When snakes eat something really big, it just kind of sits in there for a long time. You can actually see this from the outside of the snake, and the whole body of the snake expands to account for large objects."
] | [
"Ah good point! So it just sits there in their body slowly disintegrating? Is it comfortable for the snake to do it like that? I just imagine me being bloated from a meal, the last thing I’m thinking is “let’s go move around” lol. Maybe snakes are the same way?"
] |
[
"If there are no, or minimal resistance, as in space, what are the limiting factors to the \"top\" speed of a certain propulsion system?"
] | [
false
] | Just read the article on the new plasma engine and was wondering what factors limit the top speed to 35 miles an hour. If there are no, or minimal resistance, as in space, what are the limiting factor to the "top" speed with a certain propulsion system? | [
"First off, ",
" ",
" is 35 miles ",
". As far as I know, the only physical \"speed limit\" in space (you simply can not go any faster than this) is the speed of light... Up to that point, as long as you keep adding thrust, you keep accelerating. Take the Ion Drive for example, it's not a hugely powerful eng... | [
"In the most simplistic model, kinda, but in reality it depends on your destination. If your destination is moving with respect to you, you'll be using something like a Hohmann transfer. If you're going somewhere with an atmosphere, you can aerobrake on arrival. If you're going someplace with moons, you can use t... | [
"Assuming you want to stop at the end of your trip, and not just continue indefinitely, wouldn't it follow that you can only use ~half your fuel to accelerate, as you'll require the same amount of fuel to decelerate at the other end?"
] |
[
"Does E = mc^2 imply special relativity?"
] | [
false
] | null | [
"could there be other ways like the “ether” that are also compatible with E=mc",
"?",
"Yep. You're correct. You can violate special relativity and still have this"
] | [
"I mean you would still get heavier and heavier as you sped up",
"Relativistic mass in this sense is a bit of an outmoded concept. It is much more useful to think of mass as the rest energy/c",
". So in relativity you have",
"E",
" = m",
"c",
" + p",
"c",
"where p is the momentum. You can have non-r... | [
"Can you expand on how exactly you could violate special relativity? I mean you would still get heavier and heavier as you sped up, so it looks a lot like special relativity"
] |
[
"Let's say i'd like to have a balloon 100km up in the air. What would be the ideal mix of gas inside the balloon?"
] | [
false
] | 100% helium? | [
"Hydrogen.",
"The density of air at 100km is only 0.5 milligrams per cubic metre.",
"Hydrogen would be 0.035 mg/m",
" and helium 0.07 mg/m",
" .",
"If you had a hydrogen balloon of 200,000 m",
" , you could use it to lift a small apple. (But only if the fabric of the balloon was weightless.)"
] | [
"With ultra-light 3.4µm polyethylene fabric, you'd need a balloon nearly 20km in radius in order for it to contain enough gas to lift its own weight at 100km altitude."
] | [
"Thank you so much for this. (a little bit late but never too late)"
] |
[
"What is the definition of death? How long can someone be 'dead' and be 'brought back to life'?"
] | [
false
] | I ask because of the recent tragedies with footballers collapsing mid-game. It's being reported that Fabrice Muamba was dead for 78 minutes, 48 mins from collapse to hospital and a further 30 minutes after. He has now, a few weeks later, been discharged from hospital. My understanding was that death is the point where ... | [
"I don't think you're really asking what the 'definition of death' is. You're asking why some people survive ischemic insults that other's do not, or what treatments can prevent ischemic brain injury.",
"There is a lot of treatment using ",
"hypothermic protocol",
" to protect the brain in the event of a car... | [
"The heart does not need to stop for brain death to occur, if your tissue cannot absorb oxygen or if your MAP(Mean arterial pressure) is below 30mmHg then the brain is not perfused.",
"Brain damage (which implies death of neurons) post cardiac arrest has many mitigating factors. Some cells can die within minutes... | [
"Shocks with a defibrillator are attempts to restore normal heart rhythm, they do not circulate any blood. It seems like your posts implies this, though I'm sure you didn't mean that.",
"The purpose of CPR is to keep the brain, heart and lungs perfused and oxygenated until the body can resume these functions on ... |
[
"Why is it faster to recharge batteries from 0-50% than from 50-100%?"
] | [
false
] | null | [
"It's basically like inflating a tire: when it's empty it doesn't take a lot of force to add air to it, and as it fills up more and more force is needed to add the same amount of air to it.",
"Batteries are similar, so the more energy they already contain, the harder it gets to add more. "
] | [
"The fact that the tire is leaky is a separate concern. The issue is that the fuller the tire gets, the harder it is to pump air into it. If you've ever pumped a baseball or something similar, you probably noticed that you slow down as you get towards the end because it get harder and harder to push on the pump to ... | [
"The fact that the tire is leaky is a separate concern. The issue is that the fuller the tire gets, the harder it is to pump air into it. If you've ever pumped a baseball or something similar, you probably noticed that you slow down as you get towards the end because it get harder and harder to push on the pump to ... |
[
"Can someone explain what exactly a \"neutron beam\" is?"
] | [
false
] | Inspired by . What exactly would cause such a beam to occur? Does it pose a threat to humans? Are there any other dangers of this occurring outside of a contained environment? | [
"to me it sounds like a mistranslation of what we'd call neutron emission. But I'm not a nuclear engineer, so I could be quite wrong."
] | [
"What shavera said. But on a sidenote, we can indeed create neutron beams with particle accelerators. These beams of neutrons are often used to study properties of materials."
] | [
"Neutron beams pretty much wouldn't be visible until they hit something.",
"This isn't that surprising, though - lasers are the same way. If you see a laser from the side, it is being scattered by dust/air."
] |
[
"If one section of an interferometer is orders of magnitude longer than the other, will there still be interference between the particles/beams?"
] | [
false
] | , B1 and B2 are beam splitters, M are mirrors, the interferometer is calibrated so that detector D1 will always detect the photon, and detector D2 will never detect the photon because of destructive interference. With the classical interpretation, interference happens between the light waves as they travel through the ... | [
"they are all shorter than the coherence length.",
"They don't have to all be shorter than the coherence length. Unless the beams pass through a turbulent medium or something that disturbs the phase, you only need the difference of the path lengths to be less than the coherence length to be able to observe interf... | [
"Almost definitely not. \nThe source emitting the light will only be coherent up to a certain point- the ",
"coherence length",
". ",
"Bearing in mind that even the coherence of ",
"laser light",
" will drift over time. This happens for every source, it just happens that lasers are the easiest to deal wi... | [
"it's not so outragous to think of an observational set-up with a very nice hydrogen maser, one of the mirrors is a corner cube reflector on the moon, and the other is in the same terrestrial building as the maser itself,",
"That only works if the coherence length of the maser is greater than twice the distance t... |
[
"What percentage of a computer's power consumption ends up as heat? Is a computer an efficient heater?"
] | [
false
] | As we know, computers convert electrical energy into heat energy. But do they convert all of it that way? I suppose some of the current ends up as electrical signals to monitors and peripherals. But what about the rest? | [
"Roughly all of it. Household appliances (except special cases like heat exchangers) will end up converting all the electricity they pull from the grid into heat.",
"The difference is that some (like computers) will do something useful like computing things by switching electronic gates on and off very quickly. O... | [
"I suppose some of the current ends up as electrical signals to monitors and peripherals.",
"They have negligible power (unless you charge some other object via USB or similar) and this power is typically dissipated in the peripherals then. Charging a phone and then taking the phone away is an option to convert l... | [
"It either goes back to the grid or comes out as heat, eventually. Which means they are just as efficient as an electric heater in that regard. ",
"They're less efficient in that they lack proper radiators to direct the heat to you, and running them at full power can damage expensive components, which doesn't hap... |
[
"Ask Anything Wednesday - Economics, Political Science, Linguistics, Anthropology"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! ... | [
"This kind of fear has been around since the 1700s when the loom was invented, and has never proven to be true. Machines have created more jobs than they destroyed since their inception, it's just the nature of employment that has changed over time."
] | [
"Linguistics: Why does Australia (seem to) have less linguistic variation internally than the USA? Is it because Australia is younger, or has fewer people, or is it because of a different initial mix of people? "
] | [
"If you mean a society that works solely on plastic, then yeah definitely. ",
"Money has value in our society today because we think it does. Technically it's called fiat money, which means it's not backed by any commodity, such as gold.",
"The first banknotes were commodity backed in the sense that you could r... |
[
"How does higher temperature lead to less rainfall?"
] | [
false
] | In wake of the CA forest fires lots of people are talking about how climate change is to blame. This doesn't make sense to me (or generally the desertification fears of climate change). I understand that at a higher temperature water on the ground will evaporate faster (but it seems like at a temp change that's very lo... | [
"Hi G0DatWork thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the follo... | [
"Warmer air holds more water. The air itself holds it. That’s why relative humidity is a thing. 50% humidity at 5c will feel dryer than 50% humidity at 30c. The air at 5c can only store x amount before it is full, that same air at 30c can hold way way more than said x amount. "
] | [
"So the increase in water saturation as a gas at a temp change of 1C is more than the amount of water that evaporates? "
] |
[
"Is there a \"Reynold's number\" for electricity?"
] | [
false
] | Is electrical transmission in wires somewhat analogous to fluid flow through pipes? | [
"Electrical transmission in pipes is somewhat analogous in the sense that if you look at the equations that describe pipe flow with no viscosity or boundary layer effects, those equations are exactly the same as the equations for electrical transmission in a line. ",
"However, when you add viscosity and boundary ... | [
"Is electrical transmission in wires somewhat analogous to fluid flow through pipes?",
"Very loosely. The conservation equations do end up taking rather similar forms.",
"Is there a \"Reynold's number\" for electricity?",
"Reynolds number is just one important non-dimensional parameter in the Navier-Stokes eq... | [
"This quantity is actually referred to as the \"Quality Factor\" or \"Q\" of an inductor, interestingly enough...",
"Edit: Also, the dielectric constant of a material in it's full form includes an imaginary part which corresponds to loss... I think the ratio of the real and imaginary parts of the dielectric const... |
[
"What's the difference between Gravitational lens and Gravitational waves?"
] | [
false
] | I was watching a video where they talked about using quantum computers to prove gravitational lens in simulation but now I hear about gravitational waves. These concepts go over my head, looking to be taught what these are and if they're related in simple enough terms. I could also just not know enough to ask the que... | [
"They are two complete different effects, although both stem from general relativity, our best understanding of gravity.",
"Gravitational lensing occurs when you have a mass, and due to its gravitational field -- which is basically static -- light passing by that mass is deflected. When light is deflected this w... | [
"Gravitational lensing is usually seen when a massive galaxy or group of galaxies is between us and something we want to see. ",
"Berkeley got a ",
" example",
" of this just last year. The link shows the same supernova on four sides of a galaxy that is much closer to us. Think of holding up a wineglass in ... | [
"Gravitational lensing is due to a static unchanging gravitational field, whereas as gravitational wave is how a ",
" in the gravitational field propagates."
] |
[
"Does anyone know anything on Human Cytomegalovirus HCMV?"
] | [
false
] | I was wondering what changes (through genetic engineering) would be necessary to make Human Cytomegalovirus (HCMV): a) more virulent/communicable b) more severe (i.e cause sterilization in humans) Any thoughts? | [
"Why? Are you ",
"thinking of this?"
] | [
"Is that the virus they use in the movie? haha never saw it...",
"I'm thinking about the pros/cons of genetic engineering.."
] | [
"That would be ",
"here",
". There is very specific moral questions and ethical concerns with this."
] |
[
"[mechanical engineering/planatery] why is 3 km/s considered as hypervelocity?"
] | [
false
] | wouldn't it be more accurate to describe it as hypersonic? afte rall in space we have hypervelocity objects flying closer to a few of kilometers per second which does make the hypervelocity limit on earth seem a bit too low to coin it as such | [
"I think the Wikipedia article actually describes it pretty well. It is the point where structural materials such as metals behave more as a fluid on impact than a solid/metal. Hypervelocity contains a pretty wide range of velocities ranging from a few km/s to tens of thousands of km/s."
] | [
"The meaning also depends on context.",
"To an astrophysicist, a hypervelocity star is one that is traveling too fast to stay gravitationally bound to its parent galaxy. It is believed that these exceptional stars and planets were boosted beyond escape velocity by ",
"rather rare circumstances",
" involving a... | [
"It's not part of the definition of hypervelocity, but 3 km/s is also about the point that an object's kinetic energy is equal to the explosive power of an equivalent mass of TNT. When you're hitting an object that fast, it's similar to setting off a bomb."
] |
[
"Is it possible to weaponise a placebo?"
] | [
false
] | I was wondering if you made a harmless gas that looked, smelled, and sounded like, say, mustard gas, would that incapacitate soldiers who didn't have gas masks? | [
"Well, for a placebo effect to work, you need to convince someone that they should be effected in some way. But you're not going to get any effect just because you tell someone they should. For something like mustard gas, you would know if you had been exposed. After a minute of no obvious effect, people will figur... | [
"Well... What gas are you using? Is it in an enclosed space? Is it denser than air? What doesn't mustard gas smell like? Would soldiers know what it smells like? ",
"Remember that any gas still displaces air. If it does this at a fast rate it can be dangerous. Liquid nitrogen is dangerous because it displaces air... | [
"It's not impossible. Mass conversion disorders are physical disorders that have a psychological cause. The weirdest one I ever heard about was mass temporary blindness. Basically, you get enough people in a place to experience a symptom and the belief can spread. Sometimes you see it with something like seizur... |
[
"What the primary cause of the median income benefit from attending a 4 year university?"
] | [
false
] | I know the median college grad in the US earns over a million more dollars in their lifetime than the median high school grad. Is this entirely due to the benefits of the degree, or is there a statistical bias? It seems that many people I know who earn a degree don't use it at all, but do well in an unrelated field. If... | [
"Right so there are two questions you're asking here. One is:what is the effect of a 4 year university degree on earnings, all else the same? The second question is a statistical question: what is a statistical bias of a parameter and how does it apply here? ",
"Ok So lets begin. ",
" To first answer your qu... | [
"Ok. I wrote that at 2 am and kinda left out some of the big links. ",
"Borjas wrote one of the better/best text books on labor economics. ",
"This is a slideshow",
" of some basics on human capital development that I think he put out. Either way the information provides a basic breakdown of a earnings as... | [
"Thank you for the great write up. I read the links you provided, and they provide good background on the total difference, but they didn't provide any background on what those differences came from.",
"Honestly, I'd rather not papers on the subject, as I read enough papers in my day to day job. I am quite famili... |
[
"If you looked into a box with mirrors in the interior..."
] | [
false
] | [deleted] | [
"If the two way mirror was \"perfect\" you would not be able to see anything inside of the box because there wouldn't be a light source."
] | [
"Theoretically perfect mirrors would just keep the light bouncing around inside the box forever. You wouldn't see anything in that case, because the box would be opaque.",
"It makes sense if you think about what happens to a photon in the box. It'll travel in some direction, and hit a wall, and then there are onl... | [
"What it you closed the two-way mirror on the box, trapping light in it. What would you actually see?"
] |
[
"Can the Tetris effect include sounds too?"
] | [
false
] | The Tetris effect is when a person looks at a pattern so much that when he or she closes his or her eyes, the pattern can still be seen. So if a person heard a repeating noise enough does the same thing happen? Furthermore, why does the Tetris effect happen? | [
"I was actually going to bring up pokemon. I'd love to see some actual studies verifying it though."
] | [
"I was actually going to bring up pokemon. I'd love to see some actual studies verifying it though."
] | [
"I remember reading an article on something similar to what you're describing, however it was only looking at the phenomenon after long exposure to games. They coined it ",
"game transfer phenomena",
", wherein you hear sounds from video games after you stopped playing. There doesn't seem much about it online, ... |
[
"Why is the set of real numbers between 0 and 1 uncountable, but not the set of all integers?"
] | [
false
] | The answer that I have found elsewhere is that the integers can be listed as such 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13... and that the same cannot be done for the real numbers between 0 and 1. I don't see why this is true because I can list them as follows. 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.01, ... | [
"I don't see why this is true because I can list them as follows. ",
"0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.01, 0.11, 0.21, 0.31... ",
"This enumeration will never reach any real number that has a non-terminating decimal expansion. For example, 1/3 or 0.333...(repeating).",
"But you can also do th... | [
"You do not have ",
" irrational number in your list. You don't even cover all rational numbers, although that is possible with different approaches."
] | [
"An underappreciated property of countable infinity is that every element is finitely reachable. There's an infinite number of elements, but by virtue of being able to list them out, each of the infinite number of elements is at a finite index value. In principle you can \"reach\" any element of an infinite countab... |
[
"Oceanography - help is much appreciated!"
] | [
false
] | Hello AskScience. I am in the midst of writing a paper for my Oceanography class, and I have hit a slump in terms of sources for my topic. I chose to write my paper on the effects of natural disasters (such as the March earthquake in Japan or Haitian quake) on sea life/ecology, and am running aground (pun intended). If... | [
"Are you aware of google scholar? It's an excellent tool.",
"For example, I used it to find this"
] | [
"Google Scholar"
] | [
"Try Google Scholar as mentioned, and make sure to try many different keywords. If you are in college, go to your library and ask your librarian which databases you have access to. You could try databases like \"Fish, Fisheries & Aquatic Biodiversity Worldwide\". For example searching for \"tsunami\" gives you 1220... |
[
"Why are vaccinations only effective if everyone in a population is vaccinated?"
] | [
false
] | There's a pertussis outbreak where I live due to a small group of people who don't vaccinate their children. Many of the cases involve kids who were previously vaccinated against pertussis. Why will people catch diseases that they're vaccinated against? What type of exposure does a vaccination protect against? | [
"The vaccine for whooping cough (to use your example) is about 85% effective, and this is because people's immune systems do not always develop a perfect immune response to a vaccine. ",
"Let's consider a boring person's life. Let's say this guy goes from home to work, and only ever sees the people he works wit... | [
"Not to say there is anything wrong with this explanation (because there isn't), but here's another, slightly more abstract way of explaining it. When someone gets sick, they'll pass the virus on to their friends and coworkers, and those people will pass it on to ",
" friends and coworkers, and so on. The key que... | [
"To be fair, from a medical perspective, the importance of ",
"herd immunity",
" is also about protecting the immune-deficient, elderly, vaccine non-responders and the unvaccinated (including children before the age of vaccination)."
] |
[
"Why not 1024bit encryption or beyond?"
] | [
false
] | null | [
"512 bit encryption gives you about 10",
" possible keys. If you took every single atom in the known universe and somehow turned every single one of them into the fastest supercomputer ever build, it would still take an unimaginable many times the age of the universe to try all possibilities. While quantum comput... | [
"Careful, you're mixing up symmetric and public key encryption. In symmetric crypto, the key space is fully usable, meaning you really do have 10",
" available keys. RSA on the other hand uses large prime numbers, so there are a lot of holes in the space. That's why you see 4096 bit keys in RSA and 256 bit keys i... | [
"Please correct me if I'm mistaken, but my understanding was that a classical 512-bit encryption key that could be deciphered by a quantum algorithm would require only 512 qubits to do so."
] |
[
"How easy / difficult is it to *NOT* catch an illness in a pandemic situation?"
] | [
false
] | Let's say some lethal mutation of the flu virus goes pandemic in a worst-case scenario situation. Would my germaphobic habits give me a reasonably good shot at survival? I guess it just seems that most people catch viruses from unhealthy or at least germ-friendly habits. Or from their kids. Sure there's the unlucky po... | [
"It depends really. If the virus/illness/what-have-you is air or waterborne, it can be difficult to avoid until it's too late. If it's a person-to-person kind of illness, it can be a bit easier to avoid, and I think the habits you've developed as a germ-phobic person may make this kind of \"pandemic\" easier to avo... | [
"I realized about 90% of the way through that my statement sounded a lot like the game Pandemic (which wasn't intentional), so I threw the Madagascar thing in as a half-joke.",
"Truthfully it might still work out though; since the island has a pretty crappy travel infrastructure overall (thus making it difficult ... | [
"Wait, are you serious about Madagascar, or are you just referring to the games Pandemic?",
"Edit: Sorry if this isn't science related but I'm just curious."
] |
[
"Are there solar systems of stars, where a supermassive star has a group of smaller stars revolving around it?"
] | [
false
] | null | [
"Even large stars don't have ridiculous masses, so all of the stars end up orbiting each other, so it won't be quite like a solar system with one in the middle. One of the largest and heaviest stars is UY Scuti, its about 1,700x as large as the sun, but only about 32x heavier so if you put it and the the sun in a ... | [
"UY Scuti is one of the largest known, but nowhere close to being the most massive. The heaviest ones are well over 100 solar masses, with ",
"R136a1",
" clocking in at a whopping 265 times the mass of the Sun."
] | [
"Yes, they are called binary stars. They make up roughly 1/3 the number of stars in our galaxy. Although you if you mean more than 2 stars that's rare but there are a few potentials. If you are willing to be loose with the definition of a star, the current theory is that every galaxy has a super massive black hole ... |
[
"Why is personality an inheritable trait in dogs?"
] | [
false
] | Is personality reinforced over generations of breeding? | [
"The same reasons personality is fairly heritable in humans."
] | [
"The only guarantee is that your kids won't find either of you funny. ;) (sideways glance at etiquette bar)"
] | [
"Though it doesn't answer the entire question, ",
"Brunner's Syndrome",
" is a nice example of a clear link between genetics and personality in humans. In Brunner's a mutatation of the MAOA gene for the MAOA (monoamine oxidase A), which is responsible for breaking down lots of brain neurotransmitters, stops the... |
[
"Could it ever be possible to invent a bionic eye that allows people to see light outside of the visible spectrum, such as ultraviolet or infrared?"
] | [
false
] | null | [
"Your brain could probably handle the input anyway, experiments have shown that mice and new world monkeys are capable of comprehending the difference between red and green after having their natural red-green colorblindness fixed by gene therapy."
] | [
"There is a crappy first link from a little googling, but I recall some people getting their lenses replaced with ones that transmit UV. Normal lenses in our eyes absorb UV (hence the cataracts), and some of the synthetic lenses transmit UV. (I recall anecdotally they stopped implanting these because of the below e... | [
"The short answer is yes, the bionic eye would need receptors that are responsive to the spectrum (Ultra-Violet and Infrared are just beyond the range of the human visual spectrum) and then it would need to transmit the signal through the optical nerve. Although it's important to note that it's actually the activat... |
[
"How does the gene mutation originated in a single individual becomes the evolutionary change for the whole species?"
] | [
false
] | Suppose an advantageous mutation happens in Eve, then I understand how her descendants would inherit that gene. But even after a millennium or so, the Eve clan would still be an abysmally small percentage of humans as a species. Do multiple individuals go thru the same changes at the same time so that after millions of... | [
"Do not listen to that person. They are wrong. That's not at all how evolution works. For a gene to mutate and then be favorable in a single individual is not evolution, and it doesn't just happen that simply. And favorable genes are not just selected to be passed down. That's a misunderstanding of natural selectio... | [
"If the mutation has a significant survival/reproductive advantage, then non-Eve clan people would be less fit, and Eve clan descendants would comprise a significant proportion of the population. If you're saying that the mutation is advantageous but only in a minor way that doesn't really affect fitness then there... | [
"First of all, since (almost) all cells in our body contain DNA, there are lots of places for mutations to occur; however, not all mutations matter for evolution. Somatic mutations occur in non-reproductive cells and won’t be passed onto offspring. Now, once you have a mutation in a gene that CAN be passed onto a o... |
[
"How can planets within a galaxy maintain their orbit, when their galaxy is being cannibalized by another roaming galaxy? Also, how do galaxies roam around in the first place?"
] | [
false
] | null | [
"Stars within galaxies are spread out incredibly far. Consider the fact that the nearest star to our sun is 4 light years away. Galaxies are mostly empty space.",
"Galaxies roam around under the influences of their own inertia and the gravitational forces exerted upon them by other galaxies"
] | [
"This is the best answer. The space between any significant objects in a galaxy is mind-numbingly vast. Even if two galaxies were to encounter each other head-on, the chances of the objects (stars, planets, whatever) colliding with their respective partner's others is very, very small. However, the gravity with all... | [
"Gravity decreases with the square of the distance. So a planet is influenced much more by the star it orbits around than by an entire galaxy thousands or millions light years away.",
"The same is true for our planet, its orbit is not greatly influenced by the rest of our galaxy."
] |
[
"are compounds / alloys / materials / etc routinely checked to ensure they experience the 'correct' amount of gravity?"
] | [
false
] | To start with, I know this is a stupid question, but I've Googled lots & can't prove it obviously wrong. *everything has mass, easily measured by gravitational effect (weighing it) *everything has a density, again straightforward - mass / volume = density. But do we verify everything is as it should be? We seem to meas... | [
"It sounds sort of like you're asking about the equivalence principle, which says that the mass that makes things difficult to move (inertial mass) is the same as the mass which makes things experience gravity (gravitational mass). The first direct tests of this were done by Lorand Eotvos, and there are some exper... | [
"This",
" is a paper describing an experiment to be performed in the near future to test the weak equivalence principle, which, as ",
"/u/iorgfeflkd",
" mentioned, is very related to what you're asking. So research testing this is still ongoing."
] | [
"Thanks & thanks to InfanticideAquifer too.",
"I knew it was a daft question, but didn't know the name of the principle so my googling was going nowhere. Found it really interesting people are testing actively testing it."
] |
[
"Is IQ a predictor of personality traits, such as empathy or antisocial behavior?"
] | [
false
] | Fairly simple question with, I'm sure, a fairly complicated answer. Is the measurable intelligence of a person in any way related to their likelihood of being a functionally integrated, relatable member of society? Are those with high IQs more likely to be sociopaths, or have higher emotional intelligence? Are those wi... | [
"But it's not quite as simple as it might seem and we'll need to cover a little about statistics. ",
":",
"http://law.jrank.org/pages/1363/Intelligence-Crime-Measuring-size-IQ-crime-correlation.html",
"Terrie Moffitt and colleagues studied 4,552 Danish men born at the end of World War II. They examined intell... | [
"I'd caution you about assuming causation here. It's not hard to imagine that those with criminality risk factors are also unlikely to get a decent education - and the lack of education will reflect as a low score on an IQ test."
] | [
"Statistics like that are unable to reflect the impact of other factors that occur as income rises. In the data referenced, there would need to be further specific study to discover what factors would lead to that decline in relative earning. ",
"For example, some studies have shown that after a particular level ... |
[
"How big would a typical iron magnet have to be to have a field with the same magnitude as the earth's magnetic field?"
] | [
false
] | If you had a normal fridge magnet, how large or massive would it have to be to produce a magnetic field the same size of earth's? | [
"Do you mean magnitude of the magnetic field, or the vector field? If it's the former then a regular fridge magnet actually has a magnetic field 100 times the strength of Earth's. For the latter, you would need a bar magnet the same diameter of the Earth - in fact you can approximate the magnet field of Earth by im... | [
"The Earth's core is a fairly weak magnet in the sense that the maximum magnetic field strength it produces, even inside the core, is weaker than what you get from a fridge magnet. The average internal field inside the core is about 25 Gauss (",
"http://newscenter.berkeley.edu/2010/12/16/earth-magnetic-field/",
... | [
"Surely the bar magnet need not be the size of the earth, just the size of the earth's magnetic core? ",
"Or is the mantle also magnetic? "
] |
[
"If gravity is the curve of spacetime and not a force, then why is it considered one of the four fundamental forces?"
] | [
false
] | The four fundamental forces: Gravity, Electromagnetism, Strong and Weak. But since Einstein, hasn't gravity been considered just the curve of spacetime and not actually a force? So why is it still a "Force"? | [
"Because it's one of the fundamental Things That Affect Stuff. For the reason you describe, scientists sometimes prefer to talk about fundamental ",
"."
] | [
"The other 3 arent really \"forces\" either, force is a Newtonian formulation of mechanics concept. Its dropped in GR and QM/QFT afaik"
] | [
"Makes sense, I figured it was that way, but I just wanted to make sure :)"
] |
[
"Why is it that Zirconium and Hafnium always have traces of the other in their samples?"
] | [
false
] | I read that Hafnium and Zirconium are twin elements and that samples of zirconium and hafnium almost always have atoms of the other. Why is this? | [
"\"The chemical properties of hafnium and zirconium are nearly identical, which makes the two difficult to separate.\" (cf. ",
"http://en.wikipedia.org/wiki/Hafnium",
")"
] | [
"The chemistries of the two elements are extremely similar. They undergo pretty much the same reactions and even have virtually identical atomic radii and ionisation energies, so a sample of one dug out of the ground is likely to contain some of the other because they \"look\" the same in a chemical sense."
] | [
"Thanks. are there anything else like this?"
] |
[
"Why do I see RGB when I look away from a projector light?"
] | [
false
] | Didn't really know how to phrase the question... If I look at the light from a projector, not directly in front but at an angle, and then look away, for an instant I see the light become 3 distinct colors, all showing at the same time side by side by side, Red Green Blue from left to right. This only lasts for a very b... | [
"This is because the DLP projector is rapidly alternating between projection of the red, green, and blue component images. This is called the 'rainbow effect.'",
"Wikipedia has an entry on it"
] | [
"This is it! Thanks!"
] | [
"Very common with DLP projectors, other projection technologies don't do that."
] |
[
"How do fish/whales/dolphins/any aquatic life drink?"
] | [
false
] | null | [
"Mostly they don't.",
"Marine mammals get a lot of their water from their food. They tend to live on meat, because blood and body fluids are a lot less salty than seawater. ",
"Water is also produced as a byproduct of metabolism. When nutrient molecules are broken down to release energy, the largest byproducts ... | [
"Captive dolphins given a freshwater hose to play with drank the water directly and stopped eating. They seem to only eat when motivated by “thirst.”"
] | [
"I'm in the US, but I'm a nurse, and our healthcare industry uses metric. ",
"So when I talk about medical situations or chemical reactions, I tend to think in metric units. When I talk about human activities that I might have to explain to patients, like how much water to drink, I tend to think in freedom units.... |
[
"If I have a heavy workout, does the ensuing repair of my muscles burn more calories over the next xx amount of hours as opposed to the regular resting rate? Any information on this?"
] | [
false
] | [deleted] | [
"Yes, and it is related to the ",
"EPOC effect",
". This is why numerous diets aimed at athletes (Intermittent Fasting, Cheat mode, carb backloading, UD2.0, etc. etc.) have the dieters consuming most of their calories immediately following exercise, to aid in the restorative efforts of the body.",
"In terms o... | [
"you're replacing fat with muscle",
"Well, resistance training does tend to decrease the BFP (body fat percentage), and increase muscular mass, but \"replacing fat with muscle\" is a shorthand that will make many people cringe. Perhaps because it suggests that fat is somehow automagically morphed into muscle, whi... | [
"you're replacing fat with muscle",
"Well, resistance training does tend to decrease the BFP (body fat percentage), and increase muscular mass, but \"replacing fat with muscle\" is a shorthand that will make many people cringe. Perhaps because it suggests that fat is somehow automagically morphed into muscle, whi... |
[
"What does temperature actually mean?"
] | [
false
] | null | [
"Temperature is defined by 1/T = dS/dE.",
"That means that the inverse temperature is the rate of change of entropy with respect to internal energy (at constant volume and number of particles)."
] | [
"That doesn't explain anything at all.",
"Why do you think that?",
"the units of temperature are not the units of what you said.",
"That's incorrect."
] | [
"That doesn't explain anything at all. the units of temperature are not the units of what you said. "
] |
[
"What would it feel like to lick a hydrophobic surface?"
] | [
false
] | null | [
"I cant speak for super-hydrophobic substances, but there are plenty of hydrophobic surfaces in the home. The exact \"taste\" (you wouldn't really taste much, it's more of a physical sensation you're describing) would depend on the texture. Try the following:",
"The frying pan is probably a better representation.... | [
"Those surfaces are understandable because I've had plenty of contact with them. The thought of putting Polystyrene in my mouth makes me feel very uncomfortable!"
] | [
"Apple products taste like the tears of Chinese sweatshop workers. Licking one engenders feelings of bitterness and regret. ",
"Try licking a Droid charger. Its pure euphoria."
] |
[
"How powerful would a laser need to be to reach the bottom of the ocean?"
] | [
false
] | You're in a submersible at the bottom of the marianas trench, a ship above you with a hypothetical laser pointed to the ground in front of you. How strong does this laser need to be to look like a normal laser dot? Alternatively; You have a hypothetical laser at the bottom of the ocean, how strong does it need to be to... | [
"Which would then put the bottom of the trench and the light at the same place, along with everything else. Mission accomplished."
] | [
"Ok so. Seawater absorption is complicated and depends on lots of things (contents of water, wavelength, etc). There's a paper that suggests about 7% per meter under relatively ideal conditions.",
"So multiplying that over the depth of the Mariana trench, you come out with loss such that to get 5 mW of power to t... | [
"It's worse than that, if you ran a laser with that power it for 1 plank time (about 5 *10",
" seconds), you would create a black hole roughly 10",
" times as large as the observable universe. "
] |
[
"Do spacecraft have a way of converting solar energy to propulsion (for use in orbit, not for takeoff)?"
] | [
false
] | [deleted] | [
"There are solar sails, which are just in their early stages of testing. There's also solar powered ion propulsion, but you still need the ions before you can propel them."
] | [
"The word attitude here means orientation. A control moment gyroscope is a way of building up angular momentum by spinning a gyroscope and then transferring some of that angular momentum to the spacecraft by rotating the spinning gyroscope. The resulting torque causes a rotation of the craft which changes its ori... | [
"Unmanned satellites usually carry some propellent onboard for stationkeeping. If you run out of that and can't correct the spacecraft's orbit, you basically have to send up a new one.",
"Spacecraft also have gyroscopes or flywheels for adjusting rotation. Those can be solar powered, as they use electric motors. ... |
[
"Why does it take a few minutes for your eyes to go back to normal after wearing colored glasses? (Ex. bright orange dentist glasses)"
] | [
false
] | null | [
"The glasses change the frequency of the light that your eyes are receiving so then your brain realizes there is an excess of, say red and blue due to those being common for 3D movies, your brain may tone down the amount of red and blue frequency's it is \"outputting\" so once you take the glasses off it has to re... | [
"like when you have to resurface from diving?"
] | [
"What do you mean?"
] |
[
"How \"strong\" of a vacuum can you make by pulling a piston out of a cylinder?"
] | [
false
] | Asking for my dad - he sent the following explanation of his question, and I couldn't really answer: "Suppose you have a piston at the bottom of a cylinder, which has no opening at the bottom. When you draw the piston out, a vacuum is created. It is easy to imagine that very quickly the pressure difference will become ... | [
"You can see see what happens by looking at the ideal gas law: PV=nRT, where P is pressure, V is volume, n is proportional to the number of gas molecules, R is a constant, and T is temperature. Assuming that the temperature and number of gas molecules stay the same, what you are doing is increasing the volume, whic... | [
"The \"theory\" part was already answered, but you also get a lot of technical problems. Once your pressure goes low enough (assuming your sealing holds down to these pressures), the walls of your piston will start outgassing because stuff starts boiling. The water on the walls (there's always a few atomic layers o... | [
"The absolute pressure inside the cylinder drops asymptotically to zero as you pull the piston farther. Approaches zero but does not reach zero. In terms of pressure the differences becomes nil.",
"Once you get below a millionth of an atmosphere you're at the verge of the strange world of high vacuum. At that poi... |
[
"Just thought of traveling with and against light, am i on the right page?"
] | [
false
] | So your in a spaceship traveling away from earth and at the same time you are looking at your family/world through a telescope. Does this mean that what your looking back at is light rays and that it would appear your family is 'frozen' as in your looking at the same rays so its the same image your seeing not a moving ... | [
"you're looking through the telescope and those light rays are hitting your eye faster than usual",
"Here's what happens: you start moving away very fast from the earth, trying to run from the light rays, although classical intuition would tell you that the velocity of the light rays you observe would be smaller,... | [
"Well, first, you can't ever ",
" move at the speed of light. You can get arbitrarily close, however. So let's assume you're moving at a large fraction of the speed of light.",
"For a more thorough discussion of what your friend was talking about, take a look at ",
"this article on the Twin Paradox",
".",
... | [
"The important part is 'increasing' as opposed to distance. "
] |
[
"Could a massive flood create a lake that remains for thousands of years?"
] | [
false
] | Imagine say, a valley in which farmlands were exploited. Would it be possible for a rain-caused flooding to be intense enough to flood the place, and then remain (despite the water cycle leading to evaporation) there pseudo-permanently? Thank you and my apologies if it's a dumb question, this is really far from my scie... | [
"This is similar to what what created the Mediterranean Sea, the event was called the ",
"Zanclean flood",
" and it happened about 5.33 million years ago. Now the Mediterranean sea and the Atlantic are connected--but it wasn't always the case--and the Mediterranean had previously dried up producing 300-1000 m t... | [
"Your question has already been answered sufficiently, but I also have an interesting tidbit to contribute if you'd like;",
"http://en.wikipedia.org/wiki/Reelfoot_Lake",
"Reelfoot Lake, located a few hours from where I live, was formed when a large amount of land sunk and flooded following an earthquake. Origin... | [
"Also worth noting that it's only possible here because the Med is below sea level. It was an inundation by sea water that caused it, not a rainfall event."
] |
[
"How do scientists know that our sun is a 2nd generation star?"
] | [
false
] | null | [
"Actually, the modern theory is that our sun is at least a third generation star in order to explain the heavier elements.",
"There is a detailed recent explanation of this by a Ph.D. astrophysicist here:",
"https://www.forbes.com/sites/startswithabang/2019/10/26/ask-ethan-how-many-generations-of-stars-formed-b... | [
"By its spectrum. First generation stars should only contain helium and hydrogen. The sun has higher metallicity, it contains heavier elements that have to have come from a previous generation. Also, we are here - the nebula from which our solar system coalesced contained the heavy elements to form rocky planets. A... | [
":O Thank you!"
] |
[
"Why is fish meat white while meat from mamals is red?"
] | [
false
] | Basically just the title. I have been told that fish meat is richer in egg white proteins. But i dont really know what that means. And even the doctor told me that, had no idea if that contributed to the colour. | [
"Fish have lower levels of myoglobin which is the protein in muscles responsible for the red colour due to a contained Iron atom. The myoglobin protein is similar to haemoglobin in blood, it carries oxygen. However myoglobin is fixed in the muscle and acts as an oxygen store for when the muscle is under heavy aerob... | [
"On the other hand, some pelagic fishes like tuna pack in a lot more myoglobin, and thus have darker meat."
] | [
"Salmon is not red, but more of a pink orange. This is due to the presence of a pigment called astaxanthin. It is found naturally in the diet of the salmon. Some fisheries that grow salmon will add the pigment into the diet so that the finished meat is more brightly colored. There is nothing 'wrong' with doing this... |
[
"What are the harms of excessive masturbation?"
] | [
false
] | I've been wondering if there is anything unhealthy about it. Can you explain some of the harmful effects and if it is bad, and how much should someone masturbate per week? | [
"Before anyone else tries, yes we all know masturbation is hilarious. But you're in AskScience, so let's try and keep the responses on topic, answering the question, and perhaps even with references."
] | [
"It's possible to give yourself epididymitis, swelling of the epididymis, by excessive masturbation (or excessive intercourse, or especially forceful episodes of either). You could also bruise or rub raw your penis and/or testicles. "
] | [
"There was a study done, but it ",
"showed no significant correlation",
"."
] |
[
"Can technology similar to the Enchroma glasses for the colorblind be used for people to see infrared or ultraviolet?"
] | [
false
] | null | [
"He's not correct. The enchroma glasses work by reducing certain wavelengths so that other ones (the wavelengths a colour blind person has trouble seeing) are more pronounced. This only works for people who can detect those wavelengths, just not well. Since no humans have cones capable of detecting say radio waves,... | [
"Those glasses don't let you see anything you can't already see, they only block certain wavelenghts.",
"In many color-blind people, the red-sensitive cones and the green-sensitive cones have overlapping sensitivity zones. Anything in the overlap will trigger both cones. The glasses simply block all wavelenghts t... | [
"Thanks a lot, that sounds awesome! I hope that we can someday have even more colorful art than we do today."
] |
[
"Do string theorists know or have an idea of what the strings in string theory are made of?"
] | [
false
] | Just a curiosity of mine. I'm watching a documentary on String Theory by NOVA and it's really interesting. | [
"In string theory, the concept of \"being made of\" or of which object is truly the fundamental building block is ill-defined. Strings, along with other objects, are just things that can exist in the theory. Instead of arguing for this abstractly I'll just make one example out of a billion possible ones, so you'll ... | [
"As someone with an interest in string theory, but without the computational chops for something like Polchinski just yet, I love your posts like this one. You can glean some of this stuff from texts without being able to work through the computations, but it's nice to have something that is condensed and somewhere... | [
"Just to add to ",
"/u/rantonels",
" excellent answer, even in non-string theory \"made of\" is a little bit of a nebulous statement. In the Standard Model, an electron, for example, is basically an excitation of \"the electron field\". It's a concrete bundle of energy deposited in a special type of field (a ... |
[
"Does the size (weight, height) of the surrogate mother affect the adult size of the offspring?"
] | [
false
] | null | [
"Probably genetics it’s the most important thing here, but you could probably not discard ambient effects, in this case, the surrogate mother “ambient”. I don’t really know if this have been extensively studied, but a surrogate mother may contribute with hormones, factors or other active molecules that may at the e... | [
"I read some (epigenetics research) a while back that the surrogate mother's body can affect the expression of the baby’s genes. The research was discussed, environmental affects the way the genes are expressed.",
"Researchers have also found occurrences of fetal microchimerism (traces of Male DNA) in their mot... | [
"Not at all unless the surrogate is using her own eggs which is quite rare now in the world of surrogacy. The surrogate has absolutely no genetic influence on the baby.\nThis is what my reproductive endocrinologist told me when I was asking questions about it at one of my appointments (im a surrogate)"
] |
[
"Can I dissolve as much sugar in sea water as I can in distilled water? Why or why not?"
] | [
false
] | Asked fancier: does the concentration of a given solute affect the solvents saturation point for a different solute? EDIT: So there seems to be two camps, one that points out (validly) that theory and logic dictates that more salt=less sugar able to dissolve. The other camp says that's nice but not how it works in real... | [
"Sugar and salt do not share a ",
"common ion",
".",
"One will not directly interfere with the other's equilibrium in water. However, both will compete for water.",
"Competition allows you to ",
"salt out",
" some substances. Check out this ",
"video demonstration of salting out",
" where a solution... | [
"To explain the downvotes - salting out is a proper term for the phenomenon described above"
] | [
"To explain the downvotes - salting out is a proper term for the phenomenon described above"
] |
[
"What theories do we have for how Pluto came to have methane?"
] | [
false
] | In particular, it seems like there are limited processes for abiotic methane formation, e.g. serpentinization. Is this considered a likely scenario? | [
"Exactly what Tiiba said. Methane is the simplest molecule with carbon in it. Ammonia, the simplest with nitrogen. Etc. Since hydrogen is by far the most abundant element, it's clear why we see CH4, NH3, PH3, OH2, and HCl whenever we have an abundance of C, N, P, O, or Cl.",
"What I think is really interesting is... | [
"Why does this say there's one comment, yet not show it?",
"I thought methane is pretty expected when you have carbon and hydrogen. Oxygen makes water, nitrogen - ammonia, phosphorus - phosphine. All this stuff came from a star, and when it cooled down enough to react with hydrogen, it did.",
"There's methane o... | [
"Thanks for the response. Like my response to Tiiba, it's interesting to me that this can happen. It seems unlikely to me that that would occur because it is energetically favorable. What is the source of energy that results in these molecules forming? Radiation from stars?"
] |
[
"Time cloak: how does it work?"
] | [
false
] | I just saw this article ( ) on the front page. In terms that someone who understands at least the basic principles of relativity, quantum mechanics, etc. can understand, how does this work? | [
"It's a fascinatingly simple idea. ",
"A light pulse has a certain bandwidth (i.e. it contains a bunch of different frequencies), which is larger the shorter the pulse is. ",
"In this time-cloaking experiment, they \"pull apart\" this light pulse by accelerating the blue part of the spectrum and slowing down th... | [
"No, not really. Optical manipulation ",
" time manipulation whenever light pulses are used to measure time. In the current example, you can put a dispersive event in the middle of that spectral gap and still you'd never find out at the receiver. The event was cloaked in time. The researchers also provide use cas... | [
"And what do you think is the principle behind the atomic clock? Yes, that's right, a frequency—optical, in the newest and most accurate clocks—measurement.",
"Also, temporal measurement in the context of this experiment can refer to a stable time basis, which can be established via the clock rate of an optical t... |
[
"How do veins and arteries bend/twist without blood getting stopped or clogged?"
] | [
false
] | When a water hose is bent far enough, the flow of water through it is choked and very little water comes out. When we bend our arms or move our legs, shouldnt the same thing happen? | [
"Arteries are sturdier than you think. Thick walled and flexible, arteries can withstand a good amount of compression. As per veins, there is enough collateral circulation that if one gets compressed, the rest of the venous system can compensate."
] | [
"you are right no a point. But cutting of does happen and is a problem, especially in disabled and knocked out people."
] | [
"That's not what happens when a body part goes to sleep.",
"That's usually caused by nerve compression."
] |
[
"Will Mt. McKinley surpass Mt. Everest some day?"
] | [
false
] | I heard that Mt McKinley is still growing. Will it be taller than Everest some day? | [
"Everest is currently growing 1/3 of an inch a year, ",
"source",
". I could not find the rate that McKinley is rising but I did find that the pacific plate is moving northward into Alaska at about 2 inches a year, ",
"souce",
". The source on Everest says that Everest is moving about 5 inches a year. Assum... | [
"This is all fair information to point out, but as a side note, geologically distinguishing Mt. Everest from the plateau it is sitting on is pretty arbitrary. While it makes more sense for climbers/hikers/urban planners/etc to consider the height of the mountain from the surrounding terrain, when it comes to the ge... | [
"I think the down votes are because Olympus mons isn't on earth."
] |
[
"Has flicker noise been explained yet?"
] | [
false
] | Either in electronics/instruments in particular or in general. | [
"It's not always from the same thing. The interesting thing about 1/f noise is that there are a lot of different physical phenomena that can produce it. Mathematically this is the case because a collection of two level fluctuators with a log/normal distribution of switching times gives a 1/f spectrum. The log/norma... | [
"Can you explain your question a bit more? ",
"Noise in electronics",
") is a fact of life, it can be caused by a number of things - thermal nose due to non zero temperature, inteference with the real world.",
"Think about what temperature means classically for a group of atoms in a wire - it means they are j... | [
"Alright. Thanks for the update. I hadn't heard the mathematical argument yet, so I'll ponder that for a while. "
] |
[
"Is “long covid” the same or similar to other post-viral syndromes?"
] | [
false
] | I have been very interested in learning about long haul covid. To my understanding other viruses such as malaria can cause long term symptoms like fatigue and intense pain. A lot of these stories sound similar to the experiences of long COVID patients. Could past research into post-viral syndrome give us clues into how... | [
"This is hard to answer because long COVID isn't clearly defined.",
"There is a post-ICU syndrome that can affect people who get severely ill. They can have permanent functional defects in neurocognitive and cardiopulmonary function. Some are clearly understood, some are not.",
"Some component of long COVID is ... | [
"\"check out treatment of long term covid with CBD oil. Seems there are some promising results\"",
"Just to be clear there are currently ",
"no proven treatments",
"02798-7/fulltext) for long COVID. There are some ",
"ongoing trials",
" evaluating CBD oil but they are far from conclusive. However, doctors... | [
"\"check out treatment of long term covid with CBD oil. Seems there are some promising results\"",
"Just to be clear there are currently ",
"no proven treatments",
"02798-7/fulltext) for long COVID. There are some ",
"ongoing trials",
" evaluating CBD oil but they are far from conclusive. However, doctors... |
[
"If i had 1 mol of a dollar, and was able to spend 1 billion every second, how many years would it take to spend it all?"
] | [
false
] | null | [
"avagadro's number / number of seconds in a year / 1 billion",
"19 million years",
"Bonus: ",
"http://en.wikipedia.org/wiki/Miocene"
] | [
"6.022x10",
" dollars * (1 second / 1 billion dollars) * (1 day / 86400 seconds) * (1 year / 364.25 days) = 19.13 million years"
] | [
"whoops",
"fixed"
] |
[
"What conditions are necessary for protons to decay?"
] | [
false
] | [deleted] | [
"Protons are made up of 3 quarks (2 up quarks and 1 down quark).",
"how/why these seemingly very stable particles would undergo such a process.",
"If you're asking what triggers the decay, it's a completely spontaneous, random event and there is no way of knowing when a proton will decay. It's worth it to ment... | [
"Is it possible that protons simply cannot decay? Or is that impossible from a quantum mechanical point of view?"
] | [
"Certainly the latter.",
"Proton decay isn't very well understood, there are a number of ways that protons are theorised to decay, for example they could break down into a Positron and a Pion (the pion would quickly decay into 2 photons), this process has a predicted half-life of something like 10",
" years.",
... |
[
"Would plants still be green for photosynthesis if we had a different kind of star for our sun?"
] | [
false
] | Let's say we had a blue dwarf, neutrino, or red giant instead of Old Sol. Assuming we were still in a comparable habitable zone and life developed along similar lines, would our plants still be mainly green? | [
"I'm surprised no one has mentioned algae yet. If you take a look at the different types of algae (red, brown, green) you will see that they occupy different trophic zones in the ocean. This means they live at different depths. Green algae are near the surface where red light is in abundance. As you go deeper, red ... | [
"Electromagnetic Radiation is electromagnetic radiation, no matter its source. While the exact emission curves of different stars can vary, and a yellow star might put out more yellow light than a blue star, at the end of the day, plants derive their energy from a fairly wide range of colours of light, 400-700 nm i... | [
"I feel like I've seen a paper on fungus creating blackcholoroplasts to absorb nuclear radiation? Couldn't that develop in plant life on a planet with a weaker magnetic field?",
"found it: ",
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2677413/",
"and it shows that a rise in the melanin fungi rose when eart... |
[
"How do missiles that lock onto vehicles work?"
] | [
false
] | [deleted] | [
"There're multiple guidance methods.",
"Beam-riding is the simplest. A narrow signal is bounced off the target, the missile seeker points the missile at the reflection. Fine for slow-moving or stationary targets, not so great for air-to-air combat when the launcher and the target are both moving at incredibly hig... | [
"Depends on the guidance the missile uses.",
"An infra-red guided missile is said to have locked on when it gets a strong enough heat source to detect and track the target.",
"An active radar guided missile locks on when it constantly moves a radar beam over the target to track it, rather than just scans over i... | [
"thought of a better way to explain it. Beam riding is like if you were in a pitch-black forest and had a missile that fired at whatever you shine a laser-pointer at. You have to continuously track the target with the pointer until it's hit, and you can't use the laser pointer to illuminate your surroundings. SARH ... |
[
"Do we know why people have specific fetishes?"
] | [
false
] | [deleted] | [
"Ignore tag this isn't my area of expertise.",
"The short answer is 'lots of different reasons.'",
"The longer answer is, we don't exactly know but we suspect that many fetishes are a combination of imprinting, classical conditioning, and generalization. Essentially an early or salient presentation of an object... | [
"I have a very, very broad range of fetishes, and can't think of anything in my childhood that's related to pretty much any one of them. So there has to be more than that."
] | [
"I suspect the adolescence thing is probably limited to very specific instances/linked to older theories of sexuality. I think (sadly it was from a talk I heard and I can't find a lit ref) there might be merit to the idea that things present at first sexual experience or sexual encounter are more likely to become f... |
[
"Do children hold an equal amount of DNA from both parents? Is it as perfect 50/50 split?"
] | [
false
] | null | [
"This answer is incorrect, for a couple reasons. First, the Y chromosome is much smaller than the X chromosome. Second, mitocondrial DNA is passed on (almost always) only from the mother; a human embryo has no mtDNA from the sperm (hence the term \"mitochondrial Eve\"). Third, not all chromosomes are exactly the sa... | [
"In rare cases you could have extra chromosomes, so you get two copies of a chromosome from one or both parents. That's definitely not the norm, though.",
"Would the gut fauna that's passed on through the mother's breast milk count? That's not a constant but it definitely has heritable properties."
] | [
"The answer is yes, they do hold an equal amount of DNA from both parents. This is because both parents will each give the child 23 chromosomes, forming the 46 chromosomes the DNA consists of in a cell of a human (pairs of two, one chromosome from the mom and one from the dad). Gender doesn't change the amount of D... |
[
"Can IV medications be given PO?"
] | [
false
] | At the hospital I work at, it is a common practice to reconstitute a gram of vancomycin and then unit dose it into oral cups to be given to the patient by mouth. I've been told we used to use vanco that was intended for oral use but then switched to just using the IV vials. Why can we do this if the vials say "for intr... | [
"Vancomycin is a drug that does not cross the GI tract very well. Therefore, vancomycin given orally does not get into the bloodstream to any great extent, and vancomycin given IV does not get into the gut very well. We primarily use oral vancomycin to treat c. difficile infections (c. difficile lives in the gut, a... | [
"Other IV formulations of drugs can be given through the oral route. I just finished a rotation at a hospital pharmacy and I can think of at least one example. We would dilute IV morphine sulfate with sterile water for injection to yield a concentration of 0.4mg per 1ml for oral use in Neonates. ",
"There are oth... | [
"Pharmacist here. Vancomycin is a bit of a special case because of its absurdly poor oral bioavailability. It's given PO so that it works locally (in the gut) on infections like C. dificile. You won't be getting peaks and troughs with this because it's not really making it into the bloodstream. It's dosed two to... |
[
"In HBO's Chernobyl, it is shown multiple times that merely looking into the exposed nuclear reactor core was particularly dangerous, even compared to just being close enough to do so. Why?"
] | [
false
] | null | [
"Are you referring to the scene where someone is looking over the edge of the hole in the roof, directly at the exposed core?"
] | [
"Yes"
] | [
"Depending on what exactly they’re looking over (the material and it’s thickness) it may or may not be providing good shielding against against neutrons and gamma rays. Also if the burning core is exposed and there’s a plume of contaminated smoke, if you’re standing directly over the hole, you’re probably getting m... |
[
"Why does cortisol's effect in the human body take longer than adrenaline (epinephrine)?"
] | [
false
] | Is it due to the fact that cortisol induces change via gene expression, which takes a lot longer than adrenaline's G-protein coupled cascade is it due to the fact that cortisol has to be made from scratch in the nucleus because of it's lipid character while adrenaline can be stored in vesicles and immediately released?... | [
"The mechanism of action of steroids is much more important than is the way they are synthesized. We know this experimentally because you can take synthesis out of the equation by injecting the hormones as a medicine. An epinephrine shot has an immediate effect on the patient receiving it, but a dose of a glucocort... | [
"Thank you very much for such an in-depth answer to my question! I genuinely appreciate the time you put into this, I now fully understand the difference in speed. I had a Metabolism exam today, which is why I was intrigued by the matter. Again, much thanks! "
] | [
"What class?"
] |
[
"Do humans desire to mate more than any other creature on Earth? If so, why?"
] | [
false
] | [deleted] | [
"Bonobos have even more sex for fun than humans."
] | [
"It's difficult to define as you are throwing around words like \"desire\", \"pleasure\" and \"feeling\" which are all solely human constructs. To answer your question you would have to know how other animals feel which isn't possible.",
"I think the closest you can come to an answer is in the study of masturbat... | [
"Thank you very much for your input and I also learned from reading your reply that there are animals that engage in homosexuality, very interesting. From my understanding humans are the only species that engage in sexual activity while using birth control so it led me to wonder if we're the only species that value... |
[
"What is happening when a chip goes stale?"
] | [
false
] | null | [
"Mostly it is just atmospheric humidity entering the food, making it lose it's crunch. The water activity in a crisp chip is very low, so left exposed to the environment, it will come in contact with water in the air and lose it at a much lower, not even comparable rate. Theoretically this would happen until equili... | [
"This is why moist foods like bread get hard when they go stale while dry foods like chips get soft when they go stale. Both foods are tending towards their equilibrium water composition. "
] | [
"\"On the tub\"?"
] |
[
"What is the material state of jelly?"
] | [
false
] | Title says it all really. | [
"It's a colloidal gel: a solid dispersed into a liquid medium."
] | [
"Specifically, a pectin gel in the US and a gelatin gel in the UK."
] | [
"Are the words gel and jelly related etymologically?"
] |
[
"What are the environmental cons of using hydrogen fuel for transportation?"
] | [
false
] | My mother is curious to know what the negative effects to the environment would be if all cars switched to using hydrogen fuel. | [
"Electrolysis needs energy, so the impact of hydrogen cars would be whatever impact their fuel source has. Luckily, the production process needs electricity, and that can come from any kind of power plant, including solar"
] | [
"But the excess water emitted from the burning of hydrogen fuel wouldn't impact the environment in any way?"
] | [
"The cheapest source of hydrogen comes from extraction of natural gas, the cell in the car requires platinum, the world supply of platinum would not be sufficient to change the American fleet to fuel cells. There is no infrastructure for transporting the hydrogen to the cars. Bottom line there are better solutions ... |
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